Abstract
Maternal endothelial dysfunction is a cental feature of preeclampsia (PE), a hypertensive disorder of pregnancy. Factors in the maternal circulation are thought to contribute to this endothelial dysfunction. Although understudied, factors in the fetal circulation may influence fetal endothelial cell interactions with endothelial progenitor cells as critical steps in placental angiogenesis. We hypothesize that cell-cell interactions that are important for pregnancy health are impaired by fetal serum from PE pregnancies and that 1,25(OH)2-vitamin D3 attenuates the negative effects of this serum on cell function. We tested the ability of fetal cord blood-derived endothelial progenitor cells [endothelial colony-forming cells (ECFCs)] to invade into established monolayers and capillary tubule-like structures of human fetal umbilical venous endothelial cells (HUVECs), while in the presence/absence of fetal cord serum from uncomplicated or PE pregnancies, and tested the ability of 1,25(OH)2-vitamin D3 to modulate the serum-mediated effects. PE cord serum reduced the invasion of fetal ECFCs into HUVEC monolayers or tubule networks. Vitamin D attenuated these effects of PE fetal serum on endothelial functional properties. Immunocytochemical studies revealed involvement of VE-cadherin contacts in interactions between ECFCs and mature fetal endothelial cells. PE cord serum reduces the ability of fetal endothelial progenitor cells to incorporate into fetal endothelial cell networks. Physiologic concentrations of vitamin D reverse these PE serum-mediated effects. These data appear consistent with lines of evidence that vitamin D has antipreeclampsia effects.