Plasma and erythrocytes antioxidant status and trace element levels in proteinuric patients with moderate glomerular function.

The objective of the study was to investigate the effect of moderate glomerular dysfunction on oxidative stress. We determined the plasma and erythrocyte malondialdehyde (MDA) levels, as a marker of lipid peroxidation, erythrocyte glutathione (GSH) levels and activities of GSH-Px, GSH Red and SOD as an antioxidant enzymes, and plasma trace element levels containing Fe, Cu and Zn in twenty proteinuric patients (6.8 +/- 5.1 g/day) with moderate glomerular function and in 20 anemic control subjects. We found that the erythrocyte and plasma MDA levels and erythrocyte GSH-Px activities were significantly higher (p < 0.001, p < 0.001, p < 0.001, respectively) and the erythrocyte GSH levels and activities of GSH-Red and SOD activities were significantly lower (p < 0.001, p < 0.001, p < 0.001, respectively) in the patients than in the anemic subjects. Plasma Fe and Zn levels were not to be found significantly different in the patients compared to the anemic subjects. But plasma Cu levels were significantly higher in the patients (p < 0.05) when compared with the levels of anemic subjects. This study was concluded that cellular antioxidant activity decreases in proteinuric patients with moderate glomerular function. This may increase lipid peroxidation reactions by causing oxidative stress in erythrocyte membranes.     

Impact of cardiovascular risk factors on oxidative stress and DNA damage in a high risk Mediterranean population

Abstract

The impact of classic cardiovascular risk factors on oxidative stress status in a high-risk cardiovascular Mediterranean population of 527 subjects was estimated. Oxidative stress markers (malondialdehyde, 8-oxo-7′8′-dihydro-2′-deoxyguanosine, oxidized/reduced glutathione ratio) together with the activity of antioxidant enzyme triad (superoxide dismutase, catalase, glutathione peroxidase) were analysed in circulating mononuclear blood cells. Malondialdehyde, oxidized glutathione and the ratio of oxidized to reduced glutathione were significantly higher while catalase and glutathione peroxidase activities were significantly lower in high cardiovascular risk participants than in controls. Statistically significant differences were obtained after additional multivariate control for sex, age, obesity, diabetes, lipids and medications. Among the main cardiovascular risk factors, hypertension was the strongest determinant of oxidative stress in high risk subjects studied at a primary prevention stage.     

Quantitative determination of ortho- and meta-tyrosine as biomarkers of protein oxidative damage in beta-thalassemia

Oxidative stress in thalassemia is caused by secondary iron overload and stems from blood transfusion and increased iron uptake. In this study, we hypothesized that levels of o- and m-tyrosine, products of hydroxyl radical attack on phenylalanine, would be elevated in beta-thalassemia (intermediate). This study represents the first report in which specific markers of protein oxidative damage have been quantified in thalassemia. We used GC/MS to assay o- and m-tyrosine at the femtomole level using only a few microliters of plasma. Levels of both markers were significantly higher in patients with beta-thalassemia than in controls and were positively correlated with serum ferritin, malondialdehyde, superoxide dismutase, glutathione peroxidase and glutathione. We conclude that o- and m-tyrosine are useful biomarkers of oxidative damage to proteins in thalassemia (intermediate) and may also be useful markers in other iron overload diseases. Positive correlations between o- and m-tyrosine levels and malondialdehyde as well as antioxidants such as superoxide dismutase, glutathione peroxidase and glutathione, are indicative of the broad impact of oxidative stress on blood plasma in thalassemia, with up-regulation of antioxidant proteins probably reflecting a homeostatic response to these increased stress levels.     

