Clinical and biological factors associated with irreversible airway obstruction in adult asthma

Bronchodilator Responsiveness Measured by Spirometry and Impulse Oscillometry in Patients with Asthma After Short Acting Antimuscarinic and/or Beta-2-Agonists Inhalation

Background

Bronchodilator responsiveness (BDR) in asthma involves both the central and peripheral airways but is primarily relieved with beta-2-agonists and evaluated by spirometry. To date, antimuscarinics can be added as a reliever medication in more severe asthma. We hypothesize that combining both short-acting beta-2 agonist (SABA) and short-acting muscarinic antagonist (SAMA) could also improve the responsiveness in mild-moderate asthma. Therefore, we aimed to compare the direct effects of inhaling SABA alone, SAMA alone or combining both SABA and SAMA on the central and peripheral airways in asthma.

Methods

Twenty-three patients with mild-moderate BDR in asthma performed dynamic spirometry and impulse oscillometry before (baseline) and multiple timepoints within an hour after inhalation of SABA (salbutamol), SAMA (ipratropium bromide), or both SABA and SAMA at three different visits.

Results

The use of SAMA alone did not show any improvement compared to the use of SABA alone. Inhalation of SABA+SAMA, however, averaged either similar or better BDR than SABA alone in FEV1, MMEF, FVC, R5, R20 and R5-R20. Inhaling SABA+SAMA reached a stable BDR in more patients within 0-10 minutes and also reached the FEV1 (Δ%)>12% faster (3.5 minutes) than inhaling SABA alone (5.1 minutes). Inhaling SABA+SAMA was significantly better than SAMA alone in FEV1 (p = 0.015), MMEF (p = 0.0059) and R20 (p = 0.0049). Using these three variables highlighted a subgroup (30%, including more males) of patients that were more responsive to inhaling SABA+SAMA than SABA alone.

Conclusion

Overall, combining SAMA with SABA was faster and more consistent at increasing the lung function than SABA alone or SAMA alone, and the additive effect was best captured by incorporating peripheral-related variables. Therefore, SAMA should be considered as an add-on reliever for mild-moderate patients with BDR in asthma.

Benralizumab in severe eosinophilic asthma in real life: confirmed effectiveness and contrasted effect on sputum eosinophilia versus exhaled nitric oxide fraction - PROMISE

Background

Randomised controlled trials have shown that benralizumab, an anti-interleukin-5 receptor monoclonal antibody, reduces exacerbations and oral corticosteroid dose and improves asthma control and lung function in severe eosinophilic asthma. The aim of this study was to confirm results of randomised controlled trials in real life in a population of 73 patients with severe eosinophilic asthma treated with benralizumab for at least 12 months.

Methods

Patients underwent careful monitoring of asthma exacerbations, exhaled nitric oxide fraction, lung function, asthma control and quality of life questionnaire responses and sputum induction, and gave a blood sample at baseline, after 6 months and then every year.

Results

We found significant reductions in exacerbations (by 92%, p<0.0001) and oral corticosteroid dose (by 83%, p<0.001) after 6 months that were maintained over time, with 78% of patients able to stop oral corticosteroid therapy. Patients improved their Asthma Control Test (ACT) score (from 11.7±5.1 to 16.9±5.35, p<0.0001), Asthma Control Questionnaire (ACQ) score (from 2.88±1.26 to 1.77±1.32, p<0.0001) and Asthma Quality of Life Questionnaire score (+1.04, p<0.0001) at 6 months and this was maintained during follow-up. Only 35% and 43% of patients reached asthma control according to an ACT score ≥20 and ACQ score <1.5, respectively. We observed stable post-bronchodilation lung function over time and a significant reduction in sputum eosinophil count, with 85% of patients exhibiting sputum eosinophil counts <3% after 6 months (p<0.01) with no effect on exhaled nitric oxide fraction.

Conclusion

In our real-life study, we confirm the results published in randomised controlled trials showing a sharp reduction in exacerbations and oral corticosteroid therapy, an improvement in asthma control and quality of life, and a dramatic reduction in sputum eosinophil count.

