Bile acids and Cholesterol

Bile acids and cholesterol are critical lipid molecules that serve as structural components, metabolic precursors, and signaling agents within the human body. Cholesterol is a vital constituent of cell membranes, maintaining fluidity and permeability, and serves as the primary substrate for the synthesis of steroid hormones, vitamin D, and bile acids (StatPearls: Physiology, Cholesterol, 2023). Bile acids are synthesized in the liver from cholesterol and are secreted into the bile to facilitate the emulsification and absorption of dietary fats and fat-soluble vitamins in the small intestine (PubMed: PMC4945903). Beyond their digestive roles, bile acids function as endocrine signaling molecules by activating the Farnesoid X Receptor (FXR) and the G protein-coupled bile acid receptor (TGR5), which regulate glucose, lipid, and energy metabolism (Nature Reviews Drug Discovery, 2020). Dysregulation of these pathways is a major driver of cardiovascular disease, particularly through the development of atherosclerosis, as well as liver diseases like cholestasis and nonalcoholic steatohepatitis (NASH) (NIH: LiverTox, 2020). Pharmacological strategies include lowering circulating cholesterol levels via statins or ezetimibe and modulating bile acid pools or signaling to treat metabolic and biliary disorders (StatPearls: Lipid Lowering Drugs, 2023).

Other names

Bile saltsSterolsCholesterol metabolitesPrimary and secondary bile acids

Drugs targeting these pathways work by inhibiting endogenous cholesterol synthesis (HMG-CoA reductase inhibitors), preventing intestinal absorption of cholesterol (NPC1L1 inhibitors), sequestering bile acids in the gut to promote their excretion, or activating nuclear and membrane receptors (FXR and TGR5) to regulate metabolic homeostasis.