Biomarkers Of Protein Oxidation Research Articles

Suppressive effects of Hydroxytyrosol on oxidative stress in erythrocytes

We investigated the oxidative modifications of lipids, proteins and antioxidants enzymes activities, in erythrocytes treated with H2O2 in the presence or absence of hydroxytyrosol (HT) at 37°C for 30 min. Conjugated dienes level was measured as biomarker of lipid peroxidation. Protein carbonyl level was measured as biomarker of protein oxidation. The antioxidants enzymes activities were evaluated by superoxide dismutase and catalase activities determinations. Conjugated dienes levels decreased in erythrocytes after hydroxytyrosol treatment as compared to erythrocytes treated with 0.2 mM H2O2. Protein carbonyl levels increased in erythrocytes after hydroxytyrosol treatment as compared to erythrocytes treated with 0.2 mM H2O2. In addition, this study showed a prospective protective action of HT of human erythrocytes from the attack of reactive oxygen species. In fact, a considerable increase of superoxide dismutase activity by 40% was showed after incubation of erythrocytes with HT at dose 5 µg/ml. Although, there were no significant differences in catalase activity in erythrocytes after hydroxytyrosol treatment as compared to erythrocytes treated with 0.2 mM H2O2. This study demonstrates that hydroxytyrosol prevents protein oxidation and lipid peroxidation caused by H2O2 treatment using erythrocytes cell model. Key words: Hydroxytyrosol, thiol, erythrocytes, conjugated dienes, malondialdehyde, superoxide dismutase, catalase, peripheral blood mononuclear (PBL), peripheral blood mononuclear.

Oxidative Stress in Brain Tissue of Gerbils Experimentally Infected withNeospora caninum

Neospora caninum infection is generally latent and asymptomatic, and it results in the formation of dormant encysted bradyzoites that remain in the brain and other tissues of infected animals for life, causing major economic and pathological problems. The aim of this study was to assess the relation between infection by N. caninum and its damage to brain tissue through the evaluation of biomarkers of oxidative stress during the acute and chronic phases of the disease. Sixteen gerbil (Meriones unguiculatus) were divided into 3 groups: Group A (n = 6) was composed of healthy animals, while group B (n = 5) was infected with 0.1 ml containing 2.5 × 10(6) tachyzoites of N. caninum in order to achieve the acute phase, and, finally, group C (n = 5) was infected with a lower dose (0.1 ml containing 5 × 10(4)) of N. caninum tachyzoites in order to produce the chronic phase of the disease. All evaluations were performed on brain tissue on days 7 and 30 postinfection (PI), with assessment of the levels of several biomarkers of oxidative stress, including nitrate/nitrite (NOx), lipid peroxidation (TBARS), protein oxidation (AOPP), and activity of glutathione reductase (GR). Brain levels of TBARS and AOPP statistically differed (P < 0.05) among the 3 groups when compared to the control group, since both biomarkers showed reduced levels on day 7 PI, and increased levels on day 30 PI. Brain activity of GR increased significantly in animals from group C when compared to groups A and B. On day 7 PI, histological lesions and parasites in the brain were not observed, whereas in the chronic phase group, the infected gerbils (day 30 PI) showed areas of inflammatory infiltrate, accompanied by the presence of the parasite in the brain. These results suggest that the oxidative stress occurs at both time points, but the patterns of the biomarkers are different.

Hydrogen peroxide and nitric oxide trigger redox-related cyst formation in cultures of the dinoflagellate Lingulodinium polyedrum

