Summary

Matrix Gla protein (MGP) is an extracellular matrix proteinwith wide tissue distribution. It has been demonstrated that theexpression of MGP is detected not only in the normal bloodvessels but also calcified atherosclerotic plaques, and that MGPdeficient mice develop extensive arterial calcification. MGP isthought to be a regulator of vascular calcification. A recentclinical study demonstrates the association between polymorphismsof the MGP gene and increased risk of myocardialinfarction. However, there are no reports of the relationshipbetween serum MGP levels and coronary artery calcification(CAC). We evaluated the severity of CAC using electron-beamcomputed tomography (EBCT), and measured serum MGPlevels by enzyme-linked immunosorbent assay in 115 subjectswith suspected coronary artery disease. CAC scores were cor-Correspondence related with traditional risk factors, such as age, gender, hyper-tension,diabetes, hyperlipidemia and smoking.The serum MGPlevels were lower in patients with CAC than in those withoutCAC (p<0.001). As the severity of CAC increased, there was asignificant decrease in serum MGP levels. Serum MGP levels(U/L) were 116.7 ± 20.3, 104.9 ± 19.2, 95.2 ± 15.2 and 82.2 ±19.7, (medians 115.5, 105.0, 94.8, and 81.9) for the subjects withnormal (CAC score=0), mild (CAC score=1 to 99), moderate(CAC score=100 to 400), and severe (CAC score >400) coronarycalcification, respectively. We found that serum MGPlevels are inversely correlated with the severity of CAC. Thesedata suggest a possible role for MGP in the development ofvascular calcification.