Markers Of Redox Status Research Articles

Antioxidant effect of zinc supplementation on both plasma and cellular red-ox status markers in a group of elderly Italian population.

The aim of this work was to evaluate the effect of long term supplementation with two moderate dose of Zn on plasma and cellular red-ox status markers in elderly volunteers. In a double blind study 108 healthy volunteers, aged 70-85 years, were enrolled. They were randomly divided in 3 groups of treatment, receiving placebo, 15 mg/day and 30 mg/day of Zn for 6 months. Red-ox status markers were assessed at baseline and after 6 months evaluating carotenoids, vitamin A and E in plasma; glutathione (GSH), thiol groups (RSH), malondialdehyde (MDA), percentage of haemolysis and methemoglobin in erythrocytes. Zn supplementation had no significant effects on red-ox status markers except for vitamin A levels (from 1.94±0.44 to 2.18±0.48 μM in volunteers receiving 15 mg of Zn and from 1.95±0.46 to 2.26±0.56 μM in volunteers receiving 30 mg of Zn), which increased proportionally to zinc dose. It appears that, differently from unhealthy populations, long-term supplementation with two moderate doses of Zn in a healthy elderly population, with an adequate Zn nutritive status and macro and micronutrients intakes in the range of normality, is an inefficient way to increase antioxidant defences.

Caffeine supplementation modulates oxidative stress markers in the liver of trained rats

AimsCaffeine has been widely used in sports competitions due to its ergogenic effects. Most of the studies regarding caffeine and exercise have focused on muscle and plasma adaptations, while the impact on the liver is scarcely described. The aim is to analyze the effects of caffeine and exercise training on oxidative stress markers and injury-related parameters in the liver. Main methodsRats were divided into sedentary/saline, sedentary/caffeine, exercise/saline, and exercise/caffeine groups. Exercise groups underwent 4weeks of swimming training, and caffeine (6mg/kg, p.o.) was supplemented throughout the training protocol. Injury-related liver parameters were assessed in plasma, while redox status and oxidative stress markers were measured on liver homogenates. Key findingsExercise training increased muscle citrate synthase activity in the muscle, while in caffeine decreased its activity in both sedentary and trained rats. Aspartate transaminase levels were increased after training, and caffeine intake suppressed this elevation (p<0.05). Caffeine also diminished alanine transaminase levels in both sedentary and exercised rats (p<0.05). Exercise training induced a significant increase on the activity of the enzymes superoxide dismutase and glutathione peroxidase, as an increase on thiobarbituric acid-reactive substances levels was also reached (p<0.05); caffeine intake blunted these alterations. Caffeine intake also suppressed liver catalase activity in both sedentary and exercise groups (p<0.05). SignificanceOur data suggest that caffeine modified the hepatic responses associated to exercise-induced oxidative stress without affecting the performance, exerting different actions according to the tissue. However, further studies are needed to better understand caffeine's role on liver under exercise training.

Omega-3 Fatty Acids Inhibit Tumor Growth in a Rat Model of Bladder Cancer

Omega-3 (ω-3) fatty acids have been tested on prevention and treatment of several cancer types, but the efficacy on “in vivo” bladder cancer has not been analyzed yet. This study aimed at evaluating the chemopreventive efficacy of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) mixture in an animal model of bladder cancer. Forty-four male Wistar rats were divided into 4 groups during a 20-week protocol: control; carcinogen—N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN); ω-3 (DHA + EPA); and ω-3 + BBN. BBN and ω-3 were given during the initial 8 weeks. At week 20 blood and bladder were collected and checked for the presence of urothelium lesions and tumors, markers of inflammation, proliferation, and redox status. Incidence of bladder carcinoma was, control (0%), ω-3 (0%), BBN (65%), and ω-3 + BBN (62.5%). The ω-3 + BBN group had no infiltrative tumors or carcinoma in situ, and tumor volume was significantly reduced compared to the BBN (0.9 ± 0.1 mm3 versus 112.5 ± 6.4 mm3). Also, it showed a reduced MDA/TAS ratio and BBN-induced serum CRP, TGF-β1, and CD31 were prevented. In conclusion, omega-3 fatty acids inhibit the development of premalignant and malignant lesions in a rat model of bladder cancer, which might be due to anti-inflammatory, antioxidant, anti-proliferative, and anti-angiogenic properties.

