Threshold of biologic responses of the small airway epithelium to low levels of tobacco smoke

Serial Sampling of the Small Airway Epithelium to Identify Persistent Smoking-dysregulated Genes

Rationale: The small airway epithelium (beyond the sixth generation), the initiation site of smoking-induced airway disorders, is highly sensitive to the stress of smoking. Because of variations over time in smoking habits, the small airway epithelium transcriptome is dynamic, fluctuating not only among smokers but also within each smoker. Objectives: To perform accurate assessment of the smoking-related dysregulation of the human small airway epithelium despite the variation of smoking within the same individual and of the effects of smoking cessation on the dysregulated transcriptome. Methods: We conducted serial sampling of the same smokers and nonsmoker control subjects over time to identify persistent smoking dysregulation of the biology of the small airway epithelium over 1 year. We conducted serial sampling of smokers who quit smoking, before and after smoking cessation, to assess the effect of smoking cessation on the smoking-dysregulated genes. Measurements and Main Results: Repeated measures ANOVA of the small airway epithelium transcriptome sampled four times in the same individuals over 1 year enabled the identification of 475 persistent smoking-dysregulated genes. Most genes were normalized after 12 months of smoking cessation; however, 53 (11%) genes, including CYP1B1, PIR, ME1, and TRIM16, remained persistently abnormally expressed. Dysregulated pathways enriched with the nonreversible genes included xenobiotic metabolism signaling, bupropion degradation, and nicotine degradation. Conclusions: Analysis of repetitive sampling of the same individuals identified persistent smoking-induced dysregulation of the small airway epithelium transcriptome and the effect of smoking cessation. These results help identify targets for the development of therapies that can be applicable to smoking-related airway diseases.

Defining the in vivo mechanism of air pollutant toxicity using murine stress response biomarkers

Air pollution can cause a wide range of serious human diseases. For the informed instigation of interventions which prevent these outcomes there is an urgent need to develop robust in vivo biomarkers which provide insights into mechanisms of toxicity and relate pollutants to specific adverse outcomes. We exemplify for a first time the application of in vivo stress response reporters in establishing mechanisms of air pollution toxicity and the application of this knowledge in epidemiological studies. We first demonstrated the utility of reporter mice to understand toxicity mechanisms of air pollutants using diesel exhaust particles compounds. We observed that nitro-PAHs induced Hmox1 and CYP1a1 reporters in a time- and dose-dependent, cell- and tissue-specific manner. Using in vivo genetic and pharmacological approaches we confirmed that the NRF2 pathway mediated this Hmox1-reporter induction stress reporter activity. We then correlated the activation of stress-reporter models (oxidative stress/inflammation, DNA damage and Ah receptor -AhR- activity) with responses in primary human nasal cells exposed to chemicals present in particulate matter (PM; PM2.5-SRM2975, PM10-SRM1648b) or fresh roadside PM10. To exemplify their use in clinical studies, Pneumococcal adhesion was assessed in exposed primary human nasal epithelial cells (HPNEpC). The combined use of HPNEpC and in vivo reporters demonstrated that London roadside PM10 particles induced pneumococcal infection in HPNEpC mediated by oxidative stress responses. The combined use of in vivo reporter models with human data thus provides a robust approach to define the relationship between air pollutant exposure and health risks. Moreover, these models can be used in epidemiological studies to hazard ranking environmental pollutants by considering the complexity of mechanisms of toxicity. These data will facilitate the relationship between toxic potential and the level of pollutant exposure in populations to be established and potentially extremely valuable tools for intervention studies for disease prevention.

Particle Exposure Hazards of Visiting Outdoor Smoking Areas for Patients with Asthma or COPD Even in EU Countries with Comprehensive Smokefree Laws

Smokefree laws are intended to protect against second-hand smoke (SHS) in outdoor areas. We examined if exposure to PM2.5 particles in outdoor smoking areas changed breathing rates in 60 patients with asthma (n = 30) or with COPD (n = 30), in an open, non-randomised, interventional study model in Czechia, Ireland and Spain. The patients wore a PM2.5 particle monitor (AirSpeck) and a breath monitor (RESpeck) for 24 h to determine changes in breathing rates (Br) at rest and during a visit to an outside smoking area. Spirometry and breath CO were measured before and the day after visiting an outdoor smoking area. The PM2.5 levels at the 60 venues were highly variable, ranging from ≥2000 µg/m3 (in 4 premises) to ≤10 µg/m3 (in 3 premises, which had only a single wall in the structure). At 39 venues, the mean PM 2.5 levels were ≥25 µg/m3. The breathing rate changed significantly in 57 of the 60 patients, resulting in an increase in some patients and a decrease in others. Comprehensive smokefree laws were ineffective in protecting asthma and COPD patients from exposure to high levels of SHS in outside areas of pubs and terraces, which should be avoided by these patients. These findings also support the extension of smokefree laws to outside areas.

Early transcriptional responses of bronchial epithelial cells to whole cigarette smoke mirror those of in-vivo exposed human bronchial mucosa

BACKGROUND

Despite the well-known detrimental effects of cigarette smoke (CS), little is known about the complex gene expression dynamics in the early stages after exposure. This study aims to investigate early transcriptomic responses following CS exposure of airway epithelial cells in culture and compare these to those found in human CS exposure studies.

METHODS

Primary bronchial epithelial cells (PBEC) were differentiated at the air-liquid interface (ALI) and exposed to whole CS. Bulk RNA-sequencing was performed at 1 h, 4 h, and 24 h hereafter, followed by differential gene expression analysis. Results were additionally compared to data retrieved from human CS studies.

RESULTS

ALI-PBEC gene expression in response to CS was most significantly changed at 4 h after exposure. Early transcriptomic changes (1 h, 4 h post CS exposure) were related to oxidative stress, xenobiotic metabolism, higher expression of immediate early genes and pro-inflammatory pathways (i.e., Nrf2, AP-1, AhR). At 24 h, ferroptosis-associated genes were significantly increased, whereas PRKN, involved in removing dysfunctional mitochondria, was downregulated. Importantly, the transcriptome dynamics of the current study mirrored in-vivo human studies of acute CS exposure, chronic smokers, and inversely mirrored smoking cessation.

CONCLUSION

These findings show that early after CS exposure xenobiotic metabolism and pro-inflammatory pathways were activated, followed by activation of the ferroptosis-related cell death pathway. Moreover, significant overlap between these transcriptomic responses in the in-vitro model and human in-vivo studies was found, with an early response of ciliated cells. These results provide validation for the use of ALI-PBEC cultures to study the human lung epithelial response to inhaled toxicants.

Colonization by Streptococcus pneumoniae among children in Porto Velho, Rondônia, Western Brazilian Amazon

Streptococcus pneumoniae is one of the primary pathogens that are associated with acute respiratory infections (ARI) that cause high rates of morbidity and mortality among children under five years of age in developed and developing countries. This study aimed to determine the prevalence of nasopharyngeal colonization, the antimicrobial resistance profile, and the capacity for biofilm formation by S. pneumoniae isolated from children aged 0-6 years with ARI throughout the Porto Velho-RO. A total of 660 swabs were collected from children with ARI. Molecular and biochemical tests were performed to characterize the isolates. The disk-difusion method and the E-test were used for antimicrobial sensitivity testing (TSA). Biofilm formation capacity was assessed using microtiter plate assays, and serotype detection was acheived using polymerase chain reaction (PCR) analyses. The colonization rate for S. pneumoniae was 8.9% (59/660) and exhibited a high prevalence in children under 23 months of age 64.4% (38/59). The observed serotypes were 9V and 19F with frequencies of 1.7% (1/59) and 13.6% (8/59), respectively. The antimicrobial susceptibility test revealed 100% (59/59) sensitivity to vancomycin. In contrast, trimethoprim and oxacillin exhibited high resistance rates of 76.3% (45/59) and 52.5% (31/59), respectively. Of the biofilm-forming isolates, 54.8% (23/42) possessed resistance to some antimicrobials. In this study, S. pneumoniae showed high rates of antimicrobial resistance and the ability to form biofilms, as these are factors that favor bacterial persistence and can cause serious damage to the host.

