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Journal of Clinical Medicine Mar 2023A bidirectional kidney-gut axis was described in patients with chronic kidney disease (CKD). On the one hand, gut dysbiosis could promote CKD progression, but on the... (Review)
Review
BACKGROUND
A bidirectional kidney-gut axis was described in patients with chronic kidney disease (CKD). On the one hand, gut dysbiosis could promote CKD progression, but on the other hand, studies reported specific gut microbiota alterations linked to CKD. Therefore, we aimed to systematically review the literature on gut microbiota composition in CKD patients, including those with advanced CKD stages and end-stage kidney disease (ESKD), possibilities to shift gut microbiota, and its impact on clinical outcomes.
MATERIALS AND METHODS
We performed a literature search in MEDLINE, Embase, Scopus, and Cochrane databases to find eligible studies using pre-specified keywords. Additionally, key inclusion and exclusion criteria were pre-defined to guide the eligibility assessment.
RESULTS
We retrieved 69 eligible studies which met all inclusion criteria and were analyzed in the present systematic review. Microbiota diversity was decreased in CKD patients as compared to healthy individuals. Ruminococcus and Roseburia had good power to discriminate between CKD patients and healthy controls (AUC = 0.771 and AUC = 0.803, respectively). Roseburia abundance was consistently decreased in CKD patients, especially in those with ESKD ( < 0.001). A model based on 25 microbiota dissimilarities had an excellent predictive power for diabetic nephropathy (AUC = 0.972). Several microbiota patterns were observed in deceased ESKD patients as compared to the survivor group (increased Lactobacillus, Yersinia, and decreased Bacteroides and Phascolarctobacterium levels). Additionally, gut dysbiosis was associated with peritonitis and enhanced inflammatory activity. In addition, some studies documented a beneficial effect on gut flora composition attributed to synbiotic and probiotic therapies. Large randomized clinical trials are required to investigate the impact of different microbiota modulation strategies on gut microflora composition and subsequent clinical outcomes.
CONCLUSIONS
Patients with CKD had an altered gut microbiome profile, even at early disease stages. Different abundance at genera and species levels could be used in clinical models to discriminate between healthy individuals and patients with CKD. ESKD patients with an increased mortality risk could be identified through gut microbiota analysis. Modulation therapy studies are warranted.
PubMed: 36902734
DOI: 10.3390/jcm12051948 -
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 -
Avian Pathology : Journal of the W.V.P.A Jul 2024Probiotics can enhance broiler chicken health by improving intestinal microbiota, potentially replacing antibiotics. They protect against bacterial diseases like... (Review)
Review
Probiotics can enhance broiler chicken health by improving intestinal microbiota, potentially replacing antibiotics. They protect against bacterial diseases like necrotic enteritis (NE) in poultry. Understanding their role is crucial for managing bacterial diseases, including NE. This study conducted a meta-analysis to assess the effects of probiotic supplementation on feed conversion ratio (FCR), NE lesion score, and mortality. Additionally, a systematic review analysed gut microbiota changes in broilers challenged with with or without the probiotic supplementation. Effect sizes from the studies were estimated in terms of standardized mean difference (SMD). Random effect models were fitted to estimate the pooled effect size and 95% confidence interval (CI) of the pooled effect size between the control [probiotic-free + ] and the treatment [ supplemented + ] groups. Overall variance was computed by heterogeneity (Q). The meta-analysis showed that probiotic supplementation significantly improved FCR and reduced NE lesion score but had no effect on mortality rates. The estimated overall effects of probiotic supplementation on FCR, NE lesion score and mortality percentage in terms of SMD were -0.91 (CI = -1.34, -0.49; < 0.001*); -0.67 (CI = -1.11, -0.22; = 0.006*), and -0.32 (CI = -0.70, 0.06; = 0.08), respectively. Heterogeneity analysis indicated significant variations across studies for FCR (Q = 69.66; < 0.001*) and NE lesion score (Q = 42.35; < 0.001*) while heterogeneity was not significant for mortality (Q = 2.72; = 0.74). probiotic supplementation enriched specific gut microbiota including . These microbiotas were found to upregulate expression of various genes such as TJ proteins occluding, ZO-1, junctional adhesion 2 (JAM2), interferon gamma, IL12-β and transforming growth factor-β4. Moreover, downregulated mucin-2 expression was involved in restoring the intestinal physical barrier, reducing intestinal inflammation, and recovering the physiological functions of damaged intestines. These findings highlight the potential benefits of probiotic supplementation in poultry management, particularly in combating bacterial diseases and promoting intestinal health.
