Mainstream Cigarette Smoke Research Articles

Prenatal cigarette smoke exposure sensitizes acetaminophen-induced liver injury by modulating miR-34a-5p in male offspring mice.

Introduction: Cigarette smoke (CS) exacerbates the severity of diseases not only in lungs, but also in systemic organs having no direct contact with smoke. In addition, smoking during pregnancy can have severe health consequences for both the mother and the fetus. Therefore, our aim was to evaluate effects of prenatal exposure to CS on acetaminophen (APAP)-induced acute liver injury (ALI) in offspring. Methods: Female C57BL/6 mice on day 6 of gestation were exposed to mainstream CS (MSCS) at 0, 150, 300, or 600μg/L for 2h a day, 5days a week for 2weeks using a nose-only exposure system. At four weeks old, male offspring mice were injected intraperitoneally with a single dose of APAP at 300mg/kg body weight to induce ALI. Results: Maternal MSCS exposure significantly amplified pathological effects associated with ALI as evidenced by elevated serum alanine aminotransferase levels, increased hepatocellular apoptosis, higher oxidative stress, and increased inflammation. Interestingly, maternal MSCS exposure reduced microRNA (miR)-34a-5p expression in livers of offspring. Moreover, treatment with a miR-34a-5p mimic significantly mitigated the severity of APAP-induced hepatotoxicity. Overexpression of miR-34a-5p completely abrogated adverse effects of maternal MSCS exposure in offspring with ALI. Mechanistically, miR-34a-5p significantly decreased expression levels of hepatocyte nuclear factor 4 alpha, leading to down-regulated expression of cytochrome P450 (CYP)1A2 and CYP3A11. Discussion: Prenatal exposure to MSCS can alter the expression of miRNAs, even in the absence of additional MSCS exposure, potentially increasing susceptibility to APAP exposure in male offspring mice.

A new paradigm in cigarette smoke detection: Rapid identification technique based on ATR-FTIR spectroscopy and GhostNet-[formula omitted]

In the tobacco field, the analysis and classification of cigarette smoke are crucial for ensuring product quality, protecting consumer health, and driving industry innovation. These analyses provide a comprehensive understanding of tobacco products and serve as a scientific basis for production standards and regulatory policies. Traditional infrared spectroscopy techniques for tobacco quality analysis often suffer from limitations such as time consumption, high costs, and complexity. To achieve efficient detection of cigarette smoke and quality control of cigarettes, this study developed a cigarette mainstream smoke detection system based on Attenuated Total Reflectance Fourier transform infrared (ATR-FTIR) spectroscopy technology, aimed at rapidly acquiring the mid-infrared (MIR) spectral characteristics of cigarette smoke and combining deep learning for rapid cigarette type identification. Five different brands of cigarettes were selected for this study, and a total of 400 MIR spectra of cigarette smoke aerosols were collected. Using three spectral preprocessing methods and two-dimensional correlation spectroscopy (2DCOS), we extracted the fingerprint region (1850–650 cm-1) to generate 4800 2DCOS images. We then optimized the GhostNet network architecture and constructed a more compact and efficient deep learning model, GhostNet-α. A mixed-precision training strategy further enhanced model training speed and computational efficiency. Results show that Multiple Scatter Correction (MSC)-preprocessed synchronous 2DCOS images achieved 100 % classification accuracy. This study validates GhostNet-α’s efficiency and accuracy in cigarette smoke recognition, offering a new technical approach for quality control and rapid detection in the tobacco industry, significantly enhancing its competitiveness and consumer health protection.

Non-targeted analytical comparison of a heated tobacco product aerosol against mainstream cigarette smoke: does heating tobacco produce an inherently different set of aerosol constituents?

