Lipoperoxides as an index of free radical activity in bone marrow transplant recipients. Preliminary observations

Supplementation with Oral Vitamin C Prior to and during Myeloablative Chemotherapy and Autologous Haematopoietic Stem Cell Transplantation: A Pilot Study

Chemotherapy-related side effects are common in patients undergoing myeloablative chemotherapy and haematopoietic stem cell transplantation. Some, such as oral mucositis, are believed to be due to enhanced oxidative stress and inflammation. Vitamin C, a potent antioxidant with anti-inflammatory properties, becomes severely depleted following myeloablative chemotherapy. The aim of our study was to assess the feasibility and efficacy of oral vitamin C supplementation to restore and maintain adequate vitamin C concentrations in patients undergoing myeloablative chemotherapy and stem cell transplantation. We carried out a pilot randomized controlled trial in 20 patients with myeloma and lymphoma. Placebo or vitamin C tablets (1 g twice daily) were initiated one week prior to transplantation and continued for 4 weeks post-transplantation. Blood samples were collected weekly for analysis of plasma vitamin C concentrations using high-performance liquid chromatography. The patients’ symptoms and quality of life parameters were monitored using the World Health Organization oral toxicity scale and the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ). Pre-supplementation with oral vitamin C doubled vitamin C concentrations relative to placebo by day 0 (median 61 vs. 31 µmol/L), with 60% of those in the vitamin C group achieving concentrations ≥ 50 µmol/L, compared with only 10% in the placebo group. Following chemotherapy and transplantation, significance between the vitamin C and placebo groups was lost by day 7, with only 30% of the patients in the vitamin C group having plasma concentrations ≥ 50 µmol/L. This was partly due to intolerance of the oral intervention due to nausea/vomiting and diarrhoea (40% of the participants in each group). Oral mucositis was also observed in 40% of the participants at day 7 or 14. Overall, our study showed that whilst short-term oral vitamin C pre-supplementation was able to restore adequate vitamin C status by day 0, ongoing supplementation could not maintain adequate vitamin C concentrations following chemotherapy and transplantation. Thus, intravenous vitamin C should be trialled as this bypasses the gastrointestinal system, negating intolerance issues and improving bioavailability of the vitamin.

Vitamin requirements during stem cell transplantation: a systematic review

Patients undergoing stem cell transplantation (SCT) are at high risk of malnutrition during the acute post-transplantation period. This systematic review aimed to collate and analyse the evidence for vitamin requirements post-SCT. A systematic search of five databases was conducted to include studies published until March 2021. The review utilised the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) framework. Inclusion criteria consisted of adults undergoing SCT who received vitamin supplementation or had their vitamin levels monitored up to 100 days post-SCT. Studies with paediatric patients or those that looked at vitamin derivates such as folinic acid were excluded. Main outcomes included vitamin deficiency and relevant clinical outcomes. Eleven studies (n = 11) were eligible for inclusion with five rated as neutral quality and six as positive quality. Five studies focused on allogenic SCT, two on autologous SCT and the remaining included a mix of both. Eight studies monitored vitamins levels post-SCT, and seven studies provided vitamin supplementation. Three studies (one provided supplementation) found a high prevalence of vitamin D deficiency (23-60%) prior to SCT. Findings indicate an unclear association between vitamin deficiency and post-SCT complications including acute graft-versus-host-disease, oral mucositis, and mortality. The GRADE certainty of evidence across these outcomes was low or very low. It is unclear if supplementation is needed during SCT, though assessing vitamin D levels prior to transplant should be considered. Further large observational studies or randomised control trials are required to establish vitamin requirements and guide supplementation protocols during SCT.

Population Pharmacokinetic Analysis of N-Acetylcysteine in Pediatric Patients With Inherited Metabolic Disorders Undergoing Hematopoietic Stem Cell Transplant

N-acetylcysteine (NAC) has been used in patients with cerebral adrenoleukodystrophy as an antioxidant agent in association with hematopoietic stem cell transplant (HSCT). However, an understanding of the pharmacokinetic characteristics of intravenous NAC dosing in these patients is limited. If and how NAC pharmacokinetics change following the transplant is unknown. Toward that end, a total of 260 blood samples obtained from 18 pediatric patients with inherited metabolic disorders who underwent HSCT were included in a population pharmacokinetic analysis using nonlinear mixed-effects modeling. NAC clearance (CL) and volume of distribution (V) were explored on 3 occasions: -7, +7, and +21 days relative to transplant. Additionally, the effect of transplant procedure on NAC disposition was explored by accounting for between-occasion variability. The covariate OCC was modeled as a fixed-effect parameter on CL and/or V1. A 2-compartment model adequately described the pharmacokinetics of total NAC. Weight-based allometric scaling on pharmacokinetic parameters was assumed using standard coefficients. Estimates for CL, central (V1), and peripheral volume (V2), and intercompartment clearance were 14.7 L/h, 23.2 L, 17.1 L, 3.99 L/h, respectively, for a 70-kg person. The data only supported between-subject variability in CL (12%) and V1 (41%). Residual variability was estimated to be 16%. HSCT did not change CL and V1 significantly, and analysis across occasions did not reveal any trends. Pharmacokinetic parameter estimates were in general comparable to those reported previously in different populations. These results suggest that dosing of NAC does not need to be altered following HSCT.

