Retrospective analysis of diet and gut microbiota diversity and clinical pharmacology outcomes in patients with Parkinsonism syndrome.

Background: Parkinson's disease (PD) is a global neurodegenerative ailment impacting millions, causes significant degeneration of dopaminergic neurons in the substantia nigra. Emerging research underscores the gut microbiota's role in PD onset. Yet, investigations in Chinese demographics are lacking. This study thus targets a retrospective examination of gut microbiota variety and clinical aspects in Chinese PD patients. Methods: We retrospectively analyzed 50 PD patients' clinical data (admitted May 2021-April 2022) and compared their gut microbiota composition and abundance via 16S rDNA V3-V4 region sequencing against 50 healthy controls. The study also explored links between disease severity and PD patients' gut microbiota. Results: We found that the gut microbiota diversity was increased in PD patients. Specifically, phyla Firmicutes, Actinobacteria, and Proteobacteria were more abundant, whereas Bacteroidetes was less abundant compared to controls. Gut microbiota diversity did not vary between early-vs. late-onset PD, tremor-dominant vs. non-tremor-dominant, or constipation-associated vs. non-constipation-associated subtypes. The abundance of Firmicutes was positively correlated with UPDRS (Unified Parkinson's Disease Rating Scale) III score, NMSS (Non-Motor Symptoms Scale) score, Wexner score, and PDQ-39 (Parkinson's Disease Questionnaire-39) score; the abundance of Actinobacteria was positively correlated with UPDRS III, NMSS, Wexner, and PDQ-39 scores; and the abundance of Bacteroidetes was negatively correlated with UPDRS III, NMSS, Wexner, and PDQ-39 scores. At the family level, the abundance of Bifidobacteriaceae, Enterobacteriaceae, and Porphyromonadaceae was positively correlated with UPDRS III, NMSS, and PDQ-39 scores. Conclusion: Compared with healthy individuals, PD patients have increased gut microbiota diversity, and the abundance of Bifidobacteriaceae, Enterobacteriaceae, and Porphyromonadaceae is associated with the severity of both motor and non-motor symptoms in PD patients.