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Pathak MP, Patowary P, Chattopadhyay P, Barbhuiyan PA, Islam J, Gogoi J, Wankhar W. Obesity-associated Airway Hyperresponsiveness: Mechanisms Underlying Inflammatory Markers and Possible Pharmacological Interventions. Endocr Metab Immune Disord Drug Targets 2024; 24:1053-1068. [PMID: 37957906 DOI: 10.2174/0118715303256440231028072049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 08/14/2023] [Accepted: 09/15/2023] [Indexed: 11/15/2023]
Abstract
Obesity is rapidly becoming a global health problem affecting about 13% of the world's population affecting women and children the most. Recent studies have stated that obese asthmatic subjects suffer from an increased risk of asthma, encounter severe symptoms, respond poorly to anti-asthmatic drugs, and ultimately their quality-of-life decreases. Although, the association between airway hyperresponsiveness (AHR) and obesity is a growing concern among the public due to lifestyle and environmental etiologies, however, the precise mechanism underlying this association is yet to establish. Apart from aiming at the conventional antiasthmatic targets, treatment should be directed towards ameliorating obesity pathogenesis too. Understanding the pathogenesis underlying the association between obesity and AHR is limited, however, a plethora of obesity pathologies have been reported viz., increased pro-inflammatory and decreased anti-inflammatory adipokines, depletion of ROS controller Nrf2/HO-1 axis, NLRP3 associated macrophage polarization, hypertrophy of WAT, and down-regulation of UCP1 in BAT following down-regulated AMPKα and melanocortin pathway that may be correlated with AHR. Increased waist circumference (WC) or central obesity was thought to be related to severe AHR, however, some recent reports suggest body mass index (BMI), not WC tends to exaggerate airway closure in AHR due to some unknown mechanisms. This review aims to co-relate the above-mentioned mechanisms that may explain the copious relation underlying obesity and AHR with the help of published reports. A proper understanding of these mechanisms discussed in this review will ensure an appropriate treatment plan for patients through advanced pharmacological interventions.
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Affiliation(s)
| | - Pompy Patowary
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur, India
| | | | | | - Johirul Islam
- Department of Pharmaceutical Sciences, School of Health Sciences, Assam Kaziranga University, Jorhat, India
| | - Jyotchna Gogoi
- Department of Biochemistry, Faculty of Science, Assam Down Town University, Guwahati, India
| | - Wankupar Wankhar
- Department of Dialysis, Faculty of Paramedical Science, Assam Down Town University, Guwahati, India
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2
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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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3
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Kaminsky DA, Cockcroft DW, Davis BE. Respiratory System Dynamics. Semin Respir Crit Care Med 2023; 44:526-537. [PMID: 37429331 DOI: 10.1055/s-0043-1770058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
While static mechanical forces govern resting lung volumes, dynamic forces determine tidal breathing, airflow, and changes in airflow and lung volume during normal and abnormal breathing. This section will examine the mechanisms, measurement methodology, and interpretation of the dynamic changes in airflow and lung volume that occur in health and disease. We will first examine how the total work of breathing can be described by the parameters of the equation of motion, which determine the pressure required to move air into and out of the lung. This will include a detailed description of airflow characteristics and airway resistance. Next, we will review the changes in pressure and flow that determine maximal forced inspiration and expiration, which result in the maximal flow-volume loop and the clinically important forced expired volume in 1 second. We will also assess the mechanisms and interpretation of bronchodilator responsiveness, dynamic hyperinflation, and airways hyperresponsiveness.
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Affiliation(s)
- David A Kaminsky
- Division of Pulmonary and Critical Care, Department of Medicine, University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Donald W Cockcroft
- Division of Respirology, Critical Care and Sleep Medicine, University of Saskatchewan College of Medicine, Saskatoon Saskatchewan, Canada
| | - Beth E Davis
- Division of Respirology, Critical Care and Sleep Medicine, University of Saskatchewan College of Medicine, Saskatoon Saskatchewan, Canada
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4
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Tatler AL, Philp CJ, Hill MR, Cox S, Bullock AM, Habgood A, John A, Middlewick R, Stephenson KE, Goodwin AT, Billington CK, O'Dea RD, Johnson SR, Brook BS. Differential remodeling in small and large murine airways revealed by novel whole lung airway analysis. Am J Physiol Lung Cell Mol Physiol 2023; 324:L271-L284. [PMID: 36594851 PMCID: PMC9970660 DOI: 10.1152/ajplung.00034.2022] [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: 01/28/2022] [Revised: 12/12/2022] [Accepted: 12/23/2022] [Indexed: 01/04/2023] Open
Abstract
Airway remodeling occurs in chronic asthma leading to increased airway smooth muscle (ASM) mass and extracellular matrix (ECM) deposition. Although extensively studied in murine airways, studies report only selected larger airways at one time-point meaning the spatial distribution and resolution of remodeling are poorly understood. Here we use a new method allowing comprehensive assessment of the spatial and temporal changes in ASM, ECM, and epithelium in large numbers of murine airways after allergen challenge. Using image processing to analyze 20-50 airways per mouse from a whole lung section revealed increases in ASM and ECM after allergen challenge were greater in small and large rather than intermediate airways. ASM predominantly accumulated adjacent to the basement membrane, whereas ECM was distributed across the airway wall. Epithelial hyperplasia was most marked in small and intermediate airways. After challenge, ASM changes resolved over 7 days, whereas ECM and epithelial changes persisted. The new method suggests large and small airways remodel differently, and the long-term consequences of airway inflammation may depend more on ECM and epithelial changes than ASM. The improved quantity and quality of unbiased data provided by the method reveals important spatial differences in remodeling and could set new analysis standards for murine asthma models.
