Endometrial angiogenesis, vascular maturation, and lymphangiogenesis.

Angiogenesis, arteriogenesis or vessel maturation, and lymphangiogenesis comprise a continuum of vascular development, with overlap and interaction between the mechanisms by which they are controlled. These processes are of clinical interest because they play roles in endometrial repair, placental development, and in gynecological disorders including endometrial cancer, endometriosis and abnormal uterine bleeding. Using mouse models we have shown that estrogen can be either proangiogenic or antiangiogenic in endometrium. Progesterone alone is proangiogenic, although this can be moderated by pretreatment with estrogen. Arteriogenesis also increases in response to progesterone, and this effect is not inhibited by estrogen. Lymphatics account for 13% of all vessels in the human functionalis compared to 57% in the basalis. Many of the basalis lymphatic vessels are closely associated with spiral arterioles and this intimate connection may provide a mechanism for paracrine communication between the functionalis and the arteries supplying the endometrium.