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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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Kostorz-Nosal S, Jastrzębski D, Błach A, Skoczyński S. Window of opportunity for respiratory oscillometry: A review of recent research. Respir Physiol Neurobiol 2023; 316:104135. [PMID: 37536553 DOI: 10.1016/j.resp.2023.104135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/19/2023] [Accepted: 07/30/2023] [Indexed: 08/05/2023]
Abstract
Oscillometry has been around for almost 70 years, but there are still many unknowns. The test is performed during tidal breathing and is therefore free from patient-dependent factors that could influence the results. The Forced Oscillation Technique (FOT), which requires minimal patient cooperation, is gaining ground, particularly with elderly patients and children. In pulmonology, it is a valuable tool for assessing obstructive conditions (with a distinction between central and peripheral obstruction) and restrictive disorders (intrapulmonary and extrapulmonary). Its sensitivity allows the assessment of bronchodilator and bronchoconstrictor responses. Different lung diseases show different patterns of changes in FOT, especially studied in asthma and chronic obstructive pulmonary disease. Because of these differences, many studies have analysed the usefulness of this technique in different areas of medicine. In this paper, the authors would like to present the basics of oscillometry with the areas of its most recent clinical applications.
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Affiliation(s)
- Sabina Kostorz-Nosal
- Department of Lung Diseases and Tuberculosis, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, 41-803 Zabrze, Poland.
| | - Dariusz Jastrzębski
- Department of Lung Diseases and Tuberculosis, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, 41-803 Zabrze, Poland
| | - Anna Błach
- Department of Cardiology and Structural Heart Diseases, Medical University of Silesia, Katowice, Poland
| | - Szymon Skoczyński
- Department of Lung Diseases and Tuberculosis, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, 41-803 Zabrze, Poland
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Henry C, Boucher M, Boulay MÈ, Côté A, Boulet LP, Bossé Y. The cumulative effect of methacholine on large and small airways when deep inspirations are avoided. Respirology 2023; 28:226-235. [PMID: 36210352 DOI: 10.1111/resp.14387] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 09/20/2022] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND OBJECTIVE The effect of serial incremental concentrations of methacholine is only slightly cumulative when assessed by spirometry. This limited cumulative effect may be attributed to the bronchodilator effect of deep inspirations that are required between concentrations to measure lung function. Using oscillometry, the response to methacholine can be measured without deep inspirations. Conveniently, oscillometry can also dissociate the contribution of large versus small airways. Herein, oscillometry was used to assess the cumulative effect of methacholine in the absence of deep inspirations on large and small airways. METHODS Healthy and asthmatic volunteers underwent a multiple-concentration methacholine challenge on visit 1 and a single-concentration challenge on visit 2 using the highest concentration of visit 1. The maximal response was compared between visits to assess the cumulative effect of methacholine. The lung volume was also measured after the final concentration to assess hyperinflation. RESULTS In both healthy and asthmatic subjects, increases in resistance at 19 Hz (Rrs19 ), reflecting large airway narrowing, did not differ between the multiple- and the single-concentration challenge. However, increases in resistance at 5 Hz (Rrs5 ) minus Rrs19 , reflecting small airway narrowing, were 117 and 270% greater in the multiple- than the single-concentration challenge in healthy (p = 0.006) and asthmatic (p < 0.0001) subjects, respectively. Hyperinflation occurred with both challenges and was greater in the multiple- than the single-concentration challenge in both groups. CONCLUSION Without deep inspirations, the effect of methacholine is cumulative on small airways but not on large airways. Lung hyperinflation and derecruitment may partially explain these different responses.
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Affiliation(s)
- Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec, Canada
| | - Marie-Ève Boulay
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec, Canada
| | - Andréanne Côté
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec, Canada
| | | | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec, Canada
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Kraemer R, Gardin F, Smith HJ, Baty F, Barandun J, Piecyk A, Minder S, Salomon J, Frey M, Brutsche MH, Matthys H. Functional Predictors Discriminating Asthma-COPD Overlap (ACO) from Chronic Obstructive Pulmonary Disease (COPD). Int J Chron Obstruct Pulmon Dis 2022; 17:2723-2743. [PMID: 36304971 PMCID: PMC9595126 DOI: 10.2147/copd.s382761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022] Open
Abstract
Background A significant proportion of patients with obstructive lung disease have clinical and functional features of both asthma and chronic obstructive pulmonary disease (COPD), referred to as the asthma-COPD overlap (ACO). The distinction of these phenotypes, however, is not yet well-established due to the lack of defining clinical and/or functional criteria. The aim of our investigations was to assess the discriminating power of various lung function parameters on the assessment of ACO. Methods From databases of 4 pulmonary centers, a total of 540 patients (231 males, 309 females), including 372 patients with asthma, 77 patients with ACO and 91 patients with COPD, were retrospectively collected, and gradients among combinations of explanatory variables of spirometric (FEV1, FEV1/FVC, FEF25-75), plethysmographic (sReff, sGeff, the aerodynamic work of breathing at rest; sWOB), static lung volumes, including trapped gases and measurements of the carbon monoxide transfer (DLCO, KCO) were explored using multiple factor analysis (MFA). The discriminating power of lung function parameters with respect to ACO was assessed using linear discriminant analysis (LDA). Results LDA revealed that parameters of airway dynamics (sWOB, sReff, sGeff) combined with parameters of static lung volumes such as functional residual capacity (FRCpleth) and trapped gas at FRC (VTG FRC) are valuable and potentially important tools discriminating between asthma, ACO and COPD. Moreover, sWOB significantly contributes to the diagnosis of obstructive airway diseases, independent from the state of pulmonary hyperinflation, whilst the diffusion capacity for carbon monoxide (DLCO) significantly differentiates between the 3 diagnostic classes. Conclusion The complexity of COPD with its components of interaction and their heterogeneity, especially in discrimination from ACO, may well be differentiated if patients are explored by a whole set of target parameters evaluating, interactionally, flow limitation, airway dynamics, pulmonary hyperinflation, small airways dysfunction and gas exchange disturbances assessing specific functional deficits.
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Affiliation(s)
- Richard Kraemer
- Centre of Pulmonary Medicine, Hirslanden Private Hospital Group, Salem-Hospital, Bern, Switzerland
- Center for Translational Medicine and Biomedical Entrepreneurship, University of Bern, Bern, Switzerland
| | - Fabian Gardin
- Centre of Pulmonary Medicine, Hirslanden Private Hospital Group, Clinic Hirslanden, Zürich, Switzerland
| | - Hans-Jürgen Smith
- Medical Development, Research in Respiratory Diagnostics, Berlin, Germany
| | - Florent Baty
- Department of Pneumology, Cantonal Hospital St, Gallen, Switzerland
| | - Jürg Barandun
- Centre of Pulmonary Medicine, Hirslanden Private Hospital Group, Clinic Hirslanden, Zürich, Switzerland
| | - Andreas Piecyk
- Centre of Pulmonary Medicine, Hirslanden Private Hospital Group, Clinic Hirslanden, Zürich, Switzerland
| | - Stefan Minder
- Centre of Pulmonary Medicine, Hirslanden Private Hospital Group, Salem-Hospital, Bern, Switzerland
| | - Jörg Salomon
- Centre of Pulmonary Medicine, Hirslanden Private Hospital Group, Salem-Hospital, Bern, Switzerland
| | - Martin Frey
- Department of Pneumology, Barmelweid Hospital, Barmelweid, Switzerland
| | | | - Heinrich Matthys
- Department of Pneumology, University Hospital of Freiburg, Freiburg, Germany
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Which Therapy for Non-Type(T)2/T2-Low Asthma. J Pers Med 2021; 12:jpm12010010. [PMID: 35055325 PMCID: PMC8779705 DOI: 10.3390/jpm12010010] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/13/2021] [Accepted: 12/22/2021] [Indexed: 12/17/2022] Open
Abstract
Currently, the asthmatic population is divided into Type 2-high and non-Type 2/Type 2-low asthmatics, with 50% of patients belonging to one of the two groups. Differently from T2-high, T2-low asthma has not been clearly defined yet, and the T2-low patients are identified on the basis of the absence or non-predominant expression of T2-high biomarkers. The information about the molecular mechanisms underpinning T2-low asthma is scarce, but researchers have recognized as T2-low endotypes type 1 and type 3 immune response, and remodeling events occurring without inflammatory processes. In addition, the lack of agreed biomarkers reprents a challenge for the research of an effective therapy. The first-choice medication is represented by inhaled corticosteroids despite a low efficacy is reported for/in T2-low patients. However, macrolides and long-acting anti-muscarinic drugs have been recognized as efficacious. In recent years, clinical trials targeting biomarkers playing key roles in T3 and T1 immune pathways, alarmins, and molecules involved in neutrophil recruitment have provided conflicting results probably misleading (or biased) in patients' selection. However, further studies are warranted to achieve a precise characterization of T2-low asthma with the aim of defining a tailored therapy for each single asthmatic patient.
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Pabst R. The bronchus-associated-lymphoid tissue (BALT) an unique lymphoid organ in man and animals. Ann Anat 2021; 240:151833. [PMID: 34670121 DOI: 10.1016/j.aanat.2021.151833] [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] [Received: 07/16/2021] [Revised: 08/27/2021] [Accepted: 08/29/2021] [Indexed: 01/10/2023]
Abstract
The development structure and number of bronchus-associated lymphoid tissue (BALT) will be described in many different animals (like chicken, rabbit, mouse, rat, farm animals and particular the pig, monkey) and these data compared to healthy man and in human diseases. The term induced BALT should not be used because it is a tertiary lymphoid structure, which lacks the contact to a bronchus and does not consist of the important area (dome area) which is essential for antigen uptake of microbial stimuli, which are essential in the development of BALT. Mycoplasma seems to play a critical role as shown in pigs but there not been documented in other species like rabbits. More studies have to be performed in health and disease (e.g. in apes) to document the structural and functional basis to use BALT as an entry site for vaccination protocols.
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Affiliation(s)
- Reinhard Pabst
- Immunomorphology, Centre of Anatomy, Medical School Hannover, Germany.
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Kraemer R, Smith HJ, Gardin F, Barandun J, Minder S, Kern L, Brutsche MH. Bronchodilator Response in Patients with COPD, Asthma-COPD-Overlap (ACO) and Asthma, Evaluated by Plethysmographic and Spirometric z-Score Target Parameters. Int J Chron Obstruct Pulmon Dis 2021; 16:2487-2500. [PMID: 34511893 PMCID: PMC8420556 DOI: 10.2147/copd.s319220] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/02/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Airflow reversibility criteria in COPD are still debated - especially in situations of co-existing COPD and asthma. Bronchodilator response (BDR) is usually assessed by spirometric parameters. Changes assessed by plethysmographic parameters such as the effective, specific airway conductance (sGeff), and changes in end-expiratory resting level at functional residual capacity (FRCpleth) are rarely appreciated. We aimed to assess BDR by spirometric and concomitantly measured plethysmographic parameters. Moreover, BDR on the specific aerodynamic work of breathing (sWOB) was evaluated. METHODS From databases of 3 pulmonary centers, BDR to 200 g salbutamol was retrospectively evaluated by spirometric (∆FEV1 and ∆FEF25-75), and plethysmographic (∆sGeff, ∆FRCpleth, and ∆sWOB) parameters in a total of 843 patients diagnosed as COPD (478 = 57%), asthma-COPD-overlap (ACO) (139 = 17%), or asthma (226 = 27%), encountering 1686 BDR-measurement-sets (COPD n = 958; ACO n = 276; asthma n = 452). RESULTS Evaluating z-score improvement taking into consideration the whole pre-test z-score range, highest BDR was achieved by combining ∆sGeff and ∆FRC detecting BDR in 62.2% (asthma: 71.4%; ACO: 56.7%; COPD: 59.8%), by ∆sGeff in 53.4% (asthma: 69.1%; ACO: 51.6%; COPD: 47.4%), whereas ∆FEV1 only distinguished in 10.6% (asthma: 21.8%; ACO: 18.6%; COPD: 4.2%). Remarkably, ∆sWOB detected BDR in 49.4% (asthma: 76.2%; ACO: 47.8%; COPD: 46.9%). CONCLUSION BDR largely depends on the pre-test functional severity and, therefore, should be evaluated in relation to the pre-test conditions expressed as ∆z-scores, considering changes in airway dynamics, changes in static lung volumes and changes in small airway function. Plethysmographic parameters demonstrated BDR at a significant higher rate than spirometric parameters.
