Modulation of oxidant stress in vivo in chronic cigarette smokers

Smoking and atherosclerotic cardiovascular disease: part II: role of cigarette smoking in cardiovascular disease development

Potential mechanisms and biomarkers of atherosclerosis related to cigarette smoking - a modifiable risk factor for that disease - are discussed in this article. These include smoking-associated inflammatory markers, such as leukocytes, high-sensitivity C-reactive protein, serum amyloid A, ICAM-1 and IL-6. Other reviewed markers are indicative for smoking-related impairment of arterial endothelial function (transcapillary leakage of albumin, inhibition of endogenous nitric oxide synthase activity and reduced endothelium-dependent vasodilation) or point to oxidative stress caused by various chemicals (cholesterol oxidation, autoantibodies to oxidized low-density lipoprotein, plasma levels of malondialdehyde and F(2)-isoprostanes and reduced antioxidant capacity). Smoking enhances platelet aggregability, increases blood viscosity and shifts the pro- and antithrombotic balance towards increased coagulability (e.g., fibrinogen, von Willebrand factor, ICAM-1 and P-selectin). Insulin resistance is higher in smokers compared with nonsmokers, and hemoglobin A1c is dose-dependently elevated, as is homocysteine. Smoke exposure may influence the kinetics of markers with different response to transient or chronic changes in cigarette smoking behavior.

Dietary coenzyme Q10 does not protect against cigarette smoke-augmented atherosclerosis in apoE-deficient mice

Dietary coenzyme Q10 reduces spontaneous atherosclerosis in the apoE-deficient mouse model of experimental atherosclerosis. We have shown previously that exposure to sidestream cigarette smoke (SSCS) enhances atherosclerotic lesion formation in apoE-deficient mice. The aim of the present study was to determine if CoQ10 protected against SSCS-mediated atherosclerosis. Female apoE-deficient mice were fed a saturated fat-enriched diet (SFD) alone, or supplemented with 1% wt/wt coenzyme Q10 (SFD-Q10). Mice in each diet group were exposed to SSCS for 4hrs/day, 5days/week in a whole-body exposure chamber maintained at 35+/-4mg smoke particulates/m(3). Mice kept in filtered ambient air served as controls. Mice were euthanized after either 6 or 15weeks of SSCS exposure and following measurements were performed: i) lung 7-ethoxyresorufin-O-deethylase (EROD) activity; ii) plasma cholesterol and CoQ10 concentrations; iii) aortic intimal area covered by atherosclerotic lesions; and, iv) pathological characterization of lesions. Lung EROD activity increased in SSCS mice of both diet groups, confirming SSCS exposure. Plasma concentrations of CoQ10 in SFD-Q10-fed mice were increased markedly in comparison to SFD-fed mice. Plasma cholesterol concentrations and distributions of cholesterol in lipoprotein fractions were unaffected by SSCS exposure. Dietary supplementation with CoQ10 significantly reduced atherosclerotic lesions in control mice. As reported previously, exposure to SSCS increased the size of lesions in apoE-/- mice at both time points. However, dietary supplementation with CoQ10 had no effect on atherosclerotic lesions augmented by SSCS exposure. The results suggest a role of oxidative processes in smoke-augmented atherosclerosis that are different than those mitigated by CoQ10.

No effect of 14 day consumption of whole grain diet compared to refined grain diet on antioxidant measures in healthy, young subjects: a pilot study

Background

Epidemiological evidence supports that a diet high in whole grains is associated with lowered risk of chronic diseases included coronary heart disease, obesity, type 2 diabetes, and some types of cancer. One potential mechanism for the protective properties of whole grains is their antioxidant content. The aim of this study was to compare differences in antioxidant measures when subjects consumed either refined or whole grain diets.

Methods

Twenty healthy subjects took part in a randomized, crossover dietary intervention study. Subjects consumed either a refined grain or whole grain diet for 14 days and then the other diet for the next 14 days. Male subjects consumed 8 servings of grains per day and female subjects consumed 6 servings of grains per day. Blood and urine samples were collected at the end of each diet. Antioxidant measures included oxygen radical absorbance capacity (ORAC) in blood, and isoprostanes and thiobarbituric acid reactive substances (TBARS) in urine.

Results

The whole grain diet was significantly higher in dietary fiber, vitamin B6, folate, selenium, copper, zinc, iron, magnesium and cystine compared to the refined grain diet. Despite high intakes of whole grains, no significant differences were seen in any of the antioxidant measures between the refined and whole grain diets.

Conclusions

No differences in antioxidant measures were found when subjects consumed whole grain diets compared to refined grain diets.

Regulatory factors of basal F(2)-isoprostane formation: population, age, gender and smoking habits in humans

Oxidative stress is assumed to be the key underlying factor in the pathogenesis of many common diseases. This study describes the basal levels of 8-iso-PGF(2alpha ), a major F(2)-isoprostane and an in vivo oxidative stress biomarker in healthy subjects from three countries, namely Italy, Poland and Sweden, in relation to their smoking habits, age and gender. It studied urinary 8-iso-PGF(2alpha ) in 588 subjects from Sweden (n=220), Italy (n=203) and Poland (n=165). Polish subjects had the highest levels of F(2)-isoprostanes followed by the Swedish and Italians when adjusted for smoking, age, sex and creatinine and the inter-country differences were statistically significant. Smokers had significantly higher levels of 8-iso-PGF(2alpha ) compared to non-smokers in all countries and there was a moderate decrease with age. Women had only slightly lower 8-iso-PGF(2alpha ) than men. There is a difference in F(2)-isoprostane levels in vivo between countries. Smoking, age and gender affect isoprostane formation and should be taken into consideration in clinical studies of oxidative stress.

Oxidative Stress in the Dahl Salt-Sensitive Hypertensive Rat

Oxidative stress has been proposed as important in the pathogenesis of hypertension. Measurement of 8-iso prostaglandin F2alpha (8-ISO) is introduced for evaluating oxidative stress in vivo. 8-ISO is the major urinary metabolite of F2-isoprostanes and is formed nonenzymatically from the attack of superoxide radicals on arachidonic acid. We examined the oxidative stress level in the Dahl salt-sensitive (Dahl-S) rats and the Dahl salt-resistant (Dahl-R) rats. Dahl-S and Dahl-R rats were fed either a high salt diet (8% NaCl; HS) or low salt diet (0.3% NaCl; LS) for 3 weeks, and systolic blood pressure (SBP) and 24-hr urinary excretion of 8-ISO (U-8-ISO) were measured. In Dahl-S rats, the high salt diet induced hypertension (139 +/- 3 mmHg in LS versus 186 +/- 2 mmHg in HS, p < .05) and significantly increased the U-8-ISO (24.9 +/- 3.6 ng/24 hr in LS versus 63.2 +/- 14.6 ng/24 hr in HS, p < .05). No significant difference in blood pressure or U-8-ISO was observed between high-salt and low-salt treated Dahl-R rats. U-8-ISO concentration was correlated with SBP in all four experimental groups (r = 0.866). Moreover, urinary 8-hydroxy-2'-deoxyguanosine (U-8-OHdG), which is one of the most commonly used markers for evaluation of oxidative stress, was higher in Dahl-S-8% rats than in Dahl-S-0.3% rats (136.1 +/- 48.4 ng/24 hr in LS versus 322.8 +/- 46.7 ng/24 hr in HS, p < .05), and U-8-OHdG was correlated with SBP (r = 0.681) in Dahl-S rats. These results suggest oxygen radicals are involved in the pathogenesis of hypertension.

