Differential lung inflammation and injury with tobacco smoke exposure in Wistar Kyoto and spontaneously hypertensive rats.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide and has been associated with periods of intense lung inflammation. The objective of this study was to characterize whether similar rat strains, possessing different genetic predispositions, might play a role in exacerbating the pathophysiology of COPD-like cellular and structural changes with progressive 12-week exposure to tobacco smoke (TS). Normotensive Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats were compared. MATERIALS AND METHODS: WKY and SH rats were exposed to filtered air or to tobacco smoke at a particulate concentration of 80 mg/m3 for 4, 8, or 12 weeks. Necropsy was performed 24 h after the last exposure to obtain cells by bronchoalveolar lavage for total cell and differential counts. Scoring of lung tissues and immunohistochemical staining for M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages were performed on paraffin-embedded lung sections. RESULTS AND DISCUSSION: With progressive exposure, TS-exposed SH rats demonstrated significant airspace enlargement, mucin production, and lung inflammation compared to their FA control and TS-matched WKY rats. Moreover, SH rats also demonstrated increased expression of the M1 marker in alveolar macrophages compared to FA control, as well as the M2 marker compared to controls and TS-exposed WKY rats. CONCLUSION: The progressive tobacco smoke exposure contributes to persistent lung injury and inflammation that can be significantly enhanced by rat strain susceptibility in the genesis of COPD.

Neutrophil extracellular traps produced during inflammation awaken dormant cancer cells in mice.

Cancer cells from a primary tumor can disseminate to other tissues, remaining dormant and clinically undetectable for many years. Little is known about the cues that cause these dormant cells to awaken, resume proliferating, and develop into metastases. Studying mouse models, we found that sustained lung inflammation caused by tobacco smoke exposure or nasal instillation of lipopolysaccharide converted disseminated, dormant cancer cells to aggressively growing metastases. Sustained inflammation induced the formation of neutrophil extracellular traps (NETs), and these were required for awakening dormant cancer. Mechanistic analysis revealed that two NET-associated proteases, neutrophil elastase and matrix metalloproteinase 9, sequentially cleaved laminin. The proteolytically remodeled laminin induced proliferation of dormant cancer cells by activating integrin α3ß1 signaling. Antibodies against NET-remodeled laminin prevented awakening of dormant cells. Therapies aimed at preventing dormant cell awakening could potentially prolong the survival of cancer patients.

Repeated Iron-Soot Exposure and Nose-to-brain Transport of Inhaled Ultrafine Particles.

Particulate exposure has been implicated in the development of a number of neurological maladies such as multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, and idiopathic Parkinson's disease. Only a few studies have focused on the olfactory pathway as a portal through which combustion-generated particles may enter the brain. The primary objective of this study was to define the deposition, uptake, and transport of inhaled ultrafine iron-soot particles in the nasal cavities of mice to determine whether combustion-generated nanoparticles reach the olfactory bulb via the olfactory epithelium and nerve fascicles. Adult female C57B6 mice were exposed to iron-soot combustion particles at a concentration of 200 µg/m3, which included 40 µg/m3 of iron oxide nanoparticles. Mice were exposed for 6 hr/day, 5 days/week for 5 consecutive weeks (25 total exposure days). Our findings visually demonstrate that inhaled ultrafine iron-soot reached the brain via the olfactory nerves and was associated with indicators of neural inflammation.

Size-Dependent Deposition, Translocation, and Microglial Activation of Inhaled Silver Nanoparticles in the Rodent Nose and Brain.

BACKGROUND: Silver nanoparticles (AgNP) are present in personal, commercial, and industrial products, which are often aerosolized. Current understanding of the deposition, translocation, and health-related impacts of AgNP inhalation is limited. OBJECTIVES: We determined a) the deposition and retention of inhaled Ag in the nasal cavity from nose-only exposure; b) the timing for Ag translocation to and retention/clearance in the olfactory bulb (OB); and c) whether the presence of Ag in the OB affects microglial activity. METHODS: Male Sprague-Dawley rats were exposed nose-only to citrate-buffered 20- or 110-nm AgNP (C20 or C110, respectively) or citrate buffer alone for 6 hr. The nasal cavity and OB were examined for the presence of Ag and for biological responses up to 56 days post-exposure (8 weeks). RESULTS: The highest nasal Ag deposition was observed on Day 0 for both AgNP sizes. Inhalation of aerosolized C20 resulted in rapid translocation of Ag to the OB and in microglial activation at Days 0, 1, and 7. In contrast, inhalation of C110 resulted in a gradual but progressive transport of Ag to and retention in the OB, with a trend for microglial activation to variably be above control. CONCLUSIONS: The results of this study show that after rats experienced a 6-hr inhalation exposure to 20- and 110-nm AgNP at a single point in time, Ag deposition in the nose, the rate of translocation to the brain, and subsequent microglial activation in the OB differed depending on AgNP size and time since exposure. Citation: Patchin ES, Anderson DS, Silva RM, Uyeminami DL, Scott GM, Guo T, Van Winkle LS, Pinkerton KE. 2016. Size-dependent deposition, translocation, and microglial activation of inhaled silver nanoparticles in the rodent nose and brain. Environ Health Perspect 124:1870-1875; http://dx.doi.org/10.1289/EHP234.

