Hypertension in pregnancy: Changes in activin a maternal serum concentration

Human placenta is the major source of activin A in maternal circulation. The aim of the present study was to evaluate maternal activin A serum concentration in pregnant women with chronic hypertension (n=14), pregnancy-induced hypertension (n=10) or pre-eclampsia (n=16). In the group of pregnant women with chronic hypertension and of healthy pregnant women (n=10) activin A was measured in samples collected longitudinally throughout gestation. Using a specific two-site enzyme-linked immunosorbent assay, it has been possible to measure maternal serum activin A concentration. In addition, the effect of recombinant human activin A administration on mean arterial pressure and heart rate in female rats have been also investigated. Mean ± SEM of maternal serum activin A concentration in pre-eclamptic women (57.4 ± 28.3 ng/ml), was significantly higher than in women with pregnancy-induced hypertension (14.8 ± 10.5 ng/ ml), chronic hypertension (10.3 ± 5.4 nglml) or healthy control women (9.2 ± 9.4 nglml) (P<0.01). Serum activin A levels evaluated 2 weeks after anti-hypertensive treatment were not significantly different in pre-eclamptic women. Moreover, when exogenous recombinant human activin A was administered in female rats arterial pressure or frequency of heart rate did not change. The present study showed that maternal serum activin A concentration is abnormally high in patients with pre-eclampsia. Thus, since the patients with chronic hypertension or pregnancy-induced hypertension have activin A concentration in the normal range of values, activin A may be a prognostic marker of hypertension in pregnancy.