Human skin-derived mesenchymal stem cells as a source of VEGF and nitric oxide

Researches on stem cells bring promise to functional skin repair. In particular, it has been recently suggested that mesenchymal stem cells (MSCs) could positively affect cutaneous wound healing through differentiation and paracrine action. The molecular mechanisms are not clear, even if there is increasing evidence for an important action of nitric oxide (NO), probably mediated by the regulation of the gene encoding for vascular endothelial growth factor (VEGF). The aim of our study was to investigate the immunohistochemical expression of VEGF and nitric oxide synthase (NOS) isoforms in human skin-derived MSCs, as well as the production of VEGF and NO, because these cells are less well characterized than bone marrow MSCs. MSCs were obtained from skin biopsies of healthy adult patients undergoing cosmetic plastic surgery, expanded and characterized for specific surface antigens. The cells were then evaluated for the immunohistochemical expression of VEGF, and NOS isoforms, as well as for VEGF and NO secretion in cell culture medium. Our immunohistochemical analysis showed that proliferating MSCs derived from human skin exhibit VEGF expression at cytoplasmic level as well as cytosolic and nuclear localization of all the three isoforms of NOS, even if with different patterns. In addition, our data evidenced the release of both VEGF and NO in cell culture supernatants. In conclusion, our results suggest that a therapeutic approach based on the human skin-derived MSCs may have a positive effect in wound healing conditions, through their ability to provide VEGF and NO to the damaged area.