Assessing modified risk tobacco and nicotine products: Description of the scientific framework and assessment of a closed modular electronic cigarette

The effects of electronic cigarette use patterns on health-related symptom burden and quality of life: analysis of US prospective longitudinal cohort study data

Objective

This study aimed to examine the association between e-cigarette (EC) use patterns and health-related symptoms (fatigue, pain, and emotional problems) as well as general quality of life (QoL).

Methods

Data were analyzed from 7,225 adults across Waves 1-6 of the US Population Assessment of Tobacco and Health (PATH) study. Current combustible cigarette (CC) or EC use patterns included dual CC/EC use, exclusive EC use, non-current use of CC or EC, and exclusive CC smoking. Multivariate linear mixed-effects models were used to investigate longitudinal associations between EC use patterns, and symptom burdens/QoL scores.

Results

Those who were not currently smoking or vaping reported the lowest fatigue, pain, and emotional problems, and the best QoL, among the four groups (all p < 0.001). Compared to exclusive CC smoking, exclusive EC use was associated with a significant decrease of 0.065 units in average fatigue (95% confidence interval [CI]: -0.121, -0.009), of 0.206 units in average pain (95% CI: -0.355, -0.058), and of 0.103 units in average QoL scores (95% CI: -0.155, -0.051), with emotional problems similar over time.

Conclusion

Exclusive EC users had less health-related symptoms and better QoL than those who were exclusive CC smokers. This should be taken into account when assessing the harm reduction potential of ECs.

Development of an LC-HRMS non-targeted method for comprehensive profiling of the exposome of nicotine and tobacco product users - A showcase for cigarette smokers

The global prevalence of electronic cigarettes, heated tobacco products, and other smokeless alternatives has grown significantly in the last ten years. These products have been suggested as combustion-free alternatives for conventional tobacco products like cigarettes, aiming to reduce the negative health impacts associated with smoking. However, the impact of those products on the health and safety of the general population are still unclear, as the absolute exposure from those products has not been thoroughly studied, yet. In this project, a non-targeted LC-HRMS method was developed comprising four different analytical modes for the investigation of the exposure profile in urine of the product users. The method is characterized by its high sensitivity and reproducibility, as shown during method validation. As a proof of concept, we first applied this method to detect significant differences in biomarkers of exposure (BoEs) between smokers and non-smokers. We observed a total of 171 BoEs significantly elevated in smokers, including several well-known biomarkers of smoke exposure like nicotine and its metabolites, mercapturic acid derivatives, and phenolic compounds. Some of the detected biomarkers are present at low ng/mL concentrations in urine, proving the high sensitivity needed for a holistic exploration of the exposome. Moreover, we were able to identify BoEs that have not been reported previously for smoking, such as 2,6-dimethoxyphenol and 7-methyl-1-naphthol glucuronide.

Prevalence of Electronic Cigarette Use Among Female Residents of Al-Ahsa, Kingdom of Saudi Arabia: A Cross-Sectional Study

Background Electronic cigarettes (e-cigarettes) have gained considerable popularity on a global scale, with an increasing prevalence among younger adults. The objective of this study was to investigate the prevalence, patterns, and determinants of e-cigarette use among women in Al-Ahsa, Saudi Arabia. Methodology A cross-sectional study was conducted between October 2023 and July 2024 involving 491 adult female participants. The data were collected using a structured questionnaire and subsequently analyzed using SPSS Version 26.0 (IBM Corp., Armonk, NY, USA). Descriptive and inferential statistics, including chi-square tests, were employed to assess relationships between e-cigarette use and various independent variables. Results The prevalence of e-cigarette use among participants was 17.5%. Significant factors associated with e-cigarette use included age (highest among women aged 21 to 30 years, p = 0.038), unemployment (p = 0.011), perceived poor health (p = 0.002), and having friends or family members who use e-cigarettes (p = 0.001). The primary reasons for using e-cigarettes were influence from friends (70.9%) and family members (54.7%), curiosity (33.7%), and appealing flavors (30.2%). A considerable proportion of users reported experiencing dependence and difficulty quitting. Conclusions The prevalence of e-cigarette use among female residents of Al-Ahsa is influenced by a complex interplay of social, demographic, and perceptual factors. The findings underscore the necessity for comprehensive interventions targeting social environments and educational initiatives and addressing misconceptions about the potential risks of e-cigarettes.

Challenges in current inhalable tobacco toxicity assessment models: A narrative review

Emerging tobacco products such as electronic nicotine delivery systems (ENDS) and heated tobacco products (HTPs) have a dynamic landscape and are becoming widely popular as they claim to offer a low-risk alternative to conventional smoking. Most pre-clinical laboratories currently exploit in vitro, ex vivo, and in vivo experimental models to assess toxicological outcomes as well as to develop risk-estimation models. While most laboratories have produced a wide range of cell culture and mouse model data utilizing current smoke/aerosol generators and standardized puffing profiles, much variation still exists between research studies, hindering the generation of usable data appropriate for the standardization of these tobacco products. In this review, we discuss current state-of-the-art in vitro and in vivo models and their challenges, as well as insights into risk estimation of novel products and recommendations for toxicological parameters for reporting, allowing comparability of the research studies between laboratories, resulting in usable data for regulation of these products before approval by regulatory authorities.

Comparative toxicological assessment of cigarettes and new category products via an in vitro multiplex proteomics platform

Cigarette smoking is a risk factor for several diseases such as cancer, cardiovascular disease (CVD), and chronic obstructive pulmonary diseases (COPD), however, the underlying mechanisms are not fully understood. Alternative nicotine products with reduced risk potential (RRPs) including tobacco heating products (THPs), and e-cigarettes have recently emerged as viable alternatives to cigarettes that may contribute to the overall strategy of tobacco harm reduction due to the significantly lower levels of toxicants in these products' emissions as compared to cigarette smoke. Assessing the effects of RRPs on biological responses is important to demonstrate the potential value of RRPs towards tobacco harm reduction. Here, we evaluated the inflammatory and signaling responses of human lung epithelial cells to aqueous aerosol extracts (AqE) generated from the 1R6F reference cigarette, the glo™ THP, and the Vype ePen 3.0 e-cigarette using multiplex analysis of 37 inflammatory and phosphoprotein markers. Cellular exposure to the different RRPs and 1R6F AqEs resulted in distinct response profiles with 1R6F being the most biologically active followed by glo™ and ePen 3.0. 1R6F activated stress-related and pro-survival markers c-JUN, CREB1, p38 MAPK and MEK1 and led to the release of IL-1α. glo™ activated MEK1 and decreased IL-1β levels, whilst ePen 3.0 affected IL-1β levels but had no effect on the signaling activity compared to untreated cells. Our results demonstrated the reduced biological effect of RRPs and suggest that targeted analysis of inflammatory and cell signaling mediators is a valuable tool for the routine assessment of RRPs.

An exploratory, randomised, crossover study to investigate the effect of nicotine on cognitive function in healthy adult smokers who use an electronic cigarette after a period of smoking abstinence

BACKGROUND

As well as being associated with serious negative health outcomes, smoking has been reported to have an array of physiological and psychological effects, including effects on mood and cognitive function. Post-cessation, loss of such effects (including temporary deficits in cognitive function) have been cited as reasons for resumption of smoking. The effects of e-cigarettes and nicotine delivered by e-cigarettes on these functions have not been widely researched but may play a role in the effectiveness of e-cigarettes as a satisfactory alternative to combustible cigarettes for people who smoke, and in encouraging individuals who would otherwise continue to smoke, to transition to e-cigarettes.

METHODS

The study was an exploratory, randomised, partially-blinded, single-centre, five-arm crossover trial that recruited 40 healthy male and female people who smoke. At 5 study sessions, following a 12-h period of nicotine abstinence, participants were randomly assigned to use either a combustible cigarette, an e-cigarette of three varying nicotine strengths (18 mg/mL, 12 mg/mL or 0 mg/mL respectively) or observe a no product usage session. Participants completed pre- and post-product usage assessments to examine the product usage effect on cognitive performance (using the Cambridge Neuropsychological Test Automated Battery (CANTAB)), subjective mood and smoking urges.

