1
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Yasuda Y, Wang L, Chitano P, Seow CY. Critical roles of airway smooth muscle in mediating deep-inspiration-induced bronchodilation: a big stretch? Respir Res 2023; 24:250. [PMID: 37853472 PMCID: PMC10585885 DOI: 10.1186/s12931-023-02538-8] [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: 08/15/2023] [Accepted: 09/14/2023] [Indexed: 10/20/2023] Open
Abstract
BACKGROUND Deep inspiration (DI) has been shown to induce bronchodilation and bronchoprotection in bronchochallenged healthy subjects, but not in asthmatics. Strain-induced relaxation of airway smooth muscle (ASM) is considered one of the factors responsible for these effects. Other factors include the release or redistribution of pulmonary surfactant, alteration in mucus plugs, and changes in airway heterogeneity. MAIN BODY The present review is focused on the DI effect on ASM function, based on recent findings from ex vivo sheep lung experiments showing a large change in airway diameter during a DI. The amount of stretch on the airways, when applied to isolated airway rings in vitro, caused a substantial decrease in ASM contractility that takes many minutes to recover. When challenged with a bronchoconstrictor, the increase in pulmonary resistance in the ex vivo ovine lungs is mostly due to the increase in airway resistance. CONCLUSIONS Although non-ASM related factors cannot be excluded, the large strain on the airways associated with a DI substantially reduces ASM contractility and thus can account for most of the bronchodilatory and bronchoprotective effects of DI.
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Affiliation(s)
- Yuto Yasuda
- Centre for Heart Lung Innovation, St. Paul's Hospital, Providence Health Care, University of British Columbia, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada.
| | - Lu Wang
- Centre for Heart Lung Innovation, St. Paul's Hospital, Providence Health Care, University of British Columbia, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada
| | - Pasquale Chitano
- Centre for Heart Lung Innovation, St. Paul's Hospital, Providence Health Care, University of British Columbia, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada
| | - Chun Y Seow
- Centre for Heart Lung Innovation, St. Paul's Hospital, Providence Health Care, University of British Columbia, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
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2
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Boucher M, Dufour-Mailhot A, Tremblay-Pitre S, Khadangi F, Rojas-Ruiz A, Henry C, Bossé Y. In mice of both sexes, repeated contractions of smooth muscle in vivo greatly enhance the response of peripheral airways to methacholine. Respir Physiol Neurobiol 2022; 304:103938. [PMID: 35716869 DOI: 10.1016/j.resp.2022.103938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/10/2022] [Accepted: 06/12/2022] [Indexed: 10/18/2022]
Abstract
BALB/c mice from both sexes underwent one of two nebulized methacholine challenges that were preceded by a period of 20 min either with or without tone induced by repeated contractions of the airway smooth muscle. Impedance was monitored throughout and the constant phase model was used to dissociate the impact of tone on conducting airways (RN - Newtonian resistance) versus the lung periphery (G and H - tissue resistance and elastance). The effect of tone on smooth muscle contractility was also tested on excised tracheas. While tone markedly potentiated the methacholine-induced gains in H and G in both sexes, the gain in RN was only potentiated in males. The contractility of female and male tracheas was also potentiated by tone. Inversely, the methacholine-induced gain in hysteresivity (G/H) was mitigated by tone in both sexes. Therefore, the tone-induced muscle hypercontractility impacts predominantly the lung periphery in vivo, but also promotes further airway narrowing in males while protecting against narrowing heterogeneity in both sexes.
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Affiliation(s)
- Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Alexis Dufour-Mailhot
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Sophie Tremblay-Pitre
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Andrés Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada.
