Pregnancy-induced hypertension is associated with an activation of endothelial cells

Abstract Objective: The aim of the study was to elucidate the biochemical and structural basis of the modifications in endothelial functions recently described in pregnancy-induced hypertension (PIH). Methods: Umbilical cords were obtained from 6 healthy pregnant women and 6 women affected by PIH. Endothelial cells were prepared by an adaptation of the method of Jaffe et al. The fluidity of the cellular membrane was assayed by the fluorescent probe 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). The fluid-phase endocytosis of the cells was studied by the measurement of the probe fraction internalized by endocytosis as described by Illinger. The morphological study was performed by transmission electron microscopy (TEM). Results: In comparison with endothelial cells from controls the cells from PIH women showed: (i) a significant decrease in the anisotropy values of TMA-DPH (P < 0.01), indicating an increased membrane fluidity; (ii) a higher relative fluorescence intensity of TMA-DPH after 5-min incubation (p < 0.01), consistent with an enhanced fluid-phase endocytosis; (iii) morphological features of activation with a hypertrophic Golgi apparatus and a dilated rough endoplasmic reticulum. Conclusions: The present results indicate an activation of endothelial cells during PIH, which might per se affect the vascular reactivity through modifications in the endothelial synthesis of vasoactive molecules.