RT Journal Article SR Electronic T1 Azithromycin prevents airway epithelial barrier dysfunction induced by sulphur dioxide inhalation JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 4782 DO 10.1183/13993003.congress-2020.4782 VO 56 IS suppl 64 A1 Jennifer Kricker A1 Thorarinn Gudjonsson A1 Ari Jon Arason A1 Jon Pétur Joelsson A1 Bryndis Valdimarsdottir A1 Fridrik Runar Gardarsson A1 Clive Page A1 Fredrik Lehmann A1 Saevar Ingthorsson YR 2020 UL http://erj.ersjournals.com/content/56/suppl_64/4782.abstract AB Azithromycin (AZM) is a macrolide which is effective in the treatment of several airway diseases induced by bacterial or environmental insults. We have previously shown barrier enhancing effects of AZM on airway epithelium (AE). In order to analyze barrier enhancing effects of AZM in vivo we have challenged mice with inhalation of sulphur dioxide (SO2) to induce AE barrier failure. Mice were exposed to 50-400 ppm SO2 gas for 0.5-4 hours and monitored up to 7 days before bronchoalveolar lavage fluid (BALF) collection and analysis. AE barrier function was evaluated by measuring human serum albumin (HSA) leakage into BALF. HSA was injected into the tail vein of mice one hour prior to sacrifice, BALF was then harvested and HSA concentration measured by ELISA. AZM administered prior to exposure to SO2 resulted in a reduction of HSA, indicating protective effects of AZM on the AE. Increased intracellular vacuolization and lamellar body (LB) formations were seen in AZM treated animals. Glutathione-S-Transferases (GSTs), a class of enzymes that help maintain cellular integrity, were reduced in SO2 treated mice. Mass spectrometry analysis of BALF from SO2 exposed mice revealed that treating the mice with AZM lead to higher concentrations of GSTs in BALF, suggesting a link between AZM treatment and a reduction in GST concentration. In conclusion, we demonstrated a protective effect of AZM on the barrier integrity of the AE, possibly through stabilizing the intracellular microenvironment and by facilitating formation of LBs, providing further insight to its effectiveness in the treatment of airway diseases.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 4782.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).