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1.
MAIT cell activation in adolescents is impacted by bile acid concentrations and body weight.
Mendler, A, Pierzchalski, A, Bauer, M, Röder, S, Sattler, A, Standl, M, Borte, M, von Bergen, M, Rolle-Kampczyk, U, Herberth, G
Clinical and experimental immunology. 2020;(2):199-213
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Abstract
Bile acids (BAs) are produced by liver hepatocytes and were recently shown to exert functions additional to their well-known role in lipid digestion. As yet it is not known whether the mucosal-associated invariant T (MAIT) cells, which represent 10-15% of the hepatic T cell population, are affected by BAs. The focus of the present investigation was on the association of BA serum concentration with MAIT cell function and inflammatory parameters as well as on the relationship of these parameters to body weight. Blood samples from 41 normal weight and 41 overweight children of the Lifestyle Immune System Allergy (LISA) study were analyzed with respect to MAIT cell surface and activation markers [CD107a, CD137, CD69, interferon (IFN)-γ, tumor necrosis factor (TNF)-α] after Escherichia coli stimulation, mRNA expression of promyelocytic leukemia zinc finger protein (PLZF) and major histocompatibility complex class I-related gene protein (MR1), the inflammatory markers C-reactive protein (CRP), interleukin (IL)-8 and macrophage inflammatory protein (MIP)-1α as well as the concentrations of 13 conjugated and unconjugated BAs. Higher body weight was associated with reduced MAIT cell activation and expression of natural killer cell marker (NKp80) and chemokine receptor (CXCR3). BA concentrations were positively associated with the inflammatory parameters CRP, IL-8 and MIP-1α, but were negatively associated with the number of activated MAIT cells and the MAIT cell transcription factor PLZF. These relationships were exclusively found with conjugated BAs. BA-mediated inhibition of MAIT cell activation was confirmed in vitro. Thus, conjugated BAs have the capacity to modulate the balance between pro- and anti-inflammatory immune responses.
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Prediagnostic Plasma Bile Acid Levels and Colon Cancer Risk: A Prospective Study.
Kühn, T, Stepien, M, López-Nogueroles, M, Damms-Machado, A, Sookthai, D, Johnson, T, Roca, M, Hüsing, A, Maldonado, SG, Cross, AJ, et al
Journal of the National Cancer Institute. 2020;(5):516-524
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Abstract
BACKGROUND Bile acids have been proposed to promote colon carcinogenesis. However, there are limited prospective data on circulating bile acid levels and colon cancer risk in humans. METHODS Associations between prediagnostic plasma levels of 17 primary, secondary, and tertiary bile acid metabolites (conjugated and unconjugated) and colon cancer risk were evaluated in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Bile acid levels were quantified by tandem mass spectrometry in samples from 569 incident colon cancer cases and 569 matched controls. Multivariable logistic regression analyses were used to estimate odds ratios (ORs) for colon cancer risk across quartiles of bile acid concentrations. RESULTS Positive associations were observed between colon cancer risk and plasma levels of seven conjugated bile acid metabolites: the primary bile acids glycocholic acid (ORquartile 4 vs quartile 1= 2.22, 95% confidence interval [CI] = 1.52 to 3.26), taurocholic acid (OR = 1.78, 95% CI = 1.23 to 2.58), glycochenodeoxycholic acid (OR = 1.68, 95% CI = 1.13 to 2.48), taurochenodeoxycholic acid (OR = 1.62, 95% CI = 1.11 to 2.36), and glycohyocholic acid (OR = 1.65, 95% CI = 1.13 to 2.40), and the secondary bile acids glycodeoxycholic acid (OR = 1.68, 95% CI = 1.12 to 2.54) and taurodeoxycholic acid (OR = 1.54, 95% CI = 1.02 to 2.31). By contrast, unconjugated bile acids and tertiary bile acids were not associated with risk. CONCLUSIONS This prospective study showed that prediagnostic levels of certain conjugated primary and secondary bile acids were positively associated with risk of colon cancer. Our findings support experimental data to suggest that a high bile acid load is colon cancer promotive.
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Associations between fecal bile acids, neutral sterols, and serum lipids in the KORA FF4 study.
