The epithelial era of asthma research: knowledge gaps and future direction for patient care.

The Epithelial Science Expert Group convened on 18-19 October 2023, in Naples, Italy, to discuss the current understanding of the fundamental role of the airway epithelium in asthma and other respiratory diseases and to explore the future direction of patient care. This review summarises the key concepts and research questions that were raised. As an introduction to the epithelial era of research, the evolution of asthma management throughout the ages was discussed and the role of the epithelium as an immune-functioning organ was elucidated.

Bronchial Rheoplasty for Chronic Bronchitis: Results from a Canadian Feasibility Study with RheOx.

Purpose: Chronic bronchitis (CB), a chronic obstructive pulmonary disease (COPD) phenotype defined by persistent mucus hypersecretion and cough, is associated with poor quality of life, exacerbations, and lung function impairment. Bronchial Rheoplasty (BR) delivers non-thermal pulsed electric fields to airway epithelium and submucosa. Preliminary studies demonstrated reduced airway goblet cell hyperplasia and symptom improvement in response to BR.

Exploring Definitions and Predictors of Response to Biologics for Severe Asthma.

Background: Biologic effectiveness is often assessed as response, a term that eludes consistent definition. Identifying those most likely to respond in real-life has proven challenging.

Objective: To explore definitions of biologic responders in adults with severe asthma and investigate patient characteristics associated with biologic response.

The airway epithelium: an orchestrator of inflammation, a key structural barrier and a therapeutic target in severe asthma.

Asthma is a disease of heterogeneous pathology, typically characterised by excessive inflammatory and bronchoconstrictor responses to the environment. The clinical expression of the disease is a consequence of the interaction between environmental factors and host factors over time, including genetic susceptibility, immune dysregulation and airway remodelling. As a critical interface between the host and the environment, the airway epithelium plays an important role in maintaining homeostasis in the face of environmental challenges.

Airway Epithelial-Derived Immune Mediators in COVID-19.

The airway epithelium, which lines the conducting airways, is central to the defense of the lungs against inhaled particulate matter and pathogens such as SARS-CoV-2, the virus that causes COVID-19. Recognition of pathogens results in the activation of an innate and intermediate immune response which involves the release of cytokines and chemokines by the airway epithelium. This response can inhibit further viral invasion and influence adaptive immunity.

Canadian multidisciplinary expert consensus on the use of biologics in upper airways: a Delphi study.

Background: Chronic rhinosinusitis with nasal polyposis (CRSwNP) often coexists with lower airway disease. With the overlap between upper and lower airway disease, optimal management of the upper airways is undertaken in conjunction with that of the lower airways. Biologic therapy with targeted activity within the Type 2 inflammatory pathway can improve the clinical signs and symptoms of both upper and lower airway diseases.

Comparative effectiveness of anti-IL5 and anti-IgE biologic classes in patients with severe asthma eligible for both.

Background: Patients with severe asthma may present with characteristics representing overlapping phenotypes, making them eligible for more than one class of biologic. Our aim was to describe the profile of adult patients with severe asthma eligible for both anti-IgE and anti-IL5/5R and to compare the effectiveness of both classes of treatment in real life.

Methods: This was a prospective cohort study that included adult patients with severe asthma from 22 countries enrolled into the International Severe Asthma registry (ISAR) who were eligible for both anti-IgE and anti-IL5/5R.

Recommendations from a Canadian Delphi consensus study on best practice for optimal referral and appropriate management of severe asthma.

Background: In Canada, severe asthma affects an estimated 5-10% of people with asthma and is associated with frequent exacerbations, poor symptom control and significant morbidity from the disease itself, as well as the high dose inhaled, and systemic steroids used to treat it. Significant heterogeneity exists in service structure and patient access to severe asthma care, including access to biologic treatments. There appears to be over-reliance on short-acting beta agonists and frequent oral corticosteroid use, two indicators of uncontrolled asthma which can indicate undiagnosed or suboptimally treated severe asthma.

Hedgehog Signaling as a Therapeutic Target for Airway Remodeling and Inflammation in Allergic Asthma.

Genome-wide association studies (GWAS) have shown that variants of patched homolog 1 () are associated with lung function abnormalities in the general population. It has also been shown that sonic hedgehog (SHH), an important ligand for PTCH1, is upregulated in the airway epithelium of patients with asthma and is suggested to be involved in airway remodeling. The contribution of hedgehog signaling to airway remodeling and inflammation in asthma is poorly described.

