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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 -
Neuropsychobiology 2023The associations between psychological stress and gut microbiota composition are not fully understood. This study investigated associations between psychological stress...
INTRODUCTION
The associations between psychological stress and gut microbiota composition are not fully understood. This study investigated associations between psychological stress and gut microbiota composition and examined the potential modifying effects of age, sex, and ethnicity on such associations.
METHODS
A systematic literature search was conducted using PubMed, Web of Science, PsycINFO, and Embase databases for studies published until November 2021 which examined associations between psychological stress and gut microbiota composition.
RESULTS
During the search process, 10,790 studies were identified, and after screening, 13 met the eligibility criteria and were included. The median sample size was 70, and the median age of participants was 28.0 years. Most of the included studies did not report associations between measures of alpha- and beta diversity of the gut microbiota composition and psychological stress. A few studies reported that the Shannon index, Chao 1, Simpson index, and weighted UniFrac were negatively associated with psychological stress. Significant reductions in several taxa at the phyla-, family-, and genus-levels were observed in participants with higher psychological stress. At the phylum level, the abundance of Proteobacteria and Verrucomicrobia were negatively associated with psychological stress. At the family-level, no more than two studies reported associations of the same microbiota with psychological stress. At the genus level, the following results were found in more than two studies; psychological stress was negatively associated with the abundance of Lachnospira, Lachnospiraceae, Phascolarctobacterium, Sutterella, and Veillonella, and positively associated with the abundance of Methanobrevibacter, Rhodococcus, and Roseburia. However, it was not possible to determine the influence of age, sex, or ethnicity due to the limited studies included.
CONCLUSION
Our findings provide evidence that psychological stress is associated with changes in the abundance of the gut microbiota. Larger sample longitudinal studies are needed to determine the causal relationship between psychological stress and the gut microbiota.
PubMed: 37673059
DOI: 10.1159/000533131 -
Archives of Oral Biology Sep 2021This study aimed to investigate that these bacteria counts in the oral cavity were modulated by the recurrent aphthous stomatitis (RAS) status according to age and... (Meta-Analysis)
Meta-Analysis Review
Quantitative changes of Veillonella, Streptococcus, and Neisseria in the oral cavity of patients with recurrent aphthous stomatitis: A systematic review and meta-analysis.
OBJECTIVE
This study aimed to investigate that these bacteria counts in the oral cavity were modulated by the recurrent aphthous stomatitis (RAS) status according to age and ethnicity with a systematic review and meta-analysis.
DESIGN
The relevant case-control studies were searched in the literature database in English, Korean, and Chinese until June 2020 using keywords, and the literature was screened and collated for Review Manager analysis. Sensitivity analysis and quality check of the included literature were conducted.
RESULTS
From the selection process, oral bacteria counts were measured by polymerase chain reaction (PCR) in 8 studies and next-generation sequencing in 4 studies. Healthy control, ulcerative phases of RAS (UC-RAS), non-ulcerative phases of RAS (Non-UC-RAS) groups included 442, 473, and 386 participants in a total of 12 studies. For PCR detection, mean differences (95 % confidence intervals) of Veillonella and Streptococcus counts between the healthy-control and RAS groups were -1.91 (-2.41 ∼ -1.41) and -1.34 (-1.85 ∼ -0.83)(P < 0.0001). The bacteria count results by "Next-generation" sequencing (NGS) and PCR methods were similar. Significantly lower Veillonella and Streptococcus counts were observed in the UC-RAS group than in the non-UC-RAS group (P < 0.0001). Veillonella and Streptococcus count differences between RAS and controls aged ≥30 years were greater than those aged <30 years. At the species level, the prevalence of RAS had a negative relation with Veillonella dispar count.
CONCLUSIONS
Counts of Veillonella and Streptococcus are strongly correlated with the recovery and progression of RAS, especially in middle-aged patients. Adjustment of oral microbiota should be considered in the treatment of RAS.
