Understanding Asthma Phenotypes, Endotypes, and Mechanisms of Disease

Heterogeneity, Bayesian thinking, and phenotyping in critical care: A primer

PURPOSE

To familiarize clinicians with the emerging concepts in critical care research of Bayesian thinking and personalized medicine through phenotyping and explain their clinical relevance by highlighting how they address the issues of frequent negative trials and heterogeneity of treatment effect.

SUMMARY

The past decades have seen many negative (effect-neutral) critical care trials of promising interventions, culminating in calls to improve the field's research through adopting Bayesian thinking and increasing personalization of critical care medicine through phenotyping. Bayesian analyses add interpretive power for clinicians as they summarize treatment effects based on probabilities of benefit or harm, contrasting with conventional frequentist statistics that either affirm or reject a null hypothesis. Critical care trials are beginning to include prospective Bayesian analyses, and many trials have undergone reanalysis with Bayesian methods. Phenotyping seeks to identify treatable traits to target interventions to patients expected to derive benefit. Phenotyping and subphenotyping have gained prominence in the most syndromic and heterogenous critical care disease states, acute respiratory distress syndrome and sepsis. Grouping of patients has been informative across a spectrum of clinically observable physiological parameters, biomarkers, and genomic data. Bayesian thinking and phenotyping are emerging as elements of adaptive clinical trials and predictive enrichment, paving the way for a new era of high-quality evidence. These concepts share a common goal, sifting through the noise of heterogeneity in critical care to increase the value of existing and future research.

CONCLUSION

The future of critical care medicine will inevitably involve modification of statistical methods through Bayesian analyses and targeted therapeutics via phenotyping. Clinicians must be familiar with these systems that support recommendations to improve decision-making in the gray areas of critical care practice.

Novel insights into the pleiotropic health effects of growth differentiation factor 11 gained from genome-wide association studies in population biobanks

BACKGROUND

Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor-β (TGF-β) superfamily that has gained considerable attention over the last decade for its observed ability to reverse age-related deterioration of multiple tissues, including the heart. Yet as many researchers have struggled to confirm the cardioprotective and anti-aging effects of GDF11, the topic has grown increasingly controversial, and the field has reached an impasse. We postulated that a clearer understanding of GDF11 could be gained by investigating its health effects at the population level.

METHODS AND RESULTS

We employed a comprehensive strategy to interrogate results from genome-wide association studies in population Biobanks. Interestingly, phenome-wide association studies (PheWAS) of GDF11 tissue-specific cis-eQTLs revealed associations with asthma, immune function, lung function, and thyroid phenotypes. Furthermore, PheWAS of GDF11 genetic variants confirmed these results, revealing similar associations with asthma, immune function, lung function, and thyroid health. To complement these findings, we mined results from transcriptome-wide association studies, which uncovered associations between predicted tissue-specific GDF11 expression and the same health effects identified from PheWAS analyses.

CONCLUSIONS

In this study, we report novel relationships between GDF11 and disease, namely asthma and hypothyroidism, in contrast to its formerly assumed role as a rejuvenating factor in basic aging and cardiovascular health. We propose that these associations are mediated through the involvement of GDF11 in inflammatory signaling pathways. Taken together, these findings provide new insights into the health effects of GDF11 at the population level and warrant future studies investigating the role of GDF11 in these specific health conditions.

Coinhibitory Molecule VISTA Play an Important Negative Regulatory Role in the Immunopathology of Bronchial Asthma

Objective

To investigate the significance of VISTA in bronchial asthma and its impact on the disease.

Methods

Human peripheral blood of asthma children was gathered. The expression concentrations of VISTA, IL-4, IL-6, CD25, CD40L, and PD-L2 in peripheral blood plasma were detected by ELISA. We established the mouse model of asthma and intervened with agonistic anti-VISTA mAb (4C11) and VISTA fusion protein. ELISA, flow cytometry, and Western blotting were performed to detect the expression levels of Th1, Th2, and Th17 cell subsets and related characteristic cytokines, as well as the protein levels of MAPKs, NF-κB, and TRAF6 in lung tissues. In addition, the infiltration of eosinophils and inflammatory cells, airway mucus secretion, and VISTA protein expression in lung histopathological sections of different groups of mice were analyzed.

Results

The concentration of VISTA in human asthma group decreased significantly (p < 0.05); A positive correlation was observed between VISTA and CD40L. The intervention of 4C11 mAb and fusion protein respectively during the induction period increase the differentiation of Th1 cells and the secretion of IFN-γ, and inhibit the differentiation of Th2 and Th17 cells, as well as the secretion of IL-4, IL-5, IL-13 and IL-17, partially reduce the pathological changes of asthma in mouse lungs and correct the progress of asthma. The MAPK, NF-κB, and TRAF6 protein levels were the middle range in the 4C11 mAb and fusion protein groups (p < 0.05).

Conclusion

The findings suggest VISTA may play a negative regulatory role in the occurrence and development of bronchial asthma.

Current Practices in Pediatric Asthma Care

This article is a comprehensive review of the latest knowledge and developments on pediatric asthma. It serves as a guide for general practitioners and subspecialists who treat asthma. The pathophysiology and critical features of asthma that should be addressed and the latest therapies available are discussed. The areas where further investigation is needed are also highlighted.

Type 2 Inflammation and Asthma in Children: A Narrative Review

Increased understanding of the underlying pathophysiology has highlighted the heterogeneity of asthma and identified that most children with asthma have type 2 inflammation with elevated biomarkers, such as blood eosinophils and/or fractional exhaled nitric oxide. Although in the past most of these children may have been categorized as having allergic asthma, identifying the type 2 inflammatory phenotype provides a mechanism to explain both allergic and non-allergic triggers in pediatric patients with asthma. Most children achieve control with low to medium doses of inhaled corticosteroids. However, in a small but significant proportion of children, asthma remains uncontrolled despite maximum conventional treatment, with an increased risk of severe exacerbations. In this review, we focus on the role of type 2 inflammation and allergic processes in children with asthma, together with evidence of the efficacy of available treatment options for those who experience severe symptoms.

Asthma and decreased lung function in children exposed to perfluoroalkyl and polyfluoroalkyl substances (PFAS): An updated meta-analysis unveiling research gaps

BACKGROUND AND OBJECTIVE

Associations between exposure to per- and polyfluoroalkyl substances (PFAS) and pediatric asthma and reduced lung function in children are mixed and inconclusive. The study objective was to examine the extant research on exposure to PFAS and the diagnosis of asthma or decreased lung function in children <17 years of age to highlight what is known and to identify research gaps for future investigations.

METHODS

The present review was registered on the PROSPER database (CRD42023407172). We systematically searched several bibliographic databases (Scopus, Embase, Web of Science (core Collection), Medline, and CINAHL) along with grey literature sources in January 2023 to find relevant studies before this date. The National Toxicology Program's Office of Health Assessment and Translation (NTP OHAT) tool was applied to assess the risk of bias (RoB) assessment. We used a random-effects meta-analysis to assess the associations. From 12 observational epidemiological studies (out of 513) explored for qualitative analyses, 4 studies were included in quantitative analyses.

RESULTS

The meta-analysis revealed a significant association between exposures to perfluorooctanoate (PFOA) with the prevalence of children's asthma [Odds Ratios (OR) = 1.162 (95% CI: 1.004-1.321)] whereas the association for perfluorooctane sulfonate (PFOS) was not statistically significant [OR = 1.03 (95%CI: 0.806-1.265]. The narrative synthesis results of the four included studies that examined the effects of PFAS exposure on lung function did not demonstrate significant associations between exposure to PFAS and decreased lung function. The RoB for most included studies was assessed as probably low without serious limitations. However, two studies were at high risk of biases.

CONCLUSION

Our findings suggest that children who are exposed to PFOA are at a higher risk of developing asthma as well as the association between exposure to PFOS with impaired lung function. Large longitudinal studies with homogeneous PFAS exposures and standardized outcome measures are needed to ascertain these outcomes with improved certainty as well as toxicological studies to investigate the underlying mechanisms.

