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Frontiers in Cellular and Infection... 2022Evidence of gut microbiota involvement in regulating glucose metabolism and type 2 diabetes mellitus (T2DM) progression is accumulating. The understanding of microbial... (Review)
Review
Evidence of gut microbiota involvement in regulating glucose metabolism and type 2 diabetes mellitus (T2DM) progression is accumulating. The understanding of microbial dysbiosis and specific alterations of gut microbiota composition that occur during the early stages of glucose intolerance, unperturbed by anti-diabetic medications, is especially essential. Hence, this systematic review was conducted to summarise the existing evidence related to microbiota composition and diversity in individuals with prediabetes (preDM) and individuals newly diagnosed with T2DM (newDM) in comparison to individuals with normal glucose tolerance (nonDM). A systematic search of the PubMed, MEDLINE and CINAHL databases were conducted from inception to February 2021 supplemented with manual searches of the list of references. The primary keywords of "type 2 diabetes", "prediabetes", "newly-diagnosed" and "gut microbiota" were used. Observational studies that conducted analysis of the gut microbiota of respondents with preDM and newDM were included. The quality of the studies was assessed using the modified Newcastle-Ottawa scale by independent reviewers. A total of 18 studies (5,489 participants) were included. Low gut microbial diversity was generally observed in preDM and newDM when compared to nonDM. Differences in gut microbiota composition between the disease groups and nonDM were inconsistent across the included studies. Four out of the 18 studies found increased abundance of phylum along with decreased abundance of in newDM. At the genus/species levels, decreased abundance of , , , and and increased abundance of , a, and were observed in the disease groups in at least two studies. was also found to positively correlate with fasting plasma glucose (FPG), HbA1c and/or homeostatic assessment of insulin resistance (HOMA-IR) in four studies. This renders a need for further investigations on the species/strain-specific role of endogenously present in glucose regulation mechanism and T2DM disease progression. Differences in dietary intake caused significant variation in specific bacterial abundances. More studies are needed to establish more consistent associations, between clinical biomarkers or dietary intake and specific gut bacterial composition in prediabetes and early T2DM.
Topics: Bacteroidetes; Diabetes Mellitus, Type 2; Gastrointestinal Microbiome; Glucose; Humans; Microbiota; Verrucomicrobia
PubMed: 36046745
DOI: 10.3389/fcimb.2022.943427 -
Frontiers in Psychiatry 2020Cumulative evidence shows a linkage between gut microbiota pattern and depression through the brain-gut microbiome axis. The aim of this systematic review was to...
Cumulative evidence shows a linkage between gut microbiota pattern and depression through the brain-gut microbiome axis. The aim of this systematic review was to identify the alterations of the gut microbiota patterns in people with depression compared to healthy controls. A comprehensive literature search of human studies, published between January 2000 and June 2019, was reviewed. The key words included gastrointestinal microbiome, gut microbiome, microbiota, depression, depressive symptoms, and depressive disorder. The systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Nine articles met the eligibility criteria. Disparities in α-diversity and β-diversity of the microbiota existed in people with depression compared to healthy controls. At the phylum level, there were inconsistencies in the abundance of , , . However, high abundance in and phyla were observed in people with depression. On the family level, high abundance of , , , , , , , , , , , , , low abundance of , , , , , , and were observed in people with depression. On the genus level, high abundance of , , , , , , , , , , , , , , , , , , , , , , , and low abundance of , , , , , , , and were found in people with depression. Alteration of gut microbiome patterns was evident in people with depression. Further evidence is warranted to allow for the translation of microbiome findings toward innovative clinical strategies that may improve treatment outcomes in people with depression.
PubMed: 32587537
DOI: 10.3389/fpsyt.2020.00541 -
Gastroenterology Mar 2020Altering the intestinal microbiota has been proposed as a treatment for inflammatory bowel diseases (IBDs), but there are no established associations between specific...
BACKGROUND & AIMS
Altering the intestinal microbiota has been proposed as a treatment for inflammatory bowel diseases (IBDs), but there are no established associations between specific microbes and IBD. We performed a systematic review to identify frequent associations.
METHODS
We searched the MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials databases, through April 2, 2018 for studies that compared intestinal microbiota (from fecal or colonic or ileal tissue samples) among patients (adult or pediatric) with IBD vs healthy individuals (controls). The primary outcome was difference in specific taxa in fecal or intestinal tissue samples from patients with IBD vs controls. We used the Newcastle-Ottawa scale to assess the quality of studies included in the review.
