Modulation of oxidant stress in vivo in chronic cigarette smokers

Classifying oxidative stress by F2-isoprostane levels across human diseases: A meta-analysis

The notion that oxidative stress plays a role in virtually every human disease and environmental exposure has become ingrained in everyday knowledge. However, mounting evidence regarding the lack of specificity of biomarkers traditionally used as indicators of oxidative stress in human disease and exposures now necessitates re-evaluation. To prioritize these re-evaluations, published literature was comprehensively analyzed in a meta-analysis to quantitatively classify the levels of systemic oxidative damage across human disease and in response to environmental exposures.

In this meta-analysis, the F₂-isoprostane, 8-iso-PGF_2α, was specifically chosen as the representative marker of oxidative damage. To combine published values across measurement methods and specimens, the standardized mean differences (Hedges’ g) in 8-iso-PGF_2α levels between affected and control populations were calculated.

The meta-analysis resulted in a classification of oxidative damage levels as measured by 8-iso-PGF_2α across 50 human health outcomes and exposures from 242 distinct publications. Relatively small increases in 8-iso-PGF_2α levels (g<0.8) were found in the following conditions: hypertension (g=0.4), metabolic syndrome (g=0.5), asthma (g=0.4), and tobacco smoking (g=0.7). In contrast, large increases in 8-iso-PGF_2α levels were observed in pathologies of the kidney, e.g., chronic renal insufficiency (g=1.9), obstructive sleep apnoea (g=1.1), and pre-eclampsia (g=1.1), as well as respiratory tract disorders, e.g., cystic fibrosis (g=2.3).

In conclusion, we have established a quantitative classification for the level of 8-iso-PGF_2α generation in different human pathologies and exposures based on a comprehensive meta-analysis of published data. This analysis provides knowledge on the true involvement of oxidative damage across human health outcomes as well as utilizes past research to prioritize those conditions requiring further scrutiny on the mechanisms of biomarker generation.

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Oxidative damage is highly variable in human conditions as measured by F₂-isoprostanes.

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Respiratory tract and urogenital diseases have the highest F₂-isoprostanes.

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Cancer and cardiovascular diseases have surprisingly low F₂-isoprostanes.

Longitudinal Impact of Smoking and Smoking Cessation on Inflammatory Markers of Cardiovascular Disease Risk

OBJECTIVE

To evaluate longitudinal changes in 6 inflammatory markers that predict cardiovascular disease events among smokers making a quit attempt and to characterize their cross-sectional associations between smoking and smoking heaviness.

APPROACH AND RESULTS

In a longitudinal cohort study of contemporary smokers (n=1652), we evaluated (1) independent associations of smoking heaviness markers (exhaled carbon monoxide, cigarettes/d, pack-years) with inflammatory markers (C-reactive protein, D-dimer, fibrinogen, urinary F₂ isoprostane:creatinine [F₂:Cr] ratio, white blood cell [WBC] count, myeloperoxidase) and (2) the effects of smoking cessation and continued smoking on these inflammatory markers after 1 year, among the 888 smokers who made an aided quit attempt as part of a randomized comparative effectiveness trial or standard care. There were strong, independent associations between smoking heaviness markers and the F₂:Cr ratio, WBC, and myeloperoxidase (all P_adj<0.001), but not high-sensitivity C-reactive protein, D-dimer, or fibrinogen. Participants were mean (SD) 49.6 years old (11.6), 54% women, 34% non-white, and smoked 16.8 cigarettes/d (8.5) for 27.3 pack-years (18.6). After 1 year, the 344 successful abstainers gained more weight (4.0 [6.0] versus 0.4 [5.7] pounds; P<0.001) and had larger increases in insulin resistance scores (P=0.02) than continuing smokers. Despite these increases, abstainers had significant decreases in F₂:Cr ratio (P<0.001) and WBC counts (P<0.001). Changes in other markers were not related to quitting.

CONCLUSIONS

Smoking heaviness is associated with increased F₂:Cr ratio, myeloperoxidase, and WBC counts. Cessation improves the F₂:Cr ratio and WBC counts independent of weight change, suggesting reduced inflammation related to less oxidant stress.

A Japanese cross-sectional multicentre study of biomarkers associated with cardiovascular disease in smokers and non-smokers

We performed a cross-sectional, multicentre study in Japan to detect the differences in biomarkers of exposure and cardiovascular biomarkers between smokers and non-smokers. Several clinically relevant cardiovascular biomarkers differed significantly between smokers and non-smokers, including lipid metabolism (high-density lipoprotein cholesterol concentrations – lower in smokers), inflammation (fibrinogen and white blood cell count – both higher in smokers), oxidative stress (8-epi-prostaglandin F_2α – higher in smokers) and platelet activation (11-dehydro-thromboxane B₂ – higher in smokers) (p ≤ 0.0001). These results provide further evidence showing that cardiovascular biomarkers can discriminate smokers from non-smokers, and could be used to evaluate the risks associated with tobacco products.

A Randomized Clinical Trial Evaluating the Efficacy of an Anthocyanin-Maqui Berry Extract (Delphinol®) on Oxidative Stress Biomarkers

OBJECTIVE

Berries are a rich source of anthocyanins, and clinical data suggest that a polyphenol-rich diet may exert health-promoting effects by reducing oxidative stress. The aim of this study was to elucidate the effects of dietary supplementation with Delphinol (trademark owned by MNL Chile) standardized maqui berry (Aristotelia chilensis) extract on products of lipid peroxidation in healthy, overweight, and smoker subjects.

METHODS

In a double-blind, placebo-controlled design, 42 participants (age 45-65 years) consumed in random order either a standardized extract of maqui berry (162 mg anthocyanins) or a matched placebo, given 3 times daily for 4 weeks. The samples were collected at baseline, after the end of the supplementation, and 40 days after the end of the study. Primary outcome was the measure of oxidized low-density lipoprotein (Ox-LDL) and F2-isoprostanes in plasma and urine, respectively. Secondary outcomes included anthropometric measures, blood pressure, and lipid profile.

RESULTS

Delphinol supplementation was associated with reduced levels of Ox-LDL in the anthocyanin group compared to baseline (p < 0.05). There was also a decrease in urinary F2-isoprostanes (8-iso-prostaglandin F2α) at 4 weeks versus baseline in the Delphinol-supplemented group (p < 0.05). However, no differences in primary outcomes were evident at 40 days of follow-up. In the fourth week of the intervention, no significant differences were noted for anthropometric characteristics, ambulatory blood pressure, and lipid profile.

CONCLUSIONS

Our observations suggest that dietary interventions with maqui berry extract may improve oxidative status (Ox-LDL and F2-isoprostanes) in healthy adults, overweight adults, and adult smokers.

Effect of long-term vitamin E and selenium supplementation on urine F2-isoprostanes, a biomarker of oxidative stress

BACKGROUND

Cigarette smoking generates reactive oxidant species and contributes to systemic oxidative stress, which plays a role in the pathophysiology of chronic diseases. Nutrients with antioxidant properties, including vitamin E and selenium, are proposed to reduce systemic oxidative burden and thus to mitigate the negative health effects of reactive oxidant species.

