Oxidant/antioxidant imbalance in smokers and chronic obstructive pulmonary disease

Smoking affects eotaxin levels in asthma patients

BACKGROUND

Chronic airway inflammation is most important pathological finding in asthma. Cigarette smoking may modify type of inflammation as well as may influence disease severity and response to the treatment.

OBJECTIVE

Thus the aim of this study was to investigate whether cigarette smoking may have an influence on the levels of eotaxin-1, eotaxin-2, eotaxin-3 and IL-5 in patients with stable mild/moderate asthma.

METHODS

45 steroid naive asthmatics (mean age: 55.2 +/- 2.2 yrs) and 23 "healthy" smokers and non-smokers control subjects (mean age: 54.4 +/- 9.7 yrs) were investigated. Asthmatics were divided into two subgroups according to their smoking histories: asthmatic smokers (n = 19) who currently smoke and have a history of > 10 pack-years and asthmatic never-smokers (n = 26). BAL and induced sputum were performed. Cytospins of induced sputum and BAL were stained with May-Grunwald-Giemsa for differential cell counts. Eotaxin-1, eotaxin-2, eotaxin-3 and IL-5 concentrations in serum, sputum and BAL supernatant was measured using a commercial ELISA kit.

RESULTS

In sputum supernatant from asthma smokers was significantly higher concentration of eotaxin-1 than in non-smokers asthmatics (203.4 +/- 10.0 vs. 140.2 +/- 9.5 respectively, p < 0.05). In non-smokers asthma patients levels of BAL eotaxin-1 strongly related to percent and absolute numbers of BAL eosinophils and neutrophils (Rs = 0.737 and Rs = 0.514 respectively, p < 0.05). The number and percent of sputum neutrophils and eosinophils, obtained from smokers asthmatics, significantly correlated with eotaxin-2 concentration in sputum supernatant (Rs = 0.58 and Rs = 0.75 respectively, p < 0.05). IL-5 levels in the serum and sputum from asthmatic never-smokers were significantly higher than they were from asthmatic smokers and "healthy" smokers. Asthmatic never-smokers showed a significantly higher amount of IL-5 in serum and sputum than the asthmatic smokers showed.

CONCLUSIONS

This study showed the elevated levels of sputum eotaxin-1 as well as serum, sputum and BAL eotaxin-2 in asthmatic smokers without a significant increase of eosinophils compared to asthmatic never-smokers. The eotaxin concentrations were related not only with number of eosinophils but also with the number of neutrophils in all the studied tissue compartments. The data herein permits a suggestion that smoking may influence change in asthmatic airway inflammation by stimulating the production of eotaxins.

Erdosteine: its relevance in COPD treatment

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a progressive condition characterized by airflow limitation, which is largely irreversible; the oxidant/antioxidant imbalance is important in the pathogenesis of this condition.

OBJECTIVE

To show that administration of erdosteine, a mucolytic agent with a prevalent antioxidant activity, could play a beneficial role in COPD.

METHODS

To review the experimental and clinical trials on erdosteine in COPD and chronic bronchitis.

RESULTS

Erdosteine is a thiol agent with a multifactorial mechanism of action, namely: mucolytic, antibacterial, antioxidant and anti-inflammatory activity. In the acute exacerbation of chronic bronchitis/COPD, addition of erdosteine 300 mg twice a day for 7 - 10 days to standard treatment improves the symptoms and reduces the time of disease. In clinically stable COPD, long-term treatment is associated with a reduction in acute exacerbation and hospitalization rate and a significant improvement of quality of life. Erdosteine could be most beneficial in patients who have repeated, prolonged or severe exacerbations of COPD.

alpha,beta-Unsaturated aldehydes contained in cigarette smoke elicit IL-8 release in pulmonary cells through mitogen-activated protein kinases

Cigarette smoking is the major risk factor for chronic obstructive pulmonary disease (COPD), a syndrome characterized by pulmonary neutrophil infiltration, chronic inflammation, and progressive tissue destruction. We examined here the acute effect of aqueous cigarette smoke extract (CSE) and of two alpha,beta-unsaturated aldehydes (acrolein and crotonaldehyde) contained in CSE in cultured normal human lung fibroblasts and small airway epithelial cells. By examining a panel of 19 cytokines and chemokines, we found that IL-8 release was elevated by CSE as well as by acrolein, whereas other inflammatory mediators were mostly unaffected. CSE-evoked IL-8 release was mimicked by acrolein and crotonaldehyde at concentrations (3-60 microM each) found in CSE and fully prevented by 1 mM alpha,beta-unsaturated aldehydes scavengers N-acetylcysteine (NAC) or sodium 2-mercaptoethanesulfonate. Neither the saturated aldehyde acetaldehyde nor H(2)O(2) evoked IL-8 release. In addition, CSE or crotonaldehyde upregulated the release of IL-8 from alveolar macrophages from both COPD patients and healthy nonsmokers, indicating that this is a response common to cells involved in lung inflammation. CSE-evoked IL-8 release was accompanied by increased phosphorylation of p38 MAPK and ERK1/2. CSE-evoked p38 and ERK1/2 phosphorylation was mimicked by acrolein and inhibited by NAC. IL-8 release elicited by both acrolein and CSE was blocked by pharmacological inhibition of p38 and ERK1/2 phosphorylation. In summary, our data show that alpha,beta-unsaturated aldehydes-evoked phosphorylation of p38 and ERK1/2 underlies IL-8 release elicited by CSE, thus shedding light on the mechanisms through which cigarette smoke can initiate inflammation in the lung.

The Association of Smoking with Components of the Metabolic Syndrome in Non-diabetic Patients

Introduction: There is limited evidence about the association between smoking and metabolic syndrome (MS). The aim of this study was to assess the association of smoking with MS components. Materials and Methods: As part of the baseline survey of a community-based study, we studied 5573 non-diabetic men. All participants were interviewed and underwent physical examinations and blood collection. Results: The study participants comprised 1625 smokers and 3948 non-smokers, with a mean age of 38.07 ± 14.85 years. Serum low-density lipoproteincholesterol (LDL-C) and triglycerides (TG) were higher in smokers than in non-smokers (LDLC: 115.34 ± 39.03 vs 112.65 ± 40.94 mg/dL, respectively, P = 0.015 and TG: 175.13 ± 102.05 vs 172.32 ± 116.83 mg/dL, respectively, P = 0.005). Body mass index, waist circumference and waisthip ratio were lower in smokers than in non-smokers. Mean systolic and diastolic blood pressures were significantly lower in smokers than in non-smokers (systolic: 112.06 ± 15.888 vs 117.25 ± 17.745 mmHg, respectively, P = 0.000; diastolic: 73.66 ± 10.084 vs 76.23 ± 10.458 mmHg, respectively, P = 0.000). The percentage of individuals with 2 MS components was higher in smokers than in non-smokers (39.64% vs 33.00%, respectively, P = 0.000). However, the percentage of non-smokers with 3 MS components was higher than in smokers (49.62 % vs 43.82%, respectively, P = 0.000). Conclusions: Our findings support the hypothesis that lifestyle factors such as smoking can adversely affect MS components. However, we should acknowledge that these differences may have resulted from the large sample sizes studied and may not be clinically significant. The lower prevalence of some MS components in smokers than in nonsmokers might be because of their lower anthropometric measures. Key words: Anthropometric indexes, Biochemical factors

Oxidative stress is an important component of airway inflammation in mice exposed to cigarette smoke or lipopolysaccharide

1. It was proposed previously that oxidative stress is a main component of the inflammatory process in chronic obstructive pulmonary disease (COPD). Thus, in the present study, we investigated the inflammatory response in mice deficient for the p47(phox) subunit of NADPH oxidase (p47 KO) exposed to cigarette smoke (CS). 2. Exposure of mice to CS elicited an increase in the number of macrophages and neutrophils and levels of interleukin (IL)-6, keratinocyte-derived chemokine (KC/CXCL1) and monocyte chemoattractant protein-1 (MCP1/CCL2) in bronchoalveolar lavage fluid (BALF), which were lower in p47 KO mice compared with control mice. In contrast, 24 h after lipopolysaccharide (LPS) exposure, the number of macrophages and neutrophils, as well as KC/CXCL1 levels, in BALF was significantly greater in p47 KO mice compared with control mice. 3. The present study has shown that airway inflammation is decreased in p47 KO mice after exposure to CS, but not LPS, suggesting that oxidative stress is involved in the pathogenesis of airway inflammation associated with COPD.

Cells, mediators and Toll-like receptors in COPD

Chronic obstructive pulmonary disease (COPD) is a global health problem. Being a progressive disease characterized by inflammation, it deteriorates pulmonary functioning. Research has focused on airway inflammation, oxidative stress, and remodelling of the airways. Macrophages, neutrophils and T cells are thought to be important key players. A number of new research topics received special attention in the last years. The combined use of inhaled corticosteroids and long-acting beta(2)-adrenoceptor agonists produces better control of symptoms and lung function than that of the use of either compound alone. Furthermore, collagen breakdown products might be involved in the recruitment and activation of inflammatory cells by which the process of airway remodelling becomes self-sustaining. Also, TLR (Toll-like receptor)-based signalling pathways seem to be involved in the pathogenesis of COPD. These new findings may lead to new therapeutic strategies to stop the process of inflammation and self-destruction in the airways of COPD patients.

