Plasma Antioxidant Concentrations Research Articles

Status of lipidsoluble antioxidants and TRAP in patients with Crohn's disease and healthy controls.

To assess the status of lipidsoluble antioxidants (carotenoids, tocopherols, ubiquinone), retinol and their correlation with TRAP (total radical-trapping antioxidant potential) in patients with Crohn's disease. Prospective case-control study. Clinic of Internal Medicine IV/Department of Gastroenterology and Hepatology, University of Vienna Medical School. Plasma antioxidant concentrations were determined in patients with Crohn's disease (n = 24) to evaluate the antioxidant capacity compared to healthy controls (n = 33). Additionally, plasma TRAP (total radical-trapping antioxidant potential) was measured in 13 patients and 22 controls. All investigated carotenoids (alpha-carotene, beta-carotene and cryptoxanthin) were significantly decreased in patients with Crohn's disease (10.2 +/- 9.3, 16.2 +/- 12.4 and 7.8 +/- 5.5 microg/dl) compared to controls (13.3 +/- 5.1, 34.7 +/- 18.8 and 48.5 +/- 38.4 microg/dl respectively), whereas gamma-tocopherol and ubiquinone were significantly elevated in patients (0.14 +/- 0.07 microg/dl and 82.3 +/- 41.5 microg/dl, controls: 0.09 +/- 0.04 microg/dl and 60.8 +/- 30.0 microg/dl, respectively). Retinol and alpha-tocopherol did not significantly differ from controls. The total radical-trapping antioxidant potential (TRAP) was significantly lower in patients (1.11 +/- 0.28 micromol/l) compared to controls (1.34 +/- 0.26 micromol/l). Antioxidants were neither related to duration or severity of disease nor to disease activity. In patients with Crohn's disease several plasma antioxidant parameters are altered and the total radical-trapping antioxidant potential is decreased.

Serum malondialdehyde concentration in babies with hyperbilirubinaemia

AIMTo determine lipid peroxide concentrations in the first 10 days of life.METHODSMalondialdehyde concentrations were investigated in neonates with or without hyperbilirubinaemia during the first 10 days of life.RESULTSSerum malondialdehyde concentrations...

The impact of antioxidants on chronic disease in ageing and in old age.

The antioxidant defense system is important in maintaining cellular homeostasis and preventing oxidative stress. Antioxidants are important dietary components contributing to a general slowing of ageing processes (e.g. cataract formation), but also in protecting particularly vulnerable sites from developing tissue injuries resulting in chronic diseases. This suggests that we should aim at certain minimum threshold concentrations of plasma antioxidants. In the near future, it is well possible that the amount of nutrients necessary to prevent or to reduce the risk for chronic diseases will be the more important issue than the amount it takes to prevent deficiencies. In order to achieve optimal nutritional levels, particularly elderly may benefit from the use of supplements during periods of stress or compromised nutrient intake. The highly interactive antioxidative system in the body strongly suggests that a well-balanced adequate intake of different antioxidants will be superior in its protective action to the supplementation with one single compound. It should be possible to resolve in the near future the question whether two days' RDA's are still adequate or whether the intake should be revised upwards.

Micronutrient antioxidants and smoking.

Cigarette smoking is a major risk factor in such human diseases as cardiovascular disease (especially atherosclerosis), lung cancer (the leading world-wide cancer killer), and chronic obstructive pulmonary disease (COPD). An avalanche of studies has suggested that a diet rich in fruit and vegetables is associated with decreased risk for atherosclerosis and cancer. However, the dietary intake of fruits and vegetables, as well as antioxidant micronutrients, is decreased in smokers. This, along with evidence of increased utilization of ascorbic acid and alpha-tocopherol, possibly on the basis of increased oxidative stress, contributes to the low plasma antioxidant concentrations seen in many smokers. This review addresses selected mechanistic considerations of this relationship.

