Evaluation of porcine mesenchymal stem cells for therapeutic use in human liver cancer.

Mesenchymal stem cell (MSC) transplantation is suggested for therapy of end-stage liver disease, due to e.g. liver cancer and metastasis. Liver transplantation is the only therapeutic option so far but donor organs are short. Also, the availability of allogeneic human MSCs for liver regeneration is limited. Therefore, we evaluated the suitability of porcine bone marrow MSCs from semi-adult pigs and found that morphology, surface expression pattern and multilineage differentiation are similar to those of human MSCs. Porcine MSCs differentiated to a hepatocyte-like phenotype and expressed porcine mRNA of typical liver proteins. However, hepatocyte-like MSCs failed to express the corresponding proteins and did not produce glycogen and urea as primary porcine hepatocytes do. Porcine MSCs were immunotolerated, since they did not activate resting human PBMCs, and were not attacked by human activated PBMCs. However, porcine MSCs led to enhanced proliferation of human pre-activated PBMCs suggesting that immunotoleration of porcine MSCs in the human system has limitations. Together, the potential of porcine MSCs for xenogenous use in human liver therapy is promising but needs further evaluation prior to clinical use.