Topics: Humans; Middle Aged; Neisseria; Stomatitis, Aphthous; Streptococcus; Veillonella
PubMed: 34167010
DOI: 10.1016/j.archoralbio.2021.105198 -
International Journal of Surgery... Jun 2024The study of changes in the microbiome in chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) holds significant potential for developing noninvasive...
BACKGROUND
The study of changes in the microbiome in chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) holds significant potential for developing noninvasive diagnostic tools as well as innovative interventions to alter the progression of diseases. This systematic review and meta-analysis aimed to analyze in detail the taxonomic and functional characteristics of the gut microbiome in patients with CP and PDAC.
METHODS
Two researchers conducted a systematic search across public databases to gather all published research up to June 2023. Diversity and gut microbiota composition are the main outcomes we focus on.
RESULTS
This meta-analysis included 14 studies, involving a total of 1511 individuals in the PDAC (n=285), CP (n=342), and control (n=649) groups. Our results show a significant difference in the composition of gut microbiota between PDAC/CP patients compared to healthy controls (HC), as evidenced by a slight decrease in α-diversity, including Shannon (SMD=-0.33; P=0.002 and SMD=-0.59; P<0.001, respectively) and a statistically significant β-diversity (P<0.05). The pooled results showed that at the phylum level, the proportion of Firmicutes was lower in PDAC and CP patients than in HC patients. At the genus level, more than two studies demonstrated that 4 genera were significantly increased in PDAC patients compared to HC (e.g., Escherichia-Shigella and Veillonella). CP patients had an increase in 4 genera (e.g., Escherichia-Shigella and Klebsiella) and a decrease in 8 genera (e.g., Coprococcus and Bifidobacterium) compared to HC. Functional/metabolomics results from various studies also showed differences between PDAC/CP patients and HC. In addition, this study found no significant differences in gut microbiota between PDAC and CP patients.
CONCLUSIONS
Current evidence suggests changes in gut microbiota is associated with PDAC/CP, commonly reflected by a reduction in beneficial species and an increase in the pathogenic species. Further studies are needed to confirm these findings and explore therapeutic possibilities.
PubMed: 38847785
DOI: 10.1097/JS9.0000000000001724 -
Frontiers in Oral Health 2021In light of recent technological advances in Next-generation sequencing (NGS) and the accumulation of large, publicly available oral microbiome datasets, the need for...
In light of recent technological advances in Next-generation sequencing (NGS) and the accumulation of large, publicly available oral microbiome datasets, the need for meta-analysing data on caries microbiome is becoming feasible and essential. A consensus on the identification of enriched organisms in cariogenic dysbiotic biofilms would be reached. For example, members of the genus have been detected in caries biofilms, and may have an underestimated contribution to the dysbiotic process. Hence, we aimed to determine the abundance of species in dental caries in studies using NGS data. Analysis was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (registered at PROSPERO: CRD42020204150). Studies investigating microbial composition in saliva, dental biofilm, or carious dentin were included. Six databases and grey literature were searched. Two independent reviewers selected the papers and assessed the methodological quality. Searches retrieved 1,323 titles, from which 38 studies were included in a qualitative synthesis, comprising a total of 1,374 caries and 745 caries-free individuals. Most studies analysed 16S rRNA amplicons, and only 5 studies used shotgun metagenomics and metatranscriptomics. A geographical bias was observed. The methodological quality was downrated in 81.5% of the studies due to the lack of criteria for defining cases and standard criteria used for measurement of the condition in a reliable way. Six studies on early childhood caries (ECC) were meta-analysed, confirming a significant enrichment of spp. in caries-associated biofilms (but not saliva) when compared to caries-free controls [mean difference: 2.22 (0.54-3.90); = 0.01]. . is more abundant in individuals suffering with ECC when compared to caries-free controls (very low evidence certainty), and should be considered for further studies to observe their metabolism in dental caries. There is an urgent need for a consensus in methodologies used to allow for more rigorous comparison between NGS studies, particularly including clinical data and details of caries diagnosis, as they are currently scarce. Inconsistent reporting on the NGS data affected the cross-study comparison and the biological connexions of the relative abundances on caries microbiome.
