Altered serum level of cartilage oligomeric matrix protein and its association with coronary calcification in patients with coronary heart disease

BACKGROUND Cartilage oligomeric matrix protein (COMP) is mainly found in the skeletal system and vascular smooth muscle cells. Recent researches showed that it had a protective function on blood vessels and could also inhibit vascular calcification. We investigated the serum COMPs in coronary heart disease (CHD) patients, and the relationship between serum COMP and the calcification of coronary artery. METHODS A total of 233 consecutive chest pain patients who first underwent coronary angiography followed by multi-slice computed tomography (MSCT) within six months were recruited and divided into two groups according to the coronary angiography luminal diameter narrowing percentages: CHD group (diameter narrowing ≥ 50%, n = 194) and control group (diameter narrowing < 50%, n = 39). The Gensini score, Syntax score and coronary artery calcium score (CACs) were calculated. The serum COMP level was determined using ELISA. RESULTS The levels of COMP were significantly higher in the CHD group than in the control group 155.7 (124.5-194.5) ng/mL vs. 128.4 (113.0-159.9) ng/mL, P = 0.019. There were no correlation between COMP, Gensini score, Syntax score, severity of coronary stenosis and the number of coronary artery with stenosis > 50%. The serum COMP was correlated with age (r = 0.294, P < 0.001), fasting glucose (r = 0.163, P = 0.015), HbA1c (r = 0.194, P = 0.015) and CACs (r = 0.137, P = 0.037). Stepwise linear regression analysis showed that COMP level and age were independent predictors of CACs in the CHD patients (β = 0.402, t = 2.612, P = 0.015; β = 0.472, t = 3.077, P = 0.005). Performance of COMP for predicting CHD was shown as area under curve (AUC): 0.632, 95% CI: 0.549-0.715 and upper tertile CACs was AUC: 0.602, 95% CI: 0.526-0.678 in receiver operating characteristic (ROC) curve analysis. CONCLUSION Calcification of coronary artery was an independent predictor of serum COMPs.