RBC GSH Research Articles

The Impact of Bariatric Surgery on Glutathione Synthesis in Individuals with Severe Obesity.

Glycine is deficient in individuals with obesity but improves following bariatric surgery. Glycine deficiency could impair glutathione (GSH) synthesis and worsen oxidative stress. We examined the impact of obesity-associated glycine deficiency and bariatric surgery on GSH synthesis. Twenty-one participants with severe obesity and twenty-one healthy weight controls were recruited. [1,2-13C2] glycine was infused to measure the erythrocyte (RBC) GSH synthesis rate. Participants with obesity underwent bariatric surgery, and 19 were restudied six months post-surgery. Compared to healthy weight controls, individuals with obesity had significantly lower concentrations of RBC GSH (2.43 ± 0.23 vs. 2.63 ± 0.26 mmol/L, p < 0.01). However, there were no differences in GSH fractional synthesis rate [78.0 (51.4-123.7) vs. 76.9 (49.3-110.1) % pool/day, p = 0.58] or absolute synthesis rate [1.85 (1.25-3.32) vs. 1.92 (1.43-3.03) mmol/L RBC/day, p = 0.97]. Despite a post-surgery increase in glycine concentration, no statistically significant changes in RBC GSH concentration or synthesis rates were detected. Further, the significant correlation between plasma glycine and RBC GSH concentration at baseline (r = 0.46, p < 0.01) was also lost following bariatric surgery. GSH concentration was significantly lower in participants with obesity, but bariatric surgery did not significantly increase GSH concentrations or synthesis rates.

Toxic copper level increases erythrocyte glycolytic rate, glutathione production and alters electrolyte balance in male Wistar rats

BackgroundCopper is a micronutrient vital to several cellular energy metabolic processes and drives erythropoiesis. However, it disrupts cellular biological activities and causes oxidative damage when in excess of cellular needs. This study investigated the effects of copper toxicity on erythrocyte energy metabolism in male Wistar rats. MethodsTen Wistar rats (150–170 g) were randomly divided into 2 groups: control (given 0.1 ml distilled water) and copper toxic (given 100 mg/kg copper sulphate). Rats were orally treated for 30 days. Blood, collected retro-orbitally after sodium thiopentone anaesthesia (50 mg/kg i.p.) into fluoride oxalate and EDTA bottles, was subjected to blood lactate assay and extraction of red blood cell respectively. Red blood cell nitric oxide (RBC NO), glutathione (RBC GSH), adenosine triphosphate (RBC ATP) levels, RBC hexokinase, glucose-6-phosphate (RBC G6P), glucose-6-phosphate dehydrogenase (RBC G6PDH), and lactate dehydrogenase (RBC LDH) activity was estimated spectrophotometrically. Values (Mean±SEM, n = 5) were compared by Student’s unpaired T-test at p < 0.05. Results and conclusionCopper toxicity significantly increased RBC hexokinase (23.41 ± 2.80 µM), G6P (0.48 ± 0.03 µM), G6PDH (71.03 ± 4.76nmol/min/ml) activities, ATP (624.70 ± 57.36 µmol/gHb) and GSH (3.08 ± 0.37 µM) level compared to control (15.28 ± 1.37 µM, 0.35 ± 0.02 µM, 330.30 ± 49.58 µmol/gHb, 54.41 ± 3.01nmol/min/ml and 2.05 ± 0.14 µM respectively, p < 0.05). Also, RBC LDH activity (145.00 ± 19.88mU/ml), NO (3.45 ± 0.25 µM) and blood lactate (31.64 ± 0.91 mg/dl) level were lowered significantly compared to control (467.90 ± 94.23mU/ml, 4.48 ± 0.18 µM and 36.12 ± 1.06 mg/dl respectively). This study shows that copper toxicity increases erythrocyte glycolytic rate and glutathione production. This increase could be connected to a compensatory mechanism for cellular hypoxia and increased free radical generation.

Dietary and Lifestyle Factors Modulate the Activity of the Endogenous Antioxidant System in Patients with Age-Related Macular Degeneration: Correlations with Disease Severity.

