title: Cytotoxicity and apoptosis induction by e-cigarette fluids in human gingival fibroblasts.
abstract: OBJECTIVE
  Electronic cigarettes (e-cigarettes) are generally acknowledged as a safer alternative to the use of combusted tobacco products. Nevertheless, there are increasing conflicting claims concerning the effect of these novel industrial products on the health of e-cigarettes users. The aim of this work was to investigate the effects of the liquids of e-cigarettes on human gingival fibroblasts (HGFs) and to compare the effects of nicotine-containing fluid to the fluid itself.
  
  
  METHODS
  HGFs were treated with different concentrations (0-5 mg/mL) of fluids of e-cigarettes for different times (0-72 h) and cytotoxicity was analyzed by MTT assay. Fluids were administered also after being vaped (e.g., warmed into the cartomizer). Apoptosis occurrence and Bax expression were evaluated by flow cytometry; ROS production was analyzed by fluorescence optical microscopy.
  
  
  RESULTS
  Both nicotine-containing and nicotine-free fluids induced an increased ROS production after 24 h, along with an increased Bax expression, followed by apoptosis occurrence after 48 h of exposure.
  
  
  CONCLUSIONS
  The cytotoxicity exerted on HGFs by e-cigarettes fluids is not entirely ascribable to nicotine. Since the e-cigarettes are advertised as a safer alternative to traditional ones, especially for the possibility of "smoking" nicotine-free fluids, further studies are necessary to clarify the mechanism involved in the occurrence of cytotoxicity exerted by such compounds.
  
  
  CONCLUSIONS
  Our results suggest a role for e-cigarette fluids in the pathogenesis of oral diseases, such as periodontitis.
authors.affiliation: Department of Pharmacy, G. d'Annunzio University, Chieti-Pescara, Via dei Vestini, 31, 66100, Chieti Scalo (CH), Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Sancilio
authors.affiliation: Department of Pharmacy, G. d'Annunzio University, Chieti-Pescara, Via dei Vestini, 31, 66100, Chieti Scalo (CH), Italy. marialucia.gallorini@unich.it.|Department of Operative Dentistry and Periodontology, University Hospital Regensburg, University of Regensburg, Regensburg, Germany. marialucia.gallorini@unich.it.
authors.forename: Marialucia
authors.initials: M
authors.lastname: Gallorini
authors.affiliation: Department of Pharmacy, G. d'Annunzio University, Chieti-Pescara, Via dei Vestini, 31, 66100, Chieti Scalo (CH), Italy.
authors.forename: Amelia
authors.initials: A
authors.lastname: Cataldi
authors.affiliation: Department of Pharmacy, G. d'Annunzio University, Chieti-Pescara, Via dei Vestini, 31, 66100, Chieti Scalo (CH), Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: di Giacomo
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D005347:Fibroblasts / Q000187:drug effects*; D005434:Flow Cytometry; D005881:Gingiva / Q000166:cytology* / Q000187:drug effects*; D006801:Humans; D008856:Microscopy, Fluorescence; D017382:Reactive Oxygen Species / Q000378:metabolism; D012307:Risk Factors; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein
keywords: Apoptosis; Bax; Cytotoxicity; Human gingival fibroblast; Reactive oxygen species; e-cigarette