Figure 1

Histology of the left ventricular myocardium. (a, b) Hematoxylin–Eosin staining of tissue from a representative organ donor displays the histology of a normal myocardium. (c) Picric Sirius red staining shows the network of collagen fibers in red between cardiomyocytes. (d, e) A representative image of tissue from the heart failure group displaying excessive fibroses, hypertrophic cardiomyocytes and irregular nuclei (arrows). (f) Collagen fibers in red between hypertrophic cardiomyocytes.