The effect of vitamin E therapy on plasma and erythrocyte lipid peroxidation in chronic hemodialysis patients

The effect of vitamin E therapy on plasma and erythrocyte (RBC) lipid peroxidation was investigated in patients undergoing chronic hemodialysis. Before vitamin E therapy, both plasma and RBC lipid peroxidation values of chronic hemodialysis patients were significantly higher than those of healthy controls. Treatment with vitamin E (300 mg/day) for 1 month resulted in a significant decrease of lipid peroxidation. Vitamin E therapy may be a promising approach to prevent peroxidation of membrane lipids in chronic renal failure.     

Lipid peroxidation in hemodialysis patients: effect of vitamin C supplementation

OBJECTIVES: Renal failure is associated with several metabolic disturbances and increasing evidences support a role of oxidative stress and impaired antioxidant defence in the pathologic mechanisms that may contribute to accelerated atherogenesis in these patients. Aim of the study was to further investigate the relationship between oxidative stress and chronic renal failure. DESIGN AND METHODS: We compared the paraoxonase (PON1) activity, the levels of lipid hydroperoxides and AGE adducts in plasma of hemodialysis patients before and after intravenous administration of vitamin C. RESULTS: An increase in lipid hydroperoxides, AGE adducts and a decrease in the activity of PON1 were observed in patients with respect to controls. The comparison before and after supplementation with vitamin C showed an increase of PON1 activity and a decrease of AGE and lipid hydroperoxides levels. CONCLUSIONS: The results provide further evidence that lipid peroxidation and impairment of antioxidant system in plasma of patients may play a role in renal disease and suggest that evaluation of PON1 activity could represents an useful approach to monitor antioxidant treatment and new dialysis therapies.     

Erythrocyte antioxidant enzyme activities and lipid peroxidation in patients with types IIb and IV hyperlipoproteinemias

We measured lipid peroxidation and antioxidant enzymes in erythrocytes of types IIb and IV hyperlipoproteinemic (HLP) human subjects in comparison with age-matched controls. Thiobarbituric acid-reactive substances (TBARS), a measure of lipid peroxidation, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT) were determined in erythrocytes. We also measured lipid parameters including triglycerides (TG), total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), apolipoprotein AI, and apolipoprotein B, and antioxidant related substances such as serum albumin, free iron, ferritin, ceruloplasmin. Thirty-two subjects (females 15, males 17) with type IIb (the mean age 45.6+/-8 [S.E.]), 34 with type IV (females 16, males 18) (the mean age 47+/-10 [S.E.]), and 36 normolipidemic voluntary subjects (females 18, males 18) (the mean age 46+/-8 [S.E.]) were included in the study. Erythrocytes were prepared by classical washing method (0.9% NaCl) from venous blood samples. The mean TBARS levels in plasma and erythrocyte suspensions were found to be significantly higher in both types IIb and IV hyperlipoproteinemics. Erythrocyte SOD and GSH-Px activities were decreased but erythrocyte GR activity did not change in both types IIb and IV hyperlipoproteinemics. Erythrocyte CAT activity was decreased in type IIb, but it was increased in type IV hyperlipoproteinemics. Erythrocyte SOD activity was negatively correlated with plasma TG level, whereas plasma free iron was positively correlated with plasma TBARS level in type IV hyperlipoproteinemics. These results suggest the presence of oxidative injury in patients with type IIb or IV hyperlipoproteinemia, and that the responses of erythrocyte antioxidant enzymes to oxidant stress are different in these conditions.     

Effect of fish-oil and vitamin E supplementation on lipid peroxidation and whole-blood aggregation in man

Free-living, healthy young men aged 21-35 years were divided into two groups, each group received dietary supplements of 15 g/day of fish-oil in the form of MaxEPA capsules, with or without an extra 400 I.U. of vitamin E, for two periods of four weeks. Blood samples were taken from an antecubital vein at two-week intervals. Plasma thiobarbituric acid reactive substances, conjugated dienes, vitamin E, creatine kinase, glucose and serum cholesterol were determined. Whole blood aggregation in response to collagen was determined by an electrical impedance method. Fish oil supplementation increased plasma thiobarbituric acid reactive substances after two weeks in vitamin E supplemented and non-supplemented groups but values returned to normal after four weeks in both groups regardless of the type of supplement given. No comparable increase in plasma conjugated dienes, creatine kinase or serum cholesterol was observed, the latter did not change significantly with diet. Plasma glucose increased when fish oil was supplemented, but only in the absence and not in the presence, of vitamin E supplementation. Whole blood aggregation decreased with the dietary fish oil in the presence, but increased in the absence, of vitamin E supplementation. These findings indicate an increased requirement for dietary antioxidant with high intakes of fish oil concentrates in man.     

