Advances in asthma: New understandings of asthma's natural history, risk factors, underlying mechanisms, and clinical management

Mechanistic and Therapeutic Approaches to Occupational Exposure-Associated Allergic and Non-Allergic Asthmatic Disease

PURPOSE OF REVIEW

Occupational lung disease, including asthma, is a significant cause of disability worldwide. The dose, exposure frequency, and nature of the causal agent influence the inflammatory pathomechanisms that inform asthma disease phenotype and progression. While surveillance, systems engineering, and exposure mitigation strategies are essential preventative considerations, no targeted medical therapies are currently available to ameliorate lung injury post-exposure and prevent chronic airway disease development.

RECENT FINDINGS

This article reviews contemporary understanding of allergic and non-allergic occupational asthma mechanisms. In addition, we discuss the available therapeutic options, patient-specific susceptibility and prevention measures, and recent scientific advances in post-exposure treatment conception. The course of occupational lung disease that follows exposure is informed by individual predisposition, immunobiologic response, agent identity, overall environmental risk, and preventative workplace practices. When protective strategies fail, knowledge of underlying disease mechanisms is necessary to inform targeted therapy development to lessen occupational asthma disease severity and occurrence.

Determinants of Childhood Asthma: A Case Control Study from a Tertiary Care Hospital in Bengaluru, South India

BACKGROUND

Childhood asthma is a common, and often serious, chronic disease with episodic exacerbations in infants and children. There is an increasing trend in the prevalence of childhood asthma in developing countries. Objectives: To identify the determinants of childhood asthma.

METHODS

A case control study with 30 cases of childhood asthma and 30 gender- and aged-matched controls selected from the paediatric outpatient department and paediatric ward of a tertiary hospital. The primary caregiver was interviewed to capture sociodemographic details, prenatal and birth history, and history of exposure to environmental risk factors. Odds ratios with 95% confidence intervals were calculated to determine the strength of association between childhood asthma and independent co-variates, followed by subgroup multiple logistic regression analysis.

RESULTS

We found that children with a parental history of allergy/atopy [OR=2.88 (1.94-4.27), P<0.001], residence in houses located in industrial areas [AOR=2.72 (2.6-323.1), P<0.001], exposure to incense at home [AOR=2.03 (1.14-29.42), P<0.001], or a history of allergic rhinitis [AOR=3.09 (2.22-243.25), P<0.001] had significantly higher odds of developing childhood asthma.

CONCLUSION

Our study found that having homes located in industrial areas, burning incense at home, parental history of allergy, and history of allergic rhinitis in the child are determinants of childhood asthma. The findings from our study can be used to generate awareness regarding risk factors that are linked to childhood asthma.

The clinical characteristics of patients with asthma exposed to different environmental risk factors: A cross-sectional study

BACKGROUND

Smoking, biomass, and occupational exposure are the main environmental risk factors for asthma. The purpose of this study was to analyze the clinical characteristics of exposure to these risk factors in patients with asthma.

METHODS

This cross-sectional study enrolled patients with asthma from an outpatient department according to the Global Initiative for Asthma. Demographics, forced expiratory volume in 1 s (FEV1), FEV1%pred, FEV1/forced vital capacity (FVC), laboratory tests, asthma control test (ACT), asthma control questionnaire (ACQ) scores, and the inhaled corticosteroid (ICS) dose were recorded. A generalized linear mixed model was used to adjust for potential confounders.

RESULTS

A total of 492 patients with asthma were included in this study. Of these patients, 13.0% were current smokers, 9.6% were former smokers, and 77.4% were never smokers. Compared with never smokers, the current and former smokers had a longer duration of asthma; lower ACT scores, FEV1, FEV1%pred, and FEV1/FVC; and higher ACQ scores, IgE, FeNO, blood eosinophils, and ICS dose (p < .05). In addition, the patients exposed to biomass alone were older; had higher exacerbation in the past year; a longer duration of asthma; and lower FEV1, FEV1%pred, FEV1/FVC, IgE, and FeNO compared with smoking or occupational exposure alone. Compared with smoking exposure alone, patients with occupational exposure alone had a longer duration of asthma and lower FEV1, FEV1%pred, FVC, IgE, FeNO, and ICS dose (p < .05).

