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Nicole MD van der Burg, Carl Ekelund, Leif H Bjermer, David Aronsson, Jaro Ankerst, Ellen Tufvesson Department of Clinical Sciences Lund, Respiratory Medicine, Allergology and Palliative Medicine, Lund University, Lund, SwedenCorrespondence: Ellen Tufvesson, Department of Clinical Sciences Lund, Respiratory Medicine, Allergology and Palliative Medicine, Lund University, BMC, D12, Lund, 221 84, Sweden, Email Ellen.Tufvesson@med.lu.seBackground: Bronchodilator responsiveness (BDR) in asthma involves both the central and peripheral airways but is primarily relieved with beta-2-agonists and evaluated by spirometry. To date, antimuscarinics can be added as a reliever medication in more severe asthma. We hypothesize that combining both short-acting beta-2 agonist (SABA) and short-acting muscarinic antagonist (SAMA) could also improve the responsiveness in mild-moderate asthma. Therefore, we aimed to compare the direct effects of inhaling SABA alone, SAMA alone or combining both SABA and SAMA on the central and peripheral airways in asthma.Methods: Twenty-three patients with mild-moderate BDR in asthma performed dynamic spirometry and impulse oscillometry before (baseline) and multiple timepoints within an hour after inhalation of SABA (salbutamol), SAMA (ipratropium bromide), or both SABA and SAMA at three different visits.Results: The use of SAMA alone did not show any improvement compared to the use of SABA alone. Inhalation of SABA+SAMA, however, averaged either similar or better BDR than SABA alone in FEV1, MMEF, FVC, R5, R20 and R5-R20. Inhaling SABA+SAMA reached a stable BDR in more patients within 0– 10 minutes and also reached the FEV1 (Δ%)> 12% faster (3.5 minutes) than inhaling SABA alone (5.1 minutes). Inhaling SABA+SAMA was significantly better than SAMA alone in FEV1 (p = 0.015), MMEF (p = 0.0059) and R20 (p = 0.0049). Using these three variables highlighted a subgroup (30%, including more males) of patients that were more responsive to inhaling SABA+SAMA than SABA alone.Conclusion: Overall, combining SAMA with SABA was faster and more consistent at increasing the lung function than SABA alone or SAMA alone, and the additive effect was best captured by incorporating peripheral-related variables. Therefore, SAMA should be considered as an add-on reliever for mild-moderate patients with BDR in asthma.Keywords: BDR, mild-moderate asthma, central airway, peripheral airways, SABA, SAMA

Martin Garcia-Ryde,1 Nicole MD van der Burg,1 Carin E Larsson,1 Anna-Karin Larsson-Callerfelt,2 Gunilla Westergren-Thorsson,2 Leif Bjermer,1 Ellen Tufvesson1 1Department of Clinical Sciences Lund, Respiratory Medicine, Allergology and Palliative Medicine, Lund University, Lund, Sweden; 2Department of Experimental Medical Science, Lung Biology, Lund University, Lund, SwedenCorrespondence: Ellen Tufvesson, Department of Clinical Sciences Lund, Respiratory Medicine, Allergology and Palliative Medicine, Lund University, BMC, D12, 221 84, Lund, Sweden, Email Ellen.Tufvesson@med.lu.seBackground and aim: Cigarette smoking is the most common cause of chronic obstructive pulmonary disease (COPD) but more mechanistic studies are needed. Cigarette smoke extract (CSE) can elicit a strong response in many COPD-related cell types, but no studies have been performed in lung fibroblasts. Therefore, we aimed to investigate the effect of CSE on gene expression in lung fibroblasts from healthy and COPD subjects.Patients and methods: Primary lung fibroblasts, derived from six healthy and six COPD subjects (all current or ex-smokers), were either unstimulated (baseline) or stimulated with 30% CSE for 4 h prior to RNA isolation. The mRNA expression levels were measured using the NanoString nCounter Human Fibrosis V2 panel (760 genes). Pathway enrichment was assessed for unique gene ontology terms of healthy and COPD.Results: At baseline, a difference in the expression of 17 genes was found in healthy and COPD subjects. Differential expression of genes after CSE stimulation resulted in significantly less changes in COPD lung fibroblasts (70 genes) than in healthy (207 genes), with 51 genes changed in both. COPD maintained low NOTCH signaling throughout and upregulated JUN > 80%, indicating an increase in apoptosis. Healthy downregulated the Mitogen-activated protein kinase (MAPK) signaling cascade, including a ≥ 50% reduction in FGF2, CRK, TGFBR1 and MEF2A. Healthy also downregulated KAT6A and genes related to cell proliferation, all together indicating possible cell senescence signaling.Conclusion: Overall, COPD lung fibroblasts responded to CSE stimulation with a very different and deficient expression profile compared to healthy. Highlighting that stimulated healthy cells are not an appropriate substitute for COPD cells which is important when investigating the mechanisms of COPD.Plain Language Summary: We investigated, for the first time, the effect of cigarette smoke extract (CSE) on gene expression in lung fibroblasts from healthy subjects and subjects with COPD. We found that fibroblasts from subjects with COPD respond very differently than from healthy subjects by changing fewer gene expressions after CSE. Pathway enrichment suggested that fibroblasts from subjects with COPD respond to CSE by affecting genes involved in apoptosis pathways, while fibroblasts from healthy subjects respond by affecting genes involved in cell senescence. This study highlights the importance of assessing stimulated COPD cells in mechanistic studies.Keywords: COPD, lung fibroblast, gene expression, cigarette smoke extract, GO term, signaling pathways

