Red Blood Cell Glutathione Research Articles

Effect of extremely low frequency magnetic field on antioxidant activity in plasma and red blood cells in spot welders

The purpose of this study was to determine a possible relation between exposure to extremely low frequency magnetic field (ELF-MF) and the human antioxidant activity. The total serum antioxidant status (TAS), red blood cells (RBCs) glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured in 46 spot welders who were occupationally exposed to ELF-MF (magnetic field strength = 8.8-84 microTesla (microT), frequency = 50 Hertz (Hz) and electric field strength = 20-133 V/m). The results were compared with a nonexposed ELF-MF control group. The correlation between magnetic field strength and antioxidant activity in RBCs and plasma was then assessed. No significant differences in TAS levels were observed (P value = 0.065). However, in RBCs of exposed group, a significant decrease in SOD and GPX activities was observed (P value = 0.001 and 0.003, respectively). This decrease was measured as 22 and 12.3%, respectively. Furthermore, a significant negative correlation between SOD/GPX activities and magnetic field intensity was observed (coefficients of SOD: -0.625, significance: 0.0001 and coefficients of GPX: -0.348, significance: 0.018). The results of this study indicate that ELF-MF could influence the RBC antioxidant activity and might act as an oxidative stressor. Intracellular antioxidant enzymes such as SOD and GPX were found to be the most important markers involving in this process. The influence of magnetic field on the antioxidant activity of RBCs might occur even at the recommended levels of exposure.

Effect of One‐year Oral α‐Tocopherol Administration on the Antioxidant Defense System in Hemodialysis Patients

Oxidative stress is increased in hemodialysis (HD) patients and contributes to the increased morbidity and mortality in this population. Vitamin E is an antioxidant agent. In the present study the effect of prolonged oral alpha-tocopherol administration on the antioxidant defense system was evaluated. The antioxidant factors plasma total antioxidant status (TAS), red blood cell superoxide dismutase (SOD) activity and glutathione peroxidase (GPX) activity were evaluated with spectrometry in 27 HD patients. Measurements were performed before and after oral administration of alpha-tocopherol at a dose of 500 mg/d for a one-year period. Twenty HD patients received a placebo and 22 healthy volunteers served as controls. TAS was increased in HD patients. No difference was detected in SOD and GPX activity between HD patients and healthy volunteers. Tocopherol administration induced a significant decrease in TAS and SOD activity. Levels of GPX activity remained unaffected. All the evaluated factors remained stable in the HD patients receiving a placebo. Prolonged oral alpha-tocopherol administration in HD patients induces a decrease in some components of the antioxidant defense system, raising the possibility for a pro-oxidative role of vitamin E. Vitamin E is an antioxidant agent, but it is also known to have pro-oxidant action under special conditions that can be encountered in HD patients.

Lipoperoxidation and Protein Oxidative Damage Exhibit Different Kinetics During Septic Shock

Septic shock (SS)-related multiorgan dysfunction has been associated with oxidative damage, but little is known about the temporal damage profile and its relationship to severity. The present work investigated prospectively 21 SS patients. Blood samples were obtained at diagnosis, 24, 72 hours, day 7, and at 3 months. At admission, thiobarbituric acid reactive substances (TBARSs), plasma protein carbonyls, plasma protein methionine sulfoxide (MS), ferric/reducing antioxidant power (FRAP), total red blood cell glutathione (RBCG), uric acid (UA), and bilirrubin levels were increased (P < .05). Total radical—trapping antioxidant potential (TRAP) and vitamin-E were similar to controls, and vitamin-C was decreased (P < .05). During evolution, TBARS and RBCG increased (P < .001), vitamin-E levels remained stable, whereas plasma protein carbonyls and MS, TRAP, vitamin-C, reduced glutathione, and UA levels decreased (P < .006). After 3 months, plasma protein carbonyls and MS persisted elevated. More severe patients exhibited higher TBARS, TRAP, FRAP, vitamin-C, UA, and bilirrubin levels. Our results suggest early and persistent oxidative stress during septic shock and a correlation between increasing levels of lipoperoxidation and sepsis severity.