Effects of trimetazidine on lipid peroxidation, antioxidant enzyme activities and plasma brain natriuretic peptide levels in patients with chronic cor pulmonale

An oxidant/antioxidant imbalance in favour of oxidants appears to occur in chronic cor pulmonale (CCP). Oxidative stress could also be a critical event in the pathogenesis of this condition. Trimetazidine (TMZ) has antioxidant properties and may affect the utilization of oxygen radicals. We investigated the effect of TMZ (20 mg three times daily, orally) on activities of erythrocyte malondialdehyde (MDA) and catalase (eCAT), erythrocyte and plasma glutathione peroxidase (GSH-Px) and plasma superoxide dismutase (pSOD) in CCP patients. We also assessed changes in plasma levels of brain natriuretic peptide (BNP) with TMZ therapy. Sixty CCP patients with significantly higher MDA and markedly lower pSOD, eCAT and GSH-Px (erythrocyte) activities than 24 healthy controls were randomly allocated to receive routine treatment or routine treatment plus TMZ. After 3 months' therapy, greater pSOD, eCAT and GSH-Px (erythrocyte and plasma) activities and lower MDA activity were found with TMZ treatment compared with routine treatment. Plasma BNP levels were significantly lower in TMZ-treated patients and higher in the routine treatment group than in the control group. TMZ improved antioxidant levels, decreased oxidative stress and decreased plasma BNP levels in CCP patients.     

Antioxidant enzyme activities and lipid peroxidation levels in erythrocytes of patients with oesophageal and gastric cancer

In this study, levels of lipid peroxidation and antioxidant enzyme activities were investigated in the erythrocytes of patients with oesophageal and gastric cancers. Erythrocytes were obtained from 17 patients with oesophageal cancer, 37 patients with gastric cancer and 20 healthy controls. Levels of malondialdehyde (MDA), a lipid peroxidation marker, and activities of copper- and zinc-containing superoxide dismutase (CuZn-SOD), catalase (CAT) and glutathione peroxidase (GPx) were determined using spectrophotometric methods. MDA levels and CuZn-SOD activity were significantly higher and GPx and CAT activities significantly lower in patients with oesophageal and gastric cancer than in controls. There were no statistically significant differences in the parameters measured in relation to disease stage in either patient group. These results indicate significant changes in the antioxidant defence system in patients with oesophageal and gastric cancer. It is postulated that this may lead to enhanced action of oxygen radicals, resulting in lipid peroxidation.     

Plasma total antioxidant capacity, lipid peroxidation, and erythrocyte antioxidant enzyme activities in patients with rheumatoid arthritis and osteoarthritis

OBJECTIVES: The metabolism of cells in inflammatory and noninflammatory arthritic joint diseases is subject to complex environmental controls. The aim of the present study was to investigate the total antioxidant capacity (TAC), levels of lipid peroxidation (LPO), and antioxidant enzyme activities in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). DESIGN AND METHODS: Plasma levels of TAC, malondialdehyde (MDA), the activities of some erythrocyte antioxidant enzymes, as well as erythrocyte sedimentation rates (ESR) were estimated in patients with RA and OA and compared with controls. RESULTS: The plasma TAC levels were significantly lower in the RA group than the OA and control group (P < 0.05). Plasma MDA concentrations were significantly higher in patients with RA than those with OA and healthy subjects (P < 0.05). Erythrocyte GSH-Px and CAT activities were found to be significantly lower in patients with RA than those with OA and healthy subjects (P < 0.05, P < 0.05, respectively). However, there were no significant differences in erythrocyte SOD activities between the groups (P > 0.05). ESR were significantly higher in RA patients than in healthy subjects and patients with OA (P < 0.01). Moreover, there were significant negative correlations between TAC vs. MDA, ESR vs. TAC, and a positive correlation between ESR vs. MDA in the RA group (r = -0.398, P < 0.05; r = -0.422, P < 0.05; r = 0.530, P < 0.05, respectively). CONCLUSIONS: Our results demonstrated that levels of LPO are increased in patients with RA compared to patients with OA. In addition, plasma TAC levels are decreased in RA due to its inflammatory character. We conclude that detecting plasma TAC levels with this novel method may be used as a routine and rapid test to verify the levels of oxidative stress in RA. Furthermore, correlating TAC and LPO levels with acute phase reactants such as ESR may give some clues about disease activity in RA.     