Age-related macular degeneration (AMD) is a common cause of blindness in the elderly population, but the pathogenesis of this disease remains largely unknown. Since oxidative stress is suggested to play a major role in AMD, we aimed to assess the activity levels of components of the antioxidant system in patients with AMD. We also investigated whether lifestyle and dietary factors modulate the activity of these endogenous antioxidants and clinical parameters of disease severity. We recruited 330 patients with AMD (39 with early, 100 with intermediate and 191 with late form of AMD) and 121 controls in this study. At enrolment, patients’ dietary habits and physical activity were assessed, and each study participant underwent a thorough ophthalmologic examination. The activity of several components of the antioxidant system were measured in red blood cells and platelets using both kinetic and spectrophotometric methods. Patients with AMD consumed much lower levels of fatty fish and eggs than the control group (p = 0.008 and p = 0.04, respectively). In the nAMD group, visual acuity (VA) correlated positively with green vegetable consumption (Rs = +0.24, p = 0.004) and omega-3-rich oil intake (Rs = +0.17, p = 0.03). In the AMD group, the total physical activity MET score correlated positively with VA (Rs = +0.17, p = 0.003) and correlated negatively with the severity of AMD (Rs = −0.14, p = 0.01). A multivariate analysis of patients and controls adjusted for age, sex, and smoking status (pack-years) revealed that AMD was an independent variable associated with a lower RBC catalase (β = −0.37, p < 0.001) and higher PLT catalase (β = +0.25, p < 0.001), RBC GPx (β = +0.26, p < 0.001), PLT GPx (β = +0.16, p = 0.001), RBC R-GSSG (β = +0.13, p = 0.009), PLT R-GSSG (β = +0.12, p = 0.02) and RBC GSH transferase (β = +0.23, p < 0.001) activity. The activities of components of the antioxidant system were associated with disease severity and depended on dietary habits. The observed substantial increase in the activity of many critical endogenous antioxidants in patients with AMD further indicates that the required equilibrium in the antioxidant system is disturbed throughout the course of the disease. Our findings explicitly show that a diet rich in green vegetables, fish and omega-3-rich oils, supplemented by physical exercise, is beneficial for patients with AMD, as it might delay disease progression and help retain better visual function.

Substitution of Dietary Sulfur Amino Acids by ᴅʟ-2-Hydroxy-4-Methylthiobutyric Acid Reduces Fractional Glutathione Synthesis in Weaned Piglets

ABSTRACTBackgroundCys is limiting for reduced glutathione (GSH) synthesis and can be synthesized from Met. We hypothesized that the dietary Met hydroxyl analogue dl-2-hydroxy-4-methylthiobutyric acid (dl-HMTBA) affects Cys and GSH metabolism and oxidative stress defense differently than Met.ObjectiveThe objective was to elucidate whether dl-HMTBA supplementation of a Met-deficient diet affects Cys flux, GSH fractional synthetic rate (FSR), and the basal oxidative stress level relative to Met supplementation in pigs.MethodsTwenty-nine male German Landrace piglets aged 28 d were allocated to 3 dietary groups: a basal diet limiting in Met (69% of Met plus Cys requirement) supplemented with either 0.15% l-Met (LMET; n = 9), 0.15% dl-Met (DLMET; n = 11), or 0.17% dl-HMTBA (DLHMTBA; n = 9) on an equimolar basis. At age 54 d the pigs received a continuous infusion of [1-13C]-Cys to calculate Cys flux and Cys oxidation. After 3 d, GSH FSR was determined by [2,2-2H2]-glycine infusion, and RBC GSH and oxidized GSH concentrations were measured. At age 62 d the animals were killed to determine hepatic mRNA abundances of enzymes involved in GSH metabolism, GSH concentrations, and plasma oxidative stress defense markers.ResultsThe Cys oxidation was 21–39% and Cys flux 5–15% higher in the fed relative to the feed-deprived state (P < 0.001). On average, GSH FSR was 49% lower (P < 0.01), and RBC GSH and total GSH concentrations were 12% and 9% lower, respectively, in DLHMTBA and DLMET relative to LMET pigs (P < 0.05). In the feed-deprived state, Gly flux, the GSH:oxidized glutathione (GSSG) ratio, RBC GSSG concentrations, plasma oxidative stress markers, and the hepatic GSH content did not differ between groups.ConclusionsAlthough GSH FSR was higher in LMET compared with DLMET or DLHMTBA feed-deprived pigs, these differences were not reflected by lower oxidative stress markers and antioxidant defense enzymes in LMET pigs.