COPD lung studies of Nrf2 expression and the effects of Nrf2 activators

BACKGROUND

Nrf2 regulates cellular antioxidant defence in lung cells, including epithelial cells and alveolar macrophages (AM). The Nrf2/Keap-1 pathway can be modulated by activators with different modes of action; electrophilic compounds and protein-protein interaction (PPI) inhibitors. We assessed Nrf2 and Keap-1 protein and gene levels in COPD compared to controls and the effect of Nrf2 activators on COPD AM.

METHODS

Lung resected tissue from non-smokers, smokers and COPD patients were analysed for epithelial and AM expression of Nrf2 and Keap-1 by imunoshistochemistry and by qPCR in isolated AM. AM were cultured with Nrf2 activators CDDO, C4X_6665, GSK7, MMF and Sulforaphane. Expression of Nrf2 target genes NQO1, HMOX1 SOD1 and TXNRD1 and NQO1 activity were assessed.

RESULTS

Nrf2 and Keap-1 expression was not altered in the epithelium or AM of COPD patients compared to controls. NQO1 activity was downregulated, while NQO1, HMOX1, SOD1 and TXNRD1 gene expression increased in COPD patients. All Nrf2 activators increased NQO1 activity, and NQO1, HMOX1, SOD1 and TXNRD1 expression in AMs from both COPD and smokers. The potency of C4X_6665 on NQO1 activity and regulation of Nrf2 target gene expression was higher than other compounds.

CONCLUSION

There is evidence of dysregulation of the Nrf2 signalling pathway in AM from COPD patients. The higher potency of the novel PPI Nrf2 compound C4X_6665 for inducing antioxidant activity and gene expression compared to electrophilic and other PPI Nrf2 activators highlights the therapeutic potential of this compound to address Nrf2 pathway dysregulation in COPD AM.

Home Smoking Bans and Urinary NNAL Levels to Measure Tobacco Smoke Exposure in Chinese American Household Pairs

Home smoking bans can reduce tobacco smoke exposure, but little is known about the impact for Chinese American household pairs. In this study of 202 household pairs with low acculturation, 53.9% reported a home smoking ban, 31.7% had inconsistent reports, and 14.4% reported no ban. With decreasing home smoking ban enforcement, more nonsmokers had tobacco smoke exposure (66.1%–86.2%) as measured by the tobacco-specific nitrosamine biomarker urine NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol). Despite reported bans, about one-quarter of nonsmokers still reported tobacco smoke exposure at home (23.6%–30%) within the past 2 months and three-quarters reported outdoor exposure. In adjusted regression analyses of geometric mean NNAL ratios, nonsmokers in households with no ban had over two times higher levels than nonsmokers in households with a ban: adjusted log NNAL ratio = 2.70 (95% CI 1.21, 6.03). Higher smoker NNAL level and nonsmoker English fluency were also significantly associated with nonsmoker NNAL levels. Nonsmoker levels in households with an inconsistent ban were not significantly different compared to those with a ban. Although home smoking bans were generally associated with lower NNAL levels, tobacco smoke exposure in this immigrant population with low English proficiency was higher than that of the general population. From a health equity standpoint, there is a need for broader implementation and enforcement of comprehensive smoke-free policies.

Up-regulation of ACE2, the SARS-CoV-2 receptor, in asthmatics on maintenance inhaled corticosteroids

BACKGROUND

The first step in SARS-CoV-2 infection is binding of the virus to angiotensin converting enzyme 2 (ACE2) on the airway epithelium. Asthma affects over 300 million people world-wide, many of whom may encounter SARS-CoV-2. Epidemiologic data suggests that asthmatics who get infected may be at increased risk of more severe disease. Our objective was to assess whether maintenance inhaled corticosteroids (ICS), a major treatment for asthma, is associated with airway ACE2 expression in asthmatics.

METHODS

Large airway epithelium (LAE) of asthmatics treated with maintenance ICS (ICS+), asthmatics not treated with ICS (ICS-), and healthy controls (controls) was analyzed for expression of ACE2 and other coronavirus infection-related genes using microarrays.

RESULTS

As a group, there was no difference in LAE ACE2 expression in all asthmatics vs controls. In contrast, subgroup analysis demonstrated that LAE ACE2 expression was higher in asthmatics ICS+ compared to ICS‾ and ACE2 expression was higher in male ICS+ compared to female ICS+ and ICS‾ of either sex. ACE2 expression did not correlate with serum IgE, absolute eosinophil level, or change in FEV1 in response to bronchodilators in either ICS- or ICS+.

CONCLUSION

Airway ACE2 expression is increased in asthmatics on long-term treatment with ICS, an observation that should be taken into consideration when assessing the use of inhaled corticosteroids during the pandemic.

[Smoking cessation in asthmatic patients and its impact]

INTRODUCTION

The prevalence of smoking in asthmatic patients is similar to, or even higher than in the general population.

OBJECTIVES

This systematic review addresses (1) the effects of smoking on asthma, (2) smoking cessation strategies in asthmatic patients, and (3) the consequences of smoking cessation for people with asthma.

RESULTS

Active or passive smoking can promote the development of asthma. The few studies on smoking cessation in asthma confirm the efficacy of validated smoking cessation strategies in these patients (nicotine replacement therapy, varenicline, bupropion, cognitive and behavioural therapies). Smoking cessation in parents with asthmatic children is essential and is based on the same strategies. Electronic cigarettes may be a useful help to quit smoking in some patients. Smoking cessation is beneficial in asthmatic smokers and associated with (1) a reduction of asthma symptoms, acute exacerbations, bronchial hyperresponsiveness, and bronchial inflammation, (2) decreased use of rescue medications and in doses of inhaled corticosteroids, (3) improved asthma control, quality of life, and lung function.

CONCLUSION

In asthmatic patients, it is essential to assess smoking status and health professionals must assist them to quit smoking.

Expression of endocannabinoid system components in human airway epithelial cells: impact of sex and chronic respiratory disease status

Cannabis smoking is the dominant route of delivery, with the airway epithelium functioning as the site of first contact. The endocannabinoid system is responsible for mediating the physiological effects of inhaled phytocannabinoids. The expression of the endocannabinoid system in the airway epithelium and contribution to normal physiological responses remains to be defined. To begin to address this knowledge gap, a curated dataset of 1090 unique human bronchial brushing gene expression profiles was created. The dataset included 616 healthy subjects, 136 subjects with asthma, and 338 subjects with COPD. A 32-gene endocannabinoid signature was analysed across all samples with sex and disease-specific analyses performed. Immunohistochemistry and immunoblots were performed to probe in situ and in vitro protein expression. CB₁, CB₂, and TRPV1 protein signal is detectable in human airway epithelial cells in situ and in vitro, justifying examining the downstream endocannabinoid pathway. Sex status was associated with differential expression of 7 of 32 genes. In contrast, disease status was associated with differential expression of 21 of 32 genes in people with asthma and 26 of 32 genes in people with COPD. We confirm at the protein level that TRPV1, the most differentially expressed candidate in our analyses, was upregulated in airway epithelial cells from people with asthma relative to healthy subjects. Our data demonstrate that the endocannabinoid system is expressed in human airway epithelial cells with expression impacted by disease status and minimally by sex. The data suggest that cannabis consumers may have differential physiological responses in the respiratory mucosa.

