Extracellular matrix disturbances in acute myocardial infarction: relation between disease severity and matrix metalloproteinase-1, and effects of magnesium pretreatment on reperfusion injury.

The purpose of this paper is to clarify the relationship between cytokines, matrix metalloproteinase-1 (MMP-1) and severity of acute myocardial infarction (AMI). Additionally, to investigate whether magnesium (Mg) sulfate pretreatment inhibits myocardial damage in coronary reperfusion therapy for patients with AMI. At first, 34 patients with AMI were enrolled. Then, the patients were classified into 2 groups with or without congestive heart failure (CHF) (C group and NC group, respectively). Interleukin 6 (IL-6), MMP-1 and the hemodynamic parameters were measured. Second, 36 AMI patients treated with coronary reperfusion therapy were enrolled. Patients were divided into 2 groups (18 patients each) as the non-pretreated group (Control group) and the group pretreated with intravenous Mg sulfate (0.27 mmol/kg) (Mg group). IL-6, MMP-1 and the indexes of reperfusion injury were evaluated. There were positive correlations between peak MMP-1 level, and peak creatine kinase value and pulmonary capillary wedge pressure and peak IL-6 level (r = 0.43, r = 0.70, and r = 0.60, respectively) in all patients. There were negative correlations between peak MMP-1 level and left ventricular ejection fraction and cardiac index (r = - 0.52 and r = - 0.55, respectively). The peak blood IL-6 and MMP-1 level increased in AMI, particularly in patients with CHF (C group vs NC group; 130 vs 51 pg/mL and 37 vs 18 ng/mL, both p < 0.01). Additionally, peak IL-6 and peak MMP-1 in the Mg group were lower than those of the control group (39 vs 92 pg/mL and 16 vs 20 ng/mL, p < 0.05 and p = 0.09, respectively). The incidence of reperfusion injury including reperfusion arrhythmia and transient exacerbation of ST elevation in the Mg group was lower than that of control group (17 vs 78% and 2.5 vs 4.7 mm, p < 0.01 and p = 0.08, respectively). These results may suggest that the severity of AMI is reflected by the blood IL-6 and MMP-1 levels and that pretreatment with Mg administration protects the myocardium of patients with AMI from reperfusion injury induced by IL-6 and MMP-1.