Inhibition of Glycosphingolipid Synthesis Ameliorates Atherosclerosis and Arterial Stiffness in Apolipoprotein E −/− Mice and Rabbits Fed a High-Fat and -Cholesterol Diet

Abstract

Background— Glycosphingolipids, integral components of the cell membrane, have been shown to serve as messengers, transducing growth factor–initiated phenotypes. Here, we have examined whether inhibition of glycosphingolipid synthesis could ameliorate atherosclerosis and arterial stiffness in transgenic mice and rabbits. Methods and Results— Apolipoprotein E −/− mice (12 weeks of age; n=6) were fed regular chow or a Western diet (1.25% cholesterol, 2% fat). Mice were fed 5 or 10 mg/kg of an inhibitor of glycosphingolipid synthesis, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), solubilized in vehicle (5% Tween-80 in PBS); the placebo group received vehicle only. At 20 and 36 weeks of age, serial echocardiography was performed to measure aortic intima-media thickening. Aortic pulse-wave velocity measured vascular stiffness. Feeding mice a Western diet markedly increased aortic pulse-wave velocity, intima-media thickening, oxidized low-density lipoprotein, Ca 2+ deposits, and glucosylceramide and lactosylceramide synthase activity. These were dose-dependently decreased by feeding D-PDMP. In liver, D-PDMP decreased cholesterol and triglyceride levels by raising the expression of SREBP2, low-density lipoprotein receptor, HMGCo-A reductase, and the cholesterol efflux genes (eg, ABCG5 , ABCG8 ). D-PDMP affected very-low-density lipoprotein catabolism by increasing the gene expression for lipoprotein lipase and very-low-density lipoprotein receptor. Rabbits fed a Western diet for 90 days had extensive atherosclerosis accompanied by a 17.5-fold increase in total cholesterol levels and a 3-fold increase in lactosylceramide levels. This was completely prevented by feeding D-PDMP. Conclusions— Inhibition of glycosphingolipid synthesis ameliorates atherosclerosis and arterial stiffness in apolipoprotein E −/− mice and rabbits. Thus, inhibition of glycosphingolipid synthesis may be a novel approach to ameliorate atherosclerosis and arterial stiffness.