Cisplatin combination chemotherapy induces a fall in plasma antioxidants of cancer patients

Antioxidants protect the body against cellular oxidative damage and thus some of the adverse effects induced by cisplatin and other cytostatic drugs. The effect of cisplatin-combination chemotherapy on concentrations of plasma antioxidants was studied in 36 cancer patients, including osteosarcoma and testicular carcinoma patients. Eight to 15 days after the start of each cytostatic drug infusion concentrations of various plasma antioxidants were measured and compared to pretreatment values: vitamin C and E, uric acid and ceruloplasmin levels fell significantly (P < 0.01-0.005) and returned to baseline levels before the start of the next chemotherapy cycle. Levels of the antioxidants bilirubin albumin and the ratio vitamin E/cholesterol + triglycerides measured three weeks after the start of chemotherapy significantly decreased compared to pretreatment levels and remained low thereafter (P < 0.001-0.002). Dietary intake of antioxidants and anthropometric measurements, evaluated in 14 patients did not change during the whole treatment period. Cisplatin-combination chemotherapy induces a fall in plasma antioxidant levels, that may reflect a failure of the antioxidant defense mechanism against oxidative damage induced by commonly used anticancer drugs. This probably results from consumption of antioxidants caused by chemotherapy induced-oxidative stress as well as renal loss of water-soluble, small molecular weight antioxidants such as uric acid.

Inhibition of oxidative DNA damage, 8-OHdG, and carbonyl contents in smokers treated with antioxidants (vitamin E, vitamin C, β-carotene and red ginseng)

The chemopreventive effects of antioxidants (vitamin E, β-carotene, vitamin C and red ginseng) on oxidative DNA and protein (globin) damages were comparatively investigated in the peripheral blood of smokers (≥20 cigarettes/day). Smokers showed a lower baseline level of plasma micronutrients (vitamin C and β-carotene) ( P<0.01) and higher baseline level of oxidative DNA or protein damage than non-smokers ( N=5; P<0.05). During daily supplementation of antioxidants (200 IU vitamin of E, 9 mg of β-carotene, 500 mg of vitamin C, or 1.8 g of red ginseng) for 4 weeks, smokers plasma antioxidant concentrations increased linearly, while their mean levels of 8-hydroxydeoxyguanosine (8-OHdG) and carbonyl contents decreased compared with those in smokers supplemented with a placebo ( P<0.05). Levels of urinary and plasma cotinine remained steady in smokers regardless of supplementation with antioxidants. 8-OHdG and carbonyl content decreased in a time-dependent manner (as the total intake dose increased) after supplementation with vitamin E (8-OHdG, 33.8%; carbonyl content, 43.6%) or red ginseng (8-OHdG, 31.7%; carbonyl content, 21.3%). These preliminary data suggest that supplementation with antioxidants might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking.

Could antioxidants play a role in high rates of coronary heart disease in the Czech Republic?

To compare plasma levels of antioxidant vitamins in the Czech population with those in a western European population, and to investigate whether plasma levels of antioxidant vitamins in Czech population are related to risk of MI. The study has two parts: a cross-sectional survey and a population based case-control study. Adult population in two districts of the Czech Republic, and London based civil servants group as the comparison. A random sample of men and women aged 25-64y resident in two districts were selected for the cross- sectional survey. Subjects in the age group 40-49 y were compared to a sample of British civil servants of the same age enrolled in the Whitehall II Study. Men in the Czech sample served as controls to 52 male cases of first non-fatal myocardial infarction (MI) which occurred in the same population. Plasma samples were obtained from venepuncture during an interview in hospital in the population sample and immediately after hospitalization in the MI cases. Plasma levels of beta-carotene and alpha-tocopherol, and the event of MI. Identical protocol and one laboratory was used for all analyses. The mean plasma levels of beta-carotene and alpha-tocopherol in healthy Czech men and women were substantially lower than in a subsample of British civil servants examined in the same laboratory. Smoking was strongly related to beta-carotene in both populations but differences between Czechs and Brits were present in both smokers and non-smokers. In the case-control study among Czech men, low levels of the vitamins were strongly related to an increases risk of MI. Age-adjusted odds ratios for concentrations below the median were 3.33 (95% confidence interval 1.43-8.33) for beta-carotene and 1.89 (0.94-3.45) for alpha-tocopherol; further adjustment for a range of variables reduced these estimates only slightly. Plasma concentrations of antioxidants in the Czech population appeared to be very low, and men with low levels of these substances are at increased risk of MI. This indicates that sub-optimal intake of antioxidants or related dietary factors may have played a role in the high rates of coronary heart disease in this population.

