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Kim KT, Knopp J, Dixon B, Chase JG. Quantifying neonatal patient effort using non-invasive model-based methods. Med Biol Eng Comput 2022; 60:739-751. [PMID: 35043368 DOI: 10.1007/s11517-021-02491-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
Patient-specific spontaneous breathing effort (SB) is common in invasively mechanically ventilated (MV) adult patients, and especially common in preterm neonates who are not typically sedated. However, there is no proven, ethically feasible and non-invasive method to quantify SB effort in neonates, creating the potential for model-based measures. Lung mechanics and SB effort are segregated using a basis function model to identify passive lung mechanics, and an additional time-varying elastance model to identify patient-specific SB effort and asynchrony as negative and positive added elastances, respectively. Data from ten preterm neonates on standard MV care in the neonatal intensive care unit (NICU) are used to assess this model-based approach, using area under the curve (AUC) for positive (asynchrony) and negative (SB effort) time-varying elastance. Median [interquartile-range (IQR)] of passive pulmonary lung elastance was 3.82 [2.09-5.80] cmH2O/ml. Median [IQR] AUC quantified SB effort was -0.32 [-0.43--0.12]cmH2O/ml. AUC quantified asynchrony was 0.00 [0.00-0.01]cmH2O/ml, and affected 28% of the 25,287 total breaths. This proof of concept model-based approach provides a non-invasive, computationally straightforward, and thus clinically feasible means to quantify patient-specific spontaneous breathing effort and asynchrony.
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Affiliation(s)
- Kyeong Tae Kim
- Centre for Bioengineering, University of Canterbury, Christchurch, New Zealand.
| | - Jennifer Knopp
- Centre for Bioengineering, University of Canterbury, Christchurch, New Zealand
| | - Bronwyn Dixon
- Neonatal Intensive Care Unit, Christchurch Women's Hospital, Christchurch, New Zealand
| | - J Geoffrey Chase
- Centre for Bioengineering, University of Canterbury, Christchurch, New Zealand
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2
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Zannin E, Aarli BB, Govoni L, Pompilio PP, Baldi S, Hardie JA, Dellacà RL. Effect of stimulating waveform and of data processing on respiratory impedance measurement. Physiol Meas 2020; 41:055005. [DOI: 10.1088/1361-6579/ab87b1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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3
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Chase JG, Preiser JC, Dickson JL, Pironet A, Chiew YS, Pretty CG, Shaw GM, Benyo B, Moeller K, Safaei S, Tawhai M, Hunter P, Desaive T. Next-generation, personalised, model-based critical care medicine: a state-of-the art review of in silico virtual patient models, methods, and cohorts, and how to validation them. Biomed Eng Online 2018; 17:24. [PMID: 29463246 PMCID: PMC5819676 DOI: 10.1186/s12938-018-0455-y] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 02/12/2018] [Indexed: 01/17/2023] Open
Abstract
Critical care, like many healthcare areas, is under a dual assault from significantly increasing demographic and economic pressures. Intensive care unit (ICU) patients are highly variable in response to treatment, and increasingly aging populations mean ICUs are under increasing demand and their cohorts are increasingly ill. Equally, patient expectations are growing, while the economic ability to deliver care to all is declining. Better, more productive care is thus the big challenge. One means to that end is personalised care designed to manage the significant inter- and intra-patient variability that makes the ICU patient difficult. Thus, moving from current "one size fits all" protocolised care to adaptive, model-based "one method fits all" personalised care could deliver the required step change in the quality, and simultaneously the productivity and cost, of care. Computer models of human physiology are a unique tool to personalise care, as they can couple clinical data with mathematical methods to create subject-specific models and virtual patients to design new, personalised and more optimal protocols, as well as to guide care in real-time. They rely on identifying time varying patient-specific parameters in the model that capture inter- and intra-patient variability, the difference between patients and the evolution of patient condition. Properly validated, virtual patients represent the real patients, and can be used in silico to test different protocols or interventions, or in real-time to guide care. Hence, the underlying models and methods create the foundation for next generation care, as well as a tool for safely and rapidly developing personalised treatment protocols over large virtual cohorts using virtual trials. This review examines the models and methods used to create virtual patients. Specifically, it presents the models types and structures used and the data required. It then covers how to validate the resulting virtual patients and trials, and how these virtual trials can help design and optimise clinical trial. Links between these models and higher order, more complex physiome models are also discussed. In each section, it explores the progress reported up to date, especially on core ICU therapies in glycemic, circulatory and mechanical ventilation management, where high cost and frequency of occurrence provide a significant opportunity for model-based methods to have measurable clinical and economic impact. The outcomes are readily generalised to other areas of medical care.