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Affiliation(s)
- Amanda L Tatler
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Christopher J Philp
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Michael R Hill
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Sam Cox
- Digital Research Service, University of Nottingham, Nottingham, United Kingdom
| | - Andrew M Bullock
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Anthony Habgood
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Alison John
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Robert Middlewick
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Katherine E Stephenson
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Amanda T Goodwin
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Charlotte K Billington
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Reuben D O'Dea
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Simon R Johnson
- Centre for Respiratory Research, NIHR Biomedical Research Centre and Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Bindi S Brook
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
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5
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Donovan GM, Wang KCW, Elliot JG, James AL, Noble PB. Quantifying airway remodelling for research or clinical purposes: How should we normalize for airway size? Respirology 2023; 28:223-225. [PMID: 36691759 DOI: 10.1111/resp.14454] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/08/2023] [Indexed: 01/25/2023]
Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Kimberley C W Wang
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia.,School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - John G Elliot
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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Lutchen K. A Few Bad Airways Can Wreak Havoc: Recognizing Asthma as a Local Disorder. Am J Respir Crit Care Med 2023; 207:386-388. [PMID: 36516460 PMCID: PMC9940148 DOI: 10.1164/rccm.202212-2231ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Kenneth Lutchen
- Department of Biomedical EngineeringBoston UniversityBoston, Massachusetts
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7
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James AL, Donovan GM, Green FHY, Mauad T, Abramson MJ, Cairncross A, Noble PB, Elliot JG. Heterogeneity of Airway Smooth Muscle Remodeling in Asthma. Am J Respir Crit Care Med 2023; 207:452-460. [PMID: 36399661 DOI: 10.1164/rccm.202111-2634oc] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rationale: Ventilatory defects in asthma are heterogeneous and may represent the distribution of airway smooth muscle (ASM) remodeling. Objectives: To determine the distribution of ASM remodeling in mild-severe asthma. Methods: The ASM area was measured in nine airway levels in three bronchial pathways in cases of nonfatal (n = 30) and fatal asthma (n = 20) and compared with control cases without asthma (n = 30). Correlations of ASM area within and between bronchial pathways were calculated. Asthma cases with 12 large and 12 small airways available (n = 42) were classified on the basis of the presence or absence of ASM remodeling (more than two SD of mean ASM area of control cases, n = 86) in the large or small airway or both. Measurements and Main Results: ASM remodeling varied widely within and between cases of nonfatal asthma and was more widespread and confluent and more marked in fatal cases. There were weak correlations of ASM between levels within the same or separate bronchial pathways; however, predictable patterns of remodeling were not observed. Using mean data, 44% of all asthma cases were classified as having no ASM remodeling in either the large or small airway despite a three- to 10-fold increase in the number of airways with ASM remodeling and 81% of asthma cases having ASM remodeling in at least one large and small airway. Conclusions: ASM remodeling is related to asthma severity but is heterogeneous within and between individuals and may contribute to the heterogeneous functional defects observed in asthma. These findings support the need for patient-specific targeting of ASM remodeling.
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Affiliation(s)
- Alan L James
- West Australian Sleep Disorders Research Institute, Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,School of Medicine and Pharmacology and
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Francis H Y Green
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Thais Mauad
- Department of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil; and
| | - Michael J Abramson
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Alvenia Cairncross
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - John G Elliot
- West Australian Sleep Disorders Research Institute, Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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8
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Hsieh A, Assadinia N, Hackett TL. Airway remodeling heterogeneity in asthma and its relationship to disease outcomes. Front Physiol 2023; 14:1113100. [PMID: 36744026 PMCID: PMC9892557 DOI: 10.3389/fphys.2023.1113100] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
Asthma affects an estimated 262 million people worldwide and caused over 461,000 deaths in 2019. The disease is characterized by chronic airway inflammation, reversible bronchoconstriction, and airway remodeling. Longitudinal studies have shown that current treatments for asthma (inhaled bronchodilators and corticosteroids) can reduce the frequency of exacerbations, but do not modify disease outcomes over time. Further, longitudinal studies in children to adulthood have shown that these treatments do not improve asthma severity or fixed airflow obstruction over time. In asthma, fixed airflow obstruction is caused by remodeling of the airway wall, but such airway remodeling also significantly contributes to airway closure during bronchoconstriction in acute asthmatic episodes. The goal of the current review is to understand what is known about the heterogeneity of airway remodeling in asthma and how this contributes to the disease process. We provide an overview of the existing knowledge on airway remodeling features observed in asthma, including loss of epithelial integrity, mucous cell metaplasia, extracellular matrix remodeling in both the airways and vessels, angiogenesis, and increased smooth muscle mass. While such studies have provided extensive knowledge on different aspects of airway remodeling, they have relied on biopsy sampling or pathological assessment of lungs from fatal asthma patients, which have limitations for understanding airway heterogeneity and the entire asthma syndrome. To further understand the heterogeneity of airway remodeling in asthma, we highlight the potential of in vivo imaging tools such as computed tomography and magnetic resonance imaging. Such volumetric imaging tools provide the opportunity to assess the heterogeneity of airway remodeling within the whole lung and have led to the novel identification of heterogenous gas trapping and mucus plugging as important predictors of patient outcomes. Lastly, we summarize the current knowledge of modification of airway remodeling with available asthma therapeutics to highlight the need for future studies that use in vivo imaging tools to assess airway remodeling outcomes.