Effects of statins on oxidative stress

Free oxygen radicals and insufficient antioxidant enzymes have been implicated in the pathogenesis of hypercholesterolemia (HC). Trace elements function as cofactors in antioxidant enzymes. Antioxidant system and trace elements were investigated in many different studies including HC, but these subjects have not been investigated as a whole in these patients. The aim of the present study was to investigate the antioxidative system and trace elements in hypercholesterolemic patients given fluvastatin therapy. We examined malondialdehyde (MDA), copper zinc-superoxide dismutase (CuZn-SOD), and glutathione peroxidase (GSH-Px) activities together with copper (Cu), iron (Fe), and zinc (Zn) levels in erythrocytes of 35 patients with HC and 27 healthy control subjects. It was found that in patients with HC, erythrocyte MDA was significantly higher than those of controls and erythrocyte CuZn-SOD and GSH-Px activities were significantly lower in patients with HC. Erythrocyte iron levels were significantly higher than those of controls, and erythrocyte copper and zinc levels were significantly lower in patients with HC. Plasma lipid levels and the oxidative state were analyzed in statin-treatment groups given fluvastatin therapy before and after a 3-mo treatment period. In conclusion, we found that fluvastatin has significant antioxidant properties and these effects might be very important in managing dyslipidemia by improving endothelial function.     

Melatonin effect on renal oxidative stress under constant light exposure

Recently, numerous studies have shown antioxidant actions of melatonin. Melatonin at both physiological and pharmacological levels stimulates glutathione peroxidase, glutathione reductase and superoxide dismutase activities in the brains of rats and chickens. This study was designed to evaluate the effect of melatonin on nephropathy and oxidative stress under constant light exposure. Nephropathy was induced by adriamycin administered in a single dose (25 mg kg(-1) b.w., i.p.). Melatonin was injected i.p. (1,000 microg kg(-1) b.w./day). Malondialdehyde, reduced glutathione, glutathione peroxidase, glutathione reductase, glutathione transferase, catalase and superoxide dismutase were determined in kidney. Urea, creatinine and total proteins in plasma and proteinuria were evaluated and melatonin was determined. Results show a decrease in melatonin levels. Similar effects occurred with the antioxidant enzyme activities and reduced glutathione. Likewise, adriamycin and constant light induced significant enhancement of malondialdehyde. All changes induced both by adriamycin and constant light were reverted to normal by melatonin administration. Constant light exposure was associated with an increase in oxidative stress and nephropathy induced by adriamycin. Treatment with melatonin decreased lipid peroxides, and permitted a recovery of reduced glutathione, scavenger enzyme activity and parameters of renal function.     

Protective effect of propolis against oxidative stress and immunosuppression induced by oxytetracycline in rainbow trout (Oncorhynchus mykiss, W.)

The aim of this study was to investigate the effects of propolis on oxytetracycline (OTC)-induced oxidative stress and immunosuppression in fish. OTC (100 mg per kg?1 body weight) was orally administered to fish for 14 days. A significant elevation in the level of malondialdehyde, as an index of lipid peroxidation, and reductions in antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) and low molecular weight antioxidant (reduced glutathione) levels were observed in the blood, liver, kidney, spleen, and heart tissues of OTC-treated fish. OTC also had a suppressive effect on specific and non-specific immune system parameters, such as leucocyte counts, oxidative radical production (nitrobluetetrazolium activity), total plasma protein and immunoglobulin levels, and phagocytic activity. Pre-treatment, post-treatment, and simultaneous treatment with propolis (50 mg per kg?1 body weight, orally) attenuated the OTC-induced oxidative stress by significantly decreasing the levels of malondialdehyde in tissues. In addition, propolis significantly increased the level of reduced glutathione and the catalase, glutathione peroxidase, and superoxide dismutase activities. Upon the administration of propolis, the suppressed immune system parameters were significantly increased in fish treated with OTC. The present results suggest that pre-treatment, post-treatment, and simultaneous administration of propolis might alleviate OTC-induced oxidative stress and immunosuppression.     

