An increase in the EPA/AA ratio is associated with improved arterial stiffness in obese patients with dyslipidemia

Aim: Previous epidemiological studies demonstrated that the ratio of n-6 to n-3 polyunsaturated fatty acids is associated with cardiovascular diseases. We herein investigated whether the beneficial effect of highly purified eicosapentaenoic acid(EPA) on arterial stiffness is associated with changes in the ratio of polyunsaturated fatty acids, such as EPA, docosahexaenoic acid(DHA) and dihomo-γ-linolenic acid (DGLA), relative to arachidonic acid(AA), in obese Japanese patients with dyslipidemia. Methods: The EPA/AA, DHA/AA and DGLA/AA ratios were compared between obese patients with(n=94) and without (n=31) dyslipidemia. Among the former group, 88 patients received either highly purified EPA treatment(1.8g daily, n=45) or treatment without EPA(control, n=43). Results: At baseline, the ratios of DHA/AA and DGLA/AA were significantly(P<0.05) higher in obese patients with dyslipidemia than in those without, while the EPA/AA ratio was similar between patients with and without dyslipidemia. EPA significantly reduced the hemoglobin A1c, total cholesterol, triglycerides, CRP, cardio-ankle vascular index(CAVI) (an index of arterial stiffness) and the DGLA/AA ratio relative to the control at three months after the treatment. On the other hand, EPA significantly increased the adiponectin level and EPA/AA ratio(P<0.05). A multivariate regression analysis revealed that only age, an increase in the EPA/AA ratio and a decrease in the CRP level were significant determinants of a reduction of the CAVI by EPA. Conclusion: These findings suggest that EPA improves the arterial stiffness in association with an increase in the EPA/AA ratio and a decrease in inflammation in obese patients with dyslipidemia.