Airway remodelling rather than cellular infiltration characterizes both type2 cytokine biomarker-high and -low severe asthma

Long-Term Clinical and Sustained REMIssion in Severe Eosinophilic Asthma Treated With Mepolizumab: The REMI-M Study

BACKGROUND

Biological therapies, such as mepolizumab, have transformed the treatment of severe eosinophilic asthma. Although mepolizumab's short-term effectiveness is established, there is limited evidence on its ability to achieve long-term clinical remission.

OBJECTIVE

To evaluate the long-term effectiveness and safety of mepolizumab, explore its potential to induce clinical and sustained remission, and identify baseline factors associated with the likelihood of achieving remission over 24 months.

METHODS

The REMIssion in Severe Eosinophilic Asthma Treated with Mepolizumab (REMI-M) is a retrospective, real-world, multicenter study that analyzed 303 patients with severe eosinophilic asthma who received mepolizumab. Clinical, demographic, and safety data were collected at baseline, 3, 6, 12, and 24 months. The most commonly used definitions of clinical remission, which included no exacerbations, no oral corticosteroid (OCS) use, and good asthma control with or without assessment of lung function parameters, were assessed. Sustained remission was defined as reaching clinical remission at 12 months and maintaining it until the end of the 24-month period.

RESULTS

Clinical remission rates ranged from 28.6% to 43.2% after 12 months and from 26.8% to 52.9% after 24 months based on the different remission definitions. The proportion of patients achieving sustained remission varied between 14.6% and 29%. Factors associated with the likelihood of achieving clinical remission included the presence of aspirin-exacerbated respiratory disease, better lung function at baseline, male sex, absence of anxiety/depression, gastroesophageal reflux disease, bronchiectasis, and reduced OCS consumption. Adverse events were infrequent.

CONCLUSIONS

This study demonstrates the real-world effectiveness of mepolizumab in achieving clinical remission and sustained remission in severe eosinophilic asthma over 24 months. The identification of distinct factors associated with the likelihood of achieving clinical remission emphasizes the importance of comprehensive management of comorbidities and timely identification of patients who may benefit from biologics.

Diagnostic value of serum thymus and activation-regulated chemokine (TARC) in fatal asthma

OBJECTIVES

Asthma, a chronic inflammatory airway disease, is characterized by airway hyperresponsiveness and structural changes. Accurate postmortem diagnosis is crucial because of legal and insurance implications, necessitating differentiation from other causes of sudden death. Thymus and activation-regulated chemokine (TARC) is a chemokine that potentially acts as a biomarker of asthma. This study evaluated the diagnostic value of serum TARC combined with immunoglobulin E (IgE) levels as biomarkers in forensic settings.

RESULTS

The subjects were 100 autopsy cases, categorized into fatal asthma (n = 25), acute myocardial infarction (AMI) (n = 37), and traumatic deaths (n = 38). TARC levels were significantly elevated in asthma (525.68 ± 801.87 pg/mL) compared with AMI (180.35 ± 109.37 pg/mL) and trauma (173.26 ± 105.01 pg/mL) cases. Similarly, serum IgE levels were higher in asthma (3363.72 ± 7023.46 KU/L) than in AMI (130.92 ± 260.79 KU/L) and trauma (134.53 ± 195.41 KU/L) cases. ROC curve analysis showed that serum TARC had a sensitivity of 68.0 % and specificity of 73.6 % (AUC 0.763, cut-off value of 225 pg/mL). In comparison, serum IgE had a sensitivity of 80 % and specificity of 86.1 % (AUC 0.881, cut-off value of 307 KU/L). The combined use of TARC and IgE increased the diagnostic specificity to 95.8 %.

CONCLUSIONS

Serum TARC and IgE are valuable biomarkers for diagnosing fatal asthma in forensic settings. While serum TARC levels correlate with Th2-mediated inflammation, the combined measurement of TARC and IgE enhances the diagnostic accuracy, providing significant specificity for confirming asthma diagnosis.

