Tobacco-Free Nicotine Pouches and Their Potential Contribution to Tobacco Harm Reduction: A Scoping Review.

Tobacco harm reduction (THR) refers to strategies designed to reduce the health risks associated with tobacco smoking but may involve continued use of nicotine and/or tobacco. Next-generation products (NGPs) are a THR alternative as they do not burn tobacco or produce smoke and deliver nicotine and have fewer and substantially lower levels of harmful chemicals compared to cigarettes. Tobacco­free nicotine pouches (TFNPs) are an emerging category of nicotine­containing oral products that do not combust or contain tobacco leaf. Similar to Swedish snus, TFNPs are placed between a user's lip and gum, and nicotine is absorbed through the oral mucosa rather than being inhaled. The aim of this scoping review was to systematically collate and evaluate published scientific evidence (cut­off of 31 May 2023) identified from bibliometric databases investigating the potential of TFNPs to contribute to THR. Overall, studies examining chemical constituents indicated that the use of TFNPs may result in lower exposure to toxicants than other tobacco or nicotine-containing products, both combustible and non­combustible. This reduction in toxicant exposure has been demonstrated by multiple human biomarker studies and in vitro toxicological assessments to translate to harm reduction potential in smokers switching to TFNPs. However, further study is warranted. At present, there is some evidence from human behavioral research that TFNPs can support either transitioning away from smoking or reducing cigarette consumption. Furthermore, TFNP use appears very much limited to current users of traditional tobacco products, and youth uptake has been limited. In conclusion, the findings of this review indicate that TFNPs have the potential to support THR efforts and may help inform evidence­based regulation.

An assessment of nicotine pharmacokinetics and subjective effects of the pulze heated tobacco system compared with cigarettes.

Nicotine delivery and subjective effects are determinants of the ability of potentially less harmful tobacco products such as heated tobacco products (HTPs) to support adult smokers in switching away from cigarettes, and therefore to support tobacco harm reduction. This open-label, randomised, crossover, clinical study in 24 healthy adult smokers study assessed nicotine pharmacokinetics and subjective effects of the Pulze Heated Tobacco System (HTS; Pulze HTP device and three iD stick variants-Intense American Blend, Regular American Blend and Regular Menthol) compared with subjects' usual brand cigarettes (UBC). Cmax and AUCt were highest for UBC and significantly lower for each Pulze HTS variant. Cmax and AUCt were significantly higher for Intense American Blend compared with Regular American Blend, while AUCt was significantly higher for Intense American Blend compared with Regular Menthol. Median Tmax was lowest (i.e., nicotine delivery was fastest) for subjects' usual brand cigarettes and similar across the iD stick variants, although no between-product differences were statistically significant. All study products reduced urges to smoke; this effect was greatest for cigarettes although this was not statistically significant. Product evaluation scores for each Pulze HTS variant in the domains of 'satisfaction', 'psychological reward' and 'relief' were similar, and lower than those for UBC. These data demonstrate that the Pulze HTS effectively delivers nicotine and generates positive subjective effects, including satisfaction and reduced urge to smoke. This supports the conclusion that the Pulze HTS may be an acceptable alternative to cigarettes for adult smokers while having a lower abuse liability than cigarettes.

Curiosity and intentions to use myblu e-cigarettes and an examination of the 'gateway' theory: Data from cross-sectional nationally representative surveys.

