A study of atherosclerotic lesion development in the injured pulmonary arteries of dogs with induced hyperlipemia.
Studies of experimental atherosclerosis in the dog demonstrate that many months at plasma cholesterol concentrations greater than 750 mg/dl are required to produce lipid containing atherosclerotic lesions. Since it has been recognized for many years that vascular injury in combination with hyperlipemia will result in rapid formation of atherosclerotic lesions, we attempted to combine vascular injury with hyperlipemia as a means of accelerating this process in the dog. Injury was produced in pulmonary arteries with experimental Dirofilaria immitis (DI or heartworm) infection. This filarial parasite produces characteristic lipid-free lesions containing smooth muscle cells and occasional monocytes and collagen. Plasma cholesterol was increased by feeding 10 dogs an essential fatty acid-deficient diet (EFAD) for 90 days. Five of the EFAD dogs were infected with 30 to 31 adult DI worms to produce pulmonary artery injury. The remaining 5 EFAD dogs were not subjected to any form of vascular injury. An additional 5 control dogs were not subjected to vascular injury nor to the EFAD diet. The arteries of dogs infected with DI developed myointimal proliferative lesions which contained smooth muscle cells and macrophages. In addition, the EFAD diet produced significant elevations in LDL but not VLDL plasma cholesterol in all 10 dogs fed the diet. However, the plasma cholesterol was less than 750 mg/dl in all EFAD-fed dogs. Although smooth muscle cells and macrophages in the pulmonary arteries of DI-infected dogs were focal points for lipid accumulation, cholesterol content of these injured arteries was not increased compared to noninjured EFAD dogs. The results suggest that even severe vascular injury does not reduce the threshold of 750 mg/dl required to produce significant lipid accumulation in canine arteries.
D000818:Animals; D001161:Arteriosclerosis / Q000378:metabolism / Q000473:pathology*; D002784:Cholesterol / Q000097:blood; D004075:Diglycerides / Q000378:metabolism; D004184:Dirofilariasis / Q000473:pathology; D004285:Dogs; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D006949:Hyperlipidemias / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011651:Pulmonary Artery / Q000293:injuries* / Q000473:pathology; D014280:Triglycerides / Q000378:metabolism
D004075:Diglycerides; D005230:Fatty Acids, Nonesterified; D009829:Oleic Acids; D010743:Phospholipids; D014280:Triglycerides; D019301:Oleic Acid; D002784:Cholesterol