1.
Faecal bile acids and colonic bile acid membrane receptor correlate with symptom severity of diarrhoea-predominant irritable bowel syndrome: A pilot study.
Wei, W, Wang, H, Zhang, Y, Zhang, Y, Niu, B, Chen, S, Zhang, W, Yao, S
Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver. 2021;(9):1120-1127
Abstract
AIMS: To compare both the faecal bile acids (BAs) and the levels of two bile acid receptors, Takeda G protein-coupled receptor 5 (TGR5) and vitamin D receptor (VDR), in the colonic mucosa between patients with irritable bowel syndrome with predominant diarrhea (IBS-D) and healthy controls, and explore the correlations among clinical characteristics, bile acid receptors expression, and BAs. METHODS The severity of abdominal pain and diarrhoea was assessed in IBS-D patients using validated questionnaires, faecal BAs were measured by ultraperformance liquid chromatography coupled to tandem mass spectrometry, and rectosigmoid biopsies were taken for the analyses of TGR5 and VDR expression using immunohistochemistry. RESULTS The level of TGR5 immunoreactivity in rectosigmoid mucosal biopsies was significantly higher in IBS-D patients than in controls, while the VDR immunoreactivity displayed no significant difference between patients and controls. The patients with more severe or more frequent abdominal pain had significantly higher TGR5 level. Faecal primary BAs were significantly increased in IBS-D patients and were positively correlated with the severity of diarrhoea. The level of TGR5 was positively associated with primary BAs and negatively associated with secondary BAs among all participants providing both mucosal and stool samples. CONCLUSIONS Colonic mucosal TGR5 protein expression and faecal bile acids were correlated with the symptom severity of IBS-D patients.
2.
Analyses of gut microbiota and plasma bile acids enable stratification of patients for antidiabetic treatment.
Gu, Y, Wang, X, Li, J, Zhang, Y, Zhong, H, Liu, R, Zhang, D, Feng, Q, Xie, X, Hong, J, et al
Nature communications. 2017;(1):1785
Abstract
Antidiabetic medication may modulate the gut microbiota and thereby alter plasma and faecal bile acid (BA) composition, which may improve metabolic health. Here we show that treatment with Acarbose, but not Glipizide, increases the ratio between primary BAs and secondary BAs and plasma levels of unconjugated BAs in treatment-naive type 2 diabetes (T2D) patients, which may beneficially affect metabolism. Acarbose increases the relative abundances of Lactobacillus and Bifidobacterium in the gut microbiota and depletes Bacteroides, thereby changing the relative abundance of microbial genes involved in BA metabolism. Treatment outcomes of Acarbose are dependent on gut microbiota compositions prior to treatment. Compared to patients with a gut microbiota dominated by Prevotella, those with a high abundance of Bacteroides exhibit more changes in plasma BAs and greater improvement in metabolic parameters after Acarbose treatment. Our work highlights the potential for stratification of T2D patients based on their gut microbiota prior to treatment.