Pyruvate Kinase Is Protected by Glutathione-Dependent Redox Balance in Human Red Blood Cells Exposed to Reactive Oxygen Species

To determine the antioxidant role of glutathione (GSH) in human red blood cells (RBCs), we investigated the effect of disrupting GSH homeostasis on the oxidative modification of thiol-dependent enzymes by exposure to tert-butyl hydroperoxide (BHP). When hemolysate was incubated with BHP, significant decreases in enzyme activity were observed. However, the inactivation did not occur in intact RBC suspensions that were exposed to BHP. In this study, we used two independent treatments aimed at decreasing the level of reduced form of GSH, pre-incubation with a glutathione reductase inhibitor or glucose-free medium to examine the influences of preventing GSH-dependent antioxidant and reactivation activity on thiol-dependent enzyme. Pyruvate kinase (PK) activity clearly decreased along with depletion of GSH compared to other glycolytic enzyme activities by BHP exposure in RBCs. The addition of GSH, but not glucose, before BHP exposure completely prevented the inactivation of PK in hemolysate; however, partial reactivation of inactivated PK was observed by post-addition of both GSH and glutaredoxin at an early stage during BHP exposure. Moreover, hydroxyl radicals but not hydrogen peroxide inactivated PK. These results suggest that PK is highly susceptible to radicals and that GSH is essential to protect PK activity by not only directly scavenging radicals but also by systematically reactivating oxidized enzyme in human RBCs.

Cognitive functions and the antioxidant system in phenylketonuric patients.

The authors studied the relationship between the antioxidant system and cognitive functions in a group of 36 early and continuously treated phenylketonuric (PKU) patients (mean age=9.7 years) and 29 controls. The authors measured antioxidant cofactors and free radical damage markers in plasma (selenium, retinol, tocopherol, coenzyme Q10, malondialdehide) and antioxidant enzymes in red blood cells (glutathione peroxidase, catalase, superoxide dismutase). The authors used neuropsychological tests to screen for several cognitive functions. PKU patients showed significantly lower values of selenium, coenzyme Q10, and catalase, and significantly higher levels of malondialdehide. PKU patients showed a significantly negative correlation between plasma selenium concentrations and several Conner's Continuous Performance Test measures (more omission errors, fluctuating attention and inconsistency of response times, and slowing reaction time as the test progressed). Selenium deficiency was thus associated with a worsened performance on the Conner's Continuous Performance Test among PKU patients. In conclusion, it is important not only to control blood Phe levels in PKU but also other nutritional components such as selenium. Selenium status seems to be associated with attention functions in these PKU patients.

Puerto Rican Child with Combined Heterozygocity for Hemoglobin S and Porto Alegre.

Hemoglobin S is the most common abnormal hemoglobin detected in newborn screening in Puerto Rico. The purpose of this report is to present laboratory and clinical data from a newborn proven to have combined heterozygocity for hemoglobin S and a very rare hemoglobin. Abnormal newborn screening results using isoelectric focusing prompted us to further study an infant with an unknown hemoglobin. Testing with cellulose acetate and citrate agar electrophoresis revealed that this patient had, besides hemoglobin S, a rare fast moving band. We consulted the Haemoglobinopathy Screening Service at St. James's University Hospital in Leeds, UK where our patient's hemoglobin was identified as hemoglobin Porto Alegre by means of mass spectrometry. DNA sequencing at the molecular genetics laboratory in the Medical Sciences Campus, University of Puerto Rico confirmed our patient's hemoglobin to be Hb Porto Alegre. The patient's father was found to be heterozygous for hemoglobin S and her mother a carrier of hemoglobin Porto Alegre. Our patient has been followed-up for the last two years. She has remained asymptomatic, except for usual mild childhood diseases. Laboratory results up to 18 months of age have revealed Hgb 11.4–11.6 g/dl, MCV 87.5 fl, MCH 28.7 pg, reticulocyte count 2%, normal total bilirubin and LDH levels. Hemoglobin Porto Alegre involves a mutation in ß9(A6)Ser→Cys which promotes hemoglobin polymerization via disulfide bonds (Baudin-Creuza 2002). This mutation does not seem to alter hemoglobin function and apparently does not increase tendency for sickling. Tondo (1963) has reported that in vivo hemoglobin Porto Alegre exists in its normal tetrameric form, with no associated hemolysis. Martinez (1977) has suggested that hemoglobin Porto Alegre can exist in its tetrameric functional form by means of high levels of glutathione in red blood cells. Therefore, patients with combined hemoglobin S and Porto Alegre would be expected to be asymptomatic. Hemoglobin Porto Alegre has been documented in a few patients from Brazil, Portugal, Argentina, Cuba, and the Canary Islands. To our knowledge this is the first reported double heterozygote for hemoglobin S and Porto Alegre. We are following our patient closely for the development of any significant hematologic or clinical symptoms.

