Release characteristics of cardiac proteins after reversible or irreversible myocardial damage

Identification of translational and/or post-translational modifications of cardiac proteins after acute myocardial infarction (AMI) or during the progression to congestive heart failure (CHF) is relevant to gain insight into the pathological mechanisms. Characterization of the release kinetics of these cardiac proteins from the reversibly or irreversibly injured myocardium into the circulation may lead to new diagnostic biomarkers. Although cardiac Troponin I (cTnI) is a well-known biomarker of irreversible myocardial damage in acute myocardial infarction, we demonstrated that the release of cTnI also occurs from viable cardiomyocytes by a stretch-related mechanism, mediated by integrin stimulation. This finding may explain why in several pathological conditions, such as CHF, plasma cTnI levels are elevated in the absence of myocardial necrosis. In addition, we investigated the role of Tenascin-C re-expression during the development of heart failure and the relevance of TNC as a biomarker of ventricular remodeling. In animals with pressure-overload induced ventricle dilatation, TNC gene expression was upregulated, resulting in re-expression of myocardial TNC protein levels and elevated TNC plasma levels, correlating with cardiac function. Plasma TNC levels in patients with CHF declined during cardiac resynchronization therapy. This study indicates that serial plasma TNC levels can be used as a marker of adverse or reverse ventricular remodeling.UBL - phd migration 201