CONCLUSIONS

There are significant differences in the clinical characteristics of patients with asthma depending on the smoking status. In addition, significant differences also observed among smoking, biomass, and occupational exposure.

Ablation of CD226 on CD4+ T cells modulates asthma progress associated with altered IL-10 response and gut microbiota

To investigate the role of the costimulatory molecule CD226 in asthma pathogenesis, we produced a CD4⁺ T-cell-specific CD226 knockout mice model (Cd226^ΔCD4) and induced airway allergic inflammation by administering ovalbumin (OVA). Our results revealed alleviated lung inflammation, decreased levels of OVA-specific IgE, and increased levels of IL-10 in the serum of Cd226^ΔCD4 mice (P < 0.05). Moreover, IL-10 levels in CD4⁺ T cells were significantly elevated in the mediastinal lymph node, spleen, and Peyer's patches in the Cd226^ΔCD4 mice compared with those in controls (P < 0.05 to P < 0.01). Notably, there was a significantly higher IL-10 mRNA levels in the large intestine of the mice (P < 0.05). The protective effect of CD226 deficiency is also associated with the accumulation of gut TCRγδ⁺ intraepithelial lymphocytes and reversion of the gut microbiome dysbiosis. The Bacteroidetes-to-Firmicutes ratio and the abundance of Akkermansia increased in the absence of CD226 after OVA treatment. Our data reveal the synchronous changes in the lung and intestine in OVA-treated CD226-knockout mice, supporting the gut-lung axis concept and providing evidence for novel therapeutic approaches for asthma.

Updates in diagnosis and management of paediatric mastocytosis

PURPOSE OF REVIEW

Paediatric mastocytosis is a rare clonal disorder characterized by the overproduction and organ infiltration of mast cells. Symptoms are due to mast cell mediator release. Cutaneous mastocytosis is the most common presentation in children with systemic disease being rare. Our aim is to provide a practical guideline in differentiating subtypes of paediatric mastocytosis while providing actionable recommendations on diagnosis, clinical management, follow-up and prognosis.

RECENT FINDINGS

Longitudinal cohort studies of paediatric cutaneous mastocytosis have shown spontaneous remission with favourable prognosis. Hereditary alpha-tryptasemia may coexist with mastocytosis; thus, screening for this disorder is recommended. There is an emerging role for serum tryptase in asthma endotyping and potential for using therapeutic tryptase inhibitors.

SUMMARY

Morbidity in paediatric mastocytosis typically arises from symptoms secondary to mast cell mediator release. Prognosis for nonaggressive disease is typically favourable; however, risks for anaphylaxis and psychosocial morbidity may be underestimated. Symptomatic management and anticipatory guidance may help support patients and families throughout the disease course.

Patient characteristics and eligibility for biologics in severe asthma: Results from the Greek cohort of the RECOGNISE "real world" study

BACKGROUND

Some patients with severe asthma do not achieve sufficient symptom control despite guideline-based treatment, and therefore receive oral (OCS) and systemic corticosteroids (SCS) on regular basis. The side effects of corticosteroid use negatively impact patients' health-related quality of life (HRQoL) and increase the disease burden. Biologics have shown promise in asthma therapy; however, identifying patients who might benefit from biologic therapy is complex due to the heterogeneous pathophysiology of the disease.

METHODS

The European, non-interventional, multicentre RECOGNISE study (NCT03629782) assessed patient characteristics, asthma medication and control, HRQoL as assessed by St. George's Respiratory Questionnaire (SGRQ), and health care resource use in patients with severe asthma, as well as their eligibility for biologic treatment. Here, data from the Greek cohort (N = 97) are reported.

RESULTS

In Greece, patients with severe asthma were more often female (71%) and never smokers (68%). 87% of patients were assessed as eligible for biologic treatment by investigator's judgement (per label criteria: 76%). Most patients had been previously treated with SCS (82% eligible vs 85% non-eligible), with OCS use being more common in non-eligible patients (23.1% vs 11.9%). More eligible patients had poorly controlled asthma (76% vs 54%), and more impaired HRQoL (mean total SGRQ score: 46% vs 39%); symptom burden was significantly higher (mean symptom score: 60% vs. 44%, p: 0.0389).