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Affiliation(s)
- Aileen Hsieh
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Najmeh Assadinia
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Tillie-Louise Hackett
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada,*Correspondence: Tillie-Louise Hackett,
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9
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Cheng F, Lu T, Wang Y, Yuan D, Wei Z, Li Y, Li J, Tang R. Expression of airway smooth muscle contractile proteins in children with acute interstitial pneumonia. Int J Exp Pathol 2022; 103:190-197. [PMID: 35527237 PMCID: PMC9482355 DOI: 10.1111/iep.12443] [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: 12/07/2021] [Revised: 04/01/2022] [Accepted: 04/04/2022] [Indexed: 12/01/2022] Open
Abstract
The purpose of the present study was to investigate the expression of α-SMA and SM22α in airway smooth muscle (ASM) of bronchioles from children younger than 14 years who died of acute interstitial pneumonia (AIP). This is based upon the hypothesis that as contractile marker proteins α-SMA and SM22α can serve as an index of the overcontractile phenotype of ASM that is seen in AIP. Lung tissue samples of children were obtained from autopsies and divided into the AIP group (55.9% male and 44.1% female, between 0.4 and 132 months old, n = 34) and the control group (60% male and 40% female, between 2 and 156 months old, n = 10). We recorded the post-mortem interval (PMI), height, clinical symptoms and abdominal fat thickness (AFT) of each case. Haematoxylin-and-eosin-stained sections were used to examine the luminal area and observe the morphological changes in the bronchioles. Immunohistochemistry and Masson's trichrome staining were used to detect the expression of contractile marker proteins and the degree of pulmonary fibrosis respectively. Compared with the control group, the luminal areas of bronchioles in the AIP group were smaller (p < .001). The expression differences in α-SMA and SM22α between the two groups were statistically significant (p = .01 and p = .02 respectively). Also, there was no significant correlation of the contractile marker proteins expression with PMI, height, clinical symptoms and AFT. The collagen deposition difference in lung between the two groups was not statistically significant (p = .224). These findings suggest that enhancement of ASM contractile function appears to be involved in the death mechanism of children with AIP, which affords more insights into the understanding of AIP.
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Affiliation(s)
- Fang Cheng
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Tao Lu
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Yicheng Wang
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Didi Yuan
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Zehong Wei
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Yongguo Li
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Jianbo Li
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
| | - Renkuan Tang
- Department of Forensic Medicine, Faculty of Basic Medical ScienceChongqing Medical UniversityChongqingChina
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10
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Wang KCW, Donovan GM, Saglani S, Mauad T, James AL, Elliot JG, Noble PB. Growth of the airway smooth muscle layer from late gestation to childhood is mediated initially by hypertrophy and subsequently hyperplasia. Respirology 2022; 27:493-500. [PMID: 35266251 PMCID: PMC9545757 DOI: 10.1111/resp.14240] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 01/11/2022] [Accepted: 02/11/2022] [Indexed: 12/18/2022]
Abstract
Background and objective The airway smooth muscle (ASM) layer thickens during development. Identifying the mechanism(s) for normal structural maturation of the ASM reveals pathways susceptible to disease processes. This study characterized thickening of the ASM layer from foetal life to childhood and elucidated the underlying mechanism in terms of hypertrophy, hyperplasia and extracellular matrix (ECM) deposition. Methods Airways from post‐mortem cases were examined from seven different age groups: 22–24 weeks gestation, 25–31 weeks gestation, term (37–41 weeks gestation), <0.5 year, 0.5–1 year, 2–5 years and 6–10 years. The ASM layer area (thickness), the number and size of ASM cells and the volume fraction of ECM were assessed by planimetry and stereology. Results From late gestation to the first year of life, normalized ASM thickness more than doubled as a result of ASM hypertrophy. Thereafter, until childhood, the ASM layer grew in proportion to airway size, which was mediated by ASM hyperplasia. Hypertrophy and hyperplasia of ASM were accompanied by a proportional change in ECM such that the broad composition of the ASM layer was constant across age groups. Conclusion These data suggest that the mechanisms of ASM growth from late gestation to childhood are temporally decoupled, with early hypertrophy and subsequent proliferation. We speculate that the developing airway is highly susceptible to ASM thickening in the first year of life and that the timing of an adverse event will determine structural phenotype. A period of rapid hypertrophic airway smooth muscle growth occurs in the first year of life, representing a critical window for disruption by disease processes and/or opportunity for clinical intervention. See relatedEditorial