OBJECTIVE

Our objective was to determine whether long-term supplementation with vitamin E and/or selenium reduces oxidative stress in smokers, as measured by urine 8-iso-prostaglandin F2-alpha (8-iso-PGF2α).

DESIGN

We measured urine 8-iso-PGF2α with competitive enzyme linked immunoassay (ELISA) in 312 male current smokers after 36 months of intervention in a randomized placebo-controlled trial of vitamin E (400IU/d all rac-α-tocopheryl acetate) and/or selenium (200µg/d L-selenomethionine). We used linear regression to estimate the effect of intervention on urine 8-iso-PGF2α, with adjustments for age and race.

RESULTS

Compared to placebo, vitamin E alone lowered urine 8-iso-PGF2α by 21% (p=0.02); there was no effect of combined vitamin E and selenium (intervention arm lower by 9%; p=0.37) or selenium alone (intervention arm higher by 8%; p=0.52).

CONCLUSIONS

Long-term vitamin E supplementation decreases urine 8-iso-PGF2α among male cigarette smokers, but we observed little to no evidence for an effect of selenium supplementation, alone or combined with vitamin E.

The relationship between plasma lipid peroxidation products and primary graft dysfunction after lung transplantation is modified by donor smoking and reperfusion hyperoxia

BACKGROUND

Donor smoking history and higher fraction of inspired oxygen (FIO2) at reperfusion are associated with primary graft dysfunction (PGD) after lung transplantation. We hypothesized that oxidative injury biomarkers would be elevated in PGD, with higher levels associated with donor exposure to cigarette smoke and recipient hyperoxia at reperfusion.

METHODS

We performed a nested case-control study of 72 lung transplant recipients from the Lung Transplant Outcomes Group cohort. Using mass spectroscopy, F2-isoprostanes and isofurans were measured in plasma collected after transplantation. Cases were defined in 2 ways: grade 3 PGD present at day 2 or day 3 after reperfusion (severe PGD) or any grade 3 PGD (any PGD).

RESULTS

There were 31 severe PGD cases with 41 controls and 35 any PGD cases with 37 controls. Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (28.6 pg/ml vs 19.8 pg/ml, p = 0.03). Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (29.6 pg/ml vs 19.0 pg/ml, p = 0.03) among patients reperfused with FIO2 >40%. Among recipients of lungs from donors with smoke exposure, plasma F2-isoprostane (38.2 pg/ml vs 22.5 pg/ml, p = 0.046) and isofuran (66.9 pg/ml vs 34.6 pg/ml, p = 0.046) levels were higher in severe PGD compared with control subjects.

CONCLUSIONS

Plasma levels of lipid peroxidation products are higher in patients with severe PGD, in recipients of lungs from donors with smoke exposure, and in recipients exposed to higher Fio2 at reperfusion. Oxidative injury is an important mechanism of PGD and may be magnified by donor exposure to cigarette smoke and hyperoxia at reperfusion.

A cross-sectional study of biomarkers of exposure and effect in smokers and moist snuff consumers

Cigarette smoking is a major risk factor for several chronic diseases. Epidemiological data indicate the use of smokeless tobacco (ST) is associated with significantly lower risk for smoking-related diseases compared to cigarettes. Several biomarkers of exposure (BioExp) and effect (BioEff) associated with smoking and use of moist snuff (ST) were evaluated.

A single site, cross-sectional clinical study enrolled three groups of generally healthy male smokers (SMK), moist snuff consumers (MSC), and non-tobacco consumers (NTC), and several BioExp and BioEff were evaluated.

Blood and urinary BioExp, including total nicotine equivalents and tobacco-specific nitrosamines, were higher in MSC compared to SMK. Biomarkers of combustion-related toxicants and cadmium were elevated in SMK. Elevated levels of some BioEff associated with oxidative stress (urinary isoprostanes and leukotriene E4), inflammation (white blood cell count), platelet activation (thromboxane metabolites), and lipid metabolism (apolipoprotein B100 and oxidized low-density lipoprotein) were observed in SMK relative to NTC and MSC (all p<0.05). The non-smoking groups (MSC and NTC) showed similar levels of combustion-related BioExp and BioEff.

Higher levels of exposure to nicotine and some N′-nitrosamines may be observed in MSC, and SMK are exposed to higher levels of combustion-related toxicants. Changes in BioEff consistent with some aspects of inflammation, oxidative stress, and altered lipid metabolism were detected in SMK compared to the non-smoking groups. The biomarker data further improve our understanding of pathophysiological changes and the risk continuum associated with various tobacco products, and could be useful components of future assessments of tobacco products.

Vascular endothelial dysfunction and pharmacological treatment

The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease.

Decreased argyrophilic nucleolar organiser region (AgNOR) expression in Purkinje cells: first signal of neuronal damage in sudden fetal and infant death

Aims

The nucleolus is an important cellular component involved in the biogenesis of the ribosome. This study was performed in order to validate the introduction of the argyrophilic nucleolar organiser region (AgNOR) stain technique, specific for the nucleoli detection, in neuropathological studies on sudden fetal and infant death.

Methods

In a wide set of fetuses and infants, aged from 27 gestational weeks to eight postnatal months and dead from both known and unknown causes, an in-depth neuropathological study usually applied at the Lino Rossi Research Center of the Milan University was implemented by the AgNOR method.

Results

Peculiar abnormalities of the nucleoli, as partial or total disruption above all in Purkinje cells (PCs), were exclusively found in victims of sudden fetal and infant death, and not in controls. The observed nucleolar alterations were frequently related to nicotine absorption in pregnancy.

Conclusions

We conclude that these findings represent early hallmarks of PC degeneration, contributing to the pathophysiology of sudden perinatal death.

High 15-F2t-Isoprostane Levels in Patients with a Previous History of Nonmelanoma Skin Cancer: The Effects of Supplementary Antioxidant Therapy

BACKGROUND

Phase I of this study was aimed at comparing the profiles of oxidative stress biomarkers in patients with history of nonmelanoma skin cancer (NMSC), previously treated with surgery, to the healthy subjects. Phase II aimed to evaluate the effects of supplementary antioxidant therapy on the levels of biomarkers in the case group.

MATERIALS AND METHODS

In Phase I, oxidative stress biomarkers were measured in blood samples obtained from 24 healthy subjects and 60 patients with history of NMSC previously treated with surgery. In Phase II, the 60 patients with history of NMSC were randomized into two subgroups, one receiving placebo (n = 34) and the other (n = 26) receiving vitamin C, vitamin E, and zinc supplementation for 8 weeks, followed by reevaluation of biomarkers.

RESULTS

In Phase I, patients with history of NMSC showed increased plasma concentrations of all biomarkers, but only 15-F2t-isoprostane was significantly higher than in the healthy subjects. Risk of NMSC increased by 4% for each additional 1 pg/mL increase in 15-F2t-isoprostane. In Phase II, supplementation did not significantly reduce levels of oxidative stress biomarkers.