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3
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Dong SJ, Wang L, Chitano P, Coxson HO, Paré PD, Seow CY. Airway diameter at different transpulmonary pressures in ex vivo sheep lungs: Implications for deep-inspiration-induced bronchodilation and bronchoprotection. Am J Physiol Lung Cell Mol Physiol 2021; 321:L663-L674. [PMID: 34287071 DOI: 10.1152/ajplung.00208.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Deep inspiration (DI)-induced bronchodilation is the first line of defense against bronchoconstriction in healthy subjects. A hallmark of asthma is the lack of this beneficial effect of DI. The mechanism underlying the bronchodilatory effect of DI is not clear. Understanding the mechanism will help us unravel the mystery of asthma pathophysiology. It has been postulated that straining airway smooth muscle (ASM) during a DI could lead to bronchodilation and bronchoprotection. The hypothesis is currently under debate, and a central question is whether ASM is sufficiently stretched during a DI for its contractility to be compromised. Besides bronchoconstriction, another contributor to lung resistance is airway heterogeneity. The present study examines changes in airway diameter and heterogeneity at different lung volumes. Freshly explanted sheep lungs were used in plethysmographic measurements of lung resistance and elastance at different lung volumes while the airway dimensions were measured by computed tomography (CT). The change in airway diameter informed by CT measurements was applied to isolated airway ring preparations to determine the strain-induced loss of ASM contractility. We found that changing the transpulmonary pressure from 5 to 30 cmH2O led to a 51%-increase in lung volume, accompanied by a 46%-increase in the airway diameter with no change in airway heterogeneity. When comparable airway strains measured in the whole lung were applied to isolated airway rings in either relaxed or contracted state, a significant loss of ASM contractility was observed, suggesting that DI-induced bronchodilation and bronchoprotection can result from strain-induced loss of ASM contractility.
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Affiliation(s)
- Shou-Jin Dong
- The UBC Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Respiratory Department, Chengdu First People's Hospital, Chengdu, China
| | - Lu Wang
- The UBC Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada
| | - Pasquale Chitano
- The UBC Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada
| | - Harvey O Coxson
- The UBC Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada
| | - Peter D Paré
- The UBC Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Chun Y Seow
- The UBC Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
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4
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Phung TKN, Sinclair SE, Makena P, Molthen RC, Waters CM. Dynamic airway constriction in rats: heterogeneity and response to deep inspiration. Am J Physiol Lung Cell Mol Physiol 2019; 317:L39-L48. [PMID: 31017015 DOI: 10.1152/ajplung.00050.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Airway narrowing due to hyperresponsiveness severely limits gas exchange in patients with asthma. Imaging studies in humans and animals have shown that bronchoconstriction causes patchy patterns of ventilation defects throughout the lungs, and several computational models have predicted that these regions are due to constriction of smaller airways. However, these imaging approaches are often limited in their ability to capture dynamic changes in small airways, and the patterns of constriction are heterogeneous. To directly investigate regional variations in airway narrowing and the response to deep inspirations (DIs), we utilized tantalum dust and microfocal X-ray imaging of rat lungs to obtain dynamic images of airways in an intact animal model. Airway resistance was simultaneously measured using the flexiVent system. Custom-developed software was used to track changes in airway diameters up to generation 19 (~0.3-3 mm). Changes in diameter during bronchoconstriction were then measured in response to methacholine (MCh) challenge. In contrast with the model predictions, we observed significantly greater percent constriction in larger airways in response to MCh challenge. Although there was a dose-dependent increase in total respiratory resistance with MCh, the percent change in airway diameters was similar for increasing doses. A single DI following MCh caused a significant reduction in resistance but did not cause a significant increase in airway diameters. Multiple DIs did, however, cause significant increases in airway diameters. These measurements allowed us to directly quantify dynamic changes in airways during bronchoconstriction and demonstrated greater constriction in larger airways.