Metabolic and Glutathione Redox Markers Associated with Brain-Derived Neurotrophic Factor in Depressed African Men and Women: Evidence for Counterregulation?

Background: Major depression is associated with evidence for metabolic and redox imbalance and also with reports of lower serum levels of brain-derived neurotrophic factor (BDNF). However, the relationship between these factors has not been well studied. Methods: We studied the contribution of physiological risk factors to cardiometabolic health in 200 adult male and female black Africans, aged between 36 and 52 years, presenting with (n = 89) and without (n = 111) symptoms of depression. Specifically the association between serum BDNF and markers of basal metabolic and redox status in depressed versus nondepressed individuals were analyzed. Results: BDNF and markers of redox and metabolic status were not associated with the symptoms of depression. Waist circumference, a metabolic risk factor, was positively associated with BDNF and accounts for 49% of the variance in BDNF in depressed men. Reduced and oxidized glutathione were positively and negatively correlated with BDNF in depressed women, respectively, with glutathione redox status accounting for 36–42% of the variance in BDNF. Conclusion: Selected metabolic and redox factors explained gender-specific variances in serum BDNF levels in depressed African men and women. Our findings suggest that changes in redox and metabolic status may represent counterregulation by BDNF or alternatively that BDNF may mediate undesirable redox and metabolic changes that are associated with the development of a mood disorder.

Chemopreventive Efficacy of Atorvastatin against Nitrosamine-Induced Rat Bladder Cancer: Antioxidant, Anti-Proliferative and Anti-Inflammatory Properties

To investigate the anti-carcinogenic effects of Atorvastatin (Atorva) on a rat bladder carcinogenesis model with N-butyl-N-(4-hydroxibutil)nitrosamine (BBN), four male Wistar rat groups were studied: (1) Control: vehicle; (2) Atorva: 3 mg/kg bw/day; (3) Carcinogen: BBN (0.05%); (4) Preventive Atorva: 3 mg/kg bw/day Atorva + BBN. A two phase protocol was used, in which the drug and the carcinogen were given between week 1 and 8 and tumor development or chemoprevention were expressed between week 9 and 20, when the bladders were collected for macroscopic, histological and immunohistochemical (p53, ki67, CD31) evaluation. Serum was assessed for markers of inflammation, proliferation and redox status. The incidence of bladder carcinoma was: control 0/8 (0%); Atorva 0/8 (0%); BBN 13/20 (65%) and Atorva + BBN 1/8 (12.5%). The number and volume of tumors were significantly lower in the Atorva + BBN group, with a marked reduction in hyperplasia, dysplasia and carcinoma in situ lesions. An anti-proliferative, anti-inflammatory and antioxidant profile was also observed in the preventive Atorva group. p53 and ki67 immunostaining were significantly increased in the BBN-treated rats, which was prevented in the Atorva + BBN group. No differences were found for CD31 expression. In conclusion, Atorvastatin had a clear inhibitory effect on bladder cancer development, probably due to its antioxidant, anti-proliferative and anti-inflammatory properties.

