Oxidant/antioxidant parameters and their relationship with chemotherapy in Hodgkin's lymphoma

Serum total oxidant and anti-oxidant status in children with cancer

BACKGROUND

Oxidative stress has a potential role in carcinogenesis. Anti-oxidant enzymes have a neutralizing effect on both cancer initiation and progression. We aimed to assess the oxidant and anti-oxidant levels of pediatric cancer patients and to compare the levels in healthy controls.

MATERIALS AND METHODS

The study involved 105 pediatric cancer patients (40 undergoing chemotherapy, 65 survivors) and 40 healthy children. The serum total oxidant status (TOS) and total anti-oxidant status (TAS) were measured.

RESULTS

The oxidative stress index was significantly lower in pediatric cancer patients compared to the levels in the controls (0.20 ± 0.07 vs. 0.26 ± 0.10; P = 0.001). The mean serum TAS level was significantly higher in patient groups compared to the level in the control (1.87 ± 0.48 vs. 1.63 ± 0.32 mmol/L, P = 0.001). The TAS level of children with cancer in survivors was also found to be significantly higher compared to the levels in the control group (1.85 ± 0.45 vs. 1.63 ± 0.32 mmol/L, P = 0.005). Radiotherapy, surgery, relapsed disease, presence of metastases, and receiving enteral nutritional support caused no change in the TAS/TOS level.

CONCLUSION

It has been revealed for the first time that the serum total anti-oxidant level was high in children undergoing chemotherapy and the survivor group as well. Moreover, the oxidative stress index was low in children with cancer. Longitudinal prospective studies are needed to reveal the alterations in oxidant status among children with cancer.

Analysis of redox status and HDL subclasses in patients with lymphoma and the associations with FDG-PET/CT findings

Newer research points to alterations in the plasma redox status and the HDL subclass distributions in cancer. We aimed to assess the redox status and the HDL subclass distributions, lipids, and inflammatory markers in lymphoma patients in order to determine whether they were correlated with changes in FDG-PET/CT scans. At the beginning of this study, redox status, HDL subclasses, lipids, and inflammation biomarkers were determined in 58 patients with lymphoma (Hodgkin lymphoma, n=11 and non-Hodgkin lymphoma, n=47), and these same measurements were reassessed during their ensuing treatment (in 25 patients). Initially, the total oxidation status (TOS), the prooxidant-antioxidant balance (PAB), the OS index (OSI), the total protein sulfhydryl groups (SH-groups), and the advanced oxidation protein products (AOPP) were significantly higher in lymphoma patients as compared to healthy subjects, but the total antioxidant status (TAS) was significantly reduced. The PAB had a strong correlation with the CRP and interleukin-6 (rho=0.726, p<0.001; rho=0.386, p=0.003). The correlations between these parameters and the maximum standardized uptake values (SUVmax) were: PAB, rho=0.335 and p=0.010; SH-groups, rho=0.265 and p=0.044; CRP, rho=0.391 and p=0.002; HDL3b, rho=0.283 and p=0.031; HDL2b, rho= -0.294 and p=0.025; and HDL size, rho= -0.295 and p=0.024. The reductions in SUVmax between two follow-up points were associated with increases in the OSI, TOS, and SH-groups, as well as a reduction in the PAB and TAS. In conclusion, the redox parameters in patients with lymphoma were consistent with FDG-PET/CT findings. Targeting the redox status parameters and the HDL subclasses could be potential strategies in the molecular fight against lymphoma.

Targeting ryanodine receptor type 2 to mitigate chemotherapy-induced neurocognitive impairments in mice

