Cytotoxic effects of heated tobacco products (HTP) on human bronchial epithelial cells

Toxicity of electronic cigarettes: A general review of the origins, health hazards, and toxicity mechanisms

Electronic cigarettes (E-cigarette) are an alternative for traditional cigarette smokers to quit smoking. Based on the current understanding, electronic cigarettes have rapidly become popular among existing smokers and former non-smokers. However, increasing research at different levels reveals that e-cigarettes are unsafe. This review provides an overview of the toxicology of e-cigarettes based on existing in vivo and in vitro studies and compares their toxicity with that of traditional cigarettes. Moreover, we describe the associated toxicity components in e-cigarettes, as well as the potential mechanism by which e-cigarettes exert toxic effects. As is known to all, the nicotine in traditional cigarettes and e-cigarettes has certain toxicity. Besides, a few studies have shown that propylene glycol and vegetable glycerin mixture and flavoring agents in e-cigarettes also are the key components causing adverse effects in animals or cells. There is insufficient scientific evidence on the toxicity of e-cigarettes due to the lack of standardized research methods, prompting the need to conduct a comprehensive toxicity assessment of e-cigarette toxicity to elucidate the safety issues of e-cigarettes. Eventually, a basis for decision-making on whether people use e-cigarettes will be obtained.

The development of an in vitro 3D model of goblet cell hyperplasia using MUC5AC expression and repeated whole aerosol exposures

Goblet cell hyperplasia and overproduction of airway mucin are characteristic features of the lung epithelium of smokers and COPD patients. Tobacco heating products (THPs) are a potentially less risky alternative to combustible cigarettes, and through continued use solus THPs may reduce smoking-related disease risk. Using the MucilAir™ in vitro lung model, a 6-week feasibility study was conducted investigating the effect of repeated cigarette smoke (1R6F), THP aerosol and air exposure. Tissues were exposed to nicotine-matched whole aerosol doses 3 times/week. Endpoints assessed were dosimetry, tight-junction integrity, cilia beat frequency (CBF) and active area (AA), cytokine secretion and airway mucin MUC5AC expression. Comparison of incubator and air exposed controls indicated exposures did not have a significant effect on the transepithelial electrical resistance (TEER), CBF and AA of the tissues. Cytokine secretion indicated clear differences in secretion patterns in response to 1R6F and THP exposure. 1R6F exposure resulted in a significant decrease in the TEER and AA (p=0.000 and p=0.000, respectively), and an increase in MUC5AC positive cells (p=0.002). Repeated THP exposure did not result in a significant change in MUC5AC positive cells. This study demonstrates repeated cigarette smoke whole aerosol exposure can induce these morphological changes in vitro.

Combustible cigarettes, heated tobacco products, combined product use, and periodontal disease: A cross-sectional JASTIS study

BACKGROUND

Combustible cigarettes have detrimental effects on periodontal disease. However, little evidence is available regarding new heated tobacco product (HTP) use and combined product use (both combustible cigarettes and HTPs). This study aimed to examine the association of combustible cigarettes, HTPs, and combined product use with periodontal disease simultaneously.

MATERIALS AND METHODS

This cross-sectional study was conducted using data from the 2019 arm of the longitudinal Japan "Society and New Tobacco" Internet Survey. Combustible cigarette users, HTP users, combined product users, never-users, and former users' data were separately obtained. In the present study, the primary outcome was self-reported periodontal disease. We estimated adjusted prevalence ratios (PRs) and confidence intervals (CIs) using multivariable modified Poisson regression analysis after adjusting for 12 confounders.

RESULTS

Of the 10,439 JASTIS respondents, the numbers of users of combustible cigarettes only, HTPs only, and both products were 1,304, 437, and 1,049, respectively. Compared with never-users, HTP use was significantly associated with the prevalence of self-reported periodontal diseases (PR 1.43, 95% CI 1.03-1.62). Moreover, former users, combustible cigarette users, and combined product users also showed significant associations (PR 1.56, 95% CI 1.35-1.80; PR 1.29, 95% CI 1.03-1.62; and PR 1.55, 95% CI 1.20-1.99, respectively).

CONCLUSIONS

Users of HTPs, combustible cigarettes, and combined products as well as former users were all significantly associated with a higher prevalence of periodontal diseases compared to never-users.

Cigarette smoke extract induces pyroptosis in human bronchial epithelial cells through the ROS/NLRP3/caspase-1 pathway

AIMS

Pyroptosis and inflammation are involved in the development of chronic obstructive pulmonary disease (COPD). However, the cigarette smoke-mediated mechanism of COPD remains unclear. In this study, we aimed to investigate the role of nucleotide-binding domain-like receptor protein-3 (NLRP3) inflammasome-mediated pyroptosis in the death of human bronchial epithelial (HBE) cells after cigarette smoke extract (CSE) exposure.

MAIN METHODS

The protein level of NLRP3 in lung tissue was measured after cigarette smoke exposure in vivo. In vitro, HBE cells were treated with CSE. Subsequently, the activity of caspase-1, lactate dehydrogenase (LDH) release, release of interleukin (IL)-1β and NLRP3 expression levels were measured. The involvement of reactive oxygen species (ROS) was also explored.

KEY FINDINGS

After exposure to CSE, increased release of LDH, the transcriptional and translational upregulation of NLRP3, the caspase-1 activity levels, and enhanced IL-1β and IL-18 release were observed in 16HBE cells. In addition, NLRP3 was required to activate the caspase-1. Our results suggested that pre-stimulated of 16HBE with a caspase-1 inhibitor, or using NLRP3 siRNA to silence NLRP3 expression, also caused the decrease of IL-1β release and pyroptosis.

