Gut microbiome (Cambridge, England)最新文献

There is considerable data suggesting that the gut microbiota (GM) contributes to health and regulates host immunity and influences brain function, findings with implications for neurodegenerative diseases, such as Alzheimer's Disease (AD). In the present study, using three non-fat diets with different ratios of unsaturated ω-6/ω-3 fatty acids (FAs)(high or low), we analyzed how minor differences in diet can affect the microbiota of amyloid precursor protein/Presenilin 1 transgenic (APP/PS1 [TG]) mice, a mice model of AD, next, we studied how the levels of sex hormones may affect the GM. The data obtained show that sex hormones in males fed our standard diet (S) modified alpha and beta diversity, whereas no differences were observed in TG mice compared with wild-type mice. Moreover, there were significant differences in both alpha or beta diversity in mice fed with an H or L diet compared with an S diet. In conclusion, our data indicate that the levels of sex hormones or differences in the ω-6/ω-3 FA ratio alter the GM more than expected. Thus, it is tantalizing to propose that low levels of ω-3 FAs in APP/PS1 mice fed an "H" diet may be responsible for modifying some bacterial genera, exacerbating the basal neuropathology in this AD model.

The Simulator of the Human Intestinal Microbial Ecosystem (SHIME) system was provided with baby feed for one week to stabilise the microbial community, followed by a 10-day period with baby feed and another 10-day period with adult feed. The study was conducted using sterilised and standardised feed formulations, which model dietary conditions in vitro. Following the transition from baby to adult feed, a significant reduction in the proportion of butyrate in comparison to total SCFA was found after transitioning to adult feed in both the transverse colon and distal colon bioreactors. Our findings suggest that abrupt early-life dietary changes from simple to complex carbohydrates as well as the exclusion of bovine milk proteins can transiently lower the ability of the microbiota to produce butyrate. The lack of additional microbial input leads to a delay or impairment of the adaptation to the modified feed composition. However, given the short treatment duration and sterilised feed composition, these findings should be interpreted within the limitations of this in vitro model. A reduction in butyrate concentration following the transition to adult feed may reflect a temporary shift in microbial metabolic activity rather than a long-term impact on energy extraction efficiency in vivo.

The use of antibiotics in fish and shrimp aquaculture all over the world was found to be only partially successful in preventing infectious diseases. However, their overuse has resulted in the contamination of closed aquatic ecosystems, reduced antibiotic resistance in organisms that fight infectious diseases, and compromised the effectiveness of various antibiotic medications in controlling diseases. Excessive use of antibiotics damages aquaculture species and impacts human health, also rendering the most potent antibiotics increasingly ineffective, with limited alternatives. Therefore, intensive research efforts have been made to replace antibiotics with other protocols and methods like vaccines, phage therapy, quorum quenching technology, probiotics, prebiotics, chicken egg yolk antibody (IgY), and plant therapy," etc. Though all these methods have great potential, many of them are still in the experimental stage, except for fish vaccines. All these alternative technologies need to be carefully standardized and evaluated before implementation. In recent times, after realizing the importance of the gut microbiome community in maintaining the health of animals, efforts have been made to use the microbiome strains for the prevention of pathogenic bacterial and viral infections. Now it has been experimentally proven that animals should possess a healthy microbiome community in their gut tract to strengthen the immune system and prevent the entry of harmful pathogens. Investigations are now being carried out on the derivation of various bioactive compounds from the gut microbiome strains and their structural profile and functionality using the molecular tools of metagenomics and bioinformatics. Such newly discovered compounds from microbiomes can be used as potential alternatives to replace antibiotic drugs in the aquaculture industry. These alternatives are likely to emerge as breakthroughs in animal health management and farming, with effects on cost efficiency, species health, productivity, and yield enhancement. Therefore, introducing new micro-innovative technologies into an overall health management plan will be highly beneficial.

