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Rojas-Ruiz A, Boucher M, Gill R, Gélinas L, Tom FQ, Fereydoonzad L, Graham P, Soliz J, Bossé Y. Lung stiffness of C57BL/6 versus BALB/c mice. Sci Rep 2023; 13:17481. [PMID: 37838793 PMCID: PMC10576825 DOI: 10.1038/s41598-023-44797-x] [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: 06/13/2023] [Accepted: 10/12/2023] [Indexed: 10/16/2023] Open
Abstract
This study was undertaken to determine whether a smaller lung volume or a stiffer lung tissue accounts for the greater lung elastance of C57BL/6 than BALB/c mice. The mechanical properties of the respiratory system and lung volumes were measured with the flexiVent and compared between male C57BL/6 and BALB/c mice (n = 9). The size of the excised lung was also measured by volume liquid displacement. One lobe was then subjected to sinusoidal strains in vitro to directly assess the mechanical properties of the lung tissue, and another one was used to quantify the content of hydroxyproline. In vivo elastance was markedly greater in C57BL/6 than BALB/c mice based on 5 different readouts. For example, respiratory system elastance was 24.5 ± 1.7 vs. 21.5 ± 2.4 cmH2O/mL in C57BL/6 and BALB/c mice, respectively (p = 0.007). This was not due to a different lung volume measured by displaced liquid volume. On the isolated lobes, both elastance and the hydroxyproline content were significantly greater in C57BL/6 than BALB/c mice. These results suggest that the lung elastance of C57BL/6 mice is greater than BALB/c mice not because of a smaller lung volume but because of a stiffer lung tissue due to a greater content of collagen.
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Affiliation(s)
- Andrés Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Rebecka Gill
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Louis Gélinas
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Fun-Qun Tom
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | | | | | - Jorge Soliz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, Pavillon A, room 2089, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada.
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Pybus HJ, O'Dea RD, Brook BS. A dynamical model of TGF-β activation in asthmatic airways. MATHEMATICAL MEDICINE AND BIOLOGY : A JOURNAL OF THE IMA 2023; 40:238-265. [PMID: 37285178 DOI: 10.1093/imammb/dqad004] [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: 09/20/2021] [Revised: 05/30/2023] [Accepted: 06/05/2023] [Indexed: 06/08/2023]
Abstract
Excessive activation of the regulatory cytokine transforming growth factor $\beta $ (TGF-$\beta $) via contraction of airway smooth muscle (ASM) is associated with the development of asthma. In this study, we develop an ordinary differential equation model that describes the change in density of the key airway wall constituents, ASM and extracellular matrix (ECM), and their interplay with subcellular signalling pathways leading to the activation of TGF-$\beta $. We identify bistable parameter regimes where there are two positive steady states, corresponding to either reduced or elevated TGF-$\beta $ concentration, with the latter leading additionally to increased ASM and ECM density. We associate the former with a healthy homeostatic state and the latter with a diseased (asthmatic) state. We demonstrate that external stimuli, inducing TGF-$\beta $ activation via ASM contraction (mimicking an asthmatic exacerbation), can perturb the system irreversibly from the healthy state to the diseased one. We show that the properties of the stimuli, such as their frequency or strength, and the clearance of surplus active TGF-$\beta $, are important in determining the long-term dynamics and the development of disease. Finally, we demonstrate the utility of this model in investigating temporal responses to bronchial thermoplasty, a therapeutic intervention in which ASM is ablated by applying thermal energy to the airway wall. The model predicts the parameter-dependent threshold damage required to obtain irreversible reduction in ASM content, suggesting that certain asthma phenotypes are more likely to benefit from this intervention.