Cigarette smoking, smoking cessation, and diabetes

There is evidence for increased risk of developing type 2 diabetes among cigarette smokers. In addition, smoking-associated health risks can exacerbate major conditions that precede or accompany diabetes, such as cardiovascular and kidney diseases. Smoking cessation can result in weight gain and a short-term worsening of some diabetic symptoms that may deter smokers with diabetes from attempting to quit. Additionally, there is limited evidence regarding the efficacy/safety of smoking cessation pharmacotherapies in this population and the general effects of smoking cessation, particularly for type 1 diabetes. Smoking cessation in diabetes therefore remains a highly relevant subject for further research.

Socioeconomic status, antioxidant micronutrients, and correlates of oxidative damage: the Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVE

To examine whether socioeconomic status (SES) (education, occupation, income), is associated both cross sectionally and prospectively with circulating concentrations of a) two correlates of oxidative damage, F(2)-isoprostanes (F(2)-IsoPs) and gamma-glutamyltransferase (GGT); and b) antioxidant nutrients (ascorbic acid and carotenoids). We also examine whether the proposed associations are mediated by smoking, alcohol consumption, and depression. Risk for chronic disease increases with decreasing SES. One pathway by which low SES might influence disease risk is by promoting oxidative stress.

METHODS

Data from 1278 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study were used to examine the association of SES with oxidation correlates and antioxidant nutrients. Education, occupation, health behaviors, and body mass index (BMI) were assessed during Years 0, 10, and 15 of the study; income and depression were evaluated at Years 10 and 15. F(2)-isoprostanes were measured at Year 15, gamma-glutamyltransferase (GGT) at Years 0 and 10, carotenoids at Years 0 and 15, and ascorbic acid at Years 10 and 15.

RESULTS

Cross sectionally, oxidation correlates decreased and antioxidant nutrients increased with increasing SES, estimated in several ways, independent of age, sex, race, and BMI. Prospectively, lower Year 0 education and occupation predicted greater increases in GGT and greater decreases in carotenoids over 10 to 15 years. Prospective associations of Year 0 SES with Year 15 carotenoids were independent of Year 15 SES. Smoking, drinking, and depression symptoms partially mediated these effects.

CONCLUSIONS

Circulating oxidation correlates increase and antioxidant nutrients decrease with decreasing SES, both cross sectionally and prospectively.

Association of oxidative stress, iron, and centralized fat mass in healthy postmenopausal women

OBJECTIVE

Centralized adiposity, insulin resistance, excess iron, and elevated oxidative stress place postmenopausal women at risk for atherosclerotic cardiovascular disease (CVD). The objective of this study was to determine the relationship among excess iron, oxidative stress, and centralized fat mass in healthy postmenopausal women.

METHODS

The parent project recruited healthy women for a randomized, double-blind, clinical trial designed to examine the effect of soy isoflavones on bone. At baseline (n = 122), we measured three antioxidant enzymes, iron status indices (serum ferritin among others), oxidative stress indices (oxidized low-density lipoprotein [oxLDL], urinary isoprostanes [PGF(2alpha)], protein carbonyls, DNA damage), and waist, hip, and thigh fat mass using dual-energy x-ray absorptiometry (DXA). We calculated insulin resistance using the homeostasis model assessment (HOMA). Multiple regression analysis was used to determine the CVD risk factors that contributed to oxidative stress and centralized fat mass (waist + hip/thigh = AndGynFM ratio).

RESULTS

Almost 14% (p < 0.0005) of the variability in oxLDL was accounted for by AndGynFM ratio (6.1%, p < 0.0005), age (4.0%, p = 0.012), and serum iron (2.8%, p = 0.053). Similarly, 16% (p < 0.0001) of the variability in PGF(2alpha) was accounted for by the AndGynFM ratio (4.8%, p = 0.011), HOMA (3.9%, p = 0.021), and serum iron (2.7%, p = 0.054). We accounted for 33% (p

CONCLUSIONS

Our study suggests that reducing centralized fat mass and maintaining a favorable lipid profile, antioxidant status, and iron status all may be important in protecting postmenopausal women from atherosclerotic CVD.

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Key Words Collapse

MESH Headings

• Aged
• Biomarkers/blood
• Body Fat Distribution/adverse effects
• Body Mass Index
• Bone Density/drug effects
• Bone and Bones/drug effects
• Coronary Artery Disease/blood
• Coronary Artery Disease/etiology
• Coronary Artery Disease/prevention & control
• Double-Blind Method
• Female
• Ferritins/blood
• Folic Acid/blood
• Humans
• Iron/metabolism
• Middle Aged
• Oxidative Stress/drug effects
• Postmenopause/blood
• Reference Values
• Soybean Proteins/administration & dosage
• Soybean Proteins/pharmacology
• Waist-Hip Ratio

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Grants

• R01 AR046922-01A2 NIAMS NIH HHS
• R01 AR046922 A2 NIAMS NIH HHS
• P01 ES012020 NIEHS NIH HHS
• 95P50AT004155 NCCIH NIH HHS

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Affiliation(s)

Betsy L. Crist Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
D. Lee Alekel Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa Nutrition and Wellness Research Center, Iowa State University, Ames, Iowa
Laura M. Ritland Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
Laura N. Hanson Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
Ulrike Genschel Department of Statistics, Iowa State University, Ames, Iowa
Manju B. Reddy Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa

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Endothelial dysfunction and cardiovascular risk factors

The endothelium plays an integral role in the regulation of vascular tone, platelet activity, leukocyte adhesion, and thrombosis and is intimately involved in the development of atherosclerosis. Endothelial dysfunction has been observed in patients with established coronary artery disease or coronary risk factors, both in the coronary and peripheral vasculature. Therapeutic interventions with lipid-lowering drugs, ACE inhibitors, physical activity, and antioxidant agents have been shown to improve endothelial function in coronary and peripheral vessels. This systemic manifestation and improvement of endothelial function suggests that a common mechanism may contribute to endothelial dysfunction in the coronary and peripheral circulation.

TARGET AUDIENCE

Internist, Cardiologists, Family physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to define the participation of cardiovascular risk factors in the various complications associated with endothelial dysfunction.

Plasma Carotenoids and Biomarkers of Oxidative Stress in Patients with prior Head and Neck Cancer

Diets high in fruits and vegetables are generally believed protective against several chronic diseases. One suggested mechanism is a reduction in oxidative stress. The carotenoids, nutrients found in colored fruits and vegetables, possess antioxidant properties in vitro, but their role in humans is less well documented. The aim of this cross-sectional study was to explore the relationships between the most abundant plasma carotenoids (alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin and beta-cryptoxanthin), as well as grouped carotenoids (total xanthophylls, carotenes and carotenoids), and urinary excretion of the F(2)-isoprostanes (F(2)-IsoPs), stable and specific biomarkers of oxidative damage to lipids. Two F(2)-IsoP measures were utilized: total F(2)-IsoPs and 8-iso-PGF(2alpha). The study population (N = 52) was drawn from a study among patients curatively treated for early-stage head and neck cancer. Unadjusted linear regression analyses revealed significant inverse associations between plasma lutein, total xanthophylls and both F(2)-IsoP measures at baseline. After control for potential confounders, all individual and grouped xanthophylls remained inversely associated with the F(2)-IsoP measures, but none of these associations achieved significance. The carotenes were not inversely associated with total F(2)-IsoPs or 8-iso-PGF(2a) concentrations. The finding of consistent inverse associations between individual and grouped xanthophylls, but not individual and grouped carotenes, and F(2)-IsoPs is intriguing and warrants further investigation.

The association between cigarette smoking and carotid intima-media thickness is influenced by the -930A/G CYBA gene polymorphism: the Cardiovascular Risk in Young Finns Study

BACKGROUND

Smoking-induced damage to the cardiovascular system has been shown in many studies; however, the degree of damage varies from individual to individual. We hypothesized that the -930A/G CYBA gene polymorphism in the NADPH oxidase influences the association between cigarette smoking and carotid intima-media thickness (IMT) in young healthy adults.