Parenteral high‑dose ascorbate - A possible approach for the treatment of glioblastoma (Review)

For glioblastoma, the treatment with standard of care therapy comprising resection, radiation, and temozolomide results in overall survival of approximately 14-18 months after initial diagnosis. Even though several new therapy approaches are under investigation, it is difficult to achieve life prolongation and/or improvement of patient's quality of life. The aggressiveness and progression of glioblastoma is initially orchestrated by the biological complexity of its genetic phenotype and ability to respond to cancer therapy via changing its molecular patterns, thereby developing resistance. Recent clinical studies of pharmacological ascorbate have demonstrated its safety and potential efficacy in different cancer entities regarding patient's quality of life and prolongation of survival. In this review article, the actual glioblastoma treatment possibilities are summarized, the evidence for pharmacological ascorbate in glioblastoma treatment is examined and questions are posed to identify current gaps of knowledge regarding accessibility of ascorbate to the tumor area. Experiments with glioblastoma cell lines and tumor xenografts have demonstrated that high-dose ascorbate induces cytotoxicity and oxidative stress largely selectively in malignant cells compared to normal cells suggesting ascorbate as a potential therapeutic agent. Further investigations in larger cohorts and randomized placebo-controlled trials should be performed to confirm these findings as well as to improve delivery strategies to the brain, through the inherent barriers and ultimately to the malignant cells.

High-Dose Vitamin C in Advanced-Stage Cancer Patients

High-dose intravenously administered vitamin C (IVC) is widely used in cancer patients by complementary and alternative medicine practitioners. The most frequent indications for IVC therapy result from the belief in its effectiveness as a potent anti-cancer agent which additionally enhances chemosensitivity of cancer cells and reduces chemotherapy-related toxicities and fatigue intensity. In this narrative review, we decided to deal with this issue, trying to answer the question whether there is any scientific evidence supporting the rationale for application of high-dose IVC therapy in advanced-stage cancer patients. Although results obtained from preclinical studies demonstrated that millimolar ascorbate plasma concentrations achievable only after IVC administration were cytotoxic to fast-growing malignant cells and inhibited tumor growth as well as prolonged the survival of laboratory animals, such positive effects were not found in human studies with advanced-stage cancer patients. We also have not found the rationale for the use of IVC to increase the effectiveness of chemotherapy and to reduce the chemotherapy-induced toxicity in the above mentioned group. Nevertheless, in palliative care, high-dose IVC might be considered as a therapy improving the quality of life and reducing cancer-related symptoms, such as fatigue and bone pain. However, because of the absence of placebo-controlled randomized trials on IVC efficacy in advanced-stage cancer patients, the placebo effect cannot be excluded.

Protection against chemotherapy- and radiotherapy-induced side effects: A review based on the mechanisms and therapeutic opportunities of phytochemicals

BACKGROUND

Although great achievements have been made in the field of cancer therapy, chemotherapy and radiotherapy remain the mainstay cancer therapeutic modalities. However, they are associated with various side effects, including cardiocytotoxicity, nephrotoxicity, myelosuppression, neurotoxicity, hepatotoxicity, gastrointestinal toxicity, mucositis, and alopecia, which severely affect the quality of life of cancer patients. Plants harbor a great chemical diversity and flexible biological properties that are well-compatible with their use as adjuvant therapy in reducing the side effects of cancer therapy.

PURPOSE

This review aimed to comprehensively summarize the molecular mechanisms by which phytochemicals ameliorate the side effects of cancer therapies and their potential clinical applications.

METHODS

We obtained information from PubMed, Science Direct, Web of Science, and Google scholar, and introduced the molecular mechanisms by which chemotherapeutic drugs and irradiation induce toxic side effects. Accordingly, we summarized the underlying mechanisms of representative phytochemicals in reducing these side effects.

RESULTS

Representative phytochemicals exhibit a great potential in reducing the side effects of chemotherapy and radiotherapy due to their broad range of biological activities, including antioxidation, antimutagenesis, anti-inflammation, myeloprotection, and immunomodulation. However, since a majority of the phytochemicals have only been subjected to preclinical studies, clinical trials are imperative to comprehensively evaluate their therapeutic values.

CONCLUSION

This review highlights that phytochemicals have interesting properties in relieving the side effects of chemotherapy and radiotherapy. Future studies are required to explore the clinical benefits of these phytochemicals for exploitation in chemotherapy and radiotherapy.

Vitamin E and acute graft-versus-host disease after myeloablative allogeneic hematopoietic cell transplantation

OBJECTIVES

Vitamin E has antioxidant and immunomodulatory effects that might influence the development of acute graft-versus-host disease (GvHD). We investigated the association between plasma vitamin E levels and acute GvHD.

METHODS

We studied 115 adults who underwent myeloablative allogeneic hematopoietic cell transplantation between July 2015 and August 2018. Vitamin E was measured by high-performance liquid chromatography in stored plasma samples obtained pre-transplantation at day -23 (±15 days) and post-transplantation at day +28 (±3 days).

RESULTS

Pre-transplantation vitamin E levels were inversely associated with grade II-IV acute GvHD (hazard ratio 0.68 per 10 µmol/L increase, 95% confidence interval [CI]: 0.47-0.98). The association remained after adjustment for known prognostic factors for acute GvHD. Patients with levels below the median had a cumulative incidence of grade II-IV acute GvHD of 46% (CI: 33-59%) versus 21% (CI: 10-32%) in patients with levels above the median. No clear association with non-relapse mortality, relapse, or chronic GvHD was found. Post-transplantation vitamin E levels (measured in 72 [63%] patients) were correlated with pre-transplantation levels (ρ = .31) but were not associated with subsequent grade II-IV acute GvHD.

CONCLUSIONS

High pre-transplantation vitamin E levels were associated with less acute GvHD.

