Antiangiogenic and vascular-disrupting agents in endometriosis: pitfalls and promises

It is widely known that angiogenesis plays a key role in endometriotic lesion formation and development. Antiangiogenic treatments aimed at inhibiting new vessel formation have proven efficient in experimental models. However, as antiangiogenic strategies do not target pre-existing pericyte-protected vessels, they require chronic administration and are likely to be beneficial for early-stage disease only or to prevent recurrence after surgery. Moreover, they may have detrimental effects on reproductive function. Vascular-disrupting agents (VDAs) have emerged as a promising new tool for the treatment of tumors. VDAs target established blood vessels, resulting in tumor ischemia and necrosis. These agents may therefore be more efficient against advanced disease. Two major types of VDAs are being developed for cancer: ligand-directed VDAs using antibodies, peptides and growth factors to deliver toxic effectors to tumor endothelium; and small-molecule VDAs exploiting physiological differences between tumor and normal endothelium to induce acute vascular shutdown. The ongoing evolution in genomics and proteomics is revolutionizing the discovery of novel endothelial markers. Several studies suggest that the vasculature of endometriotic lesions may have particular pathophysiological properties, which could be exploited for the development of selective VDAs. The aim of this review is to explore the merits and limitations of vascular therapy for the treatment of endometriosis.