Gene delivery of soluble vascular endothelial growth factor receptor-1 (sFlt-1) inhibits intra-plaque angiogenesis and suppresses development of atherosclerotic plaque

Intra-plaque angiogenesis plays an important role in the development of atherosclerotic plaque. Vascular endothelial growth factor (VEGF) is a major initiating factor in this pathologic progress. One selective and specific inhibitor of VEGF is soluble VEGF receptor-1 (sFlt-1). The anti-angiogenic utilization of sFlt-1 in treatment of atherosclerotic plaque has not been fully confirmed yet. Our study was designed to construct eukaryotic expression recombinant pEGFP-N1-sFlt-1, evaluate sFlt-1 recombinant's effects on endothelial cells proliferation and tube formation in vitro, and investigate effects of local high-expressed sFlt-1 on atherosclerotic plaque in vivo. Rabbit models of atherosclerotic plaque were established by high-lipid diet combined with injury induced by balloon catheter on iliac artery intima. Animals were divided into four groups randomly: control group (C), atherosclerotic plaque group (AP), atherosclerotic plaque with blank vector pEGFP-N1 transfection group (APV), and atherosclerotic plaque with pEGFP-N1-sFlt-1 transfection group (APsFlt-1). The local expression of sFlt-1 protein in target artery was detected by western blotting. The plaque area (PA), plaque circumference (PC), and maximum plaque thickness (MPT) were measured via HE staining. Degree of intra-plaque angiogenesis was evaluated by CD34+ cells immunohistochemistry. As results, we observed that pEGFP-N1-sFlt-1 transfection suppressed the HUVECs proliferation and ability of tube formation, against the effect of VEGF. We obtained higher local expression of sFlt-1 protein in Group APsFlt-1 than that in other groups (P < 0.05). PA, PC, and MPT of plaque in group APsFlt-1 were significantly decreased when compared with other groups (P < 0.05). Amount of annulations surrounded by CD34-positive cells was significantly decreased in pEGFP-N1-sFlt-1 transfection group, which represented decreased level of intra-plaque neovessels formation. The present study confirmed that local gene delivery of sFlt-1 can suppress plaque formation, as one of possible mechanisms, via inhibitive effect on intra atherosclerotic plaque angiogenesis, which hints at the clinical utility of sFlt-1 in atherosclerosis therapy.