CONCLUSION

Patients with history of NMSC had significantly high 15-F2t-isoprostane plasma levels; supplementation did not result in significant reduction of oxidative stress biomarkers. This trial was registered with ClinicalTrials.gov (ID NCT02248584).

Study of cardiovascular disease biomarkers among tobacco consumers, part 2: biomarkers of biological effect

An age-stratified, cross-sectional study was conducted in the US among healthy adult male cigarette smokers, moist snuff consumers, and non-tobacco consumers to evaluate cardiovascular biomarkers of biological effect (BoBE). Physiological assessments included flow-mediated dilation, ankle-brachial index, carotid intima-media thickness and expired carbon monoxide. Approximately one-half of the measured serum BoBE showed statistically significant differences; IL-12(p70), sICAM-1 and IL-8 were the BoBE that best differentiated among the three groups. A significant difference in ABI was observed between the cigarette smokers and non-tobacco consumer groups. Significant group and age effect differences in select biomarkers were identified.

The effect of cardioprotective diet rich with natural antioxidants on chronic inflammation and oxidized LDL during cardiac rehabilitation in patients after acute myocardial infarction

BACKGROUND

Chronic inflammation, the fundamental pathogenetic process of atherosclerosis, can be modified by pharmacological and non-pharmacological measures as a part of secondary prevention after acute myocardial infarction (AMI). The aim of our study was to determine the effect of diet, rich with natural antioxidants, added to physical activity (as a part of cardiac rehabilitation (CR) program) on inflammatory markers and ox-LDL, a marker of oxidative stress, closely involved in the process of chronic inflammation.

METHODS

41 male patients after AMI undergoing CR were divided into a diet group (supervised cardioprotective diet throughout the CR), and control group (CR without diet). We measured hsCRP, leucocytes, neutrophils, IL-6, oxLDL, exercise capacity and classic risk factors before and after CR program.

RESULTS

Patients from the diet group presented with a significant decline in classic risk factors (BMI, waist circumference, waist to hip ratio, systolic blood pressure, heart rate, blood glucose, total cholesterol, LDL, TAG) and inflammatory markers (hsCRP, leucocytes, neutrophils) compared to control group. Furthermore, when studying nonsmokers, we observed significant decline of oxLDL in the diet group.

CONCLUSIONS

The addition of cardioprotective diet, rich with natural antioxidants, to physical activity as a part of a CR program, positively modifies not just classic risk factors and exercise capacity, but also diminishes chronic inflammation markers. These effects, and oxLDL decline were most prominent in nonsmoking patients.

Effect of common single nucleotide polymorphisms in COX-1 gene on related metabolic activity in diabetic patients treated with acetylsalicylic acid

INTRODUCTION

The objective of this study was to investigate the effect of common single nucleotide genomic polymorphisms in the cyclooxygenase-1 (COX-1) gene on the thromboxane A2 (TxA2) metabolite concentrations in serum and urine, as well as on prostaglandin F2α (PGF2α) urinary excretion in the diabetic population on acetylsalicylic acid (ASA) therapy.

MATERIAL AND METHODS

The study cohort consisted of 284 Caucasians with diabetes type 2 who had been taking ASA tablets at the dose of 75 mg/day for at least 3 months. Genotyping for the 4 selected SNPs within the COX-1 gene (two nonsynonymous-coding variants, rs3842787 [C50T, P17L] and rs5789 [C174A, L237M]; and two other synonymous SNPs, rs3842788 [G128A, Q41Q] and rs5788 [C644A]) was performed using the Sequenom iPLEX platform.

RESULTS

No statistically significant results were observed for the investigated SNPs and measured metabolites in the investigated cohort of patients. Statistically significant differences in S-TxB2 could however be observed for rs5788 in the subgroup of patients with very high S-TxB2 concentrations. In particular, more patients who were carriers of the minor allele for this polymorphism were observed in the group with S-TxB2 levels > 95(th) percentile, when compared with similar carriers in the group with S-TxB2 < 95(th) percentile (20% vs. 1.1%, respectively, p < 0.001, Mann-Whitney test).

CONCLUSIONS

The results of our study suggest that the four investigated common SNPs in the COX1 gene are not associated with obviously altered TxA2 metabolism and PGF2α synthesis in the investigated diabetic cohort treated with ASA.

Association between aspirin use and the prevalence of nonalcoholic fatty liver disease: a cross-sectional study from the Third National Health and Nutrition Examination Survey

BACKGROUND

Many basic mechanistic studies found that aspirin inhibited multiple pathways involved in non-alcoholic fatty liver disease (NAFLD) development.

AIM

To investigate an association between aspirin use and NAFLD prevalence in the general US population.

METHODS

We conducted a cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III). We included 11 416 adults aged 20-74 years who underwent ultrasonography; of those, 2889 were identified as having NAFLD and 8527 as controls. Aspirin use during the month prior to interview was categorised as never use (0 times), occasional use (1-14 times) and regular use (≥15 times).

RESULTS

In the multivariate unconditional logistic regression analysis, regular relative to no aspirin use was inversely associated with prevalent NAFLD [odds ratio (OR) = 0.62, 95% confidence interval (CI) 0.51-0.74; P for trend = 0.04], a finding that was primarily limited to men (OR = 0.32, 95% CI 0.23-0.45; P for interaction < 0.01) and those who were older (>60 years) (OR = 0.21, 95% CI 0.14-0.30; P for interaction < 0.01).

CONCLUSION

These findings, from the first human study to investigate an association of aspirin use with NAFLD, suggest that regular aspirin use (≥ 15 times per month) may be associated with a lower prevalence of NAFLD, primarily among men and older patients.

Smoking and increased Alzheimer's disease risk: a review of potential mechanisms

BACKGROUND

Cigarette smoking has been linked with both increased and decreased risk for Alzheimer's disease (AD). This is relevant for the US military because the prevalence of smoking in the military is approximately 11% higher than in civilians.

METHODS

A systematic review of published studies on the association between smoking and increased risk for AD and preclinical and human literature on the relationships between smoking, nicotine exposure, and AD-related neuropathology was conducted. Original data from comparisons of smoking and never-smoking cognitively normal elders on in vivo amyloid imaging are also presented.

RESULTS

Overall, literature indicates that former/active smoking is related to a significantly increased risk for AD. Cigarette smoke/smoking is associated with AD neuropathology in preclinical models and humans. Smoking-related cerebral oxidative stress is a potential mechanism promoting AD pathology and increased risk for AD.

CONCLUSIONS

A reduction in the incidence of smoking will likely reduce the future prevalence of AD.

Aspirin in type 2 diabetes, a randomised controlled study: effect of different doses on inflammation, oxidative stress, insulin resistance and endothelial function

OBJECTIVES

The effect of aspirin upon platelet function is well documented although experimental studies suggest that aspirin may also affect oxidative stress, vascular inflammation, endothelial dysfunction and dysglycaemia. The optimal dose of aspirin for cardiovascular protection in type 2 diabetes is still debated. We examined the effects of different doses of aspirin upon these novel markers of cardiovascular risk and any association between aspirin-mediated changes in these markers.