Effects of propylthiouracil, propranolol, and vitamin E on lipid peroxidation and antioxidant status in hyperthyroid patients.

OBJECTIVE: The purpose of this study was to examine lipid peroxidation and antioxidant states during hyperthyroidism states and after given different treatments. DESIGN AND METHODS: We examined 44 hyperthyroid patients and 19 euthyroid healthy controls. Patients were divided into three groups according to the treatment: Propylthiouracil (PTU) group, PTU + propranolol (PRP) group, PTU + PRP + vitamin E (vitE) group. RESULTS: In the hyperthyroid patients plasma malondialdehyde (MDA) levels were significantly high as compared to the control group (p < 0,001).There was a significant decrease in the MDA levels post-treatment (p < 0.001 in the PTU + PRP group and PTU + PRP + vitE group, p < 0.01 in the PTU group). In the hyperthyroidism, blood reduced glutathione (GSH) levels were lower, erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities were higher than in the control group, but these changes were not significant. Post-treatment in each of the three groups the GSH levels were increased significantly as compared to the pretreatment levels (p < 0.001). There was significant decrease in the SOD activity post treatment (p < 0.01 in all three groups). Post-treatment CAT activity was decreased (p < 0.05 in the PTU group, p < 0.001 in the other two groups). The erythrocyte glutathione peroxidase (Gpx) activity was lower significantly in the hyperthyroidism as compared to the control group (p < 0.001). Post-treatment, in the three groups Gpx activity increased significantly as compared to the pretreatment levels (p < 0.05 in the PTU group, p < 0.001 in the PTU + PRP group and PTU + PRP + vitE group). CONCLUSION: We considered that giving all three treatments would be useful to the prevention of oxidative stress in the hyperthyroidism states.     

Effect of pentylenetetrazol-induced epileptic seizure on the antioxidant enzyme activities, glutathione and lipid peroxidation levels in rat erythrocytes and liver tissues

OBJECTIVES: In order to clarify whether oxidative stress accompanies epilepsy, we examined the effects of pentylenetetrazol (PTZ)-induced epilepsy on the lipid peroxidation and antioxidant enzyme activities in erythrocytes and liver tissues of adult Wistar rats. MATERIALS AND METHODS: The activities of antioxidative enzymes (glucose-6-phosphate dehydrogenase (G-6-PD)), copper, zinc-superoxide dismutase (Cu,Zn-SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GSH-Px) and the levels of reduced glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS) were measured in erythrocytes and liver tissues of pentylenetetrazol (PTZ)-induced epileptic adult Wistar rats. RESULTS: Single PTZ treatment in a convulsive dose of 50 mg/kg significantly reduced the erythrocyte Cu,Zn-SOD, CAT enzyme activities and GSH levels compared to controls (P < 0.001, P < 0.001, P < 0.05, respectively). Erythrocyte and liver tissue TBARS levels in the epileptic group were significantly higher than controls (P < 0.0001). There was a significant decrease in liver tissue Cu,Zn-SOD activity and GSH levels in the epileptic group (P < 0.0001), whereas significantly higher activities of G-6-PD and Se-GSH-Px were found in the epileptic group. CONCLUSIONS: Our results demonstrate a generalized diminished antioxidant activity and increased TBARS level indicating enhanced oxidative stress in the liver and erythrocytes of epileptic rats. Increased oxidative stress in the liver of epileptic rats might be due to the activation of the recently found glutamate receptors in the liver. These findings suggest that the use of antioxidants with antiepileptic drugs and new drugs such as type-5 metabotropic glutamate receptor (mGlu5) antagonist (MPEP) might protect erythrocytes and liver tissue against anoxic damage and oxidative stress.     