Patients Undergoing Myeloablative Chemotherapy and Hematopoietic Stem Cell Transplantation Exhibit Depleted Vitamin C Status in Association with Febrile Neutropenia

Patients undergoing myeloablative chemotherapy and hematopoietic stem cell transplantation (HSCT) experience profound neutropenia and vulnerability to infection. Previous research has indicated that patients with infections have depleted vitamin C status. In this study, we recruited 38 patients with hematopoietic cancer who were undergoing conditioning chemotherapy and HSCT. Blood samples were collected prior to transplantation, at one week, two weeks and four weeks following transplantation. Vitamin C status and biomarkers of inflammation (C-reactive protein) and oxidative stress (protein carbonyls and thiobarbituric acid reactive substances) were assessed in association with febrile neutropenia. The vitamin C status of the study participants decreased from 44 ± 7 µmol/L to 29 ± 5 µmol/L by week one (p = 0.001) and 19 ± 6 µmol/L by week two (p < 0.001), by which time all of the participants had undergone a febrile episode. By week four, vitamin C status had increased to 37 ± 10 µmol/L (p = 0.1). Pre-transplantation, the cohort comprised 19% with hypovitaminosis C (i.e., <23 µmol/L) and 8% with deficiency (i.e., <11 µmol/L). At week one, those with hypovitaminosis C had increased to 38%, and at week two, 72% had hypovitaminosis C, and 34% had outright deficiency. C-reactive protein concentrations increased from 3.5 ± 1.8 mg/L to 20 ± 11 mg/L at week one (p = 0.002), and 119 ± 25 mg/L at week two (p < 0.001), corresponding to the development of febrile neutropenia in the patients. By week four, these values had dropped to 17 ± 8 mg/L (p < 0.001). There was a significant inverse correlation between C-reactive protein concentrations and vitamin C status (r = -0.424, p < 0.001). Lipid oxidation (thiobarbituric acid reactive substances (TBARS)) increased significantly from 2.0 ± 0.3 µmol/L at baseline to 3.3 ± 0.6 µmol/L by week one (p < 0.001), and remained elevated at week two (p = 0.003), returning to baseline concentrations by week four (p = 0.3). Overall, the lowest mean vitamin C values (recorded at week two) corresponded with the highest mean C-reactive protein values and lowest mean neutrophil counts. Thus, depleted vitamin C status in the HSCT patients coincides with febrile neutropenia and elevated inflammation and oxidative stress.

Intravenous Vitamin C for Cancer Therapy - Identifying the Current Gaps in Our Knowledge

The use of intravenous vitamin C (IVC) for cancer therapy has long been an area of intense controversy. Despite this, high dose IVC has been administered for decades by complementary health care practitioners and physicians, with little evidence base resulting in inconsistent clinical practice. In this review we pose a series of questions of relevance to both researchers and clinicians, and also patients themselves, in order to identify current gaps in our knowledge. These questions include: Do oncology patients have compromised vitamin C status? Is intravenous the optimal route of vitamin C administration? Is IVC safe? Does IVC interfere with chemotherapy or radiotherapy? Does IVC decrease the toxic side effects of chemotherapy and improve quality of life? What are the relevant mechanisms of action of IVC? What are the optimal doses, frequency, and duration of IVC therapy? Researchers have made massive strides over the last 20 years and have addressed many of these important aspects, such as the best route for administration, safety, interactions with chemotherapy, quality of life, and potential mechanisms of action. However, we still do not know the answers to a number of fundamental questions around best clinical practice, such as how much, how often and for how long to administer IVC to oncology patients. These questions point the way forward for both basic research and future clinical trials.

Antioxidants and human diseases

Oxidative stress plays a pivotal role in the development of human diseases. Reactive oxygen species (ROS) that includes hydrogen peroxide, hyphochlorus acid, superoxide anion, singlet oxygen, lipid peroxides, hypochlorite and hydroxyl radical are involved in growth, differentiation, progression and death of the cell. They can react with membrane lipids, nucleic acids, proteins, enzymes and other small molecules. Low concentrations of ROS has an indispensable role in intracellular signalling and defence against pathogens, while, higher amounts of ROS play a role in number of human diseases, including arthritis, cancer, diabetes, atherosclerosis, ischemia, failures in immunity and endocrine functions. Antioxidants presumably act as safeguard against the accumulation of ROS and their elimination from the system. The aim of this review is to highlight advances in understanding of the ROS and also to summarize the detailed impact and involvement of antioxidants in selected human diseases.

Impact of anti-oxidant status and apoptosis on the induction phase of chemotherapy in childhood acute lymphoblastic leukemia

This study aimed to evaluate oxidative stress and apoptosis in childhood acute lymphoblastic leukemia (ALL) at diagnosis and their impact on outcome at the end of the induction phase. Our study included 50 newly diagnosed children with ALL. Evaluation of oxidative stresses (malondialdehyde and total anti-oxidant capacity) was made at diagnosis and at the end of the induction phase. Apoptosis level was determined by fluorometric terminal deoxynucleotidyl transferase dUTP nick end labeling system for patients at diagnosis and after 1 week of treatment. Our study showed that there was increased oxidative stress at diagnosis and after treatment with chemotherapy. Apoptosis index was higher after 1 week of treatment with chemotherapy when compared to its level at diagnosis.

Evaluation of oxidative and antioxidative parameters in pediatric hematopoietic SCT patients

Conditioning regimens preceding hematopoietic SCT (HSCT) usually consist of high-dose chemotherapy. Chemotherapy and radiation therapy are associated with increased formation of free radicals and depletion of critical plasma and tissue antioxidants. Oxidative stress and antioxidant depletion have been described during the transplantation period in HSCT patients. In a limited number of studies, it was observed that the conditioning regimen resulted in oxidative stress and antioxidant depletion in HSCT patients. The objective of this study was to look for further evidence of oxidative stress and antioxidant status in pediatric HSCT patients. In this study, blood samples were collected from 21 pediatric allo-HSCT patients before and after conditioning therapy. Erythrocyte and plasma malondialdehyde (MDA) levels, erythrocyte reduced and oxidized glutathione (GSH) levels, erythrocyte antioxidant enzymes activities, plasma α-tocopherol and β-carotene levels were determined. After high-dose chemotherapy, erythrocyte and plasma MDA levels increased. Reduced GSH levels decreased whereas oxidized GSH levels increased first and then decreased significantly compared with the values before the chemotherapy regimen. It was also observed that catalase, superoxide dismutase and GSH-S-transferase activities decreased, but there was no change in GSH peroxidase activity. On the other hand, plasma α-tocopherol levels increased, but β-carotene levels did not change.