PubMed: 38776185
DOI: 10.1080/03079457.2024.2359596 -
Kidney & Blood Pressure Research 2022China has the largest absolute burden of hypertension (HTN) in the world. Gut dysbiosis may be a potentially modifiable risk factor for HTN. However, the characteristics... (Meta-Analysis)
Meta-Analysis
BACKGROUND
China has the largest absolute burden of hypertension (HTN) in the world. Gut dysbiosis may be a potentially modifiable risk factor for HTN. However, the characteristics of gut microbiota in Chinese populations with HTN remain to be determined.
METHODS
We systematically searched for studies comparing the gut microbial in HTN with healthy controls in databases. The cut-off date was December 30, 2021. Semiquantitative analysis and meta-analysis with standardized mean differences of the alteration in gut microbiota were carried out.
RESULTS
A total of 16 studies involving 2,372 patients with HTN and 849 controls were included, covering 16 Chinese provinces or regions. The present study supports that compared to healthy population, the diversity of patients with HTN is significantly compromised, while richness is overall preserved. To be specific, a significant increase of the Firmicutes (F)/Bacteroidetes (B) ratio is considered as a special parameter of gut microbiota in HTN patients. The increased abundance of phylum Firmicutes, genus Megasphaera, Escherichia_Shigella, and Klebsiella while the lower abundance of phylum Bacteroidetes, genus Bifidobacterium, Faecalibacterium, Roseburia, and Ruminococcus may be associated with HTN. The gut microbial metabolism in HTN was more abundant in lipopolysaccharide biosynthesis, membrane transport, and steroid degradation.
CONCLUSIONS
Variation in gut microbial parameters is likely associated with Chinese patients with HTN. Further investigations should distinguish geographical and ethnic characteristics to develop in-depth knowledge of the underlying mechanisms by which gut dysbiosis contributes to HTN.
Topics: Asian People; China; Dysbiosis; Gastrointestinal Microbiome; Humans; Hypertension
PubMed: 35398848
DOI: 10.1159/000524282 -
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 -
Nutrients Jan 2021Dietary iron and zinc deficiencies are a global health concern. Bacteria that colonize the gastrointestinal tract depend on minerals to maintain their activities; thus,... (Meta-Analysis)
Meta-Analysis
Dietary iron and zinc deficiencies are a global health concern. Bacteria that colonize the gastrointestinal tract depend on minerals to maintain their activities; thus, recent evidence suggests that biofortified foods can modulate the host's beneficial bacterial taxa. The current review analyzed the research data that linked between iron and zinc biofortified foods and gut microbiota modulation. The data analysis was based on the PRISMA guidelines and the data search was performed at PubMed, Web of Science, Science Direct, and Scopus databases for experimental studies published from January 2010 until December 2020. The five selected studies were conducted in an experimental in vivo model (). The identified and discussed research showed positive effects of biofortified foods on the composition and function of the gut microbiota. Further, an increase in short chain fatty acids producing bacterial populations as and , and a decrease in potentially pathogenic bacteria as , , and was identified due to the consumption of biofortified foods. In conclusion, biofortified foods may contribute to improved gut health without increasing the colonization of pathogenic bacteria. The dietary inclusion of approximately 50% of iron/zinc biofortified foods has a significant beneficial effect on the gut microbiota. Additional studies in humans and animal models are warranted to further establish the suggested effects on the intestinal microbiome. PROSPERO (CRD42020184221).
