Biomarker-based asthma phenotypes of corticosteroid response

Breath and Sputum Analyses in Asthmatic Patients: An Overview

Recent advancements in asthma management include non-invasive methodologies such as sputum analysis, exhaled breath condensate (EBC), and fractional exhaled nitric oxide (FeNO). These techniques offer a means to assess airway inflammation, a critical feature of asthma, without invasive procedures. Sputum analysis provides detailed insights into airway inflammation patterns and cellular composition, guiding personalized treatment strategies. EBC collection, reflecting bronchoalveolar lining fluid composition, provides a non-invasive window into airway physiology. FeNO emerges as a pivotal biomarker, offering insights into eosinophilic airway inflammation and aiding in asthma diagnosis, treatment monitoring, and the prediction of exacerbation risks. Despite inherent limitations, each method offers valuable tools for a more comprehensive assessment of asthma. Combining these techniques with traditional methods like spirometry may lead to more personalized treatment plans and improved patient outcomes. Future research is crucial to refine protocols, validate biomarkers, and establish comprehensive guidelines in order to enhance asthma management with tailored therapeutic strategies and improved patient outcomes.

Domiciliary monitoring of exhaled nitric oxide in the management of asthma: a pilot study

BACKGROUND

Whether asthma patients could benefit from home monitoring for fractional exhaled nitric oxide (flow of 50 mL/s, FeNO50) is unknown. We explore the application value of home monitoring FeNO50 in daily asthma management.

METHODS

Twenty-two untreated, uncontrolled asthma patients were selected. Medical history, blood and sputum samples, pulmonary function, Asthma Control Test (ACT), and other clinical data of the subjects were collected. All subjects underwent daily monitoring for four weeks using a FeNO50 monitor and mobile spirometry (mSpirometry). The diurnal differences and dynamic changes were described. Compare the effect-acting time and the relative plateau of treatment between FeNO50 and mSpirometry monitoring.

RESULTS

In the first two weeks, the morning median (IQR) level of FeNO50 was 44 (35, 56) ppb, which was significantly higher than the evening median level [41 (32, 53) ppb, P = 0.028]. The median (IQR) effect-acting time assessed by FeNO50 was 4 (3, 5) days, which was significantly earlier than each measure of mSpirometry (P < 0.05). FeNO50 reached the relative plateau significantly earlier than FEV1 (15 ± 2 days vs. 21 ± 3 days, P < 0.001). After treatment, the daily and weekly variation rates of FeNO50 showed a gradually decreasing trend (P < 0.05). The ACT score, sputum eosinophils, and blood eosinophils also significantly improved (P ≤ 0.01).

CONCLUSIONS

The daily home monitoring of FeNO50 in asthmatic patients showed significant circadian rhythm, and the sensitivity of FeNO50 in evaluating the response to treatment was higher than mSpirometry. The daily and weekly variation rates of FeNO50 change dynamically with time, which may be used to assess the condition of asthma.

Eosinophilic Asthma: Pathophysiology and Therapeutic Horizons

Asthma is a prevalent chronic non-communicable disease, affecting approximately 300 million people worldwide. It is characterized by significant airway inflammation, hyperresponsiveness, obstruction, and remodeling. Eosinophilic asthma, a subtype of asthma, involves the accumulation of eosinophils in the airways. These eosinophils release mediators and cytokines, contributing to severe airway inflammation and tissue damage. Emerging evidence suggests that targeting eosinophils could reduce airway remodeling and slow the progression of asthma. To achieve this, it is essential to understand the immunopathology of asthma, identify specific eosinophil-associated biomarkers, and categorize patients more accurately based on the clinical characteristics (phenotypes) and underlying pathobiological mechanisms (endotypes). This review delves into the role of eosinophils in exacerbating severe asthma, exploring various phenotypes and endotypes, as well as biomarkers. It also examines the current and emerging biological agents that target eosinophils in eosinophilic asthma. By focusing on these aspects, both researchers and clinicians can advance the development of targeted therapies to combat eosinophilic pathology in severe asthma.

Exhaled Nitric Oxide and Olfactory Dysfunction in Patients with Asthma: Association with Chronic Rhinosinusitis

Objectives: Olfactory dysfunction is a clinical sign that is important to detect with coexistent upper airway comorbidities in patients with asthma. This study aimed to investigate the etiology of olfactory dysfunction in patients with asthma and the relationship between fractional exhaled nitric oxide (FeNO) levels. Materials and Methods: This study included 47 asthma patients who were evaluated for olfactory dysfunction at Hiroshima University Hospital between 2012 and 2020. The etiologies of olfactory dysfunction were evaluated, and they were classified according to the FeNO levels of patients with asthma. Results: Olfactory dysfunction was observed in 30 patients with asthma, with chronic rhinosinusitis (77%) being the most prevalent etiology. Eosinophilic chronic rhinosinusitis (ECRS) was the most prevalent etiology of olfactory dysfunction in asthma patients with high FeNO levels (≥25 ppb), while non-eosinophilic chronic rhinosinusitis (NCRS) was the most prevalent etiology in asthma patients with low FeNO levels (<25 ppb). Additionally, the prevalence of ECRS was significantly higher in asthma patients with olfactory dysfunction and high FeNO levels (74%) than in those with either high FeNO levels or olfactory dysfunction and those with low FeNO levels and no olfactory dysfunction (12% and 9%, respectively). Conclusions: We found that ECRS was the predominant cause of olfactory dysfunction in patients with high FeNO levels, while NCRS was more common in those with low FeNO levels. The present study showed that both ECRS and NCRS are common etiologies of olfactory dysfunction in patients with asthma. Additionally, this study supports the link between upper and lower airway inflammation in patients with asthma complicated with olfactory dysfunction.

Clinical Potential of Eosinophil-Derived Neurotoxin in Asthma Management

The assessment and management of patients with asthma is challenging because of the complexity of the underlying inflammatory mechanisms and heterogeneity of their clinical presentation. Optimizing disease management requires therapy individualization that should rely on reliable biomarkers to unravel the phenotypes and endotypes of asthma. The secretory activity and turnover of eosinophils, as assessed by measuring eosinophil-derived proteins, may provide an accurate and complementary tool that mirrors the eosinophil activation status. Emerging evidence suggests that eosinophil-derived neurotoxin has considerable potential as a precision medicine biomarker. In this review, we explore the suitability of eosinophil-derived neurotoxin as a biomarker in asthma management, with particular emphasis on its clinical significance in the management of both pediatric and adult populations.

Interval change in fractional exhaled nitric oxide (FENO) reflects short-term change in adherence following electronic inhaler reminders

BACKGROUND

In asthma, suppression of fractional exhaled nitric oxide (FENO) is a marker of adherence in the short-term. The usefulness of FENO to indicate change in adherence in the longer term is unknown. The aims of this study were to determine the relationship between changes in adherence and corresponding changes in FENO over short (1 week) and long-term (3 month) periods.

METHODS

After establishing initial ICS adherence using electronic inhaler monitor (EIM) devices, reminders were switched on for 1 week ('short-term') to optimize adherence. Reminders were then switched off and patients followed up after 3 months ('long-term'). FENO was measured at the start and end of each period. Using linear regression, we analyzed change in FENO in relation to change in adherence.

