Gut microbiota in patients with Parkinson’s disease in southern China Original paper

What was studied?

Gut microbiota in Parkinson’s disease was the focus of this original research article, which examined whether patients with Parkinson’s disease (PD) in southern China exhibit distinct microbial signatures compared with healthy controls. The study also investigated whether different PD motor phenotypes show unique microbiome patterns. Using 16S rRNA next-generation sequencing of fecal samples, the researchers quantified microbial diversity, overall community structure, and taxonomic shifts across phylum, family, and genus levels. They also applied diversity metrics, UniFrac distances, and LEfSe analyses to identify taxa associated with disease presence, disease duration, age of onset, and motor subtype. These methods enabled fine-scale detection of microbial signatures that may serve as biomarkers or mechanistic contributors to PD pathology.

Who was studied?

A total of 120 adults from southern China participated, including 75 clinically diagnosed PD patients and 45 healthy controls, largely spouses of cases, to minimize dietary and environmental variability. PD diagnoses followed the 2015 Movement Disorder Society criteria, and all patients were receiving standard antiparkinsonian medications. Exclusion criteria removed individuals with secondary Parkinsonism, recent probiotics or antibiotics exposure, and gastrointestinal diseases. Controls had no history of neurodegenerative disorders or GI pathology. Clinical data included age, BMI, diet, UPDRS motor scores, Hoehn & Yahr stage, and Wexner constipation scores, enabling assessment of clinical correlations with microbial patterns.

Most important findings

Across the cohort, overall alpha diversity did not differ significantly, but PD patients exhibited marked shifts in microbial composition. Firmicutes, Tenericutes, and Euryarchaeota were significantly reduced. At the family level, 17 families decreased while four increased in PD. Lachnospiraceae—a key butyrate-producing family—was reduced by 42.9%. Conversely, Bifidobacteriaceae, Desulfovibrionaceae, and Verrucomicrobiaceae were enriched, with Bifidobacteriaceae showing a strong PD-associated increase despite limited COMT-inhibitor exposure. These shifts suggest a pattern of reduced SCFA-producing bacteria and increased taxa associated with mucosal inflammation or metabolic stress.

Motor phenotype analyses showed no major differences in global microbial composition; however, specific taxa varied. Roseburia (a Lachnospiraceae butyrate producer) was enriched in non-tremor-dominant PD, while Leptotrichia was higher in tremor-dominant disease. Early-onset PD exhibited enrichment of Pasteurellaceae, Alcaligenaceae, Lactococcus, Faecalibacterium, and Haemophilus, whereas Comamonas and Anaerotruncus were more abundant in late-onset PD. Disease duration over five years was linked to elevated Rikenellaceae and Deferribacteraceae, suggesting microbiome evolution as PD progresses.

Key implications

This study demonstrates that PD in southern China is characterized by consistent microbial alterations—particularly reduced SCFA-producing Firmicutes and increased Bifidobacteriaceae and other pro-inflammatory taxa. These changes align with hypotheses linking gut dysbiosis, barrier dysfunction, and neuroinflammation via the gut–brain axis. The identification of phenotype-specific taxa indicates that microbial signatures may help distinguish PD subtypes or track progression, supporting their potential as biomarkers. The findings further reinforce SCFA-related pathways and mucosal immune interactions as promising therapeutic and diagnostic targets.

Citation

Lin A, Zheng W, He Y, et al. Gut microbiota in patients with Parkinson’s disease in southern China. Parkinsonism Relat Disord. 2018;53:82-88. doi:10.1016/j.parkreldis.2018.05.007