HDAC3 mediates smoking-induced pancreatic cancer.

Smoking is a major risk factor for developing pancreatic adenocarcinoma (PDAC); however, little is known about the mechanisms involved. Here we employed a genetic animal model of early stages of PDAC that overexpresses oncogenic Kras in the pancreas to investigate the mechanisms of smoking-induced promotion of the disease in vivo. We confirmed the regulation of the interactions between the tumor microenvironment cells using in vitro cellular systems. Aerial exposure to cigarette smoke stimulated development of pancreatic intraepithelial neaoplasia (PanIN) lesions associated with a tumor microenvironment-containing features of human PDAC including fibrosis, activated stellate cells, M2-macrophages and markers of epithelial-mesenchymal transition (EMT). The pro-cancer effects of smoking were prevented by Histone Deacetylase HDAC I/II inhibitor Saha. Smoking decreased histone acetylation associated with recruitment of and phenotypic changes in macrophages; which in turn, stimulated survival and induction of EMT of the pre-cancer and cancer cells. The interaction between the cancer cells and macrophages is mediated by IL-6 produced under the regulation of HDAC3 translocation to the nucleus in the cancer cells. Pharmacological and molecular inhibitions of HDAC3 decreased IL-6 levels in cancer cells. IL-6 stimulated the macrophage phenotype change through regulation of the IL-4 receptor level of the macrophage. This study demonstrates a novel pathway of interaction between cancer cells and tumor promoting macrophages involving HDAC3 and IL-6. It further demonstrates that targeting HDAC3 prevents progression of the disease and could provide a strategy for treating the disease considering that the HDAC inhibitor we used is FDA approved for a different disease.

Single-Cell Mechanics Provides an Effective Means To Probe in Vivo Interactions between Alveolar Macrophages and Silver Nanoparticles.

Single-cell mechanics, derived from atomic force microscopy-based technology, provides a new and effective means to investigate nanomaterial-cell interactions upon in vivo exposure. Lung macrophages represent initial and important responses upon introducing nanoparticles into the respiratory tract, as well as particle clearance with time. Cellular mechanics has previously proven effective to probe in vitro nanomaterial-cell interactions. This study extends technology further to probe the interactions between primary alveolar macrophages (AM) and silver nanoparticles (AgNPs) upon in vivo exposure. Two types of AgNPs, 20 and 110 nm, were instilled to rat lung at 0.5 mg AgNPs/kg body weight, and allowed 24 h interaction. The consequences of these interactions were investigated by harvesting the primary AMs while maintaining their biological status. Cellular mechanics measurements revealed the diverse responses among AM cells, due to variations in AgNP uptake and oxidative dissolving into Ag(+). Three major responses are evident: zero to low uptake that does not alter cellular mechanics, intracellular accumulation of AgNPs trigger cytoskeleton rearrangement resulting in the stiffening of mechanics, and damage of cytoskeleton that softens the mechanical profile. These effects were confirmed using confocal imaging of F-actin and measurements of reactive oxygen species production. More detailed intracellular interactions will also be discussed on the basis of this study in conjunction with prior knowledge of AgNP toxicity.

Influence of particle size on persistence and clearance of aerosolized silver nanoparticles in the rat lung.