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Affiliation(s)
- Thien-Khoi N Phung
- Department of Physiology, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Scott E Sinclair
- Department of Physiology, University of Tennessee Health Science Center , Memphis, Tennessee.,Department of Medicine, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Patrudu Makena
- Department of Medicine, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Robert C Molthen
- Department of Medicine, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Christopher M Waters
- Department of Physiology, University of Tennessee Health Science Center , Memphis, Tennessee.,Department of Medicine, University of Tennessee Health Science Center , Memphis, Tennessee.,Department of Physiology and Saha Cardiovascular Research Center, University of Kentucky , Lexington, Kentucky
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5
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Osorio-Valencia JS, Wongviriyawong C, Winkler T, Kelly VJ, Harris RS, Venegas JG. Elevation in lung volume and preventing catastrophic airway closure in asthmatics during bronchoconstriction. PLoS One 2018; 13:e0208337. [PMID: 30566496 PMCID: PMC6300269 DOI: 10.1371/journal.pone.0208337] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/15/2018] [Indexed: 01/17/2023] Open
Abstract
Background Asthma exacerbations cause lung hyperinflation, elevation in load to inspiratory muscles, and decreased breathing capacity that, in severe cases, may lead to inspiratory muscle fatigue and respiratory failure. Hyperinflation has been attributed to a passive mechanical origin; a respiratory system time-constant too long for full exhalation. However, because the increase in volume is also concurrent with activation of inspiratory muscles during exhalation it is unclear whether hyperinflation in broncho-constriction is a passive phenomenon or is actively controlled to avoid airway closure. Methods Using CT scanning, we measured the distensibility of individual segmental airways relative to that of their surrounding parenchyma in seven subjects with asthma and nine healthy controls. With this data we tested whether the elevation of lung volume measured after methacholine (MCh) provocation was associated with airway narrowing, or to the volume required to preventing airway closure. We also tested whether the reduction in FVC post-MCh could be attributed to gas trapped behind closed segmental airways. Findings The changes in lung volume by MCh in subjects with and without asthma were inversely associated with their reduction in average airway lumen. This finding would be inconsistent with hyperinflation by passive elevation of airway resistance. In contrast, the change in volume of each subject was associated with the lung volume estimated to cause the closure of the least stable segmental airway of his/her lungs. In addition, the measured drop in FVC post MCh was associated with the estimated volume of gas trapped behind closed segmental airways at RV. Conclusions Our data supports the concept that hyperinflation caused by MCh-induced bronchoconstriction is the result of an actively controlled process where parenchymal distending forces on airways are increased to counteract their closure. To our knowledge, this is the first imaging-based study that associates inter-subject differences in whole lung behavior with the interdependence between individual airways and their surrounding parenchyma.
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Affiliation(s)
- Juan S. Osorio-Valencia
- Department of Computer Science, Graduate Program in Biomedical Computing, Technical University of Munich, Munich, Germany
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (JSO); (JGV)
| | - Chanikarn Wongviriyawong
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Tilo Winkler
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Vanessa J. Kelly
- Department of Medicine, Pulmonary and Critical Care Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Robert S. Harris
- Department of Medicine, Pulmonary and Critical Care Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jose G. Venegas
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (JSO); (JGV)
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6
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Taher H, Bauer C, Abston E, Kaczka DW, Bhatt SP, Zabner J, Brower RG, Beichel RR, Eberlein M. Chest wall strapping increases expiratory airflow and detectable airway segments in computer tomographic scans of normal and obstructed lungs. J Appl Physiol (1985) 2018; 124:1186-1193. [PMID: 29357485 PMCID: PMC6008079 DOI: 10.1152/japplphysiol.00184.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 12/22/2017] [Accepted: 12/28/2017] [Indexed: 11/22/2022] Open
Abstract
Chest wall strapping (CWS) induces breathing at low lung volumes but also increases parenchymal elastic recoil. In this study, we tested the hypothesis that CWS dilates airways via airway-parenchymal interdependence. In 11 subjects (6 healthy and 5 with mild to moderate COPD), pulmonary function tests and lung volumes were obtained in control (baseline) and the CWS state. Control and CWS-CT scans were obtained at 50% of control (baseline) total lung-capacity (TLC). CT lung volumes were analyzed by CT volumetry. If control and CWS-CT volumetry did not differ by more than 25%, airway dimensions were analyzed via automated airway segmentation. CWS-TLC was reduced on average to 71% of control-TLC in normal subjects and 79% of control-TLC in subjects with COPD. CWS increased expiratory airflow at 50% of control-TLC by 41% (3.50 ± 1.6 vs. 4.93 ± 1.9 l/s, P = 0.04) in normals and 316% in COPD(0.25 ± 0.05 vs 0.79 ± 0.39 l/s, P = 0.04). In 10 subjects (5 normals and 5 COPD), control and CWS-CT scans at 50% control-TLC did not differ more than 25% on CT volumetry and were included in the airway structure analysis. CWS increased the mean number of detectable airways with a diameter of ≤2 mm by 32.5% (65 ± 10 vs. 86 ± 124, P = 0.01) in normal subjects and by 79% (59 ± 19 vs. 104 ± 16, P = 0.01) in subjects with COPD. There was no difference in the number of detectable airways with diameters 2-4 mm and >4 mm in normal or in COPD subjects. In conclusion, CWS enhances the detection of small airways via automated CT airway segmentation and increases expiratory airflow in normal subjects as well as in subjects with mild to moderate COPD. NEW & NOTEWORTHY In normal and COPD subjects, chest wall strapping(CWS) increased the number of detectable small airways using automated CT airway segmentation. The concept of dysanapsis expresses the physiological variation in the geometry of the tracheobronchial tree and lung parenchyma based on development. We propose a dynamic concept to dysanapsis in which CWS leads to breathing at lower lung volumes with a corresponding increase in the size of small airways, a potentially novel, nonpharmacological treatment for COPD.
