HIGHLY PURIFIED EICOSAPENTAENOIC ACID ATTENUATES TISSUE-DAMAGE IN EXPERIMENTAL MYOCARDIAL-INFARCTION

We examined the effects of dietary supplementation with eicosapentaeno ic acid (EPA) on experimental myocardial infarction in dogs. Twenty-fi ve dogs were fed standard diets, 10 of which were supplemented with EP A-ester (100 mg/kg body weight/day) for 8 weeks, while 15 served as co ntrols. After ingesting EPA for 8 weeks, the ratio of EPA to arachidon ic acid (AA) in platelet cell membranes significantly increased (from 0.033 to 0.105; p<0.01). The chemotactic response of neutrophils to le ukotriene B4 (LTB4) was reduced in the EPA group (34% reduction at 10( -6) M LTB4, p<0.01). Also in the EPA group, the amount of 12-hydroxyei cosatetraenoic acid, one of the chemotactic products of AA in infarcte d myocardium, was reduced to 40% (p<0.05). EPA treatment resulted in s ignificant reduction in the ultimate size of the infarcted area. Contr actile function of infarcted myocardium was well-preserved in the EPA group. Myeloperoxidase activity, an indication of the infiltration of neutrophils into the infarcted myocardium, was less in the EPA group t han in the controls (0.68+/-0.25 U/0.1 gr. vs 1.22+/-0.55 U/0.1 gr., p <0.05). Therefore, we conclude that dietary supplementation with EPA a ttenuates ischemic myocardial damage through inhibition of neutrophili c infiltration into the infarcted myocardium.