Breuninger, TA, Wawro, N, Meisinger, C, Artati, A, Adamski, J, Peters, A, Grallert, H, Linseisen, J
Atherosclerosis. 2019;:1-8
Abstract
BACKGROUND AND AIMS Dyslipidemia is a major risk factor for cardiovascular disease, the leading cause of preventable death worldwide. As a result, a full understanding of the factors influencing dyslipidemia is urgently necessary. Bile acids have been recognized as regulators of lipid metabolism, and neutral sterols may influence serum lipid levels. Therefore, this analysis was conducted to better understand the relationship between bile acids, neutral sterols, and dyslipidemia. METHODS We examined cross-sectional associations between selected fecal metabolites and serum lipids or markers of dyslipidemia in 1387 participants of the KORA FF4 study using linear and logistic regression models. RESULTS We found positive associations between fecal bile acids and serum high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-c), total cholesterol, triglycerides and markers of dyslipidemia, though associations were seen most consistently with triglycerides and hypertriglyceridemia. We also found positive associations between fecal cholesterol and serum LDL-c, total cholesterol, triglycerides, hypertriglyceridemia and high serum total cholesterol, though only associations with triglycerides or hypertriglyceridemia remained significant after applying the Bonferroni correction. Unexpectedly, several fecal plant sterols were positively associated with serum lipids and the associated markers of dyslipidemia. However, many of these associations were no longer statistically significant after adjusting for multiple testing. CONCLUSIONS Our results provide insight into the role that bile acids may play in the development or progression of dyslipidemia. However, further confirmation of these results is warranted. Longitudinal and experimental studies are necessary to clarify the mechanisms behind these associations and to determine causality.
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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.
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Bile acid profiles over 5 years after gastric bypass and duodenal switch: results from a randomized clinical trial.
Risstad, H, Kristinsson, JA, Fagerland, MW, le Roux, CW, Birkeland, KI, Gulseth, HL, Thorsby, PM, Vincent, RP, Engström, M, Olbers, T, et al
Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2017;(9):1544-1553
Abstract
BACKGROUND Bile acids have been proposed as key mediators of the metabolic effects after bariatric surgery. Currently no reports on bile acid profiles after duodenal switch exist, and long-term data after gastric bypass are lacking. OBJECTIVE To investigate bile acid profiles up to 5 years after Roux-en-Y gastric bypass and biliopancreatic diversion with duodenal switch and to explore the relationship among bile acids and weight loss, lipid profile, and glucose metabolism. SETTINGS Two Scandinavian University Hospitals. METHODS We present data from a randomized clinical trial of 60 patients with body mass index 50-60 kg/m2 operated with gastric bypass or duodenal switch. Repeated measurements of total and individual bile acids from fasting serum during 5 years after surgery were performed. RESULTS Mean concentrations of total bile acids increased from 2.3 µmol/L (95% confidence interval [CI], -.1 to 4.7) at baseline to 5.9 µmol/L (3.5-8.3) 5 years after gastric bypass and from 1.0 µmol/L (95% CI, -1.4 to 3.5) to 9.5 µmol/L (95% CI, 7.1-11.9) after duodenal switch; mean between-group difference was -4.8 µmol/L (95% CI, -9.3 to -.3), P = .036. Mean concentrations of primary bile acids increased more after duodenal switch, whereas secondary bile acids increased proportionally across the groups. Higher levels of total bile acids at 5 years were associated with lower body mass index, greater weight loss, and lower total cholesterol. CONCLUSIONS Total bile acid concentrations increased substantially over 5 years after both gastric bypass and duodenal switch, with greater increases in total and primary bile acids after duodenal switch. (Surg Obes Relat Dis 2017;0:000-000.) © 2017 American Society for Metabolic and Bariatric Surgery. All rights reserved.
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The effects of colestilan versus placebo and sevelamer in patients with CKD 5D and hyperphosphataemia: a 1-year prospective randomized study.
Locatelli, F, Spasovski, G, Dimkovic, N, Wanner, C, Dellanna, F, Pontoriero, G
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2014;(5):1061-73
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Abstract
BACKGROUND This study compared the effects of short-term titrated colestilan (a novel non-absorbable, non-calcium, phosphate binder) with placebo, and evaluated the safety and efficacy of colestilan over 1 year compared with sevelamer, in patients with chronic kidney disease (CKD) 5D. METHODS This prospective multicentre study comprised a 4-week phosphate binder washout period, a 16-week short-term, flexible-dose, treatment period (including a 4-week placebo-controlled withdrawal period) and a 40-week extension treatment phase. RESULTS At Week 16 (the end of the 4-week placebo-controlled withdrawal period), serum phosphorus level was 0.43 mmol/L (1.32 mg/dL) lower with colestilan than placebo (P < 0.001; primary end point). Serum LDL-C level was also lower with colestilan than with placebo (P < 0.001). Both colestilan and sevelamer produced significant reductions from baseline in serum phosphorus levels (P < 0.001), maintained for 1 year, and the proportion of patients achieving target levels of ≤1.78 mmol/L (5.5 mg/dL) or ≤1.95 mmol/L (6.0 mg/dL) at study end were similar (65.3 and 73.3%, respectively, for colestilan, and 66.9 and 77.4%, respectively, for sevelamer). Serum calcium level remained stable in the colestilan group but tended to increase slightly in the sevelamer group (end-of-study increase of 0.035 mmol/L over baseline). Both binders produced similar reductions from baseline in LDL-C level (P < 0.001), and responder rates after 1 year, using a target of <1.83 mmol/L (70 mg/dL) or <2.59 mmol/L (100 mg/dL) were similar in both groups (50.7 and 85.3% for colestilan and 54.0 and 80.6% for sevelamer). Colestilan was generally well tolerated. CONCLUSIONS Colestilan is effective and safe for the treatment of hyperphosphataemia in patients with CKD 5D, and affords similar long-term phosphorus and cholesterol reductions/responder rates to sevelamer.
