Myocyte hypertrophy

This light micrograph shows cardiac myocytes in longitudinal sections. This Movat stain high lights the myocyte sarcoplasm in red and the myocyte nuclei in dark purple. The intercalated discs of the myocytes are highlighted showing the boundaries of he cells. The interstitial capillary endothelial cells are a useful reference for size, as their transverse diameter is usually around 10 µm. Thus showing marked thickening of the myocytes.  Another useful feature that indicates hypertrophy is the presence of enlarged hypercrhomatic myocyte nuclei which can be polyploid and the presence of myocyte binucleation (i.e. two nuclei in a single myocytes). Binucleation is common in hypertrophy, indicating that there has been mitotic division of nuclear material (called karyokinesis) but without cell division (cytokinesis). Moderate to marked pathologic or non-physiologic myocyte hypertrophy is often accompanied by an increase of the extracellular matrix (interstitial fibrosis).