Serum Oxidative Stress Biomarkers Research Articles

Serum lipoprotein profile and oxidative stress biomarkers in Wistar rats fed drinking water containing iron and copper

The aim of the research was to estimate the effect of different doses and combinations of iron and copper consumption with drinking water on lipid profile and oxidative stress biomarkers in albino Wistar rats serum. Rats were given drinking water containing 3 mg L �1 and 6 mg L �1 iron; copper 4.88 and 9.76 mg L �1 ; a mixture of 3 mg L �1 iron and 4.88 mg L �1 copper. Control group obtained pure drinking water. Total cholesterol, lipoprotein spectrum and markers of lipid and protein oxidation were analyzed. It has been seen that administration of iron in concentration of 6 mg L �1 induces lipid peroxidation and protein oxidation, while copper given in the maximal doses leads only to protein oxidation. Free radical oxidation in rats obtaining combination of iron and copper with drinking water was more expressed than in case of administration of single metals in the same doses. Consumption of maximal doses of isolated metals leads to more expressed atherogenic changes, while combination of both metals in lower doses did not affect serum lipoprotein significantly. The data obtained show that chemical interaction of iron and copper in the organism has an additive effect on some vital parameters in comparison to isolated metal administration.

Ambience-associated variation in serum biomarkers of oxidative stress in donkeys of arid tracts in India

An investigation was carried out in donkeys to discover serum biomarkers of oxidative stress during moderate and extremely hot conditions. Serum biomarkers included vitamin A, vitamin C, vitamin E, glutathione, catalase, superoxide dismutase, monoamine oxidase, glutathione reductase, xanthine oxidase, oxidase and peroxidase. These findings were compared with those obtained during the moderate conditions that served as a control. Serum vitamin A, vitamin C, vitamin E and glutathione activity decreased significantly during hot conditions, while serum catalase, superoxide dismutase, monoamine oxidase, glutathione reductase, xanthine oxidase, oxidase and peroxidase activities all increased significantly. It was concluded that hot ambient stress induced marked changes in the levels of biomarkers in the serum of donkeys, indicating oxidative stress.

Chronic administration of iron and copper potentiates adipogenic effect of high fat diet in Wistar rats

The primary objective of this research project is explore a possible adipogenic effect of iron and/or copper in albino Wistar rats kept on standard (STD) and high-fat (HFD) diets. The female Wistar rats in the study were divided into eight experimental groups (n = 6). Rats maintained on STD and HFD received 3 mg/l FeSO₄∙7H₂O, 4.88 mg/l CuSO₄ and a combination of 1.5 mg/l FeSO₄∙7H₂O and 2.44 mg/l CuSO₄ with drinking water. Control groups were kept on STD and HFD and received pure water without metal salts. Consumption of iron and copper in the groups of rats maintained on an STD did not produce a significant increase in weight, adipose tissue content or body mass index. However, the adipocyte size and infiltration were increased in the adipose tissue of STD-fed rats receiving a mixture of iron and copper with drinking water. The rats fed iron and copper and, especially, their combination on a HFD background had a significantly higher weight gain, adipose tissue content, morphometric parameters values and adipocyte size compared to STD- and HFD-fed controls. Iron and copper consumption produced their accumulation in the rats' adipose tissue. Moreover, the studied metals reduced adipose tissue concentration of chromium and vanadium. The lipoprotein profile and serum oxidative stress biomarkers were affected in the rats receiving the metals and STD. Hyperglycemia was observed in the rats receiving the studied metals on HFD-background. Based on the analysis of the test subjects, the study suggests that iron and copper administration, especially combined, may potentiate adipogenic effect of HFD.

