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Perlman CE, Knudsen L, Smith BJ. The fix is not yet in: recommendation for fixation of lungs within physiological/pathophysiological volume range in preclinical pulmonary structure-function studies. Am J Physiol Lung Cell Mol Physiol 2024; 327:L218-L231. [PMID: 38712433 DOI: 10.1152/ajplung.00341.2023] [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: 11/07/2023] [Revised: 02/14/2024] [Accepted: 04/22/2024] [Indexed: 05/08/2024] Open
Abstract
Quantitative characterization of lung structures by morphometrical or stereological analysis of histological sections is a powerful means of elucidating pulmonary structure-function relations. The overwhelming majority of studies, however, fix lungs for histology at pressures outside the physiological/pathophysiological respiratory volume range. Thus, valuable information is being lost. In this perspective article, we argue that investigators performing pulmonary histological studies should consider whether the aims of their studies would benefit from fixation at functional transpulmonary pressures, particularly those of end-inspiration and end-expiration. We survey the pressures at which lungs are typically fixed in preclinical structure-function studies, provide examples of conditions that would benefit from histological evaluation at functional lung volumes, summarize available fixation methods, discuss alternative imaging modalities, and discuss challenges to implementing the suggested approach and means of addressing those challenges. We aim to persuade investigators that modifying or complementing the traditional histological approach by fixing lungs at minimal and maximal functional volumes could enable new understanding of pulmonary structure-function relations.
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Affiliation(s)
- Carrie E Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, Colorado, United States
- Section of Pulmonary and Sleep Medicine, Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States
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2
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Paget TL, Larcombe AN, Pinniger GJ, Tsioutsias I, Schneider JP, Parkinson-Lawrence EJ, Orgeig S. Mucopolysaccharidosis (MPS IIIA) mice have increased lung compliance and airway resistance, decreased diaphragm strength, and no change in alveolar structure. Am J Physiol Lung Cell Mol Physiol 2024; 326:L713-L726. [PMID: 38469649 DOI: 10.1152/ajplung.00445.2022] [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: 01/02/2023] [Revised: 12/18/2023] [Accepted: 01/18/2024] [Indexed: 03/13/2024] Open
Abstract
Mucopolysaccharidosis type IIIA (MPS IIIA) is characterized by neurological and skeletal pathologies caused by reduced activity of the lysosomal hydrolase, sulfamidase, and the subsequent primary accumulation of undegraded heparan sulfate (HS). Respiratory pathology is considered secondary in MPS IIIA and the mechanisms are not well understood. Changes in the amount, metabolism, and function of pulmonary surfactant, the substance that regulates alveolar interfacial surface tension and modulates lung compliance and elastance, have been reported in MPS IIIA mice. Here we investigated changes in lung function in 20-wk-old control and MPS IIIA mice with a closed and open thoracic cage, diaphragm contractile properties, and potential parenchymal remodeling. MPS IIIA mice had increased compliance and airway resistance and reduced tissue damping and elastance compared with control mice. The chest wall impacted lung function as observed by an increase in airway resistance and a decrease in peripheral energy dissipation in the open compared with the closed thoracic cage state in MPS IIIA mice. Diaphragm contractile forces showed a decrease in peak twitch force, maximum specific force, and the force-frequency relationship but no change in muscle fiber cross-sectional area in MPS IIIA mice compared with control mice. Design-based stereology did not reveal any parenchymal remodeling or destruction of alveolar septa in the MPS IIIA mouse lung. In conclusion, the increased storage of HS which leads to biochemical and biophysical changes in pulmonary surfactant also affects lung and diaphragm function, but has no impact on lung or diaphragm structure at this stage of the disease.NEW & NOTEWORTHY Heparan sulfate storage in the lungs of mucopolysaccharidosis type IIIA (MPS IIIA) mice leads to changes in lung function consistent with those of an obstructive lung disease and includes an increase in lung compliance and airway resistance and a decrease in tissue elastance. In addition, diaphragm muscle contractile strength is reduced, potentially further contributing to lung function impairment. However, no changes in parenchymal lung structure were observed in mice at 20 wk of age.
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Affiliation(s)
- Tamara L Paget
- Mechanisms in Cell Biology and Diseases Research Concentration, Clinical & Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Alexander N Larcombe
- Respiratory Environmental Health, Wal-yan Respiratory Research Centre, Telethon Kids Institute, Perth, Western Australia, Australia
- Occupation, Environment & Safety, School of Population Health, Curtin University, Perth, Western Australia, Australia
| | - Gavin J Pinniger
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Irene Tsioutsias
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Jan Philipp Schneider
- Hannover Medical School, Institute of Functional and Applied Anatomy, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - Emma J Parkinson-Lawrence
- Mechanisms in Cell Biology and Diseases Research Concentration, Clinical & Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Sandra Orgeig
- Mechanisms in Cell Biology and Diseases Research Concentration, Clinical & Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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Till S, Kaminsky DA. Utilizing data from the clinical pulmonary function laboratory to teach about respiratory physiology: illustrating airway-parenchymal interdependence. ADVANCES IN PHYSIOLOGY EDUCATION 2024; 48:279-283. [PMID: 38299212 DOI: 10.1152/advan.00149.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/04/2024] [Accepted: 01/30/2024] [Indexed: 02/02/2024]
Abstract
Here we demonstrate how data from the clinical pulmonary function lab can help students learn about the principle of airway-parenchymal interdependence. We examined the relationship between airway conductance (Gaw) and lung volume (thoracic gas volume, TGV) in 48 patients: 17 healthy; 20 with emphysema, expected to have reduced airway-parenchymal interdependence; and 11 with pulmonary fibrosis, expected to have increased airway-parenchymal interdependence. Our findings support these expectations, with the slope of Gaw vs. TGV being steeper among those with pulmonary fibrosis and flatter among those with emphysema, compared to the slope of the healthy group. This type of analytic approach, using real-world patient data readily available from any pulmonary function laboratory, can be used to explore other fundamental principles of respiratory physiology.NEW & NOTEWORTHY This report demonstrates how common data obtained from the clinical pulmonary function testing laboratory can be used to illustrate important principles of respiratory physiology. Here we show how the relationship between airway conductance and lung volume across different disease states reflects intrinsic differences in airway-parenchymal interdependence.
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Affiliation(s)
- Sean Till
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, Vermont, United States
| | - David A Kaminsky
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, Vermont, United States
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Sinderholm Sposato N, Bjerså K, Gilljam M, Lannefors L, Fagevik Olsén M. Musculoskeletal aspects of respiratory function in cystic fibrosis: a cross-sectional comparative study. Eur Clin Respir J 2024; 11:2350206. [PMID: 38726022 PMCID: PMC11080665 DOI: 10.1080/20018525.2024.2350206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 04/29/2024] [Indexed: 05/12/2024] Open
Abstract
Background Respiration is an intricate interaction between visceral and musculoskeletal structures. In cystic fibrosis (CF), the airways and lungs are subject to progressive obstruction and destruction. However, knowledge about the musculoskeletal aspects of respiratory function and symptoms is still limited in this patient group. Methods In a cross-sectional comparative study, 21 adults with CF enrolled at the Gothenburg CF Centre were matched with 42 healthy controls. The two groups were examined and compared in terms of thoracic mobility, respiratory muscle strength, lung function, and musculoskeletal pain in accordance with a predefined protocol. Results Significant differences were observed between the groups in the number of tender points, thoracic excursion, forced vital capacity (FVC), and forced expiratory volume (FEV). The CF group also demonstrated a tendency toward reduced function in other measurements, although these were not statistically significant. Conclusion This cross-sectional study revealed that people with CF have reduced thoracic mobility and an increased prevalence of muscular tender points, alongside decreased lung function, compared to healthy controls. These findings stress the need for greater emphasis on the often-overlooked musculoskeletal aspects of CF care, especially as people with CF are living longer and may require more musculoskeletal health support.
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Affiliation(s)
- Niklas Sinderholm Sposato
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Kristofer Bjerså
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Family Medicine, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Region Västra Götaland, Primary Care, Närhälsan Majorna, Gothenburg, Sweden
| | - Marita Gilljam
- Department of Respiratory Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Louise Lannefors
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Physiotherapy, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Monika Fagevik Olsén
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Physiotherapy, Sahlgrenska University Hospital, Gothenburg, Sweden
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5
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McGinn EA, Mandell EW, Smith BJ, Duke JW, Bush A, Abman SH. Reply to Tepper et al.: Additional Thoughts on Intrinsic Dysanapsis. Am J Respir Crit Care Med 2024; 209:1041-1042. [PMID: 38301260 DOI: 10.1164/rccm.202312-2345le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 01/31/2024] [Indexed: 02/03/2024] Open
Affiliation(s)
- Elizabeth A McGinn
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Critical Care Medicine
| | - Erica W Mandell
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Neonatology
| | - Bradford J Smith
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
- Department of Bioengineering, Anschutz School of Medicine, University of Colorado-Denver, Aurora, Colorado
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona; and
| | - Andrew Bush
- Center for Pediatrics and Child Health, Imperial College of Medicine, London, United Kingdom
| | - Steven H Abman
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
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McGinn EA, Bye E, Gonzalez T, Sosa A, Bilodeaux J, Seedorf G, Smith BJ, Abman SH, Mandell EW. Antenatal Endotoxin Induces Dysanapsis in Experimental Bronchopulmonary Dysplasia. Am J Respir Cell Mol Biol 2024; 70:283-294. [PMID: 38207120 DOI: 10.1165/rcmb.2023-0157oc] [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: 05/02/2023] [Accepted: 01/10/2024] [Indexed: 01/13/2024] Open
Abstract
Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is characterized by impaired lung development with sustained functional abnormalities due to alterations of airways and the distal lung. Although clinical studies have shown striking associations between antenatal stress and BPD, little is known about the underlying pathogenetic mechanisms. Whether dysanapsis, the concept of discordant growth of the airways and parenchyma, contributes to late respiratory disease as a result of antenatal stress is unknown. We hypothesized that antenatal endotoxin (ETX) impairs juvenile lung function as a result of altered central airway and distal lung structure, suggesting the presence of dysanapsis in this preclinical BPD model. Fetal rats were exposed to intraamniotic ETX (10 μg) or saline solution (control) 2 days before term. We performed extensive structural and functional evaluation of the proximal airways and distal lung in 2-week-old rats. Distal lung structure was quantified by stereology. Conducting airway diameters were measured using micro-computed tomography. Lung function was assessed during invasive ventilation to quantify baseline mechanics, response to methacholine challenge, and spirometry. ETX-exposed pups exhibited distal lung simplification, decreased alveolar surface area, and decreased parenchyma-airway attachments. ETX-exposed pups exhibited decreased tracheal and second- and third-generation airway diameters. ETX increased respiratory system resistance and decreased lung compliance at baseline. Only Newtonian resistance, specific to large airways, exhibited increased methacholine reactivity in ETX-exposed pups compared with controls. ETX-exposed pups had a decreased ratio of FEV in 0.1 second to FVC and a normal FEV in 0.1 second, paralleling the clinical definition of dysanapsis. Antenatal ETX causes abnormalities of the central airways and distal lung growth, suggesting that dysanapsis contributes to abnormal lung function in juvenile rats.
