Association of Serum Oxidized Lipoprotein(a) Concentration with Coronary Artery Disease: Potential Role of Oxidized Lipoprotein(a) in the Vasucular Wall

Aim: A new antibody reacted with an epitope in Lp(a) that has undergone oxidation treatment, but is not present in native Lp(a), was developed. Thus, we determined serum oxidized Lp(a) concentration in healthy volunteers, and coronary artery disease (CAD), diabetes mellitus (DM), and hypertensive patients. Methods: We measured serum levels of oxidized Lp(a), Lp(a), LDL-cholesterol and HDL-cholesterol in 122 consecutive patients who underwent routine coronary angiography and had significant coronary artery stenosis (> 75%), and 164 age-matched healthy volunteers. Moreover, serum native Lp(a), oxidized Lp(a) concentration, and pulse wave velocity (PWV) were determined in 181 hypertensive patients. Results: Oxidized Lp(a) level in CAD patients with DM was significantly higher than in healthy volunteers (p < 0.01). Moreover, serum oxidized Lp(a) concentration showed a significant positive correlation with pulse wave velocity, an index of arteriosclerosis (r = 0.431, p < 0.01). Of importance, the deposition of oxidized Lp(a) was readily detected in calcified areas of coronary arteries in patients with myocardial infarction. Conclusion: The present study demonstrated that oxidized Lp(a) may be a new risk factor for coronary artery disease. As the deposition of oxidized Lp(a) was detected in calcified areas of coronary arteries, oxidized Lp(a) might be implicated in endothelial dysfunction.