Endothelial progenitor cell differentiation using cryopreserved, umbilical cord blood-derived mononuclear cells

Aim: To investigate the endothelial differentiation potentiality of umbilical cord blood (UCB), we induced the differentiation of endothelial progenitor cells (EPC) from cryopreserved UCB-derived mononuclear cells (MNC). Methods: MNC from cryopreserved UCB and peripheral blood (PB) were cultured in M199 medium with endothelial cell growth supplements for 14 d. EPC were characterized by RT-PCR, flow cytometry, and immunocytochemistry analysis. The proliferation of differentiated EPC was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, and vascular endothelial growth factor (VEGF) concentration was measured using an ELIS A kit. Characteristics of UCB-derived EPC were compared with those of PB-derived EPC. Results: A number of round-shaped cells were loosely attached to the bottom after 24 h culture, and numerous spindle-shaped cells began to appear from the round-shaped ones on d 7. Those cells expressed endothelial markers such as, Flt-1/VEGFR-1, ecNOS, VE-cadherin, von Willebrand factor, and secreted VEGF. The patterns of endothelial markers of EPC from PB and UCB did not show striking differences. The results of the proliferation and secretion of VEGF were also similar. Conclusion: We successfully cultured UCB cells stored at -196°C into cells with the quality of endothelial cells. Those EPC could be used for angiogenic therapeutics by activating adjacent endothelial cells and enhancing angiogenesis.