Background
Information about the harmful effects of vaping is sparse and inconsistent, therefore, since the use of electronic cigarettes (e-CIGs) has become increasingly popular as a tool to limit tobacco smoking, it is urgent to establish the safety or the toxicity of the liquid vaporized by the atomizer of the commercial e-CIGs.
Methods
Skin (HaCaT) and lung (A549) cells, the main targets of cigarette smoke, were exposed to e-CIG vapor (e-CIG Mini Touch T-Fumo T-TEX) and cigarette smoke (UK research cigarette) in a smoke chamber in vitro. The cytotoxic effect of the exposure was analyzed in both cell types by ultrastructural morphology, Trypan Blue exclusion test and LDH assay. In addition, pro-inflammatory cytokines were measured in culture medium by the Bio-Plex cytokine assay kit.
Results
The cytotoxic components of e-CIG were restrained to the flavoring compound and, to a lesser extent, to nicotine and their effects were comparable to that of cigarette smoke. Humectants alone exhibited no cytotoxicity but induced the release of cytokines and pro-inflammatory mediators, mainly in keratinocytes.
Conclusions
Based on our results, we can state that e-CIG vapors exposure is not completely harmless, although far less toxic than CS. In fact, besides the deleterious effect of flavor and nicotine, even the humectants alone are able to evocate some adverse cellular events, such as enhanced cytokines release. This study will hopefully promote the development of truly innocuous e-CIGs to help people quit smoking.