Characterizing the Asthma Phenotype of Military Personnel

INTRODUCTION

Asthma is the most common diagnosis in military personnel who endorse chronic dyspnea. Service members have unique occupational risk factors, and there is concern that airborne exposures in the deployed environment as well as other occupational exposures may contribute to the development of asthma or exacerbate pre-existing disease. Asthma phenotyping with clinical biomarkers such as serum immunoglobulin E (IgE) levels and eosinophil (EOS) counts is useful in defining treatment strategies for the management of asthma. This study sought to characterize the phenotype of medically separated military personnel with career-limiting asthma to define potential management strategies and guide future research evaluating the unexplained prevalence of asthma in this population.

MATERIALS AND METHODS

A retrospective chart review of active duty service members (ADSM) who underwent fitness for duty evaluation via medical evaluation board between 2005 and 2016 and were separated with a minimum 30% conditional disability rating for asthma was performed. Only ADSM who were diagnosed with asthma by a pulmonologist and had spirometry data available were included in the analysis. Demographics, spirometry data, and laboratory data to include IgE levels, radioallergosorbent panels, and EOS counts were analyzed from the DoD electronic medical record.

RESULTS

A total of 141 service members were evaluated with a mean age of 42 ± 6.8 years, mean serum EOS count of 300 ± 358 cells/μL, and mean IgE level of 305 ± 363 IU/mL. The patients were further categorized into 4 subgroups based on serum EOS count and IgE level: group A with IgE < 100 IU/mL and EOS < 300 cells/μL (n = 45; 33%), group B with IgE > 100 IU/mL and EOS < 300 cells/μL (n = 44; 32%), group C with IgE < 100 IU/mL and EOS > 300 cells/μL (n = 6; 1%), and group D with IgE > 100 IU/mL, EOS > 300 cells/μL (n = 46; 34%). Among the cohorts, there were no statistically significant differences in demographics, body mass index, spirometry, smoking history, or disability rating.

CONCLUSION

The majority of ADSM with a defined asthma history do not have concordant elevations in serum IgE and blood EOS suggestive of a Th2-high phenotype. Asthma in this population is heterogeneous, and phenotyping using clinical biomarkers may be useful to define optimal treatment strategies.

Immunological and homeostatic pathways of alpha -1 antitrypsin: a new therapeutic potential

α -1 antitrypsin (A1AT) is a 52 kDa acute-phase glycoprotein belonging to the serine protease inhibitor superfamily (SERPIN). It is primarily synthesized by hepatocytes and to a lesser extent by monocytes, macrophages, intestinal epithelial cells, and bronchial epithelial cells. A1AT is encoded by SERPINA1 locus, also known as PI locus, highly polymorphic with at least 100 allelic variants described and responsible for different A1AT serum levels and function. A1AT inhibits a variety of serine proteinases, but its main target is represented by Neutrophil Elastase (NE). However, recent attention has been directed towards its immune-regulatory and homeostatic activities. A1AT exerts immune-regulatory effects on different cell types involved in innate and adaptive immunity. Additionally, it plays a role in metal and lipid metabolism, contributing to homeostasis. An adequate comprehension of these mechanisms could support the use of A1AT augmentation therapy in many disorders characterized by a chronic immune response. The aim of this review is to provide an up-to-date understanding of the molecular mechanisms and regulatory pathways responsible for immune-regulatory and homeostatic activities of A1AT. This knowledge aims to support the use of A1AT in therapeutic applications. Furthermore, the review summarizes the current state of knowledge regarding the application of A1AT in clinical and laboratory settings human and animal models.

Single-cell analysis identifies distinct CD4+ T cells associated with the pathobiology of pediatric obesity-related asthma

Pediatric obesity-related asthma is characterized by non-atopic T helper 1 (Th1) inflammation and steroid resistance. CDC42 upregulation in CD4+T cells underliesTh1 inflammation but the CD4+T cell subtype(s) with CDC42 upregulation and their contribution to steroid resistance are not known. Compared to healthy-weight asthma, obesity-alone and healthy-weight controls, single-cell transcriptomics of obese asthma CD4+T cells revealed CDC42 upregulation in 3 clusters comprised of naïve and central memory T cells, which differed from the cluster enriched for Th1 responses that was comprised of effector T cells. NR3C1, coding for glucocorticoid receptor, was downregulated, while genes coding for NLRP3 inflammasome were upregulated, in clusters with CDC42 upregulation and Th1 responses. Conserved genes in these clusters correlated with pulmonary function deficits in obese asthma. These findings suggest that several distinct CD4+T cell subtypes are programmed in obese asthma for CDC42 upregulation, Th1 inflammation, and steroid resistance, and together contribute to obese asthma phenotype.

Summary

CD4+T cells from obese children with asthma are distinctly programmed for non-allergic immune responses, steroid resistance and inflammasome activation, that underlie the obese asthma phenotype.

Predictive genetic panel for adult asthma using machine learning methods

Background

Asthma is a chronic inflammatory disease of the airways that is heterogeneous and multifactorial, making its accurate characterization a complex process. Therefore, identifying the genetic variations associated with asthma and discovering the molecular interactions between the omics that confer risk of developing this disease will help us to unravel the biological pathways involved in its pathogenesis.

Objective

We sought to develop a predictive genetic panel for asthma using machine learning methods.

Methods

We tested 3 variable selection methods: Boruta's algorithm, the top 200 genome-wide association study markers according to their respective P values, and an elastic net regression. Ten different algorithms were chosen for the classification tests. A predictive panel was built on the basis of joint scores between the classification algorithms.

Results

Two variable selection methods, Boruta and genome-wide association studies, were statistically similar in terms of the average accuracies generated, whereas elastic net had the worst overall performance. The predictive genetic panel was completed with 155 single-nucleotide variants, with 91.18% accuracy, 92.75% sensitivity, and 89.55% specificity using the support vector machine algorithm. The markers used range from known single-nucleotide variants to those not previously described in the literature. Our study shows potential in creating genetic prediction panels with tailored penalties per marker, aiding in the identification of optimal machine learning methods for intricate results.

Conclusions

This method is able to classify asthma and nonasthma effectively, proving its potential utility in clinical prediction and diagnosis.

Can probiotics be used in the prevention and treatment of bronchial asthma?

Asthma is a lifelong condition with varying degrees of severity and susceptibility to symptom control. Recent studies have examined the effects of individual genus, species, and strains of probiotic microorganisms on the course of asthma. The present review aims to provide an overview of current knowledge on the use of probiotic microorganisms, mainly bacteria of the genus Lactobacillus and Bifidobacterium, in asthma prevention and treatment. Recent data from clinical trials and mouse models of allergic asthma indicate that probiotics have therapeutic potential in this condition. Animal studies indicate that probiotic microorganisms demonstrate anti-inflammatory activity, attenuate airway hyperresponsiveness (AHR), and reduce airway mucus secretion. A randomized, double-blind, placebo-controlled human trials found that combining multi-strain probiotics with prebiotics yielded promising outcomes in the treatment of clinical manifestations of asthma. It appears that probiotic supplementation is safe and significantly reduces the frequency of asthma exacerbations, as well as improved forced expiratory volume and peak expiratory flow parameters, and greater attenuation of inflammation. Due to the small number of available clinical trials, and the use of a wide range of probiotic microorganisms and assessment methods, it is not possible to draw clear conclusions regarding the use of probiotics as asthma treatments.

Emerging Roles of Galectin-3 in Pulmonary Diseases

Galectin-3 is a multifunctional protein that is involved in various physiological and pathological events. Emerging evidence suggests that galectin-3 also plays a critical role in the pathogenesis of pulmonary diseases. Galectin-3 can be produced and secreted by various cell types in the lungs, and the overexpression of galectin-3 has been found in acute lung injury/acute respiratory distress syndrome (ALI/ARDS), pulmonary hypertension (PH), pulmonary fibrosis diseases, lung cancer, lung infection, chronic obstructive pulmonary disease (COPD), and asthma. Galectin-3 exerts diverse effects on the inflammatory response, immune cell activation, fibrosis and tissue remodeling, and tumorigenesis in these pulmonary disorders, and genetic and pharmacologic modulation of galectin-3 has therapeutic effects on the treatment of pulmonary illnesses. In this review, we summarize the structure and function of galectin-3 and the underlying mechanisms of galectin-3 in pulmonary disease pathologies; we also discuss preclinical and clinical evidence regarding the therapeutic potential of galectin-3 inhibitors in these pulmonary disorders. Additionally, targeting galectin-3 may be a very promising therapeutic approach for the treatment of pulmonary diseases.

