Low levels of endogenous anabolic androgenic steroids in females with severe asthma taking corticosteroids.

Rationale: Patients with severe asthma are dependent upon treatment with high doses of inhaled corticosteroids (ICS) and often also oral corticosteroids (OCS). The extent of endogenous androgenic anabolic steroid (EAAS) suppression in asthma has not previously been described in detail. The objective of the present study was to measure urinary concentrations of EAAS in relation to exogenous corticosteroid exposure. Methods: Urine collected at baseline in the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease outcomes) study of severe adult asthmatics (SA, n=408) was analysed by quantitative mass spectrometry. Data were compared to that of mild-to-moderate asthmatics (MMA, n=70) and healthy subjects (HC, n=98) from the same study. Measurements and main results: The concentrations of urinary endogenous steroid metabolites were substantially lower in SA than in MMA or HC. These differences were more pronounced in SA patients with detectable urinary OCS metabolites. Their dehydroepiandrosterone sulfate (DHEA-S) concentrations were <5% of those in HC, and cortisol concentrations were below the detection limit in 75% of females and 82% of males. The concentrations of EAAS in OCS-positive patients, as well as patients on high-dose ICS only, were more suppressed in females than males (p<0.05). Low levels of DHEA were associated with features of more severe disease and were more prevalent in females (p<0.05). The association between low EAAS and corticosteroid treatment was replicated in 289 of the SA patients at follow-up after 12-18 months. Conclusion: The pronounced suppression of endogenous anabolic androgens in females might contribute to sex differences regarding the prevalence of severe asthma.

Severe asthma trajectories in adults: findings from the NORDSTAR cohort.

BACKGROUND: There is limited evidence on the pathways leading to severe asthma and we are presently unable to effectively predict the progression of the disease. We aimed to describe the longitudinal trajectories leading to severe asthma and to describe clinical events preceding disease progression in a nationwide population of patients with severe asthma. METHODS: We conducted an observational study based on Swedish data from the NORdic Dataset for aSThmA Research (NORDSTAR) research collaboration platform. We identified adult patients with severe asthma in 2018 according to the European Respiratory Society/American Thoracic Society definition and used latent class analysis to identify trajectories of asthma severity over a 10-year retrospective period from 2018. RESULTS: Among 169 128 asthma patients, we identified 4543 severe asthma patients. We identified four trajectories of severe asthma that were labelled as: trajectory 1 "consistently severe asthma" (n=389 (8.6%)), trajectory 2 "gradual onset severe asthma" (n=942 (20.7%)), trajectory 3 "intermittent severe asthma" (n=1685 (37.1%)) and trajectory 4 "sudden onset severe asthma" (n=1527 (33.6%)). "Consistently severe asthma" had a higher daily inhaled corticosteroid dose and more prevalent osteoporosis compared with the other trajectories. Patients with "gradual onset severe asthma" and "sudden onset severe asthma" developed type 2-related comorbidities concomitantly with development of severe asthma. In the latter group, this primarily occurred within 1-3 years preceding onset of severe asthma. CONCLUSIONS: Four distinct trajectories of severe asthma were identified illustrating different patterns of progression of asthma severity. This may eventually enable the development of better preventive management strategies in severe asthma.

The role of inflammation in anxiety and depression in the European U-BIOPRED asthma cohorts.