Tufvesson E, Radner F, Papapostolou G, et al. Int J Chron Obstruct Pulmon Dis. 2020;15:3003–3012. Page 3004, left column, line 2 from the bottom, the sentence “The study also included a new WMAX test where the participants started biking with a 3-min warm-up at 40% of their predicted WMAX, followed by an instant increase to 70% and then a linear increase in workload to achieve the predicted WMAX within 8 min” should read “The study also included a new WMAX test where the participants started biking with a 3-min warm-up at 40% of their predicted WMAX, followed by a linear increase in workload to achieve the predicted WMAX within 8 min”. Page 3005, left column, line 4 from the bottom, the sentence “The new maximum test included an initial phase of pedalling for 3 min at 40% (Study A) or 30% (Study B) of the predicted WMAX, followed by an instant increase to 75% (Study A) or 70% (Study B), followed by a stepwise (Study A) or linear (Study B) increase in workload until exhaustion” should read “The new maximum test included an initial phase of pedalling for 3 min at 40% (Study A) or 30% (Study B) of the predicted WMAX, followed by a linear increase in workload to achieve the predicted WMAX within 8 min”. The authors apologize for these errors. Read the original article

Over the past years, eosinophils have become a focus of scientific interest, especially in the context of their recently uncovered functions (e.g. antiviral, anti-inflammatory, regulatory). These versatile cells display both beneficial and detrimental activities under various physiological and pathological conditions. Eosinophils are involved in the pathogenesis of many diseases which can be classified into primary (clonal) and secondary (reactive) disorders and idiopathic (hyper)eosinophilic syndromes. Depending on the biological specimen, the eosinophil count in different body compartments may serve as a biomarker reflecting the underlying pathophysiology and/or activity of distinct diseases and as a therapy-driving (predictive) and monitoring tool. Personalized selection of an appropriate therapeutic strategy directly or indirectly targeting the increased number and/or activity of eosinophils should be based on the understanding of eosinophil homeostasis including their interactions with other immune and non-immune cells within different body compartments. Hence, restoring as well as maintaining homeostasis within an individual's eosinophil pool is a goal of both specific and non-specific eosinophil-targeting therapies. Despite the overall favourable safety profile of the currently available anti-eosinophil biologics, the effect of eosinophil depletion should be monitored from the perspective of possible unwanted consequences., (© 2023 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Introduction: Very preterm birth is associated with lung function impairment later in life, but several aspects have not been studied. We aimed to comprehensively assess lung function at school age in very preterm infants and term controls, with special emphasis on bronchopulmonary dysplasia (BPD), sex, and bronchodilator response., Methods: At 12 years of age, 136 children born very preterm (85 with and 51 without BPD) and 56 children born at term performed spirometry, body plethysmography, impulse oscillometry, measurement of diffusion capacity, and multiple breath washout, before and after bronchodilator inhalation., Results: Airway symptoms and a diagnosis of asthma were more common in children born very preterm. These children had more airflow limitation, seen as lower forced expiratory volume in 1 s (FEV 1 ) (p < .001), FEV 1 /forced vital capacity (FVC) (p = .011), and mean forced expiratory flow between 25% and 75% of FVC (p < .001), and a higher total and peripheral airway resistance compared with term-born controls. There was no difference in total lung capacity but air trapping and lung clearance index were higher in children born very preterm. Diffusion capacity was lower in children born very preterm, especially in those with a diagnosis of BPD. In most other tests, the differences between preterm-born children with or without BPD were smaller than between children born preterm versus at term. Boys born preterm had more lung function deficits than preterm-born girls. In children born very preterm, airway obstruction was to a large extent reversible., Conclusion: At 12 years of age, children born very preterm had lower lung function than children born at term in most aspects and there was only little difference between children with or without BPD. Airway obstruction improved markedly after bronchodilator inhalation., (© 2023 The Authors. Pediatric Pulmonology published by Wiley Periodicals LLC.)

Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Introduction: Chronic lung disorders involve pathological alterations in the lung tissue with hypoxia as a consequence. Hypoxia may influence the release of inflammatory mediators and growth factors including vascular endothelial growth factor (VEGF) and prostaglandin (PG)E 2 . The aim of this work was to investigate how hypoxia affects human lung epithelial cells in combination with profibrotic stimuli and its correlation to pathogenesis. Methods: Human bronchial (BEAS-2B) and alveolar (hAELVi) epithelial cells were exposed to either hypoxia (1% O 2 ) or normoxia (21% O 2 ) during 24 h, with or without transforming growth factor (TGF)-β1. mRNA expression of genes and proteins related to disease pathology were analysed with qPCR, ELISA or immunocytochemistry. Alterations in cell viability and metabolic activity were determined. Results: In BEAS-2B and hAELVi, hypoxia significantly dowregulated genes related to fibrosis, mitochondrial stress, oxidative stress, apoptosis and inflammation whereas VEGF receptor 2 increased. Hypoxia increased the expression of Tenascin-C, whereas both hypoxia and TGF-β1 stimuli increased the release of VEGF, IL-6, IL-8 and MCP-1 in BEAS-2B. In hAELVi, hypoxia reduced the release of fibroblast growth factor, epidermal growth factor, PGE 2 , IL-6 and IL-8, whereas TGF-β1 stimulus significantly increased the release of PGE 2 and IL-6. TGF-β1 stimulated BEAS-2B cells showed a decreased release of VEGF-A and IL-8, while TGF-β1 stimulated hAELVi cells showed a decreased release of PGE 2 and IL-8 during hypoxia compared to normoxia. Metabolic activity was significantly increased by hypoxia in both epithelial cell types. Discussion: In conclusion, our data indicate that bronchial and alveolar epithelial cells respond differently to hypoxia and profibrotic stimuli. The bronchial epithelium appears more responsive to changes in oxygen levels and remodelling processes compared to the alveoli, suggesting that hypoxia may be a driver of pathogenesis in chronic lung disorders., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Berggren-Nylund, Ryde, Löfdahl, Ibáñez-Fonseca, Kåredal, Westergren-Thorsson, Tufvesson and Larsson-Callerfelt.)

Introduction: Allergic asthmatics with both an early (EAR) and a late allergic reaction (LAR) following allergen exposure are termed 'dual responders' (DR), while 'single responders' (SR) only have an EAR. Mechanisms that differentiate DR from SR are largely unknown, particularly regarding the role and phenotypes of neutrophils. Therefore, we aimed to study neutrophils in DR and SR asthmatics., Methods: Thirty-four allergic asthmatics underwent an inhaled allergen challenge, samples were collected before and up to 24 h post-challenge. Cell differentials were counted from bronchial lavage, alveolar lavage and blood; and tissue neutrophils were quantified in immune-stained bronchial biopsies. Lavage neutrophil nuclei lobe segmentation was used to classify active (1-4 lobes) from suppressive neutrophils (≥5 lobes). Levels of transmigration markers: soluble (s)CD62L and interleukin-1Ra, and activity markers: neutrophil elastase (NE), DNA-histone complex and dsDNA were measured in lavage fluid and plasma., Results: Compared with SR at baseline, DR had more neutrophils in their bronchial airways at baseline, both in the lavage (p = .0031) and biopsies (p = .026) and elevated bronchial neutrophils correlated with less antitransmigratory IL-1Ra levels (r = -0.64). DR airways had less suppressive neutrophils and more 3-lobed (active) neutrophils (p = .029) that correlated with more bronchial lavage histone (p = .020) and more plasma NE (p = .0016). Post-challenge, DR released neutrophil extracellular trap factors in the blood earlier and had less pro-transmigratory sCD62L during the late phase (p = .0076) than in SR., Conclusion: DR have a more active airway neutrophil phenotype at baseline and a distinct neutrophil response to allergen challenge that may contribute to the development of an LAR. Therefore, neutrophil activity should be considered during targeted diagnosis and bio-therapeutic development for DR., (© 2022 The Authors. Clinical & Experimental Allergy published by John Wiley & Sons Ltd.)

