Effect of Resistant Starch on the Gut Microbiota and Its Metabolites in Patients with Coronary Artery Disease.
ABSTRACT: AIM:Bacteroides vulgatus and B. dorei have a protective effect against atherosclerosis, suggesting that expansion of these species in the gut microbiota could help patients with coronary artery disease (CAD). This study aimed to investigate the effect of resistant starch (RS) on the gut microbiota and its metabolites in fecal sample cultures from patients with CAD and individuals without CAD, using a single-batch fermentation system. METHODS:Fecal samples from 11 patients with CAD and 10 individuals without CAD were fermented for 30 h with or without RS in the Kobe University Human Intestinal Microbiota Model (KUHIMM). Gut microbiota and the abundance of B. vulgatus and B. dorei were analyzed using 16S ribosomal ribonucleic acid (rRNA) gene sequencing and the quantitative polymerase chain reaction. Short-chain fatty acids were analyzed using high-performance liquid chromatography. RESULTS:Gut microbial analysis showed significantly lower levels of B. vulgatus and B. dorei in the original fecal samples from patients with CAD, which was simulated after 30 h of fermentation in the KUHIMM. Although RS significantly increased the absolute numbers of B. vulgatus and B. dorei, and butyrate levels in CAD fecal sample cultures, the numbers varied among each patient. CONCLUSIONS:The effect of RS on gut microbiota and its metabolites in the KUHIMM varied between CAD and non-CAD fecal sample cultures. The KUHIMM may be useful for preclinical evaluations of the effects of RS on the gut microbiota and its metabolites.
Project description:Polycystic ovary syndrome (PCOS) is characterized by androgen excess, ovulatory dysfunction and polycystic ovaries1, and is often accompanied by insulin resistance2. The mechanism of ovulatory dysfunction and insulin resistance in PCOS remains elusive, thus limiting the development of therapeutics. Improved metabolic health is associated with a relatively high microbiota gene content and increased microbial diversity3,4. This study aimed to investigate the impact of the gut microbiota and its metabolites on the regulation of PCOS-associated ovarian dysfunction and insulin resistance. Here, we report that Bacteroides vulgatus was markedly elevated in the gut microbiota of individuals with PCOS, accompanied by reduced glycodeoxycholic acid and tauroursodeoxycholic acid levels. Transplantation of fecal microbiota from women with PCOS or B. vulgatus-colonized recipient mice resulted in increased disruption of ovarian functions, insulin resistance, altered bile acid metabolism, reduced interleukin-22 secretion and infertility. Mechanistically, glycodeoxycholic acid induced intestinal group 3 innate lymphoid cell IL-22 secretion through GATA binding protein 3, and IL-22 in turn improved the PCOS phenotype. This finding is consistent with the reduced levels of IL-22 in individuals with PCOS. This study suggests that modifying the gut microbiota, altering bile acid metabolism and/or increasing IL-22 levels may be of value for the treatment of PCOS.
Project description:Background: Epidemiological studies confirmed that moderate alcohol consumption was associated with a reduced risk of adverse cardiovascular events. It is increasingly recognized that the composition of gut microbiota and metabolites is involved in modulating the cardiovascular health of the host. However, the association of moderate alcohol consumption with serum metabolites and gut microbiome and its impact on coronary artery disease (CAD) is not fully investigated. Method: Serum untargeted metabolomics analysis and fecal 16S rRNA sequencing were performed on 72 male patients with CAD having various alcohol consumption (36 non-drinkers, 18 moderate drinkers, and 18 heavy drinkers) and 17 matched healthy controls. MetaboAnalyst and PICRUSt2 were utilized to analyze the possible involved metabolic pathways. Multi-omics analysis was achieved by Spearman correlation to reveal the interactions of alcohol consumption with gut microbiome and serum metabolites in patients with CAD. Results: We noted distinct differences between patients with CAD, with varying levels of alcohol consumption and healthy controls in aspects of serum metabolome and the gut microbiome. Moderate alcohol consumption significantly changed the lipidomic profiles, including reductions of sphingolipids and glycerophospholipids in moderate drinkers with CAD when compared with non and heavy drinkers with CAD. Moreover, we also found the reduction of microbial-derived metabolites in moderate drinkers with CAD, such as 2-phenylacetamide and mevalonic acid. To be noted, the gut microbiota of moderate drinkers with CAD tended to resemble that of healthy controls. Compared with non-drinkers, the relative abundance of genus Paraprevotella, Lysinibacillus was significantly elevated in moderate drinkers with CAD, while the genus Bifidobacterium, Megasphaera, and Streptococcus were significantly reduced in moderate drinkers with CAD. Multi-omics analysis revealed that specific metabolites and microbes associated with moderate alcohol consumption were correlated with the severity of CAD. Conclusions: Our study revealed that the impact of moderate alcohol consumption on serum metabolites and gut microbiota in patients with CAD seemed to be separated from that of heavy and non-alcohol consumption. Moderate drinking tended to have more positive effects on metabolic profiles and commensal flora, which may explain its beneficial effects on cardiovascular health. Overall, our study provides a novel insight into the effects of moderate alcohol consumption in patients with CAD.
