Short-term exposure to aged and diluted sidestream cigarette smoke enhances ozone-induced lung injury in B6C3F1 mice.

To determine the effects of aged and diluted sidestream cigarette smoke (ADSS) as a surrogate of environmental tobacco smoke (ETS) on ozone-induced lung injury, male B6C3F1 mice were exposed to (1) filtered air (FA), (2) ADSS, (3) ozone, or (4) ADSS followed by ozone (ADSS/ozone). Exposure to ADSS at 30 mg/m3 of total suspended particulates (TSP) for 6 h/day for 3 days, followed by exposure to ozone at 0.5 ppm for 24 h was associated with a significant increase in the number of cells recovered by bronchoalveolar lavage (BAL) compared with exposure to ADSS alone or ozone alone. The proportion of neutrophils and lymphocytes, as well as total protein level in BAL, was also significantly elevated following ADSS/ozone exposure, when compared with all other groups. Within the centriacinar regions of the lungs, the percentage of proliferating cells identified by bromodeoxyuridine (BrdU) labeling was unchanged from control, following exposure to ADSS alone, but was significantly elevated following exposure to ozone (280% of control) and further augmented in a statistically significant manner in mice exposed to ADSS/ozone (402% of control). Following exposure to ozone or ADSS/ozone, the ability of alveolar macrophages (AM) to release interleukin (IL)-6 under lipopolysaccharide (LPS) stimulation was significantly decreased, while exposure to ADSS or ADSS/ozone caused a significantly increased release of tumor necrosis factor alpha from AM under LPS stimulation. We conclude that ADSS exposure enhances the sensitivity of animals to ozone-induced lung injury.     

Comparison of two in vitro models of cigarette smoke exposure

Cigarette smoke is associated with a high morbidity and mortality, and affects particularly the respiratory tract. Various in vitro models have been developed to study the effects of cigarette smoke on bronchial epithelial cells. To identify an adequate exposure model of cigarette smoke, we analysed the effects of cigarette smoke extract (CSE) and a smoking chamber on bronchial epithelial cells. The release of monocyte chemoattractant protein (MCP)-1, interleukin (IL)-10, and vascular endothelial growth factor (VEGF) was measured. Bronchial epithelial cells isolated from Sprague-Dawley rat (NRBE) were exposed to 3% CSE or air control every day for 3 days. In the second model, NRBE were placed in an air/liquid interface and exposed, in a smoking chamber, to whole smoke from 2 cigarettes, twice daily for 3 days. Levels of MCP-1, IL-10, and VEGF were measured by enzyme-linked immunosorbent assay (ELISA), 24?h after the last exposure. The pattern of MCP-1 production by bronchial epithelial cells was different between the two models. MCP-1 release was increased after 3 days of exposure in the CSE model, but was inhibited using the smoking chamber model. Production of IL-10 by NRBE was reduced after 3 days in both models. Finally, no difference was observed in the production of VEGF between the two models. CSE and the smoking chamber differently modulate bronchial epithelial cell mediator production, demonstrating that the model of cigarette smoke exposure used can influence the data obtained.     

Perinatal exposure to aged and diluted sidestream cigarette smoke produces airway hyperresponsiveness in older rats

Exposing rats to aged and diluted sidestream cigarette smoke (ADSS) throughout in utero and postnatal life results in airway hyperresponsiveness and an increase in pulmonary neuroendocrine cells (PNECs) and neuroepithelial bodies (NEBs) in 7- to 10-week-old rats. Since human epidemiologic studies suggest that perinatal exposure to environmental tobacco smoke (ETS) may be detrimental to the lung function of older children, this study was designed to determine if perinatal exposure alone results in airway hyperresponsiveness and increased PNECs/NEBs later in life in rats. Pregnant Sprague-Dawley rats were exposed to filtered air (FA, n = 7) or ADSS (1 mg/m3 total suspended particulates, n = 7) for 4 to 6 h/day starting on Day 3 of gestation. Their pups continued to receive the same exposure regimen postnatally until 21 days of age. Thereafter all pups were exposed to FA until about 8 weeks of age. The airway responsiveness of one female pup from each litter was then assessed using an isolated perfused lung system whereby increasing doses of methacholine (-9.25 to -7.50 log mol) were administered into the pulmonary artery and lung resistance (Rl), dynamic compliance (Cdyn), and pulmonary pressure (Ppa) were measured. The number of PNECs/NEBs and mast cells per millimeter basal lamina were determined using immunocytochemical and histological staining and morphometric analysis. Statistics were performed using an unpaired Student's t test and repeated measures analysis of variance. Perinatal ADSS exposure enhanced methacholine-induced changes in Rl (p = 0.02), Cdyn (p = 0.004), and Ppa (p = 0.007). At the highest dose of methacholine, Rl in the ADSS-exposed lungs was threefold that in FA-exposed lungs. Although total PNEC number increased approximately twofold in the ADSS-exposed animals, this change was not found to be statistically significant. Mast cell number also was not different between groups. These data suggest that exposure to ADSS during the perinatal period followed by 5 weeks exposure to FA induces airway hyperresponsiveness in the absence of a significant change in PNECs, NEBs, or mast cells.     

