Methods: CD117+ fraction was magnetically separated from human exfoliated deciduous teeth (SHED) cell cultures established previously. Serum-free DMEM supplemented with ITS-x, embryo-trophic factors and hepatocyte growth factor for 5 days; and oncostatin and dexamethasone were added to the culture medium for another15 days to induce hepatic differentiation. Human hepatically-specific markers were examined after differentiation by immunofluorescence. Urea concentrations in culture media were measured by ELISA. Glycogen was visualized by PAS staining. Twelve F344-nude rats were subjected to 90% liver resection. Hepatically differentiated cells were transplanted in the spleens (1× 107 cells /animal) of six of the animals. The livers and spleens were collected 40 days after the transplantation. The hepatic markers in the liver were tested by immunohistochemistry. Expression of human albumin in rats’ livers was proven by in situhybridization. Concentrations of human albumin, α-feto-protein (aFP) and IGF-1 in serum were determined.
Results: After in vitrohepatic differentiation almost 100% of cells were deemed as hepatic-like; aFP, albumin, IGF-1 and HNF4-α were all shown to be positive by immunofluorescence. The concentration of urea in the media increased (p<0.05). Cell clusters expressing human-specific hepatic markers were found in the rats’ livers and spleens by immunofluorescence. Human specific albumin, aFP and IGF-1 were found in rats’ serum.
Conclusions: Hepatocyte-like cells differentiated in vitro were transplanted into the rats and they functioned as human hepatocytes. SHED may therefore be ideal cell source for cell-based therapy of patients requiring liver transplantation.