title: Evaluation of E-cigarette liquid vapor and mainstream cigarette smoke after direct exposure of primary human bronchial epithelial cells.
abstract: E-cigarettes are emerging products, often described as "reduced-risk" nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact  module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5-8 times lower and the oxidative stress levels 4.5-5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user.
authors: Cultex Laboratories GmbH, Feodor-Lynen-Str. 21, 30625 Hannover, Germany. s.scheffler@cultex-laboratories.com.
authors: Stefanie
authors: S
authors: Scheffler
authors: Cultex Laboratories GmbH, Feodor-Lynen-Str. 21, 30625 Hannover, Germany. h.dieken@cultex-laboratories.com.
authors: Hauke
authors: H
authors: Dieken
authors: Cultex Laboratories GmbH, Feodor-Lynen-Str. 21, 30625 Hannover, Germany. o.krischenowski@cultex-laboratories.com.
authors: Olaf
authors: O
authors: Krischenowski
authors: Institute of Pathology, KRH Klinikum Nordstadt, Haltenhoffstr. 41, 30167 Hannover, Germany. christine.foerster@krh.eu.
authors: Christine
authors: C
authors: Förster
authors: Department of Thoracic Surgery, Bielefeld Evangelical Hospital, Burgsteig 13, 33617 Bielefeld, Germany. detlev.branscheid@evkb.de.
authors: Detlev
authors: D
authors: Branscheid
authors: Cultex Laboratories GmbH, Feodor-Lynen-Str. 21, 30625 Hannover, Germany. m.aufderheide@cultex-laboratories.com.
authors: Michaela
authors: M
authors: Aufderheide
mesh_terms: D001980:Bronchi / Q000187:drug effects*; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D004847:Epithelial Cells / Q000187:drug effects*; D006801:Humans; D009538:Nicotine / Q000009:adverse effects*; D012906:Smoke / Q000009:adverse effects*
chemical_list: D012906:Smoke; D009538:Nicotine