Pregnancy programming and preeclampsia: identifying a human endothelial model to study pregnancy-adapted endothelial...

We have previously reported that the increase in vasodilator production in an ovine model pregnancy is underpinned by an increase in connexin 43 (Cx43) gap junction function, so allowing more uterine artery endothelial cells to produce a more sustained Ca(2+) burst response to agonist stimulation. Since activation of endothelial nitric oxide synthase (eNOS) requires elevated [Ca(2+)]i, it follows that the direct result of enhanced bursting in turn is an increase in nitric oxide (NO) production per cell from more cells, and for a longer period of time. Preeclampsia (PE) is associated with endothelial vasodilatory dysfunction, and the endocrine profile of women with PE includes an increase in a number of factors found in wound sites. The common action of these growth factors and cytokines in wound sites is to mediate Cx43 dysfunction through kinase phosphorylation and closure. Translational studies are now needed to establish if inhibitory phosphorylation of Cx43 in human endothelium is the cause of endothelial dysfunction in PE subjects and if so, to identify the kinase pathways best targeted for therapy in PE subjects. Consistent with this we have already shown endothelial Ca(2+) and NO responses of human umbilical vein from normal subjects are similar to that of ovine pregnant uterine artery, and that those same responses in cords from PE subjects are blunted to levels more typical of nonpregnant uterine artery. In this review we summarize the further evidence that growth factors and cytokines may indeed mediate endothelial dysfunction in PE subjects through closure of Cx43 gap junctions. We also consider how we may clinically translate our studies to humans by using intact umbilical vein and isolated HUVEC in primary culture for an initial screen of drugs to prevent deleterious Cx43 phosphorylation, with the ultimate goal of reversing PE-related endothelial dysfunction.