The possible role of endothelial cells in hypertensive disorders during pregnancy

To clarify the role of endothelial cells in pregnancy-related hypertensive disorders, we studied the cytotoxic effect of sera from normal pregnant women and from gravidas with various hypertensive complications of pregnancy.

We obtained serum samples from 84 Japanese women: 17 with preeclampsia, ten with gestational hypertension, six with chronic hypertension, five with chronic hypertension with superimposed preeclampsia, 21 normal gravidas, and 25 healthy nonpregnant women. Endothelial cell injury was measured by the release of radiolabeled chromium from the cells into the culture medium.

The mean (+/- standard error of the mean) values of chromium 51 release in preeclampsia, gestational hypertension, chronic hypertension, chronic hypertension with superimposed preeclampsia, normal pregnancy, and healthy nonpregnant women were: 21.9 +/- 2.1, 10.0 +/- 2.0, 9.2 +/- 2.3, 12.9 +/- 0.8, 8.4 +/- 1.4, and 7.3 +/- 1.6%, respectively. Normal pregnant and nonpregnant subjects did not differ with respect to endothelial cell injury. Sera from women with preeclampsia demonstrated significantly greater endothelial cell injury than did sera from normal gravidas. Subjects with the three other categories of hypertensive disorders did not differ significantly from normal gravidas.

Preeclampsia is characterized by the presence of a serum factor cytotoxic to endothelial cells. Therefore, the mechanism responsible for the increase in blood pressure differs between women with preeclampsia and those with other hypertensive disorders in pregnancy.