{ "$schema_version": "5.3", "review_mode": "fresh", "claim_restatement": { "index_wording": "Gut-origin Parkinson's (Braak Hypothesis)", "entry_form": "phenomenon", "gradeable_restatement": "Sporadic Parkinson disease commonly begins with enteric alpha-synuclein pathology that ascends through vagal connections to the CNS and drives nigrostriatal neurodegeneration.", "restatement_required": true, "split_into": [], "parent_claim": null, "scope_qualifiers": [ { "qualifier": "Prospectively measured prodromal phenotype, baseline CNS/peripheral status and sporadic versus genetic disease", "determinable_before_outcome": true, "determined_from": "Enrollment and experimental design, before results; no responder-defined scope.", "action": "retained" } ] }, "hypothesis": { "name": "Gut-origin Parkinson's (Braak Hypothesis)", "central_claim": "Sporadic Parkinson disease commonly begins with enteric alpha-synuclein pathology that ascends through vagal connections to the CNS and drives nigrostriatal neurodegeneration.", "proposed_mechanism": "Sporadic Parkinson disease commonly begins with enteric alpha-synuclein pathology that ascends through vagal connections to the CNS and drives nigrostriatal neurodegeneration.", "claimed_scope": "Sporadic Parkinson disease commonly begins with enteric alpha-synuclein pathology that ascends through vagal connections to the CNS and drives nigrostriatal neurodegeneration.", "claimed_level": [ "initiation", "vagal propagation", "common sporadic origin" ], "is_conjunctive": true, "conjunctive_note": "The SC3 gate tests common gut-origin attribution across sporadic PD. Body-first subtype evidence, vagal transport and origin are distinct; RBD and measured baseline autonomic states may define prospective subgroups, but responders or post-outcome exceptions may not." }, "rubric_routing": { "primary_rubric": "01-neurodegeneration.md", "secondary_rubrics": [ "04-microbiome-systemic.md" ], "index_notes_applied": [ "The SC3 gate tests common gut-origin attribution across sporadic PD. Body-first subtype evidence, vagal transport and origin are distinct; RBD and measured baseline autonomic states may define prospective subgroups, but responders or post-outcome exceptions may not." ], "rubric_fit_note": "Exact archived v5.3 framework. Any stale index empirical framing is rechecked against primary results." }, "subclaim_matrix": { "subclaims": [ { "id": "SC1", "statement": "Enteric pathology precedes CNS pathology.", "subclaim_type": "existence", "scope": "sporadic PD and prospectively measured prodromal subtypes", "claimed_scope": "sporadic PD and prospectively measured prodromal subtypes", "governing_rubric": "01-neurodegeneration.md", "key_evidence_anchor": "Longitudinal peripheral and central measures", "hsef_level": "Γ", "confidence": "Moderate", "governing_cap_or_threshold": "Quoted boundary and upward audit below.", "rationale": "Premotor enteric pathology and autonomic dysfunction are reproducible in selected groups, but motor diagnosis is not the onset of CNS pathology. Serial paired gut and central seed measurements establishing enteric-before-CNS order are absent from the examined causal case; sampled autopsies provide contrary patterns." }, { "id": "SC2", "statement": "Endogenous pathological alpha-synuclein transfers from gut through vagal connections to CNS.", "subclaim_type": "mechanism", "scope": "native disease trajectories rather than forced injection alone", "claimed_scope": "native disease trajectories rather than forced injection alone", "governing_rubric": "01-neurodegeneration.md", "key_evidence_anchor": "Endogenous tracing or controlled vagotomy natural experiment", "hsef_level": "Γ", "confidence": "Moderate", "governing_cap_or_threshold": "Quoted boundary and upward audit below.", "rationale": "Vagal continuity is causally relevant in imposed-seed and engineered gut-mucosal systems. The latter generates seeds in situ and is credited beyond injected fibrils, yet uses human transgenes and does not establish nigral loss. Registry vagotomy is suggestive but not a rigorously isolated natural-origin instrument; the native human disease route remains plausible without a demonstrated dependency." }, { "id": "SC3", "statement": "Gut-origin accounts for a meaningful common fraction of sporadic PD.", "subclaim_type": "primacy", "scope": "sporadic human PD including brain-first and body-first presentations", "claimed_scope": "sporadic human PD including brain-first and body-first presentations", "governing_rubric": "01-neurodegeneration.md", "key_evidence_anchor": "Prospective origin attribution with subtype prevalence", "hsef_level": "Γ", "confidence": "Moderate", "governing_cap_or_threshold": "Quoted boundary and upward audit below.", "rationale": "No examined study prospectively attributes a meaningful common fraction of sporadic human PD to enteric seeds before CNS disease. Body-first phenotype, sympathetic-first pathology and inferred cross-sectional stage assignments are not synonymous with gut-first vagal initiation. Stronger model results do not supply this registered scope gate." } ], "aggregation_rule": "scope-matched", "aggregation_preregistered": true, "aggregation_rationale": "The SC3 gate tests common gut-origin attribution across sporadic PD. Body-first subtype evidence, vagal transport and origin are distinct; RBD and measured baseline autonomic states may define prospective subgroups, but responders or post-outcome exceptions may not.", "primary_subclaim_id": "SC3", "aggregation_derivation": "Γ for the registered common sporadic enteric-vagal initiation claim. Scope-matched aggregation uses SC3; primary-subclaim and weakest-link sensitivities also return Γ. The assembled evidence exceeds association alone through timing, animal pathway tests and human natural experiments, but does not cross the full-scope initiation dependency threshold. Conditional transport capability is established in particular engineered models, and human body-first phenotypes are separately supported; neither is silently substituted for common natural gut initiation.", "aggregation_alternatives": { "weakest_link_would_return": "Γ", "primary_subclaim_would_return": "Γ", "scope_matched_would_return": "Γ", "note": "Separate narrow successes do not replace the preregistered gate." }, "index_rule_deviation": "" }, "competing_models": { "models_evaluated": [ { "rank_in_tournament": 1, "model_id": "M3", "is_nominal": false, "name": "Heterogeneous body-first and brain-first trajectories", "core_claim": "Different individuals have peripheral-predominant or brain-predominant early dysfunction.", "explains_what_nominal_does_not": "Different individuals have peripheral-predominant or brain-predominant early dysfunction.", "strongest_supporting_evidence": [ "Multimodal imaging, longitudinal clinical comparisons and early autopsy patterns fit heterogeneity (PMID32830221, PMID40204988, PMID40082617)." ], "strongest_contradictory_evidence": [ "RBD proxies and a population-based contrary classification study limit a strict binary causal-origin taxonomy (PMID38860478)." ], "hsef_level_for_this_model": "Γ", "rationale": "Multimodal imaging, longitudinal clinical comparisons and early autopsy patterns fit heterogeneity (PMID32830221, PMID40204988, PMID40082617). RBD proxies and a population-based contrary classification study limit a strict binary causal-origin taxonomy (PMID38860478)." }, { "rank_in_tournament": 2, "model_id": "M2", "is_nominal": false, "name": "Brain-first descending dissemination", "core_claim": "Central pathology can precede peripheral involvement and spread outward.", "explains_what_nominal_does_not": "Central pathology can precede peripheral involvement and spread outward.", "strongest_supporting_evidence": [ "Vagus/stomach autopsies and noncanonical DMV-negative cases, with primate bidirectionality, support this possibility (PMID34151862, PMID18053026, PMID32380543)." ], "strongest_contradictory_evidence": [ "Late autopsy sampling cannot exclude earlier transient peripheral seeds; other autopsies show isolated sympathetic disease." ], "hsef_level_for_this_model": "Γ", "rationale": "Vagus/stomach autopsies and noncanonical DMV-negative cases, with primate bidirectionality, support this possibility (PMID34151862, PMID18053026, PMID32380543). Late autopsy sampling cannot exclude earlier transient peripheral seeds; other autopsies show isolated sympathetic disease." }, { "rank_in_tournament": 3, "model_id": "M5", "is_nominal": false, "name": "Indirect microbial and immune risk modification", "core_claim": "Gut perturbations can affect nigral vulnerability through metabolites, barrier and immune pathways.", "explains_what_nominal_does_not": "Gut perturbations can affect nigral vulnerability through metabolites, barrier and immune pathways.", "strongest_supporting_evidence": [ "Native colitis/CD8 and microbial UrdA-ImP perturbations provide bounded causal contributions with neuronal/functional outcomes (PMID34412704, PMID40913049)." ], "strongest_contradictory_evidence": [ "Conditioned animals and postdiagnostic human associations do not establish common human initiation or a specific vagal mediator." ], "hsef_level_for_this_model": "Ε", "rationale": "Native colitis/CD8 and microbial UrdA-ImP perturbations provide bounded causal contributions with neuronal/functional outcomes (PMID34412704, PMID40913049). Conditioned animals and postdiagnostic human associations do not establish common human initiation or a specific vagal mediator." }, { "rank_in_tournament": 4, "model_id": "M1", "is_nominal": true, "name": "Common enteric-vagal origin", "core_claim": "Enteric seeds usually initiate sporadic PD and ascend to cause nigral degeneration.", "explains_what_nominal_does_not": "Enteric seeds usually initiate sporadic PD and ascend to cause nigral degeneration.", "strongest_supporting_evidence": [ "Premotor biopsy, suggestive truncal-vagotomy associations and conditional gut-seeding/epithelial models supply the strongest case." ], "strongest_contradictory_evidence": [ "No common origin fraction, paired pre-CNS sequence or human route dependency is demonstrated; negative spread and alternative anatomical trajectories remain." ], "hsef_level_for_this_model": "Γ", "rationale": "Premotor biopsy, suggestive truncal-vagotomy associations and conditional gut-seeding/epithelial models supply the strongest case. No common origin fraction, paired pre-CNS sequence or human route dependency is demonstrated; negative spread and alternative anatomical trajectories remain." }, { "rank_in_tournament": 5, "model_id": "M4", "is_nominal": false, "name": "Parallel multi-organ vulnerability", "core_claim": "A shared systemic/genetic insult affects gut and brain without obligatory seed transfer.", "explains_what_nominal_does_not": "A shared systemic/genetic insult affects gut and brain without obligatory seed transfer.", "strongest_supporting_evidence": [ "Global c-rel and inflammatory/genotype models plus multiple non-vagal mechanisms are compatible (PMID41207395, PMID38750146)." ], "strongest_contradictory_evidence": [ "Specific source-to-recipient transfer and vagotomy blockade in engineered models cannot be explained by parallel injury alone." ], "hsef_level_for_this_model": "Γ", "rationale": "Global c-rel and inflammatory/genotype models plus multiple non-vagal mechanisms are compatible (PMID41207395, PMID38750146). Specific source-to-recipient transfer and vagotomy blockade in engineered models cannot be explained by parallel injury alone." } ], "tournament_summary": "Descriptive comparison; does not modify the nominal score. Longitudinal gut/CSF seed assays and autonomic/dopamine imaging starting before RBD, followed by a selective mediator perturbation, distinguish true enteric ascent from a peripheral phenotype accompanying early central disease. RBD alone cannot define the initiating tissue.", "study_separating_rank1_from_rank2": "Longitudinal gut/CSF seed assays and autonomic/dopamine imaging starting before RBD, followed by a selective mediator perturbation, distinguish true enteric ascent from a peripheral phenotype accompanying early central disease. RBD alone cannot define the initiating tissue.", "nominal_wins_only_by_funding_artifact": false, "level_unchanged_by_tournament": true }, "evidence_inventory": [ { "n": 1, "pmid": "1972853", "title": "Parkinson's disease: an immunohistochemical study of Lewy body-containing neurons in the enteric nervous system.", "citation": "Wakabayashi K, Takahashi H, Ohama E et al. Parkinson's disease: an immunohistochemical study of Lewy body-containing neurons in the enteric nervous system. Acta neuropathologica. 1990.", "doi": "10.1007/BF00294234", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/1972853/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/1972853/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID1972853", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Autopsies identified Lewy bodies in selected enteric neuronal phenotypes, establishing peripheral involvement in diagnosed PD.", "what_it_does_not_show": "Three end-stage observations do not establish temporal origin, gut-to-brain movement or common-fraction causation.", "confounders_present": [ "Three end-stage observations do not establish temporal origin, gut-to-brain movement or common-fraction causation." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 2, "pmid": "12498954", "title": "Staging of brain pathology related to sporadic Parkinson's disease.", "citation": "Braak H, Del Tredici K, Rüb U et al. Staging of brain pathology related to sporadic Parkinson's disease. Neurobiology of aging. 2003.", "doi": "10.1016/s0197-4580(02)00065-9", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/12498954/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/12498954/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID12498954", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Cross-sectional incidental and symptomatic brain pathology supported a caudo-rostral staging scheme beginning in selected brainstem/olfactory sites.", "what_it_does_not_show": "A topographical stage reconstruction is not longitudinal transport and does not demonstrate enteric initiation before CNS pathology.", "confounders_present": [ "A topographical stage reconstruction is not longitudinal transport and does not demonstrate enteric initiation before CNS pathology." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 3, "pmid": "20306269", "title": "Multi-organ distribution of phosphorylated alpha-synuclein histopathology in subjects with Lewy body disorders.", "citation": "Beach TG, Adler CH, Sue LI et al. Multi-organ distribution of phosphorylated alpha-synuclein histopathology in subjects with Lewy body disorders. Acta neuropathologica. 2010.", "doi": "10.1007/s00401-010-0664-3", "pmcid": "PMC2866090", "url": "https://pubmed.ncbi.nlm.nih.gov/20306269/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/20306269/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID20306269", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Systematic multi-organ autopsy staining mapped widespread Lewy pathology with a decreasing upper-to-lower gastrointestinal gradient.", "what_it_does_not_show": "Anatomical distribution at death cannot determine direction or initiating organ; peripheral involvement is compatible with descending or parallel disease.", "confounders_present": [ "Anatomical distribution at death cannot determine direction or initiating organ; peripheral involvement is compatible with descending or parallel disease." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 4, "pmid": "16042314", "title": "Staging of sporadic Parkinson disease-related alpha-synuclein pathology: inter- and intra-rater reliability.", "citation": "Müller CM, de Vos RA, Maurage CA et al. Staging of sporadic Parkinson disease-related alpha-synuclein pathology: inter- and intra-rater reliability. Journal of neuropathology and experimental neurology. 2005.", "doi": "10.1097/01.jnen.0000171652.40083.15", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/16042314/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/16042314/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID16042314", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Observers across institutions reproducibly assigned brain alpha-synuclein stages using a defined section protocol.", "what_it_does_not_show": "Reliability of a classification validates measurement consistency, not temporal order, vagal transmission or etiologic necessity.", "confounders_present": [ "Reliability of a classification validates measurement consistency, not temporal order, vagal transmission or etiologic necessity." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 5, "pmid": "18297293", "title": "Applicability of current staging/categorization of alpha-synuclein pathology and their clinical relevance.", "citation": "Parkkinen L, Pirttilä T, Alafuzoff I et al. Applicability of current staging/categorization of alpha-synuclein pathology and their clinical relevance. Acta neuropathologica. 2008.", "doi": "10.1007/s00401-008-0346-6", "pmcid": "PMC2270355", "url": "https://pubmed.ncbi.nlm.nih.gov/18297293/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/18297293/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID18297293", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "An unselected alpha-synuclein-positive autopsy series contained deviations from the proposed caudo-rostral pattern and substantial pathology without corresponding clinical syndromes.", "what_it_does_not_show": "Deviation undermines universal staging but does not exclude a gut-origin subtype; cross-sectional pathology cannot reconstruct an individual's initiating sequence.", "confounders_present": [ "Deviation undermines universal staging but does not exclude a gut-origin subtype; cross-sectional pathology cannot reconstruct an individual's initiating sequence." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 6, "pmid": "21766334", "title": "Alpha-synuclein in colonic submucosa in early untreated Parkinson's disease.", "citation": "Shannon KM, Keshavarzian A, Mutlu E et al. Alpha-synuclein in colonic submucosa in early untreated Parkinson's disease. Movement disorders : official journal of the Movement Disorder Society. 2012.", "doi": "10.1002/mds.23838", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/21766334/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/21766334/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID21766334", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Early untreated PD sigmoid biopsies showed a nerve-fibre staining pattern absent from the tested healthy and inflammatory controls.", "what_it_does_not_show": "Patients already had motor PD; staining specificity is assay-dependent and does not locate the disease origin before CNS pathology.", "confounders_present": [ "Patients already had motor PD; staining specificity is assay-dependent and does not locate the disease origin before CNS pathology." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 7, "pmid": "22550057", "title": "Is alpha-synuclein in the colon a biomarker for premotor Parkinson's disease? Evidence from 3 cases.", "citation": "Shannon KM, Keshavarzian A, Dodiya HB et al. Is alpha-synuclein in the colon a biomarker for premotor Parkinson's disease? Evidence from 3 cases. Movement disorders : official journal of the Movement Disorder Society. 2012.", "doi": "10.1002/mds.25020", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/22550057/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/22550057/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID22550057", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Archived colon biopsies from three future PD patients contained alpha-synuclein staining before their first motor symptom.", "what_it_does_not_show": "Premotor is not pre-CNS; retrospective cases, small numbers and healthy control selection do not determine population prevalence or causal route.", "confounders_present": [ "Premotor is not pre-CNS; retrospective cases, small numbers and healthy control selection do not determine population prevalence or causal route." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 8, "pmid": "24240814", "title": "Accumulation of α-synuclein in the bowel of patients in the pre-clinical phase of Parkinson's disease.", "citation": "Hilton D, Stephens M, Kirk L et al. Accumulation of α-synuclein in the bowel of patients in the pre-clinical phase of Parkinson's disease. Acta neuropathologica. 2014.", "doi": "10.1007/s00401-013-1214-6", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/24240814/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/24240814/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID24240814", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Blinded archived gastrointestinal biopsy analysis detected phosphorylated nerve pathology in some patients years before motor onset, including serial samples.", "what_it_does_not_show": "Sparse sensitivity and retrospectively ascertained diagnoses limit generalization; no contemporaneous CNS measurements exclude earlier brain disease.", "confounders_present": [ "Sparse sensitivity and retrospectively ascertained diagnoses limit generalization; no contemporaneous CNS measurements exclude earlier brain disease." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 9, "pmid": "27015771", "title": "Pathological α-synuclein in gastrointestinal tissues from prodromal Parkinson disease patients.", "citation": "Stokholm MG, Danielsen EH, Hamilton-Dutoit SJ et al. Pathological α-synuclein in gastrointestinal tissues from prodromal Parkinson disease patients. Annals of neurology. 2016.", "doi": "10.1002/ana.24648", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/27015771/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27015771/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27015771", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Archived gastrointestinal phosphorylated alpha-synuclein staining was detected in 22 of 39 prodromal subjects, sampled on average seven years before diagnosis.", "what_it_does_not_show": "Premotor detection does not establish pre-CNS origin; aggregated-alpha-synuclein staining did not differ from controls, and retrospective tissue ascertainment and assay choice constrain prevalence.", "confounders_present": [ "Premotor detection does not establish pre-CNS origin; aggregated-alpha-synuclein staining did not differ from controls, and retrospective tissue ascertainment and assay choice constrain prevalence." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 10, "pmid": "27044604", "title": "Evaluation of alpha-synuclein immunohistochemical methods for the detection of Lewy-type synucleinopathy in gastrointestinal biopsies.", "citation": "Corbillé AG, Letournel F, Kordower JH et al. Evaluation of alpha-synuclein immunohistochemical methods for the detection of Lewy-type synucleinopathy in gastrointestinal biopsies. Acta neuropathologica communications. 