Cytoprotection in the treatment of pediatric cancer: review of current strategies in adults and their application to children

Parenteral glutamine supplementation has no effect on chemotherapy-induced toxicity in children with non-Hodgkin lymphoma

PURPOSE

Protecting patients from the acute and/or chronic toxicity of antineoplastic therapy has become a major concern of oncology centers around the world. Glutamine has been used as a multisystemic protective agent to minimize the side effects arising from the treatment of childhood cancers. In this study, the effect of intravenous glutamine supplementation was investigated in children receiving chemotherapy for non-Hodgkin lymphoma.

METHODS

Twelve children, of 48 to 120 months of age, and who had non-Hodgkin lymphoma were enrolled in the study. Thirty chemotherapy courses were given in combination with glutamine, and 31 chemotherapy courses were given without glutamine. Glutamine was given intravenously for 7 days, at a dose of 0.4 g/kg/d. Patients were evaluated in each course with regard to gastrointestinal, mucosal, and hematological toxicities.

RESULTS

There were no significant differences in the hematological parameters between the 2 groups. The requirements for red blood cells and platelets during the chemotherapy courses were similar in both groups (P=0.64 and 0.40, respectively). Patients supplemented with glutamine developed mucositis in 21 of 30 courses (70%) and patients without glutamine supplements developed mucositis in 23 of 31 courses (74%). The mean duration of mucositis and the mean mucositis score in each course were similar between the 2 groups. In addition, gastrointestinal system and hepatic toxicity did not differ between groups. The mean duration of febrile neutropenia and the length of hospitalization were also similar in both groups (P=0.09 and 0.13, respectively).

CONCLUSIONS

Parenteral glutamine supplementation has no effect on mucositis, fever and febrile neutropenia, length of hospitalization, red blood cell, and platelet requirements, and hematological, gastrointestinal, and hepatic toxicities in children receiving severe chemotherapy.

The protective effect of Canova homeopathic medicine in cyclophosphamide-treated non-human primates

BACKGROUND

Canova activates macrophages and indirectly induces lymphocyte proliferation. Here we evaluated the effects of Canova in cyclophosphamide-treated non-human primates.

METHODS

Twelve Cebus apella were evaluated. Four animals were treated with Canova only. Eight animals were treated with two doses of cyclophosphamide (50 mg/kg) and four of these animals received Canova. Body weight, biochemistry and hematologic analyses were performed for 40 days. Micronucleus and comet assays were performed for the evaluation of DNA damage.

RESULTS

We observed that cyclophosphamide induced abnormal WBC count in all animals. However, the group treated with cyclophosphamide plus Canova presented a higher leukocyte count than that which received only cyclophosphamide. Cyclophosphamide induced micronucleus and DNA damage in all animals. The frequency of these alterations was significantly lower in the Canova group than in the group without this medicine.

CONCLUSIONS

Our results demonstrated that Canova treatment minimizes cyclophosphamide myelotoxicity in C. apella.

Effects of amifostine in combination with cyclophosphamide on female reproductive system

This study investigated the cytoprotective effects of amifostine against the adverse effects of cyclophosphamide relying on ovarian cell death markers and the fertilization rate of the surviving follicles as a late outcome of the study. Combined pretreatment of amifostine with cyclophosphamide enabled partial recovery of antiapoptotic messenger RNA (mRNA) expression levels while a decrease in expression of BAX and Casp3 were identified. The pretreatment of amifostine to cyclophosphamide significantly reduced the proportion of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive primary and preantral follicles (P < .001 and P < .05, respectively). These findings were comparable with the results obtained from protein expression of cleaved caspase 3. The fertilization rate showed a significant capability of amifostine to improve fertilization potency of oocytes exposed to cyclophosphamide (P < .01). In conclusion, administration of amifostine prior to cyclophosphamide might serve as a promising protocol to improve female fertility.

Cytoprotective effects of amifostine in the treatment of childhood malignancies

BACKGROUND

Multi-systemic acute side effects occur, in response to intensive therapies that have been applied in childhood malignancies in recent years. Amifostine has rarely been used in the childhood cancers as a multisystemic protective agent for minimizing these side effects.

PROCEDURE

In this study, the effectiveness of amifostine in combination with chemotherapy for childhood cancer treatment has been researched. Of 11 subjects (2.5 months-17 years) 4 subjects had leukemia, 4 had solid tumor, and 3 had lymphoma. For these 11 subjects, 29 chemotherapy courses were given in combination with amifostine, and 20 without amifostine. Their hematological, gastrointestinal and hepatic toxicity were evaluated according to the WHO toxicity criteria. Amifostine was given intravenously in a dose of 740 mg/m(2), one to three consecutive days depending on the chemotherapy regimen.

