Placental angiogenin inhibitor (ribonuclease inhibitor), a novel gene in pre-eclampsia

There is convincing evidence that imbalance between angiogenic and anti-angiogenic factors play an important role in the pathophysiology of pre-eclampsia. Angiogenin, a member of the RNase A super family, is a potent inducer of angiogenesis and serum levels are shown to be elevated in pre-eclampsia. We hypothesize that placental expression of angiogenin inhibitor which binds and blocks the activity of angiogenin is altered in pre-eclampsia and may play a role in its pathophysiology. Placental expression of angiogenin inhibitor was measured in term placentae of 15 women with preeclampsia and 16 normal pregnant controls. The women were matched for age, parity and gestational age. Placental tissue was collected immediately after delivery and stored at -80°C until studied. Angiogenin inhibitor gene expression was measured using real-time quantitative polymerase chain reaction (rt-QPCR). The results were standardized using the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as reference gene. The mRNA expression of angiogenin inhibitor gene was significantly increased in preeclamptic placentae compared to normal pregnant controls [0.44 (0.174-1.048) versus 0.091 (0.029-0.301), median and interquatile range, p=0.027 for pre-eclampsia and normal controls respectively]. There was no correlation between angiogenin inhibitor gene expression and maternal age, blood pressure, platelet count, gestation age, birth weight of the baby in pre-eclampsia and normal pregnancy. This study showed that placental expression of the angiogenin inhibitor gene is significantly increased in pre-eclampsia and may play a role in its pathophysiology.