Association of Cigarette Smoking, COPD, and Lung Cancer With Expression of SARS-CoV-2 Entry Genes in Human Airway Epithelial Cells

SARS-CoV-2 enters into human airway epithelial cells via membrane fusion or endocytosis, and this process is dependent on ACE2, TMPRSS2, and cathepsin L. In this study, we examined the expression profiles of the three SARS-CoV-2 entry genes in primary human airway epithelial cells isolated from smokers, non-smokers, patients with chronic obstructive pulmonary disease or lung cancer. An exhaustive search of the GEO database was performed to identify eligible data on 1st June 2020. In total, 46 GEO datasets comprising transcriptomic data of 3,053 samples were identified as eligible data for further analysis. All meta-analysis were performed using RStudio. Standardized mean difference was utilized to assess the effect size of a factor on the expression of targeted genes and 95% confidence intervals (CIs) were calculated. This study revealed that (i) cigarette smoking is associated with an increased expression of ACE2 and TMPRSS2 and a decreased expression of cathepsin L; (ii) significant alternations in expression of ACE2, TMPRSS2, and cathepsin L were observed between current smokers and former smokers, but not between former smokers and never smokers; (iii) when compared with healthy controls with identical smoking status, patients with COPD or lung cancer showed negligible changes in expression of ACE2, TMPRSS2, and cathepsin L. Therefore, this study implicates cigarette smoking might contribute to the development of COVID-19 by affecting the expression of SARS-CoV-2 entry genes, while smoking cessation could be effective to reduce the potential risk.

ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19

Smokers and those with COPD have increased airway expression of ACE-2, which is the entry receptor for the COVID-19 virus. This may explain the increased risk of severe COVID-19 in these subpopulations and highlight the importance of smoking cessation. https://bit.ly/3bC29es

ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19) a pandemic [1]. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 displays symptoms ranging from mild to severe (pneumonia) that can lead to death in some individuals [2–4]. As of 18 April 2020, there have been 2 280 945 cases of COVID-19 worldwide and 156 354 deaths [5]. SARS-CoV-2 uses the angiotensin-converting enzyme II (ACE-2) as the cellular entry receptor [6]. While the virus can infect individuals of any age, to date, most of the severe cases have been described in those >55 years of age and with significant comorbidities, such as COPD [7]. Here, we determined whether patients with COPD have increased expression of ACE-2 in bronchial epithelial cells in the lower respiratory tract.

Smokers and those with COPD have increased airway expression of ACE-2, which is the entry receptor for the COVID-19 virus. This may explain the increased risk of severe COVID-19 in these subpopulations and highlight the importance of smoking cessation. https://bit.ly/3bC29es

Exposure to secondhand aerosol of electronic cigarettes in indoor settings in 12 European countries: data from the TackSHS survey

INTRODUCTION

Exposure to secondhand aerosol from e-cigarette (SHA) may pose harmful effects to bystanders. This study aims to investigate the prevalence, duration and determinants of SHA exposure in various indoor settings in 12 European countries.

METHODS

In 2017-2018, we conducted a cross-sectional study, the TackSHS survey, on a representative sample of the population aged ≥15 years in 12 European countries (Bulgaria, England, France, Germany, Greece, Ireland, Italy, Latvia, Poland, Portugal, Romania and Spain). We described the prevalence and duration of exposure to SHA in several indoor settings among 11 604 e-cigarette non-users. Individual-level and country-level characteristics associated with SHA exposure were also explored using multilevel logistic regression analyses.

RESULTS

Overall, 16.0% of e-cigarette non-users were exposed to SHA in any indoor setting at least weekly, ranging from 4.3% in Spain to 29.6% in England. The median duration of SHA exposure among those who were exposed was 43 min/day. 'Other indoor settings' (eg, bar and restaurant) was reported as the place where most of e-cigarette non-users were exposed (8.3%), followed by workplace/educational venues (6.4%), home (5.8%), public transportation (3.5%) and private transportation (2.7%). SHA exposure was more likely to occur in certain groups of non-users: men, younger age groups, those with higher level of education, e-cigarette past users, current smokers, those perceiving SHA harmless and living in countries with a higher e-cigarette use prevalence.

CONCLUSIONS

We found inequalities of SHA exposure across and within European countries. Governments should consider extending their tobacco smoke-free legislation to e-cigarettes to protect bystanders, particularly vulnerable populations such as young people.

TRIAL REGISTRATION NUMBER

NCT02928536.

Biomarkers of Exposure and Effect in the Lungs of Smokers, Nonsmokers, and Electronic Cigarette Users

BACKGROUND

Nicotine-containing electronic cigarette (e-cig) use has become widespread. However, understanding the biological impact of e-cigs compared with smoking on the lung is needed. There are major gaps in knowledge for chronic effects and for an etiology to recent acute lung toxicity leading to death among vapers.

METHODS

We conducted bronchoscopies in a cross-sectional study of 73 subjects (42 never-smokers, 15 e-cig users, and 16 smokers). Using bronchoalveolar lavage and brushings, we examined lung inflammation by cell counts, cytokines, genome-wide gene expression, and DNA methylation.

RESULTS

There were statistically significant differences among never-smokers, e-cig users, and smokers for inflammatory cell counts and cytokines (FDR q < 0.1). The e-cig users had values intermediate between smokers and never-smokers, with levels for most of the biomarkers more similar to never-smokers. For differential gene expression and DNA methylation, e-cig users also more like never-smokers; many of these genes corresponded to smoking-related pathways, including those for xenobiotic metabolism, aryl hydrocarbon receptor signaling, and oxidative stress. Differentially methylated genes were correlated with changes in gene expression, providing evidence for biological effects of the methylation associations.

CONCLUSIONS

These data indicate that e-cigs are associated with less toxicity than cigarettes for smoking-related pathways. What is unknown may be unique effects for e-cigs not measured herein, and a comparison of smokers completely switching to e-cigs compared with former smokers. Clinical trials for smokers switching to e-cigs who undergo serial bronchoscopy and larger cross-sectional studies of former smokers with and without e-cig use, and for e-cigs who relapse back to smoking, are needed.

IMPACT

These data can be used for product regulation and for informing tobacco users considering or using e-cigs. What is unknown may be unique effects for e-cigs not measured herein, and clinical trials with serial bronchoscopy underway can demonstrate a direct relationship for changes in lung biomarkers.

Exposure to secondhand smoke in vehicles among Canadian adolescents: Years after the adoption of smoke-free car laws

Exposure to secondhand smoke (SHS) can result in several adverse health consequences. SHS concentrations in vehicles can significantly exceed levels present in other enclosed spaces. Years after the adoption of smoke-free car laws, this study examined the prevalence of exposure to SHS in vehicles among adolescents. Data were utilized from the 2016-2017 Canadian Student Tobacco, Alcohol and Drugs Survey (n = 48,444). The prevalence of exposure to SHS in cars was estimated by grade level and demographic characteristics. The results showed a gradient by grade level in exposure to SHS with students in upper-grade levels reporting a higher prevalence of SHS in cars. SHS varied by province, with the lowest rate found in British Columbia (15.6%) and the highest in Saskatchewan (36.9%). The provinces with laws that extend protections to older children also had high rates of SHS exposure among students in upper-grade levels. Students exposed to SHS were more likely to engage in risky behaviors, including the use of marijuana, alcohol, cigarettes, and e-cigarettes. Despite laws prohibiting smoking in vehicles carrying children, SHS prevalence remains high. While enforcement of these laws may be challenging, persuasion campaigns highlighting that children are especially vulnerable to the health risks of SHS may be beneficial.

