Vasculogenesis: a new piece of the endometriosis puzzle.

BACKGROUND; Endometriosis is a complex disease with a multifactorial pathogenesis, which is crucially dependent on the development of new blood vessels. Based on the current literature, the present review highlights the fact that the neovascularization of endometriotic lesions is not only driven by angiogenesis, but also involves de novo formation of microvessels from circulating endothelial progenitor cells (EPCs). This process, termed post-natal vasculogenesis, is a characteristic of various pathogenic conditions, such as tumour growth and atherosclerosis, and typically comprises the activation, mobilization and recruitment of bone marrow-derived EPCs to the sites of tissue hypoxia. METHODS ; Literature searches were performed in PubMed, MEDLINE and ISI Web of Knowledge for publications focusing on vasculogenesis in the endometrium and endometriotic lesions. RESULTS ; Recent studies indicate that up to 37% of the microvascular endothelium of ectopic endometrial tissue originates from EPCs, partly controlled by the stromal-cell-derived factor-1/chemokine receptor type 4 axis. Accordingly, blockade of EPC recruitment effectively inhibits the formation of microvascular networks in developing endometriotic lesions, indicating that vasculogenesis represents an integral part of the pathogenesis of endometriosis. CONCLUSIONS ; The involvement of vasculogenesis in endometriosis may offer the exciting opportunity for the future establishment of novel diagnostic and therapeutic strategies for this frequent gynaecological disease.