The mechanisms, diagnosis, and management of severe asthma in adults

Bronchial Asthma and COVID-19: Etiology, Pathological Triggers, and Therapeutic Considerations

Bronchial asthma (BA) continues to be a difficult disease to diagnose. Various factors have been described in the development of BA, but to date, there is no clear evidence for the etiology of this chronic disease. The emergence of COVID-19 has contributed to the pandemic course of asthma and immunologic features. However, there are no unambiguous data on asthma on the background and after COVID-19. There is correlation between various trigger factors that provoke the development of bronchial asthma. It is now obvious that the SARS-CoV-2 virus is one of the provoking factors. COVID-19 has affected the course of asthma. Currently, there is no clear understanding of whether asthma progresses during or after COVID-19 infection. According to the results of some studies, a significant difference was identified between the development of asthma in people after COVID-19. Mild asthma and moderate asthma do not increase the severity of COVID-19 infection. Nevertheless, oral steroid treatment and hospitalization for severe BA were associated with higher COVID-19 severity. The influence of SARS-CoV-2 infection is one of the protective factors. It causes the development of severe bronchial asthma. The accumulated experience with omalizumab in patients with severe asthma during COVID-19, who received omalizumab during the pandemic, has strongly suggested that continued treatment with omalizumab is safe and may help prevent the severe course of COVID-19. Targeted therapy for asthma with the use of omalizumab may also help to reduce severe asthma associated with COVID-19. However, further studies are needed to prove the effect of omalizumab. Data analysis should persist, based on the results of the course of asthma after COVID-19 with varying degrees of severity.

Aspirin hypersensitivity: a practical guide for cardiologists

Aspirin has been known for a long time and currently stays as a cornerstone of antithrombotic therapy in cardiovascular disease. In patients with either acute or chronic coronary syndromes undergoing percutaneous coronary intervention aspirin is mandatory in a dual antiplatelet therapy regimen for prevention of stent thrombosis and/or new ischaemic events. Aspirin is also currently a first-option antithrombotic therapy after an aortic prosthetic valve replacement and is occasionally required in addition to oral anticoagulants after implantation of a mechanical valve. Presumed or demonstrated aspirin hypersensitivity is a main clinical problem, limiting the use of a life-saving medication. In the general population, aspirin hypersensitivity has a prevalence of 0.6%-2.5% and has a plethora of clinical presentations, ranging from aspirin-exacerbated respiratory disease to anaphylaxis. Although infrequent, when encountered in clinical practice aspirin hypersensitivity poses for cardiologists a clinical dilemma, which should never be trivialized, avoiding-as much as possible-omission of the drug. We here review the epidemiology of aspirin hypersensitivity, provide an outline of pathophysiological mechanisms and clinical presentations, and review management options, starting from a characterization of true aspirin allergy-in contrast to intolerance-to suggestion of desensitization protocols.

Breath of fresh air: Investigating the link between AGEs, sRAGE, and lung diseases

Advanced glycation end products (AGEs) are compounds formed via non-enzymatic reactions between reducing sugars and amino acids or proteins. AGEs can accumulate in various tissues and organs and have been implicated in the development and progression of various diseases, including lung diseases. The receptor of advanced glycation end products (RAGE) is a receptor that can bind to advanced AGEs and induce several cellular processes such as inflammation and oxidative stress. Several studies have shown that both AGEs and RAGE play a role in the pathogenesis of lung diseases, such as chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis, cystic fibrosis, and acute lung injury. Moreover, the soluble form of the receptor for advanced glycation end products (sRAGE) has demonstrated its ability to function as a decoy receptor, possessing beneficial characteristics such as anti-inflammatory, antioxidant, and anti-fibrotic properties. These qualities make it an encouraging focus for therapeutic intervention in managing pulmonary disorders. This review highlights the current understanding of the roles of AGEs and (s)RAGE in pulmonary diseases and their potential as biomarkers and therapeutic targets for preventing and treating these pathologies.

The role of hormones in ILC2-driven allergic airway inflammation

Group 2 innate lymphoid cells (ILC2s) are a type of innate immune cells that produce a large amount of IL-5 and IL-13 and two cytokines that are crucial for various processes such as allergic airway inflammation, tissue repair and tissue homeostasis. It is known that damaged epithelial-derived alarmins, such as IL-33, IL-25 and thymic stromal lymphopoietin (TSLP), are the predominant ILC2 activators that mediate the production of type 2 cytokines. In recent years, abundant studies have found that many factors can regulate ILC2 development and function. Hormones synthesized by the body's endocrine glands or cells play an important role in immune response. Notably, ILC2s express hormone receptors and their proliferation and function can be modulated by multiple hormones during allergic airway inflammation. Here, we summarize the effects of multiple hormones on ILC2-driven allergic airway inflammation and discuss the underlying mechanisms and potential therapeutic significance.

Steroid-Insensitive Gene Expression of Extracellular Matrix Components and Pro-fibrotic Factors in the Lung Associated with Airway Hyperresponsiveness in Murine Asthma

Between 5 and 10% of asthma patients do not respond to glucocorticoid therapy. Experimental animal models are indispensable for investigating the pathogenesis of steroid-resistant asthma; however, the majority of murine asthma models respond well to glucocorticoids. We previously reported that multiple intratracheal administration of ovalbumin (OVA) at a high dose (500 µg/animal) induced steroid-insensitive airway eosinophilia and remodeling with lung fibrosis, whereas a low dose (5 µg/animal) caused steroid-sensitive responses. The aims of the present study were as follows: 1) to clarify whether airway hyperresponsiveness (AHR) in the two models is also insensitive and sensitive to a glucocorticoid, respectively, and 2) to identify steroid-insensitive genes encoding extracellular matrix (ECM) components and pro-fibrotic factors in the lung. In comparisons with non-challenged group, the 5- and 500-µg OVA groups both exhibited AHR to methacholine. Daily intraperitoneal treatment with dexamethasone (1 mg/kg) significantly suppressed the development of AHR in the 5-µg OVA group, but not in the 500-µg OVA group. Among genes encoding ECM components and pro-fibrotic factors, increased gene expressions of fibronectin and collagen types I, III, and IV as ECM components as well as 7 matrix metalloproteinases, tissue inhibitor of metalloproteinase-1, transforming growth factor-β1, and activin A/B as pro-fibrotic factors were insensitive to dexamethasone in the 500-µg OVA group, but were sensitive in the 5-µg OVA group. In conclusion, steroid-insensitive AHR developed in the 500-µg OVA group and steroid-insensitive genes encoding ECM components and pro-fibrotic factors were identified. Drugs targeting these molecules have potential in the treatment of steroid-resistant asthma.

Approach for Elucidating the Molecular Mechanism of Epithelial to Mesenchymal Transition in Fibrosis of Asthmatic Airway Remodeling Focusing on Cl- Channels

Airway remodeling caused by asthma is characterized by structural changes of subepithelial fibrosis, goblet cell metaplasia, submucosal gland hyperplasia, smooth muscle cell hyperplasia, and angiogenesis, leading to symptoms such as dyspnea, which cause marked quality of life deterioration. In particular, fibrosis exacerbated by asthma progression is reportedly mediated by epithelial-mesenchymal transition (EMT). It is well known that the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling is closely associated with several signaling pathways, including the TGF-β1/Smad, TGF-β1/non-Smad, and Wnt/β-catenin signaling pathways. However, the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling has not yet been fully clarified. Given that Cl- transport through Cl- channels causes passive water flow and consequent changes in cell volume, these channels may be considered to play a key role in EMT, which is characterized by significant morphological changes. In the present article, we highlight how EMT, which causes fibrosis and carcinogenesis in various tissues, is strongly associated with activation or inactivation of Cl- channels and discuss whether Cl- channels can lead to elucidation of the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling.

The treatable traits approach to adults with obstructive airways disease in primary and secondary care

The treatable traits approach is based on the recognition that the different clinical phenotypes of asthma and chronic obstructive airways disease (COPD) are a heterogeneous group of conditions with different underlying mechanisms and clinical manifestations, and that the identification and treatment of the specific clinical features or traits facilitates a personalised approach to management. Fundamentally, it recognises two important concepts. Firstly, that treatment for obstructive lung disease can achieve better outcomes if guided by specific clinical characteristics. Secondly, that in patients with a diagnosis of asthma, and/or COPD, poor respiratory health may also be due to numerous overlapping disorders that can present with symptoms that may be indistinguishable from asthma and/or COPD, comorbidities that might require treatment in their own right, and lifestyle or environmental factors that, if addressed, might lead to better control rather than simply increasing airways directed treatment. While these concepts are well accepted, how best to implement this personalised medicine approach in primary and secondary care within existing resource constraints remains uncertain. In this review, we consider the evidence base for this management approach and propose that the priority now is to assess different prototype templates for the identification and management of treatable traits in both asthma and COPD, in primary, secondary and tertiary care, to provide the evidence that will guide their use in clinical practice in different health care systems.