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Affiliation(s)
- Hisham Taher
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
| | - Christian Bauer
- Department of Electrical and Computer Engineering, University of Iowa , Iowa City, Iowa
- Iowa Institute for Biomedical Imaging, University of Iowa , Iowa City, Iowa
| | - Eric Abston
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
| | - David W Kaczka
- Department of Anesthesiology, University of Iowa , Iowa City, Iowa
- Department of Biomedical Engineering, University of Iowa , Iowa City, Iowa
- Department of Radiology, University of Iowa , Iowa City, Iowa
| | - Surya P Bhatt
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama , Birmingham, Alabama
| | - Joseph Zabner
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
| | - Roy G Brower
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University - Baltimore, Maryland
| | - Reinhard R Beichel
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
- Department of Electrical and Computer Engineering, University of Iowa , Iowa City, Iowa
- Iowa Institute for Biomedical Imaging, University of Iowa , Iowa City, Iowa
| | - Michael Eberlein
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
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7
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Boser SR, Mauad T, de Araújo-Paulino BB, Mitchell I, Shrestha G, Chiu A, Butt J, Kelly MM, Caldini E, James A, Green FHY. Myofibroblasts are increased in the lung parenchyma in asthma. PLoS One 2017; 12:e0182378. [PMID: 28787016 PMCID: PMC5546673 DOI: 10.1371/journal.pone.0182378] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022] Open
Abstract
Background Increased airway smooth muscle is observed in large and small airways in asthma. Semi-quantitative estimates suggest that cells containing alpha smooth muscle actin (α-SMA) are also increased in the lung parenchyma. This study quantified and characterized α-SMA positive cells (α-SMA+) in the lung parenchyma of non-asthmatic and asthmatic individuals. Methods Post-mortem sections of peripheral lung from cases of fatal asthma (FA), persons with asthma dying of non-respiratory causes (NFA) and non-asthma control subjects (NAC) were stained for α-SMA, quantified using point-counting and normalised to alveolar basement membrane length and interstitial area. Results α-SMA+ fractional area was increased in alveolar parenchyma in both FA (14.7 ± 2.8% of tissue area) and NFA (13.0 ± 1.2%), compared with NAC (7.4 ± 2.4%), p < 0.05 The difference was greater in upper lobes compared with lower lobes (p < 0.01) in both asthma groups. Similar changes were observed in alveolar ducts and alveolar walls. The electron microscopic features of the α-SMA+ cells were characteristic of myofibroblasts. Conclusions We conclude that in asthma there is a marked increase in α-SMA+ myofibroblasts in the lung parenchyma. The physiologic consequences of this increase are unknown.