Vasorelaxation with Garlic? It’s a Gas

Garlic is reputed to have various beneficial effects on health, and its consumption has been correlated with a decrease in several risk factors for cardiovascular disease. Noting that garlic is rich in organosulfur compounds and that hydrogen sulfide (H 2 S), like nitric oxide and carbon monoxide, may act as a gaseous signaling molecule in the cardiovascular system (see Lefer), Benavides et al. investigated the possibility that polysulfide compounds in garlic might provide a source of vascular H 2 S. Using a polarographic H 2 S sensor, they showed that addition of garlic juice to human red blood cells (RBCs) elicited H 2 S production. Glucose, which enabled the maintenance of the pool of reduced RBC glutathione, promoted sustained production of H 2 S in the presence of garlic; moreover, glutathione plus garlic produced H 2 S even in the absence of RBCs. Experiments with membrane-permeant and -impermeant thiol-blocking reagents indicated that H 2 S production involved exofacial RBC membrane thiols, as well as intracellular thiols. H 2 S produced in the presence of either garlic or garlic-derived polysulfides elicited relaxation of precontracted rat aortic rings, an effect that did not require a functional endothelium. Thus, the authors propose that garlic produces beneficial vasoactive effects by promoting the production of H 2 S. G. A. Benavides, G. L. Squadrito, R. W. Mills, H. D. Patel, T. S. Isbell, R. P. Patel, V. M. Darley-Usmar, J. E. Doeller, D. W. Kraus, Hydrogen sulfide mediates the vasoactivity of garlic. Proc. Natl. Acad. Sci. U.S.A. 104 , 17977-17982 (2007). [Abstract] [Full Text] D. J. Lefer, A new gaseous signaling molecule emerges: Cardioprotective role of hydrogen sulfide. Proc. Natl. Acad. Sci. U.S.A. 104 , 17907-17908 (2007). [Full Text]

A Probable Causative Factor for an Old Problem: Selenium and Glutathione Peroxidase Appear to Play Important Roles in Epilepsy Pathogenesis

Only recently has it become known that oxidative stress and generation of reactive oxygen species are the cause and the consequence of epileptic seizures. Due to the protective role of selenium (Se) and selenoproteins against oxidative damage and the ability to promote neuronal cell survival, we compared serum selenium level and red blood cell Glutathione peroxidase activity (RBC GPx) between epileptic and healthy children. In a case control study, 53 epileptic children were compared with 57 healthy children in the same age and community of residence. Serum Se and RBC GPx activity were measured with an atomic absorption spectrophotometry and Cayman standard glutathione assay kit, respectively. The mean (+/-standard deviation) of serum Se was 72.90 microg/L (+/-22.20) and 86.00 microg/L (+/-15.00) in patient and control groups, respectively. For RBC GPx activity the mean (+/-standard deviation) was 440.57 nmol/min/ml (+/-264.00) and 801.00 nmol/min/ml (+/-267.00) in patient and control groups, respectively. Statistical analysis showed a significant lower means of serum Se and RBC GPx activity in patient group compared to that of healthy control group (p < 0.001). Lower serum Se and RBC GPx activity in epileptic patients compared to healthy children may support the proposed crucial role of Se and GPx activity in the pathogenesis of epilepsy. However, RBC GPx activity in the case of selenium deficiency could not be a sensitive and specific indicator of Se status in serum that led us to supplant Se measurement with RBC GPx activity.

Deficiency of Glutathione Peroxidase-1 Accelerates the Progression of Atherosclerosis in Apolipoprotein E-Deficient Mice

We have recently demonstrated that activity of red blood cell glutathione peroxidase-1 is inversely associated with the risk of cardiovascular events in patients with coronary artery disease. The present study analyzed the effect of glutathione peroxidase-1 deficiency on atherogenesis in the apolipoprotein E-deficient mouse. Female apolipoprotein E-deficient mice with and without glutathione peroxidase-1 deficiency were placed on a Western-type diet for another 6, 12, or 24 weeks. After 24 weeks on Western-type diet, double-knockout mice (GPx-1(-/-)ApoE(-/-)) developed significantly more atherosclerosis than control apolipoprotein E-deficient mice. Moreover, glutathione peroxidase-1 deficiency led to modified atherosclerotic lesions with increased cellularity. Functional experiments revealed that glutathione peroxidase-1 deficiency leads to increased reactive oxygen species concentration in the aortic wall as well as increased overall oxidative stress. Peritoneal macrophages from double-knockout mice showed increased in vitro proliferation in response to macrophage-colony-stimulating factor. Also, we found lower levels of bioactive nitric oxide as well as increased tyrosine nitration as a marker of peroxynitrite production. Deficiency of an antioxidative enzyme accelerates and modifies atherosclerotic lesion progression in apolipoprotein E-deficient mice.