CONCLUSIONS

A high proportion of Greek patients with severe asthma are eligible for biologic therapy; however, individual risk factors and differences between asthma types must be considered before the introduction of targeted therapy.

Special Issue on ‘Asthma and Allergic Inflammation’

Asthma is a chronic inflammatory airway disease, driven by either allergic or non-allergic stimuli, which usually manifests as wheezing, reversible airflow limitation, and bronchial hyperresponsiveness [...]

lncRNA CRNDE Affects Th17/IL-17A and Inhibits Epithelial-Mesenchymal Transition in Lung Epithelial Cells Reducing Asthma Signs

Background

Asthma treatment is difficult due to disease heterogeneity and comorbidities. In addition, the development of drugs targeting the underlying mechanisms of asthma remains slow. We planned to identify the most upregulated differentially expressed long noncoding RNA in asthma to explore its regulatory patterns and pathways in asthma.

Methods

We sensitized mice using a mixture of ovalbumin, house dust mites, and lipopolysaccharide to establish an asthma mouse model. We also sensitized asthma cells with TGF-β1 in an in vitro model. We performed a microarray analysis to identify the lncRNA with the differential expression level in model mice. We applied hematoxylin and eosin and Masson's trichrome stainings to mouse tissues to quantify the tissue damage extent. Next, we assess the levels of lncRNA CRNDE, miR-29a-3p, TGF-β1, MCL-1, E-cadherin, vimentin, and snail. We counted the percentages of Th17 cells using flow cytometry. Finally, we performed a dual-luciferase reporter assay to assess the association between lncRNA CRNDE and miR-29a-3p.

Results

We successfully established asthma mouse/cell models and selected the lncRNA CRNDE for our study. Transfection of si-CRNDE reduced the degree of injury and inflammation in the mouse model and reversed the TGF-β1-induced epithelial-mesenchymal transition (EMT) in the cell model. Moreover, the E-cadherin level was upregulated, and the levels of IL-17A, vimentin, snail, and α-SMA were downregulated. We also discovered that lncRNA CRNDE negatively regulated miR-29a-3p and that this one in turn inhibited MCL-1 in mice. After lncRNA CRNDE expression downregulation, the level of miR-29a-3p was increased, and we detected reduced levels of MCL-1 and EMTs.

Conclusions

lncRNA CRNDE expression downregulation led to reduced inflammation and reduced lung damage in mice with induced asthma, it inhibited the EMTs of lung epithelial cells via the miR-29a-3p/MCL-1 pathway, and it reduced the levels of Th17/IL-17A cells to reduce asthma signs.

MiR-185-5p measurement assists in reflecting Th1/Th2 cell imbalance, inflammatory cytokine production, and exacerbation risk for childhood asthma

BACKGROUND

MicroRNA (miR)-185-5p participates in the pathology of asthma by regulating immune imbalance, inflammation, periostin synthesis, and smooth muscle contraction. This study intended to explore the dysregulation of miR-185p and its correlation with T-helper (Th)1, Th2 cells, and inflammatory cytokines in childhood asthma.

METHODS

In 150 childhood asthma patients and 30 healthy controls (HCs), miR-185-5p from peripheral blood mononuclear cells was detected using reverse transcription-quantitative polymerase chain reaction, Th cells from peripheral blood samples were detected using flow cytometry, inflammatory cytokines from serum samples were detected using enzyme-linked immunosorbent assay.