SIGNIFICANCES

CSE induced inflammation and contributed to pyroptosis through the ROS/NLRP3/caspase-1 pathway in 16HBE cells. The NLRP3 inflammasome participates in CSE-induced HBE cell damage and pyroptosis, which could provide new insights into COPD.

Exploring in vitro to in vivo extrapolation for exposure and health impacts of e-cigarette flavor mixtures

In vitro to in vivo extrapolation (IVIVE) leverages in vitro biological activities to predict corresponding in vivo exposures, therefore potentially reducing the need for animal safety testing that are traditionally performed to support the hazard and risk assessment. Interpretation of IVIVE predictions are affected by various factors including the model type, exposure route and kinetic assumptions for the test article, and choice of in vitro assay(s) that are relevant to clinical outcomes. Exposure scenarios are further complicated for mixtures where the in vitro activity may stem from one or more components in the mixture. In this study, we used electronic cigarette (EC) aerosols, a complex mixture, to explore impacts of these factors on the use of IVIVE in hazard identification, using open-source pharmacokinetic models of varying complexity and publicly available data. Results suggest in vitro assay selection has a greater impact on exposure estimates than modeling approaches. Using cytotoxicity assays, high exposure estimates (>1000 EC cartridges (pods) or > 700 mL EC liquid per day) would be needed to obtain the in vivo plasma levels that are corresponding to in vitro assay data, suggesting acute toxicity would be unlikely in typical usage scenarios. When mechanistic (Tox21) assays were used, the exposure estimates were much lower for the low end, but the range of exposure estimate became wider across modeling approaches. These proof-of-concept results highlight challenges and complexities in IVIVE for mixtures.

Comparison of the chemical composition of aerosols from heated tobacco products, electronic cigarettes and tobacco cigarettes and their toxic impacts on the human bronchial epithelial BEAS-2B cells

The electronic cigarettes (e-cigs) and more recently the heated tobacco products (HTP) provide alternatives for smokers as they are generally perceived to be less harmful than conventional cigarettes. However, it is crucial to compare the health risks of these different emergent devices, in order to determine which product should be preferred to substitute cigarette. The present study aimed to compare the composition of emissions from HTP, e-cigs and conventional cigarettes, regarding selected harmful or potentially harmful compounds, and their toxic impacts on the human bronchial epithelial BEAS-2B cells. The HTP emitted less polycyclic aromatic hydrocarbons and carbonyls than the conventional cigarette. However, amounts of these compounds in HTP aerosols were still higher than in e-cig vapours. Concordantly, HTP aerosol showed reduced cytotoxicity compared to cigarette smoke but higher than e-cig vapours. HTP and e-cig had the potential to increase oxidative stress and inflammatory response, in a manner similar to that of cigarette smoke, but after more intensive exposures. In addition, increasing e-cig power impacted levels of certain toxic compounds and related oxidative stress. This study provides important data necessary for risk assessment by demonstrating that HTP might be less harmful than tobacco cigarette but considerably more harmful than e-cig.

E-cigarette aerosol induced cytotoxicity, DNA damages and late apoptosis in dynamically exposed A549 cells

In this study, the acute toxicological impacts associated with electronic cigarettes consumption were determined using a novel dynamic exposure methodology. The methodology was deployed to test various e-cigarette generated aerosols in A549 cell cultures. The e-liquid chemical profiling was achieved using GC-MS analysis while toxicity of diluted e-liquids aerosols was reported using numerous cytotoxicity assays. The presented findings pointed to acute aerosol exposure (thirty puffs at 40 W of power and higher) inducing significant cytotoxic, genotoxic, and apoptotic induction in exposed cells. These findings highlighted the significant risks posed by e-cigarette usage. The proposed methodology proved to be a useful tool for future screening of e-liquids generated aerosols toxicity. Future research is needed to establish the chronic toxicity resulting from long-term e-cigarette consumption.

Immunotoxic mechanisms of cigarette smoke and heat-not-burn tobacco vapor on Jurkat T cell functions

Cigarette smoke (CS) affects immune functions, leading to severe outcomes in smokers. Robust evidence addresses the immunotoxic effects of combustible tobacco products. As heat-not-burn tobacco products (HNBT) vaporize lower levels of combustible products, we here compared the effects of cigarette smoke (CS) and HNBT vapor on Jurkat T cells. Cells were exposed to air, conventional cigarettes or heatsticks of HNBT for 30 min and were stimulated or not with phorbol myristate acetate (PMA). Cell viability, proliferation, reactive oxygen species (ROS) production, 8-OHdG, MAP-kinases and nuclear factor κB (NFκB) activation and metallothionein expression (MTs) were assessed by flow cytometry; nitric oxide (NO) and cytokine levels were measured by Griess reaction and ELISA, respectively. Levels of metals in the exposure chambers were quantified by inductively coupled plasma mass spectrometry. MT expressions were quantified by immunohistochemistry in the lungs and liver of C57Bl/6 mice exposed to CS, HNBT or air (1 h, twice a day for five days: via inhalation). While both CS and HBNT exposures increased cell death, CS led to a higher number of necrotic cells, increased the production of ROS, NO, inflammatory cytokines and MTs when compared to HNBT-exposed cells, and led to a higher expression of MTs in mice. CS released higher amounts of metals. CS and HNBT exposures decreased PMA-induced interleukin-2 (IL-2) secretion and impaired Jurkat proliferation, effects also seen in cells exposed to nicotine. Although HNBT vapor does not activate T cells as CS does, exposure to both HNBT and CS suppressed proliferation and IL-2 release, a pivotal cytokine involved with T cell proliferation and tolerance, and this effect may be related to nicotine content in both products.

