An increase of elastic tissue fibers in blood vessel walls of placental stem villi and differences in the thickness of blood vessel walls in third trimester pre-eclampsia pregnancies

This study has goals of examining whether pre-eclampsia may lead to an increase of elastic tissue fibers in blood vessel walls of placental stem villi or whether there are differences in the thickness of blood vessel walls within these villi when compared to normotensive pregnant women. Non-infarcted placental tissue samples from 28 participants with uncomplicated pregnancies and 26 patients with pre-eclampsia were obtained. After routine histological procedures, the sections were processed either for conventional Verhoeff staining for the demonstration of elastic fiber system. Paraffine sections from placenta biopsies prepared for light microscopic examination were gathered. In uncomplicated pregnancies, terminal villi blood vessels were observed with no stained elastic tissue fibers in most areas. In the pre-eclampsia pregnancy of human placenta, the elastic fibers significiantly increased in terminal villi blood vessel walls which were dark in color, using Verhoeff’s tissue stain, when comparing with the uncomplicated pregnancy group. Our results indicate that an increase of elastic tissue fibers in blood vessels of placental stem villus and terminal villi, and also an increase of wall thickness during pre-eclampsia.