Effects Of Oxidized Low Density Lipoprotein On Endothelial Progenitor Cells Survival And Function

Backgroud: Postnatal neovascularization is a crucial compensatory response in chronical ischemic diseases. Recently, increasing evidence has indicated that postnatal neovascularization involves the incorporation of endothelial progenitor cell (EPC). Postnatal neovascularization has been shown to be impaired in cardiovascular disease. Furthermore, oxLDL serves as one of the most important predictors of cardiovascular disease.Objectives: To investigate whether oxLDL affectes EPC survival and function, whether oxLDL affects the biology of EPC by an inhibitory effect on endothelial nitric oxide synthase (eNOS) and whether the effect of oxLDL on EPC is mediated by its receptor, lectin-like oxLDL receptor (LOX-1).Methods: CD34~+ cells isolated and enriched from human umbilical cord blood (UCB) by magnetically activated cell sorting (MACS) were plated in fibronectin-coated dishes and cultured in endothelial cell growth medium-2 (EGM-2) supplemented with 50 ng/mL vascular endothelial growth factor (VEGF), 100 ng/mL stem cell growth factor (SCF), 20 ng/mL interleukin (IL-3). After 14 d of culture, EPC was stimulated with different concentrations of oxLDL(10, 25, 50μg/ml) for 48h. Among these EPC, two groups of EPC were preincubated with 10μg/mL LOX-1 monoclonal antibody (LOX-1 mAb), a blocking antibody of LOX-1, or 100μmol/L L-arginine, a precursor of NO, for 24 h and then exposed to 50μg/mL oxLDL for 48 h. Another group of EPC was only treated with 100μmol/L N-nitro-1-arginine methyl ester (L-NAME) or triciribine for 48h. The survival of EPC was examined by AnnexinV/PI binding assay. The ability of EPC migration and in vitro vasculogensis was examined by transwell...