ALTERATIONS IN REDOX HOMEOSTASIS IN ELITE ENDURANCE ATHLETES DIAGNOSED WITH UNEXPLAINED UNDER-PERFORMANCE SYNDROME (OVERTRAINING SYNDROME)

BackgroundAlterations in redox homeostasis (ARH) have been implicated in the pathophysiology of Unexplained Under-Performance Syndrome (UUPS). No studies have investigated alterations in ARH in elite athletes with UUPS.ObjectiveTo investigate concentrations...

Pharmacological evaluation of leaves of Jatropha curcas L. for anti-diabetic activity in alloxan induced diabetic rats

Antidiabetic activity of hydroethanolic extract of Jatropha curcas leaves was evaluated using 25 rats equally divided into five groups of five rats each. Group 1 served as healthy control and group 2 as negative control. The study was conducted for the antidiabetic property evaluation after single injection of alloxan drug @ 100 mg/kg b.wt., i.p followed after 48 h by the treatment with the metformin (300 mg/kg) in group 3, hydroethanolic extract of Jatropha curcas leaves (JCE) (200 mg/kg) in group 4 and JCE (400 mg/kg) in group 5. Significant decrease was observed in haematological values of group 2. These values were significantly increased in groups 3 and 5. Total serum protein and albumin values were significantly reduced in group 2 as compared to group 1. But, significant increase was observed in group 3 and 5 in comparison to group 2. A significant increase in serum creatinine, urea, cholesterol, enzymes in group 2 and it significantly reduced in group 3 and group 5. Blood glucose level was significantly increased in group 2 as compared to group 1. Metformin and JCE treated groups had significantly reduced blood glucose level in comparison to group 2. In group 2, LPO level was significantly increased in RBC, liver and kidney but GSH levels were decreased significantly in RBCs, kidney and liver in comparison to group 1. LPO was significantly decreased in kidney and RBCs of group 3 and 5, but there was significant increase in GSH level in liver and RBCs of the group 3 in comparison to group 2.

Critical Difference and Biological Variation in Biomarkers of Oxidative Stress and Nutritional Status in Athletes.

The longitudinal monitoring of oxidative stress (OS) in athletes may enable the identification of fatigued states and underperformance. The application of OS biomarker monitoring programs in sport are hindered by reliability and repeatability of in-the-field testing tools, the turnaround of results, and the understanding of biological variation (BV). Knowledge of BV and critical difference values (CDV) may assist with data interpretation in the individual athlete. Methods: We aimed firstly to assess the repeatability of the clinical point of care redox test, Free Oxygen Radical Test (FORT) and the Free Oxygen Radical Defence (FORD) in trained participants and elite athletes and secondly to calculate the analytical, BV, CDV and index of individuality (II) for FORT, FORD, red blood cell glutathione, lutein, α and γ–tocopherol. Part 1: Fifteen elite athletes were sampled in duplicate for calculation of the repeatability of the FORT and FORD tests. Part 2: Twelve well-trained athletes had venous samples drawn every 2 hours from 0800 to 1800 for calculation of BV, CDV, II for FORT, FORD, RBC GSH, lutein, α-tocopherol and γ–tocopherol. Results: Repeatability of the FORT and FORD assay was 3.9% and 3.7% respectively. Biomarker CDV ranged from 12.8% to 37%, with a circadian effect for FORT, α-tocopherol and γ-tocopherol (p<0.01), with all biomarker indices of individuality < 0.8 arbitrary units. Conclusion: We report that the use of the novel redox test in athletes is practical, and the generation of BV and CDV for biomarkers of OS enhances the interpretation of physiologically meaningful changes in individuals above the use of clinical reference ranges alone.

Effect of Copper on l-Cysteine/l-Cystine Influx in Normal Human Erythrocytes and Erythrocytes of Wilson's Disease.

Wilson's disease is a disease of abnormal copper metabolism in which free serum copper level is raised. The objective of the study was to determine, whether in Wilson disease, l-cysteine/l-cystine influx into RBC was decreased or not and the specific amino acid transporter affected by copper in normal human RBC. For l-cysteine/l-cystine influx, ten untreated cases, ten treated cases and ten age and sex matched healthy controls were recruited. To study the effect of copper on l-cysteine/l-cystine influx in RBC, 15 healthy subjects were selected. RBC GSH and l-cysteine/l-cystine influx were estimated by Beautler's and Yildiz's method respectively. In untreated cases, l-cysteine/l-cystine influx and erythrocyte GSH level were decreased showing that elevated level of free copper in serum or media decreased l-cysteine/l-cystine influx in human RBC. Copper treatment inhibited L amino acid transporter in normal RBC specifically.