Maternal active or passive smoking causes oxidative stress in cord blood

The aim of this study was to assess the influence of active and passive maternal smoking on cord blood total oxidant/antioxidant status at term. The levels of cord blood catalase (CAT), paraoxonase 1 (PON1), ceruloplasmin, total thiol and lipid hydroperoxide (LOOH), total antioxidant capacity (TAC), total oxidant status (TOS) and the oxidative stress index (OSI) were measured in samples of fetal cord blood serum from 29 nonsmokers who were not exposed to active or passive smoke, 30 passive smokers and 21 active smokers. The gestation period of all pregnancies was between 37 and 40 weeks, the pregnancies were uncomplicated and the infants were delivered vaginally. The weights of infants borne to the active smokers were significantly (P < 0.01) lower than those borne to the controls. Significantly lower concentrations of CAT, PON1 and TAC were found in the cord blood of the smokers than in that of the nonsmokers (P < 0.018). The cord blood levels of LOOH and TOS and OSI were significantly higher in the active and passive smokers than in the controls (P < 0.01). A significant positive correlation was found between maternal tobacco exposure and cord blood OSI (P < 0.001). Active or passive maternal smoking is associated with important alterations in the balance of oxidants and antioxidants in fetal cord blood and causes potent oxidative stress.

Antioxidant therapies in COPD

Oxidative stress is an important feature in the pathogenesis of COPD. Targeting oxidative stress with antioxidants or boosting the endogenous levels of antioxidants is likely to be beneficial in the treatment of COPD. Antioxidant agents such as thiol molecules (glutathione and mucolytic drugs, such as N-acetyl-L-cysteine and N-acystelyn), dietary polyphenols (curcumin, resveratrol, green tea, catechins/quercetin), erdosteine, and carbocysteine lysine salt, all have been reported to control nuclear factor-kappaB (NF-κ B) activation, regulation of glutathione biosynthesis genes, chromatin remodeling, and hence inflammatory gene expression. Specific spin traps such as α-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (ECSOD mimetic), porphyrins (AEOL 10150 and AEOL 10113), and a superoxide dismutase mimetic M40419 have also been reported to inhibit cigarette smoke-induced inflammatory responses in vivo. Since a variety of oxidants, free radicals, and aldehydes are implicated in the pathogenesis of COPD, it is possible that therapeutic administration of multiple antioxidants will be effective in the treatment of COPD. Various approaches to enhance lung antioxidant capacity and clinical trials of antioxidant compounds in COPD are discussed.

Role of mucolytics in the management of COPD

There is, to date, no medical therapy that modifies the decline in lung function that occurs in COPD. As the disease becomes more severe, exacerbations of COPD become increasingly common, affecting patient quality of life and increasing health care costs. Mucolytic agents, through their actions on inflammatory and oxidative pathways, have potential benefits in COPD. This paper reviews the randomized controlled trial (RCT) evidence for the effectiveness of at least 2 months of daily therapy with oral mucolytics in COPD. Based on evidence from 26 RCTs, mucolytics reduce exacerbations by up to 0.8 exacerbations per year, with a greater effect in patients with more severe COPD. This effect appears to be of a similar magnitude to the reduction in exacerbations seen with tiotropium and inhaled corticosteroids (ICS), but RCTs that compared the agents would be required to confirm this. Mucolytics do not affect the rate of lung function decline, but they do not have any significant adverse effects. Mucolytic treatment should be considered in: patients with more severe COPD who have frequent or prolonged exacerbations; those who are repeatedly admitted to hospital; or in those patients with frequent exacerbations who are unable to take tiotropium or ICS.

Correlation of oxidative status with BMI and lung function in COPD

OBJECTIVES

The imbalance in oxidative status together with nutrition depletion and low body weight play a vital role in the pathogenesis and severity of chronic obstructive pulmonary disease (COPD). The study was undertaken to ascertain if a relationship existed between oxidative status and BMI in COPD. In addition, association of oxidative status and BMI with lung function of the disease was also examined.

MATERIALS AND METHODS

In 202 COPD patients and 136 healthy controls plasma lipid peroxidation (LPO), reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT) activities, BMI and FEV(1)% predicted were looked for interactions.

RESULTS

The patients had increased LPO (p=0.006) and decreased antioxidants (GSH, p=0.005; GPx, p=0.035 and CAT, p=0.008, respectively). Of note are the correlations of oxidative stress markers with BMI and FEV(1)% predicted in the patients. LPO inversely and GSH, GPx, and CAT positively correlated with both BMI (p=0.007, p<0.001, p=0.045 and p=0.009, respectively), and FEV(1)% of predicted (LPO, p=0.001; GSH, p<0.001; GPx, p=0.043 and CAT, p<0.001) in the patients. Further, a positive correlation existed between BMI and FEV(1)% predicted (p=0.016) in COPD.

CONCLUSION

The intimate relationship of oxidative status with BMI and lung function, and the direct correlation between BMI and FEV(1) may potentiate severity of the disease.

Effect of cigarette smoking on the oxidant/antioxidant balance in healthy subjects

BACKGROUND AND PURPOSE

Cigarette smoking has been associated with the development of cardiovascular disease and cancer. Even though the molecular mechanism(s) are not clear, the pathology has been related to oxygen free radicals present in cigarette smoke. Thus, the main objective of this study was to establish the changes in the oxidation/antioxidation balance induced by cigarette smoking.

METHODS

Thirty healthy subjects (15 smokers and 15 nonsmokers) of both sexes were studied. The smokers group had smoked a mean of 14 cigarettes per day for an average of 4.5 years. Fasting serum levels of malondialdehyde (MDA), a marker of oxidative stress, nitric oxide (NO), reduced glutathione (GSH), and vitamin C (ascorbic and dehydroascorbic acids) were measured.

RESULTS

Fasting NO concentration was significantly higher in smokers (51.3 +/- 5.3 microM) than in nonsmokers (35.2 +/- 4.8 microM, P < 0.05). The smokers had significantly higher serum dehydroascorbic acid levels (2.4 +/- 0.5 mg/dL, P < 0.03) than the nonsmokers (1.08 +/- 0.08 mg/dL). No significant differences were observed in the levels of ascorbic acid, MDA, and GSH between the smokers and nonsmokers.

CONCLUSIONS

Our results suggest that exposure to cigarette smoke increases NO synthesis, such that NO may act in a compensatory way as an inhibitor of lipid peroxidation. Smoking also activates other antioxidative mechanisms such as involving vitamin C. These protective mechanisms appear to be enough in preventing accumulation of oxidative products such as MDA and avoiding oxidative damage.

Genetic polymorphisms of GSTP1 and mEPHX correlate with oxidative stress markers and lung function in COPD

The genetic susceptibility to COPD might depend on variations in detoxification enzymes that activate and detoxify cigarette smoke products, which otherwise generate oxidative stress causing pathogenesis. In a case-control study of 202 COPD patients and 136 normals, we examined the association of polymorphisms I105V, A114V of GSTP1 and Y113H, H139R of mEPHX individually or in combination with disease and their contribution to oxidative stress markers such as MDA, GSH, GPx and airflow obstruction. Patients were over-represented by the alleles 105V, 114V of GSTP1 and 113H, 139H of mEPHX (chi(2)=10.63, p=0.001, chi(2)=13.92, p<0.001, chi(2)=13.02, p<0.001 and chi(2)=4.48, p=0.034, respectively) and the haplotypes of same alleles i.e. 105V-114V and 113H-139H (chi(2)=14.58, p<0.001 and chi(2)=23.14, p<0.001). Moreover, there was marked over-representation of combination of genotypes, I105I+A114A of GSTP1 (53% vs. 36%) in controls; whereas, the combinations with 105V/114V alleles (64% vs. 47%) of GSTP1 (OR=1.99; 95% CI=1.28-3.09; p=0.002) and the homozygotes H113H+H139H (27% vs.10%) of mEPHX (OR=3.26; 95% CI=1.73-6.15; p=0.0001) in patients. Patients had significantly elevated MDA level (p<0.001) and decreased GSH level (p<0.001) and GPx activity (p=0.035), respectively. Of note, the genotypes, I105V/V105V, A114V/V114V of GSTP1 and Y113H/H113H of mEPHX associated with increased MDA level (p=0.04, p=0.03 and p=0.003), decreased GSH level (p=0.019, p=0.007 and p=0.0006) and lower FEV1 (p=0.23, p=0.037 and p=0.029), respectively, in patients; so was the correlation of these biomarkers and lung function with the combinations of the genotypes. In conclusion, 105V/114V alleles of GSTP1 and 113H/139H alleles of mEPHX and the combination of genotypes with same alleles associated with imbalanced oxidative stress and lung function in patients, signifying the importance in the disease.