Relationship between blood antioxidants and occupational exposure to polycyclic aromatic hydrocarbons in coke oven workers.

We investigated if blood Cu++/Zn++ superoxide dismutase, glutathione peroxidase, and catalase activities are increased and total plasma antioxidant concentration is decreased in coke oven workers exposed to polycyclic aromatic hydrocarbons. Ninety-six coke oven workers participated in the study. Nonexposed workers (n = 105) were randomly sampled among power plant workers in the same age range. The examination included a questionnaire on health status, occupational history, smoking, and dietary habits. Blood samples completed the examination. Coke oven workers were classified into low-, middle-, and high-exposure groups based on the benzo[a]pyrene (B[a]P) air concentrations and were further classified into the categories "topside" and "non-topside," according to their proximity to the ovens. Erythrocyte glutathione peroxidase activity increased with age (r = 0.18, P = 0.061) in power plant workers, whereas plasma glutathione peroxidase activity decreased with age (r = -0.18, P = 0.068) and erythrocyte glutathione peroxidase activity was inversely correlated with the number of cigarettes per day (r = -0.28, P = 0.08) in coke oven workers. Comparison of blood antioxidant enzyme activities and total plasma antioxidant concentration between coke oven and power plant workers showed that erythrocyte glutathione peroxidase activity was significantly lower in coke oven workers, even after adjustment for potential confounding factors. No differences were found either in other blood antioxidant enzyme activities or in total plasma antioxidant concentration between coke oven and power plant workers. Moreover, no trends toward decreased glutathione peroxidase activity among the three subgroups of B[a]P exposure were observed, and no differences either in blood antioxidant enzyme activities or in total plasma antioxidant concentration between the two groups of job categories were found. Production of reactive oxygen species seems not to be increased in coke oven workers.

Relations between occupational exposure to coal mine dusts, erythrocyte catalase and Cu++/Zn++ superoxide dismutase activities, and the severity of coal workers' pneumoconiosis.

OBJECTIVES: To better understand the relations between occupational exposure, blood antioxidant enzyme activities, total plasma antioxidant concentration, and the severity of coal workers' pneumoconiosis (CWP). METHODS: Blood samples were obtained...

Oxidative DNA damage in vivo: Relationship to age, plasma antioxidants, drug metabolism, glutathione-S-transferase activity and urinary creatinine excretion

Oxidative DNA modification has been implicated in development of certain cancers and 8-oxodG, the most abundant and mutagenic DNA modification, has for some time been considered a biomarker of this activity. Urinary excretion of 8-oxodG over 24h has been used to estimate the rate of damage to DNA, and animal studies have supported this rationale. Reported determinants include tobacco smoking, heavy exercise, environmental pollution and individual oxygen consumption.Samples from three published studies were used to determine the association of urinary 8-oxodG excretion with age, plasma antioxidants, the glutathione-S-transferase phenotype and the activity of the xenobiotic metabolising enzyme CYP1A2. In the age range 35–65 years, age was not related to urinary 8-oxodG excretion, and there were no relations to either the glutathione-S-transferase phenotype or to the plasma antioxidants: vitamin C, alpha-tocopherol, beta-carotene, lycopene or coenzyme Q10. The activity of CYP1A2 showed a significant correlation in two of the three studies, as well as a significant correlation of 0.26 (p < 0.05) in the pooled data set. Regression analysis of CYP1A2 activity on 8-oxodG indicated that 33% increase in CYP1A2 activity would correspond to a doubling of 8-oxodG excretion. This finding needs to be confirmed in independent experiments.Spot morning urine samples can under certain circumstances be used to estimate 8-oxodG excretion rate provided that creatinine excretion is unchanged (in paired experiments) or comparable (in un-paired experiments), as evaluated from the correlation between 8-oxodG excretion in 24h urine samples and in morning spot urine samples corrected for creatinine excretion (r = 0.50, p < 0.05).We conclude that 8-oxodG excretion is determined by factors like oxygen consumption and CYP1A2 activity rather than by factors like plasma antioxidant concentrations.