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Affiliation(s)
- J. Geoffrey Chase
- Department of Mechanical Engineering, Centre for Bio-Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Jean-Charles Preiser
- Department of Intensive Care, Erasme University of Hospital, 1070 Brussels, Belgium
| | - Jennifer L. Dickson
- Department of Mechanical Engineering, Centre for Bio-Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Antoine Pironet
- GIGA In Silico Medicine, University of Liege, 4000 Liege, Belgium
| | - Yeong Shiong Chiew
- Department of Mechanical Engineering, School of Engineering, Monash University Malaysia, 47500 Selangor, Malaysia
| | - Christopher G. Pretty
- Department of Mechanical Engineering, Centre for Bio-Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Geoffrey M. Shaw
- Department of Intensive Care, Christchurch Hospital, Christchurch, New Zealand
| | - Balazs Benyo
- Department of Control Engineering and Information Technology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Knut Moeller
- Department of Biomedical Engineering, Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Soroush Safaei
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Merryn Tawhai
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peter Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Thomas Desaive
- GIGA In Silico Medicine, University of Liege, 4000 Liege, Belgium
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4
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Hamamoto Y, Ano S, Allard B, O'Sullivan M, McGovern TK, Martin JG. Montelukast reduces inhaled chlorine triggered airway hyperresponsiveness and airway inflammation in the mouse. Br J Pharmacol 2017; 174:3346-3358. [PMID: 28718891 PMCID: PMC5595758 DOI: 10.1111/bph.13953] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 03/20/2017] [Accepted: 04/13/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Cysteinyl leukotrienes (CysLTs) are pro-inflammatory lipid mediators that exacerbate disease state in several asthma phenotypes including asthma induced by allergen, virus and exercise. However, the role of CysLTs in irritant-induced airway disease is not well characterized. The purpose of the current study was to investigate the effect of montelukast, a CysLT1 receptor antagonist, on parameters of irritant-induced asthma induced by inhalation of chlorine in the mouse. EXPERIMENTAL APPROACH BALB/c mice were exposed to chlorine in air (100 ppm, for 5 min). Montelukast (3 mg·kg-1 ) or the vehicle (1% methylcellulose) was administered 24 and 1 h prior to chlorine exposure and 1 h prior to outcome measurements. Twenty-four hours after exposure, responses to inhaled aerosolized methacholine, cell composition and an array of cytokines/chemokines in bronchoalveolar lavage (BAL) fluid were measured. Neutralizing antibodies against IL-6 and VEGF were administered prior to exposures. KEY RESULTS Montelukast reduced chlorine -induced airway hyperresponsiveness (AHR) to methacholine in the peripheral lung compartment as estimated from dynamic elastance, but not in large conducting airways. Montelukast treatment attenuated chlorine-induced macrophage influx, neutrophilia and eosinophilia in BAL fluid. Chlorine exposure increased VEGF, IL-6, the chemokines KC and CCL3 in BAL fluid. Montelukast treatment prevented chlorine-induced increases in VEGF and IL-6. Anti-IL-6 antibody inhibited chlorine-induced neutrophilia and reduced AHR. CONCLUSIONS AND IMPLICATIONS Pre-treatment with montelukast attenuated chlorine-induced neutrophilia and AHR in mice. These effects are mediated, in part, via IL-6.
