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Gill R, Rojas‐Ruiz A, Boucher M, Henry C, Bossé Y. More airway smooth muscle in males versus females in a mouse model of asthma: A blessing in disguise? Exp Physiol 2023; 108:1080-1091. [PMID: 37341687 PMCID: PMC10988431 DOI: 10.1113/ep091236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/06/2023] [Indexed: 06/22/2023]
Abstract
NEW FINDINGS What is the central question of this study? The lung response to inhaled methacholine is reputed to be greater in male than in female mice. The underpinnings of this sex disparity are ill defined. What is the main finding and its importance? We demonstrated that male airways exhibit a greater content of airway smooth muscle than female airways. We also found that, although a more muscular airway tree in males might contribute to their greater responsiveness to inhaled methacholine than females, it might also curb the heterogeneity in small airway narrowing. ABSTRACT Mouse models are helpful in unveiling the mechanisms underlying sex disparities in asthma. In comparison to their female counterparts, male mice are hyperresponsive to inhaled methacholine, a cardinal feature of asthma that contributes to its symptoms. The physiological details and the structural underpinnings of this hyperresponsiveness in males are currently unknown. Herein, BALB/c mice were exposed intranasally to either saline or house dust mite once daily for 10 consecutive days to induce experimental asthma. Twenty-four hours after the last exposure, respiratory mechanics were measured at baseline and after a single dose of inhaled methacholine that was adjusted to trigger the same degree of bronchoconstriction in both sexes (it was twice as high in females). Bronchoalveolar lavages were then collected, and the lungs were processed for histology. House dust mite increased the number of inflammatory cells in bronchoalveolar lavages to the same extent in both sexes (asthma, P = 0.0005; sex, P = 0.96). The methacholine response was also markedly increased by asthma in both sexes (e.g., P = 0.0002 for asthma on the methacholine-induced bronchoconstriction). However, for a well-matched bronchoconstriction between sexes, the increase in hysteresivity, an indicator of airway narrowing heterogeneity, was attenuated in males for both control and asthmatic mice (sex, P = 0.002). The content of airway smooth muscle was not affected by asthma but was greater in males (asthma, P = 0.31; sex, P < 0.0001). These results provide further insights regarding an important sex disparity in mouse models of asthma. The increased amount of airway smooth muscle in males might contribute functionally to their greater methacholine response and, possibly, to their decreased propensity for airway narrowing heterogeneity.
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Affiliation(s)
- Rebecka Gill
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Andrés Rojas‐Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
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Sallé-Lefort S, Miard S, Henry C, Arias-Reyes C, Marcouiller F, Beaulieu MJ, Aubin S, Lechasseur A, Jubinville É, Marsolais D, Morissette MC, Joseph V, Soliz J, Bossé Y, Picard F. Malat1 deficiency prevents hypoxia-induced lung dysfunction by protecting the access to alveoli. Front Physiol 2022; 13:949378. [PMID: 36105289 PMCID: PMC9464821 DOI: 10.3389/fphys.2022.949378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/02/2022] [Indexed: 12/02/2022] Open
Abstract
Hypoxia is common in lung diseases and a potent stimulator of the long non-coding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1). Herein, we investigated the impact of Malat1 on hypoxia-induced lung dysfunction in mice. Malat1-deficient mice and their wild-type littermates were tested after 8 days of normoxia or hypoxia (10% oxygen). Hypoxia decreased elastance of the lung by increasing lung volume and caused in vivo hyperresponsiveness to methacholine without altering the contraction of airway smooth muscle. Malat1 deficiency also modestly decreased lung elastance but only when tested at low lung volumes and without altering lung volume and airway smooth muscle contraction. The in vivo responsiveness to methacholine was also attenuated by Malat1 deficiency, at least when elastance, a readout sensitive to small airway closure, was used to assess the response. More impressively, in vivo hyperresponsiveness to methacholine caused by hypoxia was virtually absent in Malat1-deficient mice, especially when hysteresivity, a readout sensitive to small airway narrowing heterogeneity, was used to assess the response. Malat1 deficiency also increased the coefficient of oxygen extraction and decreased ventilation in conscious mice, suggesting improvements in gas exchange and in clinical signs of respiratory distress during natural breathing. Combined with a lower elastance at low lung volumes at baseline, as well as a decreased propensity for small airway closure and narrowing heterogeneity during a methacholine challenge, these findings represent compelling evidence suggesting that the lack of Malat1 protects the access to alveoli for air entering the lung.
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Affiliation(s)
- Sandrine Sallé-Lefort
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Pharmacy, Université Laval, Quebec, QC, Canada
| | - Stéphanie Miard
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Cyndi Henry
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Christian Arias-Reyes
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - François Marcouiller
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Marie-Josée Beaulieu
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Sophie Aubin
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Ariane Lechasseur
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Éric Jubinville
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - David Marsolais
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Mathieu C. Morissette
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Vincent Joseph
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Jorge Soliz
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Ynuk Bossé
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
- *Correspondence: Ynuk Bossé, ; Frédéric Picard,
| | - Frédéric Picard
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Pharmacy, Université Laval, Quebec, QC, Canada
- *Correspondence: Ynuk Bossé, ; Frédéric Picard,
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Chevrier S, Abdulnour J, Saint-Pierre MD. Predictors of methacholine challenge testing results in subjects without airflow obstruction. J Asthma 2021; 59:2060-2068. [PMID: 34570662 DOI: 10.1080/02770903.2021.1986838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Methacholine challenge testing (MCT) is considered when asthma remains clinically suspected despite normal spirometry. Few studies have attempted to determine the predictive factors of MCT results. We aimed to establish which demographic data, clinical symptoms, pulmonary function testing results, and laboratory values were associated with abnormal MCT (provocation concentration causing a 20% decrease in FEV1 (PC20) ≤ 16 mg/mL) in subjects without airflow obstruction on spirometry. METHODS All patients who completed MCT at Montfort Hospital between January 1st, 2016 and December 31st, 2018 were identified. Subjects with a reduced FEV1/FVC ratio were excluded. We used Pearson's chi-squared test and point-biserial correlation method to determine which variables had a significant relationship (p < 0.05) with MCT results. RESULTS 23.3% of patients who underwent MCT had airflow limitation. In the 1126 subjects with a normal FEV1/FVC ratio, PC20 ≤ 16 mg/mL was found in 13.0%. Younger age, female gender, body mass index ≥ 40, and reported wheezing were factors associated with increased probability of airway hyper responsiveness. Lower FEV1, significant improvement of the FEV1 post-bronchodilator, reduced FEF25%-75%, greater FEF25%-75% reversibility, airway resistance measurements above the upper limit of normal, and increased blood eosinophil counts were predictive of abnormal MCT. CONCLUSIONS Only 13.0% of patients referred for MCT had a PC20 ≤ 16 mg/mL when the FEV1/FVC ratio was normal, highlighting the need to further define in which individuals this test is truly warranted. Further investigation is required to develop an easy-to-use and validated prediction model in order to better understand patients' pretest probability of abnormal MCT.
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Affiliation(s)
| | - Joseph Abdulnour
- Institut du Savoir Montfort, Ottawa, ON, Canada.,Department of Performance and Decision Support, Montfort Hospital, Ottawa, ON, Canada
| | - Mathieu D Saint-Pierre
- University of Ottawa, Faculty of Medicine, Ottawa, ON, Canada.,Institut du Savoir Montfort, Ottawa, ON, Canada.,Division of Respirology, Montfort Hospital, Ottawa, ON, Canada
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4
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Liu Y, Zhang L, Li HL, Liang BM, Wang J, Zhang X, Chen ZH, Zhang HP, Xie M, Wang L, Wang G, Oliver BG. Small Airway Dysfunction in Asthma Is Associated with Perceived Respiratory Symptoms, Non-Type 2 Airway Inflammation, and Poor Responses to Therapy. Respiration 2021; 100:767-779. [PMID: 33895739 DOI: 10.1159/000515328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 02/15/2021] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Emerging evidence has indicated that small airway dysfunction (SAD) contributes to the clinical expression of asthma. OBJECTIVES The aim of the study was to explore the relationships of SAD assessed by forced expiratory flow between 25 and 75% (FEF25-75%), with clinical and inflammatory profile and treatment responsiveness in asthma. METHOD In study I, dyspnea intensity (Borg scale), chest tightness, wheezing and cough (visual analog scales, VASs), and pre- and post-methacholine challenge testing (MCT) were analyzed in asthma patients with SAD and non-SAD. In study II, asthma subjects with SAD and non-SAD underwent sputum induction, and inflammatory mediators in sputum were detected. Asthma patients with SAD and non-SAD receiving fixed treatments were prospectively followed up for 4 weeks in study III. Spirometry, Asthma Control Questionnaire (ACQ), and Asthma Control Test (ACT) were carried out to define treatment responsiveness. RESULTS SAD subjects had more elevated ΔVAS for dyspnea (p = 0.027) and chest tightness (p = 0.032) after MCT. Asthma patients with SAD had significantly elevated interferon (IFN)-γ in sputum (p < 0.05), and Spearman partial correlation found FEF25-75% significantly related to IFN-γ and interleukin-8 (both having p < 0.05). Furthermore, multivariable regression analysis indicated SAD was significantly associated with worse treatment responses (decrease in ACQ ≥0.5 and increase in ACT ≥3) (p = 0.022 and p = 0.032). CONCLUSIONS This study indicates that SAD in asthma predisposes patients to greater dyspnea intensity and chest tightness during bronchoconstriction. SAD patients with asthma are characterized by non-type 2 inflammation that may account for poor responsiveness to therapy.