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Affiliation(s)
- Stacey R. Boser
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Thais Mauad
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | | | - Ian Mitchell
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Grishma Shrestha
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrea Chiu
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - John Butt
- Pathfinder Forum, Forensic Pathology, Vancouver, British Columbia, Canada
| | - Margaret M. Kelly
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Elia Caldini
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Alan James
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Francis H. Y. Green
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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8
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Brown RH, Henderson RJ, Sugar EA, Holbrook JT, Wise RA. Reproducibility of airway luminal size in asthma measured by HRCT. J Appl Physiol (1985) 2017; 123:876-883. [PMID: 28705995 DOI: 10.1152/japplphysiol.00307.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/16/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022] Open
Abstract
Brown RH, Henderson RJ, Sugar EA, Holbrook JT, Wise RA, on behalf of the American Lung Association Airways Clinical Research Centers. Reproducibility of airway luminal size in asthma measured by HRCT. J Appl Physiol 123: 876-883, 2017. First published July 13, 2017; doi:10.1152/japplphysiol.00307.2017.-High-resolution CT (HRCT) is a well-established imaging technology used to measure lung and airway morphology in vivo. However, there is a surprising lack of studies examining HRCT reproducibility. The CPAP Trial was a multicenter, randomized, three-parallel-arm, sham-controlled 12-wk clinical trial to assess the use of a nocturnal continuous positive airway pressure (CPAP) device on airway reactivity to methacholine. The lack of a treatment effect of CPAP on clinical or HRCT measures provided an opportunity for the current analysis. We assessed the reproducibility of HRCT imaging over 12 wk. Intraclass correlation coefficients (ICCs) were calculated for individual airway segments, individual lung lobes, both lungs, and air trapping. The ICC [95% confidence interval (CI)] for airway luminal size at total lung capacity ranged from 0.95 (0.91, 0.97) to 0.47 (0.27, 0.69). The ICC (95% CI) for airway luminal size at functional residual capacity ranged from 0.91 (0.85, 0.95) to 0.32 (0.11, 0.65). The ICC measurements for airway distensibility index and wall thickness were lower, ranging from poor (0.08) to moderate (0.63) agreement. The ICC for air trapping at functional residual capacity was 0.89 (0.81, 0.94) and varied only modestly by lobe from 0.76 (0.61, 0.87) to 0.95 (0.92, 0.97). In stable well-controlled asthmatic subjects, it is possible to reproducibly image unstimulated airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability.NEW & NOTEWORTHY There is a surprising lack of studies examining the reproducibility of high-resolution CT in asthma. The current study examined reproducibility of airway measurements. In stable well-controlled asthmatic subjects, it is possible to reproducibly image airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability.
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Affiliation(s)
- Robert H Brown
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland; .,Department of Radiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland.,Division of Pulmonary Medicine, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland.,Department of Environmental Health and Engineering, The Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Robert J Henderson
- Department of Epidemiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Elizabeth A Sugar
- Department of Biostatistics, The Johns Hopkins Medical Institutions, Baltimore, Maryland; and
| | - Janet T Holbrook
- Department of Epidemiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Robert A Wise
- Division of Pulmonary Medicine, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland
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9
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Nieuwenhuis MAE, Vonk JM, Himes BE, Sarnowski C, Minelli C, Jarvis D, Bouzigon E, Nickle DC, Laviolette M, Sin D, Weiss ST, van den Berge M, Koppelman GH, Postma DS. PTTG1IP and MAML3, novel genomewide association study genes for severity of hyperresponsiveness in adult asthma. Allergy 2017; 72:792-801. [PMID: 27709636 DOI: 10.1111/all.13062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2016] [Indexed: 01/15/2023]
Abstract
BACKGROUND The severity of bronchial hyperresponsiveness (BHR) is a fundamental feature of asthma. The severity of BHR varies between asthmatics and is associated with lack of asthma control. The mechanisms underlying this trait are still unclear. This study aimed to identify genes associated with BHR severity, using a genomewide association study (GWAS) on the slope of BHR in adult asthmatics. METHODS We performed a GWAS on BHR severity in adult asthmatics from the Dutch Asthma GWAS cohort (n = 650), adjusting for smoking and inhaled corticosteroid use, and verified results in three other cohorts. Furthermore, we performed eQTL and co-expression analyses in lung tissue. RESULTS In the discovery cohort, one genomewide significant hit located in phosphodiesterase 4D, cAMP-specif (PDE4D) and 26 SNPs with P-values < 1*10-5 were found. None of our findings replicated in adult and childhood replication cohorts jointly. In adult cohorts separately, rs1344110 in pituitary tumour-transforming 1 interacting protein (PTTG1IP) and rs345983 in Mastermind-like 3 (MAML3) replicated nominally; minor alleles of rs345983 and rs1344110 were associated with less severe BHR and higher lung tissue gene expression. PTTG1IP showed significant co-expression with pituitary tumour-transforming 1, the binding factor of PTTG1lP, and with vimentin and E-cadherin1. MAML3 co-expressed significantly with Mastermind-like 2 (MAML2), both involved in Notch signalling. CONCLUSIONS PTTG1IP and MAML3 are associated with BHR severity in adult asthma. The relevance of these genes is supported by the eQTL analyses and co-expression of PTTG1lP with vimentin and E-cadherin1, and MAML3 with MAML2.
