Alteration of the adrenomedullin receptor components gene expression-associated with the blood pressure in pregnancy-induced hypertension.

Adrenomedullin (AM) is a potent vasodilator. Pregnancy-induced hypertension (PIH) is a common cause of maternal or fetal mortality. We measured the ch anges of adrenomedullin receptor components gene expression, receptor activ ity-modifying protein 2 (RAMP2) and calcitonin receptor-like receptor (CRLR ), at feto-maternal tissues in human normotensive pregnant women and pregna ncy-induced hypertensive women by Northern blot analysis. Samples of the pl acenta, uterine muscle, umbilical artery, and fetal membranes were obtained from each patients under informed consent. RAMP2 mRNA significantly decrea sed in the umbilical artery(54%, P<0.01) and uterus(53%, P<0.01) of the pat ients with PIH. CRLR mRNA also significantly decreased in both tissues of t he patients with PIH. On the other hand, the RAMP2 mRNA was significantly i ncreased in the fetal membrane of the patients with PIH. In addition, there was a significant negative correlation between the RAMP2 mRNA levels in th e umbilical artery(systolic; r=-0.553, P<0.01, diastolic; r=-0.552, P<0.01) and uterine muscle(systolic; r=-0.563, P<0.01, diastolic; r=-0.553, P<0.01 ) and blood pressure. However, there was no correlation between the mRNA le vel and blood pressure in fetal membrane and placenta, suggesting that ther e is no close relationship to the pathogenesis in PIH. These findings sugge sted that the reduced expression of adrenomedullin receptor component in um bilical artery and uterus may have some role in PIH.