METHODOLOGY

Subjects with type 2 diabetes attended for baseline evaluation including BMI, glycaemic and lipid markers, endothelial function (photoplethysmography), insulin resistance (HOMA), inflammation (sVCAM-1 and Hs-CRP) and markers of oxidative stress [total anti-oxidant status (TAOS and FRAP), whole blood total glutathione (GSH) assays]. Subjects then received in random, sequential, blinded fashion aspirin 75 mg day(-1) , aspirin 300 mg day(-1) , aspirin 3.6 g day(-1) or placebo for 2 weeks with a 2-week washout. The above investigations were repeated after each intervention. Aspirin-related changes compared with placebo were analysed using repeated measures ANOVA.

RESULTS

Subjects = 17 (M - 12; F - 5), mean age - 57.4 ± 9.1 years (mean ± 1 SD), HbA1c - 63 ± 13 mmol mol(-1) (7.9 ± 1.2%), total cholesterol 4.57 ± 1.01 mmol l(-1) . At baseline TAOS value was 59.3 ± 9.7 μM AEAC (Ascorbate Equivalent Anti-oxidant Concentration), glutathione 302.2 ± 183.3 mmol l(-1) and FRAP 0.86 ± 0.23 mM FeII. None of the aspirin doses had a significant impact upon BMI, blood pressure, lipid parameters, insulin sensitivity (HOMA), FRAP, TAOS, GSH, endothelial function, glycaemic control (fructosamine) or inflammation (sVCAM-1 and HsCRP).

CONCLUSIONS

Aspirin exhibited no significant dose-dependent effect on markers of vascular inflammation, oxidative stress, insulin resistance and endothelial function (photoplethysmography) when used in type 2 diabetes over a 2-week period. (

CLINICAL TRIALS REGISTRATION

NCT00898950, EUDRACT:2004-001418-14).

[Antiplatelet therapy: resistance to traditional antiaggregation drugs and role of new antiplatelet agents]

Platelet aggregation plays a key role in the development of major cardiovascular events (MACE) related to atherothrombosis. Since the appearance of coronary stenting, the importance of measuring and modulating platelet activity has considerably increased in the scientific literature during the last decade. Double antiplatelet therapy with aspirin and clopidogrel administrated to stent carriers has widely demonstrated its efficacy in the prevention of MACE compared with aspirin alone. These benefits are also present when a conservatory approach is chosen for acute coronary syndrome management. However, there are an important number of patients who develop MACE despite optimal dual antiplatelet therapy, most likely related to an incomplete platelet activity inhibition. Many studies suggest an important inter-individual variability in the response to the drugs, maybe related, at least in part, to the use of different assessment techniques of platelet aggregation. Other authors suggest an incomplete platelet inhibition as a possible explanation for the presence of MACE in patients under optimal antiplatelet therapy. Resistance to usual drugs has become a clinically relevant issue that requires an individual approach where new antiplatelet agents, such as prasugrel or ticagrelor, could play an important role as stated in current consensus documents.

The smoking-associated oxidant hypothiocyanous acid induces endothelial nitric oxide synthase dysfunction

The smoking-associated oxidant hypothiocyanous acid converts active dimeric endothelial cell nitric oxide synthase into its monomer form, decreases enzyme activity and releases Zn2+. This is ascribed to targeting of the critical Zn2+–thiol cluster by this thiol-specific oxidant.

Evaluation of serum arginase I as an oxidative stress biomarker in a healthy Japanese population using a newly established ELISA

OBJECTIVE

We reported previously that serum arginase I increased in asthmatic patients and was associated with oxidative stress in a small healthy population. However, the exact association of arginase I with oxidative stress is not known. The present study aimed to analyze the association of arginase I with oxidative stress in a larger healthy population by a newly established ELISA.

DESIGN AND METHODS

The new ELISA for the measurement of human arginase I was established by generating recombinant arginase I protein in human arginase I gene-transfected Escherichia coli via an ARG1 cDNA fragment-inserted vector and -specific antibody in rabbits. Serum arginase I was evaluated in a cross-sectional study on a healthy population (n=721) by comparing a commercial ELISA kit with the new ELISA.

RESULTS

The mean levels of serum arginase I were 20.3 ± 0.7 ng/mL and 4.7 ± 0.2 ng/mL using the commercial ELISA kit and the new ELISA, respectively. Arginase I was correlated with WBC, RBC, hs-CRP, 8-OHdG, HDL-c, ALT, and BMI. Logistic regression analysis showed independent positive associations of arginase I with WBC, RBC, and urinary 8-OHdG and inverse independent associations with serum insulin and age. The association of arginase I with hs-CRP was not independent.

CONCLUSION

The independent associations of arginase I with urinary 8-OHdG and serum insulin may reflect its involvement in oxidative stress and diabetes mellitus.

Lung cancer biomarkers for the assessment of modified risk tobacco products: an oxidative stress perspective

Manufacturers have developed prototype cigarettes yielding reduced levels of some tobacco smoke toxicants, when tested using laboratory machine smoking under standardised conditions. For the scientific assessment of modified risk tobacco products, tests that offer objective, reproducible data, which can be obtained in a much shorter time than the requirements of conventional epidemiology are needed. In this review, we consider whether biomarkers of biological effect related to oxidative stress can be used in this role. Based on published data, urinary 8-oxo-7,8-dihydro-2-deoxyguanosine, thymidine glycol, F2-isoprostanes, serum dehydroascorbic acid to ascorbic acid ratio and carotenoid concentrations show promise, while 4-hydroxynonenal requires further qualification.

Aspirin treatment failure: is this a real phenomenon? A review of the aetiology and how to treat it

Multiple clinical trials have shown that aspirin can reduce all cardiovascular events in primary and secondary prevention and yet there is a large population in whom aspirin fails. This review brings together the evidence and controversies surrounding the definition of ‘aspirin treatment failure’, its clinical significance and the possible approaches to managing such patients. Several different assays have been developed to measure the biochemical action of aspirin. At present there is no ‘gold standard’ and there is massive disparity between methods. Studies thus far have shown inconsistent results and to date the treatment of aspirin therapy failure is left to the discretion of the leading physician.

F2-isoprostanes as markers of oxidant stress: an overview

The isoprostanes are a unique series of prostaglandin-like compounds formed in vivo via a non-enzymatic mechanism involving the free radical-initiated peroxidation of arachidonic acid. This unit summarizes selected aspects regarding current knowledge of these compounds and their value as markers of oxidative injury. Novel aspects related to the biochemistry of isoprostane formation are discussed and methods by which these compounds can be analyzed and quantified are summarized. A considerable portion of this unit examines the utility of F(2)-isoprostanes as markers of oxidant injury in vitro and in vivo. Numerous studies carried out over the past decade have shown that these compounds are extremely accurate measures of lipid peroxidation in animals and humans and have illuminated the role of oxidant injury in a number of human diseases.