Airway reactivity to inhaled mannitol in cigarette smokers: a longitudinal study

Smoking induces airway hyperresponsiveness (AHR). Bronchial provocation with mannitol is used to identify AHR in subjects with asthma. This study aimed to determine the prevalence of airway hyperresponsiveness to mannitol in asymptomatic smokers compared to non-smokers and to assess if airway responsiveness to mannitol changes after smoking cessation. Airway responsiveness to inhaled mannitol was measured in smokers (n=42), and non-smokers (n=45). In smokers, the mannitol test was repeated 3 months after smoking cessation. Demographics including age, lung function and atopy status were similar for smokers and non-smokers (p=ns). Compared with non-smokers (2.2%), AHR to mannitol expressed by 15%> or = fall in FEV(1) was significantly more common in smokers (26.2%) (p=0.001). The provoking dose to induce a 15%> or = fall in FEV(1) (PD(15)), a measure of sensitivity, was median [IQR] 291 mg [207-377] in the 11 positive smokers. The response-dose ratio (RDR) (% fall in FEV(1)/cumulative dose), a measure of reactivity, was significantly higher in smokers (0.013 [0.006-0.029]) compared with non-smokers (0.004 [0.002-0.007]), (p<0.0001). After successful smoking cessation, the RDR decreased in most cases (p=0.01) and only one patient still recorded a 15% fall in FEV(1). None of the patients with a negative mannitol test turned positive, irrespective of the outcome of smoking cessation. AHR to mannitol is quite common in smokers compared to non-smokers and decreases significantly after smoking cessation. Thus, the mannitol test may be sensitive to non-asthmatic inflammation of the airways.

Future therapeutic treatment of COPD: struggle between oxidants and cytokines

Chronic obstructive pulmonary disease (COPD) is a global health problem. Being a progressive disease characterized by inflammation and predominantly caused by tobacco smoking, it deteriorates pulmonary and skeletal muscle functioning, and reduces physical behavior, societal participation and quality of life. During the last two decades studies were focused on the airway and systemic inflammation, oxidative stress, and airway and/or parenchymal remodeling. Macrophages, neutrophils and T cells are thought to be important key players, as well as structural cells like fibroblasts, epithelial, endothelial and smooth muscle cells. Mediators and proteins including cytokines, chemokines, growth factors, proteinases, and oxidants seem to be involved differentially in its pathogenesis. Current pharmacological treatments are directed to reducing airway inflammation, boosting the endogenous levels of anti-oxidants and relieving airway contraction and sputum production. Most agents were primarily used for treating asthma. But in contrast to asthma, these treatments are not very effective in COPD. As a result, novel more specifically acting interventional drugs with less side effects are being developed to treat chronic inflammatory diseases, including COPD. This review highlights studies on novel or potential drug antioxidants such as dietary antioxidants supplementation, N-acetyl-L-cysteine, N-acystelyn, endosteine, antioxidant enzyme mimetics, and anti-inflammatory agents like antagonists of cytokines, such as tumor necrosis factor (TNF)-alpha, CXCL8, and CCL2, and inhibitors of signal transduction proteins including phosphodiesterase 4, MAPK p38, P1-3k, and NFkappaB.

Migrating leukocytes are the source of peroxiredoxin V during inflammation in the airways

Background

We characterized changes in expression of the antioxidant protein Peroxiredoxin V (PRXV) during airway inflammation.

Methods

Studies in anesthetized rats and mice; PRXV expression determined by Western blot analyses and immunohistochemistry; PRXV m-RNA expression determined by Taq-Man RT-PCR.

Results

Bacterial lung inflammation did not change expression of PRXV in murine epithelia but produced massive influx of leukocytes highly expressing PRXV. Endotoxin and f-MLP induced leukocyte migration in rat trachea but did not change mRNA levels and PRXV protein expression in tracheal epithelial cells. In primary airway cell culture (cow), alveolar epithelial cells A549, or co-culture of A549 with murine macrophages RAW264.7, exposure to live bacteria increased expression of PRXV, which required serum. PRXV was secreted in vitro by epithelial and immune cells.

Conclusion

Inflammation increased expression of PRXV in airways by at least 2 mechanisms: cell population shift by massive influx of leukocytes expressing PRXV, and moderate post-transcriptional up-regulation of PRXV in epithelial cells.

Cigarette smoke synergistically enhances respiratory mucin induction by proinflammatory stimuli

Pathogenic factors associated with chronic obstructive pulmonary disease (COPD), such as cigarette smoke, proinflammatory cytokines, and bacterial infections, can individually induce respiratory mucins in vitro and in vivo. Since co-presence of these factors is common in lungs of patients with COPD, we hypothesized that cigarette smoke can amplify mucin induction by bacterial exoproducts and proinflammatory cytokines, resulting in mucin hyperproduction. We demonstrated that cigarette smoke extract (CSE) synergistically increased gene expression and protein production of MUC5AC mucin induced by LPS or TNF-alpha in human airway epithelial NCI-H292 cells. CSE also enhanced expression and production of MUC5AC mucin induced by epidermal growth factor receptor (EGFR) ligands TGF-alpha and amphiregulin, as well as LPS- and TNF-alpha- induced expression and/or release of TGF-alpha and amphiregulin. Furthermore, (4-[(3-bromophenyl)amino]-6,7-diaminoquinazoline), a potent inhibitor of EGFR, blocked synergistic induction of MUC5AC mucin. H(2)O(2) mimicked the synergistic effects of CSE, while antioxidant N-acetyl-L-cysteine prevented synergistic induction of MUC5AC mucin by CSE. In a rat model of LPS-induced airway inflammation, concurrent cigarette smoke inhalation enhanced mucin content of the bronchoalveolar lavage fluid, muc5AC gene expression, and mucous cell metaplasia in the airways. These results suggest that cigarette smoke has the potential to synergistically amplify induction of respiratory mucins by proinflammatory stimuli relevant to COPD pathogenesis and contribute to mucin hyperproduction observed in patients with COPD.

Differential induction of apoptosis by cigarette smoke extract in primary human lung fibroblast strains: implications for emphysema

Cigarette smoke is the principal cause of emphysema. Recent attention has focused on the loss of alveolar fibroblasts in the development of emphysema. Fibroblasts may become damaged by oxidative stress and undergo apoptosis as a result of cigarette smoke exposure. Not all smokers develop lung diseases associated with tobacco smoke, a fact that may reflect individual variation among human fibroblast strains. We hypothesize that fibroblasts from different human beings vary in their ability to undergo apoptosis after cigarette smoke exposure. This could account for emphysematous changes that occur in the lungs of some but not all smokers. Primary human lung fibroblast strains were exposed to cigarette smoke extract (CSE) and assessed for viability, morphological changes, and mitochondrial transmembrane potential as indicators of apoptosis. We also examined the generation of intracellular reactive oxygen species (ROS), 4-hydroxy-2-nonenal, and changes in glutathione (GSH) and glutathione disulfide (GSSG) levels. Each human lung fibroblast strain exhibited a differential sensitivity to CSE as judged by changes in mitochondrial membrane potential, viability, ROS generation, and glutathione production. Interestingly, the thiol antioxidants N-acetyl-L-cysteine and GSH eliminated CSE-induced changes in fibroblast morphology such as membrane blebbing, nuclear condensation, and cell size and prevented alterations in mitochondrial membrane potential and the generation of ROS. These findings support the concept that oxidative stress and apoptosis are responsible for fibroblast death associated with exposure to tobacco smoke. Variations in the sensitivity of fibroblasts to cigarette smoke may account for the fact that only some smokers develop emphysema.

Global Initiative on Obstructive Lung Disease (GOLD) classification of lung disease and mortality: findings from the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

To determine whether a modified Global Initiative on Obstructive Lung Diseases (GOLD) classification of chronic obstructive pulmonary disease (COPD) predicts mortality in a cohort of subjects followed for up to 11 years.

METHODS

We analyzed data from 15,759 adult participants, aged 43-66 years at baseline, in the Atherosclerosis Risk in Communities (ARIC) study. All baseline and follow-up data were available for 15,440 (97.9%) of the initial participants. We classified subjects using a modification of the GOLD criteria for COPD (prebronchodilator forced expiratory volume in 1s (FEV(1)) stratification of disease severity), and added a "restricted" category (FEV(1)/FVC>70% and FVC<80% predicted). We used Cox proportional hazard models to determine the risk of impaired lung function on subsequent mortality, after adjusting for age, race, sex and smoking status.

RESULTS

1242 (8.0%) subjects died by the end of 1997. The overall rate of death was 8.9 per 1000 person years, but varied from 5.4/1000 among normal subjects to 42.9/1000 among subjects with GOLD Stage 3 or 4 COPD. After adjusting for covariates, all GOLD categories, along with the restricted category, predicted a higher risk of death: GOLD Stage 3 or 4, hazard ratio (HR) 5.7, 95% confidence interval (CI) 4.4, 7.3; GOLD Stage 2 HR 2.4, 95% CI 2.0, 2.9; GOLD Stage 1 HR 1.4, 95% CI 1.1, 1.6; GOLD Stage 0 HR 1.5, 95% CI 1.3, 1.8; and restricted HR 2.3, 95% CI 1.9, 2.8.