Smoking-related diseases remain a significant public health concern, and heated tobacco products (HTPs) have emerged as a potential alternative to cigarettes. While several studies have confirmed that HTP aerosols contain lower levels of harmful and potentially harmful constituents (HPHCs) than cigarette smoke, less is known about constituents that are intrinsically higher in HTP aerosols. This study provides a comprehensive comparative assessment of an HTP aerosol produced with Tobacco Heating System 2.2 (THS) and comparator cigarette (CC) smoke aiming at identifying all unique or increased compounds in THS aerosol by applying a broad set of LC–MS and GC × GC–MS methods. To focus on differences due to heating versus burning tobacco, confounding factors were minimized by using the same tobacco in both test items and not adding flavorants. Of all analytical features, only 3.5%—corresponding to 31 distinctive compounds—were significantly more abundant in THS aerosol than in CC smoke. A notable subset of these compounds was identified as reaction products of glycerol. The only compound unique to THS aerosol was traced back to its presence in a non-tobacco material in the test item and not a direct product of heating tobacco. Our results demonstrate that heating a glycerol-containing tobacco substrate to the temperatures applied in THS does not introduce new compounds in the resulting aerosol compared to CC smoke which are detectable with the method portfolio applied in this study. Overall, this study contributes to a better understanding of the chemical composition of HTP aerosols and their potential impact on human health.Graphical

Lactic Acid Salts of Nicotine Potentiate the Transfer of Toxic Metals into Electronic Cigarette Aerosols.

The designs and liquid formulations of Electronic Nicotine Delivery System (ENDS) devices continue to rapidly evolve. Thus, it is important to monitor and characterize ENDS aerosols for changes in toxic constituents. Many ENDS liquid formulations now include the addition of organic acids in a 1 to 1 molar ratio with nicotine. Metal concentrations in aerosols produced by ENDS devices with different nicotine salt formulations were analyzed. Aerosols from devices containing lactic acid had higher nickel, zinc, copper, and chromium concentrations than aerosols produced by devices containing benzoic acid or levulinic acid. Our scanning electron microscope with energy dispersive X-ray analytical findings showed that the metals determined in the inductively coupled plasma-mass spectrometry analytical results were consistent with the metal compositions of the ENDS device components that were exposed to the liquids and that nickel is a major constituent in many ENDS internal components. As a result of the exposure of the nickel-containing components to the ENDS liquids, resulting aerosol nickel concentrations per puff were higher from devices that contained lactic acid in comparison to devices with benzoic or levulinic acid. The aerosol nickel concentrations in 10 puffs from ENDS-containing lactic acid were, in some cases, hundreds of times higher than cigarette mainstream smoke nickel deliveries. Thus, the design of an ENDS device in terms of both physical construction components and the liquid chemical formulations could directly impact potential exposures to toxic constituents such as metals.

Supersulfide prevents cigarette smoke extract-induced mitochondria hyperfission and cardiomyocyte early senescence by inhibiting Drp1-filamin complex formation

Smoking is one of the most serious risk factors for cardiovascular diseases. Although cigarette mainstream and sidestream smoke are significant contributors to increased cardiovascular mortality and morbidity, the underlying mechanism is still unclear. Here, we report that exposure of rat neonatal cardiomyocytes to cigarette smoke extract (CSE) induces mitochondrial hyperfission-mediated myocardial senescence. CSE leads to mitochondrial fission and reactive oxygen species (ROS) production through the complex formation between mitochondrial fission factor Drp1 and actin-binding protein, filamin A. Pharmacological perturbation of interaction between Drp1 and filamin A by cilnidipine and gene knockdown of Drp1 or filamin A inhibited CSE-induced mitochondrial hyperfission and ROS production as well as myocardial senescence. We previously reported that Drp1 activity is controlled by supersulfide-induced Cys644 polysulfidation. The redox-sensitive Cys644 was critical for CSE-mediated interaction with filamin A. The administration of supersulfide donor, Na2S3 also improved mitochondrial hyperfission-mediated myocardial senescence induced by CSE. Our results suggest the important role of Drp1-filamin A complex formation on cigarette smoke-mediated cardiac risk and the contribution of supersulfide to mitochondrial fission-associated myocardial senescence.

