Pathobiology of biliary epithelia

Recently, principally owing to the development of suitable experimental models, significant advances have been made in our understanding of the biological and pathobiological importance of intrahepatic biliary epithelial cells, or cholangiocytes. These advances include 1) the development of techniques to isolate and culture rodent and human cholangiocytes; 2) an appreciation of the mechanisms by which cholangiocytes contribute to bile formation via hormone-stimulated secretion of ions and water; and 3) a recognition that cholangiocytes are candidate target cells in several important chronic liver diseases. In this review, we first discuss the experimental models recently developed to study biliary epithelia then detail current concepts on the cellular mechanisms of hormone-induced ductal bile secretion. We then briefly summarize selected information on the pathophysiology of bile duct injury, emphasizing those liver diseases in which cholangiocytes appear to be the principal targets for immune-mediated destruction.