RESULTS

Forty-two patients contributed complete data for analysis. In the short-term, change in adherence was independently associated with change in FENO (β = -0.36, p = 0.036) even after adjusting for initial adherence and ICS dose. The higher the initial FENO, the greater the decline in FENO with improved adherence. This relationship between change in adherence and change in FENO was not observed in the long-term.

CONCLUSION

Change in adherence over 1 week following the use of EIM reminders independently predicted change in FENO. This relationship was not maintained at 3 months.

Upper airway disease diagnosis as a predictive biomarker of therapeutic response to biologics in severe asthma

Asthma is a heterogeneous disease sharing airway instability but with different biology, risk factors, and response-to-therapy patterns. Biologics have revolutionized the one-size-fits-to-all approach to personalized medicine in severe asthma (SA), which relies on the identification of biomarkers that define distinct endotypes. Thus, blood eosinophils and, to some extent, exhaled nitric oxide (FeNO) can predict the response to approved anti-type 2 (T2) biologics (anti-IgE, anti-IL-5, and anti-IL-4R alpha), whereas age at onset and comorbidities such as anxiety/depression, obesity, reflux, and upper airway disease (UAD) also influence therapeutic responses in SA. In this article, focusing on the predictive value of biomarkers for the therapeutic response to biologics in SA, we first summarize the level of prediction achieved by T2 biomarkers (blood eosinophils, FeNO) and then review whether data support the predictive value of upper airway diagnosis on such outcomes. Post hoc analysis of most studies with T2 biologics suggests that chronic rhinosinusitis with nasal polyps (CRSwNP) and, to a lower extent, allergic rhinitis may help in predicting clinical response. Considering that T2 biologics are now also approved for the treatment of severe CRSwNP, diagnosis of upper airway disease is a key step in determining eligibility for such therapy.

Eosinophilic Asthma, Phenotypes-Endotypes and Current Biomarkers of Choice

Asthma phenotyping and endotyping are constantly evolving. Currently, several biologic agents have been developed towards a personalized approach to asthma management. This review will focus on different eosinophilic phenotypes and Th2-associated endotypes with eosinophilic inflammation. Additionally, airway remodeling is analyzed as a key feature of asthmatic eosinophilic endotypes. In addition, evidence of biomarkers is examined with a predictive value to identify patients with severe, uncontrolled asthma who may benefit from new treatment options. Finally, there will be a discussion on the results from clinical trials regarding severe eosinophilic asthma and how the inhibition of the eosinophilic pathway by targeted treatments has led to the reduction of recurrent exacerbations.

2021 Brazilian Thoracic Association recommendations for the management of severe asthma

Advances in the understanding that severe asthma is a complex and heterogeneous disease and in the knowledge of the pathophysiology of asthma, with the identification of different phenotypes and endotypes, have allowed new approaches for the diagnosis and characterization of the disease and have resulted in relevant changes in pharmacological management. In this context, the definition of severe asthma has been established, being differentiated from difficult-to-control asthma. These recommendations address this topic and review advances in phenotyping, use of biomarkers, and new treatments for severe asthma. Emphasis is given to topics regarding personalized management of the patient and selection of biologicals, as well as the importance of evaluating the response to treatment. These recommendations apply to adults and children with severe asthma and are targeted at physicians involved in asthma treatment. A panel of 17 Brazilian pulmonologists was invited to review recent evidence on the diagnosis and management of severe asthma, adapting it to the Brazilian reality. Each of the experts was responsible for reviewing a topic or question relevant to the topic. In a second phase, four experts discussed and structured the texts produced, and, in the last phase, all experts reviewed and approved the present manuscript and its recommendations.

Use of Fractional Exhaled Nitric Oxide to Guide the Treatment of Asthma: An Official American Thoracic Society Clinical Practice Guideline

Background: The fractional exhaled nitric oxide (FE_NO) test is a point-of-care test that is used in the assessment of asthma.

Objective: To provide evidence-based clinical guidance on whether FE_NO testing is indicated to optimize asthma treatment in patients with asthma in whom treatment is being considered.

Methods: An international, multidisciplinary panel of experts was convened to form a consensus document regarding a single question relevant to the use of FE_NO. The question was selected from three potential questions based on the greatest perceived impact on clinical practice and the unmet need for evidence-based answers related to this question. The panel performed systematic reviews of published randomized controlled trials between 2004 and 2019 and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) evidence-to-decision framework to develop recommendations. All panel members evaluated and approved the recommendations.

Main Results: After considering the overall low quality of the evidence, the panel made a conditional recommendation for FE_NO-based care. In patients with asthma in whom treatment is being considered, we suggest that FE_NO is beneficial and should be used in addition to usual care. This judgment is based on a balance of effects that probably favors the intervention; the moderate costs and availability of resources, which probably favors the intervention; and the perceived acceptability and feasibility of the intervention in daily practice.

Conclusions: Clinicians should consider this recommendation to measure FE_NO in patients with asthma in whom treatment is being considered based on current best available evidence.

Using FeNO Measurement in Clinical Asthma Management

Asthma is a common and heterogeneous disease, characterised by lower airway inflammation and airflow limitation. Critical factors in asthma management include establishing an accurate diagnosis and ensuring appropriate selection and dosage of anti-inflammatory therapies. The majority of asthma patients exhibit type 2 (T2) inflammation, with increased interleukin (IL)-4, IL-5, and IL-13 signalling, often with associated eosinophilia. Identifying lower airway eosinophilia with sputum induction improves asthma outcomes, but is time consuming and costly. Increased T2-inflammation leads to upregulation of nitric oxide (NO) release into the airway, with increasing fractional exhaled NO (FeNO) reflecting greater T2-inflammation. FeNO can be easily and quickly measured in the clinic, offering a point of care surrogate measure of the degree of lower airway inflammation. FeNO testing can be used to help confirm an asthma diagnosis, to guide inhaled corticosteroid therapy, to assess adherence to treatment, and to aid selection of appropriate biologic therapy. However, FeNO levels may also be influenced by a variety of intrinsic and extrinsic factors other than asthma, including nasal polyposis and cigarette smoking, and must be interpreted in the broader clinical context rather than viewed in isolation. This review discusses the clinical application of FeNO measurement in asthma care, from diagnosis to treatment selection, and describes its place in current international expert guidelines.

Serum 14-3-3β protein: a new biomarker in asthmatic patients with acute exacerbation in an observational study

Background

The determination of systemic inflammatory markers is one of the important directions to study the pathogenesis of asthma and improve the diagnosis of asthma. Current studies have found that the 14-3-3 protein family subtypes interact with target proteins to participate in the pathogenesis of a variety of immune inflammatory diseases. However, studies on serum tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein β (14-3-3β) in asthma are scarce. This study aimed to assess the clinical significance of 14-3-3β in asthmatic patients.

Methods

We recruited 54 asthmatic patients with acute exacerbation and 50 asthmatic patients with chronic persistent. The normal control group included 54 healthy individuals. Clinical characteristics, clinical indicators [fractional expiratory nitric oxide (FeNO), eosinophil count, forced vital capacity (FVC), percent of predicted FVC (FVC% predicted), forced expiratory volume in one second (FEV1), percent of predicted FEV1 (FEV1% predicted), the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and serum 14-3-3β levels were measured to compare among each group. Spearman’s rank correlation coefficient was used to evaluate the correlation between 14-3-3β and clinical indicators. Finally, Receiver-operating characteristic (ROC) curves analysis was used to determine the sensitivity and specificity of 14-3-3β.