Osteoblast cytoskeletal modulation in response to compressive stress at physiological levels

In this study we assessed activities of antioxidant enzymes, lipid peroxidation end-products, and nitric oxide (NO) levels in women with postmenopausal osteoporosis (PMO). Relationship between oxidative stress parameters and NO levels with bone mineral density (BMD) and clinical variables influencing bone mass and health related quality of life measures was also investigated in women with PMO. Postmenopausal women (n = 87), aged 40–65, without previous diagnosis or treatment for osteoporosis and independent in daily living activities were included. BMD was measured at the lumbar spine and proximal femur using dual-X-ray absorptiometry (DXA). Erythrocyte catalase (CATe) enzyme activity, erythrocyte and plasma enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and lipid peroxidation end-product malondialdehyde (MDA) and nitrite/nitrate levels, by product of NO were studied. A total of 23 healthy non-porotic women were included as controls. Women with PMO had significantly lower erythrocyte CATe enzyme activity and higher erythrocyte malondialdehyde (MDAe) and erythrocyte nitric oxide (NOe) levels in comparison to controls whereas erythrocyte SODe and GSH-Px enzyme activity was similar. In plasma, osteporotic women had significantly higher SOD enzyme activity and higher MDA levels whereas similar GSH-Px enzyme activity and NO levels compared to non-porotic controls. Significant correlation was found between erythrocyte SODe, CATe enzyme activity and NOe levels with proximal femur BMD. Some of the quality of life scores as pain, mental, and social functions correlated with antioxidant enzyme activities and NO levels. Consequently, oxidative stress markers may be an important indicator for bone loss in postmenopausal women. Further researches assessing the oxidative stress markers and NO in bone tissue and changes with anti-osteoporotic drugs would be valuable to better understand the role of free radicals, antioxidants, and NO in the regulation of bone mass.     

Antioxidant Defenses in Wild Growing Halophyte Crithmum maritimum from Inland and Coastline Populations

Traditional Mediterranean diet includes the halophyte Crithmum maritimum L. (Apiaceae) which can be found in the coastline of the Balearic Islands but also inland. Both areas differed in the environmental conditions, mainly in salinity which can affect the oxidative status of this species. The aim was to evaluate the antioxidant enzyme activities, polyphenols and the lipid peroxidation in leaves of wild C. maritimum growing in a natural coastal area influenced by marine salinity and an inland area without marine influence. The activities of the antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase as well as polyphenol and reduced glutathione content were significantly higher in the samples from coastline population, whereas no significant differences were found in glutathione reductase activity and in malondialdehyde levels. The production of H₂O₂ was also significantly higher in the population from coastline. In conclusion, C. maritimum adapt their antioxidant defense machinery to the different salinity conditions, avoiding the instauration of oxidative stress.     

Effects of organophosphorus insecticide phosphomidon on antioxidant defence components of human erythrocyte and plasma.

Effect of organophosphorus insecticide, phosphomidon (250 and 500 ppm) on human erythrocyte and plasma were studied in vitro to get insight into the cellular antioxidant defence mechanism and malondialdehyde formation. The antioxidant defence system of erythrocyte was altered as evident by depression of glutathione reductase, glucose 6 phosphate dehydrogenase, whereas the level of reduced glutathione, glutathione peroxidase, glutathione-S-transferase, superoxidedismutase and catalase were stimulated. In the case of plasma fraction, glutathione reductase, glutathione peroxidase, glutathione-s-transferase, glucose-6-phosphate dehydrogenase, superoxide dismutase and levels of reduced glutathione were significantly depressed and the malondialdehyde formation and catalase activity were elevated indicating the less adaptive response of plasma to protect it from oxidative damage.     

Plasma values of oxidants and antioxidants in acute brain hemorrhage

The levels of oxidants xanthine oxidase (XO), nitric oxide (NO), and malondialdehyde (MDA) and of the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione reductase (GRD) were determined in plasma within 24 h after onset of hemorrhagic stroke in 17 patients (9 men and 8 women, aged 60.7+/-11.5 yr) and in 20 healthy controls (12 men and 8 women, aged 62.5+/-8.3 yr). Compared to controls, the plasma SOD and total superoxide scavenger activities (TSSA) were significantly lower and the NO levels were significantly higher among the stroke patients. XO showed a slight, nonsignificant increase in the patients, but the levels of MDA, NSSA, GRD, and GSH-Px did not show any significant differences between the two groups. The hemorrhage volume was negatively correlated with the initial score of the Glasgow Coma Scale and a positive correlation with lethal outcome, but it did not correlate significantly with any of the measured parameters. The results suggest that free radicals might play a role in the development of brain injury following brain hemorrhage.     

