Placental ischemia and changes in umbilical and uteroplacental arterial and venous hemodynamics

Considering the Effects and Maternofoetal Implications of Vascular Disorders and the Umbilical Cord

The umbilical cord is a critical anatomical structure connecting the placenta with the foetus, fulfilling multiple functions during pregnancy and hence influencing foetal development, programming and survival. Histologically, the umbilical cord is composed of three blood vessels: two arteries and one vein, integrated in a mucous connective tissue (Wharton's jelly) upholstered by a layer of amniotic coating. Vascular alterations in the umbilical cord or damage in this tissue because of other vascular disorders during pregnancy are worryingly related with detrimental maternofoetal consequences. In the present work, we will describe the main vascular alterations presented in the umbilical cord, both in the arteries (Single umbilical artery, hypoplastic umbilical artery or aneurysms in umbilical arteries) and the vein (Vascular thrombosis, aneurysms or varicose veins in the umbilical vein), together with other possible complications (Velamentous insertion, vasa praevia, hypercoiled or hypocoiled cord, angiomyxoma and haematomas). Likewise, the effect of the main obstetric vascular disorders like hypertensive disorders of pregnancy (specially pre-eclampsia) and chronic venous disease on the umbilical cord will also be summarized herein.

Identification of autophagic vacuoles and regulators of autophagy in villous trophoblast from normal term pregnancies and in fetal growth restriction

Fetal growth restriction (FGR) is a serious pregnancy complication associated with increased perinatal mortality and morbidity. Although the majority of cases with FGR result from placental dysfunction, the pathophysiology is incompletely understood. Autophagy is a physiological form of cell degradation exacerbated by nutrient and oxygen restriction, which are both thought to play a role in the aetiology of FGR. We hypothesized that autophagy is present in the normal human placenta and is exaggerated in FGR. Autophagy was assessed in electron micrographs from normal and FGR placentas and by Western blotting for LC3B and LAMP-2. The localization of regulators of autophagy was examined by immunohistochemistry. Culture of BeWo cells was used to investigate whether nutrient and/or oxygen deprivation can induce autophagy in trophoblast. Autophagy predominantly localized to the syncytiotrophoblast layer and autophagosomes were more frequent in FGR. The regulators LAMP-2, LC3B, Beclin-1, ATG 5, ATG9 and ATG16L1 were all present in villous trophoblast. LAMP-2 immunostaining was more punctate in FGR. In BeWo cells, culture in reduced oxygen tension and/or serum depleted conditions led to the appearance of autophagosomes which was associated with changes in LAMP-2 configuration. We conclude that autophagy in human term placenta may be involved in the placental dysfunction present in FGR.