Immunohistochemical Study of the Expression of Vascular Endothelial Growth Factor Receptor-2 (KDR/Flk-1) during Myocardial Infarction

Immunohistochemical study showed that vascular endothelial growth factor receptor-2 (KDR/Flk-1) is expressed in the cytoplasm of viable cardiomyocytes, mononuclear cells of the granulation tissue, and smooth muscle cells of intramural arteries at all terms of postinfarction reparative regeneration. Cardiomyocytes were highly heterogeneous by the intensity of staining. This feature was typical of cardiomyocytes in the ischemic area (no staining), as well as within various muscle bundles and one muscle bundle. KDR/Flk-1 expression was revealed in mononuclear cells of the necrotic area (macrophages and fibroblast cells). The distribution of KDR/Flk-1 remained practically unchanged with lengthening of the postinfarction period (more than 7 days). The increase in the heterogeneity of cardiomyocyte staining under these conditions illustrates variations in the intensity of cytoprotective processes during ischemia. KDR/Flk-1 expression in smooth muscle cells of intramural arteries was shown to increase in a later period of observations.