The dinoflagellate Lingulodinium polyedrum is a toxin producer that shows the ability of turning to resting cysts as a survival strategy when exposed to environmental unfavorable conditions, such as nitrogen and phosphorus depletion, abrupt changes in temperature or light, and chemical or mechanical stress. Algal adaptation to all these conditions involves hydrogen peroxide (H2O2) and nitric oxide (NO) as key redox signals for housekeeping cellular processes. Thus, we aim here to shed light on the role of H2O2 and NO (from aqueous decomposition of sodium nitroprusside, SNP) as prooxidant agents and putative redox signals for encystment of the dinoflagellate L. polyedrum. Harsh oxidative stress imposed by 500μM H2O2 treatment forced L. polyedrum cells to rapidly encyst, in less than 30min, whereas slower cyst formation was observed upon lower H2O2 doses. L. polyedrum encystment was marked by a significant increase in the antioxidant carotenoid peridinin, although other photosynthetic pigments (chlorophyll a and β-carotene) and light-harvesting complexes (peridinin complex protein, PCP) were all diminished in cyst forms. Although SOD activity (a frontline antioxidant enzyme) was severely inhibited by increasing doses of H2O2, a theoretical compensatory effect was provided by the dose-dependent increase of ascorbate peroxidase activity (APX), which resulted in significant lower levels of lipid peroxidation during cyst formation. Although SNP data cannot be fully compared to those found with H2O2 treatments, changes in APX activity and in biomarkers of lipid and protein oxidation matched the dose–responses found in H2O2 experiments, revealing similar biochemical and morphological responses against increasing oxidative conditions during cyst formation. Our data significantly contribute to a better understanding of the relationship between encystment, photosynthesis, and antioxidant responses triggered by H2O2 and NO in L. polyedrum, a harmful diarrhetic shellfish poisoning toxin (DSPs) producer.

Effect of dietary garlic supplementation on lipid peroxidation and protein oxidation biomarkers of tissues as well as some serum biochemical parameters in common carp Cyprinus carpio

This study aims to investigate the effects of dietary garlic powder (25 and 50 g kg−1 feed) supplementation for 6 weeks on lipid and protein oxidation biomarkers in various tissues as well as some blood biochemical parameters in common carp. Based on the present study results, serum malondialdehyde (MDA) concentrations were decreased following garlic supplementation, but the decrease was only significant (P < 0.05) in the group that received 50 g kg−1 dietary garlic compared with the control group. Moreover, garlic at 50 g kg−1 diet caused significant decrease in MDA values of liver and kidney. Additionally, the decreasing effect of garlic at 25 g kg−1 diet on MDA values was only significant in liver. Protein carbonyl contents were only decreased significantly in muscle following garlic administration at 25 g kg−1 diet. Serum aspartate aminotransferase activity decreased significantly in carp that received 25 g kg−1 dietary garlic. Moreover, alkaline phosphatase activity decreased significantly in carp fed diets containing 25 and 50 g kg−1 garlic. On the other hand, garlic supplementation had no significant effect on gamma-glutamyl transferase activity and total protein, albumin, and creatinine concentrations. The results of the present study indicate that garlic powder has potential to decrease oxidative stress to some extent by reducing lipid and protein oxidation in some tissues of common carp.

Sex-Related Effects of Reproduction on Biomarkers of Oxidative Damage in Free-living Barn Swallows (Hirundo rustica)

According to life-history theory, the allocation of limiting resources to one trait has negative consequences for other traits requiring the same resource, resulting in trade-offs among life-history traits, such as reproduction and survival. In vertebrates, oxidative stress is increasingly being considered among the physiological mechanisms forming the currency of life-history trade-offs. In this study of the barn swallow (Hirundo rustica), we focus on the oxidative costs of reproduction, especially egg laying, by investigating the effects of breeding stage (pre- vs. post-laying) and progression of the season on three biomarkers of oxidative damage (OD) to plasma proteins, namely the concentration of malondialdehyde (MDA)-protein adducts and of protein thiol groups (PSH), and the protein carbonyl (PCO) content. Moreover, we investigated whether males and females differed in plasma OD levels, because the inherent sex differences in reproductive roles and physiology may originate sex-specific patterns of OD during breeding. We found that MDA-protein adduct levels were higher in the pre-laying than in the post-laying phase, that males had lower levels of MDA-modified proteins than females, and that the decline of MDA-protein adduct concentration between the pre- and the post-laying phase was more marked for females than males. In addition, MDA-protein adduct levels declined with sampling date, but only during the pre-laying phase. On the other hand, plasma PCO levels increased from the pre- to the post-laying phase in both sexes, and females had higher levels of PCO than males. PSH concentration was unaffected by breeding stage, sex or sampling date. On the whole, our findings indicate that biomarkers of protein oxidation closely track the short-term variation in breeding stage of both male and female barn swallows. Moreover, the higher protein OD levels observed among females compared to males suggest that egg laying entails oxidative costs, which might negatively affect female residual reproductive value.