Comparison with gastric cancer-associated genes reveals the role of ferroptosis-related genes in eosinophils of asthma patients: A bioinformatic study

Ferroptosis-inducing agents (FIAs) induced lipid-peroxidation-independent ferroptosis in eosinophils, thus ameliorating airway inflammation in asthmatic mice. Differences in ferroptosis-related genes (FerrGs) between eosinophils and cells in which FIAs induce canonical ferroptosis are supposed to contribute to this noncanonical ferroptosis but remain unclear. This study aims to explore these differences. This study used gastric cancer cells (GCCs) in stomach adenocarcinoma as the representative of cells in which FIAs induce canonical ferroptosis. FerrGs in Ferroptosis Database V2 respectively intersected with differentially expressed genes (DEGs) of eosinophils (E-MTAB-4660 dataset) and GCCs (GEPIA2 Stomach adenocarcinoma dataset) to obtain original ferroptosis DEGs (FerrDEGs). Then, they were subjected to Venn analysis to identify FerrDEGs shared by them and FerrDEGs exclusively expressed in eosinophils or GCCs. Identified genes were subjected to functional enrichment analysis, protein-protein interactions analysis, Hub genes analysis, and construction of the LncRNA-mediated ceRNA network. Sixty-six original FerrDEGs in eosinophils and 110 original FerrDEGs in GCCs were obtained. Venn analysis identified that eosinophils and GCCs shared 19 FerrDEGs that presented opposite expression directions and were involved in the ferroptosis pathway. Four upregulated and 20 downregulated FerrDEGs were exclusively expressed in eosinophils and GCCs, respectively. The former were enriched only in glycerolipid metabolism, while the latter were not enriched in pathways. Forty downregulated and 68 upregulated FerrDEGs were solely expressed in eosinophils and GCCs, respectively. The former was associated with the FoxO signaling pathway; the latter was related to glutathione metabolism and they were all implicated in autophagy. PPI analysis shows that the top 10 Hub genes of 66 original FerrDEGs and 44 exclusive FerrDEGs in eosinophils shared 9 genes (STAT3, NFE2L2, MAPK8, PTEN, MAPK3, TLR4, SIRT1, BECN1, and PTGS2) and they were also involved in the FoxO signaling pathway and autophagy pathway. Among them, PTEN is involved in forming a ceRNA network containing 3 LncRNAs, 3 miRNAs and 3 mRNAs. In contrast to FerrGs in cells in which FIAs induce canonical ferroptosis, the FerrGs in eosinophils differ in expression and in the regulation of ferroptosis, FoxO signaling pathway, and autophagy. It lays the groundwork for targeted induction of eosinophils lipid-peroxidation-independent ferroptosis in asthma.

The Pathology of Asthma: What Is Obstructing Our View?

Despite the advent of sophisticated and efficient new biologics to treat inflammation in asthma, the disease persists. Even following treatment, many patients still experience the well-known symptoms of wheezing, shortness of breath, and coughing. What are we missing? Here we examine the evidence that mucus plugs contribute to a substantial portion of disease, not only by physically obstructing the airways but also by perpetuating inflammation. In this way, mucus plugs may act as an immunogenic stimulus even in the absence of allergen or with the use of current therapeutics. The alterations of several parameters of mucus biology, driven by type 2 inflammation, result in sticky and tenacious sputum, which represents a potent threat, first due to the difficulties in expectoration and second by acting as a platform for viral, bacterial, or fungal colonization that allows exacerbations. Therefore, in this way, mucus plugs are an overlooked but critical feature of asthmatic airway disease.