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Affiliation(s)
- Yoichiro Hamamoto
- Meakins‐Christie Laboratories, The Research Institute of McGill University Health Centre and the Department of MedicineMcGill UniversityMontrealQCCanada
| | - Satoshi Ano
- Meakins‐Christie Laboratories, The Research Institute of McGill University Health Centre and the Department of MedicineMcGill UniversityMontrealQCCanada
| | - Benoit Allard
- Meakins‐Christie Laboratories, The Research Institute of McGill University Health Centre and the Department of MedicineMcGill UniversityMontrealQCCanada
| | - Michael O'Sullivan
- Meakins‐Christie Laboratories, The Research Institute of McGill University Health Centre and the Department of MedicineMcGill UniversityMontrealQCCanada
| | - Toby K McGovern
- Meakins‐Christie Laboratories, The Research Institute of McGill University Health Centre and the Department of MedicineMcGill UniversityMontrealQCCanada
| | - James G Martin
- Meakins‐Christie Laboratories, The Research Institute of McGill University Health Centre and the Department of MedicineMcGill UniversityMontrealQCCanada
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5
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Histologic and biochemical alterations predict pulmonary mechanical dysfunction in aging mice with chronic lung inflammation. PLoS Comput Biol 2017; 13:e1005570. [PMID: 28837561 PMCID: PMC5570219 DOI: 10.1371/journal.pcbi.1005570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 05/12/2017] [Indexed: 01/06/2023] Open
Abstract
Both aging and chronic inflammation produce complex structural and biochemical alterations to the lung known to impact work of breathing. Mice deficient in surfactant protein D (Sftpd) develop progressive age-related lung pathology characterized by tissue destruction/remodeling, accumulation of foamy macrophages and alteration in surfactant composition. This study proposes to relate changes in tissue structure seen in normal aging and in chronic inflammation to altered lung mechanics using a computational model. Alterations in lung function in aging and Sftpd -/- mice have been inferred from fitting simple mechanical models to respiratory impedance data (Zrs), however interpretation has been confounded by the simultaneous presence of multiple coexisting pathophysiologic processes. In contrast to the inverse modeling approach, this study uses simulation from experimental measurements to recapitulate how aging and inflammation alter Zrs. Histologic and mechanical measurements were made in C57BL6/J mice and congenic Sftpd-/- mice at 8, 27 and 80 weeks of age (n = 8/group). An anatomic computational model based on published airway morphometry was developed and Zrs was simulated between 0.5 and 20 Hz. End expiratory pressure dependent changes in airway caliber and recruitment were estimated from mechanical measurements. Tissue elements were simulated using the constant phase model of viscoelasticity. Baseline elastance distribution was estimated in 8-week-old wild type mice, and stochastically varied for each condition based on experimentally measured alteration in elastic fiber composition, alveolar geometry and surfactant composition. Weighing reduction in model error against increasing model complexity allowed for identification of essential features underlying mechanical pathology and their contribution to Zrs. Using a maximum likelihood approach, alteration in lung recruitment and diminished elastic fiber density were shown predictive of mechanical alteration at airway opening, to a greater extent than overt acinar wall destruction. Model-predicted deficits in PEEP-dependent lung recruitment correlate with altered lung lining fluid composition independent of age or genotype. Aging and chronic inflammation produce complex changes to the structure of the lung including accumulation of cells and debris, thinning and destruction of air sacs, altered airway size and increased tendency for airway collapse. As these structural changes are observed concurrently, their individual contributions to altered lung function cannot readily be determined by conventional measurement of lung function. Our study employs a novel approach to identifying the age progression of these effects in mice with and without chronic lung inflammation. Histologic changes in lung tissue were incorporated into a computational model of the mouse lung and used to simulate measured changes in lung function. By incorporating experimentally measured factors into the model in a stepwise fashion, the contribution of destructive and remodeling processes to alterations in lung function can be assessed. This modeling approach provides a framework for determining the significance of structural changes to the altered function observed in complex lung pathologies such as emphysema and chronic obstructive pulmonary disease. Such an approach could be utilized to assess mechanisms by which compounds alter lung function and the capacity of specific therapies to produce improvements in lung function at the organ level.