Results

Our results showed that median (interquartile range) of serum 14-3-3β concentration (ng/mL) in acute exacerbation group of asthma (41.18 [33.06–51.76]) was much higher than that in normal control group (24.99 [17.43–29.91]; P < 0.001) and chronic persistent group of asthma (25.88 [21.03–34.55]; P < 0.001). Spearman’s correlation coefficient shows that the serum 14-3-3β level was positively correlated with FeNO (r = − 0.292, P = 0.032) and peripheral blood eosinophil count (r = 0.328, P = 0.016), and was negatively related to FEV1/FVC (r = − 0.293, P = 0.031) in the acute exacerbation group of asthma. At the same time, the serum 14-3-3β level was also negatively associated with FEV1 (r = − 0.297, P = 0.036) in the chronic persistent group of asthma. ROC curve analysis comparing acute exacerbation group of asthma with normal control group demonstrated a significant (P < 0.001) AUC of 0.90 (95% CI 0.85–0.96).

Conclusion

The serum 14-3-3β protein may become a potential biomarker in asthmatic patients with acute exacerbation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00608-4.

Recent Insights into the Management of Inflammation in Asthma

The present prevailing inflammatory paradigm in asthma is of T2-high inflammation orchestrated by key inflammatory cells like Type 2 helper lymphocytes, innate lymphoid cells group 2 and associated cytokines. Eosinophils are key components of this T2 inflammatory pathway and have become key therapeutic targets. Real-world evidence on the predominant T2-high nature of severe asthma is emerging. Various inflammatory biomarkers have been adopted in clinical practice to aid asthma characterization including airway measures such as bronchoscopic biopsy and lavage, induced sputum analysis, and fractional exhaled nitric oxide. Blood measures like eosinophil counts have also gained widespread usage and multicomponent algorithms combining different parameters are now appearing. There is also growing interest in potential future biomarkers including exhaled volatile organic compounds, micro RNAs and urinary biomarkers. Additionally, there is a growing realisation that asthma is a heterogeneous state with numerous phenotypes and associated treatable traits. These may show particular inflammatory patterns and merit-specific management approaches that could improve asthma patient outcomes. Inhaled corticosteroids (ICS) remain the mainstay of asthma management but their use earlier in the course of disease is being advocated. Recent evidence suggests potential roles for ICS in combination with long-acting beta-agonists (LABA) for as needed use in mild asthma whilst maintenance and reliever therapy regimes have gained widespread acceptance. Other anti-inflammatory strategies including ultra-fine particle ICS, leukotriene receptor antagonists and macrolide antibiotics may show efficacy in particular phenotypes too. Monoclonal antibody biologic therapies have recently entered clinical practice with significant impacts on asthma outcomes. Understanding of the efficacy and use of those agents is becoming clearer with a growing body of real-world evidence as is their potential applicability to other treatable comorbid traits. In conclusion, the evolving understanding of T2 driven inflammation alongside a treatable traits disease model is enhancing therapeutic approaches to address inflammation in asthma.

Baseline FeNO as a prognostic biomarker for subsequent severe asthma exacerbations in patients with uncontrolled, moderate-to-severe asthma receiving placebo in the LIBERTY ASTHMA QUEST study: a post-hoc analysis

BACKGROUND

Fractional exhaled nitric oxide (FeNO) has potential as a prognostic biomarker in asthma, but its prognostic value among other recognised indicators is unclear. We assessed the added prognostic value of baseline FeNO to blood eosinophil count and prior severe asthma exacerbations for subsequent exacerbations.

METHODS

In this post-hoc analysis of the 52-week, double-blind, phase 3 LIBERTY ASTHMA QUEST study, we identified 620 patients with moderate-to-severe asthma who were randomly assigned to placebo; had uncontrolled asthma with inhaled glucocorticoids plus up to two controllers; one or more exacerbations in the previous year; FEV₁ percent predicted 40-80%; FEV₁ reversibility of 12% or higher and 200 mL; Asthma Control Questionnaire (ACQ-5) score of 1·5 or higher; and complete data on baseline type 2 biomarkers (FeNO, eosinophils, and total IgE) with no baseline minimum requirement. Annualised severe exacerbation rate was assessed by baseline FeNO (<25 ppb, ≥25 to <50 ppb, ≥50 ppb; negative binomial model) and cross-classified by baseline blood eosinophils (<150 cells per μL, ≥150 to <300 cells per μL, ≥300 cells per μL) and prior exacerbations (one, two or more), all adjusted for baseline ACQ-5, postbronchodilator FEV₁, and other clinical characteristics. Post-hoc analyses were done in the intention-to-treat population. The LIBERTY ASTHMA QUEST STUDY is registered on ClinicalTrials.gov, NCT02414854, and is complete.

FINDINGS

Patients with baseline FeNO of 50 ppb or higher (n=144) had a 1·54-times higher exacerbation rate than patients with FeNO of less than 25 ppb (n=291; relative risk 1·54 [95% CI 1·11-2·14]; p=0·0097). Patients with baseline FeNO of 25 to <50 ppb (n=185) had a 1·33-times higher exacerbation rate than patients with FeNO of less than 25 ppb (1·33 [0·99-1·78]; p=0·0572). Patients with baseline FeNO of 25 ppb or higher, a blood eosinophil count of 150 cells per μL or higher, and two or more prior exacerbations (n=157) had an exacerbation rate 3·62-times higher than patients with FeNO of less than 25 ppb, a blood eosinophil count of less than 150 cells per μL, and one prior exacerbation (n=116; 3·62 [1·67-7·81]; p=0·0011).

INTERPRETATION

In uncontrolled, moderate-to-severe asthma, higher baseline FeNO levels were associated with greater risk of severe asthma exacerbations, particularly in combination with elevated eosinophil count and prior exacerbations, supporting the added value of FeNO as a prognostic biomarker. Further research is needed to confirm FeNO as an independent predictor for asthma exacerbations.

FUNDING

Sanofi and Regeneron Pharmaceuticals.

Biomarkers in Different Asthma Phenotypes

Asthma is the most common respiratory disease. It has multiple phenotypes thatcan be partially differentiated by measuring the disease’s specific characteristics—biomarkers. The pathogenetic mechanisms are complex, and it is still a challenge to choose suitable biomarkers to adequately stratify patients, which became especially important with the introduction of biologicals in asthma treatment. Usage of biomarkers and an understanding of the underlying pathobiological mechanisms lead to the definition of endotypes. Asthma can be broadly divided into two endotypes, T2-high and T2-low. The right combination of various biomarkers in different phenotypes is under investigation, hoping to help researchers and clinicians in better disease evaluation since theindividual approach and personalized medicine are imperative. Multiple biomarkers are superior to a single biomarker.

Chronic eosinophilic pneumonitis due to the inhalation of aerosolized face lotion: A case report

RATIONALE

Inhalation of toxic agents can induce eosinophilic pneumonia. However, only a few case reports demonstrate that exposure to materials can induce chronic eosinophilic pneumonia (CEP). Here, we describe a rare case of CEP with mild alveolar hemorrhage due to the inhalation of aerosols from face lotion. This is the first report of eosinophilic pneumonia caused by face lotion exposure.