METHODS

Cross-sectional data obtained in 2001 for the Cardiovascular Risk in Young Finns Study were used. IMT was measured with ultrasound. The genotyping was performed using a 5'-nuclease assay. A linear regression model was used to test whether the interaction between smoking and the genotypes was associated with IMT. The magnitude of the interaction effect was further examined by performing a stratified analysis according to smoking habits.

RESULTS

In the entire population, the mean and maxima IMT were higher in smokers than nonsmokers (P = 0.005 and 0.008, respectively). The differences were most significant in subjects with the GG genotype, borderline significant for the GA genotype, and nonsignificant for the AA genotype. The interaction of genotypes with smoking was associated with mean and maximal IMT (P = 0.042 and 0.022). Among smokers, subjects with the GG genotype had a higher mean and maximal IMT compared with carriers of the A allele (P = 0.021 and 0.012). In contrast, the mean and maximal IMT were lower for G allele carriers than subjects with the AA genotype among nonsmokers (P = 0.022 and 0.026). All results had been adjusted for potential risk factors related to IMT.

CONCLUSION

The -930A/G polymorphism modifies the association between cigarette smoking and IMT in young healthy adults.

Oxidative stress biomarkers and lifestyles in Japanese healthy people

The urinary concentrations of 8-isoprostane and 8-hydroxy-2’-deoxyguanosine (8-OHdG), which are biomarkers of oxidative stress, were measured in 677 Japanese people without any diseases, and their correlations with lifestyle facotrs, lifestyle-related blood biochemical parameters, and dietary intake of antioxidative vitamins were investigated. The mean urinary concentration of 8-isoprostane and 8-OHdG was 0.58 ng/mg creatinine and 8.43 ng/mg creatinine, respectively. Mean urinary 8-isoprostane was significantly different in terms of age, gender, smoking and alcohol consumption but not different in terms of body mass index (BMI) and exercise. By multiple regression analysis, urinary 8-isoprostane was significantly influenced by smoking and age. On the other hand, mean urinary 8-OHdG showed differences only by age group. Multiple regression analysis revealed that urinary 8-OHdG was significantly influenced by age, smoking, body weight, levels of high-sensitivity C-reactive protein (Hs-CRP) and low density lipoprotein-cholesterol in females, although it was significantly influenced by body weight in males. The present study shows that urinary 8-isoprostane is associated with lipid peroxidation related-lifestyles such as smoking, and urinary 8-OHdG is associated with arteriosclerosis related-factors such as Hs-CRP. Our findings suggest that 8-isoprostane and 8-OHdG appear to be prospective biomarkers for early prediction of lifestyle related-disease risk at the population level.

Clinical implications of endothelial dysfunction

Endothelial dysfunction is increasingly recognized as an early event in the pathogenesis of cardiovascular disease. This observation is consistent with the growing appreciation of the role of endothelium in maintaining cardiovascular health. Endothelial dysfunction and coronary artery disease are both linked to hypertension, hypercholesterolemia, diabetes mellitus, and cigarette smoking. Modification of these conditions improves both endothelial function and coronary artery disease outcomes. Dietary and lifestyle modifications and antioxidant vitamin supplementation have a beneficial effect on endothelial function, as do angiotensin-converting enzyme inhibitors and lipid-lowering agents. Future studies will determine whether interventions that specifically target endothelial dysfunction can reduce rates of clinical disease.

Compartmental analysis of plasma and liver n-3 essential fatty acids in alcohol-dependent men during withdrawal

The mechanism by which chronic ethanol consumption reduces concentrations of long chain polyunsaturated (LCP) fatty acids (FA) in tissues of humans was investigated in alcohol-dependent (AD) men during early withdrawal and to a well-matched control group by fitting the concentration-time curves of d(5)-labeled n-3 FA from plasma and liver, which originated from an oral dose of d(5)-linolenic acid (d(5)-18:3n-3) ethyl ester to a compartmental model. Blood sampled over 168 h and a liver specimen obtained 96 h after isotope administration were analyzed for d(5)-18:3n-3, d(5)-20:5n-3, d(5)-22:5n-3, and d(5)-22:6n-3. Plasma 20:5n-3 and 22:5n-3 were lower in AD subjects, compared with controls (20:5n-3: -50%, 22:5n-3: -34%). Increased amounts of d(5)-18:3n-3 were directed toward synthesis of d(5)-20:5n-3 in AD subjects (P < .05). However, this effect was offset by larger amounts of 20:5n-3 lost from plasma (control: 2.0 vs. AD: 4.2 mg d(-1)). In livers of AD subjects, more d(5)-18:3n-3 and d(5)-22:5n-3 were utilized for synthesis of d(5)-20:5n-3 (+200%) and d(5)-22:6n-3 (+210%), respectively, than was predicted from plasma kinetics. Although, the potential to utilize linolenic acid for synthesis of LCP FA was greater in AD subjects compared with controls, heightened disappearance rates of 20:5n-3 reduced overall plasma concentrations of several endogenous n-3 LCP FA.

Vitamins C and E and beta carotene supplementation and cancer risk: a randomized controlled trial

BACKGROUND

Observational studies suggested that a diet high in fruits and vegetables, both of which are rich with antioxidants, may prevent cancer development. However, findings from randomized trials of the association between antioxidant use and cancer risk have been mostly negative.

METHODS

From 8171 women who were randomly assigned in the Women's Antioxidant Cardiovascular Study, a double-blind, placebo-controlled 2 x 2 x 2 factorial trial of vitamin C (500 mg of ascorbic acid daily), natural-source vitamin E (600 IU of alpha-tocopherol every other day), and beta carotene (50 mg every other day), 7627 women who were free of cancer before random assignment were selected for this study. Diagnoses and deaths from cancer at a specific site were confirmed by use of hospital reports and the National Death Index. Cox proportional hazards regression models were used to assess hazard ratios (represented as relative risks [RRs]) of common cancers associated with use of antioxidants, either individually or in combination. Subgroup analyses were conducted to determine if duration of use modified the association of supplement use with cancer risk. All statistical tests were two-sided.

RESULTS

During an average 9.4 years of treatment, 624 women developed incident invasive cancer and 176 women died from cancer. There were no statistically significant effects of use of any antioxidant on total cancer incidence. Compared with the placebo group, the RRs were 1.11 (95% confidence interval [CI] = 0.95 to 1.30) in the vitamin C group, 0.93 (95% CI = 0.79 to 1.09) in the vitamin E group, and 1.00 (95% CI = 0.85 to 1.17) in the beta carotene group. Similarly, no effects of these antioxidants were observed on cancer mortality. Compared with the placebo group, the RRs were 1.28 (95% CI = 0.95 to 1.73) in the vitamin C group, 0.87 (95% CI = 0.65 to 1.17) in the vitamin E group, and 0.84 (95% CI = 0.62 to 1.13) in the beta carotene group. Duration and combined use of the three antioxidants also had no effect on cancer incidence and cancer death.

CONCLUSIONS

Supplementation with vitamin C, vitamin E, or beta carotene offers no overall benefits in the primary prevention of total cancer incidence or cancer mortality.