Markers of oxidant stress that are clinically relevant in aging and age-related disease

Despite the long held hypothesis that oxidant stress results in accumulated oxidative damage to cellular macromolecules and subsequently to aging and age-related chronic disease, it has been difficult to consistently define and specifically identify markers of oxidant stress that are consistently and directly linked to age and disease status. Inflammation because it is also linked to oxidant stress, aging, and chronic disease also plays an important role in understanding the clinical implications of oxidant stress and relevant markers. Much attention has focused on identifying specific markers of oxidative stress and inflammation that could be measured in easily accessible tissues and fluids (lymphocytes, plasma, serum). The purpose of this review is to discuss markers of oxidant stress used in the field as biomarkers of aging and age-related diseases, highlighting differences observed by race when data is available. We highlight DNA, RNA, protein, and lipid oxidation as measures of oxidative stress, as well as other well-characterized markers of oxidative damage and inflammation and discuss their strengths and limitations. We present the current state of the literature reporting use of these markers in studies of human cohorts in relation to age and age-related disease and also with a special emphasis on differences observed by race when relevant.

Vitamins e and C alleviate the germ cell loss and oxidative stress in cryptorchidism when administered separately but not when combined in rats

The antioxidant effects of vitamins C and E on cryptorchidism-induced oxidative stress were investigated in male Sprague-Dawley rats. Forty rats (200-250 g) were randomly divided in a blinded fashion into five groups (n = 8). Group 1 was sham operated and treated with vehicle (corn-oil, 10 mL/kg). Groups 2, 3, 4, and 5 were rendered unilaterally cryptorchid and treated with vehicle (10 mL/kg), vitamin E solution (75 mg/kg), vitamin C solution (1.25 g/kg), and combination of vitamin E (75 mg/kg) and vitamin C (1.25 g/kg) solutions, respectively. Germ cell count, superoxide dismutase (SOD), total protein (TP), and testicular weight (TW) were lower, but malondialdhyde (MDA) was higher in the cryptorchid rats than the sham-operated rats. When administered separately, vitamins C and E increased germ cell count, SOD, TP, and TW but did not reduce MDA in the cryptorchid rats when compared to the vehicle-treated cryptorchid rats. However, there was no significant difference in these parameters between vehicle-treated and combined vitamins C- and E-treated rats. This suggests that vitamins E and C alleviate the germ cell loss and oxidative stress in cryptorchidism when administered separately but not when combined in rats.

Authors' perspective: What is the optimum intake of vitamin C in humans?

The recommended dietary allowance (RDA) of vitamin C has traditionally been based on the prevention of the vitamin C deficiency disease, scurvy. While higher intakes of vitamin C may exert additional health benefits, the limited Phase III randomized placebo-controlled trials (RCTs) of vitamin C supplementation have not found consistent benefit with respect to chronic disease prevention. To date, this has precluded upward adjustments of the current RDA. Here we argue that Phase III RCTs-designed principally to test the safety and efficacy of pharmaceutical drugs-are ill suited to assess the health benefits of essential nutrients; and the currently available scientific evidence is sufficient to determine the optimum intake of vitamin C in humans. This evidence establishes biological plausibility and mechanisms of action for vitamin C in the primary prevention of coronary heart disease, stroke, and cancer; and is buttressed by consistent data from prospective cohort studies based on blood analysis or dietary intake and well-designed Phase II RCTs. These RCTs show that vitamin C supplementation lowers hypertension, endothelial dysfunction, chronic inflammation, and Helicobacter pylori infection, which are independent risk factors of cardiovascular diseases and certain cancers. Furthermore, vitamin C acts as a biological antioxidant that can lower elevated levels of oxidative stress, which also may contribute to chronic disease prevention. Based on the combined evidence from human metabolic, pharmacokinetic, and observational studies and Phase II RCTs, we conclude that 200 mg per day is the optimum dietary intake of vitamin C for the majority of the adult population to maximize the vitamin's potential health benefits with the least risk of inadequacy or adverse health effects.

An eicosanoid-centric view of atherothrombotic risk factors

Cardiovascular disease is the foremost cause of morbidity and mortality in the Western world. Atherosclerosis followed by thrombosis (atherothrombosis) is the pathological process underlying most myocardial, cerebral, and peripheral vascular events. Atherothrombosis is a complex and heterogeneous inflammatory process that involves interactions between many cell types (including vascular smooth muscle cells, endothelial cells, macrophages, and platelets) and processes (including migration, proliferation, and activation). Despite a wealth of knowledge from many recent studies using knockout mouse and human genetic studies (GWAS and candidate approach) identifying genes and proteins directly involved in these processes, traditional cardiovascular risk factors (hyperlipidemia, hypertension, smoking, diabetes mellitus, sex, and age) remain the most useful predictor of disease. Eicosanoids (20 carbon polyunsaturated fatty acid derivatives of arachidonic acid and other essential fatty acids) are emerging as important regulators of cardiovascular disease processes. Drugs indirectly modulating these signals, including COX-1/COX-2 inhibitors, have proven to play major roles in the atherothrombotic process. However, the complexity of their roles and regulation by opposing eicosanoid signaling, have contributed to the lack of therapies directed at the eicosanoid receptors themselves. This is likely to change, as our understanding of the structure, signaling, and function of the eicosanoid receptors improves. Indeed, a major advance is emerging from the characterization of dysfunctional naturally occurring mutations of the eicosanoid receptors. In light of the proven and continuing importance of risk factors, we have elected to focus on the relationship between eicosanoids and cardiovascular risk factors.

Maternal smoking decreases antioxidative status of human breast milk

OBJECTIVE

To evaluate the influence of maternal smoking on antioxidative capacity and intensity of oxidative damage in breast milk.

STUDY DESIGN

The study group (n=30) was comprised of postpartum women who declared smoking more than five cigarettes per day during pregnancy and lactation (confirmed by the urinalysis of cotinine concentration), and their newborns. Control group included 29 non-smoking postpartum women and their newborns. Colostrum samples were collected on the 3rd day after delivery and breast milk samples between the 30th and the 32nd day after delivery. Morning maternal and neonatal urine samples were obtained on the day of the mature milk sampling. Isoprostane concentrations in colostrum/mature milk and urine were determined immunoenzymatically. Total Antioxidant Status (TAS) of colostrum/breast milk was determined by Rice-Evans and Miller method.

RESULT

Colostrum TAS in smokers was significantly lower than in non-smokers (P=0.006). In both groups, the TAS of mature milk was higher compared with colostrum, but significant differences were observed amongst smokers only (P=0.001). In smokers the isoprostane concentration of mature milk was significantly higher than the colostrum concentration (P=0.001). Significant inverse correlation between maternal urinary isoprostane concentration and the TAS of mature breast milk was observed in smokers (R=-0.525, P=0.023), but not in non-smokers (R=0.161, P=0.422).

CONCLUSION

This study revealed that maternal smoking triggers harmful effects on an infant by impairing pro-oxidant-antioxidant balance of breast milk.