Flavorless vs. Flavored Electronic Cigarette-Generated Aerosol and E-Liquid on the Growth of Common Oral Commensal Streptococci

Introduction

Electronic cigarette (ECIG) use or vaping has become popular globally. While the question “Is vaping safer than smoking?” continues, it is becoming clearer that one of the most dangerous components of E-liquids are the flavorings. Since the oral cavity is the first anatomical site to be assaulted by ECIG aerosol, the aim of this study is to test the hypothesis that flavored ECIG aerosols or E-liquids pose a more detrimental effect on the growth of commensal oral streptococcal bacteria compared to flavorless aerosols or E-liquids.

Methods

Kirby Bauer assays and 24-h planktonic growth curves were used to compare the effects of flavorless vs. flavored (tobacco, menthol, cinnamon, strawberry and blueberry) ECIG-generated aerosols and E-liquids on the growth of four common strains of oral commensal bacteria (Streptococcus gordonii, Streptococcus intermedius, Streptococcus mitis and Streptococcus oralis).

Results

Kirby Bauer assays revealed inhibition of growth for all bacteria tested when exposed to 100% menthol, cinnamon or strawberry flavors. In contrast, 5% flavor in E-liquid had no effect. When exposed to 100 puffs of ECIG-generated aerosol ± flavors (≈ 0.05% flavor in brain heart infusion media) or an equivalent amount of E-liquid ± flavors, twenty-four hour planktonic growth curves indicated no effect on growth for all streptococci tested. Subsequent twenty-four hour planktonic growth curves testing the effects of E-liquid ± flavors (0.0625, 0.125, 0.25, 0.3125, 0.625, and 1.25% flavor in brain heart infusion media) revealed dose-dependent inhibition of growth, particularly for menthol, cinnamon and strawberry), for all bacteria tested.

Conclusion

These results support the hypothesis that flavored E-liquids are more detrimental to the growth of oral commensal bacteria than unflavored E-liquids. The streptococci tested in this study are early colonizers and part of the foundation of oral biofilms and dental plaque. Disturbances in the composition and growth of these primary colonizers is crucial to the development of a healthy dental plaque and host-bacteria interactions. E-liquids and their aerosols containing flavoring agents alter the growth of these bacteria. Such perturbations of pioneering oral communities pose a potential risk to the health of the oral cavity and, ultimately, health in general.

Cross-sectional study on the awareness, susceptibility and use of heated tobacco products among adolescents in Guatemala City, Guatemala

OBJECTIVES

Heated tobacco products (HTPs) are increasingly marketed worldwide, yet limited research on HTPs has been conducted in low and middle-income countries (LMICs) or among adolescents. Guatemala is one of the few LMICs where HTPs are available. This study examined prevalence and correlates of HTP awareness, susceptibility and use among adolescents in Guatemala.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional survey on HTP awareness, susceptibility and use was conducted among 2870 students between the ages of 13 and 17 in private schools in Guatemala City, Guatemala.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was susceptibility to future use of HTP among school-aged current and never smokers in Guatemala. We also explored awareness and use of HTPs. Multivariate binomial regression models were used to explore associations between these outcomes and both sociodemographic factors and established smoking correlates.

RESULTS

Of all students (n=2870), about half were aware of HTPs (52.4%) and susceptible to future or continued use (52.4%). Whereas 8.4% of students had tried HTPs in the lifetime (but not in the last month), only 2.9% used HTPs in the past month. Independent correlates of HTP susceptibility and ever-use included: use of other tobacco products (current smoking: adjusted OR (AOR)=10.53 and 6.63, respectively; current e-cigarette use: AOR=21.87 and 10.40, respectively), moderate alcohol consumption (AOR=1.49 and 1.19, respectively), marijuana use in the past 30 days (AOR=3.49 and 2.29, respectively) and having friends who use HTPs (AOR=1.83 and 7.28, respectively).

CONCLUSIONS

Among this sample of adolescents in Guatemala City, where tobacco control is weak, the prevalence of HTP use was low but susceptibility to future use was high. Tobacco prevention and intervention strategies for cigarettes and e-cigarettes should now also include HTPs, which tend to be used by similar adolescent populations (ie, those who use other substances or are exposed to tobacco through family and friends).

Heat-not-burn tobacco products: an emerging threat to cardiovascular health

Cigarette smoking is at all-time lows globally, but the use of electronic cigarettes has increased profoundly. Recent reports of electronic cigarette or vaping use-associated lung injury may lead individuals to explore novel methods of nicotine consumption, such as heat-not-burn devices. IQOS from Philip Morris, a heat-not-burn device, became available for purchase in the United States in October 2019. Philip Morris claims that 8.8 million people have abandoned traditional cigarettes in favor of IQOS; however, evidence suggests that it may act as a gateway or complement to cigarette smoking, rather than a replacement. Surveys indicate that 96% of Korean IQOS users also smoke cigarettes, and 45% of Italian users of IQOS had never smoked cigarettes. In the United States, Canada, and England, susceptibility of youth to trying IQOS was slightly lower than electronic cigarettes, but higher than cigarette smoking. Heat-not-burn products produce mainstream and second-hand emissions of harmful chemicals, including nicotine, particulate matter, benzene, acrolein, and tobacco-specific nitrosamines. The levels of these emissions, despite being less than those of traditional cigarettes, are potentially harmful to cardiovascular health. A study of current smokers showed similar acute effects of heat-not-burn tobacco products and traditional cigarettes on heart rate, blood pressure, and arterial stiffness. Rats exposed to IQOS had similar vascular endothelial function impairment to those exposed to cigarettes. Heat-not-burn aerosol exposure of cultured macrophages elicited increased oxidative stress, although less than that induced by cigarette smoke. Further studies are needed to better understand the cardiovascular effects of heat-not-burn tobacco products.

