Analysis of endothelial progenitor cells (EPCs) in the peripheral blood of pregnant women

Endothelial progenitor cells (EPCs) endowed with the potential to proliferate and differentiate into mature endothelial cells are present in adult peripheral blood and are though to contribute to the mainstenance of endothelial function and to sustain any request of angiogenesis, included endometrial repair after menstruation and neovascularization in the utero-placental circulation. To assess whether EPCs are increased in pregnant women, in the present study we enumerated EPCs in the peripheral blood during physiologic pregnancy. Among different antigenic profiles, EPCs were defined as CD34+/KDR+/CD133+ cells and quantified by flow cytometry directly in fresh blood samples. Mature circulating endothelial cells (CECs) identified as CD45 - /CD31+/CD145+ cells, were also analyzed. We observed that EPCs are markedly increased in pregnant women compared with agematched controls (p = 0.02). Intriguingly, also CECs resulted increased during pregnancy. These results may suggest that pregnancy per se promotes the proliferation and/or the mobilization of EPCs from the bone marrow into circulation. Because the fine mechanisms governing angiogenesis have not yet been clearly elucidated our data will be related to plasmatic levels of angiogenic factors and sexual hormones.