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Affiliation(s)
- Elizabeth A McGinn
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Critical Care Medicine
| | - Elisa Bye
- Pediatric Heart Lung Center, Department of Pediatrics
| | | | - Alexander Sosa
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jill Bilodeaux
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | | | - Bradford J Smith
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Steven H Abman
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
| | - Erica W Mandell
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Neonatology, University of Colorado School of Medicine, Aurora, Colorado; and
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Chopra A, Judson MA, Rahman NM, Doelken P. The lung is not a balloon: the self-sealing property of the lung. THE LANCET. RESPIRATORY MEDICINE 2024; 12:190-192. [PMID: 38423702 DOI: 10.1016/s2213-2600(24)00030-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 01/31/2024] [Indexed: 03/02/2024]
Affiliation(s)
- Amit Chopra
- Department of Medicine, Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY 12208, USA.
| | - Marc A Judson
- Department of Medicine, Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY 12208, USA
| | - Najib M Rahman
- Oxford Centre for Respiratory Medicine, Oxford Respiratory Trials Unit, University of Oxford, Oxford, UK; Oxford NIHR Biomedical Research Centre, Oxford, UK
| | - Peter Doelken
- Department of Medicine, Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY 12208, USA
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8
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Shah NM, Steier J, Hart N, Kaltsakas G. Effects of non-invasive ventilation on sleep in chronic hypercapnic respiratory failure. Thorax 2024; 79:281-288. [PMID: 37979970 DOI: 10.1136/thorax-2023-220035] [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: 05/28/2023] [Accepted: 10/23/2023] [Indexed: 11/20/2023]
Abstract
Chronic respiratory disease can exacerbate the normal physiological changes in ventilation observed in healthy individuals during sleep, leading to sleep-disordered breathing, nocturnal hypoventilation, sleep disruption and chronic respiratory failure. Therefore, patients with obesity, slowly and rapidly progressive neuromuscular disease and chronic obstructive airways disease report poor sleep quality. Non-invasive ventilation (NIV) is a complex intervention used to treat sleep-disordered breathing and nocturnal hypoventilation with overnight physiological studies demonstrating improvement in sleep-disordered breathing and nocturnal hypoventilation, and clinical trials demonstrating improved outcomes for patients. However, the impact on subjective and objective sleep quality is dependent on the tools used to measure sleep quality and the patient population. As home NIV becomes more commonly used, there is a need to conduct studies focused on sleep quality, and the relationship between sleep quality and health-related quality of life, in all patient groups, in order to allow the clinician to provide clear patient-centred information.
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Affiliation(s)
- Neeraj M Shah
- Lane Fox Clinical Respiratory Physiology Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Centre for Human and Applied Physiological Sciences (CHAPS), King's College London, London, UK
| | - Joerg Steier
- Lane Fox Clinical Respiratory Physiology Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Centre for Human and Applied Physiological Sciences (CHAPS), King's College London, London, UK
| | - Nicholas Hart
- Lane Fox Clinical Respiratory Physiology Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Centre for Human and Applied Physiological Sciences (CHAPS), King's College London, London, UK
| | - Georgios Kaltsakas
- Lane Fox Clinical Respiratory Physiology Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Centre for Human and Applied Physiological Sciences (CHAPS), King's College London, London, UK
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9
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McGinn EA, Mandell EW, Smith BJ, Duke JW, Bush A, Abman SH. Dysanapsis as a Determinant of Lung Function in Development and Disease. Am J Respir Crit Care Med 2023; 208:956-963. [PMID: 37677135 PMCID: PMC10870865 DOI: 10.1164/rccm.202306-1120pp] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 09/07/2023] [Indexed: 09/09/2023] Open
Affiliation(s)
| | - Erica W. Mandell
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Neonatology
| | - Bradford J. Smith
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
- Department of Bioengineering, Anschutz School of Medicine, University of Colorado–Denver, Aurora, Colorado
| | - Joseph W. Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona; and
| | - Andrew Bush
- Center for Pediatrics and Child Health, Imperial College of Medicine, London, United Kingdom
| | - Steven H. Abman
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
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10
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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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11
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Zhang W, Wu Y, J Gunst S. Membrane adhesion junctions regulate airway smooth muscle phenotype and function. Physiol Rev 2023; 103:2321-2347. [PMID: 36796098 PMCID: PMC10243546 DOI: 10.1152/physrev.00020.2022] [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: 05/31/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
The local environment surrounding airway smooth muscle (ASM) cells has profound effects on the physiological and phenotypic properties of ASM tissues. ASM is continually subjected to the mechanical forces generated during breathing and to the constituents of its surrounding extracellular milieu. The smooth muscle cells within the airways continually modulate their properties to adapt to these changing environmental influences. Smooth muscle cells connect to the extracellular cell matrix (ECM) at membrane adhesion junctions that provide mechanical coupling between smooth muscle cells within the tissue. Membrane adhesion junctions also sense local environmental signals and transduce them to cytoplasmic and nuclear signaling pathways in the ASM cell. Adhesion junctions are composed of clusters of transmembrane integrin proteins that bind to ECM proteins outside the cell and to large multiprotein complexes in the submembranous cytoplasm. Physiological conditions and stimuli from the surrounding ECM are sensed by integrin proteins and transduced by submembranous adhesion complexes to signaling pathways to the cytoskeleton and nucleus. The transmission of information between the local environment of the cells and intracellular processes enables ASM cells to rapidly adapt their physiological properties to modulating influences in their extracellular environment: mechanical and physical forces that impinge on the cell, ECM constituents, local mediators, and metabolites. The structure and molecular organization of adhesion junction complexes and the actin cytoskeleton are dynamic and constantly changing in response to environmental influences. The ability of ASM to rapidly accommodate to the ever-changing conditions and fluctuating physical forces within its local environment is essential for its normal physiological function.
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Affiliation(s)
- Wenwu Zhang
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Yidi Wu
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Susan J Gunst
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
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12
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Toumpanakis D, Usmani OS. Small airways disease in patients with alpha-1 antitrypsin deficiency. Respir Med 2023; 211:107222. [PMID: 36965591 DOI: 10.1016/j.rmed.2023.107222] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/27/2023]
Abstract
Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder, characterized by panacinar emphysema mainly in the lower lobes, and predisposes to chronic obstructive pulmonary disease (COPD) at a younger age, especially in patients with concomitant cigarette smoking. Alpha-1 antitrypsin (a1-AT) is a serine protease inhibitor that mainly blocks neutrophil elastase and maintains protease/antiprotease balance in the lung and AATD is caused by mutations in the SERPINA1 gene that encodes a1-AT protein. PiZZ is the most common genotype associated with severe AATD, leading to reduced circulating levels of a1-AT. Besides its antiprotease function, a1-AT has anti-inflammatory and antioxidative effects and AATD results in defective innate immunity. Protease/antiprotease imbalance affects not only the lung parenchyma but also the small airways and recent studies have shown that AATD is associated with small airway dysfunction. Alterations in small airways structure with peripheral ventilation inhomogeneities may precede emphysema formation, providing a unique opportunity to detect early disease. The aim of the present review is to summarize the current evidence for the contribution of small airways disease in AATD-associated lung disease.
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Affiliation(s)
- Dimitrios Toumpanakis
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; General State Hospital for Thoracic Diseases of Athens "Sotiria", Greece.
| | - Omar S Usmani
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Herminghaus A, Kozlov AV, Szabó A, Hantos Z, Gylstorff S, Kuebart A, Aghapour M, Wissuwa B, Walles T, Walles H, Coldewey SM, Relja B. A Barrier to Defend - Models of Pulmonary Barrier to Study Acute Inflammatory Diseases. Front Immunol 2022; 13:895100. [PMID: 35874776 PMCID: PMC9300899 DOI: 10.3389/fimmu.2022.895100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 06/20/2022] [Indexed: 12/04/2022] Open
Abstract
Pulmonary diseases represent four out of ten most common causes for worldwide mortality. Thus, pulmonary infections with subsequent inflammatory responses represent a major public health concern. The pulmonary barrier is a vulnerable entry site for several stress factors, including pathogens such as viruses, and bacteria, but also environmental factors e.g. toxins, air pollutants, as well as allergens. These pathogens or pathogen-associated molecular pattern and inflammatory agents e.g. damage-associated molecular pattern cause significant disturbances in the pulmonary barrier. The physiological and biological functions, as well as the architecture and homeostatic maintenance of the pulmonary barrier are highly complex. The airway epithelium, denoting the first pulmonary barrier, encompasses cells releasing a plethora of chemokines and cytokines, and is further covered with a mucus layer containing antimicrobial peptides, which are responsible for the pathogen clearance. Submucosal antigen-presenting cells and neutrophilic granulocytes are also involved in the defense mechanisms and counterregulation of pulmonary infections, and thus may directly affect the pulmonary barrier function. The detailed understanding of the pulmonary barrier including its architecture and functions is crucial for the diagnosis, prognosis, and therapeutic treatment strategies of pulmonary diseases. Thus, considering multiple side effects and limited efficacy of current therapeutic treatment strategies in patients with inflammatory diseases make experimental in vitro and in vivo models necessary to improving clinical therapy options. This review describes existing models for studyying the pulmonary barrier function under acute inflammatory conditions, which are meant to improve the translational approaches for outcome predictions, patient monitoring, and treatment decision-making.
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Affiliation(s)
- Anna Herminghaus
- Department of Anaesthesiology, University of Duesseldorf, Duesseldorf, Germany
| | - Andrey V. Kozlov
- L Boltzmann Institute for Traumatology in Cooperation with AUVA and Austrian Cluster for Tissue Regeneration, Vienna, Austria
- Department of Human Pathology , IM Sechenov Moscow State Medical University, Moscow, Russia
| | - Andrea Szabó
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Zoltán Hantos
- Department of Anaesthesiology and Intensive Therapy, Semmelweis University, Budapest, Hungary
| | - Severin Gylstorff
- Experimental Radiology, Department of Radiology and Nuclear Medicine, Otto-von-Guericke University, Magdeburg, Germany
- Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| | - Anne Kuebart
- Department of Anaesthesiology, University of Duesseldorf, Duesseldorf, Germany
| | - Mahyar Aghapour
- Experimental Radiology, Department of Radiology and Nuclear Medicine, Otto-von-Guericke University, Magdeburg, Germany
| | - Bianka Wissuwa
- Department of Anaesthesiology and Intensive Care Medicine, Septomics Research Centre, Centre for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Thorsten Walles
- Department of Thoracic Surgery, Magdeburg University Medicine, Magdeburg, Germany
| | - Heike Walles
- Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
- Core Facility Tissue Engineering, Otto-von-Guericke-University, Magdeburg, Germany
| | - Sina M. Coldewey
- Department of Anaesthesiology and Intensive Care Medicine, Septomics Research Centre, Centre for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Borna Relja
- Experimental Radiology, Department of Radiology and Nuclear Medicine, Otto-von-Guericke University, Magdeburg, Germany
- Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
- *Correspondence: Borna Relja,
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Machado LMQ, Serra DS, Neves TG, Cavalcante FSÁ, Ceccatto VM, Leal‐Cardoso JH, Zin WA, Moreira‐Gomes MD. Pulmonary impairment in type 2 diabetic rats and its improvement by exercise. Acta Physiol (Oxf) 2022; 234:e13708. [PMID: 34185958 DOI: 10.1111/apha.13708] [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: 01/06/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 01/24/2023]
Abstract
AIM We aimed to evaluate whether the streptozotocin-induced diabetic model can generate lung functional, histological and biochemical impairments and whether moderate exercise can prevent these changes. METHODS Wistar rats were assigned to control (CTRL), exercise (EXE), diabetic (D) and diabetic with exercise (D+EXE) groups. We used the n5-STZ model of diabetes mellitus triggered by a single injection of streptozotocin (STZ, 120 mg/kg b.w., i.p.) in newborn rats on their 5th day of life. EXE and D+EXE rats were trained by running on a motorized treadmill, 5 days a week for 9 weeks. Blood glucose, body weight, food intake, exercise capacity, lung mechanics, morphology, and antioxidant enzymatic activity were analysed. RESULTS On the 14th week of life, diabetic rats exhibited a significant impairment in post-prandial glycaemia, glucose tolerance, body weight, food intake, lung function (tissue viscance, elastance, Newtonian resistance and hysteresis), morphological parameters, redox balance and exercise capacity. Physical training completely prevented the diabetes-induced alterations, except for those on fasting blood glucose, which nevertheless remained stable. CONCLUSIONS Mild diabetes in n5-STZ-treated rats jeopardized pulmonary mechanics, morphology and redox balance, which confirms the occurrence of diabetes-induced pneumopathy. Moreover, moderate exercise completely prevented all diabetes-induced respiratory alterations.