Project description:Dietary carbohydrates are anaerobically fermented by gut microbiota to short-chain fatty acids (SCFAs), conferring gut health benefits. Of all tested prebiotics, galactooligosaccharides (GOS) and resistant starch (RS) stimulated the SCFA production in mud crab (Scylla paramamosain), a crustacean model, to a greater extent than the other carbohydrates tested. Using in vitro anaerobic fermentation cultures, this study further explored the prebiotic potential of GOS and RS in mud crab by assessing their impacts on gut microbiota changes and SCFA production. Both GOS and RS significantly promoted SCFA production. Bacterial diversity in the GOS group was lower than in the RS or control group. GOS promoted the growth of Bacteroidetes, while RS promoted Tenericutes. A strong positive correlation was found between SCFA production and bacterial abundance; most bacteria per se correlated with each other. The findings demonstrated the prebiotic potential of GOS and RS in mud crab.
Project description:The gastrointestinal tract, the largest human microbial reservoir, is highly dynamic. The gut microbes play essential roles in causing colorectal diseases. In the present study, we explored potential keystone taxa during the development of colorectal diseases in central China. Fecal samples of some patients were collected and were allocated to the adenoma (Group A), colorectal cancer (Group C), and hemorrhoid (Group H) groups. The 16S rRNA amplicon and shallow metagenomic sequencing (SMS) strategies were used to recover the gut microbiota. Microbial diversities obtained from 16S rRNA amplicon and SMS data were similar. Group C had the highest diversity, although no significant difference in diversity was observed among the groups. The most dominant phyla in the gut microbiota of patients with colorectal diseases were Bacteroidetes, Firmicutes, and Proteobacteria, accounting for >95% of microbes in the samples. The most abundant genera in the samples were <i>Bacteroides</i>, <i>Prevotella</i>, and <i>Escherichia/Shigella</i>, and further species-level and network analyses identified certain potential keystone taxa in each group. Some of the dominant species, such as <i>Prevotella copri</i>, <i>Bacteroides dorei</i>, and <i>Bacteroides vulgatus</i>, could be responsible for causing colorectal diseases. The SMS data recovered diverse antibiotic resistance genes of tetracycline, macrolide, and beta-lactam, which could be a result of antibiotic overuse. This study explored the gut microbiota of patients with three different types of colorectal diseases, and the microbial diversity results obtained from 16S rRNA amplicon sequencing and SMS data were found to be similar. However, the findings of this study are based on a limited sample size, which warrants further large-scale studies. The recovery of gut microbiota profiles in patients with colorectal diseases could be beneficial for future diagnosis and treatment with modulation of the gut microbiota. Moreover, SMS data can provide accurate species- and gene-level information, and it is economical. It can therefore be widely applied in future clinical metagenomic studies.