Delta-ALA-D activity is a reliable marker for oxidative stress in bone marrow transplant patients

Background

Bone marrow transplantation (BMT) is often used in the treatment of various diseases. Before BMT, patients are submitted to a conditioning regimen (CR), which consists of the administration of high doses of chemotherapy. The action of many cytostatic drugs involves the overproduction of reactive oxygen species, which together with inadequate antioxidant protection can lead to oxidative stress and this has been implicated in the etiology of various diseases. The objectives of this study were to look for evidence of oxidative stress and also to analyze δ-Aminolevulinato dehydratase (δ-ALA-D) activity as a possible marker of oxidative stress in autologous and allogeneic BMT patients.

Methods

Lipid peroxidation, vitamin C and thiol group levels as well as catalase, superoxide dismutase and δ-ALA-D activity were determined in 37 healthy controls, 13 patients undergoing autologous peripheral blood stem cell transplantation and 24 patients undergoing allogeneic BMT.

Results

We found that patients presented signs of oxidative stress before they were submitted to BMT, during CR and up to 20 days after BMT. There was a decrease in enzymatic and non enzymatic antioxidant defenses, in δ-ALA-D activity, and an increase in lipoperoxidation in the blood of both patient groups.

Conclusion

This study has indicated that autologous and allogeneic BMT are associated with oxidative stress. Moreover, blood δ-ALA-D activity seems to be an additional biomarker of oxidative stress in BMT patients.

Oxidative stress and delta-ALA-D activity in different conditioning regimens in allogeneic bone marrow transplantation patients

OBJECTIVES

To compare different conditioning regimens (CR), in order to determine whether either of them could be less toxic to allogeneic bone marrow transplantation (BMT) patients in terms of oxidative stress and also analyze delta-ALA-D activity as a possible marker of oxidative stress.

DESIGN AND METHODS

Lipid peroxidation, vitamin C, thiol groups levels and catalase, superoxide dismutase and delta-ALA-D activity were determined in 21 healthy controls, 5 patients with fludarabine+cyclophosphamide (FluCy) CR, 12 with busulfan+cyclophosphamide (BuCy) and 4 with cyclophosphamide+total body irradiation (CyTBI).

RESULTS

There were a decrease in enzymatic and non enzymatic antioxidants, in delta-ALA-D activity, and in all CRs and an increase in lipid peroxidation more pronounced in CyTBI CR.

CONCLUSIONS

All CRs promoted oxidative stress in allogeneic BMT patients, but this was more pronounced with CyTBI and delta-ALA-D activity seemed to be an additional biomarker of oxidative stress in these patients.

Measurement of oxidative stress and antioxidant status in acute lymphoblastic leukemia patients

OBJECTIVES

To evaluate the oxidative status and antioxidant defense in patients with acute lymphoblastic leukemia (ALL).

DESIGN AND METHODS

We measured concentrations of plasmatic thiobarbituric acid reactive substances (TBARS), serum protein carbonylation, whole blood catalase (CAT) and superoxide dismutase (SOD) activities, as well as the plasmatic and erythrocyte thiol levels and serum vitamin E concentration. This study was performed on 80 children with ALL divided into 4 groups: just diagnosed, remission induction, remission maintenance and out-of-treatment.

RESULTS

TBARS levels and serum protein carbonylation were higher in ALL patients than in controls and reduced levels of antioxidants were found in these patients.

CONCLUSION

These findings may indicate a possible link between decreased antioxidants and increased levels of cells alterations due to oxidative damage, supporting the idea that there is a persistence of oxidative stress in acute lymphoblastic leukemia.

Green tea polyphenol administration partly ameliorates chemotherapy-induced side effects in the small intestine of mice

The chemotherapeutic agent irinotecan (IT) is highly effective against several types of cancer, although its use is limited due to severe intestinal toxicity. The aim of this study was to evaluate inflammatory and oxidative stress-related processes contributing to small intestinal mucosa damage and to determine the extent to which green tea polyphenols could ameliorate the detrimental effects induced by IT. In Expt. 1, mice were challenged intraperitoneally with IT or saline on 2 consecutive days. For time kinetic measurements, the IT-treated mice were killed at 3, 24, 48, 72, and 96 h after the 2nd dose of IT. Three hours after IT administration, the ileum glutathione concentration dropped significantly. Lipid peroxidation and inflammation, as measured by macrophage inflammatory protein-2 content, myeloperoxidase activity, and nuclear factor-kappaB translocation, were highest between 24 and 48 h after IT treatment. In Expt. 2, green tea polyphenols (1 g/L) were supplied via drinking water for 7 d before and 3 d after treatment with IT. Green tea polyphenols significantly affected the glutathione:glutathione disulfide ratio but not lipid peroxidation, macrophage inflammatory protein-2 levels, myeloperoxidase activity, or nuclear factor-kappaB activation. Our study reveals that IT administration is associated with oxidative stress and inflammation, both occurring simultaneously to IT-induced mucosal damage. The antioxidative defense is affected soon after IT administration. Green tea polyphenols supplied orally protected against oxidation in our experimental model and could be one approach to reducing the risk of IT-induced side effects in the clinical setting.