PATIENT CONCERNS

A 39-year-old woman was admitted to our hospital with cough and dyspnea for 2 months, which coincided when she started to use a new aerosolized face lotion. Laboratory findings showed high blood eosinophil levels, and chest computed tomography (CT) scans revealed bilateral peripheral consolidation and ground-glass opacity mainly in the left upper lobe. She underwent flexible bronchoscopy. Eosinophils in bronchoalveolar lavage fluid (BALF) were slightly elevated, and the gross appearance of BALF was bloody. The histological examination of the transbronchial lung biopsy showed infiltration of eosinophils and macrophages in alveolar septa with edema and without vasculitis and granuloma formation; a small number of hemosiderin-laden macrophages were also observed. An inhalation challenge test involving the face lotion was performed. Six hours after the test, the blood test showed an increased white blood cell (WBC) count, and chest radiography showed slight exacerbation. Forced vital capacity decreased the following day.

DIAGNOSIS

According to histological analysis and positive result of an inhalation challenge test, she was diagnosed with CEP with mild alveolar hemorrhage due to inhalation of aerosols from the face lotion.

INTERVENTIONS AND OUTCOMES

She gradually improved without medication after stopping the use of face lotion.

LESSONS

To the best of our knowledge, this is the first report of CEP with mild alveolar hemorrhage due to the inhalation of face lotion. Various inhaled agents, such as face lotion, can induce CEP in rare cases.

Phenotype-Guided Asthma Therapy: An Alternative Approach to Guidelines

Despite recent advances in therapy, a substantial proportion of asthmatics remain not well controlled. The classical stepwise approach to pharmacological therapy in adult asthma recommends that treatment is progressively stepped up by increasing the inhaled corticosteroid (ICS) dose or by adding another controller medication- to achieve symptom control and reduce the risk of exacerbations, and stepped down after a period of control. In general, asthma guideline recommendations do not reflect that there are significant differences between ICS in terms of potency. Moreover, they do not consider efficacy and safety separately, incorrectly assuming that "low" and "high" dose categories inevitably correspond with low and high risk of systemic effects. Another point of criticism is the fact that guidelines do not take into account the inflammatory profile of the patient, although substantial groups of patients with mild and moderate asthma have little evidence of "T2-high" inflammation, and by extension are likely to show a poor response to ICS treatment. On the other hand, the latest version of the Global Initiative for Asthma (GINA) equally recommends regular ICS and ICS/formoterol as needed to prevent exacerbations in step 2 patients, without taking into consideration that the therapeutic objectives (exacerbations, symptoms) may differ between individual patients and that different goals may warrant distinct treatment strategies. In this review, we bring to the table several controversial issues concerning asthma treatment and suggest an alternative proposal that takes into consideration the potential side effects of high ICS doses, the patient's inflammatory profile and the therapeutic goals to be achieved.

Asthma phenotypes and endotypes in childhood

Asthma is a very heterogeneous disease and since early childhood many classifications have been proposed according to phenotype and endotype. The phenotype includes the clinical features of asthma such as age of onset, triggers, comorbidities, response to treatment and evolution over time. The endotype is more difficult to define, includes the underlying immunopathological mechanisms of the disease and requires reliable biomarkers. A deep knowledge of phenotype and endotype of the patient may guide a tailored therapeutic approach. In this review the main phenotypes and endotypes of asthma acknowledged in children will be discussed.

Biomarkers of Bronchial Asthma

Asthma is a complex disease with a variable course. Efforts to identify biomarkers to predict asthma severity, the course of disease and response to treatment have not been very successful so far. Biomarker research has expanded greatly with the advancement of molecular research techniques. An ideal biomarker should be suitable to identify the disease as well the specific endotype/phenotype, useful in the monitoring of the disease and to determine the prognosis, easily to obtain with minimum discomfort or risk to the patient. An ideal biomarker should be suitable to identify the disease as well the specific endotype/phenotype, useful in the monitoring of the disease and to determine the prognosis, easily to obtain with minimum discomfort or risk to the patient - exhaled breath analysis, blood cells and serum biomarkers, sputum cells and mediators and urine metabolites could be potential biomarkers of asthma bronchiale. Unfortunately, at the moment, an ideal biomarker doesn't exist and the overlap between the biomarkers is a reality. Using panels of biomarkers could improve probably the identification of asthma endotypes in the era of precision medicine.

Automated cell differential count in sputum is feasible and comparable to manual cell count in identifying eosinophilia

INTRODUCTION

Cell differential count (CDC) of induced sputum is considered the gold standard for inflammatory phenotyping of asthma but is not implemented in routine care due to its heavy time- and staff demands. Digital Cell Morphology is a technique where digital images of cells are captured and presented preclassified as white blood cells (neutrophils, eosinophils, lymphocytes, macrophages, and unidentified) and nonwhite blood cells for review. With this study, we wanted to assess the accuracy of an automated CDC in identifying the key inflammatory cells in induced sputum.

METHODS

Sputum from 50 patients with asthma was collected and processed using the standard processing protocol with one drop 20% albumin added to hinder cell smudging. Each slide was counted automatically using the CellaVision DM96 and manually by an experienced lab technician. Sputum was classified as eosinophilic or neutrophilic using 3% and 61% cutoffs, respectively.

RESULTS

We found a good agreement using intraclass correlation for all target cells, despite significant differences in the cell count rate. The automated CDC had a sensitivity of 65%, a specificity of 93%, and a kappa-coefficient of 0.61 for identification of sputum eosinophilia. In contrast, the automated CDC had a sensitivity of 29%, a specificity of 100%, and a kappa-coefficient of 0.23 for identification of sputum neutrophilia.

CONCLUSION

Automated- and manual cell counts of sputum agree with regards to the key inflammatory cells. The automated cell count had a modest sensitivity but a high specificity for the identification of both neutrophil and eosinophil asthma.

Applying personalized medicine to adult severe asthma

Background: Severe asthma is a heterogeneous disease that consists of various phenotypes driven by different pathways. Associated with significant morbidity, an important negative impact on the quality of life of patients, and increased health care costs, severe asthma represents a challenge for the clinician. With the introduction of various antibodies that target type 2 inflammation (T2) pathways, severe asthma therapy is gradually moving to a personalized medicine approach. Objective: The purpose of this review was to emphasize the important role of personalized medicine in adult severe asthma management. Methods: An extensive research was conducted in medical literature data bases by applying terms such as "severe asthma" associated with "structured approach," "comorbidities," "biomarkers," "phenotypes/endotypes," and "biologic therapies." Results: The management of severe asthma starts with a structured approach to confirm the diagnosis, assess the adherence to medications and identify confounding factors and comorbidities. The definition of phenotypes or endotypes (phenotypes defined by mechanisms and identified through biomarkers) is an important step toward the use of personalized medicine in asthma. Severe allergic and nonallergic eosinophilic asthma are two defined T2 phenotypes for which there are efficacious targeted biologic therapies currently available. Non-T2 phenotype remains to be characterized, and less efficient target therapy exists. Conclusion: Despite important progress in applying personalized medicine to severe asthma, especially in T2 inflammatory phenotypes, future research is needed to find valid biomarkers predictive for the response to available biologic therapies to develop more effective therapies in non-T2 phenotype.

