Neutrophilic asthma: a distinct target for treatment?

Lung CD4+ resident memory T cells use airway secretory cells to stimulate and regulate onset of allergic airway neutrophilic disease

Neutrophilic asthma is a vexing disease, but mechanistic and therapeutic advancements will require better models of allergy-induced airway neutrophilia. Here, we find that periodic ovalbumin (OVA) inhalation in sensitized mice elicits rapid allergic airway inflammation and pathophysiology mimicking neutrophilic asthma. OVA-experienced murine lungs harbor diverse clusters of CD4+ resident memory T (TRM) cells, including unconventional RORγtnegative/low T helper 17 (TH17) cells. Acute OVA challenge instigates interleukin (IL)-17A secretion from these TRM cells, driving CXCL5 production from Muc5achigh airway secretory cells, leading to destructive airway neutrophilia. The TRM and epithelial cell signals discovered herein are also observed in adult human asthmatic airways. Epithelial antigen presentation regulates this biology by skewing TRM cells toward TH2 and TH1 fates so that TH1-related interferon (IFN)-γ suppresses IL-17A-driven, CXCL5-mediated airway neutrophilia. Concordantly, in vivo IFN-γ supplementation improves disease outcomes. Thus, using our model of neutrophilic asthma, we identify lung epithelial-CD4+ TRM cell crosstalk as a key rheostat of allergic airway neutrophilia.

Integrative analysis of network pharmacology and proteomics reveal the protective effect of Xiaoqinglong Decotion on neutrophilic asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoqinglong Decotion (XQLD) is a commonly used Chinese herbal formula in clinical practice, especially for allergic diseases such as asthma. However, its intrinsic mechanism for the treatment of neutrophilic asthma (NA) remains unclear.

AIM OF THE STUDY

The aim of this study was to evaluate the efficacy and potential mechanisms of XQLD on NA using network pharmacology and in vivo experiments.

MATERIALS AND METHODS

First, the active compounds, potential targets and mechanisms of XQLD against NA were initially elucidated by network pharmacology. Then, OVA/CFA-induced NA mice were treated with XQLD to assess its efficacy. Proteins were then analyzed and quantified using a Tandem Mass Tags approach for differentially expressed proteins (DEPs) to further reveal the mechanisms of NA treatment by XQLD. Finally, the hub genes, critical DEPs and potential pathways were validated.

RESULTS

176 active compounds and 180 targets against NA were identified in XQLD. Protein-protein interaction (PPI) network revealed CXCL10, CX3CR1, TLR7, NCF1 and FABP4 as hub genes. In vivo experiments showed that XQLD attenuated inflammatory infiltrates, airway mucus secretion and remodeling in the lungs of NA mice. Moreover, XQLD significantly alleviated airway neutrophil inflammation in NA mice by decreasing the expression of IL-8, MPO and NE. XQLD also reduced the levels of CXCL10, CX3CR1, TLR7, NCF1 and FABP4, which are closely associated with neutrophil inflammation. Proteomics analysis identified 28 overlapping DEPs in the control, NA and XQLD groups, and we found that XQLD inhibited ferroptosis signal pathway (elevated GPX4 and decreased ASCL3) as well as the expression of ARG1, MMP12 and SPP1, while activating the Rap1 signaling pathway.

CONCLUSION

This study revealed that inhibition of ARG1, MMP12 and SPP1 expression as well as ferroptosis pathways, and activation of the Rap1 signaling pathway contribute to the therapeutic effect of XQLD on NA.

The role of extracellular traps released by neutrophils, eosinophils, and macrophages in asthma

Extracellular traps (ETs) are a specialized form of innate immune defense in which leukocytes release ETs composed of chromatin and active proteins to eliminate pathogenic microorganisms. In addition to the anti-infection effect of ETs, researchers have also discovered their involvement in the pathogenesis of inflammatory disease, tumors, autoimmune disease, and allergic disease. Asthma is a chronic airway inflammatory disease involving multiple immune cells. The increased level of ETs in asthma patients suggests that ETs play an important role in the pathogenesis of asthma. Here we review the research work on the formation mechanism, roles, and therapeutic strategies of ETs released by neutrophils, eosinophils, and macrophages in asthma.