Osteoblastic Responses to LPS, Glucose-oxidised LDL and Minocycline: Therapeutic Targets for Periodontal and Cardiometabolic Diseases

To study redox responses of cultured osteoblasts, mediated by bacterial lipopolysaccharide (LPS), glucose (G), glucose-oxidised low density lipoprotein (GLDL) and minocycline (M) using radiolabelled steroid markers of redox status and wound healing. The clinical relevance of this concept in periodontitis patients with cardiometabolic risk markers is addressed. A well differentiated osteoblastic cell-line was cultured in Eagle's MEM in confluent monolayer, in 24 well multiwell plates. Radiolabelled testosterone was used as the steroid substrate. Experiments were set up with controls in the absence of agents, optimal concentrations (previously determined) of G, GLDL, LPS, M, GLDL+LPS and the latter combined with M (n = 8). At the end of a 24h incubation period, the reaction was terminated and the medium analysed for yields of the steroid metabolite 5α-dihydrotestosterone (DHT), the redox marker relevant to wound healing, the weaker androgen 4-androstenedione (4-A) and the diols. Analysis entailed thin layer chromatography and radioisotope scanning. The yields of DHT showed 1.4-fold and 2.3-fold decreases in response to GLDL and LPS respectively and a 1.3-fold reduction in response to the combination, when compared with controls in the absence of agents. Minocycline stimulated the yield of DHT by 1.4-fold, and when combined with GLDL+LPS, the decreased yield was overcome and raised to 2-fold above the combination in response to the addition of minocycline (n = 8; p < 0.001), when compared with controls. The trends in the yields of 4-A and diols were inversely related to each other with increases and decreases over controls respectively, in keeping with enzymic pathways. Decreased yields of the oxidative stress marker DHT in response to LPS, G and GLDL were overcome in the presence of minocycline, which demonstrates its potential role as an adjunctive therapeutic agent in an environment of oxidative stress. These applications could be extrapolated to periodontal disease and co-existing cardiometabolic risk markers, in the context of its antiinflammatory and antioxidant actions relevant to healing. In this paper, recent patents relevant to adjunctive therapeutic management of periodontal disease co-existing with cardiometabolic risk markers are addressed. There have been significant advances in therapeutic interventions for overcoming oxidative stress-inducing mechanisms that are common to these disease entities.

Alkyl Hydroxytyrosyl Ethers Show Protective Effects against Oxidative Stress in HepG2 Cells

Alkyl hydroxytyrosyl ethers (methyl, ethyl, propyl, and butyl ethers) have been synthesized from hydroxytyrosol (HTy) in response to the increasing food industry demand of new lipophilic antioxidants. Having confirmed that these compounds reach portal blood partially unconjugated and thus are effectively absorbed, their potential antioxidant activity was evaluated in the human hepatocarcinoma cell line (HepG2). The effects of 0.5-10 μM alkyl hydroxytyrosyl ethers on HepG2 cell integrity and redox status were assessed as well as the protective effect against oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Cell viability (Crystal violet) and cell proliferation (BrdU assay) were measured as markers of cell integrity, concentration of reduced glutathione (GSH), generation of reactive oxygen species (ROS), and activity of antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GR) as markers of redox status and determination of malondialdehyde (MDA) as a marker of lipid peroxidation. Direct treatment of HepG2 with alkyl hydroxytyrosyl ethers induced slight changes in cellular intrinsic antioxidants status, reducing ROS generation and inducing changes in GPx and GR activities. Pretreatment of HepG2 cells with alkyl hydroxytyrosyl ethers counteracted cell damage induced by t-BOOH, partially after 2 h and completely after 20 h, by increasing GSH and decreasing ROS generation, MDA levels, and antioxidant enzyme (GPx and GR) activity. According to these results the alkyl hydroxytyrosyl ethers show clear protective effects against oxidative stress, related to their lipophilic nature, that are similar to or even higher than those of their precursor, HTy.

