The balance of serum matrix metalloproteinase-8 and its tissue inhibitor in acute coronary syndrome and its recurrence

Background: Matrix metalloproteinase-8 (MMP-8) is involved in the breakdown of the extracellular matrix increasing the vulnerability of atherosclerotic lesions. We analysed the diagnostic value of serum MMP-8 and tissue inhibitor of metalloproteinase-1 (TIMP-1) concentrations in acute coronary syndrome (ACS) and their prognostic value in ACS recurrence.

Methods: The population comprised 343 patients with ACS [including 108 unstable angina pectoris and 235 acute myocardial infarctions (AMI)] and 326 healthy controls. Additionally, 157 (45.8%) patients were resampled during the recovery. The ACS patients were followed up for 6 years.

Results: MMP-8, TIMP-1, and their molar ratio distinguished the cases from the controls; C-statistic of the multivariate model (95% CI, p-value) including the MMP-8/TIMP-1 ratio regarding its discriminating ability for AMI was 0.922 (0.893-0.950, p<0.001). After the acute phase of ACS, median MMP-8 and TIMP-1 concentrations decreased (p<0.001) by 34.5 and 28.7%, respectively, but ended up on a different level than those found in the controls. In the follow-up, acute phase and recovery period TIMP-1 concentrations associated with cardiovascular death with hazard ratios 4.31 (2.00-9.26, p<0.001) and 4.69 (1.10-20.01, p=0.037), respectively.

Conclusions: The increase of serum MMP-8 and TIMP-1 concentrations may reflect plaque instability and tissue damage. TIMP-1 concentrations are associated with poor outcome in patients with ACS. The findings may have practical implications in both diagnostics and therapeutics.