BACKGROUND: Growing evidence indicates high comorbid anxiety and depression in patients with asthma. However, the mechanisms underlying this comorbid condition remain unclear. The aim of this study was to investigate the role of inflammation in comorbid anxiety and depression in three asthma patient cohorts of the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) project. METHODS: U-BIOPRED was conducted by a European Union consortium of 16 academic institutions in 11 European countries. A subset dataset from subjects with valid anxiety and depression measures and a large blood biomarker dataset were analysed, including 198 non-smoking patients with severe asthma (SAn), 65 smoking patients with severe asthma (SAs), 61 non-smoking patients with mild-to-moderate asthma (MMA), and 20 healthy non-smokers (HC). The Hospital Anxiety and Depression Scale was used to measure anxiety and depression and a series of inflammatory markers were analysed by the SomaScan v3 platform (SomaLogic, Boulder, Colo). ANOVA and the Kruskal-Wallis test were used for multiple-group comparisons as appropriate. RESULTS: There were significant group effects on anxiety and depression among the four cohort groups (p < 0.05). Anxiety and depression of SAn and SAs groups were significantly higher than that of MMA and HC groups (p < 0.05. There were significant differences in serum IL6, MCP1, CCL18, CCL17, IL8, and Eotaxin among the four groups (p < 0.05). Depression was significantly associated with IL6, MCP1, CCL18 level, and CCL17; whereas anxiety was associated with CCL17 only (p < 0.05). CONCLUSIONS: The current study suggests that severe asthma patients are associated with higher levels of anxiety and depression, and inflammatory responses may underlie this comorbid condition.

Characteristics of severe asthma patients on biologics: a real-life European registry study.

Background: The use of anti-interleukin-5 (IL5) for severe asthma is based on criteria from randomised controlled trials (RCTs), but in real-life patients might not fulfil the eligibility criteria but may benefit from biologics. We aimed to characterise patients starting anti-IL5(R) in Europe and evaluate the discrepancies between initiation of anti-IL5(R) in real life and in RCTs. Materials and methods: We performed a cross-sectional analysis with data from the severe asthma patients at the start of anti-IL5(R) in the Severe Heterogeneous Asthma Research collaboration Patient-centred (SHARP Central) registry. We compared the baseline characteristics of the patients starting anti-IL5(R) from 11 European countries within SHARP with the baseline characteristics of the severe asthma patients from 10 RCTs (four for mepolizumab, three for benralizumab and three for reslizumab). Patients were evaluated following eligibility criteria from the RCTs of anti-IL5 therapies. Results: Patients starting anti-IL5(R) in Europe (n=1231) differed in terms of smoking history, clinical characteristics and medication use. The characteristics of severe asthma patients in the SHARP registry differed from the characteristics of patients in RCTs. Only 327 (26.56%) patients fulfilled eligibility criteria of all the RCTs; 24 patients were eligible for mepolizumab, 100 for benralizumab and 52 reslizumab. The main characteristics of ineligibility were: ≥10 pack-years, respiratory diseases other than asthma, Asthma Control Questionnaire score ≤1.5 and low-dose inhaled corticosteroids. Conclusion: A large proportion of patients in the SHARP registry would not have been eligible for anti-IL5(R) treatment in RCTs, demonstrating the importance of real-life cohorts in describing the efficacy of biologics in a broader population of patients with severe asthma.

Evaluation of real-world mepolizumab use in severe asthma across Europe: the SHARP experience with privacy-preserving federated analysis.

Background: An objective of the Severe Heterogeneous Asthma Registry, Patient-centered (SHARP) is to produce real-world evidence on a pan-European scale by linking nonstandardised, patient-level registry data. Mepolizumab has shown clinical efficacy in randomised controlled trials and prospective real-world studies and could therefore serve as a proof of principle for this novel approach. The aim of the present study was to harmonise data from 10 national severe asthma registries and characterise patients receiving mepolizumab, assess its effectiveness on annual exacerbations and maintenance oral glucocorticoid (OCS) use, and evaluate treatment patterns. Methods: In this observational cohort study, registry data (5871 patients) were extracted for harmonisation. Where harmonisation was possible, patients who initiated mepolizumab between 1 January 2016 and 31 December 2021 were examined. Changes of a 12-month (range 11-18 months) period in frequent (two or more) exacerbations, maintenance OCS use and dose were analysed in a privacy-preserving manner using meta-analysis of generalised estimating equation parameters. Periods before and during the coronavirus disease 2019 pandemic were analysed separately. Results: In 912 patients who fulfilled selection criteria, mepolizumab significantly reduced frequent exacerbations (OR 0.18, 95% CI 0.13-0.25), maintenance OCS use (OR 0.75, 95% CI 0.61-0.92) and dose (mean -3.93 mg·day-1, 95% CI -5.24-2.62 mg·day-1) in the pre-pandemic group, with similar trends in the pandemic group. Marked heterogeneity was observed between registries in patient characteristics and mepolizumab treatment patterns. Conclusions: By harmonising patient-level registry data and applying federated analysis, SHARP demonstrated the real-world effectiveness of mepolizumab on asthma exacerbations and maintenance OCS use in severe asthma patients across Europe, consistent with previous evidence. This paves the way for future pan-European real-world severe asthma studies using patient-level data in a privacy-proof manner.