CONCLUSION

The modified GOLD classification system of COPD predicts mortality in this cohort of middle-aged Americans followed for up to 11 years.

Oxidant–Antioxidant Balance in Patients with COPD

The goal of this study was to evaluate the role of oxidant-antioxidant balance in the pathogenesis of COPD. We included 30 healthy nonsmokers [24 male, 6 female; mean age (yr) +/- SD: 62.4 +/- 9.3], 30 healthy smokers [27 male, 3 female; mean age (yr) +/- SD: 58.7 +/- 6.0], 71 patients with stable COPD [68 male, 3 female; mean age (yr) +/- SD: 63.5 +/- 7.9], and 31 patients with COPD exacerbation [30 male, 1 female; mean age (yr) +/- SD: 64.2 +/- 7.3]. In all study groups the peripheral venous blood samples were taken for plasma malonyldialdehyde (MDA), a parameter of lipid peroxidation caused by the oxidants, and erythrocyte superoxide dismutase (SOD), an antioxidant enzyme. The mean plasma MDA level was higher in healthy smokers and in patients with COPD than in healthy nonsmokers (p < 0.05), and erythrocyte SOD enzyme activity in patients with COPD exacerbation (1048.2 +/- 226.5 Ug/Hb) was significantly higher than in healthy nonsmokers (947.9 +/- 198.0 Ug/Hb) (p < 0.05). Although mean erythrocyte SOD enzyme activity in healthy smokers and patients with stable COPD was higher than in healthy nonsmokers, the difference was not statistically significant. We found that healthy smokers and stable and exacerbated COPD patients had an impairment in oxidant-antioxidant balance. We suggested that new therapeutic interventions, which may repair the impaired oxidant-antioxidant balance in COPD, are needed to prevent the development of COPD.

Vitamins and respiratory disease: antioxidant micronutrients in pulmonary health and disease

The lungs are continually exposed to relatively-high O(2) tensions, and as such, in comparison with other organs, they represent a unique tissue for the damaging effects of oxidant attack. At particular times during a lifetime this every day challenge may increase exponentially. The first oxidative insult occurs at birth, when cells are exposed to a sudden 5-fold increase in O(2) concentration. Thereafter, the human lung, from infancy through to old age, can be subjected to deleterious oxidative events as a consequence of inhaling environmental pollutants or irritants, succumbing to several pulmonary diseases (including infant and adult respiratory distress syndromes, asthma, chronic obstructive pulmonary disease, cystic fibrosis and cancer) and receiving treatment for these diseases. The present paper will review the concept that consumption of a healthy diet and the consequent ability to establish and then maintain adequate micronutrient antioxidant concentrations in the lung throughout life, and following various oxidative insults, could prevent or reduce the incidence of oxidant-mediated respiratory diseases. Furthermore, the rationale, practicalities and complexities of boosting the antioxidant pool of the respiratory-tract lining fluid in diseases in which oxidative stress is actively involved, by direct application to the lung v. dietary modification, in order to achieve a therapeutic effect will be discussed.

Oxygen therapy at low flow causes oxidative stress in chronic obstructive pulmonary disease: Prevention by N-acetyl cysteine

Exposure to high oxygen concentration produces toxicity by free radical release. We aimed to study: whether stable chronic obstructive pulmonary disease (COPD) patients present an unbalance in the blood redox status; the effect of oxygen administration on blood redox balance; the efficacy of N-acetyl-cysteine (NAC) treatment against the oxidative stress-induced by oxygen administration and whether it is dose-related. To this, 45 stable state III COPD patients were recruited and reduced glutathione (GSH) and oxidised glutathione (GSSG) in erythrocytes and thiol proteins (P-SH) and carbonyl proteins (PC) in both erythrocytes and plasma were evaluated. All COPD patients underwent 2 l/m oxygen for 18 h and NAC at 1200 or 1800 mg/day or placebo for 48 h starting with oxygen administration. Blood samples were collected at basal conditions, after 8 and 18 h of oxygen administration and 24 h after oxygen withdrawal.

RESULTS

COPD patients present an unstable redox equilibrium mainly due to plasma sulphydryl protein depletion. Oxygen administration oxidize erythrocyte GSH, decrease P-SH and increase PC levels in both plasma and erythrocytes. NAC administration counteract the oxidative stress and at the highest dose completely prevent protein oxidation. In conclusion, stable state III COPD patients present an unstable redox balance; long term low flow oxygen administration induces systemic oxidative stress, which is prevented by NAC treatment.

Cigarette smoke-induced emphysema: A role for the B cell?

RATIONALE

Little is known about what drives the inflammatory reaction in the development of chronic obstructive lung disease. B cells have been found.

OBJECTIVE

To study the involvement of B cells in the development of emphysema.

METHODS

The presence of B-cell follicles and their interaction with other cells were investigated in lungs of patients with chronic obstructive pulmonary disease and of smoking mice. B cells were isolated from lymphoid follicles by laser microdissection and analyzed for the presence of immunoglobulin rearrangements and somatic mutations.

MAIN RESULTS

Lymphoid follicles consisting of B cells and follicular dendritic cells with adjacent T cells were demonstrated both in the parenchyma and in bronchial walls of patients with emphysema. A clonal process was observed in all follicles and the presence of ongoing somatic mutations was observed in 75% of the follicles, indicating oligoclonal, antigen-specific proliferation. Similar lymphoid follicles were detected in mice that had developed pulmonary inflammation and progressive alveolar airspace enlargement after smoking. The increase in the number of B-cell follicles was progressive with time and correlated with the increase in mean linear intercept. Specific bacterial or viral nucleic acids could not be detected.

CONCLUSIONS

B-cell follicles with an oligoclonal, antigen-specific reaction were found in men and mice with emphysema. In mice, the development was progressive with time and correlated with the increase in airspace enlargement. We hypothesize that these B cells contribute to the inflammatory process and/or the development and perpetuation of emphysema by producing antibodies against either tobacco smoke residues or extracellular matrix components.

Cigarette smoke extract inhibits expression of peroxiredoxin V and increases airway epithelial permeability

Inhaled cigarette smoke induces oxidative stress in the epithelium of airways. Peroxiredoxin V (PRXV) is a potent antioxidant protein, highly expressed in cells of the airway epithelium. The goal of our study was to determine whether cigarette smoke extract (CSE) influenced expression of this protein in airway epithelia in vivo and in vitro. In Sprague-Dawley rats, we determined effects of CSE on airway epithelial permeability, mRNA levels and expression of PRXV protein. Exposure of isolated tracheal segment in vitro to 20% CSE for 4 h resulted in development of increased permeability to albumin, significantly reduced mRNA levels for PRXV, and reduced amounts of PRXV protein in the epithelium. In cultures of the airway epithelial cell lines (Calu-3, JME), primary airway cell culture (cow), and alveolar epithelial cells A549, CSE also significantly decreased transepithelial electrical resistance and expression of PRXV protein, and induced glutathione and protein oxidation. To demonstrate functional importance of PRXV, we exposed clones of HeLa cells with siRNA-downregulated PRXV to hydrogen peroxide, which resulted in increased rate of cell death and protein oxidation. CSE directly downregulates expression of functionally important antioxidant enzyme PRXV in the epithelial cells of airways, which represents one pathophysiological mechanism of cigarette smoke toxicity.

Decreased total antioxidant capacity and increased oxidative stress in passive smoker infants and their mothers

BACKGROUND

Smoking has many adverse health effects in infants and adults. The purpose of the study was to study the effect of passive cigarette smoking on oxidative and antioxidative status of plasma in passive smoker infants and their mothers and to compare with those of non-smokers.

METHODS

Subjects were randomly chosen from infants aged 8-26 weeks and their mothers aged 20-34 years. Passive smoker infants (n = 29) and their mothers (n = 29) were defined as having other family members who smoked six or more cigarettes per day continually for at least 8 weeks. Non-smokers were defined as infants (n = 30) and their mothers (n = 24) who had never been exposed to passive smoking. The antioxidative status of plasma were perused by measuring the total antioxidant capacity. Oxidative status was evaluated by predicating total peroxide level, oxidative stress index, protein oxidation and lipid peroxidation.

RESULTS

Plasma concentrations of total antioxidant capacity were significantly lower in passive smoker infants and their mothers than non-passive smoker infants and their mothers. However, lipid peroxidation and oxidative stress index were remarkably higher in passive smoker infants and their mothers than those of non-passive smoker infants and their mothers. There were significant correlations between the oxidative and antioxidative parameters of the passive smoker infants and their mothers.

CONCLUSIONS

Oxidants are increased and antioxidants are decreased in passive smoker infants and their mothers than those of non-smokers. Passive smoker infants and their mothers are exposed to potent oxidative stress.

