The paradox of the safer cigarette: understanding the pulmonary effects of electronic cigarettes
Kassandra Allbright, J. Villandre, Laura E. Crotty Alexander, Michael S. Zhang, Kambez H. Benam, John Evankovich, Mélanie Königshoff, Divay Chandra
Abstract
Electronic cigarette (e-cigarette) use continues to rise globally. E-cigarettes have been presented as safer alternatives to combustion cigarettes that can mitigate the harm associated with tobacco products; however, the degree to which e-cigarette use itself can lead to morbidity and mortality is not fully defined. Herein we describe how e-cigarettes function; discuss the current knowledge of the effects of e-cigarette aerosol on lung cell cytotoxicity, inflammation, antipathogen immune response, mucociliary clearance, oxidative stress, DNA damage, carcinogenesis, matrix remodelling and airway hyperresponsiveness; and summarise the impact on lung diseases, including COPD, respiratory infection, lung cancer and asthma. We highlight how the inclusion of nicotine or flavouring compounds in e-liquids can impact lung toxicity. Finally, we consider the paradox of the safer cigarette: the toxicities of e-cigarettes that can mitigate their potential to serve as a harm reduction tool in the fight against traditional cigarettes, and we summarise the research needed in this underinvestigated area.