Red blood cell and plasma glutathione peroxidase activities and selenium concentration in patients with chronic kidney disease: a review.

The metabolism of oxygen in aerobic organisms leads to generation of reactive oxygen species (ROS). These entities are able to oxidize almost all classes of macromolecules, including proteins, lipids and nucleic acids. The physiological level of ROS is usually regulated by antioxidant defense mechanisms. There are at least three groups of antioxidant enzymes: superoxide dismutases, catalases and glutathione peroxidases (GSH-Pxs) which neutralize ROS. The trace elements (copper, zinc and selenium) bound to the active sites of the above listed enzymes play an important role in the antioxidant defense system. In mammals, a major function of selenium (Se) and Se-dependent GSH-Pxs is to protect cells from oxidative stress. Selenium concentrations and GSH-Px activities are altered in blood components of chronic kidney disease (CKD) patients. The Se level is frequently lower than in healthy subjects and the concentration very often decreases gradually with advancing stage of the disease. Studies on red cell GSH-Px activity in CKD patients reported its values significantly lower, significantly higher and lower or higher, but not significantly as compared with healthy subjects. On the other hand, all authors who studied plasma GSH-Px activity have shown significantly lower values than in healthy subjects. The degree of the reduction decreases gradually with the progression of the disease. High inverse correlations were seen between plasma GSH-Px activity and creatinine level. A gradual decrease in plasma GSH-Px activity in CKD patients is due to the fact that this enzyme is synthesized predominantly in the kidney and thus the impairment of this organ is the cause of the enzyme's lower activity. Se supplementation to CKD patients has a slightly positive effect in the incipient stage of the disease, but usually no effect was observed in end-stage CKD. Presently, kidney transplantation is the only treatment that may restore plasma Se level and GSH-Px activity in patients suffering from end-stage CKD. A few studies have shown that in kidney recipients, plasma Se concentration and GSH-Px activity are restored to normal values within a period of 2 weeks to 3 months following surgery and thus it can be acknowledged that Se supplementation to those patients has a positive effect on plasma GSH-Px activity.

Integration of nanoporous membranes for sample filtration/preconcentration in microchip electrophoresis

Microfluidic devices integrating membrane-based sample preparation with electrophoretic separation are demonstrated. These multilayer devices consist of 10 nm pore diameter membranes sandwiched between two layers of PDMS substrates with embedded microchannels. Because of the membrane isolation, material exchange between two fluidic layers can be precisely controlled by applied voltages. More importantly, since only small molecules can pass through the nanopores, the integrated membrane can serve as a filter or a concentrator prior to microchip electrophoresis under different design and operation modes. As a filter, they can be used for separation and selective injection of small analytes from sample matrix. This has been effectively applied in rapid determination of reduced glutathione in human plasma and red blood cells without any off-chip deproteinization procedure. Alternatively, in the concentrator mode, they can be used for online purification and preconcentration of macromolecules, which was illustrated by removing primers and preconcentrating the product DNA from a PCR product mixture.

Dynamic Monitoring of Glutathione in Erythrocytes, without a Separation Step, in the Presence of an Oxidant Insult

A method for the quantitative determination of the antioxidant form of glutathione (GSH) in red blood cells (RBCs) is described that does not require separation of the analyte of interest from the complex cellular matrix. The measurement portion of the analysis is performed using fluorescence spectrophotometry after monochlorobimane (a recognized probe for GSH) is added to a mixture containing RBCs and glutathione transferase (GST). This method was employed to determine the GSH concentration (0.042 +/- 0.002 mM) in a solution of 1% RBCs obtained from rabbits (n = 6). When spiked with authentic GSH (0.50 micromol), 99.8% of the GSH was recovered. Addition of GST to the sample mixture enabled most measurements to be made after 5-10 min of reaction time. Importantly, a decrease in GSH was measured upon the addition of a recognized oxidant (diamide) to the RBC sample followed by a subsequent return to normal levels of GSH. The ability of the GSH to recover from the oxidant attack occurred in a dose-dependent manner, requiring 30 and 90 min to recover from oxidant insults of 20 and 40 microM diamide, respectively. The antioxidant capabilities of the GSH were able to be monitored in real time, thus providing a method to dynamically monitor the ability of the RBC to maintain homeostasis in a complex matrix.

