Incremental replacement of saturated fats by n-3 fatty acids in high-fat, high-cholesterol diets reduces elevated plasma lipid levels and arterial lipoprotein lipase, macrophages and atherosclerosis in LDLR-/- mice

Abstract

Objective: Effects of progressive substitution of dietary n-3 fatty acids (FA) for saturated FA (SAT) on modulating risk factors for atherosclerosis have not been fully defined. Our previous reports demonstrate that SAT increased, but n-3 FA decreased, arterial lipoprotein lipase (LpL) levels and arterial LDL-cholesterol deposition early in atherogenesis. We now questioned whether incremental increases in dietary n-3 FA can counteract SAT-induced pro-atherogenic effects in atherosclerosis-prone LDL-receptor knockout (LDLR-/-) mice and have identified contributing mechanisms. Methods and results: Mice were fed chow or high-fat diets enriched in SAT, n-3, or a combination of both SAT and n-3 in ratios of 3:1 (S:. n-3 3:1) or 1:1 (S:. n-3 1:1). Each diet resulted in the expected changes in fatty acid composition in blood and aorta for each feeding group. SAT-fed mice became hyperlipidemic. By contrast, n-3 inclusion decreased plasma lipid levels, especially cholesterol. Arterial LpL and m