Plasma Trolox Equivalent Antioxidant Capacity Research Articles

Biomarker: Trolox equivalent antioxidant capacity and telomere length of Thai elderly people with frailty

Introduction: Thailand has a rapidly aging population; assessing frailty earlier with biochemical markers could identify many adverse outcomes such as disability, hospitalization, and death. We aimed to examine the correlation between Trolox equivalent antioxidant capacity (TEAC), thiobarbituric acid reactive substances (TBARS), and telomere length and frailty for elderly people in Northern Thailand.
 Methods: A cross-sectional study was performed between May 2017 and March 2018 with a total of 350 elderly aged 60 and older for frailty phenotype assessment by five frailty criteria including unintentional weight loss, exhaustion, slowness, low physical activities, and grip strength weakness. Twenty-eight subjects in both the frailty and non-frailty groups were analyzed for basic clinical parameters, including plasma TEAC, TBARS, and telomere length.
 Results: Alanine aminotransferase activity, albumin concentration, cholesterol level, and telomere length were significantly low in the frailty group. The albumin level, TEAC, and telomere length were significantly higher between the ages of 60 and 75 years compared to those with non-frailty over 75 years of age. Likewise, albumin and cholesterol levels were significantly higher in the frailty group aged 60–75 years. Albumin concentration, cholesterol level, TEAC, and telomere length were significantly higher in the non-frailty group when compared to the frailty group aged 60–75 years, but no significant difference was found among these biochemical parameters of frailty and non-frailty whose age was above 75 years.
 Conclusion: The reduction of albumin concentration, cholesterol level, TEAC, and telomere length supports the underlying mechanism of frailty screened by the frailty phenotype tool in a specific age range. However, further analyses with multi-parameters must be validated before the application in clinical diagnosis for frailty.

Experimental Woodsmoke Exposure During Exercise and Blood Oxidative Stress

The current laboratory study quantified blood oxidative stress to woodsmoke exposure. Participants inhaled woodsmoke during three randomized crossover exercise trials (Clean Air [0 μg/m], Low Exposure [250 μg/m], and High Exposure [500 μg/m], Woodsmoke [particulate matter less than 2.5 μm, PM2.5]). Trolox equivalent antioxidant capacity (TEAC), uric acid (UA), 8-isoprostanes (8-ISO), lipid hydroperoxides (LOOH), protein carbonyls (PC), nitrotyrosine (3-NT), 8-isoprostane, and myeloperoxidase (MPO) were quantified in Pre, immediately Post, and 1- (1Hr) hour post blood samples. UA decreased following Low Exposure, while plasma TEAC levels increased Post and 1Hr. LOOH levels decreased 1Hr Post (High Exposure), while 8-Iso increased following both smoke trials. PC and MPO were unchanged following all trials, while 3-NT increased over Clean Air. Blood oxidative stress occurred largely independent of PM2.5 concentrations. Future studies should employ longer duration smoke and exercise combined with physiologic parameters.

Dietary Phytochemicals Promote Health by Enhancing Antioxidant Defence in a Pig Model.

Phytochemical-rich diets are protective against chronic diseases and mediate their protective effect by regulation of oxidative stress (OS). However, it is proposed that under some circumstances, phytochemicals can promote production of reactive oxygen species (ROS) in vitro, which might drive OS-mediated signalling. Here, we investigated the effects of administering single doses of extracts of red cabbage and grape skin to pigs. Blood samples taken at baseline and 30 min intervals for 4 hours following intake were analyzed by measures of antioxidant status in plasma, including Trolox equivalent antioxidant capacity (TEAC) and glutathione peroxidase (GPx) activity. In addition, dose-dependent production of hydrogen peroxide (H2O2) by the same extracts was measured in untreated commercial pig plasma in vitro. Plasma from treated pigs showed extract dose-dependent increases in non-enzymatic (plasma TEAC) and enzymatic (GPx) antioxidant capacities. Similarly, extract dose-dependent increases in H2O2 were observed in commercial pig plasma in vitro. The antioxidant responses to extracts by treated pigs were highly correlated with their respective yields of H2O2 production in vitro. These results support that dietary phytochemicals regulate OS via direct and indirect antioxidant mechanisms. The latter may be attributed to the ability to produce H2O2 and to thereby stimulate cellular antioxidant defence systems.

Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity.

Dehydration is a common event associated with exercise. However, few studies have examined the effects of dehydration on plasma redox status in humans. Eighty-two athletes were recruited and baseline anthropometrics and blood samples were obtained. Athletes then engaged in a dehydration protocol, training until 3% of preweight body mass was lost. Athletes returned to the lab and had postdehydration blood collected. Athletes then consumed an isotonic drink until pre-exercise body weight was reestablished. Blood was then recollected (1 h post full rehydration (PFR)). Samples were centrifuged and the plasma snap frozen in liquid nitrogen and stored at -80 °C. Lipid and protein oxidative stress was determined by measuring F2-isoprostanes and protein carbonyls (PC), respectively. Antioxidant capacity was determined by the ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. Plasma osmolality was determined using an osmometer. Statistical analysis utilized a 1-way ANOVA with posthoc testing. Values are reported as mean ± SD. Plasma osmolality was significantly elevated immediately postdehydration (p ≤ 0.001) but decreased to baseline at PFR. Plasma TEAC increased immediately postdehydration and at PFR (p ≤ 0.001). FRAP increased immediately postdehydration (p ≤ 0.001) and decreased to below baseline at PFR (p ≤ 0.05). Conversely, F2-isoprostanes declined significantly from baseline to immediately postdehydration and then significantly rose at PFR (p ≤ 0.001), whereas PC declined at PFR (p ≤ 0.01). This study indicates that dehydration and exercise cause a significant increase in plasma osmolality and antioxidant potential immediately postexercise. We propose dehydration significantly elevates antioxidant concentration which suppresses F2-isoprostanes and PC.

Aspergillus awamori-fermented mung bean seed coats enhance the antioxidant and immune responses of weaned pigs.

The potential benefits of Aspergillus-fermented mung bean seed coats (FMSC) for weaned pigs remain unexplored. Both invitro and invivo experiments were employed to evaluate the potential of FMSC supplement on the growth, antioxidant and immune responses of weaned pigs. The total polyphenols and DPPH scavenging capability of ethanol extract of FMSC exhibited a greater (p<0.01) increase than those of pre-fermentation. With the addition of the polyphenol of FMSC extract, an increase in phagocytosis by neutrophils and proliferation of peripheral blood mononuclear cells (PBMC) were found. However, these observations were significantly inhibited (p<0.05) in those activated cells. Next, 96 weaned pigs were allotted with a randomized complete block design into four dietary treatments, including 0 (control), 600, 1200 or 1800mg/kg FMSC in a corn-soya bean meal basal diet for a 35-day trial. The pigs were injected with swine enzootic pneumonia (SEP) vaccines at day 3 and day 21 respectively. The results showed that dietary treatment failed to affect growth performance or serum SEP titre. The diet supplemented with 600-1800mg/kg FMSC decreased faecal lactoferrin on day 21 and increased plasma trolox equivalent antioxidant capacity (TEAC) and erythrocytes catalase activity, as well as decreased (p<0.01) plasma malondialdehyde (MDA) concentration on day 35. Diet supplementation of 1800mg/kg FMSC increased phagocytosis by neutrophils and PBMC proliferation induced by pokeweed mitogen (PWM). However, the polymorphonuclear leucocytes (PMN)-positive respiratory burst cells were decreased in the supplementation of 1200 or 1800mg/kg FMSC respectively. In addition, the serum haptoglobin concentration was decreased in the supplementation with 1200mg/kg FMSC. Taken together, FMSC enriches polyphenols with antioxidative and immune modulated properties. After feeding FMSC, an improvement in antioxidative capability and immunocompetence was found, implying that FMSC could provide as a feed additive at optimal level 1200mg/kg for weaned pigs.

