Project description:The search for factors beyond the radiotherapy dose that could identify patients more at risk of developing radio-induced toxicity is essential to establish personalised treatment protocols for improving the quality-of-life of survivors. To investigate the role of the intestinal microbiota in the development of radiotherapy-induced gastrointestinal toxicity, the MicroLearner observational cohort study characterised the intestinal microbiota of 136 (discovery) and 79 (validation) consecutive prostate cancer patients at baseline radiotherapy. Gastrointestinal toxicity was assessed weekly during RT using CTCAE. An average grade >1.3 over time points was used to identify patients suffering from persistent acute toxicity (endpoint). The intestinal microbiota of patients was quantified from the baseline faecal samples using 16S rRNA gene sequencing technology.
Project description:Application of a mass spectrometry -based approach to assess the gut microbiota composition and the associated metaproteomic functionality in patients with intestinal COVID-19 infection
Project description:Background: Hypertension is one of the most common metabolic diseases in the elderly and its pathogenesis is associated with microbiota dysbiosis. Recent evidence suggests that oral microbiota dysbiosis is also an important factor in the development of hypertension. However, the relationship between hypertension and oral flora in the elderly has not been adequately investigated. Objective: The aim of this cross-sectional study was to investigate the structure of the oral microbiota and its correlation with hypertension in elderly hypertensive patients. To provide new ideas for the prevention and treatment of hypertension. Methods: 206 subjects aged 60 ~ 89 years were selected and divided into normal (CON) and hypertensive (HTN) groups, according to the 2018 Chinese Guidelines for the Management of Hypertension. The oral microbiome composition of saliva samples was determined by 16S rRNA gene sequencing. Results: Although there was no significant difference in α and β diversity between the two groups, systolic and diastolic blood pressure were the most important factors influencing the structure of the oral microbiota. At the phylum level, the relative abundance of the spirochete phylum and the mutualistic bacterial phylum was higher in the HT group than in the CON group (p < 0.05). Diastolic blood pressure was negatively correlated with Streptococcus. Furthermore, we analyzed HTN patients with 120 mmHg<systolic blood pressure<160 mmHg and systolic blood pressure>160 mmHg separately and found that the abundance of Saccharibacteria_(TM7) was significantly increased in the HTN_2 group. Conclusions: Our study identified specific oral microbiota in elderly hypertensive patients, confirming the relationship between oral microbiota and hypertension. This enhances our understanding of the important role of oral microbiota in the pathogenesis of hypertension and accumulates more evidence for microbial involvement in the development of hypertension.
Project description:Intestinal microbial dysbiosis is associated with Crohn’s disease (CD). However, the mechanisms leading to the chronic mucosal inflammation that characterizes this disease remain unclear. To evaluate causality and mechanisms of disease, we conducted a systems level study of the interactions between the gut microbiota and host in new-onset pediatric patients. We report an altered host proteome in CD patients indicative of impaired mitochondrial functions. A downregulation of mitochondrial proteins implicated in H2S detoxification was observed, while the relative abundance of H2S microbial producers was increased. Network correlation analysis identified Atopobium parvulum as the central hub of H2S producers. Gnotobiotic and conventionalized colitis-susceptible interleukin-10-deficient (Il10-/-) mice demonstrated that A. parvulum induced colitis, a phenotype requiring the presence of the intestinal microbiota. Administration of bismuth, a H2S scavenger, prevented A. parvulum-induced colitis in Il10-/- mice. This study identified host-microbiota interactions that are disturbed in CD patients providing mechanistic insights on CD pathogenesis.
Project description:Inappropriate cross talk between mammals and their gut microbiota may trigger intestinal inflammation and drive extra-intestinal immune-mediated diseases. Studies with germ-free or gnotobiotic animals represent the gold standard for research on bacterial-host interaction but they are not readily accessible to the wide scientific community. We aimed at refining a protocol that in a robust manner would deplete murine intestinal microbiota and prove to have significant biologic validity. Previously published protocols for depleting mice of their intestinal microbiota by administering broad-spectrum antibiotics in drinking water were difficult to reproduce. We show that twice daily delivery of antibiotics by gavage depleted mice of their cultivable fecal microbiota and reduced the fecal bacterial DNA load by approximately 400 fold while ensuring the animals’ health. Mice subjected to the protocol for 17 days displayed enlarged ceca, reduced Peyer’s patches and small spleens. Antibiotic treatment significantly reduced the expression of antimicrobial factors and altered the expression of 517 genes in total in the colonic epithelium. Genes involved in cell cycle were significantly altered concomitant with reduced epithelial proliferative activity in situ assessed by Ki-67 expression, suggesting that commensal microbiota drives cellular proliferation in colonic epithelium. We present a robust protocol for depleting mice of their cultivatable intestinal microbiota with antibiotics by gavage and show that the biological effect of this depletion is phenotypic characteristics and epithelial gene expression profile similar to those of germ-free mice. Comparison of genome-wide gene expression of colon intestinal epithelial cells from mice subjected to microbiota depletion protocol against to control mice.
