Maternal plasma adenosine and endothelin-1 levels in twin gestation complicated by preeclampsia

The aim of this study was to evaluate the relationship between the vascular resistance in uterine arteries and the maternal release of adenosine and endothelin-1 in twin gestations with and without preeclampsia. Uterine artery Doppler velocimetry and maternal arterial blood sampling were performed in 14 women with normal singleton gestation, nine women with singleton gestation with preeclampsia, eight women with dichorionic twin gestation without preeclampsia and six women with dichorionic twin gestation with preeclampsia at 28-34 weeks' gestation. In normal singleton gestations, the average maternal uterine arteries pulsatility index (PI), plasma adenosine and endothelin-1 levels were 0.64+/-0.07, 0.34+/-0.11 micromol/l and 1.29+/-0.31 pg/ml, respectively. In preeclamptic singleton gestations, increased vascular resistance in the uterine arteries (PI: 0.85+/-0.14, P<0.05) and the elevation of maternal arterial plasma adenosine (0.48+/-0.14 micromol/l, P<0.05) and endothelin-1 levels (1.91+/-0.55 pg/ml, P<0.05) were observed. In the normal twin gestation group, the average maternal vascular resistance of the uterine arteries (PI: 0.55+/-0.09) was lower than that in the normal singleton gestation group, while the average plasma adenosine levels (0.47+/-0.12 micromol/l) were higher than that in normal singleton gestation. On the other hand, significant increased plasma endothelin-1 concentrations (1.87+/-0.42 pg/ml) were observed in the preeclamptic twin gestation groups without changes in plasma adenosine levels or vascular resistance of uterine arteries. Our results indicate the presence of different mechanisms for the pathogenesis of preeclampsia between twin and singleton gestations.