Diverse Endotypes of Chronic Rhinosinusitis and Clinical Implications

Chronic rhinosinusitis (CRS) is a highly heterogeneous disease characterized by inflammation in the nasal and sinus mucosa. The CRS phenotypes, based on the presence or absence of nasal polyps, are known as CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). However, this classification has limitations in fully capturing the mechanisms and clinical manifestations of CRS. To address the heterogeneity of CRS, there has been a growing focus on classifying the condition into distinct endotypes. Endotype classification involves grouping patients based on specific molecular, immunological, and clinical characteristics, allowing for more personalized and targeted treatment approaches.This review delves into the current state of endotype classifications for CRS. It explores the role of geographic factors, microbiome, and subphenotype in shaping different endotypes. Additionally, the review examines how various clinical features are associated with specific endotypes, providing valuable insights into tailoring treatment options for better outcomes and transitions between different endotypes.Overall, this review offers a comprehensive and up-to-date perspective on the intricate realm of CRS endotype classifications. By unraveling the molecular and clinical intricacies, this review lays the foundation for more precise, effective, and individualized treatment strategies in the management of CRS.

Local glucocorticoid synthesis regulates house dust mite-induced airway hypersensitivity in mice

Background

Extra-adrenal glucocorticoid (GC) synthesis at epithelial barriers, such as skin and intestine, has been shown to be important in the local regulation of inflammation. However, the role of local GC synthesis in the lung is less well studied. Based on previous studies and the uncontentious efficacy of corticosteroid therapy in asthma patients, we here investigated the role of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1/Hsd11b1)-dependent local GC reactivation in the regulation of allergic airway inflammation.

Methods

Airway inflammation in Hsd11b1-deficient and C57BL/6 wild type mice was analyzed after injection of lipopolysaccharide (LPS) and anti-CD3 antibody, and in acute and chronic models of airway hypersensitivity induced by house dust mite (HDM) extract. The role of 11β-HSD1 in normal and inflammatory conditions was assessed by high dimensional flow cytometry, histological staining, RT-qPCR analysis, ex vivo tissue cultures, GC-bioassays and protein detection by ELISA and immunoblotting.

Results

Here we show that lung tissue from Hsd11b1-deficient mice synthesized significantly less GC ex vivo compared with wild type animals in response to immune cell stimulation. We further observed a drastically aggravated phenotype in Hsd11b1-deficient mice treated with HDM extract compared to wild type animals. Besides eosinophilic infiltration, Hsd11b1-deficient mice exhibited aggravated neutrophilic infiltration caused by a strong Th17-type immune response.

Conclusion

We propose an important role of 11β-HSD1 and local GC in regulating Th17-type rather than Th2-type immune responses in HDM-induced airway hypersensitivity in mice by potentially controlling Toll-like receptor 4 (TLR4) signaling and cytokine/chemokine secretion by airway epithelial cells.

miR-146a-3p as a potential novel therapeutic by targeting MBD2 to mediate Th17 differentiation in Th17 predominant neutrophilic severe asthma

Th17 (T-helper 17) cells subtype of non-T2 (non-type 2) asthma is related to neutrophilic infiltration and resistance to inhaled corticosteroids (ICS), so is also known as severe asthma. Methyl-CpG binding domain protein 2 (MBD2) regulates the differentiation of the Th17 cells, tending to show a therapeutic target in severe asthma. miR-146a-3p is associated with anti-inflammatory characteristics and immunity. Moreover, bioinformatic analysis showed that MBD2 may be a target gene of miR-146a-3p. However, the role of miR-146a-3p in the differentiation of Th17 cells via MBD2 in severe asthma remains unknown. Here, we aimed to explore how miR-146a-3p interacts with MBD2 and affects the differentiation of Th17 cells in severe asthma. First, we recruited 30 eligible healthy people and 30 patients with severe asthma to detect the expression of miR-146a-3p in peripheral blood mononuclear cells (PBMCs) by qRT-PCR. Then, we established a HDM/LPS (house dust mite/lipopolysaccharide) exposure model of bronchial epithelial cells (BECs) to evaluate the expression of miR-146a-3p, the interaction between miR-146a-3p and MBD2 using western blot and luciferase reporter analysis and the effect of miR-146a-3p regulated Th17 cells differentiation by flow cytometry in BECs in vitro. Finally, we constructed a mouse model of Th17 predominant neutrophilic severe asthma to assess the therapeutic potential of miR-146a-3p in severe asthma and the effect of miR-146a-3p regulated Th17 cells differentiation via MBD2 in vivo. Decreased miR-146a-3p expression was noted in severe asthma patients, in the BECs and in the animal severe asthma models. Moreover, we demonstrated that miR-146a-3p suppressed Th17 cells differentiation by targeting the MBD2. miR-146a-3p overexpression significantly reduced airway hyperresponsiveness, airway inflammation and airway mucus secretion, while also inhibiting Th17 cells response in vivo, which relieved severe asthma. By targeting MBD2 to suppress Th17 cells differentiation, miR-146a-3p provides a potential novel therapeutic for Th17 predominant neutrophilic severe asthma.

Inadequate therapeutic responses to glucocorticoid treatment in bronchial asthma

Bronchial asthma (BA) is a heterogeneous disease. Some patients benefit greatly from glucocorticoid (GC) treatment, whereas others are non-responders. This could be attributable to differences in pathobiology. Thus, predicting the responses to GC treatment in patients with BA is necessary to increase the success rates of GC therapy and avoid adverse effects. The sustained inflammation in BA decreases glucocorticoid receptor (GR, NR3C1) function. Meanwhile, GRβ overexpression might contribute to GC resistance. Important factors in decreased GR function include p38 mitogen-activated protein kinase-dependent GR phosphorylated at Ser226, reduced expression of histone deacetylase 2 following activation of the phosphatidylinositol 3-kinase-δ signaling pathway, and increased nuclear factor-kappa B activity. MicroRNAs, which are involved in GC sensitivity, are considered biomarkers of the response to inhaled GCs. Some studies revealed that inflammatory phenotypes and disease-related modifiable factors, including infections, the airway microbiome, mental stress, smoking, and obesity, regulate individual sensitivity to GCs. Therefore, future investigations are warranted to improve treatment outcomes.

The Role and Clinical Relevance of Osteopontin in Allergic Airway Diseases

The airway epithelium is exposed to numerous external irritants including infectious agents, environmental allergens, and atmospheric pollutants, releasing epithelial cytokines including thymic stromal lymphopoietin (TSLP), IL-33, and IL-25 and initiating downstream type 2 (IL-4, IL-13, and IL-5) and IgE-driven pathways. These pathways trigger the initiation and progression of allergic airway diseases, including chronic rhinosinusitis with nasal polyps (CRSwNP), allergic rhinitis (AR), and allergic asthma. However, the use of biological agents that target downstream cytokines, such as IL-5, IL-4, and IL-13 receptors and IgE, might not be sufficient to manage some patients successfully. Instead of blocking downstream cytokines, targeting upstream epithelial cytokines has been proposed to address the complex immunologic networks associated with allergic airway diseases. Osteopontin (OPN), an extracellular matrix glyco-phosphoprotein, is a key mediator involved in Th1-related diseases, including systemic lupus erythematosus, multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis. Emerging evidence, including ours, indicates that epithelial-cell-derived OPN also plays an essential role in Th2-skewed airway diseases, including CRSwNP, AR, and allergic asthma involving the Th17 response. Therefore, we reviewed the current knowledge of epithelial-cell-derived OPN in the pathogenesis of three type-2-biased airway diseases and provided a direction for its future investigation and clinical relevance.

Airway Epithelium: A Neglected but Crucial Cell Type in Asthma Pathobiology

The features of allergic asthma are believed to be mediated mostly through the Th2 immune response. In this Th2-dominant concept, the airway epithelium is presented as the helpless victim of Th2 cytokines. However, this Th2-dominant concept is inadequate to fill some of the vital knowledge gaps in asthma pathogenesis, like the poor correlation between airway inflammation and airway remodeling and severe asthma endotypes, including Th2-low asthma, therapy resistance, etc. Since the discovery of type 2 innate lymphoid cells in 2010, asthma researchers started believing in that the airway epithelium played a crucial role, as alarmins, which are the inducers of ILC2, are almost exclusively secreted by the airway epithelium. This underscores the eminence of airway epithelium in asthma pathogenesis. However, the airway epithelium has a bipartite functionality in sustaining healthy lung homeostasis and asthmatic lungs. On the one hand, the airway epithelium maintains lung homeostasis against environmental irritants/pollutants with the aid of its various armamentaria, including its chemosensory apparatus and detoxification system. Alternatively, it induces an ILC2-mediated type 2 immune response through alarmins to amplify the inflammatory response. However, the available evidence indicates that restoring epithelial health may attenuate asthmatic features. Thus, we conjecture that an epithelium-driven concept in asthma pathogenesis could fill most of the gaps in current asthma knowledge, and the incorporation of epithelial-protective agents to enhance the robustness of the epithelial barrier and the combative capacity of the airway epithelium against exogenous irritants/allergens may mitigate asthma incidence and severity, resulting in better asthma control.

