Study of the activity of glutathione-peroxidase,glutathione-transferase,and glutathione-reductase in renal transplants

The aim of this work was to study the temporare variation of oxidative stress in the plasma and erythrocytes (CR) of renal transplant patients We determined total glutathione (GST), as well as oxidized (GSSG) and reduced (GSH) fractions and the activity of glutathione peroxidase (G-px), glutathione reductase (G-red) and glutathione transferase (GSt). Determinations were performed 48 hours before transplant as well as 1 and 2 weeks after the renal transplant. The results showed a high "oxidative stress" rate, resulting from the equilibrium between the production of free radicals and the activity of antioxidants, the former being higher proportionally. Immediately after the transplant, there was an increase in oxidative stress, which resulted in an increased G-red, a marked decrease in plasma and in erythrocyte G-px (CR9 and an abrupt drop both in GST levels in plasma and in GSG (as well as in the [GSH]/[GSSG] relationship). Thereafter there was a significant improvement in the activity of antioxidant enzymes, but without normalization; the total glutathione levels and the activity of various enzymes approached the average values of the control group.     

GLUTATHIONE DETERMINATION AND A STUDY OF THE ACTIVITY OF GLUTATHIONE-PEROXIDASE,GLUTATHIONE-TRANSFERASE,AND GLUTATHIONE-REDUCTASE IN RENAL TRANSPLANTS

The aim of this work is to study the temporary variation of oxidative stress in renal transplants, both in plasma and in erythrocytes (CR). In order to do so, we determined total glutathione (GST) levels, both oxidized (GSSG) and reduced (GSH), and the activity of enzymes, glutathione peroxidase (G-px), glutathione reductase (G-red) and glutathione transferase (GSt), in renal transplant patients. Determinations were made 48 h before the transplant 1 week and 2 weeks after the renal transplant. The results obtained confirm a high “oxidative stress” rate, resulting from the equilibrium between the production of free radicals and the activity of antioxidants, the former being higher proportionally. Immediately after the transplant there is an increase of oxidative stress, which results in an increase of G-red, a marked decrease of G-px in plasma and in erythrocytes (CR) and an abrupt drop both in GST levels in plasma and in GSG (as well as in the [GSH]/[GSSG] relationship). As times goes on, after the transplant, there is a significant improvement in the activity of antioxidant enzymes, but there is no normalization, which is easily seen in the fact that total glutathione levels and the activity of the various enzymes approach the average values of the control group.     

Oxidative stress markers in pre-uremic patients.

AIM: The present study was designed to investigate a complex of oxidative stress (OS) markers in patients with chronic renal failure (CRF) and to study the relationship between different OS markers and degree of renal failure. The following indices of OS were measured in plasma: oxidized glutathione (GSSG), reduced glutathione (GSH), total glutathione (TGSH), glutathione redox ratio (GSSG/GSH) and resistance of lipoprotein fraction to oxidation (lag phase of LPF). Baseline diene conjugation level of lipoprotein fraction (BDC-LPF), total antioxidative activity (TAA), diene conjugates (DC), lipid hydroperoxides (LOOH) and thiobarbituric acid-reactive substances (TBARS) were measured in serum. All markers in plasma and serum were measured both in patients with CRF and in healthy controls. SUBJECTS AND METHODS: Blood samples were obtained from 38 patients with CRF and from 61 healthy controls. Routine biochemical analyses were performed by using commercially available kits. RESULTS: Levels of DC, BDC-LPF, LOOH, GSSG and GSSG/GSH ratio were significantly increased and lag phase of LPF was significantly shortened in patients with CRF compared with healthy controls. Serum creatinine and urea levels correlated significantly with GSSG level and GSSG/GSH in patients with CRF. A significant inverse correlation was found between glutathione redox ratio and lag phase of LPF and between GSSG level and BDC-LPF. CONCLUSIONS: The findings suggest that renal patients are in a state of oxidative stress compared with healthy controls. The most informative indices to evaluate the degree of OS in CRF were: GSSG level, GSSG/GSH status, lag phase of LPF and BDC-LPF.     