Development of Core Outcome Measures sets for paediatric and adult Severe Asthma (COMSA).

BACKGROUND: Effectiveness studies with biological therapies for asthma lack standardised outcome measures. The COMSA (Core Outcome Measures sets for paediatric and adult Severe Asthma) Working Group sought to develop Core Outcome Measures (COM) sets to facilitate better synthesis of data and appraisal of biologics in paediatric and adult asthma clinical studies. METHODS: COMSA utilised a multi-stakeholder consensus process among patients with severe asthma, adult and paediatric clinicians, pharmaceutical representatives, and health regulators from across Europe. Evidence included a systematic review of development, validity and reliability of selected outcome measures plus a narrative review and a pan-European survey to better understand patients' and carers' views about outcome measures. It was discussed using a modified GRADE (Grading of Recommendations Assessment, Development and Evaluation) Evidence to Decision framework. Anonymous voting was conducted using predefined consensus criteria. RESULTS: Both adult and paediatric COM sets include forced expiratory volume in 1 s (FEV1) as z-scores, annual frequency of severe exacerbations and maintenance oral corticosteroid use. Additionally, the paediatric COM set includes the Paediatric Asthma Quality of Life Questionnaire and Asthma Control Test or Childhood Asthma Control Test, while the adult COM set includes the Severe Asthma Questionnaire and Asthma Control Questionnaire-6 (symptoms and rescue medication use reported separately). CONCLUSIONS: This patient-centred collaboration has produced two COM sets for paediatric and adult severe asthma. It is expected that they will inform the methodology of future clinical trials, enhance comparability of efficacy and effectiveness of biological therapies, and help assess their socioeconomic value. COMSA will inform definitions of non-response and response to biological therapy for severe asthma.

Heterogeneity in the use of biologics for severe asthma in Europe: a SHARP ERS study.

Introduction: Treatment with biologics for severe asthma is informed by international and national guidelines and defined by national regulating bodies, but how these drugs are used in real-life is unknown. Materials and methods: The European Respiratory Society (ERS) SHARP Clinical Research Collaboration conducted a three-step survey collecting information on asthma biologics use in Europe. Five geographically distant countries defined the survey questions, focusing on seven end-points: biologics availability and financial issues, prescription and administration modalities, inclusion criteria, continuation criteria, switching biologics, combining biologics and evaluation of corticosteroid toxicity. The survey was then sent to SHARP National Leads of 28 European countries. Finally, selected questions were submitted to a broad group of 263 asthma experts identified by national societies. Results: Availability of biologics varied between countries, with 17 out of 28 countries having all five existing biologics. Authorised prescribers (pulmonologists and other specialists) also differed. In-hospital administration was the preferred deliverance modality. While exacerbation rate was used as an inclusion criterion in all countries, forced expiratory volume in 1 s was used in 46%. Blood eosinophils were an inclusion criterion in all countries for interleukin-5 (IL-5)-targeted and IL-4/IL-13-targeted biologics, with varying thresholds. There were no formally established criteria for continuing biologics. Reduction in exacerbations represented the most important benchmark, followed by improvement in asthma control and quality of life. Only 73% (191 out of 263) of surveyed clinicians assessed their patients for corticosteroid-induced toxicity. Conclusion: Our study reveals important heterogeneity in the use of asthma biologics across Europe. To what extent this impacts on clinical outcomes relevant to patients and healthcare services needs further investigation.