Increased oxidative stress in infants exposed to passive smoking

The purpose of this study was to assess the effect of passive cigarette smoking on the oxidative and anti-oxidative status of plasma in infants. Eighty-four infants aged 6-28 weeks were divided into two groups: the study group included infants who had been exposed to passive smoking via at least five cigarettes per day for at least the past 6 weeks at home, while the control group included infants who had never been exposed to passive smoking. The antioxidative status of plasma was assessed by the measurement of individual antioxidant components: vitamin C, albumin, bilirubin, uric acid, thiol contents and total antioxidant capacity (TAC 1 and TAC 2). Oxidative status was assessed by the determination of total peroxide levels and the oxidative stress index (OSI 1 and OSI 2). Plasma vitamin C, thiol concentration and TAC 1 and TAC 2 levels were significantly lower, whereas plasma total peroxide levels and OSI 1 and OSI 2 were significantly higher, in passive smoking infants than in the controls (P<0.01). We conclude that passive smoking has a negative impact on numerous parts of the antioxidant defence system in infants, and exposes them to potent oxidative stress.

Baseline pulmonary function and quality of life 9 years later in a middle-aged Chinese population

STUDY OBJECTIVE

This research examined the association of baseline pulmonary function with future quality of life (QOL).

METHODS

We collected baseline pulmonary function data in 1993 and 1994, and assessed QOL using the Chinese 35-Item Quality of Life Instrument in 2002 in a cohort of 1,356 participants. We used Pearson correlation analysis, multivariate analysis of variance, and multivariate linear regression analysis to assess the relationship between pulmonary function and QOL.

RESULTS

The baseline percentage of age- and height-predicted FEV1 (FEV1%) was significantly correlated with the resurvey total QOL score (r = 0.126, p < 0.001) and with QOL scores for the general (r = 0.074, p = 0.006), physical (r = 0.085, p = 0.002), independence (r = 0.178, p < 0.001), and psychological (r = 0.064, p = 0.018) domains but not with the social and environmental domains after adjusting for age and sex. These associations were weaker for the percentage of age- and height-predicted FVC. Multiple linear regression showed that the above associations were independent of baseline and resurvey smoking status. Inclusion of respiratory symptoms in the model reduced the regression coefficients from 0.82 to 0.41 for the total QOL score and from 1.43 to 0.94 for the independence domain score, for a 10% change in FEV1%. The age- and sex-adjusted mean total QOL scores were 78, 76, 76, and 69, respectively (p < 0.001), for the groups of normal, symptomatic only, impaired pulmonary function only, and both symptomatic and impaired pulmonary function. This trend was also significant for the general, physical, independence, and psychological domain scores.

CONCLUSION

Impaired baseline pulmonary function has a significant negative impact on QOL in later life that is independent of age, sex, height, and smoking status and is largely mediated through the development of chronic respiratory symptoms.

Regulation of constitutive neutrophil apoptosis by the alpha,beta-unsaturated aldehydes acrolein and 4-hydroxynonenal

Reactive alpha,beta-unsaturated aldehydes are major components of common environmental pollutants and are products of lipid oxidation. Although these aldehydes have been demonstrated to induce apoptotic cell death in various cell types, we recently observed that the alpha,beta-unsaturated aldehyde acrolein (ACR) can inhibit constitutive apoptosis of polymorphonuclear neutrophils and thus potentially contribute to chronic inflammation. The present study was designed to investigate the biochemical mechanisms by which two representative alpha,beta-unsaturated aldehydes, ACR and 4-hydroxynonenal (HNE), regulate neutrophil apoptosis. Whereas low concentrations of either aldehyde (<10 microM) mildly promoted apoptosis in neutrophils (reflected by increased phosphatidylserine exposure, caspase-3 activation, and mitochondrial cytochrome c release), higher concentrations prevented critical features of apoptosis (caspase-3 activation, phosphatidylserine exposure) and caused delayed neutrophil cell death with characteristics of necrosis/oncosis. Inhibition of caspase-3 activation by either aldehyde occurred despite increases in mitochondrial cytochrome c release and occurred in close association with depletion of cellular GSH and with cysteine modifications within caspase-3. However, procaspase-3 processing was also prevented, because of inhibited activation of caspases-9 and -8 under similar conditions, suggesting that ACR (and to a lesser extent HNE) can inhibit both intrinsic (mitochondria dependent) and extrinsic mechanisms of neutrophil apoptosis at initial stages. Collectively, our results indicate that alpha,beta-unsaturated aldehydes can inhibit constitutive neutrophil apoptosis by common mechanisms, involving changes in cellular GSH status resulting in reduced activation of initiator caspases as well as inactivation of caspase-3 by modification of its critical cysteine residue.

Hypoxaemia enhances peripheral muscle oxidative stress in chronic obstructive pulmonary disease

BACKGROUND

Because oxidative stress affects muscle function, the underlying mechanism to explain exercise induced peripheral muscle oxidative stress in patients with chronic obstructive pulmonary disease (COPD) is clinically relevant. This study investigated whether chronic hypoxaemia in COPD worsens peripheral muscle oxidative stress and whether an abnormal muscle inflammatory process is associated with it.

METHODS

Nine chronically hypoxaemic and nine non-hypoxaemic patients performed repeated knee extensions until exhaustion. Biopsy specimens were taken from the vastus lateralis muscle before and 48 hours after exercise. Muscle oxidative stress was evaluated by lipid peroxidation (lipofuscin and thiobarbituric acid reactive substances (TBARs)) and oxidised proteins. Inflammation was evaluated by quantifying muscle neutrophil and tumour necrosis factor (TNF)-alpha levels.

RESULTS

When both groups were taken together, arterial oxygen pressure was positively correlated with quadriceps endurance time (n = 18, r = 0.57; p < 0.05). At rest, quadriceps lipofuscin inclusions were significantly greater in hypoxaemic patients than in non-hypoxaemic patients (2.9 (0.2) v 2.0 (0.3) inclusions/fibre; p < 0.05). Exercise induced a greater increase in muscle TBARs and oxidised proteins in hypoxaemic patients than in non-hypoxaemic patients (40.6 (9.1)% v 10.1 (5.8)% and 51.2 (11.9)% v 3.7 (12.2)%, respectively, both p = 0.01). Neutrophil levels were significantly higher in hypoxaemic patients than in non-hypoxaemic patients (53.1 (11.6) v 21.5 (11.2) counts per fibre x 10(-3); p < 0.05). Exercise did not alter muscle neutrophil levels in either group. Muscle TNF-alpha was not detected at baseline or after exercise.

CONCLUSION

Chronic hypoxaemia was associated with lower quadriceps endurance time and worsened muscle oxidative stress at rest and after exercise. Increased muscle neutrophil levels could be a source of the increased baseline oxidative damage. The involvement of a muscle inflammatory process in the exercise induced oxidative stress of patients with COPD remains to be shown.

Markers of inflammation and oxidative stress in exacerbated chronic obstructive pulmonary disease patients

COPD is characterised by damage to small airways due to an inflammatory process as well as an imbalance between oxidants and antioxidants. Several cytokines and cell adhesion molecules enhancing a mainly neutrophilic inflammation have been associated with COPD. The aim of the study was to investigate whether inflammation or oxidative markers gave an indication of the course of COPD during an exacerbation. Fourteen patients with moderate to severe COPD admitted to the St. Antonius Hospital because of an exacerbation have been monitored during treatment with prednisolone 50 mg intravenously during 24 h at admission, reduced to 25 mg at day 3 and tapered off with oral prednisolone at day 7. On three separate occasions, day 1, 3 and 7, H2O2 in exhaled air, IL-8 and the soluble cell adhesion molecule sICAM and sE-selectin in serum were measured. We compared the patients at day 1 with healthy controls (in both non-smokers and smokers). Furthermore, we examined the changes from the study group in time during therapy. At admission all the markers were raised in comparison with the control groups. During treatment H2O2 concentrations in breath condensate declined significantly (P<0.001) as well as IL-8 and sICAM in serum (P=0.002, respectively, P<0.001). There was no significant change in sE-selectin (P=0.132). No significant improvement has been found in spirometry. These data suggest that the markers H2O2 in exhaled air, IL-8 and sICAM in serum are suitable markers in monitoring exacerbated COPD.

Glutathione S-Transferase P1 and Lung Function in Patients With α 1 -Antitrypsin Deficiency and COPD

BACKGROUND

The glutathione S-transferase P1 (GSTP1) gene is involved in detoxification of electrophilic substances of tobacco smoke. A polymorphism at nucleotide 315 of this gene alters its enzymatic activity.

OBJECTIVE

We analyzed the association between the variability in the GSTP1 gene and impairment in lung function in smokers with and without alpha(1)-antitrypsin (AAT) deficiency and COPD.

POPULATION AND METHOD

The study population consisted of 99 patients with smoking-related COPD and 69 patients with AAT deficiency; 198 healthy volunteers provided the frequency of the different polymorphisms in the general population. GSTP1 genotyping was performed by a real-time polymerase chain reaction amplification assay.

RESULTS

The frequency (0.28) of the 105Val polymorphism was identical in COPD patients and the general population. However, the frequency was significantly increased (0.44) in patients with AAT deficiency (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.17 to 3.72 compared to control subjects; and OR, 2.41; 95% CI, 1.27 to 4.59 compared to COPD). FEV(1) percentage of predicted was significantly impaired in AAT-deficient carriers of 105Val. This effect was not observed in COPD patients.