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6
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Gebe JA, Yadava K, Ruppert SM, Marshall P, Hill P, Falk BA, Sweere JM, Han H, Kaber G, Harten IA, Medina C, Mikecz K, Ziegler SF, Balaji S, Keswani SG, Perez VADJ, Butte MJ, Nadeau K, Altemeier WA, Fanger N, Bollyky PL. Modified High-Molecular-Weight Hyaluronan Promotes Allergen-Specific Immune Tolerance. Am J Respir Cell Mol Biol 2017; 56:109-120. [PMID: 27598620 DOI: 10.1165/rcmb.2016-0111oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The extracellular matrix in asthmatic lungs contains abundant low-molecular-weight hyaluronan, and this is known to promote antigen presentation and allergic responses. Conversely, high-molecular-weight hyaluronan (HMW-HA), typical of uninflamed tissues, is known to suppress inflammation. We investigated whether HMW-HA can be adapted to promote tolerance to airway allergens. HMW-HA was thiolated to prevent its catabolism and was tethered to allergens via thiol linkages. This platform, which we call "XHA," delivers antigenic payloads in the context of antiinflammatory costimulation. Allergen/XHA was administered intranasally to mice that had been sensitized previously to these allergens. XHA prevents allergic airway inflammation in mice sensitized previously to either ovalbumin or cockroach proteins. Allergen/XHA treatment reduced inflammatory cell counts, airway hyperresponsiveness, allergen-specific IgE, and T helper type 2 cell cytokine production in comparison with allergen alone. These effects were allergen specific and IL-10 dependent. They were durable for weeks after the last challenge, providing a substantial advantage over the current desensitization protocols. Mechanistically, XHA promoted CD44-dependent inhibition of nuclear factor-κB signaling, diminished dendritic cell maturation, and reduced the induction of allergen-specific CD4 T-helper responses. XHA and other potential strategies that target CD44 are promising alternatives for the treatment of asthma and allergic sinusitis.
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Affiliation(s)
- John A Gebe
- 1 Benaroya Research Institute, Seattle, Washington
| | - Koshika Yadava
- 2 Division of Infectious Diseases and Geographic Medicine, Department of Medicine.,3 Stanford Immunology, and
| | - Shannon M Ruppert
- 2 Division of Infectious Diseases and Geographic Medicine, Department of Medicine.,3 Stanford Immunology, and
| | | | | | | | - Johanna M Sweere
- 2 Division of Infectious Diseases and Geographic Medicine, Department of Medicine.,3 Stanford Immunology, and
| | - Hongwei Han
- 1 Benaroya Research Institute, Seattle, Washington
| | - Gernot Kaber
- 2 Division of Infectious Diseases and Geographic Medicine, Department of Medicine
| | | | - Carlos Medina
- 2 Division of Infectious Diseases and Geographic Medicine, Department of Medicine.,3 Stanford Immunology, and
| | - Katalin Mikecz
- 5 Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois
| | | | - Swathi Balaji
- 6 Division of Pediatric Surgery, Baylor College of Medicine, Houston, Texas; and
| | - Sundeep G Keswani
- 6 Division of Pediatric Surgery, Baylor College of Medicine, Houston, Texas; and
| | - Vinicio A de Jesus Perez
- 7 Division of Pulmonary and Critical Care, Stanford University Medical Center, Stanford University School of Medicine, Stanford, California
| | | | - Kari Nadeau
- 7 Division of Pulmonary and Critical Care, Stanford University Medical Center, Stanford University School of Medicine, Stanford, California
| | - William A Altemeier
- 8 Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington
| | | | - Paul L Bollyky
- 1 Benaroya Research Institute, Seattle, Washington.,2 Division of Infectious Diseases and Geographic Medicine, Department of Medicine.,3 Stanford Immunology, and
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7
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Chung KF, Seiffert J, Chen S, Theodorou IG, Goode AE, Leo BF, McGilvery CM, Hussain F, Wiegman C, Rossios C, Zhu J, Gong J, Tariq F, Yufit V, Monteith AJ, Hashimoto T, Skepper JN, Ryan MP, Zhang J, Tetley T, Porter AE. Inactivation, Clearance, and Functional Effects of Lung-Instilled Short and Long Silver Nanowires in Rats. ACS NANO 2017; 11:2652-2664. [PMID: 28221763 PMCID: PMC5371928 DOI: 10.1021/acsnano.6b07313] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 02/21/2017] [Indexed: 05/25/2023]
Abstract
There is a potential for silver nanowires (AgNWs) to be inhaled, but there is little information on their health effects and their chemical transformation inside the lungs in vivo. We studied the effects of short (S-AgNWs; 1.5 μm) and long (L-AgNWs; 10 μm) nanowires instilled into the lungs of Sprague-Dawley rats. S- and L-AgNWs were phagocytosed and degraded by macrophages; there was no frustrated phagocytosis. Interestingly, both AgNWs were internalized in alveolar epithelial cells, with precipitation of Ag2S on their surface as secondary Ag2S nanoparticles. Quantitative serial block face three-dimensional scanning electron microscopy showed a small, but significant, reduction of NW lengths inside alveolar epithelial cells. AgNWs were also present in the lung subpleural space where L-AgNWs exposure resulted in more Ag+ve macrophages situated within the pleura and subpleural alveoli, compared with the S-AgNWs exposure. For both AgNWs, there was lung inflammation at day 1, disappearing by day 21, but in bronchoalveolar lavage fluid (BALF), L-AgNWs caused a delayed neutrophilic and macrophagic inflammation, while S-AgNWs caused only acute transient neutrophilia. Surfactant protein D (SP-D) levels in BALF increased after S- and L-AgNWs exposure at day 7. L-AgNWs induced MIP-1α and S-AgNWs induced IL-18 at day 1. Large airway bronchial responsiveness to acetylcholine increased following L-AgNWs, but not S-AgNWs, exposure. The attenuated response to AgNW instillation may be due to silver inactivation after precipitation of Ag2S with limited dissolution. Our findings have important consequences for the safety of silver-based technologies to human health.