Study on effect of Coptidis Rhizoma on red blood cells of normal mice and its antioxidant property

To observe the effect of Coptidis Rhizoma (CR) on hemolysis and antioxidant system of normal mice and its impact on the functions, while evaluating the oxidation reduction property of CR and berberine. In the whole animal experiment, normal mice were orally administered with CR at the dose of 1.2 g x kg(-1) for three days. Their blood were collected to detect the hemoglobin in plasma, the content of serum bilirubin, the number of peripheral blood reticulocytes, the T-AOC in whole blood, measure the contents of glucose-6-phosphate-dehydrogenase (G6PD), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) of RBC membrane, determine the activity of Na(+)-K(+)-ATPase, Ca(2+)-Mg(2+)-ATPase, fluidity, and observe its impact on the liquidity and deformability of RBCs. According to the electrical and biochemical experiment, the voltammetric behaviors of CR and berberine on glassy carbon electrode were evaluated using cyclic voltammetry. In the RBC in vitro experiment, the impact of Coptidis Rhizoma on autoxidation hemolysis rate of RBCs of normal mice was observed. There was no significant effect on hemoglobin, serum bilirubin, and reticulocyte count in normal mice administrated with CR at the dose of 1.2 g x kg(-1), and so is on RBC membrane SOD, G6PD, MDA, GSH and whole blood T-AOC activity. In addition, CR had also no significant effect on Na(+)-K(+)-ATPase, Ca(2+)-Mg(2+)-ATPase activity, and no notable impact on the fluidity and deformability of RBCs. There were two oxidation peaks at -0.27 V and 0.60 V induced by CR and one oxidation peak induced by berberine at 0.56 V, with no reduction peak at fly-back. CR could significantly inhibit oxidative hemolysis in RBCs at the dose of 0.125-2 g x L(-1) in vitro. The normal dose of Coptidis Rhizoma can not cause hemolysis of RBC, and also can not change antioxidant system and functions of RBC, CR and berberine show antioxidant (reducing) properties.

AZT-Induced Oxidative Cardiovascular Toxicity: Attenuation by Mg-Supplementation

Cardiovascular effects of chronic AZT treatment on SD male rats (185 g) fed either a normal Mg diet (0.1% MgO) or a high Mg diet (0.6% MgO) were examined. AZT treatment (1 mg/ml drinking water) for 3 weeks led to a 5.5-fold (0.88 +/- 0.11 nmol/min/10(6) cells, P < 0.05) elevation in neutrophil basal activity of O2(-) production versus controls (0.16 +/- 0.03 nmol/min, assayed ex vivo as SOD-inhibitable cytochrome c reduction). Concomitantly, plasma 8-isoprostane and PGE(2) levels rose 2.1-fold and 3-fold (both P < 0.05), respectively, compared to control; however, RBC GSH decreased 28% (P < 0.02) with GSSG content increased 3-fold, indicative of systemic oxidative stress. High Mg diet substantially attenuated the AZT-induced neutrophil activation by 70% (0.26 +/- 0.05 nmol/min, P < 0.05); reduced plasma 8-isoprostane and PGE(2) to levels comparable to normal; and RBC GSH was restored back to 92% of control. AZT alone caused moderate, but significant vascular inflammatory lesions in the heart (assessed by H&E staining). Immunohistochemical staining revealed significantly higher (about 4-fold) infiltration of CD11b positive cells (WBC surface marker) in the atria and ventricles of AZT-treated rats. However, these inflammatory pathological markers were minimal in samples of rats treated with AZT plus high Mg diet. Moreover, AZT alone significantly (P < 0.02) decreased rat weight gain by 21% at 3 weeks; Mg-supplementation completely prevented (P < 0.05) the weight gain loss due to AZT intake. It is concluded that high dietary Mg may provide beneficial effects against AZT toxicity due to its systemic antioxidative/anti-inflammatory properties.

