Immature Biliary Epithelial Cells (IHBT)

Immature biliary epithelial cells (BEC) line the lumen of the intrahepatic bile ducts (IHBD) and arise from hepatoblasts in contact with the portal vein. These hepatoblasts form a monolayer, and then a bi-layer, of cuboidal biliary precursors that demonstrate increased cytokeratin-19 expression and downregulation of hepatic genes. 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 apoptose.