A Comparative In Vitro Toxicological Screening of a Closed-End Heated Tobacco Product *

SUMMARY Heated tobacco products (HTPs) are a recent category of tobacco products, with their relative safety compared to cigarette smoking and potential to help smokers to quit being two reasons why regulators may consider their market approval. Designed to heat tobacco rather than to burn in order to produce aerosol, different heating techniques are applied to commercial HTPs, which may result in differing aerosol formation. Therefore, each product requires separate assessment. This work focuses on a closed-end HTP (coded as HTP-A), which is electrically heated and designed to allow puffing air flow to bypass its tobacco section, resulting in reduced oxygen concentration within the tobacco section during heating and aerosol forming. To provide a preliminary aerosol chemistry and in vitro toxicological screening, this study assessed HTP-A against a commercial electrically heated HTP (IQOSTM, coded as HTP-B) and a 3R4F reference cigarette. Under Health Canada Intense (HCI) smoking regime, the levels of 9 regulatory priority toxicants in the aerosol of HTP-A were either reduced or comparable to those in HTP-B on a per-stick basis. Additionally, both HTPs showed significant reduction (greater than 90%) in comparison to those measured in mainstream smoke of 3R4F cigarette for these toxicants. Using a set of standard in vitro toxicological assays (Ames, Micronucleus and Neutral Red Uptake), the two HTPs showed no observable responses while significant toxicity responses were recorded for 3R4F’s total particulate matter. Based on these preliminary results, the novel closed-end HTP-A design may provide similar toxicological profiles to the comparator HTP-B. Further toxicological and clinical assessments are warranted to evaluate HTP-A’s potential for exposure or disease risk reduction. [Contrib. Tob. Nicotine Res. 32 (2023) 146–156]

Monitoring and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Mainstream Cigarette Smoke

Objectives : Cigarette smoking is an important factor in human exposure to polycyclic aromatic hydrocarbons (PAHs). Machine-smoking methods have been devised to evaluate inhalation exposure to mainstream cigarette smoke. However, there have been only a few studies that have employed these methods for PAH monitoring in Korea.Methods : Total particulate matter samples were collected from the mainstream smoke of five different cigarette types using the ISO 3308 standard smoking method. The samples were analyzed for 16 PAHs using a gas chromatograph/mass spectrometer (GC/MS) following extraction and clean-up procedures.Results and Discussion : The 16 PAH levels of cigarette samples ranged from 87.1 ng/cig to 247.4 ng/cig with an average of 135.4 ng/cig. The average fractions of PAHs classified by the number of rings were as follows: 15% (2 rings), 37% (3 rings), 43% (4 rings), 4% (5 rings), and 1% (6 rings). Diagnostic ratios suggested that the characteristics of PAH pollution in mainstream cigarette smoke were similar to those of biomass burning but different from those of ambient air. The carcinogenic risks of PAHs exceeded the risk threshold of the US EPA (1.0E-06) for the 10%, 30%, and 20% exposure groups of adult males, adult females, and all adults, respectively.Conclusion : This study highlights the significance of mainstream cigarette smoke in examining human inhalation exposure to PAHs and carcinogenic risks, which are primarily influenced by cigarette smoking rather than ambient air. These findings can contribute to a comprehensive assessment of inhalation exposure to PAHs and provide guidance for the development of environmental health policies aimed at reducing such exposure.

Effect of Capsule Burst in Cigarette Filters on the Compound Composition of Mainstream Cigarette Smoke.

