Morphological effects of moderate diet and clofibrate on swine atherosclerosis.

Early proliferative coronary atherosclerosis was produced in swine by feeding them a high-fat, high-cholesterol diet for 17 months, at which time one group of animals was killed (reference group), while the remainder was transferred for 12 months to a moderate diet that resulted in serum cholesterol levels of about 190 mg/100 ml. The moderate diet only did not decrease the size of coronary lesions, but prevented their progression. The addition of clofibrate therapy caused regression that involved a significant decrease in size, gross sudanophilia, and extent of calcification and the disappearance of foam-cell lesions. Resultant serum cholesterol levels appear to be more important than the amount of dietary cholesterol in the progression, prevention, and regression of swine coronary atherosclerosis.