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Lipids in Health and Disease Feb 2021Although imbalanced intestinal flora contributes to the pathogenesis of nonalcoholic fatty liver disease (NAFLD), conflicting results have been obtained for... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Although imbalanced intestinal flora contributes to the pathogenesis of nonalcoholic fatty liver disease (NAFLD), conflicting results have been obtained for patient-derived microbiome composition analyses. A meta-analysis was performed to summarize the characteristics of intestinal microbiota at the species level in NAFLD patients.
METHODS
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement, a completed search (last update: December 30, 2020) of databases was performed to identify eligible case-control studies detecting gut microbiota in NAFLD patients. The meta-analysis results are presented as the standard mean difference (SMD) and 95% confidence interval (CI). Bias controls were evaluated with the Newcastle-Ottawa Scale (NOS), funnel plot analysis, and Egger's and Begg's tests.
RESULTS
Fifteen studies (NOS score range: 6-8) that detected the gut microbiota in the stools of 1265 individuals (577 NAFLD patients and 688 controls) were included. It was found that Escherichia, Prevotella and Streptococcus (SMD = 1.55 [95% CI: 0.57, 2.54], 1.89 [95% CI: 0.02, 3.76] and 1.33 [95% CI: 0.62, 2.05], respectively) exhibited increased abundance while Coprococcus, Faecalibacterium and Ruminococcus (SMD = - 1.75 [95% CI: - 3.13, - 0.37], - 9.84 [95% CI: - 13.21, - 6.47] and - 1.84 [95% CI, - 2.41, - 1.27], respectively) exhibited decreased abundance in the NAFLD patients compared with healthy controls. No differences in the abundance of Bacteroides, Bifidobacterium, Blautia, Clostridium, Dorea, Lactobacillus, Parabacteroides or Roseburia were confirmed between the NAFLD patients and healthy controls.
CONCLUSIONS
This meta-analysis revealed that changes in the abundance of Escherichia, Prevotella, Streptococcus, Coprococcus, Faecalibacterium and Ruminococcus were the universal intestinal bacterial signature of NAFLD.
Topics: Bacteroides; Bifidobacterium; Case-Control Studies; Clostridium; Dysbiosis; Escherichia; Feces; Gastrointestinal Microbiome; Humans; Lactobacillus; Liver; Non-alcoholic Fatty Liver Disease; Prevotella; Streptococcus
PubMed: 33637088
DOI: 10.1186/s12944-021-01440-w -
Molecular Psychiatry Dec 2023A body of pre-clinical evidence shows how the gut microbiota influence brain functioning, including brain connectivity. Linking measures of brain connectivity to the gut...
A body of pre-clinical evidence shows how the gut microbiota influence brain functioning, including brain connectivity. Linking measures of brain connectivity to the gut microbiota can provide important mechanistic insights into the bi-directional gut-brain communication. In this systematic review, we therefore synthesized the available literature assessing this association, evaluating the degree of consistency in microbiota-connectivity associations. Following the PRISMA guidelines, a PubMed search was conducted, including studies published up to September 1, 2022. We identified 16 studies that met the inclusion criteria. Several bacterial genera, including Prevotella, Bacteroides, Ruminococcus, Blautia, and Collinsella were most frequently reported in association with brain connectivity. Additionally, connectivity of the salience (specifically the insula and anterior cingulate cortex), default mode, and frontoparietal networks were most frequently associated with the gut microbiota, both in terms of microbial diversity and composition. There was no discernible pattern in the association between microbiota and brain connectivity. Altogether, based on our synthesis, there is evidence for an association between the gut microbiota and brain connectivity. However, many findings were poorly replicated across studies, and the specificity of the association is yet unclear. The current studies show substantial inter-study heterogeneity in methodology and reporting, limiting the robustness and reproducibility of the findings and emphasizing the need to harmonize methodological approaches. To enhance comparability and replicability, future research should focus on further standardizing processing pipelines and employing data-driven multivariate analysis strategies.
Topics: Humans; Gastrointestinal Microbiome; Brain; Brain-Gut Axis; Connectome; Nerve Net
PubMed: 37479779
DOI: 10.1038/s41380-023-02146-4 -
Brain and Behavior Jun 2023Bipolar disorder (BD) is a mood disorder that affects millions worldwide. Up to half of the diagnosed patients are reported to not receive adequate treatment. This study... (Review)
Review
BACKGROUND
Bipolar disorder (BD) is a mood disorder that affects millions worldwide. Up to half of the diagnosed patients are reported to not receive adequate treatment. This study aims to assess the relationship between the gut-brain axis and BD and to discuss and compare the efficacy of varying methods of balancing gut microbiotas in BD.