Sex differences in the blood antioxidant defense system in juvenile rats with various genetic predispositions to hypertension.

This study investigated the contribution of blood oxidative stress (OS) to the development of hypertension, as well as sex differences in the antioxidant defense system (ADS) in genetic models of hypertension. Nine-week-old normotensive Wistar-Kyoto (WKY) rats, borderline hypertensive rats (BHR) and spontaneously hypertensive rats (SHR) of both sexes were used. Systolic blood pressure (SBP) was determined by tail-cuff plethysmography, the trolox equivalent antioxidant capacity (TEAC) and the concentration of lipid peroxides (LP) were determined in plasma. The activity of the antioxidant enzymes Cu/Zn-superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) was determined in erythrocytes. SBP was significantly elevated in BHR and SHR in both sexes. BHR and SHR males had a higher SBP than the respective females. Sex-dependent differences in the ADS were found only in SHR, in which TEAC, SOD and CAT were significantly higher in males than in females. No differences in TEAC, SOD, CAT and GPx were observed between BHR (males and females) and WKY controls. LP levels were similar in all the groups investigated. Significant positive correlations were observed between SBP and both SOD and CAT. TEAC correlated positively with SOD and LP. As no signs of oxidative damage to lipids were found in young BHR and SHR of either sex, OS in the blood does not seem to be causatively related to the development of hypertension in these rats. However, despite activated antioxidant defenses, the positive correlation between plasma TEAC and LP suggests that oxidative damage is progressing slowly and therefore it seems to be a consequence rather than the cause of hypertension.

Melatonin deprival modifies follicular and corpus luteal growth dynamics in a sheep model

This study assessed the effect of melatonin deprival on ovarian status and function in sheep. Experimental procedures were carried out within two consecutive breeding seasons. Animals were divided into two groups: pinealectomised (n=6) and sham-operated (n=6). The completeness of the pineal gland removal was confirmed by the plasma concentration of melatonin. Ovarian status was monitored by ovarian ultrasonography for 1 year to study reproductive seasonality. Follicular and corpus luteal growth dynamics were assessed during an induced oestrous cycle. As the effects of melatonin on the ovary may also be mediated by its antioxidant properties, plasma Trolox equivalent antioxidant capacity (TEAC) was determined monthly for 1 year. Pinealectomy significantly extended the breeding season (310±24.7 vs 217.5±24.7 days in controls; P<0.05). Both pinealectomised and sham-operated ewes showed a well-defined wave-like pattern of follicle dynamics; however, melatonin deficiency caused fewer waves during the oestrous cycle (4.3±0.2 vs 5.2±0.2; P<0.05), because waves were 1 day longer when compared with the controls (7.2±0.3 vs 6.1±0.3; P<0.05). The mean area of the corpora lutea (105.4±5.9 vs 65.4±5.9 mm(2); P<0.05) and plasma progesterone levels (7.1±0.7 vs 4.9±0.6 ng/ml; P<0.05) were significantly higher in sham-operated ewes compared with pinealectomised ewes. In addition, TEAC values were significantly lower in pinealectomised ewes compared with control ones. These data suggest that melatonin, besides exerting its well-known role in the synchronisation of seasonal reproductive fluctuations, influences the growth pattern of the follicles and the steroidogenic capacity of the corpus luteum.

Pomegranate Juice Augments Memory and fMRI Activity in Middle-Aged and Older Adults with Mild Memory Complaints

Despite increasing emphasis on the potential of dietary antioxidants in preventing memory loss and on diet as a precursor of neurological health, rigorous studies investigating the cognitive effects of foods and their components are rare. Recent animal studies have reported memory and other cognitive benefits of polyphenols, found abundantly in pomegranate juice. We performed a preliminary, placebo-controlled randomized trial of pomegranate juice in older subjects with age-associated memory complaints using memory testing and functional brain activation (fMRI) as outcome measures. Thirty-two subjects (28 completers) were randomly assigned to drink 8 ounces of either pomegranate juice or a flavor-matched placebo drink for 4 weeks. Subjects received memory testing, fMRI scans during cognitive tasks, and blood draws for peripheral biomarkers before and after the intervention. Investigators and subjects were all blind to group membership. After 4 weeks, only the pomegranate group showed a significant improvement in the Buschke selective reminding test of verbal memory and a significant increase in plasma trolox-equivalent antioxidant capacity (TEAC) and urolithin A-glucuronide. Furthermore, compared to the placebo group, the pomegranate group had increased fMRI activity during verbal and visual memory tasks. While preliminary, these results suggest a role for pomegranate juice in augmenting memory function through task-related increases in functional brain activity.

