Background. Considering the observed role of probiotics in modulating gut microbiome, probiotics are discussed to be one potential complementary therapy for obesity management in recent years. The aim of the present study was to systematically review the meta-analyses of controlled trials and investigate the effects of probiotics on obesity. Methods. A comprehensive search was conducted on PubMed, Web of Science, and Cochrane Library web databases up to May 2020. Inclusion criteria were meta-analyses of controlled trials which evaluated the impact of probiotics on obesity in English language. Meta-analyses done on pregnant women, children, animal studies, or the effect of prebiotics on anthropometric indices were excluded. Results. Within 325 recorded studies, 20 studies met the inclusion criteria consisting of 16676 overweight/obese adults with different underlying disorders such as nonalcoholic fatty liver disease (NAFLD), or polycystic ovary syndrome (PCOS). The length of intervention varied from 2 to 26 weeks. Results of meta-analyses have shown a moderate effect of probiotics on body weight in overweight/obese adults: from −0.526 kg/m2 (95% CI: −0.810, −0.247) to −0.25 kg/m2 (95% CI: −0.33, −0.17). Body mass index (BMI) was changed from −1.46 kg/m2 (95% CI: −2.44, −0.48) to −1.08 kg/m2 (95% CI: −2.05, −0.11) in NAFLD. Probiotics could reduce BMI from −0.36 kg/m2 (95% CI: −0.74, 0.02) to −0.29 kg/m2 (95% CI: −0.54, −0.03) in patients with PCOS. Conclusion. It seems that the probiotic products could have beneficial effects as an adjunct therapy for care and management of obesity when used in high dose. However, due to heterogeneity of included studies, it is required to confirm our results by more meta-analyses of clinical trials.

Objective: The main goal of this systematic review is to summarize evidences regarding alterations of microbial composition in ADHD cases and uncover underlying mechanisms. Methods: A comprehensive search was conducted on PubMed, Web of Science, and Scopus databases up to March 2021. All the observational studies including case-control, cross-sectional, and cohorts investigating the correlations between the gut microbiota and ADHD in both adults and children were included. Results: We found eight eligible studies. Enterococcus, Bifidobacterium, and Odoribacter were increased which may lead to impaired dopamine related functions in CNS. Moreover, decrease of Faecalibacterium frequency in ADHD could result in higher permeability and crossing of inflammatory cytokines. Regarding the short chain fatty acids-producing bacteria, Ruminococcaceae family decreased and Bacteroides uniformis and Bacteroides ovatus species increased. Conclusion: Gut microbiota correlation with ADHD and its underlying mechanisms could open new windows for developing novel therapies of ADHD by manipulating microbiota.

Objective Different mechanisms play role in the pathogenesis of gout and gut microbiota is believed to be one of these factors. The main goal of this systematic review is to summarize evidence regarding changes in gut microbiota composition in gout disease and uncover underlying mechanisms. Methods A comprehensive search was conducted on PubMed, Web of Science and Scopus databases up to October 2021. Animal studies and human observational studies including case-control, cross-sectional, and cohorts assessing associations between the gut microbiota composition and gout were included. The quality of the included human and animal studies has been evaluated using the Newcastle–Ottawa Quality Assessment scale (NOS) and the SYRCLE's risk of bias tool, respectively. Results 15 studies from 274 recorded studies were included in this systematic review. 10 studies on human and 5 on animals. Increase in frequency of Alistipes and decreased Enterobacteriaceae lead to changes of enzyme level in purine metabolism and aggravates gout condition. Moreover, rise of Phascolarctobacterium and Bacteroides play role in gout through enzyme modulation. Butyrate-producing bacteria such as Faecalibacterium, prausnitzii, Oscillibacter, Butyricicoccus and Bifidobacterium revealed an increase in healthy controls compared to gout patients which points to the possible underlying role of short-chain fatty acids (SCFAs) leading to both anti-inflammatory advantages and promoting intestinal barrier for host. Lipopolysaccharides (LPS)-releasing bacteria, Enterobacteriaceae, Prevotella and Bacteroides, also impact on gout disease by stimulating the innate immune system. Conclusion Exploring gut microbiota dysbiosis in gout disease and the underlying mechanisms could make a novel insight for microbiota-modulating therapies.

ObjectivesGut dysbiosis is believed to be one of the several mechanisms that are involved in the pathogenesis of gout. This systematic review aimed to summarize the role of gut dysbiosis in gout disease and uncover the underlying mechanisms.MethodsA comprehensive search was conducted on PubMed, Web of Science, and Scopus databases up to October 2021. Animal studies and human observational studies, including case-control, cross-sectional, and cohort studies assessing the association between gut microbiota composition and gout were included. The quality of included studies has been evaluated using the Newcastle–Ottawa Quality Assessment scale (NOS) and the SYRCLE's risk of bias tool.ResultsInitially, we found 274 studies among which 15 studies were included in this systematic review. Of them, 10 studies were conducted on humans and 5 studies were conducted on animals. Increased abundance of Alistipes and decreased abundance of Enterobacteriaceae alters purine metabolism, thereby aggravating gout condition. Moreover, a higher abundance of Phascolarctobacterium and Bacteroides in gout modulates enzymatic activity in purine metabolism. Butyrate-producing bacteria such as Faecalibacterium, prausnitzii, Oscillibacter, Butyricicoccus, and Bifidobacterium have higher abundance in healthy controls compared to gout patients, suggesting the anti-inflammatory and anti-microbial role of short-chain fatty acids (SCFAs). Lipopolysaccharides (LPS)-releasing bacteria, such as Enterobacteriaceae, Prevotella, and Bacteroides, are also involved in the pathogenesis of gout disease by stimulating the innate immune system.ConclusionExploring the role of gut dysbiosis in gout and the underlying mechanisms can help develop microbiota-modulating therapies for gout.