Elevated lipid peroxidation and disturbed antioxidant enzyme activities in plasma and erythrocytes of patients with uterine cervicitis and myoma.

OBJECTIVES: We investigated whether oxidative stress is associated with human uterine cervicitis and uterine myoma. DESIGN AND METHODS: We measured lipid peroxidation and antioxidant enzymes in plasma and erythrocytes of cervicitis patients and myoma patients in comparison with matched controls. Thiobarbituric acid-reactive substances (TBARS), a measure of lipid peroxidation, were determined in plasma; glutathione peroxidase (GSHPx) and catalase in erythrocytes; and superoxide dismutase (SOD) in both plasma and erythrocytes. RESULTS: We showed that plasma TBARS were significantly higher (p < 0.05) in both cervicitis patients and myoma patients than in controls. Plasma TBARS were significantly (and negatively) correlated with plasma and erythrocyte T-SOD activities in cervicitis patients only. Plasma T-SOD activity was significantly lower in both groups of patients than in controls whereas erythrocyte T-SOD activity was only significantly lower in myoma patients. The lowered plasma T-SOD activity in the cervicitis patients was attributed to decreased Mn-SOD activity whereas the lowered plasma T-SOD activity in myoma patients was attributed to decreased activities of both Cu,Zn-SOD and Mn-SOD. Erythrocyte GSHPx activity was 14% higher (p < 0.05) in cervicitis patients and 11% lower (p > 0.05) in myoma patients than in controls; catalase activity was 10% higher (p > 0.05) in cervicitis patients and 13% lower (p > 0.05) in myoma patients than in controls. Neither erythrocyte GSHPx nor catalase activity was significantly correlated with plasma TBARS. CONCLUSIONS: The elevated lipid peroxidation and disturbed antioxidant enzyme activities demonstrate the potential of oxidative injury in patients with uterine cervicitis and myoma.     

Effects of vitamin E and cimetidine on peritonitis-induced lipid peroxidation

To investigate the effects of acute fecal peritonitis on plasma and tissue lipid peroxidation and possible protective effects of vitamin E (Vit E) and cimetidine at 4 h in a rat peritonitis model, four groups were designated as: controls, peritonitis, Vit E and cimetidine. Plasma, liver, lung and kidney thiobarbituric acid reactive substances (TBARS) and conjugated diene (CD) levels were measured to monitor oxidative injury. The present fecal peritonitis model caused a significant elevation in liver TBARS; however, neither Vit E nor cimetidine was effective in preventing TBARS formation. Administration of Vit E and cimetidine caused significant decrements from the peritonitis value in liver and lung CD levels.     

The effect of vitamin E supplementation on biomarkers of endothelial function and inflammation among hemodialysis patients: A double-blinded randomized clinical trial

ObjectivesThe present study was aimed to investigate the effect of alpha-tocopherol supplementation on biomarkers of endothelial function (Intercellular Adhesion Molecule 1 and Vascular Cell Adhesion Protein 1) and inflammatory markers (Interleukin 6 and high-sensitivity C-reactive protein) among the hemodialysis patients.MethodsTo conduct this randomized, double-blinded, and placebo-controlled clinical trial, 49 hemodialysis patients, aged 20–60 years, were recruited and randomly divided into the intervention and control groups. The intervention group (n = 25) received 600 IU alpha-tocopherol soft gels (200 IU three times daily), while the controls (n = 24) consumed the identical placebo soft gels for 10 weeks. At the baseline and end of the study, 7 ml pre-dialysis blood samples were taken from all participants to measure their serum concentrations of ICAM-1, VCAM-1, IL-6, and hs-CRP.ResultsAlpha-tocopherol supplementation reduced the serum levels of ICAM-1 and VCAM-1 significantly (-140.67 ± 57.25 ng/ml vs. -15.97 ± 79.19 ng/ml, P = 0.001 for ICAM-1 and --6.79 ± 4.76 ng/ml vs. 1.02 ± 3.22 ng/ml, P = 0.019 for VCAM-1). However, no significant difference was observed between the two groups regarding the serum levels of hs-CRP (-0.15 ± 0.19 mg/l vs. 0.02 ± 0.12 mg/l; P = 0.32) and IL-6 (-0.03 ± 0.1 pg/ml vs. - 0.06 ± 0.11 pg/ml; P = 0.65).ConclusionsOur results showed that 10 weeks of supplementation with 600 IU alpha-tocopherol improved ICAM-1 and VCAM-1 levels, but did not have any effect on the serum concentration of IL-6 and hs-CRP in hemodialysis patients. Further studies are required to confirm these findings.     