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Affiliation(s)
- Ying Liu
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Li Zhang
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China.,Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Hong Lin Li
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Bin Miao Liang
- Department of Respiratory and Critical Care Medicine, Clinical Research Center for Respiratory Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Ji Wang
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China.,Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Xin Zhang
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China.,Department of Respiratory and Critical Care Medicine, Clinical Research Center for Respiratory Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Zhi Hong Chen
- Shanghai Institute of Respiratory Disease, Respiratory Division of Zhongshan Hospital, Fudan University, Shanghai, China
| | - Hong Ping Zhang
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Min Xie
- Department of Respiratory and Critical Care Medicine, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Wang
- Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Gang Wang
- Department of Respiratory and Critical Care Medicine, Clinical Research Center for Respiratory Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Brian G Oliver
- School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia.,Respiratory Cellular and Molecular Biology, Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia
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5
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Tonga KO, Chapman DG, Farah CS, Oliver BG, Zimmermann SC, Milne S, Sanai F, Jetmalani K, Berend N, Thamrin C, King GG. Reduced lung elastic recoil and fixed airflow obstruction in asthma. Respirology 2019; 25:613-619. [PMID: 31482693 DOI: 10.1111/resp.13688] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/01/2019] [Accepted: 08/07/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE Fixed airflow obstruction (FAO) in asthma occurs despite optimal inhaled treatment and no smoking history, and remains a significant problem, particularly with increasing age and duration of asthma. Increased lung compliance and loss of lung elastic recoil has been observed in older people with asthma, but their link to FAO has not been established. We determined the relationship between abnormal lung elasticity and airflow obstruction in asthma. METHODS Non-smoking asthmatic subjects aged >40 years, treated with 2 months of high-dose inhaled corticosteroid/long-acting beta-agonist (ICS/LABA), had FAO measured by spirometry, and respiratory system resistance at 5 Hz (Rrs5 ) and respiratory system reactance at 5 Hz (Xrs5 ) measured by forced oscillation technique. Lung compliance (K) and elastic recoil (B/A) were calculated from pressure-volume curves measured by an oesophageal balloon. Linear correlations between K and B/A, and forced expiratory volume in 1 s/forced vital capacity (FEV1 /FVC), Rrs5 and Xrs5 were assessed. RESULTS Eighteen subjects (11 males; mean ± SD age: 64 ± 8 years, asthma duration: 39 ± 22 years) had moderate FAO measured by spirometry ((mean ± SD z-score) post-bronchodilator FEV1 : -2.2 ± 0.5, FVC: -0.7 ± 1.0, FEV1 /FVC: -2.6 ± 0.7) and by increased Rrs5 (median (IQR) z-score) 2.7 (1.9 to 3.2) and decreased Xrs5 : -4.1(-2.4 to -7.3). Lung compliance (K) was increased in 9 of 18 subjects and lung elastic recoil (B/A) reduced in 5 of 18 subjects. FEV1 /FVC correlated negatively with K (rs = -0.60, P = 0.008) and Rrs5 correlated negatively with B/A (rs = -0.52, P = 0.026), independent of age. Xrs5 did not correlate with lung elasticity indices. CONCLUSION Increased lung compliance and loss of elastic recoil relate to airflow obstruction in older non-smoking asthmatic subjects, independent of ageing. Thus, structural lung tissue changes may contribute to persistent, steroid-resistant airflow obstruction. CLINICAL TRIAL REGISTRATION ACTRN126150000985583 at anzctr.org.au (UTN: U1111-1156-2795).
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Affiliation(s)
- Katrina O Tonga
- The Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,The Department of Respiratory Medicine, Concord Hospital, Sydney, NSW, Australia.,The Department of Thoracic and Lung Transplant Medicine, St Vincent's Hospital, Sydney, NSW, Australia.,St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - David G Chapman
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Discipline of Medical Sciences, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Claude S Farah
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,The Department of Respiratory Medicine, Concord Hospital, Sydney, NSW, Australia.,Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Brian G Oliver
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Discipline of Medical Sciences, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Sabine C Zimmermann
- The Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,The Department of Respiratory Medicine, Concord Hospital, Sydney, NSW, Australia
| | - Stephen Milne
- The Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,The Department of Respiratory Medicine, Concord Hospital, Sydney, NSW, Australia
| | - Farid Sanai
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Discipline of Medical Sciences, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Kanika Jetmalani
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia
| | - Norbert Berend
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia.,Respiratory Research Group, The George Institute for Global Health, Sydney, NSW, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Gregory G King
- The Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,NHMRC Centre of Excellence in Severe Asthma, Newcastle, NSW, Australia
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6
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Tonga KO, Berend N, Thamrin C, Farah CS, Jetmalani K, Chapman DG, King GG. Lung elastic recoil and ventilation heterogeneity of diffusion-dependent airways in older people with asthma and fixed airflow obstruction. Eur Respir J 2019; 53:13993003.01028-2018. [PMID: 30578400 DOI: 10.1183/13993003.01028-2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 12/13/2018] [Indexed: 11/05/2022]
Affiliation(s)
- Katrina O Tonga
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia.,The University of Sydney, School of Medicine, Faculty of Medicine and Health, Sydney, Australia.,Dept of Thoracic and Transplant Medicine, St Vincent's Hospital, Sydney, Australia.,The University of New South Wales, Faculty of Medicine, Sydney, Australia
| | - Norbert Berend
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,The University of Sydney, School of Medicine, Faculty of Medicine and Health, Sydney, Australia.,The University of New South Wales, Faculty of Medicine, Sydney, Australia.,The George Institute for Global Health, Sydney, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,The University of Sydney, School of Medicine, Faculty of Medicine and Health, Sydney, Australia
| | - Claude S Farah
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia.,The University of Sydney, School of Medicine, Faculty of Medicine and Health, Sydney, Australia.,Macquarie University, Faculty of Medicine and Health Sciences, Sydney, Australia
| | - Kanika Jetmalani
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
| | - David G Chapman
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Translational Airways Group, School of Life Sciences, University of Technology Sydney, Sydney, Australia
| | - Gregory G King
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,The University of Sydney, School of Medicine, Faculty of Medicine and Health, Sydney, Australia.,NHMRC Centre of Excellence in Severe Asthma, New Lambton Heights, Australia
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7
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Zimmermann SC, Tonga KO, Thamrin C. Dismantling airway disease with the use of new pulmonary function indices. Eur Respir Rev 2019; 28:28/151/180122. [PMID: 30918023 PMCID: PMC9488242 DOI: 10.1183/16000617.0122-2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 02/15/2019] [Indexed: 11/27/2022] Open
Abstract
We are currently limited in our abilities to diagnose, monitor disease status and manage chronic airway disease like asthma and chronic obstructive pulmonary disease (COPD). Conventional lung function measures often poorly reflect patient symptoms or are insensitive to changes, particularly in the small airways where disease may originate or manifest. Novel pulmonary function tests are becoming available which help us better characterise and understand chronic airway disease, and their translation and adoption from the research arena would potentially enable individualised patient care. In this article, we aim to describe two emerging lung function tests yielding novel pulmonary function indices, the forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW). With a particular focus on asthma and COPD, this article demonstrates how chronic airway disease mechanisms have been dismantled with the use of the FOT and MBNW. We describe their ability to assess detailed pulmonary mechanics for diagnostic and management purposes including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring. The current limitations of both tests, as well as open questions/directions for further research, are also discussed. Spirometry is used to diagnose and manage airway disease such as asthma and COPD, but relates poorly to symptoms, lacks sensitivity and is effort dependent. FOT and MBNW are emerging clinical lung function tests that help us dismantle disease mechanisms.http://ow.ly/nM0G30nS6Ct
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Affiliation(s)
- Sabine C Zimmermann
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Sydney Medical School Northern, The University of Sydney, Sydney, Australia.,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Katrina O Tonga
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Sydney Medical School Northern, The University of Sydney, Sydney, Australia.,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Thoracic and Transplant Medicine, St Vincent's Hospital, Sydney, Australia.,Faculty of Medicine, The University of New South Wales, Sydney, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia .,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
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8