The effect of the COVID-19 pandemic on severe asthma care in Europe: will care change for good?

Background: The coronavirus disease 2019 (COVID-19) pandemic has put pressure on healthcare services, forcing the reorganisation of traditional care pathways. We investigated how physicians taking care of severe asthma patients in Europe reorganised care, and how these changes affected patient satisfaction, asthma control and future care. Methods: In this European-wide cross-sectional study, patient surveys were sent to patients with a physician-diagnosis of severe asthma, and physician surveys to severe asthma specialists between November 2020 and May 2021. Results: 1101 patients and 268 physicians from 16 European countries contributed to the study. Common physician-reported changes in severe asthma care included use of video/phone consultations (46%), reduced availability of physicians (43%) and change to home-administered biologics (38%). Change to phone/video consultations was reported in 45% of patients, of whom 79% were satisfied or very satisfied with this change. Of 709 patients on biologics, 24% experienced changes in biologic care, of whom 92% were changed to home-administered biologics and of these 62% were satisfied or very satisfied with this change. Only 2% reported worsening asthma symptoms associated with changes in biologic care. Many physicians expect continued implementation of video/phone consultations (41%) and home administration of biologics (52%). Conclusions: Change to video/phone consultations and home administration of biologics was common in severe asthma care during the COVID-19 pandemic and was associated with high satisfaction levels in most but not all cases. Many physicians expect these changes to continue in future severe asthma care, though satisfaction levels may change after the pandemic.

Clinical and transcriptomic features of persistent exacerbation-prone severe asthma in U-BIOPRED cohort.

BACKGROUND: Exacerbation-prone asthma is a feature of severe disease. However, the basis for its persistency remains unclear. OBJECTIVES: To determine the clinical and transcriptomic features of frequent exacerbators (FEs) and persistent FEs (PFEs) in the U-BIOPRED cohort. METHODS: We compared features of FE (≥2 exacerbations in past year) to infrequent exacerbators (IE, <2 exacerbations) and of PFE with repeat ≥2 exacerbations during the following year to persistent IE (PIE). Transcriptomic data in blood, bronchial and nasal epithelial brushings, bronchial biopsies and sputum cells were analysed by gene set variation analysis for 103 gene signatures. RESULTS: Of 317 patients, 62.4% had FE, of whom 63.6% had PFE, while 37.6% had IE, of whom 61.3% had PIE. Using multivariate analysis, FE was associated with short-acting beta-agonist use, sinusitis and daily oral corticosteroid use, while PFE was associated with eczema, short-acting beta-agonist use and asthma control index. CEA cell adhesion molecule 5 (CEACAM5) was the only differentially expressed transcript in bronchial biopsies between PE and IE. There were no differentially expressed genes in the other four compartments. There were higher expression scores for type 2, T-helper type-17 and type 1 pathway signatures together with those associated with viral infections in bronchial biopsies from FE compared to IE, while there were higher expression scores of type 2, type 1 and steroid insensitivity pathway signatures in bronchial biopsies of PFE compared to PIE. CONCLUSION: The FE group and its PFE subgroup are associated with poor asthma control while expressing higher type 1 and type 2 activation pathways compared to IE and PIE, respectively.

Allergen provocation tests in respiratory research: building on 50†years of experience.

