Research opportunities related to establishing standards for tobacco products under the Family Smoking Prevention and Tobacco Control Act

Role of parental smoking and environmental tobacco smoke exposure in childhood cancer: A study using hair cotinine analysis and questionnaires

OBJECTIVES

In the etiology of childhood cancers, many genetic and environmental factors play a role. One of these factors could be cigarette smoking, and the main source of tobacco smoke exposure of children is parental smoking. However, establishing a causal relationship between parental smoking and childhood cancers has proven challenging due to difficulties in accurately detecting tobacco smoke exposure METHODS: To address this issue, we used hair cotinine analysis and a questionnaire to get information about tobacco smoke exposures of pediatric cancer patients and healthy children. A total of 104 pediatric cancer patients and 99 healthy children participated in our study. Parental smoking behaviors (pre-conceptional, during pregnancy, and current smoking) and environmental tobacco smoke (ETS) exposures of children are compared.

RESULTS

We have found no differences between two groups by means of maternal smoking behaviors. However, the rates of paternal pre-conceptional smoking and smoking during pregnancy were significantly low in cancer patients (p < .05). These data suggest that social desirability bias among fathers of cancer patients may have contributed to this discrepancy. According to questionnaire, cancer patients had significantly lower ETS exposures than healthy children (p < .05). However, ETS exposure assessment through cotinine analysis demonstrated that cancer patients had higher exposure to ETS compared to healthy children (p < .001).

CONCLUSION

Our findings provide evidence supporting the potential role of smoking as a risk factor for childhood cancers. This study also revealed that questionnaires could cause biases. We suggest that cotinine analysis along with validated questionnaires can be used to prevent biases in studies of tobacco smoke in the etiology of childhood cancers.

Greater physical activity levels are associated with lower prevalence of tumors and risk of cancer in Spanish population: A cross-sectional study

Cancer is a leading cause of death worldwide and insufficient physical activity is a significant risk factor. This study analyzed the tumor prevalence based on sex, age, smoking, BMI, and physical activity level (PAL) in the Spanish people. Data from the Spanish National Health Survey (ENSE) was used, comprising a sample of 17,704 people diagnosed with malignant tumors. The findings revealed compelling associations (P < 0.001) between all variables examined and the prevalence of malignant tumors. Notably, women exhibited a higher prevalence than men (P < 0.05). Furthermore, individuals classified as obese displayed a greater prevalence of tumors than those within the normal weight range (P < 0.05). The analysis also showed that the inactive group had a higher prevalence of malignant tumors than the active group (P < 0.05). This study identified significant dependency relationships (P < 0.001) between PAL and the various population groups examined. Additionally, the general population analyzed in the ENSE2017 study demonstrated a reduced risk of developing malignant tumors among the active (P < 0.05) and very active groups (P < 0.05) compared to the inactive group. This risk reduction was consistently observed across different subgroups, including men, women, specific age groups, smoking, and BMI categories (P < 0.05). This study highlighted the importance of regular physical activity in reducing the risk and prevalence of malignant tumors in the Spanish population. These findings underscore the critical role of engaging in physical activity as a protective measure against cancer. Encouraging individuals to adopt an active lifestyle could significantly contribute to cancer prevention efforts and promote overall well-being.

The role of N6-methyladenosine methylation in PAHs-induced cancers

Polycyclic aromatic hydrocarbons (PAHs), which are a wide range of environmental toxicants, may act on humans through inhalation, ingestion, and skin contact, resulting in a range of toxic reactions. Epidemiological studies showed that long-term exposure to PAHs in the occupational and living environment results in a substantial rise in the incidence rate of many cancers in the population, so the prevention and treatment of these diseases have become a major worldwide public health problem. N6-methyladenosine (m6A) modification greatly affects the metabolism of RNA and is implicated in the etiopathogenesis of many kinds of diseases. In addition, m6A-binding proteins have an important role in disease development. The abnormal expression of these can cause the malignant proliferation, migration, invasion, and metastasis of cancers. Furthermore, a growing number of studies revealed that environmental toxicants are one of the cancer risk factors and are related to m6A modifications. Exposure to environmental toxicants can alter the methylation level of m6A and the expression of the m6A-binding protein, thus promoting the occurrence and development of cancers through diverse mechanisms. m6A may serve as a biomarker for early environmental exposure. Through the study of m6A, we can find the health injury early, thus providing a new sight for preventing and curing environmental health-related diseases.

NIR and THz spectroscopy: An experimental investigation toward nicotine-related devices

This study examined the content of nicotine-delivery products using terahertz time-domain spectroscopy (THz-TDS) and breath ethylene investigated with CO2 laser photoacoustic spectroscopy (CO2 LPAS) system as a biomarker of oxidative stress after smoking. The THz-TDS method provided valuable information on the transmission spectra of tobacco and nicotine in smoking products. From the CO2 LPAS data it was observed that in cigarette (TC) smoking the mean breath ethylene was 687 parts per billion (ppb), while in electronic cigarettes and tobacco heating devices smoking the mean ethylene was 56 ppb and 48 ppb, respectively. The main finding was that TC showed higher transmission in the THz region producing a higher oxidative stress on the body.

A comprehensive review on triple R eco-management strategies to reduce, reuse and recycle of hazardous cigarette butts

Cigarettes are the globally consumed product that contributes to public health problems and is the source of the most prevalent form of litter in the world, Cigarette butts. Cigarette butts are a major source 4000 toxic chemicals, affecting the health of wildlife, humans, and the environment and their decomposition can take years due to the resistance of cellulose acetate to bacterial and fungal degradation. In 2016, the world production of cigarettes exceeded 5.7 trillion, with the majority of them consisting of cellulose acetate filters. Consequently, a massive amount of hazardous waste leaches out in the environment. Incineration and landfilling are methods of disposal, but they can result in the emission of harmful fumes and be costly. To combat this environmental issue, researchers have explored the recycling of cigarette butts in various materials, including asphalt concrete, fired clay bricks, and as a carbon source, among others. Various approaches can be used to reduce cigarette butts pollution, but efficient collection logistics by consumers remains a crucial factor for successful recycling. This paper provides innovative solutions to mitigate the cigarette butts litter problem and the feasibility of recycling methods. Despite recent progress in cigarette butts recycling solutions, there is still much room for research in this area.

Molecular insights into the role of electronic cigarettes in oral carcinogenesis

Electronic cigarette (EC) usage or vaping has seen a significant rise in recent years across various parts of the world. They have been publicized as a safe alternative to smoking; however, this is not supported strongly by robust research evidence. Toxicological analysis of EC liquid and aerosol has revealed presence of several toxicants with known carcinogenicity. Oral cavity is the primary site of exposure of both cigarette smoke and EC aerosol. Role of EC in oral cancer is not as well-researched as that of traditional smoking. However, several recent studies have shown that it can lead to a wide range of potentially carcinogenic molecular events in oral cells. This review delineates the oral carcinogenesis potential of ECs at the molecular level, providing a summary of the effects of EC usage on cancer therapy resistance, cancer stem cells (CSCs), immune evasion, and microbiome dysbiosis, all of which may lead to increased tumor malignancy and poorer patient prognosis. This review of literature indicates that ECs may not be as safe as they are perceived to be, however further research is needed to definitively determine their oncogenic potential.

Development and validation of the health belief model questionnaire to promote smoking cessation for nasopharyngeal cancer prevention: a cross-sectional study

OBJECTIVE

Lifestyle-induced nasopharyngeal carcinoma is a serious but preventable risk factor. This study serves to develop and validate a questionnaire that aims to predict the health behavioural intention on smoking cessation in Sarawak, Malaysia using the Health Belief Model (HBM).

DESIGN

A cross-sectional study.

SETTING

Urban and suburban areas in Sarawak, Malaysia.

PARTICIPANTS

The preliminary items of the instrument were developed after extensive literature review. The instrument was translated into the Malay language using the forward-backwards method before commencing with the content validity by a panel of 10 experts. Face validity was done both quantitatively and qualitatively by 10 smokers. The construct validity of the instrument was evaluated through exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). A total of 100 smokers participated in phase 1 for EFA, while 171 smokers participated in phase 2 for CFA. Internal consistency was measured using Cronbach's alpha coefficients to evaluate the reliability.