Project description:Phocaeicola vulgatus is one of the most abundant and ubiquitous bacterial species of the human gut microbiota, yet a comprehensive analysis of antibacterial toxin production by members of this species has not been reported. Here, we identify and characterize a previously undescribed antibacterial protein. This toxin, designated BcpT, is encoded on a small mobile plasmid that is largely confined to strains of the closely related species Phocaeicola vulgatus and Phocaeicola dorei. BcpT is unusual in that it requires cleavage at two distinct sites for activation, and we identify bacterial proteases that perform this activation. We further identify BcpT's receptor as the Lipid A-core glycan, allowing BcpT to target species of other Bacteroidales families. Exposure of cells to BcpT induces a response involving an unusual sigma/anti-sigma factor pair that is likely triggered by cell envelope stress, resulting in the expression of genes that partially protect cells from multiple antimicrobial toxins.
Project description:The incidence of the autoimmune disease, type 1 diabetes (T1D), has increased dramatically over the last half century in many developed countries and is particularly high in Finland and other Nordic countries. Along with genetic predisposition, environmental factors are thought to play a critical role in this increase. As with other autoimmune diseases, the gut microbiome is thought to play a potential role in controlling progression to T1D in children with high genetic risk, but we know little about how the gut microbiome develops in children with high genetic risk for T1D. In this study, the early development of the gut microbiomes of 76 children at high genetic risk for T1D was determined using high-throughput 16S rRNA gene sequencing. Stool samples from children born in the same hospital in Turku, Finland were collected at monthly intervals beginning at 4-6 months after birth until 2.2 years of age. Of those 76 children, 29 seroconverted to T1D-related autoimmunity (cases) including 22 who later developed T1D, the remaining 47 subjects remained healthy (controls). While several significant compositional differences in low abundant species prior to seroconversion were found, one highly abundant group composed of two closely related species, Bacteroides dorei and Bacteroides vulgatus, was significantly higher in cases compared to controls prior to seroconversion. Metagenomic sequencing of samples high in the abundance of the B. dorei/vulgatus group before seroconversion, as well as longer 16S rRNA sequencing identified this group as Bacteroides dorei. The abundance of B. dorei peaked at 7.6 months in cases, over 8 months prior to the appearance of the first islet autoantibody, suggesting that early changes in the microbiome may be useful for predicting T1D autoimmunity in genetically susceptible infants. The cause of increased B. dorei abundance in cases is not known but its timing appears to coincide with the introduction of solid food.
Project description:Changes in the gut microenvironment may influence the pathogenesis of autism spectrum disorders (ASD). Here, we investigated the composition of the gut microbiota and metabolites in children with ASD. Ninety-two children with ASD and 42 age-matched children exhibiting typical development (TD) were enrolled in the two-stage study. In the discovery stage, shotgun metagenomic sequencing and liquid chromatography-mass spectrometry (LC-MS) were performed simultaneously on fecal samples obtained from 43 children in the ASD group and 31 children in the TD group. Systematic bioinformatic analyses were performed to identify gut metabolites associated with altered gut microbiota composition. At the validation stage, differential metabolites were tested using LC-MS with an additional 49 and 11 children in the ASD and TD groups, respectively. Altered glutamate metabolites were found in the ASD group, along with a decline in 2-keto-glutaramic acid and an abundance of microbiota associated with glutamate metabolism. These changes in glutamate metabolism were correlated with lower levels of the highly abundant bacteria Bacteroides vulgatus and higher levels of the potentially harmful Eggerthella lenta and Clostridium botulinum. Lower gut cortisol levels have also been identified in the ASD group and associated with changes in gut microbiota glutamate metabolism. Finally, gut 2-keto-glutaramic acid was validated as a potential biomarker for ASD. The significant changes in the gut microenvironment in children with ASD may provide new insight into the cause of ASD and aid in the search for diagnostic and therapeutic approaches. IMPORTANCE Multiple lines of evidence suggest that the gut microbiota may play an important role in the pathogenesis of ASD, but the specific mechanism is still unclear. Through a comprehensive gut metagenomic and metabolome study of children with ASD, alterations in gut metabolite composition were found in children with ASD, and these alterations were linked to changes in gut microbiota composition. This may give us a deeper understanding of the role of gut microbiota in the pathogenesis of ASD.