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Affiliation(s)
- M. A. E. Nieuwenhuis
- Department of Pulmonary Diseases; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC); University Medical Center Groningen; University of Groningen; Groningen The Netherlands
| | - J. M. Vonk
- Groningen Research Institute for Asthma and COPD (GRIAC); University Medical Center Groningen; University of Groningen; Groningen The Netherlands
- Department of Epidemiology; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
| | - B. E. Himes
- Department of Biostatistics and Epidemiology; University of Pennsylvania; Philadelphia PA USA
| | - C. Sarnowski
- Genetic Variation and Human Diseases Unit; U946; INSERM; Paris France
- Institut Universitaire d'Hématologie; Université Paris Diderot, Sorbonne Paris Cité; Paris France
| | - C. Minelli
- Respiratory Epidemiology, Occupational Medicine and Public Health; National Heart and Lung Institute; Imperial College; London UK
| | - D. Jarvis
- Respiratory Epidemiology, Occupational Medicine and Public Health; National Heart and Lung Institute; Imperial College; London UK
- MRC-PHE Centre for Environment & Health; London UK
| | - E. Bouzigon
- Genetic Variation and Human Diseases Unit; U946; INSERM; Paris France
- Institut Universitaire d'Hématologie; Université Paris Diderot, Sorbonne Paris Cité; Paris France
| | | | - M. Laviolette
- Institut Universitaire de Cardiologie et de Pneumologie de Québec; Laval University; Québec City QC Canada
| | - D. Sin
- The University of British Columbia James Hogg Research Laboratory; St Paul's Hospital; Vancouver BC Canada
- 7 Respiratory Division; Department of Medicine; University of British Columbia; Vancouver BC Canada
| | - S. T. Weiss
- Channing Division of Network Medicine; Department of Medicine; Brigham & Women's Hospital and Harvard Medical School; Boston MA USA
| | - M. van den Berge
- Department of Pulmonary Diseases; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC); University Medical Center Groningen; University of Groningen; Groningen The Netherlands
| | - G. H. Koppelman
- Groningen Research Institute for Asthma and COPD (GRIAC); University Medical Center Groningen; University of Groningen; Groningen The Netherlands
- Department of Pediatric Pulmonology and Pediatric Allergology; Beatrix Children's Hospital; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
| | - D. S. Postma
- Department of Pulmonary Diseases; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC); University Medical Center Groningen; University of Groningen; Groningen The Netherlands
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10
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Brown RH, Togias A. Measurement of intraindividual airway tone heterogeneity and its importance in asthma. J Appl Physiol (1985) 2016; 121:223-32. [PMID: 27103654 PMCID: PMC4967252 DOI: 10.1152/japplphysiol.00545.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 04/20/2016] [Indexed: 11/22/2022] Open
Abstract
While airways have some degree of baseline tone, the level and variability of this tone is not known. It is also unclear whether there is a difference in airway tone or in the variability of airway tone between asthmatic and healthy individuals. This study examined airway tone and intraindividual airway tone heterogeneity (variance of airway tone) in vivo in 19 individuals with asthma compared with 9 healthy adults. All participants underwent spirometry, body plethysmography, and high-resolution computed tomography at baseline and after maximum bronchodilation with albuterol. Airway tone was defined as the percent difference in airway diameter after albuterol at total lung capacity compared with baseline. The amount of airway tone in each airway varied both within and between subjects. The average airway tone did not differ significantly between the two groups (P = 0.09), but the intraindividual airway tone heterogeneity did (P = 0.016). Intraindividual airway tone heterogeneity was strongly correlated with airway tone (r = 0.78, P < 0.0001). Also, it was negatively correlated with the magnitude of the distension of the airways from functional residual capacity to total lung capacity at both baseline (r = −0.49, P = 0.03) and after maximum bronchodilation (r = −0.51, P = 0.02) in the asthma, but not the healthy group. However, we did not find any relationship between intraindividual airway tone heterogeneity and conventional lung function outcomes. Intraindividual airway tone heterogeneity appears to be an important characteristic of airway pathophysiology in asthma.
