RESUMO
Background: It has been suggested in several observational studies that migraines are associated with the gut microbiota. It remains unclear, however, how the gut microbiota and migraines are causally related. Methods: We performed a bidirectional two-sample mendelian randomization study. Genome-wide association study (GWAS) summary statistics for the gut microbiota were obtained from the MiBioGen consortium (n = 18,340) and the Dutch Microbiota Project (n = 7,738). Pooled GWAS data for plasma metabolites were obtained from four different human metabolomics studies. GWAS summary data for migraine (cases = 48,975; controls = 450,381) were sourced from the International Headache Genetics Consortium. We used inverse-variance weighting as the primary analysis. Multiple sensitivity analyses were performed to ensure the robustness of the estimated results. We also conducted reverse mendelian randomization when a causal relationship between exposure and migraine was found. Results: LachnospiraceaeUCG001 (OR = 1.12, 95% CI: 1.05-1.20) was a risk factor for migraine. Blautia (OR = 0.93, 95% CI: 0.88-0.99), Eubacterium (nodatum group; OR = 0.94, 95% CI: 0.90-0.98), and Bacteroides fragilis (OR = 0.97, 95% CI: 0.94-1.00) may have a suggestive association with a lower migraine risk. Functional pathways of methionine synthesis (OR = 0.89, 95% CI: 0.83-0.95) associated with microbiota abundance and plasma hydrocinnamate (OR = 0.85, 95% CI: 0.73-1.00), which are downstream metabolites of Blautia and Bacteroides fragilis, respectively, may also be associated with lower migraine risk. No causal association between migraine and the gut microbiota or metabolites was found in reverse mendelian randomization analysis. Both significant horizontal pleiotropy and significant heterogeneity were not clearly identified. Conclusion: This Mendelian randomization analysis showed that LachnospiraceaeUCG001 was associated with an increased risk of migraine, while some bacteria in the gut microbiota may reduce migraine risk. These findings provide a reference for a deeper comprehension of the role of the gut-brain axis in migraine as well as possible targets for treatment interventions.
RESUMO
Background: Cell transplants as a treatment for Parkinson's disease have been studied for decades, and stem cells may be the most promising cell sources for this treatment. We aimed to investigate whether stem cell transplantation contributes to the cure for Parkinson's disease and the factors that may influence the efficacy for this therapy. Methods: PubMed, Embase, Cochrane Library, Web of Science, SinoMed, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and ChinaInfo were thoroughly searched to find controlled trials or randomized controlled trials performing stem cell transplantation in patients with Parkinson's disease. The pooled effects were analyzed to evaluate the weighted mean difference (WMD) with 95% confidence intervals. Results: Nine articles were identified including 129 individuals. Stem cell transplantation was an effective treatment for Parkinson's disease (WMD = -14.86; 95% CI: -16.62 to -13.10; p < 0.00001), with neural stem cells, umbilical cord mesenchymal stem cells (UCMSCs), and bone marrow mesenchymal stem cells (BMMSCs) being effective cell sources for transplantation. Stem cell transplantation can be effective for at least 12 months, but its long-term effectiveness remains unknown due to the limited studies monitoring patients for more than 1 year, not to mention decades. Conclusion: Data from controlled trials suggest that stem cell transplantation as a therapy for Parkinson's disease can be effective for at least 12 months. The factors that may influence its curative effect are time after transplantation and stem cell types. Systematic review registration: (Registration ID: CRD42022353145).
