Rimonabant, a Selective Cannabinoid CB1 Receptor Antagonist, Inhibits Atherosclerosis in LDL Receptor–Deficient Mice

Abstract

Objective— The objective of this study was to determine whether the potent selective cannabinoid receptor-1 antagonist rimonabant has antiatherosclerotic properties. Methods and Results— Rimonabant (50 mg/kg/d in the diet) significantly reduced food intake (from 3.35±.04 to 2.80±0.03 g/d), weight gain (from 14.6±0.7 g to −0.6±0.3 g), serum total cholesterol (from 8.39±0.54 to 5.32±0.18 g/L), and atherosclerotic lesion development in the aorta (from 1.7±0.22 to 0.21±0.037 mm 2 ) and aortic sinus (from 101 000±7800 to 27 000±2900 μm 2 ) of LDLR −/− mice fed a Western-type diet for 3 months. Rimonabant also reduced plasma levels of the proinflammatory cytokines MCP-1 and IL12 by 85% ( P <0.05) and 76% ( P <0.05), respectively. Pair-fed animals had reduced weight gain (6.2±0.6 g gain), but developed atherosclerotic lesions which were as large as those of untreated animals, showing that the antiatherosclerotic effect of rimonabant is not related to reduced food intake. Interestingly, rimonabant at a lower dose (30 mg/kg/d in the diet) reduced atherosclerosis development in the aortic sinus (from 121 000±20 000 to 62 000±11 000 μm 2 , 49% reduction, P <0.05), without affecting serum total cholesterol (7.8±0.7 g/L versus 8.1±1.3 g/L in the control group). Rimonabant decreased lipopolysaccharide (LPS)- and IL1β-induced proinflammatory gene expression in mouse peritoneal macrophages in vitro as well as thioglycollate-induced recruitment of macrophages in vivo (10 mg/kg, po bolus). Conclusions— These results show that rimonabant has antiatherosclerotic effects in LDLR −/− mice. These effects are partly unrelated to serum cholesterol modulation and could be related to an antiinflammatory effect.