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, iliac-femoral, 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.