Dietary ω-3 fatty acids and endothelium-dependent responses in porcine cerebral arteries

Purpose: We sought to determine the effect of dietary ?-3 polyunsaturated fatty acids on cerebro vascular endot helium-dependent responses in studies performed on isolated porcine basilar arteries. Methods: Male Yorkshire pigs (6-8 weeks old) were kept for 4 weeks on a standard diet (control group, n = 12) or on chow supplemented with polyunsaturated fatty acids (eicosapentaenoic acid, 3.5 g/day, or docosahexaenoic acid, 1.5 g/day; treated group, n=12). Isometric tension recording of the basilar artery was carried out and responses were compared between the two groups. Results: The regimen resulted in a decrease in the plasma arachidonic acid level and an increase in eicosapentaenoic acid. Endothelium -dependent relaxations induced by bradykinin and adenosine diphos-phate were augmented in the basilar arteries of the treated group. Incubation with indomethacin (10-5 M) prevented the augmentation of the relaxations induced by bradykinin, but not those caused by adenosine diphosphate. The indomethacin-sensitive, endothelium-dependent contractions to arachidonic acid remained comparable in the two groups, indicating that the activity of cyclooxygenase was not affected by the diet. Conclusions: Dietary supplementation with ?-3 poly un saturated fatty acids enhances endothelium-dependent relaxations in the basilar artery by two mechanisms: 1) replacement of endogenous arachidonic acid and suppression of the concomitant release of vasoconstrictor prostaglandins from the endothelium, and 2) enhancement of the release of endot helium-derived relaxing factor.