Monkey myocardial necrosis

Histiopathic examination of the heart is necessarily an integral part of the echocardiographic studies performed to investigate effects on cardiac function in the dog and monkey. Properly formulated patterns of histio-pathologic findings similar to those reports in the safety and toxicology studies, with myocardial necrosis of the papillary muscle, intraventricular septum, and left ventricular wall, are seen. 

In this experiment it was found that the hearts from monkeys fed high fat diets do not develop the myocardial necrosis and fibrosis that were found in male rats. As described in Table XXXIX, two types of lesions were observed. The ( ) or trace lesion was a myocardial lesion consisting of focal interstitial collections of inflammatory cells, occasional focal scars, or groups of swollen interstitial fibroblasts. The authors concluded that these heart lesions were not diet related. The (+) myocardial lesion consisted of multiple small foci of fibroblasts, mononuclear cells, and Antischkow s myocytes. As shown in Table XXXIX this lesion was but rarely observed and then only in male monkeys fed the soybean oil diet. 

It is difficult to assess the relationship of HEAR oils and other oils high in docosenoic acid content to the development of focal myocardial degenerative lesions in the monkey. In a recent study, a series of 312 hearts were selected at random from monkeys used in unrelated toxicological studies (Qureshi, 1979). The monkeys, which included squirrel (Saimiri sciureus) cynomolgus Macaca fascicularis), rhesus Macaca mulatta) and assam (Ma-caca assamensis) monkeys were of both sexes. Chronic interstitial myocarditis was found in 34% of the monkeys, approximately evenly distributed in males and females (Table IX). The lesions varied from slight necrosis to myocarditis with focal accumulation of lymphocytes, mononuclear cells, plasma cells, and some eosinophiles. Inflammation of the myocardium was distributed throughout the heart. These lesions, which occur frequently in primates, apparently are not related to bacterial, viral, or parasitic infections, but may be related to, and precipitated by, stress (Qureshi, 1979 Soto et al., 1964). 

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