Regulation of interferon stimulated gene expression levels at homeostasis

Interferon stimulated genes (ISGs), a collection of genes important in the early innate immune response, are upregulated in response to stimulation by extracellular type I interferons. The regulation of ISGs has been extensively studied in cells exposed to significant interferon stimulation, but less is known about ISG regulation in homeostatic regimes in which extracellular interferon levels are low. Using a collection of pre-existing, publicly available microarray datasets, we investigated ISG regulation at homeostasis in CD4, pulmonary epithelial, fibroblast and macrophage cells. We used a linear regression model to predict ISG expression levels from regulator expression levels. Our results suggest significant regulation of ISG expression at homeostasis, both through the ISGF3 molecule and through IRF7 and IRF8 associated pathways. We find that roughly 50% of ISGs have expression levels significantly correlated with ISGF3 expression levels at homeostasis, supporting previous results suggesting that homeostatic IFN levels have broad functional consequences. We find that ISG expression levels varied in their correlation with ISGF3, with epithelial and macrophage cells showing more correlation than CD4 and fibroblast cells. Our analysis provides a novel approach for decomposing and quantifying ISG regulation.

Optimal approaches to preventing severe community-acquired pneumonia

Introduction: Community-acquired pneumonia (CAP) has the highest rate of mortality of all infectious diseases, especially among the elderly. Severe CAP (sCAP) is defined as a CAP in which intensive care management is required and is associated with an unfavorable clinical course. Areas covered: This review aims to identify prevention strategies for reducing the incidence of CAP and optimized management of sCAP. We highlight the main prevention approaches for CAP, focusing on the latest vaccination plans and on the influence of health-risk behaviors. Lastly, we report the latest recommendations about the optimal approach for sCAP when CAP has already been diagnosed, including prompt admission to ICU, early empirical antibiotic therapy, and optimization of antibiotic use. Expert opinion: Despite improvements in the diagnosis and treatment of sCAP, more efforts are needed to combat preventable causes, including the implementation and improvement of vaccine coverage, anti-tobacco campaigns and correct oral hygiene. Moreover, future research should aim to assess the benefits of early antimicrobial therapy in primary care. Pharmacokinetic studies in the target population may help clinicians to adjust dosage regimens in critically ill patients with CAP and thus reduce rates of treatment failure.

Effect of tobacco smoking on the risk of developing community acquired pneumonia: A systematic review and meta-analysis

AIM

To summarise and quantify the effect of tobacco smoking on the risk of developing community acquired pneumonia (CAP) in adults.

METHODS

We systematically searched MEDLINE, Embase, CINAHL, PsychINFO and Web of Science, from inception to October 2017, to identify case-control and cohort studies and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist. The review protocol was registered with the PROSPERO database (CRD42018093943). Study quality was assessed by the Newcastle-Ottawa Scale. Pooled odds ratios (ORs) or hazard ratios (HRs) were estimated using a random-effects model.

RESULTS

Of 647 studies identified, 27 studies were included (n = 460,592 participants) in the systematic review. Most of the included studies were of moderate quality with a median score of six (IQR 6-7). Meta-analysis showed that current smokers (pooled OR 2.17, 95% CI 1.70-2.76, n = 13 studies; pooled HR 1.52, 95% CI 1.13-2.04, n = 7 studies) and ex-smokers (pooled OR 1.49, 95% CI 1.26-1.75, n = 8 studies; pooled HR 1.18, 95% CI 0.91-1.52, n = 6 studies) were more likely to develop CAP compared to never smokers. Although the association between passive smoking and risk of CAP in adults of all ages was not statistically significant (pooled OR 1.13, 95% CI 0.94-1.36, n = 5 studies), passive smoking in adults aged ≥65 years was associated with a 64% increased risk of CAP (pooled OR 1.64; 95% CI 1.17-2.30, n = 2 studies). Dose-response analyses of data from five studies revealed a significant trend; current smokers who smoked higher amount of tobacco had a higher risk of CAP.

CONCLUSION

Tobacco smoke exposure is significantly associated with the development of CAP in current smokers and ex-smokers. Adults aged > 65 years who are passive smokers are also at higher risk of CAP. For current smokers, a significant dose-response relationship is evident.

Compartmentalization of anti-oxidant and anti-inflammatory gene expression in current and former smokers with COPD

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) have high oxidative stress associated with the severity of the disease. Nuclear factor erythroid-2 related factor 2 (Nrf2)-directed stress response plays a critical role in the protection of lung cells to oxidative stress by upregulating antioxidant genes in response to tobacco smoke. There is a critical gap in our knowledge about Nrf-2 regulated genes in active smokers and former-smokers with COPD in different cell types from of lungs and surrogate peripheral tissues.

METHODS

We compared the expression of Nrf2 and six of its target genes in alveolar macrophages, nasal, and bronchial epithelium and peripheral blood mononuclear cells (PBMCs) in current and former smokers with COPD. We compared cell-type specific of Nrf2 and its target genes as well as markers of oxidative and inflammatory stress.

RESULTS

We enrolled 89 patients; expression all Nrf2 target gene measured were significantly higher in the bronchial epithelium from smokers compared to non-smokers. None were elevated in alveolar macrophages and only one was elevated in each of the other compartments.

CONCLUSION

Bronchial epithelium is the most responsive tissue for transcriptional activation of Nrf2 target genes in active smokers compared to former-smokers with COPD that correlated with oxidative stress and inflammatory markers. There were no consistent trends in gene expression in other cell types tested.

TRIAL REGISTRATION

Clinicaltrials.gov : NCT01335971.

Applying Integrated Exposure-Response Functions to PM2.5 Pollution in India

Fine particulate matter (PM2.5, diameter ≤2.5 μm) is implicated as the most health-damaging air pollutant. Large cohort studies of chronic exposure to PM2.5 and mortality risk are largely confined to areas with low to moderate ambient PM2.5 concentrations and posit log-linear exposure-response functions. However, levels of PM2.5 in developing countries such as India are typically much higher, causing unknown health effects. Integrated exposure-response functions for high PM2.5 exposures encompassing risk estimates from ambient air, secondhand smoke, and active smoking exposures have been posited. We apply these functions to estimate the future cause-specific mortality risks associated with population-weighted ambient PM2.5 exposures in India in 2030 using Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) model projections. The loss in statistical life expectancy (SLE) is calculated based on risk estimates and baseline mortality rates. Losses in SLE are aggregated and weighted using national age-adjusted, cause-specific mortality rates. 2030 PM2.5 pollution in India reaches an annual mean of 74 μg/m³, nearly eight times the corresponding World Health Organization air quality guideline. The national average loss in SLE is 32.5 months (95% Confidence Interval (CI): 29.7⁻35.2, regional range: 8.5⁻42.0), compared to an average of 53.7 months (95% CI: 46.3⁻61.1) using methods currently applied in GAINS. Results indicate wide regional variation in health impacts, and these methods may still underestimate the total health burden caused by PM2.5 exposures due to model assumptions on minimum age thresholds of pollution effects and a limited subset of health endpoints analyzed. Application of the revised exposure-response functions suggests that the most polluted areas in India will reap major health benefits only with substantial improvements in air quality.

Parental Perceptions and Misconceptions of Child Tobacco Smoke Exposure

Introduction

Forty percent of young children worldwide are exposed to the harmful effects of tobacco smoke, predominantly by parental smoking. Little is known about why parents regularly expose their children to these risks; perhaps parents underestimate the degree of exposure. Qualitative methods were used to investigate parental perceptions of tobacco smoke exposure.

Methods

Sixty-five in-depth interviews were conducted with parents of young children in smoking families in central Israel. Parents were asked to explain what "exposure to smoking" meant. Thematic analysis was performed, a conceptual model of perceptions was built, and misconceptions were identified.

Results

Parents reported that exposure occurs when smoke or smokers are visible, when smoke can be smelled, felt, or inhaled, or when it "reaches" an individual. Conversely, some believed that exposure does not occur in the absence of odor, visible smoke, or smokers or if smoking occurs outdoors or in indoor ventilated environments. Proximity in space and time affected perceptions of exposure; some parents believed that smoke does not spread far but dissipates rapidly. There was some uncertainty regarding whether or not exposure was occurring.