Low dietary intake of β-carotene, α-tocopherol and ascorbic acid is associated with increased inflammatory and oxidative stress status in a Swedish cohort

Fruit and vegetable consumption has been associated with a reduced risk of several diseases including CVD. A part of these effects seen could be linked to anti-inflammatory and antioxidative effects, although this has not been thoroughly investigated. The present study was designed to investigate the effects of the dietary intake of β-carotene, α-tocopherol and ascorbic acid on in vivo biomarkers of inflammation (PGF2α, high-sensitive C-reactive protein (hsCRP) and IL-6 formation) and oxidative stress (F2-isoprostane formation), the two important factors associated with accelerated atherosclerosis. The dietary intake of 704 participants in the Uppsala Longitudinal Study of Adult Men (ULSAM) at age 70 years was registered and inflammatory and oxidative stress biomarkers were quantified 7 years later. The registered dietary intakes of ascorbic acid and α-tocopherol were negatively associated linearly and in quartiles with both PGF2α, hsCRP, IL-6 and F2-isoprostanes, where ascorbic acid intake generally was more strongly associated. Dietary intake of β-carotene was only significantly negatively associated with F2-isoprostanes. In conclusion, the present study is the first to suggest that the intake of food rich in antioxidants is associated with reduced cyclo-oxygenase- and cytokine-mediated inflammation and oxidative stress at 7 years of follow-up. These associations could be linked to the beneficial effects of fruit and vegetables observed on CVD.

Increased plasma levels of 8-iso-PGF2alpha and IL-6 in an elderly population with depression

Oxidative damage and immune-inflammatory activation have been suggested to play a role in depression. The purpose of the study was to investigate possible associations and interactions of these pathophysiological mechanisms in geriatric depression by determining the levels of plasma 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) and interleukin-6 (IL-6) in elderly depressed individuals. Subjects over 60 years of age with depression and controls were randomly selected from a population in the community after screening with the Geriatric Depression Scale. Plasma concentrations of 8-iso-PGF2alpha and IL-6 were measured in both groups. Depressed patients had significantly higher mean (+/-S.D.) 8-iso-PGF2alpha levels compared to healthy controls (245.01+/-179.92 pg/ml vs 97.64+/-42.72 pg/ml, respectively). Similarly, the same groups demonstrated significantly elevated IL-6 levels compared with controls (58.73+/-39.90 pg/ml vs 15.41+/-9.27 pg/ml). This study indicates an association between increased levels of plasma 8-iso-PGF2alpha and IL-6 with depressive symptomatology in elderly individuals and indicates the necessity for further investigation, possibly within the framework of an integrated involvement of oxidative damage and inflammation in the pathophysiology of depression in the elderly.

Oxidative Stress as a Mechanism of Valproic Acid-Associated Hepatotoxicity

Valproic acid (2-n-propylpentanoic acid; VPA) has several therapeutic indications, but it is used primarily as an anticonvulsant. VPA is a relatively safe drug, but its use is associated with idiosyncratic hepatotoxicity, which in some cases may lead to fatality. The underlying mechanism responsible for the hepatotoxicity is still not well understood, but various hypotheses have been proposed, including oxidative stress. This article discusses the experimental evidence on the effect of VPA on the various indices of oxidative stress and on the potential role of oxidative stress in VPA-associated hepatotoxicity.

Fibrinogen beta-chain tyrosine nitration is a prothrombotic risk factor

Elevated levels of circulating fibrinogen are associated with an increased risk of atherothrombotic diseases although a causative correlation between high levels of fibrinogen and cardiovascular complications has not been established. We hypothesized that a potential mechanism for an increased prothrombotic state is the post-translational modification of fibrinogen by tyrosine nitration. Mass spectrometry identified tyrosine residues 292 and 422 at the carboxyl terminus of the beta-chain as the principal sites of fibrinogen nitration in vivo. Immunoelectron microscopy confirmed the incorporation of nitrated fibrinogen molecules in fibrin fibers. The nitration of fibrinogen in vivo resulted in four distinct functional consequences: increased initial velocity of fibrin clot formation, altered fibrin clot architecture, increased fibrin clot stiffness, and reduced rate of clot lysis. The rate of fibrin clot formation and clot architecture was restored upon depletion of the tyrosine-nitrated fibrinogen molecules. An enhanced response to the knob "B" mimetic peptides Gly-His-Arg-Pro(am) and Ala-His-Arg-Pro(am) suggests that incorporation of nitrated fibrinogen molecules accelerates fibrin lateral aggregation. The data provide a novel biochemical risk factor that could explain epidemiological associations of oxidative stress and inflammation with thrombotic complications.

Key issues in F2-isoprostane analysis

A large body of evidence indicates that measurement of F2-isoprostanes, specific prostaglandin F2-like compounds derived from the non-enzymatic peroxidation of arachidonic acid, is a reliable biomarker of oxidant stress in the human body. Since the discovery of F2-isoprostanes in the early 1990s, a variety of analytical approaches has been introduced for the quantification of these novel compounds. The aim of the present review is to shed light on the available gas chromatographic–mass spectrometric assays for the measurement of plasma or urinary F2-isoprostanes and to highlight a number of issues which need to be addressed in order to implement F2-isoprostane measurement as a gold-standard biomarker of oxidative stress in biological samples.

Beyond prostaglandins--chemistry and biology of cyclic oxygenated metabolites formed by free-radical pathways from polyunsaturated fatty acids

Polyunsaturated fatty acids (PUFAs) are important constituents in all organisms. They fulfil many functions, ranging from modulating the structure of membranes to acting as precursors of physiologically important molecules, such as the prostaglandins, which for a long time were the most prominent cyclic PUFA metabolites. However, since the beginning of the 1990s a large variety of cyclic metabolites have been discovered that form under autoxidative conditions in vivo to a much larger extent than do prostaglandins. These compounds--isoprostanes, neuroprostanes, phytoprostanes, and isofurans--proved subsequently to be ubiquitous in nature. They display a wide range of biological activities, and isoprostanes have become the currently most reliable indicators of oxidative stress in humans. In a relatively short time, the structural variety, properties, and applications of the autoxidatively formed cyclic PUFA derivatives have been uncovered.

Pampiniform plexus and oxidative stress during chronic hypoxia and hyperoxia

The aim of the present study is to investigate oxidative stress produced by experimental hypoxia and hyperoxia in young and old pampiniform plexus rats, in order to evaluate the oxidative role of oxygen. Oxidative stress causing molecular and cellular dysfunction increases in hypertension and can therefore be considered a state of oxidative stress. This consideration makes us reflect on the responsibility of oxidative stress in the veins of the pampiniform plexus, notoriously under high hydrostatic pressure. After experimental hypoxia and hyperoxia we studied the 8-iso-PGF2alpha release (a specific index of cellular oxidative stress) in young and old left pampiniform plexus rats. The basal 8-iso-PGF2alpha release showed a statistically significant difference P=0.0067 between young and old rats PP. After hypoxia and hyperoxia, the release was higher in young rats as compared to normoxia, respectively P=0.0001 and P=0.0002. After hypoxia the release was not modified in old rats P=0.544 while after hyperoxia the release was increased in old rats as compared to control P less than 0.0001. The results show how chronic hypoxia and hyperoxia represent two important causes of oxidative stress and lipid peroxidation in pampiniform plexus rats. In young rats an increase of oxidative stress suggests that pampiniform plexus is sensitive to variations of oxygen supply. In old rats the pampiniform plexus is liable to a reduction of oxygen-sensing mechanisms and it is possible that the missing oxidative answer to the hypoxia in old rats is attributable in all likelihood to adaptation to a hypoxic condition typical of aging.

