Something Old, Something New, Something Borrowed… About the Placenta.

The connection between the mother and the child has been considered one of the strongest bonds in nature. Though there are numerous factors that can influence the establishment of pregnancy, in its essence, three are considered major: a good quality embryo, a receptive endometrium, and successful cross-talk between them. The placenta, which derives from the trophoblast of the embryo, develops when a successful implantation occurs. It is an ephemeral organ through which the turnover of nutrients, gases, and waste molecules is realized. It serves as a barrier and can provide the embryo with immune factors. Placental disorders are observed in some rare but life-threatening obstetric conditions like preeclampsia (PE), fetal growth restriction (FGR), gestational trophoblastic diseases (GTDs), and gestational diabetes mellitus (GDM). The etiology and pathogenesis of some are still partially enigmatic. Our attention in this review was driven by the participation of small RNA molecules-miRNAs and piRNAs-as potential epigenetic modulators of genes that play a pivotal role in placental functioning. In this study, we analyze the influence of these epigenetic factors on the mechanisms of the development of preeclampsia. The molecular approach for understanding placental disorders may help new diagnostic and therapeutic solutions to be found.