Heat-Not-Burn cigarette induces oxidative stress response in primary rat alveolar epithelial cells

There has been an increase in the usage of heat-not-burn (HNB) cigarette products. However, their effects on alveolar epithelial cells (AECs) remain unknown. AECs are the target cells of conventional cigarette smoking-related respiratory diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis and lung cancer whose pathogenesis involves oxidative stress. In this study, primary rat AECs were isolated, cultured and stimulated by HNB cigarette smoke extract (CSE). Our data indicate that rat AECs exposed to HNB CSE induced oxidative stress response genes (e.g. Hmox-1, Gsta1, Gsta3 and Nqo1). We also compared the oxidative stress response between two different types of AECs, alveolar type I-like (ATI-like) cells and type II (ATII) cells, and between two different types of cigarette, HNB cigarettes and conventional cigarettes. The expressions of Gsta1, Gsta3 and Nqo1 were higher in ATII cells than ATI-like cells in response to HNB and conventional cigarettes, but there was no significant difference in their expression levels between HNB cigarette and conventional cigarette. Taken together, our results suggest that HNB cigarettes have the similar potential as conventional cigarette products to induce oxidative stress response in AECs.

Reasons for Regularly Using Heated Tobacco Products among Adult Current and Former Smokers in Japan: Finding from 2018 ITC Japan Survey

The market growth of heated tobacco products (HTPs), such as IQOS, Ploom TECH, and glo, has increased dramatically in Japan since 2016. Little is known about the reasons why current and former smokers are using HTPs. The data for this cross-sectional study were from the 2018 (Wave 1) International Tobacco Control (ITC) Japan Survey, a national web-based survey of 4500 people, including 658 current HTP users, of whom 549 were concurrently smoking cigarettes and 109 were former smokers. The most common reasons for regularly using HTPs were: beliefs that HTP are less harmful than cigarettes to themselves (90.6%) or to others (86.7%), enjoyment (76.5%), and social acceptability (74.4%). About half of current smokers (55.1%) reported using HTPs because these products might help them quit smoking. However, a near-equal percentage (52.0%) of current smokers reported using HTPs to replace some of the cigarettes they smoked so that they did not have to give up smoking altogether. If smokers are using HTPs to complement rather than quit their smoking, then the harm reduction potential of HTPs suggested by the toxicity studies will be diminished.

Novel tobacco products including electronic cigarette and heated tobacco products increase risk of allergic rhinitis and asthma in adolescents: Analysis of Korean youth survey

BACKGROUND

The effect of novel tobacco products, such as electronic cigarettes (EC) and heated tobacco products (HTP), on allergic rhinitis (AR) and asthma is not well known.

OBJECTIVE

To evaluate the health effect of novel tobacco products on asthma and AR.

METHODS

This study was conducted using large survey data on Korean middle and high school students. The relationship between current asthma/AR and novel tobacco products user status was evaluated. In order to compare the combined effects of conventional cigarette (CC), EC, and HTP use on current allergic diseases, the participants were classified into 18 groups based on CC (current, former, and never), EC (current, former, and never), and HTP (ever and never) status.

RESULTS

A total of 60,040 participants representing 2,850,118 Korean adolescents were analyzed. Of all participants, 6.7%, 2.7%, and 2.9% were current CC, current EC, and ever HTP users, respectively. Current CC and ever HTP use was significantly associated with current asthma and AR in adjusted models. Current EC showed association with current AR but the association with asthma disappeared in the adjusted model. Among 18 groups, the groups including current CC use showed higher risk of current AR and asthma than never HTP-never EC-never CC group. The odds ratio of current asthma especially increased more in those who used EC and/or HTP with CC concurrently than those in the never HTP-never EC-current CC user group.

CONCLUSION

Using EC and/or HTP in adolescents might enhance the adverse effect of CC on AR and asthma.

Clinical Features of E-cigarette, or Vaping, Product Use-Associated Lung Injury in Teenagers

BACKGROUND

In the United States in 2019, there was an outbreak of electronic cigarette, or vaping, product use-associated lung injury (EVALI). The manifestations of EVALI in adolescents are not well characterized. We describe the diagnosis, evaluation, and management of EVALI in adolescents hospitalized at a tertiary care, university-affiliated children's hospital.

METHODS

A multidisciplinary committee developed an EVALI algorithm on the basis of guidelines from the Centers for Disease Control and Prevention. A retrospective chart review was conducted on patients diagnosed with EVALI. Descriptive analyses included sociodemographic characteristics, clinical presentation, laboratory and imaging results, pulmonary function testing, oxygen requirements, and clinic follow-up.

RESULTS

Thirteen hospitalized adolescents were diagnosed with confirmed or probable EVALI. The majority were female (54%) with a mean age of 15.9 years. Sixty-nine percent of patients presented with respiratory symptoms, whereas gastrointestinal symptoms were prominent in 85% of patients. Vaping Δ-9-tetrahydrocannabinol was reported in 92% of patients, and vaping nicotine was reported in 62% of patients. All had bilateral ground-glass opacities on the chest computed tomography (CT) scan. Treatment with glucocorticoids led to clinical improvement in 11 of 12 patients. Treatment with glucocorticoids led to improvement in both forced expiratory volume in 1 second and forced vital capacity (P < .05). Four patients required home oxygen on the basis of 6-minute walk test results.

