Serum α2-macroglobulin levels in ischemic heart disease

[Background]: α2-Macroglobulin is a highly abundant protein in human peripheral circulation and a nonspecific protease inhibitor with potent biological activities. It is implicated in the development of atherosclerosis and cardiac hypertrophy; however, its pathophysiological role in human diseases remains largely unknown. We studied whether or not its serum levels are associated with ischemic coronary artery disease. [Methods]: Using specific and sensitive enzyme-linked immunosorbent assay, we measured serum α2-macroglobulin concentration in 105 patients with diabetes who underwent master double two step test and/or coronary angiography/coronary arterial computed tomography (CT). [Results]: The serum α2-macroglobulin concentration was elevated in patients with diabetes. Patients with positive ischemic changes on master double two-step tests showed significantly higher serum α2-macroglobulin levels than those with negative results (P = 0.0180). Patients with coronary arterial stenosis in the coronary angiography and/or coronary artery CT had distinctly higher α2-macroglobulin values than those without (P = 0.0465). [Conclusions]: Serum α2-macroglobulin concentration was elevated in patients with ischemic heart disease in diabetic population. This highly abundant protein may be involved in the pathophysiology of coronary artery stenosis.