Effects of melatonin and vitamin E on oxidative-antioxidative status in rats exposed to irradiation

Bone marrow is known to be particularly susceptible to radiation. In this study, the effects of treatment with Vitamin E and melatonin and irradiation-induced lipid peroxidation and its association with antioxidant enzymes in the total bone (bone and bone marrow) and skeletal muscle of rats subjected to total body irradiation was investigated. Wistar-Albino rats were intraperitoneally treated with 100mg/kg Vitamin E or melatonin before exposure to 720cGy irradiation. Control, irradiation, Vitamin E plus irradiation, melatonin plus irradiation groups were sacrificed by decapitation under ether anaesthesia on the 10th day after irradiation exposure. Application of total body irradiation elevated malondialdehyde (MDA) levels in rat skeletal muscle (p<0.001), but glutathione peroxidase (GSH-Px) and catalase activities remained unchanged. Application of Vitamin E with irradiation or melatonin decreased the MDA levels in skeletal muscle (p<0.01), but did not affect the GSH-Px and catalase activity. MDA levels were found elevated in total bone (p<0.001), GSH-Px activity decreased (p<0.001) and catalase activity remained unchanged in the group treated with irradiation. Application of Vitamin E with irradiation increased the GSH-Px activity in total bone (p<0.01), but the activity of MDA and catalase remained unchanged. Treatment of the animals with melatonin concurrent with total body irradiation reduced the degree of lipid peroxidation and elevation in antioxidant enzymes in total bone (p<0.01). We conclude that melatonin may protect the total bone from the damaging effects of irradiation exposure, and its actions protect total bone from oxidative stress. However, protective effects of Vitamin E were not observed in this study.

Role of the GABA-A system in estrogen-induced protection against brain lipid peroxidation in ethanol-withdrawn rats

BACKGROUND

Our previous study showed that 17 beta-estradiol (E2) treatment protects against cerebellar neuronal death and related motor deficits in ethanol-withdrawn rats, in part through the GABAergic system. In this study, we examined the effect of the GABA-A antagonist bicuculline on the neuroprotective effect of E2 by assessing the oxidative marker thiobarbituric acid reactive substances (TBARS) during ethanol withdrawal (EW).

METHODS

Ovariectomized animals that had implants of E2 (EW/E2) or oil (EW/Oil) pellets received liquid ethanol (7.5% w/v) or dextrin for 7 days by gavage. The GABA-A antagonist bicuculline (1.25 mg/kg) was administered (three times a day intraperitoneally) for 4 days starting 3 days before the onset of EW. After testing for overt EW signs at 7 hr of EW, one set of the animals was immediately killed for the collection of the cerebellum, hippocampus, and cortex. The brain homogenates were further processed for TBARS assay to detect TBARS in the presence or absence of FeCl(3). For assessing motor capacity, the other set of animals was tested for the latency to fall from a rotarod after 1 week of EW.

RESULTS

The EW/Oil animals had enhanced endogenous and FeCl(3)-stimulated TBARS levels in the cerebellum and the hippocampus in a manner potentiated by bicuculline but inhibited by E2. Bicuculline counteracted the protective effect of E2 when administered along with E2. Pearson correlation coefficients indicated that the latency to fall from the rotarod covaried with TBARS levels in the cerebellum and the hippocampus.

CONCLUSION

These data suggest that E2 protects against lipid peroxidation in vulnerable brain areas of ethanol-withdrawn rats, in part through the GABAergic system.

Chemotherapy-associated oxidative stress: impact on chemotherapeutic effectiveness

Antineoplastic agents induce oxidative stress in biological systems. During cancer chemotherapy, oxidative stress-induced lipid peroxidation generates numerous electrophilic aldehydes that can attack many cellular targets. These products of oxidative stress can slow cell cycle progression of cancer cells and cause cell cycle checkpoint arrest, effects that may interfere with the ability of anticancer drugs to kill cancer cells. The aldehydes may also inhibit drug-induced apoptosis (programmed cell death) by inactivating death receptors and inhibiting caspase activity. These effects would also diminish the efficacy of the treatment. The use of anti-oxidants during chemotherapy may enhance therapy by reducing the generation of oxidative stress-induced aldehydes.

Estrogen protects against brain lipid peroxidation in ethanol-withdrawn rats

This study examined whether 17beta-estradiol (E2) administration protects against ethanol withdrawal (EW)-associated oxidative insults by assessing oxidative markers thiobarbituric-acid-reacting-substances (TBARS). Ovariectomized rats implanted with E2 (EW/E2) or oil pellets (EW/Oil) received chronic ethanol (7.5% wt./vol., 5 weeks) or control dextrin diet (Dextrin/Oil). At 24 or 48 h of EW, rats were tested for overt EW signs and the cerebellum, hippocampus, and cortex were prepared for TBARS assessment in the presence and absence of FeCl3. For control experiments, we assessed E2 effects on blood ethanol concentrations and TBARS levels during ethanol exposure prior to EW. The EW/Oil group showed enhanced endogenous- and FeCl3-stimulated membrane TBARS levels in the cerebellum and hippocampus in a manner inhibited by E2 treatment. There was a relationship between the severity of EW and elevation of TBARS levels, particularly in the cerebellum. The enhanced TBARS levels at 24 h of EW appeared to diminish at 48 h in the hippocampus, but persisted in the cerebellum. E2 treatment did not alter blood ethanol concentrations and ethanol exposure alone did not enhance TBARS levels. These data suggest that EW rather than ethanol enhances brain lipid peroxidation that is transient and brain-region specific. Estrogens protect against the brain lipid peroxidation in a manner independent of blood ethanol concentrations.

Rust and corrosion in hematopoietic stem cell transplantation: the problem of iron and oxidative stress

Iron overload is a common acute and long-term event associated with autologous and allogeneic hematopoietic stem cell transplantation (HSCT). In a state of iron excess, free iron becomes available to catalyze the conversion of reactive oxygen species (ROS) intermediates such as superoxide anion (O2*-) and hydrogen peroxide (H2O2) to highly toxic free radicals such as hydroxyl radical (OH*). ROS may help to promote chronic liver disease, sinusoidal obstruction syndrome, idiopathic pneumonia syndrome and bacterial, fungal and other opportunistic infections. Phlebotomy has been effectively and safely used to deplete excess iron stores post-HSCT in thalassemic and other iron-overloaded patients. Intracellular iron levels may also be decreased through pharmacologic chelating agents, while antioxidants such as N-acetylcysteine, glutamine (glutathione precursor) and captopril have been shown to replenish glutathione redox potential and scavenge free radicals. A better understanding of the mechanisms involved in the iron-generated pro-oxidant state associated with HSCT will likely lead to reduced toxicity and improved patient outcomes.

