Cigarette smoke chemistry market maps under Massachusetts Department of Public Health smoking conditions

Signaling pathway perturbation analysis for assessment of biological impact of cigarette smoke on lung cells

Exposure to cigarette smoke (CS) results in injury to the epithelial cells of the human respiratory tract and has been implicated as a causative factor in the development of chronic obstructive pulmonary disease and lung cancers. The application of omics-scale methodologies has improved the capacity to understand cellular signaling processes underlying response to CS exposure. We report here the development of an algorithm based on quantitative assessment of transcriptomic profiles and signaling pathway perturbation analysis (SPPA) of human bronchial epithelial cells (HBEC) exposed to the toxic components present in CS. HBEC were exposed to CS of different compositions and for different durations using an ISO3308 smoking regime and the impact of exposure was monitored in 2263 signaling pathways in the cell to generate a total effect score that reflects the quantitative degree of impact of external stimuli on the cells. These findings support the conclusion that the SPPA algorithm provides an objective, systematic, sensitive means to evaluate the biological impact of exposures to CS of different compositions making a powerful comparative tool for commercial product evaluation and potentially for other known or potentially toxic environmental smoke substances.

Cigarette Filter Ventilation and its Relationship to Increasing Rates of Lung Adenocarcinoma

The 2014 Surgeon General's Report on smoking and health concluded that changing cigarette designs have caused an increase in lung adenocarcinomas, implicating cigarette filter ventilation that lowers smoking machine tar yields. The Food and Drug Administration (FDA) now has the authority to regulate cigarette design if doing so would improve public health. To support a potential regulatory action, two weight-of-evidence reviews were applied for causally relating filter ventilation to lung adenocarcinoma. Published scientific literature (3284 citations) and internal tobacco company documents contributed to causation analysis evidence blocks and the identification of research gaps. Filter ventilation was adopted in the mid-1960s and was initially equated with making a cigarette safer. Since then, lung adenocarcinoma rates paradoxically increased relative to other lung cancer subtypes. Filter ventilation 1) alters tobacco combustion, increasing smoke toxicants; 2) allows for elasticity of use so that smokers inhale more smoke to maintain their nicotine intake; and 3) causes a false perception of lower health risk from "lighter" smoke. Seemingly not supportive of a causal relationship is that human exposure biomarker studies indicate no reduction in exposure, but these do not measure exposure in the lung or utilize known biomarkers of harm. Altered puffing and inhalation may make smoke available to lung cells prone to adenocarcinomas. The analysis strongly suggests that filter ventilation has contributed to the rise in lung adenocarcinomas among smokers. Thus, the FDA should consider regulating its use, up to and including a ban. Herein, we propose a research agenda to support such an effort.

Impact assessment of WHO TobReg proposals for mandated lowering of selected mainstream cigarette smoke toxicants

The WHO Tobacco Product Regulation Study Group (TobReg) has proposed three regulatory models for cigarettes, each creating mandatory limits for emissions of nine smoke toxicants. One approach proposes country-specific limits, using median or 1.25× median toxicant/nicotine emission ratios. A second model provides fixed toxicant-ratio limits. The third model limits were three times the lowest toxicant emission on a market. Currently, the practical implications of these models are largely unknown. An impact assessment was conducted using cigarette data from 79 countries to identify four diverse test markets. We sampled all products from each market but limited product availability led to incomplete (80-97%) sourcing. Analysis showed that the country-specific model led to diverse (up to threefold) toxicant limits across the four markets. 70%-80% of products were non-compliant, rising to 100% in some countries with the second and the third models. With each regulatory model the main drivers of non-compliance were the tobacco-specific nitrosamines, the simultaneous application of limits for nine poorly correlated smoke toxicants, and analytical variability. Use of nicotine ratios led to compliance of some high toxicant emission products due to high nicotine emissions. Our findings suggest that these proposals would have greater impact on global markets than TobReg's stated aims.

Variation in tobacco and mainstream smoke toxicant yields from selected commercial cigarette products

There is a drive toward the mandated lowering and reporting of selected toxicants in tobacco smoke. Several studies have quantified the mainstream cigarette emissions of toxicants, providing benchmark levels. Few, however, have examined how measured toxicant levels within a single product vary over time due to natural variation in the tobacco, manufacturing and measurement. In a single centre analysis, key toxicants were measured in the tobacco blend and smoke of 3R4F reference cigarette and three commercial products, each sampled monthly for 10 months. For most analytes, monthly variation was low (coefficient of variation <15%); but higher (⩾ 20%) for some compounds present at low (ppb) levels. Reporting toxicant emissions as a ratio to nicotine increased the monthly variation of the 9 analytes proposed for mandated lowering, by 1-2 percentage points. Variation in toxicant levels was generally 1.5-1.7-fold higher in commercial cigarettes compared with 3R4F over the 10-month period, but increased up to 3.5-fold for analytes measured at ppb level. The potential error (2CV) associated with single-point-in-time sampling averaged ∼ 20%. Together, these data demonstrate that measurement of emissions from commercial cigarettes is associated with considerable variation for low-level toxicants. This variation would increase if the analyses were conducted in more than one laboratory.