Objective: The aim of this study was to investigate if desquamated oral epithelial cells (DOECs) express the epidermal growth factor (EGF) and if these cells thereby may contribute to salivary EGF contents., Background: DOECs have recently been shown to harbor the antimicrobial peptide LL-37, proposing that they may also store other biologically important salivary peptides/proteins. The EGF peptide is a growth factor which plays a critical role to maintain epithelial integrity and promote epithelial healing. The EGF is produced by salivary glands, but it is not known whether DOECs contain the EGF and thereby contribute to salivary EGF levels., Materials and Methods: DOECs were isolated from unstimulated whole saliva collected from four healthy volunteers. EGF protein expression was determined in cell lysates by dot blot and ELISA. Cellular distribution of cytokeratin, the proliferation marker Ki67, and EGF immunoreactivity were assessed by immunocytochemistry. EGF gene expression was investigated by qPCR. Expression of EGF transcript and protein in DOECs was compared to that in the human cultured keratinocyte cell line (HaCaT) cells., Results: EGF protein expression was detected in DOEC cell lysates by both dot blot and ELISA. Strong cytoplasmic EGF immunoreactivity was observed in DOECs, although some cells showed only a weak immunoreactive signal for EGF. Moreover, DOECs, besides containing EGF protein, also expressed transcript for EGF. Interestingly, ELISA analysis revealed that EGF protein contents were higher in DOECs than in HaCaT cells. ELISA analysis also disclosed that EGF concentration was about 10 times higher in whole saliva compared to DOECs. EGF transcript expression was about 50% lower in HaCaT cells stimulated with high (10%) compared to low (0.1%) concentration of fetal bovine serum, representing growth-stimulated and growth-restricted conditions, respectively, implying that growth-stimulus exerts negative feedback on EGF gene activity in HaCaT cells., Conclusion: Here, we show for the first time that DOECs express the EGF, arguing that these cells contribute to salivary EGF contents and hence may play a role in gingival epithelial repair and wound healing., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Alexandra Aidoukovitch et al.)

Purpose: Exposure to cold air may harm the airways. It is unclear to what extent heavy exercise adds to the cold-induced effects on peripheral airways, airway epithelium, and systemic immunity among healthy individuals. We investigated acute effects of heavy exercise in sub-zero temperatures on the healthy airways., Methods: Twenty-nine healthy individuals underwent whole body exposures to cold air in an environmental chamber at - 15 °C for 50 min on two occasions; a 35-min exercise protocol consisting of a 5-min warm-up followed by 2 × 15 min of running at 85% of VO 2 max vs. 50 min at rest. Lung function was measured by impulse oscillometry (IOS) and spirometry before and immediately after exposures. CC16 in plasma and urine, and cytokines in plasma were measured before and 60 min after exposures. Symptoms were surveyed pre-, during and post-trials., Results: FEV 1 decreased after rest (- 0.10 ± 0.03 L, p < 0.001) and after exercise (- 0.06 ± 0.02 L, p = 0.012), with no difference between trials. Exercise in - 15 °C induced greater increases in lung reactance (X5; p = 0.023), plasma CC16 (p < 0.001) as well as plasma IL-8 (p < 0.001), compared to rest. Exercise induced more intense symptoms from the lower airways, whereas rest gave rise to more general symptoms., Conclusion: Heavy exercise during cold air exposure at - 15 °C induced signs of an airway constriction to a similar extent as rest in the same environment. However, biochemical signs of airway epithelial stress, cytokine responses, and symptoms from the lower airways were more pronounced after the exercise trial., (© 2022. The Author(s).)