Comparison of serum ferritin and oxidative stress biomarkers between Japanese workers with and without metabolic syndrome

Metabolic syndrome (MS) is closely associated to life-style and is characterized by central obesity causing severe diseases such as diabetes mellitus (DM) or atherosclerosis. This study investigates the role of oxidative stress and inflammation in MS. Total of 685 workers stratified by gender (293 men and 392 women) with a mean age of 41.2 ± 10.4 in different offices in a city in Japan. Fasting blood and urine tests for MS, oxidative and/or inflammatory biomarker analysis and blood pressure (BP) measurement were performed. MS was defined on the basis of the Japanese criterion. Serum ferritin and urinary hydrogen peroxide (H2O2) levels were significantly higher in subjects with MS than those without. Ferritin was positively correlated with 8-hydroxy-2'-deoxyguanosine (8-OHdG) in all subjects and it was negatively correlated with 8-isoprostane and H2O2 in men. In addition, there was a significant positive correlation between ferritin and homeostasis model assessment (HOMA-R) in men. By using multiple regression analysis, ferritin was closely correlated with HOMA-R, γ-GT, 8-OHdG, smoking value and amount of alcohol ingestion in men, and it was correlated with 8-OHdG, γ-GT, HOMA-R in women under 50 years old. Ferritin is a useful marker of MS including insulin resistance, reflecting the importance of oxidative stress as a cause of MS, especially in men.

Assessment of Oxidative Stress in Peste des petits ruminants (Ovine rinderpest) Affected Goats

The aim of the present investigation was to evaluate oxidative stress in goats affected with peste des petits ruminants (PPR). The experiment was designed to collect blood samples from PPR affected as well as healthy goats during a series of PPR outbreaks which occurred during February to April 2012 in different districts of Rajasthan state (India). Out of total 202 goats of various age groups and of both the sexes, 155 goats were PPR affected and 47 were healthy. Oxidative stress was evaluated by determining various serum biomarkers viz . vitamin A, vitamin C, vitamin E, glutathione, catalase, superoxide dismutase, glutathione reductase and xanthine oxidase, the mean values of which were 1.71±0.09 µmol L -1 , 13.02±0.14 µmol L -1 , 2.22±0.09 µmol L -1 , 3.03±0.07 µmol L -1 , 135.12±8.10 kU L -1 , 289.13±8.00 kU L -1 , 6.11± 0.06 kU L -1 and 98.12±3.12 mU L - 1, respectively. Each parameter analysis of variance showed highly significant effect (P=0.0001) of health status and age category. Further interaction between health status and age category was also highly significant (P=0.0001) for each parameter studied. The results indicated that vitamins A, C, E and glutathione levels depressed by 18.95%, 38.67%, 47.64%, and 47.39%, respectively and the serum catalase, superoxide dismutase, glutathione reductase and xanthine oxidase activities increased by 90.79%, 75.11%, 90.34%, and 44.06%, respectively in affected animals as compared to that in healthy ones. On the basis of the altered levels of serum biomarkers of oxidative stress it was concluded that the animals affected with PPR developed oxidative stress.

Serum and follicular oxidative stress biomarkers levels and response to controlled ovarian hyperstimulation (COH) in IVF cycles

Oxidative stress (OS) may be involved in the etiology of defective oocyte maturation and embryo development. However, the potential impact of OS in ovarian response to controlled ovarian hyperstimulation (COH) for IVF cycles has not been evaluated. Thus, the aim of the present study was to investigate the relationship between OS biomarkers levels in the serum and follicular fluid (FF) and the patterns of response to COH in IVF cycles.

Apple peel flavonoid- and triterpene-enriched extracts differentially affect cholesterol homeostasis in hamsters

Flavonoids and triterpenes are two major groups of bioactive compounds in apple peels. This study determined whether flavonoid-rich (FAE) and triterpene-rich (TAE) apple peel extracts affect cholesterol metabolism in diet-induced hypercholesterolemic male Golden Syrian hamsters. Two groups of hamsters were supplemented with 50mg bioactives/kg/d of FAE or TAE and the third group was the atherogenic control (AC). After 28days, FAE reduced (p<0.05) serum total cholesterol (TC) and non-high density lipoprotein cholesterol (non-HDL) compared to AC. In contrast, TAE increased (p<0.05) serum TC. Extracts had no effect on serum triacylglycerol and HDL. Both FAE and TAE increased (p<0.05) cholesterol absorption without any effect on cholesterol biosynthesis. Liver TC, free cholesterol, triacylglycerol, serum and liver oxidative stress biomarkers were not altered by any extract. FAE and TAE differentially affected cholesterol metabolism where FAE effectively lowered serum cholesterol, with the underlying mechanism awaiting further investigation.

