PMC3679521_01
(A). Chimpanzee heart. Note the diffuse cardiomegaly, (B) cut section of the myocardium. Note the thick streaks of pallor within the papillary muscles, (C) interstitial myocardial fibrosis, with pale staining collagen separating myofibers, 40x, H&E, (D) interstitial myocardial fibrosis with adipose tissue infiltrates and mild chronic inflammation, 100x, H&E, (E) interstitial myocardial fibrosis; note the abundant blue staining collagen bands, 40x, trichrome stain, (F) chronic renal infarct with interstitial nephritis and fibrosis, 100x, H&E.
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The heart was diffusely, moderately enlarged (Fig. 1A), with a weight of 497.3 g and displacement of 217 cm3. There were multifocal, firm pale streaks (scarring) predominantly within the left ventricular free wall, interventricular septum, and apex of the heart, with similar though less prominent lesions seen in all chambers (Fig. 1B). Histologic examination of the heart revealed multifocal, moderate to severe, mostly mature fibrosis separating and replacing myofibers in all chambers (Fig. 1C and D). Trichrome staining revealed abundant blue stained collagen separating remaining myofibers (Fig. 1E). Other age-related findings included a focal nodule of renal cortical tubular ectasia and few renal cortical infarcts with fibrosis and chronic inflammation (Fig. 1F).