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Affiliation(s)
- Richard Kraemer
- Center of Pulmonary Medicine, Hirslanden Private Hospital Group, Salem-Hospital, Bern, Switzerland
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Hans-Jürgen Smith
- Medical Development, Research in Respiratory Diagnostics, Berlin, Germany
| | - Fabian Gardin
- Center of Pulmonary Medicine, Hirslanden Private Hospital Group, Clinic Hirslanden, Zürich, Switzerland
| | - Jürg Barandun
- Center of Pulmonary Medicine, Hirslanden Private Hospital Group, Clinic Hirslanden, Zürich, Switzerland
| | - Stefan Minder
- Medical Development, Research in Respiratory Diagnostics, Berlin, Germany
| | - Lukas Kern
- Clinic of Pneumology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Martin H Brutsche
- Clinic of Pneumology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
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8
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Kraemer R, Smith H, Matthys H. Normative reference equations of airway dynamics assessed by whole-body plethysmography during spontaneous breathing evaluated in infants, children, and adults. Physiol Rep 2021; 9:e15027. [PMID: 34514738 PMCID: PMC8436055 DOI: 10.14814/phy2.15027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/10/2021] [Accepted: 08/15/2021] [Indexed: 11/24/2022] Open
Abstract
Effective specific airway resistance (sReff ), its reciprocal the effective specific airway conductance (sGeff ) are computed as ratios between the integral of the resistive aerodynamic work of breathing (sWOB) and the integral of the tidal flow/volume loop, the reciprocal, respectively. Unfortunately, reference equations to obtain normative values for sReff , sGeff , and sWOB are not yet available. To assess reference equations for sWOB, sReff , and sGeff during tidal breathing at resting level in healthy infants, children, and adults by a multidimensional model. Retrospectively exported data were collected from databases of five Swiss lung function centers, in which plethysmography (Jaeger Würzburg, Germany) was performed for the assessment of airway dynamics, static lung volumes, and forced breathing flow-volume loops, in a collective of 28 healthy infants, 47 children, and 273 adults. From this cohort, reference equations were computed based on anthropometric measures, lung volumes, indices of the breathing pattern, and timing of breathing. By multi-linear modeling reference equations of sReff , sGeff , and sWOB could be defined taking as independent parameters apart from anthropometric parameters, also parameters given by the ratio between the tidal volume and functional residual capacity (FRCpleth /VT ), and the ratio between VT and inspiratory time (VT /TI ). An alternative statistical approach to define reference equations of airway dynamics reveals that apart from the subject's anthropometric measurements, parameters of the magnitude of static lung volumes, the breathing pattern, and the timing of breathing are co-variants of reference equations of airway dynamics over a large age range.
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Affiliation(s)
- Richard Kraemer
- Centre of Pulmonary MedicineHirslanden Private Hospital GroupSalem‐HospitalBernSwitzerland
- Department of PaediatricsUniversity of BernBernSwitzerland
- Department of Biomedical ResearchUniversity of BernBernSwitzerland
| | | | - Heinrich Matthys
- Department of PneumologyUniversity Hospital of FreiburgFreiburgGermany
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Gray‐Miceli D, Rogowski J, de Cordova PB, Boltz M. A framework for delivering nursing care to older adults with COVID-19 in nursing homes. Public Health Nurs 2021; 38:610-626. [PMID: 33715193 PMCID: PMC8251143 DOI: 10.1111/phn.12885] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 11/29/2022]
Abstract
Public health emergencies threaten the lives of U.S. citizens, often in disproportionate ways. Hardest hit are vulnerable populations of older adults (OAs) residing in nursing homes (NHs), who comprised nearly 43% of all deaths from COVID-19 in NHs in 2020. New Jersey (NJ) ranks #2 nationally behind New York with the highest numbers of resident deaths; more than 50% of all COVID-19-related deaths in NJ have occurred in NHs. This public health emergency has prompted investigators to evaluate existing structural, resident, process of care, regulatory, and policy characteristics that have impacted the delivery of nursing care within NJ NHs. In this manuscript, we discuss data from NJ NHs during COVID-19, drawing from publicly available data, state reports, and the geriatric literature to offer recommendations. Based on evidence-based practices (EBPs), we present a series of recommendations to modify existing contextual factors in NHs to best prepare for the next health disaster.
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Affiliation(s)
- Deanna Gray‐Miceli
- Jefferson College of Nursing, Thomas Jefferson UniversityPhiladelphiaPAUSA
| | - Jeannette Rogowski
- Department of Health Policy and AdministrationThe Pennsylvania State UniversityUniversity ParkPAUSA
| | | | - Marie Boltz
- Penn State College of NursingUniversity ParkPAUSA
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10
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Svenningsen S, Nair P. There is more to severe asthma associated with obesity than inflammation. Respirology 2021; 26:288-289. [PMID: 33561886 DOI: 10.1111/resp.14012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 01/21/2023]
Affiliation(s)
- Sarah Svenningsen
- Division of Respirology, Department of Medicine, McMaster University and St Joseph's Healthcare Hamilton, Hamilton, ON, Canada
| | - Parameswaran Nair
- Division of Respirology, Department of Medicine, McMaster University and St Joseph's Healthcare Hamilton, Hamilton, ON, Canada
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Porojan-Suppini N, Fira-Mladinescu O, Marc M, Tudorache E, Oancea C. Lung Function Assessment by Impulse Oscillometry in Adults. Ther Clin Risk Manag 2020; 16:1139-1150. [PMID: 33273817 PMCID: PMC7705955 DOI: 10.2147/tcrm.s275920] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/08/2020] [Indexed: 11/23/2022] Open
Abstract
Over the past decades, impulse oscillometry (IOS) has gained ground in the battery of pulmonary function tests. Performing the test requires minimal cooperation of the patient; therefore, it is a useful tool, especially in evaluating lung mechanics in children, elderly patients, and those who cannot perform spirometry. Oscillometry has also been used in both clinical and research departments. Studies were published mainly in asthma regarding detection of bronchodilator response and the therapeutic response to different drugs. Furthermore, it has been shown to be a sensitive technique to evaluate disease control. Other studied diseases were COPD, interstitial lung diseases, small airway disease, impairment of lung function due to exposure to occupational hazards or smoking, central airways obstruction, cystic fibrosis, monitoring lung mechanics during mechanical ventilation and sleep, neuromuscular diseases, lung transplant, and graft function. The aim of this review is to present the utility of oscillometry on the previously mentioned clinical fields.
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Affiliation(s)
- Noemi Porojan-Suppini
- Department of Pulmonology, Center for Research and Innovation in Personalized Medicine of Respiratory Diseases, University of Medicine and Pharmacy "Victor Babeș", Timișoara, Romania
| | - Ovidiu Fira-Mladinescu
- Department of Pulmonology, Center for Research and Innovation in Personalized Medicine of Respiratory Diseases, University of Medicine and Pharmacy "Victor Babeș", Timișoara, Romania
| | - Monica Marc
- Department of Pulmonology, Center for Research and Innovation in Personalized Medicine of Respiratory Diseases, University of Medicine and Pharmacy "Victor Babeș", Timișoara, Romania
| | - Emanuela Tudorache
- Department of Pulmonology, Center for Research and Innovation in Personalized Medicine of Respiratory Diseases, University of Medicine and Pharmacy "Victor Babeș", Timișoara, Romania
| | - Cristian Oancea
- Department of Pulmonology, Center for Research and Innovation in Personalized Medicine of Respiratory Diseases, University of Medicine and Pharmacy "Victor Babeș", Timișoara, Romania
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12
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Wang L, Chitano P, Seow CY. Mechanopharmacology of Rho-kinase antagonism in airway smooth muscle and potential new therapy for asthma. Pharmacol Res 2020; 159:104995. [PMID: 32534100 DOI: 10.1016/j.phrs.2020.104995] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/20/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023]
Abstract
The principle of mechanopharmacology of airway smooth muscle (ASM) is based on the premise that physical agitation, such as pressure oscillation applied to an airway, is able to induce bronchodilation by reducing contractility and softening the cytoskeleton of ASM. Although the underlying mechanism is not entirely clear, there is evidence to suggest that large-amplitude stretches are able to disrupt the actomyosin interaction in the crossbridge cycle and weaken the cytoskeleton in ASM cells. Rho-kinase is known to enhance force generation and strengthen structural integrity of the cytoskeleton during smooth muscle activation and plays a key role in the maintenance of force during prolonged muscle contractions. Synergy in relaxation has been observed when the muscle is subject to oscillatory length change while Rho-kinase is pharmacologically inhibited. In this review, inhibition of Rho-kinase coupled to therapeutic pressure oscillation applied to the airways is explored as a combination treatment for asthma.
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Affiliation(s)
- Lu Wang
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada.
| | - Pasquale Chitano
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada
| | - Chun Y Seow
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada
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13
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Foy BH, Natarajan S, Munawar A, Soares M, Thorpe J, Owers-Bradley J, Siddiqui S. Characterising the role of small airways in severe asthma using low frequency forced oscillations: A combined computational and clinical approach. Respir Med 2020; 170:106022. [PMID: 32843165 DOI: 10.1016/j.rmed.2020.106022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 03/18/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Within asthma, the small airways (≤2 mm in diameter) play an important role in pathophysiology. Using a combined clinical-computational approach, we sought to more precisely evaluate the contribution of the small airways to deep-breath induced airway dilation (in the absence of bronchial challenge), which may be impaired in severe asthma. METHODS A patient-based computational model of the FOT was used to examine the sensitivity and specificity of FOT signals to small airways constriction at frequencies of 2 & 8 Hz. A clinical study of moderate to severe asthmatics (n = 24), and healthy volunteers (n = 10) was performed to evaluate correlations between baseline and post deep inspiration (following bronchodilator withhold and in the absence of prior bronchial challenge) forced oscillation technique (FOT) responses (at 2Hz and 8Hz) and asthma treatment intensity, spirometry, airway hyper-responsiveness and airway inflammation. RESULTS Computational modelling demonstrated that baseline resistance measures at 2Hz are both sensitive and specific to anatomical narrowing in the small airways. Furthermore, small airways resistance was significantly increased in asthmatics compared to health. Despite these differences, there were no noticeable differences between asthmatics and healthy volunteers in resistive measures following deep inspiration (DI) and DI responses of small airways were amplified in the presence of spirometry defined airflow limitation. CONCLUSIONS These results suggest that the small airways demonstrate increased resistance in moderate-to-severe asthma but dilate normally in response to deep inspirations in the absence of bronchial challenge. This suggests that effective targeting of the small airways is required to achieve functional improvements in moderate-severe asthmatic patients.