Brain-Airway Interactions in Asthma

Asthma and brain interactions have long been appreciated and initially centered on increased anxiety and depression. Epidemiology studies have shown that early life stressors and situational disadvantages are risk factors for asthma. Conversely, the presence of asthma is a risk for mood and anxiety disorders, thus indicating a bidirectional effect between asthma and brain-related health. To substantiate asthma-brain interactions, validated instruments indicate and elucidate that communication likely exists between asthma and the brain. For example, provocation of an asthmatic response with an allergen challenge modulates how the brain responds to emotion-laden information. As detected by imaging studies, emotion-related brain activation is associated with generating airway inflammation. However, the specific mediators and processes mediating airway communication with the brain have yet to be established.Systemic inflammation is also associated with asthma and can affect other organ systems such as the cardiovascular system and the brain. Epidemiology studies have shown that asthma is a risk factor for dementia and Alzheimer's disease. In support of the importance of asthma as a risk factor for impaired cognitive function, imaging studies have shown changes to the white matter of the brain in asthma patients that resemble neuroinflammation changes seen in Alzheimer's disease and other neurodegenerative diseases. Therefore, bidirectional links between asthma and the brain exist with an important next research step to define asthma-brain interactions linked to neurodegeneration and dementia and explore whether treatments directed toward asthma-related inflammation can prevent the deleterious effects of asthma on brain health.

A bibliometric and scientific knowledge map study of the drug therapies for asthma-related study from 1982 to 2021

Objective: Asthma drug research has been increasing yearly, and its clinical application value has increasingly attracted attention. This study aimed to analyze the development status, research hotspots, research frontiers, and future development trends of the research works on drugs for patients with asthma, especially severe asthma.

Methods: Asthma drug-related articles published between 1982 and 2021 were retrieved from the Web of Science Core Collection (WOSCC) database, and only articles published in English were included. CiteSpace and VOSviewer software were utilized to conduct collaborative network analysis of countries/regions, institutions, keywords, and co-citation analysis of references.

Results: A total of 3,234 asthma drug-related eligible articles were included. The United States was in a leading position, and Karolinska Institute (Sweden) was the most active institution. The most prolific journal in this field was Journal of Asthma, and the most cited journal was Journal of Allergy and Clinical Immunology. Keyword co-occurrence studies suggested that the current hotspots and frontiers were as follows: ① asthma: fully revealing the potential of existing conventional asthma drugs, determining the best drug delivery system, and indicating the best combination. To continue to explore potential targets for severe asthma or other phenotypes. Inhaled glucocorticoids and budesonide are still one of the important aspects of current asthma drug research and ② severe asthma: the research and development of new drugs, especially monoclonal antibodies including omalizumab, mepolizumab, and benralizumab to improve asthma control and drug safety, have become a research hotspot in recent years, highlighting the importance of “target” selection.

Conclusion: This study demonstrates the global research hotspots and trends of the research works on drugs for patients with asthma/severe asthma. It can help scholars quickly understand the current status and hotspots of research in this field.

Type 2 inflammation in asthma and other airway diseases

Chronic inflammatory airway diseases, including asthma, chronic rhinosinusitis, eosinophilic COPD and allergic rhinitis are a global health concern. Despite the coexistence of these diseases and their common pathophysiology, they are often managed independently, resulting in poor asthma control, continued symptoms and poor quality of life. Understanding disease pathophysiology is important for best treatment practice, reduced disease burden and improved patient outcomes. The pathophysiology of type 2 inflammation is driven by both the innate immune system triggered by pollutants, viral or fungal infections involving type 2 innate lymphoid cells (ILC2) and the adaptive immune system, triggered by contact with an allergen involving type 2 T-helper (Th2) cells. Both ILC2 and Th2 cells produce the type-2 cytokines (interleukin (IL)-4, IL-5 and IL-13), each with several roles in the inflammation cascade. IL-4 and IL-13 cause B-cell class switching and IgE production, release of pro-inflammatory mediators, barrier disruption and tissue remodelling. In addition, IL-13 causes goblet-cell hyperplasia and mucus production. All three interleukins are involved in trafficking eosinophils to tissues, producing clinical symptoms characteristic of chronic inflammatory airway diseases. Asthma is a heterogenous disease; therefore, identification of biomarkers and early targeted treatment is critical for patients inadequately managed by inhaled corticosteroids and long-acting β-agonists alone. The Global Initiative for Asthma guidelines recommend add-on biological (anti IgE, IL-5/5R, IL-4R) treatments for those not responding to standard of care. Targeted therapies, including omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab and tezepelumab, were developed on current understanding of the pathophysiology of type 2 inflammation. These therapies offer hope for improved management of type 2 inflammatory airway diseases.

Plasma Metabolites and Gut Microbiota Are Associated With T cell Imbalance in BALB/c Model of Eosinophilic Asthma

The pathogenesis of allergic asthma is complex, it is usually caused by immune system imbalance. Th1, Th2, regulatory T cells (Treg) and T helper 17 (Th17) cells have an important role in the pathogenesis of eosinophilic asthma. Yet, the exact role of Th1, Th2, Treg and Th17 cells in eosinophilic asthmatic disease is not fully understood. This study used an untargeted plasma metabolomics combine 16S rDNA technology to identify new biomarkers of plasma metabolites and gut microbiota in ovalbumin-induced eosinophilic allergic asthma in BALB/c mice to further explore the biomarkers in regulating the immune balance or the immune response. We discovered that malate, l-dihydroorotate were associated with Th1/Th2 and Treg/Th17 cells balance, imidazoleacetic acid was associated with Th1/Th2 cell balance, 1,5-anhydro-d-sorbitol was associated with Treg/Th17 cell balance. The results also found that genus Candidatus Arthromitus of gut microbiota were associated with Th1/2, Treg/Th17 balance, genus Ruminiclostridium 6, they were all associated with Th1/2 and Treg/Th17 cell balance, while the gut microbiota were not associated with penh value which reflect airway hyperresponsiveness (AHR) in the eosinophilic asthma mice model. Interestingly, the plasma metabolite biomarkers of malate, l-dihydroorotate are associated with genus Ruminiclostridium 6, they were all associated with Th1/2 and Treg/Th17 cell balance, while imidazoleacetic acid is associated with genus Ruminiclostridium 6 which is associated with Th1/2 balance. Among the differential plasma metabolites, 1,5-anhydro-d-sorbitol is associated with genus Ruminiclostridium 6 and genus Candidatus Arthromitus. Among them, malate participate in the T cell activation, T cell differentiation and activation may be a new research direction in eosinophilic allergic asthma. We firstly study the gut microbiota and plasma metabolites markers of immune balance in eosinophilic asthma in mice model, laying a foundation for drug treatment in eosinophilic allergic asthma.

Cellular mechanism underlying the facilitation of contractile response induced by IL-25 in mouse tracheal smooth muscle

Asthma is a common heterogeneous respiratory disease characterized by airway inflammation and airway hyperresponsiveness (AHR) which is associated with abnormality in smooth muscle contractility. The epithelial cell-derived cytokine IL-25 is implicated in type 2 immune pathology including asthma, whereas the underlying mechanisms have not been fully elucidated. This study aims to investigate the effects of IL-25 on mouse tracheal smooth muscle contractility and elucidate the cellular mechanisms. Incubation with IL-25 augmented the contraction of mouse tracheal smooth muscles, which could be suppressed by the L-type voltage-dependent Ca²⁺ channel (L-VDCC) blocker nifedipine. Furthermore, IL-25 enhanced the cytosolic Ca²⁺ signals and triggered up-regulation of α1C L-VDCC (Ca_V1.2) in primary cultured mouse tracheal smooth muscle cells. Knocking down IL-17RA/IL-17RB receptors or inhibiting the transforming growth factor-β-activated kinase 1 (TAK1)-tumor progression locus 2 (TPL2)-MAPK kinase 1/2 (MEK1/2)-ERK1/2-activating protein-1 (AP-1) signaling pathways suppressed the IL-25-elicited up-regulation of Ca_V1.2 and hyperreactivity in tracheal smooth muscles. Moreover, inhibition of TPL2, ERK1/2 or L-VDCC alleviated the AHR symptom induced by IL-25 in a murine model. This study revealed that IL-25 potentiated the contraction of tracheal smooth muscle and evoked AHR via activation of TPL2-ERK1/2-Ca_V1.2 signaling, providing novel targets for the treatment of asthma with a high-IL-25 phenotype.

