Fig. 2: Bile acid circulation and bile reflux.
From: Roles and action mechanisms of bile acid-induced gastric intestinal metaplasia: a review
Primary bile acids (e.g., CA and CDCA) are synthesized by cholesterol mediated. They conjugated with glycine or taurine (G/T), and stored in the gallbladder. The majority (90–95%) of bile acid secreted into the small intestine are reabsorbed in the terminal ileum through portal vein and circulate back to the liver. Gut microbiota contributes to the conversion of CA and CDCA into secondary bile acids through dehydroxylation (e.g., DCA and LCA), which are mostly excreted from feces (5–10% of bile acid). Bile reflux to the stomach can induce mucosal dysfunction through some factors, such as dissolution of the phospholipid layer, low pH, mastocyte-secreting histamine, gastric antrum G-cell-secreting gastrin, microbiota disorder, and changes of the miRNA profile.