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Affiliation(s)
- Brody H Foy
- Computational Biology, Department of Computer Science, University of Oxford, Oxford, United Kingdom.
| | - Sushiladevi Natarajan
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, United Kingdom
| | - Arham Munawar
- Cambridge University Hospitals, NHS Foundation Trust, Cambridge, United Kingdom
| | - Marcia Soares
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, United Kingdom
| | - James Thorpe
- School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - John Owers-Bradley
- School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - Salman Siddiqui
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, United Kingdom
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14
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King GG, Bates J, Berger KI, Calverley P, de Melo PL, Dellacà RL, Farré R, Hall GL, Ioan I, Irvin CG, Kaczka DW, Kaminsky DA, Kurosawa H, Lombardi E, Maksym GN, Marchal F, Oppenheimer BW, Simpson SJ, Thamrin C, van den Berge M, Oostveen E. Technical standards for respiratory oscillometry. Eur Respir J 2020; 55:13993003.00753-2019. [PMID: 31772002 DOI: 10.1183/13993003.00753-2019] [Citation(s) in RCA: 282] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022]
Abstract
Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes in this update, compared with the 2003 ERS task force document are 1) new quality control procedures which reflect use of "within-breath" analysis, and methods of handling artefacts; 2) recommendation to disclose signal processing, quality control, artefact handling and breathing protocols (e.g. number and duration of acquisitions) in reports and publications to allow comparability and replication between devices and laboratories; 3) a summary review of new data to support threshold values for bronchodilator and bronchial challenge tests; and 4) updated list of predicted impedance values in adults and children.
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Affiliation(s)
- Gregory G King
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital and The Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Jason Bates
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Kenneth I Berger
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Peter Calverley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Pedro L de Melo
- Institute of Biology and Faculty of Engineering, Department of Physiology, Biomedical Instrumentation Laboratory, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria - DEIB, Politecnico di Milano University, Milano, Italy
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Graham L Hall
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Iulia Ioan
- Dept of Pediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Charles G Irvin
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - David W Kaczka
- Depts of Anesthesia, Biomedical Engineering and Radiology, University of Iowa, Iowa City, IA, USA
| | - David A Kaminsky
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Hajime Kurosawa
- Dept of Occupational Health, Tohoku University School of Medicine, Sendai, Japan
| | - Enrico Lombardi
- Pediatric Pulmonary Unit, Meyer Pediatric University Hospital, Florence, Italy
| | - Geoffrey N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - François Marchal
- Dept of Pediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Beno W Oppenheimer
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Shannon J Simpson
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Cindy Thamrin
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital and The Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Maarten van den Berge
- University of Groningen, University Medical Center Groningen, Dept of Pulmonary Diseases, Groningen, The Netherlands
| | - Ellie Oostveen
- Dept of Respiratory Medicine, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium
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15
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Cockcroft DW, Davis BE, Blais CM. Comparison of methacholine and mannitol challenges: importance of method of methacholine inhalation. Allergy Asthma Clin Immunol 2020; 16:14. [PMID: 32082392 PMCID: PMC7014722 DOI: 10.1186/s13223-020-0410-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/28/2020] [Indexed: 11/24/2022] Open
Abstract
Background Direct inhalation challenges (e.g. methacholine) are stated to be more sensitive and less specific for a diagnosis of asthma than are indirect challenges (e.g. exercise, non-isotonic aerosols, mannitol, etc.). However, data surrounding comparative sensitivity and specificity for methacholine compared to mannitol challenges are conflicting. When methacholine is inhaled by deep total lung capacity (TLC) inhalations, deep inhalation inhibition of bronchoconstriction leads to a marked loss of diagnostic sensitivity when compared to tidal breathing (TB) inhalation methods. We hypothesized that deep inhalation methacholine methods with resulting bronchoprotection may be the explanation for conflicting sensitivity/specificity data. Methods We reviewed 27 studies in which methacholine and mannitol challenges were performed in largely the same individuals. Methacholine was inhaled by dosimeter TLC methods in 13 studies and by tidal breathing in 14 studies. We compared the rates of positive methacholine (stratified by inhalation method) and mannitol challenges in both asthmatics and non-asthmatics. Results When methacholine was inhaled by TLC inhalations the prevalence of positive tests in asthmatics, 60.2% (548/910), was similar to mannitol, 58.9% (537/912). By contrast, when methacholine was inhaled by tidal breathing the prevalence of positive tests in asthmatics 83.1% (343/413) was more than double that of mannitol, 41.5% (146/351). In non-asthmatics, the two methacholine methods resulted in positive tests in 18.8% (142/756) and 16.2% (27/166) by TLC and TB inhalations respectively. This compares to an overall 8.3% (n = 76) positive rate for mannitol in 913 non-asthmatics. Conclusion These data support the hypothesis that the conflicting data comparing methacholine and mannitol sensitivity and specificity are due to the method of methacholine inhalation. Tidal breathing methacholine methods have a substantially greater sensitivity for a diagnosis of asthma than either TLC dosimeter methacholine challenge methods or mannitol challenge. Methacholine challenges should be performed by tidal breathing as per recent guideline recommendations. Methacholine (more sensitive) and mannitol (more specific) will thus have complementary diagnostic features.
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Affiliation(s)
- Donald W Cockcroft
- 1Department of Medicine, University of Saskatchewan, Saskatoon, SK Canada.,2Royal University Hospital, 103 Hospital Drive, Saskatoon, SK S7N0W8 Canada
| | - Beth E Davis
- 1Department of Medicine, University of Saskatchewan, Saskatoon, SK Canada
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16
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Gazzola M, Khadangi F, Clisson M, Beaudoin J, Clavel MA, Bossé Y. Airway smooth muscle adapting in dynamic conditions is refractory to the bronchodilator effect of a deep inspiration. Am J Physiol Lung Cell Mol Physiol 2020; 318:L452-L458. [PMID: 31913645 DOI: 10.1152/ajplung.00270.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Airway smooth muscle (ASM) is continuously strained during breathing at tidal volume. Whether this tidal strain influences the magnitude of the bronchodilator response to a deep inspiration (DI) is not clearly defined. The present in vitro study examines the effect of tidal strain on the bronchodilator effect of DIs. ASM strips from sheep tracheas were mounted in organ baths and then subjected to stretches (30% strain), simulating DIs at varying time intervals. In between simulated DIs, the strips were either held at a fixed length (isometric) or oscillated continuously by 6% (length oscillations) to simulate tidal strain. The contractile state of the strips was also controlled by adding either methacholine or isoproterenol to activate or relax ASM, respectively. Although the time-dependent gain in force caused by methacholine was attenuated by length oscillations, part of the acquired force in the oscillating condition was preserved postsimulated DIs, which was not the case in the isometric condition. Consequently, the bronchodilator effect of simulated DIs (i.e., the decline in force postsimulated versus presimulated DIs) was attenuated in oscillating versus isometric conditions. These findings suggest that an ASM operating in a dynamic environment acquired adaptations that make it refractory to the decline in contractility inflicted by a larger strain simulating a DI.
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Affiliation(s)
- Morgan Gazzola
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada
| | - Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada
| | - Marine Clisson
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada
| | - Jonathan Beaudoin
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada
| | - Marie-Annick Clavel
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada
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17
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Blais CM, Davis BE, Cockcroft DW. The effect of deep inhalation on mannitol responsiveness. Clin Exp Allergy 2019; 50:308-314. [PMID: 31785175 DOI: 10.1111/cea.13543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/01/2019] [Accepted: 11/27/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Mannitol inhalation testing is specific for asthmatics with eosinophilic airway inflammation, a factor that has been negatively correlated with the development of deep inhalation bronchoprotection. OBJECTIVE To evaluate the effect of deep inhalations on responsiveness to inhaled mannitol in correlation with the degree of airway inflammation. METHODS Twenty participants with stable asthma completed this randomized, crossover study. A screening visit assessed responsiveness to methacholine and airway inflammation through fractional exhaled nitric oxide (FeNO) measures and sputum induction. Participants next completed two mannitol challenges, one with deep inhalations (standard method) and one with inhalations to half of total lung capacity, and two methacholine challenges, one with tidal breathing (standard method) and one with deep inhalations. Only the inhalation technique for dose administration differed between repeat mannitol or methacholine challenges. RESULTS Deep inhalations did not significantly influence the provocative dose of mannitol causing a 15% fall in forced expiratory volume in 1 second ((P = .73; n = 7) or the mannitol dose-response slope (P = .26; n = 20). Deep inhalations produced significant bronchoprotection against methacholine (P = .03; n = 20). FeNO levels were significantly correlated to sputum eosinophilia (P = .02; n = 15), responsiveness to deep inhalation methacholine (P = .005; n = 20), the dose-response slopes from deep inhalation mannitol (P = .01; n = 20), and the dose-response slope from non-deep inhalation mannitol (P = .005; n = 20). CONCLUSIONS AND CLINICAL RELEVANCE Deep inhalations did not produce significant bronchoprotection against inhaled mannitol. This result is in agreement with past findings linking airway inflammation with loss of deep inhalation bronchoprotection. CLINICAL TRIAL REGISTRATION This study was prospectively registered on clinicaltrials.gov (NCT03505489).
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Affiliation(s)
- Christianne M Blais
- Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Beth E Davis
- Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Donald W Cockcroft
- Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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18
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Sinha A, Lutter R, Xu B, Dekker T, Dierdorp B, Sterk PJ, Frey U, Eckert ED. Loss of adaptive capacity in asthmatic patients revealed by biomarker fluctuation dynamics after rhinovirus challenge. eLife 2019; 8:47969. [PMID: 31687927 PMCID: PMC6877087 DOI: 10.7554/elife.47969] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 11/04/2019] [Indexed: 12/18/2022] Open
Abstract
Asthma is a dynamic disease, in which lung mechanical and inflammatory processes interact in a complex manner, often resulting in exaggerated physiological, in particular, inflammatory responses to exogenous triggers. We hypothesize that this may be explained by respiratory disease-related systems instability and loss of adaptability to changing environmental conditions, manifested in highly fluctuating biomarkers and symptoms. Using time series of inflammatory (eosinophils, neutrophils, FeNO), clinical and lung function biomarkers (PEF, FVC,FEV1), we estimated this loss of adaptive capacity (AC) during an experimental rhinovirus infection in 24 healthy and asthmatic human volunteers. Loss of AC was estimated by comparing similarities between pre- and post-challenge time series. Unlike healthy participants, the asthmatic’s post-viral-challenge state resembled more other rhinovirus-infected asthmatics than their own pre-viral-challenge state (hypergeometric-test: p=0.029). This reveals loss of AC and supports the concept that in asthma, biological processes underlying inflammatory and physiological responses are unstable, contributing to loss of control.
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Affiliation(s)
- Anirban Sinha
- Department of Respiratory Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Biomedical Engineering and University Children's Hospital, University of Basel, Basel, Switzerland
| | - René Lutter
- Department of Respiratory Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Binbin Xu
- University of Bordeaux, Inserm, Bordeaux Population Health Research Center, UMR 1219, Bordeaux, France
| | - Tamara Dekker
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Barbara Dierdorp
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Peter J Sterk
- Department of Respiratory Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Urs Frey
- Department of Biomedical Engineering and University Children's Hospital, University of Basel, Basel, Switzerland
| | - Edgar Delgado Eckert
- Department of Biomedical Engineering and University Children's Hospital, University of Basel, Basel, Switzerland
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19
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Mast cells drive IgE-mediated disease but might be bystanders in many other inflammatory and neoplastic conditions. J Allergy Clin Immunol 2019; 144:S19-S30. [DOI: 10.1016/j.jaci.2019.07.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 06/11/2019] [Accepted: 07/08/2019] [Indexed: 01/05/2023]
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20
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Gazzola M, Khadangi F, Clisson M, Beaudoin J, Clavel MA, Bossé Y. Shortening of airway smooth muscle is modulated by prolonging the time without simulated deep inspirations in ovine tracheal strips. J Appl Physiol (1985) 2019; 127:1528-1538. [PMID: 31545157 DOI: 10.1152/japplphysiol.00423.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The shortening of airway smooth muscle (ASM) is greatly affected by time. This is because stimuli affecting ASM shortening, such as bronchoactive molecules or the strain inflicted by breathing maneuvers, not only alter quick biochemical processes regulating contraction but also slower processes that allow ASM to adapt to an ever-changing length. Little attention has been given to the effect of time on ASM shortening. The present study investigates the effect of changing the time interval between simulated deep inspirations (DIs) on ASM shortening and its responsiveness to simulated DIs. Excised tracheal strips from sheep were mounted in organ baths and either activated with methacholine or relaxed with isoproterenol. They were then subjected to simulated DIs by imposing swings in distending stress, emulating a transmural pressure from 5 to 30 cmH2O. The simulated DIs were intercalated by 2, 5, 10, or 30 min. In between simulated DIs, the distending stress was either fixed or oscillating to simulate tidal breathing. The results show that although shortening was increased by prolonging the interval between simulated DIs, the bronchodilator effect of simulated DIs (i.e., the elongation of the strip post- vs. pre-DI) was not affected, and the rate of re-shortening post-simulated DIs was decreased. As the frequency with which DIs are taken increases upon bronchoconstriction, our results may be relevant to typical alterations observed in asthma, such as an increased rate of re-narrowing post-DI.NEW & NOTEWORTHY The frequency with which patients with asthma take deep inspirations (DIs) increases during bronchoconstriction. This in vitro study investigated the effect of changing the time interval between simulated DIs on airway smooth muscle shortening. The results demonstrated that decreasing the interval between simulated DIs not only decreases shortening, which may be protective against excessive airway narrowing, but also increases the rate of re-shortening post-simulated DIs, which may contribute to the increased rate of re-narrowing post-DI observed in asthma.
