Background: Osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) are critical regulators of bone remodeling and RANKL/RANK signaling could also play an important role in the remodeling process of several tissues, such as myocardium. Therefore, we investigated whether the serum concentrations of OPG and RANKL correlate with the serum levels of metalloproteinase-1 (MMP-1), MMP-9 and tissue inhibitors of MMP-1 (TIMP-1), which are known regulators of myocardial healing in acute myocardial infarction (AMI) patients.
Methods: We analyzed blood samples from 51 consecutively hospitalized men with AMI, 12 men with established ischemic heart failure (New York Heart Association category II, NYHA-II) and 12 healthy men age-matched to the NYHA-II patients. Serum levels of MMP-1, MMP-9, TIMP-1, OPG and RANKL were quantified using commercially available ELISA kits. AMI patients were sampled 4 days and 6 months after MI.
Results: Our data revealed increased serum levels of OPG, RANKL, MMP-1 and TIMP-1 levels and significant correlations between increased RANKL levels and MMP-1 and TIMP-1 serum levels 6 months after MI. In addition, the ratio OPG/RANKL was very low 6 months after MI, suggesting that the nuclear factor kappa-B signaling is possibly more active 6 months post-MI than it is on day 4 post-MI.
Conclusions: Our data suggest that OPG, RANKL, MMP-1 and TIMP-1 serum levels can be potential mediators of myocardial healing after MI. However, further large studies are needed to confirm the utility of OPG and RANKL as markers of healing after ST elevation in MI.