ADRENOMEDULLIN, A NEW VASOACTIVE PEPTIDE, IS INCREASED IN PREECLAMPSIA

Adrenomedullin is a novel peptide that elicits a long-lasting vasorela xant activity. Recently, we found high concentrations of adrenomedulli n in maternal and umbilical cord plasma and in amniotic fluid in full- term human pregnancy, indicating a role of this peptide during gestati on. To investigate the possibility that adrenomedullin is involved in the pathophysiology of preeclampsia, we measured its concentration in maternal and fetoplacental compartments, We studied 12 normotensive no npregnant women, 13 hypertensive nonpregnant subjects, 29 patients wit h preeclampsia, and 30 normotensive pregnant women. In all patients, p lasma was collected from the cubital vein, and amniotic fluid samples were obtained by transabdominal amniocentesis or at elective cesarean section. Plasma samples from umbilical vein and placental tissues were collected at delivery. Adrenomedullin was assayed on plasma and amnio tic fluid samples using a specific radioimmunoassay, and its localizat ion and distribution on placental sections was determined by immunohis tochemistry. Adrenomedullin concentrations were higher in hypertensive than in normotensive nonpregnant patients. Pregnant women had higher adrenomedullin levels than nonpregnant subjects, although maternal pla sma adrenomedullin concentrations did not differ between normal pregna nt and preeclamptic women. Preeclamptic patients showed higher concent rations (P<0.01) than normotensive pregnant women of adrenomedullin in amniotic fluid (252+/-29 versus 112+/-10 fmol/mu mol creatinine) and umbilical vein plasma (18.1+/-2.1 versus 8.5+/-1.1 fmol/mL). Increased local production of adrenomedullin is associated with preeclampsia, T he fetus seems to be responsible for the higher levels of this hormone . Increased adrenomedullin concentrations may be necessary to maintain placental vascular resistance and/or fetal circulation at a physiolog ical level.