Antioxidants and cancer therapy: a systematic review

PURPOSE

Many patients with cancer take antioxidant nutritional supplements during cancer treatment to alleviate treatment toxicities and to improve long-term outcomes, but little is known about the efficacy and safety of antioxidant use during cancer treatment. We reviewed English-language manuscripts published in the biomedical literature, reporting the results of observational studies of antioxidant status and cancer outcomes and of intervention trials of antioxidants among patients receiving chemotherapy with or without radiation for various malignancies.

METHODS

We searched the Medline database and the bibliographies of the retrieved manuscripts, reviews, and books on antioxidants and cancer. The retrieved studies are grouped by study design, malignancy, and end points.

RESULTS

More than 100 citations were retrieved; 52 met our criteria, 31 were observational studies, and 21 were intervention trials. The studies varied in study design, timing of observation/intervention, intervention protocol, malignancy, and anticancer regimen.

CONCLUSION

These inconsistencies preclude a definitive conclusion as to the effect of chemotherapy on antioxidant status in patients undergoing anticancer therapy. However, our review suggests that total antioxidant status (measured by total radical antioxidant parameter) declines during cancer treatment. Adequately powered trials or observational studies among patients with a specific cancer diagnosis receiving a specific treatment regimen are needed to address patients' and physicians' concerns regarding these associations.

Adequate intakes of vitamin E and protein prevent increases of oxidative damage to DNA, lipids, and protein induced by total body irradiation in mice

We examined the influence of the level of dietary protein or vitamin E (VE) on oxidative damage to DNA, lipids, and protein in the liver after total body irradiation (TBI) with X-rays at 1 or 4 Gy. Levels of 8-hydroxydeoxyguanosine, thiobarbituric acid-reactive substances, and protein carbonyls in the liver did not differ among the groups that did not receive TBI. However, oxidative damage to lipids and protein was increased by TBI only in the 1% protein group. DNA damage, lipid peroxidation, or protein oxidation in the liver was increased by TBI in a dose-dependent manner, and the damage was consistently higher in the 1% than in the 20% protein group. In the 1% protein group, a greater decrease in relative spleen weight by TBI was also observed. Concentrations of antioxidants (vitamins C and E and glutathione) in the liver were lower and the concentration of nonheme iron in the liver was higher in the 1% than in the 20% protein group. Mice fed a 1% protein diet became susceptible to TBI-induced oxidative damage, and decreases in antioxidant levels and an increase in iron level were involved in the mechanism of this susceptibility. These results suggest that dietary VE and protein can prevent oxidative damage to DNA, lipid, and protein in mice subjected to TBI. Consumption of a VE-free diet significantly increased 8-hydroxydeoxyguanosine levels in DNA from mice fed the 1% protein diet with TBI, but such changes were not detected in DNA from mice fed the 20% protein diet.

Higher oxidation and lower antioxidant levels in peripheral blood plasma and bone marrow plasma from advanced cancer patients

BACKGROUND

Bone marrow (BM) is an important tissue in the generation of immunocompetent and peripheral blood cells. The precursors of hematopoietic cells in BM undergo continuous proliferation and differentiation and are highly vulnerable to acute and chronic oxidative stress. Little is known about the oxidant and antioxidant status in the BM of untreated patients with nonhematologic tumors. In this study, oxidative stress was evaluated in peripheral blood plasma (PBP) and BM plasma (BMP) from lung carcinoma (LC) and breast carcinoma (BC) patients.

METHODS

The sample included 13 consecutive untreated LC patients, 15 BC patients, and 11 healthy controls. Luminol-dependent chemiluminescence was used to evaluate oxygen radical generation by peripheral blood neutrophils. Lipid oxidation, assessed by 2-thiobarbituric acid-reactive substances (TBARS), and alpha-tocopherol, beta-carotene, and total ubiquinol-10 levels were determined in PBP and BMP.

RESULTS

In LC and BC patients, neutrophil chemiluminescence was higher (128% and 264%, respectively) than in controls (P < 0.05). In cancer patients, TBARS levels were higher in both PBP (51% and 243% for LC and BC patients, respectively) and BMP (66% and 305% for LC and BC patients, respectively) than in plasma from controls (P < 0.01). alpha-Tocopherol and total ubiquinol-10 levels were significantly lower in BMP from BC patients compared with controls. In BC patients, alpha-tocopherol content in PBP was significantly lower than in controls.

CONCLUSIONS

Untreated cancer patients presented an imbalance between oxidant generation and lipid-soluble antioxidant levels in favor of the former.

Lack of effectiveness of short-term intravenous micronutrient nutrition in restoring plasma antioxidant status after surgery

BACKGROUND AND AIMS

Many patients recovering from surgery may be in a state of negative antioxidant balance. For those whose postoperative nutritional requirements are provided intravenously, this may not be adequate for antioxidant repletion. This study was undertaken to assess the total antioxidant status of these patients peri-operatively and prior to beginning intravenous nutrition (IVN), and to determine the adequacy of IVN, including daily micronutrients, in maintaining or restoring antioxidant status in the post-operative period.

METHODS

Plasma total antioxidant status (TAS) was measured in 30 patients who were fed by standard IVN following surgery. Additionally, the 'antioxidant gap' (AOG, a measure of the contribution of antioxidants other than albumin and urate) was calculated. Blood samples were taken on beginning IVN and daily for the duration of IVN, which lasted for up to 26 days.

RESULTS

Prior to IVN, 20 of the 30 patients had a plasma TAS below the reference range and 15 of these 20 remained deficient even after IVN of up to 19 days. A further 3 patients became deficient whilst on IVN. When the group of patients who were deficient was compared with the group who were not, it was found that this difference was predominantly due to a difference in the AOG, (518 (115) v 709 (68) micromol/L (mean (SD)), P<0.0001). The groups did not differ in terms of age, C-reactive protein level, duration of IVN or daily thiol intake/Kg body weight.