METHODS
Using PubMed, Embase, and Google Scholar from November 2021 to February 2022, we found 5310 studies on gut microbiota and its relation to BD. Using our inclusion criteria, 5283 studies were excluded. A total of 27 full-text articles were assessed for eligibility. Also, 12 articles that met our criteria and eligibility criteria reported on 613 BD patients.
RESULTS
Most studies analyzed found an overall difference in gut microbiota composition in bipolar patients compared to healthy controls, though the alterations found were not consistent. Differences in Lactobacillus, Faecalibacterium, and Ruminococcus abundance in BD compared to controls were found to be the most consistent across a few of the studies, but their effects on the gut-brain axis conflicted. Probiotic supplementation was found to lower patient rehospitalizations and significantly improve depressive symptoms and cognitive impairments among patients with BD.
CONCLUSIONS
Multiple studies included in this review point toward a possible link between BD and the gut microbiota. Probiotic supplements and other gut-balancing therapies could serve as effective adjunctive methods for the treatment of BD. Notable limitations of the studies included for analysis were small sample sizes and majority observational study designs. Furthermore, the microbiota aberrations found in patients with BD were not consistent across multiple studies. Despite these limitations, our findings demonstrate the need for further research regarding the relationship between aberrant gut microbiota profiles and BD, as well as the effectiveness of gut balancing methods as adjunctive treatments.
Topics: Humans; Bipolar Disorder; Gastrointestinal Microbiome; Brain-Gut Axis; Observational Studies as Topic
PubMed: 37127945
DOI: 10.1002/brb3.3037 -
Genes & Nutrition Jan 2022Previous observational studies have demonstrated inconsistent and inconclusive results of changes in the intestinal microbiota in patients with obesity and metabolic... (Review)
Review
BACKGROUND
Previous observational studies have demonstrated inconsistent and inconclusive results of changes in the intestinal microbiota in patients with obesity and metabolic disorders. We performed a systematic review to explore evidence for this association across different geography and populations.
METHODS
We performed a systematic search of MEDLINE (OvidSP) and Embase (OvidSP) of articles published from Sept 1, 2010, to July 10, 2021, for case-control studies comparing intestinal microbiome of individuals with obesity and metabolic disorders with the microbiome of non-obese, metabolically healthy individuals (controls). The primary outcome was bacterial taxonomic changes in patients with obesity and metabolic disorders as compared to controls. Taxa were defined as "lean-associated" if they were depleted in patients with obesity and metabolic disorders or negatively associated with abnormal metabolic parameters. Taxa were defined as "obesity-associated" if they were enriched in patients with obesity and metabolic disorders or positively associated with abnormal metabolic parameters.
RESULTS
Among 2390 reports screened, we identified 110 full-text articles and 60 studies were included. Proteobacteria was the most consistently reported obesity-associated phylum. Thirteen, nine, and ten studies, respectively, reported Faecalibacterium, Akkermansia, and Alistipes as lean-associated genera. Prevotella and Ruminococcus were obesity-associated genera in studies from the West but lean-associated in the East. Roseburia and Bifidobacterium were lean-associated genera only in the East, whereas Lactobacillus was an obesity-associated genus in the West.
CONCLUSIONS
We identified specific bacteria associated with obesity and metabolic disorders in western and eastern populations. Mechanistic studies are required to determine whether these microbes are a cause or product of obesity and metabolic disorders.
PubMed: 35093025
DOI: 10.1186/s12263-021-00703-6 -
Journal of Zhejiang University.... Dec 2022: Osteoporosis (OP) has become a major public health issue, threatening the bone health of middle-aged and elderly people from all around the world. Changes in the gut... (Meta-Analysis)
Meta-Analysis
: Osteoporosis (OP) has become a major public health issue, threatening the bone health of middle-aged and elderly people from all around the world. Changes in the gut microbiota (GM) are correlated with the maintenance of bone mass and bone quality. However, research results in this field remain highly controversial, and no systematic review or meta-analysis of the relationship between GM and OP has been conducted. This paper addresses this shortcoming, focusing on the difference in the GM abundance between OP patients and healthy controls based on previous 16S ribosomal RNA (rRNA) gene sequencing results, in order to provide new clinical reference information for future customized prevention and treatment options of OP. : According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), we comprehensively searched the databases of PubMed, Web of Science, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI). In addition, we applied the R programming language version 4.0.3 and Stata 15.1 software for data analysis. We also implemented the Newcastle-Ottawa Scale (NOS), funnel plot analysis, sensitivity analysis, Egger's test, and Begg's test to assess the risk of bias. : This research ultimately considered 12 studies, which included the fecal GM data of 2033 people (604 with OP and 1429 healthy controls). In the included research papers, it was observed that the relative abundance of and increased in the OP group, while the relative abundance for of Bacteroidetes increased (except for Ireland). Meanwhile, Firmicutes, , , , and showed reduced relative abundance in Chinese studies. In the linear discriminant analysis Effect Size (LEfSe) analysis, certain bacteria showed statistically significant results consistently across different studies. : This observational meta-analysis revealed that changes in the GM were correlated with OP, and variations in some advantageous GM might involve regional differences.
