Hepatic potential of bone marrow stromal cells: development of in vitro co-culture and intra-portal transplantation models.

Bone marrow comprises heterogeneous cell populations and is thought to contain certain progenitors with the ability to differentiate into multiple mesenchymal cell lineages. To identify any differentiation plasticity of adult bone marrow stromal cells (BMSCs) into hepatocyte-like phenotypes, we developed a co-culture model with damaged liver tissue and an animal model of engraftment in cirrhotic liver via intra-portal transplantation. After 10 days of co-culture with injured liver tissues, BMSC expressed specific markers for hepatocytes by RT-PCR and Western blot. The two animal models for liver injury employed used carbon tetrachloride (CCl4) induction or bile duct ligation. For tracing BMSC resident in the liver after intra-portal transplantation, green fluorescent protein (GFP)-positive BMSCs or in situ hybridization of Y-chromosome Sry gene in male BMSC were used in a cross-sex transplantation model. Expression of hepatocyte-specific markers in recipients' liver tissues was determined by fluorescence immunohistochemistry. Our findings demonstrated that about 16% parenchyma cells were GFP-positive cells derived from infused BMSCs, and expression of albumin was detected in these cells in engrafted liver tissues. In conclusion, BMSCs exhibited hepatocyte-like phenotypes after co-cultivation with liver tissue and transplanted into the injured liver. The presented evidence indicated the trans differentiation potential of BMSC developing to the hepatocytes.

Expression of hepatocyte-like phenotypes in bone marrow stromal cells after HGF induction.

Bone marrow comprises heterogeneous cell populations, of which certain progenitors have demonstrated the ability to differentiate into multiple mesenchymal cell lineages. This study demonstrates the bone marrow stromal cells (BMSCs) with intrinsic plasticity to differentiate into hepatocyte-like phenotypes under in vitro induction of hepatocyte growth factor (HGF). BMSCs isolated from rat femurs and tibias were cultured and passaged 3-4 times in the presence of HGF. Cells were harvested on days 0, 10, and 20 and subjected to examination of any hepatocyte characteristics by flow cytometry, RT-PCR, Western blot, and immunocytochemistry. Expression of albumin and alpha-fetoprotein at both mRNA and protein levels was detectable on day 10. By contrast, c-Met mRNA was significantly decreased in BMSC in the course of HGF induction. Here BMSC was shown to differentiate into hepatocyte-like phenotypes given the HGF induction, as an alternative source for adult stem cell transplantation in liver repair.