Research progress on the effect of neutrophil elastase and its inhibitors in respiratory diseases

Neutrophil elastase is a serine protease secreted by neutrophils that plays a crucial role in the onset and progression of various respiratory diseases. The imbalance between neutrophil elastase and its endogenous inhibitors can contribute to the onset and progression of respiratory diseases such as chronic obstructive pulmonary disease, cystic fibrosis, bronchiectasis, and acute respiratory distress syndrome. The excessive release of neutrophil elastase contributes to multiple pathophysiological processes, such as disruption of the alveolar-capillary barrier, oxidative stress and inflammatory responses, autophagy, and apoptosis. The use of neutrophil elastase as a biomarker in disease assessment and prognosis prediction as well as the potential of neutrophil elastase inhibitors in clinical treatment have shown broad application prospects. Neutrophil elastase inhibitors have certain limitations such as off-target effects, poor lung bioavailability, cost considerations, and variability in patient responses. This article reviews the literature on neutrophil elastase and its inhibitors in the field of respiratory diseases, aiming to provide new insights into the diagnosis and treatment of related respiratory diseases.