2016.", "doi": "10.1186/s40478-016-0305-8", "pmcid": "PMC4820972", "url": "https://pubmed.ncbi.nlm.nih.gov/27044604/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27044604/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27044604", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "A multicentre assessment found frequent positive control-biopsy staining and no tested method or pattern with both sensitivity and specificity above 80 percent.", "what_it_does_not_show": "Small shared biopsy sets and heterogeneous ratings test assay reliability rather than excluding enteric disease or its causal route.", "confounders_present": [ "Small shared biopsy sets and heterogeneous ratings test assay reliability rather than excluding enteric disease or its causal route." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Shared biopsy staining/rater assessment platform with follow-up full-thickness study; specimens differ." ] }, { "n": 11, "pmid": "27589538", "title": "Multicenter Assessment of Immunohistochemical Methods for Pathological Alpha-Synuclein in Sigmoid Colon of Autopsied Parkinson's Disease and Control Subjects.", "citation": "Beach TG, Corbillé AG, Letournel F et al. Multicenter Assessment of Immunohistochemical Methods for Pathological Alpha-Synuclein in Sigmoid Colon of Autopsied Parkinson's Disease and Control Subjects. Journal of Parkinson's disease. 2016.", "doi": "10.3233/JPD-160888", "pmcid": "PMC5501392", "url": "https://pubmed.ncbi.nlm.nih.gov/27589538/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27589538/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27589538", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Full-thickness autopsy-colon assessment achieved better discrimination with selected protocols and trained raters, including a perfect result for one method in the tested set.", "what_it_does_not_show": "Selected small specimens, sufficient submucosa and reader training limit generalization; shares assay-development components with the earlier biopsy assessment, not independent origin evidence.", "confounders_present": [ "Selected small specimens, sufficient submucosa and reader training limit generalization; shares assay-development components with the earlier biopsy assessment, not independent origin evidence." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Follow-up assay development programme; new autopsy tissue does not supply an independent origin experiment." ] }, { "n": 12, "pmid": "25589666", "title": "Colonic mucosal a-synuclein lacks specificity as a biomarker for Parkinson disease.", "citation": "Visanji NP, Marras C, Kern DS et al. Colonic mucosal a-synuclein lacks specificity as a biomarker for Parkinson disease. Neurology. 2015.", "doi": "10.1212/WNL.0000000000001240", "pmcid": "PMC4335990", "url": "https://pubmed.ncbi.nlm.nih.gov/25589666/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/25589666/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID25589666", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "PET-blot and routine immunohistochemistry detected mucosal alpha-synuclein aggregates in many healthy controls as well as PD, including all 11 PET-blot controls.", "what_it_does_not_show": "Assay non-specificity undermines biopsy biomarker interpretation; mucosal staining does not exclude pathogenic conformations in other enteric compartments.", "confounders_present": [ "Assay non-specificity undermines biopsy biomarker interpretation; mucosal staining does not exclude pathogenic conformations in other enteric compartments." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 13, "pmid": "27324838", "title": "Similar α-Synuclein staining in the colon mucosa in patients with Parkinson's disease and controls.", "citation": "Antunes L, Frasquilho S, Ostaszewski M et al. Similar α-Synuclein staining in the colon mucosa in patients with Parkinson's disease and controls. Movement disorders : official journal of the Movement Disorder Society. 2016.", "doi": "10.1002/mds.26702", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/27324838/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27324838/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27324838", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "Blinded right and left colon assessment found similar alpha-synuclein and phosphorylated staining in 19 PD patients and eight controls.", "what_it_does_not_show": "Small cross-sectional samples and antibody patterns cannot determine initiating site, transport direction or the absence of a gut-origin subgroup.", "confounders_present": [ "Small cross-sectional samples and antibody patterns cannot determine initiating site, transport direction or the absence of a gut-origin subgroup." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 14, "pmid": "34151862", "title": "Vagus Nerve and Stomach Synucleinopathy in Parkinson's Disease, Incidental Lewy Body Disease, and Normal Elderly Subjects: Evidence Against the \"Body-First\" Hypothesis.", "citation": "Beach TG, Adler CH, Sue LI et al. Vagus Nerve and Stomach Synucleinopathy in Parkinson's Disease, Incidental Lewy Body Disease, and Normal Elderly Subjects: Evidence Against the \"Body-First\" Hypothesis. Journal of Parkinson's disease. 2021.", "doi": "10.3233/JPD-212733", "pmcid": "PMC10082635", "url": "https://pubmed.ncbi.nlm.nih.gov/34151862/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/34151862/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID34151862", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "Autopsies spanning normal elderly, incidental Lewy pathology and PD found no vagal or gastric phosphorylated-synuclein positivity without brain pathology.", "what_it_does_not_show": "Cross-sectional age-related ascertainment, sampled gut regions and detection sensitivity leave transient or unsampled peripheral initiation possible; this is positive counterevidence to a common obligatory sequence, not universal proof of brain-first disease.", "confounders_present": [ "Cross-sectional age-related ascertainment, sampled gut regions and detection sensitivity leave transient or unsampled peripheral initiation possible; this is positive counterevidence to a common obligatory sequence, not universal proof of brain-first disease." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 15, "pmid": "29422109", "title": "Lack of pathogenic potential of peripheral α-synuclein aggregates from Parkinson's disease patients.", "citation": "Recasens A, Carballo-Carbajal I, Parent A et al. Lack of pathogenic potential of peripheral α-synuclein aggregates from Parkinson's disease patients. Acta neuropathologica communications. 2018.", "doi": "10.1186/s40478-018-0509-1", "pmcid": "PMC5806361", "url": "https://pubmed.ncbi.nlm.nih.gov/29422109/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/29422109/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID29422109", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "contradicts", "what_it_shows": "Human stellate-ganglion Lewy-body extracts injected intracerebrally did not reproduce the long-term nigral degeneration previously seen with nigral extracts.", "what_it_does_not_show": "Imposed intracerebral inoculation and sympathetic rather than enteric tissue do not test natural gut initiation; they show that peripheral seed source and conformation can affect pathogenicity.", "confounders_present": [ "Imposed intracerebral inoculation and sympathetic rather than enteric tissue do not test natural gut initiation; they show that peripheral seed source and conformation can affect pathogenicity." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 16, "pmid": "32747521", "title": "In vivo distribution of α-synuclein in multiple tissues and biofluids in Parkinson disease.", "citation": "Chahine LM, Beach TG, Brumm MC et al. In vivo distribution of α-synuclein in multiple tissues and biofluids in Parkinson disease. Neurology. 2020.", "doi": "10.1212/WNL.0000000000010404", "pmcid": "PMC7538226", "url": "https://pubmed.ncbi.nlm.nih.gov/32747521/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/32747521/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID32747521", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "The six-site S4 study compared multiple fluid and tissue alpha-synuclein measures in 59 PD patients and 21 controls and reported limited sensitivity for skin and submandibular staining.", "what_it_does_not_show": "Cross-sectional diagnosed disease does not identify origin; the abstract does not report a colon result, and measurements across compartments were not correlated.", "confounders_present": [ "Cross-sectional diagnosed disease does not identify origin; the abstract does not report a colon result, and measurements across compartments were not correlated." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 17, "pmid": "26031848", "title": "Vagotomy and subsequent risk of Parkinson's disease.", "citation": "Svensson E, Horváth-Puhó E, Thomsen RW et al. Vagotomy and subsequent risk of Parkinson's disease. Annals of neurology. 2015.", "doi": "10.1002/ana.24448", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/26031848/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/26031848/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID26031848", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "Danish registry comparisons associated truncal vagotomy over 20 years before follow-up with lower PD risk than the general population; selective vagotomy was not protective.", "what_it_does_not_show": "Overall and direct truncal-versus-selective estimates were imprecise and crossed unity; surgical indication, smoking and long-survival selection remain alternative explanations, without direct alpha-synuclein mediator measurement.", "confounders_present": [ "Overall and direct truncal-versus-selective estimates were imprecise and crossed unity; surgical indication, smoking and long-survival selection remain alternative explanations, without direct alpha-synuclein mediator measurement." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 18, "pmid": "28446653", "title": "Vagotomy and Parkinson disease: A Swedish register-based matched-cohort study.", "citation": "Liu B, Fang F, Pedersen NL et al. Vagotomy and Parkinson disease: A Swedish register-based matched-cohort study. Neurology. 2017.", "doi": "10.1212/WNL.0000000000003961", "pmcid": "PMC5440238", "url": "https://pubmed.ncbi.nlm.nih.gov/28446653/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/28446653/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Swedish-register-overlapping-source", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:RESULTS, 2:DISCUSSION. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "Swedish matched registries found no overall vagotomy association but lower PD hazard for truncal procedures at least five years before diagnosis, without a selective-vagotomy effect.", "what_it_does_not_show": "The truncal overall estimate crossed unity; procedure era, ulcer indication, proxy adjustment and nonrandom exposure constrain route-specific causation and cannot quantify the gut-origin fraction.", "confounders_present": [ "The truncal overall estimate crossed unity; procedure era, ulcer indication, proxy adjustment and nonrandom exposure constrain route-specific causation and cannot quantify the gut-origin fraction." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 19, "pmid": "30381408", "title": "The vermiform appendix impacts the risk of developing Parkinson's disease.", "citation": "Killinger BA, Madaj Z, Sikora JW et al. The vermiform appendix impacts the risk of developing Parkinson's disease. Science translational medicine. 2018.", "doi": "10.1126/scitranslmed.aar5280", "pmcid": "PMC6319259", "url": "https://pubmed.ncbi.nlm.nih.gov/30381408/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/30381408/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Swedish-register-plus-PPMI", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "Swedish and PPMI analyses associated earlier appendectomy with lower risk or delayed onset, while normal appendix lysates contained aggregation-associated alpha-synuclein forms.", "what_it_does_not_show": "Appendectomy changes immunity and microbial niches as well as a possible seed reservoir; effects varied by geography and genetic status and do not directly measure ascending vagal transfer.", "confounders_present": [ "Appendectomy changes immunity and microbial niches as well as a possible seed reservoir; effects varied by geography and genetic status and do not directly measure ascending vagal transfer." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Swedish national population can overlap later Swedish case-control sampling; separate PPMI component." ] }, { "n": 20, "pmid": "32830221", "title": "Brain-first versus body-first Parkinson's disease: a multimodal imaging case-control study.", "citation": "Horsager J, Andersen KB, Knudsen K et al. Brain-first versus body-first Parkinson's disease: a multimodal imaging case-control study. Brain : a journal of neurology. 2020.", "doi": "10.1093/brain/awaa238", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/32830221/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/32830221/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Danish-iRBD-imaging-overlap", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Multimodal imaging separated RBD-associated autonomic dysfunction with relatively preserved dopamine storage from diagnosed PD without RBD dominated by nigrostriatal dysfunction.", "what_it_does_not_show": "Cross-sectional trajectory inference, overlapping iRBD comparator participants and functional imaging rather than direct seed tracking do not identify a uniquely enteric initiating site.", "confounders_present": [ "Cross-sectional trajectory inference, overlapping iRBD comparator participants and functional imaging rather than direct seed tracking do not identify a uniquely enteric initiating site." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 21, "pmid": "29866443", "title": "In-vivo staging of pathology in REM sleep behaviour disorder: a multimodality imaging case-control study.", "citation": "Knudsen K, Fedorova TD, Hansen AK et al. In-vivo staging of pathology in REM sleep behaviour disorder: a multimodality imaging case-control study. The Lancet. Neurology. 2018.", "doi": "10.1016/S1474-4422(18)30162-5", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/29866443/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/29866443/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Danish-iRBD-imaging-overlap", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Twenty-two iRBD patients had extensive autonomic and locus-coeruleus abnormalities while most retained normal-range putaminal dopamine storage.", "what_it_does_not_show": "RBD already involves CNS circuitry; normative comparator data and functional dysfunction gradients do not demonstrate a gut-before-CNS sequence; iRBD participants overlap the later subtype study.", "confounders_present": [ "RBD already involves CNS circuitry; normative comparator data and functional dysfunction gradients do not demonstrate a gut-before-CNS sequence; iRBD participants overlap the later subtype study." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 22, "pmid": "37059509", "title": "Assessment of heterogeneity among participants in the Parkinson's Progression Markers Initiative cohort using α-synuclein seed amplification: a cross-sectional study.", "citation": "Siderowf A, Concha-Marambio L, Lafontant DE et al. Assessment of heterogeneity among participants in the Parkinson's Progression Markers Initiative cohort using α-synuclein seed amplification: a cross-sectional study. The Lancet. Neurology. 2023.", "doi": "10.1016/S1474-4422(23)00109-6", "pmcid": "PMC10627170", "url": "https://pubmed.ncbi.nlm.nih.gov/37059509/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/37059509/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PPMI-overlapping-source-cohort", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "PPMI cerebrospinal-fluid seed amplification classified diagnosed and many prodromal patients and showed substantial olfactory and genetic subgroup heterogeneity.", "what_it_does_not_show": "Diagnostic performance and prodromal positivity do not locate the seed origin; repeated PPMI analyses are not independent patient cohorts and some normal-olfaction cases were seed-negative.", "confounders_present": [ "Diagnostic performance and prodromal positivity do not locate the seed origin; repeated PPMI analyses are not independent patient cohorts and some normal-olfaction cases were seed-negative." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 23, "pmid": "38834646", "title": "Disease progression in proposed brain-first and body-first Parkinson's disease subtypes.", "citation": "Xu Z, Hu T, Xu C et al. Disease progression in proposed brain-first and body-first Parkinson's disease subtypes. NPJ Parkinson's disease. 2024.", "doi": "10.1038/s41531-024-00730-1", "pmcid": "PMC11150376", "url": "https://pubmed.ncbi.nlm.nih.gov/38834646/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/38834646/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38834646", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results, 2:Discussion, 3:Methods. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Possible premotor-RBD grouping predicted more rapid longitudinal motor-score progression than PD without possible RBD.", "what_it_does_not_show": "Original Methods identify a Huashan Hospital cohort of 137 patients, not PPMI. Questionnaire-based RBD, retrospective premotor recall, sex differences and treatment-adjusted observational follow-up do not verify enteric origin.", "confounders_present": [ "Original Methods identify a Huashan Hospital cohort of 137 patients, not PPMI. Questionnaire-based RBD, retrospective premotor recall, sex differences and treatment-adjusted observational follow-up do not verify enteric origin." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Independent Huashan clinical cohort verified in original Methods; not PPMI." ] }, { "n": 24, "pmid": "40542411", "title": "Clinical progression and genetic pathways in body-first and brain-first Parkinson's disease.", "citation": "Passaretti M, Veréb D, Mijalkov M et al. Clinical progression and genetic pathways in body-first and brain-first Parkinson's disease. Molecular neurodegeneration. 2025.", "doi": "10.1186/s13024-025-00866-5", "pmcid": "PMC12181842", "url": "https://pubmed.ncbi.nlm.nih.gov/40542411/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/40542411/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "ErratumIn: PMID40830880" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PPMI-overlapping-source-cohort", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Longitudinal PPMI symptom, imaging and genetic analyses supported stable body-first and brain-first phenotype distinctions and different progression patterns.", "what_it_does_not_show": "Shares PPMI data with other reports; proxy-defined subtypes do not identify first tissue or transmission direction; linked erratum is retained and requires attention before detailed quantitative reuse.", "confounders_present": [ "Shares PPMI data with other reports; proxy-defined subtypes do not identify first tissue or transmission direction; linked erratum is retained and requires attention before detailed quantitative reuse." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "PPMI longitudinal clinical/imaging/genetic source data overlap other PPMI reports." ] }, { "n": 25, "pmid": "40082617", "title": "Sympathetic and parasympathetic subtypes of body-first Lewy body disease observed in postmortem tissue from prediagnostic individuals.", "citation": "Andersen KB, Krishnamurthy A, Just MK et al. Sympathetic and parasympathetic subtypes of body-first Lewy body disease observed in postmortem tissue from prediagnostic individuals. Nature neuroscience. 2025.", "doi": "10.1038/s41593-025-01910-9", "pmcid": "PMC12081295", "url": "https://pubmed.ncbi.nlm.nih.gov/40082617/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/40082617/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID40082617", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph3, 1:Results:paragraph17, 1:Results:paragraph18, 1:Results:paragraph19, 1:Results:paragraph20, 1:Results:paragraph21, 1:Results:paragraph22. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Two postmortem datasets supported early brain-predominant and peripheral-predominant Lewy patterns; modelled body-first patterns split between vagal and sympathetic predominance.", "what_it_does_not_show": "SuStaIn orders cross-sectional scores, not observed transfer; brain-first 51 percent, parasympathetic 27 percent and sympathetic 22 percent are modelled autopsy assignments, not population gut-origin prevalence. Isolated sympathetic cases support peripheral heterogeneity; incomplete Newcastle CNS staging was crossvalidated by inference.", "confounders_present": [ "SuStaIn orders cross-sectional scores, not observed transfer; brain-first 51 percent, parasympathetic 27 percent and sympathetic 22 percent are modelled autopsy assignments, not population gut-origin prevalence. Isolated sympathetic cases support peripheral heterogeneity; incomplete Newcastle CNS staging was crossvalidated by inference." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Reanalyses BBAR and Newcastle archives; SuStaIn is a different analysis of shared specimens." ] }, { "n": 26, "pmid": "40204988", "title": "The natural history of body-first versus brain-first Parkinson's disease subtypes.", "citation": "Velucci V, Gigante AF, Iliceto G et al. The natural history of body-first versus brain-first Parkinson's disease subtypes. Journal of neurology. 2025.", "doi": "10.1007/s00415-025-13050-y", "pmcid": "PMC11982158", "url": "https://pubmed.ncbi.nlm.nih.gov/40204988/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/40204988/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID40204988", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "A prospectively followed Italian PD cohort showed greater premotor symptom burden and faster motor-stage progression in probable-premotor-RBD patients.", "what_it_does_not_show": "Retrospective symptom recall and RBD-based subtype assignment do not verify source tissue or vagal transfer; 81 of 400 proxy-positive cases do not estimate all natural gut initiation.", "confounders_present": [ "Retrospective symptom recall and RBD-based subtype assignment do not verify source tissue or vagal transfer; 81 of 400 proxy-positive cases do not estimate all natural gut initiation." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 27, "pmid": "34334424", "title": "Asymmetric Dopaminergic Dysfunction in Brain-First versus Body-First Parkinson's Disease Subtypes.", "citation": "Knudsen K, Fedorova TD, Horsager J et al. Asymmetric Dopaminergic Dysfunction in Brain-First versus Body-First Parkinson's Disease Subtypes. Journal of Parkinson's disease. 