Plasma Homocysteine and Glutathione Are Independently Associated With Estimated Glomerular Filtration Rates in Patients With Renal Transplants

BackgroundElevated levels of plasma homocysteine could, through homocysteine oxidation, induce the overproduction of reactive oxygen species, leading to a reduction in glutathione-related antioxidants, and may impair graft functions in patients with renal transplants. The purpose of this study was to determine whether plasma homocysteine, glutathione, or its related antioxidants were related to graft functions in patients with renal transplants.Patients and MethodsWe recruited 66 patients (mean age 48.4 years) with renal transplants (mean transplant duration 8.3 years). Patients were divided into 2 groups, based on their estimated glomerular filtration rate (eGFR): the moderate graft function group (eGFR ≥ 60 mL/min/1.73 m², n = 37) and low graft function group (eGFR < 60 mL/min/1.73 m², n = 29). We then determined their fasting levels of the following: malondialdehyde (MDA), homocysteine, cysteine, pyridoxal 5′-phosphate (PLP), glutathione (GSH), oxidized glutathione (GSSG), GSH/GSH ratio, glutathione peroxidase (GSH-Px) activity.ResultsWe found in the low graft function group significantly higher levels of plasma homocysteine, cysteine, GSH, and GSH/GSSG ratios. But an intergroup difference was not found regarding levels of MDA, PLP, GSSG, and GSH-Px activity. After adjusting for potential confounders, the increased plasma homocysteine and GSH levels were independently associated with lower eGFR. No interaction existed between homocysteine and GSH levels in association with eGFR.ConclusionIncreased plasma homocysteine and GSH levels appeared to be independent indicators of decreased graft functions in patients with renal transplants.     

Oxidative stress, hepatocellular integrity, and hepatic function after initial reperfusion in human hepatic transplantation

BACKGROUND: The mechanisms underlying liver graft dysfunction are not completely defined, although much of the injury derives from oxidative stress in organ reperfusion. The antioxidant glutathione in its reduced form (GSH) is an important agent to detoxify oxygen species after reperfusion. However, this effect might be limited by low concentrations at the end of cold storage. The objective of this study was to evaluate GSH and glutathione oxidized (GSSG) hepatic levels pre- and postreperfusion and correlate with hepatocellular injury and liver function in the 5 subsequent days after transplantation. METHODS: Liver biopsies were taken immediately before implant and 2 hours after venous reperfusion in 34 grafts, determining GSH, GSSG levels, and GSSG/GSH ratio. Aminotransferases (ALT, AST) and PT were measured for 5 days. RESULTS: There was a strong decrease in GSH concentration (P <.0001), increase of GSSG levels (P <.01), and increase of the GSSG/GSH ratio (P <.0001). No correlations were found between GSH, GSSG, or GSH/GSSH levels and AST, ALT, and PT. CONCLUSION: Glutathione levels showed significant changes after 2 hours of reperfusion, due to intense oxidative stress. Therapies to replenish GSH should be considered as a protective measure to avoid liver graft dysfunction after transplantation.     

Altered antioxidant capacity in human renal cell carcinoma: role of glutathione associated enzymes

PURPOSE: We aimed to discern the role of glutathione (GSH) associated enzymes in maintaining high GSH levels in renal cell carcinoma (RCC) of the clear cell type and analyze RCC enzyme antioxidant capacity. Since changes in cellular redox balance in RCC might also be related to alterations of glutathione S-transferase (GST) phenotype, GST class alpha and pi expression was also explored. METHODS AND MATERIALS: Human kidney specimens of tumor and distant nontumor regions were obtained from 15 patients with RCC at the time of surgery. The activities of GSH-replenishing enzymes, gamma-glutamylcysteine synthetase (gamma-GCS), gamma-glutamyl transferase (gamma-GT), and glutathione reductase (GR), as well as the activities of antioxidant enzymes glutathione peroxidase (GPX) and catalase (CAT) were determined spectrophotometrically. GST alpha and pi class expression was determined by immunoblot. RESULTS: In the course of renal cancerization, significant changes appear in the activities of GSH-replenishing and antioxidant enzymes. The activity of the key enzyme of GSH synthesis, gamma-GCS, is up-regulated (P < 0.001), while the activities of gamma-GT and GR are down-regulated in renal tumors compared to nontumor tissue (P < 0.001 and P < 0.05, respectively). Activities of GPX and CAT were also down-regulated (P < 0.001 and P < 0.05, respectively) in RCC. Changes in enzyme antioxidant capacity in RCC were associated with decreased GST class alpha (P < 0.001) and unchanged GST pi expression at the protein level. CONCLUSIONS: Changes in redox status in RCC as a consequence of decreased enzyme antioxidant capacity, together with altered GST alpha expression, may be important factors in development and tumor growth. The up-regulation of gamma-GCS and high levels of GSH in RCC may be an attempt to limit injury caused by oxidative stress.     

