Increased transfer of cholesteryl esters from high density lipoproteins to low density and very low density lipoproteins in patients with angiographic evidence of coronary artery disease

Abstract

Cholesterol esterification, transfer of cholesteryl esters from high density lipoproteins to very low density and low density lipoproteins (VLDL/LDL) and the composition of lipoproteins isolated by density gradient ultracentrifugation have been investigated in 18 men with angiographic evidence of severe coronary artery disease and in 27 healthy men without coronary artery disease. Patients had significantly higher serum cholesterol ( P < 0.001), serum triglycerides ( P < 0.02) and lower high density lipoprotein cholesterol (HDL) ( P < 0.04) compared with healthy men. The transfer of cholesteryl ester from HDL to VLDL and LDL was 27.8 ± 12.2 nmol/ml per h (mean ± S.D.) in patients and was significantly higher than the value of 17.8 ± 6.5 nmol/ml per h obtained in healthy men (P < 0.003) or 17.1 ± 7.6 nmol/ml per h) in 16 controls ( P < 0.03) with similar serum cholesterol and triglyceride concentrations. Lipoprotein protein concentrations were significantly higher in LDL ( P < 0.05) and small VLDL ( P < 0.01) in patients. In addition, patient LDL and large VLDL contained more free cholesterol than matched controls ( P < 0.01, P < 0.05, respectively). This was reflected in the increased free cholesterol/phospholipid ratio (a measure of lipoprotein surface composition) in LDL ( P < 0.002). These findings indicate that patients with established coronary artery disease have increased transfer of cholesteryl ester from HDL to VLDL and LDL, which is independent of serum triglyceride concentrations. This increased transfer of cholesteryl ester may be a result of the increased free cholesterol content of very low density lipoproteins.