A strong note of caution in using matrix metalloproteinase-1 and its inhibitor, TIMP-1 in serum as biomarkers in systolic heart failure

How could analyzing the activity of two matrix metalloproteinases unveil the cause of sudden cardiac death

Sudden cardiac death is natural, unexpected death, related to cardiovascular disease. Its postmortem elucidation is significant, as the family of the deceased aspires to prevent other sudden deaths. Irrespective of the proper etiological entity, the myocardial collagen matrix remodels, associated with the progression of cardiovascular diseases. It has become evident that many mediators such as humoral factors, transforming growth factor (TGF)-β1 among them, are involved in the remodeling process. Cardiac remodeling is the balance of regenerative and eliminatory processes that include enzymes involved in the degradation of extracellular matrix (ECM) components. Enzymes capable of degrading native fibrillar collagen are interstitial collagenases, specifically matrix metalloproteinases (MMP)-1 and MMP-8. Here, we suggest a technique of visualizing turnover of collagen in cardiac tissue.

Plasma tissue inhibitor of matrix metalloproteinase-1 (TIMP-1): an independent predictor of poor response to cardiac resynchronization therapy

Aims

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a role in left ventricular structural remodelling. The aim of our study was to analyse MMP-2 and TIMP-1 levels as predictors of poor response to cardiac resynchronization therapy (CRT).

Methods and results

A cohort of 42 CRT patients from our centre was prospectively evaluated at baseline and after 12-month follow-up. MMP-2 and TIMP-1 assays were performed prior to CRT implant. Cardiac resynchronization therapy responders were defined as patients who survived, were not transplanted, and increased their basal 6 min walking distance test (6MWDT) by ≥10% or improved their NYHA functional class. Overall, 25 patients (60%) were classed as responders. At 12-month follow-up, six patients (14.2%) had died and one (2.4%) patient had been transplanted. Compared with responders, non-responders had higher levels of TIMP-1 (277 ± 59 vs. 216 ± 46 ng/mL, P = 0.001), MMP-2 (325 ± 115 vs. 258 ± 56 ng/mL, P = 0.02), and creatinine (1.76 ± 0.8 vs. 1.25 ± 0.3 mg/dL, P = 0.01). In a multivariate analysis, TIMP-1 was the only independent predictor of non-response to CRT [OR 0.97, 95% (CI 0.96–0.99) P = 0.005]. TIMP-1≥248 ng/mL predicted non-response with 71% sensitivity and 72% specificity.

Conclusion

TIMP-1 is an independent predictor of non-response in patients treated with CRT.

Matrix metalloproteinase therapy in heart failure

Milestones in the progression to heart failure following myocardial infarction (MI) are changes in left ventricular (LV) geometry and function, termed post-MI remodeling. Critical to this adverse remodeling process are changes in the expression, synthesis, and degradation of myocardial extracellular matrix (ECM) proteins. The myocardial ECM is not a passive entity but a complex and dynamic microenvironment that represents an important structural and signaling system within the myocardium. In particular, basic and clinical studies have provided conclusive evidence that abnormal and persistent activation of the ECM degradation pathway, notably through the matrix metalloproteinases (MMPs), contribute to adverse post-MI remodeling. This review examines recent clinical studies that provide further support to the hypothesis that a specific portfolio of MMPs are diagnostic and likely contributory to LV remodeling and the progression to heart failure after MI. Future translational and clinical research focused on the molecular and cellular mechanisms regulating ECM structure and function likely will contribute to an improved understanding of post-MI LV remodeling and yield novel therapeutic targets.