Changes in the phospholipid composition of the arterial cell can result insevere atherosclerotic lesions

The oxysterol concentration in the plasma and the phospholipid composition of vascular tissue obtained by coronary artery bypass grafting (CABG) were compared with plasma and vascular tissue from age and sex matched controls. The Plasma from CABG patients had a higher concentration of oxysterols tha n was present in the controls. Human endothelial cells were cultured for 72 hours in a medium containing plasma obtained from CABG patients, from cont rols or from the same controls to which 5 oxysterols were added to make the total oxysterol level equivalent to that in the CABG plasma and then pulse d with calcium (Ca-45(2+)) for one fir. A significantly higher influx of Ca -45(2+) was noted in the endothelial cells cultured in the plasma obtained from CABG patients and from the controls with 5 added oxysterols, but not i n those cultured without added oxysterols indicating that oxysterols increa sed calcium influx into endothelial cells. A phospholipid analysis indicate d that the arterial tissue from CABG patients had 48.2% sphingomyelin in it s phospholipid fraction compared to 10% in arterial tissue from umbilical c ords. The saphenous vein obtained during CABG surgery from the same patient had only 24% sphingomyelin in its phospholipid fraction and unlike the cor onary arteries had no atherosclerotic lesions. The higher level of oxystero l in the plasma of patients suffering from severe atherosclerosis could inc rease the concentration of sphingomyelin in the arterial cell membrane and thereby increase calcium influx required for producing the calcific type VI I lesions in the coronary arteries. (C) 2001 Elsevier Science Inc. All righ ts reserved.