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21
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Tahir BA, Marshall H, Hughes PJC, Brightling CE, Collier G, Ireland RH, Wild JM. Comparison of CT ventilation imaging and hyperpolarised gas MRI: effects of breathing manoeuvre. Phys Med Biol 2019; 64:055013. [PMID: 30673634 DOI: 10.1088/1361-6560/ab0145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Image registration of lung CT images acquired at different inflation levels has been proposed as a surrogate method to map lung 'ventilation'. Prior to clinical use, it is important to understand how this technique compares with direct ventilation imaging modalities such as hyperpolarised gas MRI. However, variations in lung inflation level have been shown to affect regional ventilation distributions. Therefore, the aim of this study was to evaluate the impact of lung inflation levels when comparing CT ventilation imaging to ventilation from 3He-MRI. Seven asthma patients underwent breath-hold CT at total lung capacity (TLC) and functional residual capacity (FRC). 3He-MRI and a same-breath 1H-MRI were acquired at FRC+1L and TLC. Percentage ventilated volumes (%VVs) were calculated for FRC+1L and TLC 3He-MRI. TLC-CT and registered FRC-CT were used to compute a surrogate ventilation map from voxel-wise intensity differences in Hounsfield unit values, which was thresholded at the 10th and 20th percentiles. For direct comparison of CT and 3He-MRI ventilation, FRC+1L and TLC 3He-MRI were registered to TLC-CT indirectly via the corresponding same-breath 1H-MRI data. For 3He-MRI and CT ventilation comparison, Dice similarity coefficients (DSCs) between the binary segmentations were computed. The median (range) of %VVs for FRC+1L and TLC 3He-MRI were 90.5 (54.9-93.6) and 91.8 (67.8-96.2), respectively (p = 0.018). For MRI versus CT ventilation comparison, statistically significant improvements in DSCs were observed for TLC 3He MRI when compared with FRC+1L, with median (range) values of 0.93 (0.86-0.93) and 0.86 (0.68-0.92), respectively (p = 0.017), for the 10-100th percentile and 0.87 (0.83-0.88) and 0.81 (0.66-0.87), respectively (p = 0.027), for the 20-100th percentile. Correlation of CT ventilation imaging and hyperpolarised gas MRI is sensitive to lung inflation level. For ventilation maps derived from CT acquired at FRC and TLC, a higher correlation with gas ventilation MRI can be achieved if the MRI is acquired at TLC.
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Affiliation(s)
- Bilal A Tahir
- POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom. Academic Unit of Clinical Oncology, University of Sheffield, Sheffield, United Kingdom. Author to whom any correspondence should be addressed
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22
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Bossé Y. The Strain on Airway Smooth Muscle During a Deep Inspiration to Total Lung Capacity. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2019; 2:0108021-1080221. [PMID: 32328568 PMCID: PMC7164505 DOI: 10.1115/1.4042309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/06/2018] [Indexed: 02/05/2023]
Abstract
The deep inspiration (DI) maneuver entices a great deal of interest because of its ability to temporarily ease the flow of air into the lungs. This salutary effect of a DI is proposed to be mediated, at least partially, by momentarily increasing the operating length of airway smooth muscle (ASM). Concerningly, this premise is largely derived from a growing body of in vitro studies investigating the effect of stretching ASM by different magnitudes on its contractility. The relevance of these in vitro findings remains uncertain, as the real range of strains ASM undergoes in vivo during a DI is somewhat elusive. In order to understand the regulation of ASM contractility by a DI and to infer on its putative contribution to the bronchodilator effect of a DI, it is imperative that in vitro studies incorporate levels of strains that are physiologically relevant. This review summarizes the methods that may be used in vivo in humans to estimate the strain experienced by ASM during a DI from functional residual capacity (FRC) to total lung capacity (TLC). The strengths and limitations of each method, as well as the potential confounders, are also discussed. A rough estimated range of ASM strains is provided for the purpose of guiding future in vitro studies that aim at quantifying the regulatory effect of DI on ASM contractility. However, it is emphasized that, owing to the many limitations and confounders, more studies will be needed to reach conclusive statements.
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Affiliation(s)
- Ynuk Bossé
- Université Laval, Faculty of Medicine, Department of Medicine, IUCPQ, M2694, Pavillon Mallet, Chemin Sainte-Foy, Québec, QC G1V 4G5, Canada e-mail:
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23
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Hallstrand TS, Leuppi JD, Joos G, Hall GL, Carlsen KH, Kaminsky DA, Coates AL, Cockcroft DW, Culver BH, Diamant Z, Gauvreau GM, Horvath I, de Jongh FHC, Laube BL, Sterk PJ, Wanger J. ERS technical standard on bronchial challenge testing: pathophysiology and methodology of indirect airway challenge testing. Eur Respir J 2018; 52:13993003.01033-2018. [PMID: 30361249 DOI: 10.1183/13993003.01033-2018] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/20/2018] [Indexed: 12/20/2022]
Abstract
Recently, this international task force reported the general considerations for bronchial challenge testing and the performance of the methacholine challenge test, a "direct" airway challenge test. Here, the task force provides an updated description of the pathophysiology and the methods to conduct indirect challenge tests. Because indirect challenge tests trigger airway narrowing through the activation of endogenous pathways that are involved in asthma, indirect challenge tests tend to be specific for asthma and reveal much about the biology of asthma, but may be less sensitive than direct tests for the detection of airway hyperresponsiveness. We provide recommendations for the conduct and interpretation of hyperpnoea challenge tests such as dry air exercise challenge and eucapnic voluntary hyperpnoea that provide a single strong stimulus for airway narrowing. This technical standard expands the recommendations to additional indirect tests such as hypertonic saline, mannitol and adenosine challenge that are incremental tests, but still retain characteristics of other indirect challenges. Assessment of airway hyperresponsiveness, with direct and indirect tests, are valuable tools to understand and to monitor airway function and to characterise the underlying asthma phenotype to guide therapy. The tests should be interpreted within the context of the clinical features of asthma.
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Affiliation(s)
- Teal S Hallstrand
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA, USA
| | - Joerg D Leuppi
- University Clinic of Medicine, Cantonal Hospital Baselland, Liestal, and Medical Faculty University of Basel, Basel, Switzerland
| | - Guy Joos
- Dept of Respiratory Medicine, University of Ghent, Ghent, Belgium
| | - Graham L Hall
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, and Centre for Child Health Research University of Western Australia, Perth, Australia
| | - Kai-Håkon Carlsen
- University of Oslo, Institute of Clinical Medicine, and Oslo University Hospital, Division of Child and Adolescent Medicine, Oslo, Norway
| | - David A Kaminsky
- Pulmonary and Critical Care, University of Vermont College of Medicine, Burlington, VT, USA
| | - Allan L Coates
- Division of Respiratory Medicine, Translational Medicine, Research Institute-Hospital for Sick Children, University of Toronto, ON, Canada
| | - Donald W Cockcroft
- Division of Respirology, Critical Care and Sleep Medicine, Royal University Hospital, Saskatoon, SK, Canada
| | - Bruce H Culver
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA, USA
| | - Zuzana Diamant
- Dept of Clinical Pharmacy and Pharmacology and QPS-Netherlands, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.,Dept of Respiratory Medicine and Allergology, Lund University, Lund, Sweden
| | - Gail M Gauvreau
- Division of Respirology, Dept of Medicine, McMaster University, Hamilton, ON, Canada
| | - Ildiko Horvath
- Dept of Pulmonology, National Korányi Institute of Pulmonology, Budapest, Hungary
| | - Frans H C de Jongh
- Dept of Pulmonary Medicine, Medisch Spectrum Twente, Enschede, The Netherlands
| | - Beth L Laube
- Division of Pediatric Pulmonology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter J Sterk
- Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Jack Wanger
- Pulmonary Function Testing and Clinical Trials Consultant, Rochester, MN, USA
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24
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Mailhot-Larouche S, Bossé Y. Interval between simulated deep inspirations on the dynamics of airway smooth muscle contraction in guinea pig bronchi. Respir Physiol Neurobiol 2018; 259:136-142. [PMID: 30217723 DOI: 10.1016/j.resp.2018.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/06/2018] [Accepted: 09/10/2018] [Indexed: 11/26/2022]
Abstract
A certain amount of time is required to achieve a maximal contraction from airway smooth muscle (ASM) and stretches of substantial magnitude, such as the ones imparted by deep inspirations (DIs), interfere with contraction. The duration of ASM contraction without interference may thus affect its shortening, its mechanical response to DIs and the overall toll it exerts on the respiratory system. In this study, the effect of changing the interval between DIs on the dynamics of ASM was examined in vitro. Isolated bronchi derived from guinea pigs were held isotonically and stimulated to both contract and relax, in a randomized order, in response to 10-5 M of methacholine and 10-6 M of isoproterenol, respectively. Interference to ASM was inflicted after 2, 5, 10 and 30 min in a randomized order, by imposing a stretch that simulated a DI. The shortening before the stretch, the stiffness before and during the stretch, the post-stretch elongation of ASM and the ensuing re-shortening were measured. These experiments were also performed in the presence of simulated tidal breathing achieved through force fluctuations. The results demonstrate that, with or without force fluctuations, increasing the interval between simulated DIs increased shortening and post-stretch elongation, but not stiffness and re-shortening. These time-dependent effects were not observed when ASM was held in the relaxed state. These findings may help understand to which extent ASM shortening and the regulatory effect of DI are affected by changing the interval between DIs. The potential consequences of these findings on airway narrowing are also discussed.
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25
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Plantier L, Beydon N, Chambellan A, Degano B, Delclaux C, Dewitte JD, Dinh-Xuan AT, Garcia G, Kauffmann C, Paris C, Perez T, Poussel M, Wuyam B, Zerah-Lancner F, Chenuel B. [Guidelines for methacholine provocation testing]. Rev Mal Respir 2018; 35:759-775. [PMID: 30097294 DOI: 10.1016/j.rmr.2018.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/15/2018] [Indexed: 12/01/2022]
Abstract
Bronchial challenge with the direct bronchoconstrictor agent methacholine is commonly used for the diagnosis of asthma. The "Lung Function" thematic group of the French Pulmonology Society (SPLF) elaborated a series of guidelines for the performance and the interpretation of methacholine challenge testing, based on French clinical guideline methodology. Specifically, guidelines are provided with regard to the choice of judgment criteria, the management of deep inspirations, and the role of methacholine bronchial challenge in the care of asthma, exercise-induced asthma, and professional asthma.
