Bile acid sequestrants: Mechanisms of action on bile acid and cholesterol metabolism

1991 ◽  
Vol 40 (1) ◽  
pp. S53-S58 ◽  
Author(s):  
K. Einarsson ◽  
S. Ericsson ◽  
S. Ewerth ◽  
E. Reihn�r ◽  
M. Rudling ◽  
...  
Keyword(s):  
Bile Acid ◽  
Cholesterol Metabolism ◽  
Mechanisms Of Action ◽  
Bile Acid Sequestrants

Bile acid sequestrants: mechanisms of action on bile acid and cholesterol metabolism

1991 ◽  
Vol 40 (S1) ◽  
pp. S53-S58 ◽  
Author(s):  
K. Einarsson ◽  
S. Ericsson ◽  
S. Ewerth ◽  
E. Reihnér ◽  
M. Rudling ◽  
...  
Keyword(s):  
Bile Acid ◽  
Cholesterol Metabolism ◽  
Mechanisms Of Action ◽  
Bile Acid Sequestrants

scholarly journals Liver Bile Acid Changes in Mouse Models of Alzheimer’s Disease

2021 ◽  
Vol 22 (14) ◽  
pp. 7451
Author(s):  
Harpreet Kaur ◽  
Drew Seeger ◽  
Svetlana Golovko ◽  
Mikhail Golovko ◽  
Colin Kelly Combs
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Bile Acid ◽  
Bile Acids ◽  
Cholesterol Metabolism ◽  
Amyloid Β ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Liver Cholesterol ◽  
Bile Acid Metabolism

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment. It is hypothesized to develop due to the dysfunction of two major proteins, amyloid-β (Aβ) and microtubule-associated protein, tau. Evidence supports the involvement of cholesterol changes in both the generation and deposition of Aβ. This study was performed to better understand the role of liver cholesterol and bile acid metabolism in the pathophysiology of AD. We used male and female wild-type control (C57BL/6J) mice to compare to two well-characterized amyloidosis models of AD, APP/PS1, and AppNL-G-F. Both conjugated and unconjugated primary and secondary bile acids were quantified using UPLC-MS/MS from livers of control and AD mice. We also measured cholesterol and its metabolites and identified changes in levels of proteins associated with bile acid synthesis and signaling. We observed sex differences in liver cholesterol levels accompanied by differences in levels of synthesis intermediates and conjugated and unconjugated liver primary bile acids in both APP/PS1 and AppNL-G-F mice when compared to controls. Our data revealed fundamental deficiencies in cholesterol metabolism and bile acid synthesis in the livers of two different AD mouse lines. These findings strengthen the involvement of liver metabolism in the pathophysiology of AD.

scholarly journals Role of Baicalin and Liver X Receptor Alpha in the Formation of Cholesterol Gallstones in Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Geng Chen ◽  
Shuodong Wu
Keyword(s):  
Oxidative Stress ◽  
Bile Acid ◽  
Cholesterol Metabolism ◽  
Density Lipoprotein ◽  
Liver X Receptor ◽  
Cholesterol Gallstones ◽  
Receptor Alpha ◽  
Lithogenic Diet ◽  
Liver X Receptor Alpha ◽  
And Oxidative Stress

