The relationships between maternal and placental polymorphisms of miR-196a2 and miRNA-499 genes and preeclampsia

Background: miRNAs are small non-coding RNAs with potential roles in the complications of pregnancy. We hypothesised links between polymorphisms in miRNA-196a2 and miRNA-499 in maternal blood and the placentas of patients with preeclampsia. Methods: The blood of 315 women with preeclampsia and 317 controls and the placentas of 103 PE and 133 healthy women were collected. The genotyping of both polymorphisms was performed by PCR-RFLP. Results: The maternal blood rs11614913 was unrelated to preeclampsia in genotype and allele models, but in placental tissue, the CT (odds ratio [95% CI] 0.5 [0.3-0.9, p = 0.018) and TT (0.4 [0.2-0.9] p = 0.033) genotypes alone and together (CT+TT v CC 0.5 [0.3-0.8] p = 0.009), and the T allele (0.6 [0.4-0.9], p = 0.019) were associated with lower risk of preeclampsia. The maternal blood rs3746444 CC genotype was more frequent in preeclampsia (2.2 [1.2-3.8] p = 0.008) and the recessive model (CC v TC+TT) was also significant (1.9 [1.1-3.3], p = 0.018), as was the C allele (1.4 [1.1-1.7] p = 0.014). In placental tissue, the increase in the frequency of the CC genotype was marginally significant (2.4 [1.0-5.8] p = 0.046). The maternal or placental miRNA-196a2 rs11614913 and miRNA-499 rs3746444 polymorphisms were unrelated to the severity of preeclampsia. Conclusion: The placental but not maternal miRNA-196a2 rs11614913 variant could be a protective factor for preeclampsia predisposition in all models except the recessive model. The maternal/placental rs3746444 CC genotype was in association with higher preeclampsia risk.