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Postma DS, Brightling C, Baldi S, Van den Berge M, Fabbri LM, Gagnatelli A, Papi A, Van der Molen T, Rabe KF, Siddiqui S, Singh D, Nicolini G, Kraft M. Exploring the relevance and extent of small airways dysfunction in asthma (ATLANTIS): baseline data from a prospective cohort study. THE LANCET RESPIRATORY MEDICINE 2019; 7:402-416. [PMID: 30876830 DOI: 10.1016/s2213-2600(19)30049-9] [Citation(s) in RCA: 199] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/26/2018] [Accepted: 12/18/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Small airways dysfunction (SAD) is well recognised in asthma, yet its role in the severity and control of asthma is unclear. This study aimed to assess which combination of biomarkers, physiological tests, and imaging markers best measure the presence and extent of SAD in patients with asthma. METHODS In this baseline assessment of a multinational prospective cohort study (the Assessment of Small Airways Involvement in Asthma [ATLANTIS] study), we recruited participants with and without asthma (defined as Global Initiative for Asthma severity stages 1-5) from general practices, the databases of chest physicians, and advertisements at 29 centres across nine countries (Brazil, China, Germany, Italy, Spain, the Netherlands, the UK, the USA, and Canada). All participants were aged 18-65 years, and participants with asthma had received a clinical diagnosis of asthma more than 6 months ago that had been confirmed by a chest physician. This diagnosis required support by objective evidence at baseline or during the past 5 years, which could be: positive airway hyperresponsiveness to methacholine, positive reversibility (a change in FEV1 ≥12% and ≥200 mL within 30 min) after treatment with 400 μg of salbutamol in a metered-dose inhaler with or without a spacer, variability in peak expiratory flow of more than 20% (measured over 7 days), or documented reversibility after a cycle (eg, 4 weeks) of maintenance anti-asthma treatment. The inclusion criteria also required that patients had stable asthma on any previous regular asthma treatment (including so-called rescue β2-agonists alone) at a stable dose for more than 8 weeks before baseline and had smoked for a maximum of 10 pack-years in their lifetime. Control group participants were recruited by advertisements; these participants were aged 18-65 years, had no respiratory symptoms compatible with asthma or chronic obstructive pulmonary disease, normal spirometry, and normal airways responsiveness, and had smoked for a maximum of 10 pack-years. We assessed all participants with spirometry, body plethysmography, impulse oscillometry, multiple breath nitrogen washout, CT (in selected participants), and questionnaires about asthma control, asthma-related quality of life (both in participants with asthma only), and health status. We applied structural equation modelling in participants with asthma to assess the contribution of all physiological and CT variables to SAD, from which we defined clinical SAD and CT SAD scores. We then classified patients with asthma into SAD groups with model-based clustering, and we compared asthma severity, control, and health-care use during the past year by SAD score and by SAD group. This trial is registered with ClinicalTrials.gov, number NCT02123667. FINDINGS Between June 30, 2014, and March 3, 2017, we recruited and evaluated 773 participants with asthma and 99 control participants. All physiological measures contributed to the clinical SAD model with the structural equation modelling analysis. The prevalence of SAD in asthma was dependent on the measure used; we found the lowest prevalence of SAD associated with acinar airway ventilation heterogeneity (Sacin), an outcome determined by multiple breath nitrogen washout that reflects ventilation heterogeneity in the most peripheral, pre-acinar or acinar airways. Impulse oscillometry and spirometry results, which were used to assess dysfunction of small-sized to mid-sized airways, contributed most to the clinical SAD score and differed between the two SAD groups. Participants in clinical SAD group 1 (n=452) had milder SAD than group 2 and comparable multiple breath nitrogen washout Sacin to control participants. Participants in clinical SAD group 2 (n=312) had abnormal physiological SAD results relative to group 1, particularly their impulse oscillometry and spirometry measurements, and group 2 participants also had more severe asthma (with regard to asthma control, treatments, exacerbations, and quality of life) than group 1. Clinical SAD scores were higher (indicating more severe SAD) in group 2 than group 1, and we found that these scores were related to asthma control, severity, and exacerbations. We found no correlation between clinical SAD and CT SAD scores. INTERPRETATION SAD is a complex and silent signature of asthma that is likely to be directly or indirectly captured by combinations of physiological tests, such as spirometry, body plethysmography, impulse oscillometry, and multiple breath nitrogen washout. SAD is present across patients with all severities of asthma, but it is particularly prevalent in severe disease. The clinical classification of SAD into two groups (a milder and a more severe group) by use of impulse oscillometry and spirometry, which are easy to use, is meaningful given its association with GINA severity stages, asthma control, quality of life, and exacerbations. FUNDING Chiesi Farmaceutici SpA.
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Affiliation(s)
- Dirkje S Postma
- Department of Pulmonology, Groningen Research Institute for Asthma and COPD, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
| | - Chris Brightling
- Institute for Lung Health, National Institute for Health Research Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Simonetta Baldi
- Institute for Lung Health, National Institute for Health Research Biomedical Research Centre, University of Leicester, Leicester, UK; Department of Global Clinical Development, Chiesi SAS, Bois-Colombes, France
| | - Maarten Van den Berge
- Department of Pulmonology, Groningen Research Institute for Asthma and COPD, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Leonardo M Fabbri
- Research Centre on Asthma and COPD, University of Ferrara, Ferrara, Italy; COPD Centre, Sahlgrenska University Hospital, Gothenburg, Sweden
| | | | - Alberto Papi
- Research Centre on Asthma and COPD, University of Ferrara, Ferrara, Italy
| | - Thys Van der Molen
- Department of General Practice, Groningen Research Institute for Asthma and COPD, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Klaus F Rabe
- LungenClinic, Grosshansdorf, Germany; Department of Medicine, Christian Albrechts University, Kiel, Germany; Airway Research Center North, German Center for Lung Research (DZL), Hannover, Germany
| | - Salman Siddiqui
- Institute for Lung Health, National Institute for Health Research Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Dave Singh
- Centre for Respiratory Medicine and Allergy, University Hospital of South Manchester, University of Manchester, Manchester, UK
| | - Gabriele Nicolini
- Department of Global Clinical Development, Chiesi Farmaceutici SpA, Parma, Italy
| | - Monica Kraft
- University of Arizona College of Medicine, Department of Medicine, Tucson, AZ, USA
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9
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Kaminsky DA, Chapman DG, Holbrook JT, Henderson RJ, Sugar EA, Mastronarde J, Teague WG, Busk M, Sumino K, Dixon AE, Wise RA, Irvin CG. Older age and obesity are associated with increased airway closure in response to methacholine in patients with asthma. Respirology 2019; 24:638-645. [PMID: 30838750 DOI: 10.1111/resp.13496] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 11/29/2018] [Accepted: 01/02/2019] [Indexed: 01/31/2023]
Abstract
BACKGROUND AND OBJECTIVE The reduction of forced expiratory volume in 1 s (FEV1 ) in response to methacholine challenge in asthma may reflect two components: airway narrowing, assessed by the change in FEV1 /forced vital capacity (FVC), and airway closure, assessed by the change in FVC. The purpose of this study was to determine the degree and determinants of airway closure in response to methacholine in a large group of asthmatic patients participating in studies conducted by the American Lung Association-Airways Clinical Research Centers (ALA-ACRC). METHODS We used the methacholine challenge data from participants in five studies of the ALA-ACRC to determine the closing index, defined as the contribution of airway closure to the decrease in FEV1 , and calculated as %ΔFVC/%ΔFEV1 . RESULTS There were a total of 936 participants with asthma, among whom the median closing index was 0.67 relative to that of a published healthy population of 0.54. A higher closing index was associated with increased age (10-year increments) (0.04, 95% CI = 0.02, 0.05, P < 0.005) and obesity (0.07, 95% CI = 0.03, 0.10, P < 0.001). There was no association between the closing index and asthma control. CONCLUSION Our findings confirm that airway closure in response to methacholine occurs in a large, diverse population of asthmatic participants, and that increased airway closure is associated with older age and obesity. These findings suggest that therapies targeting airway closure may be important in patients with a high closing index.
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Affiliation(s)
- David A Kaminsky
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - David G Chapman
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA.,Translational Airways Group, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, Sydney, NSW, Australia
| | - Janet T Holbrook
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Robert J Henderson
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Elizabeth A Sugar
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - John Mastronarde
- Division of Pulmonary Medicine, Providence Portland Medical Center, Portland, OR, USA
| | - William G Teague
- Division of Pediatric Respiratory Medicine and Allergy, University of Virginia, Charlottesville, VA, USA
| | - Michael Busk
- Division of Pulmonary Medicine, St. Vincent Hospital and Health Care Center, Inc., Indianapolis, IN, USA
| | - Kaharu Sumino
- Division of Pulmonary and Critical Care Medicine, Washington University, St. Louis, MO, USA
| | - Anne E Dixon
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Robert A Wise
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Charles G Irvin
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA
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10
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Htun C, Pope A, Lahzami S, Luo D, Schoeffel RE, Farrow CE, Phillips CL, Robinson PD, King GG. Contribution of peripheral airway function to changes in FEV 1/FVC and RV/TLC with aging. J Appl Physiol (1985) 2018; 125:1378-1383. [PMID: 30138079 DOI: 10.1152/japplphysiol.00114.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multiple breath nitrogen washout (MBNW) indices provide insight into ventilation heterogeneity globally [lung clearance index (LCI)] and within acinar (Sacin) and conducting (Scond) airways. Normal aging leads to an accelerated deterioration of Sacin in older adults, but little is known about the contribution of peripheral airway function to changes in pulmonary function indices reflecting expiratory airflow [forced expiratory volume in one second (FEV1)/forced vital capacity (FVC)] and gas trapping [residual volume (RV)/total lung capacity (TLC)] with aging. We aimed to examine associations between MBNW and FEV1/FVC as well as RV/TLC in healthy adults, and to determine if these relationships differ in older (≥50 yr) versus younger subjects (<50 yr). Seventy-nine healthy adult volunteers aged 23-89 yr with no cardiac or respiratory disease and a smoking history of <5 pack-years underwent spirometry, plethysmography, and MBNW. After adjustment for sex, height, and body mass index, the following relationships were present across the entire cohort: Sacin was inversely related to FEV1/FVC (R2 = 0.22, P < 0.001); Sacin and Scond were positively related to RV/TLC (R2 = 0.53, P < 0.001); on separate analyses, the relationship between Sacin and FEV1/FVC was strongest in the older group (R2 = 0.20, P = 0.003) but markedly weaker in the younger group (R2 = 0.09, P = 0.04); and Sacin and Scond were related to RV/TLC in older (R2 = 0.20, P = 0.003) but not younger subgroups. No relationships were observed between LCI and FEV1/FVC or RV/TLC. Changes in FEV1/FVC and RV/TLC are at least in part due to changes in peripheral airway function with aging. Further studies of the relationships between MBNW and standard pulmonary function indices may prove useful for their combined application and interpretation in obstructive airways disease. NEW & NOTEWORTHY This study explores associations between multiple breath nitrogen washout (MBNW) and standard pulmonary function indices reflecting expiratory airflow [forced expiratory volume in one second (FEV1)/forced vital capacity (FVC)] and gas trapping [residual volume (RV)/total lung capacity (TLC)] in healthy adults across a wide range of ages. We have demonstrated statistically significant relationships between MBNW and FEV1/FVC as well as RV/TLC. These findings provide novel evidence of the contribution of peripheral airway function to changes in standard pulmonary function indices with aging.