Association of Obesity and Severe Asthma in Adults

The incidence of obesity and asthma continues to enhance, significantly impacting global public health. Adipose tissue is an organ that secretes hormones and cytokines, causes meta-inflammation, and contributes to the intensification of bronchial hyperreactivity, oxidative stress, and consequently affects the different phenotypes of asthma in obese people. As body weight increases, the risk of severe asthma increases, as well as more frequent exacerbations requiring the use of glucocorticoids and hospitalization, which consequently leads to a deterioration of the quality of life. This review discusses the relationship between obesity and severe asthma, the underlying molecular mechanisms, changes in respiratory function tests in obese people, its impact on the occurrence of comorbidities, and consequently, a different response to conventional asthma treatment. The article also reviews research on possible future therapies for severe asthma. The manuscript is a narrative review of clinical trials in severe asthma and comorbid obesity. The articles were found in the PubMed database using the keywords asthma and obesity. Studies on severe asthma were then selected for inclusion in the article. The sections: 'The classification connected with asthma and obesity', 'Obesity-related changes in pulmonary functional tests', and 'Obesity and inflammation', include studies on subjects without asthma or non-severe asthma, which, according to the authors, familiarize the reader with the pathophysiology of obesity-related asthma.

DEL-1, as an anti-neutrophil transepithelial migration molecule, inhibits airway neutrophilic inflammation in asthma

BACKGROUND

Neutrophil migration into the airways is a key process in neutrophilic asthma. Developmental endothelial locus-1 (DEL-1), an extracellular matrix protein, is a neutrophil adhesion inhibitor that attenuates neutrophilic inflammation.

METHODS

Levels of DEL-1 were measured in exhaled breath condensate (EBC) and serum in asthma patients by ELISA. DEL-1 modulation of neutrophil adhesion and transepithelial migration was examined in a co-culture model in vitro. The effects of DEL-1-adenoviral vector-mediated overexpression on ovalbumin/lipopolysaccharide (OVA/LPS)-induced neutrophilic asthma were studied in mice in vivo.

RESULTS

DEL-1 was primarily expressed in human bronchial epithelial cells and was decreased in asthma patients. Serum DEL-1 concentrations were reduced in patients with severe asthma compared with normal subjects (567.1 ± 75.3 vs. 276.8 ± 29.36 pg/mL, p < .001) and were negatively correlated to blood neutrophils (r = -0.2881, p = .0384) and neutrophil-to-lymphocyte ratio (NLR) (r = -0.5469, p < .0001). DEL-1 concentrations in the EBC of severe asthmatic patients (113.2 ± 8.09 pg/mL) were also lower than normal subjects (193.0 ± 7.61 pg/mL, p < .001) and were positively correlated with the asthma control test (ACT) score (r = 0.3678, p = .0035) and negatively related to EBC IL-17 (r = -0.3756, p = .0131), myeloperoxidase (MPO) (r = -0.5967, p = .0055), and neutrophil elastase (NE) (r = -0.5488, p = .0009) expression in asthma patients. Neutrophil adhesion and transepithelial migration in asthma patients were associated with LFA-1 binding to ICAM-1 and inhibited by DEL-1. DEL-1 mRNA and protein expression in human bronchial epithelial cells were regulated by IL-17. Exogenous DEL-1 inhibited IL-17-enhanced neutrophil adhesion and migration. DEL-1 expression was decreased while neutrophil infiltration was increased in the airway of a murine model of neutrophilic asthma. This was prevented by DEL-1 overexpression.

CONCLUSIONS

DEL-1 down-regulation leads to increased neutrophil migration across bronchial epithelial cells and is associated with neutrophilic airway inflammation in asthma.

T2-Low Asthma: A Discussed but Still Orphan Disease

Asthma affects 10% of the worldwide population; about 5% of cases are severe with the need for target therapies such as biologics. All the biologics approved for asthma hit the T2 pathway of inflammation. T2-high asthma is classified as allergic and non-allergic, whereas T2-low asthma can be further defined as paucigranulocytic asthma, Type 1 and Type-17 inflammation and the neutrophilic form that accounts for 20-30% of all patients with asthma. Neutrophilic asthma's prevalence is even higher in patients with severe or refractory asthma. We searched Medline and PubMed archives from the past ten years for articles with the subsequent titles: "neutrophilic asthma", "non-type 2 asthma" and "paucigranulocytic asthma". We identified 177 articles; 49 were considered relevant by the title and 33 by the reading of the abstract. Most of these articles are reviews (n = 19); only 6 are clinical trials. No study identified an effective treatment. We used the literature reported by these articles to search for further biologic treatments that target pathways different from T2. We identified 177 articles, 93 of which were considered relevant for the review and included in the present article. In conclusion, T2-low asthma remains poorly investigated in terms of biomarkers, especially as a therapeutic orphan disease.