Conclusions

Awareness of child exposure to tobacco smoke among parents in this study was based on sensory perceptions in the context of the physical environment. The limited capacity of humans to perceive tobacco smoke can lead to misconceptions about exposure. In order to protect children, parents must be convinced that exposure can occur even in situations where they are unable to sense it.

Implications

Parents use sensory perceptions (sight, smell, and feel) in the context of the physical environment to assess whether or not their children are exposed to tobacco smoke. Because 85% of smoke is invisible and the sense of smell is unreliable, assessments based on sensory perceptions cannot provide accurate information about the presence of tobacco smoke. In order to protect children, parents must be convinced that exposure can occur even in situations where they are unable to sense it. The scientific information summarized here about exposure in common situations should be useful in persuading parents to protect their children.

Clinical Trial Registration

This study is registered as a Phase I study which is part of a larger research endeavor entitled: A program to protect young children from tobacco smoke exposure. Registration number: NCT01335178.

Impact of acute exposure to cigarette smoke on airway gene expression

BACKGROUND

Understanding effects of acute smoke exposure (ASE) on airway epithelial gene expression and their relationship with the effects of chronic smoke exposure may provide biological insights into the development of smoking-related respiratory diseases.

METHODS

Bronchial airway epithelial cell brushings were collected from 63 individuals without recent cigarette smoke exposure and before and 24 h after smoking three cigarettes. RNA from these samples was profiled on Affymetrix Human Gene 1.0 ST microarrays.

RESULTS

We identified 91 genes differentially expressed 24 h after ASE (false discovery rate < 0.25). ASE induced genes involved in xenobiotic metabolism, oxidative stress, and inflammation and repressed genes related to cilium morphogenesis and cell cycle. While many genes altered by ASE are altered similarly in chronic smokers, metallothionein genes are induced by ASE and suppressed in chronic smokers. Metallothioneins are also suppressed in current and former smokers with lung cancer relative to those without lung cancer.

CONCLUSIONS

Acute exposure to as little as three cigarettes and chronic smoking induce largely concordant changes in airway epithelial gene expression. Differences in short-term and long-term effects of smoking on metallothionein expression and their relationship to lung cancer requires further study given these enzymes' role in the oxidative stress response.

Epidemiologic Evidence of and Potential Mechanisms by Which Second-Hand Smoke Causes Predisposition to Latent and Active Tuberculosis

Many studies have linked cigarette smoke (CS) exposure and tuberculosis (TB) infection and disease although much fewer have studied second-hand smoke (SHS) exposure. Our goal is to review the epidemiologic link between SHS and TB as well as to summarize the effects SHS and direct CS on various immune cells relevant for TB. PubMed searches were performed using the key words "tuberculosis" with "cigarette," "tobacco," or "second-hand smoke." The bibliography of relevant papers were examined for additional relevant publications. Relatively few studies associate SHS exposure with TB infection and active disease. Both SHS and direct CS can alter various components of host immunity resulting in increased vulnerability to TB. While the epidemiologic link of these 2 health maladies is robust, more definitive, mechanistic studies are required to prove that SHS and direct CS actually cause increased susceptibility to TB.

Clearing the air: American Indian tribal college students' exposure to second hand smoke & attitudes towards smoke free campus policies

OBJECTIVE

The purpose of this study was to examine knowledge, awareness, and support for campus smoke-free policies.

PARTICIPANTS

1,256 American Indian tribal college students from three tribal colleges in the Midwest and Northern Plains.

METHODS

Data are from an observational cross-sectional study of American Indian tribal college students, collected through a web-based survey.

RESULTS

Only 40% of tribal college students reported not being exposed to second hand smoke in the past 7 days. A majority of nonsmokers (66%) agreed or strongly agreed with having a smoke-free campus, while 34.2% of smokers also agreed or strongly agreed. Overall, more than a third (36.6%) of tribal college students were not aware of their campus smoking policies.

CONCLUSIONS

Tribal campuses serving American Indian students have been much slower in adopting smoke-free campus policies. Our findings show that tribal college students would support a smoke-free campus policy.

The Impact of Early-Life Exposure to Air-borne Environmental Insults on the Function of the Airway Epithelium in Asthma

The airway epithelium is both a physical barrier protecting the airways from environmental insults and a significant component of the innate immune response. There is growing evidence that exposure of the airway epithelium to environmental insults in early life may lead to permanent changes in structure and function that underlie the development of asthma. Here we review the current published evidence concerning the link between asthma and epithelial damage within the airways and identify gaps in knowledge for future studies.

American pediatric society's 2017 John Howland award acceptance lecture: a tale of two toxicants: childhood exposure to lead and tobacco

This article summarizes the presentation of the 2017 Howland Award to Michael Weitzman, MD, at the Annual Pediatric Academic Society Meetings. It summarizes the remarkable advances in understanding the effects and pathways of exposure of the two most common and pernicious of our nation's child environmental exposures, namely lead and tobacco. It also summarizes the profound effect of the translation of these findings into prudent and effective clinical and public health policies such that exposure to both has dramatically decreased over the past 40 years due to the tenacious activities of pediatricians, other child-related professionals, government agencies at all levels, and the American Academy of Pediatrics. Research and clinical activities, although essential, were not sufficient to produce these successes, but required extensive mentoring to produce a generation of academic pediatricians capable of conducting the requisite research, and extensive advocacy by pediatricians and others to overcome the formidable inertia and outright opposition to efforts to protect our children from these exposures. Moreover, the article highlights that both of these environmental exposures have roots in social and environmental injustice and neither is solved, and that there is no safe level of exposure to either of these toxicants.

Second-hand smoke exposure in homes with children: assessment of airborne nicotine in the living room and children’s bedroom

Background

The introduction of ‘smoke-free laws’ has reduced the population’s exposure to second-hand smoke (SHS), although SHS is still an issue in homes and other public places. Children are vulnerable to its health effects, and their greatest exposure occurs at home.

Objectives

To assess airborne nicotine concentration of the living room and children’s bedroom of homes with children under 13 years of age, and to analyse factors associated with these levels.

Methods

We conducted a cross-sectional study in Barcelona in 2015–2016, selecting a convenience sample from families with at least one child under 13 years of age. The sample comprised 50 families with smokers and 50 without. We measured airborne nicotine concentrations in the living room and children’s bedroom, and, using a questionnaire administered to the parents, collected information about smoking habits at home.

Results

Homes without smokers showed nicotine concentrations below the limit of detection (<0.02 µg/m3), while those with at least one smoker showed 0.16 µg/m3 in the living room and 0.12 µg/m3 in the bedroom. When smoking was allowed inside home, these values increased to 1.04 and 0.48 µg/m3, respectively. Moreover, nicotine concentrations in both rooms were strongly correlated (r=0.89), and higher nicotine levels were associated with the number of cigarettes smoked in the living room, smoking rules, the number of smokers living at home and tobacco smell.

Conclusions

Homes with smokers present SHS in the living room and in the children’s bedroom. Therefore, programmes focused on reducing children’s SHS exposure are urgently needed.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

The use of electronic cigarettes (e-cigs) is increasing rapidly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plausible that e-cig use might affect similar inflammatory pathways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers (e.g., adolescents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the potential for inducing inflammation, albeit much less than smoking. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary biomarkers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers. Cancer Epidemiol Biomarkers Prev; 26(8); 1175-91. ©2017 AACR.

Pulmonary Abnormalities in Young, Light-Use Waterpipe (Hookah) Smokers

RATIONALE

Waterpipes, also called hookahs, are currently used by millions of people worldwide. Despite the increasing use of waterpipe smoking, there is limited data on the health effects of waterpipe smoking and there are no federal regulations regarding its use.

