Vimentin is a type III intermediate filament cytoskeletal
protein that is expressed mainly in cells of mesenchymal origin and is involved in a plethora of cellular functions. In this study, myocardial tissues from patients with
ischemic heart disease and a mouse model of acute
myocardial infarction were subjected to immunohistochemistry for
vimentin. We first examined 26 neutral
formalin-fixed,
paraffin-embedded myocardial tissue samples from autopsies of patients that were diagnosed with
ischemic heart disease within 48 h postmortem. Myocardial cells were negative for
vimentin, whereas non-myocardial cells, including vascular endothelium, vascular smooth muscle, fibroblasts, nerve fibers, adipocytes and mesothelial cells, showed positivity. Elevated
vimentin expression was observed around myocardial cells undergoing remodeling, suggesting fibroblastic and endothelial proliferation in these locations. By contrast, myocardial foci that were completely fibrotic did not show upregulated
vimentin expression. Inflammatory foci including macrophages and neutrophils were clearly visualized with
vimentin immunostaining. The same
vimentin expression phenomena as those found in human samples were observed in the mouse model. Our study indicates that immunostaining of
vimentin as a marker for myocardial remodeling and the dynamics of all non-myocardial cell types may be useful for supplementing conventional staining techniques currently used in the diagnosis of
ischemic heart disease.