Cigarette smoke radicals and the role of free radicals in chemical carcinogenicity

A protocol for detecting and scavenging gas-phase free radicals in mainstream cigarette smoke

Cigarette smoking is associated with human cancers. It has been reported that most of the lung cancer deaths are caused by cigarette smoking (5,6,7,12). Although tobacco tars and related products in the particle phase of cigarette smoke are major causes of carcinogenic and mutagenic related diseases, cigarette smoke contains significant amounts of free radicals that are also considered as an important group of carcinogens(9,10). Free radicals attack cell constituents by damaging protein structure, lipids and DNA sequences and increase the risks of developing various types of cancers. Inhaled radicals produce adducts that contribute to many of the negative health effects of tobacco smoke in the lung(3). Studies have been conducted to reduce free radicals in cigarette smoke to decrease risks of the smoking-induced damage. It has been reported that haemoglobin and heme-containing compounds could partially scavenge nitric oxide, reactive oxidants and carcinogenic volatile nitrosocompounds of cigarette smoke(4). A 'bio-filter' consisted of haemoglobin and activated carbon was used to scavenge the free radicals and to remove up to 90% of the free radicals from cigarette smoke(14). However, due to the cost-ineffectiveness, it has not been successfully commercialized. Another study showed good scavenging efficiency of shikonin, a component of Chinese herbal medicine(8). In the present study, we report a protocol for introducing common natural antioxidant extracts into the cigarette filter for scavenging gas phase free radicals in cigarette smoke and measurement of the scavenge effect on gas phase free radicals in mainstream cigarette smoke (MCS) using spin-trapping Electron Spin Resonance (ESR) Spectroscopy(1,2,14). We showed high scavenging capacity of lycopene and grape seed extract which could point to their future application in cigarette filters. An important advantage of these prospective scavengers is that they can be obtained in large quantities from byproducts of tomato or wine industry respectively(11,13).

Could zinc prevent reproductive alterations caused by cigarette smoke in male rats?

The aim of the present study was to evaluate the effects of zinc on fertility through semen parameters, testosterone level and oxidative DNA damage to spermatozoa of rats exposed to cigarette smoke. Male Wistar rats (60 days old) were divided into four groups (n = 10 per group): control, cigarette-smoking (20 cigarettes per day), zinc (zinc chloride 20 mg kg–1 day–1) and zinc plus cigarette-smoking (zinc chloride 20 mg kg–1 day–1; 20 cigarettes per day). The treatment was applied for nine weeks and the following parameters were analysed: bodyweight, wet weights of the reproductive organs and the adrenal gland, plasma testosterone concentration, testicular function (seminal analysis and daily sperm production) and sperm DNA oxidative damage. The exposure to cigarette smoke decreased testosterone concentration, the percentage of normal morphology and the motility of spermatozoa. In addition, this exposure increased sperm DNA oxidative damage. Zinc treatment protected against the toxic damage that smoking caused to spermatozoa. This study showed a correlation between smoking and possible male infertility and subfertility, and also that the majority of smoking-induced changes in spermatozoa were prevented by zinc treatment. In conclusion, zinc, an antioxidant and stimulant of cell division, can be indicated as a promising treatment in men with infertility caused by the toxic components of cigarette smoke.

Effect of n-3 fatty acids on patients with advanced lung cancer: a double-blind, placebo-controlled study

PUFA from fish oil appear to have anti-inflammatory and anti-oxidative effects and improve nutritional status in cancer patients. With this as background, the aim of the present study was to investigate the effect of EPA plus DHA on inflammatory condition, and oxidative and nutritional status in patients with lung cancer. In our multicentre, randomised, double-blind trial, thirty-three patients with a diagnosis of advanced inoperable non-small-cell lung cancer and undergoing chemotherapy were divided into two groups, receiving four capsules/d containing 510 mg of EPA and 340 mg of DHA, or 850 mg of placebo, for 66 d. At the start of chemotherapy (T0), after 8 d (T1), 22 d (T2) and 66 d (T3), biochemical (inflammatory and oxidative status parameters) and anthropometric parameters were measured in both groups. A significant increase of body weight in the n-3 group at T3v. T0 was observed. Concerning inflammation, C-reactive protein and IL-6 levels differed significantly between the n-3 and placebo groups at T3, and progressively decreased during chemotherapy in the n-3 group, evidencing n-3 PUFA anti-inflammatory action. Concerning oxidative status, plasma reactive oxygen species levels increased in the placebo group v. the n-3 group at the later treatment times. Hydroxynonenal levels increased in the placebo group during the study, while they stabilised in the n-3 group. Our data confirm that the continual assumption of EPA plus DHA determined an anti-inflammatory and anti-oxidative action which could be considered a preliminary goal in anti-cachectic therapy.

Morpho-functional modifications of human neutrophils induced by aqueous cigarette smoke extract: comparison with chemiluminescence activity

Cigarette smoking plays an important role as a cause of morbidity and mortality in humans, involving respiratory, cardiovascular, digestive and reproductive systems. Tobacco smoke contains a large number of molecules, some of which are proven carcinogens. Although not fully understood, polymorphonuclear leukocytes seem to play a crucial role in the mechanisms by which tobacco smoke compounds are implicated in smoke-related diseases. In this paper the effects of an aqueous cigarette smoke extract on the expression of adhesion molecules of polymorphonuclear leukocytes together with the changes in the cell morphology have been related to the chemiluminescence activity. The results obtained show that polymorphonuclear leukocytes treated with aqueous cigarette smoke extract are significantly impaired, as suggested by the changes of chemiluminescence activity, of membrane receptors (CD18, CD62), myeloperoxidase expression and of cell morphology. Altogether the present data indicate that treated polymorphonuclear leukocytes are ineffectively activated and therefore unable to phagocytize zymosan particles.

Increase of urinary concentrations of 8-hydroxy-2'-deoxyguanosine in diesel exhaust emission inspector exposed to polycyclic aromatic hydrocarbons

PURPOSE

The objectives of this study were to explore the factors influencing urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in diesel engine exhaust emission inspectors (inspectors), the association between polycyclic aromatic hydrocarbons (PAHs) exposure and fine particulate matter (PM(2.5)) levels in diesel exhaust particles (DEPs), and the PAHs exposure levels in diesel vehicle emission inspection stations (inspection stations).

