LC/MS analysis of three-dimensional model cells exposed to cigarette smoke or aerosol from a novel tobacco vapor product

Chemical and in vitro toxicological comparison of emissions from a heated tobacco product and the 1R6F reference cigarette

It has previously been found that, compared with cigarette smoke, the aerosols generated by heated tobacco products contain fewer and lower harmful and potentially harmful constituents (HPHCs) and elicit lower biological activity in in vitro models and lower smoking-related exposure biomarker levels in clinical studies. It is important to accumulate such scientific evidences for heated tobacco products with a novel heating system, because different heating system may affect the quantitative aspect of the amount of HPHCs and the qualitative aspect of the biological activity of the aerosol generated. Here, the chemical properties of, and toxicological responses to aerosols emitted by DT3.0a, a new heated tobacco product with a novel heating system, and cigarette smoke (CS) were compared, using chemical analyses, in vitro battery (standardized genotoxicity and cytotoxicity) assays, and mechanistic (ToxTracker and two-dimensional cell culture) assays. Regular- and menthol-flavored DT3.0a and standard 1R6F reference cigarettes were tested. Selected HPHC yields were lower in DT3.0a aerosol than 1R6F CS. The genotoxicity-related assays indicated that DT3.0a aerosol was not genotoxic, regardless of metabolic activation. The other biological assays indicated that less cytotoxicity induction and oxidative stress response were elicited by DT3.0a aerosol compared with 1R6F CS. Similar results were found for both regular and menthol DT3.0a. Like previous reports for heated tobacco products with other heating systems, the results of this study indicated that DT3.0a aerosols have chemical and biological properties less likely to be harmful than 1R6F CS.

Donor-to-donor variability of a human three-dimensional bronchial epithelial model: A case study of cigarette smoke exposure

Three-dimensional (3D) cultured primary cells are used to predict the toxicity of substances towards humans because these 3D cultures closely mimic the physiological architecture of tissues. Nonetheless, it is important to consider primary-cell-specific variability for endpoint selection and appropriate evaluation of toxicity because donor-dependent characteristics may be retained even in in vitro cell cultures. In this report, 3D differentiated bronchial epithelial cells from three donors were used to investigate donor-to-donor variability, with an aqueous extract of cigarette smoke (CS) used as the test substance. Ciliary function, cytokine secretion, and histopathology, which are affected by CS, were examined, and transcriptomic analysis was also performed. The results revealed that interleukin-8 secretion and oxidative stress-related gene expression were consistently altered for all donors; however, their amplitudes varied. Moreover, one of the donors showed unique responses to CS, suggesting that this donor was an outlier. This donor showed intrinsic differences in histology, cytokine secretion, and gene expression profile. Such donors may help evaluate potential toxicological concerns and aid our understanding of disease pathogenesis. Conversely, these donors may confound toxicological assessment and endpoint selection. Fit-for-purpose handling of inter-donor variability is warranted.