Neutrophil extracellular traps in chronic lung disease: implications for pathogenesis and therapy

Neutrophilic inflammation has a key role in the pathophysiology of multiple chronic lung diseases. The formation of neutrophil extracellular traps (NETs) has emerged as a key mechanism of disease in neutrophilic lung diseases including asthma, COPD, cystic fibrosis and, most recently, bronchiectasis. NETs are large, web-like structures composed of DNA and anti-microbial proteins that are able to bind pathogens, prevent microbial dissemination and degrade bacterial virulence factors. The release of excess concentrations of proteases, antimicrobial proteins, DNA and histones, however, also leads to tissue damage, impaired mucociliary clearance, impaired bacterial killing and increased inflammation. A number of studies have linked airway NET formation with greater disease severity, increased exacerbations and overall worse disease outcomes across the spectrum of airway diseases. Treating neutrophilic inflammation has been challenging in chronic lung disease because of the delicate balance between reducing inflammation and increasing the risk of infections through immunosuppression. Novel approaches to suppressing NET formation or the associated inflammation are in development and represent an important therapeutic target. This review will discuss the relationship between NETs and the pathophysiology of cystic fibrosis, asthma, COPD and bronchiectasis, and explore the current and future development of NET-targeting therapies.

NETs contribute to the pathophysiology of chronic lung disease. Immunomodulating therapies that may reduce inflammatory mediators and NET formation, without compromising bacterial clearance, offer a new treatment path for patients. https://bit.ly/3fyJC6I

Hyperactive neutrophils infiltrate vital organs of tumor bearing host and contribute to gradual systemic deterioration via upregulated NE, MPO and MMP-9 activity

Cancer is known to have systemic impact by targeting various organs that ultimately compromises the overall physiology of the host. Several reports have demonstrated the role of neutrophils in cancer wherein the focus has been drawn on the elevated neutrophil count in blood or at tumor loci. However, their role in mediating systemic effects during cancer progression has not been deciphered so far. Therefore, it is worthwhile to explore whether and how neutrophils contribute to systemic deterioration in cancer. To discern their systemic role, we evaluated neutrophil count and function at different stages of tumor growth in Dalton's Lymphoma mice model. Notably, our results displayed a gradual increase in Ly6G⁺ neutrophils in peripheral blood and their infiltration in vital organs including liver, lungs, spleen, kidney, lymph nodes and peritoneum of tumor bearing host. We showed remarkable alterations in histoarchitecture and serum enzyme levels that aggravated with tumor progression. We next examined neutrophil function by assessing its granular cargoes including neutrophil elastase (NE), myeloperoxidase (MPO), and matrix metalloproteinases (MMP-8 and MMP-9). Interestingly, blood neutrophils of tumor bearing mice exhibited a marked change in morphology with gradual increase in NE and MPO expression with tumor growth. In addition, we observed upregulated expression of NE, MPO, MMP-8 and MMP-9 in the vital organs of tumor bearing host. Taken together, our results demonstrate heightened infiltration and function of neutrophils in vital organs of tumor bearing host which possibly account for gradual systemic deterioration during cancer progression. Our findings thus implicate neutrophils as a potential therapeutic target that may help to reduce the overall fatality rate of cancer.

