Effects of oxidative modification of lipoproteins on blood coagulation and fibrinolysis

AIM: To study the effects of oxidative modification lipoproteins on blood coagulation and fibrino-lysis in vitro. METHODS: Normal human plasma VLDL, LDL and HDL, which were isolated by density gradient ultracentrifugation method, were oxidatively modified by Cu²⁺ and HOCl method. N-VLDL, Ox-VLDL, N-LDL, Ox-LDL, N-HDL, Ox-HDL were added to the reaction system which consisted of mixed fresh normal plasma respectively, prothrombin time (PT), activated partial thrombplastin time (APTT), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA) and platelet aggregation were measured according to the direction of the kits. RESULTS: The relative electrophoretic mobility (REM), absorbance at 234nm and TBARS of oxidized VLDL, LDL and HDL mediated by HOCl or Cu²⁺ were significantly higher than that of the control group (P<0.01). N-VLDL, N-LDL and N-HDL had no effect on PT, APTT, t-PA, PAI-1 and platelet aggregation. The PT and APTT of Ox-VLDL, Ox-LDL and Ox-HDL were significantly shorter than that of the control group (P<0.05 and P<0.01). The platelet aggregation of Ox-VLDL, Ox-LDL and Ox-HDL were significantly stronger than that of the control group (P<0.01). The Ox-VLDL and Ox-LDL were higher in t-PA and lower in PAI-1 than that of the control group (P<0.05 and P<0.01), but the Ox-HDL had no influences on t-PA and PAI-1 activity. CONCLUSIONS: N-VLDL, N-LDL and N-HDL have no effects on blood coagulation and fibrinolysis in vitro. Ox-VLDL, Ox-LDL and Ox-HDL enhance blood coagulation and thrombosis. Ox-VLDL and Ox-LDL enhance t-PA activity and decreased PAI-1 activity, but Ox-HDL does not affect the fibrinolysis activity.