Chemotherapy-induced cognitive dysfunction (chemobrain) is an important adverse sequela of chemotherapy. Chemobrain has been identified by the National Cancer Institute as a poorly understood problem for which current management or treatment strategies are limited or ineffective. Here, we show that chemotherapy treatment with doxorubicin (DOX) in a breast cancer mouse model induced protein kinase A (PKA) phosphorylation of the neuronal ryanodine receptor/calcium (Ca2+) channel type 2 (RyR2), RyR2 oxidation, RyR2 nitrosylation, RyR2 calstabin2 depletion, and subsequent RyR2 Ca2+ leakiness. Chemotherapy was furthermore associated with abnormalities in brain glucose metabolism and neurocognitive dysfunction in breast cancer mice. RyR2 leakiness and cognitive dysfunction could be ameliorated by treatment with a small molecule Rycal drug (S107). Chemobrain was also found in noncancer mice treated with DOX or methotrexate and 5-fluorouracil and could be prevented by treatment with S107. Genetic ablation of the RyR2 PKA phosphorylation site (RyR2-S2808A) also prevented the development of chemobrain. Chemotherapy increased brain concentrations of the tumor necrosis factor-α and transforming growth factor-β signaling, suggesting that increased inflammatory signaling might contribute to oxidation-driven biochemical remodeling of RyR2. Proteomics and Gene Ontology analysis indicated that the signaling downstream of chemotherapy-induced leaky RyR2 was linked to the dysregulation of synaptic structure-associated proteins that are involved in neurotransmission. Together, our study points to neuronal Ca2+ dyshomeostasis via leaky RyR2 channels as a potential mechanism contributing to chemobrain, warranting further translational studies.

Epirubicin toxicity in rat's ovary and uterus: A protective role of 3-Indolepropionic acid supplementation

The "anthracycline, Epirubicin (EPI)," in managing breast cancer, is highly cytotoxic. Tryptophan-derived 3-indolepropionic acid (3-IPA) decreases oxidative damage, and its prospect of alleviating EPI-induced cytotoxicity was examined in rats' hypothalamus-ovary-uterus axis. Female rats: Control, EPI (2.5 mg/kg), 3-IPA alone (40 mg/kg), EPI+3-IPA (2.5 mg/kg + 20 mg/kg), EPI + 3-IPA2 (2.5 mg/kg + 40 mg/kg) were treated for 28 days. Subsequently, reproductive hormones, oxidative and inflammatory stress biomarkers, and tissue histology were examined. 3-IPA prevented EPI-induced decreases in the follicle-stimulating hormone, estradiol, progesterone and prolactin levels. EPI-mediated reduction in antioxidant enzymes, reduced glutathione and total sulfhydryl groups were partially counteracted by 3-IPA co-treatment. Increased oxidative and inflammatory stress biomarkers caused by treatment with EPI alone were lessened by 3-IPA co-treatment. Also, 3-IPA reduced histological damage in the examined tissues. Conclusively, 3-IPA ameliorated biochemical markers and tissue injury caused by EPI treatment alone via an antioxidative and anti-inflammatory mechanism while stabilising serum hormone dynamics.

Potential Molecular Biomarkers of Central Nervous System Damage in Breast Cancer Survivors

Damage of the central nervous system (CNS), manifested by cognitive impairment, occurs in 80% of women with breast cancer (BC) as a complication of surgical treatment and radiochemotherapy. In this study, the levels of ICAM-1, PECAM-1, NSE, and anti-NR-2 antibodies which are associated with the damage of the CNS and the endothelium were measured in the blood by ELISA as potential biomarkers that might reflect pathogenetic mechanisms in these patients. A total of 102 patients enrolled in this single-center trial were divided into four groups: (1) 26 patients after breast cancer treatment, (2) 21 patients with chronic brain ischemia (CBI) and asymptomatic carotid stenosis (ICA stenosis) (CBI + ICA stenosis), (3) 35 patients with CBI but without asymptomatic carotid stenosis, and (4) 20 healthy female volunteers (control group). Intergroup analysis demonstrated that in the group of patients following BC treatment there was a significant increase of ICAM-1 (mean difference: −368.56, 95% CI −450.30 to −286.69, p < 0.001) and PECAM-1 (mean difference: −47.75, 95% CI −68.73 to −26.77, p < 0.001) molecules, as compared to the group of healthy volunteers. Additionally, a decrease of anti-NR-2 antibodies (mean difference: 0.89, 95% CI 0.41 to 1.48, p < 0.001) was detected. The intergroup comparison revealed comparable levels of ICAM-1 (mean difference: −33.58, 95% CI −58.10 to 125.26, p = 0.76), PECAM-1 (mean difference: −5.03, 95% CI −29.93 to 19.87, p = 0.95), as well as anti-NR-2 antibodies (mean difference: −0.05, 95% CI −0.26 to 0.16, p = 0.93) in patients after BC treatment and in patients with CBI + ICA stenosis. The NSE level in the group CBI + ICA stenosis was significantly higher than in women following BC treatment (mean difference: −43.64, 95% CI 3.31 to −83.99, p = 0.03). Comparable levels of ICAM-1 were also detected in patients after BC treatment and in the group of CBI (mean difference: −21.28, 95% CI −111.03 to 68.48, p = 0.92). The level of PECAM-1 molecules in patients after BC treatment was also comparable to group of CBI (mean difference: −13.68, 95% CI −35.51 to 8.15, p = 0.35). In conclusion, among other mechanisms, endothelial dysfunction might play a role in the damage of the CNS in breast cancer survivors.