Nasal Cavity Lining Fluid Ascorbic Acid Concentration Increases in Healthy Human Volunteers Following Short Term Exposure to Diesel Exhaust

To determine if diesel exhaust (DE) exposure modifies the antioxidant defense network within the respiratory tract lining fluids, a randomized, single blinded, crossover control study using nasal lavage and flexible video bronchoscopy with bronchial and broncho-alveolar lavage was performed. Fifteen healthy, nonsmoking, asymptomatic subjects were exposed to filtered air or diluted diesel exhaust (300mg m-3 partic-ulates, l.6ppm nitrogen dioxide) for one hour on 2 separate occasions, at least three weeks apart. To examine the kinetics of any DE-induced antioxidant reactions, nasal lavage fluid and blood samples were collected prior to, immediately after, and 51/2 hours post exposure. Bronchoscopy was performed 6 hours after the end of DE exposure. Ascorbic acid, uric acid and reduced glutathone (GSH) concentrations were determined in nasal, bronchial, bronchoalveolar lavage and plasma samples. Malondialdehyde (MDA) and protein carbonyl concentrations were determined in plasma and bronchoalveolar lavage samples. Nasal lavage ascorbic acid concentration increased 10-fold during DE exposure [1.02 (0.26–2.09) Vs 7.13 (4.66–10.79) μmol/L-1, but returned to basal levels 5.5 hours post-exposure [0.75 (0.26–1.51) μmol/L-']. There was no significant effect of DE exposure on nasal lavage uric acid or GSH concentration. DE exposure did not influence plasma, bronchial wash, or bronchoalveolar lavage antioxidant concentrations and no change in MDA or protein carbonyl concentrations were found. The physiological response to acute DE exposure is an increase in the level of ascorbic acid in the nasal cavity. This response appears to be sufficient to prevent further oxidant stress in the respiratory tract of normal individuals.

The effect of Simvastatin on the plasma antioxidant concentrations in patients with hypercholesterolaemia

The aim of the study was to monitor the antioxidant status of patients with hypercholesterolaemia during treatment with Simvastatin. Forty-seven patients, of whom 25 had confirmed familial hypercholesterolaemia (FH), were treated with 10 or 20 mg of Simvastatin per day for 14 weeks. As expected, total cholesterol and LDL cholesterol concentrations decreased considerably, while HDL cholesterol concentrations increased during drug treatment. In neither FH nor non-FH patients were any significant changes observed for retinol status, while plasma vitamin C concentrations were also not adversely affected by the drug therapy. In both patient groups Simvastatin therapy led to a significant decrease in plasma α-tocopherol ( P<0.05) concentrations, however, the α-tocopherol/total cholesterol ratio increased by 9.1 ( P<0.01) and 12.1% ( P<0.01) in FH and non-FH patients, respectively, during the 14-week treatment period. The coenzyme Q 10/total cholesterol ratio did not change significantly in non-FH patients, but was significantly lower ( P<0.05) than the baseline ratio after 4 and 14 weeks of Simvastatin treatment in FH patients. The α-tocopherol/total cholesterol ratio of FH patients remained consistently and significantly lower ( P<0.01) compared with non-FH patients, indicating that LDL from the former group may be more vulnerable to free radical-mediated damage and lipid peroxidation. Our results suggest that the significant decline in circulating α-tocopherol and coenzyme Q 10 concentrations was mainly a function of the decrease in serum total cholesterol concentrations.

Randomised controlled trial of effect of fruit and vegetable consumption on plasma concentrations of lipids and antioxidants

Objectives: To determine the extent to which plasma antioxidant concentrations in people with habitual low intake of fruit and vegetables respond to increased intakes of these foods. To examine whether...

Dietary Intake and Plasma Concentrations of Vitamin E, Vitamin C, and Beta Carotene in Patients with Coronary Artery Disease

Evidence suggests that the antioxi-dant micronutrients, vitamin E, vitamin C, and beta carotene, may be protective against coronary artery disease, perhaps through inhibition of the oxidation of low-density lipoprotein (LDL) (1–5). Previous studies have described the relationship between anti-oxidant micronutrient intake and plasma antioxidant concentrations in healthy volunteers (3,4,6). Studies of this relationship in patients with coronary artery disease, however, are limited. The purpose of this study was to examine the relationship between dietary intake and plasma concentrations of antioxidant micronutrients in these patients. We asked the question: What are the determinants of plasma antioxidant micronutrient concentrations in a representative group of patients with coronary artery disease?