Surface-engineered mesenchymal stem cell for refractory asthma therapy: Reversing airway remodeling

In the development of asthma, subepithelial fibrosis and vascular proliferation cause airway remodeling and narrowing, leading to disease deterioration and respiratory failure. In the clinic, the treatment of asthma was aimed at reducing the frequency of acute asthma attacks through inhaled corticosteroids (ICSs). However, ICSs cannot prevent the progression into refractory asthma due to the formation of airway remodeling mainly by subepithelial fibrosis and angiogenesis surrounding the tracheal lumen. Herein, we constructed surface-engineered mesenchymal stem cells (MSCs/PVLA) via the bioconjugation of MSCs and reactive oxygen species-responsive polymeric micelles loaded with vactosertib (VST) and linifanib (LFN) for treating refractory asthma through reversing airway remodeling. MSCs/PVLA migrated to the tracheal lumen due to the inflammation tropism of MSCs, and subsequently released VST and LFN could inhibit the formation of airway remodeling by preventing subepithelial fibrosis and angiogenesis. Meanwhile, MSCs reduced inflammatory cell infiltration and cytokine secretion to regulate the pathological microenvironment. Our results suggested that MSCs/PVLA could serve as a promising candidate to prevent disease exacerbations and treat refractory asthma.

Airway tryptase levels inform the lack of clinical efficacy of the tryptase inhibitor MTPS9579A in asthma

BACKGROUND

Tryptase, a mast cell protease, has been identified as a potential therapeutic target in managing patients with refractory asthma. We assessed the efficacy, safety, pharmacokinetics, and pharmacodynamics of MTPS9579A, an anti-tryptase antibody, in a phase 2a randomized trial for patients with uncontrolled asthma and a phase 1c trial to understand activity within the lower respiratory tract.

METHODS

Phase 2a patients (n = 134) received 1800 mg MTPS9579A or placebo intravenously every 4 weeks for 48 weeks. The primary endpoint was time to the first composite exacerbation event. Phase 1c patients (n = 27) received one intravenous dose of 300 or 1800 mg MTPS9579A or placebo. Both trials measured MTPS9579A concentrations and effects on tryptase in serum and nasal lining fluid; phase 1c also analyzed bronchial lining fluid.

RESULTS

MTPS9579A did not meet the primary endpoint (hazard ratio = 0.90; 95% CI: 0.55-1.47; p = 0.6835); exacerbation rates in the placebo group were low. Serum and nasal MTPS9579A pharmacokinetics and tryptase levels were consistent with data from healthy volunteers. However, in phase 1c patients, compared to nasal levels, MTPS9579A bronchial concentrations were 6.8-fold lower, and bronchial active and total tryptase levels were higher (119-fold and 30-fold, respectively). Pharmacokinetic/pharmacodynamic modeling predicted intravenous doses of 3800 mg every 4 weeks would be necessary to achieve 95% active tryptase inhibition from baseline.

CONCLUSIONS

The MTPS9579A dose tested in the phase 2a study was insufficient to inhibit tryptase in bronchial lining fluid, likely contributing to the observed lack of efficacy.

Advances in non-type 2 severe asthma: from molecular insights to novel treatment strategies

Asthma is a prevalent pulmonary disease that affects more than 300 million people worldwide and imposes a substantial economic burden. While medication can effectively control symptoms in some patients, severe asthma attacks, driven by airway inflammation induced by environmental and infectious exposures, continue to be a major cause of asthma-related mortality. Heterogeneous phenotypes of asthma include type 2 (T2) and non-T2 asthma. Non-T2 asthma is often observed in patients with severe and/or steroid-resistant asthma. This review covers the molecular mechanisms, clinical phenotypes, causes and promising treatments of non-T2 severe asthma. Specifically, we discuss the signalling pathways for non-T2 asthma including the activation of inflammasomes, interferon responses and interleukin-17 pathways, and their contributions to the subtypes, progression and severity of non-T2 asthma. Understanding the molecular mechanisms and genetic determinants underlying non-T2 asthma could form the basis for precision medicine in severe asthma treatment.

The effects of inhaled corticosteroids on healthy airways

BACKGROUND

The effects of inhaled corticosteroids (ICS) on healthy airways are poorly defined.

OBJECTIVES

To delineate the effects of ICS on gene expression in healthy airways, without confounding caused by changes in disease-related genes and disease-related alterations in ICS responsiveness.