Encouraging adult smokers who are uninterested or unwilling to quit, and would otherwise continue to smoke, to transition to potentially less harmful nicotine products such as electronic nicotine delivery systems (ENDS) may positively impact population health. However, counterbalancing this benefit is the societal concern that ENDS may be used by never smokers and youth and serve as a 'gateway' into cigarette smoking. Data were analysed from two independent surveys of the prevalence and perceptions of myblu ENDS use in the United States. Total sample size was 22,232 young adults and 23,264 adults. Being curious to use myblu was 1.6-2.0 times more likely in young adult current smokers than young adult never smokers. This likelihood was 2.8 times greater for adult current smokers compared with adult never smokers in the perceptions survey, while in the prevalence survey, there was no difference between adult current and never smokers. Intentions to use myblu were significantly greater in young adult current smokers compared with young adult never smokers in both surveys and in adults in the prevalence survey. In all surveys and age cohorts, 124 of 45,496 participants (0.1% of the total survey population) reported first using myblu prior to smoking cigarettes and went on to become established smokers. Curiosity and intentions to use myblu were generally higher in current smokers compared with never smokers. There was minimal evidence to suggest the existence of a 'gateway' effect to established cigarette smoking among never-smoking myblu users.

Behavioral intentions assessment of a disposable e-cigarette among adult current, former, and non-smokers in the United States.

Modeling the public health effects of e-cigarettes requires estimates of the likelihood that different individuals and population subgroups will start using e-cigarettes and subsequently transition to and from combustible cigarette use. To begin to generate input values for modeling efforts, this study assessed adults' behavioral intentions in relation to a disposable e-cigarette, "BIDI® Stick." An online questionnaire assessed intentions to try and use a BIDI® Stick regularly in 11 flavor variants among United States (U.S.) nationally representative samples of adult (21+ years) non-smokers (n = 2284), current smokers (n = 2391), former smokers (n = 2241), and young adult (21-24 years) non-smokers (n = 1140) of combustible cigarettes following exposure to product information and images. Current smokers rated their intentions to use a BIDI® Stick to partially or completely replace cigarettes. Positive intention to try a BIDI® Stick at least once was, for each flavor variant, highest among current smokers (22.4%-28.1%), lower among former smokers (6.0%-9.7%) and non-smokers (3.4%-5.2%), and lowest among never-smokers (1.0%-2.4%). Among current smokers, former smokers, and non-smokers, trial and regular use intentions were lowest among e-cigarette non-users and e-cigarette never-users. Approximately 23.6% of current smokers reported an intention to use a BIDI® Stick in at least one flavor to completely switch from cigarettes and/or to reduce cigarette consumption. Low trial and regular use intentions suggest that U.S. adults who do not currently smoke cigarettes and/or use e-cigarettes are unlikely to initiate use of the BIDI® Stick e-cigarette. Trial and regular use intentions are highest among adults who currently smoke cigarettes and/or use e-cigarettes. A moderate proportion of current smokers may try using a BIDI® Stick e-cigarette as a partial or complete replacement for combustible cigarettes.

E-cigarette puffing topography: The importance of assessing user behaviour to inform emissions testing.

Analysis of the chemical composition of e-cigarette emissions is an important step in determining whether e-cigarettes offer both individual and population-level harm reduction potential. Commonly, e-cigarette emissions for chemical analysis are collected when using e-cigarettes according to standardised puffing regimens, such as those recommended by the International Organization for Standardization (ISO) or the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA). While the use of such standard puffing regimens affords a degree of uniformity between studies and are also recommended by regulatory authorities who require the submission of e-cigarette emissions data to make decisions regarding allowing a product to be commercially marketed, the standardised regimens do not necessarily reflect human puffing behaviour. This can lead to under- or over-estimating real-world emissions from e-cigarettes and inaccuracy in determining their harm reduction potential. In this review, we describe how human puffing behaviour (topography) information can be collected both in the clinical laboratory and in the real world using a variety of different methodologies. We further discuss how this information can be used to dictate e-cigarette puffing regimens for collecting emissions for chemical analyses and how this may lead to better predictions both of human yields of e-cigarette emissions constituents and of risk assessments to predict e-cigarette tobacco harm reduction potential.

Human abuse liability assessment of e-cigarettes: Why, what and how?