Circulating antioxidant concentrations in children with inflammatory bowel disease

The mechanisms by which inflammatory bowel disease causes chronic injury to the gastrointestinal tract are poorly understood. To determine whether antioxidant defenses might be altered, we evaluated plasma antioxidant concentrations in 24 children with inflammatory bowel disease (12 with Crohn disease and 12 with ulcerative colitis) and in 23 healthy control subjects. Anthropometric measurements and disease activity scores were obtained. The groups were of similar age and sex distribution; most children had quiescent or mild disease. The children with Crohn disease were malnourished compared with the ulcerative colitis and control groups. Children with inflammatory bowel disease had decreased plasma ascorbic acid and increased glutathione peroxidase, glutathione, and alpha-tocopherol (vitamin E) concentrations compared with control subjects. These differences were found primarily in the children with Crohn disease. This study provides evidence that children with Crohn disease have alterations in circulating antioxidant defenses, possibly related to an ongoing oxidant stress.

No effect of supplementation with vitamin E, ascorbic acid, or coenzyme Q10 on oxidative DNA damage estimated by 8-oxo-7,8-dihydro-2'-deoxyguanosine excretion in smokers

The protective effect of fruit and vegetables against cancer has been related to their high antioxidant content. However, results from intervention trials have not been conclusive on the protective effect of antioxidant supplementation. In a randomized placebo-controlled trial we investigated the effect of dietary supplementation with antioxidants on a biomarker of oxidative DNA damage with mechanistic relation to carcinogenesis. One hundred forty-two smoking men aged 35-65 y were randomly assigned to one of the following seven treatments for 2 mo: 100 mg D-alpha-tocopheryl acetate plus 250 mg slow-release ascorbic acid twice a day (n = 20), 100 mg D-alpha-tocopheryl acetate twice a day (n = 20), 250 mg ascorbic acid twice a day (n = 21), 250 mg slow-release ascorbic acid twice a day (n = 21), 30 mg coenzyme Q10 in oil three times a day (n = 20), 30 mg coenzyme Q10 as granulate three times a day (n = 20), or placebo twice a day (n = 20). The trial outcome was the urinary excretion rate of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG)-a repair product of oxidative DNA damage. Two months of supplementation did not result in significant changes in the urinary excretion rate of 8-oxodG in any group. The lack of effect of antioxidant supplementation on the excretion rate of 8-oxodG, despite substantial increases in plasma antioxidant concentrations, agrees with the results from recent large intervention studies with cancer as an endpoint. The cancer-protective effect of fruit and vegetables seems to rely not on the effect of single antioxidants but rather on other anticarcinogenic compounds or on a concerted action of several micronutrients present in these foods.

Evaluation of antioxidants, protein, and lipid oxidation products in blood from sporadic amyotrophic lateral sclerosis patients.

Several parameters indicators of oxidative stress were evaluated in blood from individuals with the sporadic form of amyotrophic lateral sclerosis (SALS) and compared to healthy controls. Plasma levels of 2-thiobarbituric-reactive substances (TBARS), products of lipid peroxidation, were significantly higher (p < 0.03) in the SALS patients compared to controls. The concentration of plasma antioxidants (alpha-tocopherol, beta-carotene, ubiquinol-10 and glutathione) and the activity of red blood cell CuZn superoxide dismutase were not significantly different between the groups. The ratio TBARS/alpha-tocopherol was 47% higher in the SALS individuals than in controls. Protein thiols and protein-associated carbonyls in red blood cell membranes and supernates were similar for both groups. A positive correlation (r2 = 0.91) was found between the concentration of protein-associated carbonyls in red blood cells and the onset of clinical symptoms. These findings are in agreement with several reports showing higher levels of oxidative damage to cell components in ALS.