Transcriptomic Expression of T2-Inflammation Genes in Peripheral Blood Mononuclear Cells and Longitudinal Clinical Outcomes in Asthma: Insights from the COREA Study

BACKGROUND

Gene expression can provide distinct information compared to clinical biomarkers in the context of longitudinal clinical outcomes in asthma patients.

OBJECTIVE

This study examined the association between the gene expression levels of upstream (IL-25, IL-33, and TSLP) and downstream cytokines (IL-5, IL-4, and IL-13) in the T2 inflammatory pathway with a 12-month follow-up of exacerbation, lung function, and steroid use.

METHODS

Transcriptomic sequencing analysis was performed on peripheral blood mononuclear cells from 279 adult asthmatics. Survival analysis and linear mixed-effect models were used to investigate potential differences between the high-level and low-level gene expression groups and the clinical outcomes. Analysis was performed separately for the upstream, downstream, and all 6 cytokines.

RESULTS

In general, T2 inflammatory cytokine gene expression showed a weak correlation with blood eosinophil counts (all r < 0.1) and clinical outcomes. Among moderate-to-severe eosinophilic asthma (MSEA) patients, individuals with elevated levels of downstream cytokines were at increased risk of time-to-first exacerbation (p = 0.044) and a greater increase of inhaled corticosteroid use over time (p = 0.002) compared to those with lower gene expression. There was no association between baseline T2 inflammatory cytokine gene expression and the longitudinal changes in lung function over time among MSEA patients.

CONCLUSION

These findings suggest that, among MSEA patients, the gene expression levels of downstream cytokines in the T2 inflammatory pathway may serve as indicators for endotyping asthma.

Unconventional Activation of IRE1 Enhances Th17 Responses and Promotes Airway Neutrophilia

Heightened unfolded protein responses (UPRs) are associated with the risk for asthma, including severe asthma. Treatment-refractory severe asthma manifests a neutrophilic phenotype with T helper (Th)17 responses. However, how UPRs participate in the deregulation of Th17 cells leading to neutrophilic asthma remains elusive. This study found that the UPR sensor IRE1 is induced in the murine lung with fungal asthma and is highly expressed in Th17 cells relative to naive CD4+ T cells. Cytokine (e.g., IL-23) signals induce the IRE1-XBP1s axis in a JAK2-dependent manner. This noncanonical activation of the IRE1-XBP1s pathway promotes UPRs and cytokine secretion by both human and mouse Th17 cells. Ern1 (encoding IRE1) deficiency decreases the expression of endoplasmic reticulum stress factors and impairs the differentiation and cytokine secretion of Th17 cells. Genetic ablation of Ern1 leads to alleviated Th17 responses and airway neutrophilia in a fungal airway inflammation model. Consistently, IL-23 activates the JAK2-IRE1-XBP1s pathway in vivo and enhances Th17 responses and neutrophilic infiltration into the airway. Taken together, our data indicate that IRE1, noncanonically activated by cytokine signals, promotes neutrophilic airway inflammation through the UPR-mediated secretory function of Th17 cells. The findings provide a novel insight into the fundamental understanding of IRE1 in Th17-biased TH2-low asthma.

Identification of severe acute pediatric asthma phenotypes using unsupervised machine learning

RATIONALE

More targeted management of severe acute pediatric asthma could improve clinical outcomes.

OBJECTIVES

To identify distinct clinical phenotypes of severe acute pediatric asthma using variables obtained in the first 12 h of hospitalization.

METHODS

We conducted a retrospective cohort study in a quaternary care children's hospital from 2014 to 2022. Encounters for children ages 2-18 years admitted to the hospital for asthma were included. We used consensus k means clustering with patient demographics, vital signs, diagnostics, and laboratory data obtained in the first 12 h of hospitalization.

MEASUREMENTS AND MAIN RESULTS

The study population included 683 encounters divided into derivation (80%) and validation (20%) sets, and two distinct clusters were identified. Compared to Cluster 1 in the derivation set, Cluster 2 encounters (177 [32%]) were older (11 years [8; 14] vs. 5 years [3; 8]; p < .01) and more commonly males (63% vs. 53%; p = .03) of Black race (51% vs. 40%; p = .03) with non-Hispanic ethnicity (96% vs. 84%; p < .01). Cluster 2 encounters had smaller improvements in vital signs at 12-h including percent change in heart rate (-1.7 [-11.7; 12.7] vs. -7.8 [-18.5; 1.7]; p < .01), and respiratory rate (0.0 [-20.0; 22.2] vs. -11.4 [-27.3; 9.0]; p < .01). Encounters in Cluster 2 had lower percentages of neutrophils (70.0 [55.0; 83.0] vs. 85.0 [77.0; 90.0]; p < .01) and higher percentages of lymphocytes (17.0 [8.0; 32.0] vs. 9.0 [5.3; 14.0]; p < .01). Cluster 2 encounters had higher rates of invasive mechanical ventilation (23% vs. 5%; p < .01), longer hospital length of stay (4.5 [2.6; 8.8] vs. 2.9 [2.0; 4.3]; p < .01), and a higher mortality rate (7.3% vs. 0.0%; p < .01). The predicted cluster assignments in the validation set shared the same ratio (~2:1), and many of the same characteristics.

CONCLUSIONS

We identified two clinical phenotypes of severe acute pediatric asthma which exhibited distinct clinical features and outcomes.

Chemical respiratory sensitization-Current status of mechanistic understanding, knowledge gaps and possible identification methods of sensitizers

Respiratory sensitization is a complex immunological process eventually leading to hypersensitivity following re-exposure to the chemical. A frequent consequence is occupational asthma, which may occur after long latency periods. Although chemical-induced respiratory hypersensitivity has been known for decades, there are currently no comprehensive and validated approaches available for the prospective identification of chemicals that induce respiratory sensitization, while the expectations of new approach methodologies (NAMs) are high. A great hope is that due to a better understanding of the molecular key events, new methods can be developed now. However, this is a big challenge due to the different chemical classes to which respiratory sensitizers belong, as well as because of the complexity of the response and the late manifestation of symptoms. In this review article, the current information on respiratory sensitization related processes is summarized by introducing it in the available adverse outcome pathway (AOP) concept. Potentially useful models for prediction are discussed. Knowledge gaps and gaps of regulatory concern are identified.

Immunological factors, important players in the development of asthma

Asthma is a heterogeneous disease, and its development is the result of a combination of factors, including genetic factors, environmental factors, immune dysfunction and other factors. Its specific mechanism has not yet been fully investigated. With the improvement of disease models, research on the pathogenesis of asthma has made great progress. Immunological disorders play an important role in asthma. Previously, we thought that asthma was mainly caused by an imbalance between Th1 and Th2 immune responses, but this theory cannot fully explain the pathogenesis of asthma. Recent studies have shown that T-cell subsets such as Th1 cells, Th2 cells, Th17 cells, Tregs and their cytokines contribute to asthma through different mechanisms. For the purpose of the present study, asthma was classified into distinct phenotypes based on airway inflammatory cells, such as eosinophilic asthma, characterized by predominant eosinophil aggregates, and neutrophilic asthma, characterized by predominant neutrophil aggregates. This paper will examine the immune mechanisms underlying different types of asthma, and will utilize data from animal models and clinical studies targeting specific immune pathways to inform more precise treatments for this condition.

Eosinophil-derived extracellular vesicles: isolation and classification techniques and implications for disease pathophysiology

Eosinophils are leukocytes characterized by their ability to release granule content that is highly rich in enzymes and proteins. Besides the antihelminthic, bactericidal, and antiviral properties of eosinophils and their secretory granules, these also play a prominent role in the pathophysiology of diseases such as asthma, eosinophilic esophagitis, and other hypereosinophilic conditions by causing tissue damage and airway hyperresponsiveness. Although this cell was first recognized mainly for its capacity to release granule content, nowadays other capabilities such as cytokine secretion have been linked to its physiology, and research has found that eosinophils are not only involved in innate immunity, but also as orchestrators of immune responses. Nearly 10 yr ago, eosinophil-derived extracellular vesicles (EVs) were first described; since then, the EV field has grown exponentially, revealing their vital roles in intracellular communication. In this review, we synthesize current knowledge on eosinophil-derived EVs, beginning with a description of what they are and what makes them important regulators of disease, followed by an account of the methodologies used to isolate and characterize EVs. We also summarize current understanding of eosinophil-derived vesicles functionality, especially in asthma, the disease in which eosinophil-derived EVs have been most widely studied, describing how they modulate the role of eosinophils themselves (through autocrine signaling) and the way they affect airway structural cells and airway remodeling. Deeper understanding of this cell type could lead to novel research in eosinophil biology, its role in other diseases, and possible use of eosinophil-derived EVs as therapeutic targets.