RESULTS

A significant improvement in sustained attention task performance was observed following use of both the nicotine containing e-cigarettes and combustible cigarette compared to no product use. Additionally, there were no significant differences between the nicotine containing products, indicating that nicotine use enhanced sustained attention regardless of delivery format. Nicotine containing e-cigarette and combustible cigarette use also significantly improved overall mood of participants compared to no product use, with no significant differences observed between the nicotine containing products. Nicotine containing e-cigarette and combustible cigarette use significantly reduced smoking urges compared to no product use, though combustible cigarette use elicited the greatest reduction in smoking urges.

CONCLUSIONS

Overall, the nicotine containing products improved sustained attention and mood while reducing smoking urges, with the studied e-cigarettes having comparable effects to combustible cigarettes across the assessed cognitive parameters and mood measures. These results demonstrate the potential role of e-cigarettes to provide an acceptable alternative for combustible cigarettes among people who would otherwise continue to smoke. Trial registration ISRCTN (identifier: ISRCTN35376793).

An in vitro toxicological assessment of two electronic cigarettes: E-liquid to aerosolisation

Interest in the toxicological assessment of iterations of e-cigarette devices, e-liquid formulations and flavour use is increasing. Here, we describe a multiple test matrix and in vitro approach to assess the biological impact of differing e-cigarette activation mechanism (button vs. puff-activated) and heating technology (cotton vs. ceramic wick). The e-liquids selected for each device contained the same nicotine concentration and flavourings. We tested both e-liquid and aqueous extract of e-liquid aerosol using a high throughput cytotoxicity and genotoxicity screen. We also conducted whole aerosol assessment both in a reconstituted human airway lung tissue (MucilAir) with associated endpoint assessment (cytotoxicity, TEER, cilia beat frequency and active area) and an Ames whole aerosol assay with up to 900 consecutive undiluted puffs. Following this testing it is shown that the biological impact of these devices is similar, taking into consideration the limitations and capturing efficiencies of the different testing matrices. We have contextualised these responses against previous published reference cigarette data to establish the comparative reduction in response consistent with reduced risk potential of the e-cigarette products tested in this study as compared to conventional cigarettes.

A Practical Framework for Novel Electronic Nicotine Delivery System Evaluation: Chemical and Toxicological Characterization of JUUL2 Aerosol and Comparison with Reference Cigarettes

Electronic nicotine delivery systems (ENDSs) are designed as a non-combustible alternative to cigarettes, aiming to deliver nicotine without the harmful byproducts of tobacco combustion. As the category evolves and new ENDS products emerge, it is important to continually assess the levels of toxicologically relevant chemicals in the aerosols and characterize any related toxicology. Herein, we present a proposed framework for characterizing novel ENDS products (i.e., devices and formulations) and determining the reduced risk potential utilizing analytical chemistry and in vitro toxicological studies with a qualitative risk assessment. To demonstrate this proposed framework, long-term stability studies (12 months) analyzing relevant toxicant emissions from six formulations of a next-generation product, JUUL2, were conducted and compared to reference combustible cigarette (CC) smoke under both non-intense and intense puffing regimes. In addition, in vitro cytotoxicity, mutagenicity, and genotoxicity assays were conducted on aerosol and smoke condensates. In all samples, relevant toxicants under both non-intense and intense puffing regimes were substantially lower than those observed in reference CC smoke. Furthermore, neither cytotoxicity, mutagenicity, nor genotoxicity was observed in aerosol condensates generated under both intense and non-intense puffing regimes, in contrast to results observed for reference cigarettes. Following the proposed framework, the results demonstrate that the ENDS products studied in this work generate significantly lower levels of toxicants relative to reference cigarettes and were not cytotoxic, mutagenic, or genotoxic under these in vitro assay conditions.

Preliminary toxicological assessment of heated tobacco products: A review of the literature and proposed strategy

Heated tobacco products (HTP) have become increasingly common in many countries worldwide. The principle of heating tobacco, without combustion, to produce a nicotine-containing aerosol with remarkably reduced levels of other known toxins, compared to combusted tobacco cigarettes, is now well established. As these products are intended as alternatives to traditional combusted products, during the early stages of their development, it is important for manufacturers to ensure that the design of the product does not lead to any unintentionally increased or new risk for the consumer, compared to the traditional products that consumers seek to replace. There is limited guidance from tobacco product regulations concerning the requirements for performing such preliminary toxicological assessments. Here, we review the published literature on studies performed on HTPs in the pursuit of such data, outline a proposed approach that is consistent with regulatory requirements, and provide a logical approach to the preliminary toxicological assessment of HTPs.

Chemical characterisation of the vapour emitted by an e-cigarette using a ceramic wick-based technology

Fourth-generation 'pod' e-cigarette devices have been driven by technological advances in electronic atomization of the e-liquid. Use of microporous ceramic as a wicking material improves heating efficiency, but how it affects the chemical emissions of these devices is unclear. We assessed the emissions of a pod e-cigarette with innovative ceramic wick-based technology and two flavoured e-liquids containing nicotine lactate and nicotine benzoate (57 and 18 mg mL-1 nicotine, respectively). Among the studied harmful and potentially harmful constituents (HPHCs) listed by the US FDA and/or WHO TobReg, only 5 (acetone, acetaldehyde, formaldehyde, naphthalene and nornicotine) were quantified at levels of 0.14 to 100 ng puff-1. In the combustible cigarette (Kentucky reference 1R6F), levels were from 0.131 to 168 µg puff-1. Nicotine levels ranged 0.10-0.32 mg puff-1 across the 3 study products. From the 19 proposed HPHCs specifically of concern in e-cigarettes, only 3 (glycerol, isoamyl acetate and propylene glycol) were quantified. The low/undetectable levels of HPHCs reflect not only the optimal operating conditions of the e-cigarette, including an efficient supply of e-liquid by the ceramic wick without overheating, but also the potential of the e-cigarettes to be used as an alternative to combustible cigarettes.

Changes in biomarkers of exposure and biomarkers of potential harm after 360 days in smokers who either continue to smoke, switch to a tobacco heating product or quit smoking

The aim of this study was to investigate whether biomarkers of exposure (BoE) and potential harm (BoPH) are modified when smokers either continue to smoke or switch from smoking cigarettes to exclusive use of a tobacco heating product (THP) in an ambulatory setting over the period of a year, and to compare any changes with smokers who quit tobacco use completely and with never smokers' biomarker levels. Participants in this year-long ambulatory study were healthy smokers with a self-reported low intent to quit assigned either to continue smoking or switch to a THP; a group of smokers with a self-reported high intent to quit who abstained from tobacco use; and a group of never smokers. Various BoE and BoPH related to oxidative stress, cardiovascular and respiratory diseases and cancer were assessed at baseline and up to 360 days. Substantial and sustained reductions in BoE levels were found at 360 days for both participants who switched from smoking to THP use and participants who quit smoking, in many cases the reductions being of a similar order for both groups. The never smoker group typically had lower levels of the measured BoEs than either of these groups, and much lower levels than participants who continued to smoke. Several BoPHs were found to change in a favourable direction (towards never smoker levels) over the year study for participants who completely switched to THP or quit, while BoPHs such as soluble intercellular adhesion molecule-1 were found to change in an unfavourable direction (away from never smoker levels) in participants who continued to smoke. Our findings, alongside chemical and toxicological studies undertaken on the THP used in this study, lead to the conclusion that smokers who would have otherwise continued to smoke and instead switch entirely to the use of this THP, will reduce their exposure to tobacco smoke toxicants and as a consequence are reasonably likely to reduce disease risks compared to those continuing to smoke.

Evaluation of behavioural, chemical, toxicological and clinical studies of a tobacco heated product glo™ and the potential for bridging from a foundational dataset to new product iterations

Background

Tobacco Heating Products (THPs) are tobacco products that heat rather than burn tobacco with temperatures less than 350 °C. Because of this operating principle, they produce substantially fewer and lower levels of tobacco smoke toxicants than combustible cigarette smoke produced when tobacco is burnt, which occurs at much higher temperatures of around 900 °C. This paper analyses data on a THP, glo™, and assesses whether its use would result in reduced health risks compared to the health risks of smoking cigarettes. It also looks at the possibility of bridging datasets across the different variants of the glo™ product.