Different clinical characteristics of current smokers and former smokers with asthma: a cross-sectional study of adult asthma patients in China

Smoking is a trigger for asthma, which has led to an increase in asthma incidence in China. In smokers, asthma management starts with smoking cessation. Data on predictors of smoking cessation in Chinese patients with asthma are scarce. The objective of this study was to find the differences in clinical characteristics between current smokers and former smokers with asthma in order to identify factors associated with smoking cessation. Eligible adults with diagnosed asthma and smoking from the hospital outpatient clinics (n = 2312) were enrolled and underwent a clinical evaluation, asthma control test (ACT), and pulmonary function test. Information on demographic and sociological data, lung function, laboratory tests, ACT and asthma control questionnaire (ACQ) scores was recorded. Patients were divided into a current smokers group and a former smokers group based on whether they had quit smoking. Logistic regression analysis was used to analyze the factors associated with smoking cessation. Of all patients with asthma, 34.6% were smokers and 65.4% were former smokers, and the mean age was 54.5 ± 11.5 years. Compared with current smokers, the former smokers were older, had longer duration of asthma, had higher ICS dose, had more partially controlled and uncontrolled asthma, had more pack-years, had smoked for longer, and had worse asthma control. The logistic regression model showed that smoking cessation was positively correlated with age, female sex, pack-years, years of smoking, partially controlled asthma, uncontrolled asthma, and body mass index (BMI), but was negatively correlated with ACT, FEV₁, FEV₁%predicted, and widowed status. More than 30% of asthma patients in the study were still smoking. Among those who quit smoking, many quit late, often not realizing they need to quit until they have significant breathing difficulties. The related factors of smoking cessation identified in this study indicate that there are still differences between continuing smokers and former smokers, and these factors should be focused on in asthma smoking cessation interventions to improve the prognosis of patients with asthma.

Concomitant preoperative airflow obstruction confers worse prognosis after trans-thoracic surgery for esophageal cancer

Background

Airflow obstruction is a critical element of chronic airway diseases. This study aimed to evaluate the impact of preoperative airflow obstruction on the prognosis of patients following surgery for esophageal carcinoma.

Methods

A total of 821 esophageal cancer patients were included and classified into two groups based on whether or not they had preoperative airflow obstruction. Airflow obstruction was defined as a forced expiration volume in the first second (FEV₁)/forced vital capacity (FVC) ratio below the lower limit of normal (LLN). A retrospective analysis of the impact of airflow obstruction on the survival of patients with esophageal carcinoma undergoing esophagectomy was performed.

Results

Patients with airflow obstruction (102/821, 12.4%) had lower three-year overall (42/102, 58.8%) and progression-free survival rate (47/102, 53.9%) than those without airflow obstruction (P < 0.001). Multivariate analyses showed that airflow obstruction was an independent risk factor for overall survival (Hazard Ratio = 1.66; 95% CI: 1.17-2.35, P = 0.004) and disease progression (Hazard Ratio = 1.51; 95% CI: 1.1-2.08; P = 0.01). A subgroup analysis revealed that the above results were more significant in male patients, BMI < 23 kg/m² patients or late-stage cancer (stage III-IVA) (P = 0.001) patients and those undergoing open esophagectomy (P < 0.001).

Conclusion

Preoperative airflow obstruction defined by FEV₁/FVC ratio below LLN was an independent risk factor for mortality in esophageal cancer patients after trans-thoracic esophagectomy. Comprehensive management of airflow obstruction and more personalized surgical decision-making are necessary to improve survival outcomes in esophageal cancer patients.

Longitudinal assessment of loss and gain of lung function in childhood asthma

OBJECTIVE

The Childhood Asthma Management Program revealed that 25.7% of children with mild to moderate asthma exhibit loss of lung function. The objective was to assess the trajectories of function by means of serial FEV₁ in asthmatic children participating in out-of-hospital follow-up.

METHODS

A total of 295 children (199 boys) who had undergone at least 10 spirometry tests from the age of 8 were selected from a single-center open cohort. The annualized rate of change (slope) for prebronchodilator FEV₁ (percent predicted) was estimated for each participant and three patterns were defined: significantly positive slope, significantly negative slope, and null slope (non-significant P-value; Pearson test). The standard deviation (SD) of each individual slope was recorded as a variability criterion of FEV₁.

