[Ursodeoxycholic acid: history and clinical implications]

The physiologic bile acid ursodeoxycholic acid (UDCA) has potent anticholestatic and weak litholytic properties and has been used for centuries as a remedy for cholestatic liver diseases. Today, UDCA at 13-15 mg/kg/day is the standard first line medication for all people with primary biliary cholangitis (PBC), the most frequent chronic cholestatic liver disease where UDCA clearly improves long-term survival. For many other chronic cholestatic conditions, anticholestatic effects are described, but long-term data are incomplete. While UDCA's litholytic properties can be explained by lowering biliary cholesterol hypersaturation, its beneficial effects in cholestatic diseases build on different mechanisms of action, namely: (i) stimulation of hepatobiliary secretion by post-transcriptional mechanisms including membrane targeting and insertion of key transporters and ion channels, (ii) stabilization of a biliary bicarbonate umbrella by stimulation of biliary chloride/bicarbonate secretion, and (iii) inhibition of hepatocyte and cholangiocyte apoptosis and reduction of endoplasmic reticulum stress induced by toxic endogenous bile acids.