Project description:As part of current harm reduction strategies, candidate modified risk tobacco products (MRTP)s are developed to offer adult smokers who want to continue using tobacco products as an alternative to cigarettes while potentially reducing individual risk and population harm compared to smoking cigarettes. One of these candidate MRTPs is the Tobacco Heating System (THS) 2.2 which does not burn tobacco, but instead heats it, thus producing significantly reduced levels of harmful and potentially harmful constituents (HPHC)s compared with combustible cigarettes (CC). The assessment of MRTPs against combustible cigarettes requires the establishment of exposure-response markers. Biomarkers derived from blood offer for the general population a less invasive alternative than sampling the primary site, such as the airways. Various diseases and exposures, including cigarette smoke, have been shown to alter the molecular profile of the blood. Leveraging this fact, a whole blood derived gene signature that can distinguish current smokers from either non-smokers or former smokers with high specificity and sensitivity was previously reported. Four controlled, parallel randomized groups, open-label clinical studies were conducted with subjects randomized to three groups: (1) switching from CCs to THS2.2 (or its mentholated version, respectively); (2) continuous use of CC; or (3) smoking abstinence. These studies had an investigational period of five days in confinement which was followed by an 85 day ambulatory period for two of them. By measuring biomarkers of exposure to selected HPHCs, these studies showed a consistent reduced exposure in subjects that either stopped smoking or switched to THS2.2 (including mentholated version), compared with subjects who continued smoking their own cigarettes at both day 5 and at day 90. To complement the classical exposure measurements, we tested the small signature consisting of only 11 genes on the blood transcriptome of subjects enrolled in the clinical studies. We show that in all four clinical studies tested, the signature scores were consistently reduced in subjects that either stopped smoking or switched to THS2.2 compared with subjects who continued smoking their conventional tobacco products at both day 6 and at day 91.

Project description:In vitro toxicology approaches have evolved, from a focus on the molecular changes within a cell to understanding of toxicity-related mechanisms that simulate the in vivo environment. The recent development of three dimensional (3-D) organotypic nasal epithelial culture models offer a physiologically robust system for studying the effects of exposure through inhalation. Exposure to cigarette smoke (CS) is associated with nasal inflammation; thus the nasal epithelium is relevant for evaluating the pathophysiological impact of CS exposure. The present study investigated further the relevancy and application of in vitro human 3-D nasal epithelial culture models for toxicological assessment of inhalation exposure. The biological impact was assessed following exposure to aerosol generated from a candidate modified risk tobacco product (MRTP), the Tobacco Heating System (THS) 2.2, as compared with smoke generated from reference cigarette 3R4F using an in vitro human 3-D nasal epithelial cultures. A series of experimental repetitions where multiple doses of the aerosol and smoke were applied, were conducted to obtain reproducible measurements and reliable observations to understand the cellular/molecular changes that occur following exposure. Aligned with the 3Rs Strategy and the Vision-and-Strategy of the Toxicity Testing in the 21st Century, this study implemented a systems toxicology approach and found that for all tested concentrations, the impact of 3R4F smoke was considerably greater than that of THS2.2 aerosol in terms of cytotoxicity levels, alterations in the tissue morphology, secretion of pro-inflammatory mediators, impaired ciliary function, and increased perturbed transcriptomes and miRNA expression profiles. In addition, to evaluate further the possible adverse effects of THS2.2 aerosol, a dose range assessment was conducted. A broader range of THS2.2 concentrations were exposed to the nasal cultures. Various dilutions of THS2.2 were applied to the cultures using the VitrocellÂ® 24/48 exposure system, corresponding to the concentrations of nicotine between 0.15 mg/L and 1.79 mg/L

Dataset Information

Identification of gene expression signature for cigarette smoke exposure response--from man to mouse.

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