Topics: Animals; Bacteria; Biodiversity; Chickens; Diet; Fatty Acids, Volatile; Food, Fortified; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Iron; Iron, Dietary; Zinc
PubMed: 33435398
DOI: 10.3390/nu13010189 -
Diagnostic Microbiology and Infectious... Jul 2024Increasing evidence has indicated dysbiosis of the gut microbiota in patients with pulmonary tuberculosis (PTB). However, the change in the intestinal microbiota varies... (Review)
Review
Increasing evidence has indicated dysbiosis of the gut microbiota in patients with pulmonary tuberculosis (PTB). However, the change in the intestinal microbiota varies between different studies. This systematic review was conducted to investigate the characteristics of the gut microbiota in PTB patients. The MBASE, MEDLINE, Web of Science, and Cochrane Library electronic databases were systematically searched, and the quality of the retrieved studies was evaluated using the Newcastle-Ottawa scale. A total of 12 studies were finally included in the systematic review. Compared with healthy controls, the index reflecting α-diversity including the richness and/or diversity index decreased in 6 studies, while β-diversity presented significant differences in PTB patients in 10 studies. Although the specific gut microbiota alterations were inconsistent, short-chain fatty acid-producing bacteria (including Lachnospiraceae, Ruminococcus, Blautia, Dorea, and Faecalibacterium), bacteria associated with an inflammatory state (e.g., Prevotellaceae and Prevotella), and beneficial bacteria (e.g., Bifidobacteriaceae and Bifidobacterium) were commonly noted. Our systematic review identifies key evidence for gut microbiota alterations in PTB patients, in comparison with healthy controls; however, no consistent conclusion could be drawn, due to the inconsistent results and heterogeneous methodologies of the enrolled studies. Therefore, more well-designed research with standard methodologies and large sample sizes is required.
Topics: Humans; Gastrointestinal Microbiome; Tuberculosis, Pulmonary; Dysbiosis; Bacteria
PubMed: 38581928
DOI: 10.1016/j.diagmicrobio.2024.116291 -
PloS One 2024Alterations in the composition and abundance of the intestinal microbiota occur in non-alcoholic fatty liver disease (NAFLD). However, the results are inconsistent... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Alterations in the composition and abundance of the intestinal microbiota occur in non-alcoholic fatty liver disease (NAFLD). However, the results are inconsistent because of differences in the study design, subject area, and sequencing methodology. In this study, we compared the diversity and abundance of the intestinal microbiota of patients with NAFLD and healthy individuals through a systematic review and meta-analysis.
METHODS
Three databases (PubMed, EMBASE, and Cochrane Library) were searched from their inception to March 20, 2023. A meta-analysis was performed using Stata software to analyze variations in the richness and abundance of the intestinal microbiota in patients with NAFLD. The Newcastle-Ottawa Quality Assessment Scale (NOS) was used for quality assessment.
RESULTS
A total of 28 articles were included. Shannon diversity was reduced in patients with NAFLD (SMD = -0.24 (95% CI -0.43-0.05, I2 = 71.7%). The relative abundance of Ruminococcus, Faecalibacterium, and Coprococcus all decreased, with total SMDs of -0.96 (95% CI -1.29 to -0.63, I2 = 4.8%), -1.13 (95% CI -2.07 to -0.19, I2 = 80.5%), and -1.66 (95% CI -3.04 to -0.28, I2 = 91.5%). Escherichia was increased in individuals with NAFLD (SMD = 1.78, 95% CI 0.12 to 3.45, I2 = 94.4%).
CONCLUSION
Increasing the species diversity and altering the abundance of specific gut microbiota, including Coprococcus, Faecalibacterium, Ruminococcus, and Escherichia, may be beneficial for improving NAFLD.
