ALTERATIONS in the gut microbiota are evident not only in patients with Parkinson’s disease but also in individuals with isolated REM sleep behavior disorder, suggesting that microbial changes may precede clinical onset of Parkinson’s.
In this study, stool samples were collected from 32 individuals with isolated REM sleep behavior disorder, 23 patients with clinical Parkinson’s disease, and 34 healthy controls. Using 16S rDNA sequencing, the investigators assessed the composition and diversity of the intestinal microbiota to determine whether differences were already apparent during the prodromal phase of Parkinson’s.
The analysis revealed significant changes in beta diversity between both Parkinson’s and isolated REM sleep disorder groups compared with healthy controls. Importantly, individuals with isolated REM sleep behavior disorder demonstrated an increase in proinflammatory bacterial species, mirroring patterns also observed in Parkinson’s disease. Patients with Parkinson’s further showed a marked reduction in short chain fatty acid–producing bacteria, which are widely recognized for their anti-inflammatory properties and role in maintaining intestinal homeostasis.
These findings reinforce the hypothesis that gut microbial dysregulation is present before the emergence of motor symptoms and may contribute to disease development. By highlighting distinct patterns of inflammation-related and protective bacterial populations, the study supports ongoing exploration of the gut–brain axis in Parkinson’s and its potential as a target for early intervention.
Future research is needed to establish whether these microbiome alterations directly drive neurodegeneration or reflect secondary changes in disease progression. Nevertheless, the data underscore the importance of monitoring gut microbial signatures in at-risk populations such as those with isolated REM sleep behavior disorder.
Reference: Troci A et al. Differences in intestinal microbiota in Parkinson’s disease and isolated REM sleep behavior disorder. J Parkinsons Dis. 2025 Sep 12:1877718X251354931.