High plasma thiocyanate levels modulate protein damage induced by myeloperoxidase and perturb measurement of 3-chlorotyrosine

Smokers have an elevated risk of atherosclerosis but the origin of this elevated risk is incompletely defined, though increasing evidence supports a role for the oxidant-generating enzyme myeloperoxidase (MPO). In previous studies we have demonstrated that smokers have elevated levels of thiocyanate ions (SCN(-)), relative to nonsmokers, and increased thiol oxidation, as SCN(-) is a favored substrate for MPO, and the resulting hypothiocyanous acid (HOSCN) targets thiol groups rapidly and selectively. In this study we show that increased HOSCN formation by MPO diminishes damage to nonthiol targets on both model proteins and human plasma proteins. Thus high SCN(-) levels protect against HOCl- and MPO-mediated damage to methionine, tryptophan, lysine, histidine, and tyrosine residues on proteins. Furthermore, levels of the HOCl-mediated marker compound 3-chlorotyrosine and the cross-linked product dityrosine are decreased. Plasma protein 3-chlorotyrosine levels induced by HOCl exposure in nonsmokers are elevated over the levels detected in smokers when exposed to identical oxidative insult (P<0.05), and a strong inverse correlation exists between plasma SCN(-) levels and 3-chlorotyrosine concentrations (r=0.6182; P<0.0001). These correlations were also significant for smokers (r=0.2724; P<0.05) and nonsmokers (r=0.4141; P<0.01) when analyzed as individual groups. These data indicate that plasma SCN(-) levels are a key determinant of the extent and type of protein oxidation induced by MPO on isolated and plasma proteins and that smoking status and resulting high SCN(-) levels can markedly modulate the levels of the widely used biomarker compound 3-chlorotyrosine.

Influence of cigarette smoking on synthesis of eicosanoids, isoprostanes and lipoxygenase metabolites in apical periodontitis

Arachidonic acid (AA) is metabolized to eicosanoids and isoprostanes (IPs) via different pathways. The presence of granuloma in apical periodontitis (AP) is linked with inflammation and the synthesis of metabolites of AA.

OBJECTIVE

We investigated the conversion rate of (14)C labelled arachidonic acid ((14)C-AA), the lipoxygenases (LOX) products and the endogenous synthesis of eicosanoids and IPs in extracted granuloma. Furthermore, we assessed if there are markers for bone destruction and the influence of cigarette smoking.

PATIENTS AND METHODS

In 46 patients with symptoms and corresponding radiological signs of AP, teeth were extracted including the periapical granuloma. The endogenous synthesis of eicosanoids and IPs, the conversion rate of (14)C-AA and LOX products in extracted granuloma were analyzed.

RESULTS

We found that smoking increases significantly the synthesis of IPs and LOX-metabolites in granuloma. Furthermore, smoking may have contributed to significant differences in qualitative and quantitative profile of eicosanoids, IPs and the conversion rate of (14)C-AA independent of the size of the granuloma.

CONCLUSIONS

Our data demonstrate that in smokers with granuloma due to AP products of lipid peroxidation as 8-iso-PGF(2α) and products of the LOX-pathway are increased at the expense of cyclooxygenase products. The size of granuloma did not influence the amount of synthesized eicosanoids, IPs or LOX-metabolites out of (14)C-AA whereas cigarette smoking was a significantly influencing and modifiable risk factor.

Pleiotropic benefit of monomeric and oligomeric flavanols on vascular health--a randomized controlled clinical pilot study

Background

Cardiovascular diseases are expanding to a major social-economic burden in the Western World and undermine man's deep desire for healthy ageing. Epidemiological studies suggest that flavanol-rich foods (e.g. grapes, wine, chocolate) sustain cardiovascular health. For an evidenced-based application, however, sound clinical data on their efficacy are strongly demanded.

Methods

In a double-blind, randomized, placebo-controlled intervention study we supplemented 28 male smokers with 200 mg per day of monomeric and oligomeric flavanols (MOF) from grape seeds. At baseline, after 4 and 8 weeks we measured macro- and microvascular function and a cluster of systemic biomarkers for major pathological processes occurring in the vasculature: disturbances in lipid metabolism and cellular redox balance, and activation of inflammatory cells and platelets.

Results

In the MOF group serum total cholesterol and LDL decreased significantly (P≤0.05) by 5% (n = 11) and 7% (n = 9), respectively in volunteers with elevated baseline levels. Additionally, after 8 weeks the ratio of glutathione to glutathione disulphide in erythrocytes rose from baseline by 22% (n = 15, P<0.05) in MOF supplemented subjects. We also observed that MOF supplementation exerts anti-inflammatory effects in blood towards ex vivo added bacterial endotoxin and significantly reduces expression of inflammatory genes in leukocytes. Conversely, alterations in macro- and microvascular function, platelet aggregation, plasma levels of nitric oxide surrogates, endothelin-1, C-reactive protein, fibrinogen, prostaglandin F2alpha, plasma antioxidant capacity and gene expression levels of antioxidant defense enzymes did not reach statistical significance after 8 weeks MOF supplementation. However, integrating all measured effects into a global, so-called vascular health index revealed a significant improvement of overall vascular health by MOF compared to placebo (P≤0.05).

Conclusion

Our integrative multi-biomarker approach unveiled the pleiotropic vascular health benefit of an 8 weeks supplementation with 200 mg/d MOF in humans.

Trial Registration

ClinicalTrials.gov NCT00742287

Associations between functional polymorphisms in antioxidant defense genes and urinary oxidative stress biomarkers in healthy, premenopausal women

Functional polymorphisms in endogenous antioxidant defense genes including manganese superoxide dismutase (MnSOD), catalase (CAT), and glutathione peroxidase (GPX-1) have been linked with risk of cancer at multiple sites. Although it is presumed that these germline variants impact disease risk by altering the host's ability to detoxify mutagenic reactive oxygen species, very few studies have directly examined this hypothesis. Concentrations of 8-isoprostane F2α (8-iso-PGF2α) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoxdG)-sensitive indicators of lipid peroxidation and DNA oxidation, respectively-were measured in 24-h urine samples obtained from 93 healthy, premenopausal women participating in a dietary intervention trial. In addition, DNA was extracted from blood for genotyping of MnSOD Val16Ala, CAT-262 C > T, and GPX1 Pro198Leu genotypes by Taqman assay. Although geometric mean concentrations of 8-iso-PGF2(α) and 8-oxoxdG varied across several study characteristics including race, education level, body mass index, and serum antioxidant levels, there was little evidence that these biomarkers differed across any of the examined genotypes. In summary, functional polymorphisms in endogenous antioxidant defense genes do not appear to be strongly associated with systemic oxidative stress levels in young, healthy women.

High plasma thiocyanate levels in smokers are a key determinant of thiol oxidation induced by myeloperoxidase

Smokers have an elevated risk of atherosclerosis but the origins of this elevated risk are incompletely defined, though evidence supports an accumulation of the oxidant-generating enzyme myeloperoxidase (MPO) in the inflamed artery wall. We hypothesized that smokers would have a high level of thiocyanate (SCN(-)), a preferred substrate for MPO, which in turn would predispose to thiol oxidation, an established independent risk factor for atherosclerosis. In this study it is shown that on exposure to MPO/H(2)O(2), thiols on plasma proteins from nonsmokers were increasingly oxidized with increasing added SCN(-) concentrations. Plasma from smokers contained significantly higher endogenous levels of SCN(-) than that from nonsmokers (131±31 vs 40±24 μM, P<0.0001). When plasma from smokers and nonsmokers was exposed to MPO/H(2)O(2)-stimulated oxidation, a strong positive correlation (r=0.8139, P<0.0001) between the extent of thiol oxidation and the plasma SCN(-) concentrations was observed. Computational calculations indicate a changeover from HOCl to HOSCN as the major MPO-generated oxidant in plasma, with increasing SCN(-) levels. These data indicate that plasma SCN(-) levels are a key determinant of the extent of thiol oxidation on plasma proteins induced by MPO, and implicate HOSCN as an important mediator of inflammation-induced oxidative damage to proteins in smokers.

