Immunoexpression of MMP-8, MMP-9 and TIMP-2 in dilated cardiomyopathy

Alteration of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) expression has been studied for various cardiac diseases, including dilated cardiomyopathy (DCM), with the significance of surrogate markers of extracellular matrix (ECM) remodeling. In this study, we determined the MMP-8, MMP-9 and TIMP-2 immunoexpression in the heart of patients diagnosed with DCM in relation to a histological composite score (HCS). The study included 40 cases of heart fragments that were processed by the usual paraffin inclusion technique, followed by a semi-quantitative evaluation of histopathological parameters, which summed, allowed the establishment of a HCS. Subsequently, the cases were immunohistochemically processed for MMP-8, MMP-9 and TIMP-2, followed by the semi-quantitative evaluation of their expression intensity. MMP-8 was identified only in myocardiocytes, while MMP-9 and TIMP-2 were present in both myocardiocytes and stroma, but with different intensity. The increasing intensity of MMP-8 and TIMP-2 immunoreactions was significantly associated with low HCS. In case of MMP-9, the immunostaining intensity analysis in relation to the HCS level revealed insignificant differences, but we found an association of increased and moderate intensity with low HCS. The imbalance between TIMPs and MMPs disrupts the ECM architecture and contributes to the remodeling process in DCM, aspect that can be used in the development of new clinical therapies.