Antioxidant therapy by oral vitamin E and vitamin E-coated dialyzer in CAPD and haemodialysis patients.

Oxidative stress, increased lipid peroxidation, and impaired function of antioxidant system may contribute to the accelerated development of atherosclerosis in chronic renal failure patients during renal replacement therapy. The aim of the study was to investigate the influence of oral vitamin E (400 mg/day) in 14 patients who underwent continuous ambulatory peritoneal dialysis (CAPD) and effects of the vitamin E-coated dialyzer in 14 haemodialysis patients on several antioxidant biochemical parameters. Six-week treatment with oral vitamin E in CAPD patients and three-month treatment using vitamin E-coated dialyzer in haemodialysis patients led to the significant decrease of plasma malondialdehyde, to the increase of plasma vitamin E and to the increase of erythrocyte vitamin E in haemodialysis patients. No significant changes of erythrocyte antioxidant enzyme--superoxide dismutase, glutathione peroxidase and catalase were found during the both types of antioxidant therapy. At the end of the third month of haemodialysis study the significant increase of erythrocyte glutathione in haemodialysis patients was found, but that value was significantly lower as normal range. Six-week interruption of the administration of oral vitamin E in CAPD patients led to the significant decrease of erythrocyte superoxide dismutase and plasma vitamin E. Ten-week interruption of the use of vitamin E-coated dialyzer led to the significant increase of plasma malondialdehyde and to the decrease of plasma and erythrocyte vitamin E in haemodialysis patients, near to the values at the beginning of the study. Our study confirmed the beneficial effect of oral administration of vitamin E and the use of vitamin E-coated dialyzer against oxidative stress in CAPD and haemodialysis patients.

Changes in ascorbic acid and malondialdehyde in rats after exposure to mercury.

BACKGROUND: Mercury is one of the ubiquitous pollutants participating in generation of reactive oxygen species leading to the formation of oxidative stress. METHODS: Changes in plasma concentrations of ascorbic acid and malondialdehyde were measured in rats after per os exposure to different doses of mercury (as mercuric chloride) for 30 d. RESULTS: The production of ascorbic acid and malondialdehyde was related to the dosage of mercuric chloride. Within the group of rats receiving mercuric chloride in the concentration of 10 micromol/L (corresponding to the LD50 of HgCl2), the concentrations of ascorbic acid and malondialdehyde were increased by 22.19 % and by 6.88 % respectively when compared with the control group. The doses of mercuric chloride lower than LD50 reduced the production of ascorbic acid and malondialdehyde statistically. CONCLUSIONS: Mercury is one of the inducers of oxidative stress in plasma of rats. The oxidation damage caused by mercuric chloride is proven by increased malondialdehyde formation and subsequently compensated by an overproduction of ascorbic acid (Tab. 3, Ref. 22).

Total antioxidant capacity of serum and prognostic indices in patients with burn trauma.

Burn trauma leads to increased production of reactive oxygen species and compromises the antioxidant systems. The aim of present study was to assess the total antioxidant capacity of plasma (TAC) in burn patients and evaluate its usefulness in clinical practice through analysis of association between TAC and indices of patient prognosis. We investigated TAC in 48 adults and 27 children with severe burn trauma and in 26 healthy controls. TAC was measured on the admission and every week thereafter until discharge or death of patients. The prognosis of the patients was evaluated by the Baux Index and the Abbreviated Burn Severity Index (ABSI). TAC was significantly decreased in both groups with burn trauma as compared with the controls and the decrease was a long lasting event. Significant indirect negative correlation was found between BSAB and TAC values measured in the later phase of injury. In adults an indirect correlation was found between ABSI and the lowest TAC measured on the 7th day or later. Correlations between TAC values and Baux Index were absent both in adults and in children.

Vitamin E as an antioxidant agent in CAPD patients.

Oxidative stress, increased lipid peroxidation and decreased activity of antioxidant systems may contribute to the accelerated development of atherosclerosis in chronic renal failure patients during renal replacement therapy. The aim of the study was to investigate the influence of vitamin E (400 mg/day) on some antioxidant defense parameters in CAPD patients. In fourteen CAPD patients, erythrocyte antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT), the concentration of plasma malondialdehyde (MDA), vitamin A, vitamin C and vitamin E were investigated. The study was divided into two periods. Each period lasted six weeks. In the first period patients received orally vitamin E 400 mg/day, in the second period they did not receive vitamin E or other antioxidant drugs. Each parameter was determined at the beginning of the study and at the end of each period. Six CAPD patients were treated by erythropoietin (EPO) and received orally pyridoxine 20 mg/day and the others without EPO treatment received pyridoxine 5 mg/day. Six-week treatment by vitamin E (400 mg/day) led to the significant increase of serum vitamin E (from 33.6+/-9.0 to 49.3+/-15.5 micromol/L) and to the significant decrease of MDA (from 2.62+/-0.5 to 2.36+/-0.4 micromol/L). The mean values of erythrocyte enzymes were in or under the lower margin of normal range and were not influenced by vitamin E in CAPD patients. The results of our study showed that orally administered vitamin E is a very important antioxidant agent for CAPD patients.

A modified dialyzer with vitamin E and antioxidant defense parameters.

