Atrial natriuretic peptide and CD34 overexpression in human idiopathic dilated cardiomyopathies

Idiopathic dilated cardiomyopathy (IDCM) is a primary myocardial disease of unknown cause characterized by ventricular chamber enlargement with impaired contractile function. In familial forms of IDCM, mutations of genes coding for cytoskeletal proteins related to force transmission, such as dystrophin, cardiac actin, desmin, and delta-sarcoglycan, have been identified. Here, we report the data of a retrospective investigation carried out to evaluate the expression of atrial natriuretic peptide (ANP), CD34, troponin T and nestin in the myocardium of patients affected with IDCM. Formalin-fixed and paraffin-embedded consecutive tissue sections from the ventricular wall of 10 human normal hearts (NH) following forensic autopsy and 22 IDCM (living explanted hearts) were studied using primary monoclonal antibodies against ANP, CD34, troponin T and nestin by immunohistochemistry. Myocardial fibers were counted independently by three pathologists. Statistics included analysis of variance, log-rank test for Kaplan-Meier analysis, and kappa assessment for intra- and inter-observer variability. ANP and CD34 were significantly overexpressed in IDCM compared to NH (p<0.05). Conversely, troponin T and nestin expression levels did not show significant variation. Inter-observer kappa statistics showed a value of 0.87 and intra-observer kappa statistics a value of 0.98. Evaluation of the marker distribution in the myocardium of patients with IDCM CD34 expression curve was similar to that of troponin T (p