A SPLUNC1 Peptidomimetic Inhibits Orai1 and Reduces Inflammation in a Murine Allergic Asthma Model

Orai1 is a plasma membrane Ca2+ channel that mediates store-operated Ca2+ entry (SOCE) and regulates inflammation. Short palate lung and nasal epithelial clone 1 (SPLUNC1) is an asthma gene modifier that inhibits Orai1 and SOCE via its C-terminal α6 region. SPLUNC1 levels are diminished in asthma patient airways. Thus, we hypothesized that inhaled α6 peptidomimetics could inhibit Orai1 and reduce airway inflammation in a murine asthma model. To evaluate α6-Orai1 interactions, we used fluorescent assays to measure Ca2+ signaling, Förster resonance energy transfer, fluorescent recovery after photobleaching, immunostaining, total internal reflection microscopy, and Western blotting. To test whether α6 peptidomimetics inhibited SOCE and decreased inflammation in vivo, wild-type and SPLUNC1-/- mice were exposed to house dust mite (HDM) extract with or without α6 peptide. We also performed nebulization, jet milling, and scanning electron microscopy to evaluate α6 for inhalation. SPLUNC1-/- mice had an exaggerated response to HDM. In BAL-derived immune cells, Orai1 levels increased after HDM exposure in SPLUNC1-/- but not wild-type mice. Inhaled α6 reduced Orai1 levels in mice regardless of genotype. In HDM-exposed mice, α6 dose-dependently reduced eosinophilia and neutrophilia. In vitro, α6 inhibited SOCE in multiple immune cell types, and α6 could be nebulized or jet milled without loss of function. These data suggest that α6 peptidomimetics may be a novel, effective antiinflammatory therapy for patients with asthma.

Immunoglobulin E-Dependent Activation of Immune Cells in Rhinovirus-Induced Asthma Exacerbation

Acute exacerbation is the major cause of asthma morbidity, mortality, and health-care costs. Respiratory viral infections, particularly rhinovirus (RV) infections, are associated with the majority of asthma exacerbations. The risk for bronchoconstriction with RV is associated with allergic sensitization and type 2 airway inflammation. The efficacy of the humanized anti-IgE monoclonal antibody omalizumab in treating asthma and reducing the frequency and severity of RV-induced asthma exacerbation is well-known. Despite these clinical data, mechanistic details of omalizumab's effects on RV-induced asthma exacerbation have not been well-defined for years due to the lack of appropriate animal models. In this Perspective, we discuss potential IgE-dependent roles of mast cells and dendritic cells in asthma exacerbations.

Health outcomes after stopping long-term mepolizumab in severe eosinophilic asthma: COMET

Asthma worsening and symptom control are clinically important health outcomes in patients with severe eosinophilic asthma. This analysis of COMET evaluated whether stopping versus continuing long-term mepolizumab therapy impacted these outcomes.

Patients with severe eosinophilic asthma with ≥3 years continuous mepolizumab treatment (via COLUMBA (NCT01691859) or COSMEX (NCT02135692) open-label studies) were eligible to enter COMET (NCT02555371), a randomised, double-blind, placebo-controlled study. Patients were randomised 1:1 to continue mepolizumab 100 mg subcutaneous every 4 weeks or to stop mepolizumab, plus standard of care asthma treatment. Patients could switch to open-label mepolizumab following an exacerbation. Health outcome endpoints included time to first asthma worsening (composite endpoint: rescue use, symptoms, awakening at night and morning peak expiratory flow (PEF)), patient and clinician assessed global rating of asthma severity and overall perception of response to therapy, and unscheduled healthcare resource utilisation.

Patients who stopped mepolizumab showed increased risk of and shorter time to first asthma worsening compared with those who continued mepolizumab (hazard ratio (HR) 1.71; 95% CI 1.17–2.52; p=0.006), including reduced asthma control (increased risk of first worsening in rescue use (HR 1.36; 95% CI 1.00–1.84; p=0.047) and morning PEF (HR 1.77; 95% CI 1.21–2.59; p=0.003). There was a higher probability of any unscheduled healthcare resource use (HR 1.81; 95% CI 1.31–2.49; p<0.001), and patients and clinicians reported greater asthma severity and less favourable perceived response to therapy for patients who stopped versus continued mepolizumab.

These data suggest that patients with severe eosinophilic asthma continuing long-term mepolizumab treatment sustain clinically important improvements in health outcomes.

The COMET study investigated whether stopping long-term mepolizumab had an impact on health outcomes in patients with severe eosinophilic asthma; data suggest those who continue long-term mepolizumab treatment sustain clinically important improvementshttps://bit.ly/3A0bvwu

Improving the risk-to-benefit ratio of inhaled corticosteroids through delivery and dose: current progress and future directions

INTRODUCTION

Inhaled corticosteroids (ICS) are known to increase the risk of systemic and local adverse effects, especially with high doses and long-term use. Hence, considerable resources are invested to improve pharmacokinetic/pharmacodynamic (PK/PD) properties of ICS, effective delivery systems and novel combination therapies to enhance the risk-to-benefit ratio of ICS.

AREAS COVERED

There is an unmet need for new solutions to achieve optimal clinical outcomes with minimal dose of ICS. This paper gives an overview of novel treatment strategies regarding the safety of ICS therapy on the basis of the three most recent molecules introduced to our everyday clinical practice - ciclesonide, mometasone furoate, and fluticasone furoate. Advances in aerosol devices and new areas of inhalation therapy are also discussed.

EXPERT OPINION

Current progress in improving the risk-to-benefit ratio of ICS through dose and delivery probably established pathways for further developments. This applies both to the improvement of the PK/PD properties of ICS molecules but also includes technical aspects that lead to simplified applicability of the device with simultaneous optimal drug deposition in the lungs. Indubitably, the future of medicine lies not only in the development of new molecules but also in technology and digital revolution.

Paucigranulocytic asthma: Do sputum macrophages matter?

Background: Although paucigranulocytic asthma (PGA) is the most common phenotype of stable asthma, its features have not been adequately studied. In this study, we aimed to display the characteristics of PGA. Method: A total of 116 non-smoking adult patients with asthma (80% women; mean ± standard deviation age, 39 ± 12.9 years) admitted to three tertiary centers were included. Their demographic and clinical features, allergy status, biochemical results, scores of Asthma Control Test (ACT), spirometry, and exhaled nitric oxide (FeNO) measurements were obtained. Induced sputum cytometry was performed. Results: Four phenotypes, according to induced sputum cell counts, were detected: eosinophilic asthma (EA) (22.4%), mixed granulocytic asthma (MGA) (6.9%), neutrophilic (NA) (7.8%), and PGA (62.9%). In the sputum, macrophages were higher in the PGA group compared with the other groups (PGA versus NA and PGA versus MGA, p < 0.001; and PGA versus EA, p =0 .030). The atopy rate between phenotypes was the same. Although the forced expiratory volume in the first second of expiration (FEV₁) was similar in four groups, the ratio of FEV₁ to the forced vital capacity ratio was higher (p = 0.013) and FEV₁ reversibility was lower in the patients with PGA than the corresponding values in other phenotypes (p = 0.015). Low reversibility was comparable both in patients with PGA who were inhaled corticosteroid (ICS) naive and in patients on ICS treatment. Although insignificant, the FeNO values and blood eosinophil counts were higher in the MGA and EA groups, whereas these were the lowest in the PGA group. The uncontrolled asthma ratio was low in PGA (16%), whereas it was 11% for NA, 25% for MG, and 23% in EA. Conclusion: Macrophages are predominant in sputum of patients with PGA. Besides a lower uncontrolled asthma ratio, lower FEV₁ reversibility is a prominent characteristic of this phenotype.

Myeloid-Derived Suppressor Cells Dampen Airway Inflammation Through Prostaglandin E2 Receptor 4

Emerging evidence suggests a mechanistic role for myeloid-derived suppressor cells (MDSCs) in lung diseases like asthma. Previously, we showed that adoptive transfer of MDSCs dampens lung inflammation in murine models of asthma through cyclooxygenase-2 and arginase-1 pathways. Here, we further dissected this mechanism by studying the role and therapeutic relevance of the downstream mediator prostaglandin E2 receptor 4 (EP4) in a murine model of asthma. We adoptively transferred MDSCs generated using an EP4 agonist in a murine model of asthma and studied the consequences on airway inflammation. Furthermore, pegylated human arginase-1 was used to model MDSC effector activities. We demonstrate that the selective EP4 agonist L-902,688 increased the number and suppressive activity of MDSCs through arginase-1 and nitric oxide synthase-2. These results showed that adoptive transfer of EP4-primed MDSCs, EP4 agonism alone or arginase-1 administration ameliorated lung inflammatory responses and histopathological changes in asthmatic mice. Collectively, our results provide evidence that MDSCs dampen airway inflammation in murine asthma through a mechanism involving EP4.