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Affiliation(s)
- Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Sejal Saglani
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Thais Mauad
- Department of Pathology, University of São Paulo, São Paulo, Brazil
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, The University of Western Australia, Nedlands, Western Australia, Australia
| | - John G Elliot
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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11
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Celle A, Esteves P, Cardouat G, Beaufils F, Eyraud E, Dupin I, Maurat E, Lacomme S, Ousova O, Begueret H, Thumerel M, Marthan R, Girodet PO, Berger P, Trian T. Rhinovirus infection of bronchial epithelium induces specific bronchial smooth muscle cell migration of severe asthmatic patients. J Allergy Clin Immunol 2022; 150:104-113. [PMID: 35143808 DOI: 10.1016/j.jaci.2022.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND Patients with severe asthma show an increase in both exacerbation frequency and bronchial smooth muscle (BSM) mass. Rhinovirus (RV) infection of the bronchial epithelium (BE) is the main trigger of asthma exacerbations. Histological analysis of biopsies shows that a close connection between BE and hypertrophic BSM is a criterion for severity of asthma. OBJECTIVE We hypothesized that RV infection of BE specifically increases asthmatic BSM cell migration. METHODS Serum samples, biopsies or BSM cells were obtained from 86 patients with severe asthma and 31 non-asthmatic subjects. BE cells from non-asthmatic subjects were cultured in an air-liquid interface and exposed to RV-16. Migration of BSM cells was assessed in response to BE supernatant using chemotaxis assays. Chemokine concentrations were analyzed by transcriptomics and ELISAs. Immunocytochemistry, western blotting and flow cytometry were used to quantify CXCR3 isoform distribution. CXCR3 downstream signaling pathways were assessed by calcium imaging and western blots. RESULTS BSM cells from severe asthmatic patients specifically migrated toward RV-infected BE, whereas those from non-asthmatic subjects did not. This specific migration is driven by BE CXCL10, which was increased in vitro in response to RV infection as well as in vivo in serum from exacerbating patients with severe asthma. The mechanism is related to both decreased expression and activation of the CXCR3-B-specific isoform in severe asthmatic BSM cells. CONCLUSION We have demonstrated a novel mechanism of BSM remodeling in severe asthmatic patients following RV exacerbation. This study highlights the CXCL10/CXCR3-A axis as a potential therapeutic target in severe asthma.
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Affiliation(s)
- Alexis Celle
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Pauline Esteves
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Guillaume Cardouat
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Fabien Beaufils
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France; CHU de Bordeaux, Service d'exploration fonctionnelle respiratoire, Service de chirurgie, CIC 1401
| | - Edmée Eyraud
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Isabelle Dupin
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Elise Maurat
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Sabrina Lacomme
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France
| | - Olga Ousova
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France
| | - Hugues Begueret
- CHU de Bordeaux, Service d'exploration fonctionnelle respiratoire, Service de chirurgie, CIC 1401
| | - Matthieu Thumerel
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France; CHU de Bordeaux, Service d'exploration fonctionnelle respiratoire, Service de chirurgie, CIC 1401
| | - Roger Marthan
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France; CHU de Bordeaux, Service d'exploration fonctionnelle respiratoire, Service de chirurgie, CIC 1401
| | - Pierre-Olivier Girodet
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France; CHU de Bordeaux, Service d'exploration fonctionnelle respiratoire, Service de chirurgie, CIC 1401
| | - Patrick Berger
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France; CHU de Bordeaux, Service d'exploration fonctionnelle respiratoire, Service de chirurgie, CIC 1401
| | - Thomas Trian
- Univ-Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4-33000 Bordeaux, France; INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, U1045, CIC 1401, F-33000 Bordeaux, France.
