Improvement of endothelial function
Long-term treatment with fish oils augments endothelium-dependent relaxation of normal porcine coronary arteries,25 for which EPA, a major omega-3 fatty acids of fish oils, is responsible for the augmentation.26 This augmenting effect of EPA was also noted in porcine coronary microvessels.27 Long-term treatment with fish oils improves endothelium-dependent relaxation of hypercholesterolaemic and atherosclerotic porcine coronary arteries28 and femoral veins.29 Eicosapentaenoic acid augments endothelium-dependent relaxation by NO as well as that by endothelium-derived hyperpolarizing factor.30 Docosahexaenoic acid alters caveolae microenvironment not only by modifying membrane lipid composition, but also by changing distribution of major structural proteins, eventually increasing eNOS activity in human umbilical vein endothelial cells.31 Nitric oxide also inhibits platelet aggregation and adhesion, leucocytes adhesion, and smooth muscle cell proliferation. In addition, in endothelial cells, co-incubation with DHA following challenge with interleukin (IL)-1, IL-4, tumour necrosis-α, or lipopolysaccharide decreases expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and E-selectin, and secretion of IL-6 and IL-8.32