Omega 3 Polyunsaturated Fatty Acids Suppress the Development of Aortic Aneurysms Through the Inhibition of Macrophage-Mediated Inflammation

Background: Dietary intake of omega 3 polyunsaturated fatty acids (omega 3-PUFAs) reduces progression of atherosclerosis and prevents future cardiovascular events. Macrophages are key players in the pathogenesis of aortic aneurysm. The effects of omega 3-PUFAs on abdominal aortic aneurysm (AAA) formation and macrophage-mediated inflammation remain unclear. Methods and Results: The AAA model was developed by angiotensin II infusion in apolipoprotein E-deficient mice. Mice were supplemented with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). The development of AAA lesions and macrophage infiltration in the aorta were analyzed. Gene expression of inflammatory markers in aortic tissues and peritoneal macrophages were measured by using quantitative polymerase chain reaction. AAA formation and macrophage infiltration were significantly suppressed after EPA and DHA administration. EPA administration and DHA administration significantly decreased the expression of tumor necrosis factor-a, monocyte chemoattractant protein-1, transforming growth factor-beta, matrix metalloproteinases (MMP)-2, MMP-9, and vascular cell adhesion molecule-1 in the aortas. The expression of arginase 2, which is a marker of pro-inflammatory macrophages, was significantly lower and that of Ym1, which is a marker of anti-inflammatory macrophages, and was significantly higher after EPA and DHA administration. The same trends were observed in peritoneal macrophages after EPA and DHA administration. Conclusions: Dietary intake of EPA and DHA prevented AAA development through the inhibition of aortic and macrophage-mediated inflammation.