Cigarette smoking is the world's leading cause of preventable death and disease. Alternative nicotine products such as e-cigarettes have tobacco harm reduction potential, by providing smokers with an alternative form of nicotine delivery but with either the reduced presence or absence of the numerous harmful chemicals found in combustible cigarette smoke. One aspect of importance in determining the potential of e-cigarettes to provide a viable alternative to combustible cigarettes for smokers is their ability to cause dependence, also known as their abuse liability. E-cigarettes with little or no abuse liability would be unlikely to be used as a substitute for cigarettes, whereas at least some degree of abuse liability is acknowledged as supportive both to aiding cigarette substitution or complete cessation and to preventing relapse. Given this link between abuse liability and substitution efficacy, human studies assessing the abuse liability of e-cigarettes are important to determine their true harm reduction potential. In this review, the concept of tobacco product abuse liability is discussed, along with the primary elements-pharmacokinetics and pharmacodynamics (subjective effects)-that need to be assessed to determine abuse liability. The review also presents a number of human abuse liability study design considerations and discusses what existing studies in the literature tell us about the abuse liability and harm reduction potential of e-cigarettes.

Examination of the impact of myblu electronic nicotine delivery system e-liquid nicotine strength on self-reported measures of dependence.

BACKGROUND: Greater nicotine delivery is associated with higher nicotine concentrations in electronic nicotine delivery system (ENDS) liquids. However, there is a current debate as to whether this leads to increased dependence and mitigates ENDS public health potential. METHODS: Self-reported dependence among users of myblu ENDS containing different nicotine concentrations was examined with data from a multiwave cross-sectional survey of US young adults and adults. Questions examined responses related to dependence measures and participants' most often used myblu ENDS nicotine concentration (low: 0%, 1% and 1.2%; medium: 2%, 2.4% and 2.5%; or high: 3.6% and 4%). RESULTS: A global general linear model using nicotine concentration, age and days myblu that was used in the past 30 revealed a significant difference in PROMIS scores among nicotine concentration groups (F = 4.07, p = 0.02). However, pairwise comparisons to examine which specific groups differed significantly from others showed no significant differences. Logistic regression demonstrated that strong past 30-day cravings to use myblu among participants using high or medium nicotine concentrations were not significantly different from those using a low concentration (ORs 0.66 [0.42, 1.03], p = 0.07 and 0.95 [0.49, 1.82], p = 0.98, respectively). Time to daily first use for high or medium nicotine concentration users was not significantly different from those using a low concentration (ORs 0.89 [0.70, 1.14], p = 0.35 and 0.84 [0.57, 1.25], p = 0.40, respectively). CONCLUSIONS: Use of myblu ENDS with different nicotine concentrations is not associated with differing levels of dependence. Our findings contradict the notion that high ENDS e-liquid nicotine levels generate increased dependence.

A randomised, crossover, clinical study to assess nicotine pharmacokinetics and subjective effects of the BIDI® stick ENDS compared with combustible cigarettes and a comparator ENDS in adult smokers.

