Influence Gut Microbiota Composition Research Articles

Advances in Research on the Impact of Diet on Human Gut Microbiota Composition and Metabolites

As research into gut microbiota deepens, the impact of diet on the composition of human gut microbiota and their metabolites has gradually become a focal point. This paper reviews recent advancements in understanding how diet influences gut microbiota composition and their metabolic products. Firstly, it introduces the basic concepts of gut microbiota and their role in maintaining health. Next, it explores the effects of different types of diets (such as high-fiber, high-fat, high-protein, and refined sugar diets) on the composition of gut microbiota and analyzes their impact on microbiota diversity. Then, it discusses the influence of diet on gut microbiota metabolites, including short-chain fatty acids, amino acid metabolites, and gases. Further, it examines the practical applications of dietary interventions on health, especially their potential impact on chronic diseases. Finally, the paper summarizes the limitations of current research and suggests future research directions and challenges. Overall, the influence of diet on gut microbiota and their metabolites holds profound health significance and provides important evidence for formulating scientific dietary recommendations.

Gut microbiota modulatory capacity of fermented ketchup in a validated in vitro model of the colon

This study aimed to evaluate the effects of fermented beetroot ketchup enriched with Lactobacillus johnsonii K4 and non-fermented beetroot ketchup on pooled fecal microbiota from healthy adults in in vitro colon model. The research focused on how these products influenced the composition and functionality of the gut microbiota, as well as metabolite production, using the validated dynamic in vitro colon model, TNO Intestinal Model (TIM-2). After an initial starvation phase, a single 60 g dose of predigested and freeze-dried ketchup was introduced into the model. The potential probiotic strain Lactobacillus johnsonii K4 was added over three days. A carbohydrate mixture of standard ileal effluent medium (SIEM) served as the control. Our analysis identified 21 bacterial taxa that were significantly modulated (q-value < 0.2) when comparing ketchup samples to control samples. Notably, the ketchup samples led to an increase in butyrate-producing taxa, including Faecalibacterium, Blautia, Ruminococcaceae, Ruminiclostridium 6, and Anaerostipes. Conversely, there was a reduction in potentially pathogenic genera Desulfovibrio and Escherichia-Shigella. Distinct profiles of short-chain fatty acids (SCFA) were observed among the fermented ketchup, non-fermented ketchup, and control samples. Non-fermented ketchup resulted in higher proportions of acetate, propionate, and butyrate compared to the other interventions. This may be related to the fermentation with lactic acid bacteria in fermented samples with lower levels of substrate for SCFAs production. However, fermented ketchup sample has higher relative abundance of beneficial bacteria like Lactobacillus, Weissella and Dorea in gut microbiota. These findings suggest that beetroot ketchup, can positively influence gut microbiota composition and function, highlighting its potential benefits for human health.

Hirsutella sinensis polysaccharides and Parabacteroides goldsteinii reduce lupus severity in imiquimod-treated mice

BackgroundThe incidence of autoimmune diseases is increasing in developed countries, possibly due to the modern Western diet and lifestyle. We showed earlier that polysaccharides derived from the medicinal fungus Hirsutella sinensis produced anti-inflammatory, anti-diabetic and anti-obesity effects by modulating the gut microbiota and increasing the abundance of the commensal Parabacteroides goldsteinii in mice fed with a high-fat diet. MethodsWe examined the effects of the prebiotics, H. sinensis polysaccharides, and probiotic, P. goldsteinii, in a mouse model of imiquimod-induced systemic lupus erythematosus. ResultsThe fungal polysaccharides and P. goldsteinii reduced markers of lupus severity, including the increase of spleen weight, proteinuria, and serum levels of anti-DNA auto-antibodies and signal transducer and activator of transcription 4 (STAT4). Moreover, the polysaccharides and P. goldsteinii improved markers of kidney and liver functions such as creatinine, blood urea nitrogen, glomerulus damage and fibrosis, and serum liver enzymes. However, the prebiotics and probiotics did not influence gut microbiota composition, colonic histology, or expression of tight junction proteins in colon tissues. ConclusionsOur results indicate that H. sinensis polysaccharides and the probiotic P. goldsteinii can reduce lupus markers in imiquimod-treated mice. These prebiotics and probiotics may therefore be added to other interventions conducive of a healthy lifestyle in order to counter autoimmune diseases.