Plasma antioxidant concentrations in a population of elderly women: Findings from the nun study

Low plasma alpha-tocopherol and beta-carotene concentrations have been associated with an increased risk of numerous degenerative diseases, including cancer. Several characteristics that accompany aging, including changes in dietary habits and physiologic capacity, may place elderly populations at a high risk of low plasma antioxidant concentrations. Thus, the present study was undertaken to characterize plasma concentrations of alpha-tocopherol, beta-carotene and several other carotenoids in elderly subjects, to describe the relationship between age and plasma antioxidant concentrations in this population and to compare the concentrations of plasma antioxidants in middle-aged and elderly individuals. The study recruited 94 participants from the Nun Study, a longitudinal study of aging and Alzheimer disease. Women in this population were unique for their advanced age, 77–99 years old, and their comparability across age groups due to the absence of several potential confounders of plasma antioxidant concentrations. The population mean and standard deviation of several plasma carotenoids and alpha-tocopherol concentrations (μg/dl) were as follows: lycopene, 15.0+ − 10.0 ; beta-carotene, 30.0+ − 19.7 ; alpha-carotene, 15.0 + − 9.6 ; zeaxanthin plus lutein, 22.0+ − 7.4 ; beta-cryptoxanthin, 14.0 + − 8.6 and alpha-tocopherol, 980 + − 310 . Concentrations of all analytes, except lycopene, were similar to or higher than those reported for several middle-aged American populations. Lycopene concentrations were significantly lower in the population of sisters as compared with the middle-aged populations and tended to decrease across age groups within the population of sisters. Age appeared to be a relatively minor determinant of plasma alpha-tocopherol and the concentrations of carotenoids, other than lycopene, in this population. Importantly, the plasma concentrations of most carotenoids and alpha-tocopherol in this population of independent elderly women were apparently adequate on the basis of population comparisons. Further studies of this population may define determinants essential for the maintenance of antioxidant status in elderly populations.

Linoleic acid intake and susceptibility of very-low-density and low density lipoproteins to oxidation in men

Lipoprotein peroxidation is thought to play an important role in atherogenesis. In the Kuopio Atherosclerosis Prevention Study (KAPS) the intake of fat and fatty acids, the oxidation susceptibility of the plasma very-low-density + low-density lipoprotein (VLDL+LDL) fraction (by induction with copper or hemin and hydrogen peroxide), and concentrations of plasma antioxidants, serum lipids, and lipoproteins were measured in 393 men. In the multivariate-regression model dietary linoleic acid was the most important determinant of the maximal oxidation velocity for the hemin assay (standardized regression coefficient = 0.294, P<0.0001). In the copper assay the association of dietary linoleic acid and maximal oxidation velocity was second in order of strength (standardized regression coefficient = 0.324, P< 0.0001). We conclude that high linoleic acid intake is associated with increased oxidation susceptibility of atherogenic lipoproteins in men.

RRR-alpha-tocopheryl acetate supplementation at pharmacologic doses decreases low-density-lipoprotein oxidative susceptibility but not protein glycation in patients with diabetes mellitus

Patients with diabetes mellitus have an increased risk of premature atherosclerosis, which may be due in part to increased oxidizability of low-density lipoprotein (LDL). Numerous studies have shown that alpha-tocopherol can reduce the oxidative susceptibility of LDL in normoglycemic subjects; however, there are few studies in persons with diabetes. In addition, alpha-tocopherol may reduce the extent of protein glycation. Therefore, the objective of the present study was to assess the effect of RRR-alpha-tocopheryl acetate supplementation on LDL oxidizability and protein glycation in persons with diabetes without evidence of vascular disease. Twenty-eight persons with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM) were randomly assigned to receive either placebo or 1632 mg (1200 IU) RRR-alpha-tocopherol/d, as tocopheryl acetate, for 8 wk. Plasma and LDL antioxidant concentrations and LDL oxidizability were assessed at both 0 and 8 wk. Plasma and LDL concentrations of alpha-tocopherol were significantly increased in the supplemented group only. Compared with the placebo group, the alpha-tocopherol-supplemented group had significant reductions in LDL oxidizability at 8 wk, as shown by the time-course curves of conjugated diene and lipid peroxide formation. Also, alpha-tocopherol supplementation produced a significant prolongation in the lag phases of both assays, which was evident in both the NIDDM and IDDM subgroups. However, there were no significant changes in glycated hemoglobin or in glycated plasma proteins after alpha-tocopherol supplementation. Thus, alpha-tocopherol supplementation may be beneficial in reducing LDL oxidizability in patients with diabetes.