BACKGROUND: Nicotine pharmacokinetic assessments of electronic nicotine delivery systems (ENDS) are crucial to understand their ability to provide an alternative to cigarette smoking. Subjective effects data also strongly contribute to this understanding. The BIDI® Stick is a disposable ENDS product which contains 59 mg/ml nicotine benzoate salt and various flavours. METHODS: In this study, we assessed nicotine pharmacokinetics and subjective effects of 6 flavour variants of BIDI® Stick ENDS in adult smokers, compared to cigarettes and a comparator ENDS product. During each of eight study visits, 18 volunteer smoker subjects randomly used one of either their usual brand (UB) of cigarette, a BIDI® Stick ENDS, or a comparator ENDS (JUUL 59 mg/ml nicotine with Virginia Tobacco flavour), during both controlled (10 puffs, 30 s apart) and ad libitum (60 min) puffing sessions. Blood samples were collected at various time points and subjective effects questionnaires were administered. RESULTS: Mean [SD] plasma nicotine Cmax 0-120 was not significantly different between BIDI® Stick ENDS with any flavour (range 15.3 [9.90] ng/ml for BIDI® Stick Winter to 17.6 [9.00] ng/ml for BIDI® Stick Classic) and UB cigarettes (16.2 [9.17] ng/ml). Mean [SD] AUC0-120 (range 569.7 [327.29] to 628.6 [408.99]  min*ng/ml for BIDI® Stick ENDS and 747.1 [325.48]  min*ng/ml for UB cigarettes) and median Tmax 0-120 (range 5-7 min for all BIDI® Stick ENDS and UB cigarettes) values were also not significantly different between BIDI® Stick ENDS and UB cigarettes, while subjective effects measures were also similar between BIDI® Stick ENDS and UB cigarettes. Mean [SD] plasma nicotine Cmax 0-120, AUC0-120, and median Tmax 0-120 were 6.8 [4.13] ng/ml, 243.6 [179.04] min*ng/ml, and 5 min, respectively, for JUUL ENDS. These values were significantly different compared with those for all BIDI® Stick ENDS and UB cigarettes for both Cmax 0-120 and AUC0-120 but not for Tmax 0-120. CONCLUSIONS: BIDI® Stick ENDS delivered nicotine to users comparably to their UB combustible cigarette and higher than JUUL ENDS, and also elicited similar subjective effects such as satisfaction and relief. Thus, the BIDI® Stick ENDS may be a satisfying alternative to cigarettes among current smokers and may support their transitioning away from cigarette smoking. TRIAL REGISTRATION: ClinicalTrials.gov (identifier number NCT05072925).

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 (Cmax) and area under the plasma concentration-time curve between 0 and 6 h (AUC0-6h) were significantly greater for the Lyft 10 mg NP than for the cigarette (both p < 0.0001), while the other NPs had Cmax and AUC0-6h 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 (Tmax) 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.

An Open-Label, Randomized, Controlled, Crossover Study to Assess Nicotine Pharmacokinetics and Subjective Effects of the JUUL System with Three Nicotine Concentrations Relative to Combustible Cigarettes in Adult Smokers.

INTRODUCTION: This randomized, open-label, crossover clinical study evaluated nicotine pharmacokinetics (PK) and subjective effects of the JUUL System (JS; Juul Labs, Inc.) with three nicotine concentrations compared to the usual brand (UB) cigarettes in 24 adult smokers. METHODS: At five study visits, subjects used either the JS in 59 mg/mL, JS 18 mg/mL (two visits), and JS 9 mg/mL (all tobacco-flavored) or smoked their UB cigarette first during a controlled puffing sequence (CPS) and then ad libitum (5 min) use sessions. Blood samples were taken at specified timepoints for 60 min in each session. The modified Product Evaluation Scale assessed subjective effects 30-min post-use in the CPS session. RESULTS: Maximum plasma nicotine concentration (Cmax-BL), total nicotine exposure (AUC0-60-BL), and rate of plasma nicotine rise were significantly lower for all JS products compared to subjects' UB cigarette in CPS and ad libitum use sessions. In both use sessions these PK parameters were significantly higher for JS 59 mg/mL compared to 18 and 9 mg/mL. Subjective measures of cigarette craving relief and "Enough Nicotine" for JS 59 mg/mL did not differ significantly from UB cigarettes, but JS 18 and 9 mg/mL were rated significantly lower than JS 59 mg/mL and UB cigarettes. CONCLUSIONS: Nicotine exposure and subjective relief were directly related to JS nicotine concentration: higher nicotine concentrations gave rise to significantly greater plasma nicotine levels and relief from craving. Heavier and more dependent smokers may require the greater nicotine delivery of JS 59 mg/mL to successfully transition away from cigarettes. IMPLICATIONS: It has been suggested that electronic nicotine delivery systems (ENDS) and other alternative nicotine delivery products that more closely mimic the nicotine pharmacokinetics (PK) of cigarettes may facilitate smokers transitioning away from cigarettes. We examined nicotine PK and subjective effects of JUUL System (JS) ENDS with three nicotine concentrations (59, 18 and 9 mg/mL) compared to combustible cigarettes. Nicotine delivery from JS ENDS was nicotine concentration dependent, with higher nicotine concentrations giving rise to higher nicotine exposure. These findings suggest that heavier and more dependent smokers may require ENDS with nicotine concentrations greater than 20 mg/mL to successfully transition away from cigarettes.

