Endothelial Nitric Oxide Synthase Immunreactivity and the Ultrastructure of Endothelial Cells of Umbilical Artery in Normal and Preeclamptic Pregnancies

Abstract

Our objective was to investigate the endothelial nitric oxide synthase (eNOS) immuno-reactivity and the ultrastructure of endothelial cells of a human umbilical artery in both normal and preeclamptic pregnancies. The umbilical cords from normal and preeclamptic pregnancies were collected immediately after vaginal and abdominal deliveries. Umbilical arteries were isolated and fixed in 10% neutral formaline solution, embedded in paraffin, and then stained with hematoxylin and eosin (H&E) for the histologic investigation, and eNOS activation were examined in samples by streptavidine-biotine immunohistochemical methods. The arterial sections were also fixed in phosphate-buffered 2.5% glutaraldehyde solution (pH 7.2) for 3 h and post-fixed with 1% osmium tetroxide at 4°C for 2 h for the investigation of the ultrastructural examination. In the umbilical artery of preeclamptic pregnancies, endothelial cells were oval, triangular, or polygonal, and were disorganized. Some endothelial cells were separated by enlarged intercellular spaces. A dilated endoplasmic reticulum, swollen mitochondria, and vanished mitochondrial cristae were observed. The nuclei of some endothelial cells displayed deep invaginations and irregular outlines. Most endothelial cells had a high number of cytoplasmic vacuoles. In preeclampsia, eNOS immunoreactivity increased considerably in endothelial cells when compared to normal pregnancies. We believe that preeclampsia plays an important role in the pathogenesis of endothelial cell dysfunction and activation in the umbilical artery. However, the disturbance mechanism of endothelial cells is not known, and further studies are necessary to clarify the exact mechanism.

Ultrastructure of Human Umbilical Artery and Vein

“…We observed cytoplasmic vacuoles in endotelial cells in line with that reported in the literature. We also found tight junctions between endothelial cells as other workers stated (10). The amount of rough endoplasmic reticulum in the arterial endothelium increased in mid-gestation and become much more prominent at full-term (4).…”

Human Chorionic Gonadotropin Protects Vascular Endothelial Cells from Oxidative Stress by Apoptosis Inhibition, Cell Survival Signalling Activation and Mitochondrial Function Protection

“…Hence, the collapse of the mitochondrial membrane potential induced by MPTP opening could favour the release of Cytochrome c and downstream activation of effector caspases [33]. It is also notable that in endothelial cells from the umbilical artery of pre-eclamptic patients mitochondria have been found to be impaired [34,35].…”