High superoxide dismutase and low glutathione peroxidase activities in red blood cells predict susceptibility of lung cancer patients to radiation pneumonitis

Radiation pneumonitis is an unpredictable complication of radiotherapy for lung cancer and a condition which can cause significant morbidity. The ability to identify patients at a high risk of developing pneumonitis is critical, since it will enable the individualization of the treatment plan. Because the cytotoxic effect of radiation is propagated through reactive oxygen species (ROS) and ROS-driven oxidative stress, the role of antioxidant defense systems in radiation pneumonitis was investigated. Using the pneumonitis-sensitive C3H/HeN mice as a model, we demonstrated that the antioxidant response of the lung correlated well with that of red blood cells (RBC). We then proceeded to test whether differences of RBC antioxidant response would predict the pneumonitis development in patients. Superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities and glutathione in RBC were measured at baseline and then weekly for 6 weeks of treatment in 15 eligible patients receiving concurrent chemo-radiotherapy for unresectable stage III NSCLC. Striking differences were found in the antioxidant activities of RBC with respect to the pneumonitis development. Those who developed pneumonitis showed higher SOD and lower GPX activities at baseline compared to those who did not (3.7 vs 6.8 units/mg for median SOD, 16.5 vs 10.7 nmol/min/mg for median GPX). The functional imbalance of SOD and GPX was displayed consistently throughout the treatment period. The sensitivity and specificity of pneumonitis prediction were further increased when the GPX/SOD ratio was analyzed (pretreatment P = 0.0046). Our results provide a strong rationale to monitor SOD and GPX activities of RBC to identify patients who are at risk of developing pneumonitis, and to implement a strategy of increasing the GPX/SOD ratio in order to lower the risk.

Oxidative Stress in Renal Transplant Patients Who Develop Cardiovascular Disease

Cardiovascular disease limits life expectancy of successful renal transplant patients. Reactive oxygen species have been implicated in the development of atherosclerosis, and high levels could be due to increased production or a decrease in antioxidant reserve. Cardiovascular disease in renal transplant recipients could be due to elevated levels of malondialdehyde (an index of levels of reactive oxygen species) and homocysteine and reduced levels of glutathione. Renal transplant recipients with and without cardiovascular disease were studied along with healthy controls. Serum malondialdehyde, plasma homocysteine, and red blood cell glutathione were measured. The results suggest that levels of serum malondialdehyde and plasma homocysteine were higher in patients with or without cardiovascular disease compared with controls; however, the values were similar in both groups of transplant patients. Glutathione levels in red blood cells were similar in all 3 groups. Renal transplant recipients without cardiovascular disease have high levels of oxidative stress and may develop cardiovascular disease with time.

Oxidative Stress Is Decreased in Off-pump Versus On-pump Coronary Artery Surgery

Oxidative stress occurs in patients undergoing coronary artery bypass operation. The aim of this study was to investigate the difference in oxidative stress in off-pump versus on-pump coronary artery bypass surgery. In the present study, in serial blood samples, plasma malondialdehyde (MDA) as index of lipid peroxidation, red blood cells glutathione peroxidase (GPx) and superoxide dismutase (SOD) were measured to compare the extent of oxidative stress in 30 patients undergoing OPCAB (off-pump coronary artery bypass grafting), 12 patients undergoing CABG (on-pump coronary artery bypass grafting) and 18 healthy controls. In CABG group, MDA levels increased significantly from 2.87 +/- 0.62 nmol/mL before anesthesia and 2.87 +/- 0.65 nmol/mL after anesthesia to 3.05 +/- 0.66 nmol/mL after ischemia (p < 0.05). Similarly, SOD levels also elevated significantly from 661.58 +/- 78.70 U/g Hb before anesthesia and 659.42 +/- 81.21 U/g Hb anesthesia induction to 678.08 +/- 75.80 U/g Hb after ischemia (p < 0.01, p < 0.01, respectively). In OPCAB group, only SOD levels increased from 581.73 +/- 86.24 U/g Hb anesthesia induction to 590.90 +/- 88.90 U/g Hb after reperfusion (p < 0.05). Glutathione peroxidase levels were not changed according to blood collection times in both of CABG group or OPCAB group (p > 0.05). Our results show that only mild signs of oxidative stress is found after reperfusion in OPCAB operation compared with CABG operation. Further studies are needed in order to confirm this hypothesis.