Mitochondria and Their Relationship with Common Genetic Abnormalities in Hematologic Malignancies

Hematologic malignancies are known to be associated with numerous cytogenetic and molecular genetic changes. In addition to morphology, immunophenotype, cytochemistry and clinical characteristics, these genetic alterations are typically required to diagnose myeloid, lymphoid, and plasma cell neoplasms. According to the current World Health Organization (WHO) Classification of Tumors of Hematopoietic and Lymphoid Tissues, numerous genetic changes are highlighted, often defining a distinct subtype of a disease, or providing prognostic information. This review highlights how these molecular changes can alter mitochondrial bioenergetics, cell death pathways, mitochondrial dynamics and potentially be related to mitochondrial genetic changes. A better understanding of these processes emphasizes potential novel therapies.

Redox imbalance induced by docetaxel in the neuroblastoma SH-SY5Y cells: a study of docetaxel-induced neuronal damage

Objectives

In cancer survivors, chemotherapy-associated adverse neurological effects are described as side effects in non-targeted tissue. We investigated the role of redox-imbalance in neuronal damage by a relative low dose of Docetaxel (DTX).

Methods

The neuroblastoma cells (SH-SY5Y cells) were exposed to DTX at a dose of 1.25 nM for 6 h. Antioxidant defenses (i.e. ascorbic acid, glutathione, and catalase) and lipid oxidation products (i.e. F₂-isoprostanes) were evaluated. To investigate cell ultrastructure and tubulin localisation, transmission electron microscopy (TEM) and immunofluorescence techniques were applied.

Results

In the SH-SY5Y cells, DTX induced a significant reduction of total glutathione (P < 0.001) and ascorbic acid (P < 0.05), and an increase in both total F₂-Isoprostanes (P < 0.05) and catalase activity (P < 0.05), as compared to untreated cells. Additionally, TEM showed a significant increase in cells with apoptotic characteristics. Immunolocalisation of tubulin showed a compromised cytoskeletal organisation.

Discussion

The investigated sublethal dose of DTX, to which non-targeted cells may be exposed throughout the duration of chemotherapy treatment, induces a redox imbalance resulting in a specific modulation of the antioxidant response. This study provides new insights into DTX-induced cellular mechanisms useful for evaluating whether the concomitant use of antioxidants associated with chemotherapy mitigates chemotherapy side effects in cancer survivors.

Protein Carbonylation and Lipid Peroxidation in Hematological Malignancies

Among the different mechanisms involved in oxidative stress, protein carbonylation and lipid peroxidation are both important modifications associated with the pathogenesis of several diseases, including cancer. Hematopoietic cells are particularly vulnerable to oxidative damage, as the excessive production of reactive oxygen species and associated lipid peroxidation suppress self-renewal and induce DNA damage and genomic instability, which can trigger malignancy. A richer understanding of the clinical effects of oxidative stress might improve the prognosis of these diseases and inform therapeutic strategies. The most common protein carbonylation and lipid peroxidation compounds, including hydroxynonenal, malondialdehyde, and advanced oxidation protein products, have been investigated for their potential effect on hematopoietic cells in several studies. In this review, we focus on the most important protein carbonylation and lipid peroxidation biomarkers in hematological malignancies, their role in disease development, and potential treatment implications.