RESULTS

The hemoglobin, leukocyte, and platelet levels of the two groups were not statistically different. However, when comparing the courses of the patients receiving the same medications at the same doses, in the group with amifostine, mean erythrocyte transfusion requirement was significantly reduced (P = 0.025). In 31% of the courses with amifostine and 50% of the courses without amifostine, febrile neutropenia developed. Gastrointestinal system and hepatic toxicity was significantly reduced in the courses with amifostine with respect to those without it (P = 0.001). Vomiting, hypotension and nausea were the only side effects related to amifostine.

CONCLUSION

Use of amifostine during the treatment of childhood cancers with intensive chemotherapy and/or radiotherapy significantly reduced the erythrocyte transfusion requirements of the patients as well as gastrointestinal and hepatic toxicity.

Daily subcutaneous amifostine administration during irradiation of pediatric head and neck cancers

Five pediatric patients with head and neck cancers were treated with radiotherapy. Subcutaneous injections of 200 mg flat dose amifostine were given 30 min prior to radiation fractions. A total of 129 amifostine injections were done. Grade 3 nausea occurred three times and emesis only once. Hypotension, hypocalcemia, or allergic reactions following injections were not recorded. No grade 3 or 4 mucosal or skin reactions occurred. After 16 months, all patients were alive and disease-free. There were no grade 3 or 4 side effects of radiotherapy on follow-up. Further studies with more patients are required to determine the role of amifostine in pediatric radiation oncology, but these data should contribute to the clinical spectrum of amifostine use in pediatric oncology.

Diminished molecular response to doxorubicin and loss of cardioprotective effect of dexrazoxane inEgr-1deficient female mice

Doxorubicin (DOX) and VP16 are DNA topoisomerase II inhibitors yet only DOX induces an irreversible cardiotoxicity, likely through DOX-induced oxidative stress. Egr-1 is overexpressed after many stimuli that increase oxidative stress in vitro and after DOX-injection into adult mice in vivo. To investigate Egr-1 function in the heart, we compared the molecular and histological responses of wild type (+/+) and Egr-1 deficient (–/–) female mice to saline, DOX, VP16, the cardioprotectant dexrazoxane (DZR), or DOX+DZR injection. DOX, and to a lesser extent VP16, induced characteristic increases in cardiac muscle and non-muscle genes typical of cardiac damage in +/+ mice, whereas only β-MHC and Sp1 were increased in –/– mice. DZR-alone treated +/+ mice showed increased cardiomyocyte transnuclear width without a change to the heart to body weight (HW/BW) ratio. However, DZR-alone treated –/– mice had an increased HW/BW, increased cardiomyocyte transnuclear width, and gene expression changes similar to DOX-injected +/+ mice. DZR pre-injection alleviated DOX-induced gene changes in +/+ mice; in DZR+DOX injected –/– mice the increases in cardiac and non-muscle gene expression were equal to, or exceeded that, detected after DOX-alone or DZR-alone injections. We conclude that Egr-1 is required for DOX-induced molecular changes and for DZR-mediated cardioprotection.Key words: mice, gene expression, doxorubicin, DNA topoisomerase II inhibitors, cardioprotection.

Oxidative DNA base modifications in peripheral blood mononuclear cells of patients treated with high-dose infusional doxorubicin

In prior studies, it was demonstrated that the redox metabolism of doxorubicin leads to the formation of promutagenic oxidized DNA bases in human chromatin, suggesting a potential mechanism for doxorubicin-related second malignancies. To determine whether a similar type of DNA damage is produced in the clinic, peripheral blood mononuclear cell DNA from 15 women treated with infusional doxorubicin (165 mg/m(2)) as a single agent was examined for 14 modified bases by gas chromatography/mass spectrometry with selected ion monitoring. Prior to the 96-hour doxorubicin infusion, 13 different oxidized bases were present in all DNA samples examined. Chemotherapy, producing a steady-state level of 0.1 microM doxorubicin, increased DNA base oxidation up to 4-fold compared to baseline values for 9 of the 13 bases studied. Maximal base oxidation was observed 72 to 96 hours after doxorubicin treatment was begun; the greatest significant increases were found for Thy Gly (4.2-fold), 5-OH-Hyd (2.5-fold), FapyAde (2.4-fold), and 5-OH-MeUra (2.4-fold). The level of the promutagenic base FapyGua increased 1.6-fold (P < .02), whereas no change in 8-OH-Gua levels was observed in peripheral blood mononuclear cell DNA during the doxorubicin infusion. These results suggest that DNA base damage similar to that produced by ionizing radiation occurs under clinical conditions in hematopoietic cells after doxorubicin exposure. If doxorubicin-induced DNA base oxidation occurs in primitive hematopoietic precursors, these lesions could contribute to the mutagenic or toxic effects of the anthracyclines on the bone marrow.