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Affiliation(s)
- Liz Maria Queiroz Machado
- Electrophysiology Laboratory Superior Institute of Biomedical SciencesState University of Ceará Fortaleza Brazil
| | - Daniel Silveira Serra
- Laboratory of Biophysics of Respiration Science and Technology Center State University of Ceará Ceará Brazil
| | - Thayanne Gomes Neves
- Electrophysiology Laboratory Superior Institute of Biomedical SciencesState University of Ceará Fortaleza Brazil
| | | | - Vânia Marilande Ceccatto
- Gene Expression Laboratory Superior Institute of Biomedical SciencesState University of Ceará Fortaleza Brazil
| | - Jose Henrique Leal‐Cardoso
- Electrophysiology Laboratory Superior Institute of Biomedical SciencesState University of Ceará Fortaleza Brazil
| | - Walter Araujo Zin
- Laboratory of Respiration Physiology Carlos Chagas Filho Institute of BiophysicsUniversidade Federal do Rio de Janeiro Rio de Janeiro Brazil
| | - Maria Diana Moreira‐Gomes
- Electrophysiology Laboratory Superior Institute of Biomedical SciencesState University of Ceará Fortaleza Brazil
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15
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Abstract
Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized that it can also induce local tissue biologic responses, such as inflammation, local immune dysfunction, and damage of the alveolar-capillary barrier, with potential loss of lung fluid clearance, increased lung protein permeability, and susceptibility to infection, factors that can initiate or exaggerate lung injury. Mechanical ventilation of a heterogeneously aerated lung (e.g., in the presence of atelectatic lung tissue) involves biomechanical processes that may precipitate further lung damage: concentration of mechanical forces, propagation of gas-liquid interfaces, and remote overdistension. Knowledge of such pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should guide optimal clinical management.
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16
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Ikezoe K, Hackett TL, Peterson S, Prins D, Hague CJ, Murphy D, LeDoux S, Chu F, Xu F, Cooper JD, Tanabe N, Ryerson CJ, Paré PD, Coxson HO, Colby TV, Hogg JC, Vasilescu DM. Small Airway Reduction and Fibrosis is an Early Pathologic Feature of Idiopathic Pulmonary Fibrosis. Am J Respir Crit Care Med 2021; 204:1048-1059. [PMID: 34343057 DOI: 10.1164/rccm.202103-0585oc] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE To improve disease outcomes in idiopathic pulmonary fibrosis (IPF) it is essential to understand its early pathophysiology so that it can be targeted therapeutically. OBJECTIVES Perform three-dimensional (3D) assessment of the IPF lung micro-structure using stereology and multi-resolution computed tomography (CT) imaging. METHODS Explanted lungs from IPF patients (n=8) and donor controls (n=8) were inflated with air and frozen. CT scans were used to assess large airways. Unbiased, systematic uniform random (SUR) samples (n=8/lung) were scanned with microCT for stereological assessment of small airways (number, airway wall and lumen area) and parenchymal fibrosis (volume fraction of tissue, alveolar surface area, and septal wall thickness). RESULTS The total number of airways on clinical CT was greater in IPF lungs than control lungs (p<0.01), due to an increase in the wall (p<0.05) and lumen area (p<0.05) resulting in more visible airways with a lumen larger than 2 mm. In IPF tissue samples without microscopic fibrosis, assessed by the volume fraction of tissue using microCT, there was a reduction in the number of the terminal (p<0.01) and transitional (p<0.001) bronchioles, and an increase in terminal bronchiole wall area (p<0.001) compared to control lungs. In IPF tissue samples with microscopic parenchymal fibrosis, terminal bronchioles had increased airway wall thickness (p<0.05), and dilated airway lumens (p<0.001) leading to honeycomb cyst formations. CONCLUSION This study has important implications for the current thinking on how the lung tissue is remodeled in IPF, and highlights small airways as a potential target to modify IPF outcomes.
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Affiliation(s)
- Kohei Ikezoe
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Tillie-Louise Hackett
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | | | - Dante Prins
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Cameron J Hague
- The University of British Columbia Department of Radiology, 478400, Vancouver, British Columbia, Canada
| | - Darra Murphy
- The University of British Columbia Department of Radiology, 478400, Vancouver, British Columbia, Canada
| | - Stacey LeDoux
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Fanny Chu
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Feng Xu
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Pathology and Lab Medicine, Vancouver, British Columbia, Canada
| | - Joel D Cooper
- University of Pennsylvania, 6572, Thoracic surgery, Philadelphia, Pennsylvania, United States
| | - Naoya Tanabe
- Kyoto University Graduate School of Medicine Department of Respiratory Medicine, 215651, Kyoto, Japan
| | - Christopher J Ryerson
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Medicine, Vancouver, British Columbia, Canada
| | - Peter D Paré
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Harvey O Coxson
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Thomas V Colby
- Mayo Clinic Department of Laboratory Medicine and Pathology, 195112, Rochester, Minnesota, United States
| | - James C Hogg
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada
| | - Dragoş M Vasilescu
- The University of British Columbia Centre for Heart Lung Innovation, 539747, Vancouver, British Columbia, Canada;
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17
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18
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Fayon M, Beaufils F. The lower respiratory airway wall in children in health and disease. ERJ Open Res 2021; 7:00874-2020. [PMID: 34322550 PMCID: PMC8311136 DOI: 10.1183/23120541.00874-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 03/24/2021] [Indexed: 02/06/2023] Open
Abstract
Alone or in association with other lung or thorax component disorders, the airway wall (AWW) remains one of the most frequently involved elements in paediatric lung diseases. A myriad of AWW disorders will present with similar symptomatology. It is thus important for the clinician to reappraise the normal development and structure of the AWW to better understand the underlying disease patterns. We herein provide an overview of the structure of the AWW and a description of its development from the fetal period to adulthood. We also detail the most common AWW changes observed in several acute and chronic respiratory disorders as well as after cigarette smoke or chronic pollution exposure. We then describe the relationship between the AWW structure and lung function. In addition, we present the different ways of investigating the AWW structure, from biopsies and histological analyses to the most recent noninvasive airway (AW) imaging techniques. Understanding the pathophysiological processes involved in an individual patient will lead to the judicious choice of nonspecific or specific personalised treatments, in order to prevent irreversible AW damage.
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Affiliation(s)
- Michael Fayon
- Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux Imaging Center, Bordeaux, France
- CHU de Bordeaux, Département de Pédiatrie, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France
- INSERM, Centre d'Investigation Clinique (CIC1401), Bordeaux, France
| | - Fabien Beaufils
- Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux Imaging Center, Bordeaux, France
- CHU de Bordeaux, Département de Pédiatrie, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France
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19
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Garbuzova-Davis S, Shell R, Mustafa H, Hailu S, Willing AE, Sanberg PR, Borlongan CV. Advancing Stem Cell Therapy for Repair of Damaged Lung Microvasculature in Amyotrophic Lateral Sclerosis. Cell Transplant 2021; 29:963689720913494. [PMID: 32207340 PMCID: PMC7444221 DOI: 10.1177/0963689720913494] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease of motor neuron
degeneration in the brain and spinal cord. Progressive paralysis of
the diaphragm and other respiratory muscles leading to respiratory
dysfunction and failure is the most common cause of death in ALS
patients. Respiratory impairment has also been shown in animal models
of ALS. Vascular pathology is another recently recognized hallmark of
ALS pathogenesis. Central nervous system (CNS) capillary damage is a
shared disease element in ALS rodent models and ALS patients.
Microvascular impairment outside of the CNS, such as in the lungs, may
occur in ALS, triggering lung damage and affecting breathing function.
Stem cell therapy is a promising treatment for ALS. However, this
therapeutic strategy has primarily targeted rescue of degenerated
motor neurons. We showed functional benefits from intravenous delivery
of human bone marrow (hBM) stem cells on restoration of capillary
integrity in the CNS of an superoxide dismutase 1 (SOD1) mouse model
of ALS. Due to the widespread distribution of transplanted cells via
this route, administered cells may enter the lungs and effectively
restore microvasculature in this respiratory organ. Here, we provided
preliminary evidence of the potential role of microvasculature
dysfunction in prompting lung damage and treatment approaches for
repair of respiratory function in ALS. Our initial studies showed
proof-of-principle that microvascular damage in ALS mice results in
lung petechiae at the late stage of disease and that systemic
transplantation of mainly hBM-derived endothelial progenitor cells
shows potential to promote lung restoration via re-established
vascular integrity. Our new understanding of previously underexplored
lung competence in this disease may facilitate therapy targeting
restoration of respiratory function in ALS.
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Affiliation(s)
- Svitlana Garbuzova-Davis
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Robert Shell
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Hilmi Mustafa
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Surafuale Hailu
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Alison E Willing
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Paul R Sanberg
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Cesario V Borlongan
- Center of Excellence for Aging & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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20
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Dhakal S, Loube J, Misplon JA, Lo CY, Creisher PS, Mulka KR, Deshpande S, Mitzner W, Klein SL, Epstein SL. Effect of an Adenovirus-Vectored Universal Influenza Virus Vaccine on Pulmonary Pathophysiology in a Mouse Model. J Virol 2021; 95:e02359-20. [PMID: 33627390 PMCID: PMC8104105 DOI: 10.1128/jvi.02359-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/17/2021] [Indexed: 11/20/2022] Open
Abstract
Current influenza vaccines, live attenuated or inactivated, do not protect against antigenically novel influenza A viruses (IAVs) of pandemic potential, which has driven interest in the development of universal influenza vaccines. Universal influenza vaccine candidates targeting highly conserved antigens of IAV nucleoprotein (NP) are promising as vaccines that induce T cell immunity, but concerns have been raised about the safety of inducing robust CD8 T cell responses in the lungs. Using a mouse model, we systematically evaluated effects of recombinant adenovirus vectors (rAd) expressing IAV NP (A/NP-rAd) or influenza B virus (IBV) NP (B/NP-rAd) on pulmonary inflammation and function after vaccination and following live IAV challenge. After A/NP-rAd or B/NP-rAd vaccination, female mice exhibited robust systemic and pulmonary vaccine-specific B cell and T cell responses and experienced no morbidity (e.g., body mass loss). Both in vivo pulmonary function testing and lung histopathology scoring revealed minimal adverse effects of intranasal rAd vaccination compared with unvaccinated mice. After IAV challenge, A/NP-rAd-vaccinated mice experienced significantly less morbidity, had lower pulmonary virus titers, and developed less pulmonary inflammation than unvaccinated or B/NP-rAd-vaccinated mice. Based on analysis of pulmonary physiology using detailed testing not previously applied to the question of T cell damage, mice protected by vaccination also had better lung function than controls. Results provide evidence that, in this model, adenoviral universal influenza vaccine does not damage pulmonary tissue. In addition, adaptive immunity, in particular, T cell immunity in the lungs, does not cause damage when restimulated but instead mitigates pulmonary damage following IAV infection.IMPORTANCE Respiratory viruses can emerge and spread rapidly before vaccines are available. It would be a tremendous advance to use vaccines that protect against whole categories of viruses, such as universal influenza vaccines, without the need to predict which virus will emerge. The nucleoprotein (NP) of influenza virus provides a target conserved among strains and is a dominant T cell target. In animals, vaccination to NP generates powerful T cell immunity and long-lasting protection against diverse influenza strains. Concerns have been raised, but not evaluated experimentally, that potent local T cell responses might damage the lungs. We analyzed lung function in detail in the setting of such a vaccination. Despite CD8 T cell responses in the lungs, lungs were not damaged and functioned normally after vaccination alone and were protected upon subsequent infection. This precedent provides important support for vaccines based on T cell-mediated protection, currently being considered for both influenza and SARS-CoV-2 vaccines.
