The application of in vitro cellular assays for analysis of electronic cigarettes impact on the airway

Electronic (e)-cigarettes have been marketed for more than a decade as an alternative to conventional cigarettes. Their popularity and use among adolescents have grown significantly during recent years. While e-cigarettes do not release carcinogenic aromatic hydrocarbons, they can generate reactive carbonyls and radicals during the heating process in vitro. Emphasis has been placed in recent studies to introduce more rigorous and physiologically relevant in vitro models to characterise the toxicological profile of e-cigarettes. However, significant challenges are present due to difficulties for the developed systems to fully represent the in vivo inhalation settings. Furthermore, research protocols that fail to simulate the characteristics of e-cigarettes can affect the findings of in vitro studies. This review will illustrate the status quo of e-cigarette assays in vitro, discussing the various cellular assays used for evaluating the safety profile of e-cigarettes. Future directions will also be provided to better assist the scientific community in interpreting the health risks of e-cigarettes. [Display omitted]