Studies have been performed on groups of mini-pigs 21-23 months of age, which after 18 months of
hypercholesterolemia (approximately 10 mmol) had developed raised atherosclerotic lesions with high levels of
cholesterol esters, especially in the abdominal aorta and the coronary arteries. If the
hypercholesterolemia was continued for 18 months, no significant change in the
cholesterol ester content in the aorta occurred; in the coronary arteries there was a significant decrease in these older pigs. If the hypercholesterolemic pigs also were treated with
beta-pyridylcarbinol the findings were very similar to the first. When hypercholesterolemic pigs were treated with
clofibrate, or when the hypercholesterolemic diet was replaced with the basal food for 18 months, the plasma
cholesterol level was normalized (approximately 2 mmol) within 1-2 months. The
cholesterol ester content in the thoracic aorta was reduced in both groups but not that in the abdominal aorta.
Clofibrate decreased the
cholesterol ester level in the coronary arteries when compared to the hypercholesterolemic group; the
drug also reduced the free
cholesterol level when compared to the basal group. We suggest that an increased plasma
cholesterol level initiated the development of the atherosclerotic lesions; their later development was only partly dependent on the plasma
cholesterol level.