RESULTS

MiR-185-5p was increased in childhood asthma patients versus HCs [median (interquartile range (IQR)): 2.315 (1.770-3.855) versus 1.005 (0.655-1.520)] (P < 0.001). Meanwhile, miR-185-5p was negatively associated with Th1 cells (P = 0.035) but positively correlated with Th2 cells (P = 0.006) and IL-4 (P = 0.003) in childhood asthma patients; however, miR-185-5p was not linked to Th1 cells, Th2 cells, IFN-γ, or IL-4 in HCs (all P > 0.05). In addition, miR-185-5p was positively related to TNF-α (P < 0.001), IL-1β (P = 0.015), and IL-6 (P = 0.008) in childhood asthma patients, miR-185-5p was only linked to TNF-α (P = 0.040) but not IL-1β or IL-6 (both P > 0.05) in HCs. Moreover, miR-185-5p was increased in exacerbated childhood asthma patients versus remissive patients [median (IQR): 3.170 (2.070-4.905) versus 1.900 (1.525-2.615)] (P < 0.001). Besides, miR-185-5p was highest in patients with severe exacerbation followed by patients with moderate exacerbation, and lowest in patients with mild exacerbation (P = 0.010).

CONCLUSION

MiR-185-5p is associated with imbalanced Th1/Th2 cells, increased inflammatory cytokines along with elevated exacerbation risk, and severity in childhood asthma patients.

Sterols and immune mechanisms in asthma

The field of sterol and oxysterol biology in lung disease has recently gained attention, revealing a unique need for sterol uptake and metabolism in the lung. The presence of cholesterol transport, biosynthesis, and sterol/oxysterol-mediated signaling in immune cells suggests a role in immune regulation. In support of this idea, statin drugs that inhibit the cholesterol biosynthesis rate-limiting step enzyme, hydroxymethyl glutaryl coenzyme A reductase, show immunomodulatory activity in several models of inflammation. Studies in human asthma reveal contradicting results, whereas promising retrospective studies suggest benefits of statins in severe asthma. Here, we provide a timely review by discussing the role of sterols in immune responses in asthma, analytical tools to evaluate the role of sterols in disease, and potential mechanistic pathways and targets relevant to asthma. Our review reveals the importance of sterols in immune processes and highlights the need for further research to solve critical gaps in the field.

Skin Barrier Function and Infant Tidal Flow-Volume Loops-A Population-Based Observational Study

Background: The relationship between the skin barrier- and lung function in infancy is largely unexplored. We aimed to explore if reduced skin barrier function by high transepidermal water loss (TEWL), or manifestations of eczema or Filaggrin (FLG) mutations, were associated with lower lung function in three-month-old infants. Methods: From the population-based PreventADALL cohort, 899 infants with lung function measurements and information on either TEWL, eczema at three months of age and/or FLG mutations were included. Lower lung function by tidal flow-volume loops was defined as a ratio of time to peak tidal expiratory flow to expiratory time (tPTEF/tE) <0.25 and a tPTEF <0.17 s (<25th percentile). A high TEWL >8.83 g/m2/h (>75th percentile) denoted reduced skin barrier function, and DNA was genotyped for FLG mutations (R501X, 2282del4 and R2447X). Results: Neither a high TEWL, nor eczema or FLG mutations, were associated with a lower tPTEF/tE. While a high TEWL was associated with a lower tPTEF; adjusted OR (95% CI) 1.61 (1.08, 2.42), the presence of eczema or FLG mutations were not. Conclusions: Overall, a high TEWL, eczema or FLG mutations were not associated with lower lung function in healthy three-month-old infants. However, an inverse association between high TEWL and tPTEF was observed, indicating a possible link between the skin barrier- and lung function in early infancy.

Asparagus cochinchinensis: A review of its botany, traditional uses, phytochemistry, pharmacology, and applications

Asparagus cochinchinensis (Lour.) Merr. (A. cochinchinensis) is a traditional herbal medicine that is used to treat constipation, fever, pneumonia, stomachache, tracheitis, rhinitis, cataract, acne, urticaria. More than 90 compounds have been identified from different structural types in A. cochinchinensis, including steroidal saponins, C21-steroides, lignans, polysaccharides, amino acids, etc. These bioactive ingredients make A. cochinchinensis remarkable for its pharmacological effects on anti-asthma, anti-inflammatory, anti-oxidation, anti-tumor, improving Alzheimer’s disease, neuroprotection, gut health-promoting and so on. Moreover, A. cochinchinensis also plays an important role in food, health product, cosmetic, and other fields. This review focused on the research publications of A. cochinchinensis and aimed to summarize the advances in the botany, traditional uses, phytochemistry, pharmacology, and applications which will provide reference for the further studies and applications of A. cochinchinensis.