Energy restriction but not protein source affects antioxidant capacity in athletes

The primary purpose of this study was to examine the effect of energy restriction on antioxidant capacity in trained athletes. Secondly, our study determined whether dietary protein source influenced the antioxidant response, performance, and immunity. Twenty male cyclists consumed either whey or casein supplement (40 g/day) in addition to their diet for 17 days. All subjects subsequently underwent 4 days of energy restriction using a formula diet (20 kcal/kg) while continuing protein supplementation. Energy restriction caused 2.7 ± 0.3 kg weight loss, increased lymphocyte total glutathione (tGSH) 37%, red blood cell glutathione peroxidase 48%, plasma cysteine 12%, and decreased whole blood reduced to oxidized GSH (rGSH/GSSG) ratio by 52%. The only immunity factor altered by energy restriction was an increase in stimulated phagocytosis (65%). Acute submaximal exercise reduced blood tGSH but increased glutathione peroxidase. Performance of a high intensity cycle test following 45 min of moderate exercise tended to be reduced by energy restriction ( P = 0.06) but was unaffected by protein source. Energy restriction caused a negative nitrogen balance with no difference from dietary protein source. In conclusion, acute energy restriction increased plasma cysteine and several markers of the glutathione antioxidant system in trained athletes. A high cysteine dietary protein source did not influence these responses.

Dang‐Gui Buxue Tang produces a more potent cardioprotective effect than its component herb extracts and enhances glutathione status in rat heart mitochondria and erythrocytes

The effects of pretreatment with Dang-Gui Buxue Tang (DBT, a decoction of Astragali and Angelica roots) and its component herb extracts on myocardial ischaemia-reperfusion (IR) injury were examined in rats ex vivo. DBT and its component herb extracts could protect against myocardial IR injury in a dose-dependent manner. The more potent cardioprotection afforded by DBT pretreatment than that of a mixture of Astragali and Angelica root extracts was associated with a much higher extraction yield of active ingredients from Angelica root in the herbal decoction. The high level of active ingredients might increase their bioavailability after oral administration. DBT pretreatment could enhance myocardial mitochondrial as well as red blood cell (RBC) glutathione status, thereby increasing their resistance to oxidative stress-induced injury in rats. The measurement of RBC glutathione status may serve as a useful index for the antioxidant effect produced by DBT treatment in human subjects.

Effects of Different Grape Formulations on Antioxidative Capacity, Lipid Peroxidation and Oxidative DNA Damage in Aged Rats

In this study, the freeze-dried powders from whole grapes, pomace and juice of Campbell Early (Vitis labruscana Bailey) were prepared to determine the amount of total flavonoids, vitamins A, C, and E, and dietary fiber. Effects of whole grape, pomace, or juice intakes on their antioxidative capacity and DNA damage were investigated in Sprague-Dawley male rats. A total of 120 rats at 13 mo old and weighing 549 +/- 4 g were blocked into 8 groups according to body weight and raised for 3, 5, or 7 mo with diets containing 2% (w/w) dry powder of three different parts of grapes and 0.02% (w/w) CdCl2. The contents of flavonoids, antioxidant vitamins A and E, and dietary fiber in freeze-dried powder were the highest in grape pomace, but the vitamin C contents were similar among the three powders. In all the 16, 18, and 20-mo-old animals, plasma and liver thiobarbituric acid reactive substances levels of grape-ingesting groups were lower than those of the controls and that of the grape pomace group was the lowest among the groups. Cd administration increased plasma and liver thiobarbituric acid reactive substances levels remarkably; however, Cd+grape groups were lower than the Cd-control group. Red blood cell superoxide dismutase activity of 18- and 20-mo-old rats was higher than that of 16-mo-olds, showing an age-related increase; however, red blood cell catalase and glutathione peroxidase activities decreased with age. Grape diets promoted superoxide dismutase, catalase, glutathione peroxidase activities, and the grape pomace increased the activities most significantly among three different parts of the grape. Cd decreased superoxide dismutase, catalase, glutathione peroxidase activities; however Cd+grape groups showed similar activities to the non-Cd control group. Liver superoxide dismutase activity was decreased with age but catalase activity of 18-mo-old rats was higher than those of 16- and 20-mo-old groups, and glutathione peroxidase activities of 16- and 18-mo-old groups were similar but that of 20-mo-old groups decreased markedly. Grape intake increased these three antioxidative enzyme activities while Cd administration decreased catalase and glutathione peroxidase activities except superoxide dismutase activity. The concentration in the kidney of 8-hydroxy-2'-deoxyguanosine in the 18- and 20-mo-old rats was higher than that in the 16-mo-old groups, and grape intake showed a protecting effect on DNA from age-related or Cd-induced oxidative damage. In conclusion, grape intakes, especially grape pomace with the highest content of flavonoids, beta-carotene, tocopherols and dietary fiber among the three parts, showed the prominent antioxidative capacity of inhibiting age-related or Cd-induced increase of lipid peroxidation and DNA damage effectively, promoting liver and red blood cell antioxidant enzyme activities.