METHODS

Twenty-eight inspectors and a control group of thirty-eight individuals matched by age and gender were recruited for this study. Fifteen ambient air samples and eighty-four personal air samples were monitored during 3-day work periods using a repeated-measures study design in each inspection station. Airborne samples were analyzed with a fluorescence detector and by high-performance liquid chromatography. Urinary 8-OHdG was measured in 168 pre- and post-work urine samples from inspectors, and in 38 urine samples from controls.

RESULTS

The concentrations of PAHs in DEP(2.5) (PM(2.5) in DEPs) were significantly and positively related to urinary log(10) 8-OHdG levels after adjusting for smoking status and BMI. Statistically, there was a significant correlation between air log(10) PAHs and air log(10) PM(2.5) concentrations in inspectors. Fifteen PAHs compounds within DEP(2.5) revealed the concentrations ranged from 5.18 to 22.93 ng/m(3) in ambient air monitoring and 1.03 to 12.60 ng/m(3) in personal air monitoring.

CONCLUSIONS

This study is the first to indicate an association between occupational PAHs exposure from DEP(2.5) at an inspection station and an increased excretion of urinary 8-OHdG in inspectors. In addition, this study also found smoking is not a confounder in inspectors exposed to PAHs in DEP(2.5).

Subacute effect of cigarette smoke exposure in rats: protection by pot marigold (Calendula officinalis L.) extract

This study was carried out to determine the preventive effect of Calendula officinalis L. (pot marigold) on rats exposed to cigarette smoke (CS). Rats were divided into three groups as control, CS and CS + pot marigold (PM). The rats in the CS and CS + PM groups were subjected to CS for 1 h twice a day for 23 days. PM (100 mg/kg body weight) was given to rats in the CS + PM group by gavage, 1 h before each administration period. While malondialdehyde, protein carbonyl contents and reduced glutathione level of the CS group increased, their levels diminished by PM administration. In addition, glutathione peroxidase (GPx), superoxide dismutase activities and β-carotene, vitamins A and C levels decreased in the CS group compared to control, however activities of these enzymes and concentration of vitamins were elevated by PM supplementation. This investigation showed that administration of PM supplied relative protection against subacute CS-induced cell injury.

Protective effects of plasma alpha-tocopherols on the risk of inorganic arsenic-related urothelial carcinoma

Arsenic plays an important role in producing oxidative stress in cultured cells. To investigate the interaction between high oxidative stress and low arsenic methylation capacity on arsenic carcinogenesis, a case-control study was conducted to evaluate the relationship among the indices of oxidative stress, such as urinary 8-hydroxydeoxyquanine (8-OHdG), as well as plasma micronutrients and urinary arsenic profiles on urothelial carcinoma (UC) risk. Urinary 8-OHdG was measured using high-sensitivity enzyme-linked immunosorbent assay kits. The urinary arsenic species were analyzed using high-performance liquid chromatography and hydride generator-atomic absorption spectrometry. Plasma micronutrient levels were analyzed using reversed-phase high-performance liquid chromatography. The present study showed a significant protective effect of plasma alpha-tocopherol on UC risk. Plasma alpha-tocopherol levels were significantly inversely related to urinary total arsenic concentrations and inorganic arsenic percentage (InAs%), and significantly positively related to dimethylarsinic acid percentage (DMA%). There were no correlations between plasma micronutrients and urinary 8-OHdG. Study participants with lower alpha-tocopherol and higher urinary total arsenic, higher InAs%, higher MMA%, and lower DMA% had a higher UC risk than those with higher alpha-tocopherol and lower urinary total arsenic, lower InAs%, lower MMA%, and higher DMA%. These results suggest that plasma alpha-tocopherol might modify the risk of inorganic arsenic-related UC.

Increased erythrocyte antioxidant status protects against smoking induced hemolysis in moderate smokers

Cigarette smoking is common in societies worldwide and has been identified as injurious to human health. Human red blood cells are important targets for electrophilic and oxidant foreign compounds. In the present study, the possible role of antioxidant status on smoking-induced erythrocyte hemolysis of smokers was studied. Erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, reduced glutathione (GSH) level, erythrocyte membrane lipid peroxidation, total cholesterol and phospholipids were determined. Further, nitrite/nitrate levels (NO2/NO3) in both plasma and erythrocyte lysate were measured. Results showed increased plasma and erythrocyte membrane lipid peroxidation and nitrite/nitrate levels in smokers. The activities of SOD, CAT and GPx were also increased with reduced glutathione (GSH) level in smokers. No significant change was observed in smokers red cell hemolysis and cholesterol/phospholipid (C/P) ratio compared to controls. Erythrocyte membrane lipid peroxidation was positively correlated with SOD ( r = 0.482, p < 0.01) and GPx ( r = 0.368, p < 0.018) in smokers. Increased levels of nitrite/nitrate and antioxidant status of erythrocytes might be playing a crucial role in protecting red cell from free radical damage induced by cigarette smoke.

Levels of Exhaled Breath Condensate pH and Fractional Exhaled Nitric Oxide in Retired Coal Miners

Inhaled inorganic dusts, such as coal, can cause inflammation and fibrosis in the lungs, known as pneumoconiosis. Diagnosis of pneumoconiosis depends on morphological changes by radiological findings and functional change by pulmonary function test (PFT) . Unfortunately, current diagnostic findings are limited only to lung fibrosis, which is usually irreversibly progressive. Therefore, it is important that research on potential and prospective biomarkers for pneumoconiosis should be conducted prior to initiation of irreversible radiological or functional changes in the lungs. Analytical techniques using exhaled breath condensate (EBC) or exhaled gas are non-invasive methods for detection of various respiratory diseases. The objective of this study is to investigate the relationship between inflammatory biomarkers, such as EBC pH or fractional exhaled nitric oxide (FENO) , and pneumoconiosis among 120 retired coal miners (41 controls and 79 pneumoconiosis patients) . Levels of EBC pH and FENO did not show a statistically significant difference between the pneumoconiosis patient group and pneumoconiosis patients with small opacity classified by International Labor Organization (ILO) classification. The mean concentration of FENO in the low percentage FEV1 (< 80%) was lower than that in the high percentage (80% ≤) (p = 0.023) . The mean concentration of FENO in current smokers was lower than that in non smokers (never or past smokers) (p = 0.027) . Although there was no statistical significance, the levels of FENO in smokers tended to decrease, compared with non smokers, regardless of pneumoconiosis. In conclusion, there was no significant relationship between the level of EBC pH or FENO and radiological findings or PFT. The effects between exhaled biomarkers and pneumoconiosis progression, such as decreasing PFT and exacerbation of radiological findings, should be monitored.