Effects of prenatal exposure to cigarette smoke on offspring tumor susceptibility and associated immune mechanisms.

Epidemiologic evidence suggests that prenatal exposure to intact (unfractionated) cigarette smoke (CS) increases the incidence of cancer in the offspring. A toxicology study was carried out to examine the effects and underlying mechanisms of prenatal exposure to mainstream cigarette smoke (MCS) on offspring resistance to tumor challenge and surveillance mechanisms critical for the recognition and destruction of tumors. Pregnant B6C3F1 mice were exposed by inhalation to MCS for 5 days/week (4 h/day from gestational day 4 to parturition). Smoke-induced effects on offspring-host resistance to transplanted tumor cells; natural killer (NK) cell and cytotoxic T-lymphocyte (CTL) activity; cytokine levels; lymphoid organ immune cell subpopulations; and histology-were examined in 5-, 10- and 20-week-old male and female offspring. At a concentration of smoke roughly equivalent to smoking <1 pack of cigarettes/day, prenatally exposed male offspring challenged at 5 week of age with EL4 lymphoma cells demonstrated a greater than two-fold increase in tumor incidence (relative to age-/gender-matched air-exposed offspring); tumors in prenatally smoke-exposed pups also grew significantly faster. Cytotoxic T-lymphocyte activity in the smoke-exposed 5- and 10-week-old male pups was significantly less than that of the age- and gender-matched controls. No effects of prenatal CS exposure were observed on offspring NK activity, cytokine levels, lymphoid organ histology, or immune cell subpopulations. Results demonstrated that exposure of pregnant mice to a relevant dose of MCS decreased offspring resistance against transplanted tumor cells and persistently reduced CTL activity in prenatally exposed pups. This study provides biological plausibility for the epidemiologic data indicating that children of mothers who smoke during pregnancy have a greater risk of developing cancer in later life.     

Brief exposure to cigarette smoke impairs airway epithelial cell innate anti-viral defence

BackgroundHuman rhinovirus (hRV) infections commonly cause acute upper respiratory infections and asthma exacerbations. Environmental cigarette smoke exposure is associated with a significant increase in the risk for these infections in children.ObjectiveTo determine the impact of short-term exposure to cigarette smoke on innate immune responses of airway epithelial cells infected with hRV.MethodsA human bronchial epithelial cell line (HBEC-3KT) was exposed to cigarette smoke extract (CSE) for 30 min and subsequently infected with hRV serotype 1B. Viral-induced cytokine release was measured with AlphaLISA and viral replication quantified by shed viral titer and intracellular viral copy number 24 h post-infection.ResultsCSE induced a concentration-dependent decrease in CXCL10 (p < 0.001) and IFN-β (p < 0.001), with a 79% reduction at the highest dose with an associated 3-fold increase in shed virus. These effects were maintained when infection was delayed up to 24 h post CSE exposure. Exogenous IFN-β treatment at t = 0 after infection blunts the effects of CSE on viral replication (p < 0.05).ConclusionA single exposure of 30 min to cigarette smoke has a lasting impact on epithelial innate defence providing a plausible mechanism for the increase in respiratory infections seen in children exposed to second-hand tobacco smoke.     

