Impact of adipose tissue or umbilical cord derived mesenchymal stem cells on the immunogenicity of human cord blood derived endothelial progenitor cells.

The application of autologous endothelial progenitor cell (EPC) transplantation is a promising approach in therapeutic cardiovascular diseases and ischemic diseases. In this study, we compared the immunogenicity of EPCs, adipose tissue (AD)-derived mesenchymal stem cells (MSCs) and umbilical cord (UC)-derived MSCs by flow cytometry and the mixed lymphocyte reaction. The impact of AD-MSCs and UC-MSCs on the immunogenicity of EPCs was analyzed by the mixed lymphocyte reaction and cytokine secretion in vitro and was further tested by allogenic peripheral blood mononuclear cell (PBMC) induced immuno-rejection on a cell/matrigel graft in an SCID mouse model. EPCs and AD-MSCs express higher levels of MHC class I than UC-MSCs. All three kinds of cells are negative for MHC class II. UC-MSCs also express lower levels of IFN-γ receptor mRNA when compared with EPCs and AD-MSCs. EPCs can stimulate higher rates of proliferation of lymphocytes than AD-MSCs and UC-MSCs. Furthermore, AD-MSCs and UC-MSCs can modulate immune response and inhibit lymphocyte proliferation induced by EPCs, mainly through inhibition of the proliferation of CD8+ T cells. Compared with UC-MSCs, AD-MSCs can significantly improve vessel formation and maintain the integrity of neovascular structure in an EPC+MSC/matrigel graft in SCID mice, especially under allo-PBMC induced immuno-rejection. In conclusion, our study shows that AD-MSC is a powerful candidate to minimize immunological rejection and improve vessel formation in EPC transplantation treatment.

[Research and clinical applications regarding endothelial progenitor cell transplantation].

Endothelial injury or dysfunction leads to multiple cardiovascular diseases, such as atherosclerosis, myocardial infarction, stroke, hypertension and peripheral vascular disease. Endothelial progenitor cells (EPCs) are precursor cells of endothelial cells, including the early endothelial progenitor cells and the late endothelial progenitor cells. These two EPC types have different function and surface markers. EPC in this article mainly means late endothelial progenitors which could grow into endothelial cloning and form vessels in vivo. Late EPCs can express CD133, CD31, KDR, CD144, CD34 etc, take in low density lipoprotein, bind with ulex europaeus lectin 1 and form blood vessels in vitro and in vivo. EPCs not only participate in new blood vessels formation, but also are closely related to the repair of damaged endothelium. Many studies confirm that the transplanted EPCs are able to be mobilized to vascular injury location and repair the damaged endothelial cells thus promote new blood vessel formation, which provides a promising strategy for the treatment of cardiovascular diseases and ischemic diseases.