Gut microbiome differs in Parkinson's

The research record

This is the project's file for this landmark, as written and checked. Sources are listed at the end; anything not yet confirmed is marked "Not yet verified".

Who

Filip Scheperjans, Aho, Pereira, Koskinen and colleagues, Helsinki (13 authors, published online Dec 2014, Movement Disorders 2015;30:350). Zachary Wallen, Haydeh Payami and colleagues, University of Alabama at Birmingham (8 authors, Nature Communications 2022;13:6958). Funders not recorded here.

What happened

Braak's staging put early disease in the gut and lower brainstem (landmark 6), so researchers looked at gut bacteria.

• Scheperjans 2015. 72 patients and 72 controls, 16S rRNA sequencing of stool. Bacteria of the Prevotellaceae family were 77.6% less abundant in patients. Enterobacteriaceae were linked to worse balance and walking problems.
• Wallen 2022. Shotgun sequencing of stool from 490 patients and 234 controls. Over 30% of the species, genes and pathways tested had altered abundance. The authors described an overabundance of pathogens and immune-provoking components and a loss of anti-inflammatory, protective factors.

Why it moved us toward a cure

It supports the idea that the gut is involved in the disease. Mouse work followed (landmark 56), which raises the chance of treating the microbiome. It does not show the bacteria cause the disease.

Outcome

Open. Differences may be partly a result of the illness, diet, constipation or medicines. The Prevotellaceae cut-off in 2015 was poorly specific (sensitivity 86.1%, specificity 38.9%). A 2024 randomised trial of faecal transplant found it safe but with no clinically meaningful improvement (JAMA Neurol 2024, NCT04854291).

Sources

• Scheperjans et al., Mov Disord 2015;30:350–358, DOI 10.1002/mds.26069, PMID 25476529 (abstract read via Europe PMC)
• Wallen et al., Nat Commun 2022;13:6958, DOI 10.1038/s41467-022-34667-x, PMID 36376318 (PubMed; abstract read via Europe PMC)
• FMT randomised trial, JAMA Neurol 2024, DOI 10.1001/jamaneurol.2024.2305 (abstract only)
• No correction or retraction found for the two papers; both have only linked comments (Europe PMC, 20 Oct 2026).
• Not yet verified: Wallen's control for medicines and constipation; replication of Prevotellaceae loss in other countries; the size and design details of the FMT trial.
• Parent choice: 56 is dated 2016, after Scheperjans (2015), so landmark 6 is used as parent; 56 builds on this one.