The effect of feeding a diet naturally contaminated with deoxynivalenol on production traits and selected biochemical indicators of broiler chickens

The effect of feeding a diet naturally contaminated with deoxynivalenol (DON) (0-21 days: 1.50 mg·kg-1; 22-39 days: 1.54 mg·kg-1) was studied in 40 broiler chickens. Birds were divided into two groups fed a control diet and a diet contaminated with DON (n = 20 in each). Feed intake was measured daily and individual live weight weekly; daily weight gain and feed to gain ratio were calculated. Five animals from each group were euthanized on days 21and 39 when blood (blood plasma and red blood cell haemolysates) and liver samples were collected. Concentration of triglyceride, uric acid and glucose and activities of ALT, AST and LDH were measured in blood plasma. Indicators of lipid peroxide and glutathione redox status, malondialdehyde and reduced glutathione concentration and glutathione-peroxidase activity were measured in blood plasma, red blood cell haemolysates and liver homogenates. The low dose of DON did not cause difference in the production traits, but caused significantly lower concentration of uric acid and glucose, and significantly higher concentration of triglyceride in blood plasma on day 21. Enzyme activities in blood plasma did not differ significantly between the treatment groups. Among the markers of lipid peroxide and glutathione redox status, malondialdehyde content was significantly higher in liver homogenate on day 21 in the group fed with DON contaminated diet, but reduced glutathione content and glutathione peroxidase activity did not differ significantly between the treatment groups. The results showed that diet contaminated even with a low content of deoxynivalenol caused alterations in selected biochemical indicators of blood and liver of broiler chicken.

Inhibition of bladder tumour growth by sirolimus in an experimental carcinogenesis model

To investigate the anticarcinogenic effects of sirolimus 2 mg/kg/day on a rat model of urinary bladder carcinogenesis induced with N-butyl-N(4-hydroxybutyl)nitrosamine (BBN). Thirty-six male Wistar rats were divided into four groups: 1, a control group (eight), given tap water only; 2, a sirolimus control group (eight), given 2 mg/kg/day; 3, a carcinogen (BBN) group (12) exposed to 0.05% BBN; 4, a treatment group (sirolimus/BBN; eight) given 2 mg/kg/day + 0.05% BBN. In the tumour-induction phase, from week 1 to week 8, rats from groups 3 and 4 received BBN ad libitum in drinking water. In the treatment phase, from week 8 to week 20, rats from groups 2 and 4 received sirolimus 2 mg/kg/day by an oesophageal cannula. At week 20 the rats were killed humanely, and the number and size of tumours recorded. The bladders were collected for histological, immunohistochemical and gene expression evaluation. Blood was collected for the determination of several serum proliferative and inflammatory markers. Lipid peroxidation, through serum malondialdehyde (MDA) content, and total antioxidant status (TAS) were also evaluated. Sirolimus caused a marked inhibition of bladder tumour growth. When compared with group 3, group 4 had a reduced proportion of rats with tumour (three of eight vs eight of 12), and significantly fewer tumours per rat, with a mean (sd) of 1.00 (0.0) vs 1.88 (0.35), and tumour volume per tumour, of 0.30 (0.11) vs 66.1 (48.9) mm³, with less aggressive histological changes, i.e. a marked reduction in hyperplasia (four of eight vs 12/12), high-grade dysplasia (four of eight vs 11/12) and urothelial tumour. Rats in group 4 had no infiltrative bladder cancers and had a lower incidence of high-grade tumours than rats in group 3. The rats in group 4 had decreased serum levels of transforming growth factor-β1, higher levels of tumour necrosis factor-α, and higher levels of serum TAS and a better serum MDA/TAS ratio, a marker of more favourable redox status. Furthermore, the down-regulation of bladder caspase 3 gene expression and the increased Ki67 immunostaining in group 3 were significantly attenuated in group 4. Sirolimus given as an oral agent, 2 mg/kg/day, significantly inhibited rat bladder carcinogenesis. Sirolimus reduced the number and volume of tumours and induced a less aggressive histological behaviour. This might be due to antiproliferative and antioxidant properties, as well as to the restoration of apoptotic pathways.