Characterization of gut microbiota in patients with stage 3-4 chronic kidney disease: a retrospective cohort study.

Multiple factors, such as dietary patterns, pharmaceutical interventions, and exposure to harmful substances, possess the capacity to influence gut microbiota composition. Gut microbiota dysbiosis has emerged as a significant contributor to the progression of chronic kidney disease (CKD) and its associated complications. By comprehending the intricacies of the intestinal microbiota, this research endeavor holds the potential to offer novel perspectives on potential strategies for mitigating CKD progression. In this retrospective analysis, we assessed gut microbiota composition in CKD patients. Fecal samples were collected from a cohort of 44 patients with stage 3-4 CKD, alongside a control group consisting of 132 healthy volunteers. Subsequently, 16s rDNA sequencing was conducted to examine the composition of the gut microbiota. Our findings revealed significant alterations in the diversity of intestinal microbiota in fecal samples between patients with stage 3-4 CKD and healthy subjects. Among the 475 bacterial genera, 164 were shared, while 242 dominant genera were exclusive to healthy subjects and 69 to CKD stages 3-4 samples. Notably, healthy volunteers exhibited a prevalence of intestinal Firmicutes and Bacteroidetes, whereas stage 3-4 CKD patients displayed higher abundance of Proteobacteria and Actinobacteria. The presence of uncultured Coprobacillus sp. notably contributed to distinguishing between the two groups. ROC curve analysis identified distinct microbiota with superior diagnostic efficacy for discriminating stage 3-4 CKD patients from healthy individuals. Metabolic pathway analysis revealed differing dominant pathways between the two groups-the NADH dehydrogenase pathway in healthy individuals and the phosphate acetyltransferase pathway in stage 3-4 CKD patients. Moreover, the CKD cohort displayed a higher proportion of Gram-negative bacteria and facultative anaerobes. In conclusion, our study underscores the profound influence of gut microbiota dysbiosis on CKD progression. The distinct microbial profiles observed in CKD patients highlight the potential efficacy of microbiota-based interventions in mitigating CKD advancement.

Curdlan-polyphenol complexes prepared by pH-driven effectively enhanced their physicochemical stability, antioxidant and prebiotic activities

In this study, the curdlan-polyphenol complexes were constructed by a pH-driven method. The interaction between curdlan and various hydrophobic polyphenols (curcumin, quercetin, and chlorogenic acid) was investigated. Curdlan could self-assemble into particles for loading polyphenols through hydrogen bonding and hydrophobic interactions. The three polyphenols were embedded in curdlan in an amorphous state. The curdlan-curcumin complex showed the lowest viscoelasticity but exhibited the highest curcumin loading ability (34.04 ± 1.73 mg/g). However, the curdlan-chlorogenic acid complex emerged the opposite trend, indicating that the loading capacity was associated with the hydrophobicity of polyphenols. The antioxidant activity of curdlan significantly increased after combining with polyphenols, which could be maintained during in vitro simulated gastrointestinal digestion. In particular, the curdlan-quercetin complex exhibited the highest antioxidant activity and short-chain fatty acid concentration, which could influence gut microbiota composition by promoting the proliferation of Prevotella and inhibiting the growth of Escherichia_Shigella. In conclusion, the curdlan-polyphenol complexes prepared by an alcohol-free pH-driven method could effectively enhance the gastrointestinal stability of polyphenols as well as increase the antioxidant and prebiotic activities of curdlan, which could be applied as a functional ingredient to improve gut health.

The Interaction Between Nutraceuticals and Gut Microbiota: a Novel Therapeutic Approach to Prevent and Treatment Parkinson's Disease.