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Affiliation(s)
- Robert H Brown
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland; Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland; Department of Environmental Health Sciences, Division of Physiology, Johns Hopkins University, Baltimore, Maryland; Department of Radiology, Johns Hopkins University, Baltimore, Maryland; and
| | - Alkis Togias
- Department of Medicine, Divisions of Allergy and Clinical Immunology and Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
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11
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Donovan C, Royce SG, Esposito J, Tran J, Ibrahim ZA, Tang MLK, Bailey S, Bourke JE. Differential effects of allergen challenge on large and small airway reactivity in mice. PLoS One 2013; 8:e74101. [PMID: 24040180 PMCID: PMC3765301 DOI: 10.1371/journal.pone.0074101] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 07/30/2013] [Indexed: 01/21/2023] Open
Abstract
The relative contributions of large and small airways to hyperresponsiveness in asthma have yet to be fully assessed. This study used a mouse model of chronic allergic airways disease to induce inflammation and remodelling and determine whether in vivo hyperresponsiveness to methacholine is consistent with in vitro reactivity of trachea and small airways. Balb/C mice were sensitised (days 0, 14) and challenged (3 times/week, 6 weeks) with ovalbumin. Airway reactivity was compared with saline-challenged controls in vivo assessing whole lung resistance, and in vitro measuring the force of tracheal contraction and the magnitude/rate of small airway narrowing within lung slices. Increased airway inflammation, epithelial remodelling and fibrosis were evident following allergen challenge. In vivo hyperresponsiveness to methacholine was maintained in isolated trachea. In contrast, methacholine induced slower narrowing, with reduced potency in small airways compared to controls. In vitro incubation with IL-1/TNFα did not alter reactivity. The hyporesponsiveness to methacholine in small airways within lung slices following chronic ovalbumin challenge was unexpected, given hyperresponsiveness to the same agonist both in vivo and in vitro in tracheal preparations. This finding may reflect the altered interactions of small airways with surrounding parenchymal tissue after allergen challenge to oppose airway narrowing and closure.
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Affiliation(s)
- Chantal Donovan
- Lung Health Research Centre, Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Simon G. Royce
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Allergy & Immunology, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - James Esposito
- Lung Health Research Centre, Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Jenny Tran
- Lung Health Research Centre, Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Zaridatul Aini Ibrahim
- Lung Health Research Centre, Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Mimi L. K. Tang
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Allergy & Immunology, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Simon Bailey
- Lung Health Research Centre, Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia
| | - Jane E. Bourke
- Lung Health Research Centre, Department of Pharmacology & Therapeutics, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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12
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Kaczka DW, Mitzner W, Brown RH. Effects of lung inflation on airway heterogeneity during histaminergic bronchoconstriction. J Appl Physiol (1985) 2013; 115:626-33. [PMID: 23813528 DOI: 10.1152/japplphysiol.00476.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung inflation has been shown to dilate airways by altering the mechanical equilibrium between opposing airway and parenchymal forces. However, it is not known how heterogeneously such dilation occurs throughout the airway tree. In six anesthetized dogs, we measured the diameters of five to six central airway segments using high-resolution computed tomography, along with respiratory input impedance (Zrs) during generalized aerosol histamine challenge, and local histamine challenge in which the agonist was instilled directly onto the epithelia of the imaged central airways. Airway diameters and Zrs were measured at 12 and 25 cmH2O. The Zrs spectra were fitted with a model that incorporated continuous distributions of airway resistances. Airway heterogeneity was quantified using the coefficient of variation for predefined airway distribution functions. Significant reductions in average central airway diameter were observed at 12 cmH2O for both aerosolized and local challenges, along with significant increases upon inflation to 25 cmH2O. No significant differences were observed for the coefficient of variation of airway diameters under any condition. Significant increases in effective airway resistance as measured by Zrs were observed only for the aerosolized challenge at 12 cmH2O, which was completely reversed upon inflation. We conclude that the lung periphery may be the most dominant contributor to increases in airway resistance and tissue elastance during bronchoconstriction induced by aerosolized histamine. However, isolated constriction of only a few central airway segments may also affect tissue stiffness via interdependence with their surrounding parenchyma.