CONCLUSIONS

Diagnosis of EVALI should be suspected on the basis of vaping history and clinical presentation. Glucocorticoid treatment led to an improvement in symptoms and lung function. The 6-minute walk test may help determine oxygen needs at discharge.

Analysis of FDA's IQOS marketing authorisation and its policy impacts

BACKGROUND

Philip Morris Products SA (PMPSA) submitted a premarket tobacco application (PMTA) to US Food and Drug Administration (FDA) seeking an order permitting it to market IQOS in the USA. US law requires FDA to deny marketing authorisation if applicants fail to demonstrate that their product is 'appropriate for the protection of the public health'. FDA issued a marketing order for IQOS in April 2019, which Philip Morris is using to promote IQOS outside the USA.

METHODS

We analysed FDA's Technical Project Lead Review and marketing order for IQOS, relevant law and guidance on PMTAs and independent research on the health impacts of IQOS.

RESULTS

FDA found that the evidence PMPSA submitted did not demonstrate reduction in long-term disease risks and that IQOS aerosol emits toxins with carcinogenic and genotoxic potential, some at higher levels than conventional cigarettes. PMPSA did not appropriately consider the health impacts of dual use, the product's attractiveness to youth or data showing that consumers do not accurately perceive the addiction risks of IQOS. Despite FDA's own scientists' recommendations and independent research showing that IQOS presents serious risks to users including cytotoxic, genotoxic, hepatotoxic, cardiovascular and pulmonary risks, FDA concluded that IQOS is 'appropriate for the protection of the public health'.

CONCLUSION

FDA's decision allowing IQOS to be marketed in the USA disregarded valid scientific evidence and misapplied the public health standard mandated by law. This decision may have important health impacts, influence marketing IQOS outside the USA and erode public confidence in FDA's future PMTA decisions.

Acute Effects of a Heat-Not-Burn Tobacco Product on Pulmonary Function

Background and objectives: During the last decade, conventional tobacco smoking is experiencing a decline and new smoking products have been introduced. IQOS ("I-Quit-Ordinary-Smoking") is a type of "heat-not-burn" (HNB) tobacco product. The impact of IQOS on respiratory health is currently not defined. The objectives of this study were to evaluate the acute effects of IQOS on pulmonary function in non-smokers and current smokers. Materials and Methods: Fifty male healthy non-smokers and current smokers with no known co-morbidity underwent an exhaled CO measurement, oximetry (SaO2%), pulmonary function tests (flows, volumes and diffusion capacity), and a measurement of respiratory resistances with an impulse oscillometry system (IOS) before and immediately after IQOS use. Results: In the whole group of 50 participants, SaO2%, forced expiratory flow at 25% and 50% of vital capacity (FEF 25%, FEF 50%, respectively), peak expiratory flow (PEF), and diffusion lung capacity for carbon monoxide/VA (KCO) decreased significantly after IQOS use, whereas exhaled CO and airway resistance (R5 Hz, R10 Hz, r15 Hz, R20 Hz, R25 Hz, R35 Hz) increased. When the groups of smokers and non-smokers were compared, in both groups (all males, 25 smokers and 25 non-smokers), exhaled CO increased and SaO2% decreased after IQOS use (p < 0.001). In the group of non-smokers, PEF (pre 8.22 ± 2.06 vs. post 7.5 ± 2.16, p = 0.001) and FEF 25% (pre 7.6 ± 1.89 vs. 7.14 ± 2.06, p = 0.009) decreased significantly; respiratory resistances R20 Hz (pre 0.34 ± 0.1 vs. post 0.36 ± 0.09, p = 0.09) and R25 Hz (pre 0.36 ± 0.1 vs. post 0.38 ± 0.09, p = 0.08) increased almost significantly. In smokers, PEF (pre 7.69 ± 2.26 vs. post 7.12 ± 2.03, p = 0.007) and expiratory reserve volume (ERV) (pre 1.57 ± 0.76 vs. post1.23 ± 0.48, p = 0.03) decreased and R35 Hz (pre 0.36 ± 0.11 vs. post 0.39 ± 0.11, p = 0.047) increased. The differences in the changes after the use of IQOS did not differ between groups. Conclusions: IQOS had an impact on exhaled CO, SaO2%, and airways function immediately after use. Even though these changes were rather small to be considered of major clinical importance, they should raise concerns regarding the long-term safety of this product. Further research is needed for the short- and long-term effects of IQOS, especially in patients with respiratory disease.

Adult Smokers' Awareness and Interest in Trying Heated Tobacco Products: Perspectives from Mexico, where HTPs and E-Cigarettes Are Banned

BACKGROUND

We evaluated smokers' perceptions of heated tobacco products (HTPs) in Mexico, where industry publically lobbied to introduce HTPs into this country that banned both HTPs and e-cigarettes.

METHODS

Online surveys (November 2018 to July 2019) were analyzed from adults who only smoked cigarettes (n = 2091) or who smoked and used e-cigarettes ("dual users"n = 1128). Logistic models regressed HTP awareness, interest to trying HTPs, and having seen HTPs for sale (only among aware participants) on sociodemographics and tobacco-related variables.

RESULTS

Of the 17.1% who were aware of HTPs, 52.7% reported having seen HTPs for sale. Of all respondents, 75% were somewhat or very interested in trying HTPs. Compared to their counterparts, more frequent smokers, dual users, those exposed to online e-cigarette ads, and those with friends who used e-cigarettes were both more aware of and interested in trying HTPs. Greater awareness was also associated with higher education, recent attempts to quit, receipt of email e-cigarette ads, and smoking among friends and family. Seeing HTPs for sale was higher for those who recently attempted to quit, were exposed to e-cigarette ads online or by email, or had friends who used e-cigarettes.