RESULTS
We identified 2631 citations; 48 studies from 45 articles were included in the analysis. Most studies evaluated adults with Crohn's disease or ulcerative colitis. All 3 studies of Christensenellaceae and Coriobacteriaceae and 6 of 11 studies of Faecalibacterium prausnitzii reported a decreased amount of those organisms compared with controls, whereas 2 studies each of Actinomyces, Veillonella, and Escherichia coli revealed an increased amount in patients with Crohn's disease. For patients with ulcerative colitis, Eubacterium rectale and Akkermansia were decreased in all 3 studies, whereas E coli was increased in 4 of 9 studies. The microbiota diversity was either decreased or not different in patients with IBD vs controls. Fewer than 50% of the studies stated comparable sexes and ages of cases and controls.
CONCLUSIONS
In a systematic review, we found evidence for differences in abundances of some bacteria in patients with IBD vs controls, but we cannot make conclusions due to inconsistent results and methods among studies. Further large-scale studies, with better methods of assessing microbe populations, are needed.
Topics: Colitis, Ulcerative; Crohn Disease; Feces; Gastrointestinal Microbiome; Humans; Inflammatory Bowel Diseases; Intestines
PubMed: 31812509
DOI: 10.1053/j.gastro.2019.11.294 -
Head & Neck Aug 2023The relationship between head and neck squamous cell carcinoma (HNSCC) and the oral microbiome has been drawn in various studies. Microbial diversities, microbiome... (Review)
Review
OBJECTIVES
The relationship between head and neck squamous cell carcinoma (HNSCC) and the oral microbiome has been drawn in various studies. Microbial diversities, microbiome profiles, metagenomic analysis, and host-pathogen interactions were collected from these studies to highlight similarities and account for inconsistencies. We also evaluate the possible clinical applications of the microbiome regarding screening and diagnosis of HNSCC.
METHODS
Systematic analysis of studies regarding HNSCC and the microbiome was done according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Articles were retrieved from four databases (PubMed, ScienceDirect, CUHK Full-Text Journals, and Cochrane database) and were screened using predefined criteria.
RESULTS
Twenty studies were chosen after screening for full-text review. α-diversity comparison was inconsistent whereas β-diversity between HNSCC and normal samples showed distinct clustering. Microbial dysbiosis characterized by change in the relative abundances of several bacterial species were also seen in HNSCC patients. At a phylum level, inconsistencies were seen between studies using HNSCC tumor tissue samples and saliva samples. At a genus level, Fusobacterium, Peptostreptococcus, Alloprevotella, Capnocytophaga, Catonella, and Prevotella were differentially enriched in HNSCC while Streptococcus, Actinomyces Veillonella, and Rothia were differentially depleted. Co-occurrence network analysis revealed a positive correlation of HNSCC with periodontal pathogens and a negative correlation with commensal bacteria. Metagenomic analysis of microbiota revealed a differential enrichment of pro-inflammatory genomic pathways which was consistent across various studies. Microbial dysbiosis was applied in clinical use as a tool for HNSCC screening. Random-forest analysis was adopted to differentiate between tumor and normal tissue, at 95.7% and 70.0% accuracies respectively in two studies. Microbial dysbiosis index was also used to predict prognosis.
CONCLUSIONS
Oral microbial dysbiosis could be a promising tool for HNSCC screening and diagnosis. However, more research should be conducted pertaining to clinical applications to improve diagnostic accuracy and explore other clinical uses.
Topics: Humans; Bacteria; Dysbiosis; Head and Neck Neoplasms; Microbiota; Squamous Cell Carcinoma of Head and Neck
PubMed: 37249085
DOI: 10.1002/hed.27422 -
Frontiers in Cellular and Infection... 2024The incidence of biliary system diseases has been continuously increasing in the past decade. Biliary system diseases bring a heavy burden to humanity and society....
INTRODUCTION
The incidence of biliary system diseases has been continuously increasing in the past decade. Biliary system diseases bring a heavy burden to humanity and society. However, the specific etiology and pathogenesis are still unknown. The biliary system, as a bridge between the liver and intestine, plays an indispensable role in maintaining the physiological metabolism of the body. Therefore, prevention and treatment of biliary diseases are crucial. It is worth noting that the microorganisms participate in the lipid metabolism of the bile duct, especially the largest proportion of intestinal bacteria.
METHODS
We systematically reviewed the intestinal microbiota in patients with gallstones (GS), non-calculous biliary inflammatory, and biliary tract cancer (BTC). And searched Pubmed, Embase and Web of science for research studies published up to November 2023.
RESULTS
We found that the abundance of Faecalibacterium genus is decreased in GS, primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and BTC. Veillonella, Lactobacillus, Streptococcus and Enterococcus genus were significantly increased in PSC, PBC and BTC. Interestingly, we found that the relative abundance of Clostridium was generally reduced in GS, PBC and BTC. However, Clostridium was generally increased in PSC.