OBJECTIVES

To assess the effects of waterpipe smoking on the human lung using clinical and biological parameters in young, light-use waterpipe smokers.

METHODS

We assessed young, light-use, waterpipe-only smokers in comparison with lifelong nonsmokers using clinical parameters of cough and sputum scores, lung function, and chest high-resolution computed tomography as well as biological parameters of lung epithelial lining fluid metabolome, small airway epithelial (SAE) cell differential and transcriptome, alveolar macrophage transcriptome, and plasma apoptotic endothelial cell microparticles.

MEASUREMENTS AND MAIN RESULTS

Compared with nonsmokers, waterpipe smokers had more cough and sputum as well as a lower lung diffusing capacity, abnormal epithelial lining fluid metabolome profile, increased proportions of SAE secretory and intermediate cells, reduced proportions of SAE ciliated and basal cells, markedly abnormal SAE and alveolar macrophage transcriptomes, and elevated levels of apoptotic endothelial cell microparticles.

CONCLUSIONS

Young, light-use, waterpipe-only smokers have a variety of abnormalities in multiple lung-related biological and clinical parameters, suggesting that even limited waterpipe use has broad consequences on human lung biology and health. We suggest that large epidemiological studies should be initiated to investigate the harmful effects of waterpipe smoking.

Mechanistic Evaluation of the Impact of Smoking and Chronic Obstructive Pulmonary Disease on the Nasal Epithelium

Chronic obstructive pulmonary disease (COPD) is one of the major causes of chronic morbidity and mortality worldwide. The development of markers of COPD onset is hampered by the lack of accessibility to the primary target tissue, and there is a need to consider other sample sources as surrogates for biomarker research. Airborne toxicants pass through the nasal epithelium before reaching the lower airways, and the similarity with bronchial histology makes it an attractive surrogate for lower airways. In this work, we describe the transcriptomics findings from the nasal epithelia of subjects enrolled in a clinical study focusing on the identification of COPD biomarkers. Transcriptomic data were analyzed using the biological network approach that enabled us to pinpoint the biological processes affected in the upper respiratory tract in response to smoking and mild-to-moderate COPD. Our results indicated that nasal and lower airway immune responses were considerably different in COPD subjects and caution should be exercised when using upper airway samples as a surrogate for the lower airway. Nevertheless, the network approach described here could present a sensitive means of identifying smokers at risk of developing COPD.

Plausible Roles for RAGE in Conditions Exacerbated by Direct and Indirect (Secondhand) Smoke Exposure

Approximately 1 billion people smoke worldwide, and the burden placed on society by primary and secondhand smokers is expected to increase. Smoking is the leading risk factor for myriad health complications stemming from diverse pathogenic programs. First- and second-hand cigarette smoke contains thousands of constituents, including several carcinogens and cytotoxic chemicals that orchestrate chronic inflammatory responses and destructive remodeling events. In the current review, we outline details related to compromised pulmonary and systemic conditions related to smoke exposure. Specifically, data are discussed relative to impaired lung physiology, cancer mechanisms, maternal-fetal complications, cardiometabolic, and joint disorders in the context of smoke exposure exacerbations. As a general unifying mechanism, the receptor for advanced glycation end-products (RAGE) and its signaling axis is increasingly considered central to smoke-related pathogenesis. RAGE is a multi-ligand cell surface receptor whose expression increases following cigarette smoke exposure. RAGE signaling participates in the underpinning of inflammatory mechanisms mediated by requisite cytokines, chemokines, and remodeling enzymes. Understanding the biological contributions of RAGE during cigarette smoke-induced inflammation may provide critically important insight into the pathology of lung disease and systemic complications that combine during the demise of those exposed.

Persistence of circulating endothelial microparticles in COPD despite smoking cessation

INTRODUCTION

Increasing evidence links COPD pathogenesis with pulmonary capillary apoptosis. We previously demonstrated that plasma levels of circulating microparticles released from endothelial cells (EMPs) due to apoptosis are elevated in smokers with normal spirometry but low diffusion capacity, that is, with early evidence of lung destruction. We hypothesised that pulmonary capillary apoptosis persists with the development of COPD and assessed its reversibility in healthy smokers and COPD smokers following smoking cessation.

METHODS

Pulmonary function and high-resolution CT (HRCT) were assessed in 28 non-smokers, 61 healthy smokers and 49 COPD smokers; 17 healthy smokers and 18 COPD smokers quit smoking for 12 months following the baseline visit. Total EMP (CD42b-CD31+), pulmonary capillary EMP (CD42b-CD31+ACE+) and apoptotic EMP (CD42b-CD62E+/CD42b-CD31+) levels were quantified by flow cytometry.

RESULTS

Compared with non-smokers, healthy smokers and COPD smokers had elevated levels of circulating EMPs due to active pulmonary capillary endothelial apoptosis. Levels remained elevated over 12 months in healthy smokers and COPD smokers who continued smoking, but returned to non-smoker levels in healthy smokers who quit. In contrast, levels remained significantly abnormal in COPD smokers who quit.

CONCLUSIONS

Pulmonary capillary apoptosis is reversible in healthy smokers who quit, but continues to play a role in COPD pathogenesis in smokers who progressed to airflow obstruction despite smoking cessation.

TRIAL REGISTRATION NUMBER

NCT00974064; NCT01776398.

Smoking asthma phenotype: diagnostic and management challenges

PURPOSE OF REVIEW

The prevalence of active smoking in adults with asthma is similar to the general population. Smoking asthma is associated with poorer disease control, impaired response to corticosteroid therapy, accelerated decline in lung function, and increased rate of healthcare utilization. Current asthma guidelines do not provide specific treatment advice for smoking asthmatic patients. There is an urgent need for better understanding of the underlying mechanisms and effective treatment for smoking asthmatic patients.

RECENT FINDINGS

An association between both active and passive smoking and adult-onset asthma is supported by many studies.The asthma-COPD overlap syndrome (ACOS) has recently gained particular interest and smoking asthmatic patients should be evaluated for ACOS.Treatment regimens for smoking asthma include higher doses of inhaled corticosteroids (ICS), extrafine particle ICS formulations, antileukotrienes, and combinations of these options.Asthma is associated with increased risk of cardiovascular comorbidities whereas smoking is an additional strong independent risk factor for pulmonary and cardiovascular diseases. Tobacco smoking and not asthma per se seems to be the reason of poor prognosis, especially with regard to lung cancer, cardiovascular diseases, and mortality in asthmatic patients.

SUMMARY

Smoking asthma represents a common challenge to the clinician both in terms of diagnosis and management. These aspects have not been thoroughly evaluated and deserve further investigation.

The Added Value of Medical Testing in Underwriting Life Insurance

Background

In present-day life-insurance medical underwriting practice the risk assessment starts with a standard health declaration (SHD). Indication for additional medical screening depends predominantly on age and amount of insured capital. From a medical perspective it is questionable whether there is an association between the level of insured capital and medical risk in terms of mortality. The aim of the study is to examine the prognostic value of parameters from the health declaration and application form on extra mortality based on results from additional medical testing.

Methods

A history register-based cohort study was conducted including about 15.000 application files accepted between 2007 and 2010. Blood pressure, lipids, cotinine and glucose levels were used as dependent variables in logistic regression models. Resampling validation was applied using 250 bootstrap samples to calculate area under the curves (AUC’s). The AUC was used to discriminate between persons with and without at least 25% extra mortality.

Results

BMI and the overall assessment of the health declaration by an insurance physician or medical underwriter showed the strongest discrimination in multivariable analysis. Including all variables at minimum cut-off levels resulted in an AUC of 0.710 while by using a model with BMI, the assessment of the health declaration and gender, the AUC was 0.708. Including all variables at maximum cut-off levels lead to an AUC of 0.743 while a model with BMI, the assessment of the health declaration and age resulted in an AUC of 0.741.

