Advanced glycation end products as an upstream molecule triggers ROS-induced sFlt-1 production in extravillous trophoblasts: a novel bridge between oxidative stress and preeclampsia. 
Although abnormal soluble fms-like tyrosine kinase-1 (sFlt-1) production is thought to be an important factor in the pathogenesis of pre-eclampsia, the mechanisms that regulate the production of sFlt-1 during pre-eclampsia are unclear.  Accumulation of advanced glycation end products (AGEs) is prevalent in obesity, advanced maternal age, diabetes mellitus, and polycystic ovary syndrome.  Alterations in the regulation and signaling of angiogenic pathways have been considered as a link between these conditions and pre-eclampsia.  The purpose of this study was to explore the possible effects of AGEs on sFlt-1 secretion in extravillous trophoblasts (EVT).  A EVT cell line (HRT-8/SVneo) was treated with various concentrations of AGEs-BSA.  The mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in EVT were detected with real-time polymerase chain reaction.  The secretion of sFlt-1, VEGF, and PlGF protein from EVT was measured with ELISA.  The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA.  Exposure of EVT to AGEs-BSA induced increased intracellular ROS generation and overexpression of sFlt-1 at mRNA and protein levels in a dose dependent manner.  Anti-RAGE immunoglobulin G or apocynin (an inhibitors of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels.  Our data suggested that AGEs may be a new class of important mediator in the regulation of angiogenic pathways of EVT.  Accumulation of AGEs might contribute to the pathogenesis of preeclampsia by promoting sFlt-1 production through activation of RAGE/NADPH oxidase dependent pathway in EVT.