Assessment of oxidative/anti-oxidative markers and DNA damage profile induced by chemotherapy in algerian children with lymphoma

The aim of this study was to assess the oxidative stress and the genotoxicity induced by chemotherapy by the determination of plasma malondialdehyde (MDA) level, protein carbonyl (PC) content, superoxide dismutase (SOD) activity and lymphocyte DNA damage in Algerian children with lymphoma. The study population included thirty patients with lymphoma and fifty healthy controls. Patients were treated with 2 courses of OEPA (oncovin 1,5 mg/m², etoposide 125 mg/m², prednisone 60 mg/m² and doxorubicin 40 mg/m²) followed by 2 to 4 courses of COPDAC (cyclophosphamide 500 mg/m², oncovin 1,5 mg/m², dacarbazine 250 mg/m² and prednisone 40 mg/m²). Plasma levels of MDA, PC and SOD were spectrophotometrically measured. DNA damage was assessed by alkaline comet assay in peripheral blood leukocytes. Plasma MDA, PC levels and lymphocyte DNA damage, were found to be significantly higher in lymphoma patients than in controls (p < 0.001). Whereas, SOD activity in lymphoma patients was significantly lower than in healthy controls (p < 0.001). There were significant positive correlations between DNA damage, MDA and PC in patients (r = 0.96, p < 0.001, r = 0.97, p < 0.001, respectively), and negative correlation with SOD (r = -0.87, p < 0.01). Our results indicated that, leukocytes DNA damage and oxidative stress were significantly higher in lymphoma patients, suggesting that the direct effect of chemotherapy and the alteration of the redox balance may influence oxidative/antioxidative status.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Correlation Between Superoxide Dismutase Serum Level Alteration with Neck Metastatic Tumor Post Cisplatin-Paclitaxel Chemotherapy Response in Nasopharyngeal Carcinoma Patients

Nasopharyngeal carcinoma (NPC) is a malignant tumor in the nasopharynx. The patients treated with neoadjuvan combination chemotherapy cisplatin-paclitaxel while waiting a radiotherapy. This combination can produce a very high reactive oxygen species (ROS) level. Our body has a protective mechanism against oxidant through superoxide dismutase (SOD) that can inhibit DNA chain damage from ROS induction produced by chemotherapy in NPC patients. This study aimed to analyze the correlation between SOD level alteration with neck metastatic tumor response after cisplatin-paclitaxel chemotherapy. This was a cohort study. Thirty samples examined for neck metastasis tumor volume (VTM) and serum SOD were examined with ELISA pre- and postchemotherapy. Statistical significance was defined as p < 0.05. Mean SOD serum level pre-chemotherapy and post-chemotherapy were was 179.5 and 209.1, respectively. Mean tumor metastaic volume pre and post chemotherapy were 127.3 and 62.7, respectively. The correlation test with the result (r) 0.180 and p = 0.340. There was no correlation between SOD serum level alteration with VTM volume post cisplatin-paclitaxel chemotherapy in NPC patients.

Brain cortical structural differences between non-central nervous system cancer patients treated with and without chemotherapy compared to non-cancer controls: a cross-sectional pilot MRI study using clinically-indicated scans

Background

Cognitive deficit associated with cancer and its treatment is called cancer-related cognitive impairment (CRCI). Increases in cancer survival have made understanding the basis of CRCI more important. CRCI neuroimaging studies have traditionally used dedicated research brain MRIs in breast cancer survivors after chemotherapy with small sample sizes; little is known about other non-central nervous system (CNS) cancers after chemotherapy as well as those not exposed to chemotherapy. However, there may be a wealth of unused data from clinically-indicated MRIs that could be used to study CRCI.

Objective

Evaluate brain cortical structural differences in those with various non-CNS cancers using clinically-indicated MRIs.

Design

Cross-sectional.

Patients

Adult non-CNS cancer and non-cancer control (C) patients who underwent clinically-indicated MRIs.

Methods

Brain cortical surface area and thickness were measured using 3D T1-weighted images. An age-adjusted linear regression model was used and the Benjamini and Hochberg false discovery rate (FDR) corrected for multiple comparisons. Group comparisons were: cancer cases with chemotherapy (Ch+), cancer cases without chemotherapy (Ch-) and subgroup of lung cancer cases with and without chemotherapy vs C.