Is there clinical value in performing capsaicin cough challenges in patients with severe asthma?

Over 330 million people have been diagnosed with asthma worldwide [1], of whom 5–10% are classified as severe [2]. Despite use of high doses of inhaled corticosteroids (ICS), long-acting bronchodilators (LABA) and/or maintenance oral steroid use, patients with severe asthma account for over 50% of the asthma healthcare budget [3, 4]. Largely due to exacerbations requiring hospitalisation, and cost of treatments to control disease severity, the disease burden has serious implications for their health and quality of life [3–5].

Heightened capsaicin cough sensitivity is independently associated with poor asthma control in moderate-to-severe asthma patientshttps://bit.ly/3mkbLkI

Mechanisms and biomarkers of airway epithelial cell damage in asthma: A review

Bronchial asthma is a heterogeneous disease with complex pathological mechanisms representing different phenotypes, including severe asthma. The airway epithelium is a major site of complex pathological changes in severe asthma due, in part, to activation of inflammatory and immune mechanisms in response to noxious agents. Current imaging procedures are unable to accurately measure epithelial and airway remodeling. Damage of airway epithelial cells occurs is linked to specific phenotypes and endotypes which provides an opportunity for the identification of biomarkers reflecting epithelial, and airway, remodeling. Identification of patients with more severe epithelial disruption using biomarkers may also provide personalised therapeutic opportunities and/or markers of successful therapeutic intervention. Here, we review the evidence for ongoing epithelial cell dysregulation in the pathogenesis of asthma, the sentinel role of the airway epithelium and how understanding these molecular mechanisms provides the basis for the identification of candidate biomarkers for asthma prediction, prevention, diagnosis, treatment and monitoring.

Paediatrics: how to manage acute asthma exacerbations

Background

Asthma is the most common chronic disease of childhood and a major source of childhood health burden worldwide. These burdens are particularly marked when children experience characteristic ‘symptom flare-ups’ or acute asthma exacerbations (AAEs). AAE are associated with significant health and economic impacts, including acute Emergency Department visits, occasional hospitalizations, and rarely, death. To treat children with AAE, several medications have been studied and used.

Methods

We conducted a narrative review of the literature with the primary objective of understanding the evidence of their efficacy. We present this efficacy evidence in the context of a general stepwise management pathway for paediatric AAEs. This framework is developed from the combined recommendations of eight established (inter)national paediatric guidelines.

Discussion

Management of paediatric AAE centres around four major care goals: (1) immediate and objective assessment of AAE severity; (2) prompt and effective medical interventions to decrease respiratory distress and improve oxygenation; (3) appropriate disposition of patient; and (4) safe discharge plans. Several medications are currently recommended with varying efficacies, including heliox, systemic corticosteroids, first-line bronchodilators (salbutamol/albuterol), adjunctive bronchodilators (ipratropium bromide, magnesium sulfate) and second-line bronchodilators (aminophylline, i.v. salbutamol, i.v. terbutaline, epinephrine, ketamine). Care of children with AAE is further enhanced using clinical severity scoring, pathway-driven care and after-event discharge planning.

Conclusions

AAEs in children are primarily managed by medications supported by a growing body of literature. Continued efforts to study the efficacy of second-line bronchodilators, integrate AAE management with long-term asthma control and provide fair/equitable care are required.

Local drug delivery systems for inflammatory diseases: Status quo, challenges, and opportunities

Inflammation that is not resolved in due course becomes a chronic disease. The treatment of chronic inflammatory diseases involves a long-term use of anti-inflammatory drugs such as corticosteroids and nonsteroidal anti-inflammatory drugs, often accompanied by dose-dependent side effects. Local drug delivery systems have been widely explored to reduce their off-target side effects and the medication frequency, with several products making to the market or in development over the years. However, numerous challenges remain, and drug delivery technology is underutilized in some applications. This review showcases local drug delivery systems in different inflammatory diseases, including the targets well-known to drug delivery scientists (e.g., joints, eyes, and teeth) and other applications with untapped opportunities (e.g., sinus, bladder, and colon). In each section, we start with a brief description of the disease and commonly used therapy, introduce local drug delivery systems currently on the market or in the development stage, focusing on polymeric systems, and discuss the remaining challenges and opportunities in future product development.

Immunologic Pathophysiology and Airway Remodeling Mechanism in Severe Asthma: Focused on IgE-Mediated Pathways

Despite the expansion of the understanding in asthma pathophysiology and the continual advances in disease management, a small subgroup of patients remains partially controlled or refractory to standard treatments. Upon the identification of immunoglobulin E (IgE) and other inflammatory mediators, investigations and developments of targeted agents have thrived. Omalizumab is a humanized monoclonal antibody that specifically targets the circulating IgE, which in turn impedes and reduces subsequent releases of the proinflammatory mediators. In the past decade, omalizumab has been proven to be efficacious and well-tolerated in the treatment of moderate-to-severe asthma in both trials and real-life studies, most notably in reducing exacerbation rates and corticosteroid use. While growing evidence has demonstrated that omalizumab may be potentially beneficial in treating other allergic diseases, its indication remains confined to treating severe allergic asthma and chronic idiopathic urticaria. Future efforts may be bestowed on determining the optimal length of omalizumab treatment, seeking biomarkers that could better predict treatment response and as well as extending its indications.

NLRP1 variant M1184V decreases inflammasome activation in the context of DPP9 inhibition and asthma severity

Background

NLRP1 is an innate immune sensor that can form cytoplasmic inflammasome complexes. Polymorphisms in NLRP1 are linked to asthma; however, there is currently no functional or mechanistic explanation for this.

Objective

We sought to clarify the role of NLRP1 in asthma pathogenesis.

Methods

Results from the GALA II cohort study were used to identify a link between NLRP1 and asthma in Mexican Americans. In vitro and in vivo models for NLRP1 activation were applied to investigate the role of this inflammasome in asthma at the molecular level.

Results

We document the association of an NLRP1 haplotype with asthma for which the single nucleotide polymorphism rs11651270 (M1184V) individually is the most significant. Surprisingly, M1184V increases NLRP1 activation in the context of N-terminal destabilization, but decreases NLRP1 activation on dipeptidyl peptidase 9 inhibition. In vitro studies demonstrate that M1184V increases binding to dipeptidyl peptidase 9, which can account for its inhibitory role in this context. In addition, in vivo data from a mouse model of airway inflammation reveal a protective role for NLRP1 inflammasome activation reducing eosinophilia in this setting.

Conclusions

Linking our in vitro and in vivo results, we found that the NLRP1 variant M1184V reduces inflammasome activation in the context of dipeptidyl peptidase 9 inhibition and could thereby increase asthma severity. Our studies may have implications for the treatment of asthma in patients carrying this variant of NLRP1.

Steroid-Resistant Asthma and Neutrophils

Asthma patients are classified by phenotype and endotype. Although symptoms in most asthma patients are well controlled by glucocorticoid treatment, certain populations of severe eosinophilic asthma patients in T-helper 2 (Th2)/type 2 asthma and neutrophilic asthma patients in non-Th2/type 2 asthma show insensitivity to inhaled or oral glucocorticoid therapy. In some cases of severe eosinophilic asthma, eosinophils remain in the lungs despite glucocorticoid therapy. It was reported that interleukin (IL)-33-induced activation of type 2 innate lymphoid cells (ILC2) was resistant to glucocorticoid treatment in certain allergic conditions. Regarding neutrophilic airway inflammation in steroid-resistant asthma, IL-17 derived from Th17 cells and IL-8 and tumor necrosis factor-α derived mainly from macrophages were reported to be involved in the pathogenesis. Recently, "NETosis," a specific cell death of neutrophils, has been reported to be involved in asthmatic airway inflammation. When NETosis is induced in asthma, aggravation of inflammation and delay of tissue repair could occur, suggesting that NETosis may be associated with the development of steroid-resistant asthma. This article reviews the pathogenesis of steroid-resistant asthma by focusing mainly on neutrophils.