The allergen provocation test is an established model of allergic airway diseases, including asthma and allergic rhinitis, allowing the study of allergen-induced changes in respiratory physiology and inflammatory mechanisms in sensitised individuals as well as their associations. In the upper airways, allergen challenge is focused on the clinical and pathophysiological sequelae of the early allergic response, and is applied both as a diagnostic tool and in research settings. In contrast, bronchial allergen challenge has almost exclusively served as a research tool in specialised research settings with a focus on the late asthmatic response and the underlying type 2 inflammation. The allergen-induced late asthmatic response is also characterised by prolonged airway narrowing, increased nonspecific airway hyperresponsiveness and features of airway remodelling including the small airways, and hence allows the study of several key mechanisms and features of asthma. In line with these characteristics, allergen challenge has served as a valued tool to study the cross-talk of the upper and lower airways and in proof-of-mechanism studies of drug development. In recent years, several new insights into respiratory phenotypes and endotypes including the involvement of the upper and small airways, innovative biomarker sampling methods and detection techniques, refined lung function testing as well as targeted treatment options further shaped the applicability of the allergen provocation test in precision medicine. These topics, along with descriptions of subject populations and safety, in line with the updated Global Initiative for Asthma 2021 document, will be addressed in this review.

Plasma proteins elevated in severe asthma despite oral steroid use and unrelated to Type-2 inflammation.

RATIONALE: Asthma phenotyping requires novel biomarker discovery. OBJECTIVES: To identify plasma biomarkers associated with asthma phenotypes by application of a new proteomic panel to samples from two well-characterised cohorts of severe (SA) and mild-to-moderate (MMA) asthmatics, COPD subjects and healthy controls (HCs). METHODS: An antibody-based array targeting 177 proteins predominantly involved in pathways relevant to inflammation, lipid metabolism, signal transduction and extracellular matrix was applied to plasma from 525 asthmatics and HCs in the U-BIOPRED cohort, and 142 subjects with asthma and COPD from the validation cohort BIOAIR. Effects of oral corticosteroids (OCS) were determined by a 2-week, placebo-controlled OCS trial in BIOAIR, and confirmed by relation to objective OCS measures in U-BIOPRED. RESULTS: In U-BIOPRED, 110 proteins were significantly different, mostly elevated, in SA compared to MMA and HCs. 10 proteins were elevated in SA versus MMA in both U-BIOPRED and BIOAIR (alpha-1-antichymotrypsin, apolipoprotein-E, complement component 9, complement factor I, macrophage inflammatory protein-3, interleukin-6, sphingomyelin phosphodiesterase 3, TNF receptor superfamily member 11a, transforming growth factor-ß and glutathione S-transferase). OCS treatment decreased most proteins, yet differences between SA and MMA remained following correction for OCS use. Consensus clustering of U-BIOPRED protein data yielded six clusters associated with asthma control, quality of life, blood neutrophils, high-sensitivity C-reactive protein and body mass index, but not Type-2 inflammatory biomarkers. The mast cell specific enzyme carboxypeptidase A3 was one major contributor to cluster differentiation. CONCLUSIONS: The plasma proteomic panel revealed previously unexplored yet potentially useful Type-2-independent biomarkers and validated several proteins with established involvement in the pathophysiology of SA.

Urinary metabotype of severe asthma evidences decreased carnitine metabolism independent of oral corticosteroid treatment in the U-BIOPRED study.

INTRODUCTION: Asthma is a heterogeneous disease with poorly defined phenotypes. Patients with severe asthma often receive multiple treatments including oral corticosteroids (OCS). Treatment may modify the observed metabotype, rendering it challenging to investigate underlying disease mechanisms. Here, we aimed to identify dysregulated metabolic processes in relation to asthma severity and medication. METHODS: Baseline urine was collected prospectively from healthy participants (n=100), patients with mild-to-moderate asthma (n=87) and patients with severe asthma (n=418) in the cross-sectional U-BIOPRED cohort; 12-18-month longitudinal samples were collected from patients with severe asthma (n=305). Metabolomics data were acquired using high-resolution mass spectrometry and analysed using univariate and multivariate methods. RESULTS: A total of 90 metabolites were identified, with 40 significantly altered (p<0.05, false discovery rate <0.05) in severe asthma and 23 by OCS use. Multivariate modelling showed that observed metabotypes in healthy participants and patients with mild-to-moderate asthma differed significantly from those in patients with severe asthma (p=2.6×10-20), OCS-treated asthmatic patients differed significantly from non-treated patients (p=9.5×10-4), and longitudinal metabotypes demonstrated temporal stability. Carnitine levels evidenced the strongest OCS-independent decrease in severe asthma. Reduced carnitine levels were associated with mitochondrial dysfunction via decreases in pathway enrichment scores of fatty acid metabolism and reduced expression of the carnitine transporter SLC22A5 in sputum and bronchial brushings. CONCLUSIONS: This is the first large-scale study to delineate disease- and OCS-associated metabolic differences in asthma. The widespread associations with different therapies upon the observed metabotypes demonstrate the need to evaluate potential modulating effects on a treatment- and metabolite-specific basis. Altered carnitine metabolism is a potentially actionable therapeutic target that is independent of OCS treatment, highlighting the role of mitochondrial dysfunction in severe asthma.

