Isolation and characterization of epithelial progenitor cells from human fetal liver

Aim: Hepatic progenitor cells can serve as an alternative source of hepatocytes for the treatment of liver diseases. Methods: We isolated and expanded the epithelial progenitor cells (EPC) from the human fetal liver and investigated the differentiation of EPC into hepatic cells by fluorescence-activated cell sorter (FACS), real-time polymerase chain reaction (PCR), immunofluorescence assay, western blotting, and periodic acid-Schiff staining. Results: Isolated EPC possessed highly proliferative ability and subpassaged for more than 25 passages. Real-time PCR showed that EPC expressed liver epithelial markers (cytokeratin [CK]8 and CK18) and biliary-specific markers (CK7 and CK19). FACS analysis indicated that these cells were positive for CD117, CD147, CD90, CD44, human leucocyte antigen class I and CD71, but negative for CD34 and CD45. The EPCpossessed multipotential indicated by differentiating into osteoblasts and adipocytes; when subjected to the hepatic differentiation condition, EPC could be induced to hepatocyte-like cells, which expressed albumin, alpha-fetoprotein, and CK18 proteins. Two months after EPC transplantation, we observed that the grafted cells differentiated into hepatocyte-like cells and there was no observable tumor mass. Conclusion: We have isolated and characterized the human fetal liver-derived EPC and these cells may serve as an ideal cell source for cell-replacement therapy of diseased livers.