In a randomized trial of 105 Parkinson's patients with constipation, adjunct Bifidobacterium animalis subsp. lactis combined with Liuwei'anxiao Capsule improved bowel movement frequency, stool form, patient-reported constipation scores and achieved a higher overall response rate versus either…

This study offers a clinically actionable, microbiome-modulating adjunct therapy for a common and quality-of-life–limiting PD nonmotor symptom, supporting the gut–brain axis as a translational target and motivating follow-up trials to assess effects on broader PD outcomes or disease progression.

ETHNOPHARMACOLOGICAL RELEVANCE: Liuwei'anxiao Capsule (LAC), a well-established Chinese patent medicine (CPM) that derived from the Mongolian and Tibetan folk prescription "Liuwei Anxiao San", has demonstrated efficacy in treating constipation but can cause side effects when used improperly. Probiotics offer a promising adjunct to enhance CPM efficacy and safety while minimizing their side effects. AIM OF THE STUDY: In this clinical trial, a probiotic strain Bifidobacterium animalis subsp. lactis BAMA-B06/BAu-B0111 was employed to potentiate the efficacy of LAC in relieving Parkinson's disease (PD) constipation, a common non-motor symptom significantly reducing quality of life and potentially exacerbating disease progression in PD patients. MATERIALS AND METHODS: A total of 105 PD patients with constipation were ultimately randomized into three groups: LAC alone (L group), probiotic of B. animalis subsp. lactis alone (P group), and the combination (LP group). Motor symptoms were assessed using the Hoehn and Yahr scale and the Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III at baseline and post-treatment. Constipation severity was evaluated using weekly spontaneous bowel movement (SBM) frequency, Bristol Stool Scale (BSS) scores, Wexner Constipation Score, Patient Assessment of Constipation Quality of Life (PAC-QOL) questionnaire, and the total effective rate of symptom improvement. Additionally, gut microbiota composition was analyzed by 16S rRNA high-throughput sequencing. RESULTS: All groups showed significant improvements in Wexner and PAC-QOL scores and increased weekly SBM frequency (P < 0.001). In addition, LAC and combination therapy notably improved stool morphology, as indicated by the BSS scores. And the overall effective rates of constipation improvement were 60.00%, 56.67%, and 72.41% for the L, P, and LP groups, respectively. The LP group significantly restored the relative abundance of Bifidobacterium, Megamonas, and Roseburia that were closely associated with the improved clinical outcomes, indicating a potential gut microbiota-mediated mechanism underlying the improved efficacy of combining therapy. CONCLUSION: The adjunct use of probiotics contributed to the better therapeutic efficacy of LAC in alleviating constipation symptoms via modulating the gut microbiota in PD patients, suggesting a beneficial combined application of LAC and probiotic in managing PD-related constipation.