Increased levels of interleukin-6 and matrix metalloproteinase-9 are of cardiac origin in acute coronary syndrome

Objectives. To investigate the association between inflammatory mediators, matrix degrading enzymes and acute coronary syndrome (ACS) and the impact of early reperfusion therapy on circulating biomarkers. Design. Peripheral serum levels of interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP) and matrix metalloproteinase-9 (MMP-9) were determined in 134 patients with ACS. These biomarkers were serially monitored in ten patients with intravenous thrombolytic therapy (IVT). Results. Serum levels of IL-6, hs-CRP and MMP-9 were higher in unstable angina (UA) and myocardial infarction (MI) groups than in control or SA group (p < 0.05). Peripheral IL-6 level in patients with MI was greater after percutaneous coronary intervention (PCI) (p < 0.01) or IVT (p < 0.05). Serial concentration determination revealed marked elevation of serum IL-6 and MMP-9 levels, both reaching peak values (like creatine kinase-MB). Conclusions. Elevated levels of IL-6, hs-CRP and MMP-9 provide a link between inflammation, matrix degradation and the development and progression of ACS. IL-6 and MMP-9 appear to be released mainly from vulnerable plaque or necrotic myocardium during the acute phase of MI.