Hepatocyte and mesenchymal stem cell co-transplantation in rats with acute liver failure.

Background: Cell therapy is considered a potential alternative to liver transplantation in acute liver failure (ALF). We aimed to evaluate the add-on therapeutic benefit of hepatocyte and mesenchymal stem cell (MSC) cotransplantation over hepatocyte-only transplantations in a rat model of ALF. Methods: ALF was induced by D-galactosamine in Sprague-Dawley rats. Freshly isolated donor hepatocytes were derived from Tg (UBC-emGFP) rats and MSCs were collected from the bone marrow cells of DsRed rats. Donor hepatocytes (1×107/mL) were intraportally transplanted 24 hours after treatment with D-galactosamine over a 70-second interval, and donor MSCs (0.5, 1, or 2×106/0.5 mL) were intraportally transplanted 1 hour after the hepatocyte transplantation was complete. Animals were sacrificed after 7 and 14 days and subjected to donor cell identification, liver histology, serologic testing, and immunohistopathological examination. Results: MSCs were observed in the periportal area, 1 and 2 weeks after transplantation. Transplanted hepatocytes did not actively proliferate when compared to hepatocyte-only transplantation. Morphologically, transplanted MSCs did not appear to differentiate into hepatocytes even 2 weeks after transplantation. Cotransplantation of MSCs was associated with lower macrophage infiltration, and reduced type I collagen, hepatocyte growth factor, tumor necrosis factor-α, and interleukin 10 expression, with similar gene expression profiles for epidermal growth factor and interleukin 6, when compared to hepatocyte-only transplantation. Conclusions: Hepatocyte and MSC cotransplantation is feasible and safe in rat models of ALF. MSCs were found to survive the process and could be located within the periportal niches 2 weeks after treatment, without enhancing transplanted hepatocyte proliferation or differentiating into hepatocytes, while ameliorating the inflammatory response.