Effect of Low-Dose Aspirin on Vascular Inflammation, Plaque Stability, and Atherogenesis in Low-Density Lipoprotein Receptor–Deficient Mice

Background—Atherosclerosis is a complex vascular inflammatory disease. Low-dose aspirin is a mainstay in the prevention of vascular complications of atherosclerosis. We wished to determine the effect of low-dose aspirin on vascular inflammation, plaque composition, and atherogenesis in LDL receptor–deficient mice fed a high fat diet. Methods and Results—In LDL receptor–deficient mice fed a high fat diet compared with control mice, low-dose aspirin induced a significant decrease in circulating levels and vascular formation of soluble intercellular molecule-1, monocyte chemoattractant protein-1, tumor necrosis factor-&agr;, interleukin-12p 40, without affecting lipid levels. This was associated with significant reduction of the nuclear factor &kgr;B activity in the aorta. Low-dose aspirin also significantly reduced the extent of atherosclerosis. Finally, aortic vascular lesions of the aspirin-treated animals showed 57% reduction (P <0.05) in the amount of macrophage cells, 77% increase in smooth muscle cells (P <0.05), and 23% increase in collagen (P <0.05). Conclusions—Our results suggest that in murine atherosclerosis, low-dose aspirin suppresses vascular inflammation and increases the stability of atherosclerotic plaques, both of which, together with its antiplatelet activity, contribute to its antiatherogenic effect. We conclude that low-dose aspirin might be rationally evaluated in the progression and evolution of human atherosclerotic plaque.