Parkinson's disease (PD) is a complex neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons, leading to motor and non-motor symptoms. Emerging research has shed light on the role of gut microbiota in the pathogenesis and progression of PD. Nutraceuticals such as curcumin, berberine, phytoestrogens, polyphenols (e.g., resveratrol, EGCG, and fisetin), dietary fibers have been shown to influence gut microbiota composition and function, restoring microbial balance and enhancing the gut-brain axis. The mechanisms underlying these benefits involve microbial metabolite production, restoration of gut barrier integrity, and modulation of neuroinflammatory pathways. Additionally, probiotics and prebiotics have shown potential in promoting gut health, influencing the gut microbiome, and alleviating PD symptoms. They can enhance the gut's antioxidant capacity of the gut, reduce inflammation, and maintain immune homeostasis, contributing to a neuroprotective environment. This paper provides an overview of the current state of knowledge regarding the potential of nutraceuticals and gut microbiota modulation in the prevention and management of Parkinson's disease, emphasizing the need for further research and clinical trials to validate their effectiveness and safety. The findings suggest that a multifaceted approach involving nutraceuticals and gut microbiota may open new avenues for addressing the challenges of PD and improving the quality of life for affected individuals.

The Gut Microbiota in Parkinson Disease: Interactions with Drugs and Potential for Therapeutic Applications.

The concept of a 'microbiota-gut-brain axis' has recently emerged as an important player in the pathophysiology of Parkinson disease (PD), not least because of the reciprocal interaction between gut bacteria and medications. The gut microbiota can influence levodopa kinetics, and conversely, drugs administered for PD can influence gut microbiota composition. Through a two-step enzymatic pathway, gut microbes can decarboxylate levodopa to dopamine in the small intestine and then dehydroxylate it to m-tyramine, thus reducing availability. Inhibition of bacterial decarboxylation pathways could therefore represent a strategy to increase levodopa absorption. Other bacterial perturbations common in PD, such as small intestinal bacterial overgrowth and Helicobacter pylori infection, can also modulate levodopa metabolism, and eradication therapies may improve levodopa absorption. Interventions targeting the gut microbiota offer a novel opportunity to manage disabling motor complications and dopa-unresponsive symptoms. Mediterranean diet-induced changes in gut microbiota composition might improve a range of non-motor symptoms. Prebiotics can increase levels of short-chain fatty acid-producing bacteria and decrease pro-inflammatory species, with positive effects on clinical symptoms and levodopa kinetics. Different formulations of probiotics showed beneficial outcomes on constipation, with some of them improving dopamine levels; however, the most effective dosage and duration and long-term effects of these treatments remain unknown. Data from faecal microbiota transplantation studies are preliminary, but show encouraging trends towards improvement in both motor and non-motor outcomes.This article summarises the most up-to-date knowledge in pharmacomicrobiomics in PD, and discusses how the manipulation of gut microbiota represents a potential new therapeutic avenue for PD.

When smoke meets gut: deciphering the interactions between tobacco smoking and gut microbiota in disease development.

Tobacco smoking is a prevalent and detrimental habit practiced worldwide, increasing the risk of various diseases, including chronic obstructive pulmonary disease (COPD), cardiovascular disease, liver disease, and cancer. Although previous research has explored the detrimental health effects of tobacco smoking, recent studies suggest that gut microbiota dysbiosis may play a critical role in these outcomes. Numerous tobacco smoke components, such as nicotine, are found in the gastrointestinal tract and interact with gut microbiota, leading to lasting impacts on host health and diseases. This review delves into the ways tobacco smoking and its various constituents influence gut microbiota composition and functionality. We also summarize recent advancements in understanding how tobacco smoking-induced gut microbiota dysbiosis affects host health. Furthermore, this review introduces a novel perspective on how changes in gut microbiota following smoking cessation may contribute to withdrawal syndrome and the degree of health improvements in smokers.

Beyond Diet and Exercise: The Impact of Gut Microbiota on Control of Obesity.