Intestinal transit time has been recognized as an important factor in shaping the gut microbiota, although causality remains to be firmly demonstrated. The aim of this study was to evaluate the effect of different loperamide doses on the mouse intestinal transit time and to investigate the effects of increasing transit time on the gut microbial community. Loperamide significantly increased the transit time in a dose-dependent manner. Additionally, we observed a significant difference between the control group and the loperamide-treated groups in the abundance of the bacterial families Bacteroidaceae, Erysipelotrichaceae, Porphyromonadaceae, and Akkermansiaceae after 7 days of loperamide treatment, with the bacterial families responding to the increased transit time at different rates. Fermentation of faeces obtained from the same mice, with or without loperamide, demonstrated that the observed effects on gut microbiota in vivo were not a result of direct interactions between loperamide and the gut microbiota but rather a consequence of loperamide-induced increased intestinal transit time. In the cecum of the mice, we found higher levels of propionate in the high-dose group compared to the control and low-dose groups. Collectively, our findings establish that an altered transit time is causal to changes in the composition and activity of the microbiome.

The human gut microbiome represents an extended "second genome" harbouring about 10¹⁵ microbes containing >100 times the number of genes as the host. States of health and disease are largely mediated by host-microbial metabolic interplay, and the microbiome composition also underlies the differential responses to chemotherapeutic agents between people. Chemical information will be the key to tackle this complexity and discover specific gut microbiome metabolism for creating more personalised interventions. Additionally, rising antibiotic resistance and growing awareness of gut microbiome effects are creating a need for non-microbicidal therapeutic interventions. We classify chemical interventions for the gut microbiome into categories like molecular decoys, bacterial conjugation inhibitors, colonisation resistance-stimulating molecules, "prebiotics" to promote the growth of beneficial microbes, and inhibitors of specific gut microbial enzymes. Moreover, small molecule probes, including click chemistry probes, artificial substrates for assaying gut bacterial enzymes and receptor agonists/antagonists, which engage host receptors interacting with the microbiome, are some other promising developments in the expanding chemical toolkit for probing and modulating the gut microbiome. This review explicitly excludes "biologics" such as probiotics, bacteriophages, and CRISPR to concentrate on chemistry and chemical tools like chemoproteomics in the gut-microbiome context.

Colorectal cancer (CRC) represents a relevant public health problem, with high incidence and mortality in Western countries. CRC can occur as sporadic (65%-75%), common familial (25%), or as a consequence of an inherited predisposition (up to 10%). While unravelling its genetic basis has been a long trip leading to relevant clinical implementation over more than 30 years, other contributing factors remain to be clarified. Among these, micro-organisms have emerged as critical players in the development and progression of the disease, as well as for CRC treatment response. Fusobacterium nucleatum (Fn) has been associated with CRC development in both pre-clinical models and clinical settings. Fusobacteria are core members of the human oral microbiome, while being less prevalent in the healthy gut, prompting questions about their localization in CRC and its precursor lesions. This review aims to critically discuss the evidence connecting Fn with CRC pathogenesis, its molecular subtypes and clinical outcomes.

This study explored the effects of different human milk oligosaccharides (HMOs), solely and in combination, on gut microbiota composition and metabolic activity (organic acid production), using anaerobic in vitro batch culture fermenters. The aim was to compare prebiotic effects of HMOs (2'FL, 3'FL, 3'SL, 6'SL, LNT, LNnT, and 1:1 ratio mixes of 2'FL/3'SL and 3'SL/LNT) in faecal samples from irritable bowel syndrome (IBS) donors and healthy controls, and to determine the best-performing HMO in IBS. Fluorescent in situ hybridisation coupled with flow cytometry was utilised to study microbiota changes in major colonic genera, and organic acid production was assessed by gas chromatography. IBS donors had different starting microbial profiles compared to healthy controls and lower levels of organic acids. In response to HMOs, there were alterations in both the control and IBS faecal microbiomes. In IBS donor fermenters, Bifidobacterium, Faecalibacterium, total bacterial numbers, and organic acid production significantly increased post-HMO intervention. When comparing the effect of HMO interventions on the microbiota and organic acid production, a mix of 3'SL/LNT HMOs may be the most promising intervention for IBS patients.

