5-methoxytryptophan is a potential marker for post-myocardial infarction heart failure - a preliminary approach to clinical utility

Background: Ventricular remodeling following myocardial infarction (MI) is closely associated with cyclooxygenase-2 (COX-2) expression. 5-methoxytryptophan (5-MTP) was reported to control COX-2 expression. Objectives: To investigeate the association between 5-MTP and post-MI left ventricular remodeling. Methods: This prospective study enrolled 26 non-diabetic patients with first-time ST segment elevation myocardial infarction (STEMI), and 58 controls. Levels of 5-MTP, N-terminal of pro-brain natriuretic peptide (NT-proBNP), aminoterminal propeptide of type III procollagen, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinase-1 were measured at day 1, day 3, 3 months, 6 months, and 1 year post-MI. Echocardiography was performed during the acute stage (within 72 h) and 3 months, 6 months, and 1 year post-MI. Results: The STEMI patients had a significantly lower plasma 5-MTP level at day 1 which reached a nadir at 3 months post-MI. The level of 5-MTP at day 3 post-MI was significantly correlated with the level of NT-proBNP 1 year post-MI, suggesting that the level of plasma 5-MTP in the early phase after MI may predict subsequent cardiac stress and failure. Receiver operating characteristic curve analysis revealed that plasma 5-MTP had the best area under the curve value to predict plasma NT-proBNP 1 year post-MI. Further analysis using net reclassification improvement and integrated discrimination improvement models confirmed that plasma 5-MTP at day 3 post-MI significantly improved the predictive power of each of the parameters. Conclusion: In non-diabetic STEMI patients, plasma 5-MTP levels were associated with biomarkers of post-MI left ventricular remodeling and damage. (C) 2016 Elsevier Ireland Ltd. All rights reserved.