Leonurus sibiricusHerb Extract Suppresses Oxidative Stress and Ameliorates Hypercholesterolemia in C57BL/6 Mice and TNF-α Induced Expression of Adhesion Molecules and Lectin-Like Oxidized LDL Receptor-1 in Human Umbilical Vein Endothelial Cells

In Leonurus sibiricus herb extract (LHE)-supplemented animals, plasma cholesterol decreased and high-density lipoprotein-cholesterol increased, resulting in a lowered atherogenic index. The plasma trolox equivalent antioxidant capacity, levels of hepatic thiobarbituric acid-reactive substances, and protein carbonyl values decreased significantly in LHE-supplemented mice (p<0.05), whereas the hepatic antioxidant indicators were all significantly elevated (p<0.05). In human umbilical vein endothelial cells stimulated with tumor necrosis factor alpha, LHE significantly suppressed intracellular reactive oxygen species, LOX-1, and adhesion molecules. LHE supplementation may modulate the lipoprotein composition and attenuate oxidative stress by elevated antioxidant processes, thus suppressing the activation of inflammatory mediators. This is a possible mechanism of the anti-atherogenic effect.

Modulation of nucleotide excision repair in human lymphocytes by genetic and dietary factors

Gene-environment interactions determine inter-individual variations in nucleotide excision repair (NER) capacity. Oxidative stress was previously found to inhibit NER, thus supplementation with dietary antioxidants could prevent this inhibition, especially in genetically susceptible subjects. To study the effects of genetic polymorphisms in NER-related genes and dietary intake of antioxidants on an individual's NER capacity, lymphocytes of 168 subjects were isolated before and after a 4-week blueberry and apple juice intervention. Twelve genetic polymorphisms in NER genes XPA, XPC, ERCC1, ERCC2, ERCC5, ERCC6 and RAD23B were assessed by multiplex PCR with single base extension. Based on specific genotype combinations, a subset of individuals (n 36) was selected for phenotypical assessment of NER capacity, which was significantly affected by the total sum of low-activity alleles (P = 0.027). The single polymorphism XPA G23A was the strongest predictor of NER capacity (P = 0.002); carriers of low-activity alleles AA had about three times lower NER capacity than XPA GG carriers. NER capacity assessed before and after intervention correlated significantly (R(2) 0.69; P < 0.001), indicating that inter-individual differences in NER capacity are maintained over 4 weeks. Although the intervention increased plasma trolox equivalent antioxidant capacity from 791 (SE 6.61) to 805 (SE 7.90) microm (P = 0.032), on average it did not affect NER capacity. Nonetheless, carriers of twelve or more low-activity alleles seemed to benefit from the intervention (P = 0.013). Among these, carriers of the variant allele for RAD23B Ala249Val showed improved NER capacity upon intervention (P = 0.020). In conclusion, improved NER capacity upon dietary intervention was detected in individuals carrying multiple low-activity alleles. The XPA G23A polymorphism might be a predictor for NER capacity.

