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(Jltrastucturøl changesz Histopathological studies using several different models
(human, monkeys, dogs, rat, mice and rabbits) showed similarities in cellular changes.
The two most prominent features of ultrastructural damage in adriamycin induced
cardiomyopathic hearts are the loss of fibrils and distension of sarcotubular system. The
distension of sarcotubular system is caused by the adriamycin-induced peroxidative
damage to the membranes. The damage to cellular membranes will cause the increased
permeability of sarcotubular system which will lead to the phenomenon of cytoplasmic
vacuolization. Other structural abnormalities include the development of the
mitochondrial damage with a formation of mitochondrial densities, lipid accumulation
and increased number of lysosomes (Ferrans 1978; Singal et al. 1985). The specificity of
ultrastructural changes in adriamycin induced cardiomyopathy has lead to the
development of the grading system which can be applied to the myocardial biopsy
specimens in order to evaluate and quantify anthracycline-induced myocardial damage
(Bristow et al. 1978; Friedman et al. 1978). However, a correlation between the severity
of ultrastructural changes in biopsy specimens and the overall degree of impairment of
left ventricular function is poor. This can be explained by the fact that despite the severity
of ultrastructural changes, the ventricular function is somehow preserved due to the
action of numerous compensatory mechanisms as well as presence of normal looking
myocytes (Jain 2000).
I.d. The role of oxidative stress in adriamvcin-induced cardiomvopathy and
heart failure
A large number of factors have been implicated in the pathogenesis of adriamycininduced
cardiomyopathy. The list includes; calcium overload (Holmberg and V/illiams
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