CONCLUSION

Interest in HTPs is high among smokers in Mexico, which already has a large black market for illegal e-cigarettes. HTPs use should be monitored in this context, especially given the public health impacts of HTPs are unclear.

Concurrent Daily and Non-Daily Use of Heated Tobacco Products with Combustible Cigarettes: Findings from the 2018 ITC Japan Survey

Use of heated tobacco products (HTPs) among current smokers is becoming increasingly popular in Japan. This study aims to compare characteristics and tobacco-related behaviors among concurrent users of HTPs and combustible cigarettes (n = 644) with exclusive smokers (n = 3194) or exclusive HTP users (n = 164). The secondary aim was to explore heterogeneity within concurrent use subgroups. Data were from Wave 1 of the ITC Japan Survey, a nationally representative web survey conducted from February to March 2018. Concurrent cigarette-HTP users were younger and wealthier than exclusive smokers. However, there were no difference in the frequency of smoking, number of cigarettes per day, and smoking cessation behaviors between the two groups, suggesting that HTPs reinforce nicotine dependence. Compared to exclusive HTP users, concurrent cigarette-HTP users reported higher frequency of non-daily HTP use, and lower number of tobacco-containing inserts per day. Almost all concurrent cigarette-HTP users smoked every day (93.9%); 48.4% both smoked and used HTPs daily (dual daily users, n = 396), while 45.5% were daily smokers and non-daily HTP users (predominant smokers, n = 213). Concurrent user subgroups differed from each other on age, tobacco use behaviors, and quit intention. Alongside heterogeneity between concurrent and exclusive product users, differences across concurrent use subgroups highlight the importance of considering frequency of use in characterizing poly-tobacco users.

Acute effects of JUUL and IQOS in cigarette smokers

BACKGROUND

JUUL is an electronic cigarette that aerosolises a nicotine-containing liquid, while IQOS heats tobacco to produce an aerosol. Both are marketed to smokers, but their effects have seldom been examined in this population.

METHODS

Eighteen cigarette smokers (13 men) with no JUUL or IQOS experience completed a within-subject, laboratory study assessing nicotine delivery and subjective effects after controlled (10 puffs, ~30 s interpuff interval) and ad libitum (90 min) use of JUUL, IQOS or own-brand (OB) cigarettes.

RESULTS

JUUL increased mean plasma nicotine concentration significantly from 2.2 (SD=0.7) ng/mL to 9.8 (4.9) ng/mL after 10 puffs and to 11.5 (9.3) ng/mL after ad libitum use. IQOS increased mean plasma nicotine significantly from 2.1 (0.2) ng/mL to 12.7 (6.2) ng/mL after 10 puffs and to 11.3 (8.0) ng/mL after ad libitum use. OB increased mean plasma nicotine significantly from 2.1 (0.2) ng/mL to 20.4 (11.4) ng/mL after 10 puffs and to 21.0 (10.2) ng/mL after ad libitum use. Mean OB plasma nicotine concentration was significantly higher than JUUL and IQOS. OB increased expired carbon monoxide concentration, but IQOS and JUUL did not. 'Craving a cigarette/nicotine' and 'Urges to smoke' were reduced significantly for all products following the directed bout.

CONCLUSIONS

Among smokers, JUUL and IQOS delivered less nicotine than cigarettes. Also, in this sample, IQOS and OB reduced abstinence symptoms more effectively than JUUL. Additional work with experienced JUUL and IQOS users is needed, as their nicotine delivery profiles and subjective experiences may differ.

Effects of Exposure to Tobacco Cigarette, Electronic Cigarette and Heated Tobacco Product on Adipocyte Survival and Differentiation In Vitro

Cigarette smoking (CS) causes significant morbidity worldwide, attributed to the numerous toxicants generated by tobacco combustion. Electronic cigarettes (ECIG) and heated tobacco products (HTP) are considered alternative smoking/vaping products that deliver nicotine through an inhaled aerosol and emit fewer harmful constituents than CS. However, their long-term impacts on human health are not well established. Nicotine exposure has been linked to lipolysis and body weight loss, while smoking has been associated with insulin resistance and hyperinsulinemia. Enhanced function of beige (thermogenic) adipocytes has been proposed as a means to reduce obesity and metabolic disorders. In this study, we compared the effect of extract-enriched media via exposure of culture medium to CS, HTP aerosol, and ECIG aerosol on the viability and the differentiation of 3T3-L1 pre-adipocytes to beige adipocytes. Only CS extract caused a decrease in cell viability in a dose- and time-dependent manner. Furthermore, relative lipid accumulation and expression levels of the adipocyte markers Pgc-1α, Ppar-γ and Resistin were significantly decreased in cells exposed to CS extract. Our results demonstrate that CS extract, in contrast to HTP and ECIG extracts, significantly impairs differentiation of pre-adipocytes to beige adipocytes and may therefore impact significantly adipose tissue metabolic function.

The Use of Heated Tobacco Products is Associated with Asthma, Allergic Rhinitis, and Atopic Dermatitis in Korean Adolescents

The increasing use of new and emerging tobacco products has raised public health concern worldwide. This study aimed to assess the association between tobacco product use and the risk of allergic diseases. We used cross-sectional data of 58,336 students aged 12–18 years from the 2018 Korea Youth Risk Behavior Survey. This study considered three tobacco products, namely cigarettes, electronic cigarettes (e-cigarettes), and heated tobacco products. Descriptive analyses, as well as simple and multinomial logistic regression analyses with a complex sampling design, were performed. Multiple tobacco use had an association with the risk of each allergic disease. Use of each tobacco product was significantly associated with an increased risk of multi-morbidity of asthma, allergic rhinitis, and atopic dermatitis. Furthermore, lifetime use of each tobacco product was associated with the prevalence of atopic dermatitis. This highlights the importance of paying close attention to smoking by adolescents and its association with allergy epidemics. Future research should consider intensity of smoking and/or severity of allergic symptoms.