Fructooligosaccharide supplementation improved blood antioxidative status in the constipated elderly subjects

Fructooligosaccharide (FO) has been shown to stimulate the growth of bifidobacteria in men which may beneficially exert antioxidative effect. We have demonstrated FO supplementation promote fecal bifidobacteria population in constipated age population. This study further investigated effects of FO supplementation on blood antioxidative status in these subjects. Ten elderly adults (6 males) aged 74.0 ± 3.3 (mean ± SD) completed the single‐blind, placebo‐ and diet‐controlled study that consisted a 4‐wk placebo (3 g/d fructose syrup), a 4‐wk FO (10 g/d oligosaccharides) and a 4‐wk post period. Fasting bloods were collected at the end of each period for analysis of antioxidants, trolox equivalent antioxidant capacity (TEAC), thiobarbitituric acid‐reactive substances (TBARS) in the plasma. DNA strand breakage of whole blood, indicator of blood peroxidation, was determined using single‐cell electrophoresis (comet) assay. Results (means ± SDs) indicated that FO supplementation significantly increased plasma vitamin C level from 4.5 ± 1.1 to 11.9 ± 3.4 μM (P &lt; 0.05 vs placebo) and tended to increase the plasma TEAC, vitamin E and GSH levels (P &gt; 0.05). Plasma TBARS level was 13.1 ± 1.5 mM in the placebo period, which was significantly reduced to be 11.0 ± 1.6 mM in the FO period (by 16%, P &lt; 0.05) and 10.3 ± 1.3 mM in post period (P &lt; 0.05). The DNA strand breaks of whole blood was significantly reduced by 56% (P&lt;0.05) with FO supplementation, and this effect lasted through the post period. Therefore, this study suggested that supplementation of FO exerted prolonged beneficial effects on plasma antioxidant capacity in constipated elderly subjects. This research was supported by the National Science Council 96‐2320‐B‐040‐031‐MY3, Taiwan.

맹종죽 줄기 추출물을 투여한 본태성 고혈압 쥐(SHR)의 ACE 저해 활성 및 혈압 강하 효과

Dept. of Food Science Institute, Inje University, Gimhae 621-749, KoreaAbstractThis study investigated the anti-hypertensive effect of Phyllostachys pubescens culm extract (PCE) by examining its effects on renal angiotensin-converting enzyme (ACE) inhibition and blood pressure using the spontaneously hypertensive rat (SHR) system. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly for 8 weeks. Also, total antioxidant capacity and protein oxidation of tissues were examined by plasma Trolox Equivalent Antioxidant Capacity assay (TEAC) and hepatic protein carbonyl values, respectively. Twenty male SHR were randomly divided into four groups: PCE50, PCE100, and PCE500 (50, 100, and 500 mg of PCE per kilogram bodyweight daily, respectively), and control group. At week 2, the SBP in all PCE groups appeared to be significantly lower than the control (p<0.05), whereas the DBP were not different until week 4 (p<0.05). At week 8, SBP in the PCE500 was lower by 20% than the control. PCE groups considerably suppressed ACE dose-dependently compared with the control. Plasma TEAC and hepatic protein carbonyl values indicated increased antioxidative activity due to the PCE feed. No adverse effect was observed on the liver of SHR as there was no difference for the GOT and GPT values among the groups. Results of this study suggest that ACE inhibition may be one possible mechanism for the blood pressure lowering effect of PCE; thus, long term consumption of PCE may be beneficial in preventing high blood pressure along with the increased antioxidative status.Key words: Phyllostachys pubescens culm (PCE) extract, ACE inhibitory activity, antioxidant effect, blood pressure, hypertension

A Lignan Complex Isolated from Flaxseed Does Not Affect Plasma Lipid Concentrations or Antioxidant Capacity in Healthy Postmenopausal Women ,