BACKGROUND: Oxidative stress, increased lipid peroxidation, and decreased activity of antioxidant systems may contribute to the accelerated development of atherosclerosis in patients receiving hemodialysis therapy for chronic renal failure. We investigated the influence of vitamin E on antioxidant defense parameters in hemodialysis patients who were using a modified dialyzer. METHODS: In eight hemodialyzed patients, erythrocyte antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPX), plasma total antioxidant capacity (TAC), the concentration of plasma malondialdehyde (MDA), and vitamins A, E, and C were investigated. Each parameter was measured before and after hemodialysis. The study was divided into three periods. Each period lasted three weeks, and during this time, 10 hemodialyses were performed. The first and second periods were carried out using the conventional dialyzer, Terumo CL-S15, but during the second period, patients received vitamin E 400 mg perorally after each hemodialysis. The third period was carried out using a modified dialyzer with vitamin E, Terumo CL-E15. All hemodialyzed patients were treated by erythropoietin and received vitamin C 50 mg/day and pyridoxine 20 mg/day during the entire study. RESULTS: The peroral administration of vitamin E led to a significant increase of serum vitamin E (22%), and no influence on other antioxidant defense parameters was found. The modified dialyzer with vitamin E led to a significant increase of serum vitamin E (33%) and TAC and to the significant decrease of plasma MDA. CONCLUSION: The results of our study suggest that the modified dialyzer with vitamin E provided more effective antioxidant defense than peroral administration of vitamin E in our hemodialysis patients.

[Relation between metabolism of trace elements and the antioxidant defense system in chronic nephropathies]. / Vztah medzi metabolizmom stopových prvkov a obranným antioxidacným systémom pri chronických nefropatiách.

BACKGROUND: Trace elements--zinc, copper and selenium are part of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GHPx). In renal diseases changes in the trace element metabolism may influence the equilibrium in the antioxidant defence system and enhance the toxic effect of reactive oxygen molecules. METHODS AND RESULTS: The authors examined in 53 children with chronic neprophathies (34 with chronic glomerulonephritis, 11 with chronic renal failure and 8 children included in a chronic dialyzation programme) zinc and selenium in blood and urine and antioxidant enzymes SOD and GHPx in red blood cells. The lowest SOD activity (737 +/- 219 U/g Hb, p < 0.01) and serum zinc concentration (12.9 +/- 3.2, p < 0.05) were found in children in the terminal stage of uraemia, GHPx was as compared with the group of healthy children elevated in all groups of sick children. In dialysed children GHPx was highest (p < 0.01) and correlated with urinary selenium concentrations (r = -0.86, p < 0.05). The SOD activity depended on the serum copper concentrations (r = 0.78, p < 0.05). The highest renal zinc and selenium excretion was recorded in patients with glomerulonephritis (p < 0.05). CONCLUSIONS: The results support the hypothesis on a causal relationship between trace elements and antioxidant enzymes.

[Antioxidant enzyme activity in erythrocytes in children with kidney diseases]. / Aktivita antioxidacných enzýmov v erytrocytoch u detí s oblickovými chorobami.

BACKGROUND: An important place is ascribed to the formation and action of free oxygen radicals in the pathogenesis of some kidney diseases. The objective of the present work was to examine the antioxidant enzyme defence mechanism in children with different nephropathies. METHODS AND RESULTS: In a group of 58 children (32 boys and 26 girls, mean age 13.9 years) with different renal diseases (35 children with chronic glomerulonephritis-GN, 8 children with a relapse of the nephrotic syndrome and 15 patients with chronic renal insufficiency-CHRI) the concentration of superoxide dismutase and catalase (KAT) was examined. The SOD and KAT activity in erythrocytes was assessed spectrophotometrically at 240 nm. In the whole group of patients the mean SOD values (632 +/- 102 U/g Hb) and KAT values (3.29 +/- 0.54 mukat/g Hb) were within the reference range. The highest mean SOD and KAT values were recorded in children with a relapse of nephrotic syndrome. In the group with chronic GN the SOD concentration in erythrocytes correlated significantly with total protein levels and serum creatinine resp. (r = 0.350, p < 0.05 and r = -0.458, p < 0.01 resp.). In the CHRI stage the authors revealed a significant relationship between the SOD activity and total protein levels (r = 0.550, p < 0.05). CONCLUSIONS: The activity of basic antioxidant enzymes SOD and KAT in erythrocytes of children with nephropathies is not significantly reduced. In patients with chronic GN there is a significant correlation between renal functions and SOD.

Glutathione peroxidase in blood of diabetic and nondiabetic BB rats.

The activity of glutathione peroxidase (GPX), an antioxidant selenoenzyme (EC.1.11.1.9.), was investigated in blood of BB rats developing spontaneous diabetes mellitus. The activity of the enzyme was significantly higher in the 4th and 5th inbred generation (G(4-5)) of BB rats as compared with their counterparts of lower degree of inbreeding (G(1-3)). Overt diabetes (actual blood glucose over 10 mM) appeared only in 8 out of 25 G(5) animals but oral and intravenous glucose tolerance tests revealed a gradual worsening of glucose metabolism already in rats with lower degree of inbreeding. No difference in GPX activity was found between diabetic and nondiabetic members of G(5) group. In the whole group of 69 rats positive correlation was found between the blood GPX activity and the age, weight and actual blood glucose value of the rats and negative correlation between GPX and the P/F value (ratio of peak blood glucose after intravenous tolerance test and fasting blood glucose). In the diabetic animals the enzyme activity showed inverse relationships with every measured or calculated parameter of glucose metabolism. Our findings indicate a relationship between age and blood GPX activity of BB rats and suggest the possibility of deleterious effect of elevated blood glucose level on the blood GPX activity after development of overt diabetes.