Levels of Selenium, Zinc, Copper, and Antioxidant Enzyme Activity in Patients with Leukemia

Essential elements, mainly selenium and zinc, were involved in protection against oxidative stress in cells. Oxidation could lead to the formation of free radicals that have been implicated in the pathogenesis of many diseases, including leukemia. Leukemia is a neoplastic disease that is susceptible to antioxidant enzyme and essential elements alterations. This study was undertaken to examine the levels of essential elements, antioxidant enzymes activities, and their relationships with different types of leukemia. Serum selenium, zinc, and copper concentrations, red blood cell glutathione peroxidase (GPx) activities, plasma Cu-Zn superoxide dismutase (Cu-Zn SOD) activities and lipid peroxidation (LPO) levels were determined in 49 patients with different types of leukemia before initial treatment. Serum selenium and zinc concentrations were lower in leukemia patients than those of controls (p<0.01). Serum copper concentration was higher in leukemia patients than that of controls (p<0.01). The activities GPx and Cu-Zn SOD were significantly increased in leukemia patients, especially with acute leukemia (AL), acute lymphoid leukemia (ALL), and acute nonlymphoid leukemia (ANLL) (p<0.05), whereas no difference was found between those of chronic myelogenous leukemia and the controls. The levels of LPO were normal as controls. Serum selenium concentration was not correlated with GPx, and serum levels of zinc and copper were not related to Cu-Zn SOD. Serum zinc levels had a negative correlation with the absolute peripheral blast cells, whereas serum copper had a positive correlation with the absolute peripheral blast cells. Increased GPx and Cu-Zn SOD activities and normal levels of LPO, which were a protective responses, were an indicator of mild oxidative stress; it might indicate that the essentials elements alterations in leukemia patients were mostly dependent on tumor activity. Changes of their levels demonstrated that there are low selenium, zinc, and high copper status in leukemia patients. The decrease of plasma zinc and increase of the Cu/Zn ratio could be the index that showed an unfavorable prognosis of acute leukemia.

Blood oxidative stress markers in Gaucher disease patients

Background Gaucher disease (GD) is the most common glycosphingolipidosis resulting in accumulation of glucoceramide. The most effective treatment for this disease is enzyme replacement therapy (ERT) which involves recombinant enzyme infusion. Enzymatic deficiency in GD patients may induce a cascade of events culminating in secondary effects such as the production of reactive oxygen species (ROS). We investigated the relationship between ROS and GD by analyzing blood oxidative stress markers in GD patients submitted to ERT at different stages during the treatment. Methods Blood were collected before and just after enzyme infusion. Red blood cell catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) and total glutathione (tGSH), and plasma thiobarbituric acid reactive substances (TBARS) were assayed by spectrophotometry. Homocysteine concentrations and related polymorphisms were also studied. Control individuals matched for sex and age were also analyzed. Results Concentrations of homocysteine and TBARS, and GPx enzyme activity were not different in ERT-treated GD patients. CAT activity was higher while SOD was lower in patients compared to controls. No variations in any of these parameters were found before and just after ERT. Regarding tGSH, a significant increase was observed in GD patients after infusion. Genotypic frequencies studied did not differ from controls or other Brazilian samples. Conclusion ERT-treated GD patients show an improvement in antioxidant capacity, which is further increased just after recombinant enzyme infusion.