PubMed: 35048071
DOI: 10.3389/froh.2021.770917 -
Cancers May 2023Oesophagogastric cancer is the fifth most common cancer worldwide, with poor survival outcomes. The role of bacteria in the pathogenesis of oesophagogastric cancer... (Review)
Review
OBJECTIVE
Oesophagogastric cancer is the fifth most common cancer worldwide, with poor survival outcomes. The role of bacteria in the pathogenesis of oesophagogastric cancer remains poorly understood.
DESIGN
A systematic search identified studies assessing the oesophagogastric cancer microbiome. The primary outcome was to identify bacterial enrichment specific to oesophagogastric cancer. Secondary outcomes included appraisal of the methodology, diagnostic performance of cancer bacteria and the relationship between oral and tissue microbiome.
RESULTS
A total of 9295 articles were identified, and 87 studies were selected for analysis. Five genera were enriched in gastric cancer: , , , and . No clear trends were observed in oesophageal adenocarcinoma. , and were abundant in oesophageal squamous cell carcinoma. Functional analysis supports the role of immune cells, localised inflammation and cancer-specific pathways mediating carcinogenesis. STORMS reporting assessment identified experimental deficiencies, considering batch effects and sources of contamination prevalent in low-biomass samples.
CONCLUSIONS
Functional analysis of cancer pathways can infer tumorigenesis within the cancer-microbe-immune axis. There is evidence that study design, experimental protocols and analytical techniques could be improved to achieve more accurate and representative results. Whole-genome sequencing is recommended to identify key metabolic and functional capabilities of candidate bacteria biomarkers.
PubMed: 37345006
DOI: 10.3390/cancers15102668 -
International Journal of Gynecological... Sep 2017Worldwide, 1,470,900 women are diagnosed yearly with a gynecological malignancy (21,000 in the UK). Some patients treated with pelvic radiotherapy develop chronic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND AIM
Worldwide, 1,470,900 women are diagnosed yearly with a gynecological malignancy (21,000 in the UK). Some patients treated with pelvic radiotherapy develop chronic changes in their bowel function. This systematic review summarizes current research on the impact of cancer treatment on the gut and vaginal microbiome in women with a gynecological malignancy.
METHODS
The Preferred reporting Items for Systematic Reviews and Meta-analyses guidelines for systematic reviews were used to ensure transparent and complete reporting. Quantitative studies exploring the gut or vaginal microbiome in this patient cohort were included. Animal studies were excluded. There were no language restrictions.
RESULTS
No studies examined the possible effects of surgery or chemotherapy for gynecological cancers on the gut or vaginal microbiome.Three prospective cohort studies were identified using sequencing of changes in the gut microbiome reporting on a total of 23 women treated for gynecological cancer. All studies included patients treated with radiotherapy with a dosage ranging from 43.0 to 54.0 Gy. Two studies assessed gastrointestinal toxicity formally; 8 women (57%) developed grade 2 or 3 diarrhea during radiotherapy. The outcomes suggest a correlation between changes in the intestinal microbiome and receiving radiotherapy and showed a decrease in abundance and diversity of the intestinal bacterial species. Before radiotherapy, those who developed diarrhea had an increased abundance of Bacteroides, Dialister, and Veillonella (P < 0.01), and a decreased abundance of Clostridium XI and XVIII, Faecalibacterium, Oscillibacter, Parabacteroides, Prevotella, and unclassified bacteria (P < 0.05).
CONCLUSION
The limited evidence to date implies that larger studies including both the vaginal and gut microbiome in women treated for a gynecological malignancy are warranted to explore the impact of cancer treatments on the microbiome and its relation to developing long-term gastrointestinal toxicity. This may lead to new avenues to stratify those at risk and explore personalized treatment options and prevention of gastrointestinal consequences of cancer treatments.