Topics: Humans; Non-alcoholic Fatty Liver Disease; Gastrointestinal Microbiome; Gram-Positive Cocci; Faecalibacterium; Research Design; Clostridiales
PubMed: 38547205
DOI: 10.1371/journal.pone.0299946 -
Expert Review of Anti-infective Therapy Feb 2023This systematic review evaluates the gut microbiota (GM) status in tuberculosis (TB) patients compared to healthy volunteers due to the disease or its treatment.
INTRODUCTION
This systematic review evaluates the gut microbiota (GM) status in tuberculosis (TB) patients compared to healthy volunteers due to the disease or its treatment.
AREAS COVERED
We conducted a systematic review of all articles published in PubMed, Web of Science, and Embase that assessed the impact of TB disease and anti-tubercular therapy (ATT) on GM from inception till January 2022 (Protocol registration number in PROSPERO: CRD42021261884). Regarding the microbial diversity indices and taxonomy, we found a significant difference in GM status between the TB and healthy control (HC) groups. We found an overabundance of Phylum and depletion of some short-chain fatty acid-producing bacteria genera like , and in the TB group. We found that ATT exacerbates the degree of dysbiosis caused by disease.
EXPERT OPINION
The modulation of GM in TB patients in clinical practice may serve as a promising target to reverse the dysbiosis caused. Moreover, this can optimistically change the TB treatment outcome. We expect that appropriate probiotic supplementation with antimycobacterial treatment during tuberculosis disease will help stabilize the GM throughout the treatment phase and protect the GM from dysbiosis.
Topics: Humans; Gastrointestinal Microbiome; Dysbiosis; Tuberculosis; Mycobacterium tuberculosis; Treatment Outcome
PubMed: 36564016
DOI: 10.1080/14787210.2023.2162879 -
BMC Genomics Aug 2022The histidine metabolism and transport (his) genes are controlled by a variety of RNA-dependent regulatory systems among diverse taxonomic groups of bacteria including...
BACKGROUND
The histidine metabolism and transport (his) genes are controlled by a variety of RNA-dependent regulatory systems among diverse taxonomic groups of bacteria including T-box riboswitches in Firmicutes and Actinobacteria and RNA attenuators in Proteobacteria. Using a comparative genomic approach, we previously identified a novel DNA-binding transcription factor (named HisR) that controls the histidine metabolism genes in diverse Gram-positive bacteria from the Firmicutes phylum.
RESULTS
Here we report the identification of HisR-binding sites within the regulatory regions of the histidine metabolism and transport genes in 395 genomes representing the Bacilli, Clostridia, Negativicutes, and Tissierellia classes of Firmicutes, as well as in 97 other HisR-encoding genomes from the Actinobacteria, Proteobacteria, and Synergistetes phyla. HisR belongs to the TrpR family of transcription factors, and their predicted DNA binding motifs have a similar 20-bp palindromic structure but distinct lineage-specific consensus sequences. The predicted HisR-binding motif was validated in vitro using DNA binding assays with purified protein from the human gut bacterium Ruminococcus gnavus. To fill a knowledge gap in the regulation of histidine metabolism genes in Firmicutes genomes that lack a hisR repressor gene, we systematically searched their upstream regions for potential RNA regulatory elements. As result, we identified 158 T-box riboswitches preceding the histidine biosynthesis and/or transport genes in 129 Firmicutes genomes. Finally, novel candidate RNA attenuators were identified upstream of the histidine biosynthesis operons in six species from the Bacillus cereus group, as well as in five Eubacteriales and six Erysipelotrichales species.
CONCLUSIONS
The obtained distribution of the HisR transcription factor and two RNA-mediated regulatory mechanisms for histidine metabolism genes across over 600 species of Firmicutes is discussed from functional and evolutionary points of view.
Topics: Actinobacteria; Bacteria; DNA; Gene Expression Regulation, Bacterial; Gram-Positive Bacteria; Histidine; Humans; Phylogeny; Riboswitch; Transcription Factors
PubMed: 36008760
DOI: 10.1186/s12864-022-08796-y