Part I. Development of a model system for studying nitric oxide in tumors: high nitric oxide-adapted head and neck squamous cell carcinoma cell lines

The free radical nitric oxide (NO) is over-expressed in many tumors, including head and neck squamous cell carcinomas (HNSCC); however, the role NO plays in tumor pathophysiology is still not well understood. We, herein, report the development of an in vitro model system which can be used to probe the role of NO in the carcinogenesis of HNSCC. Five HNSCC cell lines were adapted to a high NO (HNO) environment by gradually introducing increasing concentrations of DETA-NONOate, a nitrogen-based NO donor, to cell media. The adaptation process was carried out until a sufficiently high enough donor concentration was reached which enabled the HNO cells to survive and grow, but which was lethal to the original, unadapted ("parent") cells. The adapted HNO cells exhibited analogous morphology to the parent cells, but grew better than their corresponding parent cells in normal media, on soft agar, and in the presence of hydrogen peroxide, an oxygen-based free radical donor. These results indicate that the HNO cell lines are unique and possess biologically different properties than the parent cell lines from which they originated. The HNO/parent cell lines developed herein may be used as a model system to better understand the role NO plays in HNSCC carcinogenesis.

WITHDRAWN: Attenuation of cardiac oxidative stress by (-)-epigallocatechin-gallate (EGCG) in CS exposed rats

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Cigarette smoke-induced biochemical perturbations in human erythrocytes and attenuation by epigallocatechin-3-gallate--tea catechin

The protective effect of epigallocatechin-3-gallate (EGCG) against cigarette smoke (CS) induced alterations in human erythrocyte was studied using an in vitro model. Hemolysis, carboxyhemoglobin, osmotic fragility, hemin, lipid peroxidation (LPO), protein thiol, protein carbonyl, glutathione, antioxidant enzymes, membrane bound ATPases and erythrocyte ghost protein were assessed to investigate the effect of EGCG. Erythrocytes were incubated with CS and/or 10 μM EGCG under physiological conditions of temperature and pH for 2 h. CS significantly increased the percentage of hemolysis, carboxyhemoglobin, hemin, LPO and osmotic fragility in human erythrocytes whereas EGCG pretreatment significantly reduced all the above parameters. The levels of protein carbonyls significantly increased whereas the level of protein thiol decreased significantly in erythrocytes incubated with CS. EGCG pretreatment significantly decreased the levels of carbonyls and increased the level of protein thiol. The level of glutathione, antioxidant enzyme and membrane bound ATPases were decreased significantly in erythrocytes incubated with CS. However, EGCG pretreatment significantly increased the activities of GSH, antioxidant enzymes and membrane bound ATPases. CS incubated erythrocytes showed a progressive loss of the cytoskeleton proteins and formation of low molecular weight bands and protein aggregates. EGCG pretreatment of CS incubated erythrocytes showed a near normal protein profile compared to that of control erythrocytes. The present study divulges that EGCG can reduce the abnormalities of cigarette smoking by ameliorating the oxidative stress. This finding raises the possibility that EGCG may provide protection from CS induced toxicity.

Tabagismo em idosos

O tabagismo representa um importante acelerador do processo de envelhecimento, comprometendo não apenas a expectativa, mas a qualidade de vida também. Fumantes com idade superior a 50 anos apresentam maior dependência da nicotina, fumam há mais tempo e um maior número de cigarros, tendo mais problemas de saúde relacionados ao tabagismo, e dificuldade maior em parar de fumar. As principais causas de morte por tabagismo são as doenças cardiovasculares, a doença pulmonar obstrutiva crônica e o câncer de pulmão. Atualmente, há uma série de estratégias farmacológicas e não-farmacológicas para o auxílio do abandono do tabagismo, que também podem ser uma alternativa para os idosos. O objetivo desta revisão é relatar dados do tabagismo no Brasil e no mundo, as patologias envolvidas e os efeitos tóxicos dos componentes do cigarro, bem como sugerir estratégias de tratamento, principalmente para os idosos. A revisão da literatura foi feita nas bases: Pubmed, Scielo, Portal Capes, Ministério da Saúde, Instituto Nacional do Câncer, IBGE e Organização Mundial da Saúde. Concluiu-se, através da literatura consultada, que o tabagismo representa uma fonte de risco e a causa principal de inúmeras doenças. Porém, o desejo de parar de fumar é maior entre aqueles que reconhecem ser esse hábito prejudicial à saúde. Apesar de os benefícios, com a interrupção do hábito de fumar, serem maiores entre os mais jovens, o abandono do tabagismo, em qualquer idade, reduz o risco de morte e melhora a condição geral de saúde.

Flavonoids of Enhydra Fluctuans Exhibit Anticancer Activity against Ehrlich's Ascites Carcinoma in Mice

Flavonoids obtained from Enhydra fluctuans (FEF) were screened for anticancer activity against Ehrlich's ascites carcinoma (EAC) bearing Swiss albino mice. The anticancer activity was assessed by measuring the tumor growth response, percentage increase of life span, hematological parameters, lipid peroxidation, and antioxidant enzyme activity, like GSH and CAT. Two flavonoids, baicalein 7- O-glucoside and baicalein 7- O-diglucoside, were isolated from the ethyl acetate fraction. Treatment with FEF caused a significant decrease in the tumor cell volume and increase of life span. All the hematological parameters, malonaldehyde content and antioxidant enzyme activity were restored towards the normal level. FEF was found to be cytotoxic in the in-vitro model.

Cigarette smoke promotes dendritic cell accumulation in COPD; a Lung Tissue Research Consortium study

BACKGROUND

Abnormal immune responses are believed to be highly relevant in the pathogenesis of chronic obstructive pulmonary disease (COPD). Dendritic cells provide a critical checkpoint for immunity by their capacity to both induce and suppress immunity. Although evident that cigarette smoke, the primary cause of COPD, significantly influences dendritic cell functions, little is known about the roles of dendritic cells in the pathogenesis of COPD.