Coenzyme Q10 in human blood: Native levels and determinants of oxidation during processing and storage

Coenzyme Q10 (Q10) is present in the circulation mainly in its reduced form (ubiquinol-10; UL10), but oxidizes quickly ex vivo to ubiquinone-10 (UN10). Therefore, native UL10:UN10 ratios, used as markers of redox status and disease risk, are difficult to measure. We established an RP-(U)HPLC method with coulometric detection to measure natively circulating UL10 and UN10 concentrations by adding a ubiquinol/ubiquinone mixture as an internal standard immediately after plasma preparation. This allowed adjustment for unavoidable artificial UL10 oxidation as well as for total losses (or gains) of analytes during sample storage, processing, and analysis because the internal standards exactly paralleled the chemical behavior of Q10. This technique applied to blood ( n = 13) revealed Q10 levels of 680–3300 nM with a mean UL10:UN10 ratio of 95:5, which was inversely associated with total Q10 ( r = − 0.69; p = 0.004). The oxidation of UL10 to UN10 was equimolar, increased by O 2, and decreased by lower temperatures or various degassing methods. Although UL10 was stable in blood or when pure in organic solvents at 22 °C, its oxidation was catalyzed dose dependently by α-tocopherol and butylated hydroxytoluene, particularly when present in combination. Key structural features for the catalytic pro-oxidant properties of phenolic antioxidants included two substituents vicinal to the phenolic hydroxyl group.

Effect of Recombinant Human Erythropoietin in a Rat Model of Moderate Chronic Renal Failure - Focus on Inflammation, Oxidative Stress and Function/Renoprotection

Background/Aims: Chronic renal failure (CRF) patients develop anaemia, thus promoting cardiovascular complications, which seems to be favoured by the low kidney erythropoietin (EPO) production. The renal insufficiency degree might determine the moment to start recombinant human EPO (rhEPO) therapy. It has been attributed important non-hematopoietic effects to rhEPO, which might underlie cardio and renoprotection. This work aimed to evaluate the effect of rhEPO in a rat model of moderate CRF, focusing on inflammation, oxidative stress and function/renoprotection. Methods: Four groups (n=7) of male Wistar rats were evaluated during a 15 week follow-up period: control (without treatment); rhEPO (50 IU/Kg/wk Recormon ® ); CRF and CRF+rhEPO. Blood samples were collected at the beginning and 3, 9 and 12 weeks afternephrectomy, in order to evaluate: renal function, haematological parameters, iron metabolism and serum proliferative (TGF- 1), inflammatory (TNF- , CRP, IL-2 and IL-1 ) and redox status (MDA, TAS and 3-NT) markers. Kidney gene expression of Il2, Vegf, Nos2 and Nos3 were assessed by real-time PCR. Blood pressure, heart rate and tissues trophy indexes were also estimated. Results: Our data are consistent with a sustained moderate degree of CRF with development of moderate and corrected anaemia and hypertension. The remnant kidney showed a proliferative profile, with increased mass (hypertrophism), upregulated tissue Vegf gene expression, accompanied by increased levels of serum TGF- 1. Serum 3-NT was augmented, suggesting oxidative stress, which was accompanied by a trend to higher kidney Nos gene expression of both isoforms. rhEPO treatment was able to partially attenuate renal function markers, totally correct anaemia, also demonstrating a proliferative and antioxidant action, suggesting renoprotection. Conclusion: This study suggests that rhEPO therapy might be recommended in moderate CRF stages in order to efficiently correct not only the anaemia but also the underlying deleterious mechanisms, due to a proliferative and antioxidant action on the remnant kidney.