Skin sensitization in silico protocol.

The assessment of skin sensitization has evolved over the past few years to include in vitro assessments of key events along the adverse outcome pathway and opportunistically capitalize on the strengths of in silico methods to support a weight of evidence assessment without conducting a test in animals. While in silico methods vary greatly in their purpose and format; there is a need to standardize the underlying principles on which such models are developed and to make transparent the implications for the uncertainty in the overall assessment. In this contribution, the relationship between skin sensitization relevant effects, mechanisms, and endpoints are built into a hazard assessment framework. Based on the relevance of the mechanisms and effects as well as the strengths and limitations of the experimental systems used to identify them, rules and principles are defined for deriving skin sensitization in silico assessments. Further, the assignments of reliability and confidence scores that reflect the overall strength of the assessment are discussed. This skin sensitization protocol supports the implementation and acceptance of in silico approaches for the prediction of skin sensitization.

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.

Nicotine pharmacokinetics of electronic cigarettes: A review of the literature.

E-cigarettes are battery-powered electronic devices from which users can inhale nicotine following its aerosolisation from a liquid solution. Some regulators and public health bodies consider e-cigarettes as potentially playing a major role in tobacco harm reduction. Their ability to provide nicotine to smokers in both amount and in a manner and form generally similar to cigarette smoking have been proposed as key components to help smokers reduce or cease the use of combustible cigarettes. Nicotine pharmacokinetic studies of e-cigarettes have been performed for a number of years and are beginning to show how nicotine delivery is evolving as the products themselves evolve. In this review, we provide a critical overview of the literature to describe what is known about nicotine delivery from e-cigarettes. We will discuss how the progression of e-cigarette design, development, and user familiarity has allowed increases in nicotine availability to the user, in the context of how much and how rapidly nicotine is delivered during acute-use periods. This review will also provide insight into current research gaps and highlight the potential utility of modelling and the standardisation of methodologies used to assess nicotine delivery to facilitate identification of products that are best suited to displace cigarette smoking among adult smokers.

Influence of cigarette filter ventilation on smokers' mouth level exposure to tar and nicotine.

Cigarette filter ventilation allows air to be drawn into the filter, diluting the cigarette smoke. Although machine smoking reveals that toxicant yields are reduced, it does not predict human yields. The objective of this study was to investigate the relationship between cigarette filter ventilation and mouth level exposure (MLE) to tar and nicotine in cigarette smokers. We collated and reviewed data from 11 studies across 9 countries, in studies performed between 2005 and 2013 which contained data on MLE from 156 products with filter ventilation between 0% and 87%. MLE among 7534 participants to tar and nicotine was estimated using the part-filter analysis method from spent filter tips. For each of the countries, MLE to tar and nicotine tended to decrease as filter ventilation increased. Across countries, per-cigarette MLE to tar and nicotine decreased as filter ventilation increased from 0% to 87%. Daily MLE to tar and nicotine also decreased across the range of increasing filter ventilation. These data suggest that on average smokers of highly ventilated cigarettes are exposed to lower amounts of nicotine and tar per cigarette and per day than smokers of cigarettes with lower levels of ventilation.

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

Cigarette smoking causes many human diseases including cardiovascular disease, lung disease and cancer. Novel tobacco products with reduced yields of toxicants compared to cigarettes, such as tobacco-heating products, snus and electronic cigarettes, hold great potential for reducing the harms associated with tobacco use. In the UK several public health agencies have advocated a potential role for novel products in tobacco harm reduction. Public Health England has stated that "The current best estimate is that e-cigarettes are around 95% less harmful than smoking" and the Royal College of Physicians has urged public health to "Promote e-cigarettes widely as substitute for smoking". Health related claims on novel products such as 'reduced exposure' and 'reduced risk' should be substantiated using a weight of evidence approach based on a comprehensive scientific assessment. The US FDA, has provided draft guidance outlining a framework to assess novel products as Modified Risk Tobacco Products (MRTP). Based on this, we now propose a framework comprising pre-clinical, clinical, and population studies to assess the risk profile of novel tobacco products. Additionally, the utility of this framework is assessed through the pre-clinical and part of the clinical comparison of a commercial e-cigarette (Vype ePen) with a scientific reference cigarette (3R4F) and the results of these studies suggest that ePen has the potential to be a reduced risk product.