2021.", "doi": "10.3233/JPD-212761", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/34334424/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/34334424/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Danish-imaging-plus-PPMI", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "FDOPA and PPMI DaT imaging associated RBD-linked disease with more symmetric dopaminergic dysfunction.", "what_it_does_not_show": "Shares imaging and PPMI cohort components with related reports; asymmetry is compatible with route models but does not trace enteric seeds or exclude intrinsic bilateral vulnerability.", "confounders_present": [ "Shares imaging and PPMI cohort components with related reports; asymmetry is compatible with route models but does not trace enteric seeds or exclude intrinsic bilateral vulnerability." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Includes Danish imaging and PPMI components; not independent of either programme." ] }, { "n": 28, "pmid": "38860478", "title": "A Population-Based Approach to the Argument on Brain-First and Body-First Pathogenesis of Lewy Body Disease.", "citation": "Camerucci E, Mullan AF, Turcano P et al. A Population-Based Approach to the Argument on Brain-First and Body-First Pathogenesis of Lewy Body Disease. Annals of neurology. 2024.", "doi": "10.1002/ana.27006", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/38860478/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/38860478/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38860478", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "A population-based Rochester cohort did not support a stable binary body-first versus brain-first classification across alternative symptom definitions.", "what_it_does_not_show": "Definition-sensitive clinical groupings challenge simple subtype proxies rather than proving absence of peripheral initiation; PD and DLB diagnostic composition also varied.", "confounders_present": [ "Definition-sensitive clinical groupings challenge simple subtype proxies rather than proving absence of peripheral initiation; PD and DLB diagnostic composition also varied." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 29, "pmid": "42386728", "title": "Cardiac sympathetic degeneration informs the duration of the prodromal stage of body-first Lewy body disease.", "citation": "Skjærbæk C, Munk OL, Andersen KB et al. Cardiac sympathetic degeneration informs the duration of the prodromal stage of body-first Lewy body disease. NPJ Parkinson's disease. 2026.", "doi": "10.1038/s41531-026-01455-z", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/42386728/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/42386728/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID42386728", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Longitudinal cardiac and dopamine imaging across two cohorts yielded modelled sympathetic decline preceding nigrostriatal decline in putative body-first disease.", "what_it_does_not_show": "Estimated trajectories and extrapolated prodromal duration are not observed seed transfer or initial enteric pathology; autonomic denervation is a different endpoint from the proposed gut origin.", "confounders_present": [ "Estimated trajectories and extrapolated prodromal duration are not observed seed transfer or initial enteric pathology; autonomic denervation is a different endpoint from the proposed gut origin." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 30, "pmid": "30789229", "title": "Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study.", "citation": "Postuma RB, Iranzo A, Hu M et al. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study. Brain : a journal of neurology. 2019.", "doi": "10.1093/brain/awz030", "pmcid": "PMC6391615", "url": "https://pubmed.ncbi.nlm.nih.gov/30789229/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/30789229/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID30789229", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "A 24-centre prospective iRBD cohort documented frequent later parkinsonism or dementia and identified constipation and autonomic markers among predictors.", "what_it_does_not_show": "RBD already reflects central dysfunction; predictive symptoms do not identify gut origin, and conversion included several synucleinopathies rather than solely sporadic PD.", "confounders_present": [ "RBD already reflects central dysfunction; predictive symptoms do not identify gut origin, and conversion included several synucleinopathies rather than solely sporadic PD." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 31, "pmid": "34631951", "title": "Braak's Unfinished Hypothesis: A Clinicopathological Case Report of α-Synuclein Peripheral Neuropathy Preceding Parkinsonism by 20 Years.", "citation": "Donlon E, Lynch R, Murphy OC et al. Braak's Unfinished Hypothesis: A Clinicopathological Case Report of α-Synuclein Peripheral Neuropathy Preceding Parkinsonism by 20 Years. Movement disorders clinical practice. 2021.", "doi": "10.1002/mdc3.13321", "pmcid": "PMC8485622", "url": "https://pubmed.ncbi.nlm.nih.gov/34631951/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/34631951/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID34631951", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "A clinicopathological case documented peripheral sensory neuropathy and archived sural alpha-synuclein staining before overt parkinsonism and DLB.", "what_it_does_not_show": "One retrospective non-enteric case without preclinical CNS testing cannot establish common PD initiation or transport direction.", "confounders_present": [ "One retrospective non-enteric case without preclinical CNS testing cannot establish common PD initiation or transport direction." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 32, "pmid": "29032895", "title": "Cardiac sympathetic denervation predicts PD in at-risk individuals.", "citation": "Goldstein DS, Holmes C, Lopez GJ et al. Cardiac sympathetic denervation predicts PD in at-risk individuals. Parkinsonism & related disorders. 2018.", "doi": "10.1016/j.parkreldis.2017.10.003", "pmcid": "PMC6319357", "url": "https://pubmed.ncbi.nlm.nih.gov/29032895/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/29032895/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID29032895", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "In a small at-risk prospective cohort, all four subjects diagnosed with PD over three years had antecedent cardiac sympathetic denervation.", "what_it_does_not_show": "Small enriched risk sample and cardiac functional rather than enteric seed measurement cannot locate initiation or exclude earlier CNS disease.", "confounders_present": [ "Small enriched risk sample and cardiac functional rather than enteric seed measurement cannot locate initiation or exclude earlier CNS disease." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 33, "pmid": "31255487", "title": "Transneuronal Propagation of Pathologic α-Synuclein from the Gut to the Brain Models Parkinson's Disease.", "citation": "Kim S, Kwon SH, Kam TI et al. Transneuronal Propagation of Pathologic α-Synuclein from the Gut to the Brain Models Parkinson's Disease. Neuron. 2019.", "doi": "10.1016/j.neuron.2019.05.035", "pmcid": "PMC6706297", "url": "https://pubmed.ncbi.nlm.nih.gov/31255487/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/31255487/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID31255487", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Duodenal and pyloric preformed-fibril injection produced ordered brain pathology, dopamine-neuron loss and behavioural deficits; truncal vagotomy and Snca deficiency prevented these outcomes.", "what_it_does_not_show": "Exogenous seed injection supplies the proposed initiating event; route necessity within this model does not prove spontaneous human gut initiation or its prevalence.", "confounders_present": [ "Exogenous seed injection supplies the proposed initiating event; route necessity within this model does not prove spontaneous human gut initiation or its prevalence." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 34, "pmid": "25296989", "title": "Direct evidence of Parkinson pathology spread from the gastrointestinal tract to the brain in rats.", "citation": "Holmqvist S, Chutna O, Bousset L et al. Direct evidence of Parkinson pathology spread from the gastrointestinal tract to the brain in rats. Acta neuropathologica. 2014.", "doi": "10.1007/s00401-014-1343-6", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/25296989/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/25296989/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID25296989", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Intestinal-wall injection of patient brain lysate or recombinant alpha-synuclein produced time-dependent vagal transport to the rat dorsal motor nucleus; cell imaging supported axonal transport.", "what_it_does_not_show": "Forced inoculation and detectable transport are not native initiation, templated amplification at every relay or demonstrated human nigrostriatal disease.", "confounders_present": [ "Forced inoculation and detectable transport are not native initiation, templated amplification at every relay or demonstrated human nigrostriatal disease." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 35, "pmid": "29751824", "title": "Inoculation of α-synuclein preformed fibrils into the mouse gastrointestinal tract induces Lewy body-like aggregates in the brainstem via the vagus nerve.", "citation": "Uemura N, Yagi H, Uemura MT et al. Inoculation of α-synuclein preformed fibrils into the mouse gastrointestinal tract induces Lewy body-like aggregates in the brainstem via the vagus nerve. Molecular neurodegeneration. 2018.", "doi": "10.1186/s13024-018-0257-5", "pmcid": "PMC5948849", "url": "https://pubmed.ncbi.nlm.nih.gov/29751824/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/29751824/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "ErratumIn: PMID31349849" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID29751824", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "contradicts", "what_it_shows": "Gastric fibril inoculation induced vagotomy-dependent brainstem aggregates, which declined without further rostral spread through 12 months.", "what_it_does_not_show": "Supports a conduit but contradicts route sufficiency under these conditions; imposed seed dose and species may differ from natural PD, and linked correction is retained.", "confounders_present": [ "Supports a conduit but contradicts route sufficiency under these conditions; imposed seed dose and species may differ from natural PD, and linked correction is retained." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 36, "pmid": "29341898", "title": "Induction of alpha-synuclein pathology in the enteric nervous system of the rat and non-human primate results in gastrointestinal dysmotility and transient CNS pathology.", "citation": "Manfredsson FP, Luk KC, Benskey MJ et al. Induction of alpha-synuclein pathology in the enteric nervous system of the rat and non-human primate results in gastrointestinal dysmotility and transient CNS pathology. Neurobiology of disease. 2018.", "doi": "10.1016/j.nbd.2018.01.008", "pmcid": "PMC5890443", "url": "https://pubmed.ncbi.nlm.nih.gov/29341898/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/29341898/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID29341898", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "contradicts", "what_it_shows": "Enteric PFF or A53T-overexpression experiments produced gut dysfunction but only transient rodent brainstem pathology and no sustained primate CNS pathology at 12 months.", "what_it_does_not_show": "Artificial triggers and tested preparations limit extrapolation; the negative result shows context dependence rather than universal impossibility of gut-to-brain disease.", "confounders_present": [ "Artificial triggers and tested preparations limit extrapolation; the negative result shows context dependence rather than universal impossibility of gut-to-brain disease." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 37, "pmid": "31783082", "title": "Limited spread of pathology within the brainstem of α-synuclein BAC transgenic mice inoculated with preformed fibrils into the gastrointestinal tract.", "citation": "Uemura N, Yagi H, Uemura MT et al. Limited spread of pathology within the brainstem of α-synuclein BAC transgenic mice inoculated with preformed fibrils into the gastrointestinal tract. Neuroscience letters. 2020.", "doi": "10.1016/j.neulet.2019.134651", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/31783082/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/31783082/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID31783082", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "contradicts", "what_it_shows": "Even BAC A53T sensitization increased early brainstem aggregates after gut fibrils without sustained caudo-rostral spread to nigra through eight months.", "what_it_does_not_show": "Overexpression and imposed fibrils do not model endogenous origin; shares preparation and failure mode with the earlier gastric-inoculation programme.", "confounders_present": [ "Overexpression and imposed fibrils do not model endogenous origin; shares preparation and failure mode with the earlier gastric-inoculation programme." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 38, "pmid": "32066981", "title": "Gut-seeded α-synuclein fibrils promote gut dysfunction and brain pathology specifically in aged mice.", "citation": "Challis C, Hori A, Sampson TR et al. Gut-seeded α-synuclein fibrils promote gut dysfunction and brain pathology specifically in aged mice. Nature neuroscience. 2020.", "doi": "10.1038/s41593-020-0589-7", "pmcid": "PMC7065967", "url": "https://pubmed.ncbi.nlm.nih.gov/32066981/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/32066981/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID32066981", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:RESULTS:paragraph7, 1:RESULTS:paragraph8, 1:RESULTS:paragraph9. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Gut PFFs caused transient deficits in young mice and persistent deficits with reduced striatal dopamine in aged mice; aged brainstem pathology increased, but midbrain pathology increase was not significant and TH-positive counts were unchanged.", "what_it_does_not_show": "Imposed seeds and age-dependent susceptibility establish conditional capability, not the usual human initiating compartment or a universally sufficient vagal route.", "confounders_present": [ "Imposed seeds and age-dependent susceptibility establish conditional capability, not the usual human initiating compartment or a universally sufficient vagal route." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 39, "pmid": "31254094", "title": "Evidence for bidirectional and trans-synaptic parasympathetic and sympathetic propagation of alpha-synuclein in rats.", "citation": "Van Den Berge N, Ferreira N, Gram H et al. Evidence for bidirectional and trans-synaptic parasympathetic and sympathetic propagation of alpha-synuclein in rats. Acta neuropathologica. 2019.", "doi": "10.1007/s00401-019-02040-w", "pmcid": "PMC6778265", "url": "https://pubmed.ncbi.nlm.nih.gov/31254094/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/31254094/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID31254094", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Gut fibrils produced sympathetic and parasympathetic pathology and possible bidirectional dissemination in BAC rats, while wild-type rats lacked detectable propagation.", "what_it_does_not_show": "Transgenic susceptibility and artificial seeds constrain native causation; sympathetic and anterograde routes undermine an exclusive unidirectional vagal account.", "confounders_present": [ "Transgenic susceptibility and artificial seeds constrain native causation; sympathetic and anterograde routes undermine an exclusive unidirectional vagal account." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "BAC alpha-synuclein sensitization and imposed fibril preparation." ] }, { "n": 40, "pmid": "32380543", "title": "Bidirectional gut-to-brain and brain-to-gut propagation of synucleinopathy in non-human primates.", "citation": "Arotcarena ML, Dovero S, Prigent A et al. Bidirectional gut-to-brain and brain-to-gut propagation of synucleinopathy in non-human primates. Brain : a journal of neurology. 2020.", "doi": "10.1093/brain/awaa096", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/32380543/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/32380543/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "ErratumIn: PMID39873693" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID32380543", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "contradicts", "what_it_shows": "Baboon enteric or striatal patient-extract injection produced both nigrostriatal and enteric lesions, without detectable vagal lesions in the tested setting.", "what_it_does_not_show": "Imposed extracts and small primate experiments do not establish a spontaneous route; circulating transfer is a proposed explanation rather than directly traced mediation, and linked correction is retained. A 2025 publisher correction reports duplicated/misassigned representative panels; corrected images and raw data were not audited, so this is qualified rather than singular decisive evidence. A 2025 publisher correction reports duplicated/misassigned representative panels; corrected images and raw data were not audited, so this is qualified rather than singular decisive evidence.", "confounders_present": [ "Imposed extracts and small primate experiments do not establish a spontaneous route; circulating transfer is a proposed explanation rather than directly traced mediation, and linked correction is retained. A 2025 publisher correction reports duplicated/misassigned representative panels; corrected images and raw data were not audited, so this is qualified rather than singular decisive evidence. A 2025 publisher correction reports duplicated/misassigned representative panels; corrected images and raw data were not audited, so this is qualified rather than singular decisive evidence." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 41, "pmid": "33880502", "title": "Ageing promotes pathological alpha-synuclein propagation and autonomic dysfunction in wild-type rats.", "citation": "Van Den Berge N, Ferreira N, Mikkelsen TW et al. Ageing promotes pathological alpha-synuclein propagation and autonomic dysfunction in wild-type rats. Brain : a journal of neurology. 2021.", "doi": "10.1093/brain/awab061", "pmcid": "PMC8320301", "url": "https://pubmed.ncbi.nlm.nih.gov/33880502/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/33880502/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID33880502", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Gut-injected aggregates spread more extensively through autonomic pathways in aged wild-type rats, with cardiac and gastric dysfunction and more mature aggregates.", "what_it_does_not_show": "Age improves physiological relevance but initiation remains imposed; bidirectionality and sympathetic routes do not establish a solely vagal natural human origin.", "confounders_present": [ "Age improves physiological relevance but initiation remains imposed; bidirectionality and sympathetic routes do not establish a solely vagal natural human origin." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "Related autonomic propagation programme, but aged wild-type animals differ from BAC rats." ] }, { "n": 42, "pmid": "38063197", "title": "Gut mucosal cells transfer α-synuclein to the vagus nerve.", "citation": "Chandra R, Sokratian A, Chavez KR et al. Gut mucosal cells transfer α-synuclein to the vagus nerve. JCI insight. 2023.", "doi": "10.1172/jci.insight.172192", "pmcid": "PMC10795834", "url": "https://pubmed.ncbi.nlm.nih.gov/38063197/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/38063197/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "UpdateOf: PMID37645945" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38063197", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph1, 1:Results:paragraph3, 1:Results:paragraph4, 2:Discussion, 3:Methods. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Organoid coculture and epithelial-restricted human-alpha-synuclein mice supported mucosal-to-neural transfer; vagotomy prevented hindbrain templating activity after epithelial induction.", "what_it_does_not_show": "Original Methods/Results identify mixed wild-type/A30P/A53T transgenes restricted to gut mucosa and pre-induction vagotomy with about 15 percent weight loss. Modest expression and in-situ seed formation are stronger than injected fibrils, but neuronal uptake need not involve recipient templating; no nigral-loss endpoint or common human origin is established.", "confounders_present": [ "Original Methods/Results identify mixed wild-type/A30P/A53T transgenes restricted to gut mucosa and pre-induction vagotomy with about 15 percent weight loss. Modest expression and in-situ seed formation are stronger than injected fibrils, but neuronal uptake need not involve recipient templating; no nigral-loss endpoint or common human origin is established." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 43, "pmid": "28614796", "title": "α-Synuclein in gut endocrine cells and its implications for Parkinson's disease.", "citation": "Chandra R, Hiniker A, Kuo YM et al. α-Synuclein in gut endocrine cells and its implications for Parkinson's disease. JCI insight. 2017.", "doi": "10.1172/jci.insight.92295", "pmcid": "PMC5470880", "url": "https://pubmed.ncbi.nlm.nih.gov/28614796/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/28614796/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID28614796", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC2" ], "favors_models": [], "evidence_class": "Weak", "system": "human experimental", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Human and mouse enteroendocrine cells expressed alpha-synuclein and connected to alpha-synuclein-containing nerves, identifying a possible mucosal source compartment.", "what_it_does_not_show": "Expression and anatomical contact are not pathological misfolding, transfer or causal PD; the paper's premise that enteric pathology precedes brain pathology is not demonstrated by this experiment.", "confounders_present": [ "Expression and anatomical contact are not pathological misfolding, transfer or causal PD; the paper's premise that enteric pathology precedes brain pathology is not demonstrated by this experiment." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 44, "pmid": "35264710", "title": "Transcellular propagation of fibrillar α-synuclein from enteroendocrine to neuronal cells requires cell-to-cell contact and is Rab35-dependent.", "citation": "Rodrigues PV, de Godoy JVP, Bosque BP et al. Transcellular propagation of fibrillar α-synuclein from enteroendocrine to neuronal cells requires cell-to-cell contact and is Rab35-dependent. Scientific reports. 2022.", "doi": "10.1038/s41598-022-08076-5", "pmcid": "PMC8907230", "url": "https://pubmed.ncbi.nlm.nih.gov/35264710/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/35264710/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID35264710", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "human experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Seeded enteroendocrine-to-neuronal cell propagation required physical contact and Rab35, with enhanced lysosomal clearance after inhibition.", "what_it_does_not_show": "Cell lines and added fibrils test a transfer mechanism rather than endogenous whole-animal or human gut initiation and degeneration.", "confounders_present": [ "Cell lines and added fibrils test a transfer mechanism rather than endogenous whole-animal or human gut initiation and degeneration." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 45, "pmid": "33895878", "title": "Transmissible α-synuclein seeding activity in brain and stomach of patients with Parkinson's disease.", "citation": "Thomzig A, Wagenführ K, Pinder P et al. Transmissible α-synuclein seeding activity in brain and stomach of patients with Parkinson's disease. Acta neuropathologica. 2021.", "doi": "10.1007/s00401-021-02312-4", "pmcid": "PMC8068459", "url": "https://pubmed.ncbi.nlm.nih.gov/33895878/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/33895878/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "ErratumIn: PMID33956225" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID33895878", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Intracerebral transmission of human stomach or brain homogenate produced localized aggregation in sensitized mice, unlike blood or muscle, without overt motor disease.", "what_it_does_not_show": "Imposed intracerebral delivery bypasses vagal transport; subtle aggregation after long incubation is not PD neurodegeneration or a native enteric origin, and linked erratum is retained. The correction changes stomach-homogenate pathology denominators including 7/7 to 7/14; no uncorrected rate is used. The correction changes stomach-homogenate pathology denominators including 7/7 to 7/14; no uncorrected rate is used.", "confounders_present": [ "Imposed intracerebral delivery bypasses vagal transport; subtle aggregation after long incubation is not PD neurodegeneration or a native enteric origin, and linked erratum is retained. The correction changes stomach-homogenate pathology denominators including 7/7 to 7/14; no uncorrected rate is used. The correction changes stomach-homogenate pathology denominators including 7/7 to 7/14; no uncorrected rate is used." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 46, "pmid": "33445653", "title": "Seeding Propensity and Characteristics of Pathogenic αSyn Assemblies in Formalin-Fixed Human Tissue from the Enteric Nervous System, Olfactory Bulb, and Brainstem in Cases Staged for Parkinson's Disease.", "citation": "Fenyi A, Duyckaerts C, Bousset L et al. Seeding Propensity and Characteristics of Pathogenic αSyn Assemblies in Formalin-Fixed Human Tissue from the Enteric Nervous System, Olfactory Bulb, and Brainstem in Cases Staged for Parkinson's Disease. Cells. 2021.", "doi": "10.3390/cells10010139", "pmcid": "PMC7828121", "url": "https://pubmed.ncbi.nlm.nih.gov/33445653/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/33445653/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID33445653", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC2" ], "favors_models": [], "evidence_class": "Weak", "system": "human experimental", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Amplification assays detected seeding from fixed gastric and brain tissues and regionally different assemblies, without a consistent region-specific seeding gradient.", "what_it_does_not_show": "Formalin and in-vitro amplification can alter detectable seed properties; postmortem tissue and strain differences cannot determine temporal or transport direction.", "confounders_present": [ "Formalin and in-vitro amplification can alter detectable seed properties; postmortem tissue and strain differences cannot determine temporal or transport direction." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 47, "pmid": "31649329", "title": "Initiation of Parkinson's disease from gut to brain by δ-secretase.", "citation": "Ahn EH, Kang SS, Liu X et al. Initiation of Parkinson's disease from gut to brain by δ-secretase. Cell research. 2020.", "doi": "10.1038/s41422-019-0241-9", "pmcid": "PMC6951265", "url": "https://pubmed.ncbi.nlm.nih.gov/31649329/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/31649329/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID31649329", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Rotenone and fragment-fibril experiments implicated AEP-dependent alpha-synuclein and tau cleavage in enteric and nigral pathology.", "what_it_does_not_show": "Systemic neurotoxin effects and forced fragment seeds do not isolate a natural enteric starting site; dependence on AEP does not alone establish vagal mediation in sporadic humans.", "confounders_present": [ "Systemic neurotoxin effects and forced fragment seeds do not isolate a natural enteric starting site; dependence on AEP does not alone establish vagal mediation in sporadic humans." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "C/EBPbeta/AEP/rotenone programme overlaps mechanistic premises with related reports." ] }, { "n": 48, "pmid": "32911010", "title": "BDNF and Netrin-1 repression by C/EBPβ in the gut triggers Parkinson's disease pathologies, associated with constipation and motor dysfunctions.", "citation": "Ahn EH, Kang SS, Liu X et al. BDNF and Netrin-1 repression by C/EBPβ in the gut triggers Parkinson's disease pathologies, associated with constipation and motor dysfunctions. Progress in neurobiology. 2021.", "doi": "10.1016/j.pneurobio.2020.101905", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/32911010/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/32911010/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID32911010", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Strong", "system": "animal experimental", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "Gut conditional loss of trophic factors produced constipation, dopaminergic loss and motor abnormalities, while human tissue correlations and rotenone models implicated C/EBPbeta.", "what_it_does_not_show": "A targeted endogenous trophic perturbation supports gut influence on degeneration; it does not by itself identify alpha-synuclein transfer as the necessary mediator or quantify spontaneous human gut initiation.", "confounders_present": [ "A targeted endogenous trophic perturbation supports gut influence on degeneration; it does not by itself identify alpha-synuclein transfer as the necessary mediator or quantify spontaneous human gut initiation." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 49, "pmid": "36609384", "title": "C/EBPβ/AEP is age-dependently activated in Parkinson's disease and mediates α-synuclein in the gut and brain.", "citation": "Wang H, Chen G, Ahn EH et al. C/EBPβ/AEP is age-dependently activated in Parkinson's disease and mediates α-synuclein in the gut and brain. NPJ Parkinson's disease. 2023.", "doi": "10.1038/s41531-022-00430-8", "pmcid": "PMC9822984", "url": "https://pubmed.ncbi.nlm.nih.gov/36609384/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/36609384/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID36609384", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "C/EBPbeta or AEP deletion reduced age- and rotenone-associated pathology and motor deficits in human-SNCA transgenic mice with apparent gut-to-brain progression.", "what_it_does_not_show": "Human-protein transgenesis, global pathway effects and toxin exposure complicate origin-specific mediation; related reports share pathway and laboratory components.", "confounders_present": [ "Human-protein transgenesis, global pathway effects and toxin exposure complicate origin-specific mediation; related reports share pathway and laboratory components." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [ "C/EBPbeta/AEP/rotenone programme; distinct readouts are not fully independent causal lines." ] }, { "n": 50, "pmid": "31079293", "title": "Chronic Mild Gut Inflammation Accelerates Brain Neuropathology and Motor Dysfunction in α-Synuclein Mutant Mice.", "citation": "Kishimoto Y, Zhu W, Hosoda W et al. Chronic Mild Gut Inflammation Accelerates Brain Neuropathology and Motor Dysfunction in α-Synuclein Mutant Mice. Neuromolecular medicine. 2019.", "doi": "10.1007/s12017-019-08539-5", "pmcid": "PMC6701950", "url": "https://pubmed.ncbi.nlm.nih.gov/31079293/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/31079293/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID31079293", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Mild chronic DSS gut inflammation accelerated motor dysfunction and nigral marker loss in alpha-synuclein-mutant mice with increased enteric and brain pathology.", "what_it_does_not_show": "Genetic sensitization and inflammatory perturbation do not isolate vagal alpha-synuclein transfer from immune or systemic influences; acceleration is not proof of initial human cause.", "confounders_present": [ "Genetic sensitization and inflammatory perturbation do not isolate vagal alpha-synuclein transfer from immune or systemic influences; acceleration is not proof of initial human cause." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 51, "pmid": "27912057", "title": "Gut Microbiota Regulate Motor Deficits and Neuroinflammation in a Model of Parkinson's Disease.", "citation": "Sampson TR, Debelius JW, Thron T et al. Gut Microbiota Regulate Motor Deficits and Neuroinflammation in a Model of Parkinson's Disease. Cell. 2016.", "doi": "10.1016/j.cell.2016.11.018", "pmcid": "PMC5718049", "url": "https://pubmed.ncbi.nlm.nih.gov/27912057/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27912057/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27912057", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Microbiota depletion, recolonization, metabolites and patient-donor transfer modulated motor deficits and neuroinflammation in alpha-synuclein-overexpressing mice.", "what_it_does_not_show": "Overexpression and microbiome manipulation support a gut modifier; they do not establish enteric seeds ascending the vagus, and germ-free developmental and donor effects limit transfer.", "confounders_present": [ "Overexpression and microbiome manipulation support a gut modifier; they do not establish enteric seeds ascending the vagus, and germ-free developmental and donor effects limit transfer." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 52, "pmid": "39449004", "title": "Gut-first Parkinson's disease is encoded by gut dysbiome.", "citation": "Munoz-Pinto MF, Candeias E, Melo-Marques I et al. Gut-first Parkinson's disease is encoded by gut dysbiome. Molecular neurodegeneration. 2024.", "doi": "10.1186/s13024-024-00766-0", "pmcid": "PMC11515425", "url": "https://pubmed.ncbi.nlm.nih.gov/39449004/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/39449004/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID39449004", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Strong", "system": "animal experimental", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "PD-donor microbiota transferred into wild-type mice produced TH-positive cell loss, motor impairment and gut-immune-brain changes.", "what_it_does_not_show": "Donor medications, recipient conditioning and systemic immune or barrier routes require separation from vagal transfer; TH-positive counts need corroboration of neuron survival before equating them to complete neuronal death.", "confounders_present": [ "Donor medications, recipient conditioning and systemic immune or barrier routes require separation from vagal transfer; TH-positive counts need corroboration of neuron survival before equating them to complete neuronal death." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 53, "pmid": "41207395", "title": "Early alpha-synuclein accumulation, oxidative stress and inflammation in the proximal colon of c-rel-/- mouse model of Parkinson's disease.", "citation": "Parrella E, Gennari MM, Abate G et al. Early alpha-synuclein accumulation, oxidative stress and inflammation in the proximal colon of c-rel-/- mouse model of Parkinson's disease. Neurobiology of disease. 2025.", "doi": "10.1016/j.nbd.2025.107182", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/41207395/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/41207395/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID41207395", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC2" ], "favors_models": [], "evidence_class": "Strong", "system": "animal experimental", "decisive_perturbation": false, "endogenous": true, "direction": "supports", "what_it_shows": "Endogenous global c-rel knockout mice showed early proximal-colon alpha-synuclein accumulation with later oxidative stress, inflammation and enteric TH-positive loss.", "what_it_does_not_show": "Global genotype can affect gut and brain in parallel; the reported colon time course does not prove transfer necessity or exclude an independently initiating CNS defect.", "confounders_present": [ "Global genotype can affect gut and brain in parallel; the reported colon time course does not prove transfer necessity or exclude an independently initiating CNS defect." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 54, "pmid": "40187668", "title": "Gut microbiota promote the propagation of pathologic α-syn from gut to brain in a gut-originated mouse model of Parkinson's disease.", "citation": "Wu J, Li CS, Huang WY et al. Gut microbiota promote the propagation of pathologic α-syn from gut to brain in a gut-originated mouse model of Parkinson's disease. Brain, behavior, and immunity. 2025.", "doi": "10.1016/j.bbi.2025.04.001", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/40187668/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/40187668/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID40187668", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Antibiotics reduced progression in a gut-originated model; bacterial and metabolite experiments implicated BCAA-related impaired microglial alpha-synuclein clearance.", "what_it_does_not_show": "The abstract does not specify how the initiating mouse model was generated; route dependence and primary origin cannot be assumed, and antibiotic effects extend beyond the identified metabolite.", "confounders_present": [ "The abstract does not specify how the initiating mouse model was generated; route dependence and primary origin cannot be assumed, and antibiotic effects extend beyond the identified metabolite." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 55, "pmid": "41808195", "title": "Gut-initiated alpha synuclein fibrils drive parkinsonism phenotypes: temporal mapping of REM sleep behavior disorder-like and other non-motor symptoms.", "citation": "Dautan D, Paslawski W, Montejo SG et al. Gut-initiated alpha synuclein fibrils drive parkinsonism phenotypes: temporal mapping of REM sleep behavior disorder-like and other non-motor symptoms. Translational neurodegeneration. 2026.", "doi": "10.1186/s40035-026-00536-6", "pmcid": "PMC12973632", "url": "https://pubmed.ncbi.nlm.nih.gov/41808195/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/41808195/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "UpdateOf: PMID38712208" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID41808195", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Gut PFF injection in wild-type mice produced temporally mapped central spread and motor and sleep phenotypes, with central dopamine experiments linking REM abnormalities to nigral dysfunction.", "what_it_does_not_show": "Exogenous seeds impose the initiating lesion; RBD-like animal behaviours do not establish a human gut-first subtype, and the final report replaces its preprint.", "confounders_present": [ "Exogenous seeds impose the initiating lesion; RBD-like animal behaviours do not establish a human gut-first subtype, and the final report replaces its preprint." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 56, "pmid": "40913049", "title": "Gut microbial production of imidazole propionate drives Parkinson's pathologies.", "citation": "Park H, Cheon J, Kim H et al. Gut microbial production of imidazole propionate drives Parkinson's pathologies. Nature communications. 2025.", "doi": "10.1038/s41467-025-63473-4", "pmcid": "PMC12413466", "url": "https://pubmed.ncbi.nlm.nih.gov/40913049/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/40913049/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID40913049", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph3, 1:Results:paragraph5, 1:Results:paragraph9, 1:Results:paragraph13, 1:Results:paragraph14, 1:Results:paragraph16, 1:Results:paragraph17. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Strong", "system": "animal experimental", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "Microbial UrdA and imidazole propionate manipulations increased brain metabolite exposure and PD-like neuronal and behavioural outcomes, with mTORC1 implicated.", "what_it_does_not_show": "Original Results include Nissl/TH stereology, matched bacterial colonization and rapamycin protection without lowering ImP exposure. Germ-free or antibiotic conditioning and administered metabolites constrain transfer; the human plasma comparison follows a mean 9.5 years of PD and cannot establish initiation.", "confounders_present": [ "Original Results include Nissl/TH stereology, matched bacterial colonization and rapamycin protection without lowering ImP exposure. Germ-free or antibiotic conditioning and administered metabolites constrain transfer; the human plasma comparison follows a mean 9.5 years of PD and cannot establish initiation." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 57, "pmid": "38750146", "title": "Sex-dependent interactions between prodromal intestinal inflammation and LRRK2 G2019S in mice promote endophenotypes of Parkinson's disease.", "citation": "Fang P, Yu LW, Espey H et al. Sex-dependent interactions between prodromal intestinal inflammation and LRRK2 G2019S in mice promote endophenotypes of Parkinson's disease. Communications biology. 2024.", "doi": "10.1038/s42003-024-06256-9", "pmcid": "PMC11096388", "url": "https://pubmed.ncbi.nlm.nih.gov/38750146/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/38750146/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38750146", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Intestinal inflammation accelerated nigral aggregation and dopaminergic loss in male human-LRRK2-G2019S mice, with sex-chromosome manipulations retaining male susceptibility.", "what_it_does_not_show": "A familial-risk genotype and induced colitis support conditional gut influence; myeloid transport, inflammatory signalling and direct vagal transfer remain distinct possibilities.", "confounders_present": [ "A familial-risk genotype and induced colitis support conditional gut influence; myeloid transport, inflammatory signalling and direct vagal transfer remain distinct possibilities." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 58, "pmid": "30554160", "title": "Role of TLR4 in the gut-brain axis in Parkinson's disease: a translational study from men to mice.", "citation": "Perez-Pardo P, Dodiya HB, Engen PA et al. Role of TLR4 in the gut-brain axis in Parkinson's disease: a translational study from men to mice. Gut. 2019.", "doi": "10.1136/gutjnl-2018-316844", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/30554160/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/30554160/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID30554160", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Moderate", "system": "animal experimental", "decisive_perturbation": true, "endogenous": false, "direction": "supports", "what_it_shows": "Human colon inflammation was accompanied by rotenone-model protection after TLR4 knockout despite persistent dysbiosis.", "what_it_does_not_show": "Global receptor deletion and neurotoxin exposure do not isolate gut-to-vagus seeds; human cross-sectional inflammation could follow disease, transit or medication changes.", "confounders_present": [ "Global receptor deletion and neurotoxin exposure do not isolate gut-to-vagus seeds; human cross-sectional inflammation could follow disease, transit or medication changes." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 59, "pmid": "34412704", "title": "Experimental colitis promotes sustained, sex-dependent, T-cell-associated neuroinflammation and parkinsonian neuropathology.", "citation": "Houser MC, Caudle WM, Chang J et al. Experimental colitis promotes sustained, sex-dependent, T-cell-associated neuroinflammation and parkinsonian neuropathology. Acta neuropathologica communications. 2021.", "doi": "10.1186/s40478-021-01240-4", "pmcid": "PMC8375080", "url": "https://pubmed.ncbi.nlm.nih.gov/34412704/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/34412704/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID34412704", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2" ], "favors_models": [], "evidence_class": "Strong", "system": "animal experimental", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "Colitis induced sustained TH-marker reduction and neuroinflammation in male mice; CD8 depletion prevented the TH change, and colitis increased later MPTP vulnerability.", "what_it_does_not_show": "Dopamine itself was not reduced after colitis; immune effects and neurotoxin susceptibility are not proven neuron death or alpha-synuclein vagal transfer, providing an alternative gut-brain mediator.", "confounders_present": [ "Dopamine itself was not reduced after colitis; immune effects and neurotoxin susceptibility are not proven neuron death or alpha-synuclein vagal transfer, providing an alternative gut-brain mediator." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 60, "pmid": "37130861", "title": "Gut microbiome dysbiosis across early Parkinson's disease, REM sleep behavior disorder and their first-degree relatives.", "citation": "Huang B, Chau SWH, Liu Y et al. Gut microbiome dysbiosis across early Parkinson's disease, REM sleep behavior disorder and their first-degree relatives. Nature communications. 2023.", "doi": "10.1038/s41467-023-38248-4", "pmcid": "PMC10154387", "url": "https://pubmed.ncbi.nlm.nih.gov/37130861/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/37130861/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID37130861", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "Cross-sectional early-PD, RBD and relatives showed dysbiosis including depleted butyrate-producing bacteria after adjustment for several transit and medication variables.", "what_it_does_not_show": "RBD and family-enriched associations do not establish direction, first seed tissue or transmission; residual diet and shared-environment confounding remain.", "confounders_present": [ "RBD and family-enriched associations do not establish direction, first seed tissue or transmission; residual diet and shared-environment confounding remain." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 61, "pmid": "39218360", "title": "Difference in gut microbial dysbiotic patterns between body-first and brain-first Parkinson's disease.", "citation": "Park DG, Kang W, Shin IJ et al. Difference in gut microbial dysbiotic patterns between body-first and brain-first Parkinson's disease. Neurobiology of disease. 