Anemia and chronic renal failure: the possible role of the oxidative state of glutathione

The authors have investigated the oxidative state of glutathione in red blood cells (RBC) and plasma from patients affected by chronic renal failure (CRF) and from age-matched healthy subjects. RBC-reduced glutathione (GSH) levels were significantly lower in CRF patients than in healthy subjects. Oxidized glutathione (GSSG) levels in plasma from CRF patients were higher than in plasma from controls. GSSG levels in RBC were similar in both groups. No differences were noted in GSH plasma levels between patients and controls. The GSSG/GSH ratios in RBC were similar in the two groups; on the contrary, the GSSG/GSH ratio in plasma was significantly higher in CRF patients. High levels of GSSG in plasma could exert two important effects on RBC: (1) inhibition of glucose-6-phosphate dehydrogenase activity, with a consequent alteration of the glutathione system; (2) GSSG easily reacts with hemoglobin to produce hemoglobin-glutathione mixed disulfides, with a consequent protein aggregation and precipitation. In vitro experiments have shown that RBC from CRF patients easily lyse when incubated with their same plasma, but not when incubated in saline buffer. Our results seem to demonstrate that plasma from CRF patients contains various oxidants which could affect the integrity of the glutathione system in RBC. This alteration could play a role in the pathogenesis of anemia in uremic patients.     

Heterotopic rat heart transplantation: severe loss of glutathione in 8-hour ischemic hearts.

BACKGROUND: Tissue damage caused by reactive oxygen species (ROS) formed during ischemia/reperfusion seems to be an important risk factor in the failure of transplanted hearts. Although endogenous anti-oxidants protect the myocardium against free radical attack under physiologic conditions, their capacity may become limited during severe oxidative stress. Thus, we investigated the effect of 8-hour cold ischemia on the myocardial anti-oxidative defense system in a heterotopic rat heart transplantation model. METHODS: Lewis rat hearts were subjected to 30 or 480 minutes of 4 degrees C cold ischemia in Bretschneider cardioplegic solution with or without transplantation and reperfusion (30 or 240 minutes) into F344 recipients. Activity levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase (GST), and concentrations of glutathione (GSH), glutathione disulfide (GSSG) and lipid hydroperoxides (LOOH) were analyzed in heart homogenates. For histology, cross-sections of the ventricles were stained with hematoxylin-eosin. RESULTS: Except for GST, enzyme activities and GSSG concentration increased and the glutathione redox ratio (GSH/GSH + 2GSSG) significantly decreased in 480-minute ischemic hearts compared with those with 30-minute ischemia. Reperfusion dramatically decreased both GSH and GSSG and increased LOOH formation but without severe histopathologic findings in the transplants. Applying a tree-structured classifier technique, GSH and LOOH were identified as significant features indicative of transplantation-induced oxidative stress. CONCLUSIONS: In the present study severe loss of glutathione and formation of LOOH indicated transplantation-induced oxidative stress in the rat heart; therefore, alterations of these parameters may hint at relevant deficits in the myocardial anti-oxidative defense and may also predict subsequent tissue damage.     

Oxidative stress and endothelial function in chronic renal failure.

This study aimed to investigate the relationship between oxidative stress and endothelium-dependent vasodilation in patients with chronic renal failure (CRF). Thirty-seven patients with CRF underwent evaluation of endothelium-dependent vasodilation and endothelium-independent vasodilation by means of forearm blood flow measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (evaluating endothelium-dependent vasodilation) and sodium nitroprusside (evaluating endothelium-independent vasodilation). Lag phase of lipoprotein fraction to oxidation, total antioxidative activity, diene conjugates, thiobarbituric acid reactive substances, lipid hydroperoxide, reduced glutathione (GSH), oxidized GSH (GSSG), and the GSH redox ratio (GSSG/GSH) were all measured as markers of oxidative stress. Two groups of healthy subjects (61 and 37 subjects, respectively) were used as controls. In one group, oxidative stress markers were measured, whereas endothelium-dependent vasodilation and endothelium-independent vasodilation were assessed in the other group. Compared with controls, the patients with renal insufficiency had an impaired endothelium-dependent vasodilation, a shorter lag phase of lipoprotein fraction, and higher levels of diene conjugates, lipid hydroperoxide, and GSSG levels. The GSSG/GSH ratio was lower in patients with CRF. Endothelium-dependent vasodilation was positively correlated with total antioxidative activity (r = 0.41, P = 0.016), GSH (r = 0.44, P < 0.0098), and lag phase of LDL (r = 0.35, P = 0.036) and negatively correlated with GSSG (r = -0.40, P < 0.018), GSSG/GSH (r = -0.47, P = 0.0057), and diene conjugates (r = -0.53 P < 0.0015) in patients with CRF. These results show that an impaired endothelium vasodilation function and oxidative stress are related to each other in patients with CRF.     