A randomised, controlled, two-Centre open-label study in healthy Japanese subjects to evaluate the effect on biomarkers of exposure of switching from a conventional cigarette to a tobacco heating product.

BACKGROUND: Smoking is a leading cause of numerous human disorders including lung cancer, chronic obstructive pulmonary disease, and atherosclerotic cardiovascular disease. The development of modified risk tobacco products (MRTPs) has been suggested as a possible way to reduce the risks of tobacco smoking by reducing exposure to cigarette smoke toxicants. This study is designed to investigate whether biomarkers of such exposure are reduced when smokers switch from smoking commercial cigarettes to using either a novel or a commercially-available tobacco heating product (THP). DESIGN AND METHODS: This study will assess biomarkers of exposure in current smokers who either remain smoking, switch to THP use, or quit all tobacco use completely, for 5 days. The study is an in-clinic (confinement) two-centre, randomised controlled clinical study with a forced-switching design. Subjects of either gender will be aged 23-55 years (minimum legal smoking age plus 3 years), of Japanese origin and with a verified smoking status (assessed by exhaled breath carbon monoxide and urinary cotinine levels). Subjects will have a usual brand cigarette within the International Organisation for Standardisation (ISO) tar band of 6-8 mg and will be judged to be healthy by medical history, physical examination, vital signs, electrocardiography (ECG), clinical biochemistry and lung function tests. The primary objective of this study is to assess changes within groups in selected biomarkers of exposure (BoE) and of biological effect (BoBE) after a forced switch from a commercial control cigarette to either a menthol or a non-menthol THP. Secondary objectives are to assess between-group differences, to determine nicotine pharmacokinetics for cigarettes and THPs, to assess subject's satisfaction with the study products, and to monitor additional endpoints related to safety and product use. DISCUSSION: Data from this study will advance our scientific understanding of the changes in exposure to cigarette smoke toxicants in smokers who switch to using a THP. TRIAL REGISTRATIONS: UMIN000024988 (25th November 2016); ISRCTN14301360 (14th December 2016).

A comparative assessment of e-cigarette aerosols and cigarette smoke on in vitro endothelial cell migration.

Cigarette smoking is a risk factor for several diseases. There has been a steep increase in the use of e-cigarettes that may offer a safer alternative to cigarette smoking. In vitro models of smoking-related diseases may provide valuable insights into disease mechanisms associated with tobacco use and could be used to assess e-cigarettes. We previously reported the application of a 'scratch wound' assay, measuring endothelial cell migration rate following artificial wounding, in the presence or absence of cigarette smoke extracts. This study reports the comparative effects of two commercial e-cigarette products (Vype ePen and Vype eStick) and a scientific reference cigarette (3R4F) on endothelial migration in vitro. Puff-matched extracts were generated using the Health Canada Intense (HCI) regime for cigarettes and a modified HCI for e-cigarettes. Exposure to 3R4F extract (20h) induced concentration-dependent inhibition of endothelial cell migration, with complete inhibition at concentrations >20%. E-cigarette extracts did not inhibit migration, even at double the 3R4F extract nicotine concentration, allowing cells to migrate into the wounded area. Our data demonstrate that e-cigarettes do not induce the inhibition of endothelial cell migration in vitro when compared to 3R4F. The scratch wound assay enables the comparative assessment between tobacco and nicotine products in vitro.

E-cigarette Nicotine Delivery: Data and Learnings from Pharmacokinetic Studies.

