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Artery stenosis inhibits regression of diet-induced atherosclerosis
Abstract:
Reduction of blood pressure and serum cholesterol levels is associated with reduced risk for the development of arteriosclerotic disease. Experimental studies indicate that reduced cholesterol levels result in arrest or regression of established diet-induced arterial lesions, but the effects of blood pressure reduction on such lesions are not clear. In order to investigate the effects of blood pressure on the regression of established lesions, we induced aortic intimal disease in cynomolgus monkeys by means of an artherogenic diet, produced midthoracic aortic coarctations, and restored the animals to low-cholesterol diets for 6 months. Diet control animals were neither coarctated nor restored to low-cholesterol diets. Animals with severe aortic stenosis and the regression diet had the same degree of abdominal aortic atherosclerosis and mural cholesterol content as diet control animals but esterified cholesterol and collagen content was elevated. Animals with mild coarctation and consuming the regression diet had significantly less abdominal aortic atherosclerosis than the diet control animals or the animals with severe coarctation. Although stenosis prevented the induction of lesions in previous experiments, the present study indicates that it did not reverse or delay progression of previously established lesions. The effect of pressure reduction on atherogenesis, even in the presence of reduced cholesterol levels, may depend on the extent and nature of the underlying lesions.
Insights
Lowering blood pressure may not reverse existing arteriosclerotic disease. Arterial lesions in monkeys showed reduced progression with mild coarctation but not significant regression, suggesting lesion type impacts treatment effectiveness.
Area of Science:
- Cardiovascular Science
- Arteriosclerosis Research
- Animal Models in Atherosclerosis
Background:
- Reduced blood pressure and cholesterol levels are linked to lower arteriosclerotic disease risk.
- While reduced cholesterol can regress arterial lesions, blood pressure reduction's effect remains unclear.
Purpose of the Study:
- To investigate the impact of blood pressure reduction on the regression of established arterial lesions.
- To determine if aortic coarctation influences the regression of diet-induced atherosclerosis.
Main Methods:
- Aortic intimal disease was induced in cynomolgus monkeys using an atherogenic diet.
- Midthoracic aortic coarctations were created, and animals were placed on low-cholesterol diets for 6 months.
- Control groups included animals without coarctation or regression diets.
Main Results:
- Severe coarctation with regression diet showed similar atherosclerosis to controls, but with elevated esterified cholesterol and collagen.
- Mild coarctation with regression diet significantly reduced abdominal aortic atherosclerosis compared to controls and severe coarctation.
- Stenosis did not reverse or delay progression of previously established lesions.
Conclusions:
- Blood pressure reduction's effect on atherogenesis depends on the extent and nature of underlying lesions.
- Mild aortic stenosis combined with a cholesterol-lowering diet can reduce atherosclerosis progression.
- Established arteriosclerotic lesions may not regress significantly with pressure reduction alone.