The effect of prostate cancer and antiandrogenic therapy on lipid peroxidation and antioxidant systems

In living organism, excessive free radicals or oxidative damage which occur as a result of deficient antioxidant defensive mechanisms by the effect of endogenous and exogenous factors, influences especially developmental steps of chemically induced cancers. In our study, plasma malondialdehyde level (MDA) as an indicator of lipid peroxidation, erythrocyte glutathione (GSH) level as an indicator of antioxidant state, glutathione reductase (GSH-Red), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST) as an antioxidant enzymes and plasma vitamin E level were detected in patients with prostate cancer (21 males; age, 69.4 +/- 4.8 years) before and after three months of antiandrogenic therapy with goserelin acetate as luteinizing hormone releasing hormone (LHRH) analogue. Healthy people evaluated as a control group (20 males; age, 63.7 +/- 3.9). Erythrocyte GSH levels, the activities of GSH-Red and GSH-Px and plasma vitamin E levels were found significantly low in patients with prostate cancer when compared with the healthy subjects (p < 0.01, p < 0.05, p < or = 0.001 and p < or = 0.001 respectively). Plasma MDA level and erythrocyte GST activity of patient group were significantly higher than the levels of control group (p < or = 0.001 and p < or = 0.001 respectively). After antiandrogenic therapy erythrocyte GSH level, GSH-Red, GSH-Px activity and plasma vitamin E level were found unchanged. Significant decrease in plasma MDA level and significant increase in erythrocyte GST activity were detected in patient group (p < 0.05 and p < or = 0.01 respectively). The study has revealed the shift in the oxidant-antioxidant balance towards oxidative state in patients with metastatic prostate cancer. Our results showed that antiandrogenic therapy increased in GST activity, decreased in lipid peroxidation.     

Oxidative stress and metallothionein expression in the liver of rats with severe thermal injury

The aim of this work was to study oxidative stress and the compensating mechanisms implicated in severe thermal injury using the burned rat model. Results showed that after thermal injury glutathione (GSH) level was decreased, oxidized glutathione (GSSG) and the ratio of GSSG/GSH increased both at 24 and 48 h in the liver. The activities of GSH-reductase (GSH-Rx) in the liver and GSH-peroxidase (GSH-Px) both in the liver and erythrocytes increased at 24 h and then decreased at 48 h. The level of alpha-tocopherol in plasma was reduced at 24 h. Lipid peroxide levels increased both at 24 and 48 h in the liver. The serum zinc level decreased, reaching a minimum at 12h, whereas liver zinc level was elevated and reached the maximum at 12 h. After severe thermal injury enhancement of metallothionein (MT) expression has been discovered for the first time. MT content in the liver increased both at 24 and 48 h. Expression of MT-I mRNA was activated at 3 h and reached the top at 24 h postburn. The conclusion is that severe thermal injury gives rise to oxidative stress and dramatic enhancement of MT expression could be one of the important compensative mechanisms of natural defense system postburn.     