Comet assay and analysis of micronucleus formation in patients with rheumatoid arthritis

Oxidants play a significant role in causing oxidative stress, which underlies the pathogenesis of rheumatoid arthritis (RA). Genetic factors that predispose individuals to RA are considered to play an important role in the development of the disease. The aim of this study was to determine, by use of the comet assay and the micronucleus (MN) test, whether DNA damage has an effect on the pathogenesis of RA. Furthermore, our aim was to show if there is an association between oxidative stress and DNA damage in RA. This study was conducted between January and June 2010 in the Erzurum Training and Research Hospital. We analyzed lymphocytes from patients with RA (12 in active and 31 in inactive periods) and 30 healthy controls for effects in the comet assay and the MN test. In addition, the levels of malondialdehyde (MDA) and superoxide dismutase (SOD), the activity of glutathione peroxidase (GSH-Px), the erythrocyte sedimentation rate (ESR) and the high-sensitivity C-reactive protein (hs-CRP) rate were determined in all the subjects. The comet-tail length, the MN frequencies and the MDA levels were significantly higher in patients--both in the active and the inactive period--than in the controls. In contrast, the SOD and GSH-Px levels were significantly lower in both patient groups than in the controls. Our results suggest that an increased plasma MDA level and decreased plasma GSH-Px and SOD levels reflect the higher degree of oxidative stress in RA patients, a situation that may impair genetic stability in those patients. Thus, the results suggest that increased DNA damage may play an important role in the pathogenesis of RA.     

Oxidative status and serum leptin levels in obese prepubertal children

The prevalence of obesity in children has increased dramatically over the last 20-30 years in developed countries. The aim of this study was to evaluate the oxidative and antioxidant status and any correlation with leptin in obese prepubertal children. A cross-sectional study was made of healthy children from ten elementary schools in the province of Elazig, Eastern Turkey. Blood samples were drawn from children comprising obese and control groups, on a visit to their school in the morning after an overnight fast. The mean body mass index (BMI) was 24.03 +/- 4.09 kg/m(2) in the obese group and was 17.51 +/- 2.33 kg/m(2) in the control group. Mean plasma leptin concentration was significantly higher in the obese children. Homocysteine and malondialdehyde (MDA) levels were also significantly higher in the obese group. In contrast superoxide dismutase (SOD) and glutathione peroxidase activities were significantly decreased in the obese group (p < 0.001). In conclusion, in prepubertal obese children oxidative stress was increased and MDA and homocysteine levels were well correlated with serum leptin level and BMI. In contrast with the increase in oxidative stress, antioxidant activities of SOD and glutathione peroxidase were decreased in obese prepubertal children.     

Biomarkers of diabetes-associated oxidative stress and antioxidant status in young diabetic patients with or without subclinical complications