CONCLUSIONS

The difference in the gap antioxidants was thought to be due to their utilization in opposing the extra oxidative burden of surgery. Consideration of the antioxidant provision of standard IVN, principally the thiol-containing amino acids, ascorbate, alpha -tocopherol and trace elements suggests that this is insufficient to counter the sum of the pre-existing oxidative stress and the additional oxidative burden imposed by the surgery.

Different onsets of oxidative damage to DNA and lipids in bone marrow and liver in rats given total body irradiation

We examined time-dependent changes in antioxidant vitamins and oxidative damage to DNA and lipids in the bone marrow, liver, and plasma of rats given total body irradiation (TBI) with X-rays at 3 Gy. The oxidative damage to DNA and lipids was evaluated by measuring increases of 8-hydroxydeoxyguanosine (8OHdG) in DNA and 4-hydroxy-2-nonenal (HNE), respectively. After the TBI, marked increases in 8OHdG and HNE were detected at 3 to 5 h in the bone marrow, while gradual increases in these parameters were detected after a few days in the liver. These changes in 8OHdG and HNE were well correlated within each tissue. In the bone marrow, levels of both vitamin C and vitamin E were decreased by the TBI; however, the changes in vitamin C were earlier and greater than those in vitamin E. In the liver, the level of vitamin C did not decrease, but that of vitamin E decreased due to the TBI. Changes in HNE, vitamin C, and vitamin E in the plasma were similar to those in the liver. Within each tissue, the time of decrease in antioxidants was almost the same as that of the increase in oxidative damage. An increase in total iron due to the TBI was also detected in these tissues. In particular, the total iron in the bone marrow was markedly increased at a few hours after the TBI, with a slight increase in transferrin and no increase in ferritin. Exposure studies performed on cells or isolated DNA showed that an increase in 8OHdG was detected immediately after irradiation at more than 100 Gy in bone marrow cells and at less than 10 Gy in isolated DNA, suggesting that an increase in 8OHdG is undetectable even in bone marrow immediately after the TBI at 3 Gy. These results indicate that the onset of oxidative damage to DNA and lipids was delayed after TBI at 3 Gy, that it was quite different in the bone marrow and the liver, and that an increase in iron and decrease in antioxidant vitamins were involved in the mechanism of oxidative damage.

Nutrient support in hematopoietic cell transplantation

High-dose cytoreduction and hematopoietic stem cell infusion form the basis for treatment of hematologic cancers, defects or failure of hematopoiesis, and some solid tumors. As an antitumor therapy, allogeneic hematopoietic cell transplantation (HCT) is superior to autologous HCT by induction of a graft-vs-tumor effect. However, recipients of allografts suffer higher transplant-related mortality owing to graft-vs-host disease (GVHD). Nutrition support research must recognize that HCT is a heterogeneous modality whose short and long-term outcomes are affected by transplant type, preparative regimens, diagnosis, disease stage, age, and nutritional status. The field of HCT will diversify further as lower dose cytoreduction and mixed chimerism grafts allow expansion of the technique to older patients and to other diseases.

Dietary antioxidants during cancer chemotherapy: impact on chemotherapeutic effectiveness and development of side effects

Several studies suggest that dietary supplementation with antioxidants can influence the response to chemotherapy as well as the development of adverse side effects that results from treatment with antineoplastic agents. Administration of antineoplastic agents results in oxidative stress, i.e., the production of free radicals and other reactive oxygen species (ROS). Oxidative stress reduces the rate of cell proliferation, and that occurring during chemotherapy may interfere with the cytotoxic effects of antineoplastic drugs, which depend on rapid proliferation of cancer cells for optimal activity. Antioxidants detoxify ROS and may enhance the anticancer effects of chemotherapy. For some supplements, activities beyond their antioxidant properties, such as inhibition of topoisomerase II or protein tyrosine kinases, may also contribute. ROS cause or contribute to certain side effects that are common to many anticancer drugs, such as gastrointestinal toxicity and mutagenesis. ROS also contribute to side effects that occur only with individual agents, such as doxorubicin-induced cardiotoxicity, cisplatin-induced nephrotoxicity, and bleomycin-induced pulmonary fibrosis. Antioxidants can reduce or prevent many of these side effects, and for some supplements the protective effect results from activities other than their antioxidant properties. Certain side effects, however, such as alopecia and myelosuppression, are not prevented by antioxidants, and agents that interfere with these side effects may also interfere with the anticancer effects of chemotherapy.

Plasma antioxidant status after high-dose chemotherapy: a randomized trial of parenteral nutrition in bone marrow transplantation patients

BACKGROUND

Chemotherapy and radiation therapy result in increased free radical formation and depletion of tissue antioxidants. It is not known whether parenteral nutrition (PN) administered during bone marrow transplantation (BMT) supports systemic antioxidant status.

OBJECTIVE

The aims of the study were to determine 1) whether high-dose chemotherapy decreases concentrations of major circulating antioxidants in patients undergoing BMT and 2) whether administration of standard PN maintains systemic antioxidant concentrations compared with PN containing micronutrients and minimal lipids alone.

DESIGN

Twenty-four BMT patients were randomly assigned to receive either standard PN containing conventional amounts of dextrose, amino acids, micronutrients, and lipid (120 kJ/d) or a solution containing only micronutrients (identical to those in standard PN) and a small amount of lipid (12 kJ/d). Plasma antioxidant status was measured before conditioning therapy and serially at days 1, 3, 7, 10, and 14 after BMT.