CONCLUSIONS

These findings suggest that the frequency of the GSTP1 105Val polymorphism is increased in patients with AAT deficiency. Globally, GSTP1 genotypes, age, and tobacco smoking explained 41% of total FEV(1) percentage of predicted variability in patients with AAT deficiency. The modulatory role of GSTP1 in lung disease has only been observed in smokers lacking AAT.

Sodium pertechnetate (Na99mTcO4) biodistribution in mice exposed to cigarette smoke

BACKGROUND: The biological effects of cigarette smoke are not fully known. To improve our understanding of the action of various chemical agents, we investigated the biodistribution of sodium pertechnetate (Na99mTcO4) in mice exposed to cigarette smoke. METHODS: Fifteen BALB/c male mice were exposed to the smoke of nine whole commercial cigarettes per day, 3 times/day, for up to 10 days to whole body exposure in a chamber. A control group of 5 BALB/c male mice was sham-smoked. One day later, the exposed and control groups of mice received (7.4 MBq/0.3 ml) of Na99mTcO4 before being killed at 30 min. Bones, brain, heart, intestine, kidney, liver, lungs, muscle, pancreas, spleen, stomach, testis and thyroid were weighed and these organs and blood radioactivity recorded with a gamma counter. The percentage per gram of tissue of injected dose (%ID/g) was determined for each organ. RESULTS: Cigarette smoke significantly decreased (p < 0.05) the %ID/g in red blood cells, bone, kidney, lung, spleen, stomach, testis and thyroid of the exposed mice. CONCLUSION: The toxic effects of cigarette smoke reduced the Na99mTcO4 biodistribution.

The Role of Oxidative Stress in the Pathogenesis??of COPD

Chronic inflammation and oxidative stress are important features in the pathogenesis of COPD. The increased oxidative stress in patients with COPD is the result of an increased burden of inhaled oxidants, as well as increased amounts of reactive oxygen species (ROS) generated by various inflammatory, immune and epithelial cells of the airways. Oxidative stress has important implications on several events of lung physiology and for the pathogenesis of COPD. These include oxidative inactivation of antiproteases and surfactants, mucus hypersecretion, membrane lipid peroxidation, mitochondrial respiration, alveolar epithelial injury, remodeling of extracellular matrix, and apoptosis. An increased level of ROS produced in the airways is reflected by increased markers of oxidative stress in the airspaces, sputum, breath, lungs, and blood in patients with COPD. The biomarkers of oxidative stress such as H2O2, F2-isoprostanes, malondialdehyde and 4-hydroxy-2-nonenal have been successfully measured in breath condensate. ROS and aldehydes play a key role in enhancing the inflammation through the activation of mitogen-activated protein kinases and redox-sensitive transcription factors such as nuclear factor kappa B and activator protein-1. Oxidative stress also alters nuclear histone acetylation and deacetylation leading to increased gene expression of pro-inflammatory mediators in the lung. Oxidative stress may play a role in the poor clinical efficacy of corticosteroids in the treatment of COPD. Since a variety of oxidants, free radicals, and aldehydes are implicated in the pathogenesis of COPD it is likely that a combination of antioxidants may be effective in the treatment of COPD. Antioxidant compounds may also be of therapeutic value in monitoring oxidative biomarkers indicating disease progression. Various approaches to enhance the lung antioxidant screen and the clinical effectiveness of antioxidant compounds in the treatment of COPD are discussed.

Increased glutathione disulfide and nitrosothiols in sputum supernatant of patients with stable COPD

STUDY OBJECTIVES

Increased oxidant burden is involved in the pathogenesis of COPD. Glutathione (GSH) is a major antioxidant scavenging reactive oxygen and nitrogen species. We studied the concentrations of total and reduced GSH, glutathione disulfide (GSSG), and nitrosothiols in sputum supernatant of patients with COPD.

DESIGN

Twenty-five patients with moderate-to-severe COPD (FEV(1) 61 +/- 12% of predicted) and 25 healthy nonsmoking control subjects underwent sputum induction. Sputum total GSH and GSSG were measured spectrophotometrically, and nitrosothiols were quantified by enzyme assay. Exhaled nitric oxide (eNO) was also measured to correlate eNO with nitrosothiols in induced sputum.

MEASUREMENTS AND RESULTS

Compared with healthy subjects, patients with COPD had increased sputum neutrophils (geometric mean, 65%; 95% confidence interval [CI], 57.5 to 71; vs 21%; 95% CI, 13.2 to 31.6; p < 0.001); total GSH (geometric mean, 7.1 micromol/L; 95% CI, 2.95 to 17; vs 5.1 micromol/L; 95% CI, 3.2 to 8.1; p = 0.024); GSSG (geometric mean, 4.1 micromol/L; 95% CI, 1.7 to 10; vs 0.84 micromol/L; 95% CI, 0.35 to 1.99; p = 0.002); and nitrosothiols (geometric mean, 60.4 micromol/L; 95% CI, 40 to 95.5; vs 38 micromol/L; 95% CI, 31.6 to 43.6; p = 0.04). Sputum GSSG was positively correlated with neutrophils (rho = 0.47, p = 0.016) and nitrosothiols (rho = 0.49, p = 0.024) in patients with COPD, whereas there was no correlation of eNO with nitrosothiols (rho = 0.38, p = 0.1).

CONCLUSIONS

Sputum concentrations of GSSG and nitrosothiols are increased in patients with COPD and associated with neutrophilic inflammation. These data underline the role of oxidative stress in the pathogenesis of COPD, and suggest that GSH is important to scavenge both reactive oxygen and nitrogen species.

The effects of antioxidants on exercise-induced lipid peroxidation in patients with COPD

OBJECTIVE

The oxidant-antioxidant balance plays an important role in the pathogenesis of COPD. The aim of the present study was to evaluate the effects of exercise, as an oxidative stress factor on the oxidant-antioxidant balance and to investigate whether short-term antioxidant treatment affects lipid peroxidation products.

METHODOLOGY

Twenty-one stable COPD patients and 10 control subjects were included in the study. Symptom-limited exercise tests were performed by all subjects. Blood was collected before and 1 h after exercise in control subjects and before, 1 and 3 h after exercise in COPD patients, for analysis of malondialdehyde (MDA), reduced glutathione (GSH) and vitamin E (VE) levels. VE and vitamin C treatments were added to the regular bronchodilator therapy in 10 COPD patients for 1 month. After the treatment period, an exercise test was performed and blood was collected again for MDA, GSH and VE levels.

RESULTS

Baseline GSH and VE levels were significantly lower in the COPD group when compared with the control subjects. There was no statistically significant difference in MDA levels between the two groups. In the COPD group, MDA levels 3 h after exercise were significantly higher than at baseline. In contrast there were no significant differences in MDA, VE and GSH levels in the control group after exercise. VE and MDA levels increased significantly after exercise in COPD patients but there was no difference in GSH levels. Baseline exercise time was significantly lower in the COPD group than in the controls. In 10 COPD patients who were given antioxidant therapy, their exercise time increased significantly and there was no increase in MDA and VE levels after the repeated exercise test.

CONCLUSIONS

Antioxidant levels were significantly lower in COPD patients than in control subjects. In these patients, exercise results in more significant oxidative stress and lipid peroxidation than in control subjects and antioxidant therapy may decrease lipid peroxidation following exercise and improve exercise capacity.

Trace elements as a component of oxidative stress in COPD

OBJECTIVE

The purpose of this study was to assess the serum concentrations of those trace elements that act as a component of oxidative stress in COPD patients. Clinically stable COPD outpatients (n = 26) and healthy controls (n = 24) were studied.

METHODOLOGY

Serum concentrations of copper (Cu) and zinc (Zn) were determined using a Varian Spectra AA220 flame atomic absorption spectrophotometer. Serum concentration of iron (Fe) was measured by the ferene assay, using a commercially available kit (IL Test Iron) with the ILAb 900 autoanalyser. The lipid peroxidation product malondialdehyde (MDA) in serum samples was measured spectrophotometrically in terms of TBARS (thiobarbituric acid reactive substances).

RESULTS

The serum MDA concentration in COPD patients was found to be similar to the control group (0.68 +/- 0.15 nmol/mL vs 0.62 +/- 0.13 nmol/mL, respectively; P= 0.163). The serum concentrations of the trace elements in both study groups were in the normal reference range. There was no difference in Fe concentration between COPD patients and the control group (0.81 +/- 0.38 micro g/mL vs 0.92 +/- 0.41 micro g/mL; P= 0.360). Copper concentrations were higher (1.06 +/- 0.26 microg/mL vs 0.92 +/- 0.19 microg/mL; P <0.040); while zinc was lower in the COPD group compared to the controls (0.83 +/- 0.25 microg/mL vs 1.03 +/- 0.23 microg/mL; P= 0.006). Serum Zn concentrations were lower in the severe COPD patients compared to mild-moderate COPD patients (P = 0.038).

