Anita R. Iskandar, Filippo Zanetti, Diego Marescotti, Bjorn Titz, Alain Sewer, Athanasios Kondylis, Patrice Leroy, Vincenzo Belcastro, Laura Ortega Torres, Stefano Acali, Shoaib Majeed, Sandro Steiner, Keyur Trivedi, Emmanuel Guedj, Celine Merg, Thomas Schneider, Stefan Frentzel, Florian Martin, Nikolai V. Ivanov, Manuel C. Peitsch, Julia Hoeng
Philip Morris International R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
Previous experimental setups shows the effects of e-liquids on cell viability (first layer), followed by investigating the potential mechanisms of toxicity elicited by e-liquids (second layer) and finally assessing the impacts of aerosols (third layer). In this present work shows how the three-layer framework is leveraged to evaluate the potential toxicity and biological effects of the MESH Classic Tobacco and Base e-liquids/aerosols compared with those of 3R4F CS.
We previously proposed a systems toxicology framework for in vitro assessment of e-liquids. The framework starts with the first layer aimed at screening the potential toxicity of e-liquids, followed by the second layer aimed at investigating the toxicity-related mechanism of e-liquids, and finally, the third layer aimed at evaluating the toxicity-related mechanism of the corresponding aerosols. In this work, we applied this framework to assess the impact of the e-liquid MESH Classic Tobacco and its aerosol compared with that of cigarette smoke (CS) from the 3R4F reference cigarette. In the first layer, we evaluated the cytotoxicity profile of the MESH Classic Tobacco e-liquid (containing humectants, nicotine, and flavors) and its Base e-liquid (containing humectant and nicotine only) in comparison with total particulate matter (TPM) of 3R4F CS using primary bronchial epithelial cell cultures. In the second layer, the same culture model was used to explore changes in specific markers using high-content screening assays to identify potential toxicity-related mechanisms induced by the MESH Classic Tobacco and Base e-liquids beyond cell viability in comparison with the 3R4F CS TPM-induced effects. Finally, in the third layer, we compared the impact of exposure to the MESH Classic Tobacco or Base aerosols with 3R4F CS using human organotypic air–liquid interface buccal and small airway epithelial cultures. The results showed that the cytotoxicity of the MESH Classic Tobacco liquid was similar to the Base liquid but lower than 3R4F CS TPM at comparable nicotine concentrations. Relative to 3R4F CS exposure, MESH Classic Tobacco aerosol exposure did not cause tissue damage and elicited lower changes in the mRNA, microRNA, and protein markers. In the context of tobacco harm reduction strategy, the framework is suitable to assess the potential-reduced impact of electronic cigarette aerosol relative to CS.