Abstract 5576: Nitro-fatty Acids Reduce Atherosclerosis in ApoE Deficient Mice

Abstract

Objective Inflammatory processes and foam cell formation are key determinants in atherosclerosis. Electrophilic nitro-fatty acid derivatives, endogenously generated by nitric oxide- and nitrite-dependent redox reactions, mediate potent anti-inflammatory signaling actions via both receptor-dependent pathways and posttranslational modification. In vitro evidence supports that nitro-fatty acids inhibit vascular inflammatory signaling, but their in vivo actions in murine models of vascular disease remains to be elucidated. Methods and Results Herein, we demonstrate that subcutaneous administration of nitro-oleic acid (OA-NO 2 ) to apolipoprotein E deficient mice as compared to vehicle or oleic acid (OA) potently reduced atherosclerotic lesion formation in the aortic valve area (lesion area OA-NO 2 : 0.37±0.03 mm 2 ; vehicle: 0.54±0.02 mm 2 ; OA: 0.57±0.01 mm 2 ; p<0.001) as well as in the entire aorta (% of atherosclerotic surface area: OA-NO 2 : 11.3±2.5%; vehicle: 18.5±2.6%; OA: 21.1±3.5%; p<0.001). Immunostaining and gene expression analyses revealed that OA-NO 2 significantly inhibited adhesion molecule expression (VCAM and ICAM) and decreased infiltration of inflammatory cells (% of monocyte/macrophage positive area: OA-NO 2 : 23.9±4.3%; vehicle: 48.0±2.0%; OA: 45.7±1.5%; p<0.001; number of neutrophils/field: OA-NO 2 : 10.8±4.8; vehicle: 45.3±3.9; OA: 41.5±3.4; p<0.001). Both in vitro and in vivo models showed that OA-NO 2 reduced foam cell formation by attenuating oxidized LDL induced phosphorylation of signal transducer and activator of transcription-1 (STAT-1), a transcription factor recently linked to foam cell formation in atherosclerotic plaques. In addition, atherosclerotic lesions of OA-NO 2 -treated mice had a higher content of collagen (% of trichrome positive area: OA-NO 2 : 34.3±2.6%; vehicle: 18.3±2.1%; OA: 20.5±2.7%; p<0.001) and α -smooth muscle actin (% of α -SMA positive area: OA-NO 2 : 24.0±3.0%; vehicle: 11.4±0.7%; OA: 11.9±0.6%; p<0.001), suggesting greater plaque stability. Nitro-fatty acids did not influence metabolic profile. Conclusions These results reveal a promising therapeutic benefit in the treatment or prevention of atherosclerosis by supplementing endogenously occurring nitro-fatty acid.