METHODS

Randomized open-label bronchoscopy study of high-dose ICS therapy in 30 healthy adult volunteers randomized 2:1 to (i) fluticasone propionate 500 mcg bd daily or (ii) no treatment, for 4 weeks. Laboratory staff were blinded to allocation. Biopsies and brushings were analysed by immunohistochemistry, bulk RNA sequencing, DNA methylation array and metagenomics.

RESULTS

ICS induced small between-group differences in blood and lamina propria eosinophil numbers, but not in other immunopathological features, blood neutrophils, FeNO, FEV1, microbiome or DNA methylation. ICS treatment upregulated 72 genes in brushings and 53 genes in biopsies, and downregulated 82 genes in brushings and 416 genes in biopsies. The most downregulated genes in both tissues were canonical markers of type-2 inflammation (FCER1A, CPA3, IL33, CLEC10A, SERPINB10 and CCR5), T cell-mediated adaptive immunity (TARP, TRBC1, TRBC2, PTPN22, TRAC, CD2, CD8A, HLA-DQB2, CD96, PTPN7), B-cell immunity (CD20, immunoglobulin heavy and light chains) and innate immunity, including CD48, Hobit, RANTES, Langerin and GFI1. An IL-17-dependent gene signature was not upregulated by ICS.

CONCLUSIONS

In healthy airways, 4-week ICS exposure reduces gene expression related to both innate and adaptive immunity, and reduces markers of type-2 inflammation. This implies that homeostasis in health involves tonic type-2 signalling in the airway mucosa, which is exquisitely sensitive to ICS.

The Role of Galectins in Asthma Pathophysiology: A Comprehensive Review

Galectins are a group of β-galactoside-binding proteins with several roles in immune response, cellular adhesion, and inflammation development. Current evidence suggest that these proteins could play a crucial role in many respiratory diseases such as pulmonary fibrosis, lung cancer, and respiratory infections. From this standpoint, an increasing body of evidence have recognized galectins as potential biomarkers involved in several aspects of asthma pathophysiology. Among them, galectin-3 (Gal-3), galectin-9 (Gal-9), and galectin-10 (Gal-10) are the most extensively studied in human and animal asthma models. These galectins can affect T helper 2 (Th2) and non-Th2 inflammation, mucus production, airway responsiveness, and bronchial remodeling. Nevertheless, while higher Gal-3 and Gal-9 concentrations are associated with a stronger degree of Th-2 phlogosis, Gal-10, which forms Charcot-Leyden Crystals (CLCs), correlates with sputum eosinophilic count, interleukin-5 (IL-5) production, and immunoglobulin E (IgE) secretion. Finally, several galectins have shown potential in clinical response monitoring after inhaled corticosteroids (ICS) and biologic therapies, confirming their potential role as reliable biomarkers in patients with asthma.

Airway hyperresponsiveness in asthma: The role of the epithelium

Airway hyperresponsiveness (AHR) is a key clinical feature of asthma. The presence of AHR in people with asthma provides the substrate for bronchoconstriction in response to numerous diverse stimuli, contributing to airflow limitation and symptoms including breathlessness, wheeze, and chest tightness. Dysfunctional airway smooth muscle significantly contributes to AHR and is displayed as increased sensitivity to direct pharmacologic bronchoconstrictor stimuli, such as inhaled histamine and methacholine (direct AHR), or to endogenous mediators released by activated airway cells such as mast cells (indirect AHR). Research in in vivo human models has shown that the disrupted airway epithelium plays an important role in driving inflammation that mediates indirect AHR in asthma through the release of cytokines such as thymic stromal lymphopoietin and IL-33. These cytokines upregulate type 2 cytokines promoting airway eosinophilia and induce the release of bronchoconstrictor mediators from mast cells such as histamine, prostaglandin D2, and cysteinyl leukotrienes. While bronchoconstriction is largely due to airway smooth muscle contraction, airway structural changes known as remodeling, likely mediated in part by epithelial-derived mediators, also lead to airflow obstruction and may enhance AHR. In this review, we outline the current knowledge of the role of the airway epithelium in AHR in asthma and its implications on the wider disease. Increased understanding of airway epithelial biology may contribute to better treatment options, particularly in precision medicine.

