Vascular morphogenesis in the ovary

Vascular morphogenesis through mechanisms of vasculogenesis, angiogenesis a nd intussusception is associated primarily with embryonic and fetal develop ment and is down-regulated in the healthy adult. Physiological angiogenesis in the adult is restricted to the female reproductive system where it occu rs cyclically in the ovary and the uterus as well as pregnancy-associated i n the placenta and in the mammary gland. Of all the different organs, the c yclic corpus luteum of the ovary is the organ site with the strongest physi ological angiogenesis. The hormonally regulated cyclic processes in the cor pus luteum are characterized by discrete phases of blood vessel growth, ves sel maturation and vessel regression. This chapter discusses the morphologi cal changes of the vasculature in the cyclic corpus luteum in relation to t he regulating molecular mechanisms. These data establish the dynamic proces ses in the ovarian corpus luteum as a unique system for studying all steps of the angiogenic cascade, including vessel maturation and vessel regressio n. Inhibition of angiogenesis impairs the normal ovarian cycle, reflecting that angiogenesis is rate-limiting for ovulation and growth of the corpus l uteum and may, thus, be a potential target for therapeutic intervention in the reproductive function.