Topics: Cohort Studies; Female; Gastrointestinal Microbiome; Genital Neoplasms, Female; Humans; Prospective Studies; Vagina
PubMed: 28590950
DOI: 10.1097/IGC.0000000000000999 -
Journal of Neurogastroenterology and... Apr 2020Studies that investigated esophageal microbiomes are limited when compared to those on intestinal microbiomes. Nevertheless, several studies have investigated the... (Review)
Review
Studies that investigated esophageal microbiomes are limited when compared to those on intestinal microbiomes. Nevertheless, several studies have investigated the relationship between esophageal microbiomes and various esophageal diseases, owing to the advancement of next-generation sequencing techniques. is the most common bacterial taxon in a normal esophagus. Additionally, , , , and are also found. However, gram-negative bacteria, including , are more abundant in a diseased esophagus, such as in gastroesophageal reflux disease and Barrett's esophagus. This systematic review aims to summarize current evidences on esophageal microbiomes in various esophageal diseases.
PubMed: 32235026
DOI: 10.5056/jnm19240 -
Cureus Feb 2023Heart failure (HF) contributes to the cardiovascular health burden worldwide. Patients with heart failure have been recently studied to possess unique changes in the gut... (Review)
Review
Heart failure (HF) contributes to the cardiovascular health burden worldwide. Patients with heart failure have been recently studied to possess unique changes in the gut microbiome that affect immune homeostasis and metabolism. In this systematic review of the literature, we aim to identify the impact of gut dysbiosis on heart failure. We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines to conduct our systematic review. We searched the literature on databases such as PubMed, PubMed Central (PMC), Medline, and ScienceDirect. Ten articles were included for review. There were significant differences in the gut microbiome composition in heart failure. Relative abundance of and relative depletion of , and The composition varied according to age, heart failure stage, and decompensation level. The composition remained unaltered with ejection fraction. There was an increased expression of genes responsible for the metabolism of amino acids, carbohydrates, choline trimethylamine-lyase (TMA-lyase), lipopolysaccharide (LPS) biosynthesis, tryptophan, and lipid metabolism. The resultant changes affected the levels of metabolites, such as trimethylamine N-oxide (TMAO), indoxyl sulfate (IS), and LPS, and inflammatory markers in the feces and plasma, which contributed to heart failure. These biomarkers of heart failure could serve as targets for the prevention and treatment of heart failure. Patients with heart failure harbor a unique constellation of gut microbiota that affect the pathogenesis of heart failure. Further studies are needed to understand the causal relationship between dysbiosis and heart failure.
PubMed: 36938237
DOI: 10.7759/cureus.34902 -
Environmental Microbiology Reports Apr 2020In recent years, there has been an increase in studies on the implications of gut microbiota (GM) on the behaviour of children with autism spectrum disorders (ASD) due... (Review)
Review
In recent years, there has been an increase in studies on the implications of gut microbiota (GM) on the behaviour of children with autism spectrum disorders (ASD) due to a dysbiosis in GM that can trigger onset, development or progression of ASD through the microbiota-gut-brain axis. The aim of this study is to carry out a systematic review of articles from the last 6 years that analyse GM in children with ASD compared to GM in control groups. Children with ASD showed a higher abundance of Roseburia and Candida genera, and lower abundance of Dialister, Bilophila, Veillonella, Streptococcus, Coprococcus and Prevotella genera. Those differences can be attributed to factors such as different nationalities, nature of control groups, place where the sample was taken, gastrointestinal (GI) problems or bacterial detection methods. It is still too early to define a specific GM profile of children with ASD, and future studies should focus on homogenizing the characteristics of samples and control groups. Furthermore, new multicentre studies should also focus on the impact of GM on GI physiology, neurophysiology and behaviour of children with ASD, and on performing psychometric analyses of the correlation between the severity of ASD behavioural symptoms and GM profiles.
Topics: Autism Spectrum Disorder; Bacteria; Bilophila; Child; Child, Preschool; Clostridiales; Dysbiosis; Female; Gastrointestinal Diseases; Gastrointestinal Microbiome; Humans; Male; Prevotella; Streptococcus; Veillonellaceae
PubMed: 31713352
DOI: 10.1111/1758-2229.12810