Aortic atherosclerosis of turkeys induced by feeding of cholesterol.

Summary Aortic atherosclerosis was induced by feeding turkeys 2% cholesterol from 6–14, 24, 30 and 32 weeks of age. Simple, intermediate and advanced stages of aortic atherosclerosis, resulting from feeding cholesterol for the 4 different time intervals, were studied by histologic and electron microscopic techniques. The simplest lesion was characterized by lipid vacuoles in the aortic endothelium, non-membrane bound lipid between cells in the plaque, widening of the extracellular spaces, and fraying of basement membranes of modified smooth muscle cells. An intermediate lesion contained foam cells and necrotic modified smooth muscle cells widely separated by fibrillar material and pools of lipid which appeared to be in the process of crystallization. The advanced atherosclerotic lesions contained foam cells. Many of these cells were necrotic, and some were binucleated. Cholesterol and mineral were present in foam cells as well as in the extracellular spaces. Fibrillar-flocculent material was also present in these spaces. The origin of foam cells and fibrillar-flocculent material in the advanced atheroma is also discussed.