Brief exposure to cigarette smoke impairs airway epithelial cell innate anti-viral defence

BackgroundHuman rhinovirus (hRV) infections commonly cause acute upper respiratory infections and asthma exacerbations. Environmental cigarette smoke exposure is associated with a significant increase in the risk for these infections in children.ObjectiveTo determine the impact of short-term exposure to cigarette smoke on innate immune responses of airway epithelial cells infected with hRV.MethodsA human bronchial epithelial cell line (HBEC-3KT) was exposed to cigarette smoke extract (CSE) for 30 min and subsequently infected with hRV serotype 1B. Viral-induced cytokine release was measured with AlphaLISA and viral replication quantified by shed viral titer and intracellular viral copy number 24 h post-infection.ResultsCSE induced a concentration-dependent decrease in CXCL10 (p < 0.001) and IFN-β (p < 0.001), with a 79% reduction at the highest dose with an associated 3-fold increase in shed virus. These effects were maintained when infection was delayed up to 24 h post CSE exposure. Exogenous IFN-β treatment at t = 0 after infection blunts the effects of CSE on viral replication (p < 0.05).ConclusionA single exposure of 30 min to cigarette smoke has a lasting impact on epithelial innate defence providing a plausible mechanism for the increase in respiratory infections seen in children exposed to second-hand tobacco smoke.     

Mainstream and sidestream cigarette smoke inhibit growth and angiogenesis in the day 5 chick chorioallantoic membrane.

The purpose of this study was to test the hypothesis that components in mainstream (MS) and sidestream (SS) cigarette smoke inhibit growth and angiogenesis using the chick chorioallantoic membrane (CAM). Varying doses of whole or gas-phase MS and SS smoke solutions were placed on day 5 CAMs, and their effects on angiogenesis were evaluated on day 6. All parameters evaluated (CAM area, major blood vessel area, major blood vessel diameter, blood vessel pattern formation, and capillary plexus formation) were inhibited to different degrees in a dose-dependent manner by both MS and SS smoke treatment. Inhibition of growth and vessel development was correlated with inhibition of cell proliferation. Inhibition of capillary plexus formation was caused by failure of mesodermal blood vessels to migrate to the ectoderm. SS smoke solution was more inhibitory than MS smoke solution in all assays, except for capillary plexus formation. In all assays, the toxicants in SS smoke partitioned mainly with the gas phase, whereas those in MS smoke were deduced to be mainly in the particulate phase in the proliferation-dependent assays (CAM area, blood vessel area, blood vessel diameter) and in both the gas and particulate phase in the pattern formation and plexus formation assays. Some of the inhibitory doses of MS and SS smoke solutions had nicotine concentrations within the range found in human smokers. Taken together, these data demonstrate that exposure to complex mixtures of chemicals in MS and SS cigarette smoke adversely affect growth, vessel development, vessel migration, and cell proliferation.     

Chronic inhalation exposure to mainstream cigarette smoke increases lung and nasal tumor incidence in rats.

An animal model of lung carcinogenicity induced by chronic inhalation of mainstream cigarette smoke would be useful for research on carcinogenic mechanisms, smoke composition-response relationships, co-carcinogenicity, and chemoprevention. A study was conducted to determine if chronic whole-body exposures of rats would significantly increase lung tumor incidence. Male and female F344 rats (n = 81 to 178/gender) were exposed whole-body 6 h/day, 5 days/week for up to 30 months to smoke from 1R3 research cigarettes diluted to 100 (LS) or 250 (HS) mg total particulate matter/m(3), or sham-exposed to clean air (C). Gross respiratory tract lesions and standard lung and nasal sections were evaluated by light microscopy. A slight reduction of survival suggested that the HS level was at the maximum tolerated dose as commonly defined. Cigarette smoke exposure significantly increased the incidences of non-neoplastic and neoplastic proliferative lung lesions in females, while nonsignificant increases were observed in males. The combined incidence of bronchioloalveolar adenomas and carcinomas in females were: HS = 14%; LS = 6%; and C = 0%. These incidences represented minima because only standard lung sections and gross lesions were evaluated. Mutations in codon 12 of the K-ras gene occurred in 4 of 23 (17%) tumors. Three mutations were G to A transitions and one was a G to T transversion. The incidence of neoplasia of the nasal cavity was significantly increased at the HS, but not the LS level in both males and females (HS = 6%, LS = 0.3%, C = 0.4% for combined genders). These results demonstrate that chronic whole-body exposure of rats to cigarette smoke can induce lung cancer.     

Carcinogenic activity of cigarette smoke gas phase and its modulation by beta-carotene and N-acetylcysteine.