Project description:Interventions: An observational study at the Dutch Screening for Breast Cancer will be performed in 66 postmenopausal women without breast cancer. By acquiring insight into the intestinal microbiota composition of postmenopausal women without breast cancer, a control group will be set up for already existing research lines in microbiota research in breast cancer patients at MUMC+. Fecal samples and questionnaires will be collected. The intestinal microbiota composition and absolute abundance of the fecal samples will be analyzed by with 16S rRNA Next Generation Sequencing (NGS) with subsequent qPCR to convert relative abundance to absolute abundance.
Primary outcome(s): The primary endpoints include the microbiota composition.
Study Design: N/A , unknown, Other
Project description:Objective: Roux-Y gastric bypass (RYGB) surgery is a last treatment resort to induce substantial and sustained weight loss in severe obesity. The anatomical rearrangement affects the intestinal microbiota but so far, little information is available how it interferes with microbial functionality and microbial-host interaction independent from weight loss. Design: A RYGB rat model was utilized and compared to sham-operated controls which were kept at matched body weight as RYGB animals by food restriction. We assessed microbial taxonomy by 16S rRNA gene sequencing and functional activity by metaproteomics and metabolomics on microbiota samples collected separately from the ileum, the cecum as well as the colon and separately analysed the lumen and mucus associated microbiota. Results: Altered gut architecture in RYGB strongly affected the occurrence of Actinobacteria, especially Bifidobacteriaceae and Proteobacteria which were increased, whereas Firmicutes were decreased, although Streptococcaceae and Clostridium perfringens were observed at higher abundances. A decrease of conjugated as well as secondary bile acids was observed in the RYGB-gut lumen. In addition the arginine biosynthesis pathway in the microbiota was altered, indicated by the changes in abundance of upstream metabolites and enzymes, resulting in lower levels of arginine and higher levels of aspartate in the colon after RYGB. Conclusion: The anatomical rearrangement in RYGB affects microbiota composition and functionality by changes in amino acid and bile acid metabolism, independent of weight loss. The shift in microbiota taxonomic structure after RYGB may be mediated by the resulting change in composition of the bile acid pool in the gut lumen.
Project description:Arginase 1 (Arg1), which converts L-arginine into ornithine and urea, exerts pleiotropic immunoregulatory effects. Patients with inflammatory bowel disease (IBD) show an enhanced expression and activity of Arg1 in the intestinal (sub-)mucosa, but the function of Arg1 in IBD remains poorly characterized. Here, we found that Arg1 expression correlates with the degree of inflammation in colitic tissues of IBD patients. In mice with - experimental colitis Arg1 was upregulated in an IL-4-/IL-13- and intestinal microbiota-dependent manner. Tie2-Cre+/-Arg1fl/fl mice lacking Arg1 in hematopoietic and endothelial cells recovered faster from colitis than Arg1-expressing littermates. This correlated with decreased vessel density, compositional changes in the intestinal microbiota, diminished infiltration by myeloid cellsand an accumulation of intraluminal polyamines that are associated with epithelial healing. Dietary L-arginine restriction abolished the protective effect of Arg1-deletion, suggesting that protection is related to an increased availability of L-arginine. Fecal microbiota transfers from Tie2-Cre+/-Arg1fl/fl mice into wildtype recipients restored the protective, anti-inflammatory phenotype while transfers from wildtype littermates into Arg1-deficient mice prevented the accelerated recovery from colitis. Thus, altered intestinal microbiota and metabolic products in Tie2-Cre+/-Arg1fl/fl mice account for the accelerated resolution from colitis in the absence of Arg1. Subsequently, L-arginine serves as novel therapeutic and diagnostic target for clinical intervention in IBD patients.