Early phase of reperfusion of human kidney allograft does not affect an erythrocyte anti-oxidative system

Background: Generation of reactive oxygen specimens is the basic mechanism leading to ischaemia/reperfusion injury of the kidney graft. Oxygen burst is a trigger for sophisticated biochemical changes leading to generation of oxygenated lipids and changes in microcirculation, which recruit recipient’s neutrophils and contribute to delayed graft function. It has been shown that the free radicals generation correlates with the activity of anti‐oxidative system. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione (GSH) are involved in protection against free radicals. Aim: To examine the activity of erythrocyte anti‐oxidative system during reperfusion of the transplanted kidney allograft. Methods: The study included 40 renal transplant recipients. Blood was taken from the iliac vein before transplantation and from the graft’s renal vein immediately, as well as 2 and 4 min after total reperfusion. The authors assessed the process of reperfusion using ThermaCAM SC500 termovision camera. Spectrophotometric methods were used to measure superoxide dismutase, glutathione peroxidase and catalase activity as well as glutathione concentrations in erythrocytes. Results: There were no statistically significant differences in the activities of superoxide dismutase, catalase and glutathione peroxidase as well as glutathione concentrations during the first 4 min after total graft reperfusion. Nevertheless, there was a positive correlation between the activity of superoxide dismutase and glutathione peroxidase. Conclusion: The results suggest that the erythrocyte anti‐oxidative system is stable during the early phase after reperfusion. An association between some anti‐oxidative enzymes was noted.     

Starvation-related alterations in free radical tissue defense mechanisms in rats

Alterations in endogenous free radical-scavenging defense mechanisms of rat tissues after body weight loss (induced by starvation for 72 h) associated with hypoinsulinemia were investigated. The activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and glutathione (GSSG) reductase as well as levels of reduced glutathione (GSH) were examined in several tissues and in erythrocytes. A complex pattern of changes was observed. CAT activities were increased in the heart and pancreas and decreased in the liver. SOD levels were decreased in the heart and increased in the kidney and pancreas. GSH-PX activities were increased only in the kidney, and levels of GSH were decreased only in the liver of starved animals. Erythrocytes from starved animals showed no alterations in the levels of major free radical-scavenging enzymes. However, GSSG reductase levels were lower in erythrocytes from starved animals, and this was associated with an increased susceptibility to H2O2-induced GSH depletion. Paradoxically, H2O2-induced malondialdehyde (MDA) production in erythrocytes from starved animals was lower than that in control erythrocytes. Our results suggest that, in studies of experimental diabetes, attention must be given to the influence of body weight loss per se on the biochemical alterations associated with this disease.     

Markers of oxidative stress after renal transplantation

Abstract An increased degree of oxidative stress (OS) in chronic renal failure (CRF) and a possible role of free radicals in CRF have already been described. However, data on OS after renal transplantation are scarce. The aim of the present study was to estimate the degree of OS in renal transplant patients. The study included four groups: 1) 15 haemodialysis patients (HD group), 2) 11 renal transplant patients with stable function (SF group), 3) 12 renal transplant patients with chronic biopsy-proven rejection (CR group), and 4) 10 healthy controls (C group). Markers of OS (malondialdehyde and thiol group levels) and antioxidant activity (glutathione peroxidase and Cu, Zn-su-peroxide dismutase) were determined in plasma and in red blood cells of all examined individuals. After successful renal transplantation a significant improvement, but not normalization, of antioxidant enzyme activities accompanied by significantly reduced lipid peroxidation were found. In the CR group the degree of OS was increased, and our results suggest that OS may be a relevant pathophysiological factor for CR development.     

Effects of amlodipine and valsartan on oxidative stress and plasma methylarginines in end-stage renal disease patients on hemodialysis

Patients with end-stage renal disease (ESRD) receiving hemodialysis (HD) treatment have a markedly shortened life expectancy in large part owing to cardiovascular disease (CVD), not explained by established risk factors. We tested the hypothesis that therapy with valsartan, an angiotensin receptor blocker and amlodipine, an antioxidant calcium channel blocker will reduce oxidative stress and the plasma levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase. We confirmed that compared with age- and gender-matched healthy controls, ESRD patients have excessive oxidative stress and arginine methylation as indexed by elevated plasma levels of oxidation products of lipids (13-hydroxyoctadecadienoic acid (13-HODE)), thiols (oxidized:reduced glutathione, oxidized glutathione (GSSG):GSH), proteins, and nucleic acids, and the methylation products ADMA and symmetric dimethylarginine (SDMA). We undertook a double blind, crossover study of equi-antihypertensive treatment with amlodipine and valsartan for 6 weeks each to test our hypothesis. Both treatments significantly reduced GSSG:GSH, 8-hydroxy 2-deoxyguanosine, ADMA, and SDMA levels and amlodipine reduced 13-HODE. We conclude that hypertensive patients with ESRD receiving HD have evidence of extensive oxidation of lipids, thiols, proteins, and nucleic acids and methylation of arginine that could contribute to CVD. Many of these changes can be reduced by short-term treatment with amlodipine and valsartan.     

