Increased pulmonary blood flow produces endothelial cell dysfunction in neonatal swine

SummaryPreeclampsia (PE), intrauterine growth restriction (IUGR) and abruption with or without fetal loss are associated with reduced uteroplacental blood flow, decidual vasculopathy, endothelial cell dysfunction, thrombosis, inflammation and hemorrhage. Our hypothesis is that reduced uteroplacental blood flow causes focal decidual hypoxia that generates vascular endothelial growth factor (VEGF). The latter acts directly on decidual endothelial cells to induce aberrant expression of tissue factor (TF), the primary initiator of coagulation. This in turn generates thrombin that induces: i) further TF expression; and ii) inflammatory cytokines. BothVEGF and TF induce aberrant angiogenesis-vessel maintenance reflected by endothelial cell fenestrations and induction of a prothrombotic surface causing both the decidual hemorrhage (i.e.abruption) and thrombosis (i.e.uteroplacental vascular insuf- ficiency) observed in these adverse pregnancy outcomes. This novel hypothesis is supported by our finding of TF expression in decidual endothelium of pregnancies complicated by IUGR and/ or fetal loss. Moreover, treatment of cultured endometrial endothelial cells with VEGF or thrombin induces TF protein and mRNA expression. Quantitative RT-PCR analysis indicates that thrombin enhances (>10-fold) the output of diverse inflammatory cytokines in these cultures. The greatest effect (>2-log) was seen on macrophage inflammatory protein 3 α (MIP3 α ). In vitro, thrombin results in endometrial endothelial cell aggregations and changes in the apoptotic pathway. Thus, we postulate that reductions in uteroplacental flow initiate a cascade of molecular effects leading to hypoxia, thrombosis, inflammation, and endothelial cell dysfunction resulting in untoward pregnancy outcomes.

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Vascular adaptation in pregnancy and endothelial dysfunction in preeclampsia

Journal of Endocrinology ◽

10.1530/joe-16-0340 ◽

2017 ◽

Vol 232 (1) ◽

pp. R27-R44 ◽

Cited By ~ 90

Author(s):

D S Boeldt ◽

I M Bird

Keyword(s):

Endothelial Cell ◽

Endothelial Dysfunction ◽

Cell Function ◽

Endothelial Cell Dysfunction ◽

Hypertensive Disorders Of Pregnancy ◽

Endothelial Cell Function ◽

Vascular Adaptation ◽

Cell Dysfunction ◽

Maternal Adaptation ◽

Flow Through

Maternal vascular adaptation to pregnancy is critically important to expand the capacity for blood flow through the uteroplacental unit to meet the needs of the developing fetus. Failure of the maternal vasculature to properly adapt can result in hypertensive disorders of pregnancy such as preeclampsia (PE). Herein, we review the endocrinology of maternal adaptation to pregnancy and contrast this with that of PE. Our focus is specifically on those hormones that directly influence endothelial cell function and dysfunction, as endothelial cell dysfunction is a hallmark of PE. A variety of growth factors and cytokines are present in normal vascular adaptation to pregnancy. However, they have also been shown to be circulating at abnormal levels in PE pregnancies. Many of these factors promote endothelial dysfunction when present at abnormal levels by acutely inhibiting key Ca2+ signaling events and chronically promoting the breakdown of endothelial cell–cell contacts. Increasingly, our understanding of how the contributions of the placenta, immune cells, and the endothelium itself promote the endocrine milieu of PE is becoming clearer. We then describe in detail how the complex endocrine environment of PE affects endothelial cell function, why this has contributed to the difficulty in fully understanding and treating this disorder, and how a focus on signaling convergence points of many hormones may be a more successful treatment strategy.

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