CONCLUSION

The results of this study indicate that there are alterations in serum concentrations of trace elements in COPD patients, suggesting that they may play a role in the pathophysiology of this disease by virtue of their role in oxidative stress. We recommend further studies on the role of trace elements in the pathophysiology of COPD, their association with markers of oxidant/antioxidant status and on the clinical significance of their deficiency.

Oxidative stress in expired breath condensate of patients with COPD

OBJECTIVE

To evaluate the levels of hydrogen peroxide (H(2)O(2)) and 8-isoprostane in the expired breath condensate (EBC) of patients with COPD, and to assess the relationship between the above markers of oxidative stress and parameters expressing inflammatory process and disease severity.

SETTING

Inpatient respiratory unit and outpatient clinic in tertiary care hospital.

DESIGN

Cross-sectional study.

PATIENTS

Thirty stable COPD patients (all smokers) with disease severity ranging from mild to severe. Ten subjects who were smokers with stage 0 disease (ie, at risk for COPD; mean [+/- SD] FEV(1), 88 +/- 5% predicted) were studied as a control group.

METHODS

H(2)O(2) and 8-isoprostane levels were measured in EBC, and the values were correlated with variables expressing COPD severity (ie, FEV(1) percent predicted, dyspnea severity score (ie, Medical Research Council scale) and airway inflammation (ie, differential cell counts from induced sputum).

RESULTS

The mean concentration of H(2)O(2) was significantly elevated in COPD patients compared to control subjects (mean, 0.66 micromol/L [95% confidence interval (CI), 0.54 to 0.68 micro mol/L) vs 0.31 micro mol/L [95% CI, 0.26 to 0.35 micromol/L], respectively; p < 0.0001). The difference was primarily due to the elevation of H(2)O(2) in patients with severe and moderate COPD, whose expired breath H(2)O(2) levels were significantly higher than those of patients with mild disease (mean, 0.96 micromol/L [95% CI, 0.79 to 1.13 micromol/L], 0.68 micromol/L [95% CI, 0.55 to 0.81 micromol/L], and 0.33 micromol/L [95% CI, 0.24 to 0.43 micromol/L], respectively, p < 0.0001). The mean concentration of 8-isoprostane was significantly elevated in patients with COPD compared to that of the control group (47 pg/mL [95% CI, 41 to 53 pg/mL] vs 29 pg/mL [95% CI, 25 to 33 pg/mL], respectively; p < 0.0001) but did not differ significantly among the different stages of the disease (p = 0.43). Repeatability and stability data within measurements showed that H(2)O(2) has a better repeatability and stability than 8-isoprostane. Furthermore, we observed significant correlations of H(2)O(2) with FEV(1), neutrophil count, and dyspnea score. Those correlations existed only in patients with moderate and severe disease. No correlations were found between levels of 8-isoprostane and the above parameters.

CONCLUSIONS

We conclude that levels of H(2)O(2) and 8-isoprostane are elevated in the EBC of patients with COPD, but that H(2)O(2) seems to be a more repeatable and a more sensitive index of the inflammatory process and the severity of the disease.

Oxidative Stress, Cell Death, and Other Damage to Alveolar Epithelial Cells Induced by Cigarette Smoke

Cigarette smoking is a major risk factor in the development of various lung diseases, including pulmonary emphysema, pulmonary fibrosis, and lung cancer. The mechanisms of these diseases include alterations in alveolar epithelial cells, which are essential in the maintenance of normal alveolar architecture and function. Following cigarette smoking, alterations in alveolar epithelial cells induce an increase in epithelial permeability, a decrease in surfactant production, the inappropriate production of inflammatory cytokines and growth factors, and an increased risk of lung cancer. However, the most deleterious effect of cigarette smoke on alveolar epithelial cells is cell death, i.e., either apoptosis or necrosis depending on the magnitude of cigarette smoke exposure. Cell death induced by cigarette smoke exposure can largely be accounted for by an enhancement in oxidative stress. In fact, cigarette smoke contains and generates many reactive oxygen species that damage alveolar epithelial cells. Whether apoptosis and/or necrosis in alveolar epithelial cells is enhanced in healthy cigarette smokers is presently unclear. However, recent evidence indicates that the apoptosis of alveolar epithelial cells and alveolar endothelial cells is involved in the pathogenesis of pulmonary emphysema, an important cigarette smoke-induced lung disease characterized by the loss of alveolar structures. This review will discuss oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke.

Oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke

Cigarette smoking is a major risk factor in the development of various lung diseases, including pulmonary emphysema, pulmonary fibrosis, and lung cancer. The mechanisms of these diseases include alterations in alveolar epithelial cells, which are essential in the maintenance of normal alveolar architecture and function. Following cigarette smoking, alterations in alveolar epithelial cells induce an increase in epithelial permeability, a decrease in surfactant production, the inappropriate production of inflammatory cytokines and growth factors, and an increased risk of lung cancer. However, the most deleterious effect of cigarette smoke on alveolar epithelial cells is cell death, i.e., either apoptosis or necrosis depending on the magnitude of cigarette smoke exposure. Cell death induced by cigarette smoke exposure can largely be accounted for by an enhancement in oxidative stress. In fact, cigarette smoke contains and generates many reactive oxygen species that damage alveolar epithelial cells. Whether apoptosis and/or necrosis in alveolar epithelial cells is enhanced in healthy cigarette smokers is presently unclear. However, recent evidence indicates that the apoptosis of alveolar epithelial cells and alveolar endothelial cells is involved in the pathogenesis of pulmonary emphysema, an important cigarette smoke-induced lung disease characterized by the loss of alveolar structures. This review will discuss oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke.

Lung function and mortality in the United States: data from the First National Health and Nutrition Examination Survey follow up study

BACKGROUND

A study was undertaken to define the risk of death among a national cohort of US adults both with and without lung disease.

METHODS

Participants in the first National Health and Nutrition Examination Survey (NHANES I) followed for up to 22 years were studied. Subjects were classified using a modification of the Global Initiative for Chronic Obstructive Lung Disease criteria for chronic obstructive pulmonary disease (COPD) into the following mutually exclusive categories using the forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC ratio, and the presence of respiratory symptoms: severe COPD, moderate COPD, mild COPD, respiratory symptoms only, restrictive lung disease, and no lung disease. Proportional hazard models were developed that controlled for age, race, sex, education, smoking status, pack years of smoking, years since quitting smoking, and body mass index.

RESULTS

A total of 1301 deaths occurred in the 5542 adults in the cohort. In the adjusted proportional hazards model the presence of severe or moderate COPD was associated with a higher risk of death (hazard ratios (HR) 2.7 and 1.6, 95% confidence intervals (CI) 2.1 to 3.5 and 1.4 to 2.0), as was restrictive lung disease (HR 1.7, 95% CI 1.4 to 2.0).

CONCLUSIONS

The presence of both obstructive and restrictive lung disease is a significant predictor of earlier death in long term follow up.

Influence of smoking on markers of oxidative stress and serum mineral concentrations in teenage girls in Korea

OBJECTIVE

The purpose of this study was to examine the effect of cigarette smoking on serum oxidative damage, antioxidant status, and mineral concentrations in teenage girls.

METHODS

Subjects were randomly chosen from female senior high school students (15-17 y) in a rural community in Korea. Smoker (n = 19) was defined as a person who had smoked 10 or more cigarettes/d continually for at least 1 y while non-smoker (n = 19) was a person who had no previous smoking experience. All individuals in smoker group had serum cotinine concentrations greater than 110 ng/mL, and those in non-smoker group had concentrations of less than 30 ng/mL. Serum oxidative defense enzyme activities, serum antioxidant nutrient concentrations, anthropometric data, and dietary nutrient intakes were evaluated.

RESULTS

Serum selenium glutathione peroxidase, glutathione reductase, and extracellular superoxide dismutase activities were lower in smokers than in non-smokers. Serum ascorbic acid and folate concentrations were lower in smokers than in non-smokers, whereas serum thiobarbituric acid-reactive substances (TBARS) were higher. Serum copper, iron, and magnesium concentrations were similar in the two groups. Serum zinc concentrations were higher in smokers.

CONCLUSIONS

Teenagers with a short smoking history can have evidence of oxidative stress (high serum TBARS and low serum ascorbic acid and folate concentrations) and an impaired oxidant defense system. However, in contrast to common findings in adult smokers, blood pressure was lower in teenage smokers, and hypozincemia and hypercupremia were not observed. Alterations observed in mineral metabolism in adult smokers are probably secondary to chronic diseases associated with long-term smoking.

Characteristics of adults dying with COPD

STUDY OBJECTIVE

To describe factors associated with COPD deaths in the United States.

DESIGN

Cross-sectional survey.

PARTICIPANTS

A total of 12,803 decedents in the National Mortality Followback Survey, a nationally representative sample of US deaths in 1993.

METHODS

We compared the characteristics of adults > or = 35 years of age who died with COPD (bronchitis, emphysema, chronic airway obstruction) with those dying without COPD listed on their death certificates.

