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- Haange, S. B., et al.
(författare)
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Ring Trial on Quantitative Assessment of Bile Acids Reveals a Method- and Analyte-Specific Accuracy and Reproducibility
- 2022
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Ingår i: Metabolites. - : MDPI AG. - 2218-1989. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Bile acids are a key mediator of the molecular microbiome-host interaction, and various mass spectrometry-based assays have been developed in the recent decade to quantify a wide range of bile acids. We compare existing methodologies to harmonize them. Methodology for absolute quantification of bile acids from six laboratories in Europe were compared for the quantification of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) and conjugated products glycocholic acid (GCA) and taurocholic acid (TCA). For the bacterially modified secondary bile acids, the quantification of deoxycholic acid (DCA) and lithocholic acid (LCA) was compared. For the murine bile acids, we used the primary muricholic acids (alpha-MCA and, beta-MCA) and the intestinally produced secondary bile acid muricholic (omega-MCA). The standards were spiked into methanol:water (1:1) mix as well as in human and murine serum at either low concentration range (150-3000 nM) or high concentration range (1500-40,000 nM). The precision was better for higher concentrations. Measurements for the hydrophobic unconjugated bile acids LCA and omega-MCA were the most challenging. The quality assessments were generally very similar, and the comprehensive analyses demonstrated that data from chosen locations can be used for comparisons between studies.
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- Mueller, M., et al.
(författare)
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Ursodeoxycholic acid exerts farnesoid X receptor-antagonistic effects on bile acid and lipid metabolism in morbid obesity
- 2015
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Ingår i: Journal of Hepatology. - 0168-8278. ; 62:6, s. 1398-1404
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Bile acids (BAs) are major regulators of hepatic BA and lipid metabolism but their mechanisms of action in non-alcoholic fatty liver disease (NAFLD) are still poorly understood. Here we aimed to explore the molecular and biochemical mechanisms of ursodeoxycholic acid (UDCA) in modulating the cross-talk between liver and visceral white adipose tissue (vWAT) regarding BA and cholesterol metabolism and fatty acid/lipid partitioning in morbidly obese NAFLD patients. Methods: In this randomized controlled pharmacodynamic study, we analyzed serum, liver and vWAT samples from 40 well-matched morbidly obese patients receiving UDCA (20 mg/ kg/day) or no treatment three weeks prior to bariatric surgery. Results: Short term UDCA administration stimulated BA synthesis by reducing circulating fibroblast growth factor 19 and farnesoid X receptor (FXR) activation, resulting in cholesterol 7 alpha-hydroxylase induction mirrored by elevated C4 and 7 alpha-hydroxycholesterol. Enhanced BA formation depleted hepatic and LDL-cholesterol with subsequent activation of the key enzyme of cholesterol synthesis 3-hydroxy-3-methylglutaryl-CoA reductase. Blunted FXR anti-lipogenic effects induced lipogenic stearoyl-CoA desaturase (SCD) in the liver, thereby increasing hepatic triglyceride content. In addition, induced SCD activity in vWAT shifted vWAT lipid metabolism towards generation of less toxic and more lipogenic monounsaturated fatty acids such as oleic acid. Conclusion: These data demonstrate that by exerting FXR-antagonistic effects, UDCA treatment in NAFLD patients strongly impacts on cholesterol and BA synthesis and induces neutral lipid accumulation in both liver and vWAT. (C) 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.
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- Silbernagel, Gunther, et al.
(författare)
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High cholesterol absorption is associated with increased cardiovascular risk in haemodialysis patients : insights from the AURORA study
- 2022
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Ingår i: European Journal of Preventive Cardiology. - : Oxford University Press. - 2047-4873 .- 2047-4881. ; 29:13, s. 1731-1739
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Tidskriftsartikel (refereegranskat)abstract
- Aims Statin treatment did not reduce the risk of cardiovascular events in haemodialysis patients in the 4D and AURORA trials. Post hoc analyses in the 4D study suggested that high cholesterol absorption was associated with increased cardiovascular risk and that atorvastatin would reduce cardiovascular risk in haemodialysis patients with low cholesterol absorption but not in those with high cholesterol absorption. Methods and results AURORA is a randomized, double-blind, placebo-controlled, multi-centre trial in haemodialysis patients. The participants were randomly assigned to receive either rosuvastatin, 10 mg daily, or a matching placebo. There was a follow-up for cardiovascular death with a median duration of 3.9 years. The cholestanol and lathosterol to cholesterol ratios were used to estimate cholesterol absorption and synthesis, respectively. Measurement of non-cholesterol sterols was available in 2332 participants of the 2733 patients included in the primary analysis of the AURORA study. A total of 598 participants died from cardiovascular diseases. The 3rd vs. the 1st tertile of the cholestanol-to-cholesterol ratio was significantly associated with increased risk of cardiovascular death [hazard ratio, HR (95% confidence interval, CI) = 1.36 (1.11-1.65)] in univariate (P = 0.002) and multivariate models (P = 0.034). In contrast, the 3rd vs. the 1st tertile of the lathosterol-to-cholesterol ratio was significantly associated with decreased risk of cardiovascular death [HR (95% CI) = 0.81 (0.67-0.99)] in univariate (P = 0.041) and multivariate (P = 0.019) models. There was no significant interaction between the cholestanol and lathosterol to cholesterol tertiles and treatment group in predicting cardiovascular death. Conclusion The present data from the AURORA study confirm that high cholesterol absorption is associated with increased cardiovascular risk in haemodialysis patients. Assessment of the individual cholesterol absorption rate to guide initiation of statin treatment is not supported by the findings in the AURORA study.
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