A lignan complex rich in the plant lignan secoisolariciresinol diglucoside (SDG) was isolated from flaxseed. SDG is metabolized by the colonic microflora to the mammalian lignans enterodiol (END) and enterolactone (ENL), and was hypothesized to reduce plasma lipid concentrations and improve antioxidant capacity. The aim of this study was to investigate the effects of a lignan complex, providing 500 mg/d of SDG, on serum concentration and urinary excretion of ENL, plasma lipids, serum lipoprotein oxidation resistance, and markers of antioxidant capacity. Healthy postmenopausal women (n = 22) completed a randomized, double-blind, placebo-controlled, crossover study. Women consumed daily a low-fat muffin, with or without a lignan complex, for 6 wk, separated by a 6-wk washout period. Serum ENL concentration, urinary ENL excretion, plasma concentrations of total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), triacylglycerol (TAG), serum lipoprotein oxidation lag time, plasma Trolox-equivalent antioxidant capacity (TEAC), and ferric reducing ability of plasma (FRAP) were measured at the beginning and end of each intervention period. ENL concentrations in serum (P < 0.001) and ENL urinary excretion (P < 0.001) were significantly higher after the lignan complex intervention period compared with placebo. Plasma concentrations of TC, LDL-C, HDL-C, TAG, lipoprotein oxidation lag time, TEAC and FRAP were not affected. Daily consumption for 6 wk of a low-fat muffin enriched with a lignan complex significantly increased serum ENL concentrations and urinary ENL excretion in healthy postmenopausal women, but had no effect on plasma lipid concentrations, serum lipoprotein oxidation resistance, or plasma antioxidant capacity.

Oral Amino Acid Administration Decreases Oxidative Stress and Improves Brachial Reactivity in Elderly Individuals

Atherosclerosis is a major cause of death in elderly individuals. Endothelial dysfunction is recognized as a key early event in atherogenesis. In the present study, we evaluated the possible beneficial effect of amino acid administration on endothelial regulation in elderly subjects. A total of 25 healthy elderly subjects were administered essential amino acids (EAA) for 4 months. Before and after EAA administration, each subject underwent brachial reactivity investigation with and without an intra-arterial infusion of 4 micromol/min of N(G)-monomethyl-l-arginine (L-NMMA), an inhibitor of nitric oxide (NO) synthase. At baseline, age correlated with free plasma insulin growth factor-1 IGF-1 (r = -0.48; P < .01), plasma Trolox equivalent antioxidant capacity (TEAC) (r = -0.40; P < .04), and thiobarbituric acid-reactive substances (TBARS) (r = 0.42, P < .04), and homeostasis model assessment (HOMA) index (r = 0.45, P < .03), as well as with changes in diameter (r = -0.49, P < .01) and flow (r = -0.43, P < .03). Administration of EAA was associated with a significant increase in plasma TEAC (P < .001) and decline in plasma TBARS (P < .001) and with improvement in changes in diameter (7.15 +/-1.10 v 8.98 +/-1.80, P < .001) and flow (5.6 +/-1.2 v 6.4 +/- 1.2, P < .03). These latter two associations were independent of changes in HOMA index (P < .04 for both correlations). The beneficial effects of EAA administration on brachial reactivity were partly attenuated by L-NMMA. Administration of EAA may improve brachial reactivity in elderly persons and may also protect against the development of atherosclerosis via the rise in plasma-free IGF-1 levels.

Residual C-peptide secretion and endothelial function in patients with Type II diabetes

Recent studies have demonstrated that C-peptide exerts beneficial effects on endothelial function. To investigate the relationship between residual pancreatic C-peptide secretion and endothelial function in patients with well controlled or poorly controlled Type II diabetes, we studied 100 patients with Type II diabetes that were free from diabetic neuropathy. In all patients, insulin resistance, residual pancreatic C-peptide secretion, endothelial function and oxidative stress were investigated using the homoeostasis model assessment (HOMA) index, glucagon bolus test, brachial reactivity, Trolox equivalent antioxidant capacity (TEAC) and thiobarbituric acid-reacting substances (TBARS). The patients were categorized into quartiles on the basis of plasma HbA(1c) (glycated haemoglobin) concentration. Analysis of the data showed significant increases in plasma glucose concentration, HOMA index, microalbuminuria and TBARS, and significant decreases in plasma C-peptide, AUC (area under the curve) plasma C-peptide and TEAC, through the different quartiles (from the lowest to the highest HbA(1c) concentration). With regard to parameters of endothelial function, changes in diameter showed a significant declining trend through the different quartiles. Endothelial-dependent changes in diameter were independently and significantly associated with AUC C-peptide levels, TEAC and TBARS. In conclusion, our study demonstrated that patients with Type II diabetes with good residual C-peptide secretion are better protected from endothelial dysfunction that those with poor C-peptide secretion.

