Circulating oxidized low density lipoprotein, autoantibodies against them and homocysteine serum levels in diagnosis and estimation of severity of coronary artery disease

The oxidative hypothesis of atherosclerosis proposes that oxidative modification of low density lipoprotein (LDL) plays a critical role in atherogenesis. The evaluation of LDL oxidation in vivo is therefore very important. However, data concerning the evaluation of the above biochemical marker is very limited in clinical practice. This study was conducted to test the hypothesis that plasma levels of ox-LDL reflect atherosclerosis and determine the clinical significance in the measurement of circulating ox-LDL and autoantibodies against them as well as their correlation with homocysteine and lipid parameters in the diagnosis and severity of coronary heart disease. A total of 273 individuals were examined: 41 suffering from unstable angina pectoris (UAP), 62 from stable angina pectoris (SAP) and 170 healthy control subjects. We used a sensitive method for detecting ox-LDL that is based on a direct sandwich technique (ELISA) in which two monoclonal antibodies are directed against separate antigenic determinants on the oxidized apolipoprotein-B molecule along with another enzyme immunoassay designed to determine human antibodies to oxidized LDL (anti-oxLDL) directly in serum. Total homocysteine (HCY) was evaluated by means of a fully automated fluorescence polarization immunoassay. Patients with UAP exhibited marked elevations in oxLDL levels as compared to patients with SAP (161.2±28.4 vs. 119.2±26.6, p