The growing use of silver nanoparticles (AgNPs) in consumer products raises concerns about potential health effects. This study investigated the persistence and clearance of 2 different size AgNPs (20 and 110 nm) delivered to rats by single nose-only aerosol exposures (6 h) of 7.2 and 5.4 mg/m(3), respectively. Rat lung tissue was assessed for silver accumulations using inductively-coupled plasma mass spectrometry (ICP-MS), autometallography, and enhanced dark field microscopy. Involvement of tissue macrophages was assessed by scoring of silver staining in bronchoalveolar lavage fluid (BALF). Silver was abundant in most macrophages at 1 day post-exposure. The group exposed to 20 nm AgNP had the greatest number of silver positive BALF macrophages at 56 days post-exposure. While there was a significant decrease in the amount of silver in lung tissue at 56 days post-exposure compared with 1 day following exposure, at least 33% of the initial delivered dose was still present for both AgNPs. Regardless of particle size, silver was predominantly localized within the terminal bronchial/alveolar duct junction region of the lung associated with extracellular matrix and within epithelial cells. Inhalation of both 20 and 110 nm AgNPs resulted in a persistence of silver in the lung at 56 days post-exposure and local deposition as well as accumulation of silver at the terminal bronchiole alveolar duct junction. Further the smaller particles, 20 nm AgNP, produced a greater silver burden in BALF macrophages as well as greater persistence of silver positive macrophages at later timepoints (21 and 56 days).

Bioactive lipid profiling reveals drug target engagement of a soluble epoxide hydrolase inhibitor in a murine model of tobacco smoke exposure.

The inflammatory process underlying chronic obstructive pulmonary disease (COPD) may be caused by tobacco smoke (TS) exposure. Previous studies show that epoxyeicosatrienoic acids (EETs) possess promising anti-inflammatory properties, therefore stabilization of EETs and other fatty acid epoxides through inhibition of soluble epoxide hydrolase (sEH) was investigated in mouse models of acute and sub-chronic inflammation caused by TS exposure. During the entire TS exposure, the potent sEH inhibitor 1-(1-methylsulfonyl-piperidin-4-yl)-3-(4-trifluoromethoxy-phenyl)-urea (TUPS) was given via drinking water. To assess drug target engagement of TUPS, a tandem mass spectrometry method was used for bioactive lipid profiling of a broad range of fatty acid metabolites, including EETs, and their corresponding diols (DHETs) derived from arachidonic acid, as well as epoxides and diols derived from other fatty acids. Several, but not all, plasma epoxide/diol ratios increased in mice treated with sEH inhibitor, compared to non-treated mice suggesting a wider role for sEH involving more fatty acid precursors besides arachidonic acid. This study supports qualitative use of epoxide/diol ratios explored by bioactive lipid profiling to indicate drug target engagement in mouse models of TS exposure relevant to COPD, which may have ramifications for future therapeutic interventions of sEH.

Developmental exposure to second-hand smoke increases adult atherogenesis and alters mitochondrial DNA copy number and deletions in apoE(-/-) mice.

Cardiovascular disease is a major cause of morbidity and mortality in the United States. While many studies have focused upon the effects of adult second-hand smoke exposure on cardiovascular disease development, disease development occurs over decades and is likely influenced by childhood exposure. The impacts of in utero versus neonatal second-hand smoke exposure on adult atherosclerotic disease development are not known. The objective of the current study was to determine the effects of in utero versus neonatal exposure to a low dose (1 mg/m(3) total suspended particulate) of second-hand smoke on adult atherosclerotic lesion development using the apolipoprotein E null mouse model. Consequently, apolipoprotein E null mice were exposed to either filtered air or second-hand smoke: (i) in utero from gestation days 1-19, or (ii) from birth until 3 weeks of age (neonatal). Subsequently, all animals were exposed to filtered air and sacrificed at 12-14 weeks of age. Oil red-O staining of whole aortas, measures of mitochondrial damage, and oxidative stress were performed. Results show that both in utero and neonatal second-hand smoke exposure significantly increased adult atherogenesis in mice compared to filtered air controls. These changes were associated with changes in aconitase and mitochondrial superoxide dismutase activities consistent with increased oxidative stress in the aorta, changes in mitochondrial DNA copy number and deletion levels. These studies show that in utero or neonatal exposure to second-hand smoke significantly influences adult atherosclerotic lesion development and results in significant alterations to the mitochondrion and its genome that may contribute to atherogenesis.

Use of a soluble epoxide hydrolase inhibitor in smoke-induced chronic obstructive pulmonary disease.