2024.", "doi": "10.1016/j.nbd.2024.106655", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/39218360/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/39218360/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID39218360", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Weak", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "supports", "what_it_shows": "A small subtype-classified metagenomic study found different microbial and curli-related gene profiles in body-first proxy groups.", "what_it_does_not_show": "Cross-sectional 15-versus-nine subgroup comparisons, transit and treatment can explain microbiome patterns; inferred microbial functions are not measured human seed transfer.", "confounders_present": [ "Cross-sectional 15-versus-nine subgroup comparisons, transit and treatment can explain microbiome patterns; inferred microbial functions are not measured human seed transfer." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 62, "pmid": "41350593", "title": "Supplementation with short-chain fatty acids and a prebiotic improves clinical outcome in Parkinson's disease: a randomized double-blind prospective study.", "citation": "Hegelmaier T, Duscha A, Desel C et al. Supplementation with short-chain fatty acids and a prebiotic improves clinical outcome in Parkinson's disease: a randomized double-blind prospective study. Scientific reports. 2025.", "doi": "10.1038/s41598-025-29692-x", "pmcid": "PMC12770440", "url": "https://pubmed.ncbi.nlm.nih.gov/41350593/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/41350593/", "tier": "A", "source_tier": "A", "kind": "rct", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID41350593", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human interventional", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "A randomized double-blind supplementation report described motor and medication changes over six months alongside immune and barrier outcomes.", "what_it_does_not_show": "The abstract does not establish an inactive comparator or enteric-seed/vagal mediator; retrospective registration, concurrent PD therapy and symptom change cannot prove disease modification or primary origin.", "confounders_present": [ "The abstract does not establish an inactive comparator or enteric-seed/vagal mediator; retrospective registration, concurrent PD therapy and symptom change cannot prove disease modification or primary origin." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 63, "pmid": "22941241", "title": "Parkinson's disease is not associated with gastrointestinal myenteric ganglion neuron loss.", "citation": "Annerino DM, Arshad S, Taylor GM et al. Parkinson's disease is not associated with gastrointestinal myenteric ganglion neuron loss. Acta neuropathologica. 2012.", "doi": "10.1007/s00401-012-1040-2", "pmcid": "PMC3473167", "url": "https://pubmed.ncbi.nlm.nih.gov/22941241/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/22941241/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID22941241", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "Quantitative gastrointestinal autopsy comparison found preserved myenteric neuron density despite enteric Lewy pathology, whose distribution followed parasympathetic input.", "what_it_does_not_show": "End-stage density and staining do not exclude prior functional injury or origin; the result challenges attributing gut dysfunction directly to enteric neuron loss.", "confounders_present": [ "End-stage density and staining do not exclude prior functional injury or origin; the result challenges attributing gut dysfunction directly to enteric neuron loss." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 64, "pmid": "27621223", "title": "Appendectomy and risk of Parkinson's disease: A nationwide cohort study with more than 10 years of follow-up.", "citation": "Svensson E, Horváth-Puhó E, Stokholm MG et al. Appendectomy and risk of Parkinson's disease: A nationwide cohort study with more than 10 years of follow-up. Movement disorders : official journal of the Movement Disorder Society. 2016.", "doi": "10.1002/mds.26761", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/27621223/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27621223/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27621223", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "contradicts", "what_it_shows": "A large Danish matched registry study found a small increased rather than decreased PD hazard at least ten years after appendectomy, persisting after longer follow-up.", "what_it_does_not_show": "Nonrandom surgery and inflammation-related indications remain confounders; contradicts a simple universal appendix-reservoir protection prediction without excluding a subset effect.", "confounders_present": [ "Nonrandom surgery and inflammation-related indications remain confounders; contradicts a simple universal appendix-reservoir protection prediction without excluding a subset effect." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 65, "pmid": "30218460", "title": "Appendectomy and risk of Parkinson's disease in two large prospective cohorts of men and women.", "citation": "Palacios N, Hughes KC, Cereda E et al. Appendectomy and risk of Parkinson's disease in two large prospective cohorts of men and women. Movement disorders : official journal of the Movement Disorder Society. 2018.", "doi": "10.1002/mds.109", "pmcid": "PMC6310901", "url": "https://pubmed.ncbi.nlm.nih.gov/30218460/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/30218460/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID30218460", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "contradicts", "what_it_shows": "Prospective Nurses' Health and Health Professionals cohorts found no overall reduced PD hazard after self-reported appendectomy, with higher risk for appendicitis-related surgery in women.", "what_it_does_not_show": "Exposure recall and operative indication affect inference; results oppose simple reservoir-removal protection but do not test vagal transfer directly.", "confounders_present": [ "Exposure recall and operative indication affect inference; results oppose simple reservoir-removal protection but do not test vagal transfer directly." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 66, "pmid": "27241338", "title": "Appendectomy in mid and later life and risk of Parkinson's disease: A population-based study.", "citation": "Marras C, Lang AE, Austin PC et al. Appendectomy in mid and later life and risk of Parkinson's disease: A population-based study. Movement disorders : official journal of the Movement Disorder Society. 2016.", "doi": "10.1002/mds.26670", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/27241338/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/27241338/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27241338", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "contradicts", "what_it_shows": "Appendectomy after age 35 did not reduce later PD risk relative to cholecystectomy, and the early increase relative to no surgery disappeared with longer follow-up.", "what_it_does_not_show": "Midlife surgery may miss an earlier initiation window; comparator procedures and indication confounding leave subtype-specific effects unresolved.", "confounders_present": [ "Midlife surgery may miss an earlier initiation window; comparator procedures and indication confounding leave subtype-specific effects unresolved." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 67, "pmid": "38696328", "title": "Appendectomy and the Risk of Parkinson's Disease: A Korean Nationwide Study.", "citation": "Park KW, Woo HT, Hwang YS et al. Appendectomy and the Risk of Parkinson's Disease: A Korean Nationwide Study. Movement disorders clinical practice. 2024.", "doi": "10.1002/mdc3.14031", "pmcid": "PMC11145134", "url": "https://pubmed.ncbi.nlm.nih.gov/38696328/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/38696328/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38696328", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "null", "what_it_shows": "A Korean national cohort found no statistically resolved appendectomy-PD association, with adjusted hazard confidence limits spanning protection and increased risk.", "what_it_does_not_show": "Imprecision and nonrandom surgery preclude interpreting a null test as equivalence or excluding an earlier subtype-specific reservoir.", "confounders_present": [ "Imprecision and nonrandom surgery preclude interpreting a null test as equivalence or excluding an earlier subtype-specific reservoir." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 68, "pmid": "32595591", "title": "Appendectomy, Tonsillectomy and Parkinson's Disease Risk: A Swedish Register-Based Study.", "citation": "Liu B, Fang F, Ye W et al. Appendectomy, Tonsillectomy and Parkinson's Disease Risk: A Swedish Register-Based Study. Frontiers in neurology. 2020.", "doi": "10.3389/fneur.2020.00510", "pmcid": "PMC7292857", "url": "https://pubmed.ncbi.nlm.nih.gov/32595591/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/32595591/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Swedish-register-overlapping-source", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC2", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "natural experiment", "decisive_perturbation": true, "endogenous": true, "direction": "supports", "what_it_shows": "A Swedish nested case-control study associated prior appendectomy with lower PD odds, including long lags, with a less precise tonsillectomy association.", "what_it_does_not_show": "Overlaps national register source populations with earlier Swedish studies; surgical indications, smoking proxies and hospital-use ascertainment do not isolate alpha-synuclein reservoir removal.", "confounders_present": [ "Overlaps national register source populations with earlier Swedish studies; surgical indications, smoking proxies and hospital-use ascertainment do not isolate alpha-synuclein reservoir removal." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] }, { "n": 69, "pmid": "18053026", "title": "The dorsal motor nucleus of the vagus is not an obligatory trigger site of Parkinson's disease: a critical analysis of alpha-synuclein staging.", "citation": "Kalaitzakis ME, Graeber MB, Gentleman SM et al. The dorsal motor nucleus of the vagus is not an obligatory trigger site of Parkinson's disease: a critical analysis of alpha-synuclein staging. Neuropathology and applied neurobiology. 2008.", "doi": "10.1111/j.1365-2990.2007.00923.x", "pmcid": "", "url": "https://pubmed.ncbi.nlm.nih.gov/18053026/", "source_pointer": "https://pubmed.ncbi.nlm.nih.gov/18053026/", "tier": "A", "source_tier": "A", "kind": "primary", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID18053026", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "relates_to_subclaims": [ "SC1", "SC3" ], "favors_models": [], "evidence_class": "Moderate", "system": "human observational", "decisive_perturbation": false, "endogenous": false, "direction": "contradicts", "what_it_shows": "Seventy-one PD brains included widespread noncanonical staging and cases without DMV involvement despite nigral or cortical pathology.", "what_it_does_not_show": "Autopsy sampling and lesion clearance limit temporal inference; shows the DMV is not universally obligatory, without quantifying how often gut-vagal origin occurs.", "confounders_present": [ "Autopsy sampling and lesion clearance limit temporal inference; shows the DMV is not universally obligatory, without quantifying how often gut-vagal origin occurs." ], "verification": "verified", "verification_note": "Bounded source attribution; not proof of the nominal mechanism.", "citation_context": { "retrieved": false, "supporting_count": 0, "mentioning_count": 0, "contrasting_count": 0, "notable_contrasting_statements": [] }, "shared_components": [] } ], "verification_summary": { "load_bearing_claims_checked": 73, "verified": 73, "unverified": 0, "contradicted": 0, "note": "Verified attribution is distinct from mechanism truth or complete body access." }, "factual_issues_found": [], "cap_rules_applied": [], "cap_precedence_resolutions": [ { "collision": "Perturbation in a defined setting versus broader inference", "subclaim_scope_cap_binds_on": "Sporadic Parkinson disease commonly begins with enteric alpha-synuclein pathology that ascends through vagal connections to the CNS and drives nigrostriatal neurodegeneration.", "subclaim_scope_threshold_binds_on": "The precise experimentally tested subclaim scope", "resolution": "The neurodegeneration rubric admits vagotomy-type natural experiments only with rigorous confounder control and disease-initiation relevance. These cohorts are considered as field-valid candidates, not rejected because they are nonrandomized; residual indication/smoking/era and mediator uncertainty prevent the registered initiation inference. PFF blockade and engineered gut-expression tests establish restricted route capability. Native trophic and immune perturbations carry real causal weight for alternative gut influences. No literal Gamma cap is claimed over the convergent whole; all three registered gates stop on unmet positive scope burdens.", "note": "Convergent lines are assessed as a set; one weak leg is not re-capped over the assembled case." } ], "boundary_check_BGD": [ { "subclaim_id": "SC1", "field_valid_perturbation_quote": "\n- Endogenous genetic deletion, suppression, or degron depletion of the proposed mediator in vivo\n- Selective pathway inhibition that changes onset/progression while preserving broader viability\n- Vagotomy-type natural experiment, only if confounding is rigorously controlled AND effect is disease-initiation relevant rather than merely associated", "qualifying_evidence_present": "no", "qualifying_evidence_citation": "PMID30381408", "gamma_hard_rules_triggered": [ "Temporal order before CNS disease is unresolved." ], "disease_phenotype_relevance": "yes", "perturbation_result_positive": "no", "perturbation_result_note": "Premotor enteric pathology and autonomic dysfunction are reproducible in selected groups, but motor diagnosis is not the onset of CNS pathology. Serial paired gut and central seed measurements establishing enteric-before-CNS order are absent from the examined causal case; sampled autopsies provide contrary patterns.", "ceiling_from_boundary_check": "Γ" }, { "subclaim_id": "SC2", "field_valid_perturbation_quote": "\n- Endogenous genetic deletion, suppression, or degron depletion of the proposed mediator in vivo\n- Selective pathway inhibition that changes onset/progression while preserving broader viability\n- Vagotomy-type natural experiment, only if confounding is rigorously controlled AND effect is disease-initiation relevant rather than merely associated", "qualifying_evidence_present": "no", "qualifying_evidence_citation": "PMID29422109, PMID26031848, PMID28446653, PMID30381408, PMID31255487, PMID25296989, PMID29751824, PMID29341898, PMID31783082, PMID32066981, PMID31254094, PMID32380543, PMID33880502, PMID38063197, PMID35264710, PMID33895878, PMID31649329, PMID32911010, PMID36609384, PMID31079293, PMID27912057, PMID39449004, PMID40187668, PMID41808195, PMID40913049, PMID38750146, PMID30554160, PMID34412704, PMID41350593, PMID27621223, PMID30218460, PMID27241338, PMID38696328, PMID32595591", "gamma_hard_rules_triggered": [ "Human route necessity remains unresolved despite conditional model transmission." ], "disease_phenotype_relevance": "yes", "perturbation_result_positive": "no", "perturbation_result_note": "Vagal continuity is causally relevant in imposed-seed and engineered gut-mucosal systems. The latter generates seeds in situ and is credited beyond injected fibrils, yet uses human transgenes and does not establish nigral loss. Registry vagotomy is suggestive but not a rigorously isolated natural-origin instrument; the native human disease route remains plausible without a demonstrated dependency.", "ceiling_from_boundary_check": "Γ" }, { "subclaim_id": "SC3", "field_valid_perturbation_quote": "\n- Endogenous genetic deletion, suppression, or degron depletion of the proposed mediator in vivo\n- Selective pathway inhibition that changes onset/progression while preserving broader viability\n- Vagotomy-type natural experiment, only if confounding is rigorously controlled AND effect is disease-initiation relevant rather than merely associated", "qualifying_evidence_present": "no", "qualifying_evidence_citation": "PMID29422109, PMID26031848, PMID28446653, PMID30381408, PMID41350593, PMID27621223, PMID30218460, PMID27241338, PMID38696328, PMID32595591", "gamma_hard_rules_triggered": [ "No scope-matched origin-attribution fraction is demonstrated." ], "disease_phenotype_relevance": "yes", "perturbation_result_positive": "no", "perturbation_result_note": "No examined study prospectively attributes a meaningful common fraction of sporadic human PD to enteric seeds before CNS disease. Body-first phenotype, sympathetic-first pathology and inferred cross-sectional stage assignments are not synonymous with gut-first vagal initiation. Stronger model results do not supply this registered scope gate.", "ceiling_from_boundary_check": "Γ" } ], "thresholds_tested": [ { "subclaim_id": "SC1", "threshold": "Δ", "requirement_quoted": "Requires at least one genuine causal perturbation in a disease-relevant in vivo system, or equivalent human natural experiment that materially supports the mechanism.", "satisfied": "no", "supporting_evidence": [ "[19] Swedish and PPMI analyses associated earlier appendectomy with lower risk or delayed onset, while normal appendix lysates contained aggregation-associated alpha-synuclein forms." ], "what_would_cross_it": "Prospective paired enteric and CNS seed/activity measures with validated sensitivity show gut abnormality preceding any detectable central involvement, alongside subsequent central conversion." }, { "subclaim_id": "SC2", "threshold": "Δ", "requirement_quoted": "Requires at least one genuine causal perturbation in a disease-relevant in vivo system, or equivalent human natural experiment that materially supports the mechanism.", "satisfied": "no", "supporting_evidence": [ "[15] Human stellate-ganglion Lewy-body extracts injected intracerebrally did not reproduce the long-term nigral degeneration previously seen with nigral extracts.", "[17] Danish registry comparisons associated truncal vagotomy over 20 years before follow-up with lower PD risk than the general population; selective vagotomy was not protective.", "[18] Swedish matched registries found no overall vagotomy association but lower PD hazard for truncal procedures at least five years before diagnosis, without a selective-vagotomy effect.", "[19] Swedish and PPMI analyses associated earlier appendectomy with lower risk or delayed onset, while normal appendix lysates contained aggregation-associated alpha-synuclein forms.", "[33] Duodenal and pyloric preformed-fibril injection produced ordered brain pathology, dopamine-neuron loss and behavioural deficits; truncal vagotomy and Snca deficiency prevented these outcomes.", "[34] Intestinal-wall injection of patient brain lysate or recombinant alpha-synuclein produced time-dependent vagal transport to the rat dorsal motor nucleus; cell imaging supported axonal transport.", "[35] Gastric fibril inoculation induced vagotomy-dependent brainstem aggregates, which declined without further rostral spread through 12 months.", "[36] Enteric PFF or A53T-overexpression experiments produced gut dysfunction but only transient rodent brainstem pathology and no sustained primate CNS pathology at 12 months.", "[37] Even BAC A53T sensitization increased early brainstem aggregates after gut fibrils without sustained caudo-rostral spread to nigra through eight months.", "[38] Gut PFFs caused transient deficits in young mice and persistent deficits with reduced striatal dopamine in aged mice; aged brainstem pathology increased, but midbrain pathology increase was not significant and TH-positive counts were unchanged.", "[39] Gut fibrils produced sympathetic and parasympathetic pathology and possible bidirectional dissemination in BAC rats, while wild-type rats lacked detectable propagation.", "[40] Baboon enteric or striatal patient-extract injection produced both nigrostriatal and enteric lesions, without detectable vagal lesions in the tested setting.", "[41] Gut-injected aggregates spread more extensively through autonomic pathways in aged wild-type rats, with cardiac and gastric dysfunction and more mature aggregates.", "[42] Organoid coculture and epithelial-restricted human-alpha-synuclein mice supported mucosal-to-neural transfer; vagotomy prevented hindbrain templating activity after epithelial induction.", "[44] Seeded enteroendocrine-to-neuronal cell propagation required physical contact and Rab35, with enhanced lysosomal clearance after inhibition.", "[45] Intracerebral transmission of human stomach or brain homogenate produced localized aggregation in sensitized mice, unlike blood or muscle, without overt motor disease.", "[47] Rotenone and fragment-fibril experiments implicated AEP-dependent alpha-synuclein and tau cleavage in enteric and nigral pathology.", "[48] Gut conditional loss of trophic factors produced constipation, dopaminergic loss and motor abnormalities, while human tissue correlations and rotenone models implicated C/EBPbeta.", "[49] C/EBPbeta or AEP deletion reduced age- and rotenone-associated pathology and motor deficits in human-SNCA transgenic mice with apparent gut-to-brain progression.", "[50] Mild chronic DSS gut inflammation accelerated motor dysfunction and nigral marker loss in alpha-synuclein-mutant mice with increased enteric and brain pathology.", "[51] Microbiota depletion, recolonization, metabolites and patient-donor transfer modulated motor deficits and neuroinflammation in alpha-synuclein-overexpressing mice.", "[52] PD-donor microbiota transferred into wild-type mice produced TH-positive cell loss, motor impairment and gut-immune-brain changes.", "[54] Antibiotics reduced progression in a gut-originated model; bacterial and metabolite experiments implicated BCAA-related impaired microglial alpha-synuclein clearance.", "[55] Gut PFF injection in wild-type mice produced temporally mapped central spread and motor and sleep phenotypes, with central dopamine experiments linking REM abnormalities to nigral dysfunction.", "[56] Microbial UrdA and imidazole propionate manipulations increased brain metabolite exposure and PD-like neuronal and behavioural outcomes, with mTORC1 implicated.", "[57] Intestinal inflammation accelerated nigral aggregation and dopaminergic loss in male human-LRRK2-G2019S mice, with sex-chromosome manipulations retaining male susceptibility.", "[58] Human colon inflammation was accompanied by rotenone-model protection after TLR4 knockout despite persistent dysbiosis.", "[59] Colitis induced sustained TH-marker reduction and neuroinflammation in male mice; CD8 depletion prevented the TH change, and colitis increased later MPTP vulnerability.", "[62] A randomized double-blind supplementation report described motor and medication changes over six months alongside immune and barrier outcomes.", "[64] A large Danish matched registry study found a small increased rather than decreased PD hazard at least ten years after appendectomy, persisting after longer