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Affiliation(s)
- Santosh Dhakal
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jeffrey Loube
- Department of Environmental Health and Engineering, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Julia A Misplon
- Division of Cellular and Gene Therapies, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Chia-Yun Lo
- Division of Cellular and Gene Therapies, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Patrick S Creisher
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Kathleen R Mulka
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Sharvari Deshpande
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Wayne Mitzner
- Department of Environmental Health and Engineering, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Sabra L Klein
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Suzanne L Epstein
- Division of Cellular and Gene Therapies, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
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21
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Kizhakke Puliyakote AS, Holverda S, Sá RC, Arai TJ, Theilmann RJ, Botros L, Bogaard HJ, Prisk GK, Hopkins SR. Prone positioning redistributes gravitational stress in the lung in normal conditions and in simulations of oedema. Exp Physiol 2020; 107:771-782. [PMID: 33347661 DOI: 10.1113/ep089037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/03/2020] [Indexed: 02/01/2023]
Abstract
NEW FINDINGS What is the central question of this study? How does the interaction between posture and gravity affect the stresses on the lung, particularly in highly inflated gravitationally non-dependent regions, which are potentially vulnerable to increased mechanical stress and injury? What is the main finding and its importance? Changes in stress attributable to gravity are not well characterized between postures. Using a new metric of gravitational stress, we show that regions of the lung near maximal inflation have the greatest gravitational stresses while supine, but not while prone. In simulations of increased lung weight consistent with severe pulmonary oedema, the prone lung has lower gravitational stress in vulnerable, non-dependent regions, potentially protecting them from overinflation and injury. ABSTRACT Prone posture changes the gravitational vector, and potentially the stress induced by tissue deformation, because a larger lung volume is gravitationally dependent when supine, but non-dependent when prone. To evaluate this, 10 normal subjects (six male and four female; age, means ± SD = 27 ± 6 years; height, 171 ± 9 cm; weight, 69 ± 13 kg; forced expiratory volume in the first second/forced expiratory volume as a percentage of predicted, 93 ± 6%) were imaged at functional residual capacity, supine and prone, using magnetic resonance imaging, to quantify regional lung density. We defined regional gravitational stress as the cumulative weight, per unit area, of the column of lung tissue below each point. Gravitational stress was compared between regions of differing inflation to evaluate differences between highly stretched, and thus potentially vulnerable, regions and less stretched lung. Using reference density values for normal lungs at total lung capacity (0.10 ± 0.03 g/ml), regions were classified as highly inflated (density < 0.13 g/ml, i.e., close to total lung capacity), intermediate (0.13 ≤ density < 0.16 g/ml) or normally inflated (density ≥ 0.16 g/ml). Gravitational stress differed between inflation categories while supine (-1.6 ± 0.3 cmH2 O highly inflated; -1.4 ± 0.3 cmH2 O intermediate; -1.1 ± 0.1 cmH2 O normally inflated; P = 0.05) but not while prone (-1.4 ± 0.2 cmH2 O highly inflated; -1.3 ± 0.2 cmH2 O intermediate; -1.3 ± 0.1 cmH2 O normally inflated; P = 0.39), and increased more with height from dependent lung while supine (-0.24 ± 0.02 cmH2 O/cm supine; -0.18 ± 0.04 cmH2 O/cm prone; P = 0.05). In simulated severe pulmonary oedema, the gradient in gravitational stress increased in both postures (all P < 0.0001), was greater in the supine posture than when prone (-0.57 ± 0.21 cmH2 O/cm supine; -0.34 ± 0.16 cmH2 O/cm prone; P = 0.0004) and was similar to the gradient calculated from supine computed tomography images in a patient with acute respiratory distress syndrome (-0.51 cmH2 O/cm). The non-dependent lung has greater gravitational stress while supine and might be protected while prone, particularly in the presence of oedema.
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Affiliation(s)
- Abhilash S Kizhakke Puliyakote
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA.,The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA
| | - Sebastiaan Holverda
- The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA.,Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Rui C Sá
- The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA.,Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Tatsuya J Arai
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA.,The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA
| | - Rebecca J Theilmann
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA.,The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA
| | - Liza Botros
- Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Harm J Bogaard
- Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - G Kim Prisk
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA.,The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA.,Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Susan R Hopkins
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA.,The Pulmonary Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA.,Department of Medicine, University of California, San Diego, La Jolla, CA, USA
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22
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Pellegrini M, Gudmundsson M, Bencze R, Segelsjö M, Freden F, Rylander C, Hedenstierna G, Larsson AS, Perchiazzi G. Expiratory Resistances Prevent Expiratory Diaphragm Contraction, Flow Limitation, and Lung Collapse. Am J Respir Crit Care Med 2020; 201:1218-1229. [PMID: 32150440 DOI: 10.1164/rccm.201909-1690oc] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale: Tidal expiratory flow limitation (tidal-EFL) is not completely avoidable by applying positive end-expiratory pressure and may cause respiratory and hemodynamic complications in ventilated patients with lungs prone to collapse. During spontaneous breathing, expiratory diaphragmatic contraction counteracts tidal-EFL. We hypothesized that during both spontaneous breathing and controlled mechanical ventilation, external expiratory resistances reduce tidal-EFL.Objectives: To assess whether external expiratory resistances 1) affect expiratory diaphragmatic contraction during spontaneous breathing, 2) reduce expiratory flow and make lung compartments more homogeneous with more similar expiratory time constants, and 3) reduce tidal atelectasis, preventing hyperinflation.Methods: Three positive end-expiratory pressure levels and four external expiratory resistances were tested in 10 pigs after lung lavage. We analyzed expiratory diaphragmatic electric activity and respiratory mechanics. On the basis of computed tomography scans, four lung compartments-not inflated (atelectasis), poorly inflated, normally inflated, and hyperinflated-were defined.Measurements and Main Results: Consequently to additional external expiratory resistances, and mainly in lungs prone to collapse (at low positive end-expiratory pressure), 1) the expiratory transdiaphragmatic pressure decreased during spontaneous breathing by >10%, 2) expiratory flow was reduced and the expiratory time constants became more homogeneous, and 3) the amount of atelectasis at end-expiration decreased from 24% to 16% during spontaneous breathing and from 32% to 18% during controlled mechanical ventilation, without increasing hyperinflation.Conclusions: The expiratory modulation induced by external expiratory resistances preserves the positive effects of the expiratory brake while minimizing expiratory diaphragmatic contraction. External expiratory resistances optimize lung mechanics and limit tidal-EFL and tidal atelectasis, without increasing hyperinflation.
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Affiliation(s)
- Mariangela Pellegrini
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Magni Gudmundsson
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Reka Bencze
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Monica Segelsjö
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden; and
| | - Filip Freden
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Christian Rylander
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Göran Hedenstierna
- Department of Medical Sciences, Hedenstierna Laboratory, Uppsala University, Uppsala, Sweden
| | - Anders S Larsson
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Gaetano Perchiazzi
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
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23
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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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24
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Nieman GF, Gatto LA, Andrews P, Satalin J, Camporota L, Daxon B, Blair SJ, Al-Khalisy H, Madden M, Kollisch-Singule M, Aiash H, Habashi NM. Prevention and treatment of acute lung injury with time-controlled adaptive ventilation: physiologically informed modification of airway pressure release ventilation. Ann Intensive Care 2020; 10:3. [PMID: 31907704 PMCID: PMC6944723 DOI: 10.1186/s13613-019-0619-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/23/2019] [Indexed: 12/16/2022] Open
Abstract
Mortality in acute respiratory distress syndrome (ARDS) remains unacceptably high at approximately 39%. One of the only treatments is supportive: mechanical ventilation. However, improperly set mechanical ventilation can further increase the risk of death in patients with ARDS. Recent studies suggest that ventilation-induced lung injury (VILI) is caused by exaggerated regional lung strain, particularly in areas of alveolar instability subject to tidal recruitment/derecruitment and stress-multiplication. Thus, it is reasonable to expect that if a ventilation strategy can maintain stable lung inflation and homogeneity, regional dynamic strain would be reduced and VILI attenuated. A time-controlled adaptive ventilation (TCAV) method was developed to minimize dynamic alveolar strain by adjusting the delivered breath according to the mechanical characteristics of the lung. The goal of this review is to describe how the TCAV method impacts pathophysiology and protects lungs with, or at high risk of, acute lung injury. We present work from our group and others that identifies novel mechanisms of VILI in the alveolar microenvironment and demonstrates that the TCAV method can reduce VILI in translational animal ARDS models and mortality in surgical/trauma patients. Our TCAV method utilizes the airway pressure release ventilation (APRV) mode and is based on opening and collapsing time constants, which reflect the viscoelastic properties of the terminal airspaces. Time-controlled adaptive ventilation uses inspiratory and expiratory time to (1) gradually “nudge” alveoli and alveolar ducts open with an extended inspiratory duration and (2) prevent alveolar collapse using a brief (sub-second) expiratory duration that does not allow time for alveolar collapse. The new paradigm in TCAV is configuring each breath guided by the previous one, which achieves real-time titration of ventilator settings and minimizes instability induced tissue damage. This novel methodology changes the current approach to mechanical ventilation, from arbitrary to personalized and adaptive. The outcome of this approach is an open and stable lung with reduced regional strain and greater lung protection.
