Biliary epithelial cells (BEC) line the lumen of the intrahepatic bile ducts (IHBD) and arise from hepatoblasts in contact with the portal vein of the developing liver. This subpopulation of hepatoblasts forms a monolayer, and then a bi-layer, of cuboidal biliary precursors with heightened cytokeratin-19 expression and downregulated hepatic gene expression. Between E17 and into the perinatal period ductal plate remodeling occurs, during which tubulogenesis takes place, as manifested by focal dilations in the bi-layer, which are eventually surrounded by portal mesenchyme to form the IHBD. The remaining bi-layer cells regress.
In human liver, the earliest hepatoblasts express CK8, 18, and 19. When they give rise to cholangiocytes, CK19 expression increases, but is fully absent in hepatocytes. CK8 and 18 expression persists in both cell types. Similarly, CK19 is absent in hepatoblasts and is only detectable in cholangiocytes in mouse and rat liver.
Multiple AncestorsSingle AncestorNo DescendantsDevelops fromPart of Parent