DISCUSSION
The existing research mostly focuses on exploring the mechanisms of bacteria targeting a single disease. Lacking comparison of multiple diseases and changes in bacteria during the disease process. We hope to provide biomarkers forearly diagnosis of biliary system diseases and provide new directions for the mechanism of intestinal microbiota in biliary diseases.
Topics: Humans; Gastrointestinal Microbiome; Cholangitis, Sclerosing; Biliary Tract; Liver; Biomarkers; Bacteria
PubMed: 38558851
DOI: 10.3389/fcimb.2024.1362933 -
Microorganisms Apr 2023Evidence from the literature suggests an association between the microbiome and asthma development. Here, we aimed to identify the current evidence for the association... (Review)
Review
Evidence from the literature suggests an association between the microbiome and asthma development. Here, we aimed to identify the current evidence for the association between asthma and the upper airway, lower airway and/or the gut microbiome. An electronic systemic search of PubMed, EBSCO, Science Direct and Web of Science was conducted until February 2022 to identify the eligible studies. The Newcastle-Ottawa Scale and the Systematic Review Centre for Laboratory Animal Experimentation risk of the bias tools were used to assess quality of included studies. Twenty-five studies met the inclusion criteria. Proteobacteria and Firmicutes were identified as being significantly higher in the asthmatic children compared with the healthy controls. The high relative abundance of , and in the microbiome of the upper airway in early infancy was associated with a higher risk of asthma development later in life. The gut microbiome analyses indicated that a high relative abundance of in early childhood might be associated with asthma development later in life. The findings reported here serve as potential microbiome signatures associated with the increased risk of asthma development. There is a need for large longitudinal studies to further identify high-risk infants, which will help in design strategies and prevention mechanisms to avoid asthma early in life.
PubMed: 37110362
DOI: 10.3390/microorganisms11040939 -
Seminars in Cancer Biology Nov 2022The higher incidence of bladder cancer in men has long been attributed to environmental factors, including smoking. The fact that the sex ratio of bladder cancer remains... (Review)
Review
The higher incidence of bladder cancer in men has long been attributed to environmental factors, including smoking. The fact that the sex ratio of bladder cancer remains consistently weighted toward men despite the remarkable increase in the prevalence of smoking among women suggests that other risk factors influence the incidence rates of bladder cancer. These factors may include the urinary microbiota. In this study, we provide a review of recent literature regarding the association between bladder cancer and changes in the urinary microbiota, with a focus on the potential role of uropathogens in the microbiota and sex in bladder cancer. Four databases were systematically searched up to 31 March 2021 to identify human case-controlled studies that evaluated the relationship between urinary microbiota and bladder cancer. We combined bacterial taxa that were significantly higher or lower in the bladder cancer group in each study in the urine (voided and catheterized) and tissue samples. Findings from sixteen eligible studies were analyzed. The total sample size of the included studies was 708 participants, including 449 (63.4 %) bladder cancer patients and 259 (36.6 %) participants in the control group. When considering only the taxa that have been reported in at least two different studies, we observed that with regards to neoplastic tissues, no increased taxa were reported, while Lactobacillus (2/5 of the studies on tissue samples) was increased in nonneoplastic-tissue compared to neoplastic-tissues at the genus level. In catheterized urine, Veillonella (2/3 of the studies on catheterized urine) was increased in bladder cancer patients compared to the control groups at the genus level. In voided urine, Acinetobacter, Actinomyces, Aeromonas, Anaerococcus, Pseudomonas, and Tepidomonas were increased in the bladder cancer patients, while Lactobacillus, Roseomonas, Veillonella were increased in the control groups. Regarding gender, the genus Actinotignum was increased in female participants while Streptococcus was increased in male participants at the genus level. Regarding potential uropathogens in the urinary microbiota, Escherichia-Shigella provided conflicting results, with both showing higher and lower levels in the bladder cancer groups. However, the family Enterobacteriaceae was lower in the bladder cancer groups than in the control groups. In conclusion, there is no consensus on what taxa of the urinary microbiota are associated with bladder cancer according to the sample type. Findings on the potential role of uropathogens in the urinary microbiota in bladder cancer remain inconsistent. Due to the limited number of studies, further studies on urinary microbiota and bladder cancer are needed to address this issue. Given that all publications concerning the urinary microbiota and bladder cancer have been performed using 16S rRNA gene sequencing, we propose that polyphasic approaches, including culture-dependent techniques, may allow for a more comprehensive investigation of the urinary microbiota associated with bladder cancer.