Innate-like Lymphocytes and Innate Lymphoid Cells in Asthma

Asthma is a chronic pulmonary disease, highly associated with immune disorders. The typical symptoms of asthma include airway hyperresponsiveness (AHR), airway remodeling, mucus overproduction, and airflow limitation. The etiology of asthma is multifactorial and affected by genetic and environmental factors. Increasing trends toward dysbiosis, smoking, stress, air pollution, and a western lifestyle may account for the increasing incidence of asthma. Based on the presence or absence of eosinophilic inflammation, asthma is mainly divided into T helper 2 (Th2) and non-Th2 asthma. Th2 asthma is mediated by allergen-specific Th2 cells, and eosinophils activated by Th2 cells via the secretion of interleukin (IL)-4, IL-5, and IL-13. Different from Th2 asthma, non-Th2 asthma shows little eosinophilic inflammation, resists to corticosteroid treatment, and occurs mainly in severe asthmatic patients. Previous studies of asthma primarily focused on the function of Th2 cells, but, with the discovery of non-Th2 asthma and the involvement of innate lymphoid cells (ILCs) in the pathogenesis of asthma, tissue-resident innate immune cells in the lung have become the focus of attention in asthma research. Currently, innate-like lymphocytes (ILLs) and ILCs as important components of the innate immune system in mucosal tissues are reportedly involved in the pathogenesis of or protection against both Th2 and non-Th2 asthma. These findings of the functions of different subsets of ILLs and ILCs may provide clues for the treatment of asthma.

Scavenger Receptor BI Attenuates IL-17A-Dependent Neutrophilic Inflammation in Asthma

Asthma is a common respiratory disease currently affecting more than 300 million worldwide and is characterized by airway inflammation, hyperreactivity, and remodeling. It is a heterogeneous disease consisting of corticosteroid-sensitive T-helper cell type 2-driven eosinophilic and corticosteroid-resistant, T-helper cell type 17-driven neutrophilic phenotypes. One pathway recently described to regulate asthma pathogenesis is cholesterol trafficking. Scavenger receptors, in particular SR-BI (scavenger receptor class B type I), are known to direct cellular cholesterol uptake and efflux. We recently defined SR-BI functions in pulmonary host defense; however, the function of SR-BI in asthma pathogenesis is unknown. To elucidate the role of SR-BI in allergic asthma, SR-BI-sufficient (SR-BI+/+) and SR-BI-deficient (SR-BI-/-) mice were sensitized (Days 0 and 7) and then challenged (Days 14, 15, and 16) with a house dust mite (HDM) preparation administered through oropharyngeal aspiration. Airway inflammation and cytokine production were quantified on Day 17. When compared with SR-BI+/+ mice, the HDM-challenged SR-BI-/- mice had increased neutrophils and pulmonary IL-17A production in BAL fluid. This augmented IL-17A production in SR-BI-/- mice originated from a non-T-cell source that included neutrophils and alveolar macrophages. Given that SR-BI regulates adrenal steroid hormone production, we tested whether the changes in SR-BI-/- mice were glucocorticoid dependent. Indeed, SR-BI-/- mice were adrenally insufficient during the HDM challenge, and corticosterone replacement decreased pulmonary neutrophilia and IL-17A production in SR-BI-/- mice. Taken together, these data indicate that SR-BI dampens pulmonary neutrophilic inflammation and IL-17A production in allergic asthma at least in part by maintaining adrenal function.

Blood tryptase and thymic stromal lymphopoietin levels predict the risk of exacerbation in severe asthma

Some patients with severe asthma experience exacerbations despite receiving multiple therapy. The risk of exacerbation and heterogeneous response to treatment may be associated with specific inflammatory molecules that are responsive or resistant to corticosteroids. We aimed to identify the independent factors predictive for the future risk of exacerbation in patients with severe asthma. In this multi-center prospective observational study, 132 patients with severe asthma were enrolled and divided into exacerbation (n = 52) and non-exacerbation (n = 80) groups on the basis of exacerbation rate after a 1-year follow-up period. We found that previous history of severe-to-serious exacerbation, baseline blood eosinophil counts (≥ 291cells/μL), and serum tryptase (≤ 1448 pg/mL) and thrymic stromal lymphopoietin (TSLP) levels (≥ 25 pg/mL) independently predicted the future development of exacerbation with adjusted odds ratios (AOR) of 3.27, 6.04, 2.53 and 8.67, respectively. Notably, the patients with high blood eosinophil counts and low tryptase levels were likely to have more exacerbations than those with low blood eosinophil counts and high tryptase levels (AOR 16.9). TSLP potentially played the pathogenic role across different asthma phenotypes. TSLP and tryptase levels may be implicated in steroid resistance and responsiveness in the asthma inflammatory process. High blood eosinophil counts and low serum tryptase levels predict a high probability of future asthma exacerbation.