Characterization of a Rat Model of Moderate Chronic Renal Failure—Focus on Hematological, Biochemical, and Cardio-Renal Profiles

The pathophysiological modifications underlying chronic renal failure seems to be dependent on the insufficiency degree, which will determine the moment to start therapy. As there is yet limited information about animal models of moderate chronic renal failure, we intended to perform a complete characterization of the hematological and cardio-renal alterations induced by partial nephrectomy. Blood samples from control and chronic renal failure rats were collected at 0, 3, 9, and 15 weeks in order to evaluate renal function, hematological parameters, iron metabolism, blood lipids, peripheral sympathetic nervous system, and inflammatory and redox status markers. BP, tissues trophy indexes, and kidney histomorphology were also assessed. Our data are consistent with a sustained moderate degree of chronic renal failure with a quickly compensated modest anaemia, though presenting iron metabolism disturbances. Despite the reasonable degree of functionality of the remnant kidney, as suggested by the anaemia correction and by the kidney hypertrophy and moderate lesions, several important cardiovascular modifications were developed. Our model presented hypertension, dyslipidemia, erythropoietic disturbances, sympathetic activation, and oxidative stress. This model might be a good tool to study the cellular/molecular mechanisms underlying moderate stages of chronic renal failure and to evaluate the therapeutic efficacy for prevention and treatment/correction of cardio-renal anaemia syndromes and complications in early stages.

Inflammatory and redox status of ponies with a history of pasture-associated laminitis

Inflammatory and redox signals could render lamellar tissue susceptible to damage and contribute to higher risk for laminitis in obese or insulin resistant ponies just as these factors contribute to health risks in humans with metabolic syndrome. This study evaluated circulating markers of inflammatory and redox status in ponies that had a history of recurrent bouts of pasture-associated laminitis (PL, n = 42) or had never developed clinical laminitis (NL, n = 34) under the current management conditions. There were no differences ( P > 0.05) between PL and NL ponies for markers of antioxidant function (glutathione, glutathione peroxidase, superoxide dismutase) or increased oxidative pressure (malondialdehyde, apoptosis, 3-nitrotyrosine). Inflammatory status, as indicated by fibrinogen concentration, was also not different between pony groups ( P = 0.84). However, PL ponies had higher ( P < 0.001) plasma concentrations of the pro-inflammatory cytokine TNF-α than NL ponies. This suggests that a predisposition to laminitis is associated with increased circulating inflammatory cytokines. TNF-α could also represent a contributing factor to increased insulin resistance observed in laminitis prone ponies. These results provide new insight into potential mechanisms and risk factors underlying laminitis.

Preferential response of glutathione-related enzymes to folate-dependent changes in the redox state of rat liver

Oxidative stress likely constitutes an important contributing factor in the onset of degenerative diseases associated with folate deficiency. Direct, as well as homocysteine-linked, antioxidant properties of folate could explain its preventive effect on these pathologies. Our study aimed at determining the changes in the redox status of adult rats as a function of folate intake. Adult male rats were pair-fed for 4 weeks with a semi-synthetic diet containing 0, 0.5, 1.5, 8 or 20 mg of folic acid/kg. Folate and homocysteine concentrations, redox status markers and antioxidant enzyme activities were measured in the plasma and/or liver of the rats. A principal component analysis of the overall data was performed to draw a general scheme of the changes observed between the conditions. Folate deficiency caused increased homocysteinemia and features of oxidative stress including reduced plasma antioxidant capacity together with increased lipid peroxidation in liver and heart. This was associated with an increase in the specific activity of several enzymes involved in liver glutathione metabolism (glutathione peroxidase, glutathione reductase and glutathione S-transferase), suggesting an adaptive tissue response to the oxidative stress induced by folate deficiency. In contrast, no such variation was observed for hepatic superoxide dismutase and catalase. Despite no changes in hepatic levels of total glutathione, our findings indicate that glutathione-dependent antioxidant pathways could be particularly involved in the compensatory mechanism committed by liver to counteract the oxidative stress induced by folate deficiency. They also suggest that folate supplementation may not be associated with a better antioxidant protection of rats.

