Eicosapentaenoic acid and docosahexaenoic acid block serotonin-induced smooth muscle cell proliferation

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) present in fish oils have been ascribed as having significant antithrombotic and antiathero sclerotic effects. Vascular smooth muscle cell (SMC) proliferation plays an important role in the pathogenesis of atherosclerosis and restenosis. Rece nt studies have indicated that serotonin at concentrations present at sites of vascular injury stimulates SMC proliferation and may contribute to the restenotic process. In the present study we demonstrate that among the fatt y acids tested, only EPA and DHA could block the mitogenic effect of seroto nin on vascular SMC. Further, when added together these fatty acids act syn ergistically in blocking the mitogenic effect of serotonin. EPA and DHA blo cked the 5HT-induced increase in the 5-HT2 receptor mRNA. This antimitogeni c effect of EPA and DHA may partially explain some of the beneficial effect s of fish oils.