Cellular and plasma oxidative stress biomarkers are raised in adults with bronchiectasis

Oxidative stress is believed to play an important role in the pathophysiology of bronchiectasis. The aims of this study were to evaluate the oxidative stress status in bronchiectasis patients. This cross-sectional study included 90 clinically stable adults with bronchiectasis of any aetiology (36 with cystic fibrosis [CF] and 54 without CF) plus 50 healthy controls. Plasma and serum oxidative stress biomarkers were measured using commercial kits. Cellular oxidative stress biomarkers in white blood cells (mitochondrial membrane potential, intracellular glutathione, superoxide anion and hydrogen peroxide) were analyzed by flow cytometry. Compared with the control group, the catalase activity and lipid peroxidation (TBARs and 8-isoprostanes) were significantly increased in the patient group and the total antioxidant capacity and the activity of superoxide dismutase were decreased. Intracellular superoxide anion and hydrogen peroxide were significantly elevated in the patients versus the controls in total leukocytes, lymphocytes, monocytes and neutrophils. Compared to the controls, the mitochondrial membrane potential was significantly lower in neutrophils and intracellular glutathione in monocytes. No significant differences were observed between CF and non-CF bronchiectasis patients in the oxidative stress biomarkers studied. Biomarkers of oxidative stress, both in plasma and intracellular were raised in patients with bronchiectasis compared with controls. No differences were seen in the CF patients compared with the others.

Abstract CN06-02: Phase IB randomized, double-blinded, placebo-controlled, dose escalation study of Polyphenon E in women with a history of hormone receptor-negative breast cancer

Abstract Background: Priorities in breast cancer chemoprevention include developing safe and tolerable agents for potential chronic use that are effective against hormone receptor (HR)-negative breast cancer and validating intermediate biomarkers which correlate with breast cancer risk. Various epidemiologic studies have demonstrated an inverse association between green tea consumption and breast cancer risk. The primary polyphenol of green tea, epigallocatechin gallate (EGCG), is a potent antioxidant that acts on multiple stages of carcinogenesis. The primary objective of this phase IB trial was to demonstrate the safety of using an oral green tea extract, Polyphenon E (Poly E), over a 6-month period in patients with a history of HR-negative breast cancer. Secondary exploratory objectives were to investigate the dose-related biologic effects of Poly E on breast tissue, radiographic, serum and urine-based biomarkers. Methods: Forty women with stage I-III HR-negative breast cancer who completed adjuvant treatment were randomized to oral Poly E: (1) 400mg, (2) 600mg, or (3) 800mg (2–4 capsules) bid or matching placebo for 6 months. The primary endpoint of this dose escalation study was to determine the maximum tolerated dose (MTD) of Poly E in this patient population, defined as the dose that causes 25% dose limiting toxicity (DLT, grade 2 or higher). Assignment to dose level was based upon an adaptive clinical trial design called the time-to-event continual reassessment method, such that more participants were assigned to the MTD. Safety was assessed by monitoring clinical and laboratory parameters during monthly visits. At baseline and 6 months, a mammogram and random core biopsy of the contralateral breast and serial blood and urine collections were obtained for biomarker analyses. Secondary exploratory endpoints included breast tissue-based biomarkers (Ki-67, ER), mammographic density, serum hormone metabolites (estradiol, testosterone, IGF-I, IGFBP-3, SHBG), inflammatory and oxidative stress biomarkers (serum CRP, urine PGE-M, 8-OHdG, isoprostane). Results: From July 2007 to Sept 2009, 40 women were enrolled from 4 sites. Baseline characteristics included median age: 55 (39–65); pre/postmenopausal: 10/30; White/Hispanic/Black/Asian: 23/9/7/1; stage I/II/III: 16/15/9; median time since diagnosis: 33 months (10–170). Eighteen participants were each assigned to dose levels 1 and 2, four participants to dose level 3. There was 1 DLT at dose level 1 (grade 3 rectal bleeding), 3 DLTs at dose level 2 (grade 2 weight gain and indigestion, grade 3 insomnia), and 1 DLT at dose level 3 (grade 3 liver function abnormality). As a result, 600mg bid was found to be the MTD for Poly E. Biomarker analyses are currently ongoing. Conclusions: Using a novel clinical trial design for phase I testing which evaluates long-term toxicity, we determined the MTD for Poly E that will serve as the upper safety limit in future breast cancer chemoprevention trials. We also obtained preliminary data on the biological effects of Poly E on biomarkers of breast cancer risk, which can elucidate potential mechanisms of action and possibly serve as surrogate endpoints in future clinical efficacy trials. Citation Information: Cancer Prev Res 2011;4(10 Suppl):CN06-02.