This study was aimed at investigating the effect of baicalin on experimental cholesterol gallstones in mice. The mouse gallstone model was induced by feeding with a lithogenic diet, and cholesterol stones were found in the gallbladder. The lithogenic diet caused elevation of triglycerides, cholesterol, and low-density lipoprotein concentrations and descent of high-density lipoprotein concentration in serum. Hyperplasia and inflammatory infiltration were observed in the gallbladder wall of lithogenic diet-fed mice. We also found the increase of cholesterol content and the decrease of bile acid in bile. Real-time PCR and western blot results demonstrated that the expression levels of two enzymes (cholesterol 7α-hydroxylase (CYP7a1) and sterol 12α-hydroxylase (CYP8b1)) to catalyze the synthesis of bile acid from cholesterol were decreased and that two cholesterol transporters (ATP-binding cassette transporter G5/G8 (ABCG5/8)) were increased in the liver of lithogenic diet-fed mice. The lithogenic diet also led to enhanced activity of alanine aminotransferase and aspartate aminotransferase in serum; increased concentrations of tumor necrosis factor-α, interleukin- (IL-) 1β, IL-6, and malondialdehyde; and decreased superoxide dismutase activity in the liver, suggesting inflammatory and oxidative stress. In addition, liver X receptor alpha (LXRα) was increased in the liver. After gavage of baicalin, the lithogenic diet-induced gallstones, hyperlipidemia, gallbladder hyperplasia, inflammation, and oxidative stress in liver and cholesterol metabolism disorders were all alleviated to some degree. The expression of LXRα in the liver was inhibited by baicalin. In addition, the LXRα agonist T0901317 aggravated lithogenic diet-induced harmful symptoms in mice, including the increase of gallstone formation, hyperlipidemia, hepatic injury, inflammation, and oxidative stress. In conclusion, we demonstrated that baicalin played a protective role in a lithogenic diet-induced gallstone mouse model, which may be mediated by inhibition of LXRα activity. These findings may provide novel insights for prevention and therapy of gallstones in the clinic.

scholarly journals Role of Bile Acids in the Regulation of Food Intake, and Their Dysregulation in Metabolic Disease

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1104
Author(s):  
Cong Xie ◽  
Weikun Huang ◽  
Richard L. Young ◽  
Karen L. Jones ◽  
Michael Horowitz ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Peptide Yy ◽  
Glycogen Synthesis ◽  
Hormone Secretion ◽  
Gastrointestinal Hormones ◽  
Farnesoid X Receptor ◽  
Gastrointestinal Hormone ◽  
Bile Acid Sequestrants

Bile acids are cholesterol-derived metabolites with a well-established role in the digestion and absorption of dietary fat. More recently, the discovery of bile acids as natural ligands for the nuclear farnesoid X receptor (FXR) and membrane Takeda G-protein-coupled receptor 5 (TGR5), and the recognition of the effects of FXR and TGR5 signaling have led to a paradigm shift in knowledge regarding bile acid physiology and metabolic health. Bile acids are now recognized as signaling molecules that orchestrate blood glucose, lipid and energy metabolism. Changes in FXR and/or TGR5 signaling modulates the secretion of gastrointestinal hormones including glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), hepatic gluconeogenesis, glycogen synthesis, energy expenditure, and the composition of the gut microbiome. These effects may contribute to the metabolic benefits of bile acid sequestrants, metformin, and bariatric surgery. This review focuses on the role of bile acids in energy intake and body weight, particularly their effects on gastrointestinal hormone secretion, the changes in obesity and T2D, and their potential relevance to the management of metabolic disorders.

scholarly journals Lactobacillus delbrueckii Interfere With Bile Acid Enterohepatic Circulation to Regulate Cholesterol Metabolism of Growing–Finishing Pigs via Its Bile Salt Hydrolase Activity

2020 ◽  
Vol 7 ◽  
Author(s):  
Gaifeng Hou ◽  
Wei Peng ◽  
Liangkai Wei ◽  
Rui Li ◽  
Yong Yuan ◽  
...  
Keyword(s):  
Bile Acid ◽  
Enterohepatic Circulation ◽  
Cholesterol Metabolism ◽  
Binding Protein ◽  
Density Lipoprotein ◽  
Lactobacillus Delbrueckii ◽  
Farnesoid X Receptor ◽  
Bile Salt Hydrolase ◽  
Lipoprotein Receptor ◽  
Density Lipoprotein Receptor