Glutathione and riboflavin status in patients undergoing home nocturnal hemodialysis versus standard hemodialysis

ObjectivesTo examine whether improved plasma cysteine (tCys) clearance in patients receiving home nocturnal hemodialysis (HNHD) (7 hrs/session, 6 nights/wk), influenced their erythrocyte (RBC) glutathione (GSH) concentration and riboflavin status, compared to patients on standard hemodialysis (SHD) (4 hrs/session, 3 d/wk).MethodsWe measured RBC GSH concentration by liquid chromatography tandem mass spectrometry &amp; riboflavin status by RBC GSH reductase activity coefficient (EGRAC) in 15 HNHD, 15 SHD &amp; 15 healthy controls (HC) participants. Estimated dietary protein intake (PRO), and plasma tCys, homocysteine (tHcy), C‐reactive protein (CRP) and vitamin C were also determined.Median (25th, 75th percentile)ConclusionRBC GSH and riboflavin status may be unaffected by hemodialysis modality in well nourished HD patients. Supported by Kidney Foundation of Canada

Modulation of circulating substance P in Mg‐deficient (MgD) rats by NMDA receptor and neutral endopeptidase inhibitors

Changes in dietary Mg intake influences rat plasma levels of the proinflammatory neuropeptide, substance P (SP), and was associated with altered cardiac tolerance to postischemic stress (Exp Biol Med 228, 2003). In this study, the impact of NMDA receptor inhibition (MK-801, 0.5 mg/kg/day, s.c. pellet) and neutral endopeptidase inhibition (phosphoramidon [PR], 5 mg/kg/day, s.c. pellet) on plasma SP levels were assessed (ELISA) in MgD (Mg = 9% RDA) rats, along with changes in in vivo oxidative stress (RBC GSH loss). During wk 1, MgD alone induced a substantial elevation in SP (0.59 ng/ml/wk) vs Mg-normal rats. PR-treatment of MgD rats during wk 1 led to a further 1.9-fold increase in SP (1.13 ng/ml/wk) and caused a 2-fold greater loss in GSH vs MgD alone. By contrast, continuous MK-801 treatment during 3 wks of MgD caused an overall 49 % reduction in SP vs untreated, but MK-801’s impact was greatest during wk 1 (89 % lower) vs wk 2 (51 %) and wk 3 (30 %). MK-801 treatment of 2 and 3 wk MgD rats led to 38 and 56 % higher GSH levels vs MgD alone, indicating attenuation of oxidative stress. Thus, in addition to a dietary approach (Mg intake), modulating plasma SP levels during MgD by targeted inhibition of neuronal SP release (MK-801) or SP degradation (PR) can also influence the severity of in vivo oxidative stress, and may ultimately impact subsequent cardiac susceptibility to secondary (postischemic) stress. NIH-HL-66226 & HL-65178.

Erythrocyte transmembrane electron transfer in haemodialysis patients

Background and aims Patients with chronic renal failure, especially those treated with haemodialysis, have an increased risk of developing atherosclerotic vascular disease probably as a result of enhanced oxidative stress. The human cell membrane possesses electron transfer systems which protect against extracellular pro-oxidant challenge. We evaluated (1) the erythrocyte velocity of ferricyanide reduction (RBC vfcy) in 25 uraemic patients (aged 25–71 years; 14 males), (2) the changes induced by a single haemodialysis session and (3) biomarkers of oxidative stress. Methods and results Before and after a mid-week dialysis session, we measured RBC vfcy, erythrocyte glutathione (RBC GSH), plasma and red cell membrane malondialdehyde (P and RBC MDA), plasma sulphydryl groups (P SH), plasma vitamin C levels and haemolysis percentage. Pre-dialysis RBC GSH (0.68 ± 0.13 vs 0.80 ± 0.13 mg/mL, p < 0.01), P SH (266 ± 74 vs 406 ± 78 μmol/L, p < 0.01) and plasma vitamin C (7.0 ± 5.1 vs 21.5 ± 8.5 mg/L, p < 0.001) were lower than in 25 age-sex-matched healthy controls; P MDA (1.57 ± 0.52 vs 0.54 ± 0.29 nmol/mL, p < 0.001), RBC MDA (0.42 ± 0.13 vs 0.34 ± 0.16 nmol/mL, p < 0.05) and haemolysis (1.2 ± 0.3 vs 0.7 ± 0.3%, p < 0.001) were increased. Baseline RBC vfcy did not differ from normals (13.1 ± 5.2 vs 12.9 ± 3.2 mmol/mL/h). Following dialysis, RBC vfcy (to 8.9 ± 4.5 mmol/mL/h, p < 0.001) decreased, as well as P MDA, RBC MDA and plasma vitamin C (to 2.5 ± 1.4 mg/L, p < 0.001), whereas P SH groups increased (to 413 ± 99 μmol/L, p < 0.001); haemolysis percentage remained high. RBC vfcy values were correlated to RBC GSH and vitamin C levels. Conclusions Uraemic patients showed signs of oxidative stress. Pre-dialysis RBC vfcy is maintained in the normal range on account of a reduced intracellular content of GSH and in spite of low plasma ascorbate. A single haemodialysis treatment reduced biomarkers of protein and lipid oxidation but markedly impaired transmembrane electron transfer, which could be explained by acute depletion of electron donors.