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Affiliation(s)
- L Plantier
- CEPR/Inserm UMR1100, CHRU de Tours, service de pneumologie et explorations fonctionnelles respiratoires, université François-Rabelais, 37044 Tours cedex 9, France.
| | - N Beydon
- Unité fonctionnelle d'exploration fonctionnelle respiratoire et du sommeil, AP-HP, hôpital Armand-Trousseau, 75012 Paris, France
| | - A Chambellan
- Inserm UMR1087, explorations fonctionnelles et réhabilitation respiratoire, l'institut du thorax, CHU, 44093 Nantes cedex 1, France
| | - B Degano
- Service d'explorations fonctionnelles, hôpital Jean-Minjoz, 25000 Besançon, France
| | - C Delclaux
- Inserm U1141, DHU PROTECT, service de physiologie explorations fonctionnelles pédiatriques-CPPS, AP-HP, hôpital Robert-Debré, université Paris Diderot, 75019 Paris, France
| | - J-D Dewitte
- Santé au travail-laboratoire d'étude et de recherche en sociologie, UFR médecine et sciences de la santé, université de Bretagne occidentale, 29238 Brest cedex 3, France
| | - A T Dinh-Xuan
- Service de physiologie-explorations fonctionnelles, université Paris Descartes, AP-HP, hôpital Cochin, 75014 Paris, France
| | - G Garcia
- Service de physiologie, Inserm UMR999, AP-HP, hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre cedex, France
| | - C Kauffmann
- Service d'explorations fonctionnelles respiratoires, CHU, 63000 Clermont-Ferrand, France
| | - C Paris
- EA7892, service de pathologie professionnelle, université de Lorraine, CHU de Nancy, 54500 Vandœuvre-Les-Nancy, France
| | - T Perez
- Clinique de pneumologie, centre de compétences maladies pulmonaires rares, CHRU de Lille, hôpital Albert-Calmette, 59037 Lille, France
| | - M Poussel
- Antenne médicale de prévention du dopage, EA 3450, service des examens de la fonction respiratoire et de l'aptitude à l'exercice médecine du sport, CHRU de Nancy Brabois, 54500 Vandœuvre-lès-Nancy, France
| | - B Wuyam
- Laboratoire HP2, Inserm 1042, service sport et pathologies, CHU de Grenoble, hôpital Sud, 38130 Echirolles, France
| | - F Zerah-Lancner
- Service de physiologie-explorations fonctionnelles, AP-HP, hôpital Henri-Mondor, 94000 Créteil, France
| | - B Chenuel
- Antenne médicale de prévention du dopage, EA 3450, service des examens de la fonction respiratoire et de l'aptitude à l'exercice médecine du sport, CHRU de Nancy Brabois, 54500 Vandœuvre-lès-Nancy, France
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26
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Tliba O, Panettieri RA. Paucigranulocytic asthma: Uncoupling of airway obstruction from inflammation. J Allergy Clin Immunol 2018; 143:1287-1294. [PMID: 29928921 DOI: 10.1016/j.jaci.2018.06.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 05/17/2018] [Accepted: 06/01/2018] [Indexed: 01/01/2023]
Abstract
Among patients with asthma, heterogeneity exists regarding the pattern of airway inflammation and response to treatment, prompting the necessity of recognizing specific phenotypes. Based on the analysis of inflammatory cell counts in induced sputum, asthmatic patients can be classified into 4 unique phenotypes: eosinophilic asthma, neutrophilic asthma, mixed granulocytic asthma, and paucigranulocytic asthma (PGA). PGA is an asthma phenotype with no evidence of increased numbers of eosinophils or neutrophils in sputum or blood and in which anti-inflammatory therapies are ineffective at controlling symptoms. Although underinvestigated, PGA is the most common asthma phenotype in patients with stable asthma. However, PGA is sometimes underestimated because of the exclusive reliance on induced sputum cell counts, which are variable among cohorts of studies, prompting the necessity of developing improved biomarkers. Importantly, investigators have reported that inhaled corticosteroids had a limited effect on airway inflammatory markers in patients with PGA and therefore defining PGA as a potentially "steroid-insensitive" phenotype that requires exploration of alternative therapies. PGA manifests as an uncoupling of airway obstruction from airway inflammation that can be driven by structural changes within the airways, such as airway smooth muscle tissue hypertrophy. Animal models provide evidence that processes evoking airway hyperresponsiveness and airway smooth muscle thickening occur independent from inflammation and might be a consequence of a loss of negative homeostatic processes. Collectively, further understanding of PGA with a focus on the characterization, prevalence, clinical significance, and pathobiology derived from animal studies will likely provide precision therapies that will improve PGA clinical outcomes.
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Affiliation(s)
- Omar Tliba
- Rutgers Institute for Translational Medicine & Science, Robert Wood Johnson School of Medicine, Rutgers, State University of New Jersey, New Brunswick, NJ
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine & Science, Robert Wood Johnson School of Medicine, Rutgers, State University of New Jersey, New Brunswick, NJ.
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27
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Ferreira DS, Carvalho-Pinto RM, Gregório MG, Annoni R, Teles AM, Buttignol M, Araújo-Paulino BB, Katayama EH, Oliveira BL, Del Frari HS, Cukier A, Dolhnikoff M, Stelmach R, Rabe KF, Mauad T. Airway pathology in severe asthma is related to airflow obstruction but not symptom control. Allergy 2018; 73:635-643. [PMID: 28960335 DOI: 10.1111/all.13323] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2017] [Indexed: 01/02/2023]
Abstract
BACKGROUND Patients with asthma present structural and inflammatory alterations that are believed to play a role in disease severity. However, airway remodeling and inflammation have not been extensively investigated in relation to both symptom control and airflow obstruction in severe asthmatics. We aimed to investigate several inflammatory and structural pathological features in bronchial biopsies of severe asthmatics that could be related to symptom control and airflow obstruction after standardized treatment. METHODS Fifty severe asthmatics received prednisone 40 mg/d for 2 weeks and maintenance therapy with budesonide/formoterol 400/12 μg twice daily + budesonide/formoterol 200/6 μg as needed for 12 weeks. Endobronchial biopsies were performed at the end of 12 weeks. We performed extensive immunopathological analyses of airway tissue inflammation and remodeling features in patients stratified by asthma symptom control and by airflow obstruction. RESULTS Airway tissue inflammation and remodeling were not associated with symptom control. Asthmatics with persistent airflow obstruction had greater airway smooth muscle (Asm) area with decreased periostin and transforming growth factor beta-positive cells within Asm bundles, in addition to lower numbers of chymase-positive mast cells in the submucosa compared to patients with nonpersistent obstruction. CONCLUSIONS Symptom control in severe asthmatics was not associated with airway tissue inflammation and remodeling, although persistent airflow obstruction in these patients was associated with bronchial inflammation and airway structural changes.
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Affiliation(s)
- D. S. Ferreira
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
| | - R. M. Carvalho-Pinto
- Pulmonary Division; Heart Institute (InCor); University of São Paulo Medical School; São Paulo Brazil
| | - M. G. Gregório
- Pulmonary Division; Heart Institute (InCor); University of São Paulo Medical School; São Paulo Brazil
| | - R. Annoni
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
| | - A. M. Teles
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
| | - M. Buttignol
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
| | - B. B. Araújo-Paulino
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
| | - E. H. Katayama
- University of São Paulo Medical School; São Paulo Brazil
| | - B. L. Oliveira
- University of São Paulo Medical School; São Paulo Brazil
| | | | - A. Cukier
- Pulmonary Division; Heart Institute (InCor); University of São Paulo Medical School; São Paulo Brazil
| | - M. Dolhnikoff
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
| | - R. Stelmach
- Pulmonary Division; Heart Institute (InCor); University of São Paulo Medical School; São Paulo Brazil
| | - K. F. Rabe
- LungenClinic Grosshansdorf; Grosshansdorf Germany
- Airway Research Center North in the German Center for Lung Research (DZL)
| | - T. Mauad
- Department of Pathology; University of São Paulo Medical School; São Paulo Brazil
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28
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Finucane KE, Singh B. Role of bronchodilation and pattern of breathing in increasing tidal expiratory flow with progressive induced hypercapnia in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2018; 124:91-98. [PMID: 28982946 DOI: 10.1152/japplphysiol.00752.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypercapnia (HC) in vitro relaxes airway smooth muscle; in vivo, it increases respiratory effort, tidal expiratory flows (V̇exp), and, by decreasing inspiratory duration (Ti), increases elastic recoil pressure (Pel) via lung viscoelasticity; however, its effect on airway resistance is uncertain. We examined the contributions of bronchodilation, Ti, and expiratory effort to increasing V̇exp with progressive HC in 10 subjects with chronic obstructive pulmonary disease (COPD): mean forced expiratory volume in 1 s (FEV1) 53% predicted. Lung volumes (Vl), V̇exp, esophageal pressure (Pes), Ti, and end-tidal Pco2 ([Formula: see text]) were measured during six tidal breaths followed by an inspiratory capacity (IC), breathing air, and at three levels of HC. V̇exp and V̇ with submaximal forced vital capacities breathing air (V̇sFVC) were compared. Pulmonary resistance ( Rl) was measured from the Pes-V̇ relationship. V̇exp and Pes at end-expiratory lung volume (EELV) + 0.3 tidal volume [V̇(0.3Vt) and Pes(0.3Vt), respectively], Ti, and Rl correlated with [Formula: see text] ( P < 0.001 for all) and were independent of tiotropium. [Formula: see text], Ti, and Pes(0.3Vt) predicted the increasing V̇(0.3Vt)/V̇sFVC(0.3Vt) [multiple regression analysis (MRA): P = 0.001, 0.004, and 0.025, respectively]. At [Formula: see text] ≥ 50 Torr, V̇(0.3Vt)/V̇sFVC(0.3Vt) exceeded unity in 30 of 36 measurements and was predicted by [Formula: see text] and Pes(0.3Vt) (MRA: P = 0.02 and 0.025, respectively). Rl decreased at [Formula: see text] 45 Torr ( P < 0.05) and did not change with further HC. IC and Vl(0.3Vt) did not change with HC. We conclude that in COPD HC increases V̇exp due to bronchodilation, increased Pel secondary to decreasing Ti, and increased expiratory effort, all promoting lung emptying and a stable EELV. NEW & NOTEWORTHY The response of airways to intrapulmonary hypercapnia (HC) is uncertain. In chronic obstructive pulmonary disease (COPD), progressive HC increases tidal expiratory flows by inducing bronchodilation and via an increased rate of inspiration and lung viscoelasticity, a probable increase in lung elastic recoil pressure, both changes increasing expiratory flows, promoting lung emptying and a stable end-expiratory volume. Bronchodilation with HC occurred despite optimal standard bronchodilator therapy, suggesting that in COPD further bronchodilation is possible.
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Affiliation(s)
- Kevin E Finucane
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia.,West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre , Perth, Western Australia , Australia
| | - Bhajan Singh
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia.,West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre , Perth, Western Australia , Australia.,Faculty of Science, University of Western Australia, Perth, Western Australia, Australia
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29
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d'Hooghe JNS, Ten Hacken NHT, Weersink EJM, Sterk PJ, Annema JT, Bonta PI. Emerging understanding of the mechanism of action of Bronchial Thermoplasty in asthma. Pharmacol Ther 2017; 181:101-107. [PMID: 28757156 DOI: 10.1016/j.pharmthera.2017.07.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bronchial Thermoplasty (BT) is an endoscopic treatment for moderate-to-severe asthma patients who are uncontrolled despite optimal medical therapy. Effectiveness of BT has been demonstrated in several randomized clinical trials. However, the asthma phenotype that benefits most of this treatment is unclear, partly because the mechanism of action is incompletely understood. BT was designed to reduce the amount of airway smooth muscle (ASM), but additional direct and indirect effects on airway pathophysiology are expected. This review will provide an overview of the different components of airway pathophysiology including remodeling, with the ASM as the key player. Current concepts in the understanding of BT clinical effectiveness with a focus on its impact on airway remodeling will be reviewed.
