title: Influence of E-smoking liquids on human periodontal ligament fibroblasts.
abstract: BACKGROUND
  Over the last years, electronic cigarettes (ECs) have become more popular, particularly in individuals who want to give up smoking tobacco. The aim of the present study was to assess the influence of the different e-smoking liquids on the viability and proliferation of human periodontal ligament fibroblasts.
  
  
  METHODS
  For this study six test solutions with components from ECs were selected: lime-, hazelnut- and menthol-flavored liquids, nicotine, propylene glycol, and PBS as control group. The fibroblasts were incubated up to 96 h with the different liquids, and cell viability was measured by using the PrestoBlue® reagent, the ATP detection and the migration assay. Fluorescence staining was carried out to visualize cell growth and morphology. Data were statistically analyzed by two-tailed one-way ANOVA.
  
  
  RESULTS
  The cell viability assay showed that the proliferation rates of the cells incubated with nicotine or the various flavored liquids of the e-cigarettes were reduced in comparison to the controls, though not all reductions were statistically significant. After an incubation of 96 h with the menthol-flavored liquid the fibroblasts were statistically significant reduced (p < 0.001). Similar results were found for the detection of ATP in fibroblasts; the incubation with menthol-flavored liquids (p < 0.001) led to a statistically significant reduction. The cell visualization tests confirmed these findings.
  
  
  CONCLUSIONS
  Within its limits, the present in vitro study demonstrated that menthol additives of e-smoking have a harmful effect on human periodontal ligament fibroblasts. This might indicate that menthol additives should be avoided for e-cigarettes.
authors.forename: Ines
authors.initials: I
authors.lastname: Willershausen
authors.forename: Thomas
authors.initials: T
authors.lastname: Wolf
authors.forename: Veronika
authors.initials: V
authors.lastname: Weyer
authors.forename: Robert
authors.initials: R
authors.lastname: Sader
authors.forename: Shahram
authors.initials: S
authors.lastname: Ghanaati
authors.affiliation: Department for Operative Dentistry, University Medical Center of the Johannes Gutenberg University Mainz, Augustusplatz 2, 55131 Mainz, Germany. willersh@uni-mainz.de.
authors.forename: Brita
authors.initials: B
authors.lastname: Willershausen
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D066300:Electronic Nicotine Delivery Systems; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D008610:Menthol / Q000494:pharmacology*; D009538:Nicotine / Q000494:pharmacology*; D010513:Periodontal Ligament / Q000166:cytology* / Q000187:drug effects; D012907:Smoking
chemical_list: D008610:Menthol; D009538:Nicotine