Modelling the innate immune system in microphysiological systems

This critical review aims to highlight how modeling of the immune response has adapted over time to utilize microphysiological systems. Topics covered here will discuss the integral components of the immune system in various human body systems, and how these interactions are modeled using these systems. Through the use of microphysiological systems, we have not only expanded on foundations of basic immune cell information, but have also gleaned insight on how immune cells work both independently and collaboratively within an entire human body system.

Healthcare Resource Utilisation of Severe Uncontrolled T2low and Non-T2low Asthma in Finland During 2018-2021

Purpose

Patients with asthma and low levels of type 2 inflammatory biomarkers (T2 low) have limited effective treatment options. Such biomarkers include eg blood eosinophils (b-eos) and fractional exhaled nitric oxide (FeNO). The healthcare resource utilisation (HCRU) of severe uncontrolled T2 low asthma remains unexplored. Thus, this study aimed to estimate the HCRU of T2 low and non-T2 low severe uncontrolled asthma patients using real-world data in Finland.

Patients and Methods

Adult patients with an asthma diagnosis during baseline (2012-2017) at the pulmonary department of Turku University Hospital were included and followed during 2018-2021, or until death. Total HCRU costs and respiratory-related HCRU costs were evaluated. The main drivers for the HCRU and costs were assessed with gamma and negative binomial regression models.

Results

Of the severe uncontrolled asthma patients with T2 status available, 40% (N=66) were identified with T2 low and 60% (N=103) with non-T2 low asthma. The average cumulative cost per patient was similar in patients with T2 low compared with non-T2 low, with all-cause costs cumulating in four years of follow-up to 37,524€ (95% CI: 27,160, 47,888) in T2 low compared to 34,712€ (25,484, 43,940) in non-T2 low. The corresponding average cumulative respiratory-related costs were 5178€ (3150, 7205) in T2 low compared to 5209€ (4104, 6313) in non-T2 low. Regression modelling identified no differences between the T2-status groups when assessing all-cause healthcare costs per patient-year (PPY). On the other hand, the regression modelling predicted more inpatient days PPY for severe uncontrolled patients with T2 low status compared to the patients with non-T2 low status.

Conclusion

Patients with uncontrolled severe T2 low asthma use equal healthcare resources as corresponding non-T2 low patients. This study brought new insights into the HCRU of severe uncontrolled asthma patients per T2 status, which has not previously been investigated.

Endotyping Chronic Respiratory Diseases: T2 Inflammation in the United Airways Model

Over the past 15 years, the paradigm of viewing the upper and lower airways as a unified system has progressively shifted the approach to chronic respiratory diseases (CRDs). As the global prevalence of CRDs continues to increase, it becomes evident that acknowledging the presence of airway pathology as an integrated entity could profoundly impact healthcare resource allocation and guide the implementation of pharmacological and rehabilitation strategies. In the era of precision medicine, endotyping has emerged as another novel approach to CRDs, whereby pathologies are categorized into distinct subtypes based on specific molecular mechanisms. This has contributed to the growing acknowledgment of a group of conditions that, in both the upper and lower airways, share a common type 2 (T2) inflammatory signature. These diverse pathologies, ranging from allergic rhinitis to severe asthma, frequently coexist and share diagnostic and prognostic biomarkers, as well as therapeutic strategies targeting common molecular pathways. Thus, T2 inflammation may serve as a unifying endotypic trait for the upper and lower airways, reinforcing the practical significance of the united airways model. This review aims to summarize the literature on the role of T2 inflammation in major CRDs, emphasizing the value of common biomarkers and integrated treatment strategies targeting shared molecular mechanisms.

Real-World Safety Profile of Biologic Drugs for Severe Uncontrolled Asthma: A Descriptive Analysis from the Spanish Pharmacovigilance Database

Background: The present investigation provides a thorough analysis of adverse drug reactions (ADRs) reported in the Database of the Spanish Pharmacovigilance System (FEDRA) for biologic medications primarily indicated for severe refractory asthma, including omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab. Our main objective was to identify ADRs not documented in the drugs' Technical Sheets (summary of product characteristics, SmPC), potentially indicating unrecognized risks meriting pharmacovigilance attention. Methods: Data spanning from each drug's market introduction until 22 January 2024, were analyzed, sourced from direct submissions to the Spanish Pharmacovigilance System, industry communications, and literature reviews. We evaluated notifications impartially to ensure a comprehensive review of all the ADRs associated with these medications. Results: This investigation underlines the critical role of post-marketing surveillance in enhancing patient safety. It emphasizes the necessity for healthcare professionals to report ADRs comprehensively to foster a robust pharmacovigilance system. Furthermore, the study highlights gaps between the reported ADRs and the information provided in SmPCs, signaling potential areas for improvement in drug safety monitoring and regulatory oversight. Conclusions: Finally, these findings may contribute to informed decision making in clinical practice and regulatory policy, ultimately advancing patient care and safety in the management of severe uncontrolled asthma.

Association between specific IgE to staphylococcal enterotoxin B and the eosinophilic phenotype of asthma

BACKGROUND/AIMS

Sensitization to staphylococcal superantigens (SAgs) could contribute to asthma severity. However, its relevance with eosinophilic phenotype has not yet been clarified. This study aimed to investigate associations between serum specific IgE levels to SAg and eosinophilic airway inflammation in adult asthmatics.

METHODS

The serum specific IgE levels to 3 SAgs, including staphylococcal enterotoxin A (SEA) and B (SEB), and toxic shock syndrome toxin-1 (TSST-1) were measured by ImmunoCAP in 230 adult asthmatic patients and 50 healthy controls (HCs). Clinical characteristics and laboratory parameters, including serum total/free IgE, and 2 eosinophil-activation markers, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN), were analyzed according to blood eosinophil counts (BEC; 150 cells/μL) and serum specific IgE levels to 3 SAgs (0.35 kU/L).

RESULTS

Asthmatic patients showed higher serum specific IgE levels to 3 SAgs than HCs (p < 0.05 for all). The serum total/clinfree IgE levels were significantly higher in asthmatics with positive IgE responses to 3 SAgs than those without (p < 0.05 for all). There were no significant differences in clinical parameters including age, asthma severity, comorbidities, or smoking according to IgE responses to 3 SAgs. Patients with positive IgE responses to SEB (not to SEA/TSST-1) had higher serum specific IgE levels to house dust mites and ECP/EDN as well as higher BEC with positive correlations between serum SEB-specific IgE levels and BEC/ECP/EDN (p < 0.05 for all).

CONCLUSION

These findings suggest that serum SEB-specific IgE levels could contribute to eosinophil activation as well as IgE production in adult asthma.

Pediatric Pharmacology for the Primary Care Provider: Advances and Limitations

Despite >1 in 5 children taking prescription drugs in the United States, off-label drug use is common. To increase the study of drugs in children, regulatory bodies have enacted legislation to incentivize and require pediatric drug studies. As a result of this legislation, novel trial approaches, and an increase in personnel with pediatric expertise, there have been numerous advancements in pediatric drug development. With this review, we aim to highlight developments in pediatric pharmacology over the past 6 years for the most common disease processes that may be treated pharmacologically by the pediatric primary care provider. Using information extracted from label changes between 2018 and 2023, the published literature, and Clinicaltrials.gov, we discuss advances across multiple therapeutic areas relevant to the pediatric primary care provider, including asthma, obesity and related disorders, mental health disorders, infections, and dermatologic conditions. We highlight instances in which new drugs have been developed on the basis of a deeper mechanistic understanding of illness and instances in which labels have been expanded in older drugs on the basis of newly available data. We then consider additional factors that affect pediatric drug use, including cost and nonpharmacologic therapies. Although there is work to be done, efforts focused on pediatric-specific drug development will increase the availability of evidence-based, labeled guidance for commonly prescribed drugs and improve outcomes through the safe and effective use of drugs in children.