Tissue damage, epithelial alterations, and intraepithelial presence of mast cells (MCs) are characteristics of asthma pathogenesis. Increased alveolar infiltration of MC populations has also been identified as a feature of asthma and other chronic respiratory diseases. The asthma associated receptor, urokinase plasminogen activator receptor (uPAR), has been shown to regulate bronchial epithelial repair responses. However, the impact of MC tryptase and chymase on functional properties and expression of uPAR in alveolar epithelial cells have not been fully investigated. Alveolar epithelial cell migration and wound healing were investigated using holographic live cell imaging of A549 cells in a wound scratch model post stimulation with tryptase or chymase. The expression of uPAR was investigated on the protein and gene level from cellular supernatants and in bronchoalveolar lavage fluid fractions from allergic asthmatics. We found that tryptase improved wound healing capacity, cellular migration and membrane bound uPAR expression. Chymase reduced gap closure capacity, cellular migration and membrane bound uPAR expression but increased soluble uPAR release. Our data suggest a dual regulatory response from the MC proteases in events related to uPAR expression and wound healing which could be important features in asthmatic disease.

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., Competing Interests: G.M. Gauvreau declares grants from AstraZeneca, Biohaven, Novartis and Genentech; consulting fees from AstraZeneca, Biohaven, Novartis, Sterna Biologicals and Certior Consulting; and payment or honoraria from AstraZeneca, Genzyme and Genentech, all in the 36 months prior to manuscript submission. B.E. Davis declares no competing interests. G. Scadding declares support from ALK-Abelló (provision of active and placebo medication for the GRASS clinical trial referenced in the article) and the Immune Tolerance Network (NIAID, NIH, USA; sponsor of the GRASS clinical trial) related to the present manuscript; as well as payment for lectures from ALK-Abelló in 2020 and 2021; and support from GlaxoSmithKline for attendance at the 2021 European Academy of Allergy and Clinical Immunology meeting. L-P. Boulet declares research grants for participation in multicentre studies or research projects proposed by the investigator from Amgen, AstraZeneca, GlaxoSmithKline, Merck, Novartis and Sanofi-Regeneron; royalties from UptoDate and Taylor & Francis; lecture fees from AstraZeneca, Covis, GlaxoSmithKline, Novartis, Merck and Sanofi, all in the 36 months prior to manuscript submission; and the following unpaid contributions: Chair of the Global Initiative for Asthma (GINA) Board of Directors; President of the Global Asthma Organisation (Interasma); Member of the Canadian Thoracic Society Respiratory Guidelines Committee; and Laval University Chair on Knowledge Transfer, Prevention and Education in Respiratory and Cardiovascular Health. L. Bjermer declares no competing interests. A. Chaker declares grants or contracts, via Technical University Munich, from EIT Health (European Institute of Technology), BMBF (German Federal Ministry of Education and Research), AstraZeneca, Sanofi-Genzyme, Roche, GlaxoSmithKline and ALK-Abelló; payments or honoraria, via Technical University Munich, from ALK-Abelló, Allergopharma, AstraZeneca, GlaxoSmithKline, Immunotek, Novartis, Regeneron, Sanofi-Genzyme, Leti, Zeller and Bencard; travel reimbursement to attend European Academy of Allergy and Clinical Immunology meetings (2018 and 2021 from the European Academy of Allergy and Clinical Immunology; 2019 from ALK-Abelló); patents, via Technical University Munich, relating to allergen-specific immunotherapy and treatment of SARS-CoV-2 infection; participation, via Technical University Munich, on a data safety monitoring board or advisory board for ALK-Abelló, Allergopharma, AstraZeneca, GlaxoSmithKline, Immunotek, Novartis, Regeneron and Sanofi-Genzyme; and the following unpaid roles: Past Chair of the Allergy, Clinical Immunology and Environmental Medicine Section of the German ENT Society; board member at large of the German Allergy Society (DGAKI); scientific advisor/board member to the German Society for Applied Allergy (AeDA); board member of the Allergen Immuntherapy Interest Group, European Academy of Allergy and Clinical Immunology. D.W. Cockcroft reports the following research grants in the 36 months prior to manuscript submission: research grant Dept of Medicine University of Saskatchewan (Effect of tiotropium on airway response to allergen); Canadian Society of Allergy and Clinical Immunology (The effect of deep inhalation on mannitol responsiveness); AstraZeneca (A phase 2a double blind randomised parallel group placebo controlled multicentre study to evaluate the effect of AZD8154 administered via nebuliser once daily on allergen-induced inflammation in subjects with mild allergic asthma challenged with inhaled allergen); AllerGen NCE (Methacholine challenge comparison of a jet nebuliser and vibrating mesh nebuliser); Novartis (Inhaled CSJ117 in adult asthmatics with mild atopic asthma). B. Dahlén declares payment to their institution in 2004 for a clinical trial by AstraZeneca, related to the present work; and grants to support the Karolinska Severe Asthma Centre from GlaxoSmithKline and Novartis; consulting fees from Teva, AstraZeneca and Sanofi; and payment for lectures from AstraZeneca and Sanofi, all in the 36 months prior to manuscript submission. W. Fokkens declares grants to their institution from ALK, Mylan, Allergy Therapeutics, GlaxoSmithKline, Sanofi, Novartis and Chordate; consulting fees from Sanofi and Bioinspire; payment or honoraria from Sanofi, GlaxoSmithKline and Novartis; and participation on a data safety monitoring board or advisory board for Lyra, Sanofi and GlaxoSmithKline, all in the 36 months prior to manuscript submission; and that they are Secretary General of the European Rhinologic Society. P. Hellings declares no competing interests. N. Lazarinis declares no competing interests. P.M. O'Byrne reports grants from AstraZeneca, GlaxoSmithKline, Biohaven, Merck, Bayer and Novartis; consulting fees from AstraZeneca, Covis, GlaxoSmithKline, Amgen and Novartis; and payment or honoraria from AstraZeneca, Covis and Novartis, all in the 36 months prior to manuscript submission; and that they are a Section Editor of the European Respiratory Journal. E. Tufvesson declares no competing interests. S. Quirce declares consulting fees and payment or honoraria from GlaxoSmithKline, Sanofi and AstraZeneca; and payment or honoraria from Novartis, Chiesi, Mundipharma and Teva, all in the 36 months prior to manuscript submission. M. Van Maaren declares payment or honoraria from ALK-Abelló, Takeda and CSL Behring, in the 36 months prior to manuscript submission; and an unpaid role as Chairman of the Dutch Society of Allergology and Clinical Immunology since 2020. F. H. de Jongh declares an unpaid role as European Respiratory Society Assessment Director. Z. Diamant reports that until May 2020 they worked as Research Director Respiratory & Allergy at a CRO (QPS-NL), which received funding from biotech and several pharma companies for conduct of phase I–II clinical studies (drug development); and declares consulting fees from ALK-Abelló, AstraZeneca, Antabio, GlaxoSmithKline, HAL Allergy, QPS-NL and Sanofi-Genzyme; and payment or honoraria from BMR, Boehringer Ingelheim, European Forum for Research and Education in Allergy and Airway Diseases (EUFOREA), Merck Sharp & Dohme and Sanofi-Genzyme, all in the 36 months prior to manuscript submission; and unpaid roles as the European Academy of Allergy and Clinical Immunology Asthma Section Chair (2017–2019) and EUFOREA Asthma Expert Panel Chair (since 2020)., (Copyright ©The authors 2022.)