The number of cigarette capsule users is increasing; however, a comprehensive epidemiological investigation comparing the harmfulness of capsule and non-capsule cigarettes, particularly concerning the composition of flavor components and mainstream smoke, is lacking. The present study aimed to investigate the effect of capsule burst on the compound composition of mainstream smoke by quantifying the Hoffmann list and flavor (geraniol, eugenol, menthofuran, and pulegone) in mainstream smoke with and without crushing the capsules. The findings indicate that while tar values tended to increase when the capsules were burst, there was no significant change observed in the other Hoffmann list components, such as nicotine, benzo[α]pyrene, tobacco-specific nitrosamines, aromatic amines, and phenolics. However, when the capsules burst, menthofuran and pulegone, which were present in the capsule and could cause toxicity, were found in the mainstream smoke via the International Standard Organization (1.5-4.0 μg/cig and 5.13-6.00 μg/cig smoking regime) and Health Canada Intense (12.8-18.2 μg/cig and 22.77-24.67 μg/cig smoking regime). Therefore, understanding the capsule composition is important, as the toxic components of the capsules can be inhaled as smoke, posing a potential health risk.

Determination of tobacco-specific nitrosamines in tobacco and mainstream cigarette smoke using one-step clean-up coupled with liquid chromatography- tandem mass spectrometry

A method for determining tobacco-specific nitrosamines (TSNAs) in tobacco and cigarette smoke using liquid chromatography-tandem mass spectrometry was established. The established method amended the deficiencies that exist in current mainstream methods. In this method, TSNAs in tobacco and cigarette smoke were extracted by water. The aqueous extract was then extracted by dichloromethane, and the extract could be analyzed by liquid chromatography-tandem mass spectrometry after a solvent replacement. This method was used to analyze flue-cured tobacco samples, and the response of the target compounds was about 10 times higher than that of the ammonium acetate extraction method. When analyzing cigarette smoke samples, the response strength and chromatographic peak purity of the target compounds were also significantly improved. The proposed method exhibited good linearities for both tobacco and cigarette smoke samples (r2 > 0.99). The limits of detection (LODs) for tobacco and cigarette smoke samples were 0.2–1.0 ng/g and 0.1–0.3 ng/cigarette, respectively. Additionally, this method exhibited desirable accuracy and precision. The TSNAs recovery values from tobacco and cigarette smoke samples ranged from 95.7 % to 107.7 % with inter- and intra-day relative standard deviations (RSDs) of less than 7.4 %. This method is simple, effective, and has wide adaptability. It is a useful upgrade to the existing methods for analyzing TSNAs in tobacco and cigarette smoke.

Effect of glycerol concentration on levels of toxicants emissions from water-pipe tobacco smoking (WTS)

Glycerol, flavorings and sweeteners constitute approximately 70% of water-pipe tobacco smoking (WTS) mixtures. Tobacco mixture combustion produces smoke toxins (e.g. carbonyl compounds), of which the type and amount are highly dependable on tobacco mixture formula. While glycerol in tobacco mixture contribute to enhanced smoking experience, its’ combustion produces toxicants such as acrolein. According to WHO, there are no approved international upper limits regulations on WTS ingredients. This study aims to assess toxicant emission levels corresponding to increasing glycerol concentration in WTS mixtures, which may aid in developing tobacco regulations towards harm reduction.MethodsLaboratory experimental study. Using laboratory water-pipe smoking machine, levels of toxicant emissions in the smoke from WTS mixture samples containing varying glycerol concentrations were measured using High-performance Liquid Chromatography (HPLC). Smoke from 5 consecutive smoking cycles with 35 puffs each (ISO 22486 standard) was led through a trapping system as described in the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) recommended method No. 74 (Determination of selected carbonyls in mainstream cigarette smoke by HPLC). Trapped carbonyls were then analysed by HPLC with a DAD detector.ResultsAcrolein emission is associated with glycerol addition in WTS mixture indicated by lab-made samples throughout all glycerol concentrations (10%, 20%, 40% and 60%), and brand samples with glycerol concentrations 10% to 20%. However, brand samples showed no increase in acrolein emission corresponding to the increase in glycerol concentrations from 20% to 60%.ConclusionThe effect of glycerol addition in waterpipe tobacco on acrolein emission varies between products. Tobacco fillers, additives and contents quality and other factors may affect toxicant emission levels. Therefore, regulatory recommendations towards defining upper limits of content concentrations require further investigations regarding potential confounders in acrolein emissions and health effects of market-available glycerol concentrations in waterpipe tobacco smoking.