Dexmedetomidine attenuates airway inflammation and oxidative stress in asthma via the Nrf2 signaling pathway

Allergic asthma is a chronic inflammatory disease in which oxidative stress serves a pivotal role. In clinical practice, dexmedetomidine (DEX), an α‑2‑adrenergic receptor agonist, is used as a sedative. DEX exhibits antioxidative and organ‑protective properties. In a murine model of asthma, DEX has a therapeutic effect via the toll like receptor 4/NF‑кB signaling pathway; however, whether DEX can exert an antioxidative effect on asthma has yet to be elucidated. In the present study, a T helper (Th)2‑dominant murine asthma model was established. DEX treatment significantly reduced eosinophilic airway inflammation, mucus overproduction and airway hyperresponsiveness, as well as the concentrations of Th2 cytokines. The lung tissues of mice with asthma were characterized by redox imbalance (increased oxidative stress and impaired antioxidant capacity). DEX treatment alleviated this imbalance by decreasing the levels of malondialdehyde and reactive oxygen species, and increasing the levels of glutathione. Furthermore, the nuclear factor erythroid 2‑related factor 2 (Nrf2) signaling pathway was inhibited in the lung tissues of asthmatic mice; these effects were noted in its downstream genes, heme oxygenase 1 and glutathione peroxidase 4. In mice with asthma, DEX treatment induced the expression of these antioxidant genes and the activation of Nrf2, whereas ML385 (an inhibitor of Nrf2) partially abrogated the antioxidative and therapeutic effects of DEX. To the best of our knowledge, the present study is the first to demonstrate the protective effect of DEX on Th2‑dominant asthma through the activation of the Nrf2 signaling pathway. The results suggested that the antioxidative properties of DEX could be beneficial in clinical application of DEX for the relief of asthmatic symptoms.

Microbial dysbiosis and childhood asthma development: Integrated role of the airway and gut microbiome, environmental exposures, and host metabolic and immune response

Asthma is a chronic and heterogeneous respiratory disease with many risk factors that typically originate during early childhood. A complex interplay between environmental factors and genetic predisposition is considered to shape the lung and gut microbiome in early life. The growing literature has identified that changes in the relative abundance of microbes (microbial dysbiosis) and reduced microbial diversity, as triggers of the airway-gut axis crosstalk dysregulation, are associated with asthma development. There are several mechanisms underlying microbial dysbiosis to childhood asthma development pathways. For example, a bacterial infection in the airway of infants can lead to the activation and/or dysregulation of inflammatory pathways that contribute to bronchoconstriction and bronchial hyperresponsiveness. In addition, gut microbial dysbiosis in infancy can affect immune development and differentiation, resulting in a suboptimal balance between innate and adaptive immunity. This evolving dysregulation of secretion of pro-inflammatory mediators has been associated with persistent airway inflammation and subsequent asthma development. In this review, we examine current evidence around associations between the airway and gut microbial dysbiosis with childhood asthma development. More specifically, this review focuses on discussing the integrated roles of environmental exposures, host metabolic and immune responses, airway and gut microbial dysbiosis in driving childhood asthma development.

A Methylation Diagnostic Model Based on Random Forests and Neural Networks for Asthma Identification

Background

Asthma significantly impacts human life and health as a chronic disease. Traditional treatments for asthma have several limitations. Artificial intelligence aids in cancer treatment and may also accelerate our understanding of asthma mechanisms. We aimed to develop a new clinical diagnosis model for asthma using artificial neural networks (ANN).

Methods

Datasets (GSE85566, GSE40576, and GSE13716) were downloaded from Gene Expression Omnibus (GEO) and identified differentially expressed CpGs (DECs) enriched by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Random forest (RF) and ANN algorithms further identified gene characteristics and built clinical models. In addition, two external validation datasets (GSE40576 and GSE137716) were used to validate the diagnostic ability of the model.