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Affiliation(s)
- Christopher Htun
- The Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia.,Northern Clinical School, The University of Sydney , St. Leonards, NSW , Australia.,Department of Respiratory and Sleep Medicine, Royal North Shore Hospital , St. Leonards, NSW , Australia
| | - Alun Pope
- Statistical Consulting Service, The University of Sydney , Sydney, NSW , Australia
| | | | - Darren Luo
- The Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia
| | - Robin E Schoeffel
- Department of Respiratory and Sleep Medicine, Royal North Shore Hospital , St. Leonards, NSW , Australia
| | - Catherine E Farrow
- The Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia
| | - Craig L Phillips
- The Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia.,Northern Clinical School, The University of Sydney , St. Leonards, NSW , Australia.,Department of Respiratory and Sleep Medicine, Royal North Shore Hospital , St. Leonards, NSW , Australia
| | - Paul D Robinson
- The Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia.,Department of Respiratory Medicine, The Children's Hospital at Westmead , Westmead, NSW , Australia.,Discipline of Paediatrics and Child Health, The University of Sydney , Sydney, NSW , Australia
| | - Gregory G King
- The Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW, Australia.,Northern Clinical School, The University of Sydney , St. Leonards, NSW , Australia.,Department of Respiratory and Sleep Medicine, Royal North Shore Hospital , St. Leonards, NSW , Australia.,National Health and Medical Research Council Centre of Excellence in Severe Asthma, New Lambton, NSW, Australia
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11
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Chapman DG, King GG. Potential clinical utility for the multiple breath nitrogen washout. Respirology 2018; 23:729-730. [PMID: 29774964 DOI: 10.1111/resp.13326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 11/29/2022]
Affiliation(s)
- David G Chapman
- Molecular Biosciences Research Team, School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia.,The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Gregory G King
- The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.,Centre of Research Excellence in Severe Asthma, Hunter Medical Research Institute, New Lambton, NSW, Australia
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12
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King GG, Thamrin C. Complex lung function in severe asthma: seeing is believing. Eur Respir J 2018; 48:294-6. [PMID: 27478183 DOI: 10.1183/13993003.01120-2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 06/13/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Gregory G King
- Woolcock Institute of Medical Research, The University of Sydney, Australia Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, Australia NHMRC Centre of Excellence in Severe Asthma
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, The University of Sydney, Australia
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13
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Gazzola M, Mailhot-Larouche S, Beucher C, Bossé Y. The underlying physiological mechanisms whereby anticholinergics alleviate asthma. Can J Physiol Pharmacol 2018; 96:433-441. [PMID: 29414243 DOI: 10.1139/cjpp-2017-0448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The mechanisms whereby anticholinergics improve asthma outcomes, such as lung function, symptoms, and rate of exacerbation, can be numerous. The most obvious is by affecting the contraction of airway smooth muscle (ASM). The acetylcholine released from the cholinergic nerves is the most important bronchoconstrictor that sets the baseline degree of contractile activation of ASM in healthy individuals. Although the degree of ASM's contractile activation can also be fine-tuned by a plethora of other bronchoconstrictors and bronchodilators in asthma, blocking the ceaseless effect of acetylcholine on ASM by anticholinergics reduces, at any given moment, the overall degree of contractile activation. Because the relationships that exist between the degree of contractile activation, ASM force, ASM shortening, airway narrowing, airflow resistance, and respiratory resistance are not linear, small decreases in the contractile activation of ASM can be greatly amplified and thus translate into important benefits to a patient's well-being. Plus, many inflammatory and remodeling features that are often found in asthmatic lungs synergize with the contractile activation of ASM to increase respiratory resistance. This review recalls that the proven effectiveness of anticholinergics in the treatment of asthma could be merely attributed to a small reduction in the contractile activation of ASM.
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Affiliation(s)
- Morgan Gazzola
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Samuel Mailhot-Larouche
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Clémentine Beucher
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Ynuk Bossé
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
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14
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King GG, James A, Harkness L, Wark PAB. Pathophysiology of severe asthma: We've only just started. Respirology 2018; 23:262-271. [PMID: 29316003 DOI: 10.1111/resp.13251] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 11/14/2017] [Accepted: 12/07/2017] [Indexed: 12/01/2022]
Abstract
Severe asthma is defined by the high treatment requirements to partly or fully control the clinical manifestations of disease. It remains a problem worldwide with a large burden for individuals and health services. The key to improving targeted treatments, reducing disease burden and improving patient outcomes is a better understanding of the pathophysiology and mechanisms of severe disease. The heterogeneity, complexity and difficulties in undertaking clinical studies in severe asthma remain challenges to achieving better understanding and better outcomes. In this review, we focus on the structural, mechanical and inflammatory abnormalities that are relevant in severe asthma.
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Affiliation(s)
- Gregory G King
- NHMRC Centre for Excellence in Severe Asthma, Newcastle, NSW, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Alan James
- NHMRC Centre for Excellence in Severe Asthma, Newcastle, NSW, Australia.,Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia.,School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia
| | - Louise Harkness
- NHMRC Centre for Excellence in Severe Asthma, Newcastle, NSW, Australia.,The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Peter A B Wark
- NHMRC Centre for Excellence in Severe Asthma, Newcastle, NSW, Australia.,Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia.,Department of Respiratory Medicine, John Hunter Hospital, Newcastle, NSW, Australia
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15
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Lui JK, Lutchen KR. The role of heterogeneity in asthma: a structure-to-function perspective. Clin Transl Med 2017; 6:29. [PMID: 28776171 PMCID: PMC5543015 DOI: 10.1186/s40169-017-0159-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/26/2017] [Indexed: 02/07/2023] Open
Abstract
A number of methods have evolved through the years in probing the dysfunction that impacts mechanics and ventilation in asthma. What has been consistently found is the notion of heterogeneity that is not only captured in the frequency dependence of lung mechanics measurements but also rendered on imaging as patchy diffuse areas of ventilation defects. The degree of heterogeneity has been linked to airway hyperresponsiveness, a hallmark feature of asthma. How these heterogeneous constriction patterns lead to functional impairment in asthma have only been recently explored using computational airway tree models. By synthesizing measurements of lung mechanics and advances in imaging, computational airway tree models serve as a powerful engine to accelerate our understanding of the physiologic changes that occur in asthma. This review will be focused on the current state of investigational work on the role of heterogeneity in asthma, specifically exploring the structural and functional relationships.
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Affiliation(s)
- Justin K. Lui
- Department of Medicine, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Kenneth R. Lutchen
- Department of Biomedical Engineering, Boston University, Boston, MA 02215 USA
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16
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Tonga KO, Robinson PD, Farah CS, King GG, Thamrin C. In vitro and in vivo functional residual capacity comparisons between multiple-breath nitrogen washout devices. ERJ Open Res 2017; 3:00011-2017. [PMID: 29204436 PMCID: PMC5703358 DOI: 10.1183/23120541.00011-2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/23/2017] [Indexed: 11/25/2022] Open
Abstract
Functional residual capacity (FRC) accuracy is essential for deriving multiple-breath nitrogen washout (MBNW) indices, and is the basis for device validation. Few studies have compared existing MBNW devices. We evaluated in vitro and in vivo FRC using two commercial MBNW devices, the Exhalyzer D (EM) and the EasyOne Pro LAB (ndd), and an in-house device (Woolcock in-house device, WIMR). FRC measurements were performed using a novel syringe-based lung model and in adults (20 healthy and nine with asthma), followed by plethysmography (FRCpleth). The data were analysed using device-specific software. Following the results seen with ndd, we also compared its standard clinical software (ndd v.2.00) with a recent upgrade (ndd v.2.01). WIMR and EM fulfilled formal in vitro FRC validation recommendations (>95% of FRC within 5% of known volume). Ndd v.2.00 underestimated in vitro FRC by >20%. Reanalysis using ndd v.2.01 reduced this to 11%, with 36% of measurements ≤5%. In vivo differences from FRCpleth (mean±sd) were 4.4±13.1%, 3.3±11.8%, −20.6±11% (p<0.0001) and −10.5±10.9% (p=0.005) using WIMR, EM, ndd v.2.00 and ndd v.2.01, respectively. Direct device comparison highlighted important differences in measurement accuracy. FRC discrepancies between devices were larger in vivo, compared to in vitro results; however, the pattern of difference was similar. These results represent progress in ongoing standardisation efforts. Multiple-breath washout devices are not yet comparablehttp://ow.ly/bB7b30eAs0c
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Affiliation(s)
- Katrina O Tonga
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia
| | - Paul D Robinson
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia
| | - Claude S Farah
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia
| | - Greg G King
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
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17
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Farrow CE, Salome CM, Harris BE, Bailey DL, Berend N, King GG. Peripheral ventilation heterogeneity determines the extent of bronchoconstriction in asthma. J Appl Physiol (1985) 2017; 123:1188-1194. [PMID: 28798203 DOI: 10.1152/japplphysiol.00640.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/08/2017] [Accepted: 08/08/2017] [Indexed: 11/22/2022] Open
Abstract
In asthma, bronchoconstriction causes topographically heterogeneous airway narrowing, as measured by three-dimensional ventilation imaging. Computation modeling suggests that peripheral airway dysfunction is a potential determinant of acute airway narrowing measured by imaging. We hypothesized that the development of low-ventilation regions measured topographically by three-dimensional imaging after bronchoconstriction is predicted by peripheral airway function. Fourteen asthmatic subjects underwent ventilation single-photon-emission computed tomography/computed tomography scan imaging before and after methacholine challenge. One-liter breaths of Technegas were inhaled from functional residual capacity in upright posture before supine scanning. The lung regions with the lowest ventilation (Ventlow) were calculated using a thresholding method and expressed as a percentage of total ventilation (Venttotal). Multiple-breath nitrogen washout was used to measure diffusion-dependent and convection-dependent ventilation heterogeneity (Sacin and Scond, respectively) and lung clearance index (LCI), before and after challenge. Forced expiratory volume in 1 s (FEV1) was 87.6 ± 15.8% predicted, and seven subjects had airway hyperresponsiveness. Ventlow at baseline was unrelated to spirometry or multiple-breath nitrogen washout indices. Methacholine challenge decreased FEV1 by 23 ± 5% of baseline while Ventlow increased from 21.5 ± 2.3%Venttotal to 26.3 ± 6.7%Venttotal (P = 0.03). The change in Ventlow was predicted by baseline Sacin (rs = 0.60, P = 0.03) and by LCI (rs = 0.70, P = 0.006) but not by Scond (rs = 0.30, P = 0.30). The development of low-ventilation lung units in three-dimensional ventilation imaging is predicted by ventilation heterogeneity in diffusion-dependent airways. This relationship suggests that acinar ventilation heterogeneity in asthma may be of mechanistic importance in terms of bronchoconstriction and airway narrowing.NEW & NOTEWORTHY Using ventilation SPECT/CT imaging in asthmatics, we show induced bronchoconstriction leads to the development of areas of low ventilation. Furthermore, the relative volume of the low-ventilation regions was predicted by ventilation heterogeneity in diffusion-dependent acinar airways. This suggests that the pattern of regional airway narrowing in asthma is determined by acinar airway function.