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Affiliation(s)
- Gary F Nieman
- Dept of Surgery, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA
| | - Louis A Gatto
- Dept of Surgery, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA
| | - Penny Andrews
- Multi-trauma Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, 22 South Greene Street, Baltimore, MD, USA
| | - Joshua Satalin
- Dept of Surgery, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA.
| | - Luigi Camporota
- Department of Critical Care, Guy's and St, Thomas' NHS Foundation Trust, Westminster Bridge Rd, London, SE1 7EH, UK
| | - Benjamin Daxon
- Dept of Anesthesiology and Perioperative Medicine, Mayo Clinic, 200 1st St SW, Rochester, MN, 55905, USA
| | - Sarah J Blair
- Dept of Surgery, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA
| | - Hassan Al-Khalisy
- Dept of Surgery, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA
| | - Maria Madden
- Multi-trauma Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, 22 South Greene Street, Baltimore, MD, USA
| | | | - Hani Aiash
- Dept of Surgery, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA.,Department of Clinical Perfusion, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA
| | - Nader M Habashi
- Multi-trauma Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, 22 South Greene Street, Baltimore, MD, USA
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25
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Milne S, Huvanandana J, Nguyen C, Duncan JM, Chapman DG, Tonga KO, Zimmermann SC, Slattery A, King GG, Thamrin C. Time-based pulmonary features from electrical impedance tomography demonstrate ventilation heterogeneity in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2019; 127:1441-1452. [PMID: 31556831 DOI: 10.1152/japplphysiol.00304.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary electrical impedance tomography (EIT) is a functional imaging technique that allows real-time monitoring of ventilation distribution. Ventilation heterogeneity (VH) is a characteristic feature of chronic obstructive pulmonary disease (COPD) and has previously been quantified using features derived from tidal variations in the amplitude of the EIT signal. However, VH may be better described by time-based metrics, the measurement of which is made possible by the high temporal resolution of EIT. We aimed 1) to quantify VH using novel time-based EIT metrics and 2) to determine the physiological relevance of these metrics by exploring their relationships with complex lung mechanics measured by the forced oscillation technique (FOT). We performed FOT, spirometry, and tidal-breathing EIT measurements in 11 healthy controls and 9 volunteers with COPD. Through offline signal processing, we derived 3 features from the impedance-time (Z-t) curve for each image pixel: 1) tE, mean expiratory time; 2) PHASE, mean time difference between pixel and global Z-t curves; and 3) AMP, mean amplitude of Z-t curve tidal variation. Distribution was quantified by the coefficient of variation (CV) and the heterogeneity index (HI). Both CV and HI of the tE and PHASE features were significantly increased in COPD compared with controls, and both related to spirometry and FOT resistance and reactance measurements. In contrast, distribution of the AMP feature showed no relationships with lung mechanics. These novel time-based EIT metrics of VH reflect complex lung mechanics in COPD and have the potential to allow real-time visualization of pulmonary physiology in spontaneously breathing subjects.NEW & NOTEWORTHY Pulmonary electrical impedance tomography (EIT) is a real-time imaging technique capable of monitoring ventilation with exquisite temporal resolution. We report novel, time-based EIT measurements that not only demonstrate ventilation heterogeneity in chronic obstructive pulmonary disease (COPD), but also reflect oscillatory lung mechanics. These EIT measurements are noninvasive, radiation-free, easy to obtain, and provide real-time visualization of the complex pathophysiology of COPD.
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Affiliation(s)
- Stephen Milne
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Central Clinical School, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St. Leonards, New South Wales, Australia.,Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jacqueline Huvanandana
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Chinh Nguyen
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Joseph M Duncan
- Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St. Leonards, New South Wales, Australia
| | - David G Chapman
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Translational Airways Group, School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales, Australia
| | - Katrina O Tonga
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine, the University of New South Wales, Kensington, New South Wales, Australia
| | - Sabine C Zimmermann
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St. Leonards, New South Wales, Australia
| | - Alexander Slattery
- Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St. Leonards, New South Wales, Australia
| | - Gregory G King
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St. Leonards, New South Wales, Australia.,Centre of Excellence in Severe Asthma, New Lambton, New South Wales, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Central Clinical School, University of Sydney, Sydney, New South Wales, Australia
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26
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Rühl N, Lopez-Rodriguez E, Albert K, Smith BJ, Weaver TE, Ochs M, Knudsen L. Surfactant Protein B Deficiency Induced High Surface Tension: Relationship between Alveolar Micromechanics, Alveolar Fluid Properties and Alveolar Epithelial Cell Injury. Int J Mol Sci 2019; 20:ijms20174243. [PMID: 31480246 PMCID: PMC6747270 DOI: 10.3390/ijms20174243] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/24/2019] [Accepted: 08/26/2019] [Indexed: 11/16/2022] Open
Abstract
High surface tension at the alveolar air-liquid interface is a typical feature of acute and chronic lung injury. However, the manner in which high surface tension contributes to lung injury is not well understood. This study investigated the relationship between abnormal alveolar micromechanics, alveolar epithelial injury, intra-alveolar fluid properties and remodeling in the conditional surfactant protein B (SP-B) knockout mouse model. Measurements of pulmonary mechanics, broncho-alveolar lavage fluid (BAL), and design-based stereology were performed as a function of time of SP-B deficiency. After one day of SP-B deficiency the volume of alveolar fluid V(alvfluid,par) as well as BAL protein and albumin levels were normal while the surface area of injured alveolar epithelium S(AEinjure,sep) was significantly increased. Alveoli and alveolar surface area could be recruited by increasing the air inflation pressure. Quasi-static pressure-volume loops were characterized by an increased hysteresis while the inspiratory capacity was reduced. After 3 days, an increase in V(alvfluid,par) as well as BAL protein and albumin levels were linked with a failure of both alveolar recruitment and airway pressure-dependent redistribution of alveolar fluid. Over time, V(alvfluid,par) increased exponentially with S(AEinjure,sep). In conclusion, high surface tension induces alveolar epithelial injury prior to edema formation. After passing a threshold, epithelial injury results in vascular leakage and exponential accumulation of alveolar fluid critically hampering alveolar recruitability.
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Affiliation(s)
- Nina Rühl
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
- Biomedical Research in Endstage and Obstructive Lung Diseases (BREATH), Member of the German Center for Lung Research (DLZ), Hannover 30625, Germany
- REBIRTH, Cluster of Excellence, Hannover 30625, Germany
- Institute of Vegetative Anatomy, Charite, Berlin 10117, Germany
| | - Karolin Albert
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver, Denver, CO 80045, USA
| | - Timothy E Weaver
- Division of Pulmonary Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45221, USA
| | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
- Biomedical Research in Endstage and Obstructive Lung Diseases (BREATH), Member of the German Center for Lung Research (DLZ), Hannover 30625, Germany
- REBIRTH, Cluster of Excellence, Hannover 30625, Germany
- Institute of Vegetative Anatomy, Charite, Berlin 10117, Germany
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany.
- Biomedical Research in Endstage and Obstructive Lung Diseases (BREATH), Member of the German Center for Lung Research (DLZ), Hannover 30625, Germany.
- REBIRTH, Cluster of Excellence, Hannover 30625, Germany.
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27
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Paratracheal Paraseptal Emphysema and Expiratory Central Airway Collapse in Smokers. Ann Am Thorac Soc 2019; 15:479-484. [PMID: 29298081 DOI: 10.1513/annalsats.201709-713oc] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RATIONALE Expiratory central airway collapse is associated with respiratory morbidity independent of underlying lung disease. However, not all smokers develop expiratory central airway collapse, and the etiology of expiratory central airway collapse in adult smokers is unclear. Paraseptal emphysema in the paratracheal location, by untethering airway walls, may predispose smokers to developing expiratory central airway collapse. OBJECTIVES To evaluate whether paratracheal paraseptal emphysema is associated with expiratory central airway collapse. METHODS We analyzed paired inspiratory and expiratory computed tomography scans from participants enrolled in a multicenter study (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) of smokers aged 45 to 80 years. Expiratory central airway collapse was defined as greater than or equal to 50% reduction in cross-sectional area of the trachea during expiration. In a nested case-control design, participants with and without expiratory central airway collapse were included in a 1:2 fashion, and inspiratory scans were further analyzed using the Fleischner Society criteria for presence of centrilobular emphysema, paraseptal emphysema, airway wall thickening, and paratracheal paraseptal emphysema (maximal diameter ≥ 0.5 cm). RESULTS A total of 1,320 patients were included, 440 with and 880 without expiratory central airway collapse. Those with expiratory central airway collapse were older, had higher body mass index, and were less likely to be men or current smokers. Paratracheal paraseptal emphysema was more frequent in those with expiratory central airway collapse than control subjects (16.6 vs. 11.8%; P = 0.016), and after adjustment for age, race, sex, body mass index, smoking pack-years, and forced expiratory volume in 1 second, paratracheal paraseptal emphysema was independently associated with expiratory central airway collapse (adjusted odds ratio, 1.53; 95% confidence interval, 1.18-1.98; P = 0.001). Furthermore, increasing size of paratracheal paraseptal emphysema (maximal diameter of at least 1 cm and 1.5 cm) was associated with greater odds of expiratory central airway collapse (adjusted odds ratio, 1.63; 95% confidence interval, 1.18-2.25; P = 0.003 and 1.77; 95% confidence interval, 1.19-2.64; P = 0.005, respectively). CONCLUSIONS Paraseptal emphysema adjacent to the trachea is associated with expiratory central airway collapse. The identification of this risk factor on inspiratory scans should prompt further evaluation for expiratory central airway collapse. Clinical trial registered with ClinicalTrials.gov (NCT 00608764).
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28
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Tanabe N, Sato S, Oguma T, Shima H, Sato A, Muro S, Hirai T. Associations of airway tree to lung volume ratio on computed tomography with lung function and symptoms in chronic obstructive pulmonary disease. Respir Res 2019; 20:77. [PMID: 30999912 PMCID: PMC6471860 DOI: 10.1186/s12931-019-1047-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 04/08/2019] [Indexed: 01/06/2023] Open
Abstract
Background Decreased airway lumen size and increased lung volume are major structural changes in chronic obstructive pulmonary disease (COPD). However, even though the outer wall of the airways is connected with lung parenchyma and the mechanical properties of the parenchyma affect the behaviour of the airways, little is known about the interactions between airway and lung sizes on lung function and symptoms. The present study examined these effects by establishing a novel computed tomography (CT) index, namely, airway volume percent (AWV%), which was defined as a percentage ratio of the airway tree to lung volume. Methods Inspiratory chest CT, pulmonary function, and COPD Assessment Tests (CAT) were analysed in 147 stable males with COPD. The whole airway tree was automatically segmented, and the percentage ratio of the airway tree volume in the right upper and middle-lower lobes to right lung volume was calculated as the AWV% for right lung. Low attenuation volume % (LAV%), total airway count (TAC), luminal area (Ai), and wall area percent (WA%) were also measured. Results AWV% decreased as the Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric grade increased (p < 0.0001). AWV% was lower in symptomatic (CAT score ≥ 10) subjects than in non-symptomatic subjects (p = 0.036). AWV% was more closely correlated with forced expiratory volume in 1 s (FEV1) and ratio of residual volume to total lung capacity (RV/TLC) than Ai, Ai to lung volume ratio, and volume of either the lung or the airway tree. Multivariate analyses showed that lower AWV% was associated with lower FEV1 and higher RV/TLC, independent of LAV%, WA%, and TAC. Conclusions A disproportionally small airway tree with a relatively large lung could lead to airflow obstruction and gas trapping in COPD. AWV% is an easily measured CT biomarker that may elucidate the clinical impacts of the airway-lung interaction in COPD. Electronic supplementary material The online version of this article (10.1186/s12931-019-1047-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Naoya Tanabe
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
| | - Susumu Sato
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Tsuyoshi Oguma
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hiroshi Shima
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Atsuyasu Sato
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Shigeo Muro
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Toyohiro Hirai
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
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29
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Ito JT, Lourenço JD, Righetti RF, Tibério IFLC, Prado CM, Lopes FDTQS. Extracellular Matrix Component Remodeling in Respiratory Diseases: What Has Been Found in Clinical and Experimental Studies? Cells 2019; 8:E342. [PMID: 30979017 PMCID: PMC6523091 DOI: 10.3390/cells8040342] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/03/2019] [Accepted: 04/09/2019] [Indexed: 01/09/2023] Open
Abstract
Changes in extracellular matrix (ECM) components in the lungs are associated with the progression of respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory distress syndrome (ARDS). Experimental and clinical studies have revealed that structural changes in ECM components occur under chronic inflammatory conditions, and these changes are associated with impaired lung function. In bronchial asthma, elastic and collagen fiber remodeling, mostly in the airway walls, is associated with an increase in mucus secretion, leading to airway hyperreactivity. In COPD, changes in collagen subtypes I and III and elastin, interfere with the mechanical properties of the lungs, and are believed to play a pivotal role in decreased lung elasticity, during emphysema progression. In ARDS, interstitial edema is often accompanied by excessive deposition of fibronectin and collagen subtypes I and III, which can lead to respiratory failure in the intensive care unit. This review uses experimental models and human studies to describe how inflammatory conditions and ECM remodeling contribute to the loss of lung function in these respiratory diseases.