Renal tubular cell damage and oxidative stress in renal stone patients and the effect of potassium citrate treatment

Our objective was to evaluate the oxidative stress and renal tubular cell damage in patients who have renal stones compared to normal subjects. The patients were re-evaluated after 1-months supplementation with potassium citrate. We recruited 30 patients (11 males and 19 females) diagnosed with kidney stones and scheduled for surgical stone removal the following month, and 30 healthy non-stone formers (14 males and 16 females). Two 24-h urine samples and one heparinized blood sample were collected from each subject. Plasma was separated from the erythrocytes and assayed for creatinine, potassium, sodium, calcium, magnesium, phosphate, malondialdehyde (MDA, a lipid peroxidation product) (P-MDA), protein thiol as an indicator of protein oxidation, and vitamin E. Erythrocytes were analysed for MDA (E-MDA), reduced glutathione (GSH) and cellular glutathione peroxidase (cGPx) activity. The urine was analyzed for pH, creatinine, potassium, sodium, calcium, magnesium, phosphate, oxalate, citrate, MDA (U-MDA), total protein (U-protein) and N-acetyl--glucosaminidase (NAG) activity. For the stone patients, urine and blood samples were re-evaluated after supplementation with potassium citrate (60 mEq/day) for 1 month. Renal stone patients had higher plasma creatinine and lower plasma potassium, urinary pH, potassium, magnesium, phosphate and citrate than the controls. The patients had higher P-MDA, E-MDA, U-MDA, U-protein and NAG activity, but lower GSH, cGPx activity, protein thiol and vitamin E, when compared with controls. After potassium citrate supplementation, P-MDA and E-MDA decreased while plasma vitamin E, urinary NAG activity and citrate increased. Renal stone disease is associated with high oxidative stress and damage to renal tubular cells. These abnormalities are coincident with an increase in blood lipid peroxidation products and a decrease in antioxidant status. Although supplementation with potassium citrate improved urinary citrate levels and oxidative stress, it neither reduced urinary lipid peroxidation products nor remedied the damage to renal tubular cells, probably due to the existence of kidney stones.     

The effect of prostate cancer and antianrogenic therapy on lipid peroxidation and antioxidant systems

In living organism, excessive free radicals oroxidative damage which occur as a result of deficient antioxidant defensive mechanisms by the effect of endogenous and exogenous factors, influences especially developmental steps of chemically induced cancers [1, 2]. In our study, plasma malondialdehyde level (MDA) as an indicator of lipid peroxidation, erythrocyte glutathione (GSH) level as an indicator of antioxidant state, glutathione reductase (GSH-Red), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST) as an antioxidant enzymes and plasma vitamin E level were detected in patients with prostate cancer (21 males; age, 69.4 ± 4.8 years) before and after three months of antiandrogenic therapy with goserelin acetate as luteinizing hormone releasing hormone (LHRH) analogue. Healthy people evaluated as a control group (20 males; age, 63.7 ± 3.9). Erythrocyte GSH levels, the activities of GSH-Red and GSH-Px and plasma vitamin E levels were found significantly low in patients with prostate cancer when compared with the healthy subjects (p < 0.01, p < 0.05, p ≤ 0.001 and p ≤ 0.001 respectively). Plasma MDA level and erythrocyte GST activity of patient group were significantly higher than the levels of control group (p ≤ 0.001 and p ≤ 0.001 respectively). After antiandrogenic therapy erythrocyte GSH level, GSH-Red, GSH-Px activity and plasma vitamin E level were found unchanged. Significant decrease in plasma MDA level and significant increase in erythrocyte GST activity were detected in patient group (p < 0.05 and p ≤ 0.01 respectively). The study has revealed the shift in the oxidant-antioxidant balance towards oxidative state in patients with metastatic prostate cancer. Our results showed that antiandrogenic therapy increased in GST activity, decreased in lipid peroxidation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Total antioxidant and oxidant status of plasma and renal tissue of cisplatin-induced nephrotoxic rats: protection by floral extracts of Calendula officinalis Linn.

