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Frontiers in Endocrinology 2021Autoimmune thyroid disease (AITD) is characterized by thyroid dysfunction and deficits in the autoimmune system. Growing attention has been paid toward the field of gut... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Autoimmune thyroid disease (AITD) is characterized by thyroid dysfunction and deficits in the autoimmune system. Growing attention has been paid toward the field of gut microbiota over the last few decades. Several recent studies have found that gut microbiota composition in patients with AITD has altered, but no studies have conducted systematic reviews on the association between gut microbiota and ATID.
METHODS
We searched PubMed, Web of Science, Embase, and Cochrane databases without language restrictions and conducted a systematic review and meta-analysis of eight studies, including 196 patients with AITD.
RESULTS
The meta-analysis showed that the alpha diversity and abundance of certain gut microbiota were changed in patients with AITD compared to the controls. Chao1,the index of the microflora richness, was increased in the Hashimoto's thyroiditis group compared to controls (SMD, 0.68, 95%CI: 0.16 to 1.20), while it was decreased in the Graves' disease group (SMD, -0.87, 95%CI: -1.46 to -0.28). In addition, we found that some beneficial bacteria like and were decreased in the AITD group, and harmful microbiota like was significantly increased compared with the controls. Furthermore, the percentage of relevant abundance of other commensal bacteria such as , , and was increased compared with the controls.
CONCLUSIONS
This meta-analysis indicates an association between AITD and alteration of microbiota composition at the family, genus, and species levels.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO, identifier CRD42021251557.
Topics: Case-Control Studies; Dysbiosis; Gastrointestinal Microbiome; Graves Disease; Hashimoto Disease; Humans; Risk Factors; Thyroiditis, Autoimmune
PubMed: 34867823
DOI: 10.3389/fendo.2021.774362 -
Cureus Oct 2022Deaths from colorectal cancer (CRC) are still rising, and various links to etiology have been proposed. However, a direct link between microbial dysbiosis and colorectal... (Review)
Review
Deaths from colorectal cancer (CRC) are still rising, and various links to etiology have been proposed. However, a direct link between microbial dysbiosis and colorectal cancer has not been postulated. This study aimed to identify the role of microbes in the pathogenesis of colorectal cancer. This systematic review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search was done considering papers published over the past 12 years, using PubMed, PubMed Central, Cochrane, Google Scholar, and ScienceDirect databases. Studies were selected based on the following predefined eligibility criteria: English-language systematic reviews, meta-analysis, randomized controlled trials (RCTs), and clinical trials, which included papers on microbes playing roles in colorectal cancer with the derived data transferred to a template. Following this, quality assessment was done using each study's relevant assessment tool. The initial search generated 128 studies. From the study, we found the ratio of , when compared between healthy and colorectal cancer patients' guts, was the highest, although it was not the most predominant gut organism. Enterotoxigenic (ETBF), and , and showed links with colorectal cancer and described pathways that could explain its implication in colorectal cancer. However, overt conclusions cannot be drawn because further research needs to be conducted.
PubMed: 36465770
DOI: 10.7759/cureus.30893 -
Neoplasia (New York, N.Y.) Jul 2022Enterotoxigenic Bacteroides fragilis (ETBF) has received significant attention for a possible association with, or causal role in, colorectal cancer (CRC). The goal of...
Enterotoxigenic Bacteroides fragilis (ETBF) has received significant attention for a possible association with, or causal role in, colorectal cancer (CRC). The goal of this review was to assess the status of the published evidence supporting (i) the association between ETBF and CRC and (ii) the causal role of ETBF in CRC. PubMed and Scopus searches were performed in August 2021 to identify human, animal, and cell studies pertaining to the role of ETBF in CRC. Inclusion criteria included the use of cell lines, mice, exposure to BFT or ETBF, and detection of bft. Review studies were excluded, and studies were limited to the English language. Quality of study design and risk of bias analysis was performed on the cell, animal, and human studies using ToxRTools, SYRCLE, and NOS, respectively. Ninety-five eligible studies were identified, this included 22 human studies, 24 animal studies, 43 cell studies, and 6 studies that included both cells and mice studies. We found that a large majority of studies supported an association or causal role of ETBF in CRC, as well as high levels of study bias was detected in the in vitro and in vivo studies. The high-level heterogeneity in study design and reporting made it difficult to synthesize these findings into a unified conclusion, suggesting that the need for future studies that include improved mechanistic models, longitudinal in vitro and in vivo evidence, and appropriate control of confounding factors will be required to confirm whether ETBF has a direct role in CRC etiopathogenesis.
Topics: Animals; Humans; Mice; Bacterial Toxins; Bacteroides fragilis; Bacteroides Infections; Colorectal Neoplasms
PubMed: 35461079
DOI: 10.1016/j.neo.2022.100797 -
World Journal of Surgical Oncology Dec 2019Growing evidence supports the role of the intestinal microbiome in the carcinogenesis of colorectal cancers, but its impact on colorectal cancer surgery outcomes is not...
OBJECTIVES
Growing evidence supports the role of the intestinal microbiome in the carcinogenesis of colorectal cancers, but its impact on colorectal cancer surgery outcomes is not clearly defined. This systematic review aimed to analyze the association between intestinal microbiome composition and postoperative complication and survival following colorectal cancer surgery.