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Affiliation(s)
- Juliana T Ito
- Department of Clinical Medicine, Laboratory of Experimental Therapeutics/LIM-20, School of Medicine of University of Sao Paulo, Sao Paulo 01246-903, Brazil.
| | - Juliana D Lourenço
- Department of Clinical Medicine, Laboratory of Experimental Therapeutics/LIM-20, School of Medicine of University of Sao Paulo, Sao Paulo 01246-903, Brazil.
| | - Renato F Righetti
- Department of Clinical Medicine, Laboratory of Experimental Therapeutics/LIM-20, School of Medicine of University of Sao Paulo, Sao Paulo 01246-903, Brazil.
- Rehabilitation service, Sírio-Libanês Hospital, Sao Paulo 01308-050, Brazil.
| | - Iolanda F L C Tibério
- Department of Clinical Medicine, Laboratory of Experimental Therapeutics/LIM-20, School of Medicine of University of Sao Paulo, Sao Paulo 01246-903, Brazil.
| | - Carla M Prado
- Department of Bioscience, Laboratory of Studies in Pulmonary Inflammation, Federal University of Sao Paulo, Santos 11015-020, Brazil.
| | - Fernanda D T Q S Lopes
- Department of Clinical Medicine, Laboratory of Experimental Therapeutics/LIM-20, School of Medicine of University of Sao Paulo, Sao Paulo 01246-903, Brazil.
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30
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Affiliation(s)
- Olivier Ranunkel
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Firat Güder
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Hari Arora
- College of Engineering, Swansea University, Swansea SA1 8EN, United Kingdom
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31
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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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32
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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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33
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Donovan GM, Elliot JG, Boser SR, Green FHY, James AL, Noble PB. Patient-specific targeted bronchial thermoplasty: predictions of improved outcomes with structure-guided treatment. J Appl Physiol (1985) 2019; 126:599-606. [PMID: 30676870 DOI: 10.1152/japplphysiol.00951.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bronchial thermoplasty is a recent treatment for asthma in which ablative thermal energy is delivered to specific large airways according to clinical guidelines. Therefore, current practice is effectively "blind," as it is not informed by patient-specific data. The present study seeks to establish whether a patient-specific approach based on structural or functional patient data can improve outcomes and/or reduce the number of procedures required for clinical efficacy. We employed a combination of extensive human lung specimens and novel computational methods to predict bronchial thermoplasty outcomes guided by structural or functional data compared with current clinical practice. Response to bronchial thermoplasty was determined from changes in airway responses to strong bronchoconstrictor simulations and flow heterogeneity after one or three simulated thermoplasty procedures. Structure-guided treatment showed significant improvement over current unguided clinical practice, with a single session of structure-guided treatment producing improvements comparable with three sessions of unguided treatment. In comparison, function-guided treatment did not produce a significant improvement over current practice. Structure-guided targeting of bronchial thermoplasty is a promising avenue for improving therapy and reinforces the need for advanced imaging technologies. The functional imaging-guided approach is predicted to be less effective presently, and we make recommendations on how this approach could be improved. NEW & NOTEWORTHY Bronchial thermoplasty is a recent treatment for asthma in which thermal energy is delivered via bronchoscope to specific airways in an effort to directly target airway smooth muscle. Current practice involves the treatment of a standard set of airways, unguided by patient-specific data. We consider the potential for guided treatments, either by functional or structural data from the lung, and show that treatment guided by structural data has the potential to improve clinical practice.
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Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland , Auckland , New Zealand
| | - John G Elliot
- West Australian Sleep Disorders Research Institute, Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia
| | | | - Francis H Y Green
- Cumming School of Medicine, University of Calgary , Calgary, Alberta , Canada
| | - Alan L James
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, School of Medicine and Pharmacology, University of Western Australia , Australia
| | - Peter B Noble
- School of Human Sciences, University of Western Australia , Crawley, Western Australia , Australia
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34
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Osorio-Valencia JS, Wongviriyawong C, Winkler T, Kelly VJ, Harris RS, Venegas JG. Elevation in lung volume and preventing catastrophic airway closure in asthmatics during bronchoconstriction. PLoS One 2018; 13:e0208337. [PMID: 30566496 PMCID: PMC6300269 DOI: 10.1371/journal.pone.0208337] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/15/2018] [Indexed: 01/17/2023] Open
Abstract
Background Asthma exacerbations cause lung hyperinflation, elevation in load to inspiratory muscles, and decreased breathing capacity that, in severe cases, may lead to inspiratory muscle fatigue and respiratory failure. Hyperinflation has been attributed to a passive mechanical origin; a respiratory system time-constant too long for full exhalation. However, because the increase in volume is also concurrent with activation of inspiratory muscles during exhalation it is unclear whether hyperinflation in broncho-constriction is a passive phenomenon or is actively controlled to avoid airway closure. Methods Using CT scanning, we measured the distensibility of individual segmental airways relative to that of their surrounding parenchyma in seven subjects with asthma and nine healthy controls. With this data we tested whether the elevation of lung volume measured after methacholine (MCh) provocation was associated with airway narrowing, or to the volume required to preventing airway closure. We also tested whether the reduction in FVC post-MCh could be attributed to gas trapped behind closed segmental airways. Findings The changes in lung volume by MCh in subjects with and without asthma were inversely associated with their reduction in average airway lumen. This finding would be inconsistent with hyperinflation by passive elevation of airway resistance. In contrast, the change in volume of each subject was associated with the lung volume estimated to cause the closure of the least stable segmental airway of his/her lungs. In addition, the measured drop in FVC post MCh was associated with the estimated volume of gas trapped behind closed segmental airways at RV. Conclusions Our data supports the concept that hyperinflation caused by MCh-induced bronchoconstriction is the result of an actively controlled process where parenchymal distending forces on airways are increased to counteract their closure. To our knowledge, this is the first imaging-based study that associates inter-subject differences in whole lung behavior with the interdependence between individual airways and their surrounding parenchyma.
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Affiliation(s)
- Juan S. Osorio-Valencia
- Department of Computer Science, Graduate Program in Biomedical Computing, Technical University of Munich, Munich, Germany
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (JSO); (JGV)
| | - Chanikarn Wongviriyawong
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Tilo Winkler
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Vanessa J. Kelly
- Department of Medicine, Pulmonary and Critical Care Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Robert S. Harris
- Department of Medicine, Pulmonary and Critical Care Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jose G. Venegas
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (JSO); (JGV)
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Ortiz G, Garay M, Capelozzi V, Cardinal-Fernández P. Airway Pathological Alterations Selectively Associated With Acute Respiratory Distress Syndrome and Diffuse Alveolar Damage - Narrative Review. Arch Bronconeumol 2018; 55:31-37. [PMID: 29853259 DOI: 10.1016/j.arbres.2018.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/16/2018] [Accepted: 03/07/2018] [Indexed: 12/12/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a frequent and life-threatening entity. Recently, it has been demonstrated that diffuse alveolar damage (DAD), which is considered the histological hallmark in spite of presenting itself in only half of living patients with ARDS, exerts a relevant effect in the ARDS outcome. Despite the fact that the bronchial tree constitutes approximately 1% of the lung volume, discovering a relation between DAD and bronchial tree findings could be of paramount importance for a few reasons; (a) it could improve the description of ARDS with DAD as a clinical-pathological entity, (b) it could subrogate DAD findings with the advantage of their more accessible and safer analysis and (c) it could allow the discovery of new therapeutic targets. This narrative review is focused on pathological airway changes associated to Diffuse Alveolar Damage in the context of Acute Respiratory Distress Syndrome. It is organized into five sections: main anatomical and functional features of the human airway, why it is necessary to study airway features associated to DAD in patients with ARDS, pathological airway changes associated with DAD in animal models of ARDS, pathological airway changes associated with DAD in patients with ARDS, and the newest techniques for studying the histology of the bronchial tree and lung parenchyma.
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Affiliation(s)
- Guillermo Ortiz
- Universidad del Bosque, Bogotá, Colombia; Universidad de Barcelona, Barcelona, Spain
| | | | - Vera Capelozzi
- Department of Pathology, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Pablo Cardinal-Fernández
- Emergency Department, Hospital Universitario HM Sanchinarro, Madrid, Spain; HM Research Foundation, Madrid, Spain.
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Servais AB, Valenzuela CD, Ysasi AB, Wagner WL, Kienzle A, Loring SH, Tsuda A, Ackermann M, Mentzer SJ. Pressure-decay testing of pleural air leaks in intact murine lungs: evidence for peripheral airway regulation. Physiol Rep 2018; 6:e13712. [PMID: 29845759 PMCID: PMC5974726 DOI: 10.14814/phy2.13712] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 11/24/2022] Open
Abstract
The critical care management of pleural air leaks can be challenging in all patients, but particularly in patients on mechanical ventilation. To investigate the effect of central airway pressure and pleural pressure on pulmonary air leaks, we studied orotracheally intubated mice with pleural injuries. We used clinically relevant variables - namely, airway pressure and pleural pressure - to investigate flow through peripheral air leaks. The model studied the pleural injuries using a pressure-decay maneuver. The pressure-decay maneuver involved a 3 sec ramp to 30 cmH2 0 followed by a 3 sec breath hold. After pleural injury, the pressure-decay maneuver demonstrated a distinctive airway pressure time history. Peak inflation was followed by a rapid decrease to a lower plateau phase. The decay phase of the inflation maneuver was influenced by the injury area. The rate of pressure decline with multiple injuries (28 ± 8 cmH2 0/sec) was significantly greater than a single injury (12 ± 3 cmH2 O/sec) (P < 0.05). In contrast, the plateau phase pressure was independent of injury surface area, but dependent upon transpulmonary pressure. The mean plateau transpulmonary pressure was 18 ± 0.7 cm H2 O. Finally, analysis of the inflation ramp demonstrated that nearly all volume loss occurred at the end of inflation (P < 0.001). We conclude that the air flow through peripheral lung injuries was greatest at increased lung volumes and limited by peripheral airway closure. In addition to suggesting an intrinsic mechanism for limiting flow through peripheral air leaks, these findings suggest the utility of positive end-expiratory pressure and negative pleural pressure to maintain lung volumes in patients with pleural injuries.