Purpose: Cold air exposure is associated with increased respiratory morbidity and mortality. Repeated inhalation of cold and dry air is considered the cause of the high prevalence of asthma among winter endurance athletes. This study assessed whether a heat- and moisture-exchanging breathing device (HME) attenuates airway responses to high-intensity exercise in sub-zero temperatures among healthy subjects., Methods: Using a randomized cross-over design, 23 healthy trained participants performed a 30-min warm-up followed by a 4-min maximal, self-paced running time trial in - 15 °C, with and without HME. Lung function was assessed pre- and immediately post-trials. Club cell protein (CC-16), 8-isoprostane, and cytokine concentrations were measured in plasma and urine pre- and 60 min post trials. Symptoms were assessed prior to, during, and immediately after each trial in the chamber., Results: HME use attenuated the decrease in forced expiratory volume in 1 s (FEV 1 ) post trials (∆FEV 1 : mean (SD) HME - 0.5 (1.9) % vs. no-HME - 2.7 (2.7) %, p = 0.002). HME also substantially attenuated the median relative increase in plasma-CC16 concentrations (with HME + 27% (interquartile range 9-38) vs no-HME + 121% (55-162), p < 0.001) and reduced airway and general symptom intensity, compared to the trial without HME. No significant changes between trials were detected in urine CC16, 8-isoprostane, or cytokine concentrations., Conclusion: The HME attenuated acute airway responses induced by moderate-to-maximal-intensity exercise in - 15 °C in healthy subjects. Further studies are needed to examine whether this HMEs could constitute primary prevention against asthma in winter endurance athletes., (© 2022. The Author(s).)