Women and smokers have elevated urinary F(2)-isoprostane metabolites: a novel extraction and LC-MS methodology

F(2)-Isoprostanes (F(2)-IsoPs), regio- and stereoisomers of prostaglandin F(2alpha) (PGF(2alpha)), and urinary F(2)-IsoP metabolites including 2,3-dinor-5,6-dihydro-8-iso-PGF(2alpha) [2,3-dinor-8-iso-PGF(1alpha) (2,3-dinor-F1)] and 2,3 dinor-8-iso-PGF(2alpha) (2,3-dinor-F2), have all been used as biomarkers of oxidative stress. A novel method was developed to measure these biomarkers using a single solid phase extraction (SPE) cartridge, separation by HPLC, and detection by negative mode selected reaction monitoring (SRM) mass spectrometry (MS), using authentic standards of PGF(2alpha); 8-iso-PGF(2alpha); 2,3-dinor-F1 and 2,3-dinor-F2 to identify specific chromatographic peaks. The method was validated in a population of healthy, college-aged nonsmokers (n = 6 M/8F) and smokers (n = 6 M/5F). Urinary F(2)-IsoP concentrations were approximately 0.2-1.5 microg/g creatinine, 2,3-dinor-F1 was approximately1-3 microg/g and 2,3-dinor-F2 was approximately 3-5 microg/g. Additional F(2)-IsoPs metabolites were identified using SRM. The sum of all urinary F(2)-IsoP metabolites was 50-100 microg/g creatinine indicating their greater abundance than F(2)-IsoPs. Women had higher F(2)-IsoP metabolite concentrations than did men (MANOVA, main effect P = 0.003); cigarette smokers had higher concentrations than did nonsmokers (main effect P = 0.036). For men or women, respectively, smokers had higher metabolite concentrations than did nonsmokers (P < 0.05). Thus, our method simultaneously allows measurement of urinary F(2)-IsoPs and their metabolites for the determination of oxidative stress.

Markers of oxidative stress and systemic vasoconstriction in pregnant women drinking > or =48 g of alcohol per day

BACKGROUND

The precise pathway by which alcohol causes the characteristic features of fetal alcohol spectrum disorders is unknown. Proposed mechanisms for fetal injury from maternal alcohol use include cellular damage from oxidative stress and impaired fetal oxygenation related to maternal systemic vasoconstriction. Our objective was to compare the levels of urinary markers of oxidative stress and systemic vasoconstriction between women consuming large amounts of alcohol during pregnancy and women who did not drink alcohol during pregnancy.

METHODS

Pregnant women consuming > or =48 g alcohol per day (n = 29) on average and pregnant women who abstained from alcohol use (n = 39) were identified using detailed interviews and home visits. Random maternal urine specimens were collected. Urinary levels of the oxidative stress marker, 8-isoprostane F2alpha, and of the vasoactive prostaglandin metabolites, 2,3-dinor-6-keto-prostaglandin F1alpha (a vasodilator) and 11-dehydro-thromboxane B2 (a vasoconstrictor), were measured using mass spectrometric methods. All analyte levels were corrected for urinary creatinine.

RESULTS

In crude analyses, there was no significant difference in 8-isoprostane F2alpha between pregnant drinkers and nondrinkers (2.16 vs. 2.08 ng/mg creatinine, respectively, p = 0.87). There were no significant differences between the drinking and nondrinking groups in levels of 2,3-dinor-6-keto-prostaglandin F1alpha (1.03 vs. 1.17 ng/mg creatinine, respectively, p = 0.50), 11-dehydro-thromboxane B2 (0.72 vs. 0.59 ng/mg creatinine, respectively, p = 0.21), or the ratio of vasodilatory metabolite to vasoconstrictive metabolite (1.73 vs. 2.72, respectively, p = 0.14). Adjusting for maternal age, marital status, smoking, and gestational age at sampling did not substantially alter the results.

CONCLUSION

Our results show no difference in levels of urinary eicosanoid markers of oxidative stress and systemic vasoconstriction between pregnant women who drink heavily and pregnant women who abstain. These findings speak against a role for maternal oxidative stress or systemic vasoconstriction in the pathogenesis of alcohol damage to the fetus.

Plasma carbonyls do not correlate with lung function or computed tomography measures of lung density in older smokers

Oxidative stress and inflammation are hallmarks of chronic obstructive pulmonary disease (COPD). A critical byproduct of oxidative damage is the introduction of carbonyl groups into amino acid residues. We hypothesize that plasma carbonyl content is inversely correlated with lung function and computed tomography (CT) measures of lung density among smokers and is elevated in COPD. Carbonyl was measured in plasma of participants aged 60 years and older by ELISA. Generalized linear and additive models were used to adjust for potential confounders. Among 541 participants (52% male, mean age 67 years, 41% current smokers), mean plasma carbonyl content was 17.9+/-2.9 nmol ml(-1) and mean forced expiratory volume in one second (FEV(1)) was 80.7+/-20.9% of predicted. Plasma carbonyl content was inversely associated with FEV(1), but this relationship was largely explained by age. Multivariate analyses ruled out clinically meaningful associations of plasma carbonyl content with FEV(1), FEV(1)/FVC (forced vital capacity) ratio, severity of airflow obstruction, and CT lung density. Plasma carbonyl content is a poor biomarker of oxidative stress in COPD and emphysema.

F2-isoprostanes in human health and diseases: from molecular mechanisms to clinical implications

Oxidative stress is implicated as one of the major underlying mechanisms behind many acute and chronic diseases, and involved in normal aging. However, the measurement of free radicals or their end products is complicated. Thus, proof of association of free radicals in pathologic conditions has been absent. Isoprostanes are prostaglandin-like bioactive compounds that are biosynthesized in vivo independent of cyclooxygenases, principally through free-radical catalyzation of arachidonic acid. Isoprostanes are now considered to be reliable biomarkers of oxidative stress, as evidenced by an autonomous study organized recently by the National Institutes of Health (NIH) in the United States. A number of these compounds have potent biologic activities such as vasoconstrictive and certain inflammatory properties. Isoprostanes are involved in many human diseases. Additionally, elevated levels of F(2)-isoprostanes have been seen in normal human pregnancy and after intake of some fatty acids, but their physiologic assignments have not yet been distinctive. This evidence indicates that measurement of bioactive F(2)-isoprostanes in body fluids offers a unique noninvasive analytic utensil to study the role of free radicals in physiology, oxidative stress-related diseases, experimental acute or chronic inflammatory conditions, and also in the assessment of various antioxidants, radical scavengers, and drugs.

Environmental risk factors for heart disease

In this review, we discuss current evidence linking environmental pollutants to cardiovascular disease (CVD). Extensive evidence indicates that environmental factors contribute to CVD risk, incidence, and severity. Migrant studies show that changes in the environment could substantially alter CVD risk in a genetically stable population. Additionally, CVD risk is affected by changes in nutritional and lifestyle choices. Recent studies in the field of environmental cardiology suggest that environmental toxins also influence CVD. Exposure to tobacco smoke is paradigmatic of such environmental risk and is strongly and positively associated with increased cardiovascular morbidity and mortality. In animal models of exposure, tobacco smoke induces endothelial dysfunction and prothrombotic responses and exacerbates atherogenesis and myocardial ischemic injury. Similar mechanism may be engaged by other pollutants or food constituents. Several large population-based studies indicate that exposure to fine or ultrafine particulate air pollution increases CVD morbidity and mortality, and the plausibility of this association is supported by data from animal studies. Exposure to other chemicals such as polyaromatic hydrocarbons, aldehydes, and metals has also been reported to elevate CVD risk by affecting atherogenesis, thrombosis, or blood pressure regulation. Maternal exposure to drugs, toxins, and infection has been linked with cardiac birth defects and premature CVD in later life. Collectively, the data support the notion that chronic environmental stress is an important determinant of CVD risk. Further work is required to assess the magnitude of this risk fully and to delineate specific mechanisms by which environmental toxins affect CVD.