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Affiliation(s)
- Kian Fan Chung
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Joanna Seiffert
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Shu Chen
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Ioannis G. Theodorou
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Angela Erin Goode
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Bey Fen Leo
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
- Nanotechnology
and Catalysis Research Centre (NANOCAT), University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Catriona M. McGilvery
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Farhana Hussain
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Coen Wiegman
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Christos Rossios
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Jie Zhu
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Jicheng Gong
- Nicholas
School of Environment and Duke Global Health Institute, Duke University, Durham, North Carolina 27708, United States
| | - Farid Tariq
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Vladimir Yufit
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Alexander J. Monteith
- Department
of Biological Sciences, Oxford Brookes University, Oxford OX3 OBP, United Kingdom
| | - Teruo Hashimoto
- The
School of Materials, The University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - Jeremy N. Skepper
- Cambridge
Advanced Imaging Centre, Department of Anatomy, University of Cambridge, Tennis Court Road, Cambridge CB2 3DY United Kingdom
| | - Mary P. Ryan
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Junfeng Zhang
- Nicholas
School of Environment and Duke Global Health Institute, Duke University, Durham, North Carolina 27708, United States
| | - Teresa
D. Tetley
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
| | - Alexandra E. Porter
- Airways Disease, National Heart
and Lung Institute, Department of Materials and London
Centre for Nanotechnology, and Department of Earth Science, Imperial College, London SW7 2AZ, United Kingdom
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8
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Altemeier WA, Hung CF, Matute-Bello G. Mouse Models of Acute Lung Injury. ACUTE LUNG INJURY AND REPAIR 2017. [DOI: 10.1007/978-3-319-46527-2_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Siddiqui S, Tsuchiya K, Risse PA, Bullimore SR, Benedetti A, Martin JG. Site of allergic airway narrowing and the influence of exogenous surfactant in the Brown Norway rat. PLoS One 2012; 7:e29381. [PMID: 22276110 PMCID: PMC3261862 DOI: 10.1371/journal.pone.0029381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 11/28/2011] [Indexed: 11/18/2022] Open
Abstract
Background The parameters RN (Newtonian resistance), G (tissue damping), and H (tissue elastance) of the constant phase model of respiratory mechanics provide information concerning the site of altered mechanical properties of the lung. The aims of this study were to compare the site of allergic airway narrowing implied from respiratory mechanics to a direct assessment by morphometry and to evaluate the effects of exogenous surfactant administration on the site and magnitude of airway narrowing. Methods We induced airway narrowing by ovalbumin sensitization and challenge and we tested the effects of a natural surfactant lacking surfactant proteins A and D (Infasurf®) on airway responses. Sensitized, mechanically ventilated Brown Norway rats underwent an aerosol challenge with 5% ovalbumin or vehicle. Other animals received nebulized surfactant prior to challenge. Three or 20 minutes after ovalbumin challenge, airway luminal areas were assessed on snap-frozen lungs by morphometry. Results At 3 minutes, RN and G detected large airway narrowing whereas at 20 minutes G and H detected small airway narrowing. Surfactant inhibited RN at the peak of the early allergic response and ovalbumin-induced increase in bronchoalveolar lavage fluid cysteinyl leukotrienes and amphiregulin but not IgE-induced mast cell activation in vitro. Conclusion Allergen challenge triggers the rapid onset of large airway narrowing, detected by RN and G, and subsequent peripheral airway narrowing detected by G and H. Surfactant inhibits airway narrowing and reduces mast cell-derived mediators.