Credentials of Spirulina diet on stability and flux related properties on the biomineralization process during oxalate mediated renal calcification in rats

High Spirulina diet is a potential risk factor for nephrolithiasis since it has the capacity to increase urinary oxalate and uric acid level, facilitating lithogenesis. Our aim was to identify the effect of Spirulina diet during hyperoxaluric condition in Wistar albino rats. The animals were divided into four groups: control (Gl, n=6); ethylene glycol (EG) induced (G2, n=6); EG+Spirulina (G3, n=6); Spirulina alone (G4, n=6). EG at 0.75% was administered to G2 and G3 through drinking water for 4 weeks and Spirulina 1500 mg/kg feed was administered to G3 and G4. Urinary parameters like oxalate, uric acid, calcium, urea, and creatinine (P<0.001) were found increased after Spirulina diet under hyperoxaluric conditions compared to the same without Spirulina diet. Similarly the BUN, plasma contents of uric acid, urea, creatinine (P<0.001) were found to be raised in G3. The renal and RBC GSH levels, as estimated by HPLC, seemed decreased when compared to G2. The present study shows that free radicals aid in the progression of nephrolithiasis. The crystal deposition was found to be high in the renal cells of G3 than G2 and TEM revealed damage in renal cell of G3 implying that the disease deteriorates by free radical injury. In contrast the Spirulina diet alone (G4) did not induce any features relating to stone forming condition suggesting that free radical release might have been suppressed due to enrichment of dietary antioxidants and vitamins. Thus the present investigation demonstrates that during hyperoxaluric conditions the Spirulina diet must possibly be avoided and can be considered in normal subjects checked for family history of renal stone deposition.

Dietary fat source and cholesterol interactions alter plasma lipids and tissue susceptibility to oxidation in spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats.

Due to the potential for dietary fat source to alter plasma lipids and tissue antioxidant status, we hypothesized that blends of saturated, n-6 and n-3 fats with cholesterol would affect LDL and tissue susceptibility to in vitro oxidation. The effects of dietary fat blends of butter (B), beef tallow (T), soybean oil (SBO) or menhaden oil (MO) and cholesterol on systolic blood pressure (SBP), plasma lipoproteins and tissue susceptibility to glutathione (GSH) depletion and lipid peroxidation (TBARS) were examined in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. SBP in SHRs was higher (p < 0.001) than in WKYs at 13-weeks of age but was not altered by dietary fat or cholesterol. LDL- and HDL-cholesterol were greater (p < 0.001) in WKY than SHR. LDL-cholesterol and (VLDL- + LDL-cholesterol)/HDL-cholesterol ratios were reduced in MO vs. B, T and SBO groups. HDL-cholesterol levels tended to be lower and greater in B and MO groups, respectively vs. T and SBO groups. Initial LDL fluorescence was greater (p < 0.001) in high- vs. low-cholesterol groups. The change in LDL fluorescence was reduced (p < 0.001) in high-cholesterol groups, and MO vs. B, T and SBO rats. MO fed rats had reduced (p < 0.001) RBC, heart and liver GSH depletion and reduced (p < 0.01) tissue TBARS and RBC MDA production. In summary, a moderate level of dietary MO did not increase tissue and LDL in vitro oxidizability in SHR and WKY rats. High dietary cholesterol exhibited a protective effect against in vitro oxidation of LDL and selected tissues.

Biochemical and antioxidant changes in plasma and erythrocytes of pentathlon horses before and after exercise.