Methods

The approach is to consider whether datasets from behavioural, chemical, toxicological and clinical studies provide consistent findings of reductions in toxicant exposure with glo™ use by subjects who switch completely from smoking cigarettes to using glo™ and whether these reductions are similar to those who stop smoking cigarettes without switching to glo™ or any other tobacco or nicotine product. We also examine the similarities and differences of different versions of the glo™ product and benchmark it against a THP from another manufacturer.

Results

The studies indicate that the use of the glo™ results in substantial and prolonged reductions in toxicant exposure for smokers who switch to glo™ completely. A long-term clinical study shows substantial reductions in toxicant exposure over a period of time, similar to reduction of some biomarkers of exposure found following smoking cessation without switching to glo™ or any other tobacco product, and biomarkers of potential harm trending in a favourable manner for both groups that switch to glo™ and that quit all tobacco and nicotine use. Data suggests that all iterations of glo™ result in substantial reductions in toxicant exposure compared to smoking cigarettes and that bridging across datasets is feasible.

Conclusions

Given the accumulated scientific data summarised in this paper, and particularly the findings from a long-term clinical study, the data demonstrate that glo™ is a reduced exposure product compared to combustible cigarettes and is reasonably deemed to reduce the risk of smoking-related diseases and supports the conclusion that smokers who would have otherwise continued to smoke and instead switch entirely to THP glo™ use, will reduce their relative risk of developing smoking-related diseases as compared to continued smoking. The extent of reduction in risk compared to continuing to smoke is likely to vary by smoking-related disease and by an individuals' smoking history, other risk factors and an individual's susceptibility to disease. Use of the THP will present some level of increased health risk as compared to cessation of tobacco and nicotine products and will cause dependence. As long as the principles of heat-not-burn are maintained, THP use will result in substantially reduced exposure to smoke toxicants as compared to continued conventional cigarette smoking. It is possible to use bridging or read across to apply these conclusions to new iterations of the glo™ product, extending the utility and validity of the evidence generated through study of prior iterations.

A randomised study to assess the nicotine pharmacokinetics of an oral nicotine pouch and two nicotine replacement therapy products

Nicotine replacement therapies (NRTs) are intended for short-term use to help cigarette smokers to quit. Some smokers find NRTs ineffective or seek a more satisfactory source of nicotine. Tobacco-free oral nicotine pouch (NP) products have emerged as a potential reduced risk product compared with cigarettes and other tobacco products. In a randomised crossover clinical study, thirty-four healthy adult smokers were enrolled and their nicotine C_max and AUC_0-T determined for three 4 mg nicotine products (NP, gum, lozenge) under fasting conditions. The NP, lozenge and gum mean C_max values were 8.5, 8.3 and 4.4 ng/mL, AUC_0-T values were 30.6, 31.5 and 14.3 ng*h/mL, respectively. The NP showed similar nicotine bioavailability to the lozenge (p = 0.6526 (C_max), p = 1.0000 (AUC_0-T)), and superior bioavailability to the gum (p  < 0.0001 for C_max and AUC_0-T). Compared with the lozenge, the NP demonstrated greater product satisfaction with a higher number of positive responses to subjective satisfaction questions. All products were judged to be well-tolerated; the incidence of minor adverse events was lower for the NP (18.2%) than the lozenge (33.3%) or gum (18.8%). In summary, NPs may provide smokers with a more satisfying alternative nicotine source as compared to the reference NRTs.

Study Registry/Registered Trial No: ISRCTN/ISRCTN65708311.

A 3D in vitro comparison of two undiluted e-cigarette aerosol generating systems

In vitro studies play an important role in supporting the toxicological assessment of e-cigarettes, with many current methods reliant on sophisticated in vitro exposure systems designed for conventional cigarette testing. In this study, we have compared two distinct systems; the modified Vitrocell VC10 and Borgwaldt LM4E designed to deliver undiluted e-cigarette aerosol. We assessed the cytotoxicity response of 3D reconstituted lung tissue (MucilAir) exposed to undiluted aerosol from ePen3 (closed modular e-cigarette) using these two exposure systems. As the induced cytotoxicity profiles were comparable, we then compared these responses against historical eBox (open modular e-cigarette) and 3R4F reference cigarette data to show evolution of product technology. This latter approach was deemed possible by monitoring intrinsic donor-to-donor control variability over a three-year period, bridging between exposure systems and observed biological responses. Despite the differences in the technology, on a puff-by-puff basis these machines gave remarkably similar cytotoxicity profiles for ePen3, as determined by MTT, and consistency of pre-cytotoxicity markers: transepithelial electrical resistance (TEER), cilia beat frequency and cilia active area. When responses are compared as a function of exposed nicotine concentration, we see differences due to the dynamics of the exposure systems. The parity of responses between the systems in generated undiluted aerosol has allowed us to compare back to previously published eBox data, irrespective of aerosol generating system and MucilAir donor, showing how evolution from open systems to podmod e-cigarette design can make a step change in the cytotoxicity profile of the product.

The role of cancer stromal fibroblasts in mediating the effects of tobacco-induced cancer cell growth

Tobacco products cause a variety of cancers, nicotine and carcinogens are two major factors to link the tobacco products and various cancers. The mechanism of tobacco inducing carcinogenesis and promoting cancer progression have been studied for a long time. However, mainstream studies just focus on the mutagenic characteristics of tobacco product and its properties to induce carcinogenesis of epithelial cells. In the past decades, people began to aware of the significant role of tumor stroma in cancer development and progression. Fibroblasts, which is associated with various cancer in all stage of disease progression, are the dominant cell type in the tumor microenvironment. While only a few studies explore the crosstalk between tobacco-induced fibroblasts and surrounding epithelial cells. Our purpose is to systematically review the effects of tobacco products on fibroblasts and further discuss how these effects affect the development of cancer cells.

A Randomised Study to Investigate the Nicotine Pharmacokinetics of Oral Nicotine Pouches and a Combustible Cigarette

Background and Objectives

Nicotine pouches (NPs) are a relatively new type of oral smokeless tobacco-free nicotine product. Currently, few data are available on the nicotine pharmacokinetics or subjective effects of NP use. The objective of this study was to determine and compare the pharmacokinetics of nicotine absorption into the blood from different NP variants and a combustible cigarette.

Methods

In a randomised, controlled, crossover clinical study, nicotine pharmacokinetics and subjective effects were compared among commercially available NPs (five different brands; 6–10 mg nicotine/pouch) and a combustible cigarette. During an 8-day confinement period, 35 healthy adult participants who were current dual users of snus and combustible cigarettes used one study product each day for a defined period following overnight nicotine abstinence.

Results

Nicotine maximum plasma concentration (C_max) and area under the plasma concentration-time curve between 0 and 6 h (AUC_0–6h) were significantly greater for the Lyft 10 mg NP than for the cigarette (both p < 0.0001), while the other NPs had C_max and AUC_0–6h values that were either greater than or similar to those of the cigarette. Plasma nicotine concentration was not associated with the nicotine contents of the NPs. Time to reach maximum plasma concentration (T_max) was higher for all NPs (60–65 min) than for the cigarette (7 min). Regarding subjective effects, liking and intent to use product again scores were higher for the cigarette than for any NP and were lowest for the NP with the lowest nicotine content.

Conclusions

This study provides important insight into nicotine pharmacokinetics and subjective effects during NP use, and demonstrates that NPs can provide nicotine in amounts sufficient to replicate cigarette smokers' nicotine uptake following a switch from conventional cigarettes to these potentially less harmful NP products. Further studies are required to ascertain how physical characteristics of NPs other than nicotine content may affect nicotine delivery, pharmacokinetics and subjective responses.

ISRCTN Clinical Trial Registry

ISRCTN17828518.