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Affiliation(s)
- Sana Siddiqui
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Kimitake Tsuchiya
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Paul-André Risse
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Sharon R. Bullimore
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Andrea Benedetti
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - James G. Martin
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
- * E-mail:
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10
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Kaczka DW, Dellacá RL. Oscillation mechanics of the respiratory system: applications to lung disease. Crit Rev Biomed Eng 2011; 39:337-59. [PMID: 22011237 DOI: 10.1615/critrevbiomedeng.v39.i4.60] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Since its introduction in the 1950s, the forced oscillation technique (FOT) and the measurement of respiratory impedance have evolved into powerful tools for the assessment of various mechanical phenomena in the mammalian lung during health and disease. In this review, we highlight the most recent developments in instrumentation, signal processing, and modeling relevant to FOT measurements. We demonstrate how FOT provides unparalleled information on the mechanical status of the respiratory system compared to more widely used pulmonary function tests. The concept of mechanical impedance is reviewed, as well as the various measurement techniques used to acquire such data. Emphasis is placed on the analysis of lower, physiologic frequency ranges (typically less than 10 Hz) that are most sensitive to normal physical processes as well as pathologic structural alterations. Various inverse modeling approaches used to interpret alterations in impedance are also discussed, specifically in the context of three common respiratory diseases: asthma, chronic obstructive pulmonary disease, and acute lung injury. Finally, we speculate on the potential role for FOT in the clinical arena.
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Affiliation(s)
- David W Kaczka
- Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, USA.
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11
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Reiss LK, Kowallik A, Uhlig S. Recurrent recruitment manoeuvres improve lung mechanics and minimize lung injury during mechanical ventilation of healthy mice. PLoS One 2011; 6:e24527. [PMID: 21935418 PMCID: PMC3174196 DOI: 10.1371/journal.pone.0024527] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 08/12/2011] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Mechanical ventilation (MV) of mice is increasingly required in experimental studies, but the conditions that allow stable ventilation of mice over several hours have not yet been fully defined. In addition, most previous studies documented vital parameters and lung mechanics only incompletely. The aim of the present study was to establish experimental conditions that keep these parameters within their physiological range over a period of 6 h. For this purpose, we also examined the effects of frequent short recruitment manoeuvres (RM) in healthy mice. METHODS Mice were ventilated at low tidal volume V(T) = 8 mL/kg or high tidal volume V(T) = 16 mL/kg and a positive end-expiratory pressure (PEEP) of 2 or 6 cm H(2)O. RM were performed every 5 min, 60 min or not at all. Lung mechanics were followed by the forced oscillation technique. Blood pressure (BP), electrocardiogram (ECG), heart frequency (HF), oxygen saturation and body temperature were monitored. Blood gases, neutrophil-recruitment, microvascular permeability and pro-inflammatory cytokines in bronchoalveolar lavage (BAL) and blood serum as well as histopathology of the lung were examined. RESULTS MV with repetitive RM every 5 min resulted in stable respiratory mechanics. Ventilation without RM worsened lung mechanics due to alveolar collapse, leading to impaired gas exchange. HF and BP were affected by anaesthesia, but not by ventilation. Microvascular permeability was highest in atelectatic lungs, whereas neutrophil-recruitment and structural changes were strongest in lungs ventilated with high tidal volume. The cytokines IL-6 and KC, but neither TNF nor IP-10, were elevated in the BAL and serum of all ventilated mice and were reduced by recurrent RM. Lung mechanics, oxygenation and pulmonary inflammation were improved by increased PEEP. CONCLUSIONS Recurrent RM maintain lung mechanics in their physiological range during low tidal volume ventilation of healthy mice by preventing atelectasis and reduce the development of pulmonary inflammation.
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Affiliation(s)
- Lucy Kathleen Reiss
- Institute of Pharmacology and Toxicology, Medical Faculty of RWTH Aachen University, Aachen, Germany.
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