Tolerance might be stably induced by both mesenchymal stem cell and hepatocyte growth factor in heart transplantation

Heart transplantation still remains the best choice of treatment for many kinds of end-stage heart diseases, but the side-effects of immunosuppressive agents and cardiac allograft vasculopathy (CAV) remain the main two obstacles in improving the long outcome of cardiac allografts. Mesenchymal stem cells (MSCs) are nonhematopoietic pluripotent cells that retain the ability to undergo differentiation into cells of different lineages. What's more, MSCs have been demonstrated to exert many profound inhibitory effects on many lymphocytic subpopulations such as T cells, regulatory T cells, and dendritic cells in vitro. In vivo studies also suggested that MSCs could be used to attenuate immune-mediated disorders such as transplant rejection and autoimmune diseases including rheumatoid arthritis, multiple sclerosis and GVHD. Hepatocyte growth factor (HGF) is a pleiotropic factor that plays an important role in protecting infarcted myocardial by its antiapoptotic, antifibrotic and angiogenic effects. And also it was suggested that the administration of HGF could effectively suppress acute and chronic cardiac allograft rejection. We based our hypothesis on that HGF-modified MSCs would engraft stably in recipient and interact with important immune cells such as T cells, B cells and dendritic cells, then stable immune tolerance be induced possibly by both immunomodulation of MSCs and cardioprotective and immunomodulative effects of HGF. Further work is necessary to highlight the specific underlying mechanisms.