Renovascular Hypertension Aggravates Atherosclerosis in Cholesterol-Fed Rabbits.

BACKGROUND: Hypertension is a major risk factor for atherosclerotic disease. However, it is still not clear whether mechanical stress caused by hypertension directly affects the atherosclerotic development in the aorta and coronary arteries.

OBJECTIVES AND METHODS: We generated a hypertensive (HTN) rabbit model by surgical removal of the left kidney and partial ligation of the right renal artery. After a 16-week cholesterol diet, we compared aortic and coronary atherosclerosis of HTN rabbits with those of normotensive rabbits.

RESULTS: Hypertension did not affect lipid and apolipoprotein levels in plasma but led to a 3.0-fold increase in aortic atherosclerosis and a 1.7-fold increase in coronary atherosclerosis compared with control rabbits. Enhanced atherosclerosis in HTN rabbits was caused by significant increases in macrophages and smooth muscle cells in the lesions. Furthermore, oxidized LDL contents in the lesions were significantly increased in HTN rabbits. In addition, HTN rabbits exhibited prominent hyaline arteriolosclerosis in coronary arterioles.

CONCLUSIONS: These results indicate that hyper tension not only enhances atherosclerosis in large arteries including the aorta and coronary arteries but also affects hyaline arteriolosclerosis in small arteries.