The effects of Bifidobacteria on the lipid profile and oxidative stress biomarkers of male rats fed thermally oxidized soybean oil

Over the years, there has been concern about the changes taking place in heated oils and the effects on individuals consuming them. The present study investigated the effects of a diet containing thermally oxidized soybean oil (TO) or TO supplemented with probiotic Bifidobacteria (TO+Pro) on the serum lipid profile and oxidative stress biomarkers of male rats. The data showed several indicators of oil deterioration after thermal processing, including high levels of % free fatty acid (FFA; 15-fold), acid value (AV; 14-fold), peroxide value (8-fold), p-anisidine value (AnV; 39-fold), total oxidation value (TOTOX; 19-fold), thiobarbituric acid–reactive substances (TBARS) value (8.5-fold), and trans-FA (TFA) isomers (2.5-fold) compared to the control. The rats that were fed a diet containing TO showed a significant (p < 0.05) decrease in body weight gain, food efficiency values, and liver weight. Furthermore, the total cholesterol and low-density lipoprotein (LDL) levels were increased, while the high-density lipoprotein (HDL) level was decreased in blood serum samples. High levels of TBARS, superoxide dismutase (SOD), and glutathione reductase (GR) activities were also detected in the livers, kidneys, testes, and brains of rats. Interestingly, a diet containing TO+Pro restored all biological parameters to their control values. The present data suggested that Bifidobacteria may ameliorate the serum lipid profile and oxidative stress biomarkers that are generated in animals that are fed a TO diet.

Antioxidant Potential of Momordica Charantia in Ammonium Chloride-Induced Hyperammonemic Rats.

The present study was aimed to investigate the antioxidant potential of Momordica charantia fruit extract (MCE) in ammonium chloride-induced (AC) hyperammonemic rats. Experimental hyperammonemia was induced in adult male Wistar rats (180–200 g) by intraperitoneal injections of ammonium chloride (100 mg kg−1 body weight) thrice a week. The effect of oral administration (thrice a week for 8 consecutive weeks) of MCE (300 mg kg−1 body weight) on blood ammonia, plasma urea, serum liver marker enzymes and oxidative stress biomarkers in normal and experimental animals was analyzed. Hyperammonemic rats showed a significant increase in the activities of thiobarbituric acid reactive substances, hydroperoxides and liver markers (alanine transaminase, aspartate transaminase and alkaline phosphatase), and the levels of glutathione peroxidase, superoxide dismutase, catalase and reduced glutathione were decreased in the liver and brain tissues. Treatment with MCE normalized the above-mentioned changes in hyperammonemic rats by reversing the oxidant-antioxidant imbalance during AC-induced hyperammonemia, and offered protection against hyperammonemia. Our results indicate that MCE exerting the antioxidant potentials and maintaining the cellular integrity of the liver tissue could offer protection against AC-induced hyperammonemia. However, the exact underlying mechanism is yet to be investigated, and examination of the efficacy of the active constituents of the M. charantia on hyperammonemia is desirable.