Microbiota-targeted therapies for hypercholesterolemia get more and more attention and are recognized as an effective strategy for preventing and treating cardiovascular disease. The experiment was conducted to investigate the cholesterol-lowering mechanism of Lactobacillus delbrueckii in a pig model. Twelve barrows (38.70 ± 5.33 kg) were randomly allocated to two groups and fed corn–soybean meal diets with either 0% (Con) or 0.1% Lactobacillus delbrueckii (Con + LD) for 28 days. L. delbrueckii–fed pigs had lower serum contents of total cholesterol (TC), total bile acids (TBAs), and triglyceride, but higher fecal TC and TBA excretion. L. delbrueckii treatment increased ileal Lactobacillus abundance and bile acid (BA) deconjugation and affected serum and hepatic BA composition. Dietary L. delbrueckii downregulated the gene expression of ileal apical sodium-dependent bile acid transporter (ASBT) and ileal bile acid binding protein (IBABP), and hepatic farnesoid X receptor (FXR), fibroblast growth factor (FGF19), and small heterodimer partner (SHP), but upregulated hepatic high-density lipoprotein receptor (HDLR), low-density lipoprotein receptor (LDLR), sterol regulatory element binding protein-2 (SREBP-2), and cholesterol-7α hydroxylase (CYP7A1) expression. Our results provided in vivo evidence that L. delbrueckii promote ileal BA deconjugation with subsequent fecal TC and TBA extraction by modifying ileal microbiota composition and induce hepatic BA neosynthesis via regulating gut–liver FXR–FGF19 axis.

scholarly journals Short- and long-term effects of biliary drainage on hepatic cholesterol metabolism in the rat

1990 ◽  
Vol 269 (3) ◽  
pp. 781-788 ◽  
Author(s):  
M J Smit ◽  
A M Temmerman ◽  
R Havinga ◽  
F Kuipers ◽  
R J Vonk
Keyword(s):  
Bile Acid ◽  
Bile Flow ◽  
Cholesterol Metabolism ◽  
Acid Output ◽  
Biliary Secretion ◽  
Surgical Trauma ◽  
Hepatic Cholesterol ◽  
Long Term Effects ◽  
Short And Long Term

The present study concerns short- and long-term effects of interruption of the enterohepatic circulation (EHC) on hepatic cholesterol metabolism and biliary secretion in rats. For this purpose, we employed a technique that allows reversible interruption of the EHC, during normal feeding conditions, and excludes effects of anaesthesia and surgical trauma. [3H]Cholesteryl oleate-labelled human low-density lipoprotein (LDL) was injected intravenously in rats with (1) chronically (8 days) interrupted EHC, (2) interrupted EHC at the time of LDL injection and (3) intact EHC. During the first 3 h after interruption of the EHC, bile flow decreased to 50% and biliary bile acid, phospholipid and cholesterol secretion to 5%, 11% and 19% of their initial values respectively. After 8 days of bile diversion, biliary cholesterol output and bile flow were at that same level, but bile acid output was increased 2-3-fold and phospholipid output was about 2 times lower. The total amount of cholesterol in the liver decreased after interruption of the EHC, which was mainly due to a decrease in the amount of cholesteryl ester. Plasma disappearance of LDL was not affected by interruption of the EHC. Biliary secretion of LDL-derived radioactivity occurred 2-4 times faster in chronically interrupted rats as compared with the excretion immediately after interruption of the EHC. Radioactivity was mainly in the form of bile acids under both conditions. This study demonstrates the very rapid changes that occur in cholesterol metabolism and biliary lipid composition after interruption of the EHC. These changes must be taken into account in studies concerning hepatic metabolism of lipoprotein cholesterol and subsequent secretion into bile.

scholarly journals Regulation of Bile Acid and Cholesterol Metabolism by PPARs

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Tiangang Li ◽  
John Y. L. Chiang
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Cholesterol Metabolism ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Cholesterol Homeostasis ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Major Pathway ◽  
Therapeutic Implications

Bile acids are amphipathic molecules synthesized from cholesterol in the liver. Bile acid synthesis is a major pathway for hepatic cholesterol catabolism. Bile acid synthesis generates bile flow which is important for biliary secretion of free cholesterol, endogenous metabolites, and xenobiotics. Bile acids are biological detergents that facilitate intestinal absorption of lipids and fat-soluble vitamins. Recent studies suggest that bile acids are important metabolic regulators of lipid, glucose, and energy homeostasis. Agonists of peroxisome proliferator-activated receptors (PPARα, PPARγ, PPARδ) regulate lipoprotein metabolism, fatty acid oxidation, glucose homeostasis and inflammation, and therefore are used as anti-diabetic drugs for treatment of dyslipidemia and insulin insistence. Recent studies have shown that activation of PPARαalters bile acid synthesis, conjugation, and transport, and also cholesterol synthesis, absorption and reverse cholesterol transport. This review will focus on the roles of PPARs in the regulation of pathways in bile acid and cholesterol homeostasis, and the therapeutic implications of using PPAR agonists for the treatment of metabolic syndrome.