The aims of the study were to ascertain the potential role of oxidative stress in the onset of disease-related pathophysiological complications in young type 1 diabetes patients. Indicative parameters of lipoperoxidation, protein oxidation, and changes in antioxidant defense system status were measured in blood samples from 26 young diabetic patients with recently diagnosed (< 6 months) microangiopathy (+DC), 28 diabetic patients without complications (−DC), and 40 healthy age-matched controls (CR). Both diabetic groups presented similar fructosamine and glycated hemoglobin (HbA1c) values. Results showed erythrocyte glutathione peroxidase activity, glutathione content, and plasma β-carotene to be significantly lower in diabetic patients compared with control subjects, but with no significant differences between −DC and +DC groups. Antioxidant enzyme superoxide dismutase activity was significantly higher in the erythrocytes of diabetic patients independently of the presence of microvascular complications. However, the plasma -tocopherol/total lipids ratio was significantly diminished in +DC group compared with −DC (p = .008). Lipid peroxidation indices measured in plasma included malondialdehyde, lipid hydroperoxides, and lipoperoxides, which were significantly elevated in our diabetic patients regardless of the presence of complications. Evidence of oxidative damage to proteins was shown both through the quantification of plasma protein carbonyl levels, which were significantly higher in −DC (0.61 ± 0.09 mmol/mg prot), and higher still in the +DC patients (0.75 ± 0.09 mmol/mg prot) compared with those of controls (0.32 ± 0.03 mmol/mg prot; p < .01) and immunoblot analysis of protein-bound carbonyls. Additionally, a marked increase in protein oxidation was observed in +DC patients through assessment of advanced oxidation protein products (AOPP) considered to be an oxidized albumin index; AOPP values were significantly higher in +DC than in −DC patients (p < .01) and CR (p < .0001). These results point to oxidatively modified proteins as a differential factor possibly related to the pathogenesis of diabetic complications.     

Selenium, glutathione and glutathione peroxidases in blood of patients with chronic liver diseases

Disturbances in the antioxidant system could play a role in pathogenesis of chronic liver disease. The aim of our study was to evaluate the levels/activities of antioxidants in blood of patients with chronic liver disease. We estimated selenium and glutathione concentrations and glutathione peroxidase activities in blood of 59 patients with chronic hepatitis B or C virus infection (group 1) and 64 patients with alcoholic, autoimmune or cryptogenic chronic liver disease (group 2). The results were compared with 50 healthy controls. Whole blood and plasma selenium and red cell glutathione concentrations were significantly lower in the patients compared with the controls. Red cell glutathione peroxidase activity was slightly reduced in both subgroups of group 1 and in group 2 with normal alanine aminotransferase values. Plasma glutathione peroxidase activity was slightly but significantly higher in patients with elevated aminotransferase values. The findings suggest that disturbances in antioxidant parameters in blood of patients with chronic liver disease may be the cause of the peroxidative damage of cells.     

Oxidative status and reduced glutathione levels in premature coronary artery disease and coronary artery disease

Identifying patients at risk of developing premature coronary artery disease (PCAD) which occurs at age below 45 years old and constitutes approximately 7–10% of coronary artery disease (CAD) worldwide remains a problem. Oxidative stress has been proposed as a crucial step in the early development of PCAD. This study was conducted to determine the oxidative status of PCAD in comparison to CAD patients. PCAD (<45 years old) and CAD (>60 years old) patients were recruited with age-matched controls (n?=?30, each group). DNA damage score, plasma malondialdehyde (MDA) and protein carbonyl content were measured for oxidative damage markers. Antioxidants such as erythrocyte glutathione (GSH), oxidised glutathione (GSSG), and glutathione peroxidase activity (GPx), superoxide dismutase (SOD) and catalase (CAT) were also determined. DNA damage score and protein carbonyl content were significantly higher in both PCAD and CAD when compared to age-matched controls while MDA level was increased only in PCAD (p<.05). In contrast, GSH, GSH/GSSG ratio, α-tocotrienol isomer, and GPx activity were significantly decreased, but only in PCAD when compared to age-matched controls. The decrease in GSH was associated with PCAD (OR?=?0.569 95%CI [0.375???0.864], p?=?.008) and cut-off values of 6.69?μM with areas under the ROC curves (AUROC) 95%CI: 0.88 [0.80–0.96] (sensitivity of 83.3%; specificity of 80%). However, there were no significant differences in SOD and CAT activities in all groups. A higher level of oxidative stress indicated by elevated MDA levels and low levels of GSH, α-tocotrienol and GPx activity in patients below 45 years old may play a role in the development of PCAD and has potential as biomarkers for PCAD.     