RESULTS

In the exploratory stage, the factor loading of each item remained within the acceptable threshold. The final revised CFA yielded appropriate fit of the seven-factor model with the following model fit indices: χ²=641.705; df=500; p<0.001; comparative fit index=0.953; Tucker-Lewis Index=0.948; root mean square error of approximation=0.041. Satisfactory convergent validity and divergent validity were shown, with the exception of one pairwise construct. The internal reliability of these scales was above the desirable threshold, with Cronbach's alpha coefficients ranging from 0.705 to 0.864 and 0.838 to 0.889 in phases 1 and 2, respectively.

CONCLUSIONS

The study substantiated the instrument to be valid and reliable for predicting smokers' health behavioural intention to reduce cancer risk. The instrument is made up of 34 items, categorised into two sections, six HBM constructs and health behavioural intention. The instrument can be utilised for other smoking cessation-related cancers in different at-risk populations.

Thirdhand Exposures to Tobacco-Specific Nitrosamines through Inhalation, Dust Ingestion, Dermal Uptake, and Epidermal Chemistry

Tobacco-specific nitrosamines (TSNAs) are emitted during smoking and form indoors by nitrosation of nicotine. Two of them, N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are human carcinogens with No Significant Risk Levels (NSRLs) of 500 and 14 ng day^-1, respectively. Another TSNA, 4-(methylnitrosamino)-4-(3-pyridyl) butanal (NNA), shows genotoxic and mutagenic activity in vitro. Here, we present additional evidence of genotoxicity of NNA, an assessment of TSNA dermal uptake, and predicted exposure risks through different pathways. Dermal uptake was investigated by evaluating the penetration of NNK and nicotine through mice skin. Comparable mouse urine metabolite profiles suggested that both compounds were absorbed and metabolized via similar mechanisms. We then investigated the effects of skin constituents on the reaction of adsorbed nicotine with nitrous acid (epidermal chemistry). Higher TSNA concentrations were formed on cellulose and cotton substrates that were precoated with human skin oils and sweat compared to clean substrates. These results were combined with reported air, dust, and surface concentrations to assess NNK intake. Five different exposure pathways exceeded the NSRL under realistic scenarios, including inhalation, dust ingestion, direct dermal contact, gas-to-skin deposition, and epidermal nitrosation of nicotine. These results illustrate potential long-term health risks for nonsmokers in homes contaminated with thirdhand tobacco smoke.

Carcinogenic components of tobacco and tobacco smoke: A 2022 update

Tobacco and tobacco smoke contain a complex mixture of over 9500 chemical compounds, many of which have been recognized as hazardous to human health by regulatory agencies. In 2012, the U.S. Food and Drug Administration established a list of harmful and potentially harmful constituents in unburned tobacco and tobacco smoke, 79 of which are considered as carcinogens. Over the past 10 years, with advancing analytical technology, significant amounts of new data have been published, increasing our understanding of levels of carcinogens in tobacco products. The International Agency for Research on Cancer (IARC) has released 35 monographs since 2012, with an increasing number of compounds in unburned tobacco and tobacco smoke classified as carcinogens. In this paper, we provide an updated list of IARC-classified carcinogens in unburned tobacco and tobacco mainstream smoke. A total of 83 carcinogens has been identified - 37 in unburned tobacco and 80 in tobacco smoke - with their occurrence levels reported since 2012. No clear decreasing trends were observed for any of these carcinogens in recent years. Surveillance of the levels of tobacco carcinogens as well as regulatory actions are needed to ensure control of their levels so that potential reduced risks of cancer and other diseases may be achieved.

Alleviation of nicotine-induced reproductive disorder, clastogenicity, and histopathological alterations by fenugreek saponin bulk and nanoparticles in male rats

Nicotine is the most abundant ingredient in cigarette smoking and has serious side effects on the lung, heart, reproductive system, and many other human organs. Saponins extracted from many plants exhibit multiple biological actions such as anti-cancer effects. Therefore, the possible protective effect of fenugreek saponin (FS) and nanofenugreek saponin (NFS) against nicotine-induced toxicity in male rats was investigated in this study. Animals were divided into a control group and the nicotine (1.5 mg/kg/day), FS (25, 50, and 100 mg/kg/day), or/and NFS (20, 40, and 80 mg/kg/day) administered groups. Micronucleus assay, histopathological, and sperm abnormality examinations as well as measurement of the acetylcholinesterase (AChE) gene expression were conducted. Our findings revealed that nicotine treatment induced significant increases in the incidence of micronucleus, sperm abnormalities, and expression levels of AChE in addition to inducing histopathological changes in rat testis. On the other hand, administration of FS or NFS with nicotine significantly decreased the incidence of micronuclei and the percentage of sperm abnormalities as well as the expression levels of AChE gene. Moreover, nicotine-induced histological alterations were reduced by given FS or NFS with nicotine. In conclusion, nicotine-induced sperm abnormalities, chromosomal damage, and histological injuries were mitigated by administration of FS or NFS with nicotine, and thus, FS and NFS could be used as ameliorating agents against nicotine toxicity.

Increased oxidative stress and effects on inflammatory cytokine secretion by heated tobacco products aerosol exposure to mice

Although the amount of chemicals in heated tobacco products (HTPs) aerosols is reduced compared to conventional combustible cigarette smoke, the association between HTPs and reduced health effects remains unclear. In this study, we hypothesized that exposure to IQOS, an HTP, would increase oxidative stress and affect the secretion of inflammatory cytokines. First, C57BL/6 mice exposed to IQOS aerosols were evaluated to determine the adverse effects of IQOS exposure. IQOS exposure significantly decreased the concentration of GSH in alveolar macrophages in a dose-dependent manner and increased the percentage of GSSG in lung tissues. These results indicate that IQOS exposure increases oxidative stress, and GSH is consumed to remove oxidative stress. In addition, foamy alveolar macrophages were observed in the bronchial alveolar lavage fluid after IQOS exposure. Although the concentration of inflammatory cytokines, IL-6, and GM-CSF, in the plasma increased significantly after IQOS exposure, there were no significant changes in other cytokines. These results indicate that short-term exposure to IQOS aerosols may increase oxidative stress and induce the secretion of inflammatory cytokines. Lastly, the longer-term effects of IQOS aerosols exposure should be evaluated in the future.

Identification of SRXN1 and KRT6A as Key Genes in Smoking-Related Non-Small-Cell Lung Cancer Through Bioinformatics and Functional Analyses

Background

Lung cancer is the leading cause of cancer-related mortality worldwide. Although cigarette smoking is an established risk factor for lung cancer, few reliable smoking-related biomarkers for non-small-cell lung cancer (NSCLC) are available. An improved understanding of these biomarkers would further the development of new biomarker-targeted therapies and lead to improvements in overall patient survival.

Methods

We performed bioinformatic analysis to screened potential target genes, then quantitative PCR, western, siRNA, CCK-8, flow cytometry, tumorigenicity assays in nude mice were performed to validated the function.

Results

In this study, we identified 83 smoking-related genes (SRGs) based on an integration analysis of two Gene Expression Omnibus (GEO) datasets, and 27 hub SRGs with potential carcinogenic effects by analyzing a dataset of smokers with NSCLC in The Cancer Genome Atlas (TCGA) database. A survival analysis revealed three genes with potential prognostic value, namely SRXN1, KRT6A and JAKMIP3. A univariate Cox analysis revealed significant associations of elevated SRXN1 and KRT6A expression with prognosis. A receiver operating characteristic (ROC) curve analysis indicated the high diagnostic value of SRXN1 and KRT6A for smoking and cancer. Quantitative PCR and western blotting validated the increased expression of SRXN1 and KRT6A mRNA and protein, respectively, in lung cancer cell lines and NSCLC tissues. In patients with NSCLC, SRXN1 and KRT6A expression was associated with the tumor–node–metastasis (TNM) stage, presence of metastasis, history of smoking and daily smoking consumption. Furthermore, inhibition of SRXN1 or KRT6A suppressed viability and enhanced apoptosis in the A549 human lung carcinoma cell line. Tumorigenicity assays in nude mice confirmed that the siRNA-mediated downregulation of SRXN1 and KRT6A expression inhibited tumor growth in vivo.