Male strain A/J mice were exposed for six hours a day, five days a week for six months to either full tobacco smoke or to tobacco smoke drawn through a HEPA filter that removed more than 99% of particulate matter. After another four months in air, the animals were sacrificed and lung tumors were counted for calculation of multiplicities and incidences. Analysis of the chamber atmospheres showed that in the filtered smoke the concentrations of polycyclic aromatic hydrocarbons and tobacco smoke specific nitrosamines were reduced to from below 18% to even nondetectable levels of the original values measured in the unfiltered smoke. Aldehydes and other volatile organic compounds such as 1,3-butadiene, benzene, or acrolein were reduced to about 50 to 90% of the concentrations found in unfiltered smoke. Some potentially carcinogenic metals reached levels in filtered smoke ranging from 77% to less than 1% found in full smoke. The mice exposed to the filtered smoke atmosphere had practically identical lung tumor multiplicities and incidence as had the animals exposed to full smoke, significantly higher than in air exposed controls. Diets containing 0.5% beta-carotene or 0.4% N-acetylcysteine afforded some chemoprevention. It was tentatively concluded that 1,3-butadiene might be an important contributor to lung tumorigenesis in this mouse model of tobacco smoke carcinogenesis.     

Temporal structure/function variation in cultured differentiated human nasal epithelium associated with acute single exposure to tobacco smoke or E-cigarette vapor

Objective: Mucociliary clearance sustains a baseline functionality and an “on demand” capability to upregulate clearance upon irritant exposure involving mucus hypersecretion and accelerated ciliary beat frequency (CBF) modulated by nitric oxide (NO). This study characterized these elements as well as cellular and exogenous NO concentrations subsequent to a single exposure to tobacco smoke (TS) or e-cigarette vapor (EV) on cultured human airway epithelium.

Materials and methods: Air–liquid interface (ALI) airway epithelial cultures per nonsmoking human subjects were subjected to single TS or EV exposures. Measures of ciliary function and secretion were performed and cellular and exogenous NO concentrations under control and experimental conditions were assessed.

Results: Both TS and EV exposures resulted similar patterns of decline in CBF within 1?min of the completion of exposure followed by a gradual return often exceeding baseline within 1?h. Post-exposure examination of exposed cultures suggested morphologic differences in secretory function relative to controls. The relative NO concentrations of TS and EV chamber air were sharply different with EV NO being only slightly elevated relative to cellular NO production.

Discussion and conclusions: Epithelial remodeling and mucociliary dysfunction have been clearly associated with TS exposure. However, information contrasting epithelial structure/function following a single acute TS or EV exposure is limited. This study demonstrates a similar pattern of epithelial response to acute TS or EV exposure. Inasmuch as NO may contribute to an inflammatory milieu and generation of toxic metabolites, it is plausible that recurrent exposures over time may be contributory to chronic pathologies.     

In utero and lactation exposure of rats to 1R4F reference cigarette mainstream smoke: effect on prenatal and postnatal development.

Childhood cognitive and behavioral deficits have been reported in children born to mothers who smoked during pregnancy (Institute of Medicine, 2001). To investigate these potential responses in an animal model, reproductive and neurotoxicity evaluations based on the U.S. FDA guidelines were used to examine the offspring of male and female Sprague-Dawley rats exposed 2 h/day, 7 days/week by nose-only inhalation to whole mainstream smoke total particulate matter (TPM). Concentrations of 150, 300, or 600 mg/m(3) were used (males: 4 weeks prior to and during mating; and females: 2 weeks prior to mating, during mating, and through weaning at postnatal day 21). Sham air controls receiving filtered air and cage controls were also maintained. F(1) rats were weighed, identified by gender, examined for clinical signs of toxicity, and evaluated for neurobehavioral effects through postnatal day 65. Parental exposure was evidenced by smoke concentration-related increases in blood carboxyhemoglobin, nicotine, and cotinine and by characteristic cigarette smoke-related rodent respiratory tract histopathology. Also, nicotine and cotinine were found in F(1) blood through the lactation period. Maternal toxicity occurred at concentrations of 300 and 600 mg TPM/m(3), where total body weight gain during gestation was significantly (p < or = 0.05) decreased compared to sham controls. While smoke concentration-related decreases in F(1) birth weight and growth were evident (600 mg TPM/m(3), significantly different from sham at all time points), no adverse effects on developmental landmarks, including age at vaginal patency or preputial separation, motor activity, acoustic startle response or learning, and memory, were observed in the F(1) generation. This study confirmed that maternal exposure to high levels of mainstream cigarette smoke during gestation and lactation reduces birth weight and retards growth in the rat neonate; however, the developmental and neurobehavioral testing methodologies employed did not appear to be sensitive for an evaluation of neonatal behavioral effects following parental smoke exposure.     