The effects of isosorbide dinitrate on methemoglobin reductase enzyme activity and antioxidant states

Isosorbide dinitrate (ISDN) has been used in the treatment of ischaemic cardiovascular diseases for many years. ISDN is the most popular nitric oxide donor and causes methemoglobinemia as an important side-effect. The purpose of this study was to examine antioxidant states and methemoglobin reductase activity after giving ISDN and ISDN plus vitamin E. Rats were divided into three groups according to the treatment: control group, ISDN group and ISDN plus vit. E group. We measured reduced glutathione in blood (GSH), plasma malondialdehyde (MDA), erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and NADH-dependent methemoglobin reductase activities. In the ISDN group, plasma MDA levels were significantly high compared to the control and ISDN + vit. E groups (p < 0.001). In the ISDN and ISDN + vit. E groups, blood GSH levels were higher than those of the control group (p < 0.05). Changes of SOD and GPx activities were not significant. In the ISDN and ISDN + vit. E groups the erythrocyte catalase and NADH-dependent methemoglobin reductase activities were significantly higher than that in the control group (p < 0.001). We conclude that oxidant drugs such as ISDN need to be carefully used because of lipid peroxidation and methemoglobinemia. These findings support the notion that vitamine E protects tissues against oxidative stress.     

The effect of lycopene on oxytetracycline-induced oxidative stress and immunosuppression in rainbow trout (Oncorhynchus mykiss, W.)

The aim of this study was to determine the effects of lycopene on oxytetracycline (OTC)-induced oxidative stress and immunosuppression in rainbow trout. The experimental fish analysed in this study were divided into 6 different experimental groups. Group 1 was the control group, and groups 2, 3 and 4 received corn oil, lycopene and OTC, respectively, for 14 days. Group 5 received OTC for 14 days after lycopene pre-treatment for 14 days, while group 6 received OTC for 14 days before lycopene post-treatment for 14 days. Blood and tissue samples were collected at the end of the experiment and analysed for the oxidant-antioxidant status and changes in the immune response. There was a significant increase in the malondialdehyde level, which is an index of lipid peroxidation, and a decrease in superoxide dismutase, catalase, and glutathione peroxidase activity as well as a decrease in the glutathione level in the blood, liver, kidney and spleen of OTC-treated fish. Glutathione-S-transferase activity was significantly increased in the blood, liver, kidney and spleen samples of the group that received OTC alone. OTC also appeared to suppress specific and nonspecific immune system parameters, such as the haematocrit, leucocyte count, oxidative radical production (nitroblue tetrazolium activity), total plasma protein and immunoglobulin levels and phagocytic activity. Pre- and post-treatment with lycopene attenuated the OTC-induced oxidative stress by significantly decreasing the tissue malondialdehyde level. The superoxide dismutase, catalase and glutathione peroxidase activities as well as the glutathione levels were significantly increased with lycopene administration, while glutathione-S-transferase activity was significantly decreased. Lycopene administration was also associated with a significant increase in the OTC-suppressed immune system parameters in fish. Thus, the present results suggest that pre- and post-treatment with lycopene (10 mg per kg fish weight, delivered orally) may alleviate OTC-induced oxidative stress and immunosuppression.     

Oxidation products and antioxidant markers in plasma of patients with Graves' disease and toxic multinodular goiter: effect of methimazole treatment

Oxidative stress plays an important role in hyperthyroidism-induced tissue damage, as well as in development of autoimmune disorders. To clarify influence of thyroid metabolic status and autoimmune factors on blood extracellular indices of reactive oxygen species (ROS) generation and free radical scavenging in hyperthyroidism, we studied patients with newly diagnosed and untreated Graves' disease without infiltrative ophthalmopathy (17 female and 8 male, aged 41.8±8.9) and toxic multinodular goiter (15 female and 9 male, aged 48.4±10.1) under the same antithyroid treatment protocol. Initially and after achievement of stable euthyroidism with methimazole, plasma levels of hydrogen peroxide (H₂O₂), lipid hydroperoxides (ROOH) and ceruloplasmin (CP) and serum concentrations of thiobarbituric acid-reacting substances (TBARS) were determined. Similarly, activities of plasma superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) were assayed. The results were compared to those of age- and sex-matched controls. Average duration of hyperthyroidism and treatment period were similar in both patients groups. H₂O₂, ROOH and TBARS concentrations were significantly higher in hyperthyroid patients compared to controls. Hyperthyroidism caused an evident increase in SOD and CAT activities and CP level, as well as a decrease in GPx and GR activities. Achievement of euthyroidism resulted in normalization of all analyzed parameters in both hyperthyroid patients groups. These findings suggest that the changes in blood extracellular indices of oxidative stress and free radical scavenging in hyperthyroid patients are influenced by thyroid metabolic status, and are not directly dependent on autoimmune factors present in Graves' disease.     