Conclusions

In summary, SRXN1 and KRT6A act as oncogenes in NSCLC and might be potential biomarkers of smoking exposure and the early diagnosis and prognosis of NSCLC in smokers, which is vital for lung cancer therapy.

Nicotine promotes chronic obstructive pulmonary disease via inducing pyroptosis activation in bronchial epithelial cells

Nicotine is one of the primary components in cigarettes, which is responsible for addiction. Numerous studies have investigated the effects of nicotine on pulmonary disease. The health of epithelial cells is important in the development of chronic obstructive pulmonary disease (COPD). Accumulating evidence has suggested that epithelial cell death may initiate or contribute to the progression of a number of lung diseases via airway remodeling. Pyroptosis is a unique form of inflammatory cell death mediated by the activation of caspase‑1 and the NOD‑like receptor protein‑3 (NLRP3) inflammasome. The present study aimed to evaluate whether pyroptosis of epithelial cells was involved in the progression of COPD. The normal human bronchial epithelial cell line 16HBE was treated with 0.1 or 1 µM nicotine. Then the proliferation ability of 16HBE cells was detected by CCK‑8. Cell death was detected by flow cytometry analysis and TUNEL assay. Subsequently, the levels of pro‑caspase 1, caspase 1, IL‑1β, IL‑18, NLRP3, ASC and cleaved GSDMD were examined by western blotting. It was revealed that nicotine treatment significantly induced cell death and suppressed proliferation of 16HBE cells. Furthermore, nicotine exposure increased the expression levels of caspase‑1, IL‑1β, IL‑18, NLRP3, apoptosis‑associated speck‑like protein and gasdermin D in 16HBE cells. Therefore, the present study concluded that nicotine treatment induced pyroptosis in 16HBE cells, which may be associated with the progression of COPD.

A newly developed aerosol exposure apparatus for heated tobacco products for in vivo experiments can deliver both particles and gas phase with high recovery and depicts the time-dependent variation in nicotine metabolites in mouse urine

INTRODUCTION

There is no standardized aerosol exposure apparatus to deliver heated tobacco products (HTPs) for in vivo experiments. Therefore, we developed a novel HTPs aerosol exposure apparatus for mice and demonstrated that nicotine and other chemicals in HTPs aerosol generated by the apparatus can be delivered to mice which replicate human smoke.

METHODS

The amounts of nicotine, tar, and carbon monoxide (CO) in IQOS (Marlboro Regular HeatSticks™) aerosol generated by two types of apparatuses were determined. C57BL/6N mice were exposed to IQOS aerosol, followed by determination of the urinary nicotine metabolites. Further, the skin surface temperature of mice was monitored to confirm the vasoconstriction action of nicotine.

RESULTS

The amounts of chemicals in IQOS aerosol by the novel air push-in inhalation apparatus for HTPs (APIA) was equivalent to that of the analytical vaping machine (LM4E) [1.60 ± 0.08 (APIA) vs 1.46 ± 0.07 mg/stick (LM4E) in nicotine and 0.55 ± 0.04 (APIA) vs 0.45 ± 0.01 mg/stick (LM4E) in CO]. After mice were exposed to IQOS aerosol by APIA, the urinary nicotine metabolites levels were determined; peak values in cotinine and 3-hydroxycotinine were 6.82 μg/mg creatinine at 1 h after exposure and 32.9 μg/mg creatinine at 2 h after exposure, respectively. The skin surface temperature decreased and was lower (33.5°C ± 0.5°C) at 30 min than before exposure (37.6°C ± 0.8°C).

CONCLUSIONS

The new apparatus for HTPs aerosol exposure to mice showed good performances in terms of both chemical analysis of collected aerosol and fluctuations in the urinary nicotine metabolites.

Switching to Progressively Reduced Nicotine Content Cigarettes in Smokers With Low Socioeconomic Status: A Double-Blind Randomized Clinical Trial

INTRODUCTION

The Food and Drug Administration issued an advanced notice of proposed rulemaking for setting a product standard for nicotine levels in cigarettes, with an emphasis on minimally or non-addicting very low nicotine content (VLNC).

METHODS

A 33 week, two-arm, double-blind randomized trial conducted in Hershey, Pennsylvania, USA and Washington, DC, USA included adult daily cigarette smokers (≥5 cigarettes per day) with less than a college degree, and who had no plans to quit within the next six months. Participants were randomized to either reduced nicotine content (RNC) study cigarettes tapered every three weeks to a final VLNC (0.2 mg/cigarette) for six weeks or to usual nicotine content (UNC) study cigarettes (11.6 mg/cigarette). Outcomes included acceptability of study cigarettes measured by attrition (primary outcome), compliance, reduction in cigarette dependence and tobacco biomarkers, and post-intervention cessation.

RESULTS

The RNC (n = 122) versus UNC (n = 123) group had higher attrition (adjusted Hazard Ratio 3.4; 95% confidence interval [CI] 1.99 to 5.81). At the end of the intervention, cotinine levels were 50% lower in the RNC group (mean group difference -137 ng/mL; 95% CI -172, -102). The RNC group smoked fewer CPD (-4.1; 95% CI -6.44, -1.75) and had lower carbon monoxide levels (-4.0 ppm; 95% CI -7.7, -0.4). Forty seven percent (29/62) of the RNC group were biochemically-confirmed compliant with smoking VLNC cigarettes (mean cotinine = 8.9 ng/ml). At three month follow-up, only compliant VLNC smokers quit with an assisted quit attempt (N = 6/22, 27%).

CONCLUSIONS

This study supports a VLNC standard in cigarettes.

IMPLICATIONS

Differential dropout and noncompliance indicate some smokers had difficulty transitioning to cigarettes with reduced nicotine. These smokers will benefit from supplemental nicotine in medicinal or noncombustible tobacco products if a nicotine reduction standard is established. Other smokers successfully transitioned to very low nicotine content cigarettes exclusively and substantially reduced their exposure to nicotine.

Biochemistry of nicotine metabolism and its relevance to lung cancer

Nicotine is the key addictive constituent of tobacco. It is not a carcinogen, but it drives smoking and the continued exposure to the many carcinogens present in tobacco. The investigation into nicotine biotransformation has been ongoing for more than 60 years. The dominant pathway of nicotine metabolism in humans is the formation of cotinine, which occurs in two steps. The first step is cytochrome P450 (P450, CYP) 2A6–catalyzed 5′-oxidation to an iminium ion, and the second step is oxidation of the iminium ion to cotinine. The half-life of nicotine is longer in individuals with low P450 2A6 activity, and smokers with low activity often decrease either the intensity of their smoking or the number of cigarettes they use compared with those with “normal” activity. The effect of P450 2A6 activity on smoking may influence one's tobacco-related disease risk. This review provides an overview of nicotine metabolism and a summary of the use of nicotine metabolite biomarkers to define smoking dose. Some more recent findings, for example, the identification of uridine 5′-diphosphoglucuronosyltransferase 2B10 as the catalyst of nicotine N-glucuronidation, are discussed. We also describe epidemiology studies that establish the contribution of nicotine metabolism and CYP2A6 genotype to lung cancer risk, particularly with respect to specific racial/ethnic groups, such as those with Japanese, African, or European ancestry. We conclude that a model of nicotine metabolism and smoking dose could be combined with other lung cancer risk variables to more accurately identify former smokers at the highest risk of lung cancer and to intervene accordingly.

Short-term whole body cigarette smoke exposure induces regional differences in cellular response in the mouse larynx

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Short-term CSE induced regional differences in murine laryngeal cellular responses.

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Basal cell hyperplasia accompanies adaptive cell proliferation in the vocal folds.

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Increased subglottic cell proliferation persists even after CS cessation.

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SEM revealed vocal fold microprojection damage with possible necrotic features.

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Subglandular acidic mucins decreased and neutral mucins increased post-CSE.