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Affiliation(s)
- Hannah J Pybus
- Department of Bioengineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Reuben D O'Dea
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Bindi S Brook
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Gill R, Rojas‐Ruiz A, Boucher M, Henry C, Bossé Y. More airway smooth muscle in males versus females in a mouse model of asthma: A blessing in disguise? Exp Physiol 2023; 108:1080-1091. [PMID: 37341687 PMCID: PMC10988431 DOI: 10.1113/ep091236] [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: 03/30/2023] [Accepted: 06/06/2023] [Indexed: 06/22/2023]
Abstract
NEW FINDINGS What is the central question of this study? The lung response to inhaled methacholine is reputed to be greater in male than in female mice. The underpinnings of this sex disparity are ill defined. What is the main finding and its importance? We demonstrated that male airways exhibit a greater content of airway smooth muscle than female airways. We also found that, although a more muscular airway tree in males might contribute to their greater responsiveness to inhaled methacholine than females, it might also curb the heterogeneity in small airway narrowing. ABSTRACT Mouse models are helpful in unveiling the mechanisms underlying sex disparities in asthma. In comparison to their female counterparts, male mice are hyperresponsive to inhaled methacholine, a cardinal feature of asthma that contributes to its symptoms. The physiological details and the structural underpinnings of this hyperresponsiveness in males are currently unknown. Herein, BALB/c mice were exposed intranasally to either saline or house dust mite once daily for 10 consecutive days to induce experimental asthma. Twenty-four hours after the last exposure, respiratory mechanics were measured at baseline and after a single dose of inhaled methacholine that was adjusted to trigger the same degree of bronchoconstriction in both sexes (it was twice as high in females). Bronchoalveolar lavages were then collected, and the lungs were processed for histology. House dust mite increased the number of inflammatory cells in bronchoalveolar lavages to the same extent in both sexes (asthma, P = 0.0005; sex, P = 0.96). The methacholine response was also markedly increased by asthma in both sexes (e.g., P = 0.0002 for asthma on the methacholine-induced bronchoconstriction). However, for a well-matched bronchoconstriction between sexes, the increase in hysteresivity, an indicator of airway narrowing heterogeneity, was attenuated in males for both control and asthmatic mice (sex, P = 0.002). The content of airway smooth muscle was not affected by asthma but was greater in males (asthma, P = 0.31; sex, P < 0.0001). These results provide further insights regarding an important sex disparity in mouse models of asthma. The increased amount of airway smooth muscle in males might contribute functionally to their greater methacholine response and, possibly, to their decreased propensity for airway narrowing heterogeneity.
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Affiliation(s)
- Rebecka Gill
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Andrés Rojas‐Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université LavalDépartement de médecineQuébecCanada
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Kawano T, Zhou J, Anwar S, Salah H, Dayal AH, Ishikawa Y, Boetel K, Takahashi T, Sharma K, Inoue M. T cell infiltration into the brain triggers pulmonary dysfunction in murine Cryptococcus-associated IRIS. Nat Commun 2023; 14:3831. [PMID: 37380639 DOI: 10.1038/s41467-023-39518-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 06/16/2023] [Indexed: 06/30/2023] Open
Abstract
Cryptococcus-associated immune reconstitution inflammatory syndrome (C-IRIS) is a condition frequently occurring in immunocompromised patients receiving antiretroviral therapy. C-IRIS patients exhibit many critical symptoms, including pulmonary distress, potentially complicating the progression and recovery from this condition. Here, utilizing our previously established mouse model of unmasking C-IRIS (CnH99 preinfection and adoptive transfer of CD4+ T cells), we demonstrated that pulmonary dysfunction associated with the C-IRIS condition in mice could be attributed to the infiltration of CD4+ T cells into the brain via the CCL8-CCR5 axis, which triggers the nucleus tractus solitarius (NTS) neuronal damage and neuronal disconnection via upregulated ephrin B3 and semaphorin 6B in CD4+ T cells. Our findings provide unique insight into the mechanism behind pulmonary dysfunction in C-IRIS and nominate potential therapeutic targets for treatment.
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Affiliation(s)
- Tasuku Kawano
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- Division of Pathophysiology, Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima Aoba-Ku, Sendai, Miyagi, 981-8558, Japan
| | - Jinyan Zhou
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- Neuroscience Program, The University of Illinois at Urbana-Champaign, 405 North Matthews Avenue, Urbana, IL, 61801, USA
| | - Shehata Anwar
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- Department of Pathology, Faculty of Veterinary Medicine, Beni-Suef University (BSU), Beni-Suef, 62511, Egypt
| | - Haneen Salah
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- School of Molecular and Cell Biology, The University of Illinois at Urbana-Champaign, 407 South Goodwin Avenue, Urbana, IL, 61801, USA
| | - Andrea H Dayal
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- School of Molecular and Cell Biology, The University of Illinois at Urbana-Champaign, 407 South Goodwin Avenue, Urbana, IL, 61801, USA
| | - Yuzuki Ishikawa
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- School of Molecular and Cell Biology, The University of Illinois at Urbana-Champaign, 407 South Goodwin Avenue, Urbana, IL, 61801, USA
| | - Katelyn Boetel
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
- School of Molecular and Cell Biology, The University of Illinois at Urbana-Champaign, 407 South Goodwin Avenue, Urbana, IL, 61801, USA
| | - Tomoko Takahashi
- Division of Pathophysiology, Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima Aoba-Ku, Sendai, Miyagi, 981-8558, Japan
| | - Kamal Sharma
- Department of Anatomy and Cell Biology, University of Illinois, Chicago, 808 S. Wood Street, Chicago, IL, 60612, USA
| | - Makoto Inoue
- Department of Comparative Biosciences, The University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA.