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Affiliation(s)
- Andrew B. Servais
- Laboratory of Adaptive and Regenerative BiologyBrigham & Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Cristian D. Valenzuela
- Laboratory of Adaptive and Regenerative BiologyBrigham & Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Alexandra B. Ysasi
- Laboratory of Adaptive and Regenerative BiologyBrigham & Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Willi L. Wagner
- Laboratory of Adaptive and Regenerative BiologyBrigham & Women's HospitalHarvard Medical SchoolBostonMassachusetts
- Institute of Functional and Clinical AnatomyUniversity Medical Center of the Johannes Gutenberg‐UniversityMainzGermany
| | - Arne Kienzle
- Laboratory of Adaptive and Regenerative BiologyBrigham & Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Stephen H. Loring
- Department of Anesthesia, Critical Care, and Pain MedicineBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMassachusetts
| | - Akira Tsuda
- Molecular and Integrative Physiological SciencesHarvard School of Public HealthBostonMassachusetts
| | - Maximilian Ackermann
- Institute of Functional and Clinical AnatomyUniversity Medical Center of the Johannes Gutenberg‐UniversityMainzGermany
| | - Steven J. Mentzer
- Laboratory of Adaptive and Regenerative BiologyBrigham & Women's HospitalHarvard Medical SchoolBostonMassachusetts
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Taher H, Bauer C, Abston E, Kaczka DW, Bhatt SP, Zabner J, Brower RG, Beichel RR, Eberlein M. Chest wall strapping increases expiratory airflow and detectable airway segments in computer tomographic scans of normal and obstructed lungs. J Appl Physiol (1985) 2018; 124:1186-1193. [PMID: 29357485 PMCID: PMC6008079 DOI: 10.1152/japplphysiol.00184.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 12/22/2017] [Accepted: 12/28/2017] [Indexed: 11/22/2022] Open
Abstract
Chest wall strapping (CWS) induces breathing at low lung volumes but also increases parenchymal elastic recoil. In this study, we tested the hypothesis that CWS dilates airways via airway-parenchymal interdependence. In 11 subjects (6 healthy and 5 with mild to moderate COPD), pulmonary function tests and lung volumes were obtained in control (baseline) and the CWS state. Control and CWS-CT scans were obtained at 50% of control (baseline) total lung-capacity (TLC). CT lung volumes were analyzed by CT volumetry. If control and CWS-CT volumetry did not differ by more than 25%, airway dimensions were analyzed via automated airway segmentation. CWS-TLC was reduced on average to 71% of control-TLC in normal subjects and 79% of control-TLC in subjects with COPD. CWS increased expiratory airflow at 50% of control-TLC by 41% (3.50 ± 1.6 vs. 4.93 ± 1.9 l/s, P = 0.04) in normals and 316% in COPD(0.25 ± 0.05 vs 0.79 ± 0.39 l/s, P = 0.04). In 10 subjects (5 normals and 5 COPD), control and CWS-CT scans at 50% control-TLC did not differ more than 25% on CT volumetry and were included in the airway structure analysis. CWS increased the mean number of detectable airways with a diameter of ≤2 mm by 32.5% (65 ± 10 vs. 86 ± 124, P = 0.01) in normal subjects and by 79% (59 ± 19 vs. 104 ± 16, P = 0.01) in subjects with COPD. There was no difference in the number of detectable airways with diameters 2-4 mm and >4 mm in normal or in COPD subjects. In conclusion, CWS enhances the detection of small airways via automated CT airway segmentation and increases expiratory airflow in normal subjects as well as in subjects with mild to moderate COPD. NEW & NOTEWORTHY In normal and COPD subjects, chest wall strapping(CWS) increased the number of detectable small airways using automated CT airway segmentation. The concept of dysanapsis expresses the physiological variation in the geometry of the tracheobronchial tree and lung parenchyma based on development. We propose a dynamic concept to dysanapsis in which CWS leads to breathing at lower lung volumes with a corresponding increase in the size of small airways, a potentially novel, nonpharmacological treatment for COPD.
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Affiliation(s)
- Hisham Taher
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
| | - Christian Bauer
- Department of Electrical and Computer Engineering, University of Iowa , Iowa City, Iowa
- Iowa Institute for Biomedical Imaging, University of Iowa , Iowa City, Iowa
| | - Eric Abston
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
| | - David W Kaczka
- Department of Anesthesiology, University of Iowa , Iowa City, Iowa
- Department of Biomedical Engineering, University of Iowa , Iowa City, Iowa
- Department of Radiology, University of Iowa , Iowa City, Iowa
| | - Surya P Bhatt
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama , Birmingham, Alabama
| | - Joseph Zabner
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
| | - Roy G Brower
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University - Baltimore, Maryland
| | - Reinhard R Beichel
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
- Department of Electrical and Computer Engineering, University of Iowa , Iowa City, Iowa
- Iowa Institute for Biomedical Imaging, University of Iowa , Iowa City, Iowa
| | - Michael Eberlein
- Department and Internal Medicine, University of Iowa , Iowa City, Iowa
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa , Iowa City, Iowa
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Lortie K, Maheux C, Gendron D, Langlois A, Beaulieu MJ, Marsolais D, Bossé Y, Blanchet MR. CD34 Differentially Regulates Contractile and Noncontractile Elements of Airway Reactivity. Am J Respir Cell Mol Biol 2018; 58:79-88. [PMID: 28850257 DOI: 10.1165/rcmb.2017-0008oc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Airway hyperresponsiveness (AHR), a major hallmark of asthma, results from alterations of contractile and noncontractile elements of airway reactivity. CD34 is a sialomucin that is expressed on various cells involved in asthma, such as eosinophils and airway smooth muscle precursors, highlighting its potential influence in AHR. To study the role of CD34 in regulating the contractile and noncontractile elements of AHR, AHR was induced by chronic exposure to house dust mite (HDM) antigen. To assess the role of CD34 on the contractile elements of AHR, airway reactivity and airway smooth muscle contractility in response to methacholine were measured. To assess CD34's role in regulating the noncontractile elements of AHR, a chimeric mouse model was used to determine the impact of CD34 expression on inflammatory versus microenvironmental cells in AHR development. Extracellular matrix production, mucus production, and mast cell degranulation were also measured. Whereas wild-type mice developed AHR in response to HDM, a loss of airway reactivity was observed in Cd34-/- mice 24 hours after the last exposure to HDM compared with naive controls. This was reversed when airway reactivity was measured 1 week after the last HDM exposure. Additionally, mast cell degranulation and mucus production were altered in the absence of CD34 expression. Importantly, simultaneous expression of CD34 on cells originating from the hematopoietic compartment and the microenvironment was needed for expression of this phenotype. These results provide evidence that CD34 is required for AHR and airway reactivity maintenance in the early days after an inflammatory episode in asthma.
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Affiliation(s)
- Katherine Lortie
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - Catherine Maheux
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - David Gendron
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - Anick Langlois
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - Marie-Josée Beaulieu
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - David Marsolais
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
| | - Marie-Renée Blanchet
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Quebec, Canada
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Gazzola M, Mailhot-Larouche S, Beucher C, Bossé Y. The underlying physiological mechanisms whereby anticholinergics alleviate asthma. Can J Physiol Pharmacol 2018; 96:433-441. [PMID: 29414243 DOI: 10.1139/cjpp-2017-0448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The mechanisms whereby anticholinergics improve asthma outcomes, such as lung function, symptoms, and rate of exacerbation, can be numerous. The most obvious is by affecting the contraction of airway smooth muscle (ASM). The acetylcholine released from the cholinergic nerves is the most important bronchoconstrictor that sets the baseline degree of contractile activation of ASM in healthy individuals. Although the degree of ASM's contractile activation can also be fine-tuned by a plethora of other bronchoconstrictors and bronchodilators in asthma, blocking the ceaseless effect of acetylcholine on ASM by anticholinergics reduces, at any given moment, the overall degree of contractile activation. Because the relationships that exist between the degree of contractile activation, ASM force, ASM shortening, airway narrowing, airflow resistance, and respiratory resistance are not linear, small decreases in the contractile activation of ASM can be greatly amplified and thus translate into important benefits to a patient's well-being. Plus, many inflammatory and remodeling features that are often found in asthmatic lungs synergize with the contractile activation of ASM to increase respiratory resistance. This review recalls that the proven effectiveness of anticholinergics in the treatment of asthma could be merely attributed to a small reduction in the contractile activation of ASM.
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Affiliation(s)
- Morgan Gazzola
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Samuel Mailhot-Larouche
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Clémentine Beucher
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Ynuk Bossé
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
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Kropski JA, Richmond BW, Gaskill CF, Foronjy RF, Majka SM. Deregulated angiogenesis in chronic lung diseases: a possible role for lung mesenchymal progenitor cells (2017 Grover Conference Series). Pulm Circ 2017; 8:2045893217739807. [PMID: 29040010 PMCID: PMC5731726 DOI: 10.1177/2045893217739807] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Chronic lung disease (CLD), including pulmonary fibrosis (PF) and chronic obstructive pulmonary disease (COPD), is the fourth leading cause of mortality worldwide. Both are debilitating pathologies that impede overall tissue function. A common co-morbidity in CLD is vasculopathy, characterized by deregulated angiogenesis, remodeling, and loss of microvessels. This substantially worsens prognosis and limits survival, with most current therapeutic strategies being largely palliative. The relevance of angiogenesis, both capillary and lymph, to the pathophysiology of CLD has not been resolved as conflicting evidence depicts angiogenesis as both reparative or pathologic. Therefore, we must begin to understand and model the underlying pathobiology of pulmonary vascular deregulation, alone and in response to injury induced disease, to define cell interactions necessary to maintain normal function and promote repair. Capillary and lymphangiogenesis are deregulated in both PF and COPD, although the mechanisms by which they co-regulate and underlie early pathogenesis of disease are unknown. The cell-specific mechanisms that regulate lung vascular homeostasis, repair, and remodeling represent a significant gap in knowledge, which presents an opportunity to develop targeted therapies. We have shown that that ABCG2pos multipotent adult mesenchymal stem or progenitor cells (MPC) influence the function of the capillary microvasculature as well as lymphangiogenesis. A balance of both is required for normal tissue homeostasis and repair. Our current models suggest that when lymph and capillary angiogenesis are out of balance, the non-equivalence appears to support the progression of disease and tissue remodeling. The angiogenic regulatory mechanisms underlying CLD likely impact other interstitial lung diseases, tuberous sclerosis, and lymphangioleiomyomatosis.
