Anatomical and histopathological approaches to asthma phenotyping

Small airways dysfunction in severe asthma: Current treatment approaches and future directions

Severe asthma is a significant health concern due to its association with higher mortality rates, reduced quality of life, and increased healthcare costs. These challenges make it a persistent issue for both clinicians and researchers. The small airways, defined as distal airways with a diameter of less than 2 mm and comprising 98.8% of the total lung volume, play a significant role in airway resistance in individuals with asthma. Recent studies demonstrated that small airways dysfunction is found in all asthma severity levels, but it is most pronounced in severe asthma, and greater small airways dysfunction severity correlates with poorer asthma control and a higher frequency of exacerbations. Therefore, therapies aimed at targeting small airways dysfunction are essential for effective asthma management, especially in severe asthma.

Network pharmacology analysis and experimental validation of Xiao-Qing-Long-Tang's therapeutic effects against neutrophilic asthma

BACKGROUND

Xiao-Qing-Long-Tang (XQLT), a classical Chinese herbal medicine formula, has been extensively used for allergic asthma treatment. However, there is limited research on its anti-inflammatory effects and mechanisms specifically in neutrophilic asthma (NA).

PURPOSE

This study aims to investigate the potential therapeutic effects of XQLT against NA using a combination of network pharmacology and experimental validation.

STUDY DESIGN

By utilizing traditional Chinese medicine and disease databases, we constructed an XQLT-asthma network to identify potential targets of XQLT for NA. In the experimental phase, we utilized an ovalbumin (OVA)/lipopolysaccharide (LPS)-induced model for neutrophilic asthma and examined the therapeutic effects of XQLT.

RESULTS

Our research identified 174 bioactive components within XQLT and obtained 140 target genes of XQLT against asthma. Functional enrichment analysis revealed that these target genes were primarily associated with inflammation and cytokines. In the experimental validation, mice induced with OVA-LPS showcased eosinophilic and neutrophilic cell infiltration in peri-bronchial areas, elevated levels of IL-4 and IL-17 in both serum and lung, increased percentages of Th2 and Th17 cells in the spleen, as well as elevated levels of CD11b+ and CD103+ dendritic cells (DCs) within the lung. Treatment with XQLT effectively reduced IL-4 and IL-17 levels, decreased the percentages of Th2, Th17, CD11b+, and CD103+ DCs, and improved inflammatory cell infiltrations in lung tissues. These findings serve as a foundation for the potential clinical application of XQLT in neutrophilic asthma.

Mast Cell Tryptase Promotes Airway Remodeling by Inducing Anti-Apoptotic and Cell Growth Properties in Human Alveolar and Bronchial Epithelial Cells

Bronchial and alveolar remodeling and impaired epithelial function are characteristics of chronic respiratory diseases. In these patients, an increased number of mast cells (MCs) positive for serine proteases, tryptase and chymase, infiltrate the epithelium and alveolar parenchyma. However, little is known regarding the implication of intraepithelial MCs on the local environment, such as epithelial cell function and properties. In this study, we investigated whether MC tryptase is involved in bronchial and alveolar remodeling and the mechanisms of regulation during inflammation. Using novel holographic live cell imaging, we found that MC tryptase enhanced human bronchial and alveolar epithelial cell growth and shortened the cell division intervals. The elevated cell growth induced by tryptase remained in a pro-inflammatory state. Tryptase also increased the expression of the anti-apoptotic protein BIRC3, as well as growth factor release in epithelial cells. Thus, our data imply that the intraepithelial and alveolar MC release of tryptase may play a critical role in disturbing bronchial epithelial and alveolar homeostasis by altering cell growth-death regulation.