Objective: Recent studies have suggested that circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) is a useful marker for the identification of patients with coronary artery disease (CAD). However, the role of MDA-LDL in atherogenic mechanisms has not yet been fully determined.
Method and results: We investigated lipoprotein profiles measured by nuclear magnetic resonance (NMR) spectroscopy and circulating MDA-LDL levels measured by ELISA in 25 male patients with CAD and 15 age-matched male controls. We selected subjects who had a serum LDL cholesterol<160 mg/dL. The MDA-LDL levels were significantly higher in the CAD group than in the control group (P=0.01) even though there was no significant difference in the LDL cholesterol levels between the two groups. NMR analysis demonstrated that the MDA-LDL levels were positively correlated with large and intermediate very low-density lipoprotein triglyceride and LDL particle concentrations, and negatively correlated with LDL diameter and large high-density lipoprotein cholesterol. The MDA-LDL levels were negatively correlated with flow-mediated dilatation of the brachial artery.
Conclusions: The high concentrations of circulating MDA-LDL derived from the atherogenic lipoprotein profiles, which induce the exaggerated production of small dense LDL. The circulating MDA-LDL may impair endothelial function and play an important role in the pathogenesis of atherosclerosis.