Insight into the effects of different oxygen heteroatoms on nicotine adsorption from cigarette mainstream smoke

Cigarette smoke contains many chemicals, including nicotine, which is harmful and can cause health problems such as carcinogenesis disease, cardiovascular, respiratory, renal, and reproductive systems. Removal of nicotine from mainstream smoke can be done through adsorption with filters or solid adsorbents. In this study, we explored the use of activated carbons for the removal of nicotine from cigarette mainstream smoke. Activated carbons were prepared from dried hemp (Cannabis sativa) stem at an activation temperature of 350–550 °C using phosphoric acid as an activating agent. The results showed that the activated carbons with variable surface functional groups and porosity exhibited high efficiency for nicotine adsorption, removing 68–88% of nicotine from cigarette mainstream smoke. Through X-ray photoelectron spectroscopy and temperature-programmed desorption analyses, we identified that oxygen-containing functional groups, particularly carboxylic groups, exhibited a superior ability to adsorb nicotine. The computational analysis with DFT simulations further supported the importance of oxygen-containing surface functional groups in facilitating nicotine adsorption, with the carboxylic group providing the lowest adsorption energy among other functional groups.

Facile preparation of sulfonated covalent triazine frameworks for effectively detection of six carcinogenic aromatic amines in cigarette smoke

FDA reported a HPHCs (Harmful and Potentially Harmful Constituents) list for tobacco products and tobacco smoke in 2012, which contained six carcinogenic aromatic amines (AAs). In this work, a sulfonated covalent triazine frameworks (CTF-SO3H) material was synthesized and used as a solid phase extraction (SPE) absorbent for highly effective enrichment and determination of six carcinogenic AAs in cigarette mainstream smoke (MSS), coupled with HPLC-MS/MS technique. The CTF-SO3H material was prepared with a rapid and facile method, which was superior to the general methods. The characterization with Nitrogen adsorption and desorption isotherm experiment, High resolution transmission electron microscopy (HTEM), etc, indicated that the CTF-SO3H material possessed sulfonic acid groups and abundant microporous structure. And the CTF-SO3H material showed good enrichment effect for AAs due to the synergistic effect of π-π stacking and electrostatic interactions. Limits of detection (LODs) of 6 AAs with the developed method were in the range of 0.01–0.11 ng cig−1. Recoveries of 6 AAs were between 80.40% and 106.00%, while the intra-day and inter-day precisions were good (i.e. RSDintra ≤ 6.40%, RSDinter ≤ 9.90%). Commercial cigarette MSS samples were analyzed with the developed method, and a commercial cation exchange SPE column was chosen for comparison. Results obtained by two methods showed a good consistency. However, the CTF-SO3H material needed less dosage, even could be reused for 4 times. Thus, the developed method not only showed high enrichment efficiency, but also was economical.

Calculated cancer risks for polycyclic aromatic hydrocarbon mixtures in mainstream smoke of cigarettes sold in China

China is the world's largest consumer of cigarettes. However, the potential cancer risk posed by polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke, especially species other than benzo[a]pyrene (BaP) remains unclear. In this study, we collected yield data on multiple PAH species from a variety of cigarettes in the China market and calculated their smoking-related incremental lifetime cancer risk (ILCR) values. The computed ILCRs of the total PAHs (ILCRΣPAHs) for ≥95% of the brands were one order of magnitude higher than the acceptable level. ILCRBaP accounted for only 5.0%–37.7% of ILCRΣPAHs among brands, indicating that using single analyte BaP to represent ΣPAHs would significantly underestimate ILCRΣPAHs. No clear trend of changes in ILCRΣPAHs was found for Chinese cigarettes over multiple years, suggesting that smoking cessation is still the best option to minimize the cancer risk of PAHs. The comparison study showed that rarely reported PAHs from Chinese cigarettes can contribute over half of ILCRΣPAHs for several American cigarettes, highlighting the imperativeness to improve the diversity of analytes for Chinese cigarettes. Adults would need to inhale the air-borne PAHs with a BaP equivalent concentration of at least 53.1 ng/m3 to reach the ILCR value comparable to that obtained from smoking.