OBJECTIVES: E-cigarettes could potentially play a major role in tobacco harm reduction by delivering nicotine in a vapor containing significantly fewer toxicants than cigarette smoke and may aid smoking behavior changes such as reduction or cessation. METHODS: We examined blood nicotine levels in smokers who were non-accustomed to e-cigarette use (Study 1) and accustomed e-cigarette users (Study 2). We compared nicotine levels when participants used a closed modular system e-cigarette to those when participants smoked a cigarette. RESULTS: In Study 1, Cmax (geometric mean (CV)) during a 5-minute puffing period (10 puffs, 30 seconds apart) was 13.4 (51.4) ng/ ml for a regular cigarette. The e-cigarette Cmax was significantly lower (p .05) at 2.5 (67.8) ng/ml. In Study 2, during a 5-minute ad libitum puffing period, cigarette Cmax was 7.2 (130.8) ng/mL, and it was 7.8 (108.2) ng/mL for the e-cigarette. CONCLUSIONS: Our data demonstrate heterogeneity of nicotine deliveries both between products and also with the same products used by different cohorts, eg, accustomed users versus smokers. Such differences must be taken into account when determining the likely behavioral impact, on smoking reduction and cessation, of nicotine delivery data and when planning e-cigarette nicotine pharmacokinetic studies.

Influence of cigarette circumference on smoke chemistry, biological activity, and smoking behaviour.

Cigarettes with reduced circumference are increasingly popular in some countries, hence it is important to understand the effects of circumference reduction on their burning behaviour, smoke chemistry and bioactivity. Reducing circumference reduces tobacco mass burn rate, puff count and static burn time, and increases draw resistance and rod length burned during puff and smoulder periods. Smoulder temperature increases with decreasing circumference, but with no discernible effect on cigarette ignition propensity during a standard test. At constant packing density, mainstream (MS) and sidestream (SS) tar and nicotine yields decrease approximately linearly with decreasing circumference, as do the majority of smoke toxicants. However, volatile aldehydes, particularly formaldehyde, show a distinctly non-linear relationship with circumference and increases in the ratios of aldehydes to tar and nicotine have been observed as the circumference decreases. Mutagenic, cytotoxic and tumorigenic specific activities of smoke condensates (i.e. per unit weight of condensate) decrease as circumference decreases. Recent studies suggest that there is no statistical difference in mouth-level exposure to tar and nicotine among smokers of cigarettes with different circumferences. Commercially available slim cigarettes usually have changes in other cigarette design features compared with cigarettes with standard circumference, so it is difficult to isolate the effect of circumference on the properties of commercial products. However, available data shows that changes in cigarette circumference offer no discernible change to the harm associated with smoking.

Examination of the use of human sera as an exposure agent for in vitro studies investigating the effects of cigarette smoking on cellular cardiovascular disease models.

In vitro models of smoking-related diseases and disease processes are valuable for mechanistic understanding and assessment of novel tobacco products. Many laboratories have used particulate phase or aqueous extracts of cigarette smoke as an exposure system for in vitro models. However, this may not be the most relevant method of exposing cells to smoke and its toxicants. Here we have examined the use of human serum as an exposure system. Cultured human umbilical vein endothelial cells were exposed in vitro to sera (50% dilution in culture media) from human volunteers (9 smokers; 10 non-smokers) for 20 h. Statistically-significant differential changes were detected in endothelial migration in an endothelial damage repair model, such that smokers' sera had an inhibitory effect on migration compared with sera from non-smokers (p<0.05). We further observed several statistically-significant differences in cardiovascular disease (CVD)-relevant gene expression between cells exposed to smokers' and non-smokers' sera, as well as differences in levels of cytokines secreted from endothelial cells. Our data demonstrate that human sera from smokers and non-smokers can differentially regulate endothelial function. We suggest that human serum provides a relevant exposure medium for in vitro studies assessing the impact of cigarette smoking on CVD risk potential.