Cholangiocyte biology

Purpose of review: Cholangiocytes are increasingly recognized as biologically important because of the diversity of cellular processes in which they participate. Collectively, these processes define normal function and, when disturbed, account for abnormalities that cause disease. Advances in animal models of disease, sophistication of technology in imaging, and gene silencing have allowed progress in defining the roles that cholangiocytes play in signaling; transport of water, ions, and solutes; and alterations that result in cholestasis. The pace of advances in technology justifies a yearly summary to identify the most important developments in cholangiocyte biology. Recent findings: The main areas of recent progress include insights into the molecular mechanisms of hormone-induced bile secretion, development of new experimental models, and a better understanding of the mechanisms of cholestasis. Summary: Understanding the normal components and key biologic processes in cholangiocytes responsible for the regulation of ductal bile secretion is an initial and required step in generating hypotheses relevant to disease. With regard to the pathologic relevance of this work, cholestatic liver diseases represent a broad group of hepatobiliary disorders with which hepatologists must deal. In addition to genetic defects, the study of the normal and altered trafficking of cholangiocyte transport systems involved in bile secretion may provide a molecular correlate for the functional changes that occur in cholestasis. Crucial to this understanding is the ongoing development of experimental models and techniques to answer key hypothesis-driven questions. Additionally, the collegial sharing and exchange of novel concepts, ideas, reagents, and probes promotes positive advances in the field.