Effects of ozone therapy on haemostatic and oxidative stress index in coronary artery disease

Coronary artery disease (CAD) is the most common cause of sudden death, and death of people over 20 years of age. Because ozone therapy can activate the antioxidant system and improve blood circulation and oxygen delivery to tissue, the aim of this study was to investigate the therapeutic efficacy of ozone in patients with CAD, treated with antithrombotic therapy, Aspirin® and policosanol. A randomized controlled clinical trial was performed with 53 patients divided into two groups: one (n=27) treated with antithrombotic therapy and other (n=26) treated with antithrombotic therapy plus rectal insufflation of O3. A parallel group (n=50) age and gender matched was used as reference for the experimental variables. The efficacy of the treatments was evaluated by comparing hemostatic indexes and biochemical markers of oxidative stress in both groups after 20 day of treatment. Ozone treatment significantly (P<0.001) improved prothrombin time when compared to the antithrombotic therapy only group, without modifying bleeding time. Combination antithrombotic therapy+O3 improved the antioxidant status of patients reducing biomarkers of protein and lipid oxidation, enhancing total antioxidant status and modulating the level of superoxide dismutase and catalase with a 57% and 32% reduction in superoxide dismutase and catalase activities respectively, moving the redox environment to a status of low production of O2•− with an increase in H2O2 detoxification. No side effects were observed. These results show that medical ozone treatment could be a complementary therapy in the treatment of CAD and its complications.

One year of pomegranate juice intake decreases oxidative stress, inflammation, and incidence of infections in hemodialysis patients: A randomized placebo-controlled trial

Increased systemic inflammation and oxidative stress are well established as nontraditional key players in the pathogenesis of atherosclerosis and are also involved in the innate immunity dysregulation in hemodialysis (HD) patients. The study aim was to investigate the effect of 1-year intake of pomegranate juice, an antioxidant source, on oxidative stress, inflammation, and long-term clinical outcomes. A randomized placebo controlled double-blind trial was designed, enrolling 101 chronic HD patients to receive during each dialysis 100cc of pomegranate juice, or matching placebo, three times a week for 1 year. The primary endpoints were levels of oxidative stress and inflammation biomarkers. Secondary endpoints were hospitalization due to infections and the progression of atherosclerotic process based on a composite of variables of the carotid arteries: intima media thickness (IMT), number, and structure of plaques. Pomegranate juice intake yielded a significant time response reduction in polymorphonuclear leukocyte priming, protein oxidation, lipid oxidation, and inflammation biomarkers levels. These beneficial effects were abolished 3 months postintervention. Pomegranate juice intake resulted in a significantly lower incidence rate of the second hospitalization due to infections. Furthermore, 25% of the patients in the pomegranate juice group had improvement and only 5% progression in the atherosclerotic process, while more than 50% of patients in the placebo group showed progression and none showed any improvement. Prolonged pomegranate juice intake improves nontraditional CV risk factors, attenuates the progression of the atherosclerotic process, strengthens the innate immunity, and thus reduces morbidity among HD patients.

Biomarkers of Protein Oxidation in Human Disease

Oxidative stress is caused by an imbalance between the production of reactive species of oxygen and nitrogen (RS) and the ability to either detoxify the reactive intermediates produced or repair the resulting damage. Ultimately, oxidative stress conveys the alteration in cellular function caused by the reaction of RS with cellular constituents. Oxidative stress has been extensively reported to participate in the progression of a variety of human diseases including cancer, neurodegenerative disorders and diabetes. Oxidation of proteins is thought to be one of the major mechanisms by which oxidative stress is integrated into cellular signal transduction pathways. Thus, recent research efforts have been aimed to identify the role of specific oxidative protein modifications in the signal transduction events mediating the etiology of human diseases progression. The identification of these oxidative modifications has also raised the possibility of using this knowledge to develop new methods to diagnose diseases before they are clinically evident. In this work, we summarize the mechanisms by which RS generate distinct oxidative modifications. Furthermore, we also review the potential of these oxidative modifications to be used as early biomarkers of human disease.