Single nucleotide polymorphisms (SNPs) in various genes have been shown to associate with COPD, suggesting a role in disease pathogenesis. Sulfatase modifying factor (SUMF1) is a key modifier in connective tissue remodelling, and we have shown previously that several SNPs in SUMF1 are associated with COPD. The aim of this study was to investigate the association between SUMF1 SNPs and advanced lung function characteristics. Never-, former and current smokers with (n=154) or without (n=405) COPD were genotyped for 21 SNPs in SUMF1 and underwent spirometry, body plethysmography, diffusing capacity of the lung for carbon monoxide ( D LCO ) measurement and impulse oscillometry. Four SNPs (rs793391, rs12634248, rs2819590 and rs304092) showed a significantly decreased odds ratio of having COPD when heterozygous for the variance allele, together with a lower forced expiratory volume in 1 s (FEV 1 ) and FEV 1 /forced vital capacity (FVC) ratio and an impaired peripheral resistance and reactance. Moreover, individuals homozygous for the variance allele of rs3864051 exhibited a strong association to COPD, a lower FEV 1 /FVC, FEV 1 and D LCO , and an impaired peripheral resistance and reactance. Other SNPs (rs4685744, rs2819562, rs2819561 and rs11915920) were instead associated with impaired lung volumes and exhibited a lower FVC, total lung capacity and alveolar volume, in individuals having the variance allele. Several SNPs in the SUMF1 gene are shown to be associated with COPD and impaired lung function. These genetic variants of SUMF1 may cause a deficient sulfation balance in the extracellular matrix of the lung tissue, thereby contributing to the development of COPD., Competing Interests: Conflict of interest: P. Wollmer reports receiving support for the present manuscript from the Swedish Heart and Lung Foundation; payment or honoraria for lectures, presentations, speaker bureaus, manuscript writing or educational events from Chiesi Pharma, outside the submitted work: and a patent issued for a device and method for pulmonary function measurement (no licence). The remaining authors have nothing to disclose., (Copyright ©The authors 2022.)

Background: A subset of individuals with allergic asthma develops a late phase response (LPR) to inhaled allergens, which is characterized by a prolonged airway obstruction, airway inflammation and airway hyperresponsiveness. The aim of this study was to identify changes in the plasma proteome and circulating hematopoietic progenitor cells associated with the LPR following inhaled allergen challenge., Methods: Serial plasma samples from asthmatics undergoing inhaled allergen challenge were analyzed by mass spectrometry and immunosorbent assays. Peripheral blood mononuclear cells were analyzed by flow cytometry. Mass spectrometry data were analyzed using a linear regression to model the relationship between airway obstruction during the LPR and plasma proteome changes. Data from immunosorbent assays were analyzed using linear mixed models., Results: Out of 396 proteins quantified in plasma, 150 showed a statistically significant change 23 h post allergen challenge. Among the most upregulated proteins were three protease inhibitors: alpha-1-antitrypsin, alpha-1-antichymotrypsin and plasma serine protease inhibitor. Altered levels of 13 proteins were associated with the LPR, including increased factor XIII A and decreased von Willebrand factor. No relationship was found between the LPR and changes in the proportions of classical, intermediate, and non-classical monocytes., Conclusions: Allergic reactions to inhaled allergens in asthmatic subjects were associated with changes in a large proportion of the measured plasma proteome, whereof protease inhibitors showed the largest changes, likely to influence the inflammatory response. Many of the proteins altered in relation to the LPR are associated with coagulation, highlighting potential mechanistic targets for future treatments of type-2 asthma., (© 2022. The Author(s).)

Exposure to a cold climate is associated with an increased morbidity and mortality, but the specific mechanisms are largely unknown. People with cardiopulmonary disease and winter endurance athletes are particularly vulnerable. This study aimed to map multiple domains of airway responses to exercise in subzero temperature in healthy individuals.Thirty-one healthy subjects underwent whole-body exposures for 50 minutes on two occasions in an environmental chamber with intermittent moderate-intensity exercise in +10 °C and -10 °C. Lung function, plasma/urine CC16 , and symptoms were investigated before and after exposures.Compared to baseline, exercise in -10 °C decreased FEV 1  (p=0.002), FEV 1 /FVC (p<0.001), and increased R20Hz (p=0.016), with no differences between exposures. Reactance increased after +10 °C (p=0.005), which differed (p=0.042) from a blunted response after exercise in -10 °C. Plasma CC16 increased significantly within exposures, without differences between exposures. Exercise in -10 °C elicited more intense symptoms from the upper airways, compared to +10 °C. Symptoms from the lower airways were few and mild. Short-duration moderate-intensity exercise in -10 °C induces mild symptoms from the lower airways, no lung function decrements or enhanced leakage of biomarkers of airway epithelial injury, and no peripheral bronchodilatation, compared to exercise in +10 °C.