Results

Sixty-four subjects were analyzed: 22 Ch+, 23 Ch- and 19 C patients. Subgroup analysis of 16 lung cancer (LCa) patients was also performed. Statistically significant decreases in either cortical surface area or thickness were found in multiple regions of interest (ROIs) primarily within the frontal and temporal lobes for all comparisons. Effect sizes were variable with the greatest seen in the left middle temporal surface area ROI (Cohen's d -0.690) in the Ch- vs C group comparison.

Limitations

Several limitations were apparent including a small sample size that precluded adjustment for other covariates.

Conclusions

Our preliminary results suggest that, in addition to breast cancer, other types of non-CNS cancers treated with chemotherapy may result in brain structural abnormalities. Similar findings also appear to occur in those not exposed to chemotherapy. These results also suggest that there is potentially a wealth of untapped clinical MRIs that could be used for future CRCI studies.

Diminished stress resistance and defective adaptive homeostasis in age-related diseases

Adaptive homeostasis is defined as the transient expansion or contraction of the homeostatic range following exposure to subtoxic, non-damaging, signaling molecules or events, or the removal or cessation of such molecules or events (Mol. Aspects Med. (2016) 49, 1-7). Adaptive homeostasis allows us to transiently adapt (and then de-adapt) to fluctuating levels of internal and external stressors. The ability to cope with transient changes in internal and external environmental stress, however, diminishes with age. Declining adaptive homeostasis may make older people more susceptible to many diseases. Chronic oxidative stress and defective protein homeostasis (proteostasis) are two major factors associated with the etiology of age-related disorders. In the present paper, we review the contribution of impaired responses to oxidative stress and defective adaptive homeostasis in the development of age-associated diseases.

Impact of chemotherapy on symptom profile, oxidant-antioxidant balance and nutritional status in non-small cell Lung Cancer

BACKGROUND

Lung cancer is associated with an oxidant-antioxidant imbalance that is implicated in tumor progression. However, the association of this imbalance on disease burden and treatment response is unclear. The effect of chemotherapy on oxidative stress, antioxidant status, and nutritional profile in patients with advanced nonsmall cell lung cancer (NSCLC) was prospectively evaluated.

SUBJECTS AND METHODS

Patients with confirmed cytological/histological diagnosis of NSCLC were recruited. Performance status was determined using the Eastern Cooperative Oncology Group grading and the Karnofsky Performance Scale. Skin fold anthropometry was done for nutritional assessment. All patients received chemotherapy with intravenous carboplatin and paclitaxel at three-weekly intervals. Response was assessed after four cycles by repeat imaging. Plasma levels of total antioxidant status (TAS), malondialdehyde (MDA), and glutathione peroxidase (GPx) levels were estimated using commercially available kits, and the change was correlated with clinical outcome, response to chemotherapy, performance status, and nutritional profile.

RESULTS

Thirty-five cases were studied (92% males), with a mean (SD) age of 56.2 (9.3) years. Following treatment, majority of patients demonstrated stable disease (n = 15 [42%]), followed by partial response (29%), progressive disease (22%), and complete remission (6%). Significant improvement occurred in respiratory symptoms. Body fat declined while subscapular skinfold thickness and 6-min walk distance increased. Spirometric values and performance status remained unchanged. GPx levels declined significantly while no notable change was observed in MDA and TAS levels.

CONCLUSIONS

Chemotherapy for NSCLC improves symptoms, nutritional status, and exercise capacity but worsens the antioxidant status.

Chemotherapy, cognitive impairment and hippocampal toxicity

Cancer therapies can be associated with significant central nervous system (CNS) toxicity. While radiation-induced brain damage has been long recognized both in pediatric and adult cancer patients, CNS toxicity from chemotherapy has only recently been acknowledged. Clinical studies suggest that the most frequent neurotoxic adverse effects associated with chemotherapy include memory and learning deficits, alterations of attention, concentration, processing speed and executive function. Preclinical studies have started to shed light on how chemotherapy targets the CNS both on cellular and molecular levels to disrupt neural function and brain plasticity. Potential mechanisms include direct cellular toxicity, alterations in cellular metabolism, oxidative stress, and induction of pro-inflammatory processes with subsequent disruption of normal cellular and neurological function. Damage to neural progenitor cell populations within germinal zones of the adult CNS has been identified as one of the key mechanisms by which chemotherapy might exert long-lasting and progressive neurotoxic effects. Based on the important role of the hippocampus for maintenance of brain plasticity throughout life, several experimental studies have focused on the study of chemotherapy effects on hippocampal neurogenesis and associated learning and memory. An increasing body of literature from both animal studies and neuroimaging studies in cancer patients suggests a possible relationship between chemotherapy induced hippocampal damage and the spectrum of neurocognitive deficits and mood alterations observed in cancer patients. This review aims to briefly summarize current preclinical and neuroimaging studies that are providing a potential link between the neurotoxic effects of chemotherapy and hippocampal dysfunction, highlighting challenges and future directions in this field of investigation.