RESULTS

Plasma glutathione (GSH) and alpha- and gamma-tocopherol concentrations decreased and the GSH redox state became more oxidized after conditioning chemotherapy. Plasma cysteine concentrations were unchanged, whereas cystine concentrations increased. Plasma vitamin C and zinc concentrations and GSH peroxidase activity increased over time. Plasma alpha-tocopherol concentrations were lower in patients given standard PN. There were no differences in other plasma antioxidants between groups.

CONCLUSIONS

A significant decline in GSH-glutathione disulfide, cysteine-cystine, and vitamin E status occurs after chemotherapy and BMT. Standard PN does not improve antioxidant status compared with administration of micronutrients alone. Further evaluation of PN formulations to support patients undergoing high-dose chemotherapy and BMT are needed.

Impaired plasma antioxidative defense and increased nontransferrin-bound iron during high-dose chemotherapy and radiochemotherapy preceding bone marrow transplantation

To analyze the effects of radiochemotherapy on the pro-oxidative/antioxidative balance in plasma, we measured the total radical antioxidant parameter of plasma (TRAP) and single plasma antioxidants (uric acid, sulfhydryl groups, alpha-tocopherol, ubiquinone-10/total coenzyme-Q10 ratio, ascorbate, and bilirubin) every 12 h during high-dose chemotherapy and radiochemotherapy preceding bone marrow transplantation (BMT). Nontransferrin-bound iron (NTBI) was monitored as a potential pro-oxidant. Plasma levels of polyunsaturated fatty acids (PUFA) were measured as substrates, and thiobarbituric acid-reactive substances (TBARS) were measured as products of lipid peroxidation. Allantoin was analyzed as the product of uric acid oxidation. Patients receiving busulfan, VP-16, and cyclophosphamide (BU/VP/CY) (n = 8) were compared with those receiving total body irradiation in addition to VP-16 and cyclophosphamide (TBI/VP/CY) (n = 8). TRAP values were within the normal range before therapy and decreased after BU/VP/CY by 37% (p <. 02) and after TBI/VP/CY by 39% (p <.02). During TBI and after VP-16, a temporary increase in TRAP values occurred, which was not related to changes in individual antioxidants. In vitro experiments confirmed that VP-16 had an antioxidative effect. The concentration of uric acid declined in both groups and correlated with TRAP (BU/VP/CY: r =.80, p <.001; TBI/VP/CY: r =.84, p <.001). Levels of NTBI, which is normally not found in plasma, increased rapidly during conditioning therapy (p <.02 in both groups) and correlated inversely with TRAP (weighted intraindividual Spearman rank correlation coefficient for both groups: NTBI and TRAP: r = -.59, p <.001) and PUFA (in the radiochemotherapy group: r = -.67, p <.001). Whereas PUFA declined (p <.02 in both groups), TBARS increased (p <. 05 in both groups). Furthermore, an increase of allantoin and ubiquinone-10/total coenzyme-Q10 ratio in the BU/VP/CY group was found (allantoin: p <.02; ubiquinone-10/total coenzyme-Q10 ratio: p <.05). Antioxidants only partially recovered to baseline values until day 14 after BMT. Our findings indicate oxidative stress after high-dose radiochemotherapy and suggest a contribution of NTBI therein.

Oxidative stress and NF-kappaB activation: correlation in patients following allogeneic bone marrow transplantation

Although in vitro data has linked reactive oxygen species (ROS) to activation of nuclear factor kappaB (NF-kappaB), little data exist regarding this relationship in human disease. We hypothesized that bone marrow transplantation (BMT) would impart a degree of oxidative stress that might lead to in vivo activation of the redox-sensitive transcription factor NF-kappaB. Because NF-kappaB regulates transcription of many proinflammatory mediators, we reasoned that activation of NF-kappaB might contribute to the development of transplant-related complications. To evaluate NF-kappaB activation in humans, we measured NF-kappaB binding activity in nuclear extracts of bronchoalveolar lavage (BAL) cells obtained before and after allogeneic bone marrow transplantation (BMT) in 7 patients. Changes in BAL cell NF-kappaB binding activity were compared with changes in urinary F2-isoprostane concentration, an indicator of in vivo free radical-catalyzed lipid peroxidation. Although the extent of in vivo lipid peroxidation has substantial interindividual variability over time, we found a strong correlation between the pre/post-BMT ratio of urinary isoprostane concentrations and pre/post-BMT ratio of NF-kappaB binding activity in BAL cells, R = 0.96, p = 0.0005). This correlation is selective, because no relationship was found between the transcription factor CREB and urinary F2-isoprostane excretion. Although limited by the small number of patients studied, our data link oxidant stress to NF-kappaB activation in human alveolar macrophages following BMT. It is possible that such interactions may contribute to the clinical course after BMT by affecting transcription of proinflammatory genes.

Nontransferrin-bound iron in serum of patients receiving bone marrow transplants

Nontransferrin-bound iron (NTBI) and other parameters of iron status were measured in 40 patients undergoing bone marrow transplantation (BMT) prior to conditioning therapy (between day -10 and -7), at the time of BMT (day 0), and 2 weeks later (day + 14). Serum iron and transferrin saturation values were normal before conditioning therapy. At day 0 serum iron values were high and median transferrin saturation was 98% (changes in the values of both serum iron and transferrin saturation, p < .0001). Transferrin saturation values were still elevated 2 weeks posttransplant (day +14 vs. baseline values, p = .0001). Starting at low NTBI levels pretransplant (median 0.4 micromol/l, range 0-4.2 micromol/l, controls: < or = 0.4 micromol/l), all patients revealed high levels on day 0 (median 4.0 micromol/l, range 1.9-6.9 micromol/l, p < .0001) and 2 weeks posttransplant (median 2.7 micromol/l, range 0-6.2 micromol/l, p < .0001). These observations indicate that the plasma iron pool in patients undergoing BMT increases to a level at which the normal ability to sequestrate iron becomes exhausted and considerable amounts of NTBI appear in serum. This "free" form of iron can mediate the production of reactive oxygen species and may cause organ toxicity in the early posttransplantation period.