Diabetes-Induced Accelerated Atherosclerosis in Swine
- 1Department of Pathology, Medical College of Georgia, Augusta, Georgia
- 2Gonda Diabetes Center, Beckman Research Institute of the City of Hope, Duarte, California
- 3Division of Endocrinology and Metabolism, University of Virginia Health Science Center, Charlottesville, Virginia
Patients with diabetes are at higher risk for atherosclerotic disease than nondiabetic individuals with other comparable risk factors. Studies examining mechanisms underlying diabetes-accelerated atherosclerosis have been limited by the lack of suitable humanoid animal models. In this study, diabetes was superimposed on a well-characterized swine model of atherosclerosis by injection of the β-cell cytotoxin streptozotocin (STZ), resulting in a >80% reduction in β-cells and an increase in plasma glucose to diabetic levels. Animals were maintained without exogenous insulin for up to 48 weeks. Plasma glucose and cholesterol levels and lesion extent and severity were quantified in swine with diabetes and hyperlipemia alone and in combination compared with controls. Diabetes had no effect on plasma cholesterol levels, but diabetic/hyperlipemic (D-HL) swine developed hypertriglyceridemia and showed a doubling in aortic sudanophilia over nondiabetic/hyperlipemic (N-HL) swine as early as 12 weeks (47.25 ± 4.5 vs. 24.0 ± 4.6%). At 20 weeks, coronary artery stenosis was significantly greater in D-HL than in N-HL animals (86 ± 10 vs. 46 ± 8%). Coronary lesions predominantly arose in the first 2–3 cm of the vessels and displayed humanoid morphology. Aortic lesions in D-HL swine had double the cholesterol content of those in N-HL swine, and incorporation of oleate into cholesteryl ester was significantly greater in grossly normal aortic areas of D-HL swine compared with N-HL and was attributed to similar elevated incorporation in monocytes. This large study demonstrates that a model of diabetes with humanoid characteristics, including hypertriglyceridemia and severe, accelerated atherosclerosis can be reproducibly induced and maintained in swine. This model should potentially be of great value in elucidating mechanisms underlying the accelerated atherosclerosis seen in human diabetic individuals.
Address correspondence and reprint requests to Ross G. Gerrity, Department of Pathology, BF 152, Medical College of Georgia, 1120 15th St., Augusta, GA 30912. E-mail:.
Received for publication 1 November 2000 and accepted in revised form 4 April 2001.
ACAT, acyl-CoA-cholesterol acyltransferase; D-HL, diabetic/hyperlipemic; D-NL, diabetic-normolipemic; N-HL, nondiabetic/hyperlipemic; N-NL, nondiabetic-normolipemic; PBS, phosphate-buffered saline; STZ, streptozotocin.