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Affiliation(s)
- J N S d'Hooghe
- Department of Respiratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - N H T Ten Hacken
- Department of Respiratory Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - E J M Weersink
- Department of Respiratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - P J Sterk
- Department of Respiratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - J T Annema
- Department of Respiratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - P I Bonta
- Department of Respiratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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30
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Thamrin C, Frey U, Kaminsky DA, Reddel HK, Seely AJE, Suki B, Sterk PJ. Systems Biology and Clinical Practice in Respiratory Medicine. The Twain Shall Meet. Am J Respir Crit Care Med 2017; 194:1053-1061. [PMID: 27556336 DOI: 10.1164/rccm.201511-2288pp] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Respiratory diseases are highly complex, being driven by host-environment interactions and manifested by inflammatory, structural, and functional abnormalities that vary over time. Traditional reductionist approaches have contributed vastly to our knowledge of biological systems in health and disease to date; however, they are insufficient to provide an understanding of the behavior of the system as a whole. In this Pulmonary Perspective, we discuss systems biology approaches, especially but not limited to the study of the lung as a complex system. Such integrative approaches take into account the large number of dynamic subunits and their interactions found in biological systems. Borrowing methods from physics and mathematics, it is possible to study the collective behavior of these systems over time and in a multidimensional manner. We first examine the physiological basis for complexity in the respiratory system and its implications for disease. We then expand on the potential applications of systems biology methods to study complex systems, within the context of diagnosis and monitoring of respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD), and critical illness. We summarize the significant advances made in recent years using systems approaches for disease phenotyping, applied to data ranging from the molecular to clinical level, obtained from large-scale asthma and COPD networks. We describe new studies using temporal complexity patterns to characterize asthma and COPD and predict exacerbations as well as predict adverse outcomes in critical care. We highlight new methods that are emerging with this approach and discuss remaining questions that merit greater attention in the field.
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Affiliation(s)
- Cindy Thamrin
- 1 Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Urs Frey
- 2 University Children's Hospital Basel, Basel, Switzerland
| | - David A Kaminsky
- 3 University of Vermont College of Medicine, Burlington, Vermont
| | - Helen K Reddel
- 1 Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew J E Seely
- 4 Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Béla Suki
- 5 Department of Biomedical Engineering, Boston University, Boston, Massachusetts; and
| | - Peter J Sterk
- 6 Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
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31
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Mailhot-Larouche S, Lortie K, Marsolais D, Flamand N, Bossé Y. An in vitro study examining the duration between deep inspirations on the rate of renarrowing. Respir Physiol Neurobiol 2017; 243:13-19. [PMID: 28487171 DOI: 10.1016/j.resp.2017.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/07/2017] [Accepted: 04/29/2017] [Indexed: 12/12/2022]
Abstract
The factors altering the bronchodilatory response to a deep inspiration (DI) in asthma are important to decipher. In this in vitro study, we investigated the effect of changing the duration between DIs on the rate of force recovery post-DI in guinea pig bronchi. The airway smooth muscle (ASM) within the main bronchi were submitted to length oscillation that simulated tidal breathing in different contractile states during 2, 5, 10 or 30min prior to a larger length excursion that simulated a DI. The contractile states of ASM were determined by adding either methacholine or isoproterenol. Irrespective of the contractile state, the duration between DIs neither affected the measured force during length oscillation nor the bronchodilator effect of DI. Contrastingly, the rate of force recovery post-DI in contracted state increased as the duration between DIs decreased. Similar results were obtained with contracted parenchymal strips. These findings suggest that changing the duration between DIs may alter the rate of ASM force recovery post-DI and thereby affect the rate of renarrowing and the duration of the respiratory relief afforded by DI.
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Affiliation(s)
- Samuel Mailhot-Larouche
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - Katherine Lortie
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - David Marsolais
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - Nicolas Flamand
- 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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32
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Kraemer R, Smith HJ, Sigrist T, Giger G, Keller R, Frey M. Diagnostic accuracy of methacholine challenge tests assessing airway hyperreactivity in asthmatic patients - a multifunctional approach. Respir Res 2016; 17:154. [PMID: 27855687 PMCID: PMC5114725 DOI: 10.1186/s12931-016-0470-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 11/04/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There are few studies comparing diagnostic accuracy of different lung function parameters evaluating dose-response characteristics of methacholine (MCH) challenge tests (MCT) as quantitative outcome of airway hyperreactivity (AHR) in asthmatic patients. The aim of this retrospectively analysis of our database (Clinic Barmelweid, Switzerland) was, to assess diagnostic accuracy of several lung function parameters quantitating AHR by dose-response characteristics. METHODS Changes in effective specific airway conductance (sGeff) as estimate of the degree of bronchial obstruction were compared with concomitantly measured forced expiratory volume in 1 s (FEV1) and forced expiratory flows at 50% forced vital capacity (FEF50). According to the GINA Guidelines the patients (n = 484) were classified into asthmatic patients (n = 337) and non-asthmatic subjects (n = 147). Whole-body plethysmography (CareFusion, Würzburg, Germany) was performed using ATS-ERS criteria, and for the MCTs a standardised computer controlled protocol with 3 consecutive cumulative provocation doses (PD1: 0.2 mg; PD2: 1.0 mg; PD3: 2.2 mg) was used. Break off criterion for the MCTs were when a decrease in FEV1 of 20% was reached or respiratory symptoms occurred. RESULTS In the assessment of AHR, whole-body plethysmography offers in addition to spirometry indices of airways conductance and thoracic lung volumes, which are incorporated in the parameter sGeff, derived from spontaneous tidal breathing. The cumulative percent dose-responses at each provocation step were at the 1st level step (0.2 mg MCH) 3.7 times, at the 2nd level step (1 mg MCH) 2.4 times, and at the 3rd level step (2.2 mg MCH) 2.0 times more pronounced for sGeff, compared to FEV1. A much better diagnostic odds ratio of sGeff (7.855) over FEV1 (6.893) and FEF50 (4.001) could be found. Moreover, the so-called dysanapsis, and changes of end-expiratory lung volume were found to be important determinants of AHR. CONCLUSIONS Applying plethysmographic tidal breathing analysis in addition to spirometry in MCTs provides relevant advantages. The absence of deep and maximal inhalations and forced expiratory manoeuvres improve the subject's cooperation and coordination, and provide sensitive and differentiated test results, improving diagnostic accuracy. Moreover, by the combined assessment, pulmonary hyperinflation and dysanapsis can be respected in the differentiation between "asthmatics" and "non-asthmatics".
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Affiliation(s)
- Richard Kraemer
- Department of Clinical Research, University of Berne, Kirchenfeldstrasse 74, CH-3005, Berne, Switzerland.
| | - Hans-Jürgen Smith
- Medical Development, Research in Respiratory Diagnostics, Berlin, Germany
| | - Thomas Sigrist
- Division of Pulmonary Medicine, Clinic Barmelweid, CH-5017, Barmelweid, Switzerland
| | - Gabi Giger
- Division of Pulmonary Medicine, Clinic Barmelweid, CH-5017, Barmelweid, Switzerland
| | - Roland Keller
- Division of Pulmonary Medicine, Clinic Barmelweid, CH-5017, Barmelweid, Switzerland
| | - Martin Frey
- Division of Pulmonary Medicine, Clinic Barmelweid, CH-5017, Barmelweid, Switzerland
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33
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Abstract
Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.
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Affiliation(s)
- P Bradding
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, UK
| | - G Arthur
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, UK
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34
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Arthur G, Bradding P. New Developments in Mast Cell Biology: Clinical Implications. Chest 2016; 150:680-93. [PMID: 27316557 DOI: 10.1016/j.chest.2016.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/26/2016] [Accepted: 06/03/2016] [Indexed: 12/12/2022] Open
Abstract
Mast cells (MCs) are present in connective tissue and at mucosal surfaces in all classes of vertebrates. In health, they contribute to tissue homeostasis, host defense, and tissue repair via multiple receptors regulating the release of a vast stockpile of proinflammatory mediators, proteases, and cytokines. However, these potentially protective cells are a double-edged sword. When there is a repeated or long-term stimulus, MC activation leads to tissue damage and dysfunction. Accordingly, MCs are implicated in the pathophysiologic aspects of numerous diseases covering all organs. Understanding the biology of MCs, their heterogeneity, mechanisms of activation, and signaling cascades may lead to the development of novel therapies for many diseases for which current treatments are lacking or are of poor efficacy. This review will focus on updates and developments in MC biology and their clinical implications, with a particular focus on their role in respiratory diseases.
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Affiliation(s)
- Greer Arthur
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, England
| | - Peter Bradding
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, England.
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35
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Ansell TK, Mitchell HW, McFawn PK, Noble PB. TNF and IL-1β exposure increases airway narrowing but does not alter the bronchodilatory response to deep inspiration in airway segments. Respirology 2016; 21:1041-8. [PMID: 27199075 DOI: 10.1111/resp.12800] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/27/2016] [Accepted: 02/15/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND OBJECTIVE While chronic inflammation of the airway wall and the failure of deep inspiration (DI) to produce bronchodilation are both common to asthma, whether pro-inflammatory cytokines modulate the airway smooth muscle response to strain during DI is unknown. The primary aim of the study was to determine how an inflammatory environment (simulated by the use of pro-inflammatory cytokines) alters the bronchodilatory response to DI. METHODS We used whole porcine bronchial segments in vitro that were cultured in medium containing tumour necrosis factor and interleukin-1β for 2 days. A custom-built servo-controlled syringe pump and pressure transducer was used to measure airway narrowing and to simulate tidal breathing with intermittent DI manoeuvres. RESULTS Culture with tumour necrosis factor and interleukin-1β increased airway narrowing to acetylcholine but did not affect the bronchodilatory response to DI. CONCLUSION The failure of DI to produce bronchodilation in patients with asthma may not necessarily involve a direct effect of pro-inflammatory cytokines on airway tissue. A relationship between inflammation and airway hyper-responsiveness is supported, however, regulated by separate disease processes than those which attenuate or abolish the bronchodilatory response to DI in patients with asthma.
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Affiliation(s)
- Thomas K Ansell
- School of Veterinary and Life Sciences, Murdoch University, Murdoch.,School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Howard W Mitchell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter K McFawn
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B Noble
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia.,Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Crawley, Western Australia, Australia
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36
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Hernandez JM, Janssen LJ. Revisiting the usefulness of thromboxane-A2 modulation in the treatment of bronchoconstriction in asthma. Can J Physiol Pharmacol 2014; 93:111-7. [PMID: 25581104 DOI: 10.1139/cjpp-2014-0364] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Airway smooth muscle (ASM) is the effector cell in the bronchoconstrictory pathway. It is believed that the bronchoconstriction present in asthma is associated with changes in the airway milieu that affect ASM excitation-contraction coupling and Ca(2+)-handling. Asthmatics also react differently to ventilatory mechanical strain. Deep inspiration (DI), which produces bronchodilation in healthy individuals, is less effective in asthmatics, and even enhances bronchoconstriction in moderate to severely affected patients. Our laboratory has previously studied the mechanotransductory pathway of airway stretch-activated contractions (Rstretch) leading to DI-induced bronchoconstriction. We demonstrated the ability of agonists acting through thromboxane A2 (TxA2) receptors to amplify airway Rstretch responses. Despite the involvement of excitatory prostanoids in bronchoconstriction, clinical trials on treatments targeting TxA2-synthase inhibition and TP-receptor antagonism have produced mixed results. Studies in Western populations produced mostly negative results, whereas studies performed in Asian populations showed mostly positive outcomes. In this review, we discuss the role of TxA2-synthase inhibition and TP-receptor antagonism in the treatment of asthmatics. We present information regarding variations in study designs and the possible role of TP-receptor gene polymorphisms in previous study outcome discrepancies. Perhaps future studies should focus on asthmatic patients with DI-induced bronchoconstriction in particular, planting the seed for the individualized treatments for asthmatics.