METHODS

The extent of dendritic cell infiltration in COPD tissue specimens was determined using immunohistochemical localization of CD83+ cells (marker of matured myeloid dendritic cells), and CD1a+ cells (Langerhans cells). The extent of tissue infiltration with Langerhans cells was also determined by the relative expression of the CD207 gene in COPD versus control tissues. To determine mechanisms by which dendritic cells accumulate in COPD, complimentary studies were conducted using monocyte-derived human dendritic cells exposed to cigarette smoke extract (CSE), and dendritic cells extracted from mice chronically exposed to cigarette smoke.

RESULTS

In human COPD lung tissue, we detected a significant increase in the total number of CD83+ cells, and significantly higher amounts of CD207 mRNA when compared with control tissue. Human monocyte-derived dendritic cells exposed to CSE (0.1-2%) exhibited enhanced survival in vitro when compared with control dendritic cells. Murine dendritic cells extracted from mice exposed to cigarette smoke for 4 weeks, also demonstrated enhanced survival compared to dendritic cells extracted from control mice. Acute exposure of human dendritic cells to CSE induced the cellular pro-survival proteins heme-oxygenase-1 (HO-1), and B cell lymphoma leukemia-x(L) (Bcl-xL), predominantly through oxidative stress. Although activated human dendritic cells conditioned with CSE expressed diminished migratory CCR7 expression, their migration towards the CCR7 ligand CCL21 was not impaired.

CONCLUSIONS

These data indicate that COPD is associated with increased numbers of cells bearing markers associated with Langerhans cells and mature dendritic cells, and that cigarette smoke promotes survival signals and augments survival of dendritic cells. Although CSE suppressed dendritic cell CCR7 expression, migration towards a CCR7 ligand was not diminished, suggesting that reduced CCR7-dependent migration is unlikely to be an important mechanism for dendritic cell retention in the lungs of smokers with COPD.

Oxidative stress targets in pulmonary emphysema: focus on the Nrf2 pathway

IMPORTANCE OF THE FIELD

Oxidative stress has been implicated in the pathogenesis of pulmonary emphysema. Nuclear factor erythroid-2-related factor 2 (Nrf2) a major antioxidant transcription factor could play a protective role in pulmonary emphysema.

AREAS COVERED IN THIS REVIEW

Nrf2 is ubiquitously expressed throughout the lung, but is predominantly found in epithelium and alveolar macrophages. Evidence suggests that Nrf2 and several Nrf2 downstream genes have an essential protective role in the lung against oxidative stress from environmental pollutants and toxicants such as cigarette smoke, a major causative factor for the development and progression of pulmonary emphysema. Application of Nrf2-deficient mice identified an extensive range of protective roles for Nrf2 against the pathogenesis of pulmonary emphysema. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies.

WHAT THE READER WILL GAIN

In this review, we discuss recent findings on the association of oxidative stress with pulmonary emphysema. We also address the mechanisms of Nrf2 lung protection against oxidative stress based on emerging evidence from experimental oxidative disease models and human studie.

TAKE HOME MESSAGE

The current literature suggests that among oxidative stress targets, Nrf2 is a valuable therapeutic target in pulmonary emphysema.

Oxidative stress in non-small cell lung cancer: role of nicotinamide adenine dinucleotide phosphate oxidase and glutathione

BACKGROUND

Cigarette smoke is strongly associated with NSCLC, but the carcinogenesis of NSCLC is poorly understood.

METHODS

To discover the role of oxidative stress and anti-oxidative defense in NSCLC, we measured NADPH oxidase (NOX) activity, myeloperoxidase activity, 8-OHdG, and glutathione content from lung specimens. These came from 32 patients: 22 NSCLC patients and ten controls without cancer.

RESULTS

In NSCLC patients, NOX activity was significantly higher both in the malignant (p = 0.001) and non-malignant (p = 0.044) samples from NSCLC patients, than in the control specimens. Myeloperoxidase activity was lower (p = 0.001) and glutathione content (p = 0.009) higher in malignant tissue. No significant difference was observable in 8-OHdG content between patient groups.

CONCLUSIONS

Increase in NOX activity in the malignant tissues was independent of smoking history and myeloperoxidase activity, suggesting its independent role in NSCLC pathogenesis.

Effect of dietary selenium and cigarette smoke on pulmonary cell proliferation in mice

The objective of this study was to determine if dietary selenium could inhibit pulmonary cell proliferation in control and cigarette smoke-exposed female A/J mice. Selenium in the form of sodium selenite was supplemented to purified diets similar to the AIN-93M diet to yield 0.15, 0.5, or 2.0 mg selenium/kg diet. After 3 weeks, mice in each dietary group were divided into two subgroups; one used as control, whereas the other was exposed to cigarette smoke for five consecutive days. Mice from both groups were euthanized 3 days later. Mice were administered bromodeoxyuridine in the drinking water starting 5 days before the initiation of the smoke exposure and continuing until they were euthanized. After euthanasia, the left lung lobe was processed for histology and cell proliferation analysis. Cigarette smoke increased cell proliferation in the terminal bronchioles and large airways, but not in alveoli. High-selenium diets inhibited cell proliferation in the alveoli, terminal bronchioles and large airways areas in both control and smoke-exposed mice. Increasing the dietary selenium level led to increased selenium levels in the blood and lung, and increased glutathione peroxidase (GPx) activity in the lung. Cytochrome P-450 1A1 protein levels in the lung were increased by cigarette smoke but were not affected by dietary selenium. It is concluded that dietary selenium inhibits pulmonary cell proliferation in both control and cigarette smoke-exposed mice, indicating that selenium is inhibiting cell proliferation independently of smoke exposure, and that this inhibition may be related to selenium concentration and GPx activity in the lung.