Obesity, a widespread health concern characterized by the excessive accumulation of body fat, is a complex condition influenced by genetics, environment, and social determinants. Recent research has increasingly focused on the role of gut microbiota in obesity, highlighting its pivotal involvement in various metabolic processes. The gut microbiota, a diverse community of microorganisms residing in the gastrointestinal tract, interacts with the host in a myriad of ways, impacting energy metabolism, appetite regulation, inflammation, and the gut-brain axis. Dietary choices significantly shape the gut microbiota, with diets high in fat and carbohydrates promoting the growth of harmful bacteria while reducing beneficial microbes. Lifestyle factors, like physical activity and smoking, also influence gut microbiota composition. Antibiotics and medications can disrupt microbial diversity, potentially contributing to obesity. Early-life experiences, including maternal obesity during pregnancy, play a vital role in the developmental origins of obesity. Therapeutic interventions targeting the gut microbiota, including prebiotics, probiotics, fecal microbiota transplantation, bacterial consortium therapy, and precision nutrition, offer promising avenues for reshaping the gut microbiota and positively influencing weight regulation and metabolic health. Clinical applications of microbiota-based therapies are on the horizon, with potential implications for personalized treatments and condition-based interventions. Emerging technologies, such as next-generation sequencing and advanced bioinformatics, empower researchers to identify specific target species for microbiota-based therapeutics, opening new possibilities in healthcare. Despite the promising outlook, microbiota-based therapies face challenges related to microbial selection, safety, and regulatory issues. However, with ongoing research and advances in the field, these challenges can be addressed to unlock the full potential of microbiota-based interventions.

Exploring the human gut microbiota targets in relation to the use of contemporary antidepressants

BackgroundAntidepressants, specifically selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), are commonly prescribed for depression treatment. Animal studies have shown that antidepressants can influence gut microbiota composition and specific bacterial taxa. We aimed to investigate the association between antidepressant use and human gut microbiota composition and functional pathway. MethodsWe collected information on antidepressant use, demographic, food patterns, and clinical characteristics through questionnaires and medical records. The gut microbiota profiles of 271 depressive patients were carried out through 16S rRNA gene sequencing. Patients were categorized based on different types of antidepressant use groups for gut microbiota comparisons. MaAsLin2 was performed to evaluate microbiota composition across groups. PICRUSt2 was used to predict microbiota functional pathways. ResultsPatients taking SSRIs or SNRIs had a lower microbiota diversity. We found seven taxa abundances (Turicibacter, Barnesiella, Lachnospiraceae_ND3007_group, Romboutia, Akkermansia, Dialister, Romboutia and Fusicatenibacter) differed in patients with various types of antidepressants compared with those without antidepressant treatments (p < 0.05). Turicibacter inversely correlated with depression severity in SSRIs or SNRI users (r = −0.43, p < 0.05). Top identified pathways were related to compound fermentation and biosynthesis in microbiota function. ConclusionAntidepressant usage, especially SSRIs and SNRIs, associates with changes in gut microbiota composition and specific taxa. Given our study's preliminary cross-sectional nature, further research is warranted to comprehend the relationship between antidepressant use, treatment response, and gut microbiota, aiming to enhance therapeutic interventions in the future.

Alkylresorcinols as New Modulators of the Metabolic Activity of the Gut Microbiota.

Alkylresorcinols (ARs) are polyphenolic compounds with a wide spectrum of biological activities and are potentially involved in the regulation of host metabolism. The present study aims to establish whether ARs can be produced by the human gut microbiota and to evaluate alterations in content in stool samples as well as metabolic activity of the gut microbiota of C57BL, db/db, and LDLR (-/-) mice according to diet specifications and olivetol (5-n-pentylresorcinol) supplementation to estimate the regulatory potential of ARs. Gas chromatography with mass spectrometric detection was used to quantitatively analyse AR levels in mouse stool samples; faecal microbiota transplantation (FMT) from human donors to germ-free mice was performed to determine whether the intestinal microbiota could produce AR molecules; metagenome sequencing analysis of the mouse gut microbiota followed by reconstruction of its metabolic activity was performed to investigate olivetol's regulatory potential. A significant increase in the amounts of individual members of AR homologues in stool samples was revealed 14 days after FMT. Supplementation of 5-n-Pentylresorcinol to a regular diet influences the amounts of several ARs in the stool of C57BL/6 and LDLR (-/-) but not db/db mice, and caused a significant change in the predicted metabolic activity of the intestinal microbiota of C57BL/6 and LDLR (-/-) but not db/db mice. For the first time, we have shown that several ARs can be produced by the intestinal microbiota. Taking into account the dependence of AR levels in the gut on olivetol supplementation and microbiota metabolic activity, AR can be assumed to be potential quorum-sensing molecules, which also influence gut microbiota composition and host metabolism.