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13
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Toledo AC, Sakoda CPP, Perini A, Pinheiro NM, Magalhães RM, Grecco S, Tibério IFLC, Câmara NO, Martins MA, Lago JHG, Prado CM. Flavonone treatment reverses airway inflammation and remodelling in an asthma murine model. Br J Pharmacol 2013; 168:1736-49. [PMID: 23170811 PMCID: PMC3605879 DOI: 10.1111/bph.12062] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 10/28/2012] [Accepted: 11/05/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Asthma is an inflammatory disease that involves airway hyperresponsiveness and remodelling. Flavonoids have been associated to anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment of asthma. Our aim was to evaluate the effects of the sakuranetin treatment in several aspects of experimental asthma model in mice. EXPERIMENTAL APPROACH Male BALB/c mice received ovalbumin (i.p.) on days 0 and 14, and were challenged with aerolized ovalbumin 1% on days 24, 26 and 28. Ovalbumin-sensitized animals received vehicle (saline and dimethyl sulfoxide, DMSO), sakuranetin (20 mg kg(-1) per mice) or dexamethasone (5 mg kg(-1) per mice) daily beginning from 24th to 29th day. Control group received saline inhalation and nasal drop vehicle. On day 29, we determined the airway hyperresponsiveness, inflammation and remodelling as well as specific IgE antibody. RANTES, IL-5, IL-4, Eotaxin, IL-10, TNF-α, IFN-γ and GMC-SF content in lung homogenate was performed by Bioplex assay, and 8-isoprostane and NF-kB activations were visualized in inflammatory cells by immunohistochemistry. KEY RESULTS We have demonstrated that sakuranetin treatment attenuated airway hyperresponsiveness, inflammation and remodelling; and these effects could be attributed to Th2 pro-inflammatory cytokines and oxidative stress reduction as well as control of NF-kB activation. CONCLUSIONS AND IMPLICATIONS These results highlighted the importance of counteracting oxidative stress by flavonoids in this asthma model and suggest sakuranetin as a potential candidate for studies of treatment of asthma.
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Affiliation(s)
- A C Toledo
- Departments of Medicine, School of Medicine, University de São Paulo, São Paulo, Brazil
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14
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Pascoe C, Jiao Y, Seow CY, Paré PD, Bossé Y. Force oscillations simulating breathing maneuvers do not prevent force adaptation. Am J Respir Cell Mol Biol 2012; 47:44-9. [PMID: 22323367 DOI: 10.1165/rcmb.2011-0429oc] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Airway inflammation in patients with asthma exposes the airway smooth muscle (ASM) to a variety of spasmogens. These spasmogens increase ASM tone, which can lead to force adaptation. Length oscillations of ASM, which occur in vivo due to breathing maneuvers, can attenuate force adaptation. However, in the presence of tone, the force oscillations required to achieve these length oscillations may be unphysiologic (i.e., magnitude greater than the ones achieved due to the swings in transpulmonary pressure required for breathing). In the present study, we applied force oscillations simulating the tension oscillations experienced by the wall of a fourth-generation airway during tidal breathing with or without deep inspirations (DI) to ASM. The goal was to investigate whether force adaptation occurs in conditions mimicking breathing maneuvers. Tone was induced by carbachol (average, 20 nM), and the force-generating capacity of the ASM was assessed at 5-minute intervals before and after carbachol administration using electrical field stimulations (EFS). The results show that force oscillations applied before the introduction of tone had a small effect on the force produced by EFS (declined to 96.8% [P > 0.05] and 92.3% [P < 0.05] with and without DI, respectively). The tone induced by carbachol transiently decreased after a DI and declined significantly (P < 0.05) due to tidal breathing oscillations (25%). These force oscillations did not prevent force adaptation (gain of force of 11.2 ± 2.2 versus 13.5 ± 2.7 and 11.2 ± 3.0% in static versus dynamic conditions with or without DI, respectively). The lack of effect of simulated breathing maneuvers on force adaptation suggests that this gain in ASM force may occur in vivo and could contribute to the development of airway hyperresponsiveness.
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Affiliation(s)
- Chris Pascoe
- University of British Columbia, James Hogg Research Center, St. Paul’s Hospital Vancouver, Canada
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