Abstract 329: HSF-1 Knockout Enhances Dietary Cholesterol Metabolism by Inducing CYP7A1 Gene Expression and Attenuates Atherosclerosis

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Govindasamy Ilangovan ◽  
Krishnamurthy Karthikeyan
Keyword(s):  
Heart Disease ◽  
Bile Acid ◽  
Heat Shock ◽  
Cholesterol Metabolism ◽  
Dietary Cholesterol ◽  
Atherosclerotic Lesion ◽  
Heat Shock Factor 1 ◽  
Mrna Levels ◽  
Gene Promoters ◽  
Gene Expressions

Objective: Coronary heart disease and diabetes are highly prevalent among obese populations due to aberrant dietary cholesterol metabolism. Here we investigated the effect of heat shock factor-1 (HSF-1) on atherosclerosis and dietary cholesterol metabolism. Methods and Results: Atherogenic western diet-induced weight gain was reduced in HSF-1 and LDLr double knock out mice (HSF-1 -/- /LDLr -/- ), compared to LDLr -/- mice. Atherosclerotic lesion growth in aortic arch and carotid regions was retarded. Also, repression of PPAR-γ2 and AMPKα expression in adipose tissue, low hepatic steatosis, and lessened plasma adiponectins and lipoproteins were observed. Furthermore, reduced heat shock proteins and their mRNA levels in atherosclerotic lesions correlated with reduction in lesion burden. In HSF-1 -/- /LDLr -/- liver, higher cholesterol 7α hydroxylase (CYP7A1, the rate limiting enzyme in the synthesis of bile acid from cholesterol) and MDR1/p-glycoprotein (bile salt transporter across the hepatocyte canalicular membrane) gene expressions were observed, consistent with higher bile acid sequestration and larger hepatic bile ducts. HSF-1 deletion, however, upregulated both CYP7A1 enzyme and MDR1/p-glycoportein expression and activities, due to removal of its repressive binding in the CYP7A1 and MDR1 gene promoters. This increased the conversion of cholesterol into 7-α-hydroxycholesterol and bile acid, and dietary cholesterol metabolism. Conclusions: HSF-1 ablation not only eliminates heat shock response to retard atherosclerosis, but it also transcriptionally upregulates CYP7A1 and MDR1/P-gp axis to increase cholesterol metabolism. Therefore, HSF-1 is a metabolic regulator of dietary cholesterol and a major contributor to heart disease among obese population.

Abstract 49: The Transcriptional Repressor MafG Regulates Cholesterol Catabolism

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Thomas Q de Aguiar Vallim ◽  
Elizabeth J Tarling ◽  
Hannah Ahn ◽  
Lee R Hagey ◽  
Casey E Romanoski ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Acid Metabolism ◽  
Metabolic Diseases ◽  
Cholesterol Metabolism ◽  
Transcriptional Repressor ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Bile Acid Metabolism ◽  
Biliary Bile Acid

Elevated circulating cholesterol levels is a major risk factor for cardiovascular diseases (CVD), and therefore understanding pathways that affect cholesterol metabolism are important for potential treatment of CVD. The major route for cholesterol excretion is through its catabolism to bile acids. Specific bile acids are also potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis ( Cyp7a1 , Cyp8b1 ) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway, and modifies the biliary bile acid composition. In contrast, MafG loss-of-function studies cause de-repression of the bile acid genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-Seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR. The identification of this pathway will likely have important implications in metabolic diseases.

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