Alterations of angiopoietin-related growth factor (Angptl6) during pregnancy and in pre-eclampsia

The aim of this study was to clarify the alterations of angiopoietin-related growth factor (AGF, also known as Angptl6/ARP5) in the serum of normally pregnant women and pre-eclamptic women and to explore the role of AGF in pre-eclampsia.

Thirty healthy non-pregnant women, 118 normally pregnant women (30 at 6-12 gestational weeks, 30 at 13-28 weeks and 58 at 29-40 weeks, respectively) and 46 pre-eclamptic women were recruited. Fasting blood samples were obtained from all subjects. Fifteen women of healthy pregnant women provided their blood samples at 24 and 48 h after cesarean section, respectively. Enzyme-linked immunosorbent assay was used to determine the serum level of AGF.

Serum levels of AGF were significantly higher in normally pregnant women than non-pregnant women (P < 0.001 of all). Although serum AGF of the first trimester was significantly higher than that of the second trimester (P = 0.033), there were no significant differences of serum AGF in the comparison between the first and third trimester (P = 0.064) and between the second and third trimester (P = 0.546). Serum AGF significantly decreased after delivery (P < 0.05). There were no significant differences in AGF of maternal serum between pre-eclamptic women and normally pregnant control women (P = 0.285). There were no significant differences in circulating AGF concentration between non-pregnant women and postpartum groups (P = 0.052 for 24 h after delivery and P = 0.083 for 48 h after delivery).

The serum level of AGF was elevated in normal pregnancy compared with non-pregnant women, suggesting that placenta is an important source of circulating AGF during pregnancy.