follow-up.", "[65] Prospective Nurses' Health and Health Professionals cohorts found no overall reduced PD hazard after self-reported appendectomy, with higher risk for appendicitis-related surgery in women.", "[66] Appendectomy after age 35 did not reduce later PD risk relative to cholecystectomy, and the early increase relative to no surgery disappeared with longer follow-up.", "[67] A Korean national cohort found no statistically resolved appendectomy-PD association, with adjusted hazard confidence limits spanning protection and increased risk.", "[68] A Swedish nested case-control study associated prior appendectomy with lower PD odds, including long lags, with a less precise tonsillectomy association." ], "what_would_cross_it": "Selective interruption of native enteric pathological species transfer, preserving autonomic function and systemic immune/metabolite effects, changes onset/progression with matched restoration or a rigorously controlled human natural experiment." }, { "subclaim_id": "SC3", "threshold": "Δ", "requirement_quoted": "Requires at least one genuine causal perturbation in a disease-relevant in vivo system, or equivalent human natural experiment that materially supports the mechanism.", "satisfied": "no", "supporting_evidence": [ "[15] Human stellate-ganglion Lewy-body extracts injected intracerebrally did not reproduce the long-term nigral degeneration previously seen with nigral extracts.", "[17] Danish registry comparisons associated truncal vagotomy over 20 years before follow-up with lower PD risk than the general population; selective vagotomy was not protective.", "[18] Swedish matched registries found no overall vagotomy association but lower PD hazard for truncal procedures at least five years before diagnosis, without a selective-vagotomy effect.", "[19] Swedish and PPMI analyses associated earlier appendectomy with lower risk or delayed onset, while normal appendix lysates contained aggregation-associated alpha-synuclein forms.", "[62] A randomized double-blind supplementation report described motor and medication changes over six months alongside immune and barrier outcomes.", "[64] A large Danish matched registry study found a small increased rather than decreased PD hazard at least ten years after appendectomy, persisting after longer follow-up.", "[65] Prospective Nurses' Health and Health Professionals cohorts found no overall reduced PD hazard after self-reported appendectomy, with higher risk for appendicitis-related surgery in women.", "[66] Appendectomy after age 35 did not reduce later PD risk relative to cholecystectomy, and the early increase relative to no surgery disappeared with longer follow-up.", "[67] A Korean national cohort found no statistically resolved appendectomy-PD association, with adjusted hazard confidence limits spanning protection and increased risk.", "[68] A Swedish nested case-control study associated prior appendectomy with lower PD odds, including long lags, with a less precise tonsillectomy association." ], "what_would_cross_it": "A representative prospective prodromal cohort estimates the prespecified gut-origin fraction using validated temporal and mediator attribution, with independent replication and brain-/sympathetic-first alternatives tested." } ], "generalization_check": { "generalization_tested": "yes", "context_boundary_mapped": "yes", "internal_negative_controls": [ "Selective versus truncal vagotomy; long-lag and comorbidity analyses.", "PBS/monomer and Snca-null controls in seeded models.", "Young versus aged hosts and negative sustained-spread paradigms.", "Seed-negative normal autopsies and staining-positive healthy colon controls.", "Matched bacterial growth/colonization and metabolite exposure with rapamycin in the ImP model." ], "note": "Tested across human autopsy, prodromal/clinical cohorts, registry exposures and rodent/primate systems. Effects depend on assay, age, transgene, seed preparation, surgical anatomy and clinical subtype. These boundaries were defined from baseline features rather than invented from responders; body-first and enteric-first remain separate scopes." }, "falsification_patterns_met": [ { "pattern": "Peripheral pathology without sustained CNS propagation", "evidence": "PMID29751824, PMID29341898 and PMID31783082 reject unconditional gut-seed sufficiency in tested systems.", "downgrade_applied": false, "note": "Included in scope threshold; no duplicate penalty." }, { "pattern": "Noncanonical or sympathetic-first topology", "evidence": "PMID18053026 and PMID40082617 oppose an obligatory exclusive DMV/vagal sequence.", "downgrade_applied": false, "note": "Already limits SC3, without excluding a subgroup." }, { "pattern": "Inconsistent reservoir-removal effects", "evidence": "Positive Swedish appendix studies coexist with null/increased-risk Danish, prospective Western and Korean analyses.", "downgrade_applied": false, "note": "Instrument uncertainty included in threshold assessment." } ], "pitfalls_flagged": [ { "pitfall": "Premotor treated as pre-CNS", "where": "Biopsy and autonomic imaging before clinical motor diagnosis." }, { "pitfall": "Body-first equated with gut-first", "where": "RBD, cardiac denervation and sympathetic autopsy trajectories." }, { "pitfall": "Forced seed origin naturalized", "where": "PFF and patient-extract gut inoculation." }, { "pitfall": "TH signal equated with cell death", "where": "Challis aged mice and colitis marker changes." }, { "pitfall": "Modelled sequence presented as observed transfer", "where": "SuStaIn and extrapolated imaging duration." } ], "causal_tally_audit": { "tally_claimed_by_document": 34, "tally_after_audit": 34, "items_rejected": [ "Null and negative contrasts are discriminators, not positive threshold crossings. Reports and replications are not independent causal lines.", "A surgery contrast may discriminate reservoir models without satisfying a rigorous origin instrument.", "Route blockade after engineered trigger is not prevention of naturally initiated human disease.", "Corrections and shared specimens limit independent replication; all correction notices were checked at the stated depth." ] }, "steelman": { "case_one_rung_higher": "Δ is attractive because truncal vagotomy changes later PD risk in selected comparisons and epithelial-restricted expression gives a source-specific transfer test. For the registered common human origin gate it would require rigorous confounder/mediator attribution or equivalent native dependency; those positive model results do not measure that gate.", "case_one_rung_lower": "Β would undercredit temporally informative premotor specimens, clinical exposure interruption and direct conditional source-to-recipient transfer. The current mechanism is more than pathology colocalization even though common natural initiation remains unproven.", "which_rejected": "Reject Β as too narrow an account of the mechanistic evidence and reject global Δ because it substitutes conditional transport for common human origin. Γ reflects a plausible but unresolved registered initiating mechanism, with model causality stated separately.", "blocking_cap_threshold_or_missing_experiment": "Missing experiment: Enroll representative prodromal participants before RBD/motor diagnosis, pair serial compartment-specific gut and CSF seeding with autonomic/dopamine imaging, and quantify predefined origin classes. In native disease-relevant models, selectively block enteric pathological-alpha-synuclein transfer while preserving vagal physiology and metabolite/immune signals, with matched restoration and independent replication." }, "final_score": { "hsef_level": "Γ", "hsef_descriptor": "Mechanistically plausible, partial system support", "confidence": "Moderate", "confidence_rationale": "69 primary reports with 6 selected partial-body examinations; density, heterogeneous controls and incomplete access set the confidence, not correctness.", "rests_on_non_peer_reviewed_work": false, "rationale": "Γ for the registered common sporadic enteric-vagal initiation claim. Scope-matched aggregation uses SC3; primary-subclaim and weakest-link sensitivities also return Γ. The assembled evidence exceeds association alone through timing, animal pathway tests and human natural experiments, but does not cross the full-scope initiation dependency threshold. Conditional transport capability is established in particular engineered models, and human body-first phenotypes are separately supported; neither is silently substituted for common natural gut initiation." }, "role_of_mechanism": { "classification": "reinforcing / stabilizing factor", "derivation_step_matched": 5, "derivation": "Step1: gut changes may follow PD, but perturbation experiments show feedback on pathology, so the assembled gut mechanism is not solely downstream. Step2: conditional route and native immune/metabolite effects exclude mere co-occurrence. Step3: common initiating, removable and rate-limiting enteric-vagal origin is not shown. Step4: a universal permissive requirement is contradicted by alternate trajectories. Step5 applies to the defensible broad contribution: gut processes can reinforce degeneration, with stronger route dependencies only in defined experimental settings.", "tournament_used_as_tiebreaker": false, "note": "Derived from causal direction, not tournament rank." }, "extended_scoring_MSD": { "momentum": { "value": "Mechanistic only", "artifact": "Published epithelial-transfer, endogenous c-rel, ImP and longitudinal subtype programmes address specific boundaries; no verified ongoing trial testing common native enteric-vagal initiation is asserted.", "justification": "Published epithelial-transfer, endogenous c-rel, ImP and longitudinal subtype programmes address specific boundaries; no verified ongoing trial testing common native enteric-vagal initiation is asserted." }, "stability": { "value": "Stable", "trigger": "No named pending scope-matched origin-attribution result is verified. The 2026 seed-injection and imaging studies are already included, and an autopsy preprint supplied by Consensus is not treated as an imminent validated crossing.", "justification": "No named pending scope-matched origin-attribution result is verified. The 2026 seed-injection and imaging studies are already included, and an autopsy preprint supplied by Consensus is not treated as an imminent validated crossing." }, "divergence": { "implied_level": null, "implied_level_basis": "No single field-implied level is defensible from conflicting framings.", "assessed_level": "Γ", "gap_in_rungs": null, "value": "Contested", "justification": "No manufactured field consensus or arithmetic gap." }, "calibration_note": "M/S/D never modify HSEF level or confidence." }, "change_record": { "applies": false, "prior_level": "Ranking categorical verdict visible; no prior letter used as a target", "prior_confidence": null, "prior_source": null, "derived_before_consulting_prior": false, "new_level": "Γ", "direction": "newly assigned", "what_moved_it": "Fresh primary evidence appraisal; not blinded.", "divergence_from_other_reviewers": null }, "proposed_decisive_experiments": [ { "name": "Registered boundary experiment", "experiment": "Enroll representative prodromal participants before RBD/motor diagnosis, pair serial compartment-specific gut and CSF seeding with autonomic/dopamine imaging, and quantify predefined origin classes. In native disease-relevant models, selectively block enteric pathological-alpha-synuclein transfer while preserving vagal physiology and metabolite/immune signals, with matched restoration and independent replication.", "readout": "Compartment-specific first positivity, validated detection limits, later nigral neuronal survival and clinical progression, plus a population-attributable gut-origin fraction", "critical_control": "Brain-/sympathetic-first comparators; blinded repeated assays; transit/medication/diet adjustment; normal-alpha-synuclein controls; vagal-function preservation; immune/metabolite controls; matched species-specific restoration", "supporting_result": "Enteric seeds precede central involvement in a substantial prespecified fraction; selective mediator interruption prevents subsequent central spread and degeneration with restoration restoring the sequence", "falsifying_result": "Central seeds precede gut signals, most peripheral-first cases arise elsewhere, or verified enteric-transfer blockade leaves degeneration unchanged while altering only gut function" } ], "knowledge_gaps": [ { "name": "Gap 1", "statement": "Paired temporal attribution: premotor tissue is not pre-CNS tissue; serial peripheral and central assays must start before central prodromal signs (PMID27015771, PMID29866443, PMID37059509).", "relevance": "Limits mechanism identification or scope." }, { "name": "Gap 2", "statement": "Gut versus other peripheral origins: validate enteric, sympathetic and central classes prospectively instead of using RBD as a unique gut surrogate (PMID40082617, PMID38860478, PMID40204988).", "relevance": "Limits mechanism identification or scope." }, { "name": "Gap 3", "statement": "Natural seed generation and selective transfer: separate mutant/human expression, injected seeds and spontaneous pathological conformations with non-disruptive route blockade (PMID38063197, PMID31255487, PMID41207395).", "relevance": "Limits mechanism identification or scope." }, { "name": "Gap 4", "statement": "Vagotomy instrument validity: distinguish surgical era, smoking, indication, survival and physiological effects from removal of a seed conduit; reconcile lags and independent populations (PMID26031848, PMID28446653).", "relevance": "Limits mechanism identification or scope." }, { "name": "Gap 5", "statement": "Degeneration versus dysfunction: corroborate TH/DAT/dopamine changes with neuronal survival and durable clinical trajectories, rather than equating them automatically (PMID32066981, PMID34412704, PMID40913049).", "relevance": "Limits mechanism identification or scope." }, { "name": "Gap 6", "statement": "Specific human mediation: test whether gut interventions change native seed movement, systemic metabolites or immune signals and whether this predicts disease progression beyond symptomatic response (PMID41350593, PMID40913049, PMID39218360).", "relevance": "Limits mechanism identification or scope." } ], "review_metadata": { "review_date": "2026-10-05", "reviewer": "Codex", "evidence_base_note": "69 primary reports; literature cutoff 2026-10-05; source examination UTC date 2026-10-06; bounded critical review, not exhaustive systematic review.", "literature_tools_available": true, "literature_tools_note": "Life Sciences Literature PubMed/Europe PMC; signed-in Consensus browser discovery and attempted indexed full-text extraction. Successful passages and failures are reconciled with original sections where available; see case reconciliation. Zero Consensus API calls.", "skill_version": "5.3", "validator_run": "exact archived v5.3 validator 2.3; see validator.txt", "validator_warnings_addressed": "Phenomenon entry was restated as the preregistered causal claim. No real phenomenon is labelled refuted; warning is explicitly justified.", "consensus_consistency_audit": "2026-10-09; supplementary provenance/source reconciliation; original grading retained; prior grades visible." }, "is_calibration_entry": { "value": false, "entry_role": "not_calibration", "blind_graded": null, "completed_blinded_calibration": false, "expected_band_sealed_at": "", "target_sha256": "", "target_authorship": "not applicable", "target_author_saw_review": null, "future_run_status": "not prepared", "unblinded_reason": "Ranking categorical verdict and index guidance were visible. No completed blinded calibration claimed." }, "upper_ladder_check": { "final_level_below_zeta": true, "equivalents_considered": [ { "kind": "mendelian_randomization", "available": false, "why_not_sufficient": "Human vagotomy and appendectomy natural experiments, a randomized supplement intervention and orthogonal native animal pathways were examined. Surgery associations have unresolved instrument/mediator limits; symptomatic supplementation does not measure trajectory or the vagal seed mediator. No qualifying human genetic instrument on enteric-vagal initiation or convergent upstream human dependency carries the registered claim to Ζ/Η. Upper levels remain reachable without an unethical mechanism RCT." }, { "kind": "natural_experiment", "available": true, "why_not_sufficient": "Human vagotomy and appendectomy natural experiments, a randomized supplement intervention and orthogonal native animal pathways were examined. Surgery associations have unresolved instrument/mediator limits; symptomatic supplementation does not measure trajectory or the vagal seed mediator. No qualifying human genetic instrument on enteric-vagal initiation or convergent upstream human dependency carries the registered claim to Ζ/Η. Upper levels remain reachable without an unethical mechanism RCT." }, { "kind": "dose_response_across_populations", "available": false, "why_not_sufficient": "Human vagotomy and appendectomy natural experiments, a randomized supplement intervention and orthogonal native animal pathways were examined. Surgery associations have unresolved instrument/mediator limits; symptomatic supplementation does not measure trajectory or the vagal seed mediator. No qualifying human genetic instrument on enteric-vagal initiation or convergent upstream human dependency carries the registered claim to Ζ/Η. Upper levels remain reachable without an unethical mechanism RCT." }, { "kind": "withdrawal_rechallenge", "available": false, "why_not_sufficient": "Human vagotomy and appendectomy natural experiments, a randomized supplement intervention and orthogonal native animal pathways were examined. Surgery associations have unresolved instrument/mediator limits; symptomatic supplementation does not measure trajectory or the vagal seed mediator. No qualifying human genetic instrument on enteric-vagal initiation or convergent upstream human dependency carries the registered claim to Ζ/Η. Upper levels remain reachable without an unethical mechanism RCT." }, { "kind": "therapeutic_perturbation_hard_endpoint", "available": false, "why_not_sufficient": "Human vagotomy and appendectomy natural experiments, a randomized supplement intervention and orthogonal native animal pathways were examined. Surgery associations have unresolved instrument/mediator limits; symptomatic supplementation does not measure trajectory or the vagal seed mediator. No qualifying human genetic instrument on enteric-vagal initiation or convergent upstream human dependency carries the registered claim to Ζ/Η. Upper levels remain reachable without an unethical mechanism RCT." } ], "convergence_present": true, "cap_reapplied_to_convergent_set": false }, "provenance_header": { "sources_total": 69, "claims_total": 73, "claims_verified": 73, "claims_unverified": 0, "claims_contradicted": 0, "tier_a_sources": 69, "generated_by": "Codex; HSEF v5.3", "gate_passed": true }, "claims": [ { "id": "C1", "text": "Autopsies identified Lewy bodies in selected enteric neuronal phenotypes, establishing peripheral involvement in diagnosed PD. Three end-stage observations do not establish temporal origin, gut-to-brain movement or common-fraction causation.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 1 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C2", "text": "Cross-sectional incidental and symptomatic brain pathology supported a caudo-rostral staging scheme beginning in selected brainstem/olfactory sites. A topographical stage reconstruction is not longitudinal transport and does not demonstrate enteric initiation before CNS pathology.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 2 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C3", "text": "Systematic multi-organ autopsy staining mapped widespread Lewy pathology with a decreasing upper-to-lower gastrointestinal gradient. Anatomical distribution at death cannot determine direction or initiating organ; peripheral involvement is compatible with descending or parallel disease.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 3 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C4", "text": "Observers across institutions reproducibly assigned brain alpha-synuclein stages using a defined section protocol. Reliability of a classification validates measurement consistency, not temporal order, vagal transmission or etiologic necessity.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 4 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C5", "text": "An unselected alpha-synuclein-positive autopsy series contained deviations from the proposed caudo-rostral pattern and substantial pathology without corresponding clinical syndromes. Deviation undermines universal staging but does not exclude a gut-origin subtype; cross-sectional pathology cannot reconstruct an individual's initiating sequence.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 5 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C6", "text": "Early untreated PD sigmoid biopsies showed a nerve-fibre staining pattern absent from the tested healthy and inflammatory controls. Patients already had motor PD; staining specificity is assay-dependent and does not locate the disease origin before CNS pathology.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 6 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C7", "text": "Archived colon biopsies from three future PD patients contained alpha-synuclein staining before their first motor symptom. Premotor is not pre-CNS; retrospective cases, small numbers and healthy control selection do not determine population prevalence or causal route.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 7 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C8", "text": "Blinded archived gastrointestinal biopsy analysis detected phosphorylated nerve pathology in some patients years before motor onset, including serial samples. Sparse sensitivity and retrospectively ascertained diagnoses limit generalization; no contemporaneous CNS measurements exclude earlier brain disease.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 8 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C9", "text": "Archived gastrointestinal phosphorylated alpha-synuclein staining was detected in 22 of 39 prodromal subjects, sampled on average seven years before diagnosis. Premotor detection does not establish pre-CNS origin; aggregated-alpha-synuclein staining did not differ from controls, and retrospective tissue ascertainment and assay choice constrain prevalence.", "carries_number": true, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 9 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C10", "text": "A multicentre assessment found frequent positive control-biopsy staining and no tested method or pattern with both sensitivity and specificity above 80 percent. Small shared biopsy sets and heterogeneous ratings test assay reliability rather than excluding enteric disease or its causal route.", "carries_number": true, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 10 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C11", "text": "Full-thickness autopsy-colon assessment achieved better discrimination with selected protocols and trained raters, including a perfect result for one method in the tested set. Selected small specimens, sufficient submucosa and reader training limit generalization; shares assay-development components with the earlier biopsy assessment, not independent origin evidence.