Fluorescent detection of lipid peroxidation derived protein adducts upon in-vitro cigarette smoke exposure

Oxidative stress in biological systems can result in radical-induced lipid peroxidation (LPO), which can lead to the production of secondary reactive by-products such as 4-hydroxy-2-nonenal (HNE), malondialdehyde (MDA), acrolein, and acetaldehyde. These deleterious compounds are known to react with and concomitantly modify nucleophilic amino acid residues on proteins. Oxidative stress induced by cigarette smoke (CS) has been put forth as a major mechanism for tobacco-induced pathologies. At present, there are few reliable biomarkers for measuring the extent of oxidatively-induced damage resulting from CS exposure in vivo. This study has utilized a previously reported CS exposure system to expose cultured cells in-vitro to whole CS and determine the extent of LPO resulting from CS exposure by quantifying the increase in HNE within the exposure media versus controls via gas chromatography mass spectrometry. Additionally, we obtained protein enriched cell lysate post-CS exposures and measured the fluorescent signal obtained via direct injection fluorescent analysis at 375 nm ex./415 nm em. This study determined that the fluorescent signal intensity was directly proportional to the quantity increase of HNE in CS exposed media. It further tested this correlation by performing HNE titration addition experiments to cultured cells and Western blot analysis on proteins obtained from cell lysates. Finally, the fluorescent signal increase from authentic BSA solutions incubated with increasing concentrations of HNE was measured. It is proposed that the fluorescent signal observed from the protein lysate of CS exposed cultured cells corresponds to the extent of biological damage resulting from secondary reactive by-products formed from LPO induced via CS exposure and represented by HNE. The fluorescent signals increased in intensity upon increasing CS dose up to 20 min and remained elevated over 24 h after cessation of CS exposure.

Coordinate control of expression of Nrf2-modulated genes in the human small airway epithelium is highly responsive to cigarette smoking

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an oxidant-responsive transcription factor known to induce detoxifying and antioxidant genes. Cigarette smoke, with its large oxidant content, is a major stress on the cells of small airway epithelium, which are vulnerable to oxidant damage. We assessed the role of cigarette smoke in activation of Nrf2 in the human small airway epithelium in vivo. Fiberoptic bronchoscopy was used to sample the small airway epithelium in healthy-nonsmoker and healthy-smoker, and gene expression was assessed using microarrays. Relative to nonsmokers, Nrf2 protein in the small airway epithelium of smokers was activated and localized in the nucleus. The human homologs of 201 known murine Nrf2-modulated genes were identified, and 13 highly smoking-responsive Nrf2-modulated genes were identified. Construction of an Nrf2 index to assess the expression levels of these 13 genes in the airway epithelium of smokers showed coordinate control, an observation confirmed by quantitative PCR. This coordinate level of expression of the 13 Nrf2-modulated genes was independent of smoking history or demographic parameters. The Nrf2 index was used to identify two novel Nrf2-modulated, smoking-responsive genes, pirin (PIR) and UDP glucuronosyltransferase 1-family polypeptide A4 (UGT1A4). Both genes were demonstrated to contain functional antioxidant response elements in the promoter region. These observations suggest that Nrf2 plays an important role in regulating cellular defenses against smoking in the highly vulnerable small airway epithelium cells, and that there is variability within the human population in the Nrf2 responsiveness to oxidant burden.

Oxidative stress and accelerated vascular aging: implications for cigarette smoking

Cigarette smoking is the major cause of preventable morbidity and mortality in the United States and constitutes a major risk factor for atherosclerotic vascular disease, including coronary artery disease and stroke. Increasing evidence supports the hypothesis that oxidative stress and inflammation provide the pathophysiological link between cigarette smoking and CAD. Previous studies have shown that cigarette smoke activates leukocytes to release reactive oxygen and nitrogen species (ROS/RNS) and secrete pro-inflammatory cytokines, increases the adherence of monocytes to the endothelium and elicits airway inflammation. Here we present an overview of the direct effects of water-soluble cigarette smoke constituents on endothelial function, vascular ROS production and inflammatory gene expression. The potential pathogenetic role of peroxynitrite formation, and downstream mechanisms including poly(ADP-ribose) polymerase (PARP) activation in cardiovascular complications in smokers are also discussed.

Alveolar epithelial and endothelial cell apoptosis in emphysema: what we know and what we need to know

Emphysema is mainly caused by cigarette smoking and is characterized by the loss of alveolar integrity and an enlargement of the alveolar space. However, mechanisms involved in its development are not fully understood. Alveolar cell apoptosis has been previously investigated in the lung of emphysematous subjects as a potential contributor to the loss of alveolar cell and has been found abnormally elevated. Though, mechanisms involved in the increased alveolar apoptosis that occurs in emphysema have now become a prolific field of research. Those mechanisms are reviewed here with special focus on how they affect cell viability and how they may be implicated in emphysema. Moreover, we suggest a model that integrates all those mechanisms to explain the increased alveolar apoptosis observed in emphysema. This review also includes some reflections and suggestions on the research to come.

Associations betweenXRCC1andERCC2polymorphisms and DNA damage in peripheral blood lymphocyte among coke oven workers

A wide variety of base damages and single-strand breaks formed by reactive oxygen species during metabolic activation of polycyclic aromatic hydrocarbons (PAHs) have been recognized to be involved in PAH carcinogenesis. In this study, alkaline comet assay was used to detect the DNA damage in peripheral blood lymphocytes among 143 coke-oven workers and 50 non-coke-oven workers, and the effects of genetic polymorphisms of XRCC1 and ERCC2 genes on DNA damage were evaluated. The olive tail moment was significantly higher in coke-oven workers than in non-coke-oven workers (2.6, 95% CI=2.1-3.3 versus 1.0, 95% CI=0.8-1.2, p<0.01), and significant correlation between ln-transformed urinary 1-OHP and ln-transformed olive tail moment was found in total population (n=193, Pearson's r=0.393, p<0.001) and in coke-oven workers (n=143, Pearson's r=0.224, p=0.007). The olive tail moment was significantly higher in coke-oven workers with GA genotype of G27466A polymorphism of XRCC1 than those with GG genotype (4.6, 95% CI=2.5-8.7 versus 2.4, 95% CI=1.9-2.9, p<0.01 with adjustment for covariates). No significant associations between C26304T, G28152A and G36189A polymorphisms of XRCC1 and G23591A and A35931C polymorphisms of ERCC2 and olive tail moment were found in both groups. The study showed that the alkaline comet assay is a suitable biomarker in the detection of DNA damage among coke-oven workers and it suggested that the A allele of G27466A polymorphism of XRCC1 may be associated with decreased DNA repair capacity toward PAH-induced base damage and strand breaks.

Serum uric Acid in smokers

OBJECTIVES

To demonstrate the possible effect of smoking on serum uric acid.