The role of aspirin in cardiovascular prevention: implications of aspirin resistance

Aspirin is well recognized as an effective antiplatelet drug for secondary prevention in subjects at high risk of cardiovascular events. However, most patients receiving long-term aspirin therapy still remain at substantial risk of thrombotic events due to insufficient inhibition of platelets, specifically via the thromboxane A2 pathway. Although the exact prevalence is unknown, estimates suggest that between 5.5% and 60% of patients using this drug may exhibit a degree of "aspirin resistance," depending upon the definition used and parameters measured. To date, only a limited number of clinical studies have convincingly investigated the importance of aspirin resistance. Of these, few are of a sufficient scale, well designed, and prospective, with aspirin used at standard doses. Also, most studies do not sufficiently address the issue of noncompliance to aspirin as a frequent, yet easily preventable cause of resistance to this antiplatelet drug. This review article provides a comprehensive overview of aspirin resistance, discussing its definition, prevalence, diagnosis, and therapeutic approaches. Moreover, the clinical implications of aspirin resistance are explored in various cardiovascular disease states, including diabetes mellitus, hypertension, heart failure, and other similar disorders where platelet reactivity is enhanced.

The influence of pravastatin and atorvastatin on markers of oxidative stress in hypercholesterolemic humans

OBJECTIVES

The aim of this study was to determine the effects of pravastatin and atorvastatin on markers of oxidative stress in plasma.

BACKGROUND

Hydroxymethylglutaryl coenzyme A reductase inhibitors reduce low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk, but their effects on circulating biomarkers of oxidative stress are not well-defined.

METHODS

Hypercholesterolemic subjects (n = 120, ages 21 to 80 years with LDL-C 130 to 220 mg/dl) were randomized in a double-blind, parallel design to pravastatin 40 mg/day (prava40), atorvastatin 10 mg/day (atorva10), atorvastatin 80 mg/day (atorva80), or placebo. At baseline and 16 weeks, urinary isoprostanes (8, 12-iso-iPF(2 alpha)-VI isoform), plasma lipoprotein-associated phospholipase A2 (Lp-PLA2), Mercodia oxidized LDL (OxLDL) with antibody 4E6, oxidized phospholipids/apolipoprotein B-100 particle (OxPL/apoB) with antibody E06, immunoglobulin (Ig)G/IgM autoantibodies to malondialdehyde (MDA)-LDL, and apolipoprotein B (apoB)-immune complexes (IC) were measured.

RESULTS

After 16 weeks, there were no significant changes in urinary 8, 12-iso-iPF(2 alpha)-VI. The Lp-PLA2 and OxLDL were reduced in statin-treated groups, but after adjusting for apoB, only prava40 led to a reduction in Lp-PLA2 (-15%, p = 0.008) and atorva10 to a decrease in OxLDL (-12.9%, p = 0.01). The OxPL/apoB increased 25.8% (p < 0.01) with prava40 and 20.2% (p < 0.05) with atorva80. There were no changes in MDA-LDL autoantibodies, but significant decreases in IC were noted.

CONCLUSIONS

This study suggests that statin therapy results in variable effects on oxidative stress markers in hypercholesterolemic subjects. Future outcome studies should collectively assess various oxidative markers to define clinical utility.

Oestrogen metabolites in relation to isoprostanes as a measure of oxidative stress

OBJECTIVE

Oestradiol (E2) and its metabolites 2-hydroxyoestrone (2-OHE1) and 16alpha-hydroxyoestrone (16alpha-OHE1) are thought to curtail the greater oxidative stress found in the development and progression of disease conditions including atherosclerosis. We related oestrogen levels to F(2a)-isoprostane levels, a biomarker of oxidative stress.

DESIGN AND PARTICIPANTS

Data were obtained from 1647 women, aged 47-57 years, participating in the fifth annual follow-up of the Study of Women's Health Across the Nation (SWAN), a study of the menopausal transition.

MEASUREMENTS

Serum E2 and urinary 2-OHE1 and 16alpha-OHE1 concentrations were determined by enzyme-linked immunosorbent assay (ELISA) and urinary F(2a)-isoprostanes were measured by enzyme immunoassay (EIA).

RESULTS

F(2a)-isoprostane concentrations were elevated in women who smoked, a behaviour associated with increased oxidative stress, but not in stages of the natural menopause. Mean F(2a)-isoprostane concentrations among pre- and postmenopausal women who smoked were 1082 and 1064 pg/ml, respectively, values double those in pre- (343 pg/ml) and postmenopausal (379 pg/ml) nonsmoking women. 2-OHE1 and F(2a)-isoprostane concentrations were positively and highly correlated (partial correlations rho(Y|X) = 0.44 and rho(Y|X) = 0.43 in pre- and postmenopausal women, respectively). Similarly, 16alpha-OHE1 concentrations were positively and highly correlated with F(2a)-isoprostane concentrations (rho(Y|X) = 0.52 and rho(Y|X) = 0.59 in pre- and postmenopausal women, respectively). E2 was significantly correlated with F(2a)-isoprostanes only in postmenopausal women (rho(Y|X) = 0.20). Associations were adjusted for age, body mass index (BMI), race/ethnicity, lipids, physical activity level and alcohol consumption.

CONCLUSIONS

This study does not support the commonly held hypothesis that levels of endogenous E2 or its oestrone metabolites favourably modify oxidative stress by decreasing F2(a)-isoprostane levels.

Associations of serum carotenoid concentrations with the metabolic syndrome: interaction with smoking

Recent epidemiological studies show the associations of serum antioxidant status with the metabolic syndrome. Oxidative stress may play an important role in the pathogenesis of diabetes and CVD. Actually, smoking is a potent oxidative stressor in man, but little is known about the interaction of serum carotenoids and the metabolic syndrome with smoking status. In this study, the associations of the serum carotenoids with the metabolic syndrome stratified by smoking habit were evaluated cross-sectionally. A total of 1073 subjects (357 male and 716 female) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Among total subjects, the OR for the metabolic syndrome in the highest tertile of serum beta-carotene was 0.41 (95 % CI 0.18, 0.92) after adjusting confounders. In current smokers, significantly lower OR were observed in the middle (OR 0.10; 95 % CI 0.01, 0.72) and highest (OR 0.06; 95 % CI 0.01, 0.73) tertiles of serum beta-carotene. Furthermore, lower OR were observed in accordance with tertiles of serum alpha-carotene and beta-cryptoxanthin in current smokers (P for trend 0.042 and 0.036, respectively). In contrast, in non-smokers, a significantly lower OR was observed in the highest tertile of serum beta-carotene (OR 0.30; 95 % CI 0.10, 0.89) after multiple adjustment. Inverse associations of serum carotenoids with the metabolic syndrome were more evident among current smokers than non-smokers. These results support that antioxidant carotenoids may have a protective effect against development of the metabolic syndrome, especially in current smokers who are exposed to a potent oxidative stress.

Influence of smoking during pregnancy on haemostasis in healthy full term neonates

BACKGROUND

Clinical and experimental researches have linked smoking to disturbances of coagulation and fibrinolysis. Several potential mechanisms are incriminated involving inflammation, fibrinogen synthesis and clotting factors. Based on the fact that the majority of tobacco components cross the placental barrier, the objective of our current study is to investigate the influence of smoking during pregnancy on neonatal haemostasis.

STUDY DESIGN

The study was based on a comparative evaluation of coagulation and fibronolysis between healthy full term infants of women who smoked during pregnancy and a control group. Subjects consisted of 39 newborns of smoking and 43 newborns of nonsmoking mothers. Blood samples were obtained shortly after birth and before the administration of vitamin K. Investigation included: PT, INR, aPTT, fibrinogen, coagulation factors II, V, VII, VIII, IX, X, XI, XII, vWillebrand (vWF), protein C and S, APCr, anti-thrombin (AT), t-PA and PAI-1. The independent t- test was used to compare the differences between the values of coagulation and fibrinolytic parameters at the p<0.05 level.

RESULTS

We discovered a statistically significant decrease in factor II and protein S levels and an elevation in t-PA and factor VIII concentrations in newborns of smoking mothers, without clinical manifestations of altered haemostasis. There were no significant differentiations in other coagulation or fibrinolytic parameters.