The larynx is an essential organ in the respiratory tract and necessary for airway protection, respiration, and phonation. Cigarette smoking is a significant risk factor associated with benign and malignant laryngeal diseases. Despite this association, the underlying mechanisms by which cigarette smoke (CS) drives disease development are not well elucidated. In the current study, we developed a short-term murine whole body inhalation model to evaluate the first CS-induced cellular responses in the glottic [i.e. vocal fold (VF)] and subglottic regions of the larynx. Specifically, we investigated epithelial cell proliferation, cell death, surface topography, and mucus production, at various time points (1 day, 5 days, 10 days) after ∼ 2 h exposure to 3R4F cigarettes (Delivered dose: 5.6968 mg/kg per cigarette) and following cessation for 5 days after a 5 day CS exposure (CSE). CSE elevated levels of BrdU labeled proliferative cells and p63 labeled epithelial basal cells on day 1 in the VF. CSE increased proliferative cells in the subglottis at days 5, 10 and following cessation in the subglottis. Cleaved caspase-3 apoptotic activity was absent in VF at all time points and increased at day 1 in the subglottis. Evaluation of the VF surface by scanning electron microscopy (SEM) revealed significant epithelial microprojection damage at day 10 and early signs of necrosis at days 5 and 10 post-CSE. SEM visualizations additionally indicated the presence of deformed cilia at days 5 and 10 after CSE and post-cessation in the respiratory epithelium lined subglottis. In terms of mucin content, the impact of short-term CSE was observed only at day 10, with decreasing acidic mucin levels and increasing neutral mucin levels. Overall, these findings reveal regional differences in murine laryngeal cellular responses following short-term CSE and provide insight into potential mechanisms underlying CS-induced laryngeal disease development.

Tobacco-Specific Nitrosamines (NNAL, NNN, NAT, and NAB) Exposures in the US Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

INTRODUCTION

The tobacco-specific nitrosamines (TSNAs) are an important group of carcinogens found in tobacco and tobacco smoke. To describe and characterize the levels of TSNAs in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014), we present four biomarkers of TSNA exposure: N'-nitrosonornicotine, N'-nitrosoanabasine, N'-nitrosoanatabine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) which is the primary urinary metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.

METHODS

We measured total TSNAs in 11 522 adults who provided urine using automated solid-phase extraction coupled to isotope dilution liquid chromatography-tandem mass spectrometry. After exclusions in this current analysis, we selected 11 004 NNAL results, 10 753 N'-nitrosonornicotine results, 10 919 N'-nitrosoanatabine results, and 10 996 N'-nitrosoanabasine results for data analysis. Geometric means and correlations were calculated using SAS and SUDAAN.

RESULTS

TSNA concentrations were associated with choice of tobacco product and frequency of use. Among established, every day, exclusive tobacco product users, the geometric mean urinary NNAL concentration was highest for smokeless tobacco users (993.3; 95% confidence interval [CI: 839.2, 1147.3] ng/g creatinine), followed by all types of combustible tobacco product users (285.4; 95% CI: [267.9, 303.0] ng/g creatinine), poly tobacco users (278.6; 95% CI: [254.9, 302.2] ng/g creatinine), and e-cigarette product users (6.3; 95% CI: [4.7, 7.9] ng/g creatinine). TSNA concentrations were higher in every day users than in intermittent users for all the tobacco product groups. Among single product users, exposure to TSNAs differed by sex, age, race/ethnicity, and education. Urinary TSNAs and nicotine metabolite biomarkers were also highly correlated.

CONCLUSIONS

We have provided PATH Study estimates of TSNA exposure among US adult users of a variety of tobacco products. These data can inform future tobacco product and human exposure evaluations and related regulatory activities.

Developmental Exposure to Air Pollution, Cigarettes, and Lead: Implications for Brain Aging

Brain development is impaired by maternal exposure to airborne toxins from ambient air pollution, cigarette smoke, and lead. Shared postnatal consequences include gray matter deficits and abnormal behaviors as well as elevated blood pressure. These unexpectedly broad convergences have implications for later life brain health because these same airborne toxins accelerate brain aging. Gene-environment interactions are shown for ApoE alleles that influence the risk of Alzheimer disease. The multigenerational trace of these toxins extends before fertilization because egg cells are formed in the grandmaternal uterus. The lineage and sex-specific effects of grandmaternal exposure to lead and cigarettes indicate epigenetic processes of relevance to future generations from our current and recent exposure to airborne toxins.

Public Understanding of Cigarette Smoke Chemicals: Longitudinal Study of US Adults and Adolescents

INTRODUCTION

The US Food and Drug Administration has increased communication efforts that aim to raise public awareness of the harmful constituents (ie, chemicals) in cigarette smoke. We sought to investigate whether the public's awareness of these chemicals has increased in light of such efforts.

METHODS

Participants were national probability samples of 11 322 US adults and adolescents recruited in 2014-2015 (wave 1) and 2016-2017 (wave 2). Cross-sectional telephone surveys assessed awareness of 24 cigarette smoke chemicals at both timepoints.

RESULTS

The proportion of US adults aware of cigarette smoke chemicals did not differ between waves 1 and 2 (25% and 26%, p = .19). In contrast, awareness of chemicals among adolescents fell from 28% to 22% (p < .001), mostly due to lower awareness of carbon monoxide, arsenic, benzene, and four other chemicals. Belief that most of the harmful chemicals in cigarette smoke come from burning the cigarette also fell from waves 1 to 2 (adults: 31% vs. 26%; adolescents: 47% vs. 41%, both ps < .05). Participants were more likely to be aware of cigarette smoke chemicals if they had been exposed to anti-smoking campaign advertisements (p < .05) or had previously sought chemical information (p < .05). Cigarette smoke chemical awareness did not differ between smokers and nonsmokers.

CONCLUSION

Awareness of cigarette smoke chemicals remains low and unchanged among adults and decreased somewhat among adolescents. The association of chemical awareness with information exposure via campaigns and information seeking behavior is promising. More concerted communication efforts may be needed to increase public awareness of cigarette smoke chemicals, which could potentially discourage smoking.

IMPLICATIONS

Awareness of the toxic chemicals in cigarette smoke may contribute to quitting. The US Food and Drug Administration is making efforts to increase public awareness of these chemicals. Two national surveys (2014-2017) found that chemical awareness was low among adults and adolescents. Although awareness did not change among adults, awareness among adolescents dropped over time. In addition, exposure to anti-smoking campaigns and chemical information seeking behavior were associated with higher awareness of chemicals in cigarette smoke. Campaigns and other efforts may be needed to increase awareness of cigarette smoke chemicals.

Multi-Omics Analysis to Characterize Cigarette Smoke Induced Molecular Alterations in Esophageal Cells

Though smoking remains one of the established risk factors of esophageal squamous cell carcinoma, there is limited data on molecular alterations associated with cigarette smoke exposure in esophageal cells. To investigate molecular alterations associated with chronic exposure to cigarette smoke, non-neoplastic human esophageal epithelial cells were treated with cigarette smoke condensate (CSC) for up to 8 months. Chronic treatment with CSC increased cell proliferation and invasive ability of non-neoplastic esophageal cells. Whole exome sequence analysis of CSC treated cells revealed several mutations and copy number variations. This included loss of high mobility group nucleosomal binding domain 2 (HMGN2) and a missense variant in mediator complex subunit 1 (MED1). Both these genes play an important role in DNA repair. Global proteomic and phosphoproteomic profiling of CSC treated cells lead to the identification of 38 differentially expressed and 171 differentially phosphorylated proteins. Bioinformatics analysis of differentially expressed proteins and phosphoproteins revealed that most of these proteins are associated with DNA damage response pathway. Proteomics data revealed decreased expression of HMGN2 and hypophosphorylation of MED1. Exogenous expression of HMGN2 and MED1 lead to decreased proliferative and invasive ability of smoke exposed cells. Immunohistochemical labeling of HMGN2 in primary ESCC tumor tissue sections (from smokers) showed no detectable expression while strong to moderate staining of HMGN2 was observed in normal esophageal tissues. Our data suggests that cigarette smoke perturbs expression of proteins associated with DNA damage response pathways which might play a vital role in development of ESCC.

