[Human cord blood adult stem cells differentiate into hepatocyte-like cells in vitro]

Abstract

The aim of this study was to investigate the feasibility of the human cord blood adult stem cells (ASCs) to differentiate into hepatocytes in vitro induced by combined stimulation with hepatocyte growth factor (HGF), stem cell factor (SCF) and leukemia inhibitory factor (LIF). The adult stem cells were obtained through density gradient centrifugation and magnetic activated cell sorting (MACS). The adult stem cells were cultured in DMEM with HGF (10 ng/ml)+SCF (10 ng/ml)+LIF (10 ng/ml) in induced group I. In induced group II the enriched cells were cultured in DMEM with SCF (10 ng/ml)+LIF (10 ng/ml) and the undifferentiated cells acted as the control group without the factors. The morphology of cells was observed by the inverted phase contrast microscopy; the expression of albumin (Alb), human hepatocyte cytokeratin (CK18) and alpha-fetoprotein (AFP) were detected by immunofluorescence, immunohistochemistry and RT-PCR assay in the 21-day culture. Alb secreted by hepatocytes in the medium was determined by radioimmunoassay (RIA) at day 7, 14, 21, 23 and 25. The results showed that the shapes of ASCs changed and their sizes and number increased in the course of culture in group I. After being induced for three weeks, the cells turned round and resembled hepatocyte-like cells. The mRNA for Alb could be detected by RT-PCR in the differentiated adult stem cells in group I, and the mRNA for AFP was poorly detected by RT-PCR at day 21. Alb and CK18 were positive through immunofluorescence and immunohistochemistry at day 21, compared with group II and the control group. In group I, Alb in the medium significantly increased, compared with control group, and reached the highest level at day 21, then decreased at day 23. It is concluded that under some definite inducing conditions, human cord blood adult stem cells can differentiate into hepatocyte-like cells and HGF plays a critical role during the course.