Probiotics treatment for Parkinson disease: a systematic review and meta-analysis of clinical trials

Abstract

Background and aims: People with Parkinson disease (PwP) exhibit gut dysbiosis and considerable gastrointestinal (GI) symptoms. Probiotics, beneficial strains of microorganisms, supplement and optimize the intestinal environment and alleviate GI symptoms among elderly people. We conducted a systematic review and metaanalysis of clinical trials to investigate the effects of probiotics on PwP. Methods: We searched the PubMed, Embase, and Cochrane Library databases. Major outcomes were the effects on GI symptoms, including bowel movement and stool characteristics. This study was registered with PROSPERO (CRD42021262036). Results: Six randomized controlled trials (RCTs) and two open-label studies were included. Most of the probiotic regimens were based on Lactobacillus and Bifidobacterium. Six studies investigated the benefit of probiotics for GI symptoms, especially for PwP with functional constipation, and two RCTs assessed probiotics' effect on systematic metabolism and inflammation. In the meta-analysis, probiotic treatment significantly increased the frequency of bowel movements among PwP (mean difference [MD]: 1.06 /week, 95% confidence interval [CI]: 0.61 to 1.51, p < 0.001, I 2 = 40%). Additionally, probiotic treatment significantly normalized stool consistency (standard MD: 0.61, 95% CI = 0.31 to 0.91, p < 0.001, I 2 = 0%). Conclusions: Although the probiotic compositions varied, probiotic treatment significantly attenuated constipation for PwP and exhibited possible systematic effects on inflammation and metabolism. Given the tolerability of probiotics, the present meta-analysis may provide more consolidated evidence of the benefit of probiotics on constipation in PwP and a possible new therapeutic approach for disease modification.

Meta-analysis of randomized controlled trials of the effects of probiotics in Parkinson's disease

“…Interestingly, two RCTs that examined the use of laxatives during probiotic intake in patients with PD found that probiotic intake significantly decreased the use of laxatives (SMD = −0.27; 95% CI, −0.53, −0.01; P < 0.04; I 2 = 15%). A previous meta-analysis that included three RCTs also revealed that oral supplementation with probiotics markedly increased the frequency of bowel movements (mean difference [MD]:1.06 per week, 95% CI:0.61 to 1.51, p < 0.001, I 2 = 40%) and improved stool consistency (standard MD:0.61, 95% CI = 0.31 to 0.91, p < 0.001, I 2 = 0%), 22 which is consistent with the findings of our meta-analysis. The effects of probiotics on functional constipation in adults without PD have been extensively investigated.…”

“…Currently, as far as we know, we only found a similar meta-analysis, but this study only included three RCTs. 22 The certainty of evidence was graded as very low. Therefore, in this study, we performed a meta-analysis of RCTs to examine the effects of probiotics in patients with PD.…”

Therapeutics for neurodegenerative diseases by targeting the gut microbiome: from bench to bedside

“…Tamtaji et al identified that probiotics ( Lactobacillus acidophilus , Bifidobacterium bifidum , and Bifidobacterium longum , 2 × 10 9 CFU/day) combined with selenium supplementation significantly enhanced cognitive function compared to selenium or placebo alone in AD patients [ 126 ]. Administration of probiotic Lactobacillus and Bifidobacterium strains alleviated both constipation symptoms and motor symptoms in PD patients [ 127 , 128 ]. However, a meta-analysis that included trials investigating the effects of probiotics, mainly Lactobacillus and Bifidobacterium , did not find any beneficial effects on cognitive function in diagnosed AD patients [ 129 ].…”

Microbiota and probiotics: chances and challenges – a symposium report

“…In vivo studies report improved glucose metabolism, reduced inflammation, and neurodegeneration (Leta et al, 2021). In a review of eight clinical trials in PD patients given lactobacilli or bifidobacteria probiotics (Hong et al, 2022), constipation was significantly reduced, and modest anti-inflammatory effects were observed. A downside of using probiotics in PD is the potential for probiotic-drug interactions since bacterial decarboxylases may affect the bioavailability of -dopamine, a Carbidopa component commonly used to manage PD neurological symptoms (van Kessel et al, 2019).…”