Cardiotoxicity of anthracycline antineoplastic drugs--Clinicopathological and experimental studies

Multiple impairments of cutaneous nociceptor function induced by cardiotoxic doses of Adriamycin in the rat

Besides their deleterious action on cardiac muscle, anthracycline-type cytostatic agents exert significant neurotoxic effects on primary sensory neurons. Since cardiac sensory nerves confer protective effects on heart muscle and share common traits with cutaneous chemosensitive nerves, this study examined the effects of cardiotoxic doses of adriamycin on the function and morphology of epidermal nerves. Sensory neurogenic vasodilatation, plasma extravasation, and the neural CGRP release evoked by TRPV1 and TRPA1 agonists in vitro were examined by using laser Doppler flowmetry, the Evans blue technique, and ELISA, respectively. Carrageenan-induced hyperalgesia was assessed with the Hargreaves method. Immunohistochemistry was utilized to study cutaneous innervation. Adriamycin treatment resulted in profound reductions in the cutaneous neurogenic sensory vasodilatation and plasma extravasation evoked by the TRPV1 and TRPA1 agonists capsaicin and mustard oil, respectively. The in vitro capsaicin-, but not high potassium-evoked neural release of the major sensory neuropeptide, CGRP, was markedly attenuated after adriamycin treatment. Carrageenan-induced inflammatory hyperalgesia was largely abolished following the administration of adriamycin. Immunohistochemistry revealed a substantial loss of epidermal TRPV1-expressing nociceptive nerves and a marked thinning of the epidermis. These findings indicate impairments in the functions of TRPV1 and TRPA1 receptors expressed on cutaneous chemosensitive nociceptive nerves and the loss of epidermal axons following the administration of cardiotoxic doses of adriamycin. Monitoring of the cutaneous nociceptor function in the course of adriamycin therapy may well be of predictive value for early detection of the deterioration of cardiac nerves which confer protection against the deleterious effects of the drug.

Adverse Histopathologic Effects of Chemotherapeutic Agents in Childhood Leukemia and Lymphoma

Pathologic material from 84 children with leukemia or lymphoma who died and were autopsied at the University of Wisconsin Hospital between 1967 and 1980 was reviewed to assess the adverse tissue changes due to the chemotherapy administered. In each case the histopathologic findings were correlated with the chemotherapy given. Individual drug dosage is administered (per m2) correlated with the adverse tissue findings at autopsy. Data presented suggest that the drug dose administered should be correlated not only with tumor response but also with tissue effects (some of which produce no noticeable, immediate, clinically apparent changes) to decrease the likelihood of producing irreversible tissue changes.

Pathogenesis of cardiomyopathy caused by anthracycline antibiotics effect of pulmonary stenosis on the development of cardiomyopathy

This study was undertaken to elucidate the effect of pressure load on the development of cardiomyopathy induced by daunorubicin in the right ventricle of rabbits on which pulmonary stenosis had been performed. The right ventricular pressure after occlusion of the pulmonary artery was approximately twice that prior to occlusion. Pulmonary stenosis apparently produced hypertrophy of the right ventricular myocardium within approximately 2 weeks of occlusion. In rabbits with pulmonary stenosis, the characteristic myocardial degenerative changes induced by daunorubicin were found on the right ventricular wall. However, in rabbits without pulmonary stenosis, myocardial lesions were observed only on the left ventricular wall. The pressure load acting as a mechanical stress increases myocardial damage induced by daunorubicin. It is well known that anthracyclines take effect on cells in which nucleic acid synthesis is augmented and the pressure load results in the enhancement of protooncogene expression in myocytes and a subsequent increase in protein synthesis. These results suggest that the pressure load may play a significant role in anthracycline cardiomyopathy by increasing protein synthesis in the myocardium.