Sputum microbiome profiles identify severe asthma phenotypes of relative stability at 12 to 18 months

BACKGROUND

Asthma is a heterogeneous disease characterized by distinct phenotypes with associated microbial dysbiosis.

OBJECTIVES

Our aim was to identify severe asthma phenotypes based on sputum microbiome profiles and assess their stability after 12 to 18 months. A further aim was to evaluate clusters' robustness after inclusion of an independent cohort of patients with mild-to-moderate asthma.

METHODS

In this longitudinal multicenter cohort study, sputum samples were collected for microbiome profiling from a subset of the Unbiased Biomarkers in Prediction of Respiratory Disease Outcomes adult patient cohort at baseline and after 12 to 18 months of follow-up. Unsupervised hierarchical clustering was performed by using the Bray-Curtis β-diversity measure of microbial profiles. For internal validation, partitioning around medoids, consensus cluster distribution, bootstrapping, and topological data analysis were applied. Follow-up samples were studied to evaluate within-patient clustering stability in patients with severe asthma. Cluster robustness was evaluated by using an independent cohort of patients with mild-to-moderate asthma.

RESULTS

Data were available for 100 subjects with severe asthma (median age 55 years; 42% males). Two microbiome-driven clusters were identified; they were characterized by differences in asthma onset, smoking status, residential locations, percentage of blood and/or sputum neutrophils and macrophages, lung spirometry results, and concurrent asthma medications (all P values < .05). The cluster 2 patients displayed a commensal-deficient bacterial profile that was associated with worse asthma outcomes than those of the cluster 1 patients. Longitudinal clusters revealed high relative stability after 12 to 18 months in those with severe asthma. Further inclusion of an independent cohort of 24 patients with mild-to-moderate asthma was consistent with the clustering assignments.

CONCLUSION

Unbiased microbiome-driven clustering revealed 2 distinct robust phenotypes of severe asthma that exhibited relative overtime stability. This suggests that the sputum microbiome may serve as a biomarker for better characterizing asthma phenotypes.

The Future of Asthma Care: Personalized Asthma Treatment

Although once considered a single disease entity, asthma is now known to be a complex inflammatory disease engaging a range of causal pathways. The most frequent forms of asthma are identified by sputum/blood eosinophilia and activation of type 2 inflammatory pathways involving interleukins-3, -4, -5, and granulocyte-macrophage colony-stimulating factor. The use of diagnostics that identify T2 engagement linked to the selective use of highly targeted biologics has opened up a new way of managing severe disease. Novel technologies, such as wearables and intelligent inhalers, enable real-time remote monitoring of asthma, creating a unique opportunity for personalized health care.

Acute Respiratory Barrier Disruption by Ozone Exposure in Mice

Ozone exposure causes irritation, airway hyperreactivity (AHR), inflammation of the airways, and destruction of alveoli (emphysema), the gas exchange area of the lung in human and mice. This review focuses on the acute disruption of the respiratory epithelial barrier in mice. A single high dose ozone exposure (1 ppm for 1 h) causes first a break of the bronchiolar epithelium within 2 h with leak of serum proteins in the broncho-alveolar space, disruption of epithelial tight junctions and cell death, which is followed at 6 h by ROS activation, AHR, myeloid cell recruitment, and remodeling. High ROS levels activate a novel PGAM5 phosphatase dependent cell-death pathway, called oxeiptosis. Bronchiolar cell wall damage and inflammation upon a single ozone exposure are reversible. However, chronic ozone exposure leads to progressive and irreversible loss of alveolar epithelial cells and alveoli with reduced gas exchange space known as emphysema. It is further associated with chronic inflammation and fibrosis of the lung, resembling other environmental pollutants and cigarette smoke in pathogenesis of asthma, and chronic obstructive pulmonary disease (COPD). Here, we review recent data on the mechanisms of ozone induced injury on the different cell types and pathways with a focus on the role of the IL-1 family cytokines and the related IL-33. The relation of chronic ozone exposure induced lung disease with asthma and COPD and the fact that ozone exacerbates asthma and COPD is emphasized.