Clinical characteristics, pathophysiology, and management of noncentral nervous system cancer-related cognitive impairment in adults

Answer questions and earn CME/CNE Over the past few decades, a body of research has emerged confirming what many adult patients with noncentral nervous system cancer have long reported-that cancer and its treatment are frequently associated with cancer-related cognitive impairment (CRCI). The severity of CRCI varies, and symptoms can emerge early or late in the disease course. Nonetheless, CRCI is typically mild to moderate in nature and primarily involves the domains of memory, attention, executive functioning, and processing speed. Animal models and novel neuroimaging techniques have begun to unravel the pathophysiologic mechanisms underlying CRCI, including the role of inflammatory cascades, direct neurotoxic effects, damage to progenitor cells, white matter abnormalities, and reduced functional connectivity, among others. Given the paucity of research on CRCI with other cancer populations, this review synthesizes the current literature with a deliberate focus on CRCI within the context of breast cancer. A hypothetical case-study approach is used to illustrate how CRCI often presents clinically and how current science can inform practice. While the literature regarding intervention for CRCI is nascent, behavioral and pharmacologic approaches are discussed.

Chemotherapy-related cognitive dysfunction: current animal studies and future directions

Cognitive impairment is a potential long-term side effect of adjuvant chemotherapy that can have a major impact on the quality of life of cancer survivors. There is a growing number of preclinical studies addressing this issue, thereby extending our knowledge of the mechanisms underlying chemotherapy-induced neurotoxicity. In this review, we will summarize the recent advances and important findings presented in these studies. Emerging challenges, such as the development of neuroprotective strategies, and the role of the blood-brain barrier on cognitive impairment will be described and future directions in this field of investigation will be outlined.

Investigation of the antioxidant status in multiple myeloma patients: effects of therapy

BACKGROUND

Multiple myeloma is a malignant silent incurable plasma cell disorder. The present study aimed to assessed the activation of the oxidative stress pathway in affected patients.

MATERIALS AND METHODS

Advanced oxidation protein products (AOPPs), malondialdehyde (MDA), adenosine deaminase (ADA), total antioxidant capacity (TAC) levels, glutathione, ascorbic acid (vitamin C), α-tocopherol (vitamin E) in addition to related enzymes glutathione peroxidase (GSH-Px), glutathione reductase (GSH-R) and superoxide dismutase (SOD) were analyzed in sixty patients with multiple myeloma before and after one month treatment with induction therapy.

RESULTS

The results of the study showed a significant elevation in AOPPs, MDA, ADA levels in patients with multiple myeloma before and after treatment in comparison to healthy control samples In contrast TAC glutathione, vitamin C and E, and the antioxidant enzymes levels were decreased significantly. On comparing samples of MM patients after treatment, there was significant increase of TAC glutathione, vitamin C and E, and the antioxidant enzymes in parallel with decreasing AOPPs, MDA and ADA levels in comparison with samples of patients before treatment.

CONCLUSIONS

The results indicate oxidative stress and DNA damage activity increase in MM and are alleviated in response to therapy.

Neurocognitive effects of chemotherapy and endocrine therapies in the treatment of breast cancer: recent perspectives

With an estimated 207,090 patients diagnosed with breast cancer in 2010, the role of chemotherapy-induced cognitive impairment is of growing importance. Studies to determine the impact of chemotherapy-induced cognitive impairment have been hindered by difficulties in study-design, in particular, study methodology. Here, we present a review of existing studies and discuss several mechanisms for chemotherapy-induced neurocognitive impairment in breast cancer patients, such as direct neurotoxic injury, telomere shortening, oxidative stress, cytokine dysregulation, estrogen-mediated effects, and the role of certain genetic polymorphisms. Decreased estrogen levels may serve as a link between multiple mechanisms potentiating the effects of the chemotherapy-induced cognitive impairment.