RESULTS

The median (25^th; 75^th percentile) age at inclusion and the last visit was 8.5 (8.2; 9.3) and 15.4 (14.8, 16.0) years, respectively. Tracking of function (null slope) was observed in 68.8% of the children, while 27.8% showed a loss of function or reduced growth (negative slope) and 3.4% showed a gain in function (positive slope). The children characterized by loss of function depicted a better initial function and a lower FEV₁ variability during their follow-up than children with tracking or gain of lung function. At the last visit, these children were characterized by a lower lung function than children with tracking or gain of lung function.

CONCLUSION

Better initial FEV₁ value and less FEV₁ variability are associated with loss of lung function or reduced lung growth in asthmatic children.

Suppression of airway allergic eosinophilia by Hp-TGM, a helminth mimic of TGF-β

Type 2-high asthma is a chronic inflammatory disease of the airways which is increasingly prevalent in countries where helminth parasite infections are rare, and characterized by T helper 2 (Th2)-dependent accumulation of eosinophils in the lungs. Regulatory cytokines such as TGF-β can restrain inflammatory reactions, dampen allergic Th2 responses, and control eosinophil activation. The murine helminth parasite Heligmosomoides polygyrus releases a TGF-β mimic (Hp-TGM) that replicates the biological and functional properties of TGF-β despite bearing no structural similarity to the mammalian protein. Here, we investigated if Hp-TGM could alleviate allergic airway inflammation in mice exposed to Alternaria alternata allergen, house dust mite (HDM) extract or alum-adjuvanted ovalbumin protein (OVA). Intranasal administration of Hp-TGM during Alternaria exposure sharply reduced airway and lung tissue eosinophilia along with bronchoalveolar lavage fluid IL-5 and lung IL-33 cytokine levels at 24 h. The protective effect of Hp-TGM on airway eosinophilia was also obtained in the longer T-cell mediated models of HDM or OVA sensitisation with significant inhibition of eotaxin-1, IL-4 and IL-13 responses depending on the model and time-point. Hp-TGM was also protective when administered parenterally either when given at the time of allergic sensitisation or during airway allergen challenge. This project has taken the first steps in identifying the role of Hp-TGM in allergic asthma and highlighted its ability to control lung inflammation and allergic pathology. Future research will investigate the mode of action of Hp-TGM against airway allergic eosinophilia, and further explore its potential to be developed as a biotherapeutic in allergic asthma.

Asthma and Tobacco Smoking

Asthma is a prevalent chronic pulmonary condition with significant morbidity and mortality. Tobacco smoking is implicated in asthma pathophysiology, diagnosis, prognosis and treatment. Smokers display increased prevalence and incidence of asthma, but a causal association cannot be claimed using existing evidence. Second-hand smoking and passive exposure to tobacco in utero and early life have also been linked with asthma development. Currently, approximately one-fourth of asthma patients are smokers. Regular smokers with asthma might display accelerated lung function decline and non-reversible airflow limitation, making their distinction from chronic obstructive pulmonary disease patients challenging. Asthma patients who smoke typically have uncontrolled disease, as shown by increased symptoms, more exacerbations and impaired quality of life. On the other hand, smoking cessation improves lung function and asthma severity. Thus, asthma patients and their caregivers should be actively questioned about their smoking status at each medical encounter, and smoking cessation ought to be strongly encouraged both for patients with asthma and their close contacts. Smokers with asthma should be provided with comprehensive smoking cessation interventions on top of other anti-asthma medications.

European Respiratory Society Guidelines for the Diagnosis of Asthma in Adults

Although asthma is very common affecting 5-10% of the population, the diagnosis of asthma in adults remains a challenge in the real world that results in both over- and under-diagnosis. A task force (TF) was set up by the European Respiratory Society to systematically review the literature on the diagnostic accuracy of tests used to diagnose asthma in adult patients and provide recommendation for clinical practice.The TF defined eight PICO (Population, Index, Comparator, and Outcome) questions that were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach, The TF utilised the outcomes to develop an evidenced-based diagnostic algorithm, with recommendations for a pragmatic guideline for everyday practice that was directed by real-life patient experiences.The TF support the initial use of spirometry followed, and if airway obstruction is present, by bronchodilator reversibility testing. If initial spirometry fails to show obstruction, further tests should be performed in the following order: FeNO, PEF variability or in secondary care, bronchial challenge. We present the thresholds for each test that are compatible with a diagnosis of asthma in the presence of current symptoms.The TF reinforce the priority to undertake spirometry and recognise the value of measuring blood eosinophils and serum IgE to phenotype the patient. Measuring gas trapping by body plethysmography in patients with preserved FEV1/FVC ratio deserves further attention. The TF draw attention on the difficulty of making a correct diagnosis in patients already receiving inhaled corticosteroids, the comorbidities that may obscure the diagnosis, the importance of phenotyping, and the necessity to consider the patient experience in the diagnostic process.

