Airway epithelial barrier integrity: an emerging treatable trait in asthma management

The airway epithelium not only acts as a physical barrier between the environment and the host, but also functions as an active immunological interface, facilitating crosstalk between the epithelial cells, immune cells and the microbiome aimed at protecting the host. Therefore, maintaining airway epithelial barrier integrity and its functions is crucial for prevention of chronic inflammatory airway diseases, such as allergy, asthma and chronic obstructive pulmonary disease. The potential to restore the epithelial barrier by therapeutic interventions has increasingly gained interest over recent years. As part of their disease-modifying properties, various treatment modalities including small molecule drugs, biologics, bronchial thermoplasty and allergen immunotherapy, showed beneficial effects on epithelial barrier integrity in select patient populations. In this review, we summarize current knowledge, discuss recent evidence of therapeutic interventions on restoring epithelial barrier function and highlight unmet needs and future research directions.