Toxicological evaluation of an electrically heated cigarette. Part 3: Genotoxicity and cytotoxicity of mainstream smoke

The in vitro toxicity of cigarette mainstream smoke from an electrically heated cigarette (EHC) with controlled combustion was compared with that of the standard University of Kentucky Reference Cigarette 1R4F.In the Salmonella reverse mutation assay, strains TA98, TA100, TA102, TA1535 and TA1537 were used in the absence and presence of a metabolic promutagen activation system (S9) to determine the mutagenic potential of the total particulate matter (TPM), which was collected on a glass-fiber filter. In the neutral red uptake assay, mouse embryo BALB/c 3T3 cells were used to determine the cytotoxic potential of TPM as well as of the water-solubles in the gas/vapor phase trapped in phosphate-buffered saline.The TPM from the electrically heated cigarette was up to 90% lower in mutagenicity than that of the 1R4F calculated on an equal TPM basis. This reduction in mutagenicity is consistent with the significantly lower concentration of nearly all constituents analyzed in EHC smoke. With regard to cytotoxicity when calculated on an equal TPM basis, TPM from the electrically heated cigarette was 40% less active relative to the 1R4F. When calculated on a per cigarette basis, the cytotoxicity of both the TPM fraction and the water-solubles in the gas/vapor phase of smoke from the EHC was ca. 80% lower relative to the 1R4F.     

Correlative ultrastructural investigations of airway epithelium following experimental exposure to defined air pollutants and lifestyle exposure to tobacco smoke

Abstract

Context: Investigations of cell/molecular level effects of in vivo exposure of airway mucosa of experimental animals to common irritant gases have demonstrated structural and physiological changes reflective of breaches in epithelial barrier function, presence of inflammatory cell infiltrate and compromised ciliary function. These experimental animal studies provided useful perspectives of plausible, but more subtle pathologic outcomes having relevance to lifestyle exposure to gaseous environmental irritants including tobacco smoke.

Methods: Freeze-fracture technology was applied to ultrastructural examination of large airway epithelium, with appropriate controls, from guinea pigs exposed to ozone and of nasal mucosa of human subjects exposed to ozone or sulfur dioxide, and nasal mucosa of active smokers.

Results: We documented substantive membrane structural changes to tight junctional complexes and cilia as well as an infiltrate of neutrophils into the surface mucosal layer in exposed animals. These patterns also were evident but not as pervasive among human subjects acutely exposed experimentally to irritant gases and those chronically exposed by their lifestyle to tobacco smoke.

Discussion: Our intent was to characterize respiratory tract mucosal membrane disorganization associated with high level acute irritant exposures in an experimental animal model and to evaluate evidence of similar but perhaps more subtle pathologic change associated with lower level experimental or lifestyle exposures. Our studies demonstrate continuity, albeit subtle, of pathologic change from high dosage experimental animal exposure to low dosage human exposures.

Conclusions: This study represents the first report of ultrastructural airway epithelial membrane anomalies associated with lifestyle exposure to tobacco smoke irritants.     

Identification of pyridine compounds in cigarette smoke solution that inhibit growth of the chick chorioallantoic membrane.

Based on prior work, we hypothesized that cigarette smoke contains chemicals that can inhibit growth of the chick chorioallantoic membrane (CAM). In this study, gas chromatography and mass spectrometry were used to identify 12 pyridine derivatives in the inhibitory fractions of smoke eluted from solid phase extraction cartridges. These pyridine derivatives were further studied individually in dose response experiments to determine their effects on CAM growth. A correlation was observed between the functional group substitutions on pyridine and the relative toxicity of each pyridine derivative. In the CAM growth assay, pyridine derivatives with single methyl or single ethyl substitutions had lowest observed adverse effect levels (LOAELs) of 5 x 10(-9) and 5 x 10(-12) M, respectively. Other pyridine derivatives and pyridine itself had LOAELs in the micromolar range. One of the most inhibitory derivatives, 3-ethylpyridine, was studied further and inhibited cell proliferation, as measured by BrdU incorporation. Since 3-ethylpyridine inhibited growth at picomolar doses and is added to consumer products including cosmetics, food, drinks, and tobacco, it will be important to perform further toxicological testing to determine its effect on human health.     