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 11 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C12", "text": "PET-blot and routine immunohistochemistry detected mucosal alpha-synuclein aggregates in many healthy controls as well as PD, including all 11 PET-blot controls. Assay non-specificity undermines biopsy biomarker interpretation; mucosal staining does not exclude pathogenic conformations in other enteric compartments.", "carries_number": true, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 12 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C13", "text": "Blinded right and left colon assessment found similar alpha-synuclein and phosphorylated staining in 19 PD patients and eight controls. Small cross-sectional samples and antibody patterns cannot determine initiating site, transport direction or the absence of a gut-origin subgroup.", "carries_number": true, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 13 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C14", "text": "Autopsies spanning normal elderly, incidental Lewy pathology and PD found no vagal or gastric phosphorylated-synuclein positivity without brain pathology. Cross-sectional age-related ascertainment, sampled gut regions and detection sensitivity leave transient or unsampled peripheral initiation possible; this is positive counterevidence to a common obligatory sequence, not universal proof of brain-first disease.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 14 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C15", "text": "Human stellate-ganglion Lewy-body extracts injected intracerebrally did not reproduce the long-term nigral degeneration previously seen with nigral extracts. Imposed intracerebral inoculation and sympathetic rather than enteric tissue do not test natural gut initiation; they show that peripheral seed source and conformation can affect pathogenicity.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 15 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C16", "text": "The six-site S4 study compared multiple fluid and tissue alpha-synuclein measures in 59 PD patients and 21 controls and reported limited sensitivity for skin and submandibular staining. Cross-sectional diagnosed disease does not identify origin; the abstract does not report a colon result, and measurements across compartments were not correlated.", "carries_number": true, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 16 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C17", "text": "Danish registry comparisons associated truncal vagotomy over 20 years before follow-up with lower PD risk than the general population; selective vagotomy was not protective. Overall and direct truncal-versus-selective estimates were imprecise and crossed unity; surgical indication, smoking and long-survival selection remain alternative explanations, without direct alpha-synuclein mediator measurement.", "carries_number": true, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 17 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C18", "text": "Swedish matched registries found no overall vagotomy association but lower PD hazard for truncal procedures at least five years before diagnosis, without a selective-vagotomy effect. The truncal overall estimate crossed unity; procedure era, ulcer indication, proxy adjustment and nonrandom exposure constrain route-specific causation and cannot quantify the gut-origin fraction.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 18 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:RESULTS, 2:DISCUSSION. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C19", "text": "Swedish and PPMI analyses associated earlier appendectomy with lower risk or delayed onset, while normal appendix lysates contained aggregation-associated alpha-synuclein forms. Appendectomy changes immunity and microbial niches as well as a possible seed reservoir; effects varied by geography and genetic status and do not directly measure ascending vagal transfer.", "carries_number": false, "load_bearing_for": [ "SC1", "SC2", "SC3" ], "source_ns": [ 19 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C20", "text": "Multimodal imaging separated RBD-associated autonomic dysfunction with relatively preserved dopamine storage from diagnosed PD without RBD dominated by nigrostriatal dysfunction. Cross-sectional trajectory inference, overlapping iRBD comparator participants and functional imaging rather than direct seed tracking do not identify a uniquely enteric initiating site.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 20 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C21", "text": "Twenty-two iRBD patients had extensive autonomic and locus-coeruleus abnormalities while most retained normal-range putaminal dopamine storage. RBD already involves CNS circuitry; normative comparator data and functional dysfunction gradients do not demonstrate a gut-before-CNS sequence; iRBD participants overlap the later subtype study.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 21 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C22", "text": "PPMI cerebrospinal-fluid seed amplification classified diagnosed and many prodromal patients and showed substantial olfactory and genetic subgroup heterogeneity. Diagnostic performance and prodromal positivity do not locate the seed origin; repeated PPMI analyses are not independent patient cohorts and some normal-olfaction cases were seed-negative.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 22 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C23", "text": "Possible premotor-RBD grouping predicted more rapid longitudinal motor-score progression than PD without possible RBD. Original Methods identify a Huashan Hospital cohort of 137 patients, not PPMI. Questionnaire-based RBD, retrospective premotor recall, sex differences and treatment-adjusted observational follow-up do not verify enteric origin.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 23 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results, 2:Discussion, 3:Methods. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C24", "text": "Longitudinal PPMI symptom, imaging and genetic analyses supported stable body-first and brain-first phenotype distinctions and different progression patterns. Shares PPMI data with other reports; proxy-defined subtypes do not identify first tissue or transmission direction; linked erratum is retained and requires attention before detailed quantitative reuse.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 24 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C25", "text": "Two postmortem datasets supported early brain-predominant and peripheral-predominant Lewy patterns; modelled body-first patterns split between vagal and sympathetic predominance. SuStaIn orders cross-sectional scores, not observed transfer; brain-first 51 percent, parasympathetic 27 percent and sympathetic 22 percent are modelled autopsy assignments, not population gut-origin prevalence. Isolated sympathetic cases support peripheral heterogeneity; incomplete Newcastle CNS staging was crossvalidated by inference.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 25 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph3, 1:Results:paragraph17, 1:Results:paragraph18, 1:Results:paragraph19, 1:Results:paragraph20, 1:Results:paragraph21, 1:Results:paragraph22. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C26", "text": "A prospectively followed Italian PD cohort showed greater premotor symptom burden and faster motor-stage progression in probable-premotor-RBD patients. Retrospective symptom recall and RBD-based subtype assignment do not verify source tissue or vagal transfer; 81 of 400 proxy-positive cases do not estimate all natural gut initiation.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 26 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C27", "text": "FDOPA and PPMI DaT imaging associated RBD-linked disease with more symmetric dopaminergic dysfunction. Shares imaging and PPMI cohort components with related reports; asymmetry is compatible with route models but does not trace enteric seeds or exclude intrinsic bilateral vulnerability.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 27 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C28", "text": "A population-based Rochester cohort did not support a stable binary body-first versus brain-first classification across alternative symptom definitions. Definition-sensitive clinical groupings challenge simple subtype proxies rather than proving absence of peripheral initiation; PD and DLB diagnostic composition also varied.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 28 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C29", "text": "Longitudinal cardiac and dopamine imaging across two cohorts yielded modelled sympathetic decline preceding nigrostriatal decline in putative body-first disease. Estimated trajectories and extrapolated prodromal duration are not observed seed transfer or initial enteric pathology; autonomic denervation is a different endpoint from the proposed gut origin.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 29 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C30", "text": "A 24-centre prospective iRBD cohort documented frequent later parkinsonism or dementia and identified constipation and autonomic markers among predictors. RBD already reflects central dysfunction; predictive symptoms do not identify gut origin, and conversion included several synucleinopathies rather than solely sporadic PD.", "carries_number": true, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 30 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C31", "text": "A clinicopathological case documented peripheral sensory neuropathy and archived sural alpha-synuclein staining before overt parkinsonism and DLB. One retrospective non-enteric case without preclinical CNS testing cannot establish common PD initiation or transport direction.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 31 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C32", "text": "In a small at-risk prospective cohort, all four subjects diagnosed with PD over three years had antecedent cardiac sympathetic denervation. Small enriched risk sample and cardiac functional rather than enteric seed measurement cannot locate initiation or exclude earlier CNS disease.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 32 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C33", "text": "Duodenal and pyloric preformed-fibril injection produced ordered brain pathology, dopamine-neuron loss and behavioural deficits; truncal vagotomy and Snca deficiency prevented these outcomes. Exogenous seed injection supplies the proposed initiating event; route necessity within this model does not prove spontaneous human gut initiation or its prevalence.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 33 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C34", "text": "Intestinal-wall injection of patient brain lysate or recombinant alpha-synuclein produced time-dependent vagal transport to the rat dorsal motor nucleus; cell imaging supported axonal transport. Forced inoculation and detectable transport are not native initiation, templated amplification at every relay or demonstrated human nigrostriatal disease.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 34 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C35", "text": "Gastric fibril inoculation induced vagotomy-dependent brainstem aggregates, which declined without further rostral spread through 12 months. Supports a conduit but contradicts route sufficiency under these conditions; imposed seed dose and species may differ from natural PD, and linked correction is retained.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 35 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C36", "text": "Enteric PFF or A53T-overexpression experiments produced gut dysfunction but only transient rodent brainstem pathology and no sustained primate CNS pathology at 12 months. Artificial triggers and tested preparations limit extrapolation; the negative result shows context dependence rather than universal impossibility of gut-to-brain disease.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 36 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C37", "text": "Even BAC A53T sensitization increased early brainstem aggregates after gut fibrils without sustained caudo-rostral spread to nigra through eight months. Overexpression and imposed fibrils do not model endogenous origin; shares preparation and failure mode with the earlier gastric-inoculation programme.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 37 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C38", "text": "Gut PFFs caused transient deficits in young mice and persistent deficits with reduced striatal dopamine in aged mice; aged brainstem pathology increased, but midbrain pathology increase was not significant and TH-positive counts were unchanged. Imposed seeds and age-dependent susceptibility establish conditional capability, not the usual human initiating compartment or a universally sufficient vagal route.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 38 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:RESULTS:paragraph7, 1:RESULTS:paragraph8, 1:RESULTS:paragraph9. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C39", "text": "Gut fibrils produced sympathetic and parasympathetic pathology and possible bidirectional dissemination in BAC rats, while wild-type rats lacked detectable propagation. Transgenic susceptibility and artificial seeds constrain native causation; sympathetic and anterograde routes undermine an exclusive unidirectional vagal account.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 39 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C40", "text": "Baboon enteric or striatal patient-extract injection produced both nigrostriatal and enteric lesions, without detectable vagal lesions in the tested setting. Imposed extracts and small primate experiments do not establish a spontaneous route; circulating transfer is a proposed explanation rather than directly traced mediation, and linked correction is retained. A 2025 publisher correction reports duplicated/misassigned representative panels; corrected images and raw data were not audited, so this is qualified rather than singular decisive evidence. A 2025 publisher correction reports duplicated/misassigned representative panels; corrected images and raw data were not audited, so this is qualified rather than singular decisive evidence.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 40 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C41", "text": "Gut-injected aggregates spread more extensively through autonomic pathways in aged wild-type rats, with cardiac and gastric dysfunction and more mature aggregates. Age improves physiological relevance but initiation remains imposed; bidirectionality and sympathetic routes do not establish a solely vagal natural human origin.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 41 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C42", "text": "Organoid coculture and epithelial-restricted human-alpha-synuclein mice supported mucosal-to-neural transfer; vagotomy prevented hindbrain templating activity after epithelial induction. Original Methods/Results identify mixed wild-type/A30P/A53T transgenes restricted to gut mucosa and pre-induction vagotomy with about 15 percent weight loss. Modest expression and in-situ seed formation are stronger than injected fibrils, but neuronal uptake need not involve recipient templating; no nigral-loss endpoint or common human origin is established.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 42 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph1, 1:Results:paragraph3, 1:Results:paragraph4, 2:Discussion, 3:Methods. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C43", "text": "Human and mouse enteroendocrine cells expressed alpha-synuclein and connected to alpha-synuclein-containing nerves, identifying a possible mucosal source compartment. Expression and anatomical contact are not pathological misfolding, transfer or causal PD; the paper's premise that enteric pathology precedes brain pathology is not demonstrated by this experiment.", "carries_number": false, "load_bearing_for": [ "SC1", "SC2" ], "source_ns": [ 43 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C44", "text": "Seeded enteroendocrine-to-neuronal cell propagation required physical contact and Rab35, with enhanced lysosomal clearance after inhibition. Cell lines and added fibrils test a transfer mechanism rather than endogenous whole-animal or human gut initiation and degeneration.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 44 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C45", "text": "Intracerebral transmission of human stomach or brain homogenate produced localized aggregation in sensitized mice, unlike blood or muscle, without overt motor disease. Imposed intracerebral delivery bypasses vagal transport; subtle aggregation after long incubation is not PD neurodegeneration or a native enteric origin, and linked erratum is retained. The correction changes stomach-homogenate pathology denominators including 7/7 to 7/14; no uncorrected rate is used. The correction changes stomach-homogenate pathology denominators including 7/7 to 7/14; no uncorrected rate is used.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 45 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C46", "text": "Amplification assays detected seeding from fixed gastric and brain tissues and regionally different assemblies, without a consistent region-specific seeding gradient. Formalin and in-vitro amplification can alter detectable seed properties; postmortem tissue and strain differences cannot determine temporal or transport direction.", "carries_number": false, "load_bearing_for": [ "SC1", "SC2" ], "source_ns": [ 46 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C47", "text": "Rotenone and fragment-fibril experiments implicated AEP-dependent alpha-synuclein and tau cleavage in enteric and nigral pathology. Systemic neurotoxin effects and forced fragment seeds do not isolate a natural enteric starting site; dependence on AEP does not alone establish vagal mediation in sporadic humans.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 47 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C48", "text": "Gut conditional loss of trophic factors produced constipation, dopaminergic loss and motor abnormalities, while human tissue correlations and rotenone models implicated C/EBPbeta. A targeted endogenous trophic perturbation supports gut influence on degeneration; it does not by itself identify alpha-synuclein transfer as the necessary mediator or quantify spontaneous human gut initiation.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 48 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C49", "text": "C/EBPbeta or AEP deletion reduced age- and rotenone-associated pathology and motor deficits in human-SNCA transgenic mice with apparent gut-to-brain progression. Human-protein transgenesis, global pathway effects and toxin exposure complicate origin-specific mediation; related reports share pathway and laboratory components.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 49 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C50", "text": "Mild chronic DSS gut inflammation accelerated motor dysfunction and nigral marker loss in alpha-synuclein-mutant mice with increased enteric and brain pathology. Genetic sensitization and inflammatory perturbation do not isolate vagal alpha-synuclein transfer from immune or systemic influences; acceleration is not proof of initial human cause.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 50 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C51", "text": "Microbiota depletion, recolonization, metabolites and patient-donor transfer modulated motor deficits and neuroinflammation in alpha-synuclein-overexpressing mice. Overexpression and microbiome manipulation support a gut modifier; they do not establish enteric seeds ascending the vagus, and germ-free developmental and donor effects limit transfer.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 51 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C52", "text": "PD-donor microbiota transferred into wild-type mice produced TH-positive cell loss, motor impairment and gut-immune-brain changes. Donor medications, recipient conditioning and systemic immune or barrier routes require separation from vagal transfer; TH-positive counts need corroboration of neuron survival before equating them to complete neuronal death.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 52 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C53", "text": "Endogenous global c-rel knockout mice showed early proximal-colon alpha-synuclein accumulation with later oxidative stress, inflammation and enteric TH-positive loss. Global genotype can affect gut and brain in parallel; the reported colon time course does not prove transfer necessity or exclude an independently initiating CNS defect.", "carries_number": false, "load_bearing_for": [ "SC1", "SC2" ], "source_ns": [ 53 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C54", "text": "Antibiotics reduced progression in a gut-originated model; bacterial and metabolite experiments implicated BCAA-related impaired microglial alpha-synuclein clearance. The abstract does not specify how the initiating mouse model was generated; route dependence and primary origin cannot be assumed, and antibiotic effects extend beyond the identified metabolite.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 54 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C55", "text": "Gut PFF injection in wild-type mice produced temporally mapped central spread and motor and sleep phenotypes, with central dopamine experiments linking REM abnormalities to nigral dysfunction. Exogenous seeds impose the initiating lesion; RBD-like animal behaviours do not establish a human gut-first subtype, and the final report replaces its preprint.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 55 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C56", "text": "Microbial UrdA and imidazole propionate manipulations increased brain metabolite exposure and PD-like neuronal and behavioural outcomes, with mTORC1 implicated. Original Results include Nissl/TH stereology, matched bacterial colonization and rapamycin protection without lowering ImP exposure. Germ-free or antibiotic conditioning and administered metabolites constrain transfer; the human plasma comparison follows a mean 9.5 years of PD and cannot establish initiation.