Time-dependent changes in the plasma concentration of matrix metalloproteinase 9 after acute myocardial infarction

Area of Science:

• Cardiology
• Biochemistry
• Molecular Biology

Background:

• Matrix metalloproteinases (MMPs), specifically MMP-2 and MMP-9, are implicated in the pathophysiology of acute myocardial infarction (MI).
• The temporal dynamics of MMP plasma concentrations and their relationship to myocardial damage extent remain incompletely understood.

Purpose of the Study:

• To investigate the time course of plasma concentrations of MMP-2, MMP-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) in patients with acute MI.
• To correlate these concentrations with the size of myocardial infarction.

Main Methods:

• A prospective study involving 20 patients with acute MI who underwent successful reperfusion within 6 hours of symptom onset.
• Patients were stratified into large or moderate MI groups based on left ventriculography.
• Plasma MMP-2, MMP-9, and TIMP-1 levels were measured at multiple time points: admission, 24 hours, 48 hours, 1 week, 4 weeks, 3 months, and 6 months.

Main Results:

• MMP-2 levels showed no significant changes over time in either group.
• Plasma MMP-9 concentrations were significantly higher on admission in patients with large MI compared to moderate MI (195 ± 190 vs. 78 ± 63 ng/ml, p < 0.01).
• MMP-9 levels returned to baseline by 1 week post-MI. TIMP-1 levels increased gradually in the large MI group, returning to baseline at 6 months. The MMP-9/TIMP-1 ratio was elevated on admission in both groups, normalizing by 48 hours.

Conclusions:

• MMP-9 plasma concentrations are elevated early in acute MI, particularly in patients with larger infarcts.
• These findings suggest a potential pathophysiologic role for MMP-9 during the acute phase of myocardial infarction.
• MMP-2 levels do not appear to be significantly altered in the early phase of acute MI in this cohort.