Obesity and Asthma: Implementing a Treatable Trait Care Model

Recognition of obesity as a treatable trait of asthma, impacting its development, clinical presentation and management, is gaining widespread acceptance. Obesity is a significant risk factor and disease modifier for asthma, complicating treatment. Epidemiological evidence highlights that obese asthma correlates with poorer disease control, increased severity and persistence, compromised lung function and reduced quality of life. Various mechanisms contribute to the physiological and clinical complexities observed in individuals with obesity and asthma. These encompass different immune responses, including Type IVb, where T helper 2 cells are pivotal and driven by cytokines like interleukins 4, 5, 9 and 13, and Type IVc, characterised by T helper 17 cells and Type 3 innate lymphoid cells producing interleukin 17, which recruits neutrophils. Additionally, Type V involves immune response dysregulation with significant activation of T helper 1, 2 and 17 responses. Finally, Type VI is recognised as metabolic-induced immune dysregulation associated with obesity. Body mass index (BMI) stands out as a biomarker of a treatable trait in asthma, readily identifiable and targetable, with significant implications for disease management. There exists a notable gap in treatment options for individuals with obese asthma, where asthma management guidelines lack specificity. For example, there is currently no evidence supporting the use of incretin mimetics to improve asthma outcomes in asthmatic individuals without Type 2 diabetes mellitus (T2DM). In this review, we advocate for integrating BMI into asthma care models by establishing clear target BMI goals, promoting sustainable weight loss via healthy dietary choices and physical activity and implementing regular reassessment and referral as necessary.

State of the art: Alternative overlap syndrome-asthma and obstructive sleep apnea

In the general population, Bronchial Asthma (BA) and Obstructive Sleep Apnea (OSA) are among the most prevalent chronic respiratory disorders. Significant epidemiologic connections and complex pathogenetic pathways link these disorders via complex interactions at genetic, epigenetic, and environmental levels. The coexistence of BA and OSA in an individual likely represents a distinct syndrome, that is, a collection of clinical manifestations attributable to several mechanisms and pathobiological signatures. To avoid terminological confusion, this association has been named alternative overlap syndrome (vs overlap syndrome represented by the chronic obstructive pulmonary disease-OSA association). This comprehensive review summarizes the complex, often bidirectional links between the constituents of the alternative overlap syndrome. Cross-sectional, population, or clinic-based studies are unlikely to elucidate causality or directionality in these relationships. Even longitudinal epidemiological evaluations in BA cohorts developing over time OSA, or OSA cohorts developing BA during follow-up cannot exclude time factors or causal influence of other known or unknown mediators. As such, a lot of pathophysiological interactions described here have suggestive evidence, biological plausibility, potential or actual directionality. By showcasing existing evidence and current knowledge gaps, the hope is that deliberate, focused, and collaborative efforts in the near-future will be geared toward opportunities to shine light on the unknowns and accelerate discovery in this field of health, clinical care, education, research, and scholarly endeavors.

Information theory reveals physiological manifestations of COVID-19 that correlate with symptom density of illness

Algorithms for the detection of COVID-19 illness from wearable sensor devices tend to implicitly treat the disease as causing a stereotyped (and therefore recognizable) deviation from healthy physiology. In contrast, a substantial diversity of bodily responses to SARS-CoV-2 infection have been reported in the clinical milieu. This raises the question of how to characterize the diversity of illness manifestations, and whether such characterization could reveal meaningful relationships across different illness manifestations. Here, we present a framework motivated by information theory to generate quantified maps of illness presentation, which we term "manifestations," as resolved by continuous physiological data from a wearable device (Oura Ring). We test this framework on five physiological data streams (heart rate, heart rate variability, respiratory rate, metabolic activity, and sleep temperature) assessed at the time of reported illness onset in a previously reported COVID-19-positive cohort (N = 73). We find that the number of distinct manifestations are few in this cohort, compared to the space of all possible manifestations. In addition, manifestation frequency correlates with the rough number of symptoms reported by a given individual, over a several-day period prior to their imputed onset of illness. These findings suggest that information-theoretic approaches can be used to sort COVID-19 illness manifestations into types with real-world value. This proof of concept supports the use of information-theoretic approaches to map illness manifestations from continuous physiological data. Such approaches could likely inform algorithm design and real-time treatment decisions if developed on large, diverse samples.

Obesity Enhances Non-Th2 Airway Inflammation in a Murine Model of Allergic Asthma

Obese patients with asthma present with aggravated symptoms that are also harder to treat. Here, we used a mouse model of allergic asthma sensitised and challenged to house dust mite (HDM) extracts to determine whether high-fat-diet consumption would exacerbate the key features of allergic airway inflammation. C57BL/6 mice were intranasally sensitised and challenged with HDM extracts over a duration of 3 weeks. The impact of high-fat-diet (HFD) vs. normal diet (ND) chow was studied on HDM-induced lung inflammation and inflammatory cell infiltration as well as cytokine production. HFD-fed mice had greater inflammatory cell infiltration around airways and blood vessels, and an overall more severe degree of inflammation than in the ND-fed mice (semiquantitative blinded evaluation). Quantitative assessment of HDM-associated Th2 responses (numbers of lung CD4+ T cells, eosinophils, serum levels of allergen-specific IgE as well as the expression of Th2 cytokines (Il5 and Il13)) did not show significant changes between the HFD and ND groups. Interestingly, the HFD group exhibited a more pronounced neutrophilic infiltration within their lung tissues and an increase in non-Th2 cytokines (Il17, Tnfa, Tgf-b, Il-1b). These findings provide additional evidence that obesity triggered by a high-fat-diet regimen may exacerbate asthma by involving non-Th2 and neutrophilic pathways.

Omalizumab in combination with subcutaneous immunotherapy for the treatment of multiple allergies associated with attention-deficit/hyperactivity disorder: a case report and a literature review

We describe the case of a 10-year-old boy with asthma (AS), accompanied by allergic rhinitis (AR), food allergy (FA), and combined attention-deficit/hyperactivity disorder (ADHD), who was treated at Shanghai Renji Hospital on 11 July 2020. The efficiency of the previous treatment with salmeterol/ticlosone was poor. Treatment with montelukast sodium resulted in development of neurological symptoms. Treatment with omalizumab in combination with subcutaneous immunotherapy (SCIT) was then initiated in our department based on anti-asthmatic therapy. Symptoms of asthma were completely controlled, and FA and AR symptoms improved. The treatment regimen led to a significant improvement in ADHD symptoms and the overall quality of life of the patient. The literature search was done in the PubMed database using "attention deficit/hyperactivity disorder/ADHD" and "asthma" as keywords, and we identified 47 relevant articles. In conclusion, our results show that treating asthma with omalizumab in combination with salmeterol/ticlosone and SCIT is efficient in controlling symptoms of multiple allergies and may lead to the improvement in ADHD symptoms and the overall quality of life of pediatric patients with ADHD. While current studies suggest that allergic diseases are closely related to ADHD, there is still a lack of studies or case reports of complete treatment protocols to provide clinical clues for management of the disease.

Navigating biologic therapies in elderly asthma

The prevalence of asthma among the elderly population has witnessed a notable rise, presenting unique challenges in diagnosis and management. Biologic therapies, such as omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab, have demonstrated efficacy in targeting specific pathways associated with severe asthma in elderly individuals. However, a significant research gap exists in the application of these therapies in elderly asthma patients. Despite the considerable size of the elderly asthma population and the social and economic burden that this specific demographic imposes on society, the available body of research catering to this group is limited. Notably, no RCTs have been expressly designed for the elderly across all asthma biologic therapies. Moreover, most RCTs have set upper age cutoffs, commonly 75 years old, and exclusion criteria for common comorbidities in the elderly, thus marginalizing this group from pivotal research. This underscores the crucial need for intentional inclusion of elderly participants in separately designed clinical trials and more researches, aiming to augment the generalizability of findings and enhance therapeutic outcomes. Given the distinct physiological changes associated with aging, there may be a concern regarding the efficacy and safety of biologic therapies in the elderly compared to non-elderly adults, posing a barrier to their use in this population. However, observational studies have shown similar benefits of these therapies in elderly individuals as seen in non-elderly adults. Other anticipated challenges related to initiating biologic therapy in elderly people with asthma including dosing consideration and monitoring strategies, which are important areas of investigation for optimizing asthma management will be discussed in this review. In summary, this review navigates the current landscape of biologic therapies for elderly asthma, offering valuable insights for various stakeholders, including researchers, healthcare providers, and policymakers, to advance asthma care in this vulnerable population. We propose that future research should concentrate on tailored, evidence-based approaches to address the undertreatment of elderly asthma patients.