The effect of bilirubin on lipid peroxidation and antioxidant enzymes in cumene hydroperoxide-treated erythrocytes

Recently, it has been suggested that bilirubin may act as a potent biological chain-breaking antioxidant. To observe the effects of free bilirubin on antioxidant reactions in cumene hydroperoxide-treated erythrocytes (15 g hemoglobin/dl), we added bilirubin at four different concentrations (0.5, 1, 5, and 10 mg/dl). We measured the thiobarbituric acid-reactive substance and reduced glutathione levels, and some antioxidant enzyme activities, namely superoxide dismutase, catalase, and glucose-6-phosphate dehydrogenase. Thiobarbituric acid-reactive substance and chemiluminescent signals decreased during the incubation. Superoxide dismutase activities also decreased but not as much as in the control group. Glucose-6-phosphate dehydrogenase activities and reduced glutathione levels increased, but catalase activities remained the same as the control group. Our results suggest that bilirubin — in the concentrations we have used — partially prevented the oxidant effects of cumene hydroperoxide.     

The evaluation of lipid peroxidation and acute effect of octreotide on lipid peroxidation in patients with active acromegaly

BACKGROUND: Although lipid peroxidation has been suggested to play a role in the etiology of many diseases, there is no report about its role in acromegaly in the literature. In the present study, we analyzed the basal levels of lipid peroxides (LPO) in newly diagnosed acromegalic patients, and to evaluate whether octreotide (OCT) has any effect on lipid peroxidation in these patients. METHODS: Plasma lipid peroxide levels before and after acute OCT administration were measured in 12 newly diagnosed acromegalic patients. Blood samples were drawn at basal and 4, 8, and 24 h after octreotide injection (100 microg s.c.). Plasma concentrations of lipid peroxides were estimated from measurement of thiobarbituric acid reactive substance (TBARS), using 1,1,3,3-tetra-ethoxypropane as a standard. RESULTS: This study shows that acromegalic patients have significantly higher basal plasma lipid peroxides levels compared to hours after OCT injection (p<0.001). Although a significant decrease was observed after 8 and 24 h in comparison to basal level (p<0.001), the lipid peroxide levels tended to increase at 24 h though still low when compared to basal level. CONCLUSION: Acromegalic patients have high basal lipid peroxide levels, which was significantly decreased after OCT administration.     

Alternation of hepatic antioxidant enzyme activities and lipid profile in streptozotocin-induced diabetic rats by supplementation of dandelion water extract

BACKGROUND: Dandelion water extract (DWE), an herbal medication, may have an effect on the activity and mRNA expression of hepatic antioxidant enzymes and lipid profile in streptozotocin (STZ)-induced diabetic rats. METHODS: Male Sprague-Dawley rats were divided into nondiabetic (control), diabetic, and diabetic-DWE-supplemented groups. Diabetes was induced by injecting streptozotocin (55 mg/kg BW, i.p.) in a citrate buffer. The extract was supplemented in 2.4 g of a DWE/kg diet. RESULTS: The DWE supplement significantly decreased the serum glucose concentration in the diabetic rats. The hepatic superoxide dismutase and catalase activities significantly increased and the GSH-Px activity decreased in the diabetic rats, compared with the control group. When the DWE supplement was given to the diabetic rats, the antioxidant enzyme activity reverted to near-control values. However, there was no difference in the mRNA expression concentrations of these enzymes between the groups. With regard to the hepatic lipid peroxidation product, the malondialdehyde (MDA) content was significantly higher in the diabetic group than in the nondiabetic group. However, the DWE supplement lowered the hepatic MDA concentration in the diabetic-induced rats. The DWE supplement also lowered the total cholesterol and triglyceride concentrations in the serum and hepatic tissue, while increasing the serum HDL-cholesterol in the diabetic rats. CONCLUSIONS: A DWE supplement can improve the lipid metabolism and is beneficial in preventing diabetic complications from lipid peroxidation and free radicals in diabetic rats.     

