Abstract 16486: Omega-3 Polyunsaturated Fatty Acids Suppresses Development of Abdominal Aortic Aneurysm in Apoe-deficient Mice by Shifting the Balance of Macrophages From M1 to M2
Background: Dietary intake of omega-3 polyunsaturated fatty acids (ω3-PUFAs) reduces initiation and progression of atherosclerosis and prevents cardiovascular events. Macrophages have heterogeneous sub-populations such as classically activated macrophages (M1) and alternatively activated macrophages (M2), which relate to anti-inflammatory effect. Eicosapentaenoic acid (EPA) may switch the balance of macrophages from M1 to M2 in adipose tissue. However, the effects of ω3-PUFAs on abdominal aortic aneurysm (AAA) formation and M1/M2 balance are unclear.
Purpose: We assessed the effect of ω3-PUFAs on AAA formation and M1/M2 balance in an AAA murine model.
Methods: The model was developed by osmotic pump infusion of angiotensin II (AngII) for 4 weeks (weeks 12-16) in apoE-deficient mice. The mice were divided into the following 4 groups: Control group, daily saline infusion; AngII group, daily AngII infusion; EPA group, daily oral intake of 5% w/w EPA from weeks 10-16 and daily AngII infusion, and docosahexaenoic acid (DHA) group, daily oral intake of 5% w/w DHA from weeks 10-16 and AngII infusion.
Results: There were no significant differences in the baseline characteristics among the 4 groups. Incidence of AAA formation in the EPA and DHA groups was significantly suppressed compared with those of the AngII group. (EPA, 5.9%; DHA, 0%; AngII, 55.6%; EAP vs. AII, P<0.01; DHA vs. AII, P<0.01). In the EPA and DHA groups, expressions of TNF-α, MCP-1, TGF-β, IL-1β and MMP-2 were lower and the macrophage invasive aortic area was smaller than those in the AngII group. Aortic expression of arginase-2, which is specific for pro-inflammatory M1 macrophages, was significantly lower and that of Ym1, which is specific to anti-inflammatory M2 macrophages, was significantly higher in the EPA and DHA groups than in the AngII group.
Conclusion: Dietary intake of EPA and DHA suppressed development of AAA formation via an anti-inflammatory effect, especially shifting from M1 to M2, suggesting that ω3-PUFAs may beneficial for preventing AAA formation via changing the nature of macrophage.
- © 2013 by American Heart Association, Inc.