Combined astaxanthin and fish oil supplementation improves glutathione-based redox balance in rat plasma and neutrophils

The present study aimed to investigate the effects of daily (45days) intake of fish oil (FO; 10mg EPA/kg body weight (BW) and 7mg DHA/kg BW) and/or natural ASTA (1mg ASTA/kg BW) on oxidative stress and functional indexes of neutrophils isolated from Wistar rats by monitoring superoxide (O2-), hydrogen peroxide (H2O2), and nitric oxide (NO) production compared to the progression of auto-induced lipid peroxidation and Ca2+ release in activated neutrophils. Furthermore, phagocytic capacity, antioxidant enzyme activities, glutathione-recycling system, and biomarkers of lipid and protein oxidation in neutrophils were compared to the redox status. Our results show evidence of the beneficial effects of FO+ASTA supplementation for immune competence based on the redox balance in plasma (significant increase in GSH-dependent reducing power), non-activated neutrophils (increased activity of the glutathione-recycling enzymes GPx and GR) and PMA-activated neutrophils (lower O2-, H2O2, and NO generation, reduced membrane oxidation, but higher phagocytic activity). Combined application of ASTA and FO promoted hypolipidemic/hypocholesterolemic effects in plasma and resulted in increased phagocytic activity of activated neutrophils when compared with ASTA or FO applied alone. In PMA-activated neutrophils, ASTA was superior to FO in exerting antioxidant effects. The bulk of data reinforces the hypothesis that habitual consumption of marine fish (e.g. salmon, which is a natural source of both astaxanthin and fish oil) is beneficial to human health, in particular by improving immune response and lowering the risk of vascular and infectious diseases.

Ischemia modified albumin and carbonyl protein as potential biomarkers of protein oxidation in hemodialysis

The aim of this study was to evaluate the effect of HD on ischemia modified albumin (IMA) and protein carbonyl groups in order to investigate the role of IMA as a marker of protein oxidation. This study was conducted with 23 chronic hemodialysis patients. The serum IMA levels and protein carbonyl groups were measured immediately before hemodialysis (pre-HD) and after the end of hemodialysis (post-HD). IMA concentrations were significantly higher in post-HD than those of the pre-HD and carbonyl protein concentrations were higher in post-HD in comparison with pre-HD. A significant correlation was observed between IMA and carbonyl protein levels. The increase of IMA levels and protein carbonyl groups post-HD could be attributed to the increase of oxidative stress associated with HD, and IMA appears to be an important biomarker for assessing protein oxidation after HD.

Fish oil and 3-thia fatty acid have additive effects on lipid metabolism but antagonistic effects on oxidative damage when fed to rats for 50 weeks

The 3-thia fatty acid tetradecylthioacetic acid (TTA) is a synthetic modified fatty acid, which, similar with dietary fish oil (FO), influences the regulation of lipid metabolism, the inflammatory response and redox status. This study was aimed to penetrate the difference in TTA's mode of action compared to FO in a long-term experiment (50 weeks of feeding). Male Wistar rats were fed a control, high-fat (25% w/v) diet or a high-fat diet supplemented with either TTA (0.375% w/v) or FO (10% w/v) or their combination. Plasma fatty acid composition, hepatic lipids and expression of relevant genes in the liver and biomarkers of oxidative damage to protein were assessed at the end point of the experiment. Both supplements given in combination demonstrated an additive effect on the decrease in plasma cholesterol levels. The FO diet alone led to removal of plasma cholesterol and a concurrent cholesterol accumulation in liver; however, with TTA cotreatment, the hepatic cholesterol level was significantly reduced. Dietary FO supplementation led to an increased oxidative damage, as seen by biomarkers of protein oxidation and lipoxidation. Tetradecylthioacetic acid administration reduced the levels of these biomarkers confirming its protective role against lipoxidation and protein oxidative damage. Our findings explore the lipid reducing effects of TTA and FO and demonstrate that these bioactive dietary compounds might act in a different manner. The experiment confirms the antioxidant capacity of TTA, showing an improvement in FO-induced oxidative stress.

