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Spinal Cord Apr 2022Systematic review. (Review)
Review
STUDY DESIGN
Systematic review.
OBJECTIVES
To investigate the changes in the microbiome among human and animal populations with spinal cord injury (SCI).
METHODS
Four databases (EMBASE, Medline (Ovid), Web of Science, Cochrane Central Register of Trials (CENTRAL)) and Google Scholar were searched. No language restrictions were applied. Data extraction was done in parallel and independently by two reviewers. The search was last conducted on 07 April 2021.
RESULTS
There were 6869 studies retrieved, 43 full-text studies reviewed, and 19 studies included. There were seven animal gut studies, six human gut studies, and six urinary tract studies identified. There were no publications found on other body sites. Among the included studies, we observed a consistent and significant difference in gut microbiome composition between populations with SCI and able-bodied populations. This is characterized by a decrease in beneficial butyrate-producing bacteria (Faecalbacterium, Megamonas, Roseburia) and an increase in inflammation-associated bacteria (Alistipes, Anaerotruncus, and Lachnoclostridium). On the other hand, the urine of individuals with SCI was polymicrobial and members of Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae) were frequently observed. Probiotics were shown to induce a significant but transient shift in the urinary tract microbiome. The studies had low to moderate risks of bias.
CONCLUSIONS
There are limited studies on the changes in microbiome among SCI populations. The gut microbiome was characterized by bacterial profiles associated with chronic inflammation and metabolic disorder while the studies of the urinary tract microbiome show the dominance of bacterial genera associated with urinary tract infection.
Topics: Animals; Bacteria; Gastrointestinal Microbiome; Humans; Inflammation; Metabolic Diseases; Probiotics; Spinal Cord Injuries
PubMed: 34992210
DOI: 10.1038/s41393-021-00737-y -
Foods (Basel, Switzerland) Feb 2021Obesity is a disease growing at an alarming rate and numerous preclinical studies have proven the role of polyphenols in managing this disease. This systematic review... (Review)
Review
Obesity is a disease growing at an alarming rate and numerous preclinical studies have proven the role of polyphenols in managing this disease. This systematic review explores the prebiotic effect of polyphenols in the management of obesity among animals fed on a high-fat diet. A literature search was carried out in PubMed, Scopus, CINAHL, Web of Science, and Embase databases following the PRISMA guidelines. Forty-four studies reported a significant reduction in obesity-related parameters. Most notably, 83% of the studies showed a decrease in either body weight/visceral adiposity/plasma triacylglyceride. Furthermore, 42 studies reported a significant improvement in gut microbiota (GM), significantly affecting the genera , , , , , , , and . Polyphenols' anti-obesity, anti-hyperglycaemic, and anti-inflammatory properties were associated with their ability to modulate GM. This review supports the notion of polyphenols as effective prebiotics in ameliorating HFD-induced metabolic derangements in animal models.
PubMed: 33540692
DOI: 10.3390/foods10020299 -
Frontiers in Psychiatry 2019Recently discovered relationships between the gastrointestinal microbiome and the brain have implications for psychiatric disorders, including major depressive disorder...
Recently discovered relationships between the gastrointestinal microbiome and the brain have implications for psychiatric disorders, including major depressive disorder (MDD). Bacterial transplantation from MDD patients to rodents produces depression-like behaviors. In humans, case-control studies have examined the gut microbiome in healthy and affected individuals. We systematically reviewed existing studies comparing gut microbial composition in MDD and healthy volunteers. A PubMed literature search combined the terms "depression," "depressive disorder," "stool," "fecal," "gut," and "microbiome" to identify human case-control studies that investigated relationships between MDD and microbiota quantified from stool. We evaluated the resulting studies, focusing on bacterial taxa that were different between MDD and healthy controls. Six eligible studies were found in which 50 taxa exhibited differences ( < 0.05) between patients with MDD and controls. Patient characteristics and methodologies varied widely between studies. Five phyla-, and -were represented; however, divergent results occurred across studies for all phyla. The largest number of differentiating taxa were within phylum , in which nine families and 12 genera differentiated the diagnostic groups. The majority of these families and genera were found to be statistically different between the two groups in two identified studies. Family differentiated the diagnostic groups in four studies (with an even split in directionality). Across all five phyla, nine genera were higher in MDD (, and ), six were lower (, and ), and six were divergent (, and ). We highlight mechanisms and products of bacterial metabolism as they may relate to the etiology of depression. No consensus has emerged from existing human studies of depression and gut microbiome concerning which bacterial taxa are most relevant to depression. This may in part be due to differences in study design. Given that bacterial functions are conserved across taxonomic groups, we propose that studying microbial functioning may be more productive than a purely taxonomic approach to understanding the gut microbiome in depression.
PubMed: 30804820
DOI: 10.3389/fpsyt.2019.00034 -
Revista Espanola de Enfermedades... Nov 2015The human colonic mucosa is populated by a wide range of microorganisms, usually in a symbiotic relation with the host. Sometimes this balance is lost and a state of... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND AIM
The human colonic mucosa is populated by a wide range of microorganisms, usually in a symbiotic relation with the host. Sometimes this balance is lost and a state of dysbiosis arises, exposing the colon to different metabolic and inflammatory stimuli (according to the microbiota's changing profile). Recent findings lead to hypothesize that this unbalance may create a subclinical pro-inflammatory state that increases DNA mutations and, therefore, colorectal carcinogenesis. In this article we aim to systematically review the scientific evidence regarding colonic microbiota and its role in colorectal carcinogenesis.
METHODS
Systematic review of PubMed searching results for original articles studying microbiota and colorectal cancer until November 2014.
RESULTS
Thirty-one original articles studied the role of colon microbiota in colorectal carcinoma including both human and animal studies. Different and heterogeneous methods were used and different bacteria were considered. Nevertheless, some bacteria are consistently augmented (such as Fusobacteria, Alistipes, Porphyromonadaceae, Coriobacteridae, Staphylococcaceae, Akkermansia spp. and Methanobacteriales), while other are constantly diminished in colorectal cancer (such as Bifidobacterium, Lactobacillus, Ruminococcus, Faecalibacterium spp., Roseburia, and Treponema). Moreover, bacteria metabolites amino acids are increased and butyrate is decreased throughout colonic carcinogenesis.
CONCLUSION
Conclusive evidence shows that colorectal carcinogenesis is associated with microbial dysbiosis. This information may be used to create new prophylactic, diagnostic and therapeutic strategies for colorectal cancer.
Topics: Animals; Carcinogenesis; Colon; Colorectal Neoplasms; Dysbiosis; Humans; Microbiota
PubMed: 26541655
DOI: 10.17235/reed.2015.3830/2015