Topics: Aged; Humans; Middle Aged; Feces; Gastrointestinal Microbiome; Genes, rRNA; Osteoporosis; RNA, Ribosomal, 16S
PubMed: 36518053
DOI: 10.1631/jzus.B2200344 -
Journal of Clinical GastroenterologyAnimal studies have highlighted how the microbiota acts in a sex-specific manner with sex hormones demonstrating an association with the composition and diversity of the...
GOALS/BACKGROUND
Animal studies have highlighted how the microbiota acts in a sex-specific manner with sex hormones demonstrating an association with the composition and diversity of the microbiota. This systematic review aimed to gather the available scientific evidence to explore the association between sex hormones and gut microbiota composition and diversity, in humans.
STUDY
Four bibliographic databases were searched in July 2020 using terms related to "microbiota," "microflora," "sex hormones," "testosterone," and "estrogen." Human studies that investigated the correlation between sex hormones and the microbiota composition or diversity using next-generation sequencing were included.
RESULTS
A total of 10,468 records were screened with 13 studies included in this review. In healthy women, higher estrogen levels were found to be associated with a higher abundance of Bacteroidetes, a lower abundance of Firmicutes, the Ruminococcaceae family and increased diversity. In healthy men, raised testosterone levels positively correlated with Ruminococcus, Acinetobacter, and an increased microbial diversity. Escherichia and Shigella spp. were correlated with raised testosterone in healthy women whereas Ruminococcus spp. was negatively associated with elevated testosterone levels. Women with altered testosterone/estrogen profiles (such as in polycystic ovary syndrome), had a differing gut microbiota compared with healthy women.
CONCLUSIONS
The findings gathered highlight an association between sex hormones and the gut microbiota composition/diversity and may contribute to the sex-based variations observed in disease pathogenesis. Factors such as age and medical conditions are implicated in the associations observed and should be accounted for in future studies. As the understanding of the complex symbiotic relationship between humans and their gut microbiota increases, microbiota modulation could be an attractive option for the prevention and treatment of gastrointestinal disorders.
Topics: Animals; Estrogens; Feces; Female; Gastrointestinal Microbiome; Gonadal Steroid Hormones; Humans; Male; Polycystic Ovary Syndrome; Testosterone
PubMed: 35283442
DOI: 10.1097/MCG.0000000000001676 -
Journal of Clinical Medicine Mar 2021The response of patients with inflammatory bowel disease (IBD) to fecal microbial transplantation (FMT) has been inconsistent possibly due to variable engraftment of... (Review)
Review
Repeated Fecal Microbial Transplantations and Antibiotic Pre-Treatment Are Linked to Improved Clinical Response and Remission in Inflammatory Bowel Disease: A Systematic Review and Pooled Proportion Meta-Analysis.
The response of patients with inflammatory bowel disease (IBD) to fecal microbial transplantation (FMT) has been inconsistent possibly due to variable engraftment of donor microbiota. This failure to engraft has resulted in the use of several different strategies to attempt optimization of the recipient microbiota following FMT. The purpose of our study was to evaluate the effects of two distinct microbial strategies-antibiotic pre-treatment and repeated FMT dosing-on IBD outcomes. A systematic literature review was designed and implemented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A medical librarian conducted comprehensive searches in MEDLINE, Embase, Scopus, Web of Science Core Collection, and Cochrane Library on 25 November 2019 and updated on 29 January 2021. Primary outcomes of interest included comparing relapse and remission rates in patients with IBD for a single FMT dose, repeated FMT dosages, and antibiotic pre-treatment groups. Twenty-eight articles (six randomized trials, 20 cohort trials, two case series) containing 976 patients were identified. Meta-analysis revealed that both repeated FMT and antibiotic pre-treatment strategies demonstrated improvements in pooled response and remission rates. These clinical improvements were associated with increases in fecal microbiota richness and α-diversity, as well as the enrichment of several short-chain fatty acid (SCFA)-producing anaerobes including , , , , , and related species.
PubMed: 33804464
DOI: 10.3390/jcm10050959 -
The American Journal of Chinese Medicine 2021Based on the study and research on the pathogenesis of colorectal cancer, the types and functions of gut microbiota, and its role in guiding and regulating the...
