Ontogenesis of villi and fetal vessels in the human placenta

The ontogenesis of the villous and vascular arborescence in normal pregnanc y is reviewed. The emergence of the villi and the fetal vessels is describe d from early pregnancy to term together with the specializations of the vil li, vessels and capillaries observed in the last trimester, The expression, localization and role of the angiogenic growth factors (FGF, VEGF, PLGF, H GF) are described and discussed, Pathological pregnancies with hyper- and h ypocapillarization are related to altered oxygenation, The potential roles of growth factors are presented and hypotheses proposed which may provide a molecular basis for the development of the most frequent placental patholo gies. Copyright (C) 2001 S. Karger AG, Basel.