Hypoxic trophoblast-derived sFlt-1 may contribute to endothelial dysfunction: implication for the mechanism of trophoblast-endothelial dysfunction in preeclampsia.

The maternal systemic disorder of widespread endothelial dysfunction is a primary focus in understanding the development of preeclampsia. sFlt-1 (soluble fms-like tyrosine kinase receptor 1), an endogenous inhibitor of VEGF (vascular endothelial growth factor), may play important roles in endothelial dysfunction. The present study aimed to determine whether hypoxic trophoblast-derived sFlt-1 could lead to endothelial dysfunction by establishing a cocultured model of anoxic TEV-1s (human first-trimester extravillous trophoblasts) and HUVECs (human umbilical vein endothelial cells). The results showed that the hypoxic treatment significantly promoted sFlt-1 mRNA and protein expression in TEV-1s in a time-dependent manner compared with the effect in HUVECs. When HUVECs were cocultured with anoxic TEV-1s, the endothelial function, which was characterized by NO (nitric oxide) synthesis and monolayer barrier function of HUVECs, were notably decreased, accompanied by increasing sFlt-1 and decreasing VEGF in cell-conditioned medium. Moreover, the observed endothelial dysfunction described above was consistent with the dysfunction observed in VEGF siRNA-treated cultures. The findings presented herein imply that chronically hypoxic trophoblasts may release sufficient sFlt-1 to cause endothelial dysfunction by depriving cells of VEGF activity.