Rapid increase of glycosaminoglycans in the aorta of hypercholesterolemic rats; a negative correlation with plasma HDL concentration.

Rats were kept either on a standard laboratory diet or a high cholesterol, olive oil diet for periods ranging from 1 day to 22 weeks. The effect of the high cholesterol, olive oil diet on the concentrations of cholesterol, glycosaminoglycans (GAGs) and collagen in aortic intima-media, were studied and the developing hyperlipidemia was characterized. The concentration of cholesterol in rat aorta was increased after 22 weeks' high cholesterol, olive oil diet, while collagen concentration was not affected. On the contrary, the concentration of aortic sulphated GAGs was significantly increased already after one week's high cholesterol, olive oil diet. The diet increased the formation of a cholesterol-rich very low density lipoprotein (VLDL), decreased high density lipoprotein (HDL)-associated cholesterol and phospholipids, but had virtually no effect on low density lipoprotein (LDL)-lipids. The concentrations of VLDL-cholesterol and -phospholipids showed positive correlations with the concentration of aortic GAGs (r = 0.89 and 0.83, respectively, P less than 0.05 for both). Stronger (negative) correlations were found between aortic GAGs and HDL-cholesterol and -phospholipids (r = 0.94 for both, P less than 0.01) suggesting that HDL may have a role in the control of arterial sulphated GAG concentration.