Hyperammonemia induced oxidative stress in cirrhotic rats without promoting differential protein expression in the brain cortex: A 2D-DIGE analysis

Oxidative stress induced by a high ammonia concentration could modify protein expression in the brain. This study was undertaken in order to investigate the impact of hyperammonemia, caused by thioacetmide (TAA) in rats, on brain cortex protein expression using 2D-DIGE, and analyzing its role in the pathogenesis of HE. Hyperammonemia was induced with TAA. Ammonia and active oxidants were measured by L-glutamate dehydrogenase and dichlorodihydrofluorescein diacetate methods, respectively. Lipid peroxidation and protein oxidation biomarkers were also studied. Differential protein expression in the cortex of TAA- and control-rats was studied by 2D-DIGE. Image analysis was performed using the DeCyder? Software. Ammonia concentration in plasma and brain tissue was higher in TAA-rats compared to control-rats, 3.12 and 2.43 fold higher, respectively. Active oxidants production in TAA-rats was increased by 2.7 fold compared to control-rats. Measurements of MDA, HNE and carbonyl groups, biomarkers of lipid peroxidation and protein oxidation respectively, were found to be statistically significantly increased in TAA-rats compared to control-rats (3.16-, 2.44- and 1.95-fold, respectively), reflecting the presence of oxidative stress in the brain of TAA-rats. 2D-DIGE analysis of brain cortex protein allowed the detection of 2896 spots, however, image analysis showed no statistically significant differential protein expression between the proteins expressed in TAA- and control-rats. No statistical significant differential protein expression in the cortex of TAA-rats was observed, although oxidative stress biomarkers for lipid and proteins were higher in the brain of TAA-rats than in control-rats. These results support the idea that oxidative post-translational modifications are implicated in HE physiopathology.

Comparison of oxidative stress biomarkers in renal tissues of d-galactose induced, naturally aged and young rats

Ageing of kidneys is a clinical health issue of the society. Age-related renal insufficiency has important implications due to impaired redox homeostasis. We examined protein, DNA and lipid oxidation biomarkers as well as protein-bound sialic acid (SA) in the kidney tissues of D-galactose induced ageing rats, naturally aged rats and their corresponding young control group. Intraperitoneal injection of D-galactose (60 mg/kg/day) for 6 weeks to young male Sprague-Dawley rats (20-week-old) was used to establish mimetic ageing model. In this study, we investigated the levels of protein carbonyl groups (PCO), various thiol fractions such as total thiol groups (T-SH), protein (P-SH) and non-protein thiol groups (NP-SH), lipid oxidation parameters such as lipid hydroperoxides (LHP) and malondialdehyde (MDA), SA and 8-hydroxy-2'deoxyguanosine (8-OHdG) parameters for comparison of naturally aged, induced aged and young rats. In D-galactose induced aged group, PCO, LHP, MDA, and 8-OHdG concentrations were significantly higher than young control group, whereas T-SH, P-SH levels were significantly lower than the young rats. In addition, NP-SH and SA concentrations were similar between the mimetic ageing and young control groups. In naturally ageing rats, PCO and MDA levels were significantly higher, whereas T-SH, P-SH, NP-SH concentrations were low compared to young controls. On the other hand, SA and 8-OHdG levels were not different between the naturally ageing group and the young control group. Our results demonstrated that the rats in the mimetic ageing group, have significant similarities with the naturally aged rats in terms of impaired redox homeostasis and can be used as a reliable animal model for renal ageing.

Plasma levels of oxidative stress biomarkers and hospital mortality in severe head injury: A multivariate analysis

IntroductionThe association between biomarkers of oxidative stress and the prognosis of patients with traumatic brain injury (TBI) remains inconclusive. ObjectiveThe objective was to investigate the association between plasma levels of lipid peroxidation (thiobarbituric acid reactive species [TBARS]) and protein oxidation (carbonyl) biomarkers and the hospital mortality of patients with severe TBI. MethodsPlasma levels of TBARS and carbonyl were determined in 79 consecutive patients with severe TBI (Glasgow Coma Scale [GCS] ≤8) at a median of 12 hours (interquartile range [IQ] 25-75, 6.5-19.0), 30 hours (IQ 25-75, 24.7-37.0), and 70 (IQ 25-75, 55.0-78.5) hours after TBI and were compared with age- and sex-matched controls. The association between the TBARS and carbonyl levels and the hospital mortality was analyzed by multiple logistic regression analysis. ResultsThe mean age of patients was 34.8 years. Eighty-six percent were male. The TBARS and carbonyl levels were significantly higher in patients than in controls. There was a trend (P = .09) for higher plasma levels of TBARS and carbonyl proteins at 12 hours, but not at 30 or 70 hours, after trauma in nonsurvivors than in survivors. These findings were not confirmed after the adjustments by multiple logistic regression analysis. The final model showed a higher adjusted odds ratio for death for patients with admission GCS lower than 5 (odds ratio [OR] = 4.04; 95% confidence interval [CI], 1.33-12.13; P = .01) than those with higher GCS scores. Abnormal pupils were also associated with higher mortality (OR = 3.97; 95% CI, 1.22-12.13; P = .02). There was a nonsignificant trend for association between glucose greater than or equal to 150 mm/dL in the first 12 hours and death than levels between 70 and 149 mg/dL (OR = 2.92; 95% CI, 0.96-9.02; P = .06). ConclusionsPlasma levels of TBARS and carbonyl increase significantly in the first 70 hours after severe TBI but are not independently associated with the hospital mortality.