METHODS

Subjects enrolled in study were divided into two groups; nonsmokers and smokers, each with 60 male volunteers of the same social class and dietary habit without history of alcohol consumption, diabetes mellitus, hyperuricemia and gout, renal, joint, lung or heart diseases. Fasting blood and random urine samples were obtained from both groups for measurement of uric acid and creatinine. Calculation of both urine uric acid/urine creatinine ratio and fraction excretion of uric acid were done. The results were statistically evaluated by standard statistical methods.

RESULTS

No significant differences in the age, serum creatinine, spot urine uric acid/urine creatinine ratio and fraction excretion of uric acid between the two groups, serum uric acid was significantly lower in smokers. In smokers there was significant negative correlation of smoking status (average number of cigarette smoked/day, duration of smoking and cumulative amount of smoking) with serum uric acid.

CONCLUSION

After exclusion of other factors affecting uric acid level, the significant low serum uric acid level in smokers was attributed to reduce endogenous production as a result of chronic exposure to cigarette smoke that is a significant source of oxidative stress. As this reduction is proportionate with smoking status and predisposes to cardiovascular disease, it is, therefore, recommended for smokers to stop or reduce smoking and introduce serum uric acid estimation as routine test since its cheap and simple to reflect their antioxidant level.

KEYWORDS

Smokers; Uric acid; CVD.

Cigarette smoke-induced oxidative stress suppresses generation of dendritic cell IL-12 and IL-23 through ERK-dependent pathways

IL-12p70, a heterodimer composed of p35 and p40 subunits, is a key polarizing cytokine produced by maturing dendritic cells (DCs). We report that cigarette smoke extract (CSE), an extract of soluble cigarette smoke components, suppresses both p35 and p40 production by LPS or CD40L-matured DCs. Suppression of IL-12p70 production from maturing DCs was not observed in the presence of nicotine concentrations achievable in CSE or in the circulation of smokers. The suppressed IL-12p70 protein production by CSE-conditioned DCs was restored by pretreatment of DCs or CSE with the antioxidants N-acetylcysteine and catalase. Inhibition of DC IL-12p70 by CSE required activation of ERK-dependent pathways, since inhibition of ERK abrogated the suppressive effect of CSE on IL-12 secretion. Oxidative stress and sustained ERK phosphorylation by CSE enhanced nuclear levels of the p40 transcriptional repressor c-fos in both immature and maturing DCs. Suppression of the p40 subunit by CSE also resulted in diminished production of IL-23 protein by maturing DCs. Using a murine model of chronic cigarette smoke exposure, we observed that systemic and lung DCs from mice "smokers" produced significantly less IL-12p70 and p40 protein upon maturation. This inhibitory effect was selective, since production of TNF-alpha during DC maturation was enhanced in the smokers. These data imply that oxidative stress generated by cigarette smoke exposure suppresses the generation of key cytokines by maturing DCs through the activation of ERK-dependent pathways. Some of the cigarette smoke-induced inhibitory effects on DC function may be mitigated by antioxidants.

Cigarette smoke induces endoplasmic reticulum stress and the unfolded protein response in normal and malignant human lung cells

Background

Although lung cancer is among the few malignancies for which we know the primary etiological agent (i.e., cigarette smoke), a precise understanding of the temporal sequence of events that drive tumor progression remains elusive. In addition to finding that cigarette smoke (CS) impacts the functioning of key pathways with significant roles in redox homeostasis, xenobiotic detoxification, cell cycle control, and endoplasmic reticulum (ER) functioning, our data highlighted a defensive role for the unfolded protein response (UPR) program. The UPR promotes cell survival by reducing the accumulation of aberrantly folded proteins through translation arrest, production of chaperone proteins, and increased degradation. Importance of the UPR in maintaining tissue health is evidenced by the fact that a chronic increase in defective protein structures plays a pathogenic role in diabetes, cardiovascular disease, Alzheimer's and Parkinson's syndromes, and cancer.

Methods

Gene and protein expression changes in CS exposed human cell cultures were monitored by high-density microarrays and Western blot analysis. Tissue arrays containing samples from 110 lung cancers were probed with antibodies to proteins of interest using immunohistochemistry.

Results

We show that: 1) CS induces ER stress and activates components of the UPR; 2) reactive species in CS that promote oxidative stress are primarily responsible for UPR activation; 3) CS exposure results in increased expression of several genes with significant roles in attenuating oxidative stress; and 4) several major UPR regulators are increased either in expression (i.e., BiP and eIF2α) or phosphorylation (i.e., phospho-eIF2α) in a majority of human lung cancers.

Conclusion

These data indicate that chronic ER stress and recruitment of one or more UPR effector arms upon exposure to CS may play a pivotal role in the etiology or progression of lung cancers, and that phospho-eIF2α and BiP may have diagnostic and/or therapeutic potential. Furthermore, we speculate that upregulation of UPR regulators (in particular BiP) may provide a pro-survival advantage by increasing resistance to cytotoxic stresses such as hypoxia and chemotherapeutic drugs, and that UPR induction is a potential mechanism that could be attenuated or reversed resulting in a more efficacious treatment strategy for lung cancer.

Protective effect of Sesbania grandiflora against cigarette smoke-induced oxidative damage in rats

Sesbania grandiflora, commonly known as "sesbania" and "agathi," is widely used in Indian traditional medicine for the treatment of a broad spectrum of diseases. In the present study, we evaluated the possible protective effect of an aqueous suspension of S. grandiflora (ASSG) leaves against cigarette smoke-induced oxidative damage in rats. Adult Wistar-Kyoto rats were exposed to cigarette smoke for a period of 90 days and treated with ASSG (1,000 mg/kg of body weight/day, p.o) for a period of 3 weeks. The levels of protein carbonyl and activities of cytochrome P450, NADPH oxidase, and xanthine oxidase were significantly increased, whereas the levels of total thiol, protein thiol, non-protein thiol, nucleic acids, and tissue protein were significantly reduced in lung, liver, kidney, and heart of cigarette smoke-exposed rats as compared with control rats. Plasma nitric oxide levels, measured as nitrite plus nitrate, were significantly increased in cigarette smoke-exposed rats when compared to the control rats. The above changes were ameliorated to near control in the treatment group. These results suggest that supplementation with ASSG reversed the cigarette smoke-induced oxidative damage in rats through its antioxidant potential. These results provide further support for the traditional use of S. grandiflora in the treatment of smoke-related diseases.