Insights from analysis for harmful and potentially harmful constituents (HPHCs) in tobacco products

A total of 20 commercial cigarette and 16 commercial smokeless tobacco products were assayed for 96 compounds listed as harmful and potentially harmful constituents (HPHCs) by the US Food and Drug Administration. For each product, a single lot was used for all testing. Both International Organization for Standardization and Health Canada smoking regimens were used for cigarette testing. For those HPHCs detected, measured levels were consistent with levels reported in the literature, however substantial assay variability (measured as average relative standard deviation) was found for most results. Using an abbreviated list of HPHCs, statistically significant differences for most of these HPHCs occurred when results were obtained 4-6months apart (i.e., temporal variability). The assay variability and temporal variability demonstrate the need for standardized analytical methods with defined repeatability and reproducibility for each HPHC using certified reference standards. Temporal variability also means that simple conventional comparisons, such as two-sample t-tests, are inappropriate for comparing products tested at different points in time from the same laboratory or from different laboratories. Until capable laboratories use standardized assays with established repeatability, reproducibility, and certified reference standards, the resulting HPHC data will be unreliable for product comparisons or other decision making in regulatory science.

Aspects of the design protocol and the statistical methods for analysis of tar, nicotine and carbon monoxide yields in cigarette smoke that can affect the measurement variability within collaborative studies

Statistical principles described in ISO 5725-1 (1994) are a robust basis for evaluating cigarette smoke data from collaborative studies under the ISO 3308 machine smoking and for specifying the criteria for the removal of outlier data and determination of mean yields and their variability. However, the standard only provides recommendations on outlier removal that should be taken into account by experts who undertake data interpretation. The potential for over-interpretation of data from small numbers of laboratories is highlighted and recommendations made to deal with this possibility. Key variables to the statistical analysis, the number of cigarettes per replicate and replicates performed in each laboratory, the number of participating laboratories and the use of linear and rotary smoking machines in smoke collection, are identified and their relevance to obtaining robust data are considered. The statistical methods routinely used for data analysis from the ISO regime, are re-assessed for their suitability to analyse data obtained under the Canadian intense (CI) regime, where yield differences between linear and rotary smoking machines are found. This machine effect can lead to more outliers being detected and difficulties in outlier detection which may affect the provision of robust estimates of mean yields, repeatability and reproducibility.

TSNA levels in machine-generated mainstream cigarette smoke: 35 years of data

This paper characterizes historical and current tobacco specific nitrosamine (TSNA) levels in mainstream (MS) cigarette smoke of US commercial cigarettes. To conduct this analysis, we gathered 35 years of published data of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN) levels in MS cigarette smoke. We also assessed internal data of MS smoke NNK and NNN levels generated from various market monitoring initiatives and from control cigarettes used in a multi-year program for testing cigarette ingredients. In all, we analyzed machine smoking data from 401 cigarette samples representing a wide range of products and design characteristics from multiple manufacturers and market leaders. There was no indication that TSNA levels systematically increased in cigarette MS smoke over the 35-year analysis period. In particular, TSNA levels expressed as either per cigarette or normalized for tar suggest a downward trend in MS smoke over the past 10 years. The apparent downward trend in TSNA levels in MS smoke may reflect industry and agricultural community efforts to reduce levels of TSNAs in tobacco and cigarette smoke.

Intra- and inter-individual variability in urinary nicotine excretion and plasma cotinine in adult cigarette smokers

Urinary nicotine equivalents (NE) and plasma cotinine are widely used as a biomarker for exposure to tobacco products, but there is limited information on intra- and inter-individual variability in the literature. Data were gathered from 13 randomized controlled clinical studies sponsored by Philip Morris USA, with study durations between 2 and 8 days for the short term (ST) and 3-12 months for the long term (LT) studies. Coefficients of variation (CV) were compared and a linear mixed model was used to partition the total study variability into inter- and intra-individual variability. In the ST and LT studies respectively, the root-mean-square (RMS) intra-individual CV was 19% and 29% for NE (mg/24 h); 19% and 33% for NE (mg/cig) and 13% and 22% for plasma cotinine. The RSM inter-individual CV was 38% and 38% for NE (mg/24h), 25% and 32% for NE (mg/cig) and 38% and 37% for plasma cotinine, in ST and LT study, respectively. Intra-individual CV was smaller in ST studies than in LT studies, and was significantly less than inter-individual CV in ST studies. Daily cigarette consumption alone could not explain all the variability in NE and plasma cotinine. The variability estimates could be used for clinical study design of clinical and developing regulatory guidance.

Insights from a multi-year program designed to test the impact of ingredients on mainstream cigarette smoke toxicity

CONTEXT

Cigarette tobacco ingredients may alter the distribution of chemical constituents present in smoke. When considering the toxicological relevance of potential ingredient-related effects on chemical and biological measurements assessing cigarette smoke toxicity, it is critical to understand the intrinsic variability of tobacco and cigarette smoke that is influenced by the environmental conditions during growing, agricultural practices during preparation, cigarette manufacturing tolerances, and stability of the assay methods.