Diagnosis of severe asthma

Patients with asthma that is uncontrolled despite high intensity medication can present in both primary and specialist care. An increasing number of novel (and expensive) treatments are available for patients who fail conventional asthma therapy, but these may not be appropriate for all such patients. It is essential that a rigorous evaluation process be undertaken for these patients to identify those with biologically severe asthma who will require novel therapies, and those who may improve with control of contributory factors. In this article, we describe three key steps in the diagnostic evaluation process for severe asthma. The first step is confirmation of asthma diagnosis with objective evidence of variable airflow obstruction. The second involves management of contributory factors such as non-adherence, poor inhaler technique, ongoing asthma triggers, and comorbidities. The third step involves phenotyping and endotyping of patients with severe asthma. We provide a practical approach to implementing these measures in both primary and secondary care.

A Novel TNF-α-Targeting Aptamer for TNF-α-Mediated Acute Lung Injury and Acute Liver Failure

Rationale: The TNF-α pathway plays as a double-edged sword that simultaneously regulates cell apoptosis and proliferation. The dysregulated TNF-α signaling can trigger cytokine storms that lead to profound cell death during the phase of acute tissue injury. On the other hand, an optimal level of TNF-α signaling is required for tissue repair following the acute injury phase. The TNF-α pathway is commonly upregulated in acute lung injury (ALI) and acute liver failure (ALF). Previous studies investigated the feasibility of adopting protein-based TNF-α blockers as disease modifiers in ALI and ALF, but none of these came out with a positive result. One of the potential reasons that resides behind the failure of the trials might be the long half-life of these inhibitors that led to undesired side effects. Developing alternative TNF-α blockers with manageable half-lives remain an unmet need in this regard.

Methods: In the current study, we developed a novel TNF-α-targeting aptamer (aptTNF-α) and its PEG-derivate (aptTNF-α-PEG) with antagonistic functions. We investigated the in vivo antagonistic effects using mouse ALI and ALF models.

Results: Our data showed that aptTNF-α possessed good in vitro binding affinity towards human/mouse TNF-α and successfully targeted TNF-α in vivo. In the mouse ALI model, aptTNF-α/aptTNF-α-PEG treatment attenuated the severity of LPS-induced ALI, as indicated by the improvement of oxygen saturation and lung injury scores, the reduction of protein-rich fluid leakage and neutrophil infiltration in the alveolar spaces, and the suppression of pro-inflammatory cytokines/chemokines expressions in the lung tissues. In the mouse ALF model, we further showed that aptTNF-α/aptTNF-α-PEG treatment not only attenuated the degree of hepatocyte damage upon acute injury but also potentiated early regeneration of the liver tissues.

Conclusion: The results implicated potential roles of aptTNF-α/aptTNF-α-PEG in ALI and ALF. The data also suggested their translational potential as a new category of TNF-α blocking agent.

NETopathic Inflammation in Chronic Obstructive Pulmonary Disease and Severe Asthma

Neutrophils play a central role in innate immunity, inflammation, and resolution. Unresolving neutrophilia features as a disrupted inflammatory process in the airways of patients with chronic obstructive pulmonary disease (COPD) and severe asthma. The extent to which this may be linked to disease pathobiology remains obscure and could be further confounded by indication of glucocorticoids or concomitant respiratory infections. The formation of neutrophil extracellular traps (NETs) represents a specialized host defense mechanism that entrap and eliminate invading microbes. NETs are web-like scaffolds of extracellular DNA in complex with histones and neutrophil granular proteins, such as myeloperoxidase and neutrophil elastase. Distinct from apoptosis, NET formation is an active form of cell death that could be triggered by various microbial, inflammatory, and endogenous or exogenous stimuli. NETs are reportedly enriched in neutrophil-dominant refractory lung diseases, such as COPD and severe asthma. Evidence for a pathogenic role for respiratory viruses (e.g., Rhinovirus), bacteria (e.g., Staphylococcus aureus) and fungi (e.g., Aspergillus fumigatus) in NET induction is emerging. Dysregulation of this process may exert localized NET burden and contribute to NETopathic lung inflammation. Disentangling the role of NETs in human health and disease offer unique opportunities for therapeutic modulation. The chemokine CXCR2 receptor regulates neutrophil activation and migration, and small molecule CXCR2 antagonists (e.g., AZD5069, danirixin) have been developed to selectively block neutrophilic inflammatory pathways. NET-stabilizing agents using CXCR2 antagonists are being investigated in proof-of-concept studies in patients with COPD to provide mechanistic insights. Clinical validation of this type could lead to novel therapeutics for multiple CXCR2-related NETopathologies. In this Review, we discuss the emerging role of NETs in the clinicopathobiology of COPD and severe asthma and provide an outlook on how novel NET-stabilizing therapies via CXCR2 blockade could be leveraged to disrupt NETopathic inflammation in disease-specific phenotypes.