Background: The forced oscillation technique (FOT) provides detailed information about the mechanics of the respiratory system, while requiring minimal co-operation by the patient. FOT may be abnormal in subjects with normal spirometry and appears to be more closely related to airway symptoms. It is, therefore, attractive in epidemiological studies, where a large number of different examinations are made in each subjects in a short period of time. Current technical standards recommend the mean of three consecutive measurements to be used, but there is limited information regarding within-session variability of FOT measurements., Objective: The purpose of this study was to examine the within-session variability in FOT measurements in a large, population-based sample., Methods: We performed three consecutive FOT measurements in 700 subjects using the impulse oscillometry system. The first measurement was compared to the mean of three measurements for resistance at 5 and 20 Hz (R5 and R20, respectively), R5-R20, reactance at 5 Hz (X5) and resonant frequency (f res )., Results: The differences between the first and the mean of three measurements (median, interquartile range) were minimal, for example 0.002, -0.008 to 0.014 kPa L -1  s for R5 and -0.001, -0.008 to 0.005 kPa L -1  s for X5. Findings were numerically similar for men and women as well as for subjects with and without airflow obstruction at spirometry., Conclusions: We conclude that, whereas in clinical situations, three FOT measurements are to be preferred, a single measurement may suffice in epidemiological studies., (© 2021 The Authors. Clinical Physiology and Functional Imaging published by John Wiley & Sons Ltd on behalf of Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

Aim: Very preterm birth may be associated with lung function impairment later in life. It is not known if this is caused by prematurity per se or by associated perinatal events, such as maternal-foetal inflammation and severity of early neonatal lung disease. We assessed these factors in a prospective cohort of very preterm infants followed from birth to middle school age., Methods: In 71 infants with a gestational age of median 27.4 (range 23.9-31.7) weeks, pro-inflammatory and modulatory cytokines were measured in umbilical cord blood and in arterial blood sampled at 6, 24 and 72 h after birth, and cumulated cytokine concentrations were calculated as area under the curve (AUC). At median 12.6 (range 12.3-13.5) years of age, pulmonary function testing was done in 53 children., Results: There was a positive correlation between days on mechanical ventilation and AUC for IL-6 (p = 0.001), IL-8 (p = 0.015) and IL-10 (p = 0.006). Infants with bronchopulmonary dysplasia (BPD; n = 32) had higher AUC for the cytokines IL-6, IL-8 and IL-10 than those without BPD (all p < 0.01). Higher levels of AUC for IL-6 at birth correlated with lower forced expiratory volume in 1 s (p = 0.030) and lower mean expiratory flow rate between 25 and 75% of forced vital capacity (p = 0.034)., Conclusion: Perinatal inflammation, assessed by circulating cytokines in the first three days of life, was associated with BPD and with airway obstruction at 12 years of age., (©2021 The Authors. Acta Paediatrica published by John Wiley & Sons Ltd on behalf of Foundation Acta Paediatrica.)

Airway basal cells are crucial for regeneration of the human lung airway epithelium and are believed to be important contributors to chronic obstructive pulmonary disease (COPD) and other lung disorders. To reveal how basal cells contribute to disease and to discover novel therapeutic targets, these basal cells need to be further characterized. In this study, we optimized a flow cytometry-based cell sorting protocol for primary human airway basal cells dependent on cell size and NGFR (nerve-growth factor receptor) expression. The basal cell population was found to be molecularly and functionally heterogeneous, in contrast to cultured basal cells. In addition, significant differences were found, such as KRT14 expression exclusively existing in cultured cells. Also, colony-forming capacity was significantly increased in cultured cells showing a clonal enrichment in vitro . Next, by single-cell RNA sequencing on primary basal cells from healthy donors and patients with Global Initiative for Chronic Obstructive Lung Disease stage IV COPD, the gene expression revealed a continuum ranging from healthy basal cell signatures to diseased basal cell phenotypes. We identified several upregulated genes that may indicate COPD, such as stress response-related genes GADD45B and AHSA1 , together with with genes involved in the response to hypoxia, such as CITED2 and SOD1 . Taken together, the presence of healthy basal cells in stage IV COPD demonstrates the potential for regeneration through the discovery of novel therapeutic targets. In addition, we show the importance of studying primary basal cells when investigating disease mechanisms as well as for developing future cell-based therapies in the human lung.