Human Atrial Natriuretic Peptide Attenuates Renal Ischemia-Reperfusion Injury

Acute kidney injury (AKI) is common in the intensive care unit, and one of its primary causes is renal ischemia-reperfusion (I/R) injury. Human atrial natriuretic peptide (hANP) exerts various pharmacologic effects, including renal protection. In the present study, we evaluated the renal protective effect of hANP in a rat model of renal I/R. Male Wistar rats were divided into three groups that received the following treatments: induction of renal I/R (I/R group); continuous intravenous injection of hANP followed 30 min later by induction of renal I/R (hANP+I/R group); and sham treatment (control group). Rats were sacrificed after 60 min of ischemia and 24 h of reperfusion or sham treatment. To evaluate the renal protective effects if hANP, serum blood urea nitrogen (BUN) and creatinine (Cre) concentrations were determined, kidneys were histologically assessed, and serum biomarkers of oxidative stress were evaluated. In addition, antimycin A (AMA)-stimulated RAW264.7 cells were treated with hANP to assess its antioxidant effects. Serum BUN and Cre levels were elevated in the I/R group; however, these increases were significantly inhibited in the hANP + I/R group. Similarly, kidney tissue damage observed in the I/R group was attenuated in the hANP + I/R group. In vitro, AMA-stimulated cells treated with hANP showed reduced reactive oxygen species activity compared to cells treated with AMA alone. Our findings indicate that hANP may be effective in the treatment of various types of I/R injuries.

Serum Biological Antioxidant Potential Predicts the Prognosis of Hemodialysis Patients

Background: It is well known that oxidative stress is enhanced in patients with end-stage renal disease. However, little is known about the relationship between serum antioxidant capacity and clinical outcome in hemodialysis (HD) patients. Methods: We examined the relationship between serum biomarkers of oxidative stress and clinical outcomes including all-cause mortality, hospitalization rate and incidence of cardiovascular events in HD patients. As biomarkers of oxidative stress, we measured serum levels of coenzyme Q10 (CoQ10) and biological antioxidant potential (BAP). Results: 108 patients were observed for 30 months as the follow-up periods. The survival group (n = 83) showed significantly higher BAP values compared with those in death groups (n = 25; p < 0.05). When serum BAP levels were divided into two groups by their median value, the group with higher BAP values had a better survival rate than that with lower BAP values on the Kaplan-Meier survival analysis (p = 0.05). Although serum levels of CoQ10 did not show any association with clinical outcomes, lower BAP was selected as an independent risk factor for all-cause mortality as well as the absence of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers therapy by age-adjusted Cox regression analysis. Conclusions: This study indicated that BAP could predict the prognosis of HD patients.

Phase IB randomized, double-blinded, placebo-controlled, dose-escalation study of polyphenon E in women with a history of hormone receptor-negative breast cancer.