Implementation of Recycling Cigarette Butts in Lightweight Bricks and a Proposal for Ending the Littering of Cigarette Butts in Our Cities

Our cities, parks, beaches, and oceans have been contaminated for many years with millions of tonnes of unsightly and toxic cigarette butts (CBs). This study presents and discusses some of the results of an ongoing study on recycling in fired-clay bricks. Energy savings: the energy value of CBs with remnant tobacco was found to be 16.5 MJ/kg. If just 2.5% of all bricks produced annually worldwide included 1% CB content, all of the CBs currently produced could be recycled in bricks, and it is estimated that global firing energy consumption could be reduced by approximately 20 billion MJ (megajoules). This approximately equates to the power used by one million homes in Victoria, Australia, every year. Bacteriological study: CBs were investigated for the presence of ten common bacteria in two pilot studies. Staphylococcus spp. and Pseudomonas aeruginosa were detected in fresh used CB samples, and Listeria spp. were detected in old used CB samples. All of the CB samples except the dried sample had significant counts of Bacillus spp. Some species of the detected bacteria in this study are pathogenic. Further confirmation and comprehensive microbiological study are needed in this area. The contact of naphthalene balls with CBs had a significant disinfecting effect on Bacillus spp. The implementation procedure for recycling CBs in bricks, odour from Volatile Organic Compound (VOC) emissions in CBs, sterilization methods, CB collection systems, and safety instructions were investigated, and they are discussed. Proposal: when considering the combined risks from many highly toxic chemicals and possible pathogens in cigarette butts, it is proposed that littering of this waste anywhere in cities and the environment be strictly prohibited and that offenders be heavily fined.

Association between Metabolites and the Risk of Lung Cancer: A Systematic Literature Review and Meta-Analysis of Observational Studies

Globally, lung cancer is the most prevalent cancer type. However, screening and early detection is challenging. Previous studies have identified metabolites as promising lung cancer biomarkers. This systematic literature review and meta-analysis aimed to identify metabolites associated with lung cancer risk in observational studies. The literature search was performed in PubMed and EMBASE databases, up to 31 December 2019, for observational studies on the association between metabolites and lung cancer risk. Heterogeneity was assessed using the I² statistic and Cochran’s Q test. Meta-analyses were performed using either a fixed-effects or random-effects model, depending on study heterogeneity. Fifty-three studies with 297 metabolites were included. Most identified metabolites (252 metabolites) were reported in individual studies. Meta-analyses were conducted on 45 metabolites. Five metabolites (cotinine, creatinine riboside, N-acetylneuraminic acid, proline and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene) and five metabolite groups (total 3-hydroxycotinine, total cotinine, total nicotine, total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (sum of concentrations of the metabolite and its glucuronides), and total nicotine equivalent (sum of total 3-hydroxycotinine, total cotinine and total nicotine)) were associated with higher lung cancer risk, while three others (folate, methionine and tryptophan) were associated with lower lung cancer risk. Significant heterogeneity was detected across most studies. These significant metabolites should be further evaluated as potential biomarkers for lung cancer.

Biomarkers of Tobacco Exposure Decrease After Smokers Switch to an E-Cigarette or Nicotine Gum

Introduction

The aerosol composition of electronic cigarettes (ECs) suggests that exposure to toxicants during use is greatly reduced compared to exposure from combustible cigarettes (CCs).

Methods

This randomized, parallel-group, clinical study enrolled smokers to switch to Vuse Solo (VS) Digital Vapor Cigarettes (Original or Menthol) or Nicorette 4 mg nicotine gum (NG) in a controlled setting. Subjects who smoked CCs ad libitum for 2 days during a baseline period were then randomized to ad libitum use of either VS or NG for 5 days. Biomarkers of 23 toxicants were measured in 24-hour urine samples and blood collected at baseline and following product switch.

Results

A total of 153 subjects completed the study. Total nicotine equivalents decreased in all groups, but higher levels were observed in the VS groups compared to the NG groups, with decreases of 38% and 60%–67%, respectively. All other biomarkers were significantly decreased in subjects switched to VS, and the magnitude of biomarker decreases was similar to subjects switched to NG. Decreases ranged from 30% to greater than 85% for constituents such as benzene and acrylonitrile.

Conclusions

These results indicate that exposure to toxicants when using VS is significantly reduced compared to CC smoking, and these reductions are similar to those observed with use of NG. Although statistically significantly decreased, nicotine exposure is maintained closer to CC smoking with VS use compared to NG use. This research suggests that use of VS exposes consumers to fewer and lower levels of smoke toxicants than CCs while still providing nicotine to the consumer.

Implications

This is the first study to report changes in nicotine delivery and biomarkers of tobacco exposure following a short-term product switch from CCs to either an EC or NG in a controlled environment. The study shows that nicotine exposure decreased in both groups but was maintained closer to CC smoking with the EC groups. Biomarkers of tobacco combustion decreased to similar levels in both EC and gum groups.

Passive Smoking Exposure in Living Environments Reduces Cognitive Function: A Prospective Cohort Study in Older Adults

There is currently no consensus regarding the effects of passive smoking exposure on cognitive function in older adults. We evaluated 7000 permanent residents from six regions within Zhejiang Province, China, aged ≥60 years, without cognitive impairment at baseline and during follow-up examinations for two years. The Chinese version of the Mini-Mental State Examination was used to assess the participants’ cognitive function. Multivariate regression analyses were carried out to calculate the adjusted relative risks (RRs) as measures of the association between passive smoking exposure and cognitive impairment after adjusting for potential confounders. The results showed an association between passive smoking exposure in the living environment and increased risk of cognitive impairment (RR: 1.16; 95% confidence interval (CI): 1.01–1.35). No dose–response relationship between the cumulative dose of passive smoking exposure (days) and cognitive impairment was observed. The results of stratified analyses suggested a harmful effect of passive smoking exposure on cognitive function in non-smokers (RR: 1.24; 95% CI: 1.06–1.46), but not in smokers (RR: 1.11; 95% CI: 0.71–1.92). Therefore, passive smoking exposure increased the risk of cognitive impairment in older adults, especially non-smokers. More effective measures to restrict smoking in the living environment should be developed and implemented.

An Unusual Occurrence of Multiple Metachronous and Synchronous Primary Cancers in a Female Patient

Multiple primary cancers, although uncommon, have been increasing in incidence in recent years. This trend is likely due to advances in factors such as diagnostic imaging, life expectancy, and interventional modalities with associated adverse effects. The patient presented in this case report is a 59-year-old Caucasian female with an extensive medical history who developed multiple primary cancers of the breast, mouth, gastrointestinal system, and lung in the span of four years. We attempted to elucidate the possible etiologies and risk factors that may have contributed. Given the patient's complex medical and social history, interventions, environmental, and genetic predispositions, it is impossible to pinpoint a single etiology. Rather, it is more likely that the interplay of multiple factors contributed to the findings of this case.

Replication of Pyridyloxobutyl Phosphotriester Lesions in Cells

Genome integrity is constantly challenged by endogenous or exogenous genotoxic agents, which can give rise to various DNA adducts. After metabolic activation, tobacco-specific nitrosamines N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) can lead to pyridyloxobutylphosphotriesters (POB-PTEs) in DNA. Here, we synthesized oligodeoxyribonucleotides containing a site-specifically inserted S_P- or R_P-POB-PTE flanked by two thymidines, and we examined the impact that these lesions have on DNA replication in Escherichia coli cells. We found that these two lesions are not strong impediments to DNA replication, and their replicative bypass is not modulated by genetic depletion of the three SOS-induced DNA polymerases or Ada protein. In addition, neither S_P- nor R_P-POB-PTEs was mutagenic in E. coli cells. Together, our study unveiled, for the first time, the influence of tobacco-specific nitrosamine-induced POB-PTE lesions on DNA replication in vivo.

Evaluation of Tobacco Smoke and Diet as Sources of Exposure to Two Heterocyclic Aromatic Amines for the U.S. Population: NHANES 2013-2014

BACKGROUND

Heterocyclic aromatic amines (HAA) are a group of hazardous substances produced during combustion of tobacco or high-temperature cooking of meats. 2-Amino-9H-pyrido[2,3-b]indole (AαC) is a major carcinogenic HAA in tobacco smoke.

