Peripheral levels of matrix metalloproteinase-9, interleukin-6, and C-reactive protein are elevated in patients with acute coronary syndromes: correlations with serum troponin I

BACKGROUND: Acute coronary syndromes (ACS) are characterized by activation of systemic and local inflammatory mediators. The interrelation between these soluble inflammatory markers and their association with markers of myocardial necrosis have not been extensively studied. HYPOTHESIS: The study was undertaken to evaluate the association of the systemic levels of matrix metalloproteinase-9 (MMP-9) and the tissue inhibitor of metalloproteinase-1 (TIMP-1), with C-reactive protein (CRP), interleukin-6 (IL-6), and serum troponin-I in patients admitted with ACS. METHODS: Analysis of serum concentrations of the above inflammatory markers was performed in 53 patients with unstable angina (UA) and in 15 with non-ST-segment elevation myocardial infarction (NSTEMI) within 48 h of admission, and 34 patients with stable coronary artery disease. RESULTS: Compared with patients with stable angina, those with ACS had elevated admission levels of MMP-9 (p = 0.04), CRP (p < 0.001), and IL-6 (p = 0.001), but not TIMP-1 (p = 0.55). Compared with patients with UA, those with NSTEMI also had higher levels of IL-6 (p < 0.001), CRP (p = 0.002), and MMP-9 (p = 0.05). CONCLUSIONS: In patients with ACS, the admission levels of inflammatory mediators, including MMP-9, CRP, and IL-6 are significantly elevated, specifically in association with serum troponin I. Systemic and local markers of inflammatory activity may be directly associated with myocardial injury.