The effects of E-cigarettes on pulmonary inflammation and inflammasome activation

A549 epithelial cells, THP-1 macrophages and primary macrophages isolated from smoking and non-smoking individuals were treated with E-liquid, E-vapours and inflammasome stimuli. <br><br>E -vapours and liquids were not cytotoxic to macrophages or epithelial cells. E-vapours also reduced IL-8 expression from resting epithelial cells and macrophages and from TNFĮ activated epithelial cells. In relation to inflammasome activation, E-vapours acted as a signal 2 DAMP in LPS primed macrophages but not in epithelial cells.

Conversely, when macrophages were stimulated with classical inflammasome activators, LPS and Nigericin, the simultaneous addition of E-vapour with these signals reduced inflammasome activation. Analysis of BAL from E-cigarette users and smokers after LPS inhalation showed a similar inflammatory profile as measured by inflammatory cytokine and acute phase protein content. These data highlight that vaporisation of E-liquid produces vapours that are not benign to human cells and can cause inflammatory dysregulation.