METHODS
A systematic review was conducted according to the 2009 PRISMA guidelines. Two independent reviewers searched the literature in a systematic manner through online databases, including Medline, Scopus, Embase, Cochrane Oral Health Group Specialized Register, ProQuest Dissertations and Theses Database, and Google Scholar. Human studies investigating the association between the intestinal microbiome and the short-term (anastomotic leakage, surgical site infection, postoperative ileus) and long-term outcomes (cancer-specific mortality, overall and disease-free survival) of colorectal cancer surgery were selected. Patients with any stage of colorectal cancer were included. The Newcastle-Ottawa scale for case-control and cohort studies was used for the quality assessment of the selected articles.
RESULTS
Overall, 8 studies (7 cohort studies and 1 case-control) published between 2014 and 2018 were included. Only one study focused on short-term surgical outcomes, showing that anastomotic leakage is associated with low microbial diversity and abundance of Lachnospiraceae and Bacteroidaceae families in the non-cancerous resection lines of the stapled anastomoses of colorectal cancer patients. The other 7 studies focused on long-term oncological outcomes, including survival and cancer recurrence. The majority of the studies (5/8) found that a higher level of Fusobacterium nucleatum adherent to the tumor tissue is associated with worse oncological outcomes, in particular, increased cancer-specific mortality, decreased median and overall survival, disease-free and cancer-specific survival rates. Also a high abundance of Bacteroides fragilis was found to be linked to worse outcomes, whereas the relative abundance of the Prevotella-co-abundance group (CAG), the Bacteroides CAG, and the pathogen CAG as well as Faecalibacterium prausnitzii appeared to be associated with better survival.
CONCLUSIONS
Based on the limited available evidence, microbiome composition may be associated with colorectal cancer surgery outcomes. Further studies are needed to elucidate the role of the intestinal microbiome as a prognostic factor in colorectal cancer surgery and its possible clinical implications.
Topics: Anastomotic Leak; Colorectal Neoplasms; Colorectal Surgery; Gastrointestinal Microbiome; Humans; Postoperative Complications; Prognosis; Survival Rate
PubMed: 31791356
DOI: 10.1186/s12957-019-1754-x -
Nutrition & Metabolism Dec 2021Intermittent fasting has been reported to have positive effects on obesity, diabetes, cardiovascular diseases, hypertension, and several neurodegenerative diseases... (Review)
Review
BACKGROUND
Intermittent fasting has been reported to have positive effects on obesity, diabetes, cardiovascular diseases, hypertension, and several neurodegenerative diseases through different mechanisms such as alteration in the gut microbiota. This systematic review was conducted with the aim of providing an overview of the existing animal and human literature regarding the gut microbiota alterations in various fasting regimens.
METHOD
A systematic literature search was conducted on PubMed, Scopus and Web of Science databases up to May 2021 to find all relevant studies examining the gut microbiota alteration during the fasting. Original researches on animal models or human patients were included in this study.
RESULTS
The search fulfilled 3072 documents from which 31 studies (20 animal and 11 human studies) were included. Upon fasting, abundance of several beneficial bacteria including Lactobacillus and Bifidobacterium shifted significantly. Moreover, some taxa, including Odoribacter which negatively associated with blood pressure bloomed during fasting. Ramadan fasting, as a kind of intermittent fasting, improves health parameters through positive changes in gut microbiota including upregulation of A. muciniphila, B. fragilis, Bacteroides and butyric acid-producing Lachnospiraceae.
CONCLUSION
The findings suggest that different fasting regimens including alternate-day fasting, calorie- and time-restricted fasting programs and Ramadan fasting could promote health maybe through the modulation of gut microbiome. However, further studies are needed to explore properly the connection between gut microbiota and meal frequency and timing.
PubMed: 34906176
DOI: 10.1186/s12986-021-00635-3 -
Gut Microbes Nov 2020The effects of dairy and dairy-derived products on the human gut microbiota remains understudied. A systematic literature search was conducted using Medline, CINAHL,...
The effects of dairy and dairy-derived products on the human gut microbiota remains understudied. A systematic literature search was conducted using Medline, CINAHL, Embase, Scopus, and PubMed databases with the aim of collating evidence on the intakes of all types of dairy and their effects on the gut microbiota in adults. Risk of bias was assessed using the Cochrane risk-of-bias tool.The search resulted in 6,592 studies, of which eight randomized controlled trials (RCTs) met pre-determined eligibility criteria for inclusion, consisting of a total of 468 participants. Seven studies assessed the effect of type of dairy (milk, yogurt, and kefir) and dairy derivatives (whey and casein) on the gut microbiota, and one study assessed the effect of the quantity of dairy (high dairy vs low dairy). Three studies showed that dairy types consumed (milk, yogurt, and kefir) increased the abundance of beneficial genera and . One study showed that yogurt reduced the abundance of , a pathogenic strain. Whey and casein isolates and the quantity of dairy consumed did not prompt changes to the gut microbiota composition. All but one study reported no changes to bacterial diversity in response to dairy interventions and one study reported reduction in bacterial diversity in response to milk intake.In conclusion, the results of this review suggest that dairy products such as milk, yogurt, and kefir may modulate the gut microbiota composition in favor to the host. However, the broader health implications of these findings remain unclear and warrant further studies.
Topics: Adult; Animals; Caseins; Dairy Products; Female; Gastrointestinal Microbiome; Humans; Male
PubMed: 32835617
DOI: 10.1080/19490976.2020.1799533