Quantification of Cysteine Oxidation in Human Estrogen Receptor by Mass Spectrometry

Redox-dependent modifications of sulfhydryl groups within the two Cys4 zinc fingers of the estrogen receptor DNA-binding domain (ER-DBD) result in structural damage and loss of ER DNA-binding function, which parallels the situation observed in many ER-positive breast cancers. Quantitation of the redox status of cysteinyl thiols within ER-DBD employed cysteine-specific oxidants to induce varying degrees of oxidation in recombinant ER, followed by differential alkylation with the stable isotopic labeling reagents [12C2]-iodoacetic acid and [13C2]-bromoacetic acid. Subsequent proteolysis with LysC/Asp-N generated diagnostic peptides of which the C-terminal peptide of the second zinc finger is most strongly detected by mass spectrometry (MS) and serves as a suitable marker of ER-DBD redox status. Data were collected from two different MALDI-MS instruments: a time-of-flight and a linear ion trap (vMALDI-LIT). An analogous but larger synthetic peptide treated with three isotopic variants of the alkylating reagent modeled isotopic overlaps that might complicate the relative quantitation of cysteine oxidation. Despite the isotopic overlaps, excellent relative quantitation was achieved from MS data obtained from both instruments. This was also true of tandem MS/MS data from the vMALDI-LIT, which should facilitate selected reaction monitoring. Relative quantitation by MS also closely matched data from immunochemical methods.

Effect of the olive oil phenol hydroxytyrosol on human hepatoma HepG2 cells

Scientific evidence suggests that olive oil's beneficial effects are related to the high level of antioxidants, including phenolic compounds such as hydroxytyrosol. In vivo studies have shown that olive oil HTy is bioavailable and its biological activities, similar to those reported for other natural antioxidants such as quercetin, include prevention of LDL oxidation. Previous studies from our laboratory have shown that HTy and other phenolics in olive oil are absorbed and metabolized by cultured human hepatoma HepG2 cells where glucuronidated and methylated conjugates were the main derivatives formed, resembling the metabolic profile of olive oil phenols observed in human plasma and urine. The effect of olive oil phenol (HTy) on cell viability and redox status of cultured HepG2 cells, and the protective effect of HTy against an oxidative stress induced by tertbutylhydroperoxide (t-BOOH) were investigated. Lactate dehydrogenase activity as marker for cell integrity, concentration of reduced glutathione (GSH), generation of reactive oxygen species (ROS) and activity of the antioxidant enzyme glutathione peroxidase (GPx) as markers of redox status and determination of malondialdehyde (MDA) as marker of lipid peroxidation were measured. No changes in cell integrity or intrinsic antioxidant status resulted from a direct treatment with 10-40 microM HTy. Pre-treatment of HepG2 with 10-40 microM HTy for 2 or 20 h completely prevented cell damage as well as the decrease of reduced glutathione and increase of malondialdehyde evoked by t-BOOH in HepG2 cells. Reactive oxygen species generation and the significant increase of glutathione peroxidase activity induced by t-BOOH were greatly reduced when cells were pretreated with HTy. The results clearly show that treatment of HepG2 cells with the olive oil phenolic HTy may positively affect their antioxidant defense system, favoring cell integrity and resistance to cope with a stressful situation.

The evaluation of altered redox status in plasma and mitochondria of acute and chronic diabetic rats

