Effects of dietary fish oil and butterfat on serum lipids and monocyte and platelet interactions with aortic endothelial cells.

We studied effects of dietary lipids on some of the initial events in atherogenesis. Adult swine were fed low fat/low cholesterol diets, then challenged with a high cholesterol (1%, w/w) diet supplemented with 11.5% (w/w) butterfat (BF) or MaxEPA fish oil (FO). Serum lipids and monocyte and platelet adhesion to porcine aortic endothelial cells in vitro were measured during feeding of the low fat diet and at 1, 2, and 5 weeks after the dietary challenge. Total cholesterol increased significantly in animals fed the BF and FO diets, but there was no difference between the groups. Animals fed FO had total cholesterol/high-density lipoprotein cholesterol values twice those fed BF (P less than 0.01). After 2 weeks on the hypercholesterolemic diet, monocyte adhesion to endothelial cells increased in swine fed FO by 123% above those fed a low fat diet, and adhesion values remained elevated (56% above baseline value) after 5 weeks. Monocytes from swine fed BF showed increased adhesion by 87, 53, and 14% above those fed the low fat diet at 1, 2, and 5 weeks respectively. Platelet adhesion to endothelial cells decreased (P less than 0.05) after diet change and remained low. Adhesion of platelets from swine fed FO was significantly lower than those fed BF at 1 and cholesterol profile and greater monocyte adhesion to endothelial cells, conditions which in vivo may promote lesion initiation.