A Comprehensive Study on the Acidic Compounds in Gas and Particle Phases of Mainstream Cigarette Smoke

Acidic compounds constitute a group of chemicals present in mainstream cigarette smoke, among which organic acids contribute to flavoring. In order to obtain a comprehensive understanding of the constituents of acidic compounds in both the particulate and gaseous phases of the mainstream smoke of commercial cigarettes, and to delineate the difference between two types of cigarettes, the yields of acidic constituents from nine cigarettes of two commercial brands (L- and M-types) were collected and analyzed in detail by gas chromatography–mass spectrometry (GC-MS). The results identified and quantitatively analyzed 46 compounds, grouped according to the substituent groups. Compositional differences between the two cigarette types were evaluated with statistical approaches. Comparison between individual, grouped, and total acid contents, between the particulate and the gaseous phases, and between the commercial L- and M-type tobaccos were conducted and characterized by the p values obtained from Student’s t-test. Multivariate analysis was performed using principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) models to identify the acids that enable a reliable differentiation of the two types. Seventeen acidic compounds whose p < 0.05 and variable importance in projection (VIP) > 1 were identified as key components that could discriminate between the two groups of commercial cigarettes. This study may be beneficial for the development of non-combusted tobacco products, which could serve as alternatives to traditional cigarettes.

Nicotine- and tar-removed cigarette smoke extract modulates the antigen presentation function of mouse bone marrow-derived dendritic cells.

Dendritic cells (DCs) take up antigens derived from pathogens such as bacteria and viruses, and from tumor cells and induce the activation of antigen-specific T cells through major histocompatibility complex (MHC)-mediated antigen presentation. Mainstream cigarette smoke extract (CSE) has various effects, and the effects of its major components, nicotine and tar, have been extensively analyzed. Recently, the physiological effects of nicotine- and tar-removed CSE (cCSE) have also been reported. However, the effects of cCSE on DC-mediated immune responses remain unknown. In this study, we found that cCSE enhanced lipopolysaccharide (LPS)-stimulated induction of the expression of MHC-I and MHC-II on the cell surface of mouse bone marrow-derived DCs (BMDCs). In contrast, cCSE suppressed the induction of CD86 induced by stimulation with curdlan and interferon-gamma (IFN-γ). In addition, cCSE suppressed the production of IL-12, IL-23, and IL-10 by LPS and curdlan stimulation. In the presence of cCSE, LPS-stimulated BMDCs showed enhanced activation of CD4 and CD8 T cells and increased IL-2 production from T cells by antigen presentation in a mixed-leukocyte reaction assay. In contrast, cCSE did not affect the activation of T cells by curdlan- or IFN-γ-stimulated BMDCs, and curdlan-stimulated BMDCs suppressed IL-17 production from T cells and enhanced IFN-γ production. These results suggest that cCSE has different effects on the activation signals induced by LPS, curdlan, and IFN-γ in BMDCs and modulates the antigen presentation function of BMDCs. This article is protected by copyright. All rights reserved.

Non-destructive discrimination of homochromatic foreign materials in cut tobacco based on VIS-NIR hyperspectral imaging.

