The effect of interferon on mouse myocardial capillaries - An ultrastructural study

BACKGROUND. Cardiotoxicity, including ischemia and myocardial infarction, i s one of the complications observed after treatment with interferon (IFN). Therefore, the question has been raised whether IFN may cause damage to the small myocardial blood vessels. METHODS. In this study, 400 U of IFN-alpha-Zb per g of body weight were inj ected intraperitoneally into 2 groups of C57 Bl mice, 5 days a week for 3 a nd 5 months, respectively. Thin sections of the myocardium were examined wi th a transmission electron microscope and the ultrastructure of the capilla ries was compared with that of control animals. RESULTS. The results showed a statistically significant increase in the thi ckness of the endothelial processes of the myocardial capillary walls in th e mice treated with IFN, with a subsequent decrease in the size of the capi llary lumen. The entire capillary area was not affected. CONCLUSIONS. These findings may serve as an additional explanation for the cardiac complications observed in patients treated with IFN. Cancer 1999;85 : 1375-9. (C) 1999 American Cancer Society.