Defining endothelial progenitor cells

Abstract

Human cord blood-derived endothelial progenitor cells (EPC) have been defined as circulating cells that express a panel of cell surface markers similar to those known to be expressed by vascular endothelial cells, that home to sites of hypoxia/ischemia upon infusion into experimental animal models, and participate in blood vessel formation (as analyzed by in vitro and in vivo methods). Although no specific marker for an EPC has been identified, a group of markers has been consistently utilized as a surrogate marker for cells purported to display vascular regenerative capacity. Since both hematopoietic and vascular endothelial subsets display many of the same cell surface antigens and both participate in new blood vessel formation, recent analyses have stressed the need to reconsider the use of the term EPC. This chapter reviews our current approaches to identifying human EPC and provides a brief summary statement for a new definition of an EPC.