Increased oxidative stress is correlated with mitochondrial dysfunction in chagasic patients

Previously, we have shown in an experimental model of Trypanosoma cruzi infection that increased oxidative stress and antioxidant insufficiency are associated with myocardial (cellular and mitochondrial) oxidative damage and mitochondrial functional decline and might be of pathological significance in Chagas disease. In the present study, we investigated whether enhanced oxidative stress and mitochondrial functional decline are found in human chagasic patients. Our data show substantially higher plasma (two-four-fold) and mitochondrial (67%) malonylaldehyde (MDA) levels in chagasic (n = 80, group 2) compared to healthy (n = 50, group 1) subjects. Moreover, antioxidant defense was compromised in chagasic patients. Hence, we noted a 50% decline in glutathione content and losses of 31, 60, and 68% in glutathione peroxidase, superoxide dismutase (SOD), and MnSOD activities, respectively, relative to the findings in healthy controls. Further, chagasic subjects exhibited decreased mitochondrial respiratory complex (CI: 72%; CIII: 71%) activities. Nonchagasic cardiomyopathy subjects (n = 20, group 3) exhibited marginally higher plasma MDA levels compared to gp1 subjects and were not compromised in plasma antioxidant defense capacity. These data suggest that human chagasic patients sustain an antioxidant/oxidant imbalance and a mitochondrial decline of respiratory complex activities in the circulatory system. A positive correlation between increased MDA levels, MnSOD decline, and inhibition of respiratory complexes suggests that oxidative stress may contribute to mitochondrial dysfunction in chagasic patients.     

Antioxidant capacity responsible for a hypocholesterolemia is independent of dietary cholesterol in adult rats fed rice protein

Dietary cholesterol and aging are major risk factors to accelerate oxidation process for developing hypercholesterolemia. The major aim of this study is to elucidate the effects of rice protein on cholesterol level and oxidative stress in adult rats fed with and without cholesterol. After 2 weeks of feeding, hepatic and plasma contents of cholesterol, reduced glutathione (GSH), oxidized glutathione (GSSG), malondialdehyde (MDA) and protein carbonyl (PCO) were measured. In liver, total antioxidative capacity (T-AOC), activities of antioxidant enzymes (total superoxide dismutase, T-SOD; catalase, CAT), glutathione metabolizing enzyme activities and gene expression levels (γ-glutamylcysteine synthetase, γ-GCS; glutathione reductase, GR; glutathione peroxidase, GPx) were determined. Under cholesterol-free/enriched dietary condition, T-AOC, activities of T-SOD and CAT, glutathione metabolism related enzymes' activities and mRNA levels (γ-GCS, GR and GPx) were effectively stimulated by rice proteins as compared to caseins. Compared with caseins, rice proteins significantly increased hepatic and plasma GSH contents, whereas hepatic and plasma accumulations of MDA, PCO and GSSG were significantly reduced by rice protein-feedings. As a result, the marked reductions of cholesterol in the plasma and in the liver were observed in adult rats fed rice proteins with and without cholesterol. The present study demonstrates that the hypocholesterolemic effect of rice protein is attributable to inducing antioxidative response and depressing oxidative damage in adult rats fed cholesterol-free/enriched diets. Results suggest that the antioxidant capability involved in the hypocholesterolemic action exerted by rice protein is independent of dietary cholesterol during adult period.