Endometrial angiogenesis: physiology and clinical implications.

Angiogenesis is the process of formation of new blood vessels from existing ones (in this it differs from vasculogenesis, the de novo formation of blood vessels in the embryo). With the exception of the female reproductive tract, healthy mature human tissues do not display angiogenesis to any significant extent, except in response to trauma. In the ovary and uterus, on the other hand, extensive vascular remodelling and formation of new vessels occurs on a regular cyclical basis and forms the bedrock of preparations for the implantation of the early embryo. Research into normal human fertility and its regulation is likely therefore to benefit from an elucidation of the processes involved in angiogenesis. In addition, pathological conditions relating to the reproductive tract appear in some cases to involve aberrant angiogenesis, and future research may lead to new therapeutic measures that may become effective treatments for these conditions. Finally, female reproductive biology provides a unique window into angiogenesis, and knowledge derived from this area is likely to add substantially to our knowledge of this major physiological and pathological process.