Skin, gut, and lung barrier: Physiological interface and target of intervention for preventing and treating allergic diseases

The epithelial barriers of the skin, gut, and respiratory tract are critical interfaces between the environment and the host, and they orchestrate both homeostatic and pathogenic immune responses. The mechanisms underlying epithelial barrier dysfunction in allergic and inflammatory conditions, such as atopic dermatitis, food allergy, eosinophilic oesophagitis, allergic rhinitis, chronic rhinosinusitis, and asthma, are complex and influenced by the exposome, microbiome, individual genetics, and epigenetics. Here, we review the role of the epithelial barriers of the skin, digestive tract, and airways in maintaining homeostasis, how they influence the occurrence and progression of allergic and inflammatory conditions, how current treatments target the epithelium to improve symptoms of these disorders, and what the unmet needs are in the identification and treatment of epithelial disorders.

Towards personalized medicine for the treatment of equine asthma

Although horses with asthma share similar clinical signs, the heterogeneity of the disease in terms of severity, triggering factors, inflammatory profile, and pathological features has hindered our ability to define biologically distinct subgroups. The recognition of phenotypes and endotypes could enable the development of precision medicine, including personalized, targeted therapy, to benefit affected horses. While in its infancy in horses, this review outlines the phenotypes of equine asthma and discusses how knowledge gained from targeted therapy in human medicine can be applied to evaluate the potential opportunities for personalized medicine in equine asthma and to suggest avenues for research to advance this emerging field.

Contribution of Obstructive Sleep Apnea to Asthmatic Airway Inflammation and Impact of Its Treatment on the Course of Asthma

Asthma and obstructive sleep apnea (OSA) are very common respiratory disorders in the general population. Beyond their high prevalence, shared risk factors, and genetic linkages, bidirectional relationships between asthma and OSA exist, each disorder affecting the other's presence and severity. The author reviews here some of the salient links between constituents of the alternative overlap syndrome, that is, OSA comorbid with asthma, with an emphasis on the effects of OSA or its treatment on inflammation in asthma. In the directional relationship from OSA toward asthma, beyond direct influences, multiple factors and comorbidities seem to contribute.

Research on the Mechanism and Application of Acupuncture Therapy for Asthma: A Review

Asthma is a high-risk disease based on airway hyperresponsiveness (AHR). In this review, we found that there are many studies on clinical therapy for asthma that focus on the efficacy of acupuncture therapy and its mechanisms, including the functional connectivity of different brain regions, with the aid of functional magnetic resonance imaging (fMRI), immune responses/cell recognition (innate lymphoid cells and balance of Th1/Th2 and Treg/Th17), intracellular mechanism (autophagy, endoplasmic reticulum stress, and epigenetic alteration), and ligand-receptor/chemical signaling pathway (neurotransmitter, hormone, and small molecules). In this review, we summarized the clinical and experimental evidence for the mechanisms of acupuncture therapy in asthma to offer insights into drug discovery and clinical therapy. Given the paucity of clinical studies on the mechanisms of acupuncture in the treatment of asthma, this review notably included studies based on animal models to investigate the mechanisms of acupuncture in the treatment of asthma.

EndoPRS: Incorporating Endophenotype Information to Improve Polygenic Risk Scores for Clinical Endpoints

Polygenic risk score (PRS) prediction of complex diseases can be improved by leveraging related phenotypes. This has motivated the development of several multi-trait PRS methods that jointly model information from genetically correlated traits. However, these methods do not account for vertical pleiotropy between traits, in which one trait acts as a mediator for another. Here, we introduce endoPRS, a weighted lasso model that incorporates information from relevant endophenotypes to improve disease risk prediction without making assumptions about the genetic architecture underlying the endophenotype-disease relationship. Through extensive simulation analysis, we demonstrate the robustness of endoPRS in a variety of complex genetic frameworks. We also apply endoPRS to predict the risk of childhood onset asthma in UK Biobank by leveraging a paired GWAS of eosinophil count, a relevant endophenotype. We find that endoPRS significantly improves prediction compared to many existing PRS methods, including multi-trait PRS methods, MTAG and wMT-BLUP, which suggests advantages of endoPRS in real-life clinical settings.

Current Challenges in Pediatric Asthma

Asthma is a chronic lung disease characterized by reversible bronchoconstriction and inflammation of the bronchi. Its increasing prevalence in childhood as well as different triggers make asthma a challenging disease in several ways: defining its phenotype/endotype, the diagnostic approach (especially in younger children), therapeutic options, and systematic follow-up. Considering these problems, this review approaches the current status and limitations of guidelines used for asthma management in children. It also emphasizes the key points which could lead to a better understanding and the direction to take in future studies.

Heat-killed Akkermansia muciniphila ameliorates allergic airway inflammation in mice

Allergic asthma (AA) is a common inflammatory airway disease characterized by increased airway hyper-responsiveness (AHR), inflammation, and remodeling. Akkermansia muciniphila is a strictly anaerobic bacterium residing in the gut and is a promising next-generation probiotic to improve metabolic inflammatory syndrome. A recent study suggested the beneficial effect of live A. muciniphila on allergic airway inflammation (AAI) in mice. However, whether the heat-killed form can improve AAI requires further investigation. Mice sensitized and challenged with house dust mites (HDM) develop AA hallmarks including inflammatory cell infiltration, goblet cell hyperplasia, and subepithelial collagen deposition in the lungs. These phenomena were reversed by oral administration of the heat-killed A. muciniphila strain EB-AMDK19 (AMDK19-HK) isolated from the feces of healthy Koreans. Furthermore, AMDK19-HK diminished the HDM-induced AHR to inhaled methacholine, lung mast cell accumulation, and serum HDM-specific IgE levels. It also led to the overall suppression of IL-4, IL-13, and eotaxin production in bronchoalveolar lavage fluids, and Il4, Il5, Il13, and Ccl17 gene expression in lung tissues. Moreover, AMDK19-HK suppressed Th2-associated cytokine production in the splenocytes of HDM-sensitized mice in vitro. Additionally, a combination of 16S rRNA gene sequencing and short-chain fatty acid (SCFA) analysis in cecal samples revealed that AMDK19-HK modulated the relative abundance of circulating SCFA-associated gut genera, including a positive correlation with Lachnospiraceae_ NK4A136_group and a negative correlation with Lachnoclostridium and significantly increased cecal SCFA concentrations. Finally, AMDK19-HK improved intestinal mucosal barrier function. These results suggest that the oral administration of AMDK19-HK ameliorates HDM-induced AAI in mice by suppressing Th2-mediated immune responses and could have a protective effect against AA development.

Pycnogenol® French maritime pine bark extract in randomized, double-blind, placebo-controlled human clinical studies

Pycnogenol® French maritime pine bark extract is a well-known and thoroughly studied patented extract from the bark of Pinus pinaster Ait. ssp. Atlantica. In 39 randomized double-blind, placebo-controlled (RDP) human clinical trials including 2,009 subjects, Pycnogenol® French maritime pine bark extract supplementation for two weeks to six months has been shown to beneficially affect cardiovascular health, chronic venous insufficiency, cognition, joint health, skin health, eye health, women's health, respiratory health and allergies, oral health and sports performance. The mechanisms of action that can explain the respective effects on different conditions in the human body are discussed as well. As investigated in several in vitro, in vivo and in clinical studies, Pycnogenol® French maritime pine bark extract showed antioxidative effects, anti-inflammatory abilities, beneficial effects on endothelial function and reinforcing effects on the extracellular matrix. The present review aims to give a comprehensive overview of currently available "gold standard" RDP trials of Pycnogenol®'s benefits across various health domains compared to placebo. In addition, some of the processes on which the presented effects of Pycnogenol® French maritime pine bark extract are based will be elucidated and discussed. This broad overview of RDP studies on Pycnogenol® in different health domains can be used as a basis for further research on applications and mechanisms of this unique French maritime pine bark extract.

