Porcine EPCs downregulate stem cell markers and upregulate endothelial maturation markers during in vitro cultivation

In recent years, interest in endothelial progenitor cells (EPCs) in the field of tissue engineering and regenerative medicine has increased tremendously. However, each clinical stem cell application requires prior validation through animal experiments. This study investigates the isolation and characterization of porcine EPCs from peripheral blood and the change of their cell surface marker expression during in vitro cultivation. RT-PCR demonstrated that the EPCs express stem cell markers CD34 and CD133, which decrease with in vitro cultivation time. Throughout the cultivation process EPCs did not express monocytic (CD14) or haernatopoietic marker (CD45). Surprisingly, the CD31 and VE-cadherin expression in EPCs was significantly higher than in endothelial cells (ECs). In contrast, the VEGFR2 and E-selectin expression was significantly lower than in ECs, but increased during the expansion process. This study clarifies the characteristic properties of porcine EPCs during cell culture and may help to improve the impact of EPC-based therapies in porcine animal studies. Copyright (C) 2009 John Wiley & Sons, Ltd.