Tobacco smoke-induced chronic obstructive pulmonary disease (COPD) is a prolonged inflammatory condition of the lungs characterized by progressive and largely irreversible airflow limitation attributable to a number of pathologic mechanisms, including bronchitis, bronchiolitis, emphysema, mucus plugging, pulmonary hypertension, and small-airway obstruction. Soluble epoxide hydrolase inhibitors (sEHIs) demonstrated anti-inflammatory properties in a rat model after acute exposure to tobacco smoke. We compared the efficacy of sEHI t-TUCB (trans-4-{4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid) and the phosphodiesterase-4 (PDE4) inhibitor Rolipram (Biomol International, Enzo Life Sciences, Farmingdale, NY) to reduce lung injury and inflammation after subacute exposure to tobacco smoke over a period of 4 weeks. Pulmonary physiology, bronchoalveolar lavage, cytokine production, and histopathology were analyzed to determine the efficacy of sEHI and Rolipram to ameliorate tobacco smoke-induced inflammation and injury in the spontaneously hypertensive rat. Both t-TUCB and Rolipram inhibited neutrophil elevation in bronchoalveolar lavage. sEHI t-TUCB suppressed IFN-γ, while improving lung function by reducing tobacco smoke-induced total respiratory resistance and tissue damping (small-airway and peripheral tissue resistance). Increases in tobacco smoke-induced alveolar airspace size were attenuated by t-TUCB. Rolipram inhibited the production of airway mucus. Both t-TUCB and Rolipram inhibited vascular remodeling-related growth factor. These findings suggest that sEHI t-TUCB has therapeutic potential for treating COPD by improving lung function and attenuating the lung inflammation and emphysematous changes caused by tobacco smoke. To the best of our knowledge, this is the first report to demonstrate that sEHI exerts significant protective effects after repeated, subacute tobacco smoke-induced lung injury in a rat model of COPD.

Particulate matter in cigarette smoke alters iron homeostasis to produce a biological effect.

RATIONALE: Lung injury after cigarette smoking is related to particle retention. Iron accumulates with the deposition of these particles. OBJECTIVES: We tested the postulate that (1) injury after smoking correlates with exposure to the particulate fraction of cigarette smoke, (2) these particles alter iron homeostasis, triggering metal accumulation, and (3) this alteration in iron homeostasis affects oxidative stress and inflammation. METHODS: Rats and human respiratory epithelial cells were exposed to cigarette smoke, filtered cigarette smoke, and cigarette smoke condensate (the particulate fraction of smoke), and indices of iron homeostasis, oxidative stress, and inflammatory injury were determined. Comparable measures were also evaluated in nonsmokers and smokers. MEASUREMENTS AND MAIN RESULTS: After exposure of rats to cigarette smoke, increased lavage concentrations of iron and ferritin, serum ferritin levels, and nonheme iron concentrations in the lung and liver tissue all increased. Lavage ascorbate concentrations were decreased, supporting an oxidative stress. After filtering of the cigarette smoke to remove particles, most of these changes were reversed. Exposure of cultured respiratory epithelial cells to cigarette smoke condensate caused a similar accumulation of iron, metal-dependent oxidative stress, and increased IL-8 release. Lavage samples in healthy smokers and smoking patients with chronic obstructive pulmonary disease revealed elevated concentrations of both iron and ferritin relative to healthy nonsmokers. Lavage ascorbate decreased with cigarette smoking. Serum iron and ferritin levels among smokers were increased, supporting systemic accumulation of this metal after cigarette smoke exposure. CONCLUSIONS: We conclude that cigarette smoke particles alter iron homeostasis, both in the lung and systemically.

Nicotinic receptor involvement in antinociception induced by exposure to cigarette smoke.

Direct exposure of rats to tobacco smoke induces antinociception. We presently investigated if this antinociception is mediated via nicotinic and/or mu-opioid receptors. Adult male rats were surgically implanted with Alzet osmotic minipumps that delivered either saline (control), the nicotinic antagonist mecamylamine, or the opiate antagonist naltrexone (3 mg/kg/day i.v. for 21 days). Nocifensive responses were assessed on alternate days using tail-flick reflex latency (TFL) over a 3-week period. During the second week, the rats were exposed to concentrated cigarette smoke in an environmental chamber for 6 h/day for 5 consecutive days; a control group was similarly exposed to filtered cigarette smoke. Rats receiving mecamylamine and naltrexone exhibited a significant weight loss after the first day of infusion. All treatment groups additionally exhibited significant weight loss during exposure to unfiltered or filtered smoke. The saline group exhibited significant antinociception on the first day of smoke exposure with rapid development of tolerance. The mecamylamine and naltrexone groups did not exhibit significant antinociception. Controls exposed to filtered smoke (with approximately 50% lower nicotine concentration) also exhibited significant analgesia on the first exposure day with rapid development of tolerance. Exposure to high levels of cigarette smoke, or to filtered smoke with a lower nicotine concentration in the vapor phase, induces antinociception with rapid development of tolerance. The antinociceptive effect appears to be mediated via nicotinic and mu-opioid receptors.