The presence of foreign materials (FM) not only reduces the commercial value of tobacco and the quality of cigarette products, but also affects the aroma and flavor of cigarettes. Existing tobacco deblending equipment has received little study with respect to homochromatic FM. In the present study, visible-near infrared (VIS-NIR) hyperspectral imaging technique combined with chemometrics were used to identify and visualize the homochromatic FM on the surface of thining tobacco. A comparison with conventional vision method was made to analyze the feasibility of the method. The importance of detecting FM in cut tobacco was further demonstrated by first studying the volatile organic compounds produced in cigarette mixed FM smoke and their effects on human health before conducting hyperspectral experiments. The results indicated that solid-phase microextraction and gas chromatography mass spectrometry could detect volatile organic compounds in mainstream cigarette smoke that were not cigarette components and affected consumer health. Then, spectral features of the samples were extracted from hyperspectral images for building identification models to distinguish FM from cut tobacco. The visual RGB values of cut tobacco and FM were also used for the analysis of the recognition models. The results showed that the accuracy, precision and recall reached 100.00% using the back propagation artificial neural network classification model based on the principal component analysis raw wavelengths. The visualization results based on the optimal model produced clearer localization than conventional computer vision method. The present study revealed that the VIS-NIR hyperspectral imaging technology had advantage in the detection and localization of FM on the surface of thinning tobacco, which provided a foundation for improving the quality and safety of cut tobacco production. © 2023 Society of Chemical Industry.

Tobacco Nitrate and Free Radical Levels in the Mainstream Smoke of US Cigarette Brands.

Tobacco nitrate levels have been known to impact the levels of toxicants such as polyaromatic hydrocarbons and tobacco-specific nitrosamines (TSNAs) produced during smoking. Recent work in our group showed that the intrinsic nitrate levels in individual tobacco varieties also have a large influence on the formation of gas-phase (GP) free radicals in the mainstream smoke of cigarettes produced with a single tobacco variety. As tobacco nitrate content is a potential target for future regulatory policies, we investigated whether the levels of GP free radicals in the smoke from commercially available cigarettes is also dependent on the nitrate content in the corresponding tobacco blends. GP and particulate-phase (PP) free radical yields in mainstream smoke produced from 25 popular US cigarette brands were measured by electron paramagnetic resonance (EPR) spectroscopy. For each brand, we also measured levels of the TSNAs NNN (N'-nitrosonornicotine) and NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone) via HPLC-MS and the nicotine content via GC-FID. Our results show that the intrinsic nitrate levels varied >15-fold and GP radicals varied 4-fold among the 25 brands tested. The GP radicals were correlated with intrinsic nitrate levels (r = 0.87, p < 0.001). NNK and NNN levels varied >8-fold and 12-fold, respectively. We found that NNK was moderately correlated to nitrate content (r = 0.42, p = 0.03) while the NNN was strongly correlated to the nitrate content (r = 0.65, p < 0.001). Nicotine levels varied the least (<3-fold) but showed a moderate negative correlation to nitrate content (r = -0.47, p = 0.02). No statistically significant correlation was observed between nicotine and TSNA levels in mainstream smoke. Overall, this demonstrates that the nitrate content of tobacco blends used in US cigarette brands impacts toxicant output in the mainstream smoke, although other proprietary variables (total ventilation, additives, filter type, etc.) may also modulate these results.

Selected Phenolic Compounds in Mainstream Cigarette Smoke, CORESTA Collaborative Study and Recommended Method *

SUMMARY A collaborative study among 20 participating laboratories was conducted in an effort to publish a recommended method for determination of phenols in mainstream cigarette smoke. The study was conducted using 10 test samples including reference cigarettes and commercial products from various regions (ISO 3308 total particulate matter 1–16 mg/cig) smoked under two regimes (ISO 3308 and ISO 20778). Health Canada method T-114 was chosen as a basis for the analytical methodology and therefore mainstream cigarette smoke was trapped on 44-mm glass fiber filter pads which were subsequently extracted with 1% aqueous acetic acid for analysis by high performance liquid chromatography with fluorescence detection. Statistical analysis was carried out following ISO 5725 to generate repeatability (r) and reproducibility (R) data for results from linear and rotary smoking. For reproducibility (R) expressed as a percentage of mean yield across all of the studied products and both smoking regimes, values ranged from 17–150%. The lowest “tar” yielding products had the most variable data. Results trended as expected for total particulate matter, blend type, regime, and relative analyte yields. Results supporting a robust method for hydroquinone, resorcinol, catechol, phenol, o-cresol, m-cresol, and p-cresol are reported herein and support establishment of CRM 78, ISO 23904 and ISO 23905 standardized methods. [Contrib. Tob. Nicotine Res. 32 (2023) 18–25]

The impact of puff frequency on respirable particulate matter in mainstream cigarette smoke.