CONCLUSION

The alteration in factor II, protein S, t-PA and factor VIII in neonates exposed in utero to tobacco smoke is not accompanied by loss in the balance between coagulation and fibrinolytic pathways.

Supplement use and mortality: the SENECA study

BACKGROUND

It is hypothesis that in relatively healthy older people supplement usage can be consider as healthy life style habit and as such can positively influence longevity.

AIM OF THE STUDY

To determine whether supplement use was associated with all-cause mortality in the participants of the SENECA study.

METHODS

Baseline measurements were carried out in 1988/1989 among 75 to 80-year-old people living in 15 European small towns. All-cause mortality was followed up to April 30, 1999. Data from 920 men and 980 women who were ischemic heart diseases-, stroke- and cancer-free at baseline were included. The multivariate adjusted (for sex, age, years of education, physical activity, BMI, chronic diseases, Mediterranean Diet Score, alcohol use and the place of living) hazard ratio (HRs) and 95% confidence intervals (CIs) of mortality by use of any type of nutrient supplement and by particular nutrient supplement use were estimated by Cox proportional hazards regression models.

RESULTS

At baseline, 13% of participants used nutritional supplements, 19% of subjects were smokers. During 10 years of follow-up 445 men and 252 women died. Among non-smokers no significant associations between total supplement use and particular nutrient supplement use were observed. Among smokers use of any type of supplements (Multivariate HR: 1.52; 95%CI: 1.02-2.28), use of vitamin B(1) (Multivariate HR: 1.57; 95%CI: 1.00-2.48) and vitamin B(2) supplements (Multivariate HR: 1.60; 95%CI: 1.00-2.56) were associated with a significantly higher risk of all-cause mortality. The similar tendencies were observed among vitamin B(6) and vitamin C supplement users who were smokers.

CONCLUSIONS

Among smokers, participants of the SENECA study, supplement use increased all-cause mortality risk.

An Evaluation of the Clinical Evidence on the Role of Inflammation and Oxidative Stress in Smoking-Mediated Cardiovascular Disease

The number of fatalities due to cardiovascular disease (CVD) continues to be far ahead of loss of human life caused by any other type of disease worldwide. According to the WHO, the annual global tobacco death toll is already 8.4 million and will reach 10 million by the year 2025. However, in contrast to other modifiable primary risk factors for CVD such as obesity, primary prevention strategies for smokers unable to quit are not available to date. This Review, by adopting the principles of evidence-based medicine, summarizes the most recent clinical studies on CVD in smokers, and concludes by suggesting a novel primary prevention strategy for CVD in smokers unable to quit. Evidence gathered from mechanistic studies involving basic research as well as large population-based approaches point to oxidative stress as the major insult imposed by cigarette smoke (CS), and a state of systemic inflammation, as signified by increased hs (high sensitivity) CRP levels in smokers, as the decisive pro-atherogenic response of the body to the initial insult. Since we identified oxidative stress induced by heavy metals as a significant pro-atherogenic activity of CS, strategies aimed at detoxifying heavy metals and combating inflammation appear as plausible approaches to counteract the accelerated onset of CVD in smokers. For this purpose, we discuss metal chelating agents and statins as promising novel primary prevention strategies in smokers unable to quit.

F2-isoprostanes are not just markers of oxidative stress

F(2)-isoprostanes are not just markers of oxidative stress. The discovery of F(2)-isoprostanes (F(2)-IsoPs) as specific and reliable markers of oxidative stress in vivo is briefly summarized here. F(2)-IsoPs are also agonists of important biological effects, such as the vasoconstriction of renal glomerular arterioles, the retinal vessel, and the brain microcirculature. In addition to the F(2)-IsoPs, E(2)- and D(2)-IsoPs can be formed by rearrangement of H(2)-IsoP endoperoxides and can give rise to cyclopentenone IsoPs, which are very reactive alpha,beta-unsaturated aldehydes. The same type of reactivity is also shown by acyclic gamma-ketoaldehydes formed as products of the IsoP pathway. Because previous studies suggested a relation between oxidative stress and collagen hyperproduction, it was investigated whether collagen synthesis is induced by F(2)-IsoPs, the most proximal products of lipid peroxidation. In contrast to aldehydes, F(2)-IsoPs act through receptors able to elicit definite signal transduction pathways. In a rat model of carbon tetrachloride-induced hepatic fibrosis, plasma F(2)-IsoPs were markedly elevated for the entire experimental period; hepatic collagen content was also increased. When hepatic stellate cells from normal liver were cultured up to activation (expression of smooth muscle alpha-actin) and then treated with F(2)-IsoPs in the concentration range found in the in vivo studies (10(-9) to 10(-8) M), a striking increase in DNA synthesis, cell proliferation, and collagen synthesis was observed. Total collagen content was similarly increased. All these stimulatory effects were reversed by the specific antagonist of the thromboxane A(2) receptor, SQ 29 548, whereas the receptor agonist, I-BOP, also had a stimulatory effect. Therefore F(2)-IsoPs generated by lipid peroxidation in hepatocytes may mediate hepatic stellate cell proliferation and collagen hyperproduction seen in hepatic fibrosis.

No effect of cigarette smoking dose on oxidized plasma proteins

Cigarette smoking is a major source of oxidative stress. Protein carbonyls have been used as a biomarker of oxidative stress because of the relative stability of carbonylated proteins and the high protein concentration in blood. Increased levels of carbonyl groups have been found in serum proteins of smokers compared to nonsmokers. However, neither the dose effect of current cigarette smoke nor other predictors of oxidative stress have been studied. Hence, we used an Enzyme-Linked Immunosorbent Assay (ELISA) to evaluate plasma protein carbonyls in smokers recruited in the Early Lung Cancer Action Project (ELCAP) program. The lung cancer screening program enrolled current and former smokers age 60 years and over without a prior cancer diagnosis. A total of 542 participants (282 men and 260 women) completed a baseline questionnaire and provided blood samples for the biomarker study. Protein oxidation was measured by derivatization of the carbonyl groups with 2,4-dinitrophenylhydrazine (DNPH) and ELISA quantitation of the DNPH group. Current smoking status was confirmed with urinary cotinine. The mean (+/-S.D.) protein carbonyl level was 17.9+/-2.9 nmol carbonyl/ml plasma. Protein carbonyls did not differ significantly by gender. Carbonyl levels were higher among current than former smokers, but these differences did not attain statistical significance, nor did differences by urine cotinine levels, pack-years, pack/day among current smokers, and smoking duration. In a multiple regression analysis, higher protein carbonyl levels were independently associated with increasing age (0.59 nmol/ml increase per 10 years, 95% CI 0.14, 1.05, p=0.01), African-American vs. white race/ethnicity, (1.30 nmol/ml, 95% CI 0.4, 2.19, p=0.008), and lower educational attainment (0.75 nmol/ml, 95% CI 0.12, 1.38, p=0.02). Although we found no significant difference between current vs. past cigarette smoking and protein carbonyls in this older group of smokers, associations were found for age, ethnicity, and educational attainment. Our results indicate that the measurement of plasma carbonyls by this ELISA technique is still an easy and suitable method for studies of diseases related to oxidative stress.

Smoking and low serum testosterone associates with high concentration of oxidized LDL

BACKGROUND

The interplay between smoking, oxidized low-density lipoprotein cholesterol (ox-LDL) and gonadal hormones has been scarcely investigated.

AIM

To investigate associations in ox-LDL and gonadal hormones in smokers and non-smokers

METHODS

Participants (n=164) were obtained from a population cohort of Finnish men aged 40-70 years. The subjects answered a detailed questionnaire on their health behaviour, medication, diseases, and different symptoms, and the hormonal and lipid profiles were measured.