Treatment response among asthmatic patients with and without reversible airflow limitations

Objectives

Asthma is a chronic airway disorder associated with variable airflow limitations, which are triggered by different stimuli. The reversibility of airflow limitations reflects patients' responses to the therapy with bronchodilators and improvements in airflow. This study aims to determine the treatment outcomes (improvements in forced expiratory volume in the first second (FEV1) and the number of asthma exacerbations) associated with the presence of airflow reversibility.

Methods

This retrospective cohort study included 154 adults (>18 years) who were diagnosed with asthma and had pulmonary function testing (PFT) at a tertiary care centre in KSA between January 1st, 2014 and May 31st, 2019. Smokers and patients with comorbidities or medications that could affect PFT were excluded from the analysis. Patients were classified as having a reversible airflow limitation when they exhibited a post-bronchodilator FEV1 increase of 12% and 200 mL. Exacerbations were defined as the need to use oral corticosteroids. Chi-square tests were used for comparative analyses.

Results

From our cohort, 42 patients exhibited reversibility. In contrast, 112 patients did not show any sign of reversibility. Asthmatics with baseline reversible airflow limitations experienced significant worsening of FEV1 during the follow-up period compared with those with no reversibility, showing a mean difference of 19.96 mL (p = 0.0206). There was no significant association between asthma reversibility and exacerbations (p = 0.23).

Conclusion

In our study, during the follow-up of patients with asthma, we found that the reversibility of airflow was associated with significantly worse FEV1, although this did not have a significant effect on exacerbations. Therefore, we recommend regular spirometry follow-ups, particularly for patients with significant airway reversibility.

Immune responses and exacerbations in severe asthma

Asthma as a clinical entity manifests with a broad spectrum of disease severity. Unlike milder asthma, severe disease is poorly controlled by inhaled corticosteroids, the current standard of care. Transcriptomic data, along with patient characteristics and response to biologics show that though Type 2 (T2) immune response remains an integral feature of asthma, additional molecular and immunologic factors may play important roles in pathogenesis. Mechanisms of T2 development, cellular sources of T2 cytokines and their relationship to additional immune pathways concurrently activated may distinguish several different subphenotypes, and perhaps endotypes of asthma, with differential response to non-specific and targeted anti-inflammatory therapies. Recent data have also associated non-T2 cytokines derived from T cells, particularly IFN-γ, and epithelial mediators with severe asthma. These topics and their relationships to acute asthma exacerbations are discussed in this review.

Anti-Interleukin-5 Therapy Is Associated with Attenuated Lung Function Decline in Severe Eosinophilic Asthma Patients from the Belgian Severe Asthma Registry

BACKGROUND

Asthmatics have accelerated lung function decline over time compared with healthy individuals.

OBJECTIVE

To evaluate risk factors for accelerated lung function decline.

METHODS

In a longitudinal analysis on severe asthmatics enrolled in the Belgian Severe Asthma Registry with at least 2 visits a minimum of 12 months apart, we compared characteristics of patients with and without decline (loss of post-bronchodilation forced expiratory volume in 1 s [FEV₁] (% predicted)/y greater than zero) over time. Multiple linear regression was applied to study the factors independently associated with FEV₁ decline.