The chemopreventive effects of orally administered dexamethasone in Strain A/J mice following cessation of smoke exposure.

Male Strain A/J mice were exposed for 6 mo, 6 h/d, 5d/wk to a mixture of cigarette sidestream and mainstream smoke with an average total suspended particulate concentration of 156 mg/m3. They then were removed into air and fed diet AIN93M containing 0.5 mg/kg of dexamethasone until killed 4 mo later for the evaluation of lung tumor multiplicities. In animals kept in air, an average of 1.3 tumors per lung was found, and in tobacco-smoke-exposed animals the average number of tumors per lung was 2.2 (p<.05). Addition of dexamethasone to the diet reduced lung tumor multiplicities in the tobacco smoke exposed animals to 1.4 (64% of control values), not quite statistically significant. In animals not exposed to tobacco smoke, however, dexamethasone significantly decreased lung tumor multiplicities to 46% of control values. In animals injected with the tobacco-smoke-specific carcinogen NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone], dietary dexamethasone significantly reduced lung tumor multiplicities to 38% of controls. It is concluded that the dietary intake of dexamethasone against full tobacco smoke might show improved chemopreventive activity when combined with other agents.

Antinociception induced by chronic exposure of rats to cigarette smoke.

To investigate if chronic exposure to cigarette smoke induces analgesia, rats were exposed to concentrated cigarette smoke in an environmental chamber over four successive 5-day blocks (6 h/day), with 2 smoke-free days between blocks. A control group was exposed to room air. Tail flick latencies increased significantly (analgesia) during each smoke exposure block, with a relative decline in analgesia across blocks (tolerance) and a return to control levels during the first three smoke-free interludes while remaining higher after the conclusion of the 4-week exposure period. Mechanical (von Frey) withdrawal thresholds declined over time in smoke-exposed and control groups, with the smoke-exposed group showing significantly lower thresholds. Plasma nicotine reached 95.4 +/- 32 (S.D.) ng/ml at the end of weekly smoke exposure and declined to 44.9 +/- 10.6 ng/ml 24 h after withdrawal. Rats lost weight during smoke exposure and quickly regained weight during smoke-free interludes and at the cessation of smoke exposure. Analgesia may contribute to the initiation of smoking, and rapid reversal of the analgesic effect following acute exposure may contribute to the difficulty in quitting smoking.

The effects of dietary myoinositol on lung tumor development in tobacco smoke-exposed mice.

The purpose of these experiments was to investigate whether a diet containing myoinositol could prevent the development of tobacco smoke-induced lung tumors in strain A/J mice. In a positive control experiment, 1% and 3% of myoinositol in AIN-93 diet reduced the development of lung tumors induced by NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] by 69% and 75%. In animals exposed for 5 mo, 6 h/day, 5 days/wk, to a mixture of tobacco sidestream and mainstream smoke, and then fed myoinositol-containing diets once smoke exposure had ceased, no chemopreventive effect was observed. When animals were fed myoinositol during both tobacco smoke exposure and the recovery period, a slight but statistically not significant reduction in tumor multiplicities was found. It was concluded that myoinositol has less chemopreventive activity against the full complex mixture of tobacco smoke than it has against selected constituents such as NNK or benzo[a]pyrene.

Lung tumor response in strain a mice exposed to tobacco smoke: some dose-effect relationships.

Male strain A/J mice were exposed for 5 mo in a whole-body inhalation chamber to 3 different concentrations of a mixture of cigarette sidestream and mainstream smoke (99, 120, and 176 mg/m(3) of total suspended particulate material, TSP). After an additional 4-mo recovery period in air, lung tumor multiplicities and incidences were determined. The two highest smoke concentrations produced significantly more lung tumors than did the low dose and control groups, although the response to the high was slightly less than to the medium dose. Lung tumor incidences were in all three groups significantly higher than in controls. Lung displacement volume was increased in a dose-dependent manner, but morphometric analysis of the tissues failed to provide evidence for airspace enlargement. Plasma cotinine levels were dose-dependent and similar after 1-day and 5-day exposure. The shape of the dose-response curve and a comparison with previous data suggest that cigarette smoke is only a comparatively weak mouse lung carcinogen.