OBJECTIVE

To understand possible effects of ingredients on cigarette smoke toxicity, various chemical and biological endpoints were measured in smoke from experimental cigarettes (added ingredient) to the intrinsic variability of control cigarettes (no added ingredient).

MATERIALS AND METHODS

Data were collected during a multi-year program testing a variety of cigarette ingredients from several chemical classes. Chemical analysis of mainstream cigarette smoke,and biological procedures (Salmonella mutagenicity, cytotoxicity, and smoke inhalation) were performed using validated and controlled laboratory methods. The within-study and temporal variation of control cigarettes manufactured in parallel with experimental cigarettes was calculated and used to measure intrinsic variability.

RESULTS

The overwhelming majority of data generated from experimental cigarettes fell within the experiment variability represented by the pooled standard error of the entire multi-year dataset for the control cigarettes.

CONCLUSION

The results of this evaluation add to a growing body of the literature regarding a weight of evidence assessment of cigarette ingredient toxicity. When assessed against the variability of assay methodology, natural agricultural change, and manufacturing control, the ingredients studied here demonstrated little relevant influence on the mainstream cigarette smoke toxicity endpoints measured.

Machine-smoking studies of cigarette filter color to estimate tar yield by visual assessment and through the use of a colorimeter

This paper explores using the intensity of the stain on the end of the filter ("filter color") as a vehicle for estimating cigarette tar yield, both by instrument reading of the filter color and by visual comparison to a template. The correlation of machine-measured tar yield to filter color measured with a colorimeter was reasonably strong and was relatively unaffected by different puff volumes or different tobacco moistures. However, the correlation of filter color to machine-measured nicotine yield was affected by the moisture content of the cigarette. Filter color, as measured by a colorimeter, was generally comparable to filter extraction of either nicotine or solanesol in its correlation to machine-smoked tar yields. It was found that the color of the tar stain changes over time. Panelists could generally correctly order the filters from machine-smoked cigarettes by tar yield using the intensity of the tar stain. However, there was considerable variation in the panelist-to-panelist tar yield estimates. The wide person-to-person variation in tar yield estimates, and other factors discussed in the text could severely limit the usefulness and practicality of this approach for visually estimating the tar yield of machine-smoked cigarettes.

Review: Is lung inflammation associated with microbes and microbial toxins in cigarette tobacco smoke?

Chronic inflammation that has been observed for malignant and non-neoplastic lung diseases of smokers has been attributed to the numerous and diverse particulate ('tar')-phase and gas-phase chemicals in mainstream smoke, most of which arise from the burning of tobacco. The primary cell-mediator of lung inflammation is the macrophage. Most probably, inflammation is promoted also from some of the more than 50 other cell types of the lung. Cured tobacco in diverse types of cigarettes is known to harbor a plethora of bacteria (Gram-positive and Gram-negative), fungi (mold, yeast), spores, and is rich in endotoxin (lipopolysaccharide). Reviewed herein are recent observations of the authors' team and other investigators that support the hypothesis that lung inflammation of long-term smokers may be attributed in part to tobacco-associated bacterial and fungal components that have been identified in tobacco and tobacco smoke.

New insights into the formation of volatile compounds in mainstream cigarette smoke

A sampling system has been set up to monitor a group of volatile smoke analytes (nitric oxide, acetaldehyde, acetone, benzene, toluene, 1,3 butadiene, isoprene and carbon dioxide) from mainstream cigarette smoke on a puff-resolved basis. The system was able to record gas evolution profiles during puffing and interpuff periods without interruption (e.g. taking clearing puffs). Gas phase smoke analytes were sampled as close to the mouth end of the cigarette filter as possible in order to minimise any dead volume effect. The results revealed that, for some volatile species, a significant fraction (e.g. up to 30% for benzene) in the cigarette mainstream smoke had been generated during the preceding smoulder period. These species were trapped or absorbed within the cigarette rod and then subsequently eluted during the puff. The identification of the two sources of the mainstream smoke, a smouldering source and a puffing source, has not been reported before. The observation contributes to the fundamental knowledge of the cigarette smoke formation and may have implications on wider smoke chemistry and associated effects.

Nasal olfactory epithelial lesions in F344 and SD rats following 1- and 5-day inhalation exposure to naphthalene vapor

The exposure-response relationship and threshold for nasal epithelial effects of naphthalene (NP) vapor in F344 and SD rats were investigated in 1-day (6 hours) and 5-day (6 h/d) studies at concentration ranges of 0 to 30 ppm. Lesions related to 1-day exposure were predominantly necrosis of the olfactory epithelium (OE). The severity of OE lesions was concentration dependent and ranged from minimal (< or =1 ppm) to marked (10-30 ppm). In the 5-day study, degeneration of OE was observed in both strains, both sexes, with increasing incidence and severity that correlated with concentration. The epithelial degeneration lesion was minimal to moderate in severity. At 0.1 ppm, minimal OE lesions were observed in female SD rats only (20% incidence). Animals exposed to 10 ppm NP followed by 14 days without exposure also had OE lesions, but of lower severity, showing evidence of good recovery. In both studies, differences between sex or strain were not remarkable.