In Vitro Systems for the Study of the Intrahepatic Biliary Epithelium
The intrahepatic biliary epithelium is a simple epithelium that until relatively recently was thought to function solely as an inert lining to the biliary ductular system. Improved methods to allow adequate purification and maintenance of viable intrahepatic biliary epithelial cells (IBEC) for culture, have permitted demonstration of functional specializations of IBEC concerned with modulation of the lumenal content of biliary ducts (bile), and immunological protection of the internal environment. With the development of reproducible techniques to enable the isolation of IBEC with high purity and viability, considerable progress has been made in the subsequent development of culture systems for maintaining the cells in vitro. The response of IBEC cultured with 3T3 fibroblasts is consistent with the concept that mesenchymal cells located in the periductal stroma of bile ducts are a source of factors that stimulate proliferation and differentiation of IBEC in vivo.