METHODS

Urinary AαC, used as a marker of AαC exposure, was analyzed on spot urine samples from adult participants of the 2013-2014 cycle of the National Health and Nutrition Examination Survey (N = 1,792). AαC was measured using isotope-dilution liquid chromatography-tandem mass spectrometry. Exclusive combusted tobacco smokers were differentiated from nonusers of tobacco products through both self-report and serum cotinine data.

RESULTS

Among exclusive smokers, sample-weighted median urinary AαC was 40 times higher than nonusers. Sample-weighted regression models showed that urinary AαC increased significantly with serum cotinine among both exclusive tobacco users and nonusers with secondhand smoke exposure. Among nonusers, eating beef cooked at high temperature was associated with a significant increase in urinary AαC, whereas consuming vegetables was associated with decreased AαC. In addition, smoking one-half pack of cigarettes per day was associated with a significant increase of 23.6 pg AαC/mL calculated at geometric mean of AαC, controlling for potential confounders. In comparison, increase in AαC attributable to consuming the 99th percentile of beef cooked at high temperature was 0.99 pg AαC/mL.

CONCLUSIONS

Both exclusive smokers and nonusers of tobacco in the general U.S. population are exposed to AαC from tobacco smoke, with additional, lesser contributions from certain dietary components.

IMPACT

AαC is an important biomarker that is associated with tobacco smoke exposure.

Oral Health Effects of Combusted and Smokeless Tobacco Products

The oral cavity is usually the first part of a consumer's body exposed to the constituents of tobacco products or their emissions. Consequently, the oral cavity is a frequent site for carcinogenic, microbial, immunologic, and clinical effects of tobacco use. This article summarizes 5 presentations on various aspects of oral health affected by combusted or noncombusted tobacco products from a recent conference, "Oral Health Effects of Tobacco Products: Science and Regulatory Policy," sponsored by the American Association for Dental Research and the Food and Drug Administration.

Genotoxic effects of tobacco use in residents of hilly areas and foot hills of Western Ghats, Southern India

Smoking and smokeless tobacco consumption is a significant risk factor that provokes genetic alterations. The present investigation was to evaluate the biomarkers of genotoxicity including micronucleus (MN), chromosome aberrations (CA) and DNA strand breaks among tobacco consumers and control individuals residing in hilly areas of Western Ghats, Tamilnadu, South India. This study included 268 tobacco consumers with equal number of controls. The tobacco consumers were divided into Group I (<10 years of tobacco consumption with an age range from 15 to 35 years) and group II (>10 years consumption above 35 years of age). Chromosome aberration (CA) and comet assay were performed using blood and micronucleus assay from exfoliated buccal epithelial cells obtained from tobacco consumers and controls. Elevated levels of CA were found in group II (Chromatid type: 2.39 ± 1.13 and chromosome type: 1.44 ± 1.24) exposed subjects, high micronucleus and DNA damage (TL:4.48 ± 1.24 and TM:3.40 ± 1.58) levels were significantly (p < 0.05) observed in both smoking and smokeless tobacco consumers when comparison with group I and controls. This study also observed a lack of awareness among the tobacco consumers about the harmful health effects of tobacco. Tobacco consumption contributes to the significant alteration in genetic materials. In addition, a high rate of spontaneous abortion was also seen in the studied population.

Cytotoxicity of aqueous cigarette smoke extract is affected by properties of pipettes used to prepare the extract

Cigarette smoke contains a host of molecules including toxins and carcinogens, most of which have not been well studied. Aqueous cigarette smoke extract (CSE) is one of various cigarette smoke derivatives that can be used for in vitro studies, and the influence of different method parameters on CSE composition and toxicity remains incompletely understood. Herein, we prepared CSE by bubbling cigarette smoke through mammalian cell culture medium, varying the type of pipette inserted into the recipient medium. Changing this one component of the preparation apparatus had a marked effect on the toxicity of the resulting CSE. Since many other parameters can also be varied in CSE preparation, these results stress the importance of standardization within and between studies.

ADAM17: An Emerging Therapeutic Target for Lung Cancer

Lung cancer is the leading cause of cancer-related mortality, which histologically is classified into small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC accounts for approximately 85% of all lung cancer diagnoses, with the majority of patients presenting with lung adenocarcinoma (LAC). KRAS mutations are a major driver of LAC, and are closely related to cigarette smoking, unlike mutations in the epidermal growth factor receptor (EGFR) which arise in never-smokers. Although the past two decades have seen fundamental progress in the treatment and diagnosis of NSCLC, NSCLC still is predominantly diagnosed at an advanced stage when therapeutic interventions are mostly palliative. A disintegrin and metalloproteinase 17 (ADAM17), also known as tumour necrosis factor-α (TNFα)-converting enzyme (TACE), is responsible for the protease-driven shedding of more than 70 membrane-tethered cytokines, growth factors and cell surface receptors. Among these, the soluble interleukin-6 receptor (sIL-6R), which drives pro-inflammatory and pro-tumourigenic IL-6 trans-signaling, along with several EGFR family ligands, are the best characterised. This large repertoire of substrates processed by ADAM17 places it as a pivotal orchestrator of a myriad of physiological and pathological processes associated with the initiation and/or progression of cancer, such as cell proliferation, survival, regeneration, differentiation and inflammation. In this review, we discuss recent research implicating ADAM17 as a key player in the development of LAC, and highlight the potential of ADAM17 inhibition as a promising therapeutic strategy to tackle this deadly malignancy.

Physical binding of the tobacco smoke carcinogen NNK diazonium ion to the human tumor suppressor gene TP53 Exon 5

The tobacco smoke N-nitrosamine, NNK, is an important carcinogen. It has been shown to induce lung, liver, and pancreatic cancer in animals. Its metabolites are associated with lung cancer in tobacco smokers. Our work focuses upon the physical interaction of NNK diazonium ion with DNA. This species is implicated in the formation of pyridyloxobutyl adducts, reacting with DNA bases and phosphate groups. Past research has investigated the metabolic activation of NNK by various enzymes, subsequent adduct formation with DNA, and the role of these adducts in mutagenesis. We present the first study of the physical interaction of NNK diazonium ion with TP53 (exon 5), a frequently mutated human tumor suppressor gene. We identify physical binding sites found via free energy minimization in computational docking simulations. These structures represent local potential energy minima in this system and suggest plausible sites for adduct formation.

Analysis of Acrolein-Derived 1, N2-Propanodeoxyguanosine Adducts in Human Lung DNA from Smokers and Nonsmokers

Acrolein, the simplest α,β-unsaturated aldehyde, is present in relatively large quantities in cigarette smoke, and several studies have raised the possibility of it being a major etiological agent for smoking-related lung cancer. Acrolein reacts directly with DNA to form primarily Acr-dGuo adducts, which serve as important biomarkers for the assessment of exposure to acrolein and its potential role in smoking-related lung cancer. In this study, we developed an ultrasensitive and low-artifact method using liquid chromatography-nanoelectrospray ionization-high-resolution tandem mass spectrometry to quantitate Acr-dGuo adducts in normal lung tissue DNA obtained at surgery from lung cancer patients who never smoked and from those who continued smoking until surgery, as confirmed by urinary total cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol. This provides a direct comparison of Acr-dGuo levels in human lung tissue as a result of cigarette smoking versus other etiological causes. There was no significant difference between the total Acr-dGuo levels in smokers (28.5 ± 14.9 adducts/109 nucleotides) and nonsmokers (25.0 ± 10.7 adducts/109 nucleotides), suggesting rapid removal of acrolein by glutathione conjugation and other detoxification mechanisms. Our results do not support the hypothesis that acrolein is a major etiological agent for cigarette smoking-related DNA damage.

Urinary Biomarkers of Carcinogenic Exposure among Cigarette, Waterpipe, and Smokeless Tobacco Users and Never Users of Tobacco in the Golestan Cohort Study

BACKGROUND

How carcinogen exposure varies across users of different, particularly noncigarette, tobacco products remains poorly understood.

