Soluble Vascular Endothelial Growth Factor Receptor-1 (sFLT-1) Mediates Downregulation of FLT-1 and Prevents Activated Neutrophils From Women With Preeclampsia From Additional Migration by VEGF

Abstract
Neutrophil activation and increased migration is associated with preeclampsia and is resolved after delivery. Preeclampsia is an inflammatory disorder where altered levels of vascular endothelial growth factor (VEGF) and the circulating soluble fms-like tyrosine kinase 1 (sFlt-1) have a pathogenic role. VEGF, by binding to FLT-1, induces leukocytic chemotaxis. We studied expression and function of FLT-1 in maternal neutrophils during preeclampsia and normal pregnancies. Analysis of maternal neutrophils showed the relationship between FLT-1 expression and week of gestation. Preeclamptic women express lower FLT-1 and sFLT-1 in neutrophils. In contrast, serum levels of sFLT-1 in patients with preeclampsia are increased and, therefore, inhibit upregulation of FLT-1 in neutrophils by neutralizing VEGF. VEGF-dependent FLT-1 expression is regulated by changing FLT-1-promoter activity. Promoter activity is decreased by sFLT-1. In vitro experiments demonstrated that migration of neutrophils is regulated by VEGF vi...