Low and high doses of oral maslinic acid protect against Parkinson’s disease via distinct gut microbiota-related mechanisms

The use of oral agents that can modify the gut microbiota (GM) could be a novel preventative or therapeutic option for Parkinson’s disease (PD). Maslinic acid (MA), a pentacyclic triterpene acid with GM-dependent biological activities when it is taken orally, has not yet been reported to be effective against PD. The present study found both low and high dose MA treatment significantly prevented dopaminergic neuronal loss in a classical chronic PD mouse model by ameliorating motor functions and improving tyrosine hydroxylase expressions in the substantia nigra pars compacta (SNpc) and increasing dopamine and its metabolite homovanillic acid levels in the striatum. However, the effects of MA in PD mice were not dose-responsive, since similar beneficial effects for low and high doses of MA were observed. Further mechanism studies indicated that low dose MA administration favored probiotic bacterial growth in PD mice, which helped to increase striatal serotonin, 5-hydroxyindole acetic acid, and γ-aminobutyric acid levels. High dose MA treatment did not influence GM composition in PD mice but significantly inhibited neuroinflammation as indicated by reduced levels of tumor necrosis factor alpha and interleukin 1β in the SNpc; moreover, these effects were mainly mediated by microbially-derived acetic acid in the colon. In conclusion, oral MA at different doses protected against PD via distinct mechanisms related to GM. Nevertheless, our study lacked in-depth investigations of the underlying mechanisms involved; future studies will be designed to further delineate the signaling pathways involved in the interactive actions between different doses of MA and GM.

Maternal transmission gives way to social transmission during gut microbiota assembly in wild mice

BackgroundThe mammalian gut microbiota influences a wide array of phenotypes which are relevant to fitness, yet knowledge about the transmission routes by which gut microbes colonise hosts in natural populations remains limited. Here, we use an intensively studied wild population of wood mice (Apodemus sylvaticus) to examine how vertical (maternal) and horizontal (social) transmission routes influence gut microbiota composition throughout life.ResultsWe identify independent signals of maternal transmission (sharing of taxa between a mother and her offspring) and social transmission (sharing of taxa predicted by the social network), whose relative magnitudes shift as hosts age. In early life, gut microbiota composition is predicted by both maternal and social relationships, but by adulthood the impact of maternal transmission becomes undetectable, leaving only a signal of social transmission. By exploring which taxa drive the maternal transmission signal, we identify a candidate maternally-transmitted bacterial family in wood mice, the Muribaculaceae.ConclusionOverall, our findings point to an ontogenetically shifting transmission landscape in wild mice, with a mother’s influence on microbiota composition waning as offspring age, while the relative impact of social contacts grows.

Fine-scale spatial variation shape fecal microbiome diversity and composition in black-tailed prairie dogs (Cynomys ludovicianus)