Conclusions

The outcome of this study shows that BMI and the overall assessment of the health declaration were the dominant variables to discriminate between applicants for life-insurance with and without at least 25 percent extra mortality. The variable insured capital set by insurers as factor for additional medical testing could not be established in this study population. The indication for additional medical testing at underwriting life-insurance can possibly be done on limited variables instead of the obligatory medical testing based on age and the amount of insured capital.

Bayesian Network Inference Enables Unbiased Phenotypic Anchoring of Transcriptomic Responses to Cigarette Smoke in Humans

Microarray-based transcriptomic analysis has been demonstrated to hold the opportunity to study the effects of human exposure to, e.g., chemical carcinogens at the whole genome level, thus yielding broad-ranging molecular information on possible carcinogenic effects. Since genes do not operate individually but rather through concerted interactions, analyzing and visualizing networks of genes should provide important mechanistic information, especially upon connecting them to functional parameters, such as those derived from measurements of biomarkers for exposure and carcinogenic risk. Conventional methods such as hierarchical clustering and correlation analyses are frequently used to address these complex interactions but are limited as they do not provide directional causal dependence relationships. Therefore, our aim was to apply Bayesian network inference with the purpose of phenotypic anchoring of modified gene expressions. We investigated a use case on transcriptomic responses to cigarette smoking in humans, in association with plasma cotinine levels as biomarkers of exposure and aromatic DNA-adducts in blood cells as biomarkers of carcinogenic risk. Many of the genes that appear in the Bayesian networks surrounding plasma cotinine, and to a lesser extent around aromatic DNA-adducts, hold biologically relevant functions in inducing severe adverse effects of smoking. In conclusion, this study shows that Bayesian network inference enables unbiased phenotypic anchoring of transcriptomics responses. Furthermore, in all inferred Bayesian networks several dependencies are found which point to known but also to new relationships between the expression of specific genes, cigarette smoke exposure, DNA damaging-effects, and smoking-related diseases, in particular associated with apoptosis, DNA repair, and tumor suppression, as well as with autoimmunity.

Reduced gene expression levels after chronic exposure to high concentrations of air pollutants

We analyzed the ability of particulate matter (PM) and chemicals adsorbed onto it to induce diverse gene expression profiles in subjects living in two regions of the Czech Republic differing in levels and sources of the air pollution. A total of 312 samples from polluted Ostrava region and 154 control samples from Prague were collected in winter 2009, summer 2009 and winter 2010. The highest concentrations of air pollutants were detected in winter 2010 when the subjects were exposed to: PM of aerodynamic diameter <2.5μm (PM2.5) (70 vs. 44.9μg/m(3)); benzo[a]pyrene (9.02 vs. 2.56ng/m(3)) and benzene (10.2 vs. 5.5μg/m(3)) in Ostrava and Prague, respectively. Global gene expression analysis of total RNA extracted from leukocytes was performed using Illumina Expression BeadChips microarrays. The expression of selected genes was verified by quantitative real-time PCR (qRT-PCR). Gene expression profiles differed by locations and seasons. Despite lower concentrations of air pollutants a higher number of differentially expressed genes and affected KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways was found in subjects from Prague. In both locations immune response pathways were affected, in Prague also neurodegenerative diseases-related pathways. Over-representation of the latter pathways was associated with the exposure to PM2.5. The qRT-PCR analysis showed a significant decrease in expression of APEX, ATM, FAS, GSTM1, IL1B and RAD21 in subjects from Ostrava, in a comparison of winter 2010 and summer 2009. In Prague, an increase in gene expression was observed for GADD45A and PTGS2. In conclusion, high concentrations of pollutants in Ostrava were not associated with higher number of differentially expressed genes, affected KEGG pathways and expression levels of selected genes. This observation suggests that chronic exposure to air pollution may result in reduced gene expression response with possible negative health consequences.

Protocol for a human in vivo model of acute cigarette smoke inhalation challenge in smokers with COPD: monitoring the nasal and systemic immune response using a network biology approach

INTRODUCTION

Cigarette smoke contributes to a diverse range of diseases including chronic obstructive pulmonary disease (COPD), cardiovascular disorders and many cancers. There currently is a need for human challenge models, to assess the acute effects of a controlled cigarette smoke stimulus, followed by serial sampling of blood and respiratory tissue for advanced molecular profiling. We employ precision sampling of nasal mucosal lining fluid by absorption to permit soluble mediators measurement in eluates. Serial nasal curettage was used for transcriptomic analysis of mucosal tissue.

METHODS AND ANALYSIS

Three groups of strictly defined patients will be studied: 12 smokers with COPD (GOLD Stage 2) with emphysema, 12 matched smokers with normal lung function and no evidence of emphysema, and 12 matched never smokers with normal spirometry. Patients in the smoking groups are current smokers, and will be given full support to stop smoking immediately after this study. In giving a controlled cigarette smoke stimulus, all patients will have abstained from smoking for 12 h, and will smoke two cigarettes with expiration through the nose in a ventilated chamber. Before and after inhalation of cigarette smoke, a series of samples will be taken from the blood, nasal mucosal lining fluid and nasal tissue by curettage. Analysis of plasma nicotine and metabolites in relation to levels of soluble inflammatory mediators in nasal lining fluid and blood, as well as assessing nasal transcriptomics, ex vivo blood platelet aggregation and leucocyte responses to toll-like receptor agonists will be undertaken.

IMPLICATIONS

Development of acute cigarette smoke challenge models has promise for the study of molecular effects of smoking in a range of pathological processes.

ETHICS AND DISSEMINATION

This study was approved by the West London National Research Ethics Committee (12/LO/1101). The study findings will be presented at conferences and will be reported in peer-reviewed journals.

Tobacco smoking increases the risk for death from pneumococcal pneumonia

BACKGROUND

Active smoking increases the risk of developing community-acquired pneumonia (CAP) and invasive pneumococcal disease, although its impact on mortality in pneumococcal CAP outcomes remains unclear. The aim of this study was to investigate the influence of current smoking status on pneumococcal CAP mortality.

METHODS

We performed a multicenter, prospective, observational cohort study in 4,288 hospitalized patients with CAP. The study group consisted of 892 patients with pneumococcal CAP: 204 current smokers (22.8%), 387 nonsmokers (43.4%), and 301 exsmokers (33.7%).

RESULTS

Mortality at 30 days was 3.9%: 4.9% in current smokers vs 4.3% in nonsmokers and 2.6% in exsmokers. Current smokers with CAP were younger (51 years vs 74 years), with more alcohol abuse and fewer cardiac, renal, and asthma diseases. Current smokers had lower CURB-65 (confusion, uremia, respiratory rate, BP, age ≥ 65 years) scores, although 40% had severe sepsis at diagnosis. Current smoking was an independent risk factor (OR, 5.0; 95% CI, 1.8-13.5; P = .001) for 30-day mortality of pneumococcal CAP after adjusting for age (OR, 1.06; P = .001), liver disease (OR, 4.5), sepsis (OR, 2.3), antibiotic adherence to guidelines, and first antibiotic dose given < 6 h. The independent risk effect of current smokers remained when compared only with nonsmokers (OR, 4.0; 95% CI, 1.3-12.6; P = .015) or to exsmokers (OR, 3.9; 95% CI, 1.09-4.95; P = .02).

CONCLUSIONS

Current smokers with pneumococcal CAP often develop severe sepsis and require hospitalization at a younger age, despite fewer comorbid conditions. Smoking increases the risk of 30-day mortality independently of tobacco-related comorbidity, age, and comorbid conditions. Current smokers should be actively targeted for preventive strategies.