Physical exercise in the horse induces a series of normal physiological and biochemical adaptations. Increasing metabolism and oxygen uptake may induce oxidative stress in various organs. The aim of this study was to examine exercise-induced changes in some plasma and RBC biochemical and antioxidant variables in pentathlon horses. Blood samples were taken from 14 horses before, immediately after, and 24 hours after competing in two 1-minute runs of intense exercise over jumps. The peak intensity periods were preceded by a 20-minute warm-up and separated by a 20-minute break. The following plasma biochemical analytes were determined: total protein, uric acid, and lactate concentrations, and lactate dehydrogenase (LDH) and creatine kinase (CK) activities. Total antioxidant status (TAS) and the ferric reducing ability of plasma (FRAP) also were measured. Thiobarbituric acid-reactive substances (TBARS), reduced glutathione (GSH), and total protein concentrations, and glutathione peroxidase (GSHPx) and superoxide dismutase (SOD) activities were determined in RBC hemolysates. Significantly increased concentrations of total protein, lactate, and FRAP, and increased activities of CK and LDH were observed immediately postexercise compared with pre-exercise samples (P<0.05). All results returned to approximately initial values after 24 hours of rest. RBC GSH and TBARS concentrations did not change immediately after exercise, but decreased after 24 hours of rest (P<0.05). Plasma uric acid and FRAP values were positively correlated in a linear model (r = 0.78). In summary, the type of exercise applied in this study, which can be considered quite usual for pentathlon horses, caused detectable biochemical and lipid peroxidative changes in plasma and RBCs. FRAP and TAS values changed in opposite directions, indicating that when antioxidant capacity is assessed using different methods, highly different results may be obtained.

Lipid peroxidation, osmotic fragility and antioxidant status in children with acute post-streptococcal glomerulonephritis

Plasma and erythrocyte samples from acute post-streptococcal glomerulonephritis (APSGN) children and control children were enrolled in this study. Lipid peroxidation (LPO), measured in terms of thiobarbituric acid-reactive substances (TBARS) was found to be significantly increased in plasma and RBCs of APSGN children ( P<0.05) than in control children. Osmotic fragility of erythrocytes was examined. RBCs of APSGN patients were found to be osmotically more sensitive towards hypotonic saline (50% hemolysis at 7 g/l saline) when compared to control RBCs (50% hemolysis at 4 g/l saline). The activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were significantly lowered ( P<0.05) in APSGN RBCs when compared to control RBCs. Plasma ascorbic acid, reduced glutathione (GSH), RBC ascorbic acid, GSH and RBC total sulphydryl content (TSH) were significantly depleted in APSGN children relative to controls. The susceptibility of RBCs of APSGN children to lipid peroxidation was confirmed in this study.

Transmembrane electron transfer in diabetic nephropathy.

Erythrocytes (red blood cells [RBCs]) reduce extracellular ferricyanide by transmembrane transfer of reducing equivalents involving ascorbate recycling. Because ascorbate regeneration is glutathione (GSH) dependent and cells may be depleted of GSH in diabetes, we measured RBC GSH, plasma sulfhydryl (SH) groups, and RBC-mediated ferricyanide reduction in 30 type 1 diabetic patients (age 34 +/- 10 years, disease duration 20 +/- 8 years; no complications, n = 10; retinopathy, n = 10; nephropathy, n = 10), their 36 siblings (age 39 +/- 13 years), and matched healthy volunteers. Fasting plasma glucose was 15 +/- 7 mmol/l (vs. 5 +/- 1 in control subjects, P < 0.001), HbA1c 8.4 +/- 1.5% (vs. 5.4 +/- 0.3, P < 0.001), GSH 0.76 +/- 0.12 mg/ml packed RBCs (vs. 0.88 +/- 0.18, P < 0.01), SH groups 401 +/- 72 micromol/l (vs. 444 +/- 56, P < 0.05), and ferrocyanide generation 15 +/- 5 micromol/ml RBC per h (vs. 13 +/- 5, NS). In comparison with 10 normoalbuminuric diabetic subjects with retinopathy, 10 patients with diabetic nephropathy had similar fasting plasma glucose, HbA1c, and SH groups; lower RBC GSH (0.73 +/- 0.08 vs. 0.85 +/- 0.11, P < 0.05); and higher ferrocyanide generation (18 +/- 4 vs. 14 +/- 5, P < 0.05). The 10 patients without complications differed from the 10 healthy volunteers in glycemic control and RBC GSH. RBC electron transfer correlated with plasma lactate (r = 0.8, P = 0.01) only in the uncomplicated group. No difference was detected between siblings and healthy control subjects or between siblings of subjects in the nephropathy and retinopathy groups. Among diabetic patients, the rate of ferrocyanide generation was associated with urinary albumin excretion, plasma creatinine, and SH groups (multiple r = 0.6, P < 0.01). Transmembrane electron transfer is selectively increased in diabetic nephropathy, where RBC GSH is also depleted. The abnormality is peculiar to the nephropathy group and not contributed by familial or hereditary components because the electron flow was normal in siblings. The close relationship between cytosolic NADH and RBC electron transfer observed in diabetic patients without complications seems to be lost in the microangiopathic patients. Whereas patients with retinopathy alone still had normal activity of the RBC-reducing system, patients with nephropathy showed significantly increased activity, unrelated to metabolic parameters or plasma lactate concentration and correlated with renal function parameters and plasma thiols.

