Regulation of platelet adhesion by oxidized lipoproteins and oxidized phospholipids

Activated platelets adhere to the endothelium and release vasoactive mediators which induce vasoconstriction and remodeling of the vessel wall. The influence of native and ex vivo oxidized lipoproteins enriched with oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (ox-PAPC), the major lipid responsible for the biological activity of minimally oxidized LDL (mm-LDL), on platelet adhesion, membrane receptor expression and aggregation was studied. Influence of native and oxidized lipoproteins (5-100 microg protein/ml); ox-PAPC (0.5-50 microg/ml); ADP (1-10 microM) as well as the specific phosphatase 1 and 2A inhibitor okadaic acid (3-10 microM) on platelet adhesion, receptor expression and aggregation was measured. Platelets adhered to all the classes of lipoproteins immobilized in plastic microtiter wells (native lipoproteins: HDL