- Neuroscience Program, The University of Illinois at Urbana-Champaign, 405 North Matthews Avenue, Urbana, IL, 61801, USA.
- Beckman Institute for Advanced Science and Technology, 405 North Matthews Avenue, Urbana, IL, 61801, USA.
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Sallé-Lefort S, Miard S, Henry C, Arias-Reyes C, Marcouiller F, Beaulieu MJ, Aubin S, Lechasseur A, Jubinville É, Marsolais D, Morissette MC, Joseph V, Soliz J, Bossé Y, Picard F. Malat1 deficiency prevents hypoxia-induced lung dysfunction by protecting the access to alveoli. Front Physiol 2022; 13:949378. [PMID: 36105289 PMCID: PMC9464821 DOI: 10.3389/fphys.2022.949378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/02/2022] [Indexed: 12/02/2022] Open
Abstract
Hypoxia is common in lung diseases and a potent stimulator of the long non-coding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1). Herein, we investigated the impact of Malat1 on hypoxia-induced lung dysfunction in mice. Malat1-deficient mice and their wild-type littermates were tested after 8 days of normoxia or hypoxia (10% oxygen). Hypoxia decreased elastance of the lung by increasing lung volume and caused in vivo hyperresponsiveness to methacholine without altering the contraction of airway smooth muscle. Malat1 deficiency also modestly decreased lung elastance but only when tested at low lung volumes and without altering lung volume and airway smooth muscle contraction. The in vivo responsiveness to methacholine was also attenuated by Malat1 deficiency, at least when elastance, a readout sensitive to small airway closure, was used to assess the response. More impressively, in vivo hyperresponsiveness to methacholine caused by hypoxia was virtually absent in Malat1-deficient mice, especially when hysteresivity, a readout sensitive to small airway narrowing heterogeneity, was used to assess the response. Malat1 deficiency also increased the coefficient of oxygen extraction and decreased ventilation in conscious mice, suggesting improvements in gas exchange and in clinical signs of respiratory distress during natural breathing. Combined with a lower elastance at low lung volumes at baseline, as well as a decreased propensity for small airway closure and narrowing heterogeneity during a methacholine challenge, these findings represent compelling evidence suggesting that the lack of Malat1 protects the access to alveoli for air entering the lung.
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Affiliation(s)
- Sandrine Sallé-Lefort
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Pharmacy, Université Laval, Quebec, QC, Canada
| | - Stéphanie Miard
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Cyndi Henry
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Christian Arias-Reyes
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - François Marcouiller
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Marie-Josée Beaulieu
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Sophie Aubin
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Ariane Lechasseur
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Éric Jubinville
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - David Marsolais
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Mathieu C. Morissette
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Vincent Joseph
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Jorge Soliz
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
| | - Ynuk Bossé
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Medicine, Université Laval, Quebec, QC, Canada
- *Correspondence: Ynuk Bossé, ; Frédéric Picard,
| | - Frédéric Picard
- Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Faculty of Pharmacy, Université Laval, Quebec, QC, Canada
- *Correspondence: Ynuk Bossé, ; Frédéric Picard,
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Boucher M, Dufour-Mailhot A, Tremblay-Pitre S, Khadangi F, Rojas-Ruiz A, Henry C, Bossé Y. In mice of both sexes, repeated contractions of smooth muscle in vivo greatly enhance the response of peripheral airways to methacholine. Respir Physiol Neurobiol 2022; 304:103938. [PMID: 35716869 DOI: 10.1016/j.resp.2022.103938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/10/2022] [Accepted: 06/12/2022] [Indexed: 10/18/2022]
Abstract
BALB/c mice from both sexes underwent one of two nebulized methacholine challenges that were preceded by a period of 20 min either with or without tone induced by repeated contractions of the airway smooth muscle. Impedance was monitored throughout and the constant phase model was used to dissociate the impact of tone on conducting airways (RN - Newtonian resistance) versus the lung periphery (G and H - tissue resistance and elastance). The effect of tone on smooth muscle contractility was also tested on excised tracheas. While tone markedly potentiated the methacholine-induced gains in H and G in both sexes, the gain in RN was only potentiated in males. The contractility of female and male tracheas was also potentiated by tone. Inversely, the methacholine-induced gain in hysteresivity (G/H) was mitigated by tone in both sexes. Therefore, the tone-induced muscle hypercontractility impacts predominantly the lung periphery in vivo, but also promotes further airway narrowing in males while protecting against narrowing heterogeneity in both sexes.