Total serum IgE levels among adults patients with intermittent and persistent allergic asthmas

Background: Obesity with knee osteoarthritis (OA) is related to chronic pain causing physical inactivity that leads to decreased cardiorespiratory endurance and quality of life. Aquatic and land-based exercises are effective in improving physical activity. The aim of this study is to compare between aquatic and land-based exercise to improve cardiorespiratory endurance and quality of life in obese patients with knee osteoarthritis.Methods: A single-blind, randomized, controlled trial was conducted on thirty-three obese patients with knee OA who visited Obesity Clinic of Medical Rehabilitation Cipto Mangunkusumo Hospital, from October 2016 to January 2017, subjects were divided into aquatic or land-based exercise group. Aerobic and knee-strengthening exercises were given. Cardiorespiratory endurance was assessed using the Borg Scale, whereas both the BORG CR-10 and SF-36 questionnaires were used to assess quality of life.Results: After intervention, there were significant improvements in the land-based exercise group in the rating of perceived exertion (p=0.02), role limitations due to physical health (p=0.024), role limitations due to emotional problems (p=0.041), energy/fatigue (p=0.016), and the decline in pain (p=0.049) parameters. While in the aquatic exercise, there were significant improvements in leg fatigue (p=0.016), energy/fatigue (p=0.025), emotional well-being (p<0.001), and general health (p=0.045) parameters. Despite this, there were no significant differences between two groups regarding cardiorespiratory endurance and quality of life.Conclusion: This study found that patients could start aquatic exercise to reduce leg fatigue and enhance general health and energy. After that, exercise could be continued in land-based settings to improve cardiorespiratory endurance and quality of life.

Serum sST2 levels predict severe exacerbation of asthma

BACKGROUND

Neutrophilic inflammation is associated with poorly controlled asthma. Serum levels of sST2, a soluble IL-33 receptor, increase in neutrophilic lung diseases. We hypothesized that high serum sST2 levels in stable asthmatics are a predictor for exacerbation within a short duration.

METHODS

This prospective observational study evaluated the serum sST2 levels of 104 asthmatic patients who were treated by a lung disease specialist with follow-ups for 3 months.

RESULTS

High serum sST2 levels (> 18 ng/ml) predicted severe asthma exacerbation within 3 months. Serum sST2 levels correlated positively with asthma severity (treatment step), airway H2O2 levels, and serum IL-8 levels. High serum sST2 levels and blood neutrophilia (> 6000 /μl) were independent predictors of exacerbation. We defined a post-hoc exacerbation-risk score combining high serum sST2 level and blood neutrophilia, which stratified patients into four groups. The score predicted exacerbation-risk with an area under curve of 0.91 in the receiver operating characteristic curve analysis. Patients with the highest scores had the most severe phenotype, with 85.7% showing exacerbation, airflow limitation, and corticosteroid-insensitivity.

CONCLUSIONS

High serum sST2 levels predicted exacerbation within the general asthmatic population and, when combined with blood neutrophil levels, provided an exacerbation-risk score that was an accurate predictor of exacerbation occurring within 3 months.

Precision medicine in asthma: linking phenotypes to targeted treatments

PURPOSE OF REVIEW

Asthma is a heterogeneous disease consisting of different phenotypes that are driven by different mechanistic pathways. The purpose of this review is to emphasize the important role of precision medicine in asthma management.

RECENT FINDINGS

Despite asthma heterogeneity, the approach to management has been on the basis of disease severity, with the most severe patients reserved for the maximum treatments with corticosteroids and bronchodilators. At the severe end, the recent availability of biologic therapies in the form of anti-IgE (omalizumab) and anti-IL5 therapies (mepolizumab and reslizumab) has driven the adaptation of precision medicine. These therapies are reserved for severe asthma with defined either allergic or eosinophilic background, respectively.