METHODS

We randomly selected 165 participants of the Golestan Cohort Study from northeastern Iran: 60 never users of any tobacco, 35 exclusive cigarette, 40 exclusive (78% daily) waterpipe, and 30 exclusive smokeless tobacco (nass) users. We measured concentrations of 39 biomarkers of exposure in 4 chemical classes in baseline urine samples: tobacco alkaloids, tobacco-specific nitrosamines (TSNA), polycyclic aromatic hydrocarbons (PAH), and volatile organic compounds (VOC). We also quantified the same biomarkers in a second urine sample, obtained 5 years later, among continuing cigarette smokers and never tobacco users.

RESULTS

Nass users had the highest concentrations of tobacco alkaloids. All tobacco users had elevated TSNA concentrations, which correlated with nicotine dose. In both cigarette and waterpipe smokers, PAH and VOC biomarkers were higher than never tobacco users and nass users, and highly correlated with nicotine dose. PAH biomarkers of phenanthrene and pyrene and two VOC metabolites (phenylmercapturic acid and phenylglyoxylic acid) were higher in waterpipe smokers than in all other groups. PAH biomarkers among Golestan never tobacco users were comparable to those in U.S. cigarette smokers. All biomarkers had moderate to good correlations over 5 years, particularly in continuing cigarette smokers.

CONCLUSIONS

We observed two patterns of exposure biomarkers that differentiated the use of the combustible products (cigarettes and waterpipe) from the smokeless product. Environmental exposure from nontobacco sources appeared to contribute to the presence of high levels of PAH metabolites in the Golestan Cohort.

IMPACT

Most of these biomarkers would be useful for exposure assessment in a longitudinal study.

Finding Pete and Nikki: Defining the Target Audience for "The Real Cost" Campaign

Successfully reaching at-risk teens aged 12-17 years with smoking-prevention messages capable of changing their knowledge, attitudes, and beliefs about cigarette smoking requires a multifaceted approach to understand the target audience's unique demographic, environmental, behavioral, interpersonal, and intrapersonal characteristics. This paper explores the initial target audience segmentation and insights development approach used to create the underlying message strategy for "The Real Cost" youth smoking prevention media campaign-a public education effort responsible for preventing nearly 350,000 U.S. youth aged 11-18 years from initiating smoking from 2014 to 2016. SUPPLEMENT INFORMATION: This article is part of a supplement entitled Fifth Anniversary Retrospective of "The Real Cost," the Food and Drug Administration's Historic Youth Smoking Prevention Media Campaign, which is sponsored by the U.S. Food and Drug Administration.

Electronic nicotine delivery systems: Oral health implications and oral cancer risk

There is a paucity of evidence surrounding the potential detrimental effects of electronic nicotine delivery systems (ENDS) for both systemic and oral health. The effects of conventional cigarettes on the development of oral cancer are well known; however, the role of ENDS in oral carcinogenesis is yet to be elucidated. Furthermore, the exponential rise of the use of ENDS by the general public means that dental healthcare providers are more likely to encounter questions on their safety in the oral cavity, and on their effectiveness as a smoking cessation aid. Herein, we review the most up to date literature on the systemic and oral health complications of ENDS. Moreover, evidence-based recommendations on the use of ENDS as a smoking cessation tool within the dental setting are discussed.

Urine 4-(methylnitrosamino)-1-(3) pyridyl-1-butanol and cotinine in Alaska native postpartum women and neonates comparing smokers and smokeless tobacco users

OBJECTIVE

Foetuses and neonates of women who use tobacco are exposed to nicotine and tobacco-derived carcinogens. We determined the relationship between urine biomarkers of tobacco toxicant exposure postpartum and in the neonates of Alaska Native (AN) women, comparing smokers and smokeless tobacco (ST) users, including iqmik, a homemade ST product.

METHODS

AN women, including 36 smokers, 9 commercial ST and 16 iqmik users their neonates participated. Urine from the woman at the time of delivery and her neonate's first urine were analysed for cotinine, the major metabolite of nicotine, and 4-(methylnitrosamino)-1-(3) pyridyl-1-butanol (NNAL), a tobacco-specific carcinogen biomarker.

RESULTS

Maternal urine cotinine and neonatal urine cotinine were strongly correlated in all tobacco use groups (r from 0.83 to 0.9, p < 0.002). Correlations between maternal cotinine and neonatal NNAL were moderately strong for cigarettes and commercial smokeless but weaker for iqmik users (r 0.73, 0.6 and 0.36, respectively).

CONCLUSION

Correlations between maternal and neonatal biomarkers of tobacco toxicant exposure vary, dependent on tobacco product use.

SIGNIFICANCE

This study provides novel data on biomarkers of tobacco exposure among postpartum AN women and their neonates. The results could be useful to guide future epidemiological studies of health risks associated with use of various tobacco products during pregnancy.

Heated tobacco products likely appeal to adolescents and young adults

BACKGROUND

Beginning in the 1960s in the USA and globally since 1998, tobacco companies have beenaggressively promoting heated tobacco products (HTP). In 2016, Philip Morris International (PMI) applied to the US Food and Drug Administration (FDA) seeking authorisation to market their IQOS HTP system and flavoured 'HeatSticks' in the USA as a modified-risk tobacco product (MRTP).

METHODS

We systematically evaluated the publicly available data PMI submitted to FDA in its MRTP application to determine whether PMI's IQOS product meets the US Tobacco Control Act's standard for MRTP claims. We examined whether PMI provided sufficient data showing tobacco users will not initiate with IQOS, that youth will not misperceive the MRTP-related claims being made concerning IQOS, and how youth perceive health risks associated with IQOS.

RESULTS

PMI's own studies failed to provide evidence that youth, including non-users and former users, will not find IQOS appealing, will not initiate use of IQOS and will not perceive these products as risk-free. Further, PMI did not refer to independent studies conducted among adolescents which could influence their conclusions. Finally, their studies suffered from design and implementation flaws and cannot be relied on to support the proffered claims.

CONCLUSION

PMI's own data and available evidence from scientific studies conducted independent of the tobacco industry regarding how novel tobacco products are currently being marketed suggest that introduction of IQOS will result in adolescent and young adult non-users initiating tobacco use with IQOS and could also increase poly-use of IQOS along with other tobacco products.

Relationship of the oxidative damage biomarker 8-epi-prostaglandin F2α to risk of lung cancer development in the Shanghai Cohort Study

It has been hypothesized that the pathogenesis of lung cancer induced by cigarette smoking involves oxidative damage by free radicals. Epidemiological data on biomarkers of oxidative damage and risk of lung cancer development are sparse. A nested case-control study of 610 lung cancer cases and 610 matched controls was conducted within a prospective cohort of 18 244 Chinese men in Shanghai, China. The concentrations of 8-epi-prostaglandin F2α (8-epiPGF2α), a biomarker of oxidative stress, were determined in baseline urine samples using a validated mass-spectrometry assay. Current smokers had significantly higher level of 8-epiPGF2α than former smokers or never smokers (P < 0.001). 8-epiPGF2α levels were significantly higher in lung cancer cases than their smoking-matched controls in former and current smokers, but not different in never smokers (P for interaction = 0.019). The relative risks of developing lung cancer for former and current smokers in the highest relative to the lowest quartile of 8-epiPGF2α were 5.25 (Ptrend = 0.035) and 1.99 (Ptrend =0.007), respectively. The effect of 8-epiPGF2α and biomarkers of cigarette smoke exposure on lung cancer risk was additive; the relative risk was 5.33 (95% confidence interval = 2.65-7.51) for current smokers with the highest thirds of 8-epiPGF2α and total cotinine compared with their lowest thirds. Smokers with a heightened state of oxidative stress in response to the insults of cigarette smoking may be more susceptible to smoking-induced lung carcinogenesis.

Glutathione and Inter-α-trypsin inhibitor heavy chain 3 (Itih3) mRNA levels in nicotine-treated Cd44 knockout mice

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Chronic nicotine use that replaces tobacco smoking weakens antioxidant defense.

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Depletion of glutathione by chronic nicotine delivery may compromise liver health.

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Inter-α-trypsin Inhibitor Heavy Chain 3 (Itih3) mRNA correlates with glutathione.

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Nicotine and sex interact with Cd44 signaling in regulation of liver glutathione.