Plasma carotenoids, tocopherols, and antioxidant capacity in a 12-week intervention study to reduce fat and/or energy intakes

Objective: We examined plasma levels of carotenoids, tocopherols, and total antioxidant activity in women before and after dietary intervention to reduce fat and/or energy intakes. Dietary fat and energy may affect intake and bioavailability of carotenoids and tocopherols, and these micronutrient levels in turn can contribute to the antioxidant capacity of plasma. Methods: Women were randomized onto one of four diets for 12 wk: non-intervention, low fat (15% of energy from fat with maintenance of energy intake), low energy (25% energy reduction with maintenance of percentage of energy from fat), and combined low fat and low energy. Fasting plasma was available for analysis from a subset ( n = 41) of women enrolled in the study. Results: Levels of carotenoids and tocopherols did not change significantly over 12 wk on any diet arm, despite a modest but statistically significant increase in fruit and vegetable intake in the women following the low-fat diet (from 3.3 to 5.2 servings/d excluding potatoes). Levels of Trolox-equivalent antioxidant capacity (TEAC), total cholesterol, and two major plasma antioxidants (urate and bilirubin) also did not change significantly. Of the individual micronutrients measured, lycopene and lutein/zeaxanthin correlated most strongly with TEAC values, and the correlation with lycopene was statistically significant before intervention. Conclusions: The decreases in dietary fat and energy intakes in this study were quite large, but this did not appear to have detrimental effects on plasma micronutrient levels, nor did it appreciably affect plasma antioxidants. Because lycopene levels were significantly associated with plasma TEAC before intervention, interventions that increase levels of lycopene might be more likely to increase the antioxidant capacity of plasma.

The effect of the trolox equivalent antioxidant capacity (TEAC) in plasma on the formation of 4-aminobiphenylhaemoglobin adducts in smokers

Smokers are exposed to a number of carcinogenic compounds including aromatic amines such as 4-aminobiphenyl. Antioxidants are thought to be involved in the defence against the damaging effect of such carcinogens. Recently it has been shown that plasma antioxidant status in smokers is diminished compared with non-smokers. In this study we investigated in 40 smokers whether the trolox equivalent antioxidant capacity (TEAC) in plasma could be quantitatively related to exposure to cigarette smoke. The biomarkers 4-aminobiphenylhaemoglobin (4-ABP-Hb) adduct and cotinine were determined as indices of cigarette smoke exposure. A correlation between 4-ABP-Hb adduct levels and plasma cotinine levels was found for the whole population studied, who smoked 4-70 cigarettes per day (n = 40, r2 = 0.12, p = 0.03). A significant inverse relationship was found between TEAC and 4-ABP-Hb levels (n = 40, r2 = 0.17, p = 0.008). Multiple regression analysis showed a strong relationship between 4-ABP-Hb levels and plasma TEAC and cotinine levels (n = 40, r2 =0.29, p = 0.002). These findings provide strong evidence that the 4- ABP-Hb adduct represents a valuable biomarker of (internal) exposure to tobacco smoke, and also that the formation of this marker is dependent on the plasma antioxidant status. The multiple regression analysis results show that the measure of effect (4-ABP-Hb adduct formation) is largely determined by dose (cotinine) and protection (TEAC).

Is there any relationship between plasma antioxidant capacity and lung function in smokers and in patients with chronic obstructive pulmonary disease?

BACKGROUNDIt has been suggested that oxidative stress is an important factor in the pathogenesis of chronic obstructive pulmonary disease (COPD). We have shown that an oxidant/antioxidant imbalance occurs in the...

Total plasma antioxidant capacity in cystic fibrosis.