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Affiliation(s)
- Catherine E Farrow
- Woolcock Institute of Medical Research, The University of Sydney, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards Australia
| | - Cheryl M Salome
- Woolcock Institute of Medical Research, The University of Sydney, Australia
| | - Benjamin E Harris
- Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards Australia
| | - Dale L Bailey
- Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards Australia.,Department of Nuclear Medicine, Royal North Shore Hospital, St. Leonards Australia; and
| | - Norbert Berend
- Woolcock Institute of Medical Research, The University of Sydney, Australia.,Department of Respiratory Research, George Institute of Global Health, Australia
| | - Gregory G King
- Woolcock Institute of Medical Research, The University of Sydney, Australia; .,Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards Australia.,NHMRC Centre of Excellence in Severe Asthma, The University of Sydney, Australia
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18
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Gazzola M, Lortie K, Henry C, Mailhot-Larouche S, Chapman DG, Couture C, Seow CY, Paré PD, King GG, Boulet LP, Bossé Y. Airway smooth muscle tone increases airway responsiveness in healthy young adults. Am J Physiol Lung Cell Mol Physiol 2016; 312:L348-L357. [PMID: 27941076 DOI: 10.1152/ajplung.00400.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 11/22/2022] Open
Abstract
Force adaptation, a process whereby sustained spasmogenic activation (viz., tone) of airway smooth muscle (ASM) increases its contractile capacity, has been reported in isolated ASM tissues in vitro, as well as in mice in vivo. The objective of the present study was to assess the effect of tone on airway responsiveness in humans. Ten healthy volunteers underwent methacholine challenge on two occasions. One challenge consisted of six serial doses of saline followed by a single high dose of methacholine. The other consisted of six low doses of methacholine 5 min apart followed by a higher dose. The cumulative dose was identical for both challenges. After both methacholine challenges, subjects took a deep inspiration (DI) to total lung capacity as another way to probe ASM mechanics. Responses to methacholine and the DI were measured using a multifrequency forced oscillation technique. Compared with a single high dose, the challenge preceded by tone led to an elevated response measured by respiratory system resistance (Rrs) and reactance at 5 Hz. However, there was no difference in the increase in Rrs at 19 Hz, suggesting a predominant effect on smaller airways. Increased tone also reduced the efficacy of DI, measured by an attenuated maximal dilation during the DI and an increased renarrowing post-DI. We conclude that ASM tone increases small airway responsiveness to inhaled methacholine and reduces the effectiveness of DI in healthy humans. This suggests that force adaptation may contribute to airway hyperresponsiveness and the reduced bronchodilatory effect of DI in asthma.
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Affiliation(s)
- Morgan Gazzola
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Katherine Lortie
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Samuel Mailhot-Larouche
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - David G Chapman
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, Vermont
| | - Christian Couture
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Chun Y Seow
- University of British Columbia Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Peter D Paré
- University of British Columbia Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Gregory G King
- Woolcock Institute of Medical Research, Sydney, Australia.,University of Sydney, Sydney, Australia; and.,Cooperative Research Centre for Asthma, Sydney, Australia
| | - Louis-Philippe Boulet
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada;
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19
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Abstract
Asthma affects a significant proportion of elderly patients, but unfortunately, it is responsible for a high asthma-related morbidity and mortality in this population. This may be related not only to the development of a more severe asthma phenotype compared to younger patients, with more marked airway obstruction and a more neutrophilic type of airway inflammation, but also to the presence of many co-morbid conditions. Furthermore, in older patients, asthma is often under-diagnosed, undertreated and poorly managed. Unfortunately, elderly patients have usually been excluded of clinical trials on asthma and there is an urgent need to perform more research on the optimal management of asthma in this population.
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Affiliation(s)
- Louis-Philippe Boulet
- Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Québec City, Québec G1V 4G5 Canada
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20
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Chapman DG, Irvin CG. Mechanisms of airway hyper-responsiveness in asthma: the past, present and yet to come. Clin Exp Allergy 2015; 45:706-19. [PMID: 25651937 DOI: 10.1111/cea.12506] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Airway hyper-responsiveness (AHR) has long been considered a cardinal feature of asthma. The development of the measurement of AHR 40 years ago initiated many important contributions to our understanding of asthma and other airway diseases. However, our understanding of AHR in asthma remains complicated by the multitude of potential underlying mechanisms which in reality are likely to have different contributions amongst individual patients. Therefore, the present review will discuss the current state of understanding of the major mechanisms proposed to contribute to AHR and highlight the way in which AHR testing is beginning to highlight distinct abnormalities associated with clinically relevant patient populations. In doing so we aim to provide a foundation by which future research can begin to ascribe certain mechanisms to specific patterns of bronchoconstriction and subsequently match phenotypes of bronchoconstriction with clinical phenotypes. We believe that this approach is not only within our grasp but will lead to improved mechanistic understanding of asthma phenotypes and we hoped to better inform the development of phenotype-targeted therapy.
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Affiliation(s)
- D G Chapman
- Woolcock Institute of Medical Research, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Medicine, University of Vermont College of Medicine, Burlington, VT, USA
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21
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Sears MR. Is the Aging Airway Less Responsive to Treatment? Am J Respir Crit Care Med 2015; 192:529-30. [PMID: 26325150 DOI: 10.1164/rccm.201506-1165ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Malcolm R Sears
- 1 McMaster University St. Joseph's Healthcare Hamilton, Ontario, Canada
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22
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Lui JK, Parameswaran H, Albert MS, Lutchen KR. Linking Ventilation Heterogeneity Quantified via Hyperpolarized 3He MRI to Dynamic Lung Mechanics and Airway Hyperresponsiveness. PLoS One 2015; 10:e0142738. [PMID: 26569412 PMCID: PMC4646346 DOI: 10.1371/journal.pone.0142738] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 10/25/2015] [Indexed: 11/18/2022] Open
Abstract
Advancements in hyperpolarized helium-3 MRI (HP 3He-MRI) have introduced the ability to render and quantify ventilation patterns throughout the anatomic regions of the lung. The goal of this study was to establish how ventilation heterogeneity relates to the dynamic changes in mechanical lung function and airway hyperresponsiveness in asthmatic subjects. In four healthy and nine mild-to-moderate asthmatic subjects, we measured dynamic lung resistance and lung elastance from 0.1 to 8 Hz via a broadband ventilation waveform technique. We quantified ventilation heterogeneity using a recently developed coefficient of variation method from HP 3He-MRI imaging. Dynamic lung mechanics and imaging were performed at baseline, post-challenge, and after a series of five deep inspirations. AHR was measured via the concentration of agonist that elicits a 20% decrease in the subject's forced expiratory volume in one second compared to baseline (PC20) dose. The ventilation coefficient of variation was correlated to low-frequency lung resistance (R = 0.647, P < 0.0001), the difference between high and low frequency lung resistance (R = 0.668, P < 0.0001), and low-frequency lung elastance (R = 0.547, P = 0.0003). In asthmatic subjects with PC20 values <25 mg/mL, the coefficient of variation at baseline exhibited a strong negative trend (R = -0.798, P = 0.02) to PC20 dose. Our findings were consistent with the notion of peripheral rather than central involvement of ventilation heterogeneity. Also, the degree of AHR appears to be dependent on the degree to which baseline airway constriction creates baseline ventilation heterogeneity. HP 3He-MRI imaging may be a powerful predictor of the degree of AHR and in tracking the efficacy of therapy.