Chemoprevention of tobacco smoke-induced lung tumors by inhalation of an epigallocatechin gallate (EGCG) aerosol: a pilot study.

We investigated whether inhalation of aerosolized epigallocatechin gallate (EGCG) would prevent the development of lung tumors produced by tobacco smoke (TS). Male strain A/J mice were exposed for 5 mo, 6 h/day, 5 days/wk, to a mixture of tobacco sidestream and mainstream smoke. At the end of this exposure, 3 groups were formed: (a) mice exposed to TS and left undisturbed in air; (b) animals exposed to TS and given EGCG aerosol by nose-only inhalation for 30 min per session; and (c) animals exposed to TS and then exposed by nose-only inhalation to water aerosol without any EGCG (sham-exposed group). Three similar groups were formed from animals that previously had been kept in filtered air. In experiment 1, the EGCG concentration in the aerosol was 80 microg/L and administered 3 times a week and in experiment 2 it was 191 microg/L administered twice a week. Inhalation of EGCG did not modulate TS-induced tumorigenesis. In two accompanying positive control experiments, animals treated with the tobacco-specific carcinogen NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] were given the same EGCG or water aerosol treatment. In both experiments, EGCG aerosol significantly reduced lung tumor multiplicity by 20% to 30% However, exposure of NNK-treated animals to water solvent alone (sham exposure) produced an even greater reduction in tumor multiplicities (40%). A reduction of lung tumor multiplicities was also observed in animals exposed nose-only once or five times a week to either water aerosols or to filtered air. It is concluded that water-soluble chemopreventive agents that need to be ingested in comparatively high doses are not the most suitable candidates for administration by inhalation.

Inhibition of tobacco smoke-induced lung inflammation by a catalytic antioxidant.

Cigarette smokers experience airway inflammation and epithelial damage, the mechanisms of which are unknown. One potential cause may be free radicals either in tobacco smoke or produced during persistent inflammation. Inflammation may also be a driving force to cause airway epithelium to undergo changes leading to squamous cell metaplasia. To test whether tobacco smoke-induced inflammation could be reduced by a catalytic antioxidant, manganese(III)meso-tetrakis(N,N'-diethyl-1,3-imidazolium-2-yl) porphyrin (AEOL 10150) was given by intratracheal instillation to rats exposed to filtered air or tobacco smoke. Exposure to tobacco smoke for 2 d or 8 weeks (6 h/d, 3 d/week) significantly increased the number of cells recovered by bronchoalveolar lavage (BAL). AEOL 10150 significantly decreased BAL cell number in tobacco smoke-treated rats. Significant reductions in neutrophils were noted at 2 d and macrophages at 8 weeks. Lymphocytes were significantly reduced by AEOL 10150 at both time points. Squamous cell metaplasia following 8 weeks of tobacco smoke exposure was 12% of the total airway epithelial area in animals exposed to tobacco smoke without AEOL 10150, compared with 2% in animals exposed to tobacco smoke, but treated with AEOL 10150 (p <.05). We conclude that a synthetic catalytic antioxidant decreased the adverse effects of exposure to tobacco smoke.

Cigarette smoke exposure and hypercholesterolemia increase mitochondrial damage in cardiovascular tissues.

BACKGROUND: A shared feature among cardiovascular disease risk factors is increased oxidative stress. Because mitochondria are susceptible to damage mediated by oxidative stress, we hypothesized that risk factors (secondhand smoke and hypercholesterolemia) are associated with increased mitochondrial damage in cardiovascular tissues. METHODS AND RESULTS: Atherosclerotic lesion formation, mitochondrial DNA damage, protein nitration, and specific activities of mitochondrial proteins in cardiovascular tissues from age-matched C57 and apoE(-/-) mice exposed to filtered air or secondhand smoke were quantified. Both secondhand smoke and hypercholesterolemia were associated with significantly increased mitochondrial DNA damage and protein nitration. Tobacco smoke exposure also resulted in significantly decreased specific activities of mitochondrial enzymes. The combination of secondhand smoke and hypercholesterolemia resulted in increased atherosclerotic lesion formation and even greater levels of mitochondrial damage. CONCLUSIONS: These data are consistent with the hypothesis that cardiovascular disease risk factors cause mitochondrial damage and dysfunction.