Cardiotoxicity of a new anthracycline derivative (SM-5887) following intravenous administration to rabbits: comparative study with doxorubicin

The degree of cardiotoxicity of SM-5887 compared with that of doxorubicin was investigated in rabbits. Two experimental groups were administered high and low doses of SM-5887, respectively. One group was administered doxorubicin and another group was administered the vehicle only were prepared as positive and negative controls, respectively. Drugs were intravenously administered 3 times a week for 8 weeks. At terminus, electrocardiograms were recorded under anesthesia. The blood was collected for haematology and blood biochemistry analyses. Myocardial tissue damage was evaluated using light and electron microscopy. In the electrocardiogram study, prolongation of QTc interval and ST-T change were observed in rabbits administered SM-5887 and doxorubicin. Morphological studies showed that myocardial tissue damage in animals administered SM-5887 was comparable to that in the negative controls, and less than that observed in the positive controls. The general toxicological investigations uniformly indicated lower toxicity in the SM-5887 group than in the doxorubicin group at equivalent dosages. In total, considering the results of antitumor efficacy studies comparing SM-5887 with doxorubicin, these results indicate that the cardiotoxicity of SM-5887 is very slight, and that the general toxicity of SM-5887 is lower than that of doxorubicin.

Ultrastructural alterations of the myocardium induced by doxorubicin. A scanning electron microscopic study

Morphologic changes in Doxorubicin (DXR)-induced cardiomyopathy are characterized by marked dilatation of the sarcoplasmic reticulum (SR). DXR was administered to New Zealand White rabbits for 5 or 8 weeks and the three-dimensional structure of the sarcotubular system in cardiac muscle cells from each rabbit was examined under a field-emission type scanning electron microscope (SEM) after removal of cytoplasmic matrices by the osmium-DMSO-osmium procedure. Five weeks after the initial injection of DXR, partial dilatation of the SR and damaged mitochondria with lysis of cristae were observed three-dimensionally. After 8 weeks, the three-dimensional structure of the SR showed extensive spherical ballooning which could be seen clearly in bold relief. Thus, we could directly visualize structural alterations of the sarcotubular system in DXR-induced cardiomyopathy using the SEM.

Acute effect of calcium channel blockers on adriamycin exposed isolated adult cardiocytes

When tested with isolated, calcium-resistant resting rat cardiocytes in an in vitro assay system, adriamycin exerted a dose-dependent cytotoxic effect which could easily be assessed by the ATP depletion of the heart cells and the loss of vitality as monitored by morphological changes (blebbing, spherical contraction). Apart from extremely high non pharmacological concentrations of verapamil and diltiazem, both calcium antagonists left the cardiocytes intact and without loss of internal ATP when given alone to the medium. Coincubation of adriamycin and verapamil or diltiazem did not increase adriamycin toxicity to the cardiocytes; instead a remarkable ATP preservation by verapamil could be demonstrated when both drugs (adriamycin and verapamil) were incubated simultaneously with the heart cells. This acute protective effect was limited in time and could no longer be detected after 9 hours. Diltiazem in coincubation experiments exerted neither a toxic nor an acute protective effect on adriamycin-exposed heart cells.

Effects of verapamil on doxorubicin-induced mortality and electrolyte changes in the mouse heart

The effects of verapamil on doxorubicin-induced mortality and electrolyte changes were investigated in mice using either 0, 8, 16, or 32 mg/kg verapamil. The verapamil doses were injected by subcutaneous route 24 and 3 hr prior to administration of a single dose of doxorubicin (20 mg/kg, IP), followed by daily treatment with verapamil for 20 subsequent days. Using total deaths or changes in ventricular electrolyte levels as indices of toxicity, there was no evidence that verapamil decreased doxorubicin toxicity. At this dose, doxorubicin increased myocardial calcium and sodium, and decreased magnesium and potassium. Verapamil alone was shown to significantly reduce total ventricular calcium and increase magnesium in a dose-dependent manner. The ventricular sodium and potassium levels were not affected by verapamil treatment. Neither the increase in calcium nor the decrease in heart magnesium content of the ventricles in response to doxorubicin, was lessened by verapamil treatment. Doxorubicin-associated sodium increase in ventricular tissue was greater in groups receiving higher doses of verapamil but decrease of potassium in the ventricles of these animals remained unaffected. We conclude from the findings of the present study that verapamil is inappropriate as an antagonist of the cardiac toxicity resulting from treatment with doxorubicin.