Altered gene expression of endothelin-A and endothelin-B receptors, but not endothelin-1, in myometrium and placenta from pregnancies complicated by preeclampsia

Objective: The aim of the present study was to compare the mRNA expression of endothelin-1 (ET-1), ET-1 receptors ET A and ET B in myometrium and placenta obtained from biopsies collected from women with preeclampsia (n=10) or normal pregnant (n=12). Methods: The mRNA levels of ET-1, ET A and ET B were determined using RT-PCR and expressed as arbitrary units after correction for control GAPDH gene mRNA levels. Results: The mRNA levels of ET-1 in myometrium and placenta were not altered in women with preeclampsia compared to normal pregnant. The mRNA expression of ET A was significantly reduced (p<0.05) in both placenta and myometrium from women with preeclampsia. The mRNA levels of ET B were similar in placentas from both preeclamptic and normal pregnant women, but higher in myometrium (p<0.05) from women with preeclampsia. Conclusions: These results indicate that the higher levels of ET-1 seen in preeclamptic women do not depend on an altered mRNA transcription of ET-1. The significantly reduced mRNA expression of ET A receptor in myometrium and placenta in women with preeclampsia might represent downregulation of the receptors due to the increased levels of ET-1 in uteroplacental circulation in this disorder. Much more research is needed before the role of ET B receptors in preeclampsia can be clarified.