Heated Tobacco Products: A Review of Current Knowledge and Initial Assessments

The health risks of tobacco smoking have been documented in numerous studies and smoking rates have declined in developed countries over the last 50 years. Today, we know that cigarette smoking is the major cause of preventable deaths due to tobacco smoke induced diseases. As a consequence of an increased awareness of smoking-related health risks, heated tobacco products (HTPs) are marketed as reduced toxicant alternatives to conventional tobacco products. Manufacturers claim that levels of toxicants and hazardous compounds are significantly reduced, implying that inhalation of the modified aerosol is less harmful compared to conventional cigarettes. In this manuscript, previous assessments of HTPs are briefly summarized, including a short discussion on challenges with the adaption of standard analytical methods used for tobacco smoke. The reliability of analytical data is important for risk assessment approaches that are based on reduced toxicant exposure. In order to assess a putative reduction of health risks, an integrated study design is required that should include clinical studies and epidemiology data. One manufacturer applied for a classification as a Modified Risk Tobacco Product (MRTP) in the United States, based on extensive toxicological studies that have also been published. However, data are not yet sufficient for a reliable assessment or recognition of putatively reduced health risks. Challenges regarding a classification in Europe are also discussed briefly in this review.

IQOS - a heat-not-burn (HnB) tobacco product - chemical composition and possible impact on oxidative stress and inflammatory response. A systematic review

Objectives: This work attempts to summarize current knowledge about IQOS, the heat-not-burn tobacco products, their chemical composition and possible impact on oxidative stress and inflammatory response.Materials and Methods: The literature search was performed between January and April 2019 by a combination of terms: 'IQOS smoking', 'IQOS cigarette', 'I quit original smoking cigarette', 'heat-not-burn products', 'HnB tobacco products'.Results: The aim of IQOS system is to minimalize the exposure of its smokers to dangerous substances present in cigarette smoke and to lower the probability of development of tobacco-related diseases. As current studies suggest, this new heat-not-burn tobacco product emits significantly lower concentrations of tar, carbonyls, VOCs, CO, free radicals or nitrosamines when compared to conventional cigarette, and thus it may reduce health risk for smokers. However, it does not eliminate this risk of development of tobacco-related diseases.Discussion: For conventional tobacco smokers the IQOS products may be an alternative option, which helps to reduce exposure to hazardous and potentially hazardous constituents. However, for never-smokers using the IQOS cigarettes may develop an addiction or increase exposition to some substances, which may increase probability of tobacco-related diseases. Moreover, emission of unexpected substances depends on device cleaning strategy and puff regiments.Conclusions: There is only limited data about IQOS effect on smokers' health. The future investigation, especially comparison with healthy never-smokers or study of chronic exposure to IQOS, is needed.

Toxicity assessment of electronic cigarettes

Sale of electronic cigarette (e-cigarette) products has exponentially increased in the past decade, which raise concerns about its safety. This updated review provides the available toxicology profile of e-cigarettes, summarizing evidence from in vitro and in vivo studies. Data regarding which components in e-liquids exhibit potential toxicities are inconsistent. Some studies have reported that nicotine plays a significant role in inducing adverse outcomes and that solvents alone do not induce any adverse effects. However, other studies have suggested that nicotine is not associated with any adverse outcomes, whereas solvents and flavorings are the key components to elicit considerable deleterious effects on cells or animals. In addition, most of the studies that have compared the toxicity of e-cigarettes with tobacco cigarettes have suggested that e-cigarettes are less toxic than tobacco cigarettes. Nevertheless, scientific evidence regarding the toxicity profile of e-cigarette is insufficient owing to the lack of a standardized research approach. In the future, scientific toxicology data derived from standardized testing protocols including nicotine, ingredients analysis, the various e-cigarette devices made from different materials are urgently needed for thorough toxicology assessment. This review aims to update the toxicity profiles, identify knowledge gaps, and outline future directions for e-cigarettes research, which would greatly benefit public health professionals.

Comparison of cytotoxicity of IQOS aerosols to smoke from Marlboro Red and 3R4F reference cigarettes

This study compared the cytotoxicity of IQOS aerosols to smoke from Marlboro Red (MR) and 3R4F reference cigarettes. Aerosol/smoke solutions were tested as the gas vapor phase (GVP), particulate phase (total particulate matter or TPM), or whole aerosol/smoke (WA), the latter being what smokers actually inhale. Cytotoxicities were evaluated using the LDH, MTT and neutral red uptake (NRU) assays in conjunction with eight different cell types, mainly from the respiratory system. Most test solutions did not compromise the plasma membranes of cells (LDH). However, mitochondrial activity (MTT) and dye uptake/lysosomal activity (NRU) were equally depressed by IOQS aerosols and cigarette smoke solutions at the high concentrations. Our NRU data with mouse NIH/3T3 transformed fibroblasts were similar to those previously reported by the IQOS manufacturer and showed little cytotoxicity in the NRU assay. In both studies with NIH/3T3 cells, the results were significantly different from 3RF4 cigarette smoke, suggesting reduced toxicity with IQOS. However, by expanding evaluations to a broader spectrum of cells that included respiratory system cells and by including higher concentrations of GVP, as well as WA, cytotoxicity equivalent to that of Marlboro Red and 3R4F cigarettes was frequently observed with IQOS aerosols in the MTT and NRU assays.

