Effects of two forms of hypertension on atherosclerosis in the hyperlipidemic baboon.

Abstract

We examined the relationship of hypertension and plasma renin activity to atherogenesis in 48 moderately hyperlipidemic (total serum cholesterol was about 200 mg/dl) baboons (Papio sp.). We used renal artery stenosis (two-kidney, one clip model) to produce hypertension associated with elevated plasma renin activity, and used cellophane wrapping of both kidneys (bilateral perinephritis model) to produce hypertension with normal renin activity. Renal artery stenosis and bilateral perinephritis increased both systolic and diastolic blood pressure by about 30 mm Hg. Renal artery stenosis approximately doubled, but bilateral perinephritis did not change plasma renin activity.Both hypertensive groups, to about the same degree, had significantly more extensive atherosclerosis than the control group in the abdominal aorta and brachial, iliacfemoral, and carotid arteries. The effect of hypertension was greatest in the carotid arteries where the extent of atherosclerosis was nearly tripled. Hypertension did not influence lesions in the thoracic aorta.By multiple regression analysis, very low plus low density lipoprotein cholesterol, high density lipoprotein cholesterol, and systolic blood pressure were consistently strong predictive variables for the extent of atherosclerotic lesions. Most of the effects of renal hypertension on atherosclerotic lesions appeared to be accounted for by the increase in blood pressure. In the carotid arteries, however, there was a suggestion of an effect above that due to increased blood pressure. Additional analyses indicated that these treatment effects were associated with serum potassium concentration, plasma renin activity, or other closely related variables. (Arteriosclerosis 5:481-493, September/October 1985)

Hypertension and Endothelial Dysfunction in Apolipoprotein E Knockout Mice

“…exacerbates atherosclerosis in the hyperlipidemic animals. 32,33 Clinical studies have shown that hypertension is associated with increased intima-media thickness and more frequent plaques in extracoronary arteries, more frequent calcifications in coronary arteries, increased wall rigidity in the aorta and peripheral arteries, and impaired endotheliumdependent vasodilation and abnormal blood rheology, which are capable of promoting thrombosis in the background of atherosclerosis. 34 Our finding that 7.5-month-old, but not 6-week-old, Apoe -/-mice exhibited increased arterial pressure is basically consistent with an earlier report demonstrating only a modest increase in blood pressure measured by a tail-cuff method in either restrained or anesthetized mice at 9 weeks of age compared with the controls, which was not statistically significant.…”

Combined antihypertensive and lipid-lowering therapy in experimental glomerulonephritis.

“…On the second postoperative day, all rats were immunized by subcutaneous administration of 20 mg goat -y-globulin in Freund's complete adjuvant. 6 This was followed on the fifth and eighth postoperative days by intravenous injection of goat •y-globulin with activity directed against rat glomerular basement membrane. Four weeks after induction of nephritis, blood samples and 24-hour urine collections were obtained for determination of blood urea nitrogen, cholesterol, triglyceride, and creatinine in the serum and protein and creatinine in the urine.…”

Hyperlipidemic arterial dysfunction.

“…13 We were then able to demonstrate by video-microscopic visualization of skeletal muscle microvessels in situ that arterioles (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) studies in which patients with variant angina were challenged with parasympathetic (methacholine) and sympathetic (epinephrine) agonists. They suggested that enhanced activity of the parasympathetic nervous system was involved in initiating attacks of variant angina.…”