Azithromycin Maintains Barrier Integrity In A Cell Model Of Ventilator Induced Lung Injury

Aim: We recently developed a cell culture model, the Cyclical Pressure Air-liquid interface Device (CPAD), that mimics the disruption of the lung epithelial barrier and the increased inflammatory response associated with ventilator-induced lung injury (VILI)1. Azithromycin (AZM) is a broad-spectrum antibiotic that has also been shown to have anti-inflammatory and immunomodulatory functions unrelated to its antibacterial activity. The mechanisms behind these beneficial effects are not yet fully elucidated. The aim of this study was to analyze the effect of cyclical mechanical stress on AZM pre- treated lung epithelial cell lines. Methods: Bronchial (VA10) and alveolar (hAELVi) derived cell lines were cultured in air-liquid interfase conditions and mechanically stressed in the CPAD (peak pressure 27 cm H2O, positive end-expiratory pressure 5 cm H2O, 16 cycles/ min) with and without AZM pre-treatment and the effect analyzed. Results: Immunostainings and electron microscope imaging showed that barrier integrity of the epithelium was compromised by cyclical stress but maintained when cells were pre-treated with AZM. Lamellar body formations were also revealed in AZM pre-treated cells. RNA sequencing and gene expression analysis showed that cyclical stress resulted in an increased immune response that was attenuated by AZM pre-treatment. Conclusion: These results suggest that AZM directs lung epithelial cells towards epidermal differentiation and has barrier protective and immunomodulatory effects, attenuating the inflammatory response, during cyclical mechanical stress and might therefore be lung protective during mechanical ventilation. 1 Joelsson JP. ALTEX doi:10.14573/altex.1901182