Increased monomeric CRP levels in acute myocardial infarction: A possible new and specific biomarker for diagnosis and severity assessment of disease

Background: Monomeric CRP (mCRP) plays an important role in the process of atherosclerotic plaque rupture. Recently, it has been reported that mCRP was associated with acute myocardial infarction (AMI). Objectives: The aim of this study was to examine whether mCRP is increased in AMI patients and to investigate the possibility of using circulating mCRP as a biomarker for AMI diagnosis and severity assessment of disease. Methods: A mCRP monoclonal antibody was generated and verified for its specificity. Immunofluorescence was used to assess the localization of mCRP in the infarcted myocardium. Furthermore, 101 AMI, 38 unstable angina pectoris (UAP) and 41 stable angina pectoris (SAP) patients were enrolled, and 43 healthy volunteer were recruited as controls in the study. Venous blood samples were collected to measure the circulating mCRP, cardiac Troponin T and hs-CRP levels. Results: Significantly increased mCRP levels were observed in the infarcted myocardium of model mice. In addition, significantly increased plasma mCRP levels were also detected in AMI patients (20.96 +/- 1.64 ng/ml) compared to those with UAP, SAP or in control patients (all 0 ng/ml, p < 0.001). ROC analysis revealed that circulating mCRP had considerable diagnostic accuracy for AMI with an AUC of 0.928 (95% confidence interval 0.887-0.969). Furthermore, nine patients (9/101, 8.91%) in AMI group died before the 30-day follow-up, and their plasma mCRP concentration was significantly higher than those in surviving patients (36.70 +/- 10.26 vs. 19.41 +/- 1.43 ng/ml, P = 0.002). Conclusions: These results indicate that mCRP is increased in AMI and that circulating mCRP might be a potential biomarker for diagnosis and severity assessment of disease in AMI. (C) 2015 Elsevier Ireland Ltd. All rights reserved.