Positive correlation between in vivo oxidized LDL and LDL immune complexes

Objectives: To investigate the possible relationship between oxidized low-density lipoprotein (ox-LDL) and LDL immune complexes (IC). Methods: Both LDL-IC and ox-LDL were detected by sandwich ELISA. The levels were also studied in 60 patients with coronary heart disease (CHD) and 50 control subjects. Results: Compared to controls, both the plasma ox-LDL concentrations (595.5 ± 194.8 vs. 440.3 ± 175.0 μg/l, P< 0.001) and LDL-IC levels (2.74 ± 0.73 vs. 1.38 ± 0.78 AU, P< 0.001) in the patients with CHD were significantly increased. The relationships between LDL-IC, ox-LDL levels, and other lipid parameters in all the studied subjects (n = 100) were analyzed. LDL-IC levels were positively correlated with TC, TG, LDL-C, lipoprotein(a) [Lp(a)], and apolipoprotein B (apoB) concentration, while negatively correlated with apoA1 concentration, respectively. Similarly, ox-LDL levels were also found positively correlated with TC, LDL-C, and apoB concentrations, respectively. Furthermore, a significantly positive correlation between ox-LDL and LDL-IC levels was found (r = 0.313, P< 0.005). Conclusion: In vivo oxidized LDL positively correlates with circulating levels of LDL immune complexes.