Airway Redox Homeostasis and Inflammation Gone Awry: From Molecular Pathogenesis to Emerging Therapeutics in Respiratory Pathology

As aerobic organisms, we are continuously and throughout our lifetime subjected to an oxidizing atmosphere and, most often, to environmental threats. The lung is the internal organ most highly exposed to this milieu. Therefore, it has evolved to confront both oxidative stress induced by reactive oxygen species (ROS) and a variety of pollutants, pathogens, and allergens that promote inflammation and can harm the airways to different degrees. Indeed, an excess of ROS, generated intrinsically or from external sources, can imprint direct damage to key structural cell components (nucleic acids, sugars, lipids, and proteins) and indirectly perturb ROS-mediated signaling in lung epithelia, impairing its homeostasis. These early events complemented with efficient recognition of pathogen- or damage-associated recognition patterns by the airway resident cells alert the immune system, which mounts an inflammatory response to remove the hazards, including collateral dead cells and cellular debris, in an attempt to return to homeostatic conditions. Thus, any major or chronic dysregulation of the redox balance, the air-liquid interface, or defects in epithelial proteins impairing mucociliary clearance or other defense systems may lead to airway damage. Here, we review our understanding of the key role of oxidative stress and inflammation in respiratory pathology, and extensively report current and future trends in antioxidant and anti-inflammatory treatments focusing on the following major acute and chronic lung diseases: acute lung injury/respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis.

Asthma in Competitive Cross-Country Skiers: A Systematic Review and Meta-analysis

INTRODUCTION

In cross-country skiing, the repetitive ventilation of large amounts of cold and dry air strains the airways. The aim of this systematic review was to establish an overview of the current literature on asthma in cross-country skiers, biathletes and ski-orienteers.

METHODS

Six databases were searched on August 29, 2019. The search yielded 2161 articles. Thirty articles fulfilled the search criteria and were pooled together for a qualitative synthesis. Eight articles were included in the meta-analysis on the prevalence of asthma and the use of asthma medication.

RESULTS

According to the meta-analysis, the prevalence of self-reported physician-diagnosed asthma in skiers was 21% (95% CI 14-28%). The onset age of asthma was higher in skiers than in non-skiers with asthma. The prevalence of asthma medication use was on average 23% (CI 95% 19-26%). Several studies reported that asthma was underdiagnosed in skiers, as previously healthy skiers without a prior asthma diagnosis or medication use were frequently found to fulfill diagnostic criteria for asthma according to lung function tests. Studies using bronchial biopsy demonstrated that eosinophilic asthma is not detected in skiers with asthma as often as it is in non-skiers with asthma and that there are signs of airway inflammation even in non-asthmatic skiers.

CONCLUSION

Our findings suggest that the accuracy and coverage of diagnosing asthma in skiers has improved over the recent decades. However, the optimal treatment and natural course of asthma in this population remain unclear. Future research should investigate how the intensity of training, airway infections and their treatment affect the development of asthma among skiers.

PRD REGISTRATION NUMBER

CRD42017070940.

Breathomics in Asthmatic Children Treated with Inhaled Corticosteroids

BACKGROUND

"breathomics" enables indirect analysis of metabolic patterns underlying a respiratory disease. In this study, we analyze exhaled breath condensate (EBC) in asthmatic children before (T0) and after (T1) a three-week course of inhaled beclomethasone dipropionate (BDP).

METHODS

we recruited steroid-naive asthmatic children for whom inhaled steroids were indicated and healthy children, evaluating asthma control, spirometry and EBC (in asthmatics at T0 and T1). A liquid-chromatography-mass-spectrometry untargeted analysis was applied to EBC and a mass spectrometry-based target analysis to urine samples.

RESULTS

metabolomic analysis discriminated asthmatic (n = 26) from healthy children (n = 16) at T0 and T1, discovering 108 and 65 features relevant for the discrimination, respectively. Searching metabolomics databases, seven putative biomarkers with a plausible role in asthma biochemical-metabolic processes were found. After BDP treatment, asthmatic children, in the face of an improved asthma control (p < 0.001) and lung function (p = 0.01), showed neither changes in EBC metabolomic profile nor in urinary endogenous steroid profile.

CONCLUSIONS

"breathomics" can discriminate asthmatic from healthy children, with prostaglandin, fatty acid and glycerophospholipid as putative markers. The three-week course of BDP-in spite of a significant clinical improvement-was not associated with changes in EBC metabolic arrangement and urinary steroid profile.

A Proposed Approach to Chronic Airway Disease (CAD) Using Therapeutic Goals and Treatable Traits: A Look to the Future

Chronic airflow obstruction affects a wide range of airway diseases, the most frequent of which are asthma, COPD, and bronchiectasis; they are clearly identifiable in their extremes, but quite frequently overlap in some of their pathophysiological and clinical characteristics. This has generated the description of new mixed or overlapping disease phenotypes with no clear biological grounds. In this special article, a group of experts provides their perspective and proposes approaching the treatment of chronic airway disease (CAD) through the identification of a series of therapeutic goals (TG) linked to treatable traits (TT) - understood as clinical, physiological, or biological characteristics that are quantifiable using biomarkers. This therapeutic approach needs validating in a clinical trial with the strategy of identification of TG and treatment according to TT for each patient independently of their prior diagnosis.

Are type-2 biomarkers of any help in asthma diagnosis?

T2 biomarkers lack the accuracy to make an asthma diagnosis in patients with suggestive symptoms https://bit.ly/3hYnnHu.

Measuring inflammation in paediatric severe asthma: biomarkers in clinical practice

Severe asthma in children is a highly heterogeneous disorder, encompassing different clinical characteristics (phenotypes) and immunopathological pathways (endotypes). Research is focusing on the identification of noninvasive biomarkers able to predict treatment response and assist in designing personalised therapies for severe asthma. Blood and sputum eosinophils, serum IgE and exhaled nitric oxide fraction mostly reflect type 2 airway inflammation in children. However, in the absence of available point-of-care biomarkers, the diagnosis of non-type 2 asthma is still reached by exclusion. In this review, we present the most recent evidence on biomarkers for severe asthma and discuss their implementation in clinical practice. We address the methods for guiding treatment decisions and patient identification, focusing on the paediatric age group.

Noninvasive biomarkers should be integrated with clinical findings to assist in diagnosing and guiding personalised therapies for severe asthma in childrenhttp://bit.ly/2JPvKFV

Predictive factors of response to inhaled corticosteroids in newly diagnosed asthma: A real-world observational study

BACKGROUND

Asthma is characterized by chronic airway inflammation, and inhaled corticosteroids (ICSs) have been recommended as first-line treatment. However, response to ICS treatment is various, and the prediction of response to ICSs is still difficult, especially in individuals with newly diagnosed asthma.

OBJECTIVE

To assess the clinical factors and biomarkers associated with response to ICSs in newly diagnosed asthma.

METHODS

A total of 150 ICS-naive patients with newly diagnosed asthma in the allergy clinic of a single tertiary hospital in Korea from January 2014 to January 2019 were included in this study. All patients initially received moderate-dose ICSs and were treated for more than 1 year. We compared the clinical characteristics and parameters between patients with and without acute exacerbation (AE) during the study period.

