CORRELATION BETWEEN LAG TIME OF LDL TO IN VITRO OXIDATION AND IN VIVO OXIDIZED LDL IN THE PATIENTS WITH CORONARY ARTERY DISEASE

Abstract    BACKGROUND: The oxidative modification of low density lipoprotein (LDL) is believed to play an important role in the development of atherosclerosis. Thus, measurement of plasma oxidized LDL (OX-LDL) is essential for atherosclerotic diseases, for investigating its relevance to atherosclerotic diseases. We aimed to assess the oxidized LDL in patients with coronary artery disease and correlation between serum oxidized low density lipoprotein and in vitro susceptibility of LDL to oxidation.    METHODS: Subjects of the study were selected from patients who undergone angiography (۴۲ patients with coronary artery disease and ۴۰ controls without any evidence of CAD). The susceptibility of LDL to in vitro oxidation was assessed with the addition of a Cuso۴ solution. The lag time, propagation rate and maximal diene calculated from the oxidation curve. Biochemical factors (FBS, total cholesterol, TG, LDL, and HDL) were measured in these subjects. SPSS version ۱۵.۵ was used to analyze the data, P- value under ۰.۰۵ was considered to be significant.    RESULTS: The results indicated that the serum OX-LDL concentration was significantly elevated in CAD patients and the lag time was significantly shorter than controls (P < ۰.۰۵). These results clearly confirm that LDL from persons with CAD is more susceptible to oxidative modification in vitro than LDL from healthy subjects. The other measured biochemical factors were not significantly different between CAD patients and controls (P > ۰.۰۵). Correlation between serum OX-LDL and susceptibility of LDL to in vitro oxidation did not show significant association (P > ۰.۰۵).     CONCLUSION: our findings suggest that a high OX-LDL concentration and a short LDL oxidation lag time might be independent risk factors for CAD.      Keywords: OX-LDL; Lag time; Maximal Diene; Propagation Rate; Susceptibility.