Project description:The levels of fasting-state serum bile acids (BAs) in individuals with polycystic ovary syndrome (PCOS) differ from those of control subjects. However, there is a lack of research on the BAs profile in lean women with PCOS and whether these changes are linked to the host metabolism. Therefore, our objective was to investigate the synthesis and metabolism of serum BAs in lean women with PCOS and assess the correlation between BAs and clinical characteristics. This study employed a cross-sectional design of lean women with PCOS (n = 240) in comparison to a control group (n = 80) consisting of healthy lean women. The findings revealed significant increases in the levels of non-12-OH BAs and chenodeoxycholic acid (CDCA)% (both P < 0.05) in lean women with PCOS. Additionally, a positive correlation was observed between CDCA% and total testosterone (T) (r = 0.130, P = 0.044) and free androgen index (FAI) (r = 0.153, P = 0.019). Furthermore, a decreased ratio of cholic acid/chenodeoxycholic acid (CA/CDCA) (P < 0.001) was observed in lean women with PCOS, suggesting the depletion or downregulation of CYP8B1. Receiver operating characteristic curve analysis indicated that the combination of CDCA/CA and DHEAS could potentially be used as a characteristic factor for PCOS in lean women. It is possible that enzymatic modifications in the liver could play a role in regulating hyperandrogenism in this specific subgroup of lean women with PCOS.
Project description:Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammatory disorder of the gastrointestinal tract that arises due to complex interactions between host genetic risk factors, environmental factors, and a dysbiotic gut microbiota. Although metagenomic approaches have attempted to characterise the dysbiosis occurring in IBD, the precise mechanistic pathways interlinking the gut microbiota and the intestinal mucosa are still yet to be unravelled. To deconvolute these complex interactions, a more reductionist approach involving microbial metabolites has been suggested. Bile acids have emerged as a key class of microbiota-associated metabolites that are perturbed in IBD patients. In recent years, metabolomics studies have revealed a consistent defect in bile acid metabolism with an increase in primary bile acids and a reduction in secondary bile acids in IBD patients. This review explores the evolving evidence that specific bile acid metabolites interact with intestinal epithelial and immune cells to contribute to the inflammatory milieu seen in IBD. Furthermore, we summarise evidence linking bile acids with intracellular pathways that are known to be relevant in IBD including autophagy, apoptosis, and the inflammasome pathway. Finally, we discuss how novel experimental and bioinformatics approaches could further advance our understanding of the role of bile acids and inform novel therapeutic strategies in IBD.
Project description:BackgroundVascular calcification is common among patients with chronic kidney disease (CKD), and it is associated with all-cause and cardiovascular disease mortality. Deoxycholic acid, a metabolite of circulating bile acids, is elevated in CKD and induces vascular mineralization and osteogenic differentiation in animal models.Study designCohort analysis of clinical trial participants.Setting & participants112 patients with moderate to severe CKD (estimated glomerular filtration rate, 20-45mL/min/1.73m2) who participated in a randomized controlled study to examine the effects of phosphate binders on vascular calcification.PredictorSerum deoxycholic acid concentration.OutcomesBaseline coronary artery calcification (CAC) volume score and bone mineral density (BMD) and change in CAC volume score and BMD after 9 months.MeasurementsDeoxycholic acid was assayed in stored baseline serum samples using liquid chromatography-tandem mass spectrometry, CAC was measured using a GE-Imitron C150 scanner, and BMD was determined using computed tomographic scans of the abdomen with calibrated phantom of known density.ResultsHigher serum deoxycholic acid concentrations were significantly correlated with greater baseline CAC volume and lower baseline BMD. After adjusting for demographics, coexisting illness, body mass index, estimated glomerular filtration rate, and concentrations of circulating markers of mineral metabolism, including serum calcium, phosphorus, vitamin D, parathyroid hormone, and fibroblast growth factor 23, a serum deoxycholic acid concentration > 58ng/mL (the median) was positively associated with baseline CAC volume (β=0.71; 95% CI, 0.26-1.16; P=0.003) and negatively associated with baseline BMD (β = -20.3; 95% CI, -1.5 to -39.1; P=0.04). Serum deoxycholic acid concentration > 58ng/mL was not significantly associated with change in CAC volume score after 9 months (β=0.06; 95% CI, -0.09 to 0.21; P=0.4). The analysis for the relationship between baseline deoxycholic acid concentrations and change in BMD after 9 months was not statistically significant, but was underpowered.LimitationsThe use of nonfasting serum samples is a limitation because deoxycholic acid concentrations may vary based on time of day and dietary intake. Few trial participants with complete data to evaluate the change in CAC volume score (n=75) and BMD (n=59). No data for changes in deoxycholic acid concentrations over time.ConclusionsAmong patients with moderate to severe CKD, higher serum deoxycholic acid concentrations were independently associated with greater baseline CAC volume score and lower baseline BMD.