Demographic and lifestyle factors and selenium levels in men and women in the U.S

Selenium is an antioxidant trace element linked to cardiovascular disease and cancer. Although diet is a major source, relatively little else is known about independent determinants of selenium levels in free-living humans. In this study, we aimed to investigate the independent demographic, lifestyle, and dietary determinants of selenium levels in 1,997 men and 1,905 women in two large prospective U.S. cohorts. Toenail selenium levels were quantified using neutron activation analysis. Diet, geographic residence, demographic, and environmental factors were assessed by validated self-administered questionnaires. Multivariate generalized linear models were conducted to assess the independent relations of these factors with toenail selenium levels, correcting for measurement error in the diet. In multivariable-adjusted analyses, independent predictors of higher selenium were male gender (6.3% higher levels); living in West and Northern-Midwest U.S. regions (8.9% and 7.4% higher than Southern-Midwest regions, respectively); consumption of beef and bread products (between 0.7 - 2.5% higher per daily serving); and selenium supplement use (6.9% higher than non-users); whereas cigarette smoking (5-10% lower than never smokers) , older age (0.6% lower per 5 years), and consumption of eggs, white rice, dairy products, coffee, and alcohol (between 0.1 to 2.0% lower per daily serving) were associated with lower selenium. Multiple dietary and non-dietary factors independently predicted selenium levels, suggesting that both consumption and non-dietary processes (e.g., related to oxidant status) may affect levels. Significant geographic variation in selenium levels exists in the US.

Relationship between biomarkers of cigarette smoke exposure and biomarkers of inflammation, oxidative stress, and platelet activation in adult cigarette smokers

BACKGROUND

Cigarette smoking is a risk factor for several diseases, including cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer, but the role of specific smoke constituents in these diseases has not been clearly established.

METHODS

The relationships between biomarkers of potential harm (BOPH), associated with inflammation [white blood cell (WBC), high sensitivity C-reactive protein (hs-CRP), fibrinogen, and von Willebrand factor (vWF)], oxidative stress [8-epi-prostaglandin F(2α) (8-epiPGF(2α))] and platelet activation [11-dehydro-thromboxin B(2) (11-dehTxB(2))], and machine-measured tar yields (grouped into four categories), biomarkers of exposure (BOE) to cigarette smoke: nicotine and its five metabolites (nicotine equivalents), 4-methylnitrosamino-1-(3-pyridyl)-1-butanol (total NNAL), carboxyhemoglobin, 1-hydroxypyrene, 3-hydroxypropylmercapturic acid, and monohydroxybutenyl-mercapturic acid, were investigated in 3,585 adult smokers and 1,077 nonsmokers.

RESULTS

Overall, adult smokers had higher levels of BOPHs than nonsmokers. Body mass index (BMI), smoking duration, tar category, and some of the BOEs were significant factors in the multiple regression models. Based on the F value, BMI was the highest ranking factor in the models for WBC, hs-CRP, fibrinogen, and 8-epiPGF(2α), respectively, and gender and smoking duration for 11-dehTxB(2) and vWF, respectively.

CONCLUSIONS

Although several demographic factors and some BOEs were statistically significant in the model, the R(2) values indicate that only up to 22% of the variability can be explained by these factors, reflecting the complexity and multifactorial nature of the disease mechanisms.

IMPACT

The relationships between the BOEs and BOPHs observed in this study may help with the identification of appropriate biomarkers and improve the design of clinical studies in smokers.

Biomarkers of oxidative damage in cigarette smokers: which biomarkers might reflect acute versus chronic oxidative stress?

Cigarette smoking predisposes to the development of multiple diseases involving oxidative damage. We measured a range of oxidative damage biomarkers to understand which differ between smokers and nonsmokers and if the levels of these biomarkers change further during the act of smoking itself. Despite overnight abstinence from smoking, smokers had higher levels of plasma total and esterified F(2)-isoprostanes, hydroxyeicosatetraenoic acid products (HETEs), F(4)-neuroprostanes, 7-ketocholesterol, and 24- and 27-hydroxycholesterol. Levels of urinary F(2)-isoprostanes, HETEs, and 8-hydroxy-2'-deoxyguanosine were also increased compared with age-matched nonsmokers. Several biomarkers (plasma free F(2)-isoprostanes, allantoin, and 7β-hydroxycholesterol and urinary F(2)-isoprostane metabolites) were not elevated. The smokers were then asked to smoke a cigarette; this acute smoking elevated plasma and urinary F(2)-isoprostanes, plasma allantoin, and certain cholesterol oxidation products compared to presmoking levels, but not plasma HETEs or urinary 8-hydroxy-2'-deoxyguanosine. Smokers showed differences in plasma fatty acid composition. Our findings confirm that certain oxidative damage biomarkers are elevated in smokers even after a period of abstinence from smoking, whereas these plus some others are elevated after acute smoking. Thus, different biomarkers do not measure identical aspects of oxidative stress.

Cigarette smoke inhibits brain mitochondrial adaptations of exercised mice

Physical exercise and smoking are environmental factors that generally cause opposite health-promoting adaptations. Both physical exercise and smoking converge on mitochondrial adaptations in various tissues, including the pro-oxidant nervous system. Here, we analyzed the impact of cigarette smoking on exercise-induced brain mitochondrial adaptations in the hippocampus and pre-frontal cortex of adult mice. The animals were exposed to chronic cigarette smoke followed by 8 weeks of moderate-intensity physical exercise that increased mitochondrial activity in the hippocampus and pre-frontal cortex in the non-smoker mice. However, mice previously exposed to cigarette smoke did not present these exercise-induced mitochondrial adaptations. Our results suggest that smoking can inhibit some brain health-promoting changes induced by physical exercise.

Role of carbon monoxide in impaired endothelial function mediated by acute second-hand tobacco, incense, and candle smoke exposures

The aim of this study was to determine if carbon monoxide (CO) is responsible for acute adverse cardiovascular effects of different sources of smoke: second-hand tobacco smoke (SHS), incense and candle smoke. Endothelial function was tested using flow-mediated dilation (FMD) in pigs and was shown to be sensitive to nitric oxide synthase blockade. Subsequent experiments showed that FMD was significantly impaired compared to sham-exposed pigs at 30 min after a 30-min exposure to all three sources of smoke. In contrast, SHS significantly increased systolic, diastolic and pulse pressures compared to sham-exposure, while both incense and candle smoke exposure had no effect. The FMD impairment correlated well with CO levels in the exposure chamber, but not total particulates or venous CO-hemoglobin. Therefore, this study suggests a gas phase component of smoke that accompanies CO, but not CO itself, is responsible for acute endothelial dysfunction after SHS, incense or candle smoke exposure.