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Evaluation of colestilan in chronic kidney disease dialysis patients with hyperphosphataemia and dyslipidaemia: a randomized, placebo-controlled, multiple fixed-dose trial.
Locatelli, F, Dimkovic, N, Spasovski, G
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2013;(7):1874-88
Abstract
BACKGROUND Colestilan is a non-absorbed, non-calcium-based, phosphate binder. It also binds bile acids and reduces serum levels of low-density lipoprotein cholesterol (LDL-C). This study evaluated the efficacy of a range of fixed doses of colestilan compared with placebo for the control of serum phosphorus and LDL-C levels in patients with CKD stage 5 on dialysis. METHODS This was a multicentre, randomized, double-blind, placebo-controlled, multiple fixed-dose trial in which 642 patients with CKD stage 5 on dialysis who had both hyperphosphataemia and dyslipidaemia, were randomized to treatment with colestilan 3, 6, 9, 12 or 15 g/day or placebo for 12 weeks. The co-primary endpoints were the mean changes in serum phosphorus and the mean per cent change in LDL-C from baseline to Week 12. RESULTS A significantly greater mean reduction in serum phosphorus level from baseline to Week 12 than seen with placebo was seen with 9 g (-0.28 mmol/L) and pooled colestilan 12/15 g (-0.34 mmol/L). The per cent reduction in LDL-C level was significantly greater with colestilan 3, 6 and 9 g and pooled colestilan 12/15 g than with placebo (reduction ranged from 15.9 to 27.6% dependent on dose). Colestilan also reduced total cholesterol, oxidized LDL-C, HbA1c and uric acid levels, and did not increase serum calcium levels. Colestilan was generally well tolerated; the most common adverse events affected the gastrointestinal system. CONCLUSIONS Colestilan is an effective treatment for hyperphosphataemia, and provides beneficial effects on other metabolic parameters associated with cardiovascular risk, notably LDL-C.
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Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial.
Jones, ML, Martoni, CJ, Prakash, S
European journal of clinical nutrition. 2012;(11):1234-41
Abstract
BACKGROUND/OBJECTIVES The percentage of hypercholesterolemic individuals not reaching their LDL-cholesterol (LDL-C) goal remains high and additional therapeutic strategies should be evaluated. The objective of this study was to evaluate the cholesterol-lowering efficacy and mechanism of action of bile salt hydrolase-active Lactobacillus reuteri NCIMB 30242 capsules in hypercholesterolemic adults. SUBJECTS/METHODS A total of 127 subjects completed a randomized, double-blind, placebo-controlled, parallel-arm, multicenter study. Subjects were randomized to consume L. reuteri NCIMB 30242 capsules or placebo capsules over a 9-week intervention period. The primary outcome was LDL-C relative to placebo at the study end point. RESULTS L. reuteri NCIMB 30242 capsules reduced LDL-C by 11.64% (P<0.001), total cholesterol by 9.14%, (P<0.001), non-HDL-cholesterol (non-HDL-C) by 11.30% (P < 0.001) and apoB-100 by 8.41% (P = 0.002) relative to placebo. The ratios of LDL-C/HDL-cholesterol (HDL-C) and apoB-100/apoA-1 were reduced by 13.39% (P = 0.006) and 9.00% (P = 0.026), respectively, relative to placebo. Triglycerides and HDL-C were unchanged. High-sensitivity C-reactive protein and fibrinogen were reduced by 1.05 mg/l (P = 0.005) and 14.25% (P = 0.004) relative to placebo, respectively. Mean plasma deconjugated bile acids were increased by 1.00 nmol/l (P=0.025) relative to placebo, whereas plasma campesterol, sitosterol and stigmasterol were decreased by 41.5%, 34.2% and 40.7%, respectively. CONCLUSIONS The present results suggest that the deconjugation of intraluminal bile acids results in reduced absorption of non-cholesterol sterols and indicate that L. reuteri NCIMB 30242 capsules may be useful as an adjunctive therapy for treating hypercholesterolemia.