Project description:<h4>Background</h4>A foodborne pathogen, Vibrio vulnificus, encounters normal microflora inhabiting the gut environments prior to causing fatal septicemia or gastroenteritis and should overcome the barriers derived from the gut commensals for successful infection. Its interactions with gut commensals during the infection process, however, have not yet been understood. In the present study, the effect of V. vulnificus on the community structures of gut microbiota in mice was examined.<h4>Results</h4>Analyses of microbiota in the fecal samples of mice that died due to V. vulnificus infection revealed the decreased abundance of bacteria belonged to Bacteroidetes, notably, the species Bacteroides vulgatus. In vitro coculturing of the two bacterial species resulted in the decreased survival of B. vulgatus. The antagonistic effect of V. vulnificus against B. vulgatus was found to be mediated by cyclo-Phe-Pro (cFP), one of the major compounds secreted by V. vulnificus. cFP-treated B. vulgatus showed collapsed cellular morphology with an undulated cell surface, enlarged periplasmic space, and lysed membranes, suggesting the occurrence of membrane disruption. The degree of membrane disruption caused by cFP was dependent upon the cellular levels of ObgE in B. vulgatus. Recombinant ObgE exhibited a high affinity to cFP at a 1:1 ratio. When mice were orally injected with cFP, their feces contained significantly reduced B. vulgatus levels, and their susceptibility to V. vulnificus infection was considerably increased.<h4>Conclusions</h4>This study demonstrates that V. vulnificus-derived cFP modulates the abundance of the predominant species among gut commensals, which made V. vulnificus increase its pathogenicity in the hosts. Video abstract.
Project description:Iron (Fe) deficiency affects an estimated 2 billion people worldwide, and Fe supplements are a common corrective strategy. The impact of Fe deficiency and Fe supplementation on the complex microbial community of the child gut was studied using in vitro colonic fermentation models inoculated with immobilized fecal microbiota. Chyme media (all Fe chelated by 2,2'-dipyridyl to 26.5 mg Fe L(-1) ) mimicking Fe deficiency and supplementation were continuously fermented. Fermentation effluent samples were analyzed daily on the microbial composition and metabolites by quantitative PCR, 16S rRNA gene 454-pyrosequencing, and HPLC. Low Fe conditions (1.56 mg Fe L(-1) ) significantly decreased acetate concentrations, and subsequent Fe supplementation (26.5 mg Fe L(-1) ) restored acetate production. High Fe following normal Fe conditions had no impact on the gut microbiota composition and metabolic activity. During very low Fe conditions (0.9 mg Fe L(-1) or Fe chelated by 2,2'-dipyridyl), a decrease in Roseburia spp./Eubacterium rectale, Clostridium Cluster IV members and Bacteroides spp. was observed, while Lactobacillus spp. and Enterobacteriaceae increased consistent with a decrease in butyrate (-84%) and propionate (-55%). The strong dysbiosis of the gut microbiota together with decrease in main gut microbiota metabolites observed with very low iron conditions could weaken the barrier effect of the microbiota and negatively impact gut health.
Project description:Human milk oligosaccharides (HMOs) are a mixture of structurally diverse carbohydrates that contribute to shape a healthy gut microbiota composition. The great diversity of the HMOs structures does not allow the attribution of specific prebiotic characteristics to single milk oligosaccharides. We analyze here the utilization of four disaccharides, lacto-N-biose (LNB), galacto-N-biose (GNB), fucosyl-?1,3-GlcNAc (3FN) and fucosyl-?1,6-GlcNAc (6FN), that form part of HMOs and glycoprotein structures, by the infant fecal microbiota. LNB significantly increased the total levels of bifidobacteria and the species Bifidobacterium breve and Bifidobacterium bifidum. The Lactobacillus genus levels were increased by 3FN fermentation and B. breve by GNB and 3FN. There was a significant reduction of Blautia coccoides group with LNB and 3FN. In addition, 6FN significantly reduced the levels of Enterobacteriaceae family members. Significantly higher concentrations of lactate, formate and acetate were produced in cultures containing either LNB or GNB in comparison with control cultures. Additionally, after fermentation of the oligosaccharides by the fecal microbiota, several Bifidobacterium strains were isolated and identified. The results presented here indicated that each, LNB, GNB and 3FN disaccharide, might have a specific beneficial effect in the infant gut microbiota and they are potential prebiotics for application in infant foods.