Placental vasculature in health and disease.

Both angiogenesis and vasculogenesis occur during normal placental development. Additionally, the placenta undergoes a process of vascular mimicry (also referred to as pseudo-vasculogenesis) where the placental cytotrophoblasts that invade the spiral arteries convert from an epithelial to an endothelial phenotype during normal pregnancy. Failure of placental angiogenesis and pseudo-vasculogenesis during placental development has been linked to the pathogenesis of preeclampsia and related disorders such as intrauterine growth restriction. This review discusses placental vascular development during health and in disease with a focus on accumulating recent evidence that the maternal clinical syndrome of preeclampsia may be due to the result of excess antiangiogenic factors liberated by the diseased placenta.