Topics: Humans; Female; Male; Urinary Bladder Neoplasms; RNA, Ribosomal, 16S; Urinary Bladder; Microbiota; Bacteria
PubMed: 34979272
DOI: 10.1016/j.semcancer.2021.12.010 -
Antibiotics (Basel, Switzerland) Nov 2023(1) Introduction: Current evidence shows that mechanical debridement augmented with systemic and topical antibiotics may be beneficial for the treatment of... (Review)
Review
(1) Introduction: Current evidence shows that mechanical debridement augmented with systemic and topical antibiotics may be beneficial for the treatment of peri-implantitis. The microbial profile of peri-implantitis plays a key role in identifying the most suitable antibiotics to be used for the treatment and prevention of peri-implantitis. This systematic review aimed to summarize and critically analyze the methodology and findings of studies which have utilized sequencing techniques to elucidate the microbial profiles of peri-implantitis. (2) Results: sp. are associated with peri-implantitis. sp. are associated with healthy implant sites and exhibit a reduced prevalence in deeper pockets and with greater severity of disease progression. sp. have been identified both in diseased and healthy sites. sp. have been associated with healthy implants and negatively correlate with the probing depth. Methanogens and AAGPRs were also detected in peri-implantitis sites. (3) Methods: The study was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023459266). The PRISMA criteria were used to select articles retrieved from a systematic search of the Scopus, Cochrane, and Medline databases until 1 August 2023. Title and abstract screening was followed by a full-text review of the included articles. Thirty-two articles were included in the final qualitative analysis. (4) Conclusions: A distinct microbial profile could not be identified from studies employing sequencing techniques to identify the microbiome. Further studies are needed with more standardization to allow a comparison of findings. A universal clinical parameter for the diagnosis of peri-implantitis should be implemented in all future studies to minimize confounding factors. The subject pool should also be more diverse and larger to compensate for individual differences, and perhaps a distinct microbial profile can be seen with a larger sample size.
PubMed: 37998812
DOI: 10.3390/antibiotics12111610 -
Clinical and Experimental Dental... Dec 2022Diet is one of the main factors influencing the diversity and interactions of the oral microbiota. The purpose of this study is to determine the impact of sugar intake... (Review)
Review
OBJECTIVES
Diet is one of the main factors influencing the diversity and interactions of the oral microbiota. The purpose of this study is to determine the impact of sugar intake on the microbial diversity and bacteria that predominate under these conditions.
MATERIAL AND METHODS
A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guide, using the PubMed, Scopus, and Science Direct databases and combinations of the words "microbiota," "microbiology," "bacteria," "sugars," "dysbiosis," "caries," "microbiome," "oral microbial," and "oral microbiota profile pattern." The selection criteria included year, language, type of publication, comparison of microbiota during low and high sugar intake, and bacterial identification by molecular sequencing of the 16S subunit of ribosomal RNA.
RESULTS
Out of a total of 374 papers that came up after the initial search, 8 met the criteria for this review. The papers included research on populations comprising children, young adults, and adults, with most of the studies reporting selection criteria for the participants and using validated instruments to determine sugar intake. Apart from one study, all others reported for high sugar intake conditions a significant decrease in microbial diversity of the oral microbiome and the predominance of several bacterial genera or species, including Streptococcus, Scardovia, Veillonella, Rothia, Actinomyces, and Lactobacillus.
CONCLUSIONS
Sugar-rich diets have a significantly unfavorable effect on the diversity and balance of oral microbiota; however, further studies are required to determine the exact role of sugar in microbial interactions.
Topics: Child; Young Adult; Humans; Microbiota; Bacteria; Dental Caries; Dysbiosis; Sugars
PubMed: 35946056
DOI: 10.1002/cre2.640 -
Microbiome Research Reports 2023There is growing evidence that physical activity modulates gut microbiota composition through complex interactions between diet and microbial species. On the other... (Review)
Review
There is growing evidence that physical activity modulates gut microbiota composition through complex interactions between diet and microbial species. On the other hand, next-generation sequencing techniques include shotgun metagenomics and 16S amplicon sequencing. These methodologies allow a comprehensive characterisation of microbial communities of athletes from different disciplines as well as non-professional players and sedentary adults exposed to training. This systematic review summarises recent applications of next-generation sequencing to characterise the athletic gut microbiome. A systematic review of microbiome research was performed to determine the association of microbiota composition profiles with sports performance. Bibliographic analysis revealed the importance of a novel research trend aiming at deciphering the associations between individual microbial species and sports performance. In addition, literature review highlighted the role of butyrate-producing bacteria such as , , , and unidentified species belonging to , and species in gut health and sports performance across several disciplines. Interestingly, metabolic activities of and involved in branched amino acid and lactate metabolism may contribute to reducing muscular fatigue. Other microbial metabolic pathways of interest involved in carbohydrate metabolism showed increased proportions in athletes´ metagenomes. Future research will aim at developing personalised nutrition interventions to modulate key species associated with certain components of exercise.
PubMed: 38045609
DOI: 10.20517/mrr.2022.16