The in vitro ToxTracker and Aneugen Clastogen Evaluation extension assay as a tool in the assessment of relative genotoxic potential of e-liquids and their aerosols

In vitro (geno)toxicity assessment of electronic vapour products (EVPs), relative to conventional cigarette, currently uses assays, including the micronucleus and Ames tests. Whilst informative on induction of a finite endpoint and relative risk posed by test articles, such assays could benefit from mechanistic supplementation. The ToxTracker and Aneugen Clastogen Evaluation analysis can indicate the activation of reporters associated with (geno)toxicity, including DNA damage, oxidative stress, the p53-related stress response and protein damage. Here, we tested for the different effects of a selection of neat e-liquids, EVP aerosols and Kentucky reference 1R6F cigarette smoke samples in the ToxTracker assay. The assay was initially validated to assess whether a mixture of e-liquid base components, propylene glycol (PG) and vegetable glycerine (VG) had interfering effects within the system. This was achieved by spiking three positive controls into the system with neat PG/VG or phosphate-buffered saline bubbled (bPBS) PG/VG aerosol (nicotine and flavour free). PG/VG did not greatly affect responses induced by the compounds. Next, when compared to cigarette smoke samples, neat e-liquids and bPBS aerosols (tobacco flavour; 1.6% freebase nicotine, 1.6% nicotine salt or 0% nicotine) exhibited reduced and less complex responses. Tested up to a 10% concentration, EVP aerosol bPBS did not induce any ToxTracker reporters. Neat e-liquids, tested up to 1%, induced oxidative stress reporters, thought to be due to their effects on osmolarity in vitro. E-liquid nicotine content did not affect responses induced. Additionally, spiking nicotine alone only induced an oxidative stress response at a supraphysiological level. In conclusion, the ToxTracker assay is a quick, informative screen for genotoxic potential and mechanisms of a variety of (compositionally complex) samples, derived from cigarettes and EVPs. This assay has the potential for future application in the assessment battery for next-generation (smoking alternative) products, including EVPs.

A randomized controlled study in healthy participants to explore the exposure continuum when smokers switch to a tobacco heating product or an E-cigarette relative to cessation

Background

Cigarette smoking is associated with a number of diseases, such as cancer and cardiovascular diseases. Recently, there has been an increase in the use of electronic cigarettes (ECs) and tobacco-heating products (THPs) as an alternative to cigarettes, which may reduce the health burden associated with smoking. However, an exposure continuum when smokers switch to ECs or THPs compared to complete smoking cessation is not well established.

Methods

148 healthy smokers were randomized to either continue smoking cigarettes, switch to using the glo THP or a prototype EC, or completely quit any nicotine or tobacco product use for 5 days, after a 2-day baseline period. During this study breath and 24-h urine samples were collected for Biomarker of Exposure (BoE) analysis.

Results

After a 5-day switching period BoE levels showed a substantial significant decrease in levels from baseline in the groups using the glo THP, the prototype EC, and having quit all nicotine and tobacco use. On an exposure continuum, smokers who completely quit nicotine had the lowest levels of assessed BoEs, followed by those who switched to the EC and then those who switched to glo THP use. Participants who continued to smoke had the highest levels of BoEs.

Conclusions

THP or EC use over a 5-day period resulted in significant reductions in exposure to smoke toxicants, in some cases to levels similar to those for nicotine cessation. These results show that on an exposure continuum, nicotine cessation gives the greatest reduction in exposure to tobacco smoke toxicants, closely followed by the EC and the glo THP. These significant reductions in exposure to toxicants suggest that the glo THP and EC have the potential to be Reduced Risk Products.

Study Registration

ISRCTN80651909.

In vitro toxicological evaluation of a tobacco heating product THP COO and 3R4F research reference cigarette on human lung cancer cells

Cigarette smoking increases health risks, such as respiratory diseases and heart diseases. Despite the decline in smoking rates in some countries, millions of adults still choose to smoke cigarettes. The use of next-generation nicotine delivery devices, such as tobacco heating products (THPs), may become a potentially safer alternative to smoking. Here, we report on the development of an electrically heated THP, coded as THP COO, with three different flavored tobacco sticks. The purpose of the study was to measure the levels of a list of harmful and potentially harmful constituents (HPHCs) in the total particulate matter (TPM) generated and to conduct a set of toxicological assessments of THP COO as compared with 3R4F reference cigarette. For all 55 HPHCs identified, the levels generated by the THP tobacco sticks were significantly lower in comparison to those in 3R4F TPM. The rate of reduction of HPHCs was between 68.6% and 99.9% under Health Canada Intense (HCI) smoking regimen. Human lung cancer cells (NCI-H292) exposed to 3R4F TPM showed dose-dependent responses for most of the 15 in vitro toxicity endpoints, whereas those exposed to comparable doses of THP COO TPMs did not. Therefore, exclusive use of the THP COO products may reduce the exposure of those tested HPHCs and thus potentially reduce health risk of smoking.

Application of text mining to develop AOP-based mucus hypersecretion genesets and confirmation with in vitro and clinical samples

Mucus hypersecretion contributes to lung function impairment observed in COPD (chronic obstructive pulmonary disease), a tobacco smoking-related disease. A detailed mucus hypersecretion adverse outcome pathway (AOP) has been constructed from literature reviews, experimental and clinical data, mapping key events (KEs) across biological organisational hierarchy leading to an adverse outcome. AOPs can guide the development of biomarkers that are potentially predictive of diseases and support the assessment frameworks of nicotine products including electronic cigarettes. Here, we describe a method employing manual literature curation supported by a focused automated text mining approach to identify genes involved in 5 KEs contributing to decreased lung function observed in tobacco-related COPD. KE genesets were subsequently confirmed by unsupervised clustering against 3 different transcriptomic datasets including (1) in vitro acute cigarette smoke and e-cigarette aerosol exposure, (2) in vitro repeated incubation with IL-13, and (3) lung biopsies from COPD and healthy patients. The 5 KE genesets were demonstrated to be predictive of cigarette smoke exposure and mucus hypersecretion in vitro, and less conclusively predict the COPD status of lung biopsies. In conclusion, using a focused automated text mining and curation approach with experimental and clinical data supports the development of risk assessment strategies utilising AOPs.

A screening approach for the evaluation of tobacco-free 'modern oral' nicotine products using Real Time Cell Analysis

In many regulated industries there is an increasing pressure to provide timely and robust risk assessment data to support product launches. Real-time cell analysis (RTCA) is a tool that allows for the fast and relatively labour-free cytotoxic assessment of test compounds, compared to traditional methods. Here, we propose an application for the RTCA platform to provide a screening approach, to evaluate the cytotoxic potential of tobacco-free nicotine pouches, also termed modern oral product (MOP), to determine the contribution of differing nicotine strengths (4-11 mg) and a range of available flavour types from multiple markets, on overall product toxicity. Aqueous extracts were prepared for all products using 1 pouch in 20 mL cell culture media and applied to the cell system for 24 h. Test extract nicotine concentrations reflected the increases in product nicotine strength; however, these changes were not present in the same magnitude in the cytotoxicity data obtained from both primary human gingival fibroblasts (HGF) and an NCI-H292 human bronchial epithelial continuous cell line. Furthermore, across the range of flavours and product nicotine strengths tested, H292 cells whilst not the target organ for oral product use, accurately predicted the results seen in HGFs and could be considered a useful surrogate for fast screening studies. H292 cells are more easily cultured and for longer periods, offering a more compatible test system. In conclusion, the data demonstrate the utility of the RTCA platform for the quick assessment of a large range of product variants. Furthermore, for a cytotoxicity measure with this test product, the simple H292 cell line can predict outcomes in the more complex HGF and provide useful pre-clinical cytotoxicity screening data to inform the risk assessment of MOPs and the relative contribution of flavourings, nicotine and other components.

