BACKGROUND : Diabetes is an independent risk factor in the development of atherosclerosis. Oxidation of low-density lipoprotein is considered to be an important step in the pathogenesis of atherosclerosis. The purpose of the present study was to investigate the occurrence of in vivo LDL oxidation in diabetic patients by measuring antibody against oxidized LDL. METHODS : Plasma samples from 64 NIDDM patients and 30 normal controls were tested for antibody against oxidized LDL by two ELISA methods and for plasma lipid hydroperoxides by the ferrous oxidation with xylenol orange (FOX II) assay. In the first ELISA, antibody levels were estimated as the difference in binding to copperoxidized LDL between untreated plasma and plasma preabsorbed with oxidized LDL. In the second ELISA, antibody levels were estimated as the ratio of IgG binding to copper-oxidized LDL to native LDL. RESULTS : There was no significant difference in levels of antibodies to copper-oxidized LDL between NIDDM patients and normal controls with both ELISA methods. There was also no significant difference in levels of antibodies to copper-oxidized LDL between NIDDM patients with ischemic heart disease (n=24) and NIDDM patients without ischemic heart disease (n=40). Plasma lipid hydroperoxides in the diabetic group were significantly higher than in the control. CONCLUSION : The present study shows that antibodies to copper-oxidized LDL are not significantly raised in our NIDDM patients. Further study to measure antibodies to malondialdehydeLDL would be necessary.
Antibodies ; Atherosclerosis ; Citrus sinensis ; Diabetes Mellitus* ; Diabetes Mellitus, Type 2 ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G ; Lipoproteins* ; Myocardial Ischemia ; Plasma ; Risk Factors