The present study was aimed to determine the total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) of plasma and renal tissue in cisplatin (cDDP) induced nephrotoxic rats and its protection by treatments with floral extracts of Calendula officinalis Linn. Treatment with cDDP elevated (p?p?C. officinalis along with cDDP restored (p?>?0.05) CR, albumin, TOS, GSH and activities of antioxidant enzymes in blood and renal tissue. Ethanolic extract treatments reduced (p?C. officinalis protect cDDP induced nephrotoxicity by restoring antioxidant system of the renal tissue.     

Lipid peroxidation and antioxidant enzymes in children on maintenance dialysis

End-stage renal disease (ESRD) is associated with numerous complications, which may partly result from excessive amounts of reactive oxygen species and/or decreased antioxidant activity. The aim of the study was to evaluate lipid peroxidation (LP) in plasma and erythrocytes, erythrocyte antioxidant enzyme activity (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GSH-Px), and concentrations of Cu and Zn as cofactors of SOD and Se as a cofactor of GSH-Px in erythrocytes, plasma and in dialysis fluid in children with ESRD. In particular, we analyzed whether the modality of dialysis could modify oxidative stress parameters in children. To determine the influence of hemodialysis (HD) on oxidative stress, the measurements were also performed on HD children 20 min after the beginning of the dialysis session. Thirty-one patients participated in the study: group I with 10 children on continuous ambulatory peritoneal dialysis (CAPD), and group II with 21 on HD. The erythrocyte malondialdehyde concentrations (E-MDA), plasma MDA (P-MDA) and plasma organic hydroperoxide (OHP) in children from both groups were higher than in controls. E-MDA and P-MDA in HD before the session was lower compared to the values after 20 min of HD session (time T²⁰). The activity of SOD, GSH-Px, CAT, concentrations of erythrocyte and plasma Se, Cu, Zn were lower in children with ESRD than in controls. In the HD group, the activity of GSH-Px, CAT, and levels of trace elements in erythrocytes and in plasma were diminished at time T²⁰. In conclusion, increased oxidative stress occurs in children on maintenance dialysis, independent of dialysis modality. The activity of the enzymatic antioxidant defence system is highly reduced in red blood cells of pediatric dialysis patients. Children with ESRD exhibit lower trace element (Se, Cu, Zn) levels in plasma and erythrocytes as compared to healthy subjects. Oxidative stress is aggravated during every single HD session in children.     

Reperfusion injury of the liver: role of mitochondria and protection by glutathione ester.

BACKGROUND: Reperfusion injury of the liver is characterized by intravascular oxidative stress and GSH consumption. Whether mitochondria contribute to hepatocellular damage has never been elucidated. Therefore, we assessed mitochondrial function and redox state during reperfusion and the effect of glutathione monoethyl ester (GSHE) administration, which may replenish the GSH pool. MATERIALS AND METHODS: Rats were subjected to partial hepatic ischemia (90 min) followed by reperfusion. Mitochondrial function was assessed in vivo and in vitro by the KICA breath test and the ATP synthase activity. Just prior to the start of reperfusion, rats received 5 mmol/kg of GSHE or saline iv. ALT, total and oxidized (GSSG) glutathione, GSHE, and CYS were measured in plasma and liver. GSH, GSSG, malondialdehyde (MDA), and carbonyl proteins were measured in mitochondria. The extent of necrosis was also estimated. Sham-operated rats served as controls. RESULTS: Reperfusion markedly increased ALT (>1500 U/L) and doubled the liver content of MDA and carbonyl proteins. Mitochondrial GSH decreased approximately 30%, without increase of GSSG. The in vivo KICA breath test was not significantly impaired by reperfusion. In contrast, both KICA decarboxylation and ATP synthase activity were both reduced by approximately 50% in mitochondria isolated from reperfused livers. GSHE administration significantly decreased ALT ( approximately 40%), protected ATP synthase activity, and reduced the extent of necrosis. Compared to controls, plasma GSHE and plasma GSH at 1 h were lower in rats subjected to ischemia. GSHE was higher in reperfused lobes than in continuously perfused ones and the concentration of GSH was significantly higher in ischemic liver than in untreated animals, indicating that the uptake of GSHE is increased in postischemic liver. GSHE prevented the reperfusion-associated increase of oxidized products in liver and mitochondria. CONCLUSIONS: Reperfusion of ischemic liver is associated with oxidative modifications and functional impairment of mitochondria. GSHE protects against reperfusion injury, possibly by providing intra- and extracellular GSH.