Role of Bile Acids and Nuclear Receptors in Acupuncture in Improving Crohn’s Disease

Figure 1

Schematic diagram of bile acid synthesis pathway and gut-liver circulation. The synthesis of BAs is mainly through classical and alternative pathways. The classical pathway is initiated by CYP7A1, and the alternative pathway is initiated by CYP27A1. CDCA is synthesized by cholesterol through a series of enzymatic reactions. CDCA forms conjugated CDCA by binding with glycine or taurine and are secreted into the intestine through bile duct. About 95% of BAs is transported into portal vein by intestinal epithelial cells and reabsorbed by hepatocytes and the remaining 5% will be excreted with feces. CYP7A1: cholesterol 7α-hydroxylase; HSD3B7: 3β-hydroxysteroid dehydrogenase; CYP8B1: sterol 12α-hydroxylase; CA: cholic acid; CDCA: chenodeoxycholic acid; CYP7B1: oxysterol 7α-hydroxylase; and CYP27A1: sterol 27-hydroxylase.