A review of bile acid sequestrants: potential mechanism(s) for glucose-lowering effects in type 2 diabetes mellitus.
ABSTRACT Clinical evidence has demonstrated that bile acid sequestrants reduce glucose levels in patients with type 2 diabetes mellitus (T2DM). This effect has been confirmed in multiple double-blind, placebo-controlled clinical studies with the bile acid sequestrant colesevelam hydrochloride (HCl). Colesevelam HCl was approved by the US Food and Drug Administration in January 2008 as an adjunctive therapy for patients with T2DM to improve glycemic control. However, the mechanism of action for the glucose-lowering effect of bile acid sequestrants is unclear. Bile acid sequestrants are nonsystemic pharmacological agents that bind bile acids in the gastrointestinal tract, thereby diverting bile acids from the enterohepatic circulation. This, in turn, upregulates bile acid synthesis (via cholesterol 7-alpha-hydroxylase), which utilizes cholesterol, resulting in reduced low-density lipoprotein cholesterol levels. Recent research has revealed that bile acids are tightly controlled signaling molecules that have metabolic effects beyond their primary role in bile to aid in the digestion of lipids and fat. Bile acids signal via various membrane and nuclear receptors. Therefore, bile acid sequestrants may exert glycemic effects by altering the interaction of these bile acid pathways. This article reviews the role for bile acids in glucose regulation and discusses the potential mechanism(s) of action for the glycemic effects of bile acid sequestrants.
- SourceAvailable from: John Y L Chiang
Dataset: #123.Bile acid metabolism MolPatho
Article: Bile Acid metabolism and signaling.[Show abstract] [Hide abstract]
ABSTRACT: Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans. © 2013 American Physiological Society. Compr Physiol 3:1191-1212, 2013.Comprehensive Physiology. 07/2013; 3(3):1191-212.