Amelioration of airway inflammation and pulmonary edema by Teucrium stocksianum via attenuation of pro-inflammatory cytokines and up-regulation of AQP1 and AQP5

Current study investigates the immunomodulatory effects of T. stocksianum using mouse model of ovalbumin (OVA)-induced allergic asthma. The mice were treated with methanolic extract, n-hexane, and ethyl acetate fractions for consecutive 7 days along with intranasal challenge. The mRNA expression levels of interleukin-4 (IL-4), IL-5, Aquaporin-1 (AQP1) and Aquaporin-5 (AQP5) were evaluated using reverse transcription polymerase chain reaction. The data showed that T. stocksianum significantly reduced airway inflammation as indicated by reduced inflammatory cell infiltration in lungs, and attenuated total and differential leukocyte counts both in blood and BALF. Expression levels of pro-inflammatory IL-4 and IL-5 in lungs were also found significantly reduced. T. stocksianum significantly reduced pulmonary edema as indicated by reduced lung wet/dry ratio and goblet cell hyperplasia. AQP1 and AQP5 expression levels were also found elevated in treatment groups. In conclusion, T. stocksianum possesses anti-asthmatic activity which may be attributed to reduction in IL-4 and IL-5 expression levels, and elevation in AQP1 and AQP5 expression levels.

Bidirectional interaction of airway epithelial remodeling and inflammation in asthma

Asthma is a chronic disease of the airways that has long been viewed predominately as an inflammatory condition. Accordingly, current therapeutic interventions focus primarily on resolving inflammation. However, the mainstay of asthma therapy neither fully improves lung function nor prevents disease exacerbations, suggesting involvement of other factors. An emerging concept now holds that airway remodeling, another major pathological feature of asthma, is as important as inflammation in asthma pathogenesis. Structural changes associated with asthma include disrupted epithelial integrity, subepithelial fibrosis, goblet cell hyperplasia/metaplasia, smooth muscle hypertrophy/hyperplasia, and enhanced vascularity. These alterations are hypothesized to contribute to airway hyperresponsiveness, airway obstruction, airflow limitation, and progressive decline of lung function in asthmatic individuals. Consequently, targeting inflammation alone does not suffice to provide optimal clinical benefits. Here we review asthmatic airway remodeling, focusing on airway epithelium, which is critical to maintaining a healthy respiratory system, and is the primary defense against inhaled irritants. In asthma, airway epithelium is both a mediator and target of inflammation, manifesting remodeling and resulting obstruction among its downstream effects. We also highlight the potential benefits of therapeutically targeting airway structural alterations. Since pathological tissue remodeling is likewise observed in other injury- and inflammation-prone tissues and organs, our discussion may have implications beyond asthma and lung disease.

CXCR1 and CXCR2 Inhibition by Ladarixin Improves Neutrophil-Dependent Airway Inflammation in Mice

Rationale

Increased IL-8 levels and neutrophil accumulation in the airways are common features found in patients affected by pulmonary diseases such as Asthma, Idiopathic Pulmonary Fibrosis, Influenza-A infection and COPD. Chronic neutrophilic inflammation is usually corticosteroid insensitive and may be relevant in the progression of those diseases.

Objective

To explore the role of Ladarixin, a dual CXCR1/2 antagonist, in several mouse models of airway inflammation with a significant neutrophilic component.

Findings

Ladarixin was able to reduce the acute and chronic neutrophilic influx, also attenuating the Th2 eosinophil-dominated airway inflammation, tissue remodeling and airway hyperresponsiveness. Correspondingly, Ladarixin decreased bleomycin-induced neutrophilic inflammation and collagen deposition, as well as attenuated the corticosteroid resistant Th17 neutrophil-dominated airway inflammation and hyperresponsiveness, restoring corticosteroid sensitivity. Finally, Ladarixin reduced neutrophilic airway inflammation during cigarette smoke-induced corticosteroid resistant exacerbation of Influenza-A infection, improving lung function and mice survival.

Conclusion

CXCR1/2 antagonist Ladarixin offers a new strategy for therapeutic treatment of acute and chronic neutrophilic airway inflammation, even in the context of corticosteroid-insensitivity.

Nocturnal temperature-controlled laminar airflow device for adults with severe allergic asthma: the LASER RCT

BACKGROUND

Severe asthma exacerbations are costly to patients and the NHS, and occur frequently in severely allergic patients.

OBJECTIVE

To ascertain whether or not nocturnal temperature-controlled laminar airflow (TLA) device usage over 12 months can reduce severe exacerbations and improve asthma control and quality of life compared with a placebo device, while being cost-effective and acceptable to adults with severe allergic asthma.

DESIGN

A pragmatic, multicentre, randomised, double-blind, placebo-controlled, parallel-group, superiority trial with qualitative interviews. The trial included an internal pilot with qualitative focus groups.

SETTING

Fourteen hospitals in the UK that manage patients with severe asthma.

PARTICIPANTS

Adults (16-75 years) with severe, poorly controlled, exacerbation-prone asthma despite high-intensity treatment, and who are sensitised to a perennial indoor aeroallergen.

INTERVENTION

Nocturnal, home-based TLA treatment using an Airsonett^® (Airsonett AB, Ängelholm, Sweden) device. The comparator was a placebo device that was identical to the active device except that it did not deliver the laminar airflow. Participants were allocated 1 : 1 to TLA therapy or placebo, minimised by site, origin of case, baseline severe exacerbation frequency, maintenance oral corticosteroid use and pre-bronchodilator forced expiratory volume in 1 second.

MAIN OUTCOME MEASURES

Primary outcome - frequency of severe asthma exacerbations occurring within the 12-month follow-up period, defined as worsening of asthma requiring systemic corticosteroids [≥ 30 mg of prednisolone or equivalent daily (or ≥ 50% increase in dose if on maintenance dose of ≥ 30 mg of prednisolone)] for ≥ 3 days. Secondary outcomes - changes in asthma control, lung function, asthma-specific and global quality of life for participants, adherence to the intervention, device acceptability, health-care resource use and cost-effectiveness.

RESULTS

Between May 2014 and January 2016, 489 patients consented to participate in the trial, of whom 249 failed screening and 240 were randomised (n = 119 in the treatment group and n = 121 in the placebo group); all were analysed. In total, 202 participants (84%) reported use of the device for 9-12 months. Qualitative analyses showed high levels of acceptability. The mean [standard deviation (SD)] rate of severe exacerbations did not differ between groups [active 1.39 (1.57), placebo 1.48 (2.03); risk ratio 0.92, 95% CI 0.66 to 1.27; p = 0.616]. There were no significant differences in secondary outcomes for lung function, except for a reduction in mean daily peak expiratory flow [mean (SD) difference 14.7 l/minute (7.35 l/minute), 95% CI 0.32 to 29.1 l/minute; p = 0.045) for those in the active device group. There were no differences in asthma control or airway inflammation and no serious harms related to the device. No significant difference between the groups in quality-adjusted life-years gained over 1 year was observed. In addition, there was no difference in generic or disease-specific health-related quality of life overall, although statistically significant higher quality of life at month 6 was observed. Increases in quality of life were not sufficient to offset the annual costs associated with use of the TLA device.

LIMITATIONS

Missing outcome data could have resulted in an underestimation of exacerbations and rendered the study inconclusive.

CONCLUSIONS

Within the limits of the data, no consistent benefits of the active device were demonstrated, and the differences observed were not sufficient to make the device cost-effective. The types of patients who may benefit from the TLA device, and the reasons for large reductions in exacerbation frequency in severe asthma trials, which also incorporate other methods of recording exacerbations, need to be explored.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN46346208.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 29. See the NIHR Journals Library website for further project information.

[Inhibitory Effects of Dabigatran on Airway Inflammation Induced by Lipopolysaccharide in Mice]

Asthma and chronic obstructive pulmonary disease (COPD) are characterised by chronic inflammation in the lung that is associated with airway obstruction. Inhaled therapy with a combination of corticosteroid and a long-acting β₂-agonist is an effective anti-inflammatory medicine for asthma, but in patients with severe asthma and COPD fails to completely control these symptoms with current therapies. The inflammatory process in these diseases, which involves activation of the coagulation and fibrinolytic system in the lung, offers the opportunity for alternative anti-inflammatory therapies. In this study, we investigated the effects of anti-coagulants on lipopolysaccharide (LPS)-induced airway inflammation in mice. A/J mice were exposed to LPS, a bacterial endotoxin, intranasally and accumulation of inflammatory cells, TNF-α, C-X-C motif chemokine (CXCL) 1, and osteopontin in bronchoalveolar lavage fluid (BALF) was monitored by flow cytometry and an enzyme-linked immunosorbent assay. LPS exposure induced airway neutrophilia and accumulation of TNF-α, CXCL1, and osteopontin in BALF. This LPS-induced airway inflammation was not relieved using a corticosteroid, fluticasone propionate (FP), or a direct inhibitor of Factor Xa, rivaroxaban. In contrast, a direct thrombin inhibitor, dabigatran, inhibited LPS-induced airway neutrophilia and decreased inflammatory cytokine production in a dose dependent manner. Furthermore, combination of dabigatran and FP elicited stronger inhibition of LPS-induced airway inflammation. Therefore, these results suggest that dabigatran could be an effective new therapy for severe respiratory diseases.