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Effect of bile acid sequestrants on glucose metabolism, hepatic de novo lipogenesis, and cholesterol and bile acid kinetics in type 2 diabetes: a randomised controlled study.
Beysen, C, Murphy, EJ, Deines, K, Chan, M, Tsang, E, Glass, A, Turner, SM, Protasio, J, Riiff, T, Hellerstein, MK
Diabetologia. 2012;(2):432-42
Abstract
AIMS/HYPOTHESIS The primary aim of this completed multicentre randomised, parallel, double-blind placebo-controlled study was to elucidate the mechanisms of glucose-lowering with colesevelam and secondarily to investigate its effects on lipid metabolism (hepatic de novo lipogenesis, cholesterol and bile acid synthesis). METHODS Participants with type 2 diabetes (HbA(1c) 6.7-10.0% [50-86 mmol/mol], fasting glucose <16.7 mmol/l, fasting triacylglycerols <3.9 mmol/l and LDL-cholesterol >1.55 mmol/l) treated with diet and exercise, sulfonylurea, metformin or a combination thereof, were randomised by a central coordinator to either 3.75 g/day colesevelam (n = 30) or placebo (n = 30) for 12 weeks at three clinical sites in the USA. The primary measure was the change from baseline in glucose kinetics with colesevelam compared to placebo treatment. Fasting and postprandial glucose, lipid and bile acid pathways were measured at baseline and post-treatment using stable isotope techniques. Plasma glucose, insulin, total glucagon-like peptide-1 (GLP-1), total glucose-dependent insulinotropic polypeptide (GIP), glucagon and fibroblast growth factor-19 (FGF-19) concentrations were measured during the fasting state and following a meal tolerance test. Data was collected by people blinded to treatment. RESULTS Compared with placebo, colesevelam improved HbA(1c) (mean change from baseline of 0.3 [SD 1.1]% for placebo [n = 28] and -0.3 [1.1]% for colesevelam [n = 26]), glucose concentrations, fasting plasma glucose clearance and glycolytic disposal of oral glucose. Colesevelam did not affect gluconeogenesis or appearance rate (absorption) of oral glucose. Fasting endogenous glucose production and glycogenolysis significantly increased with placebo but were unchanged with colesevelam (treatment effect did not reach statistical significance). Compared with placebo, colesevelam increased total GLP-1 and GIP concentrations and improved HOMA-beta cell function while insulin, glucagon and HOMA-insulin resistance were unchanged. Colesevelam increased cholesterol and bile acid synthesis and decreased FGF-19 concentrations. However, no effect was seen on fractional hepatic de novo lipogenesis. CONCLUSIONS/INTERPRETATION Colesevelam, a non-absorbed bile acid sequestrant, increased circulating incretins and improved tissue glucose metabolism in both the fasting and postprandial states in a manner different from other approved oral agents. TRIAL REGISTRATION ClinicalTrials.gov NCT00596427 FUNDING The study was funded by Daiichi Sankyo.
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Colestilan monotherapy significantly improves glycaemic control and LDL cholesterol levels in patients with type 2 diabetes: a randomized double-blind placebo-controlled study.
Kondo, K, Kadowaki, T
Diabetes, obesity & metabolism. 2010;(3):246-51
Abstract
AIM: To evaluate the plasma glucose-reducing activity and safety of colestilan, a bile acid sequestrant, in patients with type 2 diabetes. METHODS Patients with fasting plasma glucose (FPG) 7.2-11.1 mmol/l and HbA (1c)> or =7.0% were randomly allocated in double-blind manner to receive colestilan or placebo therapy for 12 weeks. RESULTS A total of 183 patients entered the double-blind treatment phase. At 12 weeks, colestilan significantly reduced HbA (1c) and FPG vs. placebo by 0.9% and 1.2 mmol/l respectively (both p < 0.001). A significant (p < 0.001) 22.5% reduction of LDL cholesterol was also observed in the 172 patients evaluated (colestilan group: n = 86; placebo group: n = 86). However, no significant reduction of fasting insulin was observed (p = 0.087). No incidence of hypoglycaemia was reported in this study. CONCLUSION Colestilan improved glycaemic control and reduced LDL cholesterol levels in patients with type 2 diabetes.