SUMMARY

Unbiased definition of phenotypes or endotypes (which are phenotypes defined by mechanisms) is an important step towards the use of precision medicine in asthma. Although T2-high asthma has been defined with targets becoming available for treating allergic or eosinophilic asthma, the definition of non-T2 phenotypes remains a priority. Precision medicine is also dependent on the definition of biomarkers that can help differentiate between these phenotypes and pinpoint patients suitable for specific-targeted therapies. Thus, precision medicine links phenotypes (endotypes) to targeted treatments for better outcomes.

Asthma: personalized and precision medicine

PURPOSE OF REVIEW

In this review, we herein describe the progress in management of severe asthma, evolving from a 'blockbuster approach' to a more personalized approach targeted to the utilization of endotype-driven therapies.

RECENT FINDINGS

Severe asthma characterization in phenotypes and endotypes, by means of specific biomarkers, have led to the dichotomization of the concepts of 'personalized medicine' and 'precision medicine', which are often used as synonyms, but actually have conceptual differences in meaning. The recent contribute of the omic sciences (i.e. proteomics, transcriptomics, metabolomics, genomics, …) has brought this initially theoretic evolution into a more concrete level.

SUMMARY

This step-by-step transition would bring to a better approach to severe asthmatic patients as the personalization of their therapeutic strategy would bring to a better patient selection, a more precise endotype-driven treatment, and hopefully to better results in terms of reduction of exacerbation rates, symptoms, pulmonary function and quality of life.

Lung Function Trajectory Types in Never-Smoking Adults With Asthma: Clinical Features and Inflammatory Patterns

Purpose

Asthma is a heterogeneous disease that responds to medications to varying degrees. Cluster analyses have identified several phenotypes and variables related to fixed airway obstruction; however, few longitudinal studies of lung function have been performed on adult asthmatics. We investigated clinical, demographic, and inflammatory factors related to persistent airflow limitation based on lung function trajectories over 1 year.

Methods

Serial post-bronchodilator forced expiratory volume (FEV) 1% values were obtained from 1,679 asthmatics who were followed up every 3 months for 1 year. First, a hierarchical cluster analysis was performed using Ward's method to generate a dendrogram for the optimum number of clusters using the complete post-FEV1 sets from 448 subjects. Then, a trajectory cluster analysis of serial post-FEV1 sets was performed using the k-means clustering for the longitudinal data trajectory method. Next, trajectory clustering for the serial post-FEV1 sets of a total of 1,679 asthmatics was performed after imputation of missing post-FEV1 values using regression methods.

Results

Trajectories 1 and 2 were associated with normal lung function during the study period, and trajectory 3 was associated with a reversal to normal of the moderately decreased baseline FEV1 within 3 months. Trajectories 4 and 5 were associated with severe asthma with a marked reduction in baseline FEV1. However, the FEV1 associated with trajectory 4 was increased at 3 months, whereas the FEV1 associated with trajectory 5 was persistently disturbed over 1 year. Compared with trajectory 4, trajectory 5 was associated with older asthmatics with less atopy, a lower immunoglobulin E (IgE) level, sputum neutrophilia and higher dosages of oral steroids. In contrast, trajectory 4 was associated with higher sputum and blood eosinophil counts and more frequent exacerbations.

Conclusions

Trajectory clustering analysis of FEV1 identified 5 distinct types, representing well-preserved to severely decreased FEV1. Persistent airflow obstruction may be related to non-atopy, a low IgE level, and older age accompanied by neutrophilic inflammation and low baseline FEV1 levels.

The Contribution of Oxidative Stress and Inflamm-Aging in Human and Equine Asthma

Aging is associated with a dysregulation of the immune system, leading to a general pro-inflammatory state of the organism, a process that has been named inflamm-aging. Oxidative stress has an important role in aging and in the regulation of immune responses, probably playing a role in the development of age-related diseases. The respiratory system function physiologically declines with the advancement of age. In elderly asthmatic patients, this may contribute to disease expression. In this review, we will focus on age-related changes affecting the immune system and in respiratory structure and function that could contribute to asthma occurrence, and/or clinical presentation in the elderly. Also, naturally occurring equine asthma will be discussed as a possible model for studying the importance of oxidative stress and immun-aging/inflamm-aging in humans.