RESULTS

In this study, 99 patients had no AE (stable asthma group), and 51 patients presented with more than 1 AE (unstable asthma group). The mean (SD) blood eosinophil count (635.7 [780.3] × 10³/μL vs 373.4 [266.8] × 10³/μL, P = .003) and sputum eosinophil count (15.2% [23.9%] vs 8.3% [15.4%], P = .051) were higher and the sputum neutrophil count (42.9% [35.1%] vs 61.3% [35.1%], P = .057) was lower in the stable asthma group than in the unstable asthma group.

CONCLUSION

High blood and sputum eosinophil counts can predict a good response to ICS treatment in terms of prevention of AE in individuals with newly diagnosed asthma. The sputum neutrophil count may be an effective predictor of response to ICSs, even though additional studies must be conducted.

Serum Eosinophil-Derived Neurotoxin Better Reflect Asthma Control Status Than Blood Eosinophil Counts

BACKGROUND

Although several biomarkers have been proposed for eosinophilic asthma, biomarkers for reflecting asthma control status remain controversial. Eosinophil-derived neurotoxin (EDN), a degranulated eosinophil protein, is an emerging biomarker in asthmatic patients.

OBJECTIVE

This study analyzed serum EDN concentrations in asthmatics and compared its performance with that of blood eosinophil count as an indicator of asthma control status.

METHODS

We enrolled 75 uncontrolled asthmatics, 56 controlled asthmatics, and 43 healthy controls from Asan Medical Center. Serum EDN levels (ng/mL) were measured using an enzyme-linked immunosorbent assay kit. The predictability of EDN for asthma control status was analyzed by univariate and multivariable logistic regression analyses. A receiver operating characteristic (ROC) curve analysis was conducted to compare the performances of a serum EDN level and blood eosinophil count as indicators of uncontrolled asthma status.

RESULTS

The mean serum EDN level in the uncontrolled asthma group was higher than that in the controlled asthma and healthy groups (103.2 ± 60.2 vs 60.8 ± 49.7 vs 49.6 ± 28.3 ng/mL, P < .001). Serum EDN level was the significant parameter related to asthma control status in univariate and multivariable analysis (both P < .001). Serum EDN levels correlated with blood eosinophil counts (r = 0.510, P < .001). However, in the ROC analysis, serum EDN level showed a significantly better performance for predicting uncontrolled asthma status (area under the curve, 0.726 vs 0.628, P = .024).

CONCLUSIONS

Serum EDN levels significantly differed between patients with controlled and uncontrolled status in adult asthmatics. To our knowledge, this is the first study to identify EDN as a better indicator of asthma control status than blood eosinophil count.

Precision medicine in childhood asthma

PURPOSE OF REVIEW

Childhood asthma is a heterogeneous disease and many children have uncontrolled disease. Therefore an individualized approach is needed to improve asthma outcomes in children. Precision medicine using clinical characteristics, biomarkers, and the rapidly involving field of genomics and pharmacogenomics aims to achieve asthma control and reduce future risks with less side-effects in individual children with asthma.

RECENT FINDINGS

It is not yet possible to select treatment options on clinical characteristics. Novel monoclonal antibodies are efficacious in patients with severe, eosinophilic asthma. Reduced lung function growth and early decline is a prevalent finding in children with persistent asthma. Pharmacogenetic studies have identified children at risk for cortisol suppression when using inhaled corticosteroids.

SUMMARY

Clinical characteristics and simple biomarkers like eosinophils, IgE, and the fraction of exhaled nitric oxide may be used in clinical practice for a basic precision medicine approach, deciding which children will have the best chance to respond to inhaled corticosteroids and to the biologicals omalizumab and mepolizumab.Further application of pharmacogenomics and breathomics needs additional studies before they can be applied as tools for precision medicine in individual children with asthma.

Predictive value of blood eosinophils and exhaled nitric oxide in adults with mild asthma: a prespecified subgroup analysis of an open-label, parallel-group, randomised controlled trial

BACKGROUND

Whether blood eosinophil counts and exhaled nitric oxide (FeNO) are associated with important outcomes in mild asthma is unclear. In this prespecified subgroup analysis of a previously published open-label clinical trial, we aimed to assess associations between blood eosinophil counts and FeNO with outcomes and response to asthma treatment.

METHODS

In the previously reported 52-week, open-label, randomised controlled trial, people with mild asthma receiving only β agonist reliever inhalers were enrolled at one of 16 clinical trials units in New Zealand, the UK, Italy, or Australia. Eligible participants were randomly assigned (1:1:1, stratified by country), to receive inhalers to take as-needed salbutamol (two inhalations of 100 μg in a pressurised metered dose inhaler), maintenance budesonide (200 μg twice per day by inhaler) plus as-needed salbutamol (two inhalations of 100 μg), or as-needed budesonide-formoterol (one inhalation of 200 μg budesonide and 6μg formoterol by inhaler). The primary outcome was the annual rates of asthma exacerbations per patient, and in this prespecified subgroup analysis, we assessed whether annual exacerbation rates in each treatment group were significantly different depending on levels of blood eosinophil count, FeNO, or a composite score of both. Analyses were done for patients with available biomarker measurements The study was registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12615000999538.

FINDINGS

675 participants were enrolled between March 17, 2016, and Aug 29, 2017, of whom 656 had results for blood eosinophil analysis and 668 had results for FeNO. Of the patients who received as-needed salbutamol, the proportion of patients having a severe exacerbation increased progressively with increasing blood eosinophil count (two [4%] of 49 participants with <0·15 × 10⁹/L, six [6%] of 93 with 0·15 to <0·3 × 10⁹/L, and 15 [19%] of 77 with ≥0·3 × 10⁹/L; p=0·014). There were no significant interactions between blood eosinophil count or FeNO level and the effect of as-needed budesonide-formoterol compared with as-needed salbutamol for either exacerbations or severe exacerbations. However, there were significant interactions between blood eosinophil count subgroups and the effect of maintenance budesonide plus as-needed salbutamol compared with as-needed salbutamol, both for exacerbations (p=0·0006) and severe exacerbations (p=0·0007). Maintenance budesonide plus as-needed salbutamol was more effective than as-needed salbutamol in patients with blood eosinophil counts of 0·3 × 10⁹/L or more, both for exacerbations (rate ratio 0·13 [95% CI 0·05-0·33]) and severe exacerbations (risk odds ratio 0·11 [0·03-0·45]). This difference was not seen for blood eosinophil counts of less than 0·15 × 10⁹/L (1·15 [0·51-1·28] for exacerbations and 5·72 [0·97-33·60] for severe exacerbations). There was no consistent interaction between treatment response and FeNO or the composite score.

INTERPRETATION

In patients with mild asthma, the effects of as-needed budesonide-formoterol on exacerbations are independent of biomarker profile, whereas the benefits of maintenance inhaled budesonide are greater in patients with high blood eosinophil counts than in patients with low counts.

FUNDING

AstraZeneca, Health Research Council of New Zealand.