Distinct plasma biomarkers confirm the diagnosis of mastocytosis and identify increased risk of anaphylaxis.

BACKGROUND: Mastocytosis encompasses a heterogeneous group of disorders characterized by accumulation of clonal mast cells (MCs) in the skin and/or internal organs. Patients typically present with a broad variety of recurrent mediator-related clinical symptoms, including severe anaphylaxis. However, not all patients with mastocytosis experience anaphylactic reactions. OBJECTIVE: We sought to identify disease-specific biomarkers in plasma that could be used to predict patients with mastocytosis with increased risk of anaphylaxis. METHODS: Nineteen patients (≥18 years) and 2 control groups (11 subjects with allergic asthma and 13 healthy volunteers without history of atopy) were recruited. In total, 248 plasma proteins were analyzed by Proximity Extension Assay using Olink Proseek Multiplex panels. RESULTS: We identified 4 novel proteins, in addition to tryptase, E-selectin, adrenomedullin, T-cell immunoglobulin, and mucin domain 1, and CUB domain-containing protein 1/CD138 to be significantly increased in patients with mastocytosis compared with both patients with asthma and healthy controls. Furthermore, we investigated whether we could discriminate between patients with mastocytosis with or without anaphylaxis. In addition to tryptase, we identified 3 novel proteins, that is, allergin-1, pregnancy-associated plasma protein-A, and galectin-3, with significantly different levels in patients with mastocytosis with anaphylaxis compared with those without anaphylaxis. CONCLUSIONS: Newly identified proteomic biomarkers may be used to predict patients with mastocytosis with increased risk of anaphylaxis.

Medication Adherence in Patients With Severe Asthma Prescribed Oral Corticosteroids in the U-BIOPRED Cohort.

BACKGROUND: Although estimates of suboptimal adherence to oral corticosteroids in asthma range from 30% to 50%, no ideal method for measurement exists; the impact of poor adherence in severe asthma is likely to be particularly high. RESEARCH QUESTIONS: What is the prevalence of suboptimal adherence detected by self-reporting and direct measures? Is suboptimal adherence associated with disease activity? STUDY DESIGN AND METHODS: Data were included from individuals with severe asthma taking part in the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) study and prescribed daily oral corticosteroids. Participants completed the Medication Adherence Report Scale, a five-item questionnaire used to grade adherence on a scale from 1 to 5, and provided a urine sample for analysis of prednisolone and metabolites by liquid chromatography-mass spectrometry. RESULTS: Data from 166 participants were included in this study: mean (SD) age, 54.2 (± 11.9) years; FEV1, 65.1% (± 20.5%) predicted; female, 58%; 37% completing the Medication Adherence Report Scale reported suboptimal adherence; and 43% with urinary corticosteroid data did not have detectable prednisolone or metabolites in their urine. Good adherence by both methods was detected in 49 of the 142 (35%) of participants in whom both methods were performed; adherence detection did not match between methods in 53%. Self-reported high adherers had better asthma control and quality of life, whereas directly measured high adherers had lower blood eosinophil levels. INTERPRETATION: Low adherence is a common problem in severe asthma, whether measured directly or self-reported. We report poor agreement between the two methods, suggesting some disassociation between self-assessment of medication adherence and regular oral corticosteroid use, which suggests that each approach may provide complementary information in clinical practice.

