The apelinergic system in fisiological pregnancy and in preeclampsia

Object: Apelin is an endogenous ligand of the human orphan receptor APJ. Apelin is involved in the regulation of blood pressure, blood flow and central control of body fluid homeostasis in different organs. In placenta vasculogenesis, blood pressure and flow are dramatically important to allow a normal embryonic and fetal growth and development, the aim of the present study was to investigate the immunohistochemical distribution of apelin and APJ in normal placentae throughout pregnancy and in preeclamptic placentae. Methods: Samples from first trimester were obtained from uterine evacuations (n=15) with a gestational age from 5 to 14 weeks, samples from third trimester were obtained from cesarean sections (n=15) with a gestational age from 28 to 40 weeks. Samples of pregnant patients with pre-eclampsia were obtained from cesarean delivery (n=15) and gestational age ranged from 35 to 40 weeks. All the collected specimens were immediately fixed in formalin for immunohistochemistry. Results: We observed a decrease of apelin expression from first to third trimester of gestation in placental cells and stroma of placental villi, in contrast with an increased expression of APJ expression in the cytoplasm of cytotrophoblast cells and in the cytoplasm of endothelial cells. In contrast, in preeclampsia-complicated placentae we observed an intense expression of both apelin and APJ receptor in all placental compartments. Conclusions: Our data seem to confirm that apelin and APJ might play a role in the regulation of fetal development regulating a correct formation of human placenta during gestation. Moreover, their strong expression in preeclampsia-complicated placentae probably suggest their involvement in the onset of this pathology. © Copyright 2006, CIC Edizioni Internazionali, Roma.