Fractional Exhaled Nitric Oxide (FENO) in the management of asthma: a position paper of the Italian Respiratory Society (SIP/IRS) and Italian Society of Allergy, Asthma and Clinical Immunology (SIAAIC)

Asthma prevalence in Italy is on the rise and is estimated to be over 6% of the general population. The diagnosis of asthma can be challenging and elusive, especially in children and the last two decades has brought evidences that asthma is not a single disease but consists of various phenotypes. Symptoms can be underestimated by the patient or underreported to the clinician and physical signs can be scanty. Usual objective measures, like spirometry, are necessary but sometimes not significant. Despite proper treatment, asthma can be a very severe condition (even leading to death), however new drugs have recently become available which can be very effective in its control. Since asthma is currently thought to be caused by inflammation, a direct measure of the latter can be of paramount importance. For this purpose, the measurement of Fractional Exhaled Nitric Oxide (FE_NO) has been used since the early years of the current century as a non-invasive, easy-to-assess tool useful for diagnosing and managing asthma. This SIP-IRS/SIAAIC Position Paper is a narrative review which summarizes the evidence behind the usefulness of FE_NO in the diagnosis, management and phenotypization of asthma.

How can we minimise the use of regular oral corticosteroids in asthma?

Options to achieve oral corticosteroid (OCS)-sparing have been triggering increasing interest since the 1970s because of the side-effects of OCSs, and this has now become achievable with biologics. The Société de Pneumologie de Langue Française workshop on OCSs aimed to conduct a comprehensive review of the basics for OCS use in asthma and issue key research questions. Pharmacology and definition of regular use were reviewed by the first working group (WG1). WG2 examined whether regular OCS use is associated with T2 endotype. WG3 reported on the specificities of the paediatric area. Key “research statement proposals” were suggested by WG4. It was found that the benefits of regular OCS use in asthma outside episodes of exacerbations are poorly supported by the existing evidence. However, complete OCS elimination couldn’t be achieved in any available studies for all patients and the panel felt that it was too early to conclude that regular OCS use could be declared criminal. Repeated or prolonged need for OCS beyond 1 g·year⁻¹ should indicate the need for referral to secondary/tertiary care. A strategic sequential plan aiming at reducing overall exposure to OCS in severe asthma was then held as a conclusion of the workshop.

A yearly cumulative OCS dose above 1 g should be considered unacceptable in severe asthma and should make the case for referralhttp://bit.ly/34GAYLX

Asthma and Corticosteroid Responses in Childhood and Adult Asthma

Corticosteroids are the most effective treatment for asthma; inhaled corticosteroids (ICSs) are the first-line treatment for children and adults with persistent symptoms. ICSs are associated with significant improvements in lung function. The anti-inflammatory effects of corticosteroids are mediated by both genomic and nongenomic factors. Variation in the response to corticosteroids has been observed. Patient characteristics, biomarkers, and genetic features may be used to predict response to ICSs. The existence of multiple mechanisms underlying glucocorticoid insensitivity raises the possibility that this might indeed reflect different diseases with a common phenotype.

Atopy Modifies the Association Between Inhaled Corticosteroid Use and Lung Function Decline in Patients with Asthma

BACKGROUND

Inhaled corticosteroids (ICSs) are the mainstay of asthma treatment, but response to medication is variable. Patients with allergic inflammation generally show a better short-term response to ICSs; however, studies on predictors of long-term response are few.

OBJECTIVE

To assess whether allergic sensitization can modify the association between ICS use and lung function decline over 20 years in adult asthma.

METHODS

We used data from the 3 clinical examinations of the European Community Respiratory Health Survey. We measured ICS use (no use, and use for <1.3, 1.3-8, and >8 years) and FEV₁ decline among subjects with asthma over the 2 periods between consecutive examinations. We conducted a cohort study combining data of the 2 periods (906 observations from 745 subjects) to assess whether the association between ICS use and FEV₁ decline was modified by allergic sensitization (IgE > 0.35 kU/L for any of house-dust mite, timothy grass, cat, or Cladosporium).

RESULTS

FEV₁ decline was similar for non-ICS users, as well as ICS users for less than 1.3 years, with and without allergic sensitization. However, among subjects on ICSs for a longer period, sensitization was associated with an attenuated decline (P_interaction = .006): in the group treated for more than 8 years, FEV₁ decline was on average 27 mL/y (95% CI_{Bonferroni-adjusted}, 11-42) lower for subjects with sensitization compared with nonsensitized subjects.

CONCLUSIONS

Our study suggests that biomarkers of atopy can predict a more favorable long-term response to ICSs. Randomized controlled studies are needed to confirm these findings.

What did we learn from multiple omics studies in asthma?

More than a decade has passed since the finalization of the Human Genome Project. Omics technologies made a huge leap from trendy and very expensive to routinely executed and relatively cheap assays. Simultaneously, we understood that omics is not a panacea for every problem in the area of human health and personalized medicine. Whilst in some areas of research omics showed immediate results, in other fields, including asthma, it only allowed us to identify the incredibly complicated molecular processes. Along with their possibilities, omics technologies also bring many issues connected to sample collection, analyses and interpretation. It is often impossible to separate the intrinsic imperfection of omics from asthma heterogeneity. Still, many insights and directions from applied omics were acquired-presumable phenotypic clusters of patients, plausible biomarkers and potential pathways involved. Omics technologies develop rapidly, bringing improvements also to asthma research. These improvements, together with our growing understanding of asthma subphenotypes and underlying cellular processes, will likely play a role in asthma management strategies.

The role of endogenous bromotyrosine in health and disease

Bromotyrosine is a stable by-product of eosinophil peroxidase activity, a result of eosinophil activation during an inflammatory immune response. The elevated presence of bromotyrosine in tissue, blood, and urine in medical conditions involving eosinophil activation has highlighted the potential role of bromotyrosine as a medical biomarker. This is highly beneficial in a paediatric setting as a urinary noninvasive biomarker. However, bromotyrosine and its derivatives may exert biological effects, such as protective effects in the brain and pathogenic effects in the thyroid. Understanding these pathways may yield therapeutic advancements in medicine. In this review, we summarize the existing evidence present in literature relating to bromotyrosine formation and metabolism, identify the biological actions of bromotyrosine and evaluate the feasibility of bromotyrosine as a medical biomarker.

It's Time to Start Phenotyping Our Patients with Asthma

Advances in the management of pediatric asthma, including biologics, offer practitioners the ability to tailor therapies to individual patients. However, asthma treatment guidelines have not kept up with current studies. This review explores the current literature incorporating the use of phenotyping in pediatric patients with asthma to provide precision therapy. Biomarkers can be used to more accurately predict the development of asthma, identify features that may be associated with difficult-to-control or severe asthma, and forecast response to therapies. Biomarkers and other phenotypic data can also be helpful in patients with uncontrolled, severe asthma in the selection of a biologic therapy.

