Circulating endothelial progenitor cells biology and regenerative medicine in pulmonary vascular diseases

Pulmonary vascular disorders (PVDs) include primary or secondary diseases who ultimately influence the right heart function. Several researches showed that stem and progenitor cells may represent a novel approach in treating pulmonary hypertension. In particular, circulating endothelial progenitor cells (EPCs) are mobilized either from the bone marrow and/or arteries to replace dysfunctional endothelial cells and restore blood perfusion to ischemic tissues. They may deliver paracrine signals to stimulate local angiogenesis or may be physically incorporated within neovessels. Understanding the molecular mechanisms utilized by vascular endothelial growth factor (VEGF) to stimulate EPC might shed light on novel targets for regenerative medicine. Ca2+ machinery regulates proliferation, migration, tube formation, and, therefore, differentiation of EPCs may give valuable insights into the biology of these cells; the Ca2+ machinery in these cells is extremely plastic and may vary depending on their origin. In this paper, we review EPCs subtypes, their sources, biological properties, functional mechanisms and of course involvement in pulmonary vascular diseases.