Antibodies to oxidized low-density lipoproteins and angiographically assessed coronary artery disease in white patients

Background- Low- density lipoprotein (LDL) can be oxidatively modified by reactive oxygen species, thus generating oxLDL. The latter induce formation of specific antibodies (oxLDLAb), which are detectable in patients with atherosclerosis, in which they might play a pathogenic or a protective role. Thus, we aimed to investigate the association of antibodies with oxidized LDLs (oxLDL) (oxLDLAbs) with coronary artery disease (CAD) and acute coronary syndromes. Methods and Results-In a cross-sectional study of 529 consecutive patients undergoing quantitative coronary angiography for suspected CAD, we measured the titer of IgG oxLDLAbs by ELISA. With regression analysis techniques, we also investigated the determinants of oxLDLAb titer and the association of oxLDLAbs with CAD severity. We found no significant differences of oxLDLAb titer between groups of patients without and with different CAD severity. The oxLDLAb titer was 18.6 enzyme units (EU) (11.5 to 25.7 EU/mL) (mean, 95% CI) in patients without CAD; 16.8 EU (9.6 to 24.2 EU) in patients with stenosis <50%; and 19.9 EU (15 to 24.8 EU), 17.2 (13.8 to 20.6 EU), and 14.7 EU (12.1 to 17.3 EU) in those with in 1-, 2-, or 3-vessel >= 50% stenosis, respectively. Similarly, no differences of oxLDLAb titer between patients without and with acute coronary syndrome were found. The oxLDLAb titer correlated weakly with aging and with serum total, LDL, and HDL cholesterol and plasma homocysteine levels; however, only age and HDL cholesterol remained significant predictors of the oxLDLAb titer at a stepwise regression analysis. Conclusions-The results of this study, which was adequately powered from the statistical standpoint, provided no evidence for an association of IgG oxLDLAb titer with angiographically assessed CAD in whites.