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Affiliation(s)
- Jeremy Mark Hernandez
- Firestone Institute for Respiratory Health, Father Sean O'Sullivan Research Centre, and Department of Medicine, McMaster University, St. Joseph's Hospital, 50 Charlton Avenue East, Hamilton, ON L8N 4A6, Canada
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Chapman DG, Pascoe CD, Lee-Gosselin A, Couture C, Seow CY, Paré PD, Salome CM, King GG, Bossé Y. Smooth Muscle in the Maintenance of Increased Airway Resistance Elicited by Methacholine in Humans. Am J Respir Crit Care Med 2014; 190:879-85. [DOI: 10.1164/rccm.201403-0502oc] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Yick CY, Zwinderman AH, Kunst PW, Grünberg K, Mauad T, Chowdhury S, Bel EH, Baas F, Lutter R, Sterk PJ. Gene expression profiling of laser microdissected airway smooth muscle tissue in asthma and atopy. Allergy 2014; 69:1233-40. [PMID: 24888725 DOI: 10.1111/all.12452] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Asthma and atopy share common characteristics including type 2 helper-T-cell-mediated inflammation. However, only asthma is associated with variable airways obstruction. The complex cellular and molecular pathways distinguishing asthma and atopy can now be captured by transcriptomic analysis (RNA-Seq). We hypothesized that the transcriptomic profile of airway smooth muscle (ASM) distinguishes atopic asthma from atopic healthy controls. First, we compared the ASM transcriptomic profiles of endobronchial biopsies between glucocorticoid-free, atopic asthma patients, and atopic and nonatopic healthy controls. Second, we investigated the association between ASM transcriptomic profiles and airway function. METHODS Twelve asthma patients and 12 control subjects (six atopic, six nonatopic) underwent bronchoscopy. RNA of laser-dissected ASM from 96 bronchial biopsy specimens was sequenced with Roche GS FLX. Gene networks were identified using Ingenuity Pathway Analysis. RNA-Seq reads were assumed to follow a negative binomial distribution. With the current sample size, the estimated false discovery rate was approximately 1%. RESULTS One hundred and seventy four ASM genes were differentially expressed between asthma patients and atopic controls, 108 between asthma patients and nonatopic controls, and 135 between atopic and nonatopic controls. A set of eight genes discriminated asthma patients from nonasthmatic controls, irrespective of atopy. Four of these genes (RPTOR, VANGL1, FAM129A, LEPREL1) were associated with airway hyper-responsiveness (P < 0.05). CONCLUSION Airway smooth muscle from asthma patients can be distinguished from that of atopic and nonatopic control subjects by a specific gene expression profile, which is associated with airway hyper-responsiveness.
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Affiliation(s)
- C. Y. Yick
- Department of Respiratory Medicine; Academic Medical Center; Amsterdam The Netherlands
| | - A. H. Zwinderman
- Department of Epidemiology and Bioinformatics; Academic Medical Center; Amsterdam The Netherlands
| | - P. W. Kunst
- Department of Respiratory Medicine; Admiraal De Ruyter Hospital; Goes The Netherlands
| | - K. Grünberg
- Department of Pathology; VU Medical Center; Amsterdam the Netherlands
| | - T. Mauad
- Department of Pathology; São Paulo University Medical School (USP); São Paulo Brazil
| | - S. Chowdhury
- Department of Experimental Immunology; Academic Medical Center; Amsterdam The Netherlands
| | - E. H. Bel
- Department of Respiratory Medicine; Academic Medical Center; Amsterdam The Netherlands
| | - F. Baas
- Department of Genome Analysis; Academic Medical Center; Amsterdam the Netherlands
| | - R. Lutter
- Department of Respiratory Medicine; Academic Medical Center; Amsterdam The Netherlands
- Department of Experimental Immunology; Academic Medical Center; Amsterdam The Netherlands
| | - P. J. Sterk
- Department of Respiratory Medicine; Academic Medical Center; Amsterdam The Netherlands
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Abstract
Mast cells (MCs) are among the first cell types associated with allergies and asthma. Studies in human asthma have identified their presence in the lung submucosa and smooth muscle and also in the airway epithelium. As our understanding of the distribution and location of these MCs in the human airway has increased, it is clear that much remains to be understood regarding the presence and subtype of these MCs in relationship to asthma phenotypes, defined both clinically and on the basis of immunologic pathways. Human MCs have traditionally been divided into two major subtypes based on the protease granule content, with tryptase representing total MCs. There is emerging evidence that in the epithelium, MCs of an altered subtype (with tryptase, chymase, and/or carboxypeptidase A3) may play a role in the pathophysiology of poorly controlled, severe, Th2-associated asthma.
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Sohal SS, Ward C, Danial W, Wood-Baker R, Walters EH. Recent advances in understanding inflammation and remodeling in the airways in chronic obstructive pulmonary disease. Expert Rev Respir Med 2014; 7:275-88. [PMID: 23734649 DOI: 10.1586/ers.13.26] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The authors have reviewed the current literature on airway inflammation and remodeling in smoking-related chronic obstructive pulmonary disease (COPD). Detailed data on airway remodeling in COPD are especially sparse and how these changes lead to decline in lung function is not well understood. Small airway fibrosis and obliteration are likely to be the main contributors to physiological airway dysfunction and occur earlier than any subsequent development of emphysema. One potential mechanism contributing to small airway fibrosis/obliteration and change in extracellular matrix is epithelial-mesenchymal transition. When associated with angiogenesis (so-called epithelial-mesenchymal transition type 3) it may well also be the link with the development of cancer, which is closely associated with COPD, predominantly in large airways. The authors have focused on our recent publications in these areas. Further investigations teasing out these mechanisms will help improve our understanding of key airway disease processes in COPD, which may have major therapeutic implications.
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Affiliation(s)
- Sukhwinder Singh Sohal
- National Health and Medical Research Council Centre of Research Excellence for Chronic Respiratory Disease, School of Medicine, University of Tasmania, 17 Liverpool Street, Private Bag 23, Hobart, Tasmania 7000, Australia
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Abstract
Expiratory flow limitation occurs when flow ceases to increase with increasing expiratory effort. The equal pressure point concept has been largely successful in providing intuitive understanding of the phenomenon, wherein maximal flows are determined by lung recoil and resistance upstream of the site where bronchial transmural pressure is zero (the EPP). Subsequent work on the fluid dynamical foundations led to the wave-speed theory of flow limitation, where flow is limited at a site when the local gas velocity is equal to speed of propagation of pressure waves. Each is a local theory; full predictions require knowledge of both density-dependent Bernoulli pressure drops and viscosity-dependent pressure losses due to dissipation. The former is dominant at mid to high lung volumes, whereas the latter is more important at low lung volumes as the flow-limiting site moves peripherally. The observation of relative effort independence of the maximal flow versus volume curves is important clinically insofar as such maneuvers, when carefully performed, offer a unique window into the mechanics of the lung itself, with little confounding effects. In particular, the important contributions of lung recoil and airways resistance can often be assessed, with implications and applications to diagnosis and management of pulmonary disease.
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Bates JHT, Irvin CG, Farré R, Hantos Z. Oscillation mechanics of the respiratory system. Compr Physiol 2013; 1:1233-72. [PMID: 23733641 DOI: 10.1002/cphy.c100058] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The mechanical impedance of the respiratory system defines the pressure profile required to drive a unit of oscillatory flow into the lungs. Impedance is a function of oscillation frequency, and is measured using the forced oscillation technique. Digital signal processing methods, most notably the Fourier transform, are used to calculate impedance from measured oscillatory pressures and flows. Impedance is a complex function of frequency, having both real and imaginary parts that vary with frequency in ways that can be used empirically to distinguish normal lung function from a variety of different pathologies. The most useful diagnostic information is gained when anatomically based mathematical models are fit to measurements of impedance. The simplest such model consists of a single flow-resistive conduit connecting to a single elastic compartment. Models of greater complexity may have two or more compartments, and provide more accurate fits to impedance measurements over a variety of different frequency ranges. The model that currently enjoys the widest application in studies of animal models of lung disease consists of a single airway serving an alveolar compartment comprising tissue with a constant-phase impedance. This model has been shown to fit very accurately to a wide range of impedance data, yet contains only four free parameters, and as such is highly parsimonious. The measurement of impedance in human patients is also now rapidly gaining acceptance, and promises to provide a more comprehensible assessment of lung function than parameters derived from conventional spirometry.
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Affiliation(s)
- Jason H T Bates
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, Vermont, USA.
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Kudo M, Ishigatsubo Y, Aoki I. Pathology of asthma. Front Microbiol 2013; 4:263. [PMID: 24032029 PMCID: PMC3768124 DOI: 10.3389/fmicb.2013.00263] [Citation(s) in RCA: 217] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 08/16/2013] [Indexed: 12/14/2022] Open
Abstract
Asthma is a serious health and socioeconomic issue all over the world, affecting more than 300 million individuals. The disease is considered as an inflammatory disease in the airway, leading to airway hyperresponsiveness, obstruction, mucus hyper-production and airway wall remodeling. The presence of airway inflammation in asthmatic patients has been found in the nineteenth century. As the information in patients with asthma increase, paradigm change in immunology and molecular biology have resulted in an extensive evaluation of inflammatory cells and mediators involved in the pathophysiology of asthma. Moreover, it is recognized that airway remodeling into detail, characterized by thickening of the airway wall, can be profound consequences on the mechanics of airway narrowing and contribute to the chronic progression of the disease. Epithelial to mesenchymal transition plays an important role in airway remodeling. These epithelial and mesenchymal cells cause persistence of the inflammatory infiltration and induce histological changes in the airway wall, increasing thickness of the basement membrane, collagen deposition and smooth muscle hypertrophy and hyperplasia. Resulting of airway inflammation, airway remodeling leads to the airway wall thickening and induces increased airway smooth muscle mass, which generate asthmatic symptoms. Asthma is classically recognized as the typical Th2 disease, with increased IgE levels and eosinophilic inflammation in the airway. Emerging Th2 cytokines modulates the airway inflammation, which induces airway remodeling. Biological agents, which have specific molecular targets for these Th2 cytokines, are available and clinical trials for asthma are ongoing. However, the relatively simple paradigm has been doubted because of the realization that strategies designed to suppress Th2 function are not effective enough for all patients in the clinical trials. In the future, it is required to understand more details for phenotypes of asthma.
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Affiliation(s)
- Makoto Kudo
- Department of Clinical Immunology and Internal medicine, Graduate School of Medicine, Yokohama City University Yokohama, Japan
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Hulme KM, Salome CM, Brown NJ, Berend N, Agus HM, Horlyck KR, King GG, Chapman DG. Deep inspiration volume and the impaired reversal of bronchoconstriction in asthma. Respir Physiol Neurobiol 2013; 189:506-12. [PMID: 23994826 DOI: 10.1016/j.resp.2013.08.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/26/2013] [Accepted: 08/21/2013] [Indexed: 01/08/2023]
Abstract
It is unclear whether the failure to reverse bronchoconstriction with deep inspiration (DI) in asthma is due to reduced maximal dilatation of the DI. We compared the effect of different DI volumes on maximal dilatation and reversal of bronchoconstriction in nine asthmatics and ten non-asthmatics. During bronchoconstriction, subjects took DI to 40%, 70% and 100% inspiratory capacity, on separate days. Maximal dilatation was measured as respiratory system resistance (Rrs) at end-inspiration and residual dilatation as Rrs at end-expiration, both expressed as percent of Rrs at end-tidal expiration prior to DI. DI volume was positively associated with maximal dilatation in non-asthmatics (ANOVA p=0.055) and asthmatics (p=0.023). DI volume was positively associated with residual dilatation in non-asthmatics (p=0.004) but not in asthmatics (p=0.53). The degree of maximal dilatation independently predicted residual dilatation in non-asthmatics but not asthmatics. These findings suggest that the failure to reverse bronchoconstriction with DI in asthma is not due to reduced maximal dilatation, but rather due to increased airway narrowing during expiration.
