Human Mesenchymal Stem Cells Injected Via Portal Vein Are Differentiated into Human Hepatocytes in Regenerating Rat Liver.

Objectives: Human mesenchymal stem cells (MSCs) possess versatile differentiation potential ranging from mesenchyme-related multipotency to neuroectodermal and endodermal competency. Evidence has been accumulated to indicate that certain compartments of bone marrow cells are capable to differentiating into hepatocytes in vitro. In this study we attempted to examine the differentiation ability of human MSCs into hepatocytes in vitro and in vivo by injected them into rat portal vein in partially resected rat liver model.

Materials and Methods: MSCs were isolated from human bone marrow and induced differentiation with our protocol containing hepatocyte growth factor in vitro. Four - to - 5 week-old female Sprague Dawley rats were used for xenotransplantation model. Culture expanded MSCs (5 X 10⁶ cells/rat) were injected into the portal vein and 70% hepatectomy was performed on the subsequent day. All rats were immunosuppressed with a daily intraperitoneal injection of cyclosporine A.

Results: The morphology of the MSCs was changed into hepatocyte-like cells after in vitro culture for 28days and expression of hepatocyte specific genes also confirmed with RT-PCR and immunohistochemical stain. Transplanted MSCs differentiated into hepatocytes and they surprisingly composed hepatic cords with expression of the human albumin and human hepatocyte specific genes at 21 days after infusion.

Conclusion: We have demonstrated that human MSCs can differentiate into functional hepatocyte-like cells in vitro and in vivo. Therefore, human MSCs may become an alternative source to hepatocyte regeneration or liver cell transplantation.