Photo-irradiated curcumin supplementation in streptozotocin-induced diabetic rats: effect on lipid peroxidation

BACKGROUND: Diabetes mellitus is one of the most common endocrine disorders. A large number of studies are in progress to identify natural substances that are effective in reducing the severity of diabetes. Although a number of drugs are currently marketed, their long-term use can cause a number of adverse effects. MATERIALS AND METHODS: In the present study, we examined the effect of photo-irradiated curcumin on experimental diabetes in order to evaluate the antihyperglycaemic effects of this compound on streptozotocin (40 mg/kg bodyweight)-induced diabetes. Photo-irradiated curcumin was given at a dose of 10, 30 and 80 mg/kg bodyweight. The level of blood glucose was elevated in the diabetic animals. The liver, kidney and brain were assayed for the degree of lipid peroxidation, reduced glutathione content and the activity of enzymic and levels of non-enzymic antioxidants. RESULTS: Antioxidant status decreased in the diabetic animals. Oral administration of photo-irradiated curcumin for 45 days resulted in a significant decrease in the levels of blood glucose, together with near normalisation of enzymic activity and the markers of lipid peroxidation. The best results were obtained in rats treated with 30 mg/kg bodyweight of photo-irradiated curcumin.     

血清25羟维生素D水平及脂质过氧化对老年颈动脉硬化的影响

目的探讨血清25羟维生素D[25(OH)VitD]及氧化低密度脂蛋白(ox-LDL)、超敏C反应蛋白(hs-CRP)水平与老年颈动脉硬化(CAS)患者的关系。方法收集60岁以上112例住院患者,经彩色多普勒超声诊断仪检查,依据是否存在颈动脉粥样斑块及狭窄,分为颈动脉硬化组(CAS组、52例)和非颈动脉硬化组(CAN组60例)。采用电化学发光法测定血清中25羟维生素D含量,运用全自动生化仪测定hs-CRP水平,采用ELISA方法测定血清ox-LDL水平。分析CAS组与CAN组上述指标的差异性及其与颈动脉粥样硬化的相关性。结果和CAN组相比,CAS组患者血清25(OH)VitD水平降低,ox-LDL、hs-CRP水平明显升高,差异有统计学意义(P0.05)。血清25(OH)VitD与CAS呈负相关(r=-0.617,P0.05);血清氧化低密度脂蛋白(ox-LDL)、超敏C反应蛋白(hs-CRP)与CAS呈正相关(r值分别为r=0.478、r=0.591,P0.05)。结论血清25(OH)VitD水平降低、ox-LDL、hs-CRP水平升高在老年CAS患者中可能是独立的危险因素。     

Lipid peroxidation and antioxidant supplementation in old age

An age-related rise in blood lipid peroxides measured by the thiobarbituric acid (TBA) method has been reported in several studies. Our study was designed to investigate whether this could be attributed to antioxidant deficiencies in aged individuals. We therefore measured the TBA-value of young and old women and related this to vitamin E and selenium status and the fatty acid composition, triglyceride and cholesterol content of platelet-poor plasma. A significant difference (p less than 0.001) between young and old women in the plasma TBA-value and the plasma lipid parameters was found. Old women had a lower selenium status than the young women (p less than 0.01), but their vitamin E status was fully adequate. Only the lipid parameters correlated significantly (p less than 0.001) with the TBA-value. In a 3-month placebo-controlled supplementation trial with vitamin E and selenium, the plasma TBA-value of the old women did not change. This study shows that the TBA-value of plasma is primarily determined by the fatty acid content and is not influenced by antioxidant supplementation in healthy individuals. The question of the sensitivity of the TBA-test is discussed.