In utero exposure to 1R4F reference cigarette smoke: evaluation of developmental toxicity.

The potential developmental effects of 1R4F reference cigarette smoke were examined using Sprague-Dawley rats exposed for 2 h/day, 7 days/week, by nose-only inhalation at target mainstream smoke concentrations of 150, 300, and 600 mg/m3 total particulate matter (TPM). Males were exposed 4 weeks prior to and during mating, with females exposed 2 weeks prior to mating and during mating, and through gestation day (GD) 20. Sham controls received filtered air to simulate nose-only exposure, while cage controls were maintained untreated. Smoke exposure was confirmed through biomarker evaluation (parental: carboxyhemoglobin, nicotine, and cotinine; fetal: nicotine and cotinine). Characteristic cigarette smoke-related histopathologic changes including nasal epithelial hyperplasia and squamous metaplasia and pigmented macrophages in the lung were observed in all exposed parental groups. Maternal toxicity during gestation was indicated at smoke concentrations of 300 and 600 mg TPM/m3, where corrected total body weight gain was significantly (p 相似文献   

Pulmonary response of mice to a sequential exposure of side-stream cigarette smoke and multi-walled carbon nanotubes

Abstract

Due to their unique properties, nano-sized carbon materials are predicted to have numerous applications in industry, but significant evidence exists to suggest their potential to cause toxicity. To determine if pre-exposure to side-stream cigarette smoke (SSCS) influences their toxicity, we examined the pulmonary response of smoke-exposed mice to multi-walled carbon nanotubes (MWCNT). Female A/J mice were exposed to SSCS in a whole body exposure chamber at approximately 40?mg/m³ for 4 weeks (6?h/d, 5?d/wk) and challenged with a single dose of MWCNT (40?µg) by the pharyngeal aspiration technique. A total of four groups were compared: air/phosphate buffered saline (PBS)-control, SSCS/PBS, air/MWCNT, and SSCS/MWCNT. At days 1 and 3 post-MWCNT treatment, lung tissues and bronchoalveolar lavage fluid (BALF) were collected and analyzed. In comparison with controls, significantly higher levels of total BAL cells were obtained from mice exposed to SSCS and MWCNT alone or combination. Influx of polymorphonuclear leukocytes (PMN) into BALF greatly increased in MWCNT alone and SSCS/MWCNT groups at both days 1 and 3 compared with controls. However, pre-exposure to SSCS significantly suppressed PMN response to MWCNT on day 1 but not day 3. Total BALF protein, lactate dehydrogenase, and mucin were significantly elevated in MWCNT and SSCS/MWCNT groups but not in the SSCS group, except mucin at day 3, when compared with controls. These results demonstrate that MWCNT markedly increases pulmonary toxicity in mice and SSCS pre-exposure plays a minor role in modulating MWCNT-induced lung toxicity at the concentrations and time points selected in the present study.     

Comparative effects between electronic and cigarette smoke in human keratinocytes and epithelial lung cells

Information about the harmful effects of vaping is sparse and inconsistent, therefore, since the use of electronic cigarettes (e-CIGs) has become increasingly popular as a tool to limit tobacco smoking, it is urgent to establish the toxicity of the commercial e-CIGs.Skin (HaCaT) and lung (A549) cells, the main targets of cigarette smoke (CS), were exposed to e-CIG vapor and CS using an in vitro system. The cytotoxic effect of the exposure was analyzed in both cell types by ultrastructural morphology, Trypan Blue exclusion test and LDH assay. In addition, pro-inflammatory cytokines were measured by the Bio-Plex assay.The cytotoxic components of e-CIG were restrained to the flavoring compound and, to a lesser extent, to nicotine although their effects were less harmful to that of CS. Humectants alone exhibited no cytotoxicity but induced the release of cytokines and pro-inflammatory mediators.Based on our results, we can state that exposure to e-CIG vapors results in far less toxic than exposure to CS. In fact, besides the deleterious effect of flavor and nicotine, even the humectants alone are able to evocate cytokines release. This study will hopefully promote the development of safer e-CIGs to help people quit smoking.     

Acute exposure to waterpipe tobacco smoke induces changes in the oxidative and inflammatory markers in mouse lung

Context: Tobacco smoking represents a global public health threat, claiming approximately 5 million lives a year. Waterpipe tobacco use has become popular particularly among youth in the past decade, buttressed by the perception that the waterpipe “filters” the smoke, rendering it less harmful than cigarette smoke.