Possible role of HE4 level elevation in the pathogenesis of TH2-high asthma

OBJECTIVES

As a heterogeneous disease, asthma is characterized by airway hyperresponsiveness, airway inflammation, and airway mucus hypersecretion. According to the pathological changes, symptoms, preventive and treatment methods, asthma can be divided into TH2-high and TH2-low asthma. We show that the expression of the tumor biomarker human epididymis protein 4 (HE4) was significantly increased in TH2-high asthma group, while there was no marked difference in its expression between TH2-low asthma and healthy control groups. HE4 levels were significantly increased in plasma, induced sputum, and alveolar lavage fluid (BALF) samples and airway epithelial cells from TH2-high asthma group, showing that HE4 has a possible role in the pathogenesis of TH2-high asthma.

METHODS

Using RT-qPCR, ELISA, Western blot (WB), and immunohistochemistry, we assessed differences in HE4 expression in plasma, induced sputum, BALF, and airway epithelial cells among patients with the TH2-related asthma subtypes and healthy controls. To explore the role of HE4 in TH2-high asthma, we conducted a correlation analysis between HE4 levels in plasma, induced sputum, BALF, and airway epithelial cells and multiple indicators of airway eosinophilic inflammation, airway mucus secretion, and airway remodeling.

CONCLUSION

We found for the first time that HE4 was differentially expressed in the TH2-related asthma subtypes. In TH2-high asthma, HE4 levels were markedly elevated in airway epithelial cells, plasma, induced sputum, and BALF. HE4 may play an important role in various pathogenic mechanisms of asthma, such as airway eosinophilic inflammation, airway mucus secretion, and airway remodeling. HE4 in plasma may be a clinically biomarker for differentiating TH2-related asthma subtypes.

A real-world pharmacovigilance study of mepolizumab in the FDA adverse event reporting system (FAERS) database

Mepolizumab is primarily used in the treatment of asthma, eosinophilic granulomatosis with polyangiitis, eosinophilia syndrome, and chronic rhinitis with nasal polyps. The information about its adverse drug reactions is mainly derived from clinical trials, and there is a shortage of real-world studies with extensive sample sizes. In this study, the U.S. FDA's Adverse Event Reporting System (FAERS) database was analyzed to evaluate the side effects of mepolizumab. A total of 18,040 reports of mepolizumab-associated adverse events were identified from the FDA Adverse Event Reporting System database. Multiple disproportionality analysis algorithms were used to determine the significance of these AEs. The study identified 198 instances of mepolizumab-induced AEs, including some important AEs not mentioned in the product labeling. The time to onset of adverse reactions was also analyzed, with a median time of 109 days. Most AEs occurred within the first month of mepolizumab use, but some may still occur after 1 year of treatment. Gender-specific analysis showed different high-risk AEs for females (digestive and neurological side effects) and males (serious adverse effects leading to hospitalization and death). The findings mentioned provide valuable insights on optimizing the use of mepolizumab, enhancing its effectiveness, and minimizing potential side effects. This information will greatly contribute to the practical implementation of the drug in clinical settings.

Unraveling the Role of Epithelial Cells in the Development of Chronic Rhinosinusitis

The pathophysiology of CRS is multifactorial and complex yet needs to be completed. Recent evidence emphasizes the crucial part played by epithelial cells in the development of CRS. The epithelial cells act as physical barriers and play crucial roles in host defense, including initiating and shaping innate and adaptive immune responses. This review aims to present a comprehensive understanding of the significance of nasal epithelial cells in CRS. New research suggests that epithelial dysfunction plays a role in developing CRS through multiple mechanisms. This refers to issues with a weakened barrier function, disrupted mucociliary clearance, and irregular immune responses. When the epithelial barrier is compromised, it can lead to the passage of pathogens and allergens, triggering inflammation in the body. Furthermore, impaired mucociliary clearance can accumulate pathogens and secretions of inflammatory mediators, promoting chronic inflammation. Epithelial cells can release cytokines and chemokines, which attract and activate immune cells. This can result in an imbalanced immune response that continues to cause inflammation. The interaction between nasal epithelial cells and various immune cells leads to the production of cytokines and chemokines, which can either increase or decrease inflammation. By comprehending the role of epithelial cells in CRS, we can enhance our understanding of the disease's pathogenesis and explore new therapeutics.