RESULTS

Smokers (n=33) had higher levels of ox-LDL (21%) and more free testosterone (12%) (P<0.01 for all) than non-smokers (n=131). The difference between smokers and non-smokers in ox-LDL persisted after controlling for possible confounding factors. When the smokers were divided into two subgroups (n=16 and n=17) according to total testosterone (< or =15 and >15 nmol/L), the ox-LDL in the low-testosterone subgroup was significantly higher (30%) than in the high-testosterone group (P=0.006). Similarly in the corresponding non-smoking subgroups (n=72 and n=59), ox-LDL was significantly higher (11%) in the low-testosterone subgroup than in the high-testosterone subgroup (P=0.012).

CONCLUSIONS

Smoking men have significantly more ox-LDL than non-smoking men. Furthermore, if smoking is combined with a low serum testosterone, ox-LDL is even higher. This may suggest a higher risk for atherosclerosis.

Glucose fluctuations and activation of oxidative stress in patients with type 1 diabetes

AIMS/HYPOTHESIS

Glucose fluctuations may help predict diabetic complications. We evaluated the relation between glucose variability and oxidative stress in patients with type 1 diabetes.

METHODS

Continuous glucose monitors were inserted subcutaneously in 25 patients. During the measurement, patients collected two 24 h urine samples, while 24 healthy controls collected one 24 h urine sample for determination of 15(S)-8-iso-prostaglandin F2alpha(PGF2alpha) using HPLC tandem mass spectrometry. Mean of the daily differences (MODD), mean amplitude of glycaemic excursions (MAGE) and continuous overlapping net glycaemic action calculated with n hour time-intervals (CONGA-n) were calculated as markers for glucose variability and correlation with 15(S)-8-iso-PGF2alpha excretion was calculated.

RESULTS

Median [interquartile range (IQR)] urinary 15(S)-8-iso-PGF2alpha was higher in patients than healthy controls: 161 (140-217) pg/mg creatinine vs 118 (101-146) pg/mg creatinine (p = 0.001). Median (IQR) MODD was 3.7 (3.2-5.0) mmol/l, MAGE 7.6 (6.4-9.0) mmol/l and CONGA-1 2.3 (2.1-2.8) mmol/l. Univariate regression did not reveal an association for MODD (r2 = 0.01), MAGE (0.08) or CONGA-1 (0.07) with 15(S)-8-iso-PGF2alpha excretion, nor was an association revealed when corrected for HbA1c, age, sex and smoking. Spearman correlation coefficients (r) between 15(S)-8-iso-PGF2alpha excretion and MODD, MAGE and CONGA-1 were non-significant: -0.112, -0.381 and -0.177.

CONCLUSIONS/INTERPRETATION

We report that there is no relationship between glucose variability and urinary 15(S)-8-iso-PGF2alpha. We also confirm that patients with type 1 diabetes have higher levels of urinary 15(S)-8-iso-PGF2alpha than healthy controls, suggesting that in addition to glucose variability, other factors favouring oxidative stress may exist. We did not see a relation between high glucose variability and elevated levels of oxidative stress in patients with type 1 diabetes.

New techniques to detect oxidative stress markers: mass spectrometry-based methods to detect isoprostanes as the gold standard for oxidative stress in vivo

Free radical-induced lipid oxidation under oxidative stress has been implicated in a number of human diseases. Isoprostanes (IsoPs), isomers of prostaglandins, are one of the major classes of oxidation products derived from this oxidation process. Measurement of the levels of IsoPs by Mass Spectrometry-based methods has become the "gold standard" biomarker of oxidative stress in vivo. Significant advances have been made in understanding this important pathway of lipid peroxidation since the discovery of IsoP formation in vivo 18 years ago. Studies from our laboratory and others are discussed that have provided insights into the mechanism of formation. Furthermore, new independent studies have demonstrated that IsoPs are the most reliable available marker of lipid peroxidation in vivo, and recent work examining IsoP formation has provided valuable information about the pathogenesis of numerous human diseases. Thus, the complexity of the IsoP pathway has expanded, providing novel insights into mechanisms of lipid peroxidation in vivo and allowing investigators to explore the role of oxidative stress in human disease.

Dietary fat subgroups, zinc, and vegetable components are related to urine F2a-isoprostane concentration, a measure of oxidative stress, in midlife women

Smoking, diet, and physical activity may impact chronic diseases in part by promoting or attenuating oxidative stress. We evaluated associations between lifestyle factors and urine F(2a)-isoprostanes, a marker of oxidative stress in 1610 participants of the Study of Women's Health Across the Nation (SWAN). Dietary intake and physical activity were assessed at baseline and the 5th year 05 (Y05). These data were related to Y05 urinary F(2a)-isoprostane concentration with regression analyses. Median urine F(2a)-isoprostane concentration was 433 ng/L overall, 917 ng/L in smokers [inter-quartile range (IQR): 467, 1832 ng/L], and 403 ng/L in nonsmokers (IQR: 228, 709 ng/L; P < 0.0001 for difference). Higher trans fat intake was associated with higher urine F(2a)-isoprostane concentration; partial Spearman correlations (rho(x|y)) between Y05 urine F(2a)-isoprostane concentration and trans fatty acids was 0.19 (P = 0.03) in smokers and 0.13 (P < 0.0001) in nonsmokers. Increased log trans fat intake from baseline to Y05 was associated with higher concentration of log urine F(2a)-isoprostanes in nonsmokers (beta = 0.131, SE = 0.04, P = 0.0003). In nonsmokers, the partial correlation (rho(x|y)) between lutein and urine F(2a)-isoprostane concentration was -0.13 (P < 0.0001). Increased intake of log lutein from baseline to Y05 was also associated with lower log urine F(2a)-isoprostane concentration (beta = -0.096, SE = 0.03, P = 0.0005) in nonsmokers. Increased zinc intake from baseline to Y05 was associated with lower log urine F(2a)-isoprostane concentration in smokers and nonsmokers (beta = -0.346, SE = 0.14, P = 0.01), and -0.117, 0.04 (P = 0.001), respectively]. In conclusion, diet (fat subtypes, zinc, and vegetable components) and smoking were associated with urine F(2a)-isoprostanes, a marker of oxidative stress.

Atherosclerosis and oxidant stress: the end of the road for antioxidant vitamin treatment?

Extensive experimental data have revealed a central role for oxidative stress in atherogenesis and suggested a potential role for 'antioxidant' treatment in cardiovascular disease (CVD) [1-11]. Experimental data, however, have not translated into clinical benefit: most antioxidant vitamin trials have failed to reduce cardiovascular morbidity and mortality [12]. Moreover, recent clinical trials have suggested that mono-therapy with certain antioxidant vitamins like vitamin E may, in fact, be detrimental [13]. As a result of the disappointing outcome of 'antioxidant' vitamin trials, some authors have questioned both the utility of 'antioxidant' treatment in CVD and the supposedly central role of oxidative stress in atherogenesis [14-19]. Other investigators, however, sustain that the beneficial effects of lipid lowering and anti-hypertensive treatment are at least, in part, due to their 'antioxidant' properties, in addition to their specific pharmacological properties [20, 21]. Oxidant stress plays a pivotal role in atherogenesis, however, the clinical promise of antioxidant vitamins has failed to translate into clinical benefit. Increasing evidence suggests that more rigorous clinical trial designs are necessary to effectively divulge antioxidant utility and that a multifaceted antioxidant approach to atherosclerosis may yield the most clinical reward. This article reviews currently available evidence on the role of oxidant stress in atherosclerosis, analyzes the results of large anti-oxidant trials, and suggests ways to investigate the true role of antioxidant treatment in the clinical setting.