Objective: In this study, we examined the acute exposure of waterpipe smoking on lung inflammation and oxidative stress in mice, and compared that to cigarette smoking.

Materials and methods: Mice were divided into three groups; fresh air control, cigarette and waterpipe. Animals were exposed to fresh air, cigarette, or waterpipe smoke using whole body exposure system one hour daily for 7 days.

Results: Both cigarette and waterpipe smoke exposure resulted in elevation of total white blood cell count, as well as absolute count of neutrophils, macrophages, and lymphocytes (P < 0.01). Both exposures also elevated proinflammatory markers such as TNF-α and IL-6 in BALF (P < 0.05), and oxidative stress markers including GPx activity in lungs (P < 0.05). Moreover, waterpipe smoke increased catalase activity in the lung (P < 0.05). However, none of the treatments altered IL-10 levels.

Discussion and conclusion: Results of cigarette smoking confirmed previous finding. Waterpipe results indicate that, similar to cigarettes, exposure to waterpipe tobacco smoke is harmful to the lungs.     

Evidence for carbon monoxide as the major factor contributing to lower fetal weights in rats exposed to cigarette smoke.

One of the major effects of cigarette smoking during pregnancy is bearing a child with lower birth weight. It has previously been demonstrated under experimental conditions in rats that exposure to reference cigarette smoke results in reduced birth weight (E. L. Carmines et al., 2003, Toxicol. Sci. 75, 134-147; C. L. Gaworski et al., 2004, Toxicol. Sci. 79, 157-169). The role of various smoke constituents on lower birth weight was evaluated by exposing time-pregnant Sprague-Dawley rats at the concentrations found in cigarette smoke. The rats were exposed for 2 h/day 7 days/week by nose-only inhalation. The target concentrations were designed to produce the same plasma levels of biomarkers as exposure to 2R4F reference cigarette smoke at a concentration of 600 mg/m(3) total particulate matter. The smoke constituents evaluated included carbon monoxide (CO), nicotine, and a mixture of aldehydes (acrolein, acetaldehyde, and formaldehyde). The smoke constituents were tested individually as well as in mixtures to evaluate potential interactions. Exposure to cigarette smoke during gestation produced a reduction in both maternal body weight gain and fetal weights. Exposure to nicotine reduced maternal body weight gain but had no effect on fetal weight. Exposure to CO had no effect on maternal body weight gain but reduced fetal weight to a degree comparable to cigarette smoke. Exposure to a mixture of aldehydes (acrolein, acetaldehyde, and formaldehyde) had no effect on either maternal body weight gain or fetal weight. Exposure to mixtures of nicotine and CO or nicotine, CO, and aldehydes did not demonstrate any interactions. The results of this study suggest that the observed reduction in fetal weight after exposure to cigarette smoke in rats is due to CO toxicity and not nicotine toxicity.     

Differential gene expression in human peripheral blood mononuclear cells induced by cigarette smoke and its constituents.

In current molecular epidemiology studies, a wide range of methods are used to monitor early biological effects after exposure to xenobiotic agents. Gene expression profiling is considered a promising tool that may provide more sensitive, mechanism-based biomarkers. As a first step toward obtaining information on the applicability of gene expression profiles as a biomarker for early biological effects of carcinogen exposure, we conducted in vitro studies on human peripheral blood mononuclear cells (PBMC). We used cigarette smoke condensate (CSC) and a selection of its genotoxic constituents as model agents, applying cDNA microarray technology to investigate modulated gene expression. In independent experiments using cells from several donors, quiescent PBMC were exposed for 18 h, followed by gene expression analyses on a microarray containing 600 toxicologically relevant genes. The search for candidate biomarker genes was binomial: first we looked for genes responding similarly to all agents; second, for agent-specific genes. Many genes were significantly deregulated by all compounds, but as the direction of deregulation frequently differed per agent, they are not useful as generic biomarkers. Cigarette smoke condensate modulated the expression of many more genes than any of its constituents, with the largest effect in SERPINB2. The affected genes are involved in immune or stress responses, but surprisingly no genes involved in DNA damage response were modulated, and only a few in DNA repair. In conclusion, several genes have been identified as potential biomarkers for population studies on early biological effects caused by cigarette smoke exposure, but no genes were identified that represent a generic biomarker.