Fiber rich food suppressed airway inflammation, GATA3 + Th2 cells, and FcεRIα+ eosinophils in asthma

Background

Allergic Asthma is a disease presenting various endotypes and no current therapies act curative but alleviate disease symptoms. Dietary interventions are gaining increasing importance in regulating immune responses. Furthermore, short chain fatty acids (SFCA), as the main products of dietary fiber's fermentation by the gut bacteria, ameliorate the pathogenesis and disease burden of different illnesses including asthma. Nevertheless, the connection and crosstalk between the gut and lung is poorly understood.

Objective

In this work, the role of high fiber diet on the development of allergic asthma at baseline and after exacerbation of disease induced by respiratory viruses was investigated.

Methods

Hereby, SCFA in serum of asthmatic and non-asthmatic pre-school children before and after airway disease symptoms were analyzed. Moreover, the effect of high fiber diet in vivo in a murine model of house dust mite extract (HDM) induced allergic asthma and in the end in isolated lung and spleen cells infected ex vivo with Rhinovirus was analyzed.

Results

In this study, a decrease of the SCFA 3-Hydroxybutyric acid in serum of asthmatic children after symptomatic episodes at convalescent visit as compared to asthmatic and control children at baseline visit was observed. In experimental asthma, in mice fed with high fiber diet, a reduced lung GATA3 + Th2 type mediated inflammation, mucus production and collagen deposition and expression of Fc epsilon receptor Ia (FcεRIa) in eosinophils was observed. By contrast, the CD8+ memory effector T cells were induced in the lungs of asthmatic mice fed with high fiber diet. Then, total lung cells from these asthmatic mice fed with either standard food or with fiber rich food were infected with RV ex vivo. Here, RV1b mRNA was found significantly reduced in the lung cells derived from fiber rich food fed mice as compared to those derived from standard food fed asthmatic mice. Looking for the mechanism, an increase in CD8+ T cells in RV infected spleen cells derived from fiber rich fed asthmatic mice, was observed.

Conclusion

Convalescent preschool asthmatic children after a symptomatic episode have less serum ß-Hydroxybutyric acid as compared to control and asthmatic children at baseline visit. Fiber rich diet associated with anti-inflammatory effects as well as anti-allergic effects by decreasing Type 2 and IgE mediated immune responses and inducing CD8+ memory effector T cells in a murine model of allergic asthma. Finally, ex vivo infection with Rhinovirus (RV) of total lung cells from asthmatic mice fed with fiber rich food led to a decreased RV load as compared to mice fed with standard food. Moreover, spleen cells derived from asthmatic mice fed with fiber rich food induced CD8+ T cells after ex vivo infection with RV.

Clinical implications

Dietary interventions with increased content in natural fibers like pectins would ameliorate asthma exacerbations. Moreover, respiratory infection in asthma downregulated SCFA in the gut contributing to asthma exacerbations.

Gut microbiome signature and nasal lavage inflammatory markers in young people with asthma

Background

Asthma is a complex disease and a severe global public health problem resulting from interactions between genetic background and environmental exposures. It has been suggested that gut microbiota may be related to asthma development; however, such relationships needs further investigation.

Objective

This study aimed to characterize the gut microbiota as well as the nasal lavage cytokine profile of asthmatic and nonasthmatic individuals.

Methods

Stool and nasal lavage samples were collected from 29 children and adolescents with type 2 asthma and 28 children without asthma in Brazil. Amplicon sequencing of the stool bacterial V4 region of the 16S rRNA gene was performed using Illumina MiSeq. Microbiota analysis was performed by QIIME 2 and PICRUSt2. Type 2 asthma phenotype was characterized by high sputum eosinophil counts and positive skin prick tests for house dust mite, cockroach, and/or cat or dog dander. The nasal immune marker profile was assessed using a customized multiplex panel.

Results

Stool microbiota differed significantly between asthmatic and nonasthmatic participants (P = .001). Bacteroides was more abundant in participants with asthma (P < .05), while Prevotella was more abundant in nonasthmatic individuals (P < .05). In people with asthma, the relative abundance of Bacteroides correlated with IL-4 concentration in nasal lavage samples. Inference of microbiota functional capacity identified differential fatty acid biosynthesis in asthmatic compared to nonasthmatic subjects.

Conclusion

The stool microbiota differed between asthmatic and nonasthmatic young people in Brazil. Asthma was associated with higher Bacteroides levels, which correlated with nasal IL-4 concentration.

Baseline Characteristics and ICS/LAMA/LABA Response in Asthma: Analyses From the CAPTAIN Study

BACKGROUND

Findings from CAPTAIN (NCT02924688) suggest that treatment response to fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) differs according to baseline type 2 inflammation markers in patients with moderate to severe asthma. Understanding how other patient physiologic and clinical characteristics affect response to inhaled therapies may guide physicians toward a personalized approach for asthma management.

OBJECTIVE

To investigate, using CAPTAIN data, the predictive value of key demographic and baseline physiologic variables in patients with asthma (lung function, bronchodilator reversibility, age, age at asthma onset) on response to addition of the long-acting muscarinic antagonist UMEC to inhaled corticosteroid/long-acting β2-agonist combination FF/VI, or doubling the FF dose.

METHODS

Prespecified and post hoc analyses of CAPTAIN data were performed using categorical and continuous variables of key baseline characteristics to understand their influence on treatment outcomes (lung function [trough FEV1], annualized rate of moderate/severe exacerbations, and asthma control [Asthma Control Questionnaire]) following addition of UMEC to FF/VI or doubling the FF dose in FF/VI or FF/UMEC/VI.

RESULTS

Adding UMEC to FF/VI led to greater improvements in trough FEV1 versus doubling the FF dose across all baseline characteristics assessed. Doubling the FF dose was generally associated with numerically greater reductions in the annualized rate of moderate/severe exacerbations compared with adding UMEC, independent of baseline characteristics. Adding UMEC and/or doubling the FF dose generally led to improvements in Asthma Control Questionnaire scores irrespective of baseline characteristics.

CONCLUSIONS

Unlike previous findings with type 2 biomarkers, lung function, bronchodilator reversibility, age and age at asthma onset do not appear to predict response to inhaled therapy.

Allergen skin test responses in broad U.S. asthma population in those with and without rhinitis

Background: Asthma and allergic rhinitis are pathologically interlinked conditions. Despite skin testing (ST) being pivotal for evaluating allergic sensitization, U.S. data that date back to 1960s on ST reactivity patterns in subjects with asthma remain sparse. Objective: The purpose of this study was to elucidate seasonal, perennial ST responses, and their relationship with asthma severity, early versus late onset disease, and immunoglobulin E (IgE) levels. Methods: Five hundred patients with asthma were randomly selected from the National Jewish Health electronic medical record over a 3-year span. Demographic, clinical, and allergen ST reactivity data for a battery of seasonal and perennial allergens were procured, including total IgE levels, asthma onset, and severity, by using t-tests, χ² tests, and Analysis of Variance (ANOVA), patterns of reactivity were assessed for overall, seasonal, and perennial allergens in relation to IgE levels, asthma onset, and severity. Results: Of the 500 patients, 398 were analyzed. 63.3% were women, 50.1% had adult-onset asthma, and 86.1% had rhinitis; 75.3% tested positive to one or more allergens, with men demonstrating higher overall (p = 0.039) and perennial (p = 0.035) sensitization. ST reactivity varied based on the presence of rhinitis for seasonal (p = 0.028) but not perennial (p = 0.733) allergens. Asthma severity was not significantly associated with ST reactivity (p > 0.10). ST positivity for perennial (p < 0.001) but not seasonal (p = 0.128) allergens was higher in childhood-onset asthma versus adult-onset asthma despite both groups having a large percentage of reactors. Elevated IgE levels correlated with ST reactivity (p < 0.01). Conclusion: Our study represents a unique comprehensive evaluation of ST reactivity in a U.S. asthma population, which is lacking in the literature, when factoring in asthma onset, severity, and IgE levels. Our findings underscore the importance of allergen sensitization in asthma, regardless of severity, concurrent rhinitis symptoms, or asthma onset, which challenge some of the prevailing assumptions about the relationship between allergen sensitization and asthma onset.

