Highlighting the R1 and R2 VEGF receptors in placentas resulting from normal development pregnancies and from pregnancies complicated by preeclampsia.

Preeclampsia (PE), a pathological entity characterized by hypertension and pregnancy-related proteinuria, is a medical condition of incompletely known etiopathogenesis. Placental defects and placental angiogenesis may be a cause of this condition. The main factor that controls angiogenesis in the early stages of placental development is vascular endothelial growth factor A (VEGF-A) and its two receptors, namely VEGFR-1 and VEGFR-2. This study analyzed the immunohistochemical (IHC) expression of the two VEGF receptors, R1 and R2, in pregnancies complicated by PE compared to pregnancies with a normal evolution. The pregnancies included into the study for the harvesting of placental tissue to be microscopically analyzed were divided into two groups: the group of physiological pregnancies (22 pregnancies) and the group of pregnancies complicated by preeclampsia (13 pregnancies). For the microscopic analysis, we used the Hematoxylin-Eosin (HE), Masson's trichrome and IHC stainings. The microscopic aspects of HE and Masson's trichrome stainings most commonly found in normal development pregnancies underlie the normal process of placental senescence. In the case of pregnancies complicated by PE, the microscopic analysis of the placentas revealed fibrinoid necrosis of the vascular wall, lipid-loaded endothelial cells, diffuse trophoblastic hypertrophy, microinfarctions, calcification areas, fibrin deposits, vascular-syncytial membrane surface reduction, basement membrane thickening. According to the established marker intensity score, the VEGFR-1 and VEGFR-2 receptors were more pronounced in the placentas resulting from pregnancies complicated by preeclampsia. The present study brings arguments that support the major regulatory role of VEGF-A and of the two receptors in the normal or pathological angiogenesis in the placenta, and implicitly in the pathogenesis of preeclampsia. Further studies are needed for a more comprehensive analysis of the stages in which these factors cause alteration of the placental angiogenesis and vasculogenesis processes, so that they can intervene effectively in the treatment or prevention of this disease.