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Affiliation(s)
- Justin K. Lui
- Boston University, School of Medicine, Boston, MA, United States of America
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
| | | | - Mitchell S. Albert
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA, United States of America
- Department of Chemistry, Lakehead University, Thunder Bay, ON, Canada
- Thunder Bay Regional Research Institute, Thunder Bay, ON, Canada
| | - Kenneth R. Lutchen
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
- * E-mail:
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23
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Reisacher WR. Asthma and the otolaryngologist. Int Forum Allergy Rhinol 2015; 4 Suppl 2:S70-3. [PMID: 25182360 DOI: 10.1002/alr.21386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 11/06/2022]
Abstract
BACKGROUND Asthma is a chronic inflammatory disease of the lower airway that is commonly encountered by the otolaryngologist. This article provides information on how to recognize patients with asthma and discuss issues related to diagnosis, treatment, and continued management within the context of current guidelines. METHODS A literature review was conducted and relevant sources are referenced concerning the epidemiology of asthma, the pathophysiology of asthma, diagnostic strategies, treatment options, and continued management. RESULTS Asthma is a common condition worldwide and is often associated with other atopic diseases such as allergic rhinitis and eczema, though other genetic and environmental factors appear to be important as well. The lower airway and upper airways share similar histology, as well as patterns of inflammation in response to environmental triggers. The diagnosis of asthma involves a careful history and a complete physical exam, including auscultation of the lungs and pulmonary function testing. Pharmacotherapy represents the primary method of treating asthma, though current evidence supports a positive role for antigen-specific immunotherapy for both prevention and treatment. Guidelines are available that can assist the otolaryngologist in classifying the severity of asthma, determining the level of control and recommending modifications in the treatment plan. CONCLUSION As airway specialists, otolaryngologists are in a unique position to recognize and manage asthma in their patients, particularly those with allergic disease. Maintaining a high index of suspicion and understanding the key elements of diagnosis and treatment are extremely important in order to achieve this goal.
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Affiliation(s)
- William R Reisacher
- Department of Otolaryngology-Head and Neck Surgery, Weill Cornell Medical College, New York, NY
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24
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Farah CS, Keulers LAB, Hardaker KM, Peters MJ, Berend N, Postma DS, Salome CM, King GG. Association between peripheral airway function and neutrophilic inflammation in asthma. Respirology 2015; 20:975-81. [PMID: 25952106 DOI: 10.1111/resp.12550] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/04/2014] [Accepted: 02/23/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVE Small airway dysfunction is associated with asthma severity and control, but its association with airway inflammation is unknown. The aim was to determine the association between sputum inflammatory cells and the site of small airway dysfunction, measured by multiple breath nitrogen washout in convection-dependent (Scond) and more peripheral diffusion-dependent (Sacin) airways. METHODS Fifty-three (20-67 years) subjects with asthma on inhaled corticosteroid (ICS) treatment were characterized by spirometry, Scond, Sacin and induced sputum differential counts. %Predicted values for Scond and Sacin were calculated from published reference equations to adjust for the effects of age. Univariate correlations were assessed using the Spearman test. Multivariate linear regressions were performed to account for potential confounders, including age, gender, disease duration, body mass index and ICS dose. RESULTS Sacin (%predicted) correlated significantly with neutrophil% (rs = 0.33, P = 0.02), ICS dose (rs = -0.28, P = 0.04) and age (rs = 0.27, P = 0.05). In multivariate analysis, Sacin related only to neutrophil% (adjusted R(2) = 0.18, P = 0.001). Scond (%predicted) correlated significantly only with eosinophil% (rs = 0.39, P = 0.004). There was a trend for a negative relationship with ICS dose (rs = -0.26, P = 0.06). In multivariate analysis, Scond related to eosinophil% and ICS dose independently (adjusted R(2) = 0.12, P = 0.02). CONCLUSIONS Acinar and conductive airway dysfunction is associated with different inflammatory profiles in asthmatic airways, independently of the effects of age and disease duration. The association between acinar airway dysfunction and neutrophilic airway inflammation may have implications for asthma treatment.
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Affiliation(s)
- Claude S Farah
- Physiology and Imaging Group, The Woolcock Institute of Medical Research, Glebe, Australia.,Sydney Medical School, The University of Sydney, Concord, Australia.,Department of Respiratory Medicine, Concord Hospital, Concord, Australia
| | - Laurien A B Keulers
- University of Groningen, University Medical Center Groningen, Department of Pulmonology, GRIAC Research Institute, Groningen, The Netherlands
| | - Kate M Hardaker
- Physiology and Imaging Group, The Woolcock Institute of Medical Research, Glebe, Australia.,Sydney Medical School, The University of Sydney, Concord, Australia
| | - Matthew J Peters
- Sydney Medical School, The University of Sydney, Concord, Australia.,Department of Respiratory Medicine, Concord Hospital, Concord, Australia
| | - Norbert Berend
- Physiology and Imaging Group, The Woolcock Institute of Medical Research, Glebe, Australia.,Sydney Medical School, The University of Sydney, Concord, Australia.,Respiratory Research Group, The George Institute for Global Health, Sydney, NSW, Australia
| | - Dirkje S Postma
- University of Groningen, University Medical Center Groningen, Department of Pulmonology, GRIAC Research Institute, Groningen, The Netherlands
| | - Cheryl M Salome
- Physiology and Imaging Group, The Woolcock Institute of Medical Research, Glebe, Australia.,Sydney Medical School, The University of Sydney, Concord, Australia
| | - Gregory G King
- Physiology and Imaging Group, The Woolcock Institute of Medical Research, Glebe, Australia.,Sydney Medical School, The University of Sydney, Concord, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, New South Wales, Australia
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25
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Kaminsky DA, Daud A, Chapman D. Relationship between the baseline alveolar volume-to-total lung capacity ratio and airway responsiveness. Respirology 2014; 19:1046-51. [PMID: 24995907 PMCID: PMC4162905 DOI: 10.1111/resp.12347] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 02/27/2014] [Accepted: 05/22/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE Ventilation heterogeneity (VH) has been linked to airway responsiveness (AR) based on various measures of VH involving inert gas washout, forced oscillation and lung imaging. We explore whether VH at baseline, as measured by the simple ratio of single breath alveolar volume to plethysmographically determined total lung capacity (VA/TLC), would correlate with AR as measured by methacholine challenge testing. METHODS We analysed data from spirometry, lung volumes, diffusing capacity and methacholine challenge to derive the VA/TLC and the dose-response slope (DRS) of forced expiratory volume in 1 s (DRS-FEV1) during methacholine challenge from 136 patients. We separated out airway closure versus narrowing by examining the DRS for forced vital capacity (DRS-FVC) and the DRS for FEV1/FVC (DRS-FEV1/FVC), respectively. Similarly, we calculated the DRS for sGaw (DRS-sGaw) as another measure of airway narrowing. We performed statistical analysis using Spearman rank correlation and multifactor linear regression using a backward stepwise modelling procedure. RESULTS We found that the DRS-FEV1 correlated with baseline VA/TLC (rho = -0.26, P < 0.01), and VA/TLC and FEV1 were independently associated with DRS-FEV1 (R(2) = 0.14, P = 0.01). In addition, VA/TLC was associated with both airway narrowing and closure in response to methacholine. CONCLUSIONS These results confirm that baseline VA/TLC is associated with AR, and reflects both airway closure and airway narrowing following methacholine challenge.
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Affiliation(s)
- David A. Kaminsky
- Vermont Lung Center, Pulmonary Disease and Critical Care Medicine, University of Vermont College of Medicine Given D-213, 89 Beaumont Avenue, Burlington, VT, USA
| | - Anees Daud
- University of Vermont College of Medicine, Burlington, VT, USA
| | - David Chapman
- Vermont Lung Center, Pulmonary Disease and Critical Care Medicine, University of Vermont College of Medicine Given D-213, 89 Beaumont Avenue, Burlington, VT, USA
- Woolcock Institute of Medical Research, University of Sydney, NSW, Australia
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26
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Abstract
Non-uniform distribution of inspired gas within the lung, termed ventilation heterogeneity, is present in patients with even mild asthma. Current evidence strongly supports ventilation heterogeneity as a fundamental derangement of lung function in asthma that contributes per se to hypoxemia and airway hyper-responsiveness. An extreme example of ventilation heterogeneity is the identification by hyperpolarized gas MRI of lung regions with no ventilation, termed filling defects. Lung filling defects in patients with asthma can persist over time, increase in size with methacholine-induced bronchospasm and more likely are caused by obstruction of the peripheral and not the proximal airways. Ventilation heterogeneity can be quantified in the conducting and acinar lung zones with the multiple gas washout method, and in the acinar zone does not fully resolve following bronchodilator treatment in patients with asthma. In prospective studies, the degree of ventilation heterogeneity at baseline predicts airway hyper-responsiveness and response to corticosteroid dose titration. An important unanswered question is the relationship of airways inflammation to ventilation heterogeneity. In consideration of the importance of ventilation heterogeneity in its pathobiology, asthma is more a focal disorder with regional pathology akin to regional ileitis and not the generalized disorder of the airways as it has been viewed in the past.
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Affiliation(s)
- W Gerald Teague
- Division of Respiratory Medicine, Allergy, and Immunology, Department of Pediatrics and
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27
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Al-Alawi M, Hassan T, Chotirmall SH. Advances in the diagnosis and management of asthma in older adults. Am J Med 2014; 127:370-8. [PMID: 24380710 DOI: 10.1016/j.amjmed.2013.12.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/25/2013] [Accepted: 12/02/2013] [Indexed: 11/25/2022]
Abstract
Global estimates on aging predict an increased burden of asthma in the older population. Consequently, its recognition, diagnosis, and management in clinical practice require optimization. This review aims to provide an update for clinicians, highlighting advances in the understanding of the aging process and immunosenescence together with their applicability to asthma from a diagnostic and therapeutic perspective. Aging impacts airway responses and immune function, and influences efficacy of emerging phenotype-specific therapies when applied to the elderly patient. Differentiating eosinophilic and neutrophilic disease accounts for atopic illness and distinguishes long-standing from late-onset asthma. Therapeutic challenges in drug delivery, treatment adherence, and side-effect profiles persist in the older patient, while novel recording devices developed to aid detection of an adequate inhalation evaluate treatment effectiveness and compliance more accurately than previously attainable. Anticytokine therapies improve control of brittle asthma, while bronchial thermoplasty is an option in refractory cases. Multidimensional intervention strategies prove best in the management of asthma in the older adult, which remains a condition that is not rare but rarely diagnosed in this patient population.