Arsenic-induced oxidative stress and its reversibility following combined administration of N-acetylcysteine and meso 2,3-dimercaptosuccinic acid in rats.

1. The present study examined whether arsenic induces oxidative stress in liver, brain and erythrocytes (RBC) based on the investigation of certain selected parameters. It also explored the possibility that combined administration of N-acetylcysteine (NAC) and meso 2,3-dimercaptosuccinic acid (DMSA) was capable of achieving better reversibility in the parameters indicative of arsenic-induced oxidative stress than individual treatment with either of these drugs. 2. Male rats were exposed to 100 p.p.m. sodium arsenite in their drinking water for 12 weeks (equivalent to 12 mg/kg As). The arsenic was then removed and rats were given NAC (1 mmol/kg per day), DMSA (1 mmol/kg per day) or a combination of the two, orally, once daily for 5 days. Animals not given arsenic and those given arsenic but not NAC or DMSA served as negative and positive controls, respectively. 3. Twelve weeks of arsenic exposure was found to deplete glutathione (GSH) levels, increase oxidized glutathione (GSSG) and promote malondialdehyde (MDA) production in both liver and brain samples. In addition to a significant reduction in RBC delta-aminolevulinic acid dehydratase (ALAD) activity and GSH levels, a marked elevation in MDA production may also contribute to arsenic-induced oxidative stress. 4. Treatment with either NAC or DMSA alone partially reversed arsenic-induced alterations in hepatic GSH and MDA, while only brain MDA levels responded favourably to these drugs. Only DMSA appeared to restore blood ALAD, while RBC MDA levels responded favourably to both drugs. Treatment with DMSA also produced an effective depletion of blood and hepatic arsenic concentrations. In the liver, most of these parameters were more effectively reversed by combined treatment with NAC and DMSA compared with the effects of either drug alone. 5. These results provide in vivo evidence of arsenic-induced oxidative stress in liver, brain and RBC and indicate that these effects can be mitigated by pharmacological intervention that encompasses combined treatment with NAC and DMSA.

659 HERIDITARY ELLIPTOCYTOSIS, RED CELL FRAGMENTATION, AND DECREASED GLUTATHIONE (GSH)

Marked poikilocytosis accompanied by membrane fragmentation and microspherocyte formation have been described in occasional cases of hereditary elliptocytosis. We have studied a healthy 10 year old black male with a compensated hemolytic anemia, elliptocytosis and severe red cell fragmentation. Several parameters known to affect RBC membrane stability were found to be normal: pyruvate kinase activity, RBC ATP content, unstable hemoglobin evaluation, direct and indirect Coomb's tests, membrane thermal sensitivity, RBC calcium and calcium permeability, RBC cholesterol and phospholipid content, and the distribution of membrane phosphatides including phosphatidyl ethanolamine. The only abnormality found was a RBC GSH content approximately 50% of normal (below that seen in most G-6-PD deficiencies). Furthermore, in centrifugally-separated cells, GSH content decreased progressively with increasing cell density. Unlike G-6-PD deficiency the low GSH content was not accompanied by abnormal oxidant sensitivity; GSH was not diminished by incubation with ascorbate-aminotriazole and no methemoglobin or sulfhemoglobin was formed. Enzymes involved in GSH metabolism (GSH reductase, G-6-PD, GSH peroxidase) were slightly elevated. Incubation of RBC with H3-glutamate, with subsequent molecular weight separation of the GSH inermediates, suggests an intact GSH synthetic pathway but diminished H3-glutamate content. The low RBC GSH may be related to the RBC morphologic features and hemolysis.