Multi-endpoint analysis of human 3D airway epithelium following repeated exposure to whole electronic vapor product aerosol or cigarette smoke

Smoking is a cause of serious diseases in smokers including chronic respiratory diseases. This study aimed to evaluate the tobacco harm reduction (THR) potential of an electronic vapor product (EVP, myblu™) compared to a Kentucky Reference Cigarette (3R4F), and assessed endpoints related to chronic respiratory diseases. Endpoints included: cytotoxicity, barrier integrity (TEER), cilia function, immunohistochemistry, and pro-inflammatory markers. In order to more closely represent the user exposure scenario, we have employed the in vitro 3D organotypic model of human airway epithelium (MucilAir™, Epithelix) for respiratory assessment. The model was repeatedly exposed to either whole aerosol of the EVP, or whole 3R4F smoke, at the air liquid interface (ALI), for 4 weeks to either 30, 60 or 90 puffs on 3-exposure-per-week basis. 3R4F smoke generation used the ISO 20778:2018 regime and EVP aerosol used the ISO 20768:2018 vaping regime. Exposure to undiluted whole EVP aerosol did not trigger any significant changes in the level of pro-inflammatory mediators, cilia beating function, barrier integrity and cytotoxicity when compared with air controls. In contrast, exposure to diluted (1:17) whole cigarette smoke caused significant changes to all the endpoints mentioned above. To our knowledge, this is the first study evaluating the effects of repeated whole cigarette smoke and whole EVP aerosol exposure to a 3D lung model at the ALI. Our results add to the growing body of scientific literature supporting the THR potential of EVPs relative to combustible cigarettes and the applicability of the 3D lung models in human-relevant product risk assessments.

Human Biomarker Exposure From Cigarettes Versus Novel Heat-Not-Burn Devices: A Systematic Review and Meta-Analysis

INTRODUCTION

Novel tobacco products require independent research to assess their safety. This study assessed the current literature for trials comparing levels of biomarkers of exposure (BoE) between conventional cigarettes (CC) and heat-not-burn (HNB) devices.

METHODS

Ten databases were searched using terms including: "heat not burn," "iqos," "teeps," "mrtp," "tobacco heating," and "glo" between January 1, 2010 and August 13, 2019. Randomized controlled trials (RCTs) assessing comparative BoE levels in humans using either CC or novel HNB devices were eligible. BoE were tabulated, and differences between the intervention and control groups were analyzed and combined using a random-effects meta-analysis.

RESULTS

Ten nonblinded, RCTs were eligible, involving a total of 1766 participants. Studies regularly reported on 12 BoE (including nicotine). HNB devices assessed included the "IQOS" and "glo" devices and "precursor" (being developed) HNB devices. In comparison to CC, all 12 BoEs assessed were significantly lower for participants assigned to an HNB device. In comparison to smoking abstinence, HNB devices were statistically equivalent for eight BoEs and significantly elevated for four BoEs.

CONCLUSIONS

This review found that the potential for harm to humans is reduced when using HNB devices compared to CC as indicated by significant reductions in BoE levels. Whilst these results support tobacco manufacturer claims of improved safety, the small number of studies included, limited range of BoE assessed, and involvement of the tobacco industry necessitate further independent research to confirm the HNB devices as being a safer alternative to CC.

IMPLICATIONS

This study supports claims made by tobacco manufacturers on the improved safety of HNB tobacco devices in comparison to CC. These novel devices lead to reduced exposure to key biomarkers, which are linked to the health consequences attributed to tobacco use. This has strong implications for international public health as well as further research and policy development relating to the safety aspects and legalities of novel tobacco products.

Optimization of aqueous aerosol extract (AqE) generation from e-cigarettes and tobacco heating products for in vitro cytotoxicity testing

Electronic cigarettes (e-cigarettes) and tobacco heating products (THPs) have reduced yields of toxicants and have recently emerged as a potentially safer alternative to combustible cigarettes. To understand if reduced toxicant exposure is associated with reductions in biological responses, there is a need for high-quality pre-clinical in vitro studies. Here, we investigated the cytotoxic response of human umbilical vein endothelial cells to conventional cigarette aqueous aerosol extracts (AqE) and highly concentrated AqEs from e-cigarettes (two generations of atomisers) and THPs (two variants). All AqE samples were generated by a standardized methodology and characterized for nicotine, propylene glycol and vegetable glycerol. The cigarette AqE caused a maximum 100 ± 0.00 % reduction in cell viability at 35 % dose (2.80 puffs) as opposed to 96.63 ± 2.73 % at 50 % (20 puffs) and 99.85 ± 0.23 % at 75 % (30 puffs) for the two THP variants (glo Bright Tobacco, glo Rich Tobacco), and 99.07 ± 1.61 % at the neat ePen2.0 e-cigarette (200 puffs). The AqE of the remaining e-cigarettes either resulted in an incomplete dose-response or did not elicit any response. The methods utilized were suitably sensitive to not only differentiate between cigarette, THP and e-cigarette aerosols but also to distinguish between products within each product category.

Cancer potencies and margin of exposure used for comparative risk assessment of heated tobacco products and electronic cigarettes aerosols with cigarette smoke

Health risk associated with the use of combustible cigarettes is well characterized and numerous epidemiological studies have been published for many years. Since more than a decade, innovative non-combusted tobacco products have emerged like heated tobacco products (HTP) or electronic cigarettes (EC). Long-term effects of these new products on health remain, however, unknown and there is a need to characterize associated potential health risks. The time dedicated to epidemiological data generation (at least 20 to 40 years for cancer endpoint), though, is not compatible with innovative development. Surrogates need, therefore, to be developed. In this work, non-cancer and cancer risks were estimated in a range of HTP and commercial combustible cigarettes based upon their harmful and potentially harmful constituent yields in aerosols and smoke, respectively. It appears that mean lifetime cancer risk values were decreased by more than one order of magnitude when comparing HTPs and commercial cigarettes, and significantly higher margin of exposure for non-cancer risk was observed for HTPs when compared to commercial cigarettes. The same approach was applied to two commercial ECs. Similar results were also found for this category of products. Despite uncertainties related to the factors used for the calculations and methodological limitations, this approach is valuable to estimate health risks associated to the use of innovative products. Moreover, it acts as predictive tool in absence of long-term epidemiological data. Furthermore, both cancer and non-cancer risks estimated for HTPs and ECs highlight the potential of reduced risk for non-combusted products when compared to cigarette smoking.

The in vitro assessment of a novel vaping technology

We have developed a novel vaping product (NVP) IS1.0(TT), which utilises a stainless-steel mesh to transfer and vaporise the e-liquid, mitigating some of the potential sources of toxicants that can be generated using the more traditional 'wick and coil' approach. The emissions from IS1.0(TT) have previously been found to have lower levels of toxicants overall when directly compared with a commercial wick and coil e-cig. This current study assessed the toxicological responses to aerosols from this NVP. Responses induced by IS1.0(TT)were compared to those from a 3R4F reference cigarette, using in vitro test methods which included regulatory genetic toxicological assays as well as some more contemporary screening approaches. The experimental conditions were designed to facilitate the testing of aerosol from this vaping product at doses that in most cases greatly exceeded those of the 3R4F comparator showed little to no toxicological responses and demonstrated significantly reduced effects in these in vitro assays when compared to 3R4F. Furthermore, the extreme doses tested in the present study indicate that the toxicant profile of this NVP translates to lower biological activity in vitro, and suggests that the absolute risk hazard level associated with electronic cigarettes can be reduced through continuous improvement as the technology evolves.

Vaping Cardiovascular Health Risks: an Updated Umbrella Review

Purpose of Review

Modified risk products (MRP) such as electronic vaping cigarettes (EVC) and heat-not-burn cigarettes (HNBC) are alternatives to traditional combustion cigarettes (TCC) with an expanding consumer base. Yet, their cardiovascular health risks are still unclear. We aimed to summarize the evidence base on this topic by conducting an updated umbrella review.

Recent Findings

We identified 7 systematic reviews, totaling 183 studies and reports, ranging from in vitro and in animal studies to clinical studies in apparently healthy volunteers and patients at risk of cardiovascular disease. Overall, acute EVC use was associated with several toxic effects at molecular, cellular, tissue, organ, and system level. In addition, EVC impacted adversely on blood pressure (BP) management, caused tachycardia, and worsened arterial stiffness. Finally, EVC use was associated with an increased risk of adverse clinical events, including atrial fibrillation and myocardial infarction, even if the causal link is still debated. Most reviews highlighted that the detrimental impact of EVC was of lesser magnitude of that of TCC. In addition, the differential impact of liquids and nicotine was not clearly disentangled. Finally, no review included studies on HNBC.

Summary

The present umbrella review suggests that EVC, and likely HNBC, despite clearly causing an increase in overall cardiovascular risk, may represent a temporary lesser evil than TCC in a risk-reduction or risk-modification strategy, aiming for eventual abstinence from all tobacco or nicotine products.