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12
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Commentaries on Viewpoint: Small airways vs. large airways in asthma: time for a new perspective. J Appl Physiol (1985) 2021; 131:1842-1848. [PMID: 34898290 DOI: 10.1152/japplphysiol.00762.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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13
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Wang YM, Xu WJ, Xiang LL, Ding M, Zhang JJ, Lu JY, Xie BJ, Gao YD. Store-operated Calcium Entry-associated Regulatory Factor Regulates Airway Inflammation and Airway Remodeling in Asthma Mice Models. Am J Physiol Lung Cell Mol Physiol 2021; 321:L533-L544. [PMID: 34231388 DOI: 10.1152/ajplung.00079.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Store-operated calcium entry (SOCE) is involved in the pathogenesis of airway inflammation and remodeling in asthma. Store-operated calcium entry-associated regulatory factor (SARAF) can down-regulate SOCE. OBJECTIVE We sought to investigate the role of SARAF in the regulation of airway inflammation and remodeling in asthma mice models, as well as in the functional regulation of human airway smooth muscle cells (hASMCs). METHODS Balb/c mice were sensitized and challenged with ovalbumin to establish the asthma mice models. Mice were transfected with lentivirus, which expressed the SARAF gene + GFP or the negative control gene + GFP. Airway resistance was measured with the animal pulmonary function system. Airway inflammation and remodeling were evaluated via histological staining. In vitro cultured hASMCs were transfected with scrambled small interfering RNA(siRNA) or SARAF-specific siRNA respecitvely. The proliferation, migration rate, hypertrophy and SOCE activity of hASMCs were examined with cell counting kit 8, wound healing test, bright field imaging and Ca2+ fluorescence imaging, respectively. SARAF expression was measured by quantitative real-time-PCR. RESULTS Asthma mice models showed decreased SARAF mRNA expression in the lungs. SARAF overexpression attenuated airway inflammation, resistance and also remodeling. Downregulation of SARAF expression with siRNA promoted the proliferation, migration, hypertrophy and SOCE activity in hASMCs. CONCLUSIONS SARAF plays a protective role against airway inflammation and remodeling in asthma mice models by blunting SOCE; SARAF may also be a functional regulating factor of hASMCs.
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Affiliation(s)
- Yi-Min Wang
- Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, China.,Department of Allergology, Zhongnan Hospital of Wuhan University, China
| | - Wen-Juan Xu
- Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, China
| | - Lin-Li Xiang
- Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, China
| | - Mei Ding
- Department of Allergology, Zhongnan Hospital of Wuhan University, China
| | - Jin-Jin Zhang
- Department of Allergology, Zhongnan Hospital of Wuhan University, China
| | - Jing-Ya Lu
- Department of Epidemiology and Biostatistics, Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Bao-Juan Xie
- Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, China
| | - Ya-Dong Gao
- Department of Allergology, Zhongnan Hospital of Wuhan University, China
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14
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Wang KCW, James AL, Noble PB. Fetal Growth Restriction and Asthma: Is the Damage Done? Physiology (Bethesda) 2021; 36:256-266. [PMID: 34159809 DOI: 10.1152/physiol.00042.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Trajectories of airway remodeling and functional impairment in asthma are consistent with the notion that airway pathology precedes or coincides with the onset of asthma symptoms and may be present at birth. An association between intrauterine growth restriction (IUGR) and asthma development has also been established, and there is value in understanding the underlying mechanism. This review considers airway pathophysiology as a consequence of IUGR that increases susceptibility to asthma.
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Affiliation(s)
- Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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15
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Donovan GM, Wang KCW, Shamsuddin D, Mann TS, Henry PJ, Larcombe AN, Noble PB. Pharmacological ablation of the airway smooth muscle layer-Mathematical predictions of functional improvement in asthma. Physiol Rep 2021; 8:e14451. [PMID: 32533641 PMCID: PMC7292900 DOI: 10.14814/phy2.14451] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/20/2020] [Accepted: 04/25/2020] [Indexed: 12/16/2022] Open
Abstract
Airway smooth muscle (ASM) plays a major role in acute airway narrowing and reducing ASM thickness is expected to attenuate airway hyper‐responsiveness and disease burden. There are two therapeutic approaches to reduce ASM thickness: (a) a direct approach, targeting specific airways, best exemplified by bronchial thermoplasty (BT), which delivers radiofrequency energy to the airway via bronchoscope; and (b) a pharmacological approach, targeting airways more broadly. An example of the less well‐established pharmacological approach is the calcium‐channel blocker gallopamil which in a clinical trial effectively reduced ASM thickness; other agents may act similarly. In view of established anti‐proliferative properties of the macrolide antibiotic azithromycin, we examined its effects in naive mice and report a reduction in ASM thickness of 29% (p < .01). We further considered the potential functional implications of this finding, if it were to extend to humans, by way of a mathematical model of lung function in asthmatic patients which has previously been used to understand the mechanistic action of BT. Predictions show that pharmacological reduction of ASM in all airways of this magnitude would reduce ventilation heterogeneity in asthma, and produce a therapeutic benefit similar to BT. Moreover there are differences in the expected response depending on disease severity, with the pharmacological approach exceeding the benefits provided by BT in more severe disease. Findings provide further proof of concept that pharmacological targeting of ASM thickness will be beneficial and may be facilitated by azithromycin, revealing a new mode of action of an existing agent in respiratory medicine.
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Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia.,Respiratory Environmental Health, Telethon Kids Institute, The University of Western Australia, Nedlands, WA, Australia
| | - Danial Shamsuddin
- Respiratory Environmental Health, Telethon Kids Institute, The University of Western Australia, Nedlands, WA, Australia.,School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Tracy S Mann
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Peter J Henry
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Alexander N Larcombe
- Respiratory Environmental Health, Telethon Kids Institute, The University of Western Australia, Nedlands, WA, Australia.,School of Public Health, Curtin University, Bentley, WA, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
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16
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van den Bosch WB, James AL, Tiddens HAWM. Structure and function of small airways in asthma patients revisited. Eur Respir Rev 2021; 30:30/159/200186. [PMID: 33472958 DOI: 10.1183/16000617.0186-2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/27/2020] [Indexed: 12/21/2022] Open
Abstract
Small airways (<2 mm in diameter) are probably involved across almost all asthma severities and they show proportionally more structural and functional abnormalities with increasing asthma severity. The structural and functional alterations of the epithelium, extracellular matrix and airway smooth muscle in small airways of people with asthma have been described over many years using in vitro studies, animal models or imaging and modelling methods. The purpose of this review was to provide an overview of these observations and to outline several potential pathophysiological mechanisms regarding the role of small airways in asthma.