Evaluation of status of toxic metals in biological samples of diabetes mellitus patients

There is accumulating evidence that the metabolism of several trace elements is altered in diabetes mellitus and that these nutrients might have specific roles in the pathogenesis and progress of this disease. The aim of present study was to compare the level of toxic elements, lead (Pb), cadmium (Cd), and arsenic (As) in biological samples (whole blood, urine, and scalp hair) of patients having diabetes mellitus type-2 age ranged (31-60) (n=238), with those of age matched non-diabetics (ND) as control subjects (n=196), of both genders. The concentrations of elements were measured by means of an atomic absorption spectrophotometer after microwave-assisted acid digestion. The validity and accuracy was checked by conventional wet acid digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of 98.1-99.4% of certified values. The results of this study showed that the mean values of Pb, Cd and, As were significantly higher in scalp hair samples of smoker and non-smoker diabetic patients as compared to control subjects (p<0.001). The concentration of understudy toxic metals was also high in blood and urine samples of DM patient but difference was more significant in smoker DM patients. These results are consistent with those obtained in other studies, confirming that toxic metals may play a role in the development of diabetes mellitus.

Determination of cadmium in whole blood and scalp hair samples of Pakistani male lung cancer patients by electrothermal atomic absorption spectrometer

A large number of epidemiologic studies have been undertaken to identify potential risk factors for cancer, amongst which the association with cadmium has received considerable attention. There is compelling evidence in support of positive associations between cadmium and risk of lung cancer. In present study we measured the concentration of Cd in whole blood and scalp hair samples of 120 male lung cancer patients (smokers) and 150 controls or referents (smokers and nonsmokers) from different cities of Pakistan. Both referents and patients were of same age group (ranged 40-70 years), socio-economic status, localities and dietary habits. The scalp hair and whole blood samples were oxidized by 65% nitric acid: 30% hydrogen peroxide (2:1) ratio in microwave oven. To check the validity of the proposed method, a conventional wet acid digestion method was used to obtain total Cd concentration in certified samples of human hair BCR 397 and Clincheck control-lyophilized human whole blood. All digests were analyzed for Cd concentration by electrothermal atomic absorption spectrometer (ETAAS). The results of this study showed that the average Cd concentration was higher in the blood and scalp hair of lung cancer patients at different stages as compared to controls (p<001). The smoker referents have high level of Cd in both biological samples as compared to nonsmoker subjects. These results illustrate that the patients who continued smoking after confirmed diagnosis of lung cancer have 34.2-67.26 and 22.4-57.3% more Cd in blood samples and scalp hair than lung cancer patients who cease smoking. This study is compelling evidence in support of positive associations between cadmium, cigarette smoking and lung cancer risk.

Frontiers in emphysema research

Chronic obstructive pulmonary disease (COPD) is a complex inflammatory disease with a myriad of pulmonary and nonpulmonary disease manifestations. COPD is a heterogeneous disease consisting of emphysematous destruction, airway inflammation, remodeling, and obstruction. Once conceptualized as a unidimensional disease isolated to the lung, it is now recognized to have significant systemic manifestations, such as osteoporosis, cardiovascular disease, and skeletal muscle wasting. As the clinical phenotypic expressions of COPD become more precisely characterized, so does the pathogenesis of this disease. Great strides are now being made in our understanding of genetic susceptibility, airway inflammation, the immune response to cigarette smoke, and inflammatory biomarkers. This review will discuss the most recent progress on selected topics in COPD pathogenesis, inflammation, and genetics. With time, we hope to expand our current understanding to predict who will develop disease and who will not, and why some patients develop particular disease phenotypes. In addition, we hope to clarify the inflammatory mechanisms involved in order to develop novel therapies and identify disease biomarkers that will lead to better tools for monitoring disease activity. Finally, we hope to develop treatments aimed at lung regeneration and repair, to reverse lung damage that has already occurred. We are optimistic that novel therapies like gene therapy and advanced antiinflammatory agents will be in our future. Judging by the progress made in the last decade, these tools may soon become a reality.

Association between plasma BPDE-Alb adduct concentrations and DNA damage of peripheral blood lymphocytes among coke oven workers

OBJECTIVES

Coke oven emissions (COE) containing polycyclic aromatic hydrocarbons (PAHs) can induce both benzo[a]pyrene-r-7, t-8, t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts and DNA damage. However, the relation between these biomarkers for early biological effects is not well documented in coke oven workers.

METHODS

In this study, the authors recruited 207 male workers exposed to COE and 102 controls not exposed to COE in the same steel plant in northern China. They measured BPDE-Alb adduct concentrations in plasma with reverse-phase high performance liquid chromatography and DNA damage in peripheral blood lymphocytes with alkaline comet assay.

RESULTS

The results showed that the median concentration of BPDE-Alb adducts in the exposed group (34.36 fmol/mg albumin) was significantly higher than that in the control group (21.90 fmol/mg albumin, p = 0.012). The mean Olive tail moment (Olive TM) of DNA damage in the exposed and control groups were 1.20 and 0.63, respectively (p = 0.000). Multivariate logistic regression analysis revealed that the odds ratio (OR) for BPDE-Alb adduct and Olive TM associated with the exposure were 1.72 (95% CI 1.06 to 2.81) and 1.96 (95% CI 1.20 to 3.19), respectively. These results show significant correlations between the concentrations of BPDE-Alb adduct and Olive TM levels in exposed group (r = 0.235, p = 0.001) but not in control group (r = 0.093, p = 0.353).

CONCLUSION

The results suggest that occupational exposure to COE may induce both BPDE-Alb adducts and DNA damage in the lymphocytes of coke oven workers and that these two markers are useful for monitoring exposure to COE in the workplace.

Cigarette smoking and prostate cancer-specific mortality following diagnosis in middle-aged men

OBJECTIVE

The aim of this study was to examine associations of smoking at the time of diagnosis with the risk of prostate cancer death in a population-based cohort of men with prostate cancer.

METHODS

Data were from 752 prostate cancer patients aged 40-64 years, who were enrolled in a case-control study and under long-term follow-up for mortality. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between smoking and prostate cancer-specific and other cause mortality.

RESULTS

Compared to never smoking, smoking at the time of diagnosis was associated with a significant increase in risk of prostate cancer-specific mortality. After controlling for demographic characteristics, Gleason grade, stage at diagnosis, and primary treatment, the HR was 2.66 (95% CI: 1.10-6.43).