Project description:Clostridium scindens biotransforms primary bile acids into secondary bile acids, and is correlated with inhibition of Clostridium difficile growth in vivo. The aim of the current study was to determine how C. scindens regulates C. difficile growth in vitro and if these interactions might relate to the regulation of gut microbiome structure in vivo. The bile acid 7α-dehydroxylating gut bacteria, C. scindens and C. sordellii, were found to secrete the tryptophan-derived antibiotics, 1-acetyl-β-carboline and turbomycin A, respectively. Both antibiotics inhibited growth of C. difficile and other gut bacteria. The secondary bile acids, deoxycholic acid and lithocholic acid, but not cholic acid, enhanced the inhibitory activity of these antibiotics. These antibiotics appear to inhibit cell division of C. difficile. The results help explain how endogenously synthesized antibiotics and secondary bile acids may regulate C. difficile growth and the structure of the gut microbiome in health and disease.
Project description:Obeticholic acid (OCA) is a semisynthetic bile acid (BA) analog and potent farnesoid X receptor agonist approved to treat cholestasis. We evaluated the biodistribution and metabolism of OCA administered to carbon tetrachloride-induced cirrhotic rats. This was to ascertain if plasma and hepatic concentrations of OCA are potentially more harmful than those of endogenous BAs. After administration of OCA (30 mg/kg), we used liquid chromatography-mass spectrometry to measure OCA, its metabolites, and BAs at different timepoints in various organs and fluids. Plasma and hepatic concentrations of OCA and BAs were higher in cirrhotic rats than in controls. OCA and endogenous BAs had similar metabolic pathways in cirrhotic rats, although OCA hepatic and intestinal clearance were lower than in controls. BAs' qualitative and quantitative compositions were not modified by a single administration of OCA. In all the matrices studied, OCA concentrations were significantly lower than those of endogenous BAs, potentially much more cytotoxic.
Project description:The present experiment was conducted to determine the effect of bile acids (BAs) supplementation on growth performance, BAs profile, fecal microbiome, and serum metabolomics in growing-finishing pigs. A total of 60 pigs [Duroc × (Landrace × Yorkshire)] with an average body weight of 27.0 ± 1.5 kg were selected and allotted into one of 2 groups (castrated male to female ratio = 1:1), with 10 replicates per treatment and 3 pigs per replicate. The 2 treatments were the control group (control) and a porcine bile extract-supplemented group dosed at 0.5 g/kg feed (BA). After a 16-wk treatment, growth performance, BAs profiles in serum and feces, and fecal microbial composition were determined. An untargeted metabolomics approach using gas chromatography with a time-of-flight mass spectrometer was conducted to identify the metabolic pathways and associated metabolites in the serum of pigs. We found that BAs supplementation had no effect on the growth performance of the growing-finishing pig. However, it tended to increase the gain-to-feed ratio for the whole period (P = 0.07). BAs supplementation resulted in elevated serum concentrations of secondary bile acids, including hyodeoxycholic acid (HDCA), glycoursodeoxycholic acid, and tauro-hyodeoxycholic acid, as well as fecal concentration of HDCA (P < 0.05). Fecal microbiota analysis revealed no differences in alpha and beta diversity indices or the relative abundance of operational taxonomic units (OTUs) at both phylum and genus levels between groups. Metabolic pathway analysis revealed that the differential metabolites between control and BA groups are mainly involved in purine metabolism, ether lipid metabolism, glycerophospholipid metabolism, and amino sugar and nucleotide sugar metabolism, as well as primary bile acid biosynthesis. Our findings indicate that BAs supplementation tended to improve the feed efficiency, and significantly altered the BA profile in the serum and feces of growing-finished pigs, regardless of any changes in the gut microbial composition. The altered metabolic pathways could potentially play a vital role in improving the feed efficiency of growing-finished pigs with BAs supplementation.
