Sequential changes in localization of repair-related proteins (heat shock protein 70, ubiquitin and vascular endothelial growth factor) in the different stages of myocardial infarction

Abstract

Aims: The myocardium expresses vascular endothelial growth factor (VEGF), heat shock protein 70 (HSP70), and ubiquitin immediately after the onset of cardiac ischaemia. This study demonstrated the sequential changes in localization of these proteins, in addition to fibronectin and troponin T (TnT), in human hearts with myocardial infarction (MI). Methods and results: Myocardial tissues from 40 autopsied MI cases were immunostained with the five antibodies against VEGF, HSP70, ubiquitin, fibronectin and TnT. Fibronectin was recognized only in the cardiomyocytes with infarction. Although TnT, HSP70, ubiquitin and VEGF were detected in the affected myocardium in the early stages, their expression in cardiomyocytes around infarcted foci were more intense. The cardiomyocytes with coagulative myocytolysis were positive for fibronectin, but negative or weakly positive for TnT, HSP70, ubiquitin and VEGF. In contrast, the cardiomyocytes with colliquative myocytolysis were strongly positive for TnT, HSP70, ubiquitin and VEGF, but negative for fibronectin. Conclusions: Immunostaining using antibodies to fibronectin, TnT, HSP70, ubiquitin and VEGF is useful for the discrimination between infarcted myocytes and ischaemia-damaged myocytes in the human heart with MI at autopsy.