Several studies have demonstrated ongoing oxidative stress in cystic fibrosis (CF). With the complexity of the antioxidant network, measurement of individual antioxidants does not necessarily assess how they work in combination. One measure that has been proposed as a gauge of total plasma antioxidant capacity is the Trolox-equivalent antioxidant capacity (TEAC) of plasma. We decided to look at plasma TEAC levels in children with CF, and relate this measure to their nutritional status, lung function, and blood measurements of several known antioxidants. We hypothesized that values in general would be lower than healthy control values, especially during acute pulmonary exacerbations. Twenty-nine children were evaluated, five of whom were during an acute pulmonary exacerbation. Height and weight, expiratory spirometry, and lung volumes were assessed, as were serum concentrations of vitamins A and E, uric acid, albumin, and lymphocyte glutathione (GSH) concentrations. TEAC values for nonhospitalized patients (1.40 +/- 0. 20 mmol/L) were not different from laboratory control values (1.35 +/- 0.11 mmol/L), but greater than values for hospitalized patients (1.09 +/- 0.17 mmol/L). TEAC correlated with anthropometric values (height: r = 0.39, P < 0.03; weight: r = 0.50, P < 0.01; body mass index: r = 0.47, P < 0.01), and pulmonary function (forced expiratory volume in 1 sec: r = 0.43, P < 0.02; residual volume/total lung capacity: r = -0.42, P < 0.03), but not with age. Univariate correlation with blood measurements demonstrated a significant correlation of TEAC with uric acid (r = 0.49, P < 0.02), but not with albumin, vitamins A or E, or lymphocyte GSH. Multiple regression analysis demonstrated a correlation between TEAC and uric acid, albumin, and lymphocyte GSH in the non-hospitalized group (r(2) = 0.38, P < 0.03). We conclude that TEAC appears to represent a mixed antioxidant response, rather than response to a single antioxidant. While being responsive to oxidative stress, the mechanism of the response may differ between clinical situations, such that the clinical significance of changes in plasma TEAC remains to be defined.

Systemic and pulmonary oxidative stress in idiopathic pulmonary fibrosis

An oxidant/antioxidant imbalance has been proposed in patients with idiopathic pulmonary fibrosis (IPF). We tested this hypothesis by measuring various parameters of the oxidant/antioxidant balance in the plasma of 12 patients with IPF (7 nonsmokers and 5 smokers); in the bronchoalveolar lavage fluid (BALF) of 24 patients with IPF (17 nonsmokers and 7 smokers) and 31 healthy subjects (23 nonsmokers and 8 smokers). The trolox equivalent antioxidant capacity (TEAC) in plasma and BALF was lower in nonsmoking patients with IPF (plasma 0.55 ± 0.1 mM, p < .001; BALF 4.8 ± 1.2 μM, mean ± SEM, p < .01), compared with healthy nonsmokers (plasma 1.33 ± 0.03 mM; BALF 10 ± 2 μM). Similar trends in plasma and BALF TEAC were observed in smoking patients with IPF in comparison with healthy smokers. The decrease in BALF TEAC was concomitant with a decrease in BALF protein thiol levels, but the decrease TEAC levels in plasma in IPF patients was not accompanied by a decrease in protein thiol levels. Reduced glutathione (GSH) was lower in BALF in nonsmoking patients with IPF (1.0 ± 0.1 μM) compared with healthy nonsmokers (2.3 ± 0.2 μM, p < .001). In contrast, GSH levels were higher in smoking patients with IPF (5.2 ± 1.1 μM, p < .001) than in nonsmoking patients. GSSG levels were not different in any of the groups. The levels of products of lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) in plasma and BALF were significantly increased in both smoking (plasma 2.2 ± 0.5 μM, p < .01; BALF 0.18 ± 0.04 μM, p < .001), and nonsmoking (plasma 2.1 ± 0.3 μM, p < .01; BALF 0.22 ± 0.05 μM, p < .001) IPF patients, compared with healthy nonsmokers (plasma 1.4 ± 0.3 μM; BALF 0.05 ± 0.004 μM). These data show evidence of oxidant/antioxidant imbalance in the lungs of patients with IPF, which is also reflected as systemic oxidant stress.