The endocannabinoidome (eCBome) and the gut microbiota have been implicated in diet-induced obesity and impaired metabolism. While the eCBome and the gut microbiome are known to respond to diet macronutrient composition, interaction with micronutrient intake has been relatively unexplored. Iron (Fe) is an essential micronutrient for the function of enzymes involved in energy and lipid metabolism. Here, we evaluated how 28 days of Fe depletion and enrichment, in interaction with Low Fat-Low Sucrose (LFLS) or High Fat-High Sucrose (HFHS) diets, affect the host via the eCBome, and modulate intestinal gut microbial communities. Circulating levels of N-oleoyl-ethanolamine (OEA) showed an elevation associated with Fe-enriched LFLS diet, while the Fe-depleted HFHS diet showed an elevation of N-arachidonoyl-ethanolamine (anandamide, AEA) and a decrease of circulating linoleic acid. In parallel, the response of intestinal inflammatory mediators to Fe in the diet showed decreased levels of prostaglandins PGE₁, PGE₃, and 1a,1b-dihomo PGF₂α in the caecum. Individual differences in microbial taxa were less pronounced in the ileum than in the caecum, where Eubacterium coprostanoligenes group showed an increase in relative abundance associated with Fe-depleted LFLS diets. In conclusion, our study shows that Fe intake modulates the response to the macronutrient composition of the diet in mice.

Oral supplementation with probiotics, prebiotics, and synbiotics is a novel potential complementary therapy for addressing overweight and obesity through gut microbiota modulation. This systematic review provides a comprehensive summary of the existing evidence to guide future research. Literature searches were conducted in four databases to identify human trials published until May 2024 that examined the impact of probiotic, prebiotic, or synbiotic interventions on faecal microbiota composition changes in overweight and obese participants from Latin American and Caribbean populations (LACPs). Of the 13,090 identified records, five randomised controlled trials (RCTs) from Brazil, Mexico, and Chile met the inclusion criteria for this review. The included RCTs evaluated different forms of therapies over short-term interventions (6 or 8 weeks), with sample sizes ranging from 21 to 39 participants across the studies. Variations in the reported outcomes were observed due to differences in supplement formulation, dosage, population characteristics, and methodological heterogeneity. The findings indicate that the available data are inadequate to establish definitive conclusions regarding the impact of biotic treatments on gut microbiota profiles in LACP. Further research with larger sample sizes and precise microbiota analysis is required to elucidate the implications of dietary interventions on gut microbiota in obesity and related disorders.

The coronavirus disease 2019 (COVID-19) pandemic has caused health issues worldwide. Studies have suggested that modulation of the gut microbiota could attenuate the severity of COVID-19 symptoms. In light of this, we explored the effects of the prebiotic dietary fibre partially hydrolyzed guar gum (PHGG) on SARS-CoV-2 infection in a Syrian hamster model, hypothesizing that modulation of the gut microbiome and intestinal metabolites through PHGG administration would improve COVID-19 disease outcomes. Eight hamsters each were assigned to the PHGG administration and control groups. The PHGG group was given a diet supplemented with 5% PHGG for two weeks. Consequently, PHGG improved the host survival rate to 100% compared to 25% of the control group (P = 0.003) and attenuated morbid weight loss. Another non-infected set of hamsters was used for the analysis of the gut microbiome composition with 16S rRNA amplicon sequencing, serum, and faecal metabolites with GC-MS and LC-MS. PHGG altered the gut microbiome composition and increased the relative abundances of Ileibacterium, Bifidobacterium, and Prevotella. Furthermore, it elevated the concentrations of faecal valeric acid, propionic acid, ursodeoxycholic acid, and serum deoxycholic acid. Taken together, our data suggest that the prebiotic PHGG modulates gut metabolites and has the potential to reduce COVID-19 morbidity.