ABNORMAL ENDOTHELIAL-CELL FUNCTION OF RESISTANCE ARTERIES FROM WOMEN WITH PREECLAMPSIA

OBJECTIVE: There is substantial indirect evidence that the vascular endothelium may be dysfunctional in preeclampsia and that reduced production of endothelial-derived vasodilators may account for the increased vascular resistance and enhanced pressor sensitivity characteristic of this disorder. In this study we directly investigated endothelial function by examining acetylcholine-mediated relaxation in small arteries dissected from the subcutaneous fat layer examined at the time of cesarean section. STUDY DESIGN: By means of a small vessel myograph we measured tension in resistance arteries of normal pregnant women (n = 12) and women with preeclampsia (n = 12) and assessed the contributions of vasodilatory prostanoids and endothelium-derived relaxing factor to endothelium-dependent relaxation, as elicited by acetylcholine, 1 nmol/L to 10 mumol/L, after precontraction with 3 mumol/L norepinephrine. RESULTS: Endothelium-dependent relaxation was impaired in arteries of women with preeclampsia compared with arteries from normotensive pregnant women. Endothelium-independent relaxation as assessed by sodium nitroprusside was not altered in the arteries from preeclamptic women. CONCLUSIONS: This study provides direct evidence of abnormal endothelial function in preeclampsia. No deficiency in endothelium-independent relaxation could be detected.