Electronic cigarette aerosol induces significantly less cytotoxicity than Tobacco smoke

Abstract

Electronic cigarettes (E-cigarettes) are a potential means of addressing the harm to public health caused by tobacco smoking by offering smokers a less harmful means of receiving nicotine. As e-cigarettes are a relatively new phenomenon, there are limited scientifiata on the longer-term health effects of theise. This study describes a robust in vitro method for assessing the cytotoxic response o-cigarette aerosols that can bffectively compared with conventional cigarette smoke. This was measured using the regulatory accepted Neutral Red Uptake assay modified for air-liquid interface (ALI) exposures. An exposure system, comprising a smoking machine, traditionally used for in vitro tobacco smokxposure assessments, was adapted fose with e-cigarettes to expose human lung epithelial cells at the ALI. Dosimetric analysis methods using real-time quartz crystal microbalances for mass, and post-exposure chemical analysis for nicotine, wermployed to detect/distinguish aerosoilutions from a reference Kentucky 3R4F cigarette and two commercially availabl-cigarettes (VypStick and ePen). ePen aerosol induced 97%, 94% and 70% less cytotoxicity than 3R4F cigarette smokased on matched EC50values aifferenilutions (1:5 vs. 1:153 vol:vol), mass (52.1 vs. 3.1 μg/cm2) and nicotine (0.89 vs. 0.27 μg/ cm2), respectively. Tesoses where cigarette smoke and e-cigarette aerosol cytotoxicity were observed are comparable with calculated daily doses in consumers. Such experiments could form thasis of a larger package of work including chemical analyses, in vitro toxicology tests and clinical studies, to help assess the safety of current and next generation nicotine and tobacco products.