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Affiliation(s)
- Mazen Al-Alawi
- Department of Medicine, Our Lady of Lourdes Hospital, Navan, Republic of Ireland
| | - Tidi Hassan
- Department of Respiratory Medicine, Mater Misericordiae Hospital, Eccles Street, Dublin 7, Republic of Ireland
| | - Sanjay H Chotirmall
- Department of Medicine, St James's Hospital, James's Street, Dublin 8, Republic of Ireland.
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28
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Robitaille C, Boulet LP. [Asthma in the elderly]. Rev Mal Respir 2014; 31:478-87. [PMID: 25012034 DOI: 10.1016/j.rmr.2014.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 01/16/2014] [Indexed: 01/09/2023]
Abstract
Asthma is a common condition in the elderly although often confounded with chronic obstructive pulmonary disease (COPD) in this population. Asthma in the elderly seems to represent a specific phenotype characterized by more severe, but often less perceived, airway obstruction, a neutrophilic or mixed-type of airway inflammation and frequent comorbidities. Patients aged 65 years and over have an increased asthma-related morbidity and mortality compared to younger patients, probably due to difficulties in regard to diagnosis, assessment of the disease severity and treatment. Research is urgently needed to determine the optimal treatment of the aged patient. In this document we will review the state of knowledge on this topic and discuss the challenges of multidisciplinary asthma management in the elderly.
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Affiliation(s)
- C Robitaille
- Institut universitaire de cardiologie et de pneumologie de Québec, université Laval, 2725, chemin Sainte-Foy, G1V 4G5 Québec, QC, Canada
| | - L-P Boulet
- Institut universitaire de cardiologie et de pneumologie de Québec, université Laval, 2725, chemin Sainte-Foy, G1V 4G5 Québec, QC, Canada.
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29
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Abstract
Asthma and COPD are both heterogeneous lung diseases including many different phenotypes. The classical asthma and COPD phenotypes are easy to discern because they reflect extremes of a phenotypical spectrum. Thus asthma in childhood and COPD in smokers have their own phenotypic expression with underlying pathophysiological mechanisms that differ importantly. In older adults, asthma and COPD are more difficult to differentiate and there exists a bronchodilator response in most but not all patients with asthma and persistent airway obstruction in most but not all patients with COPD where even up to 50% have been reported to have some bronchodilator response as assessed with FEV1. Airway obstruction is generated in the large and small airways both in asthma and COPD, and this small airway obstruction is located more proximally in asthma, yet is found more distally in severe and older individuals with asthma, comparable to COPD. Though the underlying inflammation and remodelling processes in asthma and COPD are different in their extreme phenotypes, there are overlap phenotypes with eosinophilic inflammation even in stable COPD and neutrophilic inflammation in longstanding and severe asthma.
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Columbo M, Wong B, Panettieri RA, Rohr AS. The effect of multiple allergen immunotherapy on exhaled nitric oxide in adults with allergic rhinitis. Allergy Asthma Clin Immunol 2013; 9:31. [PMID: 23958488 PMCID: PMC3751795 DOI: 10.1186/1710-1492-9-31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/30/2013] [Indexed: 11/29/2022] Open
Abstract
Background There is a lack of objective measures of the clinical efficacy of allergen immunotherapy which relies on patients’ perception about the effect of this treatment. We studied whether the fraction of exhaled nitric oxide is affected by multiple allergen immunotherapy in polysensitized adult subjects with allergic rhinitis. We also looked for associations between exhaled nitric oxide and subjects’ demographics, symptom scores, and pulmonary function tests. Methods Twenty adult, polysensitized subjects with seasonal and perennial allergic rhinitis who chose to undergo allergen immunotherapy were enrolled. They were evaluated at baseline, and 4, 8, 12, 24, and 52 weeks later. Exhaled nitric oxide was reported as the mean of triplicate determinations. Findings Our results indicate that multiple allergen immunotherapy did not affect exhaled nitric oxide levels and such levels did not correlate with subjects’ demographics and pulmonary function tests. However, exhaled nitric oxide was associated with rhinoconjuctivitis and asthma symptom scores at the end of the study. Conclusions In polysensitized adult subjects with allergic rhinitis, exhaled nitric oxide levels are unaffected by multiple allergen immunotherapy.
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Affiliation(s)
- Michele Columbo
- Asthma, Allergy and Immunology Specialists, 875 County Line Road-Suite 107, Bryn Mawr, PA 19010, USA
| | - Bruce Wong
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Reynold A Panettieri
- Pulmonary, Allergy and Critical Care Division, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Albert S Rohr
- Asthma, Allergy and Immunology Specialists, 875 County Line Road-Suite 107, Bryn Mawr, PA 19010, USA
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31
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Hardaker KM, Downie SR, Kermode JA, Berend N, King GG, Salome CM. Ventilation heterogeneity is associated with airway responsiveness in asthma but not COPD. Respir Physiol Neurobiol 2013; 189:106-11. [PMID: 23876741 DOI: 10.1016/j.resp.2013.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/19/2013] [Accepted: 07/04/2013] [Indexed: 11/18/2022]
Abstract
Airway hyperresponsiveness (AHR) occurs in both asthma and COPD. In older people with asthma, AHR is associated with increased acinar ventilation heterogeneity, but it is unknown if this association exists in COPD. Thirty one COPD and 19 age-matched asthmatic subjects had measures of spirometry, lung volumes, exhaled nitric oxide, ventilation heterogeneity, and methacholine challenge. Indices of acinar (Sacin) and conducting (Scond) airway ventilation heterogeneity were calculated from the multiple breath nitrogen washout. Predictors of AHR were then determined. In COPD, AHR was predicted by lower Sacin and lower FVC (model r(2)=0.35, p=0.001). In asthma, AHR was predicted by higher Sacin and higher residual volume (model r(2)=0.62, p<0.001). These findings suggest that airway responsiveness in COPD and asthma is determined by underlying disease-specific processes, rather than a common pattern of physiological abnormality.
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Affiliation(s)
- Kate M Hardaker
- Woolcock Institute of Medical Research, PO Box M77, Missenden Rd, Glebe NSW 2050, Australia; University of Sydney, Darlington, Australia; Cooperative Research Centre for Asthma and Airways, Glebe, Australia.
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32
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Multiple breath nitrogen washout profiles in asthmatic patients: what do they mean clinically? J Allergy Clin Immunol 2013; 131:1329-30. [PMID: 23541321 DOI: 10.1016/j.jaci.2013.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 02/15/2013] [Indexed: 11/23/2022]
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33
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Columbo M, Wong B, Panettieri RA, Rohr AS. Asthma in the elderly: the role of exhaled nitric oxide measurements. Respir Med 2013; 107:785-7. [PMID: 23481173 DOI: 10.1016/j.rmed.2013.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/16/2013] [Accepted: 01/27/2013] [Indexed: 10/27/2022]
Abstract
Asthma in the elderly is poorly understood because only a small minority of asthma studies have investigated this patients group. Fractional exhaled nitric oxide (FENO) has been extensively studied in children and adults with asthma, but little is known about FENO in elderly asthmatics. We studied the role of serial measurements of FENO in elderly subjects with asthma. Thirty stable asthmatics 65 years old and older were followed for one year with evaluations at baseline and every three months. We looked for associations between FENO and subjects' demographics, comorbidities, asthma treatment, spirometric values and asthma control test (ACT) scores. FENO was not elevated in our study subjects throughout the study period (mean < 30 ppb). FENO significantly increased and FEV1% decreased between first and last study visit, while ACT scores and steroid dose remained unchanged. No significant correlation was found between FENO and FEV1/FVC, other spirometric values, inhaled steroid dose or ACT scores at any time point. No associations of FENO were found with age, sex, body mass index (BMI), atopic status, disease duration, presence of rhinitis or gastroesophageal reflux disease (GERD), or other medications used. Moderate asthma exacerbations did not consistently cause an increase of FENO. In stable elderly asthmatic patients, FENO was not elevated and did not correlate with subjects' demographics, comorbidities, treatment, symptoms or spirometric values. Routine measurements of FENO may not be clinically valuable in elderly asthmatics.
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Affiliation(s)
- Michele Columbo
- Asthma, Allergy and Immunology Specialists, 875 County Line Road, Bryn Mawr, PA 19010, USA.
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34
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He JQ, Chan-Yeung M, Carlsten C. Airway hyperresponsiveness and quality of life in Western red cedar asthmatics removed from exposure. PLoS One 2012; 7:e50774. [PMID: 23226539 PMCID: PMC3514170 DOI: 10.1371/journal.pone.0050774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Accepted: 10/24/2012] [Indexed: 02/05/2023] Open
Abstract
Objectives Most western red cedar asthmatics (WRCA) continue to have symptoms even after removal from exposure. Consequently, health-related quality of life (HRQL) is often impaired. The objective of this study was to evaluate the relationship between two measures of AHR and HRQL scores in those with WRCA. Methods HRQL was determined by the short form 36 (SF-36) in 46 male, non-smoking individuals with WRCA removed from exposure to western red cedar, on average, 15 years earlier. The relationships between the SF-36 total score and its eight domains with 2 indices from methacholine-stimulated airway hyperresponsiveness (the provocative concentration of methacholine causing a 20% fall in FEV1 [PC20] and bronchial reactivity index [BRI]) were analyzed by the Pearson correlation and multiple linear regression. Results PC20 was significantly correlated with the SF-36 total score and its two domains of bodily pain and general health (r = 0.34, 0.40, 0.40, p = 0.023, 0.006, 0.006, respectively). BRI was significantly correlated with bodily pain and general health (r = −0.35, −0.42, p = 0.017, 0.004, respectively); correlations remain significant after adjusting for age, ethnicity, years since diagnosis, years since last exposure and use of inhaled corticosteroid. BRI and other measures of airway responsiveness were not associated with inhaled corticosteroids use. Conclusions In Western red cedar asthmatics removed from exposure, measures of airway responsiveness are associated with HRQL.