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Affiliation(s)
- Wytse B van den Bosch
- Dept of Paediatric Pulmonology and Allergology, Erasmus MC - Sophia Children's Hospital, University Medical Center Rotterdam, Rotterdam, The Netherlands.,Dept of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Alan L James
- Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Australia
| | - Harm A W M Tiddens
- Dept of Paediatric Pulmonology and Allergology, Erasmus MC - Sophia Children's Hospital, University Medical Center Rotterdam, Rotterdam, The Netherlands.,Dept of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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17
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Abstract
This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.
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Affiliation(s)
- David A Kaminsky
- University of Vermont Larner College of Medicine, Burlington, Vermont, USA
| | - David G Chapman
- University of Technology Sydney, Sydney, New South Wales, Australia
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18
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Airway remodelling with spatial correlations: Implications for asthma pathogenesis. Respir Physiol Neurobiol 2020; 279:103469. [PMID: 32473215 DOI: 10.1016/j.resp.2020.103469] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/30/2020] [Accepted: 05/21/2020] [Indexed: 12/11/2022]
Abstract
Airway remodelling is a cardinal feature of asthma in which airways undergo structural changes - in particular, increased airway smooth muscle mass and total airway wall area. Remodelling has long been thought to have functional consequences in asthma due to geometric effects that can increase airway narrowing and luminal occlusion. Prior studies have examined the distribution of remodelling between and within patients, but none have yet considered the possibility for spatial correlations in airway remodelling. That is, is remodelling clustered locally, or interrelated along proximal and distal locations of the bronchial tree? In view of recent interest regarding airway remodelling produced by mechanical stimuli, we developed a mathematical model to examine whether spatial correlations in airway remodelling could arise due to cycles of bronchoconstriction and mechanotransduction. Further, we compared modelling predictions to the spatial distribution of airway remodelling in lungs from subjects with and without asthma. Results indicate that spatial correlations in airway remodelling do exist in vivo, and cycles of bronchoconstriction and mechanotransduction are one plausible mechanism for their origin. These findings offer insights into the evolution of airway remodelling in asthma, which may inform strategies for treatment and prevention.
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19
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Ingram JL. Give Me Some Room to Breathe! Can Targeting SPHK2 Reduce Airway Smooth Muscle Thickening in Asthma? Am J Respir Cell Mol Biol 2020; 62:1-2. [PMID: 31298926 PMCID: PMC6938127 DOI: 10.1165/rcmb.2019-0240ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Jennifer L Ingram
- Department of MedicineDepartment of Surgeryand
- Department of PathologyDuke University Medical CenterDurham, North Carolina
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20
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Elliot JG, Donovan GM, Wang KCW, Green FHY, James AL, Noble PB. Fatty airways: implications for obstructive disease. Eur Respir J 2019; 54:13993003.00857-2019. [PMID: 31624112 DOI: 10.1183/13993003.00857-2019] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/05/2019] [Indexed: 11/05/2022]
Abstract
Epidemiological studies report that overweight or obese asthmatic subjects have more severe disease than those of a healthy weight. We postulated that accumulation of adipose tissue within the airway wall may occur in overweight patients and contribute to airway pathology. Our aim was to determine the relationship between adipose tissue within the airway wall and body mass index (BMI) in individuals with and without asthma.Transverse airway sections were sampled in a stratified manner from post mortem lungs of control subjects (n=15) and cases of nonfatal (n=21) and fatal (n=16) asthma. The relationship between airway adipose tissue, remodelling and inflammation was assessed. The areas of the airway wall and adipose tissue were estimated by point count and expressed as area per mm of basement membrane perimeter (Pbm). The number of eosinophils and neutrophils were expressed as area densities.BMI ranged from 15 to 45 kg·m-2 and was greater in nonfatal asthma cases (p<0.05). Adipose tissue was identified in the outer wall of large airways (Pbm >6 mm), but was rarely seen in small airways (Pbm <6 mm). Adipose tissue area correlated positively with eosinophils and neutrophils in fatal asthma (Pbm >12 mm, p<0.01), and with neutrophils in control subjects (Pbm >6 mm, p=0.04).These data show that adipose tissue is present within the airway wall and is related to BMI, wall thickness and the number of inflammatory cells. Therefore, the accumulation of airway adipose tissue in overweight individuals may contribute to airway pathophysiology.