Induction of epstein-barr virus (EBV) lytic cycle in vitro causes lipid peroxidation, protein oxidation and DNA damage in lymphoblastoid B cell lines

BackgroundWe investigated the oxidative modifications of lipids, proteins and DNA, potential molecular targets of oxidative stress, in two lymphoblastoid cell lines: B95-8 and Raji, after EBV lytic cycle induction. Conjugated dienes level was measured as biomarker of lipid peroxidation. Malondialdehyde adduct and protein carbonyl levels, as well as protein thiol levels were measured as biomarkers of protein oxidation. DNA fragmentation was evaluated as biomarker of DNA oxidation.ResultsAfter 48 h (peak of lytic cycle), a significant increase in conjugated dienes level was observed in B95-8 and Raji cell lines (p = 0.0001 and p = 0.019 respectively). Malondialdehyde adduct, protein carbonyl levels were increased in B95-8 and Raji cell lines after EBV lytic cycle induction as compared to controls (MDA-adduct: p = 0.008 and p = 0.006 respectively; Carbonyl: p = 0.003 and p = 0.0039 respectively). Proteins thiol levels were decreased by induction in B95-8 and Raji cell lines (p = 0.046; p = 0.002 respectively). DNA fragmentation was also detected in B95-8 and Raji cell lines after EBV lytic cycle induction as compared to controls.ConclusionThe results of this study demonstrate the presence of increased combined oxidative modifications in lipids, proteins in B95-8 and Raji cells lines after EBV lytic cycle induction. These results suggest that lipid peroxidation, protein oxidation and DNA fragmentation are generally induced during EBV lytic cycle induction and probably contribute to the cytopathic effect of EBV.

Biomarkers of Neutrophil-Mediated Glutathione and Protein Oxidation in Tracheal Aspirates From Preterm Infants: Association With Bacterial Infection

Bronchopulmonary dysplasia is associated with neutrophil infiltration into the lungs and oxidative injury. However, the pathological importance of neutrophil oxidants is still not clear. Nosocomial pneumonia is also implicated, but the evidence is limited, in part because of the difficulty of distinguishing genuine infection from bacterial colonization. Good biomarkers of neutrophil oxidant activity and lung infection are needed. We tested whether glutathione sulfonamide, a product of glutathione oxidation by myeloperoxidase-derived hypochlorous acid (HOCl) and a potential new neutrophil oxidant biomarker, is detectable in endotracheal aspirates from ventilated preterm infants. As infectious organisms stimulate neutrophils to generate HOCl, we determined whether levels of HOCl-specific biomarkers were increased in samples that were bacterial culture positive. Glutathione sulfonamide was detected in 66 of 87 endotracheal aspirate samples. Levels correlated with myeloperoxidase activity and another HOCl-specific marker, chlorotyrosine. Median levels of glutathione sulfonamide (4-fold) and other biomarkers (2-fold) were significantly higher in culture positive aspirates. Staphylococcus epidermidis, a frequent colonizer, was associated with glutathione sulfonamide levels no different from those in negative samples. Glutathione sulfonamide showed good sensitivity and specificity for detecting bacterial growth and has promise for detecting lung infection.