Asthma progression and mortality: the role of inhaled corticosteroids

Overall, asthma mortality rates have declined dramatically in the last 30 years, due to improved diagnosis and to better treatment, particularly in the 1990s following the more widespread use of inhaled corticosteroids (ICSs). The impact of ICS on other long-term outcomes, such as lung function decline, is less certain, in part because the factors associated with these outcomes are incompletely understood. The purpose of this review is to evaluate the effect of pharmacological interventions, particularly ICS, on asthma progression and mortality. Furthermore, we review the potential mechanisms of action of pharmacotherapy on asthma progression and mortality, the effects of ICS on long-term changes in lung function, and the role of ICS in various asthma phenotypes.Overall, there is compelling evidence of the value of ICS in improving asthma control, as measured by improved symptoms, pulmonary function and reduced exacerbations. There is, however, less convincing evidence that ICS prevents the decline in pulmonary function that occurs in some, although not all, patients with asthma. Severe exacerbations are associated with a more rapid decline in pulmonary function, and by reducing the risk of severe exacerbations, it is likely that ICS will, at least partially, prevent this decline. Studies using administrative databases also support an important role for ICS in reducing asthma mortality, but the fact that asthma mortality is, fortunately, an uncommon event makes it highly improbable that this will be demonstrated in prospective trials.

Biomarkers and asthma management: analysis and potential applications

PURPOSE OF REVIEW

Asthma features a high degree of heterogeneity in both pathophysiology and therapeutic response, resulting in many asthma patients being treated inadequately. Biomarkers indicative of underlying pathological processes could be used to identify disease subtypes, determine prognosis and to predict or monitor treatment response. However, the newly identified as well as more established biomarkers have different applications and limitations.

RECENT FINDINGS

Conventional markers for type 2-high asthma, such as blood eosinophils, fraction of exhaled nitric oxide, serum IgE and periostin, feature limited sensitivity and specificity despite their significant correlations. More distinctive models have been developed by combining biomarkers and/or using omics techniques. Recently, a model with a positive predictive value of 100% for identification of type 2-high asthma based on a combination of minimally invasive biomarkers was developed.

SUMMARY

Individualisation of asthma treatment regimens on the basis of biomarkers is necessary to improve asthma control. However, the suboptimal properties of currently available conventional biomarkers limit its clinical utility. Newly identified biomarkers and models based on combinations and/or omics analysis must be validated and standardised before they can be routinely applied in clinical practice. The development of robust biomarkers will allow development of more efficacious precision medicine-based treatment approaches for asthma.

Biomarkers in asthma: state of the art

Asthma is a heterogenous disease characterized by multiple phenotypes driven by different mechanisms. The implementation of precision medicine in the management of asthma requires the identification of phenotype-specific markers measurable in biological fluids. To become useful, these biomarkers need to be quantifiable by reliable systems, reproducible in the clinical setting, easy to obtain and cost-effective. Using biomarkers to predict asthma outcomes and therapeutic response to targeted therapies has a great clinical significance, particularly in severe asthma. In the last years, significant research has been realized in the identification of valid biomarkers for asthma. This review focuses on the existent and emerging biomarkers with clinical higher applicability in the management of asthma.

Recent developments and highlights in biomarkers in allergic diseases and asthma

The potential of precision medicine in allergy and asthma has only started to be explored. A significant clarification in the pathophysiology of rhinitis, chronic rhinosinusitis, asthma, food allergy and drug hypersensitivity was made in the last decade. This improved understanding led to a better classification of the distinct phenotypes and to the discovery of new drugs such as biologicals, targeting phenotype-specific mechanisms. Nevertheless, many conditions remain poorly understood such as non-eosinophilic airway diseases or non-IgE-mediated food allergy. Moreover, there is a need to predict the response to specific therapies and the outcome of drug and food provocations. The identification of patients at risk of progression towards severity is also an unmet need in order to establish adequate preventive or therapeutic measures. The implementation of precision medicine in the clinical practice requires the identification of phenotype-specific markers measurable in biological matrices. To become useful, these biomarkers need to be quantifiable by reliable systems, and in samples obtained in an easy, rapid and cost-efficient way. In the last years, significant research resources have been put in the identification of valid biomarkers for asthma and allergic diseases. This review summarizes these recent advances with focus on the biomarkers with higher clinical applicability.

Immunoglobulin E as a Biomarker in Asthma

Asthma is a chronic disease that affects children and adults with significant morbidity and mortality. It is multifactorial, with genetic and environmental factors affecting the overall course of the disease. Both specific and total immunoglobulin (Ig)E can be used in specific phenotypes such as allergic asthma. Using IgE as a biomarker for asthma provides a target for management and treatment. Biotherapeutics continue to emerge as important advances in asthma treatment, and their effect on IgE and its biomarker role continue to be studied.

Use of biomarkers to identify phenotypes and endotypes of severeasthma

OBJECTIVE

Severe asthma can be classified into phenotypes and endotypes, which may inform clinicians about inflammatory pathways leading to disease and ultimately guide optimal therapeutic strategy. Biomarkers, objectively measurable characteristics of the disease, are of increasing interest to clinicians and researchers as powerful tools to distinguish among the severe asthma phenotypes and endotypes. The objective of this review is to highlight current knowledge of biomarker applications to identify phenotypes and endotypes of severe asthma.

DATA SOURCES

Sources used include observational cohorts, clinical trials, translational studies, comprehensive reviews, and expert/taskforce statements.

STUDY SELECTIONS

Included studies were selected for their relevance to the topic and for strength of data or study design.

RESULTS

In severe asthma, biomarkers can be used for diagnosis of phenotype or endotype, can also be predictive of clinical outcomes or response to therapy, and may be dynamic with time or therapy. Fully determining phenotype or endotype of severe asthma will require interpretation of combinations of commercially available biomarkers.

CONCLUSION

Biomarkers have multiple potential clinical applications in severe asthma. Novel biomarkers may add accuracy to this field.

Increased phosphorylation of eNOS in nasal polyps of chronic rhinosinusitis patients can be diminished by 1,8-cineol

INTRODUCTION

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a significant health problem, but the pathogenesis remains unclear to date. Nitric oxide (NO) has known airway modulating functions. Therefore, we investigated nitric oxide production to determine the role of eNOS in nasal polyps, with additional analysis of the effect of the monoterpene oxide 1,8-cineol on the possible regulation of eNOS signaling and thus NO production.

METHODS

We determined eNOS expression, as well as regulatory and effector proteins like NOSTRIN and CASP8, using whole genome microarray, immunohistochemistry and western blot. To evaluate the influence of 1,8-cineol on eNOS signaling, we examined tissue samples of nasal polyps of patients with CRSwNP incubated with 100 μM 1,8-cineol using quantitative real-time PCR, western blot and phosphorylation arrays.

RESULTS

Microarray analysis revealed an increased gene expression of eNOS (1.40-fold) as well as a decreased gene expression of NOSTRIN (0.53-fold) and CASP8 (0.44-fold) in nasal polyps. At the protein level, we detected 2.3-fold higher protein expression of eNOS and significant higher phosphorylation levels of eNOS in nasal polyps (19.7-fold, p ≤ 0.001) compared to inferior turbinates. Additionally, 1,8-cineol did not influence NOSTRIN and CASP8, but decreased the eNOS phosphorylation significantly (p ≤ 0.05).

DISCUSSION

Our study demonstrated for the first time that nasal polyps exhibit an increased phosphorylation of eNOS, which could be important for vascular permeability and the associated edema and elevated inflammation. Additionally, we detected that 1,8-cineol affects the eNOS phosphorylation significantly and thus its activation. This could be important to handle the elevated inflammation and edema formation by regulating the vascular permeability.