FIGURE 2.

Aberrant placentation and angiogenesis in preeclampsia. In normal pregnancy, cytotrophoblasts of fetal origin invade the maternal spiral arteries and replace endothelial cell layer. This action converts the spiral arteries from narrow highly resistant vessels to high-caliber capacitance vessels, which are capable of providing sufficient blood and nutrition supply to the fetus. During the process of vascular invasion, the cytotrophoblasts differentiate from an epithelial to an endothelial phenotype, a process referred to as pseudovasculogenesis, or vascular mimicry (Right). In preeclampsia, cytotrophoblasts fails to acquire invasive endothelial phenotype features, thus the invasion of the spiral arteries is inadequate leaving them narrow and highly resistant (Left). Modified with permission from Lam et al. (2005) and Powe et al. (2011).