RESULTS

Of the estimated 225,400 adults who died with COPD in 1993, 16.7% had never smoked. People dying with COPD were more likely than those dying without COPD to be current smokers (odds ratio [OR], 6.5; 95% confidence interval [CI], 4.3 to 9.9) or former smokers (OR, 3.7; 95% CI, 2.5 to 5.3), have a history of asthma (OR, 5.0; 95% CI, 3.2 to 7.8), be underweight (OR, 4.5; 95% CI, 2.8 to 7.2), and be of the white race (OR, 3.1; 95% CI, 2.4 to 4.0), after controlling for age group and sex.

CONCLUSIONS

A significant proportion of COPD-related deaths occurs in never-smokers. Factors such as a history of asthma and being underweight are associated with COPD mortality and may provide additional opportunities for intervention.

Detection of polymorphisms at exons 3 (Tyr113-->His) and 4 (His139-->Arg) of the microsomal epoxide hydrolase gene using fluorescence PCR method combined with melting curves analysis

An association between exon 3 polymorphisms of the gene encoding microsomal epoxide hydrolase (mEH) and susceptibility to the development of chronic obstructive pulmonary disease (COPD) has been described. We have developed two methods for detecting polymorphisms at exons 3 (Tyr113-->His) and 4 (His139-->Arg) of the mEH gene based on different melting temperatures (T(m)) of fluorescent-labeled oligonucleotide hybridization probes using single-step assays that combine fluorescence PCR and melting curve analysis (LightCycler methodology). DNA was extracted from blood in 79 COPD patients and 146 healthy controls. Results were compared with those obtained by restriction fragment length polymorphism (RFLP) analysis to detect Tyr113His variants and a single-strand conformation polymorphism (SSCP) assay for His139Arg detection. The T(m) of the exon 3 polymorphisms were 61.3 degrees C for Tyr113 (wild type) and 67.5 degrees C for His113 (mutant). The T(m) values of the exon 4 polymorphisms were 67.5 degrees C for His139 (wild type) and 59.2 degrees C for Arg139 (mutant). The within- and between-run melting peaks for the same allele differed by less than 0.5 degrees C for both the exon 3 and the exon 4 polymorphisms. Thus, melting analysis allowed easy and unambiguous assignment of genotyping by means of the respective melting curves. The proportion of individuals who were homozygous mutant for exon 3 was significantly higher in the COPD group than in the control group (p=0.004). LightCycler fluorescence genotyping of exon 4 polymorphisms correlated perfectly with SSCP results. RFLP assay classified 2 patients as homozygous mutant while LightCycler analysis genotyped them as heterozygous. DNA analysis by PCR and sequencing confirmed the LightCycler result. These high-speed (about 40 min for 32 samples), highly sensitive, and specific small-volume assays with low labor requirements hold great promise as tools for rapid detection of COPD susceptibility.

Lipofuscin accumulation in the vastus lateralis muscle in patients with chronic obstructive pulmonary disease

Exercise-induced oxidative stress has been reported in patients with chronic obstructive pulmonary disease (COPD) and may play a role in muscle fatigue. It is speculated that oxidative stress during exercise originates from the contracting muscles but this has not been documented. The accumulation of lipofuscin, a marker of cellular oxidative damage, was evaluated in the vastus lateralis muscle in 17 patients with COPD and 10 healthy subjects of similar age. Each subject performed a stepwise exercise test up to maximal capacity during which oxygen uptake (VO(2)) was measured. Resting and peak exercise blood gases were also obtained. Two indices of lipofuscin accumulation were used: lipofuscin inclusions/fiber ratio (LI/F) and lipofuscin inclusions/fiber cross-sectional area ratio (LI/CSA). These ratios were also determined for each specific fiber-type. LI/F (P < 0.01) and LI/CSA (P < 0.01) were greater in COPD compared to healthy subjects. LI/F and LI/CSA for all fiber types were also greater in COPD (P < 0.001). In both groups, LI/F (P < 0.001) and LI/CSA (P < 0.01) were higher in type I than in type II fibers. LI/F and LI/CSA did not correlate significantly with resting PaO(2) and SaO(2), peak VO(2), and DeltaPaO(2) and DeltaSaO(2) during exercise (P > 0.05). Increased lipofuscin accumulation, a marker of oxidative damage, was found in the vastus lateralis muscle in patients with COPD compared to healthy subjects. Oxidative damage of muscle tissue may thus be involved in skeletal muscle dysfunction and wasting in COPD.

Smoking and airway inflammation in patients with mild asthma

STUDY OBJECTIVES

Cigarette smoking is common in asthmatic patients, and we investigated the impact of cigarette smoking on airway inflammation in asthma.

DESIGN

Single-center observational study of airway inflammation in asthmatic and healthy smokers and nonsmokers.

SETTING

Asthma research unit in a university hospital.

PATIENTS OR PARTICIPANTS

Sixty-seven asthmatic and 30 nonasthmatic subjects classified as smokers or nonsmokers. Asthmatics had chronic, stable asthma and were not receiving inhaled or oral steroids at the time of the study.

INTERVENTIONS

We examined induced-sputum cell counts and levels of interleukin (IL)-8 and eosinophilic cationic protein (ECP). Bronchial hyperreactivity was assessed using methacholine challenge.

MEASUREMENTS AND RESULTS

Asthmatic smokers had higher total sputum cell counts than nonsmoking asthmatics and both smoking and nonsmoking healthy subjects. Smoking was associated with sputum neutrophilia in both asthmatics and nonasthmatics (median, 47% and 41%, respectively) compared with nonsmokers (median, 23% and 22%, respectively), and sputum IL-8 was increased in smokers compared with nonsmokers, both in subjects with asthma (median, 945 pg/mL vs 660 pg/mL, respectively) and in healthy subjects (median, 1,310 pg/mL vs 561 pg/mL, respectively). Sputum eosinophils and ECP levels were higher in both nonsmoking and smoking asthmatics than in healthy nonsmokers. In smoking asthmatics, lung function (FEV(1) percent predicted) was negatively related to both sputum IL-8 (r = - 0.52) and sputum neutrophil proportion (r = - 0.38), and sputum IL-8 correlated positively with smoking pack-years (r = 0.57) and percent neutrophil count (r = 0.51).

CONCLUSIONS

In addition to the eosinophilic airway inflammation observed in patients with asthma, smoking induces neutrophilic airway inflammation; a relationship is apparent between smoking history, airway inflammation, and lung function in smoking asthmatics.

Ambient particle inhalation and the cardiovascular system: potential mechanisms

Well-documented air pollution episodes throughout recent history have led to deaths among individuals with cardiovascular and respiratory disease. Although the components of air pollution that cause the adverse health effects in these individuals are unknown, a small proportion by mass but a large proportion by number of the ambient air particles are ultrafine, i.e., less than 100 nm in diameter. This ultrafine component of particulate matter with a mass median aerodynamic diameter less than 10 microm (PM(10) may mediate some of the adverse health effects reported in epidemiologic studies and for which there is toxicologic evidence to support this contention. The exact mechanism by which ultrafine particles have adverse effects is unknown, but these particles have recently been shown to enhance calcium influx on contact with macrophages. Oxidative stress is also to be anticipated at the huge particle surface; this can be augmented by oxidants generated by recruited inflammatory leukocytes. Atheromatous plaques form in the coronary arteries and are major causes of morbidity and death associated epidemiologically with particulate air pollution. In populations exposed to air pollution episodes, blood viscosity, fibrinogen, and C-reactive protein (CRP) were higher. More recently, increases in heart rate in response to rising air pollution have been described and are most marked in individuals who have high blood viscosity. In our study of elderly individuals, there were significant rises in CRP, an index of inflammation. In this present review, we consider the likely interactions between the ultrafine particles the acute phase response and cardiovascular disease.

Ambient particle inhalation and the cardiovascular system: potential mechanisms

Well-documented air pollution episodes throughout recent history have led to deaths among individuals with cardiovascular and respiratory disease. Although the components of air pollution that cause the adverse health effects in these individuals are unknown, a small proportion by mass but a large proportion by number of the ambient air particles are ultrafine, i.e., less than 100 nm in diameter. This ultrafine component of particulate matter with a mass median aerodynamic diameter less than 10 microm (PM(10) may mediate some of the adverse health effects reported in epidemiologic studies and for which there is toxicologic evidence to support this contention. The exact mechanism by which ultrafine particles have adverse effects is unknown, but these particles have recently been shown to enhance calcium influx on contact with macrophages. Oxidative stress is also to be anticipated at the huge particle surface; this can be augmented by oxidants generated by recruited inflammatory leukocytes. Atheromatous plaques form in the coronary arteries and are major causes of morbidity and death associated epidemiologically with particulate air pollution. In populations exposed to air pollution episodes, blood viscosity, fibrinogen, and C-reactive protein (CRP) were higher. More recently, increases in heart rate in response to rising air pollution have been described and are most marked in individuals who have high blood viscosity. In our study of elderly individuals, there were significant rises in CRP, an index of inflammation. In this present review, we consider the likely interactions between the ultrafine particles the acute phase response and cardiovascular disease.