Increased Autoantibodies Against Oxidized Low-Density Lipoprotein in Coronary Circulation in Patients with Coronary Spastic Angina

Oxidized low-density lipoproteins are important in the progression of atherosclerosis. Autoantibodies against malondialdehyde-modified low-density lipoproteins have been reported to be predictive of the progression of atherosclerosis. This study sought to examine whether plasma levels of autoantibodies against oxidized low-density lipoprotein increase in the coronary circulation in patients with coronary spastic angina. The authors examined plasma antioxidized low-density lipoprotein antibody levels (activity unit values (AcU)/mL) simulta neously in the coronary sinus and the aortic root in 20 patients with coronary spastic angina, 23 patients with stable exertional angina, and 15 control subjects by measuring plasma levels of immunoglobulin G (IgG) autoantibodies against malondialdehyde-modified low-density lipoproteins by enzyme-linked immunosorbent assay. The plasma antioxidized low-density lipoprotein antibody levels (AcU/mL) in the coronary sinus increased in coronary spastic angina (38 ± 16) compared with stable exertional angina (23 ±7) and control subjects (20 ±6) (p≤0.0001). The levels (AcU/mL) in the aortic root also increased in coronary spastic angina (33 ± 12) compared with stable exertional angina (23 ±7) and control subjects (20 ±6) (p<0.005). Furthermore, the coronary sinus-arterial differences of the levels (AcU/mL) were also higher in coronary spastic angina (5 ±9) than in stable exertional angina (0 ±6) and healthy subjects (-1 ±5) (p < 0.05). The generation of malondialdehyde-modified low-density lipoproteins is reported to be associated with atherothrombosis. These findings suggest that elevated levels of autoantibodies against malondialdehyde-modified oxidized low-density lipoproteins in coronary circulation are associated with the development of atherothrombosis from the progression of atherosclerosis rather than with the extent of coronary atheroscle rosis in patients with coronary spastic angina.