Long-Term Real-World Outcomes of Mepolizumab and Benralizumab Among Biologic-Naive Patients With Severe Eosinophilic Asthma: Experience of 3 Years' Therapy

BACKGROUND

Biologic therapies such as mepolizumab and benralizumab offer treatment options for severe eosinophilic asthma (SEA), although long-term real-world data on their use are limited.

OBJECTIVES

To evaluate the impact of benralizumab and mepolizumab treatment among biologic-naive patients with SEA over 36 months and describe the incidence of super-response at 12 and 36 months, identifying potential predictive factors.

METHODS

We conducted a retrospective, single-center study of patients with SEA who were given mepolizumab or benralizumab from May 2017 to December 2019, and who completed 36 months of therapy. Baseline demographics, comorbidities, and medication use were described. Data on clinical outcomes, including maintenance oral corticosteroid (OCS) use, annual exacerbation rate (AER), mini Asthma Quality of Life Questionnaire, Asthma Control Questionnaire (ACQ-6), and eosinophil count were collected at baseline and at 12 and 36 months. Super-response was evaluated at 12 and 36 months.

RESULTS

A total of 81 patients were included. Maintenance OCS use significantly improved from baseline (5.3 mg/d) to 12 months (2.4 mg/d, P < .0001) and 36 months (0.6 mg/d; P < .0001). Annual exacerbation rate decreased from baseline (5.8) to 12 months (0.9; P < .0001) and 36 months (1.2; P < .0001). Mini Asthma Quality of Life Questionnaire, ACQ-6, and eosinophil count significantly improved from baseline to 12 and 36 months. Twenty-nine patients demonstrated super-response at 12 months. Compared with those without a super-response, these patients had better baseline AER (4.7 vs 6.5; P = .009), mini Asthma Quality of Life Questionnaire (3.41 vs 2.54; P = .002), and ACQ-6 (3.38 vs 4.06; P = .03) scores. Most maintained a super-response up to 36 months.

CONCLUSIONS

Mepolizumab and benralizumab are associated with significant improvements in OCS use, AER, and asthma control in real-world cohorts for up to 36 months, providing insight into long-term use for SEA.

Lactobacillus rhamnosus 76 alleviates airway inflammation in ovalbumin-allergic mice and improves mucus secretion by down-regulating STAT6/SPDEF pathway

Previous studies have reported a correlation between the dysregulation of intestinal microbiota and the occurrence of asthma. This study aimed to investigate the effect of probiotic Lactobacillus rhamnosus 76 (LR76) on ovalbumin (OVA)-allergic mice and the mechanism of LR76 affecting mucus secretion in asthma. OVA-allergic mice were supplemented with LR76, and 16HBE cells induced by interleukin-13 (IL-13) were treated with LR76 supernatant (LR76-s) to observe the effect of LR76. In OVA-sensitized mice, LR76 alleviated the inflammatory cell infiltration in lung tissue and reduced the inflammatory cell counts of BALF. The expression level of mRNA, including Il4, Il5, Il13, Il25, Tgfb1, Il10, and Ifng, was decreased in the lung tissue of mice in the LR76 group compared with the OVA group. MUC5AC expression was down-regulated, while SCGB1A1 was up-regulated in the lung tissue of OVA-allergic mice after being supplemented with LR76 and in 16HBE cells induced by IL-13 after incubating with LR76-s. LR76 and LR76-s down-regulated the expression of proteins, including STAT6, p-STAT6, and SPDEF, and mRNA of STAT6 and SPDEF. In conclusion, LR76 alleviated airway inflammation and Th2 response in OVA-allergic mice and improved the mucus secretion of mouse lung tissue and 16HBE cells in the asthma model by down-regulating STAT6/SPDEF pathway.

