Glycation of high-density lipoprotein triggers oxidative stress and promotes the proliferation and migration of vascular smooth muscle cells

BACKGROUND: In type 2 diabetes mellitus (T2DM), high-density lipoprotein (HDL) impairs its anti-atherogenic properties and even develops to a pro-inflammatory and pro-atherogenic phenotype because of abnormal compositions and modifications. In this study, we examined the effects and the related mechanisms of glycation of HDL on the proliferation and migration of vascular smooth muscle cells (VSMCs). METHODS & RESULTS: Glycated HDL (G-HDL) was modified with D-glucose (25 mmol/L) in vitro. Diabetic HDL (D-HDL) was isolated from T2DM patients. Rat VSMCs were isolated from the thoracic aortas. Human VSMCs were obtained from ScienCell Research Laboratories. Alpha-actin was detected through immunofluorescence. VSMC proliferation was assayed by Cell Count. VSMC migration was determined by transwell chamber and scratch-wound assay. Intracellular reactive oxygen species (ROS) was detected based on ROS-mediated 2′,7′-dichlorofluorescein (DCFH-DA) fluorescence. Compared to native HDL (N-HDL), G-HDL remarkably promoted VSMC proliferation and migration in the dose and time-dependent manners. In addition, G-HDL enhanced ROS generation in VSMCs. However, the ROS scavenger, N-acetylcysteine, efficiently decreased ROS production and subsequently inhibited the proliferation of VSMCs induced by G-HDL. Similarly, D-HDL from T2DM patients also promoted ROS release and VSMC proliferation and migration. CONCLUSIONS: HDL either glycated in vitro or isolated from T2DM patients triggered VSMC proliferation, migration, and oxidative stress. These results might partly interpret the higher morbidity of cardiovascular disease in T2DM patients.