Cluster of differentiation 44 (Cd44), a hyaluronan receptor, and the secreted hyaluronan-binding protein Inter-α-trypsin Inhibitor Heavy chain 3 (Itih3) play an important role in cancer and oxidative stress. Smoking of tobacco reduces Itih3 in the plasma and activates hyaluronan signaling through Cd44, but the impact of Cd44 on Itih3 expression is unknown. Here, we studied changes induced by the tobacco component nicotine on the glutathione (GSH) antioxidant system and Itih3 gene expression in Cd44 knockout mice. Cd44 deficiency decreased baseline total GSH and oxidized glutathione (GSSG) levels in the liver compared to wildtype mice. However, contrary to wildtype mice, chronic oral nicotine administration (200 μg/ml) failed to further reduce total GSH and GSSG in Cd44 mice. Sex differences with lowered glutathione levels in females was also detectable only in wildtype but not Cd44 knockout mice. Itih3 mRNA levels in the liver and hypothalamus were not affected by nicotine, Cd44 genotype or sex. Nonetheless, the correlation between Itih3 and total GSH levels in the liver (r = 0.42, p < 0.05) suggested a role of Itih3 in glutathione metabolism in WT mice. Again this effect was diminished in Cd44 knockout mice. The disappearance of nicotine effects, sex differences and correlations between Itih3 and total GSH in Cd44 knockout mice compared to wildtype animals suggests an interaction between nicotine, Cd44 and/or sex-dependent signaling in the regulation of glutathione metabolism.

Cigarette Filter Ventilation and Smoking Protocol Influence Aldehyde Smoke Yields

The WHO study group on tobacco product regulation (TobReg) advised regulating and lowering toxicant levels in cigarette smoke. Aldehydes are one of the chemical classes on the TobReg smoke toxicants priority list. To provide insight in factors determining aldehyde yields, the levels of 12 aldehydes in mainstream cigarette smoke of 11 Dutch brands were quantified. Variations in smoking behavior and cigarette design affecting human exposure to aldehydes were studied by using four different machine testing protocols. Machine smoking was based on the International Standardization Organization (ISO) and Health Canada Intense (HCI) regime, both with and without taping the filter vents. The 11 cigarette brands differed in (i) design and blend characteristics; (ii) tar, nicotine, and carbon monoxide (TNCO) levels; (iii) popularity; and (iv) manufacturer. Cigarette smoke was trapped on a Cambridge filter pad and carboxen cartridge. After being dissolved in methanol/CS2 and derivatization with DNPH, the aldehyde yields were determined using HPLC-DAD. Using an intense smoking regime (increased puff volume, shorter puff interval) significantly increased aldehyde yields, following the pattern: ISO < ISO-taped < HCI-untaped < HCI. For all of the regimes, acetaldehyde and acrolein yields were strongly correlated ( r = 0.804). The difference in TNCO and aldehyde levels between regular and highly ventilated low-TNCO cigarettes (as measured using ISO) diminished when smoking intensely; this effect is stronger when combined with taping filter vents. The highly ventilated low-TNCO brands showed six times more aldehyde production per mg nicotine for the intense smoking regimes. In conclusion, acetaldehyde and acrolein can be used as representatives for the class of volatile aldehydes for the different brands and smoking regimes. The aldehyde-to-nicotine ratio increased when highly ventilated cigarettes were smoked intensely, similar to real smokers. Thus, a smoker of highly ventilated low-TNCO cigarettes has an increased potential for higher aldehyde exposures compared to a smoker of regular cigarettes.

Influence of Smoking Puff Parameters and Tobacco Varieties on Free Radicals Yields in Cigarette Mainstream Smoke

Cigarette smoke is a major exogenous source of free radicals, and the resulting oxidative stress is one of the major causes of smoking-caused diseases. Yet, many of the factors that impact free radical delivery from cigarettes remain unclear. In this study, we machine-smoked cigarettes and measured the levels of gas- and particulate-phase radicals by electron paramagnetic resonance (EPR) spectroscopy using standardized smoking regimens (International Organization of Standardization (ISO) and Canadian Intense (CI)), puffing parameters, and tobacco blends. Radical delivery per cigarette was significantly greater in both gas (4-fold) and particulate (6-fold) phases when cigarettes were smoked under the CI protocol compared to the ISO protocol. Total puff volume per cigarette was the major factor with radical production being proportional to total volume, regardless of whether volume differences were achieved by changes in individual puff volume or puff frequency. Changing puff shape (bell vs sharp vs square) or puff duration (1-5 s), without changing volume, had no effect on radical yields. Tobacco variety did have a significant impact on free radical production, with gas-phase radicals highest in reconstituted > burley > oriental > bright tobacco and particulate-phase radicals highest in burley > bright > oriental > reconstituted tobacco. Our findings show that modifiable cigarette design features and measurable user smoking behaviors are key factors determining free radical exposure in smokers.

Cigarette pack messages about toxic chemicals: a randomised clinical trial

Background

The USA can require tobacco companies to disclose information about harmful and potentially harmful chemicals in cigarette smoke, but the impact of these messages is uncertain. We sought to assess the effect of placing messages about toxic chemicals on smokers’ cigarette packs.

Methods

Participants were 719 adult cigarette smokers from California, USA, recruited from September 2016 through March 2017. We randomly assigned smokers to receive either factual messages about chemicals in cigarette smoke and their health harms (intervention) or messages about not littering cigarette butts (control) on the side of their cigarette packs for 3 weeks. The primary trial outcome was intention to quit smoking.

Results

In intent-to-treat analyses, smokers whose packs had chemical messages did not have higher intentions to quit smoking at the end of the trial than those whose packs had control messages (P=0.56). Compared with control messages, chemical messages led to higher awareness of the chemicals (28% vs 15%, P<0.001) and health harms (60% vs 52%, P=0.02) featured in the messages. In addition, chemical messages led to greater negative affect, thinking about the chemicals in cigarettes and the harms of smoking, conversations about the messages and forgoing a cigarette (all P<0.05).

Discussion

Chemical messages on cigarette packs did not lead to higher intentions to quit among smokers in our trial. However, chemical messages informed smokers of chemicals in cigarettes and harms of smoking, which directly supports their implementation and would be critical to defending the messages against cigarette company legal challenges.

Trial registration number

NCT02785484.

Cigarette Smoking Impairs Adipose Stromal Cell Vasculogenic Activity and Abrogates Potency to Ameliorate Ischemia

Cigarette smoking (CS) adversely affects the physiologic function of endothelial progenitor, hematopoietic stem and progenitor cells. However, the effect of CS on the ability of adipose stem/stromal cells (ASC) to promote vasculogenesis and rescue perfusion in the context of ischemia is unknown. To evaluate this, ASC from nonsmokers (nCS-ASC) and smokers (CS-ASC), and their activity to promote perfusion in hindlimb ischemia models, as well as endothelial cell (EC) survival and vascular morphogenesis in vitro were assessed. While nCS-ASC improved perfusion in ischemic limbs, CS-ASC completely lost this therapeutic effect. In vitro vasculogenesis assays revealed that human CS-ASC and ASC from CS-exposed mice showed compromised support of EC morphogenesis into vascular tubes, and the CS-ASC secretome was less potent in supporting EC survival/proliferation. Comparative secretome analysis revealed that CS-ASC produced lower amounts of hepatocyte growth factor (HGF) and stromal cell-derived growth factor 1 (SDF-1). Conversely, CS-ASC secreted the angiostatic/pro-inflammatory factor Activin A, which was not detected in nCS-ASC conditioned media (CM). Furthermore, higher Activin A levels were measured in EC/CS-ASC cocultures than in EC/nCS-ASC cocultures. CS-ASC also responded to inflammatory cytokines with 5.2-fold increase in Activin A secretion, whereas nCS-ASC showed minimal Activin A induction. Supplementation of EC/CS-ASC cocultures with nCS-ASC CM or with recombinant vascular endothelial growth factor, HGF, or SDF-1 did not rescue vasculogenesis, whereas inhibition of Activin A expression or activity improved network formation up to the level found in EC/nCS-ASC cocultures. In conclusion, ASC of CS individuals manifest compromised in vitro vasculogenic activity as well as in vivo therapeutic activity. Stem Cells 2018;36:856-867.