Results

The methylation analysis tool (ChAMP) considered DECs that were up-regulated (n =121) and down-regulated (n =20). GO results showed enrichment of actin cytoskeleton organization and cell-substrate adhesion, shigellosis, and serotonergic synapses. RF (random forest) analysis identified 10 crucial DECs (cg05075579, cg20434422, cg03907390, cg00712106, cg05696969, cg22862094, cg11733958, cg00328720, and cg13570822). ANN constructed the clinical model according to 10 DECs. In two external validation datasets (GSE40576 and GSE137716), the Area Under Curve (AUC) for GSE137716 was 1.000, and AUC for GSE40576 was 0.950, confirming the reliability of the model.

Conclusion

Our findings provide new methylation markers and clinical diagnostic models for asthma diagnosis and treatment.

The causal relationship between allergic diseases and heart failure: Evidence from Mendelian randomization study

Background

Emerging evidence shows allergic diseases, such as atopic dermatitis and asthma, are risk factors of heart failure. However, the causal relationship between allergic diseases and heart failure is not clear.

Methods

We performed a two-sample Mendelian randomization analysis between allergic diseases and heart failure using summary statistics of genome-wide association studies from large GWAS consortia, with total sample size of 1.2 million. Independent instrumental variables for asthma and atopic dermatitis (P<1×10−5) were used as the exposure. We applied five models for the Mendelian randomization analysis. Finally, we performed the sensitivity analyses to assess the robustness of the results.

Results

We have identified 55 independent single nucleotide polymorphisms (SNPs) for asthma 54 independent SNPs for atopic dermatitis as our instrumental variables. The inverse variance-weighted (IVW) analysis showed asthma was significantly associated with increased risk of heart failure (ORIVW = 1.04, 95% CI, 1.01–1.07, P = 0.03). The Mendelian randomization analysis using the other four models also showed consistent results with the IVW analysis. Similarly, atopic dermatitis was also significantly associated with an increased risk of heart failure (ORIVW = 1.03, 95% CI, 1.01–1.06, P = 0.01), consistent with the other four models. The sensitivity analysis showed no evidence of horizontal pleiotropy or results were driven by single SNPs.

Conclusion

Our study identified asthma and atopic dermatitis as a causal risk factor for heart failure and suggest inflammatory pathogenesis as a key factor contributing to the underlying mechanism. These findings emphasize the importance of asthma and allergy control in the prevention and management of heart failure.

Neobavaisoflavone inhibits allergic inflammatory responses by suppressing mast cell activation

Neobavaisoflavone (NBIF), a monomolecular compound extracted from Psoralea corylifolia (Leguminosae), is commonly used in traditional Chinese medicine for multiple purposes. NBIF is known to exert anti-fungal and anti-tumor effects, and promote bone formation. Whether NBIF exhibits anti-allergic effects by regulating mast cell activation remains unclear. Therefore, we designed this study to investigate the anti-allergic effects of NBIF on IgE/Ag-induced mouse bone marrow-derived mast cells and ovalbumin-induced asthma, and the passive systemic anaphylaxis (PSA) reaction in mice. Our results showed that NBIF suppresses the production of leukotriene C4, prostaglandin D2 and inflammatory cytokines, and decreases the degranulation of BMMCs stimulated by IgE/Ag. A thorough investigation ascertained that NBIF suppresses the phosphorylation of mitogen-activated protein kinases, and represses the nuclear factor-κB-related signaling pathway. In addition, the oral administration of NBIF in mice inhibited the IgE-induced PSA reaction in a dose-dependent manner. Overall, we provide new insights into how NBIF regulates the IgE/Ag-mediated signaling pathways. Moreover, our investigation promotes the potential use of NBIF in treating allergy and asthma.

Integrative genetics-metabolomics analysis of infant bronchiolitis-childhood asthma link: A multicenter prospective study

Background

Infants with bronchiolitis are at high risk for developing childhood asthma. While genome-wide association studies suggest common genetic susceptibilities between these conditions, the mechanisms underlying the link remain unclear.

Objective

Through integrated genetics-metabolomics analysis in this high-risk population, we sought to identify genetically driven metabolites associated with asthma development and genetic loci associated with both these metabolites and asthma susceptibility.

