Asthma treatment resistance
Pro Research Analysisby 
Searched over 200M research papers
Mechanisms of Asthma Treatment Resistance: Steroid and Therapy Resistance
Asthma treatment resistance, particularly to corticosteroids, is a significant challenge in managing severe asthma. Many patients with severe asthma do not respond well to standard corticosteroid therapies, leading to more frequent exacerbations, hospitalizations, and a poorer quality of life 1267+1 MORE. This resistance is often referred to as corticosteroid resistance or therapy-resistant asthma.
Cellular and Molecular Mechanisms of Steroid Resistance
Several factors contribute to steroid resistance in asthma. Pro-inflammatory cytokines such as IFN-γ, TNF-α, TGF-β, IL-17A, IL-27, IL-33, and thymic stromal lymphopoietin (TSLP) play a role in reducing steroid sensitivity 110. These cytokines, along with allergens, pathogens, and cigarette smoke, can alter signaling pathways like PI3Kδ/Akt/mTOR, JAK-STAT, p38MAPK/JNK, and Nrf2/HDAC2/c-Jun, leading to steroid insensitivity 167. Changes in the glucocorticoid receptor (GR) expression and function, especially an increased GRβ/GRα ratio, are also implicated .
MicroRNAs, such as miR-9, miR-21, and miR-126, have recently been identified as contributors to corticosteroid insensitivity 16. Additionally, specific respiratory infections and environmental factors like obesity and pollution are associated with severe, steroid-resistant asthma 26.
Asthma Phenotypes and Endotypes in Treatment Resistance
Asthma is a heterogeneous disease with multiple phenotypes and endotypes, each showing different responses to corticosteroids 2579. Eosinophilic and neutrophilic inflammation are two key types. While most eosinophilic asthma responds to steroids, some severe cases remain resistant, partly due to persistent eosinophils and activation of type 2 innate lymphoid cells (ILC2) that are not suppressed by steroids . Neutrophilic asthma, often driven by IL-17, IL-8, and TNF-α, is particularly associated with steroid resistance and involves processes like NETosis, which can worsen inflammation and tissue repair .
Clinical Predictors and Assessment of Therapy-Resistant Asthma
Patients with therapy-resistant asthma often have a longer duration of symptoms, a family history of asthma, and more severe airflow obstruction 34. High doses of inhaled steroids, frequent use of rescue steroids, and lower lung function (FEV1%) are predictors of true therapy-resistant asthma . Co-morbidities such as gastroesophageal reflux, upper airway disease, and psychiatric conditions are common but do not necessarily distinguish therapy-resistant cases from those who respond to intervention .
Current and Emerging Therapeutic Strategies
For patients with severe, therapy-resistant asthma, especially those with steroid resistance, new treatment approaches are being developed. These include:
- Biologics targeting specific cytokines (e.g., anti-IL-5, anti-IL-4R, anti-TSLP) for type 2 inflammation 1589.
- Small molecule inhibitors targeting signaling pathways involved in steroid resistance 16.
- MicroRNA-specific therapies to reverse corticosteroid insensitivity 16.
- Macrolide antibiotics and other novel agents targeting non-eosinophilic, neutrophilic asthma 610.
Personalized medicine, based on detailed phenotyping and endotyping, is increasingly important for selecting the most effective therapy for each patient 589.
Conclusion
Asthma treatment resistance, particularly to corticosteroids, is driven by complex cellular, molecular, and immunological mechanisms. Understanding these mechanisms has led to the development of targeted therapies, especially biologics and small molecule inhibitors, which offer hope for patients with severe, therapy-resistant asthma. Accurate diagnosis, phenotyping, and personalized treatment strategies are essential for improving outcomes in this challenging group of patients 1256+4 MORE.
Sources and full results
Most relevant research papers on this topic