Tobacco exposure and susceptibility to tuberculosis: is there a smoking gun?

In many regions of the world, there is a great overlap between the prevalence of cigarette smoke exposure and tuberculosis. Despite the large body of epidemiologic evidence that tobacco smoke exposure is associated with increased tuberculosis infection, active disease, severity of disease, and mortality from tuberculosis, these studies cannot distinguish whether the mechanism is principally through direct impairment of anti-tuberculosis immunity by cigarette smoke or due to potential confounders that increase risk for tuberculosis and are commonly associated with smoking--such as poverty, malnutrition, and crowded living conditions. While there are several in vivo murine and in vitro macrophage studies showing cigarette smoke impairs control of tuberculous infection, little is known of the molecular and cellular mechanisms by which this impairment occurs. Herein, we highlight the key findings of these studies. Additionally, we review key immune cells that play critical roles in host-defense or pathogenesis of tuberculosis and generate a hypothesis-driven discussion of the possible mechanisms by which cigarette smoke impairs or enhances their functions, respectively, ultimately resulting in compromised immunity against tuberculosis.

Quantification of biological network perturbations for mechanistic insight and diagnostics using two-layer causal models

BACKGROUND

High-throughput measurement technologies such as microarrays provide complex datasets reflecting mechanisms perturbed in an experiment, typically a treatment vs. control design. Analysis of these information rich data can be guided based on a priori knowledge, such as networks or set of related proteins or genes. Among those, cause-and-effect network models are becoming increasingly popular and more than eighty such models, describing processes involved in cell proliferation, cell fate, cell stress, and inflammation have already been published. A meaningful systems toxicology approach to study the response of a cell system, or organism, exposed to bio-active substances requires a quantitative measure of dose-response at network level, to go beyond the differential expression of single genes.

RESULTS

We developed a method that quantifies network response in an interpretable manner. It fully exploits the (signed graph) structure of cause-and-effect networks models to integrate and mine transcriptomics measurements. The presented approach also enables the extraction of network-based signatures for predicting a phenotype of interest. The obtained signatures are coherent with the underlying network perturbation and can lead to more robust predictions across independent studies. The value of the various components of our mathematically coherent approach is substantiated using several in vivo and in vitro transcriptomics datasets. As a proof-of-principle, our methodology was applied to unravel mechanisms related to the efficacy of a specific anti-inflammatory drug in patients suffering from ulcerative colitis. A plausible mechanistic explanation of the unequal efficacy of the drug is provided. Moreover, by utilizing the underlying mechanisms, an accurate and robust network-based diagnosis was built to predict the response to the treatment.

CONCLUSION

The presented framework efficiently integrates transcriptomics data and "cause and effect" network models to enable a mathematically coherent framework from quantitative impact assessment and data interpretation to patient stratification for diagnosis purposes.

Passive smoking at home is a risk factor for community-acquired pneumonia in older adults: a population-based case-control study

OBJECTIVE

To assess whether passive smoking exposure at home is a risk factor for community-acquired pneumonia (CAP) in adults.

SETTING

A population-based case-control study was designed in a Mediterranean area with 860 000 inhabitants >14 years of age.

PARTICIPANTS

1003 participants who had never smoked were recruited.

PRIMARY AND SECONDARY OUTCOME MEASURES

Risk factors for CAP, including home exposure to passive smoking, were registered. All new cases of CAP in a well-defined population were consecutively recruited during a 12-month period.

METHODS

A population-based case-control study was designed to assess risk factors for CAP, including home exposure to passive smoking. All new cases of CAP in a well-defined population were consecutively recruited during a 12-month period. The subgroup of never smokers was selected for the present analysis.

RESULTS

The study sample included 471 patients with CAP and 532 controls who had never smoked. The annual incidence of CAP was estimated to be 1.14 cases×10(-3) inhabitants in passive smokers and 0.90×10(-3) in non-passive smokers (risk ratio (RR) 1.26; 95% CI 1.02 to 1.55) in the whole sample. In participants ≥65 years of age, this incidence was 2.50×10(-3) in passive smokers and 1.69×10(-3) in non-passive smokers (RR 1.48, 95% CI 1.08 to 2.03). In this last age group, the percentage of passive smokers in cases and controls was 26% and 18.1%, respectively (p=0.039), with a crude OR of 1.59 (95% CI 1.02 to 2.38) and an adjusted (by age and sex) OR of 1.56 (95% CI 1.00 to 2.45).

CONCLUSIONS

Passive smoking at home is a risk factor for CAP in older adults (65 years or more).

Controlled experiments measuring personal exposure to PM2.5 in close proximity to cigarette smoking

Few measurements of exposure to secondhand smoke (SHS) in close proximity to a smoker are available. Recent health studies have demonstrated an association between acute (<2 h) exposures to high concentrations of SHS and increased risk of cardiovascular and respiratory disease. We performed 15 experiments inside naturally ventilated homes and 16 in outdoor locations, each with 2-4 non-smokers sitting near a cigarette smoker. The smoker's and non-smokers' real-time exposures to PM2.5 from SHS were measured by using TSI SidePak monitors to sample their breathing zones. In 87% of the residential indoor experiments, the smoker received the highest average exposure to SHS, with PM2.5 concentrations ranging from 50-630 μg/m(3) . During the active smoking period, individual non-smokers sitting within approximately 1 m of a smoker had average SHS exposures ranging from negligible up to >160 μg/m(3) of PM2.5 . The average incremental exposure of the non-smokers was higher indoors (42 μg/m(3) , n = 35) than outdoors (29 μg/m(3) , n = 47), but the overall indoor and outdoor frequency distributions were similar. The 10-s PM2.5 averages during the smoking periods showed great variability, with multiple high concentrations of short duration (microplumes) both indoors and outdoors.

Community-acquired pneumonia among smokers

Recent studies have left absolutely no doubt that tobacco increases susceptibility to bacterial lung infection, even in passive smokers. This relationship also shows a dose-response effect, since the risk reduces spectacularly 10 years after giving up smoking, returning to the level of non-smokers. Streptococcus pneumoniae is the causative microorganism responsible for community-acquired pneumonia (CAP) most frequently associated with smoking, particularly in invasive pneumococcal disease and septic shock. It is not clear how it acts on the progress of pneumonia, but there is evidence to suggest that the prognosis for pneumococcal pneumonia is worse. In CAP caused by Legionella pneumophila, it has also been observed that smoking is the most important risk factor, with the risk rising 121% for each pack of cigarettes smoked a day. Tobacco use may also favor diseases that are also known risk factors for CAP, such as periodontal disease and upper respiratory viral infections. By way of prevention, while giving up smoking should always be proposed, the use of the pneumococcal vaccine is also recommended, regardless of the presence of other comorbidities.

Systems approaches evaluating the perturbation of xenobiotic metabolism in response to cigarette smoke exposure in nasal and bronchial tissues

Capturing the effects of exposure in a specific target organ is a major challenge in risk assessment. Exposure to cigarette smoke (CS) implicates the field of tissue injury in the lung as well as nasal and airway epithelia. Xenobiotic metabolism in particular becomes an attractive tool for chemical risk assessment because of its responsiveness against toxic compounds, including those present in CS. This study describes an efficient integration from transcriptomic data to quantitative measures, which reflect the responses against xenobiotics that are captured in a biological network model. We show here that our novel systems approach can quantify the perturbation in the network model of xenobiotic metabolism. We further show that this approach efficiently compares the perturbation upon CS exposure in bronchial and nasal epithelial cells in vivo samples obtained from smokers. Our observation suggests the xenobiotic responses in the bronchial and nasal epithelial cells of smokers were similar to those observed in their respective organotypic models exposed to CS. Furthermore, the results suggest that nasal tissue is a reliable surrogate to measure xenobiotic responses in bronchial tissue.