Antiproliferative effect of estrogen in vascular smooth muscle cells is mediated by Kruppel-like factor-4 and manganese superoxide dismutase

The mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) and the zinc finger transcription factor Kruppel-like factor-4 (KLF4) are involved in the regulation of redox homeostasis, apoptosis and cell proliferation. We have shown that estrogen exerts antioxidative actions via induction of MnSOD in cultured rat aortic vascular smooth muscle cells (VSMC). The purpose of the present study was to investigate whether estrogen inhibits VSMC proliferation via alteration of KLF4 and MnSOD expression. In cultured rat aortic VSMC, estrogen binding to estrogen receptor-alpha led to rapid increase in KLF4 expression and reduction of cell proliferation by 50%. Protein separation revealed that KLF4 was shifted to the nucleus when VSMC were treated with estrogen. Estrogen-mediated induction of KLF4 and the antiproliferative effect involved activation of PI-3 kinase, Akt phosphorylation and induction of NO synthase activity. Experiments in freshly isolated denuded aortic segments revealed an increase in KLF4 abundance after estrogen treatment and demonstrated that eNOS is expressed in the media at low levels. Transfection experiments showed that estrogen-induced overexpression of MnSOD required KLF4 and that both KLF4 and MnSOD were indispensable for the observed antiproliferative effect of estrogen in VSMC. To confirm these data in vivo, we investigated neointima formation after carotid artery injury in wild-type (WT) and MnSOD+/- mice. Estrogen deficiency led to enhanced neointima formation and higher numbers of Ki67-positive proliferating cells in the neointima of ovariectomized WT and MnSOD+/- mice. Moreover, MnSOD+/- mice showed more extensive neointima formation and Ki67 immunostaining. Interestingly, estrogen replacement prevented neointima formation in WT mice but failed to completely inhibit neointima formation in MnSOD+/- mice. Cultured VSMC derived from MnSOD+/- mice showed enhanced proliferation as compared to WT VSMC, and estrogen treatment failed to inhibit proliferation in MnSOD+/- VSMC. In conclusion, these data demonstrate the importance of MnSOD and KLF4 for proliferation control in VSMC. Our results provide novel insights into how proliferation of VSMC is regulated by estrogen and may help to identify novel targets for the treatment of vascular diseases such as restenosis.

F2-isoprostanes as an indicator and risk factor for coronary heart disease

Coronary heart disease (CHD) is the leading single cause of death in the United States and most Western countries, killing more than 400,000 Americans per year. Although CHD often manifests suddenly as a fatal myocardial infarction, the atherosclerosis that gives rise to the infarction develops gradually and can be markedly slowed or even reversed through pharmacological and lifestyle interventions. These same atherosclerotic processes also drive related vascular diseases such as stroke and peripheral artery disease, and individuals surviving occlusive events often develop additional complications including ischemic cardiomyopathy and heart failure. Therefore, better detection of subclinical atherosclerosis, along with more effective treatments, could significantly reduce the rate of death from CHD and related vascular diseases in the United States. In recent years, oxidation of polyunsaturated fatty acids (PUFAs) in plasma lipoproteins has been postulated to be a critical step in the development of atherosclerosis. If so, then monitoring lipid peroxidation should be a useful indicator of disease risk and progression. This review focuses on the evidence that specific PUFA peroxidation products, the F(2)-isoprostanes, are useful biomarkers that could potentially be utilized as indicators of CHD.

Cross-sectional study of biomarkers of exposure and biological effect on monozygotic twins discordant for smoking

BACKGROUND

The aim of this study was to investigate the possible correlation between smoking status and biomarkers of exposure (BoE) and biological effect (BoBE) in monozygotic twins discordant for smoking status (smoker and non-smoker pairs). By eliminating potential genetic variability in this manner, a clearer pattern of the effects of lifestyle and environmental exposures should become apparent.

METHODS

This was a cross-sectional study on monozygotic healthy twins (44 subjects, 26 males and 18 females) with a mean age 31.5 years. BoE to cigarette smoke and BoBE were measured in body fluids (24 h urine and blood) after medical pre-screening.

RESULTS

All BoE were significantly higher in the smoker twins. Among BoBE, 11-dehydrothromboxane B(2) (11-dehydro TBX), 2,3-dinorthromboxane B(2) (2,3-dinor TBX), 8-epi-prostaglandin F2α (8-epiPGF), hydroxyproline (OH-P), fibrinogen, white blood cell (WBC), neutrophil and lymphocyte counts and heart rate were statistically significantly increased in the smoker compared to the non-smoker twins. Moreover, statistically significant correlations between neutrophil count and 11-dehydro TBX (r=0.32), WBC and 8-epiPGF (r=0.33), OH-P and 8-epiPGF (r=0.49) and heart rate and fibrinogen (r=0.46) were observed.

CONCLUSIONS

The study results confirmed the reliability of the BoE for the evaluation of smoking status. Moreover, a subset of the BoBE, reported as being associated with inflammatory conditions and early stages of vascular disorders, has emerged as showing a consistent relationship with smoking status from the present and the previous studies. By using monozygotic twin pairs, genetic variability has been excluded as a possible source of variability in this study. These results should assist in the interpretation of other population studies using these biomarkers.

Clinical importance of aspirin and clopidogrel resistance

Aspirin and clopidogrel are important components of medical therapy for patients with acute coronary syndromes, for those who received coronary artery stents and in the secondary prevention of ischaemic stroke. Despite their use, a significant number of patients experience recurrent adverse ischaemic events. Interindividual variability of platelet aggregation in response to these antiplatelet agents may be an explanation for some of these recurrent events, and small trials have linked "aspirin and/or clopidogrel resistance", as measured by platelet function tests, to adverse events. We systematically reviewed all available evidence on the prevalence of aspirin/clopidogrel resistance, their possible risk factors and their association with clinical outcomes. We also identified articles showing possible treatments. After analyzing the data on different laboratory methods, we found that aspirin/clopidogrel resistance seems to be associated with poor clinical outcomes and there is currently no standardized or widely accepted definition of clopidogrel resistance. Therefore, we conclude that specific treatment recommendations are not established for patients who exhibit high platelet reactivity during aspirin/clopidogrel therapy or who have poor platelet inhibition by clopidogrel.

Applying tobacco carcinogen and toxicant biomarkers in product regulation and cancer prevention

Tobacco carcinogen and toxicant biomarkers are metabolites or protein or DNA adducts of specific compounds in tobacco products. Highly reliable analytical methods, based mainly on mass spectrometry, have been developed and applied in large studies of many of these biomarkers. A panel of tobacco carcinogen and toxicant biomarkers is suggested here, and typical values for smokers and nonsmokers are summarized. This panel of biomarkers has potential applications in the new and challenging area of tobacco product regulation and in the development of rational approaches to cancer prevention by establishing carcinogen and toxicant uptake and excretion in people exposed to tobacco products.