Figure 2

Immunohistochemical analysis of Snail and e-cadherin proteins expression in human normal term, preeclamptic and preterm placentas. E-cadherin (stained brown) is present in the basement membranes of the villi and, to a lesser extent, in the cytoplasm of VCT where it forms a connection between neighboring VCTs, and between VCT and overlying SynTB (arrowheads). Snail (stained red) is localized mostly in the nuclei of VCT and mesenchymal cells (short arrows). A normal placenta (A) and a preeclamptic placenta (B) are shown. In preeclampsia, there is a significant reduction in Snail expression. The premature placenta (C) shows a similar staining pattern to the term placenta. The maternal-fetal interface of a preterm placenta (D) reveals expression of Snail in EVT (long arrows), which lack e-cadherin on their membranes. Note that EVTs which express e-cadherin are Snail negative. The loss of e-cadherin by EVT is believed necessary for proper invasion and implantation