A randomized trial comparing the acute coronary, systemic, and environmental effects of electronic vaping cigarettes versus heat-not-burn cigarettes in smokers of combustible cigarettes undergoing invasive coronary assessment: rationale and design of the SUR-VAPES 3 trial

BACKGROUND

Traditional combustible cigarette (TCC) smoking remains a major cause of preventable cardiovascular morbidity and mortality. Modified risk products (MRP) such as electronic vaping cigarettes (EVC) and heat-not-burn cigarettes (HNBC) may be safer than TCC but may still have detrimental oxidative, platelet and vascular effects of particular importance to people with symptomatic coronary artery disease (CAD).

METHODS

We aimed to compare the acute coronary, systemic and environmental effects of two leading MRP in 20 TCC smokers admitted for invasive coronary assessment of CAD and willing to quit or after prior failed quitting attempts. After confirmation at angiography of an intermediate coronary stenosis, coronary flow reserve (CFR) will be appraised. Patients will then be randomized 1:1 to use a single EVC or a single HNBC in the catheterization laboratory, followed by repeat CFR measurement. The primary endpoint will be the change in CFR before and after product use. Quantitative coronary angiography, fractional flow reserve (FFR), and instantaneous wave-free ratio (iFR) will also be measured.

RESULTS

We expected to accrue results able to: 1) test whether MRP have in general a detrimental impact on coronary vascular function in TCC smokers; 2) test whether EVC have a different impact than HNBC on coronary function; 3) provide ancillary pathophysiologic and translational insights on the acute risk and safety profile of MRP in TCC smokers with established cardiovascular disease, including complex correlations between coronary, cardiac, systemic and environmental effects. In addition, by directly informing participants of their individual results, they will be further empowered to quit TCC.

CONCLUSIONS

The Sapienza University of Rome-Vascular Assessment of Proatherosclerotic Effects of Smoking (SUR-VAPES) 3 trial will provide important insights into the pathophysiologic cardiovascular impact of EVC and HNBC, also suitable to inform patients and individualize their smoking cessation strategy.

Novel biomarker genes which distinguish between smokers and chronic obstructive pulmonary disease patients with machine learning approach

Background

Chronic obstructive pulmonary disease (COPD) is combination of progressive lung diseases. The diagnosis of COPD is generally based on the pulmonary function testing, however, difficulties underlie in prognosis of smokers or early stage of COPD patients due to the complexity and heterogeneity of the pathogenesis. Computational analyses of omics technologies are expected as one of the solutions to resolve such complexities.

Methods

We obtained transcriptomic data by in vitro testing with exposures of human bronchial epithelial cells to the inducers for early events of COPD to identify the potential descriptive marker genes. With the identified genes, the machine learning technique was employed with the publicly available transcriptome data obtained from the lung specimens of COPD and non-COPD patients to develop the model that can reflect the risk continuum across smoking and COPD.

Results

The expression levels of 15 genes were commonly altered among in vitro tissues exposed to known inducible factors for earlier events of COPD (exposure to cigarette smoke, DNA damage, oxidative stress, and inflammation), and 10 of these genes and their corresponding proteins have not previously reported as COPD biomarkers. Although these genes were able to predict each group with 65% accuracy, the accuracy with which they were able to discriminate COPD subjects from smokers was only 29%.

Furthermore, logistic regression enabled the conversion of gene expression levels to a numerical index, which we named the “potential risk factor (PRF)” index. The highest significant index value was recorded in COPD subjects (0.56 at the median), followed by smokers (0.30) and non-smokers (0.02). In vitro tissues exposed to cigarette smoke displayed dose-dependent increases of PRF, suggesting its utility for prospective risk estimation of tobacco products.

Conclusions

Our experimental-based transcriptomic analysis identified novel genes associated with COPD, and the 15 genes could distinguish smokers and COPD subjects from non-smokers via machine-learning classification with remarkable accuracy. We also suggested a PRF index that can quantitatively reflect the risk continuum across smoking and COPD pathogenesis, and we believe it will provide an improved understanding of smoking effects and new insights into COPD.

State-of-the-art methods and devices for the generation, exposure, and collection of aerosols from heat-not-burn tobacco products

Tobacco harm reduction is increasingly recognized as a promising approach to accelerate the decline in smoking prevalence and smoking-related population harm. Potential modified risk tobacco products (MRTPs) must undergo a rigorous premarket toxicological risk assessment. The ability to reproducibly generate, collect, and use aerosols is critical for the characterization, and preclinical assessment of aerosol-based candidate MRTPs (cMRTPs), such as noncombusted cigarettes, also referred to as heated tobacco products, tobacco heating products, or heat-not-burn (HNB) tobacco products. HNB tobacco products generate a nicotine-containing aerosol by heating tobacco instead of burning it. The aerosols generated by HNB products are qualitatively and quantitatively highly different from cigarette smoke (CS). This constitutes technical and experimental challenges comparing the toxicity of HNB aerosols with CS. The methods and experimental setups that have been developed for the study of CS cannot be directly transposed to the study of HNB aerosols. Significant research efforts are dedicated to the development, characterization, and validation of experimental setups and methods suitable for HNB aerosols. They are described in this review, with a particular focus on the Tobacco Heating System version 2.2. This is intended to support further studies, the objective evaluation and verification of existing evidence, and the development of scientifically substantiated HNB MRTPs.

Structural, functional, and molecular impact on the cardiovascular system in ApoE-/- mice exposed to aerosol from candidate modified risk tobacco products, Carbon Heated Tobacco Product 1.2 and Tobacco Heating System 2.2, compared with cigarette smoke

AIM

To investigate the molecular, structural, and functional impact of aerosols from candidate modified risk tobacco products (cMRTP), the Carbon Heated Tobacco Product (CHTP) 1.2 and Tobacco Heating System (THS) 2.2, compared with that of mainstream cigarette smoke (CS) on the cardiovascular system of ApoE-/- mice.

METHODS

Female ApoE-/- mice were exposed to aerosols from THS 2.2 and CHTP 1.2 or to CS from the 3R4F reference cigarette for up to 6 months at matching nicotine concentrations. A Cessation and a Switching group (3 months exposure to 3R4F CS followed by filtered air or CHTP 1.2 for 3 months) were included. Cardiovascular effects were investigated by echocardiographic, histopathological, immunohistochemical, and transcriptomics analyses.

RESULTS

Continuous exposure to cMRTP aerosols did not affect atherosclerosis progression, heart function, left ventricular (LV) structure, or the cardiovascular transcriptome. Exposure to 3R4F CS triggered atherosclerosis progression, reduced systolic ejection fraction and fractional shortening, caused heart LV hypertrophy, and initiated significant dysregulation in the transcriptomes of the heart ventricle and thoracic aorta. Importantly, the structural, functional, and molecular changes caused by 3R4F CS were improved in the smoking cessation and switching groups.

CONCLUSION

Exposure to cMRTP aerosols lacked most of the CS exposure-related functional, structural, and molecular effects. Smoking cessation or switching to CHTP 1.2 aerosol caused similar recovery from the 3R4F CS effects in the ApoE-/- model, with no further acceleration of plaque progression beyond the aging-related rate.

Selected Harmful and Potentially Harmful Constituents Levels in Commercial e-Cigarettes

A broad range of commercially available electronic cigarette (e-cigarette) systems were tested for levels of emissions of harmful and potentially harmful constituents (HPHC), with a particular focus on the carbonyls: acetaldehyde, acrolein, and formaldehyde. The tobacco-specific nitrosamines N'-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-bipyridyl)-1-butanone; the elements arsenic, cadmium, chromium, lead, and nickel; benzene; 1,3-butadiene; and benzo(a)pyrene were also quantified. The results show that except for the levels of carbonyls, all types of e-cigarettes performed in a similar manner, and emission levels for HPHCs were generally not quantifiable. However, levels of carbonyls, especially formaldehyde, were highly variable. Overall, the lowest levels of formaldehyde were observed in cartridge systems, which generally achieved substantial reductions in yields in comparison with cigarette smoke. Formaldehyde levels in open tank systems were variable; however, the median formaldehyde levels across different brands were substantially lower than the formaldehyde levels in cigarette smoke. The results for variable-power devices operated at the highest voltage confirmed existing literature data regardless of orientation and differences in puffing regimes. Furthermore, our results show that many products deliver consistent HPHC yields over a broad range of testing conditions (with minimal variability from one device to another, under a range of puffing conditions). However, some products exhibit high variability in emissions of HPHCs. The use of air blanks is further highlighted to assess nonproduct-related contributions to HPHC levels to avoid misrepresentation of the data. Overall, our results highlight that some but not all electronic cigarettes deliver low levels of carbonyls consistently across the full e-liquid depletion cycle under different test conditions. The need for further research and standardization work on assessment of variable-voltage electronic cigarettes is emphasized.