TPS142 Background: Priorities in breast cancer (BC) chemoprevention include developing agents effective against hormone receptor (HR)-negative BC and validating intermediate biomarkers which correlate with BC risk. Numerous epidemiologic and preclinical studies support the anti- cancer and chemopreventive effects of green tea in BC. The main polyphenol of green tea, epigallacatechin gallate (EGCG), is a potent antioxidant which acts on multiple stages of carcinogenesis. The central hypothesis of this proposal is that the green tea polyphenol mixture, polyphenon E (Poly E), has activity for the secondary prevention of HR-negative BC. The primary objective of this phase IB trial is to demonstrate the safety of using Poly E over a 6- month period in patients with a history of HR-negative BC. Secondary exploratory objectives are to investigate the dose-related biologic effects of Poly E on breast tissue, radiographic, and serum-based biomarkers. Methods: This trial is a phase IB, randomized, double-blind, placebo-controlled study of oral Poly E 400 mg, 600 mg, or 800 mg bid for 6 months in 40 women with a history of stage I-III HR-negative BC (minimum of 6 months since completing chemotherapy, radiation therapy, or surgery; age 21-65). To date 40 patients have been enrolled. The primary endpoint of this dose escalation study is to determine the maximum tolerated dose of Poly E in this patient population according to the time-to-event continual reassessment method. Safety is assessed by monitoring clinical and laboratory parameters monthly for the duration of the study. Patients undergo a random core biopsy and mammogram of the contralateral breast at baseline and 6 months and serial blood/urine collections every 2 months. Laboratory correlates include breast tissue-based biomarkers (Ki-67, cleaved caspase-3, ER, EGFR, p53), mammographic density, serum hormone metabolites (estradiol, testosterone, IGF-I, IGFBP-3, SHBG), inflammatory and oxidative stress biomarkers (serum CRP, urine PGE-M, 8-OHdG, isoprostane). This study tests the safety and potential efficacy of a novel BC chemopreventive agent and evaluates a new approach for testing these agents. No significant financial relationships to disclose.

Acute Fish Oil and Soy Isoflavone Supplementation Increase Postprandial Serum (n-3) Polyunsaturated Fatty Acids and Isoflavones but Do Not Affect Triacylglycerols or Biomarkers of Oxidative Stress in Overweight and Obese Hypertriglyceridemic Men

Chronic consumption of fish and fish oil high in (n-3) PUFA reduces triacylglycerols (TG) but may increase oxidative stress, whereas consumption of soy isoflavones may reduce oxidative stress. Elevated serum TG and oxidative stress are considered cardiovascular disease (CVD) risk factors, but the effects of acute (n-3) PUFA and soy isoflavones on these CVD risk factors are unknown. The purpose of the study was to determine the effects of acutely supplementing a high-fat, high-fructose meal with fish oil and isoflavone placebo (FO) and fish oil placebo and soy isoflavones (ISO). In a randomized, double-blind, placebo-controlled, crossover study, 10 overweight or obese men consumed a high-fat, high-fructose meal with 4 dietary supplement combinations: fish oil placebo and isoflavone placebo (placebo); fish oil and isoflavone placebo (FO); fish oil placebo and isoflavones (ISO); and fish oil and isoflavones (FO + ISO). Serum collected at baseline and at 2, 4, and 6 h postprandially was analyzed for fatty acids, isoflavones, TG, and oxidative stress biomarkers (lipid hydroperoxides, oxidized-LDL, total antioxidant status). FO significantly increased serum (n-3) PUFA and ISO increased serum isoflavones. The study meal significantly increased serum total fatty acids and TG without affecting oxidative stress biomarkers. Serum TG and oxidative stress biomarkers did not differ between treatments. The FO and ISO were bioavailable but did not attenuate the postprandial rise in serum TG. Neither the study meal nor the FO or ISO induced significant changes in oxidative stress biomarkers. The current study adds to a limited literature on the acute effects of FO and ISO interventions on postprandial biomarkers of CVD risk.

Longer‐term Effects of a Low Glycemic Index Diet on Glycemic Control in Type 2 Diabetes

BackgroundNut consumption, including peanuts, has been associated with a reduced risk of coronary heart disease (CHD). More recently, interest has grown in the potential value of including nuts in diets of individuals with diabetes.ObjectiveTo determine if tree nuts and peanuts improve glycemic control in non‐insulin dependent diabetes, as assessed by HbA1c and to assess whether these outcomes relate to improvements in CHD risk (serum lipids, blood pressure and oxidative stress and inflammatory biomarkers).MethodsApproximately 120 NIDDM subjects (BMI ≤32kg/m2) treated with oral hypoglycemic agents (HbA1c 6.5‐8.0%) were recruited to a 3 month parallel design study. Subjects were randomized to one of three treatments: 1) Test (Full Dose Nut Diet): Raw nuts were added as supplements to the subject's usual diet based on required energy intake (≥2,400kcal/d received 100g/d nuts, ≈600kcal; 1,600‐2,400kcal/d received 75g/d nuts, ≈450kcal; ≤1,600kcal/d received 50g/d, ≈300kcal); 2) Test (Half Dose Nut Diet): Subjects received half dose of nuts and half dose of control muffin according to calorie needs; and 3) Control: whole wheat muffins were matched with energy content of nut supplements. One‐week weighed diet histories were obtained and fasting blood samples collected at baseline and weeks 2, 4, 8, 10 and 12 for markers of glycemic control and CHD risk factors.ResultsFinal data to be presented.

