ABCB4 and hepatic granuloma: In areas of hepatic granulomas, where pre-existing bile ducts may be compressed, choleretic UDCA could provoke a local aggravation of the biliary reaction, as observed under more pronounced cholestatic conditions (e.g., Abcb4/Mdr2−/− mice and bile duct ligation), by enhancing biliary pressure and subsequent bile infarcts while norUDCA was beneficial [22], [23].