Lung function fluctuation patterns unveil asthma and COPD phenotypes unrelated to type 2 inflammation.

BACKGROUND: In all chronic airway diseases, the dynamics of airway function are influenced by underlying airway inflammation and bronchial hyperresponsiveness along with limitations in reversibility owing to airway and lung remodeling as well as mucous plugging. The relative contribution of each component translates into specific clinical patterns of symptoms, quality of life, exacerbation risk, and treatment success. OBJECTIVE: We aimed to evaluate whether subgrouping of patients with obstructive airway diseases according to patterns of fluctuation in lung function allows identification of specific phenotypes with distinct clinical characteristics. METHODS: We applied the novel method of fluctuation-based clustering (FBC) to twice-daily FEV1 measurements recorded over a 1-year period in a mixed group of 134 adults with mild-to-moderate asthma, severe asthma, or chronic obstructive pulmonary disease from the European BIOAIR cohort. RESULTS: Independently of clinical diagnosis, FBC divided patients into 4 fluctuation-based clusters with progressively increasing alterations in lung function that corresponded to patterns of increasing clinical severity, risk of exacerbation, and lower quality of life. Clusters of patients with airway disease with significantly elevated levels of biomarkers relating to remodeling (osteonectin) and cellular senescence (plasminogen activator inhibitor-1), accompanied by a loss of airway reversibility, pulmonary hyperinflation, and loss of diffusion capacity, were identified. The 4 clusters generated were stable over time and revealed no differences in levels of markers of type 2 inflammation (blood eosinophils and periostin). CONCLUSION: FBC-based phenotyping provides another level of information that is complementary to clinical diagnosis and unrelated to eosinophilic inflammation, which could identify patients who may benefit from specific treatment strategies or closer monitoring.

Selective inhibition of prostaglandin D2 biosynthesis in human mast cells to overcome need for multiple receptor antagonists: Biochemical consequences.

BACKGROUND: The major mast cell prostanoid PGD2 is targeted for therapy of asthma and other diseases, because the biological actions include bronchoconstriction, vasodilation and regulation of immune cells mediated by three different receptors. It is not known if the alternative to selectively inhibit the biosynthesis of PGD2 affects release of other prostanoids in human mast cells. OBJECTIVES: To determine the biochemical consequences of inhibition of the hematopoietic prostaglandin D synthase (hPGDS) PGD2 in human mast cells. METHODS: Four human mast cell models, LAD2, cord blood derived mast cells (CBMC), peripheral blood derived mast cells (PBMC) and human lung mast cells (HLMC), were activated by anti-IgE or ionophore A23187. Prostanoids were measured by UPLC-MS/MS. RESULTS: All mast cells almost exclusively released PGD2 when activated by anti-IgE or A23187. The biosynthesis was in all four cell types entirely initiated by COX-1. When pharmacologic inhibition of hPGDS abolished formation of PGD2 , PGE2 was detected and release of TXA2 increased. Conversely, when the thromboxane synthase was inhibited, levels of PGD2 increased. Adding exogenous PGH2 confirmed predominant conversion to PGD2 under control conditions, and increased levels of TXB2 and PGE2 when hPGDS was inhibited. However, PGE2 was formed by non-enzymatic degradation. CONCLUSIONS: Inhibition of hPGDS effectively blocks mast cell dependent PGD2 formation. The inhibition was associated with redirected use of the intermediate PGH2 and shunting into biosynthesis of TXA2 . However, the levels of TXA2 did not reach those of PGD2 in naïve cells. It remains to determine if this diversion occurs in vivo and has clinical relevance.