An examination of the effects of the antioxidant Pycnogenol® on cognitive performance, serum lipid profile, endocrinological and oxidative stress biomarkers in an elderly population

The study examines the effects of the antioxidant flavonoid Pycnogenol on a range of cognitive and biochemical measures in healthy elderly individuals. The study used a double-blind, placebo-controlled, matched-pair design, with 101 elderly participants (60-85 years) consuming a daily dose of 150 mg of Pycnogenol for a three-month treatment period. Participants were assessed at baseline, then at 1, 2, and 3 months of the treatment. The control (placebo) and Pycnogenol groups were matched by age, sex, body mass index, micronutrient intake, and intelligence. The cognitive tasks comprised measures of attention, working memory, episodic memory, and psychomotor performance. The biological measures comprised levels of clinical hepatic enzymes, serum lipid profile, human growth hormone, and lipid peroxidation products. Statistically significant interactions were found for memory-based cognitive variables and lipid peroxidation products, with the Pycnogenol group displaying improved working memory and decreased concentrations of F2-isoprostanes relative to the control group.

Correlates of Oxidative Stress and Free-Radical Activity in Serum from Asymptomatic Shipyard Welders

Oxidative stress is believed to play a key role in the development of welding-induced disease. This study investigated the effects of welding fume exposure on correlates of oxidative stress in the serum of asymptomatic shipyard welders. Blood samples from 197 male welders and 150 unexposed male office workers were analyzed for manganese and lead. Serum was assayed for protein, albumin, total antioxidant status (TAS), manganese superoxide dismutase (Mn-SOD), aconitase, glutathione peroxidase (GPx), heat shock protein 70, isoprostane, and reactive oxygen species, using electron spin resonance and chemiluminescence. Comparisons between welders and control subjects on biomarkers of oxidative stress were made, and evaluated for the effects of age and smoking. Associations between blood levels of manganese and lead and biomarkers were also explored. Welding was associated with increases in serum protein, GPx, aconitase, TAS, and isoprostane levels compared with control subjects. These group differences were not altered by age or smoking. In welders and control subjects, age was significantly associated with changes in albumin, TAS, chemiluminescence, GPx, and Mn-SOD. In welders and control subjects, smoking resulted in a decrease in GPx, and in a significant interaction between smoking and chemiluminescence. There were significant correlations between manganese levels in welders' blood and chemiluminescence, GPx, and Mn-SOD, and between lead levels and albumin, TAS, GPx, and Mn-SOD. These results document that exposure to welding can cause changes in serum biomarkers of oxidative stress that may be valuable in clinical monitoring of disease development and in assessing whether further reduction of worker exposures is needed.

Do the serum oxidative stress biomarkers provide a reasonable index of the general oxidative stress status?

The oxidant status of an individual is assessed by determining a group of markers in noninvasive samples. One limitation when measuring these biomarkers is that they do not give information about tissue localization of oxidative stress. The present study was undertaken to establish whether the serum oxidative stress biomarkers are indicative of oxidative stress in tissues of an individual. To accomplish this, we determined a few generic markers of oxidation in serum and tissues of six groups of rats treated experimentally, to modulate their oxidative stress status. The correlation between serum and tissue levels was calculated for each marker. Also, for each tissue, the correlation between the values of these oxidative stress biomarkers was analysed. Our results show that only lipid peroxides in serum could be useful to predict the oxidative stress in tissues. No correlation was found between any of the oxidative stress markers in serum.