New insights into the pathophysiology and therapeutic targets of asthma and comorbid chronic rhinosinusitis with or without nasal polyposis

Asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) or without (CRSsNP) are chronic respiratory diseases. These two disorders often co-exist based on common anatomical, immunological, histopathological, and pathophysiological basis. Usually, asthma with comorbid CRSwNP is driven by type 2 (T2) inflammation which predisposes to more severe, often intractable, disease. In the past two decades, innovative technologies and detection techniques in combination with newly introduced targeted therapies helped shape our understanding of the immunological pathways underlying inflammatory airway diseases and to further identify several distinct clinical and inflammatory subsets to enhance the development of more effective personalized treatments. Presently, a number of targeted biologics has shown clinical efficacy in patients with refractory T2 airway inflammation, including anti-IgE (omalizumab), anti-IL-5 (mepolizumab, reslizumab)/anti-IL5R (benralizumab), anti-IL-4R-α (anti-IL-4/IL-13, dupilumab), and anti-TSLP (tezepelumab). In non-type-2 endotypes, no targeted biologics have consistently shown clinical efficacy so far. Presently, multiple therapeutical targets are being explored including cytokines, membrane molecules and intracellular signalling pathways to further expand current treatment options for severe asthma with and without comorbid CRSwNP. In this review, we discuss existing biologics, those under development and share some views on new horizons.

Neutrophil Extracellular Traps in Asthma: Friends or Foes?

Asthma is a chronic inflammatory disease characterized by variable airflow limitation and airway hyperresponsiveness. A plethora of immune and structural cells are involved in asthma pathogenesis. The roles of neutrophils and their mediators in different asthma phenotypes are largely unknown. Neutrophil extracellular traps (NETs) are net-like structures composed of DNA scaffolds, histones and granular proteins released by activated neutrophils. NETs were originally described as a process to entrap and kill a variety of microorganisms. NET formation can be achieved through a cell-death process, termed NETosis, or in association with the release of DNA from viable neutrophils. NETs can also promote the resolution of inflammation by degrading cytokines and chemokines. NETs have been implicated in the pathogenesis of various non-infectious conditions, including autoimmunity, cancer and even allergic disorders. Putative surrogate NET biomarkers (e.g., double-strand DNA (dsDNA), myeloperoxidase-DNA (MPO-DNA), and citrullinated histone H3 (CitH3)) have been found in different sites/fluids of patients with asthma. Targeting NETs has been proposed as a therapeutic strategy in several diseases. However, different NETs and NET components may have alternate, even opposite, consequences on inflammation. Here we review recent findings emphasizing the pathogenic and therapeutic potential of NETs in asthma.

Cellular senescence is increased in airway smooth muscle cells of elderly persons with asthma

Senescent cells can drive age-related tissue dysfunction partially via a senescence-associated secretory phenotype (SASP) involving proinflammatory and profibrotic factors. Cellular senescence has been associated with a structural and functional decline during normal lung aging and age-related diseases such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Asthma in the elderly (AIE) represents a major healthcare burden. AIE is associated with bronchial airway hyperresponsiveness and remodeling, which involves increased cell proliferation and higher rates of fibrosis, and resistant to standard therapy. Airway smooth muscle (ASM) cells play a major role in asthma such as remodeling via modulation of inflammation and the extracellular matrix (ECM) environment. Whether senescent ASM cells accumulate in AIE and contribute to airway structural or functional changes is unknown. Lung tissues from elderly persons with asthma showed greater airway fibrosis compared with age-matched elderly persons with nonasthma and young age controls. Lung tissue or isolated ASM cells from elderly persons with asthma showed increased expression of multiple senescent markers including phospho-p53, p21, telomere-associated foci (TAF), as well as multiple SASP components. Senescence and SASP components were also increased with aging per se. These data highlight the presence of cellular senescence in AIE that may contribute to airway remodeling.

Role of microRNAs in type 2 diseases and allergen-specific immunotherapy

MicroRNAs (miRs) have gained scientific attention due to their importance in the pathophysiology of allergic diseases as well as their potential as biomarkers in allergen-specific treatment options. Their function as post-transcriptional regulators, controlling various cellular processes, is of high importance since any single miR can target multiple mRNAs, often within the same signalling pathway. MiRs can alter dysregulated expression of certain cellular responses and contribute to or cause, but in some cases prevent or repress, the development of various diseases. In this review article, we describe current research on the role of specific miRs in regulating immune responses in epithelial cells and specialized immune cells in response to various stimuli, in allergic diseases, and regulation in the therapeutic approach of allergen-specific immunotherapy (AIT). Despite the fact that AIT has been used successfully as a causative treatment option since more than a century, very little is known about the mechanisms of regulation and its connections with microRNAs. In order to fill this gap, this review aims to provide an overview of the current knowledge.