Personalised exhaled nitric oxygen fraction (F ENO)-driven asthma management in primary care: a F ENO subgroup analysis of the ACCURATE trial

Background

The aim of this study was to identify patients who benefit most from exhaled nitric oxide fraction (F_ENO)-driven asthma management in primary care, based on prespecified subgroups with different levels of F_ENO.

Methods

We used data from 179 adults with asthma from a 12-month primary care randomised controlled trial with 3-monthly assessments of F_ENO, asthma control, medication usage, costs of medication, severe asthma exacerbations and quality of life. In the original study, patients were randomised to either a symptom-driven treatment strategy (controlled asthma (Ca) strategy) or a F_ENO+symptom-driven strategy (FCa). In both groups, patients were categorised by their baseline level of F_ENO as low (<25 ppb), intermediate (25–50 ppb) and high (>50 ppb). At 12 months, we compared, for each prespecified F_ENO subgroup, asthma control, asthma-related quality of life, medication usage, and costs of medication between the Ca and FCa strategy.

Results

We found a difference between the Ca and FCa strategy for the mean dosage of beclomethasone strategy of 223 µg (95% CI 6–439), p=0.04) and for the total costs of asthma medication a mean reduction of US$159 (95% CI US$33–285), p=0.03) in patients with a low baseline F_ENO level. No differences were found for asthma control, severe asthma exacerbations and asthma-related quality of life in patients with a low baseline F_ENO level. Furthermore, in patients with intermediate or high level of F_ENO, no differences were found.

Conclusions

In primary care, F_ENO-driven asthma management is effective in patients with a low F_ENO level, for whom it is possible to down-titrate medication, while preserving asthma control and quality of life.

In primary care, F_ENO-driven asthma management is effective in patients with a low F_ENO, for whom it is possible to down-titrate medication while preserving asthma control and quality of lifehttps://bit.ly/2wC25N7d

Intranasal administration of budesonide-loaded nanocapsule microagglomerates as an innovative strategy for asthma treatment

The co-existence with rhinitis limits the control of asthma. Compared with oral H₁ receptor antagonists, intranasal corticosteroids have been demonstrated to provide greater relief of all symptoms of rhinitis and are recommended as first-line treatment for allergic rhinitis. Intrinsic limitations of nasal delivery, such as the presence of the protective mucous layer, the relentless mucociliary clearance, and the consequent reduced residence time of the formulation in the nasal cavity, limit budesonide efficacy to the treatment of local nasal symptoms. To overcome these limitations and to enable the treatment of asthma via nasal administration, we developed a budesonide-loaded lipid-core nanocapsule (BudNC) microagglomerate powder by spray-drying using a one-step innovative approach. BudNC was obtained, as a white powder, using L-leucine as adjuvant with 75 ± 6% yield. The powder showed a bimodal size distribution curve by laser diffraction with a principal peak just above 3 μm and a second one around 0.45 μm and a drug content determined by HPLC of 8.7 mg of budesonide per gram. In vivo after nasal administration, BudNC showed an improved efficacy in terms of reduction of immune cell influx; production of eotaxin-1, the main inflammatory chemokine; and arrest of airways remodeling when compared with a commercial budesonide product in both short- and long-term asthma models. In addition, data showed that the results in the long-term asthma model were more compelling than the results obtained in the short-term model. Graphical abstract.

Type 2 immunity in the skin and lungs

There has been extensive progress in understanding the cellular and molecular mechanisms of inflammation and immune regulation in allergic diseases of the skin and lungs during the last few years. Asthma and atopic dermatitis (AD) are typical diseases of type 2 immune responses. interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin are essential cytokines of epithelial cells that are activated by allergens, pollutants, viruses, bacteria, and toxins that derive type 2 responses. Th2 cells and innate lymphoid cells (ILC) produce and secrete type 2 cytokines such as IL-4, IL-5, IL-9, and IL-13. IL-4 and IL-13 activate B cells to class-switch to IgE and also play a role in T-cell and eosinophil migration to allergic inflammatory tissues. IL-13 contributes to maturation, activation, nitric oxide production and differentiation of epithelia, production of mucus as well as smooth muscle contraction, and extracellular matrix generation. IL-4 and IL-13 open tight junction barrier and cause barrier leakiness in the skin and lungs. IL-5 acts on activation, recruitment, and survival of eosinophils. IL-9 contributes to general allergic phenotype by enhancing all of the aspects, such as IgE and eosinophilia. Type 2 ILC contribute to inflammation in AD and asthma by enhancing the activity of Th2 cells, eosinophils, and their cytokines. Currently, five biologics are licensed to suppress type 2 inflammation via IgE, IL-5 and its receptor, and IL-4 receptor alpha. Some patients with severe atopic disease have little evidence of type 2 hyperactivity and do not respond to biologics which target this pathway. Studies in responder and nonresponder patients demonstrate the complexity of these diseases. In addition, primary immune deficiency diseases related to T-cell maturation, regulatory T-cell development, and T-cell signaling, such as Omenn syndrome, severe combined immune deficiencies, immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, and DOCK8, STAT3, and CARD11 deficiencies, help in our understanding of the importance and redundancy of various type 2 immune components. The present review aims to highlight recent advances in type 2 immunity and discuss the cellular sources, targets, and roles of type 2 mechanisms in asthma and AD.

Asthma immunotherapy and treatment approaches with mesenchymal stem cells

Asthma is a chronic inflammatory disease of the airways where exaggerated T helper 2 immune responses and inflammatory mediators play a role. Current asthma treatment options can effectively suppress symptoms and control the inflammatory process; however, cannot modulate the dysregulated immune response. Allergen-specific immunotherapy is one of the effective treatments capable of disease modification. Injecting allergens under the skin in allergen-specific immunotherapy can reduce asthma and improve the sensitivity of the lungs, however, has a risk of severe reactions. Mesenchymal stem cells have immunoregulatory activity with their soluble mediators and contact dependent manner. In this review, we focus on the current treatment strategies with mesenchymal stem cells in asthma as a new therapeutic tool and compare those with immunotherapy.

Airway Remodeling in Asthma

Asthma is an inflammatory disease of the airways that may result from exposure to allergens or other environmental irritants, resulting in bronchoconstriction, wheezing, and shortness of breath. The structural changes of the airways associated with asthma, broadly referred to as airway remodeling, is a pathological feature of chronic asthma that contributes to the clinical manifestations of the disease. Airway remodeling in asthma constitutes cellular and extracellular matrix changes in the large and small airways, epithelial cell apoptosis, airway smooth muscle cell proliferation, and fibroblast activation. These pathological changes in the airway are orchestrated by crosstalk of different cell types within the airway wall and submucosa. Environmental exposures to dust, chemicals, and cigarette smoke can initiate the cascade of pro-inflammatory responses that trigger airway remodeling through paracrine signaling and mechanostimulatory cues that drive airway remodeling. In this review, we explore three integrated and dynamic processes in airway remodeling: (1) initiation by epithelial cells; (2) amplification by immune cells; and (3) mesenchymal effector functions. Furthermore, we explore the role of inflammaging in the dysregulated and persistent inflammatory response that perpetuates airway remodeling in elderly asthmatics.

Development and validation of a new IgE-Tolerant ELISA method for quantifying serum concentration of omalizumab

BACKGROUND

Omalizumab is effectively used in asthma therapy, but ELISA methods used for omalizumab determination in blood from asthma patients may be interfered by the pre-existing IgE.

OBJECTIVE

To reduce the effect of pre-existing IgE on the omalizumab determination, the authors proposed a novel ELISA that can eliminate pre-existing IgE with by acid dissociation.

METHOD

The method was developed by dissociating the IgE-omalizumab complex with glacial acetic acid, and bio-IgE was added to bind the free omalizumab in serum, then bio-IgE-complex was captured by the immobilized streptavidin and detected by HRP-conjugated mouse anti-human IgG. Then a full validation of standard curve fitness, precision, accuracy, dilutional linearity, specificity, selectivity, stability, hook effect, and parallelism was performed. At last, the method was used in two studies in compliance with Good Laboratory Practice.

RESULTS

Correlation coefficient R² obtained from each calibration curve was 0.999 or 1.000 in the detection range of 0.1 μg/mL to 12.8 μg/mL. Results of precision, accuracy, dilutional linearity, specificity, selectivity, stability, hook effect, and parallelism were acceptable according to the ICH guideline M10. The method was successfully used in omalizumab determination in serum from 20 monkeys treated with 150 mg/kg omalizumab.

CONCLUSIONS

In conclusion, by dissociating IgE-omalizumab complex, the authors proposed for the first time a new validated IgE-tolerant ELISA assay to determine omalizumab concentration in serum samples.