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Affiliation(s)
- Jonathan A Kropski
- 1 12328 Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bradley W Richmond
- 1 12328 Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Christa F Gaskill
- 1 12328 Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robert F Foronjy
- 3 5718 Department of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Susan M Majka
- 1 12328 Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.,2 74498 Department of Medicine, Division of Pulmonary and Critical Care Medicine, SUNY Downstate Medical Center, Brooklyn, NY, USA
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41
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Abston E, Comellas A, Reed RM, Kim V, Wise RA, Brower R, Fortis S, Beichel R, Bhatt S, Zabner J, Newell J, Hoffman EA, Eberlein M. Higher BMI is associated with higher expiratory airflow normalised for lung volume (FEF25-75/FVC) in COPD. BMJ Open Respir Res 2017; 4:e000231. [PMID: 29071083 PMCID: PMC5652498 DOI: 10.1136/bmjresp-2017-000231] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/04/2017] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION The obesity paradox in chronic obstructive pulmonary disease (COPD), whereby patients with higher body mass index (BMI) fare better, is poorly understood. Higher BMIs are associated with lower lung volumes and greater lung elastic recoil, a key determinant of expiratory airflow. The forced expiratory flow (25-75) (FEF25-75)/forced vital capacity (FVC) ratio reflects effort-independent expiratory airflow in the context of lung volume and could be modulated by BMI. METHODS We analysed data from the COPDGene study, an observational study of 10 192 subjects, with at least a 10 pack-year smoking history. Data were limited to subjects with BMI 20-40 kg/m2 (n=9222). Subjects were stratified according to forced expiratory volume in 1 s (FEV1) (%predicted)-quintiles. In regression analyses and Cox proportional hazard models, we analysed the association between BMI, the FEF25-75/FVC ratio, the imaging phenotype, COPD exacerbations, hospitalisations and death. RESULTS There was no correlation between BMI and FEV1(%predicted). However, a higher BMI is correlated with a higher FEF25-75/FVC ratio. In CT scans, a higher BMI was associated with less emphysema and less air trapping. In risk-adjusted models, the quintile with the highest FEF25-75/FVC ratio was associated with a 46% lower risk of COPD exacerbations (OR 0.54, p<0.001) and a 40% lower risk of death (HR 0.60, p=0.02), compared with the lowest quintile. BMI was not independently associated with these outcomes. CONCLUSIONS A higher BMI is associated with lower lung volumes and higher expiratory airflows when normalised for lung volume, as quantified by the FEF25-75/FVC ratio. A higher FEF25-75/FVC ratio is associated with a lower risk of COPD exacerbations and death and might quantify functional aspects of the paradoxical effect of higher BMIs on COPD.
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Affiliation(s)
- Eric Abston
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Alejandro Comellas
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Robert Michael Reed
- Division of Pulmonary and Critical Care Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Victor Kim
- Division of Pulmonary and Critical Care Medicine, Temple University, School of Medicine, Philadelphia, Pennsylvania, USA
| | - Robert A Wise
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Roy Brower
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Spyridon Fortis
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Reinhard Beichel
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, USA
- The Iowa Institute for Biomedical Imaging, University of Iowa, University of Iowa, Iowa City, Iowa, USA
| | - Surya Bhatt
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama, Birmingham, Alabama, USA
| | - Joseph Zabner
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa, Iowa City, Iowa, USA
| | - John Newell
- The Iowa Institute for Biomedical Imaging, University of Iowa, University of Iowa, Iowa City, Iowa, USA
- Department of Radiology, University of Iowa, Iowa, USA
| | - Eric A Hoffman
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, USA
- The Iowa Institute for Biomedical Imaging, University of Iowa, University of Iowa, Iowa City, Iowa, USA
- Department of Radiology, University of Iowa, Iowa, USA
| | - Michael Eberlein
- Department of Medicine, University of Iowa, Iowa City, Iowa, USA
- Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa, Iowa City, Iowa, USA
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Santus P, Radovanovic D, Balzano G, Pecchiari M, Raccanelli R, Sarno N, Di Marco F, Jones PW, Carone M. Improvements in Lung Diffusion Capacity following Pulmonary Rehabilitation in COPD with and without Ventilation Inhomogeneity. Respiration 2016; 92:295-307. [PMID: 27598467 DOI: 10.1159/000448847] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 08/03/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Lung diffusing capacity (DLCO) and lung volume distribution predict exercise performance and are altered in COPD patients. If pulmonary rehabilitation (PR) can modify DLCO parameters is unknown. OBJECTIVES To investigate changes in DLCO and ventilation inhomogeneity following a PR program and their relation with functional outcomes in patients with COPD. METHODS This was a prospective, observational, multicentric study. Patients were evaluated before and after a standardized 3-week PR program. Functional assessment included body plethysmography, DLCO, transfer factor (KCO) and alveolar volume (VA), gas exchange, the 6-min walking test (6MWT) and exercise-related dyspnea. Patients were categorized according to the severity of airflow limitation and presence of ventilation inhomogeneity, identified by a VA/TLC <0.8. RESULTS Two hundred and fifty patients completed the study. Baseline forced expiratory volume in 1 s (FEV1) % predicted (mean ± SD) was 50.5 ± 20.1 (76% males); 137 patients had a severe disease. General study population showed improvements in 6MWT (38 ± 55 m; p < 0.01), DLCO (0.12 ± 0.63 mmol × min-1 kPa-1; p < 0.01), lung function and dyspnea. Comparable improvements in DLCO were observed regardless of the severity of disease and the presence of ventilation inhomogeneity. While patients with VA/TLC <0.8 improved the DLCO increasing their VA (177 ± 69 ml; p < 0.01), patients with VA/TLC >0.8 improved their KCO (8.1 ± 2.8%; p = 0.019). The latter had also better baseline lung function and higher improvements in 6MWT (14.6 ± 6.7 vs. 9.0 ± 1.8%; p = 0.015). Lower DLCO at baseline was associated with lower improvements in 6MWT, the greatest difference being between subjects with very severe and mild DLCO impairment (2.7 ± 7.4 vs. 14 ± 2%; p = 0.049). CONCLUSIONS In COPD patients undergoing a PR program, different pathophysiological mechanisms may drive improvements in DLCO, while ventilation inhomogeneity may limit improvements in exercise tolerance.
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Affiliation(s)
- Pierachille Santus
- Department of Health Science, University of Milan, Pulmonary Rehabilitation Unit, Fondazione Salvatore Maugeri, IRCCS - Scientific Institute of Milan, Milan, Italy
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Donovan GM. Systems-level airway models of bronchoconstriction. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2016; 8:459-67. [PMID: 27348217 DOI: 10.1002/wsbm.1349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/23/2016] [Accepted: 05/18/2016] [Indexed: 01/26/2023]
Abstract
Understanding lung and airway behavior presents a number of challenges, both experimental and theoretical, but the potential rewards are great in terms of both potential treatments for disease and interesting biophysical phenomena. This presents an opportunity for modeling to contribute to greater understanding, and here, we focus on modeling efforts that work toward understanding the behavior of airways in vivo, with an emphasis on asthma. We look particularly at those models that address not just isolated airways but many of the important ways in which airways are coupled both with each other and with other structures. This includes both interesting phenomena involving the airways and the layer of airway smooth muscle that surrounds them, and also the emergence of spatial ventilation patterns via dynamic airway interaction. WIREs Syst Biol Med 2016, 8:459-467. doi: 10.1002/wsbm.1349 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
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Khan MA. Dynamics of airway response in lung microsections: a tool for studying airway-extra cellular matrix interactions. J Biomed Sci 2016; 23:43. [PMID: 27176036 PMCID: PMC4865010 DOI: 10.1186/s12929-016-0263-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/06/2016] [Indexed: 01/27/2023] Open
Abstract
The biological configuration of extracellular matrix (ECM) plays a key role in how mechanical interactions of the airway with its parenchymal attachments affect the dynamics of airway responses in different pulmonary disorders including asthma, emphysema and chronic bronchitis. It is now recognized that mechanical interactions between airway tissue and ECM play a key regulatory role on airway physiology and kinetics that can lead to the reorganization and remodeling of airway connective tissue. A connective tissue is composed of airway smooth muscle cells (ASM) and the ECM, which includes variety of glycoproteins and therefore the extent of interactions between ECM and ASM affects airway dynamics during exacerbations of major pulmonary disorders. Measurement of the velocity and magnitude of airway closure or opening provide important insights into the functions of the airway contractile apparatus and the interactions with its surrounding connective tissues. This review highlights suitability of lung microsection technique in studying measurements of airway dynamics (narrowing/opening) and associated structural distortions in airway compartments.
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Affiliation(s)
- Mohammad Afzal Khan
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh, 11211, Kingdom of Saudi Arabiana.
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Fain SB, Sorkness RL. Using MRI to Reveal (and Resolve) the Complexity of Obstructive Lung Disease. Acad Radiol 2016; 23:393-5. [PMID: 26944310 DOI: 10.1016/j.acra.2016.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 01/08/2023]
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Buehler S, Schumann S, Vimláti L, Lichtwarck-Aschoff M, Guttmann J. Simultaneous monitoring of intratidal compliance and resistance in mechanically ventilated piglets: A feasibility study in two different study groups. Respir Physiol Neurobiol 2015; 219:36-42. [PMID: 26275684 DOI: 10.1016/j.resp.2015.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 11/30/2022]
Abstract
Compliance measures the force counteracting parenchymal lung distension. In mechanical ventilation, intratidal compliance-volume (C(V))-profiles therefore change depending on PEEP, tidal volume (VT), and underlying mechanical lung properties. Resistance counteracts gas flow through the airways. Due to anatomical linking between parenchyma and airways, intratidal resistance-volume (R(V))-profiles are hypothesised to change in a non-linear way as well. We analysed respiratory system mechanics in fifteen piglets with lavage-induced lung injury and nine healthy piglets ventilated at different PEEP/VT-settings. In healthy lungs, R(V)-profiles remained mostly constant and linear at all PEEP-settings whereas the shape of the C(V)-profiles showed an increase toward a maximum followed by a decrease (small PEEP) or volume-dependent decrease (large PEEP). In the lavage group, a large drop in resistance at small volumes and slow decrease toward larger volumes was found for small PEEP/VT-settings where C(V)-profiles revealed a volume-dependent increase (small PEEP) or a decrease (large PEEP and large VT). R(V)-profiles depend characteristically on PEEP, VT, and possibly whether lungs are healthy or not. Curved R(V)-profiles might indicate pathological changes in the underlying mechanical lung properties and/or might be a sign of derecruitment.
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Affiliation(s)
- Sarah Buehler
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Germany.
| | - Stefan Schumann
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Germany.
| | - László Vimláti
- Department of Surgical Sciences, Uppsala University, Sweden.
| | | | - Josef Guttmann
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Germany.
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Limjunyawong N, Fallica J, Horton MR, Mitzner W. Measurement of the pressure-volume curve in mouse lungs. J Vis Exp 2015:52376. [PMID: 25651276 DOI: 10.3791/52376] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In recent decades the mouse has become the primary animal model of a variety of lung diseases. In models of emphysema or fibrosis, the essential phenotypic changes are best assessed by measurement of the changes in lung elasticity. To best understand specific mechanisms underlying such pathologies in mice, it is essential to make functional measurements that can reflect the developing pathology. Although there are many ways to measure elasticity, the classical method is that of the total lung pressure-volume (PV) curve done over the whole range of lung volumes. This measurement has been made on adult lungs from nearly all mammalian species dating back almost 100 years, and such PV curves also played a major role in the discovery and understanding of the function of pulmonary surfactant in fetal lung development. Unfortunately, such total PV curves have not been widely reported in the mouse, despite the fact that they can provide useful information on the macroscopic effects of structural changes in the lung. Although partial PV curves measuring just the changes in lung volume are sometimes reported, without a measure of absolute volume, the nonlinear nature of the total PV curve makes these partial ones very difficult to interpret. In the present study, we describe a standardized way to measure the total PV curve. We have then tested the ability of these curves to detect changes in mouse lung structure in two common lung pathologies, emphysema and fibrosis. Results showed significant changes in several variables consistent with expected structural changes with these pathologies. This measurement of the lung PV curve in mice thus provides a straightforward means to monitor the progression of the pathophysiologic changes over time and the potential effect of therapeutic procedures.
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Affiliation(s)
- Nathachit Limjunyawong
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University
| | - Jonathan Fallica
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University
| | - Maureen R Horton
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University
| | - Wayne Mitzner
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University;
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