Whey protein precludes lipid and protein oxidation and improves body weight gain in resistance-exercised rats

Resistance exercise such as weight-lifting (WL) increases oxidation products in plasma, but less is known regarding the effect of WL on oxidative damage to tissues. Dietary compounds are known to improve antioxidant defences. Whey protein (WP) is a source of protein in a variety of sport supplements and can enhance physical performance. To evaluate the effect of WL on biomarkers of lipid and protein oxidation, on liver antioxidants and on muscle growth in the absence or presence of WP in rats. Thirty-two male Fisher rats were randomly assigned to sedentary or exercise-trained groups and were fed with control or WP diets. The WL programme consisted of inducing the animals to perform sets of jumps with weights attached to the chest. After 8 weeks, arteriovenous blood samples, abdominal fat, liver and gastrocnemius muscle were collected for analysis. WP precludes WL-mediated increases in muscle protein carbonyl content and maintains low levels of TBARS in exercised and sedentary animals. WL reduced liver CAT activity, whereas WP increased hepatic glutathione content. In addition, WL plus WP generated higher body and muscle weight than exercise without WP. These data suggest that WP improves antioxidant defences, which contribute to the reduction of lipid and protein oxidation as well as body and muscle weight gain in resistance-exercised rats.

Plasma protein oxidation and its correlation with antioxidant potential during human aging.

Previous studies have indicated that the main molecular characteristic of aging is the progressive accumulation of oxidative damages in cellular macromolecules. Proteins are one of the main molecular targets of age-related oxidative stress, which have been observed during aging process in cellular systems. Reactive oxygen species (ROS) can lead to oxidation of amino acid side chains, formation of protein-protein cross-linkages, and oxidation of the peptide backbones. In the present study, we report the age-dependent oxidative alterations in biomarkers of plasma protein oxidation: protein carbonyls (PCO), advanced oxidation protein products (AOPPs) and plasma total thiol groups (T-SH) in the Indian population and also correlate these parameters with total plasma antioxidant potential. We show an age dependent decrease in T-SH levels and increase in PCO and AOPPs level. The alterations in the levels of these parameters correlated significantly with the total antioxidant capacity of the plasma. The levels of oxidized proteins in plasma provide an excellent biomarker of oxidative stress due to the relative long half-life of such oxidized proteins.

Plasma Protein Oxidation and Its Correlation with Antioxidant Potential During Human Aging

Previous studies have indicated that the main molecular characteristic of aging is the progressive accumulation of oxidative damages in cellular macromolecules. Proteins are one of the main molecular targets of age-related oxidative stress, which have been observed during aging process in cellular systems. Reactive oxygen species (ROS) can lead to oxidation of amino acid side chains, formation of protein-protein cross-linkages, and oxidation of the peptide backbones. In the present study, we report the age-dependent oxidative alterations in biomarkers of plasma protein oxidation: protein carbonyls (PCO), advanced oxidation protein products (AOPPs) and plasma total thiol groups (T-SH) in the Indian population and also correlate these parameters with total plasma antioxidant potential. We show an age dependent decrease in T-SH levels and increase in PCO and AOPPs level. The alterations in the levels of these parameters correlated significantly with the total antioxidant capacity of the plasma. The levels of oxidized proteins in plasma provide an excellent biomarker of oxidative stress due to the relative long half-life of such oxidized proteins.

Protein oxidation biomarkers in plasma of type 2 diabetic patients

Objectives To evaluate oxidative stress and the extent of oxidation of plasma proteins in type 2 diabetic patients. Design and methods Study was carried out on blood from 31 diabetic patients of both sexes (mean age = 58 ± 7; duration of diabetes 12 ± 5 years) and healthy age and sex matched normal subjects. Biomarkers of protein oxidation; plasma protein carbonyls (PCO), advanced oxidation protein products (AOPPs) and –SH group and free radical scavenging capacity of plasma was measured. Results PCO and AOPPS levels were significantly ( P < 0.005) higher in diabetic patients in comparison to healthy volunteers. Reduced free radical scavenging capacity ( P < 0.001) and –SH group ( P < 0.05) was observed in plasma of type 2 diabetic patients. Conclusions Our data suggest that diabetics are susceptible to protein oxidation. Oxidative modulation of proteins due to reduced radical scavenging activity of plasma patients may be one of the reasons of altered physiological processes in type 2 diabetic patients.