Association between allergic conditions and COVID-19 susceptibility and outcomes

BACKGROUND

The relationship between underlying type 2 inflammation and immune response to COVID-19 is unclear.

OBJECTIVE

To assess the relationships between allergic conditions and COVID-19 susceptibility and outcomes.

METHODS

In the Optum database, adult patients with and without major allergic conditions (asthma, atopic dermatitis [AD], allergic rhinitis, food allergy, anaphylaxis, or eosinophilic esophagitis) and patients with and without severe asthma/AD were identified. Adjusted incidence rate ratios for COVID-19 were compared among patients with vs without allergic conditions or severe asthma/AD vs non-severe asthma/AD during April 1, 2020, to December 31, 2020. Among patients with COVID-19, adjusted hazard ratios (aHRs) of 30-day COVID-19-related hospitalization/all-cause mortality were estimated for the same comparisons during April 1, 2020, to March 31, 2022.

RESULTS

Patients with (N = 1,273,231; asthma, 47.2%; AD, 1.5%; allergic rhinitis, 58.6%; food allergy, 5.1%; anaphylaxis, 4.1%; eosinophilic esophagitis, 0.9%) and without allergic conditions (N = 2,278,571) were identified. Allergic conditions (adjusted incidence rate ratios [95% CI], 1.22 [1.21-1.24]) and asthma severity (1.12 [1.09-1.15]) were associated with increased incidence of COVID-19. Among patients with COVID-19 (patients with [N = 261,076] and without allergic conditions [N = 1,098,135] were matched on age, sex, region, index month), having an allergic condition had minimal impact on 30-day COVID-19-related hospitalization/all-cause mortality (aHR [95% CI] 0.96 [0.95-0.98]) but was associated with a lower risk of mortality (0.80 [0.78-0.83]). Asthma was associated with a higher risk of COVID-19-related hospitalization/all-cause mortality vs non-asthma allergic conditions (aHR [95% CI], 1.27 [1.25-1.30]), mostly driven by higher hospitalization.

CONCLUSION

Allergic conditions were associated with an increased risk of receiving COVID-19 diagnosis but reduced mortality after infection.

Hydrangea serrata extract attenuates PM-exacerbated airway inflammation in the CARAS model by modulating the IL-33/ST2/NF-κB signaling pathway

Particulate matter (PM) significantly contributes to the global health crisis of respiratory diseases. It is known to induce and exacerbate conditions such as asthma and respiratory infections. Long exposure to PM can increase the risk of combined allergic rhinitis and asthma syndrome (CARAS). Although therapeutic drugs can be used to improve symptoms of respiratory diseases caused by PM, their usage is often accompanied by side effects. Therefore, many studies are being conducted to discover functional food materials that can more effectively treat respiratory diseases while minimizing the side effects of these therapeutic drugs. This study was conducted to investigate the efficacy of Hydrangea serrata extract (HSE) in airway inflammation in a mouse model of CARAS exacerbated by PM. In the CARAS mouse model worsened by PM, the airway inflammation improvement effect of HSE was evaluated by analyzing allergic nasal symptoms, changes in inflammatory cells, OVA-specific immunoglobulin (Ig) levels, cytokines, mast cell activation, and histopathological findings of both nasal mucosa and lung tissue. HSE effectively reduced OVA-specific IgE and IgG1 and inhibited the production of T helper type 2 (Th2)-related cytokines such as IL-4 and IL-5. Importantly, HSE reduced IL-33 and ST2 expression and inhibited the activation of the NF-κB signaling pathway. In addition, HSE inhibited airway hypersensitivity, mucus production, and inflammatory cell infiltration. These results suggest that HSE may inhibit airway inflammation in CARAS/PM mice by regulating the IL-33/ST2/NF-κB signaling pathway, opening avenues for considering HSE as a potential material for treating allergic airway inflammation diseases in the future.

A Roadmap for Using Causal Inference and Machine Learning to Personalize Asthma Medication Selection

Inhaled corticosteroid (ICS) is a mainstay treatment for controlling asthma and preventing exacerbations in patients with persistent asthma. Many types of ICS drugs are used, either alone or in combination with other controller medications. Despite the widespread use of ICSs, asthma control remains suboptimal in many people with asthma. Suboptimal control leads to recurrent exacerbations, causes frequent ER visits and inpatient stays, and is due to multiple factors. One such factor is the inappropriate ICS choice for the patient. While many interventions targeting other factors exist, less attention is given to inappropriate ICS choice. Asthma is a heterogeneous disease with variable underlying inflammations and biomarkers. Up to 50% of people with asthma exhibit some degree of resistance or insensitivity to certain ICSs due to genetic variations in ICS metabolizing enzymes, leading to variable responses to ICSs. Yet, ICS choice, especially in the primary care setting, is often not tailored to the patient's characteristics. Instead, ICS choice is largely by trial and error and often dictated by insurance reimbursement, organizational prescribing policies, or cost, leading to a one-size-fits-all approach with many patients not achieving optimal control. There is a pressing need for a decision support tool that can predict an effective ICS at the point of care and guide providers to select the ICS that will most likely and quickly ease patient symptoms and improve asthma control. To date, no such tool exists. Predicting which patient will respond well to which ICS is the first step toward developing such a tool. However, no study has predicted ICS response, forming a gap. While the biologic heterogeneity of asthma is vast, few, if any, biomarkers and genotypes can be used to systematically profile all patients with asthma and predict ICS response. As endotyping or genotyping all patients is infeasible, readily available electronic health record data collected during clinical care offer a low-cost, reliable, and more holistic way to profile all patients. In this paper, we point out the need for developing a decision support tool to guide ICS selection and the gap in fulfilling the need. Then we outline an approach to close this gap via creating a machine learning model and applying causal inference to predict a patient's ICS response in the next year based on the patient's characteristics. The model uses electronic health record data to characterize all patients and extract patterns that could mirror endotype or genotype. This paper supplies a roadmap for future research, with the eventual goal of shifting asthma care from one-size-fits-all to personalized care, improve outcomes, and save health care resources.

Exploring novel perspectives on eosinophilic inflammation in severe asthma

Two recent articles by the same research group documented that patients with severe eosinophilic asthma exhibit an increased proportion of a subtype of eosinophils, namely CD62Llow inflammatory eosinophils (iEos) and identified an intriguing correlation between such iEos and asthma control scores. Moreover, CD62Llow iEos were reduced after treatment with the anti-IL-5 monoclonal antibody mepolizumab. In the future, we believe that eosinophil subtypes could represent a useful biomarker in severe eosinophilic asthma, helping clinicians characterize patient endotypes and monitoring the response to biological drugs.

Bioinformatics analysis revealed underlying molecular mechanisms associated with asthma severity and identified GABAergic related pathway as a potential therapy for Th2-high endotype asthma

Background

Asthma, a principally T helper 2 (Th2) cell mediated immunological disease, is categorized into Th2-high and Th2-low endotypes. The influence of these endotypes on clinical characteristics and treatment responsiveness in asthma is yet to be completely understood. This study delves into the underlying molecular mechanisms of Th2 endotypes on asthma.

Methods

Transcriptomics data of airway epithelial and corresponding clinical information were sourced from the GEO. The co-expression modules were established by WGCNA. Cytoscape was applied to construct PPI networks, and hub genes were determined via the Cytohubba plugin. Additionally, a functional enrichment analysis was conducted on the co-expressed genes from the relevant modules. The relative abundances levels of 22 different types of immune cells in asthma patients were evaluated by CIBERSORT algorithm.

Results

There were 471 genes in the pink module significantly correlated with Th2 endotype. Overall, 151 DEGs were identified in the various Th2 endotypes, and 66 were obtained through intersection with the pink module. In the PPI network, the ten most important genes that regulate Th2 endotypes were selected as hub genes. In Th2-high endotype asthma, the hub genes were significantly related to γ-aminobutyric acid (GABA) pathways, indicating that hub genes can mainly regulate Th2-high endotype asthma through GABAergic system.

Conclusions

The severity of asthma is influenced by different Th2 endotypes. GABAergic related hub genes may provide innovative insights for the treatment of Th2-high asthma.