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 56 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph3, 1:Results:paragraph5, 1:Results:paragraph9, 1:Results:paragraph13, 1:Results:paragraph14, 1:Results:paragraph16, 1:Results:paragraph17. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C57", "text": "Intestinal inflammation accelerated nigral aggregation and dopaminergic loss in male human-LRRK2-G2019S mice, with sex-chromosome manipulations retaining male susceptibility. A familial-risk genotype and induced colitis support conditional gut influence; myeloid transport, inflammatory signalling and direct vagal transfer remain distinct possibilities.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 57 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C58", "text": "Human colon inflammation was accompanied by rotenone-model protection after TLR4 knockout despite persistent dysbiosis. Global receptor deletion and neurotoxin exposure do not isolate gut-to-vagus seeds; human cross-sectional inflammation could follow disease, transit or medication changes.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 58 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C59", "text": "Colitis induced sustained TH-marker reduction and neuroinflammation in male mice; CD8 depletion prevented the TH change, and colitis increased later MPTP vulnerability. Dopamine itself was not reduced after colitis; immune effects and neurotoxin susceptibility are not proven neuron death or alpha-synuclein vagal transfer, providing an alternative gut-brain mediator.", "carries_number": true, "load_bearing_for": [ "SC2" ], "source_ns": [ 59 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C60", "text": "Cross-sectional early-PD, RBD and relatives showed dysbiosis including depleted butyrate-producing bacteria after adjustment for several transit and medication variables. RBD and family-enriched associations do not establish direction, first seed tissue or transmission; residual diet and shared-environment confounding remain.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 60 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C61", "text": "A small subtype-classified metagenomic study found different microbial and curli-related gene profiles in body-first proxy groups. Cross-sectional 15-versus-nine subgroup comparisons, transit and treatment can explain microbiome patterns; inferred microbial functions are not measured human seed transfer.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 61 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C62", "text": "A randomized double-blind supplementation report described motor and medication changes over six months alongside immune and barrier outcomes. The abstract does not establish an inactive comparator or enteric-seed/vagal mediator; retrospective registration, concurrent PD therapy and symptom change cannot prove disease modification or primary origin.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 62 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C63", "text": "Quantitative gastrointestinal autopsy comparison found preserved myenteric neuron density despite enteric Lewy pathology, whose distribution followed parasympathetic input. End-stage density and staining do not exclude prior functional injury or origin; the result challenges attributing gut dysfunction directly to enteric neuron loss.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 63 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C64", "text": "A large Danish matched registry study found a small increased rather than decreased PD hazard at least ten years after appendectomy, persisting after longer follow-up. Nonrandom surgery and inflammation-related indications remain confounders; contradicts a simple universal appendix-reservoir protection prediction without excluding a subset effect.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 64 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C65", "text": "Prospective Nurses' Health and Health Professionals cohorts found no overall reduced PD hazard after self-reported appendectomy, with higher risk for appendicitis-related surgery in women. Exposure recall and operative indication affect inference; results oppose simple reservoir-removal protection but do not test vagal transfer directly.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 65 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C66", "text": "Appendectomy after age 35 did not reduce later PD risk relative to cholecystectomy, and the early increase relative to no surgery disappeared with longer follow-up. Midlife surgery may miss an earlier initiation window; comparator procedures and indication confounding leave subtype-specific effects unresolved.", "carries_number": true, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 66 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C67", "text": "A Korean national cohort found no statistically resolved appendectomy-PD association, with adjusted hazard confidence limits spanning protection and increased risk. Imprecision and nonrandom surgery preclude interpreting a null test as equivalence or excluding an earlier subtype-specific reservoir.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 67 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C68", "text": "A Swedish nested case-control study associated prior appendectomy with lower PD odds, including long lags, with a less precise tonsillectomy association. Overlaps national register source populations with earlier Swedish studies; surgical indications, smoking proxies and hospital-use ascertainment do not isolate alpha-synuclein reservoir removal.", "carries_number": false, "load_bearing_for": [ "SC2", "SC3" ], "source_ns": [ 68 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "C69", "text": "Seventy-one PD brains included widespread noncanonical staging and cases without DMV involvement despite nigral or cortical pathology. Autopsy sampling and lesion clearance limit temporal inference; shows the DMV is not universally obligatory, without quantifying how often gut-vagal origin occurs.", "carries_number": false, "load_bearing_for": [ "SC1", "SC3" ], "source_ns": [ 69 ], "verification": "verified", "verified_against": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "verified_on": "2026-10-06", "note": "" }, { "id": "CSC1", "text": "Premotor enteric pathology and autonomic dysfunction are reproducible in selected groups, but motor diagnosis is not the onset of CNS pathology. Serial paired gut and central seed measurements establishing enteric-before-CNS order are absent from the examined causal case; sampled autopsies provide contrary patterns.", "carries_number": false, "load_bearing_for": [ "SC1" ], "source_ns": [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 43, 46, 53, 60, 61, 63, 69 ], "verification": "verified", "verified_against": "Synthesis of examined primary result/limit cards; framework level is adjudication.", "verified_on": "2026-10-06", "note": "" }, { "id": "CSC2", "text": "Vagal continuity is causally relevant in imposed-seed and engineered gut-mucosal systems. The latter generates seeds in situ and is credited beyond injected fibrils, yet uses human transgenes and does not establish nigral loss. Registry vagotomy is suggestive but not a rigorously isolated natural-origin instrument; the native human disease route remains plausible without a demonstrated dependency.", "carries_number": false, "load_bearing_for": [ "SC2" ], "source_ns": [ 15, 17, 18, 19, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 62, 64, 65, 66, 67, 68 ], "verification": "verified", "verified_against": "Synthesis of examined primary result/limit cards; framework level is adjudication.", "verified_on": "2026-10-06", "note": "" }, { "id": "CSC3", "text": "No examined study prospectively attributes a meaningful common fraction of sporadic human PD to enteric seeds before CNS disease. Body-first phenotype, sympathetic-first pathology and inferred cross-sectional stage assignments are not synonymous with gut-first vagal initiation. Stronger model results do not supply this registered scope gate.", "carries_number": false, "load_bearing_for": [ "SC3" ], "source_ns": [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 ], "verification": "verified", "verified_against": "Synthesis of examined primary result/limit cards; framework level is adjudication.", "verified_on": "2026-10-06", "note": "" }, { "id": "CH", "text": "Gut-to-brain transfer is experimentally possible; a common enteric-vagal origin of sporadic Parkinson disease remains unestablished.", "carries_number": false, "load_bearing_for": [ "SC3" ], "source_ns": [ 33, 42, 14, 25, 18, 28 ], "verification": "verified", "verified_against": "Bounded synthesis of examined sources; score is adjudication.", "verified_on": "2026-10-06", "note": "" } ], "citation_ledger": [ { "n": 1, "citation": "Wakabayashi K, Takahashi H, Ohama E et al. Parkinson's disease: an immunohistochemical study of Lewy body-containing neurons in the enteric nervous system. Acta neuropathologica. 1990.", "tier": "A", "kind": "primary", "pmid": "1972853", "doi": "10.1007/BF00294234", "url": "https://pubmed.ncbi.nlm.nih.gov/1972853/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID1972853", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C1", "CSC1", "CSC3" ] }, { "n": 2, "citation": "Braak H, Del Tredici K, Rüb U et al. Staging of brain pathology related to sporadic Parkinson's disease. 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Acta neuropathologica communications. 2016.", "tier": "A", "kind": "primary", "pmid": "27044604", "doi": "10.1186/s40478-016-0305-8", "url": "https://pubmed.ncbi.nlm.nih.gov/27044604/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27044604", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C10", "CSC1", "CSC3" ] }, { "n": 11, "citation": "Beach TG, Corbillé AG, Letournel F et al. Multicenter Assessment of Immunohistochemical Methods for Pathological Alpha-Synuclein in Sigmoid Colon of Autopsied Parkinson's Disease and Control Subjects. Journal of Parkinson's disease. 2016.", "tier": "A", "kind": "primary", "pmid": "27589538", "doi": "10.3233/JPD-160888", "url": "https://pubmed.ncbi.nlm.nih.gov/27589538/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27589538", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C11", "CSC1", "CSC3" ] }, { "n": 12, "citation": "Visanji NP, Marras C, Kern DS et al. Colonic mucosal a-synuclein lacks specificity as a biomarker for Parkinson disease. Neurology. 2015.", "tier": "A", "kind": "primary", "pmid": "25589666", "doi": "10.1212/WNL.0000000000001240", "url": "https://pubmed.ncbi.nlm.nih.gov/25589666/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID25589666", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C12", "CSC1", "CSC3" ] }, { "n": 13, "citation": "Antunes L, Frasquilho S, Ostaszewski M et al. Similar α-Synuclein staining in the colon mucosa in patients with Parkinson's disease and controls. 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Journal of Parkinson's disease. 2021.", "tier": "A", "kind": "primary", "pmid": "34151862", "doi": "10.3233/JPD-212733", "url": "https://pubmed.ncbi.nlm.nih.gov/34151862/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID34151862", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C14", "CSC1", "CSC3", "CH" ] }, { "n": 15, "citation": "Recasens A, Carballo-Carbajal I, Parent A et al. Lack of pathogenic potential of peripheral α-synuclein aggregates from Parkinson's disease patients. Acta neuropathologica communications. 2018.", "tier": "A", "kind": "primary", "pmid": "29422109", "doi": "10.1186/s40478-018-0509-1", "url": "https://pubmed.ncbi.nlm.nih.gov/29422109/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID29422109", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C15", "CSC2", "CSC3" ] }, { "n": 16, "citation": "Chahine LM, Beach TG, Brumm MC et al. In vivo distribution of α-synuclein in multiple tissues and biofluids in Parkinson disease. Neurology. 2020.", "tier": "A", "kind": "primary", "pmid": "32747521", "doi": "10.1212/WNL.0000000000010404", "url": "https://pubmed.ncbi.nlm.nih.gov/32747521/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID32747521", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C16", "CSC1", "CSC3" ] }, { "n": 17, "citation": "Svensson E, Horváth-Puhó E, Thomsen RW et al. Vagotomy and subsequent risk of Parkinson's disease. Annals of neurology. 2015.", "tier": "A", "kind": "primary", "pmid": "26031848", "doi": "10.1002/ana.24448", "url": "https://pubmed.ncbi.nlm.nih.gov/26031848/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID26031848", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C17", "CSC2", "CSC3" ] }, { "n": 18, "citation": "Liu B, Fang F, Pedersen NL et al. Vagotomy and Parkinson disease: A Swedish register-based matched-cohort study. Neurology. 2017.", "tier": "A", "kind": "primary", "pmid": "28446653", "doi": "10.1212/WNL.0000000000003961", "url": "https://pubmed.ncbi.nlm.nih.gov/28446653/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Swedish-register-overlapping-source", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:RESULTS, 2:DISCUSSION. No complete-paper or supplement audit claimed.", "carries_claims": [ "C18", "CSC2", "CSC3", "CH" ] }, { "n": 19, "citation": "Killinger BA, Madaj Z, Sikora JW et al. The vermiform appendix impacts the risk of developing Parkinson's disease. Science translational medicine. 2018.", "tier": "A", "kind": "primary", "pmid": "30381408", "doi": "10.1126/scitranslmed.aar5280", "url": "https://pubmed.ncbi.nlm.nih.gov/30381408/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Swedish-register-plus-PPMI", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C19", "CSC1", "CSC2", "CSC3" ] }, { "n": 20, "citation": "Horsager J, Andersen KB, Knudsen K et al. Brain-first versus body-first Parkinson's disease: a multimodal imaging case-control study. Brain : a journal of neurology. 2020.", "tier": "A", "kind": "primary", "pmid": "32830221", "doi": "10.1093/brain/awaa238", "url": "https://pubmed.ncbi.nlm.nih.gov/32830221/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Danish-iRBD-imaging-overlap", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C20", "CSC1", "CSC3" ] }, { "n": 21, "citation": "Knudsen K, Fedorova TD, Hansen AK et al. In-vivo staging of pathology in REM sleep behaviour disorder: a multimodality imaging case-control study. The Lancet. Neurology. 2018.", "tier": "A", "kind": "primary", "pmid": "29866443", "doi": "10.1016/S1474-4422(18)30162-5", "url": "https://pubmed.ncbi.nlm.nih.gov/29866443/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Danish-iRBD-imaging-overlap", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C21", "CSC1", "CSC3" ] }, { "n": 22, "citation": "Siderowf A, Concha-Marambio L, Lafontant DE et al. Assessment of heterogeneity among participants in the Parkinson's Progression Markers Initiative cohort using α-synuclein seed amplification: a cross-sectional study. The Lancet. Neurology. 2023.", "tier": "A", "kind": "primary", "pmid": "37059509", "doi": "10.1016/S1474-4422(23)00109-6", "url": "https://pubmed.ncbi.nlm.nih.gov/37059509/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PPMI-overlapping-source-cohort", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C22", "CSC1", "CSC3" ] }, { "n": 23, "citation": "Xu Z, Hu T, Xu C et al. Disease progression in proposed brain-first and body-first Parkinson's disease subtypes. NPJ Parkinson's disease. 2024.", "tier": "A", "kind": "primary", "pmid": "38834646", "doi": "10.1038/s41531-024-00730-1", "url": "https://pubmed.ncbi.nlm.nih.gov/38834646/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38834646", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results, 2:Discussion, 3:Methods. No complete-paper or supplement audit claimed.", "carries_claims": [ "C23", "CSC1", "CSC3" ] }, { "n": 24, "citation": "Passaretti M, Veréb D, Mijalkov M et al. Clinical progression and genetic pathways in body-first and brain-first Parkinson's disease. Molecular neurodegeneration. 2025.", "tier": "A", "kind": "primary", "pmid": "40542411", "doi": "10.1186/s13024-025-00866-5", "url": "https://pubmed.ncbi.nlm.nih.gov/40542411/", "status_flags": [ "ErratumIn: PMID40830880" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PPMI-overlapping-source-cohort", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C24", "CSC1", "CSC3" ] }, { "n": 25, "citation": "Andersen KB, Krishnamurthy A, Just MK et al. Sympathetic and parasympathetic subtypes of body-first Lewy body disease observed in postmortem tissue from prediagnostic individuals. Nature neuroscience. 2025.", "tier": "A", "kind": "primary", "pmid": "40082617", "doi": "10.1038/s41593-025-01910-9", "url": "https://pubmed.ncbi.nlm.nih.gov/40082617/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID40082617", "access_depth": "full_text_partial", "access_note": "Complete primary abstract and linked-status metadata examined. Selected body sections: 1:Results:paragraph3, 1:Results:paragraph17, 1:Results:paragraph18, 1:Results:paragraph19, 1:Results:paragraph20, 1:Results:paragraph21, 1:Results:paragraph22. No complete-paper or supplement audit claimed.", "carries_claims": [ "C25", "CSC1", "CSC3", "CH" ] }, { "n": 26, "citation": "Velucci V, Gigante AF, Iliceto G et al. The natural history of body-first versus brain-first Parkinson's disease subtypes. Journal of neurology. 2025.", "tier": "A", "kind": "primary", "pmid": "40204988", "doi": "10.1007/s00415-025-13050-y", "url": "https://pubmed.ncbi.nlm.nih.gov/40204988/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID40204988", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C26", "CSC1", "CSC3" ] }, { "n": 27, "citation": "Knudsen K, Fedorova TD, Horsager J et al. Asymmetric Dopaminergic Dysfunction in Brain-First versus Body-First Parkinson's Disease Subtypes. Journal of Parkinson's disease. 2021.", "tier": "A", "kind": "primary", "pmid": "34334424", "doi": "10.3233/JPD-212761", "url": "https://pubmed.ncbi.nlm.nih.gov/34334424/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Danish-imaging-plus-PPMI", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C27", "CSC1", "CSC3" ] }, { "n": 28, "citation": "Camerucci E, Mullan AF, Turcano P et al. A Population-Based Approach to the Argument on Brain-First and Body-First Pathogenesis of Lewy Body Disease. Annals of neurology. 2024.", "tier": "A", "kind": "primary", "pmid": "38860478", "doi": "10.1002/ana.27006", "url": "https://pubmed.ncbi.nlm.nih.gov/38860478/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38860478", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C28", "CSC1", "CSC3", "CH" ] }, { "n": 29, "citation": "Skjærbæk C, Munk OL, Andersen KB et al. Cardiac sympathetic degeneration informs the duration of the prodromal stage of body-first Lewy body disease. NPJ Parkinson's disease. 2026.", "tier": "A", "kind": "primary", "pmid": "42386728", "doi": "10.1038/s41531-026-01455-z", "url": "https://pubmed.ncbi.nlm.nih.gov/42386728/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID42386728", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C29", "CSC1", "CSC3" ] }, { "n": 30, "citation": "Postuma RB, Iranzo A, Hu M et al. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study. 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Movement disorders : official journal of the Movement Disorder Society. 2016.", "tier": "A", "kind": "primary", "pmid": "27621223", "doi": "10.1002/mds.26761", "url": "https://pubmed.ncbi.nlm.nih.gov/27621223/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27621223", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C64", "CSC2", "CSC3" ] }, { "n": 65, "citation": "Palacios N, Hughes KC, Cereda E et al. Appendectomy and risk of Parkinson's disease in two large prospective cohorts of men and women. Movement disorders : official journal of the Movement Disorder Society. 2018.", "tier": "A", "kind": "primary", "pmid": "30218460", "doi": "10.1002/mds.109", "url": "https://pubmed.ncbi.nlm.nih.gov/30218460/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID30218460", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C65", "CSC2", "CSC3" ] }, { "n": 66, "citation": "Marras C, Lang AE, Austin PC et al. Appendectomy in mid and later life and risk of Parkinson's disease: A population-based study. Movement disorders : official journal of the Movement Disorder Society. 2016.", "tier": "A", "kind": "primary", "pmid": "27241338", "doi": "10.1002/mds.26670", "url": "https://pubmed.ncbi.nlm.nih.gov/27241338/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID27241338", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C66", "CSC2", "CSC3" ] }, { "n": 67, "citation": "Park KW, Woo HT, Hwang YS et al. Appendectomy and the Risk of Parkinson's Disease: A Korean Nationwide Study. Movement disorders clinical practice. 2024.", "tier": "A", "kind": "primary", "pmid": "38696328", "doi": "10.1002/mdc3.14031", "url": "https://pubmed.ncbi.nlm.nih.gov/38696328/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID38696328", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C67", "CSC2", "CSC3" ] }, { "n": 68, "citation": "Liu B, Fang F, Ye W et al. Appendectomy, Tonsillectomy and Parkinson's Disease Risk: A Swedish Register-Based Study. Frontiers in neurology. 2020.", "tier": "A", "kind": "primary", "pmid": "32595591", "doi": "10.3389/fneur.2020.00510", "url": "https://pubmed.ncbi.nlm.nih.gov/32595591/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "Swedish-register-overlapping-source", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C68", "CSC2", "CSC3" ] }, { "n": 69, "citation": "Kalaitzakis ME, Graeber MB, Gentleman SM et al. The dorsal motor nucleus of the vagus is not an obligatory trigger site of Parkinson's disease: a critical analysis of alpha-synuclein staging. Neuropathology and applied neurobiology. 2008.", "tier": "A", "kind": "primary", "pmid": "18053026", "doi": "10.1111/j.1365-2990.2007.00923.x", "url": "https://pubmed.ncbi.nlm.nih.gov/18053026/", "status_flags": [ "none_found" ], "opened": true, "opened_on": "2026-10-06", "status_checked_on": "2026-10-06", "study_id": "PMID18053026", "access_depth": "abstract_metadata", "access_note": "Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed.", "carries_claims": [ "C69", "CSC1", "CSC3" ] } ], "independence_basis": { "required": false, "lines": [ { "label": "Human exposure interruption", "sources": [ 17, 18 ], "excludes_error": "Tests future clinical PD after anatomical interruption; distinct from staining, but both share ulcer/smoking confounding." }, { "label": "Species and seed perturbations", "sources": [ 33, 36, 40 ], "excludes_error": "Tests route capability and limits across species rather than deriving order from autopsy." }, { "label": "Native alternative gut mediators", "sources": [ 59, 56 ], "excludes_error": "Tests immune/metabolite influence without requiring enteric seeds to traverse the vagus." } ], "shared_failure_mode_checked": true, "note": "69 reports are not 69 independent causal lines. PPMI, Danish imaging comparators, Swedish population registers, shared tissue archives and related seed/pathway programmes are identified. 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