Objectives An increase in plasma oxidative stress and decreased mitochondrial lipid hydroperoxides may contribute to the imbalance in the redox status between intramitochondrial and extramitochondrial milieu in chronic experimental diabetic rats. Design and methods To determine the effect of hyperglycemia in promoting redox imbalance, we determined lipid hydroperoxides (LHP), protein carbonyl (PCO), total antioxidant activity (ferric reducing/antioxidant power; FRAP) and albumin as markers of redox status of plasma, and mitochondrial lipid hydroperoxide levels as a marker of lipid peroxidation in liver, pancreas and kidney tissue of acute and chronic diabetic male Sprague–Dawley rats and their controls. The levels of the studied markers were determined by colorimetric methods. Results Plasma and mitochondrial oxidative stress parameter levels of acute diabetic rats were not significantly different from their controls. Plasma LHP and PCO levels of chronic diabetic rats were increased significantly as compared to those of both acute diabetic rats and the controls. Plasma FRAP levels of chronic diabetic animals were decreased significantly as compared to those of the controls. On the other hand, LHP levels in liver, pancreas and kidney mitochondria of chronic diabetic rats were decreased significantly as compared to those of both acute diabetic rats and the controls. We observed a negative correlation between LHP levels in liver mitochondria of chronic diabetic rats, and PCO and fructosamine levels in plasma of chronic diabetic rats were correlated. LHP levels in the pancreatic mitochondria of chronic diabetic rats and plasma oxidative stress parameters of chronic diabetic rats were not significantly correlated. LHP levels in kidney mitochondria of chronic diabetic rats were significantly correlated with serum albumin. There was no correlation between LHP levels in kidney mitochondria and other plasma oxidative stress parameters in chronic diabetic rats. Conclusions Our data suggest that redox imbalance between plasma and liver mitochondria might become a major threat to chronic diabetic rats.

Tu-P10:420 Time-course of redox-status and inflammatory markers in acute coronary syndromes

Tu-P10:420 Time-course of redox-status and inflammatory markers in acute coronary syndromes

Mouse HSF1 Disruption Perturbs Redox State and Increases Mitochondrial Oxidative Stress in Kidney

Increased synthesis of heat shock proteins (Hsps), mainly regulated by heat shock factor 1 (Hsf1), protects the heart against oxidative stress under pathophysiological conditions such as ischemia/reperfusion. To investigate whether Hsps might exert a similar protective effect under physiological conditions in the kidney, we first evaluated the HSF1-dependent expression of several Hsps, including Hsp25, alphaB-crystallin (alphaBC), Hsp70, and Hsp90. Unlike either alphaBC or Hsp70, protein expression of Hsp25 and Hsp90 was decreased 26% and 50%, respectively, in Hsf1 knockout compared with the wild-type mice. The effects of Hsp down-regulation on renal cellular redox status are presently unknown. Indeed, HSF1 deficiency caused a 37% decrease in renal cellular GSH/GSSG ratio, a marker of redox status, and a 40% increase in the rate of mitochondrial superoxide generation in Hsf1 knockout compared with wild-type mice. HSF1 disruption also increased mitochondrial permeability transition pore opening and induced greater mitochondrial membrane potential change (48% increase versus wild type). Thus, the present study demonstrates that Hsf1-dependent transcription of selective Hsps is required for normal renal homeostasis, which protects renal cells against oxidative stress under physiological conditions. The source of mitochondrial superoxide generation is discussed.

Effect of High Intakes of Fruit and Vegetables on Redox Status in Type 2 Onset Diabetes: A Pilot Study

Evidence has accumulated indicating that oxidative stress may play a key role in the etiology of diabetic complications and the protective effects of antioxidant nutrients are a topic of intense research. The purpose of this study was both to obtain preliminary data on the effect of a diet high in fruit and vegetables on metabolic control and the oxidative status of patients with type 2 onset diabetes, and to identify the most useful biochemical parameters for future research. At the beginning of the study all subjects were asked to follow their usual diet and keep a seven-day food diary. Diabetic patients then received a dietary treatment designed to ensure a daily intake of 700-1000 g of fruit and vegetables; no dietary advice was given to controls. Dietary antioxidants, redox status markers, and parameters of metabolic control were measured in plasma and erythrocytes before and after the diet. Before following the diet, diabetic patients had lower levels of ascorbic acid, beta-carotene, and alpha-tocopherol/cholesterol ratio than controls. After the diet these parameters increased and there was also a reduction in total antioxidant capacity, uric acid, and malondialdehyde and a rise in reduced glutathione accompanied by a reduction in body mass index and cholesterol. In conclusion, a high consumption of fruit and vegetables by diabetic patients not receiving pharmacological treatment, seems to produce an improvement in some redox status parameters.