Ischemia-modified albumin as a biochemical marker in children with neuroblastoma and soft tissue sarcomas

In this study, the levels of ischemia-modified albumin (IMA) in pediatric oncology patients with soft tissue sarcomas (STSs) and neuroblastoma (NB) were analyzed. To date, there have been no studies concerning IMA in these groups of patients. Ninety-nine children with STSs and NB were analyzed from 2006 to 2009, and 30 healthy children were also enrolled in the study. IMA levels were measured throughout treatment in all patients. The levels of IMA in all cancer patients (mean 116.8±39.3 U/ml), in patients with STSs (mean 119.8±27.5 U/ml), and in patients with NB (mean 114.6±36.6 U/ml) were significantly higher than in the control patients (mean 87.3±38.3 U/ml; P=0.0013, 0.0066, and 0.0164, respectively). IMA levels increased before and during the treatment compared with levels in the controls. The determination of IMA levels in pediatric oncology patients with poor prognoses from STSs and NB may play an important role in predicting response to therapy and overall outcome.

The antioxidant status and response to therapy in children with soft tissue sarcomas and neuroblastoma

BACKGROUND

Antioxidant systems in cells maintain the proper homeostasis of reactive oxygen species, which at high concentrations can induce carcinogenesis. The aim of this study was to evaluate the serum levels of ischemia-modified albumin (IMA), erythrocyte superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) as markers for prognosis in children with neuroblastoma (NB) and soft tissue sarcomas (STS), two cancer types for which reliable prognostic factors are needed.

PROCEDURE

SOD, GSH-Px, and IMA were measured before and during responses to therapy assessment in 99 children with NB and STS and in 30 healthy controls.

RESULTS

There were no statistically significant differences in the erythrocyte SOD and GSH-Px activities between the patients with cancer and healthy controls. The levels of IMA in patients with STS and NB were found to be significantly higher than in the controls (P = 0.0013; P = 0.0066, and 0.0164, respectively). Decreased activities of SOD and GSH-Px were found in all patients with poor-responding (PRS) cancers and decreased SOD activity was found in patients with PRS NB. An increase in GSH-Px was observed in patients with good-responding (GR) NB. All patients with GR cancers demonstrated higher SOD and GSH-Px activities than patients with PRS cancers.

CONCLUSIONS

While determining the levels of specific antioxidants as antioxidant-barrier parameters in children with cancer may be valuable in predicting therapeutic responses as well as outcomes, additional studies are required.

Oxidative stress markers may not be early markers of doxorubicin-induced cardiotoxicity in rabbits

This study was performed to determine whether oxidative stress markers may be early markers of doxorubicin-induced cardiotoxicity. Forty-four male rabbits were randomly divided into four doxorubicin groups and one control group (8 rabbits). The control group received saline, and rabbits in the doxorubicin groups received 2 mg/kg doxorubicin weekly for 1 (group 1, 8 rabbits), 2 (group 2, 8 rabbits), 4 (group 3, 9 rabbits) or 8 (group 4, 11 rabbits) weeks. Echocardiography was performed to measure left ventricular ejection fraction, fractional shortening and the E/A ratio. Cardiotoxicity scores were determined by light microscopy using Billingham's method and by electron microscopy. Serum glutathione peroxidase (GPx) and superoxide dismutase (SOD) concentrations were quantified by a rabbit-specific enzyme-linked immunosorbent assay (ELISA). The Billingham cardiomyopathy scores for the rabbits in groups 3 or 4 were significantly higher (p<0.05) compared to the scores for the control group or groups 1 and 2. Myocardial injury was demonstrable by electron microscopy in groups 2, 3 and 4 (p<0.05). Serum GPx concentrations decreased only in group 4 compared to the control group (p<0.05). No changes were measured in serum SOD concentration. The results indicate that oxidative stress markers may not be early markers of doxorubicin-induced cardiotoxicity.