CONCLUSIONS

Smoking at the time of diagnosis, independent of key clinical prognostic factors, is associated with an increased risk of prostate cancer death.

Smoking, aging and the centenarians

The smoke of cigarettes represents an important accelerator of the aging process, both directly through complex mechanisms mediated prevalently by excessive formation of free radicals, and indirectly by favoring the appearance of various pathologies in which smoke is a recognized risk factor. This means that smoke compromises not only life expectancy, but also the quality of the life, favoring the occurrence of non-autosufficiency. Smoking is an important risk factor for many diseases, such as cancer, cardiovascular and respiratory diseases. These are also the main causes of death in the industrialized Countries, where the habit of smoking is also largely diffused. Non-smokers have a much higher life expectancy than smokers, and the suspension of smoking is accompanied, even in the elderly, by an increase in the survival time due to the reduction of smoke-induced biological damage. Therefore, cigarette smoking is opposing the longevity, particularly the extreme one, as it is confirmed by the observations obtained on centenarians. Among them, smoking is extremely rare, and even when it occurs among them, it is correlated almost exclusively to bad health conditions and non-autosufficiency, indicating that it compromises health status and the quality of life even in extremely long living subjects. Considering the demonstrated beneficial effects of suspension of smoking, all practitioners and geriatricians in particular, should promote the abstinence from smoking as a behavioral norm for a correct life style. Non-smokers can delay the appearance of diseases and of the aging process, thus attaining longevity; further, non-smoking habit allows genetically predisposed subjects to reach the extreme longevity and maintain an acceptable health status and autosufficiency.

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.

XRCC1, XRCC3, and XPD polymorphisms as modifiers of the effect of smoking and alcohol on colorectal adenoma risk

Using a sigmoidoscopy-based case-control study (753 cases, 799 controls) in Los Angeles County, we investigated the potential modifier role in the effect of alcohol and smoking of single-nucleotide polymorphisms (SNP) in three DNA repair genes, XRCC1 (Arg194Trp and Arg399Gln), XRCC3 (Thr241Met), and XPD (Lys751Gln). We have previously reported an inverse association between the XRCC1 codon 399 SNP and adenoma risk among these subjects. We now report that subjects with the XPD Gln/Gln genotype were inversely associated with adenoma risk [odds ratio (OR), 0.7; 95% confidence interval (95% CI), 0.5-1.0] when compared with subjects with the Lys/Lys and Lys/Gln genotypes combined. This association differed between different ethnic groups (gene x race heterogeneity likelihood ratio test, P = 0.009), with a stronger inverse association among Latinos (OR, 0.1; 95% CI, 0.01-0.5) than among non-Latinos (OR, 0.9; 95% CI, 0.-1.3). We found no evidence of an XRCC3 x smoking or alcohol interaction or an XRCC1 x alcohol interaction. Instead, our data supported an XRCC1 x smoking interaction (P = 0.048). Whereas XPD did not modify the effect of smoking, our data suggested an XPD x alcohol interaction. Analyses ignoring XPD showed no association between alcohol intake and adenoma prevalence; however, among carriers of the codon 751 Gln/Gln genotype, we found a significant positive association (OR, 2.5; 95% CI, 1.2-5.2 for ever drinkers; test of interaction P = 0.04). Our data suggest that the effects of smoking and alcohol may vary depending on the genetic background of proteins that participate in the base excision repair and nucleotide excision repair pathways.

Enhanced lipid peroxidation and nitric oxide products with deranged antioxidant status in patients with head and neck squamous cell carcinoma

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) can function both as initiators and promoters in carcinogenesis. Antioxidants provide protection against cellular and molecular damage caused by ROS and RNS. We conducted a study to evaluate the levels of lipid peroxidation products, nitric oxide (NO) products and antioxidants in patients with head and neck squamous cell carcinoma (HNSCC). Fifty one HNSCC patients, 33 healthy tobacco smokers/chewers as tobacco user controls, and 37 non-smokers/chewers as normal controls were recruited for this study. Lipid peroxidation products, NO products and antioxidants were measured using spectrophotometric methods. Lipid peroxidation products, including lipid hydroperoxide (LHP) and malondialdehyde (MDA), nitric oxide (NO) products, including nitrite (NO(2)(-)), nitrate (NO(3)(-)), and total nitrite (TNO(2)(-)) were found to be significantly elevated with a concomitant depletion of antioxidants in HNSCC patients as compared to tobacco users and normal controls. These derangements were also evident albeit to a lesser degree in tobacco users as compared to normal controls. Results from this study demonstrate a potential involvement of both ROS and RNS in the pathogenesis of HNSCC and also illustrate the risk of ROS/RNS induced damage healthy tobacco users are exposed to, implicating their higher risk for upper aerodigestive tract cancer.

Chemoprevention of smoke-induced alopecia in mice by oral administration of L-cystine and vitamin B6

BACKGROUND

We previously demonstrated that high doses of environmental cigarette smoke (ECS) induce alopecia in mice. This effect was prevented by the oral administration of N-acetylcysteine (NAC), an analogue and precursor of L-cysteine and reduced glutathione.

OBJECTIVES

The present study aimed at assessing whether L-cystine, the oxidized form of L-cysteine, which is a key hair component, may behave like NAC in inhibiting ECS-induced alopecia and modulating the mechanisms responsible for this condition.

METHODS

C57BL/6 mice were exposed whole-body to ECS in a smoking machine. Groups of mice received in the diet, at three dose levels, a mixture of L-cystine with vitamin B6, which plays a role in L-cystine incorporation in hair cells. Occurrence of alopecia areas and apoptosis of hair bulb cells were evaluated for up to 6 months of exposure, and the time course induction of micronucleated erythrocytes in peripheral blood was investigated.

RESULTS

The frequency of micronucleated erythrocytes was increased by ECS, irrespective of treatment with L-cystine/vitamin B6. ECS-induced alopecia and apoptosis of hair bulb cells in all exposed mice. L-Cystine/vitamin B6 inhibited alopecia in a dose-dependent fashion.

CONCLUSIONS

High-dose ECS induces apoptosis-related alopecia in mice, and oral administration of L-cystine/vitamin B6 is an effective preventive treatment.