Evaluating the effects of switching from cigarette smoking to using a heated tobacco product on health effect indicators in healthy subjects: study protocol for a randomized controlled trial

Tobacco heating products (THPs) are a potentially safer alternative to combustible cigarette smoking. Through continued use, THPs may reduce smoking-related disease risk, whilst maintaining the sensorial experience and nicotine delivery sought by smokers. While literature evidence of the biological effects of THP aerosol exposure is increasing, there remains a knowledge gap with respect to substantiation of THP reduced risk potential in longer term real-life use. This randomized, multi-centre, controlled clinical study will test the hypotheses that following a switch from combustible cigarettes to a THP for 1 year, participants will experience a sustained reduction in exposure to tobacco-related toxicants that will lead to favourable changes in health effect indicators associated with smoking-related disease development. Changes in such indicators will be contextualized against smoking cessation and never-smoker cohorts. Up to 280 participants who do not intend to quit smoking will be randomized to continued combustible smoking (arm A, up to n = 80) or a commercially available THP (arm B n = 200). Furthermore, up to 190 participants with a high intent to quit smoking will undergo smoking cessation (arm D), and 40 never smokers will serve as a control group (arm E). Recruitment numbers were determined to be sufficient to achieve n = 50 in arms A, B and D, at study end. Enrolment started in March 2018 and the trial is scheduled to be completed in March 2020. Data from this study will be a valuable addition to the growing body of evidence in the field of understanding the individual and public health impact of THPs.Clinical Trial Registration: https://www.isrctn.com/ISRCTN81075760.

Changes in Biomarkers of Exposure on Switching From a Conventional Cigarette to Tobacco Heating Products: A Randomized, Controlled Study in Healthy Japanese Subjects

BACKGROUND

Smoking is a leading cause of numerous human disorders including pulmonary disease, cardiovascular disease, and cancer. Disease development is primarily caused by exposure to cigarette smoke constituents, many of which are known toxicants. Switching smokers to modified risk tobacco products (MRTPs) has been suggested as a potential means to reduce the risks of tobacco use, by reducing such exposure.

METHODS

This randomized, controlled study investigated whether biomarkers of toxicant exposure (BoE) were reduced when smokers switched from smoking combustible cigarettes to using a novel (glo™/THP1.0) or in-market comparator (iQOS/THS) tobacco heating product (THP). One hundred eighty Japanese smokers smoked combustible cigarettes during a 2-day baseline period, followed by randomization to either continue smoking cigarettes, switch to using mentholated or non-mentholated variants of glo™, switch to using a non-mentholated variant of iQOS, or quit nicotine and tobacco product use completely for 5 days. Baseline and post-randomization 24-h urine samples were collected for BoE analysis. Carbon monoxide was measured daily in exhaled breath (eCO).

RESULTS

On day 5 after switching, urinary BoE (excluding for nicotine) and eCO levels were significantly (p < .05) reduced by medians between 20.9% and 92.1% compared with baseline in all groups either using glo™ or iQOS or quitting tobacco use. Between-group comparisons revealed that the reductions in the glo™ groups were similar (p > .05) to quitting in many cases.

CONCLUSIONS

glo™ or iQOS use for 5 days reduced exposure to smoke toxicants in a manner comparable to quitting tobacco use. THPs are reduced exposure tobacco products with the potential to be MRTPs.

IMPLICATIONS

This clinical study demonstrates that when smokers switched from smoking combustible cigarettes to using tobacco heating products their exposure to smoke toxicants was significantly decreased. In many cases, this was to the same extent as that seen when they quit smoking completely. This may indicate that these products have the potential to be reduced exposure and/or reduced risk tobacco products when used by smokers whose cigarette consumption is displaced completely.

CLINICAL TRIAL REGISTRATIONS

ISRCTN14301360 and UMIN000024988.

An inter-laboratory in vitro assessment of cigarettes and next generation nicotine delivery products

In vitro testing can facilitate the rapid assessment of next generation nicotine delivery products (NGPs) with comparisons to combustible tobacco products. In vitro assays for cytotoxicity and oxidative stress were employed at BAT (UK) and JT (Japan) to test total particulate matter (TPM) of a scientific reference cigarette and aerosol collected mass (ACM) of a commercially available E-cigarette and two tobacco heating products (THP). 3R4F TPMs were generated using the Health Canada intense (HCI) regimen, a modified regime (mHCI) for the THP ACMs and the CORESTA recommended method no. 81 for the E-cigarette ACM. Human lung cells were exposed to the test product TPM/ACMs at concentrations between 0-200 μg/ml followed by the employment of commercially available assays for endpoint analysis that included reactive oxygen species (ROS) generation, the glutathione ratio (GSH:GSSG), activation of the antioxidant response elements (ARE) and cellular viability. TPM/ACM nicotine concentrations were quantified using a UPLC-PDA technique. At both laboratories the 3R4F TPM induced significant and dose-dependent responses in all in vitro assays, whereas no significant responses could be measured for the NGP ACMs. In conclusion, both laboratories obtained comparable results across all endpoints therefore demonstrating the utility of the in vitro techniques combined with standardised test products to support the assessment of NGPs.

A six-month systems toxicology inhalation/cessation study in ApoE-/- mice to investigate cardiovascular and respiratory exposure effects of modified risk tobacco products, CHTP 1.2 and THS 2.2, compared with conventional cigarettes

Smoking is one of the major modifiable risk factors in the development and progression of chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD). Modified-risk tobacco products (MRTP) are being developed to provide substitute products for smokers who are unable or unwilling to quit, to lessen the smoking-related health risks. In this study, the ApoE-/- mouse model was used to investigate the impact of cigarette smoke (CS) from the reference cigarette 3R4F, or aerosol from two potential MRTPs based on the heat-not-burn principle, carbon heated tobacco product 1.2 (CHTP1.2) and tobacco heating system 2.2 (THS 2.2), on the cardiorespiratory system over a 6-month period. In addition, cessation or switching to CHTP1.2 after 3 months of CS exposure was assessed. A systems toxicology approach combining physiology, histology and molecular measurements was used to evaluate the impact of MRTP aerosols in comparison to CS. CHTP1.2 and THS2.2 aerosols, compared with CS, demonstrated lower impact on the cardiorespiratory system, including low to absent lung inflammation and emphysematous changes, and reduced atherosclerotic plaque formation. Molecular analyses confirmed the lower engagement of pathological mechanisms by MRTP aerosols than CS. Both cessation and switching to CHTP1.2 reduced the observed CS effects to almost sham exposure levels.

[Systematic analysis of the scientific literature on heated tobacco]

INTRODUCTION

The tobacco industry (TI) reports that heated tobacco reduces risk of tobacco use and will replace cigarettes. An analysis of the scientific literature was conducted in order to enlighten professionals and decision-makers.

METHOD

After a Medline query in February 2018, a systematic analysis was conducted.

RESULTS

Of the 100 papers published in 2008-2018, 75 have authors affiliated or linked to TI. Emissions contain gases, droplets and solid particles, so are smokes. The main products are: THS2.2 (Iqos®) which heats mini-cigarettes at 340°C, the THP1.0 (Glo®) which heats at 240°C sticks delivering about half as much nicotine, Ploom® which uses reconstituted tobacco microcapsules heated at 180°C. Under the experimental conditions, there is a reduction of toxic emissions and biological effects, but the expected risk reduction is not demonstrated. Symptoms related to passive smoking are described. The 4 epidemiological articles report that heated tobacco is used in 10 to 45% of cases by non-smokers and demonstrate the effectiveness of TI promotion campaigns. Thus, the THS2.2 is more a gateway to smoking (20%) than an exit door (11%); moreover, it is not expected risk reduction among the 69% who are mixed users.