Methods

In a multicenter prospective cohort study of infants hospitalized for bronchiolitis, we profiled the nasopharyngeal metabolome and genotyped the whole genome at hospitalization. We identified asthma-related metabolites from 283 measured compounds and conducted metabolite quantitative trait loci (mtQTL) analyses. We further examined the mtQTL associations by testing shared genetic loci for metabolites and asthma using colocalization analysis and the concordance between the loci and known asthma-susceptibility genes.

Results

In 744 infants hospitalized with bronchiolitis, 28 metabolites (e.g., docosapentaenoate [DPA], 1,2-dioleoyl-sn-glycero-3-phosphoglycerol, sphingomyelin) were associated with asthma risk. A total of 349 loci were associated with these metabolites-161 for non-Hispanic white, 120 for non-Hispanic black, and 68 for Hispanics. Of these, there was evidence for 30 shared loci between 16 metabolites and asthma risk (colocalization posterior probability ≥0.5). The significant SNPs within loci were aligned with known asthma-susceptibility genes (e.g., ADORA1, MUC16).

Conclusion

The integrated genetics-metabolomics analysis identified genetically driven metabolites during infancy that are associated with asthma development and genetic loci associated with both these metabolites and asthma susceptibility. Identifying these metabolites and genetic loci should advance research into the functional mechanisms of the infant bronchiolitis-childhood asthma link.

Visualizing the knowledge domains and research trends of childhood asthma: A scientometric analysis with CiteSpace

BACKGROUND

Asthma is one of the most common chronic diseases in children globally. In recent decades, advances have been made in understanding the mechanism, diagnosis, treatment and management for childhood asthma, but few studies have explored its knowledge structure and future interests comprehensively.

OBJECTIVE

This scientometric study aims to understand the research status and emerging trends of childhood asthma.

METHODS

CiteSpace (version 5.8.R3) was used to demonstrate national and institutional collaborations in childhood asthma, analyze research subjects and journal distribution, review research keywords and their clusters, as well as detect research bursts.

RESULTS

A total of 14,340 publications related to childhood asthma were extracted from Web of Science (core database) during January 2011 to December 2021. The results showed that academic activities of childhood asthma had increased steadily in the last decade. Most of the research was conducted by developed countries while China, as a developing country, was also actively engaged in this field. In addition to subjects of allergy and immunology, both public health aspects and ecological environmental impacts on the disease were emphasized recently in this research field. Keywords clustering analysis indicated that research on asthma management and atopy was constantly updated and became the two major research focuses recently, as a significant shift in research hotspots from etiology and diagnosis to atopic march and asthma management was identified. Subgroup analysis for childhood asthma management and atopy suggested that caregiver- or physician-based education and interventions were emerging directions for asthma management, and that asthma should be carefully studied in the context of atopy, together with other allergic diseases.

CONCLUSIONS

This study presented a comprehensive and systematic overview of the research status of childhood asthma, provided clues to future research directions, and highlighted two significant research trends of asthma management and atopy in this field.

Advances in clinical outcomes: what we have learned during the COVID-19 pandemic

Our understanding of risk factors and interventions influencing outcomes from coronavirus disease 2019 (COVID-19) has continued to evolve, revealing advances emerging from hypotheses formed at the start of the pandemic. Epidemiologic studies have shown that asthma control, rather than a diagnosis of asthma, is a determinant of COVID-19 severity. Clinical outcomes in patients with primary immunodeficiencies, even in those with impaired cellular immunity, are variable. IL-6 has emerged as a reliable biomarker of COVID-19 severity, and large clinical trials have shown the potential for improving outcomes through inhibition of IL-6 signaling in some patients. Studies of genetic risk factors for severe COVID-19 have also revealed the importance of interferon homeostasis in the defense against severe acute respiratory syndrome coronavirus 2. Because COVID-19 vaccines constitute the primary tool for ending this pandemic, strategies have been developed to address potential allergic and immune-mediated reactions. Here, we discuss advances in our understanding of COVID-19 risk factors and outcomes within the context of allergic and immunologic mechanisms.