Likewise, it has been recently demonstrated that some cells, defined according to the International Society of Hematotherapy and Graft Engineering (ISHAGE) criteria as circulating hematopoietic progenitor cells (HPCs; CD34+CD45dimVEGFR2- and CD34+CD45dimCD133+VEGFR2-), were reduced in patients presenting clinical signs of endothelial dysfunction, and thus it was postulated that the number of HPCs might be an independent predictor of morbidity from cardiovascular diseases and a marker of atherosclerotic disease progression[44]. Here, CD34 is linked to endothelial dysfunction.