Placental hypoxia-induced alterations in vascular function, morphology, and endothelial barrier integrity

Abstract

Preeclampsia (PE) is a pregnancy-related disorder characterized by hypertension and proteinuria that affects 3-10% of all pregnancies. Although its pathophysiology remains obscure, placental hypoxia-induced oxidative stress and alterations in vascular function, morphology, and endothelial barrier integrity are considered to play a key role in the development of preeclampsia. In this study, placental villous explants of noncomplicated placentae and BeWo cells were subjected to hypoxia. The effect of placental hypoxic-conditioned medium (HCM) on intraluminal-induced contraction and endothelial barrier integrity in chorionic arteries was investigated using pressure myography. The impact of BeWo cell HCM on endothelial cell viability, reactive oxygen species formation and inflammation was also determined. Alterations in arterial morphology and contractile responsiveness to the thromboxane A2 analog (U46619) after exposure to placental HCM were examined immunohistochemically and by wire myography, respectively. Intraluminal administration of placental HCM induced vasoconstriction and increased the endothelial permeability for KCl, which was concentration-dependently prevented by quercetin. Placental and BeWo cell HCMs decreased endothelial cell viability, increased the production of reactive oxygen species and enhanced the secretion of IL-6 and IL-8. The cross-sectional area of the arterial media was increased upon exposure to placental HCM, which was associated with increased vascular proliferation and contractile responsiveness to U46619, and all of these effects were prevented by the antioxidants quercetin and RRR-α-tocopherol. This study is the first to comprehensively demonstrate the link between factors secreted by placental cells in response to hypoxia and vascular abnormalities and paves the way for new diagnostic approaches and therapies to better protect the maternal vasculature during and after a preeclampsia-complicated pregnancy.

Abnormal cerebral microvascular perfusion and reactivity in female offspring of reduced uterine perfusion pressure (RUPP) mice model

“…The RUPP model results in placental ischemia, a critical event in the pathophysiology of PE. 36 This damage leads to oxidative stress in the placenta that produces secretion of factors involved in endothelial cell dysfunction 37 and multisystem alterations, including structural and functional kidney alterations leading to proteinuria. 38 In the placenta, structural compensatory adaptations, including increased placental weight and enlargement of the labyrinth area, are present 35 and confirmed in our study.…”

Oxidative stress induces release of mitochondrial DNA into the extracellular space in human placental villous trophoblast BeWo cells

“…Findings from these studies suggest an association between increased ROS production and cell death in placental (20,38,39) and non-placental cells (40,41). Here, we posit that this relationship also mediates the release of mtDNA into the extracellular space in trophoblast cell cultures.…”

“…In the placental cell lines, BeWo, JEG-3, and Swan-71, exposure to rotenone or antimycin A led to a dose-dependent increase in ROS, and also led to apoptotic cell death in rotenone treated cells after 4 hours(20). ROS-mediated increase in apoptotic cell death has also been reported in response to hypoxia or hydrogen peroxide (38, 39). Non-apoptotic cell death and release of mtDNA, however, were not determined in any of these previous investigations.…”

“…Exposure to pharmacological inhibition of the electron transport chain, either with rotenone or antimycin A (inhibitors of complexes I and III, respectively) or other cytotoxic agents such as hydrogen peroxide and low levels of oxygen are often used to induce ROS production in in vitro experimental set ups (37). Findings from these studies suggest an association between increased ROS production and cell death in placental (20, 38, 39) and non-placental cells (40, 41). Here, we posit that this relationship also mediates the release of mtDNA into the extracellular space in trophoblast cell cultures.…”

Hypoxia-induced mitochondrial abnormalities in cells of the placenta

“…As previously described [ 20 ], intracellular ROS levels were quantified using the 2’,7’-dichlorodihydrofluorescein diacetate (DCFH-DA)-assay. 72 h after cell seeding, cells were washed twice with 150 μl HBSS, incubated for 1 h with 100 μl H 2 DCFH-DA (50 μM) and washed twice again with 150 μl HBSS.…”