Effects of volcanic fumaroles on large and distal airway epithelial homeostasis

Airway epithelium exerts an active role in coordinating innate and adaptive immune responses upon external insult exposure. The potential adverse health effects following exposure to airborne products of volcanic activity in the settings of airway diseases, inflammation, and injury of airway epithelial cells are largely unknown. The present study was aimed at assessing the effects of a volcanic fumarole condensate(F5HT;HT=high temperature) from Vulcano Island (Eolie Island) on large (16HBE) and distal (A549) airway epithelial cell lines. Gas chromatography was used to analyze chemical composition of fumarole samples. The selected cell lines were exposed to different concentrations of F5HT condensate (2, 5 and 10%) for 24h and then assessed for MTS (to assess cell metabolism/cell viability),for AnnexinV/Propidium Iodide (to assess cell apoptosis/cell necrosis) and for the expression by flow cytometry of IL-33, an allarmin able to support T helper 2 responses. Fumarole samples taken from the same fumarole at different times contained: water vapor from 70-97%, CO2 from 3-30%, acid gases (H2S,SO2,HCl,HF) around 1% and trace elements of He,Ar, H2,N2,CO. F5HT at 2% and 5% did not significantly affect cell viability/metabolism, cell apoptosis /cell necrosis or IL-33 expression in both 16HBE and A549 cell lines. Differently, in both cell lines the exposure to F5HT at 10% induced a significant decrease of the absorbance in MTS assay and an evident intracellular increase in IL-33 expression without inducing cell necrosi/cell apoptosis. Data herein reported describe for the first time molecular events promoted in large/distal airway epithelial cells exposed to volcanic fumaroles.