Our lab has isolated multipotent adult progenitor cells, or MAPC, rare cells within human mesenchymal stem cell cultures generated from human and rodent bone marrow or other tissues. MAPCs are capable of differentiating in vitro to cells of the three germ layers. In addition, MAPC differentiate into cells with morphological, phenotypic, and functional characteristics of hepatocytes in vitro. We hypothesize that transplantation of undifferentiated MAPC or MAPC induced to differentiate to hepatocyte-like differentiated cells will engraft into the native liver and contribute to functional regeneration. Using a retrorsine - partial hepatectomy model we will evaluate whether MAPC and hepatocyte-like differentiated MAPCs are able to engraft into native liver. Evaluation of engraftment will be done using FISH, RT-PCR, cell luminescence, and direct liver mass measurements. Fusion of transplanted cells to native cells will be evaluated with a method involving Cre/Lox recombination.