Lipid nanoparticle formulations for optimal RNA-based topical delivery to murine airways.

Introduction: Lipid nanoparticles (LNP) have been successfully used as a platform technology for delivering nucleic acids to the liver. To broaden the application of LNPs in targeting non-hepatic tissues, we developed LNP-based RNA therapies (siRNA or mRNA) for the respiratory tract. Such optimized LNP systems could offer an early treatment strategy for viral respiratory tract infections such as COVID-19.

FAM13A as potential therapeutic target in modulating TGF-β-induced airway tissue remodeling in COPD.

Genome-wide association studies have shown that a gene variant in the Family with sequence similarity 13, member A (FAM13A) is strongly associated with reduced lung function and the appearance of respiratory symptoms in patients with chronic obstructive pulmonary disease (COPD). A key player in smoking-induced tissue injury and airway remodeling is the transforming growth factor-β1 (TGF-β1). To determine the role of FAM13A in TGF-β1 signaling, airway epithelial cells were generated using CRISPR-Cas9, whereas overexpression of FAM13A was achieved using lipid nanoparticles.

IL-4Rα blockade reduces influenza-associated morbidity in a murine model of allergic asthma.

Background: Asthma was identified as the most common comorbidity in hospitalized patients during the 2009 H1N1 influenza pandemic. We determined using a murine model of allergic asthma whether these mice experienced increased morbidity from pandemic H1N1 (pH1N1) viral infection and whether blockade of interleukin-4 receptor α (IL-4Rα), a critical mediator of T2 signalling, improved their outcomes.

Methods: Male BALB/c mice were intranasally sensitized with house dust mite antigen (Der p 1) for 2 weeks; the mice were then inoculated intranasally with a single dose of pandemic H1N1 (pH1N1).

Olodaterol exerts anti-inflammatory effects on COPD airway epithelial cells.

Background: Airway inflammation is a key feature of chronic obstructive pulmonary disease (COPD) and inhaled corticosteroids (ICS) remain the main treatment for airway inflammation. Studies have noted the increased efficacy of ICS and long-acting beta 2 agonist (LABA) combination therapy in controlling exacerbations and improving airway inflammation than either monotherapy. Further studies have suggested that LABAs may have inherent anti-inflammatory potential, but this has not been well-studied.

Various factors affect lipopolysaccharide sensitization in cell cultures.

Commercially available lipopolysaccharide (LPS) is commonly used in research. Although protocols for its use are well established, we experienced a loss of LPS responsiveness in our cell cultures despite no obvious experimental changes. Our cell lines were stimulated with LPS and the media quantified for LPS responsiveness via an IL-8 ELISA.

ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19.

https://bit.ly/3bC29es

Structural and functional variations in human bronchial epithelial cells cultured in air-liquid interface using different growth media.

The human bronchial epithelium is an important barrier tissue that is damaged or pathologically altered in various acute and chronic respiratory conditions. To represent the epithelial component of respiratory disease, it is essential to use a physiologically relevant model of this tissue. The human bronchial epithelium is a highly organized tissue consisting of a number of specialized cell types.

Omalizumab in patients with severe asthma and persistent sputum eosinophilia.

Omalizumab, a recombinant humanized monoclonal antibody targeting the IgE molecule, is the first biologic approved for moderate-to-severe allergic asthmatics, who remain uncontrolled despite high dose inhaled corticosteroid and bronchodilators. Steroid-sparing effect of omalizumab has not been demonstrated in asthmatics with persistent airway eosinophilia in a randomised controlled trial till date. From this double-blind, placebo-controlled, multi-centred, randomized parallel group design, we report that omalizumab is possibly inadequate to control sputum eosinophilia, and therefore may not have a steroid-sparing effect, especially in those maintained on oral corticosteroids daily.

Hedgehog signaling in the airway epithelium of patients with chronic obstructive pulmonary disease.

Genome-wide association studies have linked gene variants of the receptor patched homolog 1 (PTCH1) with chronic obstructive pulmonary disease (COPD). However, its biological role in the disease is unclear. Our objective was to determine the expression pattern and biological role of PTCH1 in the lungs of patients with COPD.

IL-13 signaling through IL-13 receptor α2 mediates airway epithelial wound repair.

Asthma is an airway inflammatory disease characterized by epithelial barrier dysfunction and airway remodeling. Interleukin-13 (IL-13) is a pleiotropic cytokine shown to contribute to features of airway remodeling. We have previously demonstrated that IL-13 is an important mediator of normal airway epithelial repair and health.