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Affiliation(s)
- John G Elliot
- West Australian Sleep Disorders Research Institute, Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia .,School of Human Sciences, The University of Western Australia, Crawley, Australia
| | - Graham M Donovan
- Dept of Mathematics, University of Auckland, Auckland, New Zealand
| | - Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, Australia.,Telethon Kids Institute, University of Western Australia, Nedlands, Australia
| | - Francis H Y Green
- Dept of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Alan L James
- West Australian Sleep Disorders Research Institute, Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Nedlands, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Australia
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21
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Winkler T. Airway Transmural Pressures in an Airway Tree During Bronchoconstriction in Asthma. ACTA ACUST UNITED AC 2019; 2:0110051-110056. [PMID: 32328574 DOI: 10.1115/1.4042478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/20/2018] [Indexed: 11/08/2022]
Abstract
Airway transmural pressure in healthy homogeneous lungs with dilated airways is approximately equal to the difference between intraluminal and pleural pressure. However, bronchoconstriction causes airway narrowing, parenchymal distortion, dynamic hyperinflation, and the emergence of ventilation defects (VDefs) affecting transmural pressure. This study aimed to investigate the changes in transmural pressure caused by bronchoconstriction in a bronchial tree. Transmural pressures before and during bronchoconstriction were estimated using an integrative computational model of bronchoconstriction. Briefly, this model incorporates a 12-generation symmetric bronchial tree, and the Anafi and Wilson model for the individual airways of the tree. Bronchoconstriction lead to the emergence of VDefs and a relative increase in peak transmural pressures of up to 84% compared to baseline. The highest increase in peak transmural pressure occurred in a central airway outside of VDefs, and the lowest increase was 27% in an airway within VDefs illustrating the heterogeneity in peak transmural pressures within a bronchial tree. Mechanisms contributing to the increase in peak transmural pressures include increased regional ventilation and dynamic hyperinflation both leading to increased alveolar pressures compared to baseline. Pressure differences between intraluminal and alveolar pressure increased driven by the increased airway resistance and its contribution to total transmural pressure reached up to 24%. In conclusion, peak transmural pressure in lungs with VDefs during bronchoconstriction can be substantially increased compared to dilated airways in healthy homogeneous lungs and is highly heterogeneous. Further insights will depend on the experimental studies taking these conditions into account.
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Affiliation(s)
- Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114 e-mail:
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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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The anatomic substrate of irreversible airway obstruction and barotrauma in a case of hurricane-triggered fatal status asthmaticus during puerperium: Lessons from an autopsy. Respir Med Case Rep 2018; 26:136-141. [PMID: 30603604 PMCID: PMC6306954 DOI: 10.1016/j.rmcr.2018.12.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 01/27/2023] Open
Abstract
Non-fully reversible airway obstruction in fatal asthma is often seen in association with profound structural changes of the bronchial wall, termed airway remodeling. Evidence suggests that heavy precipitation events can trigger epidemics of severe asthma. We present a case of fatal asthma in a young woman with no prior near-fatal exacerbations and postulate that the patient's extensive airway remodeling and puerperal state (susceptibility factors), in combination with a massive allergen challenge during a hurricane landfall (triggering factor), played a central role in her death. The autopsy revealed diffuse obstruction of proximal and distal bronchi by mucous plugs together with transmural chronic inflammation, tissue eosinophilia, extensive goblet cell hyperplasia with MUC-5 expression and airway smooth muscle (ASM) thickening. The observed distribution of airway remodeling was heterogeneous with sparing of the lingula, which exhibited hyperinflation and expansion of perivascular spaces indicative of dissecting air. The massive stagnation of mucus and significant inter-airway structural heterogeneity created an anatomical substrate for unequal airflow distribution facilitating the development of barotrauma. Although not considered conventional risk factors for fatal asthma, we believe that in this case, the patient's puerperal state in conjunction with an extreme environmental event dispersing aeroallergens were major contributors to the development of a fatal asthma attack. Our autopsy findings suggest that effective strategies to evacuate stagnated mucus and induce relaxation of thickened ASM are crucial in the management of life-threatening asthma exacerbations.
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24
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Airway remodeling in asthma: update on mechanisms and therapeutic approaches. Curr Opin Pulm Med 2018; 24:56-62. [PMID: 29076828 DOI: 10.1097/mcp.0000000000000441] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW The term 'airway remodeling' reflects changes in the type, quantity, and nature of airway wall components and their organization. The purpose of this review is to look at recent publications on airway remodeling in asthma. RECENT FINDINGS Animal models and in-vitro studies have confirmed the involvement of airway epithelium, airway smooth muscle (ASM), and extracellular matrix components in asthma-related airway remodeling. They report influences on proliferation of ASM cells, and how their orientation or morphology, in addition to the heterogeneity of ASM mass at different levels of airways could influence their effects. Clinical benefits have been observed following reduction of ASM following bronchial thermoplasty. Asthmatic epithelial cell transcriptome alterations were found to involve metabolism and epigenetics, beyond epithelial mesenchymal trophic unit driven by injury and repair in chronic inflammation. New ways to explore airway remodeling such as imaging or endoscopic techniques have been evaluated. Finally, new data support the role of eosinophils and mast cells in remodeling and show the influence of new asthma drugs on this process. SUMMARY As recently stated by an American Thoracic Society task force, we need more research on airway remodeling, its determinants and clinical relevance, and on the effects of asthma drugs on its various components.