Urinary Leukotriene E4 and Prostaglandin D2 Metabolites Increase in Adult and Childhood Severe Asthma Characterized by Type 2 Inflammation. A Clinical Observational Study.

Rationale: New approaches are needed to guide personalized treatment of asthma.Objectives: To test if urinary eicosanoid metabolites can direct asthma phenotyping.Methods: Urinary metabolites of prostaglandins (PGs), cysteinyl leukotrienes (CysLTs), and isoprostanes were quantified in the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Diseases Outcomes) study including 86 adults with mild-to-moderate asthma (MMA), 411 with severe asthma (SA), and 100 healthy control participants. Validation was performed internally in 302 participants with SA followed up after 12-18 months and externally in 95 adolescents with asthma.Measurement and Main Results: Metabolite concentrations in healthy control participants were unrelated to age, body mass index, and sex, except for the PGE2 pathway. Eicosanoid concentrations were generally greater in participants with MMA relative to healthy control participants, with further elevations in participants with SA. However, PGE2 metabolite concentrations were either the same or lower in male nonsmokers with asthma than in healthy control participants. Metabolite concentrations were unchanged in those with asthma who adhered to oral corticosteroid treatment as documented by urinary prednisolone detection, whereas those with SA treated with omalizumab had lower concentrations of LTE4 and the PGD2 metabolite 2,3-dinor-11ß-PGF2α. High concentrations of LTE4 and PGD2 metabolites were associated with lower lung function and increased amounts of exhaled nitric oxide and eosinophil markers in blood, sputum, and urine in U-BIOPRED participants and in adolescents with asthma. These type 2 (T2) asthma associations were reproduced in the follow-up visit of the U-BIOPRED study and were found to be as sensitive to detect T2 inflammation as the established biomarkers.Conclusions: Monitoring of urinary eicosanoids can identify T2 asthma and introduces a new noninvasive approach for molecular phenotyping of adult and adolescent asthma.Clinical trial registered with www.clinicaltrials.gov (NCT01976767).

Airway Elastin is increased in severe asthma and relates to proximal wall area: histological and computed tomography findings from the U-BIOPRED severe asthma study.

BACKGROUND: Airway remodelling, which may include goblet cell hyperplasia / hypertrophy, changes in epithelial integrity, accumulation of extracellular matrix components, smooth muscle hypertrophy and thickening of the lamina reticularis, is a feature of severe asthma and contributes to the clinical phenotype. OBJECTIVE: Within the U-BIOPRED severe asthma study, we have assessed histological elements of airway remodelling and their relationship to computed tomography (CT) measures of proximal airway dimensions. METHODS: Bronchial biopsies were collected from two severe asthma groups, one non-smoker (SAn, n = 28) and one current/ex-smoker (SAs/ex, n = 13), and a mild-moderate asthma group (MMA, n = 28) classified and treated according to GINA guidelines, plus a healthy control group (HC, n = 33). Movat's pentachrome technique was used to identify mucin, elastin and total collagen in these biopsies. The number of goblet cells (mucin+) was counted as a percentage of the total number of epithelial cells and the percentage mucin epithelial area measured. The percentage area of elastic fibres and total collagen within the submucosa was also measured, and the morphology of the elastic fibres classified. Participants in the asthma groups also had a CT scan to assess large airway morphometry. RESULTS: The submucosal tissue elastin percentage was higher in both severe asthma groups (16.1% SAn, 18.9% SAs/ex) compared with the HC (9.7%) but did not differ between asthma groups. There was a positive relationship between elastin and airway wall area measured by CT (n = 18-20, rho=0.544, p = 0.024), which also related to an increase in elastic fibres with a thickened lamellar morphological appearance. Mucin epithelial area and total collagen were not different between the four groups. Due to small numbers of suitable CT scans, it was not feasible to compare airway morphometry between the asthma groups. CONCLUSION: These findings identify a link between extent of elastin deposition and airway wall thickening in severe asthma.