BackgroundHost associated gut microbiota are important in understanding the coevolution of host-microbe, and how they may help wildlife populations to adapt to rapid environmental changes. Mammalian gut microbiota composition and diversity may be affected by a variety of factors including geographic variation, seasonal variation in diet, habitat disturbance, environmental conditions, age, and sex. However, there have been few studies that examined how ecological and environmental factors influence gut microbiota composition in animals' natural environments. In this study, we explore how host habitat, geographical location and environmental factors affect the fecal microbiota of Cynomys ludovicianus at a small spatial scale. We collected fecal samples from five geographically distinct locations in the Texas Panhandle classified as urban and rural areas and analyzed them using high throughput 16S rRNA gene amplicon sequencing.ResultsThe results showed that microbiota of these fecal samples was largely dominated by the phylum Bacteroidetes. Fecal microbiome diversity and composition differed significantly across sampling sites and habitats. Prairie dogs inhabiting urban areas showed reduced fecal diversity due to more homogenous environment and, likely, anthropogenic disturbance. Urban prairie dog colonies displayed greater phylogenetic variation among replicates than those in rural habitats. Differentially abundant analysis revealed that bacterial species pathogenic to humans and animals were highly abundant in urban areas which indicates that host health and fitness might be negatively affected. Random forest models identified Alistipes shahii as the important species driving the changes in fecal microbiome composition. Despite the effects of habitat and geographic location of host, we found a strong correlation with environmental factors and that- average maximum temperature was the best predictor of prairie dog fecal microbial diversity.ConclusionsOur findings suggest that reduction in alpha diversity in conjunction with greater dispersion in beta diversity could be indicative of declining host health in urban areas; this information may, in turn, help determine future conservation efforts. Moreover, several bacterial species pathogenic to humans and other animals were enriched in prairie dog colonies near urban areas, which may in turn adversely affect host phenotype and fitness.

Cytomegalovirus infection disrupts the influence of short-chain fatty acid producers on Treg/Th17 balance

BackgroundBoth the gut microbiota and chronic viral infections have profound effects on host immunity, but interactions between these influences have been only superficially explored. Cytomegalovirus (CMV), for example, infects approximately 80% of people globally and drives significant changes in immune cells. Similarly, certain gut-resident bacteria affect T-cell development in mice and nonhuman primates. It is unknown if changes imposed by CMV on the intestinal microbiome contribute to immunologic effects of the infection.ResultsWe show that rhesus cytomegalovirus (RhCMV) infection is associated with specific differences in gut microbiota composition, including decreased abundance of Firmicutes, and that the extent of microbial change was associated with immunologic changes including the proliferation, differentiation, and cytokine production of CD8+ T cells. Furthermore, RhCMV infection disrupted the relationship between short-chain fatty acid producers and Treg/Th17 balance observed in seronegative animals, showing that some immunologic effects of CMV are due to disruption of previously existing host-microbe relationships.ConclusionsGut microbes have an important influence on health and disease. Diet is known to shape the microbiota, but the influence of concomitant chronic viral infections is unclear. We found that CMV influences gut microbiota composition to an extent that is correlated with immunologic changes in the host. Additionally, pre-existing correlations between immunophenotypes and gut microbes can be subverted by CMV infection. Immunologic effects of CMV infection on the host may therefore be mediated by two different mechanisms involving gut microbiota.CSBmPNqVbm-wbH_WVfXSdnVideo

The Therapeutic Role of Short-Chain Fatty Acids Mediated Very Low-Calorie Ketogenic Diet-Gut Microbiota Relationships in Paediatric Inflammatory Bowel Diseases.

The very low-calorie ketogenic diet (VLCKD) has been recognized as a promising dietary regimen for the treatment of several diseases. Short-chain fatty acids (SCFAs) produced by anaerobic bacterial fermentation of indigestible dietary fibre in the gut have potential value for their underlying epigenetic role in the treatment of obesity and asthma-related inflammation through mediating the relationships between VLCKD and the infant gut microbiota. However, it is still unclear how VLCKD might influence gut microbiota composition in children, and how SCFAs could play a role in the treatment of inflammatory bowel disease (IBD). To overcome this knowledge gap, this review aims to investigate the role of SCFAs as key epigenetic metabolites that mediate VLCKD–gut microbiota relationships in children, and their therapeutic potential in IBD.

Gnotobiotic mice housing conditions critically influence the phenotype associated with transfer of faecal microbiota in a context of obesity

ObjectiveFaecal microbiota transplantation (FMT) in germ-free (GF) mice is a common approach to study the causal role of the gut microbiota in metabolic diseases. Lack of consideration of housing conditions...

