Preeclampsia (PE) is a gestational disorder and genetic and epigenetic alterations can affect its pathogenesis. Some evidences showed that the altered expression of miRNAs in the placentas complicated by PE. The blood samples from 219 PE and 242 normotensive pregnant women and placental tissue samples from 111 PE and 119 normotensive women were collected. MiR-146a and miR-149 polymorphisms were genotyped in blood samples and placentas using PCR-RFLP method. The frequencies of maternal miR-146a rs2910164 GC and CC genotypes did not differ between PE and control groups. However, the miR-146a rs2910164 G/C polymorphism was associated with an increased risk of PE in dominant (OR 1.5, 95% CI 1-2.1; P = 0.04) and allelic (OR 1.4, 95% CI 1-1.9; P = 0.04) but not recessive models. Moreover, the maternal GC and CC genotypes were associated with a 1.9- and 3.4-fold increased risk of severe PE (OR 1.9, 95% CI 1.1-3.2; P = 0.02 and OR 3.4, 95% CI 1.3-9; P = 0.01, respectively) and miR-146a rs2910164 polymorphism could increase risk of severe PE in dominant and recessive models (OR 2.1, 95% CI 1.3-3.4; P = 0.004 and OR 2.6, 95% CI 1-6.7; P = 0.04). The placental miR-146a rs2910164 polymorphism was associated with PE susceptibility in dominant (OR 1.8, 95% CI 1.1-3; P = 0.03) and allelic models (OR 1.7, 95% CI 1.1-2.5; P = 0.02). The frequencies of maternal and placental miR-149 rs2292832 genotypes were not different between two groups and these genotypes were not associated with PE or severe PE risk. In conclusion, according to logistic regression analysis the maternal/placental miR-146a rs2910164 G/C polymorphism was associated with PE and/or severe PE risk.
Keywords: Placenta; Polymorphism; Pre-eclampsia; microRNAs.