Inhalation of particulate matter (PM) from cigarette smoke is hazardous to smokers and non-smokers. This contribution simulates the deposition of cigarette PM on the lung surface by trapping tobacco smoke particulates on Croton megalocarpus biochar. This study investigated one commercial cigarette (MM) and one local cigarette (RR). Biochar was incorporated into the filters of MM and RR cigarettes in order to adsorb PM from mainstream cigarette smoke. A weighed 5mg of biochar with adsorbed cigarette PM was analyzed using a scanning electron microscope and a Fourier transform infrared spectrometer. The size distribution of cigarette smoke particulates was processed using ImageJ software. At 15 s puff time, the mean particulate diameters for the commercial and the local cigarettes, respectively, can be classified as coarse ≈PM10 . Conversely, the mean particulate diameter at 2s puff time for the commercial cigarette falls under the ultrafine classification of ≤PM2.5 , whereas at the same puff time, the mean particulate diameter for the local cigarette was approximately PM2.5 . Data from Fourier transform infrared spectroscopy indicate the PM in the two model cigarettes contains aromatic structures that feature the C=C bond characterized by an intense absorption band at δs (1600 cm-1 ). This study found that PM in mainstream cigarette smoke depends on puff time. Although cigarette smoking was conducted for two model cigarettes, this study can be extended to any other form of cigarette. Moreover, this study emphasizes the need for comprehensive studies on real-world cigarette smoking conditions, taking into account cigarette smokers who use larger puff volumes.

Cytotoxicity and cell injuries of flavored electronic cigarette aerosol and mainstream cigarette smoke: A comprehensive in vitro evaluation

IntroductionAlthough electronic cigarettes (e-cigarettes) have attracted much attention due to their claimed harm-reduction effects compared with conventional cigarettes, the adverse effects of e-cigarette aerosol exposure on human health are still unclear. In this work we compared the cytotoxic effects of combustion cigarettes with four commercially available flavored electronic cigarettes and their main components on ten cell lines. Cell injury mechanism of e-cigarette aerosol and combustible cigarette smoke was also explored using cellular models. MethodsEleven kinds of e-cigarettes aerosol condensates (ECSCs) and cigarette smoke constituent’s condensates (CSC) were collected by Cambridge filter pad, and the nicotine contents were determined by UPLC to provide an equivalent nicotine dosage. The CCK-8 assay was used to measure the cell viability differences between ECSC and CSC. Based on RNA-seq results, we compared the effects of ECSC and CSC on various cell injury pathways. Oxidative stress and inflammatory responses were further tested by Western Blot, immunofluorescence, and qRT-PCR assays. ResultsCSC was found to be more cytotoxic than flavored ECSC and their main components, and BEAS-2B cell line was the most sensitive cells by comparing the IC50 value. With prolonged exposure duration and higher doses, ECSC began to exhibit cytotoxicity at and above 72 µg/mL. The IC50 values of ECSC were 15-fold higher than that of CSC. Transcriptome analyses indicated that cell injury-related processes were enriched after the treatment of CSC. CSC could significantly induce more oxidative stress and inflammatory signals than ECSC. ConclusionECSCs and their components induced significantly less cytotoxicity than CSC under the laboratory exposure conditions, and CSC caused much severe cell injuries. Our study adds to the body of scientific evidence for a more comprehensive safety evaluation of e-cigarette products as compared to cigarettes.