Peanuts as a nighttime snack enrich butyrate-producing bacteria compared to an isocaloric lower-fat higher-carbohydrate snack in adults with elevated fasting glucose: A randomized crossover trial

Tree nuts have glucoregulatory effects and influence gut microbiota composition. The effect of peanuts on the microbiota has not been investigated. The aim was to examine the effect of 28g/d of peanuts for 6-wks, compared to an isocaloric lower-fat higher-carbohydrate (LFHC) snack, on gut microbiota composition. A secondary aim was toidentify functional and active compositional differences in a subset of participants using metatranscriptomics. In a randomized, crossover trial, 50 adults (48% female; 42±15y; BMI 28.3±5.6kg/m2; plasma glucose 100±8mg/dL) consumed 28g/d of dry roasted, unsalted, peanuts (164kcal; 11% E carbohydrate, 17% E protein, 73% E fat, and 2.4g fiber) or a LFHC snack (164kcal; 53% E carbohydrate, 17% E protein, 33% E fat, and 3g fiber) for 6-wk (4-wk washout period). Gut bacterial composition was measured using 16S rRNA sequencing in the whole cohort. Exploratory metatranscriptomic analyses were conducted on a random subset (n=24) of samples from the Peanut condition. No between-condition differences in α- or β- diversity were observed. Following peanut intake, Ruminococcaceae were significantly more abundant [Linear discriminant analysis score (LDA)=2.8; P=0.027)] compared to LFHC. Metatranscriptomics showed increased expression of the K03518 (aerobic carbon-monoxide dehydrogenase small subunit) gene following peanut intake (LDA=2.0; P=0.004) and Roseburia intestinalis L1-82 was identified as a contributor to the increased expression. An increased abundance of Ruminococcaceae was observed following consumption of 28g/d of peanuts in adults with elevated fasting glucose after 6-wks. Metatranscriptomics revealed increased expression of the K03518 gene. These results suggest peanut intake enriches a known butyrate producer and the increased expression of a gene implicated in butyrate production adds further support for peanut-induced gut microbiome modulation. NCT: 03654651.

Animal unit hygienic conditions influence mouse intestinal microbiota and contribute to T-cell-mediated colitis.

Inflammatory bowel disease (IBD) is a group of chronic inflammatory disorders of the gastrointestinal tract with worldwide increasing incidence. Recent studies indicate that certain species of intestinal bacteria are strongly associated with IBD. Helper T lymphocytes are not only the key players in mediating host defense against a wide variety of pathogens but also contribute to pathogenesis of many immune-related diseases. Here, using the T cell transfer model of colitis, we observed that the mice maintained in a specific-pathogen free (SPF) unit after receiving naïve CD4+ T cells developed mild disease. The same mice developed different degrees of disease when they were maintained in a conventional animal facility (non-SPF), where some pathogens were detected during routine health monitoring. Consistently, increased circulating inflammatory cytokines as well as Th1 and Th17 cells were detected in mice housed in non-SPF units. 16S rRNA sequencing of feces samples enabled us to identify changes in the microbiota composition of mice kept in different facilities. Our data indicate that environmental factors influence gut microbiota composition of mice, leading to development of colitis in a T-cell-dependent manner. In conclusion, changes in environmental conditions and microbial status of experimental animals appear to contribute to progression of colitis.

Dietary Fats and the Gut Microbiota: Their impacts on lipid-induced metabolic syndrome

The metabolic syndrome (MetS) produces low-grade inflammation, endothelial dysfunction, platelet hyperactivity, oxidative stress and ultimately contributes to cardiovascular disease (CVD) development. Fatty acids such as n-3 and n-6, monounsaturated, conjugated, highly unsaturated, short-chain types, and their metabolism can impact the development of MetS and associated features. Furthermore, the quality and quantity of dietary fats can influence gut microbiota composition that alters an individual's metabolic health. The gut microbiota modulates components of MetS via different mechanisms. The gut microbiota can swing the host metabolic balance in energy homeostasis, gut motility, appetite, lipid and carbohydrate metabolism, and fat storage in the liver. In addition, an impairment of the gut microbial population by a high-fat diet can lead to systemic inflammation and insulin resistance. The review summarizes the impacts of dietary fats on MetS and their interactions with gut microbiota in modulating the risk factors associated with metabolic syndrome. .