Endothelial progenitor cells - Functional characterization

Increasing evidence suggests that circulating progenitor cells contribute to postnatal neovascularization. These cells home to sites of ischemia, adopt an endothelial phenotype, and contribute to new blood vessel formation. Hence, the identity of the circulating cells that contribute to neovascularization is not entirely clear. Bone-marrow-derived hematopoietic progenitor cells can give rise to endothelial cells and contribute to endothelial recovery and new capillary formation after ischemia. However, nonhematopoietic stem cells within the bone marrow and adipose-tissue-derived cells, as well as cardiac and neural progenitor cells, also differentiate to endothelial cells. Progenitor cells from the different sources may be useful to augment therapeutic vascularization. The present review article summarizes the different subtypes of (endothelial) progenitor cells that can give rise to endothelial cells, enhance neovascularization, and may be suitable for therapeutic neovascularization. (C) 2004, Elsevier Inc. All rights reserved.