Based on the study and research on the pathogenesis of colorectal cancer, the types and functions of gut microbiota, and its role in guiding and regulating the occurrence and development of diseases, we have explored the mechanism of traditional Chinese medicine in the treatment of colorectal cancer by regulating the gut microbiota. Genetic variation, abnormal responses of innate and adaptive immunity, mucosal barrier dysfunction, imbalance of intestinal microbial colonization, personal and environmental risk factors are the main pathogenesis of colorectal cancer. The gut microbiota mainly includes (including , , and ) and (including and ), which have biological antagonism, nutrition for the organism, metabolic abilities, immune stimulation, and ability to shape cancer genes functions to body. The gut microbiota can be related to the health of the host. Current studies have shown that Chinese herbal compound, single medicinal materials, and monomer components can treat colorectal cancer by regulating the gut microbiota, such as Xiaoyaosan can increase the abundance of , , and and decrease the abundance of and . Therefore, studying the regulation and mechanism of gut microbiota on colorectal cancer is of great benefit to disease treatment.
Topics: Colorectal Neoplasms; Gastrointestinal Microbiome; Humans; Medicine, Chinese Traditional; Risk Factors
PubMed: 33827382
DOI: 10.1142/S0192415X21500385 -
The Journal of Nutrition, Health & Aging 2023Obesity in the older adults is a health concern that increases the risk of several life-threatening diseases. Previous research has been revealed that alterations in the...
BACKGROUND
Obesity in the older adults is a health concern that increases the risk of several life-threatening diseases. Previous research has been revealed that alterations in the gut microbiota composition is related to obesity. So, understanding the gut microbiota changes in older adults' obesity may help to provide promising strategies for their health management.
OBJECTIVES
Here we conducted a systematic review that investigate the alteration of gut microbiota composition in association with obesity and its indices in the older adults.
DESIGN
Systematic review.
SETTING
A comprehensive systematic search was performed through PubMed, Web of Science, Scopus and Embase databases for all relative studies up to 2023 with the main search concepts as Microbiota, Obesity and Elderly. The data about gut microbiota in association with obesity indices had been extracted.
PARTICIPANTS
Older adults (≥60 years).
INTERVENTION
None.
MEASUREMENTS
None.
RESULTS
Within 10741 recordes, 11 studies met the inclusion criteria and were included in this systematic review. Most of them indicated the gut microbiota alterations in obese compared with non-obese older adults. However, the gut microbiome composition in obese older adults is affected by other underlying diseases like diabetes and metabolic syndrome. The most important taxa that had abundance alteration in association with obesity in older adults were Christensenellaceae, Porphyromonadaceae and Rikenellaceae, Akkermansia, Blautia, Prevotella, Ruminococcus, Bacteroides and Faecalibacterium.
CONCLUSION
The gut microbiota composition is associated with obesity in older adults. Considering the other factors affecting the composition of gut microbiota, such as age, underlying diseases and lifestyle, a more accurate conclusion about this matter requires more future studies.
Topics: Humans; Aged; Gastrointestinal Microbiome; Obesity; Microbiota; Metabolic Syndrome; Diabetes Mellitus
PubMed: 37960904
DOI: 10.1007/s12603-023-1988-8 -
Advances in Rheumatology (London,... Jul 2021Systemic Lupus Erythematosus (SLE) is an autoimmune disease, characterized by being multi-systemic and, therefore, reaching various organs and affecting mainly young...
BACKGROUND
Systemic Lupus Erythematosus (SLE) is an autoimmune disease, characterized by being multi-systemic and, therefore, reaching various organs and affecting mainly young women. Its pathogenesis comprehends many factors, including the interaction between microbiota and immune system. This systematic review assessed the relationship between intestinal microbiota and SLE in activity, highlighting microbiota representative patterns regarding quantity and diversity.
METHODS
This study considered researches carried out in patients with SLE, with no restriction of age or gender, which fulfilled the classification criteria of either Systemic Lupus International Collaborating Clinic (SLICC), American College of Rheumatology (ACR) or European League Against Rheumatism (EULAR) and used the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) to classify disease in activity or remission were included. The search was carried out from October, 2020 to January, 2021 using the following databases: Medline via Pubmed, Scopus, and Embase. Five papers were included with a total of 288 participants with SLE.
RESULTS
Regarding microbiota in patients with SLE in activity, there was significant increase in the following genera: Lactobacillus, Streptococcus, Megasphaera, Fusobacterium, Veillonella, Oribacterium, Odoribacter, Blautia, and Campylobacter. On the other hand, decrease in Faecalibacterium and Roseburia genera as well as Ruminococcus gnavus species was observed in remission cases, showing differences between the microbiota profile in SLE in activity and in remission.
CONCLUSIONS
Results suggest that dysbiosis may be involved in the disease activity process.
TRIAL REGISTRATION
CRD42021229322 .
Topics: Gastrointestinal Microbiome; Humans; Lupus Erythematosus, Systemic
PubMed: 34215348
DOI: 10.1186/s42358-021-00201-8