A Comparison of Flavorless Electronic Cigarette-Generated Aerosol and Conventional Cigarette Smoke on the Survival and Growth of Common Oral Commensal Streptococci

Background: The use of electronic cigarettes (ECIG) has become very common. Consequently, critical analysis of the biological effects of ECIG aerosol deserves attention. Flavorless ECIG aerosol is known to comprise fewer harmful constituents than cigarette smoke. Therefore, we hypothesize that aerosol has less immediate effect on the viability of oral commensal streptococci than smoke. Methods: Survival and growth of four strains of commensal streptococci were measured after exposure to flavorless ECIG aerosol ± nicotine and smoke. Peristaltic pumps were used to transport aerosol or smoke into chambers containing recently seeded colony-forming units (CFUs) of the oral commensal streptococci on agar plates. Bacterial survival and growth, based on colony counts and sizes, were determined 24 h post-exposure. Additionally, aerosol or smoke were delivered into chambers containing pre-adhered streptococci to plastic coverslips and biofilm formation was determined 24 h post-exposure via scanning electron microscopy. Results: The results suggest that flavorless aerosol ± nicotine has a modest effect on bacterial growth both as colonies on agar and as biofilms. In contrast, smoke dramatically decreased bacterial survival and growth in all parameters measured. Conclusion: Unlike cigarette smoke, flavorless ECIG aerosol has only a small effect on the survival and growth of oral commensal streptococci.

Awareness and interest in IQOS heated tobacco products among youth in Canada, England and the USA

Introduction

Heated tobacco products (HTPs), such as IQOS, have been introduced in a growing number of international markets. However, little is known about perceptions of HTP products among youth.

Methods

Data are from Wave 1 of the International Tobacco Control Youth Tobacco and E-cigarette Survey (2017), a web-based cohort survey of 16- to 19-year-olds from Canada, England, and the United States (US). Respondents (n=12,064) were shown an image of IQOS and asked about their awareness, interest in trying, and susceptibility to trying the product. Youth awareness, interest in trying, and susceptibility to trying IQOS were analyzed using descriptive statistics, and logistic regression models were used to examine correlates of these outcomes.

Results

Overall, 7.0% of youth reported awareness of IQOS (England=5.6%, Canada=6.4%, and US=9.1%) and 38.6% expressed interest in trying the product (England=41.8%, Canada=33.0%, and US=40.9%). Within each country, all key outcomes varied by smoking status: greater proportions of youth who were currently smoking or had a history of smoking reported being aware of, interested in trying, and susceptible to trying IQOS. Interest and susceptibility to trying IQOS were associated with male sex, current tobacco use, and current e-cigarette use. Across all countries, susceptibility to trying IQOS (25.1%) was higher than for tobacco cigarettes (19.3%), but lower than for e-cigarettes (29.1%).

Conclusions

Awareness of heated tobacco products, such as IQOS, is emerging among youth in Canada, England, and the US. Interest in trying these products is very high among smokers, but also present among non-smokers.

IQOSTM vs. e-Cigarette vs. Tobacco Cigarette: A Direct Comparison of Short-Term Effects after Overnight-Abstinence

Introduction: Research from Philip Morris International's science division on its Heat-not-Burn product IQOSTM focused on its chemical, toxicological, clinical, and behavioral aspects. Independent research on the experiences and behavioral aspects of using IQOSTM, and how it compares to e-cigarettes, is largely lacking. The current randomized, cross-over behavioral trial tried to bridge the latter gaps. Methods: Participants (n = 30) came to the lab on three consecutive days after being overnight smoking abstinent. During each session, participants used one of three products (cigarette, e-cigarette, or IQOSTM) for five minutes. Exhaled CO (eCO) measurements and questionnaires were repeatedly administered throughout the session. Results: Smoking a cigarette for five minutes resulted in a significant increase of eCO, whereas using an IQOSTM resulted in a small but reliable increase (0.3 ppm). Vaping did not affect eCO. Cigarette craving reduced significantly after product use, with the decline being stronger for smoking than for e-cigarettes or IQOSTM. Withdrawal symptoms declined immediately after smoking or using IQOSTM, and with some delay after vaping. IQOSTM scored higher in terms of subjective reward/satisfaction and was slightly preferred to the e-cigarette. Discussion: Short-term use of IQOSTM has a minimal impact on eCO, is equally effective in reducing cigarette craving and withdrawal symptoms as an e-cigarette, and is slightly preferred.

Light and mild redux: heated tobacco products' reduced exposure claims are likely to be misunderstood as reduced risk claims

Introduction

Heated tobacco products (HTPs) are being marketed in several countries around the world with claims that they are less harmful than combusted cigarettes, based on assertions that they expose users to lower levels of toxicants. In the USA, Philip Morris International (PMI) has submitted an application to the Food and Drug Administration (FDA) in 2016 seeking authorisation to market its HTPs, IQOS, with reduced risk and reduced exposure claims.

Methods

We examined the PMI’s Perception and Behavior Assessment Studies evaluating perceptions of reduced risk claims that were submitted to the FDA and made publicly available.

Results

Qualitative and quantitative studies conducted by PMI demonstrate that adult consumers in the USA perceive reduced exposure claims as reduced risk claims.

Conclusion

The data in the PMI modified risk tobacco product IQOS application do not support reduced risk claims and the reduced exposure claims are perceived as reduced risk claims, which is explicitly prohibited by the FDA. Allowing PMI to promote IQOS as reduced exposure would amount to a legally sanctioned repeat of the ‘light’ and ‘mild’ fraud which, for conventional cigarettes, is prohibited by the US law and the WHO Framework Convention on Tobacco Control.