Project description:Bile acid diarrhea (BAD) is usually seen in patients with ileal Crohn's disease or ileal resection. However, 25% to 50% of patients with functional diarrhea or diarrhea-predominant irritable bowel syndrome (IBS-D) also have evidence of BAD. It is estimated that 1% of the population may have BAD. The causes of BAD include a deficiency in fibroblast growth factor 19 (FGF-19), a hormone produced in enterocytes that regulates hepatic bile acid (BA) synthesis. Other potential causes include genetic variations that affect the proteins involved in BA enterohepatic circulation and synthesis or in the TGR5 receptor that mediates the actions of BA in colonic secretion and motility. BAs enhance mucosal permeability, induce water and electrolyte secretion, and accelerate colonic transit partly by stimulating propulsive high-amplitude colonic contractions. There is an increased proportion of primary BAs in the stool of patients with IBS-D, and some changes in the fecal microbiome have been described. There are several methods of diagnosing BAD, such as (75)selenium homotaurocholic acid test retention, serum C4, FGF-19, and fecal BA measurement; presently, therapeutic trials with BA sequestrants are most commonly used for diagnosis. Management involves the use of BA sequestrants including cholestyramine, colestipol, and colesevelam. FXR agonists such as obeticholic acid constitute a promising new approach to treating BAD.
Project description:An improved ultra performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) method was established for the simultaneous analysis of various bile acids (BA) and applied to investigate liver BA content in C57BL/6 mice fed 1% cholic acid (CA), 0.3% deoxycholic acid (DCA), 0.3% chenodeoxycholic acid (CDCA), 0.3% lithocholic acid (LCA), 3% ursodeoxycholic acid (UDCA), or 2% cholestyramine (resin). Results indicate that mice have a remarkable ability to maintain liver BA concentrations. The BA profiles in mouse livers were similar between CA and DCA feedings, as well as between CDCA and LCA feedings. The mRNA expression of Cytochrome P450 7a1 (Cyp7a1) was suppressed by all BA feedings, whereas Cyp7b1 was suppressed only by CA and UDCA feedings. Gender differences in liver BA composition were observed after feeding CA, DCA, CDCA, and LCA, but they were not prominent after feeding UDCA. Sulfation of CA and CDCA was found at the 7-OH position, and it was increased by feeding CA or CDCA more in male than female mice. In contrast, sulfation of LCA and taurolithocholic acid (TLCA) was female-predominant, and it was increased by feeding UDCA and LCA. In summary, the present systematic study on BA metabolism in mice will aid in interpreting BA-mediated gene regulation and hepatotoxicity.
Project description:BackgroundWe have previously performed a Genome Wide Association and linkage study that indicated a new disease triggering mechanism involving amino acid metabolism and nutrient sensing signaling pathways.ObjectiveThe aim of this study was to investigate if plasma amino acid levels differed among children with celiac disease compared with disease controls.Materials and methodsFasting plasma samples from 141 children with celiac disease and 129 non-celiac disease controls, were analyzed for amino acid levels by liquid chromatography-tandem mass spectrometry (LC/MS). A general linear model using age and experimental effects as covariates was used to compare amino acid levels between children with a diagnosis of celiac disease and controls.ResultsSeven out of twenty-three analyzed amino acids were elevated in children with celiac disease compared with controls (tryptophan, taurine, glutamic acid, proline, ornithine, alanine and methionine). The significance of the individual amino acids do not survive multiple correction, however, multivariate analyses of the amino acid profile showed significantly altered amino acid levels in children with celiac disease overall and after correction for age, sex and experimental effects (p = 8.4 × 10-8).ConclusionThese findings support the idea that amino acids could influence systemic inflammation and play a possible role in disease pathogenesis.
Project description:Chemotherapeutic agents can reduce bone marrow (BM) activity, causing myelosuppression, a common life-threatening complication of cancer treatment. It is challenging to predict the patients in whom prolonged myelosuppression will occur, resulting in a delay or discontinuation of the treatment protocol. An early indicator of recovery from myelosuppression would thus be highly beneficial in clinical settings. In this study, bile acids (BAs) were highly increased in the systemic circulation as a natural response during recovery from myelosuppression, supporting regeneration of BM cells. BA levels in the blood of pediatric cancer patients and mice treated with chemotherapeutic agents were increased, in synchrony with early proliferation of BM cells and recovery from myelosuppression. In a mouse model of altered BA composition, Cyp8b1 knockout mice, a subset of mice recovered poorly after chemotherapy. The poor recovery correlated with low levels and changes in composition of BAs in the liver and systemic circulation. Conversely, BA supplementation in chemotherapy-treated wild-type mice resulted in significantly improved recovery. The results suggest that part of the mechanism by which BAs support recovery is the suppression of endoplasmic reticulum stress pathways in expanding and recovering hematopoietic cells. The findings propose a novel role of BAs as early markers of recovery and active components of the recovery process after chemotherapy.