Objective: To compare maternal and umbilical venous big endothelin (big ET) and endothelin-1 (ET-1) levels of pregnancies complicated by severe preeclampsia (PE) or HELLP-syndrome to those of a well-matched normotensive pregnant control group.
Methods: We measured plasma levels of ET-1 and big ET in 16 patients with severe PE and 14 patients with HELLP-syndrome by commercially available RIAs and compared them with those of well-matched normotensive pregnant controls. Additionally, the umbilical venous ET-1 and big ET levels were determined in 10 corresponding newborns.
Results: The plasma concentrations of ET-1 and big ET were significantly higher in patients with severe PE and especially in women with HELLP-syndrome when-compared with controls. The molar ratios of big ET to ET-1 were significantly lower in the two study groups. The levels of ET-1 and big ET were higher in umbilical venous plasma than in maternal plasma, but there were no significant differences in the umbilical venous concentrations between normotensive and by severe PE or HELLP-syndrome complicated pregnancies.
Conclusions: These findings suggest that ET-1 may be considered as a marker of endothelial injury in by severe preeclampsia or HELLP-syndrome complicated pregnancies. The increase of the ET-1 plasma levels may be due, at least in part, to changes in the conversion of big ET to ET-1 by the endothelin-converting enzyme.