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Yick CY, Zwinderman AH, Kunst PW, Grünberg K, Mauad T, Fluiter K, Bel EH, Lutter R, Baas F, Sterk PJ. Glucocorticoid-induced changes in gene expression of airway smooth muscle in patients with asthma. Am J Respir Crit Care Med 2013; 187:1076-84. [PMID: 23491407 DOI: 10.1164/rccm.201210-1886oc] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
RATIONALE Glucocorticoids are the mainstay of asthma therapy. However, it is unclear whether the benefits of glucocorticoids in asthma are merely based on antiinflammatory properties. Glucocorticoids may also alter gene expression of airway smooth muscle (ASM). We hypothesized that the gene expression profile of the ASM layer in endobronchial biopsies of patients with asthma is altered by oral glucocorticoid therapy as compared with placebo. OBJECTIVES First, we investigated the change in ASM transcriptomic profile in endobronchial biopsies after 14 days of oral glucocorticoid therapy. Second, we investigated the association between changes in ASM transcriptomic profile and lung function. METHODS Twelve steroid-free patients with atopic asthma were included in this double-blind intervention study. Endobronchial biopsies were taken before and after 14 days of oral prednisolone (n = 6) or placebo (n = 6). RNA of laser-dissected ASM was sequenced (RNA-Seq) using GS FLX+ (454/Roche). Gene networks were identified by Ingenuity Pathway Analysis. RNA-Seq reads were assumed to follow a negative binomial distribution. At the current sample size the estimated false discovery rate was approximately 3%. MEASUREMENTS AND MAIN RESULTS Fifteen genes were significantly changed by 14 days of oral prednisolone. Two of these genes (FAM129A, SYNPO2) were associated with airway hyperresponsiveness (provocative concentration of methacholine causing a 20% drop in FEV1: r = -0.740, P < 0.01; r = -0.746, P < 0.01). Pathway analysis revealed three gene networks that were associated with cellular functions including cellular growth, proliferation, and development. CONCLUSIONS Oral prednisolone changes the transcriptomic profile of the ASM layer in asthma. This indicates that in parallel to antiinflammatory properties, glucocorticoids also exert effects on gene expression of ASM, which is correlated with improved airway function.
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Affiliation(s)
- Ching Yong Yick
- Department of Respiratory Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Pyrgos G, Togias A, Brown RH. Phosphodiesterase V inhibition reduces airway responsiveness, but does not improve the beneficial effect of deep inspiration. ACTA ACUST UNITED AC 2013; 86:243-51. [PMID: 23860331 DOI: 10.1159/000350451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 02/26/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Deep inspirations (DIs) can prevent (bronchoprotection; BP) and reverse (bronchodilation; BD) methacholine (Mch)-induced bronchoconstriction, but this effect is reduced or absent in people with asthma or airways hyperresponsiveness (AHR). The mechanisms of this defect are unknown. OBJECTIVE To indirectly examine the role of guanosine 3',5'-cyclic monophosphate (cGMP) by testing the hypothesis that the phosphodiesterase (PDE) V inhibitor, sildenafil, would improve DI-induced BP in individuals with AHR. METHODS Thirty-two individuals were screened and 15 met all the inclusion/exclusion criteria (7 subjects with AHR and 8 healthy subjects). A single-dose Mch challenge inducing a 20% reduction in FEV1 in the absence of DIs was first identified. Thereafter, every study participant had 4 pairs of visits, each pair testing DI-induced BP and BD against the single-dose Mch, with no drug, or pretreatment with 25, 50 and 100 mg of sildenafil, respectively, in consecutive order. RESULTS Sildenafil did not influence baseline lung function. However, in the absence of DIs, the drug caused a dose-dependent attenuation of the Mch-induced decrease in FEV1 by 17% (median value; 25th percentile: 1, 75th percentile: 16), 35% (-3, 61) and 37% (13, 79) for the 25-, 50- and 100-mg doses, respectively (p = 0.0004). No differences between the two participant groups were found. There were no effects of sildenafil on DI-induced BP or BD. CONCLUSION We infer from these results that the mechanism responsible for the defective ability of DIs to protect the airways from bronchoconstriction is unlikely to be due to dysregulation of cGMP. Of importance, a potential role for PDE V inhibition as a bronchoprotector treatment needs to be explored.
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Affiliation(s)
- George Pyrgos
- Department of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Md., USA
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Gonem S, Raj V, Wardlaw AJ, Pavord ID, Green R, Siddiqui S. Phenotyping airways disease: an A to E approach. Clin Exp Allergy 2013. [PMID: 23181785 DOI: 10.1111/j.1365-2222.2012.04008.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The airway diseases asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous conditions with overlapping pathophysiological and clinical features. It has previously been proposed that this heterogeneity may be characterized in terms of five relatively independent domains labelled from A to E, namely airway hyperresponsiveness (AHR), bronchitis, cough reflex hypersensitivity, damage to the airways and surrounding lung parenchyma, and extrapulmonary factors. Airway hyperresponsiveness occurs in both asthma and COPD, accounting for variable day to day symptoms, although the mechanisms most likely differ between the two conditions. Bronchitis, or airway inflammation, may be predominantly eosinophilic or neutrophilic, with different treatments required for each. Cough reflex hypersensitivity is thought to underlie the chronic dry cough out of proportion to other symptoms that can occur in association with airways disease. Structural changes associated with airway disease (damage) include bronchial wall thickening, airway smooth muscle hypertrophy, bronchiectasis and emphysema. Finally, a variety of extrapulmonary factors may impact upon airway disease, including rhinosinusitis, gastroesophageal reflux disease, obesity and dysfunctional breathing. This article discusses the A to E concept in detail and describes how this framework may be used to assess and treat patients with airway diseases in the clinic.
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Affiliation(s)
- S Gonem
- Department of Infection, Immunity & Inflammation, Institute for Lung Health, University of Leicester, Leicester, UK
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Gartman EJ, Dinino EK, Koo P, Roberts MB, McCool FD. Methacholine-induced airway hyper-reactivity phenotypes. J Asthma 2013; 50:629-33. [PMID: 23574335 DOI: 10.3109/02770903.2013.794237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The incorporation of airways conductance/resistance is a rare feature in clinical methacholine challenge test (MCT) protocols, and the majority of pulmonary laboratories rely solely on the spirometric parameters. The importance and interpretation of an MCT demonstrating a significant decline in specific airway conductance specific airway conductance (sGaw), but not forced expiratory volume in one second (FEV(1)), remains undefined. This study sought to elucidate the clinical and physiologic phenotypes of individuals with a ≥40% sGaw decline but <20% FEV(1) change. METHODS All subjects completed the Asthma Quality of Life Questionnaire (AQLQ), followed by standard MCT, with measurements of sGaw and an additional independent measurement of resistance and reactance by impulse oscillation system (IOS) before and after MCT. RESULTS Of 201 subjects, 47(23.4%) were in Group 1 (FEV(1) declined by ≥20%), 45(22.4%) were in Group 2 (non-significant FEV(1) drop, sGaw declined ≥40%), and 109(54.2%) were in Group 3 (no significant decline in FEV(1)/sGaw). There was a nearly identical change in all oscillometric parameters and sGaw for Groups 1 and 2 versus Group 3. There were no differences between Groups 1 and 2 in any AQLQ category, and Groups 1 and 2 were statistically different from Group 3. CONCLUSIONS Our prospective study suggests that patients with a significant sGaw decline alone during MCT are a clinically and physiologically important hyper-reactivity phenotype--whose hyper-reactivity independently was confirmed to be nearly identical to those with an FEV(1) decline. By failing to assess airways conductance/resistance, asthma may be inappropriately "ruled out" in ∼20% of the patients referred for MCT. Based on this, standardized incorporation of body plethysmography and/or IOS to MCT protocols should be considered.
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Affiliation(s)
- Eric J Gartman
- Division of Pulmonary, Critical Care, and Sleep Medicine, Warren Alpert School of Medicine of Brown University, Pawtucket, RI, USA.
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Ravensberg AJ, Slats AM, van Wetering S, Janssen K, van Wijngaarden S, de Jeu R, Rabe KF, Sterk PJ, Hiemstra PS. CD8(+) T cells characterize early smoking-related airway pathology in patients with asthma. Respir Med 2013; 107:959-66. [PMID: 23639272 DOI: 10.1016/j.rmed.2013.03.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 02/10/2013] [Accepted: 03/26/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND Smoking in asthma occurs frequently and is associated with increased symptom severity, an impaired response to corticosteroids, and accelerated lung function decline. Airway pathology in smoking asthmatics is characterized by neutrophilia and epithelial changes such as goblet cell hyperplasia and increased proliferation. Bronchial CD8(+) T cells are implicated in lung function decline in asthma and COPD. We hypothesized that smoking modifies airway inflammation in asthma by increasing the number of CD8(+) T cells at an early stage. OBJECTIVES & METHODS To study effects of smoking on airway pathology in bronchial biopsies from atopic patients with controlled intermittent or mild persistent asthma (12 smokers, 9.7 py and 11 never-smokers, 0.0 py; 20-50 yrs; FEV1 > 70% predicted; PC20MCh < 8 mg/mL, no ICS) using immunohistochemistry. RESULTS Smoking asthmatics showed higher numbers of bronchial CD8(+) T cells (55.8 vs 23.9 cells/0.1 mm(2); p = 0.001) and CD68(+) macrophages (7.5 vs 4.6 cells/0.1 mm(2), p = 0.012), and a lower CD4(+)/CD8(+) cell ratio (0.16 vs 0.40; p = 0.007) compared with non-smoking asthmatics, but no difference in neutrophils. Furthermore, the % intact epithelium was higher in smoking asthmatics (49.3 vs 23.3, p = 0.001). CONCLUSION Smoking asthmatics with a limited smoking history show a distinct pattern of airway pathology characterized by a bronchial infiltrate of CD8(+) T cells and CD68(+) macrophages, and epithelial remodelling resembling COPD-like features. This raises the hypothesis that early presence of CD8(+) T cells contributes to disease progression in smoking asthmatics.
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Affiliation(s)
- A Janneke Ravensberg
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
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Nensa F, Kotschy-Lang N, Smith HJ, Marek W, Merget R. Assessment of airway hyperresponsiveness: comparison of spirometry and body plethysmography. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 755:1-9. [PMID: 22826043 DOI: 10.1007/978-94-007-4546-9_1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
While methacholine (MCH) testing is commonly used in the clinical diagnosis of asthma, the detection of airway narrowing often relies on either spirometry or body plethysmography, however comparative studies are rare. In this study we performed MCH testing in 37 patients with variable shortness of breath at work and in 37 patients with no history of airway disease. The inclusion criteria were: no acute respiratory infection within 6 weeks, no severe diseases, normal baseline specific airway resistance (sR(aw)), normal baseline forced expiratory volume in 1 s (FEV(1)), Tiffeneau index >70%, no previous treatment with steroids within 14 days and no short acting bronchodilators within 24 h. Cumulative doses of 0.003, 0.014, 0.059, 0.239 and 0.959 mg MCH were inhaled by a dosimeter method. A FEV(1) decrease of ≥20% from baseline and a 100% increase of sR(aw) to ≥2.0 kPa/s was defined as end-of-test-criterion. Provocation doses were calculated by interpolation. Performance of lung function parameters was compared using receiver-operating-characteristic (ROC) analysis. ROC analysis resulted in an area under the ROC curve (AUC) of 0.74 for FEV(1) vs. 0.82 for sR(aw). The corresponding Youden Indices (J) were 0.46 for FEV(1) and 0.57 for sR(aw). The Youden Index of sR(aw) was higher and sensitivity and specificity (73%/84%) were rather well-balanced, in contrast to FEV(1) (54%/92%). In conclusion, in cumulative MCH challenges sR(aw) was found to be the overall most useful parameter for the detection of bronchial hyperresponsiveness. Body plethysmography yielded a balanced sensitivity-specificity ratio with higher sensitivity than spirometry, but comparable specificity.
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Affiliation(s)
- F Nensa
- Institute of the Ruhr-University, Bürkle-de-la-Camp-Platz 1, Bochum, Germany
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