Neutrophils from severe asthmatic patients induce epithelial to mesenchymal transition in healthy bronchial epithelial cells

BACKGROUND

Asthma is a heterogenous disease characterized by chronic inflammation and airway remodeling. An increase in the severity of airway remodeling is associated with a more severe form of asthma. There is increasing interest in the epithelial to mesenchymal transition process and mechanisms involved in the differentiation and repair of the airway epithelium, especially as they apply to severe asthma. Growing evidence suggests that Epithelial-Mesenchymal transition (EMT) could contribute to airway remodeling and fibrosis in asthma. Severe asthmatic patients with remodeled airways have a neutrophil driven inflammation. Neutrophils are an important source of TGF-β1, which plays a role in recruitment and activation of inflammatory cells, extracellular matrix (ECM) production and fibrosis development, and is a potent inducer of EMT.

OBJECTIVE

As there is little data examining the contribution of neutrophils and/or their mediators to the induction of EMT in airway epithelial cells, the objective of this study was to better understand the potential role of neutrophils in severe asthma in regards to EMT.

METHODS

We used an in vitro system to investigate the neutrophil-epithelial cell interaction. We obtained peripheral blood neutrophils from severe asthmatic patients and control subjects and examined for their ability to induce EMT in primary airway epithelial cells.

RESULTS

Our data indicate that neutrophils from severe asthmatic patients induce changes in morphology and EMT marker expression in bronchial epithelial cells consistent with the EMT process when co-cultured. TGF-β1 levels in the culture medium of severe asthmatic patients were increased compared to that from co-cultures of non-asthmatic neutrophils and epithelial cells.

CONCLUSIONS AND CLINICAL RELEVANCE

As an inducer of EMT and an important source of TGF-β1, neutrophils may play a significant role in the development of airway remodeling and fibrosis in severe asthmatic airways.

Awareness and Current Therapeutics of Asthma

Introduction:

Asthma is a serious allergic disorder of the respiratory system. It affects about 300 million people worldwide. This has a great burden on medical treatment. Several medicines are available, but they have many serious side effects. Therefore, there is a need to search for a new therapeutic agent with no or minimal side effects while most economical for patients. In folk medicine, antiasthmatics herbal medicine has been used and showed potential therapeutic antiasthmatic efficacy due to the presence of potential bioactive compounds.

Methods:

Different databases were searched (ie, Embase, PubMed, CBM, AMED, and CINAHL). We have reviewed the published data of the last 20 years. We used MeSH terms “asthma” herbal treatment of asthma, allopathic treatment of asthma, and treatment strategies for asthma. The traditional medicine was compared with modern medicine and the same pharmacotherapies alone or with placebo. The methodology was evaluated by using the GRADE summary of Finding tables and Cochrane Risk of Bias Tool.

Results:

There have been some clear-cut indications toward the recognition of further molecular and cellular mechanisms of asthma. Most of them recommend a further target for treatment. The novel procedures, biologics, and pharmaceuticals are evaluated. Both allopathic and herbal treatments of asthma are effective. Due to none or lesser side effects, herbal medicines are safer than conventional medicine.

Conclusion:

The preliminary documentation of the plants discussed in the review show the presence of several secondary metabolites that are responsible for the management of asthma and its relevant complications. Further research studies are needed to identify the bioactive compounds from these plants that have potential efficacy to cure asthma, and clinically based studies are needed to search for a complete cure for this disease.

Molecular changes during TGFβ-mediated lung fibroblast-myofibroblast differentiation: implication for glucocorticoid resistance

Airway remodeling is an important process in response to repetitive inflammatory-mediated airway wall injuries. This is characterized by profound changes and reorganizations at the cellular and molecular levels of the lung tissue. It is of particular importance to understand the mechanisms involved in airway remodeling, as this is strongly associated with severe asthma leading to devastating airway dysfunction. In this study, we have investigated the transforming growth factor-β (TGFβ, a proinflammatory mediator)-activated fibroblast to myofibroblast transdifferentiation pathway, which plays a key role in asthma-related airway remodeling. We show that TGFβ induces fibroblast to myofibroblast transdifferentiation by the expression of αSMA, a specific myofibroblast marker. Furthermore, Smad2/Smad3 gene and protein expression patterns are different between fibroblasts and myofibroblasts. Such a change in expression patterns reveals an important role of these proteins in the cellular phenotype as well as their regulation by TGFβ during cellular transdifferentiation. Interestingly, our data show a myofibroblastic TGFβ-mediated increase in glucocorticoid receptor (GR) expression and a preferential localization of GR in the nucleus, compared to in fibroblasts. Furthermore, the GRβ (nonfunctional GR isoform) is increased relative to GRα (functional isoform) in myofibroblasts. These results are interesting as they support the idea of a GRβ-mediated glucocorticoid resistance observed in the severe asthmatic population. All together, we provide evidence that key players are involved in the TGFβ-mediated fibroblast to myofibroblast transdifferentiation pathway in a human lung fibroblast cell line. These players could be the targets of new treatments to limit airway remodeling and reverse glucocorticoid resistance in severe asthma.

Development of highly potent glucocorticoids for steroid-resistant severe asthma

Clinical application of inhaled glucocorticoids (GCs) has been hampered in the case of steroid-resistant severe asthma. To overcome this limitation, we have developed a series of highly potent GCs, including VSGC12, VSG158, and VSG159 based on the structural insight into the glucocorticoid receptor (GR). Particularly, VSG158 exhibits a maximal repression of lung inflammation and is 10 times more potent than the currently most potent clinical GC, Fluticasone Furoate (FF), in a murine model of asthma. More importantly, VSG158 displays a unique property to reduce neutrophilic inflammation in a steroid-resistant airway inflammation model, which is refractory to clinically available GCs, including dexamethasone and FF. VSG158 and VSG159 are able to deliver effective treatments with reduced off-target and side effects. In addition, these GCs also display pharmacokinetic properties that are suitable for the inhalation delivery method for asthma treatment. Taken together, the excellent therapeutic and side-effect profile of these highly potent GCs holds promise for treating steroid-resistant severe asthma.

Allergen Sensitization and Asthma Outcomes among World Trade Center Rescue and Recovery Workers

A large number of World Trade Center (WTC) rescue and recovery workers are affected by asthma. While physical and mental health comorbidities have been associated with poor asthma control in this population, the potential role of allergen sensitization is unknown. This study examined the association of indoor sensitization and exposure as a risk factor for increased asthma morbidity in WTC workers. We used data from a prospective cohort of 331 WTC workers with asthma. Sensitization to indoor allergens was assessed by measurement of antigen-specific serum immunoglobulin E (IgE) levels. We used validated tools to evaluate the exposure to indoor allergens. Asthma morbidity outcomes included level of control (Asthma Control Questionnaire, ACQ), quality of life (Asthma Quality of Life Questionnaire, AQLQ) and acute resource utilization. The prevalence of sensitization to cat, dog, mouse, dust mite, cockroach, and mold allergens were 33%, 21%, 17%, 40%, 17%, and 17%, respectively. Unadjusted and regression analyses showed no significant relationship between sensitization and increased asthma morbidity (p > 0.05 for all comparisons), except for sensitization to Aspergillus Fumigatus, cat and mouse epithelium, which were associated with decreased morbidity.

Asthma Across Age: Insights From Primary Care

Asthma is a heterogeneous disease comprising of multiple phenotypes and affects patients from childhood up to old age. In this review, we summarize the current knowledge on the similarities and differences in asthma across different age-groups, with emphasis on the perspective from primary care. Despite the similar disease presentation, phenotyping studies showed that there are differences in the distribution of phenotypes of asthma presenting in childhood compared to that in adulthood. Whereas, asthma with early age of onset tends to be of the atopic phenotype, the disease shifts toward the non-atopic phenotypes at later ages. Studies within primary care patients aiming to elucidate risk factors for future asthma exacerbation have shown pediatric and elderly patients to be at higher risk for future asthma attacks compared to other adult patients. Regardless, both pediatric and adult studies demonstrated previous asthma episodes and severity, along with high blood eosinophil to predict subsequent asthma attacks. Differences in childhood and adult asthma are not limited to the underlying phenotypes but also extends to the challenges in the diagnosis, treatment, and management of the disease. Diagnosis of asthma is complicated by age-specific differential diagnoses such as infectious wheezing and nasal obstruction in children, and aging-related problems such as heart disease and obesity in the elderly. There are also age-related issues leading to decreased disease control such as non-adherence, tobacco use, difficulty in using inhalers and corticosteroid-related side effects which hinder asthma control at different patient age-groups. Several clinical guidelines are available to guide the diagnosis and drug prescription of asthma in pediatric patients. However, there are conflicting recommendations for the diagnostic tools and treatment for pediatric patients, posing additional challenges for primary care physicians in working with multiple guidelines. While tools such as spirometry and peak flow variability are often available in primary care, their usage in preschool patients is not consistently recommended. FeNO measurement may be a valuable non-invasive tool which can be adopted by primary physicians to assist asthma diagnosis in preschool-age patients.