Dystrophin and metalloproteinase 9 in myocardial ischemia: A post-mortem immunohistochemical study.

The presented study evaluated the expression of dystrophin and MMP-9 in cases of sudden cardiac death (SCD) due to coronary atherosclerotic disease (CAD) in order to analyze the characteristics and the chronology of their expression, providing evidence on the possible role in post-mortem diagnosis of myocardial ischemia. The expression of these proteins was also compared to C5b-9 complex and fibronectin expression to evaluate any differences. Two groups of CAD-related SCD, respectively group 1 with gross and/or histological evidence and group 2 with no specific histological signs of myocardial ischemia, were used. A third group formed by cases of acute mechanical asphyxiation was used as a control. The immunohistochemical staining by dystrophin, MMP-9, C5b-9, and fibronectin antibodies was performed. The study revealed that dystrophin and MMP-9 showed different expression in group 1 and group 2 as, respectively, different degree of sarcolemmal staining depletion and increasing of interstitial and granulocytes immunopositivity. Moreover, loss of dystrophin staining and C5b-9 immunopositivity were more significant when compared to MMP-9 increasing. Dystrophin and MMP-9 seemed to be useful immunohistochemical markers for the detection of myocardial ischemic damage. However, the comparison of the four markers suggested that loss of dystrophin could be considered as an earlier marker.