Chemotherapy associated central nervous system damage

Chemotherapy is commonly associated with harmful effects to multiple organ systems, including the central nervous system (CNS). Neurotoxicity may manifest as both acute and delayed complications, which is particularly a concern for long-term survivors. Patients may experience a wide range of neurotoxic syndromes, ranging from neuro-vascular complications and focal neurological deficits to generalized neurological decline with cognitive impairment, cortical atrophy and white matter abnormalities. Along with the use of more aggressive and combined treatment modalities and prolonged survival of cancer patients, neurological complications have been observed with increasing frequency. The mechanisms by which cancer therapy, including chemotherapy and radiation, result in neurological complications, have been poorly understood. Recent studies have now started to unravel the cell-biological basis for commonly seen neurotoxic syndromes and have provided compelling explanations for delayed neurological complications, such as cognitive decline, progressive myelin disruption and brain atrophy.

Concurrent decline of several antioxidants and markers of oxidative stress during combination chemotherapy for small cell lung cancer

OBJECTIVES

To investigate the oxidant effects of adriamycin-containing chemotherapy (CT), we evaluated various antioxidants, total antioxidant capacity (TRAP) and different parameters of oxidative and nitrosative stress during combination CT.

DESIGN AND METHODS

Blood samples were obtained from 16 small cell lung cancer patients at baseline and several times during the first, second and sixth CT cycles.

RESULTS

There were significant decreases in serum urate and serum proteins during all cycles, serum TRAP during the first two cycles, plasma ascorbic acid and serum TBARS during the first cycle, and serum conjugated dienes and plasma alphatocopherol during the last cycle. The baseline levels of tocopherols increased significantly between the first and sixth CT cycles. Higher levels of baseline plasma thiols were associated with better overall survival (p=0.008).

CONCLUSIONS

Adriamycin-containing CT causes significant oxidative stress as implied by reduced levels of protective antioxidants. Long-term CT treatment seems to enhance lipid peroxidation.

The effect of doxorubicin on rats that received toxic and carcinogenic benzo(a)pyrene

Benzo(a)pyrene (B(a)P) is a polycyclic aromatic hydrocarbon with carcinogenic and toxic effects. Doxorubicin is a DNA-interacting drug widely used in chemotherapy. In the present study we investigated the effects of doxorubicin on rats that received benzo(a)pyrene. Sprague-Dawley male rats, 3-4 months old, were divided into 5 groups (n=9 per group). Group 1 (controls) received normal saline intraperitoneally (i.p.) and intragastrically (i.g.), Group 2 (controls) similarly received corn oil i.p. and i.g., Group 3 received corn oil soluble benzo(a)pyrene (10mg/kg b.wt every 10 days for 40 days), Group 4 received doxorubicin (4 mg i.p. on 3 consecutive days), Group 5 received doxorubicin for 3 days (as in group 4) followed by benzo(a)pyrene as in group 3. After twenty-four hours urine samples were collected, heart blood, liver and kidney tissue samples were obtained. Biochemical data were evaluated on urine and blood; liver and kidney tissue samples were investigated histologically. Uric acid, urine creatinine, creatine clearance, urea nitrogen, serum creatinine values, serum glutamic oxaloacetic transaminase (SGOT, AST), serum glutamic pyruvic transaminase (SGPT, ALT), alkaline phosphatase (ALP, AP), superoxide dismutase (SOD), catalase (CAT) activities and malondialdehyde (MDA) levels were significantly different in the 3rd group compared with control groups. Most of the parameters group 5 were statistically similar to control values. Histological appearance of the liver and the kidney tissue samples supported the improvement in the 5th group. The result of our study indicated that liver and kidney functions impaired with benzo(a)pyrene may be partially restored by doxorubicin.

Candidate mechanisms for chemotherapy-induced cognitive changes

The mechanism(s) for chemotherapy-induced cognitive changes are largely unknown; however, several candidate mechanisms have been identified. We suggest that shared genetic risk factors for the development of cancer and cognitive problems, including low-efficiency efflux pumps, deficits in DNA-repair mechanisms and/or a deregulated immune response, coupled with the effect of chemotherapy on these systems, might contribute to cognitive decline in patients after chemotherapy. Furthermore, the genetically modulated reduction of capacity for neural repair and neurotransmitter activity, as well as reduced antioxidant capacity associated with treatment-induced reduction in oestrogen and testosterone levels, might interact with these mechanisms and/or have independent effects on cognitive function.