CONCLUSIONS

While reducing emissions is documented, reducing the risk to the smoker who switches to heated-tobacco remains to be demonstrated. On the other hand, the worsening of the global tobacco risk related to the promotion of the products by the TI is anticipated, justifying that the authorities take the appropriate measures to control the promotion of heated tobacco.

Risk Assessment for Tobacco Regulation

Risk assessment is a process that uses a transparent, reproducible and pre-established methodology to evaluate alternatives for managing health-related risks. Although an array of federal agencies regularly use risk assessment to inform regulatory decisions, its application to tobacco regulation is new. By comparing examples of FDA risk assessments for food and tobacco, this paper highlights some of the challenges inherent in applying risk assessment methodologies to tobacco regulation. In doing so, it calls upon researchers to work with the FDA to develop a tobacco-specific approach to risk assessment that reflects the Tobacco Control Act's regulatory framework and the distinctive features of tobacco products and tobacco use.

In vitro systems toxicology-based assessment of the potential modified risk tobacco product CHTP 1.2 for vascular inflammation- and cytotoxicity-associated mechanisms promoting adhesion of monocytic cells to human coronary arterial endothelial cells

Cigarette smoking causes cardiovascular diseases. Heating tobacco instead of burning it reduces the amount of toxic compounds in the aerosol and may exert a reduced impact on health compared with cigarette smoke. Aqueous extract from the aerosol of a potential modified risk tobacco product, the Carbon Heated Tobacco Product (CHTP) 1.2, was compared in vitro with aqueous extract from the smoke of a 3R4F reference cigarette for its impact on the adhesion of monocytic cells to artery endothelial cells. Human coronary artery endothelial cells (HCAEC) were treated for 4 h with conditioned media from human monocytic Mono Mac 6 (MM6) cells exposed to CHTP1.2 or 3R4F extracts for 2 h or directly with those extracts freshly generated. In vitro monocyte-endothelial cell adhesion was measured concomitantly with inflammatory, oxidative stress, cytotoxicity, and death markers. Furthermore, transcriptomics analyses enabled to quantify the level of perturbation in HCAECs, and provide biological interpretation for the underlying molecular changes following exposure to 3R4F or CHTP1.2 extract. Our systems toxicology study demonstrated that approximately 10-15-fold higher concentrations of the CHTP 1.2 aerosol extract were needed to elicit similar effects as the 3R4F smoke extract on cardiovascular disease-relevant inflammation and cytotoxicity-related mechanisms and markers investigated in vitro.

Application of a direct aerosol exposure system for the assessment of biological effects of cigarette smoke and novel tobacco product vapor on human bronchial epithelial cultures

Recent advancements in in vitro exposure systems and cell culture technology enable direct exposure to cigarette smoke (CS) of human organotypic bronchial epithelial cultures. MucilAir organotypic bronchial epithelial cultures were exposed, using a Vitrocell exposure system, to mainstream aerosols from the 3R4F cigarette or from a recently developed novel tobacco vapor product (NTV). The exposure aerosol dose was controlled by dilution flow and the number of products smoked; there were five exposure conditions for 3R4F smoke and three for NTV vapor. The amount of nicotine delivered to the tissues under each condition was analyzed and that of the total particulate matter (TPM) was estimated using nicotine data. The nicotine dose was similar for the two products at the highest dose, but the estimated TPM levels from the NTV were 3.7 times the levels from the 3R4F. Following 3R4F smoke exposure, a dose dependent increase was observed in cytotoxicity, cytokine secretion, and differential gene expression. However, no changes were detected in these endpoints following NTV vapor exposure, suggesting the biological effects of NTV vapor are lower than those of conventional combustible CS. Our study design, which includes collection of biological data and dosimetry data, is applicable to assessing novel tobacco products.

Comparative biological impacts of an aerosol from carbon-heated tobacco and smoke from cigarettes on human respiratory epithelial cultures: A systems toxicology assessment

The biological impact of an aerosol of a potential modified-risk tobacco product, carbon heated tobacco product 1.2 (CHTP1.2), was comprehensively assessed for the first time in vitro using human small airway and nasal epithelial models following a systems toxicology approach. The potentially reduced effects of CHTP1.2 aerosol exposure were benchmarked against those of 3R4F cigarette smoke at similar nicotine concentrations. Experimental repetitions were conducted for which new batches of small airway and nasal cultures were exposed to CHTP1.2 aerosol or 3R4F smoke for 28 minutes. The biological impacts were determined based on a collection of endpoints including morphology, cytotoxicity, proinflammatory mediator profiles, cytochrome P450 1A1/1B1 activity, global mRNA and microRNA changes and proteome profiles. Alterations in mRNA expression were detected in cultures exposed to CHTP1.2 aerosol, without noticeable morphological changes and cytotoxicity, and minimal impact on proinflammatory mediator and proteome profiles. The changes linked to CHTP1.2 aerosol exposure, when observed, were transient. However, the impact of 3R4F smoke exposure persisted long post-exposure and greater than CHTP1.2 aerosol. Morphological changes were observed only in cultures exposed to 3R4F smoke. The lower biological effects of CHTP1.2 aerosol than 3R4F smoke exposure were observed similarly in both small airway and nasal epithelial cultures.

Assessment of tobacco heating product THP1.0. Part 1: Series introduction

We have recently developed a Tobacco Heating Product (THP) comprising an electrical heating device, commercially known as Glo™, and consumable tobacco rods, commercially known as Kent Neostiks™. We refer to this system as THP1.0; Bright tobacco-flavoured variant THP1.0(T), or THP1.0(M) Menthol-flavoured variant. In this issue, we present a series of seven pre-clinical studies conducted on THP1.0,covering the following aspects of its design, development, safety and toxicological assessment, and a paper on placing THPs on an emissions continuum.

Next-generation tobacco and nicotine products

A framework for the assessment of novel next-generation tobacco and nicotine products with the potential to reduce health risks compared with cigarettes should integrate scientific studies incorporating nonclinical, clinical, and population studies approaches. These products should have lower emissions and exhibit reduced biological effects compared with those of cigarettes, ideally approaching those of smoking cessation. The products should also be acceptable cigarette alternatives for current smokers, while not appealing to nonsmokers or former smokers. Validating harm reduction and promoting regulatory acceptance of the assessment methods require a collaborative approach by industry, independent reviewers, the public health community, and regulatory agencies. This article summarizes the science and approaches applied and considered to substantiate tobacco harm reduction in the light of regulatory requirements, presented at the 53rd Congress of the European Societies of Toxicology, 2017.

Assessment of tobacco heating product THP1.0. Part 5: In vitro dosimetric and cytotoxic assessment

Tobacco heating products (THPs) represent a subset of the next-generation nicotine and tobacco product category, in which tobacco is typically heated at temperatures of 250-350 °C, thereby avoiding many of the harmful combustion-related toxicant emissions of conventional cigarettes. In this study, we have assessed aerosol generation and cytotoxicity from two commercially available THPs, THP1.0 and THS, relative to tobacco smoke from 3R4F reference cigarettes, using an adapted Borgwaldt RM20S Smoking Machine. Quantification of nicotine in the exposed cell-culture media showed greater delivery of nicotine from both THPs than from the cigarette. Using Neutral Red Uptake assay, THPs demonstrated reduced in vitro cytotoxicity in H292 human bronchial epithelial cells as compared with 3R4F cigarette exposure at the air-liquid interface (p < 0.0001). Both THPs demonstrated a statistically similar reduction in biological response, with >87% viability relative to 3R4F at a common aerosol dilution (1:40, aerosol:air). A similar response was observed when plotted against nicotine; a statistical difference between 3R4F and THPs (p < 0.0001) and no difference between the THPs (p = 0.0186). This pre-clinical in vitro biological testing forms part of a larger package of data to help assess the safety and risk reduction potential of next-generation tobacco products relative to cigarettes, using a weight of evidence approach.