Presence of markers for liver progenitor cells in human-derived intrahepatic biliary epithelial cells.

AIMS: Rodent intrahepatic bile duct may harbor bipotential liver progenitor cells. In this study, human-derived intrahepatic biliary epithelial cells (BECs) were investigated in terms of whether they have the character of liver progenitor cells.

METHODS: Ten liver tissue specimens were obtained after partial hepatectomy or liver explantation. Intrahepatic BECs were isolated by density-gradient centrifugation and immunomagnetic separation using anti-human epithelial antigen and cultured in medium containing epidermal growth factor and hepatocyte growth factor. The isolated and cultured cells were characterized by immunostaining and reverse transcription polymerase chain reaction with a variety of markers for fetal hepatocytes and liver progenitor cells.

RESULTS: These cells had proliferated for up to 18 weeks in vitro. They continuously expressed epithelial markers (cytokeratin (CK) 8 and CK 18) as well as biliary markers (CK 7 and CK 19). Remarkably, some isolated and cultured cells also expressed markers for fetal hepatocytes and liver progenitor cells, including albumin, alpha-fetoprotein, alpha1-antitrypsin, c-kit and chromogranin-A.

CONCLUSION: Some human-derived intrahepatic BECs coexpressed markers for liver progenitor cells. This finding further supports the hypothesis that the human biliary tree may also consist of liver progenitor cells.