Mammalian blastocyst produces membranes that gradually attach in the endometrial epithelium and establish a close relationship between fetal and maternal circulatory systems for physiologic exchange. This fact results in the formation of a combined organ, the placenta. Placentation includes extensive neovascularization in maternal and embryonic placental tissues. Recent studies, particularly of genetically altered mice, have greatly improved our understanding of the molecular basis of the development of the vascular system. Numerous factors have been implicated in the regulation of the neovascularization process of the placenta. The aim of this article is to highlight briefly the pattern circulation of the rabbit term placenta as an example of the microvascularization of hemochorial placenta typical of humans and to summarize the main factors responsible for modulating the growth of decidual placental vessels and the vasculogenesis of the basal plate.
Copyright 2002 Wiley-Liss, Inc.