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25
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Lutchen KR, Paré PD, Seow CY. Hyperresponsiveness: Relating the Intact Airway to the Whole Lung. Physiology (Bethesda) 2018; 32:322-331. [PMID: 28615315 DOI: 10.1152/physiol.00008.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/10/2017] [Accepted: 05/10/2017] [Indexed: 11/22/2022] Open
Abstract
We relate changes of the airway wall to the response of the intact airway and the whole lung. We address how mechanical conditions and specific structural changes for an airway contribute to hyperresponsiveness resistant to deep inspiration. This review conveys that the origins of hyperresponsiveness do not devolve into an abnormality at single structural level but require examination of the complex interplay of all the parts.
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Affiliation(s)
- Kenneth R Lutchen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Peter D Paré
- Department of Medicine, Respiratory Division, University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation-St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; and
| | - Chun Y Seow
- Centre for Heart Lung Innovation-St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; and.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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26
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Nayak AP, Deshpande DA, Penn RB. New targets for resolution of airway remodeling in obstructive lung diseases. F1000Res 2018; 7. [PMID: 29904584 PMCID: PMC5981194 DOI: 10.12688/f1000research.14581.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/23/2018] [Indexed: 12/17/2022] Open
Abstract
Airway remodeling (AR) is a progressive pathological feature of the obstructive lung diseases, including asthma and chronic obstructive pulmonary disease (COPD). The pathology manifests itself in the form of significant, progressive, and (to date) seemingly irreversible changes to distinct respiratory structural compartments. Consequently, AR correlates with disease severity and the gradual decline in pulmonary function associated with asthma and COPD. Although current asthma/COPD drugs manage airway contraction and inflammation, none of these effectively prevent or reverse features of AR. In this review, we provide a brief overview of the features and putative mechanisms affecting AR. We further discuss recently proposed strategies with promise for deterring or treating AR.
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Affiliation(s)
- Ajay P Nayak
- Center for Translational Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, USA
| | - Deepak A Deshpande
- Center for Translational Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, USA
| | - Raymond B Penn
- Center for Translational Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, USA
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27
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Pascoe CD. Unravelling the impact of early life exposures on lung structure and function in the developmental origins of asthma. Respirology 2017; 22:1241-1242. [PMID: 28590023 DOI: 10.1111/resp.13098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 05/15/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Christopher D Pascoe
- Department of Physiology and Pathophysiology, Faculty of Medicine, University of Manitoba, Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
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Wang KCW, Morton JS, Davidge ST, Larcombe AN, James AL, Donovan GM, Noble PB. Increased heterogeneity of airway calibre in adult rats after hypoxia-induced intrauterine growth restriction. Respirology 2017; 22:1329-1335. [PMID: 28516728 DOI: 10.1111/resp.13071] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/16/2017] [Accepted: 03/23/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE Intrauterine growth restriction (IUGR) is associated with asthma development. We hypothesized that IUGR disrupts airway development leading to postnatal structural abnormalities of the airway that predispose to disease. This study therefore examined structural changes to the airway and lung in a rat model of maternal hypoxia-induced IUGR. METHODS Pregnant rats were housed under hypoxic conditions (11.5% O2 ) from gestational days (GDs) 13 to 20 (pseudoglandular-canalicular stages, i.e. period of airway development) and then returned to normoxic conditions (21% O2 ). A control group of pregnant rats was housed under normoxic conditions throughout pregnancy. Weights of male offspring were recorded at birth and 7 weeks of age (adulthood), at which point lungs were fixed for morphometry and stereology (n = 6/group), or bronchoalveolar lavage fluid (BALF) was collected for cell counts (n = 6/group). RESULTS IUGR offspring were lighter at birth compared with control, but not at 7 weeks. While there was no difference in mean airway dimensions or lung volume, there was greater anatomical variation in airway lumen area in the IUGR group. A mathematical model of the human lung was used to show that greater heterogeneity in lumen area in IUGR-affected individuals increases bronchoconstriction during simulated bronchial challenge. More macrophages were identified in the BALF of IUGR offspring. CONCLUSION The rat model demonstrates that IUGR leads to a more heterogeneous distribution of airway lumen calibre in adulthood with potential implications for bronchoconstriction in human subjects. Together with increased lung macrophages, these findings support a phenotypic shift after IUGR that may impact disease susceptibility.
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Affiliation(s)
- Kimberley C W Wang
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Jude S Morton
- Department of Obstetrics and Gynaecology, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
| | - Sandra T Davidge
- Department of Obstetrics and Gynaecology, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada.,Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Alexander N Larcombe
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.,School of Public Health, Curtin University, Perth, Western Australia, Australia
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Perth, Western Australia, Australia
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Peter B Noble
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.,School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Centre for Neonatal Research and Education, School of Paediatrics and Child Health, Perth, Western Australia, Australia
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