High K Diets Markedly Reduce Atherosclerotic Cholesterol Ester Deposition in Aortas of Rats With Hypercholesterolemia and Hypertension

Abstract

High K diets prevent hypertensive endothelial injury and intimal thickening. Cholesterol esters often deposit during hypercholesterolemia. Would a high K diet influence cholesterol ester deposits? In a normal rat on a normal diet, no cholesterol esters are detected in the aorta. Stroke prone SHR rats were fed for 3 months a basic diet containing 4% cholesterol, 14% coconut oil and 7% NaCl. One group of 13 rats had normal (.5%) K in the diet. Another group of 10 rats ate high (2.1%) K. Mean intraarterial blood pressures averaged 165 mm Hg in the normal K group and 161 mm Hg in the high K group (P = NS). The serum cholesterol averaged 229 mg/dL in the normal K group and 214 in the high K group (P = NS). Total aortic cholesterol esters per rat involving 16 and 18 carbon chain fatty acids averaged 187 micrograms in normal K v 68 micrograms in high K, measured by gas chromatography. These were the main esters; other esters were negligible. Thus high K reduced cholesterol ester deposits by 64% (P less than .0003), even though blood pressure and cholesterol levels were quite similar in the two groups. Both high cholesterol and high BP injure endothelial cells and increase invasion of macrophages and vascular smooth muscle cells into the intima and increase endothelial permeability to proteins. With high plasma cholesterol, these processes lead to atherosclerosis with cholesterol ester deposition. The high K diet, by protecting endothelial cells, can greatly decrease this cholesterol ester deposition. This effect could possible be useful for preventing atherosclerotic complications such as heart attacks in human hypertension.