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Affiliation(s)
- Jian-Qing He
- Department of Respiratory Medicine. West China Hospital, West China Medical School, Sichuan University, Chengdu, China
- Respiratory Division, Department of Medicine, University of British Columbia, and Centre for Lung Health, Vancouver General Hospital, Vancouver, British Columbia, Canada
- * E-mail: (CC); (JQH)
| | - Moira Chan-Yeung
- Respiratory Division, Department of Medicine, University of British Columbia, and Centre for Lung Health, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Chris Carlsten
- Respiratory Division, Department of Medicine, University of British Columbia, and Centre for Lung Health, Vancouver General Hospital, Vancouver, British Columbia, Canada
- * E-mail: (CC); (JQH)
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Abstract
Noninvasive physiological measurements are reviewed that have been reported in the literature with the specific aim being to study the small airways in lung disease. This has mostly involved at-the-mouth noninvasive measurement of flow, pressure or inert gas concentration, with the intent of deriving one or more indices that are representative of small airway structure and function. While these measurements have remained relatively low-tech, the effort and sophistication increasingly reside with the interpretation of such indices. When aspiring to derive information at the mouth about structural and mechanical processes occurring several airway generations away in a complex cyclically changing cul-de-sac structure, conceptual or semi-quantitative lung models can be valuable. Two assumptions that are central to small airway structure-function measurement are that of an average airway change at a given peripheral lung generation and of a parallel heterogeneity in airway changes. While these are complementary pieces of information, they can affect certain small airways tests in confounding ways. We critically analyzed the various small airway tests under review, while contending that negative outcomes of these tests are probably a true reflection of the fact that no change occurred in the small airways. Utmost care has been taken to not favor one technique over another, given that most current small airways tests still have room for improvement in terms of rendering their content more specific to the small airways. One way to achieve this could consist of the coupling of signals collected at the mouth to spatial information gathered from imaging in the same patient.
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Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, University Hospital UZ Brussel, Brussels, Belgium.
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Chapman DG, Berend N, Horlyck KR, King GG, Salome CM. Does increased baseline ventilation heterogeneity following chest wall strapping predispose to airway hyperresponsiveness? J Appl Physiol (1985) 2012; 113:25-30. [PMID: 22556397 DOI: 10.1152/japplphysiol.01582.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Baseline ventilation heterogeneity is associated with airway hyperresponsiveness (AHR) in asthma; however, it is unknown whether increased baseline ventilation heterogeneity leads to AHR or both are independent effects of similar disease pathophysiology. Reducing functional residual capacity (FRC) in healthy subjects increases baseline ventilation heterogeneity and airway responsiveness, but the relationship between the two is unclear. The aim was to determine whether an increase in baseline ventilation heterogeneity due to a reduction in FRC correlated with the increase in response to methacholine. In 13 healthy male subjects, ventilation heterogeneity was measured by multiple-breath N(2) washout before a cumulative high-dose (0.79-200 μmol) methacholine challenge. On a separate day, the protocol was performed with chest wall strapping (CWS) to reduce FRC. Indexes of ventilation heterogeneity in the convection-dependent (Scond) and diffusion-convection-dependent (Sacin) airways were calculated from the multiple-breath N(2) washout. CWS decreased FRC by 15.6 ± 2.7% (P < 0.0001). CWS increased the percent fall in forced expiratory volume in 1 s during bronchial challenge (P = 0.006), and the magnitude of this effect was independently determined by the effect of CWS on Sacin and FRC (r(adj)(2) = 0.55, P = 0.02). This suggests that changes in baseline ventilation heterogeneity in healthy subjects are sufficient to increase airway responsiveness, independent of the presence of disease pathology.
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Affiliation(s)
- David G Chapman
- Woolcock Institute of Medical Research, Sydney, New South Wales, Australia.
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Schleich FN, Asandei R, Manise M, Sele J, Seidel L, Louis R. Is FENO50 useful diagnostic tool in suspected asthma? Int J Clin Pract 2012; 66:158-65. [PMID: 22257040 DOI: 10.1111/j.1742-1241.2011.02840.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Asthma diagnosis is based on the presence of symptoms and the demonstration of airflow variability. Airway inflammation measured by fractional exhaled nitric oxide, measured at a flow rate of 50 ml/s (FE(NO50)) remains a controversial diagnostic tool. AIM To assess the ability of FE(NO50) to identify bronchial hyperresponsiveness (BHR) to methacholine (provocative concentration of methacholine causing a 20% fall in FEV(1); PC20M ≤ 16 mg/ml) and to establish whether or not symptoms relate to FE(NO50) and PC20M in patients with no demonstrated reversibility to β(2) -agonist. METHODS We conducted a prospective study on 174 steroid naive patients with respiratory symptoms, forced expiratory volume in 1 s (FEV(1) ) ≥ 70% predicted and no demonstrated reversibility to β(2) -agonist. Patients answered to a standardised symptom questionnaire and underwent FE(NO50) and methacholine challenge. Receiver-operating characteristic (ROC) curve and logistic regression analysis assessed the relationship between PC20M and FE(NO50) , taking into account covariates (smoking, atopy, age, gender and FEV(1)). RESULTS A total of 82 patients had a PC20M ≤ 16 mg/ml and had significantly higher FE(NO50) (19 ppb vs. 15 ppb; p < 0.05). By constructing ROC curve, we found that FE(NO50) cut-off value of 34 ppb was able to identify not only BHR with high specificity (95%) and positive predictive value (88%) but low sensitivity (35%) and negative predictive value (62%). When combining all variables into the logistic model, FE(NO50) (p = 0.0011) and FEV(1) (p < 0.0001) were independent predictors of BHR whereas age, gender, smoking and atopy had no influence. The presence of diurnal and nocturnal wheezing was associated with raised FE(NO50) (p < 0.001 and p < 0.05, respectively). CONCLUSION The value of FE(NO50) > 34 ppb has high predictive value of PC20M < 16 in patients with suspected asthma in whom bronchodilating test failed to demonstrate reversibility or was not indicated. However, FE(NO50) ≤ 34 ppb does not rule out BHR and should prompt the clinician to ask for a methacholine challenge.
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Affiliation(s)
- F N Schleich
- Department of Pulmonary Medicine, CHU Sart-Tilman, Liege, I3 GIGA research Group, Belgium.
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Abstract
Pulmonary function testing is part of routine clinical practice in respiratory medicine. It is based around spirometry, which will remain the central measurement of lung function given its prognostic significance and its integral role in defining severity of airways disease. However, there is an increasing body of evidence from studies using new methods of lung function measurement which are providing new insights into pathophysiology of disease. This body of data is forming a basis for their future clinical role, once the economics of producing the relevant devices becomes attractive. The forced oscillation technique and multiple breath nitrogen washout are currently the most commonly used of the newer lung function techniques, which are refinements of long-established techniques. Optical coherence tomography, optical reflection, electrical impedance and vibration response imaging have arisen by development of novel devices. The recent use of these techniques is reviewed.
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Affiliation(s)
- Gregory G King
- Woolcock Institute of Medical Research, The Northern Clinical School, Sydney Medical School, University of Sydney, New South Wales, Australia.
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A 'Good' muscle in a 'Bad' environment: the importance of airway smooth muscle force adaptation to airway hyperresponsiveness. Respir Physiol Neurobiol 2011; 179:269-75. [PMID: 21939788 DOI: 10.1016/j.resp.2011.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 08/17/2011] [Accepted: 09/06/2011] [Indexed: 12/31/2022]
Abstract
Asthma is characterized by airway inflammation, with a consequent increase in spasmogens, and exaggerated airway narrowing in response to stimuli, termed airway hyperresponsiveness (AHR). The nature of any relationship between inflammation and AHR is less clear. Recent ex vivo data has suggested a novel mechanism by which inflammation may lead to AHR, in which increased basal ASM-tone, due to the presence of spasmogens in the airways, may "strengthen" the ASM and ultimately lead to exaggerated airway narrowing. This phenomenon was termed "force adaptation" [Bossé, Y., Chin, L.Y., Paré, P.D., Seow, C.Y., 2009. Adaptation of airway smooth muscle to basal tone: relevance to airway hyperresponsiveness. Am. J. Respir. Cell Mol. Biol. 40, 13-18]. However, it is unknown whether the magnitude of the effect of force adaptation ex vivo could contribute to exaggerated airway narrowing in vivo. Our aim was to utilize a computational model of ASM shortening in order to quantify the potential effect of force adaptation on airway narrowing when all other mechanical factors were kept constant. The shortening in the model is dictated by a balance between physiological loads and ASM force-generating capacity at different lengths. The results suggest that the magnitude of the effect of force adaptation on ASM shortening would lead to substantially more airway narrowing during bronchial challenge at any given airway generation. We speculate that the increased basal ASM-tone in asthma, due to the presence of inflammation-derived spasmogens, produces an increase in the force-generating capacity of ASM, predisposing to AHR during subsequent challenge.
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