RESULTS

In the overall population (n = 318), median annual FEV₁ decline was 0.27 (-4.22 to 3.80) % predicted/y over a period of 23 months (12-41 months). Asthma was less controlled at baseline in nondecliners than in decliners (53%). Lung function and residual volume at baseline were higher in the declining group. Decliners presented with increased bronchial reactivity (ie, a lower provocative concentration of methacholine causing a 20% fall in FEV₁) at baseline. Twenty-five percent of nondecliners were started on anti-interleukin-5 (anti-IL-5) for severe eosinophilic asthma during the study compared with 10% of decliners. The multivariable model suggested that Asthma Control Questionnaire score at baseline, late-onset asthma, and addition of anti-IL-5 during follow-up were associated with lower FEV₁ decline, independently from other variables such as evolution in exacerbations, smoking status, inhaled corticosteroids or oral corticosteroids dose, or add-on anti-immunoglobulin E over time, whereas reversibility to salbutamol and higher FEV₁ were associated with accelerated FEV₁ decline.

CONCLUSIONS

Add-on therapy with anti-IL-5 in severe eosinophilic asthma was associated with an attenuated FEV₁ decline. The causality of this observation should, however, be confirmed in future prospective controlled studies.

Regulatory effect of NLRP3 on airway inflammatory response and pyroptosis in mice with asthma

OBJECTIVES

To study the regulatory effect of the NOD-like receptor, pyrin domain-containing 3 (NLRP3) on airway inflammatory response and pyroptosis in mice with asthma.

METHODS

The NLRP3 wild-type (WT) C57BL/6J mice were divided into two groups: NLRP3-WT control and NLRP3-WT asthma. The mice with NLRP3 knockout (KO) were divided into two groups: NLRP3-KO control and NLRP3-KO asthma (n=10 each). A model of asthma was prepared by intraperitoneal injection of ovalbumin + aluminium hydroxide for sensitization and ovalbumin inhalation for challenge. Enhanced pause, an index for airway responsiveness, was measured for each group. Hematoxylin and eosin staining was used to observe the histomorphological changes of lungs and determine the inflammation score for each group. Bronchoalveolar lavage fluid was collected from each group to determine the numbers of neutrophils, eosinophils, and lymphocytes and measure the content of interleukin-1β (IL-1β) and interleukin-18 (IL-18). Western blot was used to measure the expression of NLRP3, cleaved caspase-1, and Gasdermin D-N in lung tissue of each group.

RESULTS

Compared with the NLRP3-WT control group, the NLRP3-WT asthma group showed morphological changes including airway smooth muscle thickening and inflammatory cell infiltration. Compared with the NLRP3-WT asthma group, the NLRP3-KO asthma group had significant improvements in the above morphological manifestations. Compared with the NLRP3-WT control group, the NLRP3-WT asthma group had significant increases in the enhanced pause, the inflammation score of lung tissue, the numbers of neutrophils, eosinophils and lymphocytes in bronchoalveolar lavage fluid, and the levels of IL-1β and IL-18 in bronchoalveolar lavage fluid (P<0.05). The expression of NLRP3, cleaved caspase-1, and Gasdermin D-N in lung tissue also significantly increased in the NLRP3-WT asthma group (P<0.05). The above indices in the NLRP3-KO asthma group were significantly lower than those in the NLRP3-WT asthma group (P<0.05).

CONCLUSIONS

The overexpression of NLRP3 is associated with the pathogenesis of asthma, which may be related to the molecular mechanisms of the activation of airway inflammatory response and pyroptosis. Citation.

The basic immunology of asthma

In many asthmatics, chronic airway inflammation is driven by IL-4-, IL-5-, and IL-13-producing Th2 cells or ILC2s. Type 2 cytokines promote hallmark features of the disease such as eosinophilia, mucus hypersecretion, bronchial hyperresponsiveness (BHR), IgE production, and susceptibility to exacerbations. However, only half the asthmatics have this "type 2-high" signature, and "type 2-low" asthma is more associated with obesity, presence of neutrophils, and unresponsiveness to corticosteroids, the mainstay asthma therapy. Here, we review the underlying immunological basis of various asthma endotypes by discussing results obtained from animal studies as well as results generated in clinical studies targeting specific immune pathways.