Activin A and inhibin A as possible endocrine markers for pre-eclampsia

Background Inhibin A and activin A are produced by the placenta during human pregnancy. This study aimed to measure circulating concentrations of inhibin A, proαC-containing inhibins, and activin A in the serum of women with pre-eclampsia and of healthy matched control pregnant women, and to establish the molecular-weight forms of circulating inhibin A and activin A in pre-eclampsia. Methods In a retrospective cross-sectional study, blood samples were taken from 20 women in hospital with established pre-eclampsia, and from 20 control pregnant women attending antenatal clinics, who were matched for duration of gestation (pre-eclampsia mean 29·15 [SD 3·75] weeks; controls 29·30 [3·93] weeks), parity, and maternal age. Serum samples were analysed for inhibin A, inhibin B, proαC, and activin A. Pooled samples of control (n=3) and pre-eclampsia serum (n=3) subsequently underwent fast protein liquid chromatographic analysis to assess the molecular-weight forms of inhibin A and activin A. Results are expressed as mean and SD for all variables measured. Findings Serum concentrations of inhibin A, activin A, and proαC were significantly higher in pre-eclampsia than in control normal pregnancy (inhibin A 3·05 [1·8] vs 0·36 [0·14] ng/mL, p<0·001; activin A 38·08 [25·88] vs 3·95 [2·32] ng/mL, p<0·001; proαC-containing inhibins 2·2 [0·81] vs 0·71 [0·33] ng/mL, p<0·001). Inhibin B concentrations in maternal serum were not increased. Molecular-weight forms of inhibin A (32 kDa) and activin A (>100 kDa) were similar in pre-eclampsia and normal pregnancy. The mean concentrations of hCG were 59·05 [43·98] and 16·3 [8·72] ng/mL, respectively. Interpretation Higher maternal serum concentrations of inhibin A, proαC, and total activin A in pre-eclampsia than in control pregnancies could be helpful in the diagnosis of pre-eclampsia. These changes are interpreted as further evidence for trophoblast dysfunction in pre-eclampsia.