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Affiliation(s)
- Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Alexis Dufour-Mailhot
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Sophie Tremblay-Pitre
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Andrés Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada.
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Khadangi F, Tremblay-Pitre S, Dufour-Mailhot A, Rojas-Ruiz AB, Boucher M, Henry C, Fereydoonzad L, Brunet D, Robichaud A, Bossé Y. Sensitive physiological readouts to evaluate countermeasures for lipopolysaccharide-induced lung alterations in mice. Am J Physiol Lung Cell Mol Physiol 2022; 323:L107-L120. [PMID: 35670484 DOI: 10.1152/ajplung.00073.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite decades of research, studies investigating the physiological alterations caused by an acute bout of inflammation induced by exposing the lung to lipopolysaccharide have yielded inconsistent results. This can be attributed to small effects and/or a lack of fitted physiological testing. Herein, a comprehensive investigation of lung mechanics was conducted in 270 male C57BL/6 mice at 24, 48 or 96 h after an intranasal exposure to saline or lipopolysaccharide at either 1 or 3 mg/kg (30 mice per group). Traditional techniques that probe the lung using small-amplitude perturbations (i.e., oscillometry) were used, together with less conventional and new techniques that probe the lung using maneuvers of large amplitudes. The latter include a partial and a full-range pressure-volume maneuvers to measure quasi-static elastance, compliance, total lung volume, vital capacity and residual volume. The results demonstrate that lung mechanics assessed by oscillometry was only slightly affected by lipopolysaccharide, confirming previous findings. In contradistinction, lipopolysaccharide markedly altered mechanics when the lung was probed with maneuvers of large amplitudes. With the dose of 3 mg/kg at the peak of inflammation (48 h post-exposure), lipopolysaccharide increased quasi-static elastance by 26.7% (p<0.0001), and decreased compliance by 34.5% (p<0.0001). It also decreased lung volumes, including total lung capacity, vital capacity and residual volume by 33.3%, 30.5% and 43.3%, respectively (all p<0.0001). These newly reported physiological alterations represent sensitive outcomes to efficiently evaluate countermeasures (e.g., drugs) in the context of several lung diseases.
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Affiliation(s)
- Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
| | - Sophie Tremblay-Pitre
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
| | - Alexis Dufour-Mailhot
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
| | - Andrés Bruno Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
| | | | - David Brunet
- SCIREQ - Scientific Respiratory Equipment Inc., Montreal, Canada
| | | | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Québec, Canada
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Ganouna-Cohen G, Khadangi F, Marcouiller F, Bossé Y, Joseph V. Additive effects of orchiectomy and intermittent hypoxia on lung mechanics and inflammation in C57BL/6J male mice. Exp Physiol 2021; 107:68-81. [PMID: 34761830 DOI: 10.1113/ep090050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/05/2021] [Indexed: 01/01/2023]
Abstract
NEW FINDINGS What is the central question of this study? Does endogenous testosterone modulate the consequences of intermittent hypoxia (IH) in the lungs of male mice? What is the main finding and its importance? Orchiectomized mice exposed to IH develop a pattern that is similar to emphysema or obstructive lung disease with elevated lung volumes, low pulmonary elastance during a methacholine challenge test and high counts of lymphocytes in bronchoalveolar lavages. Since low testosterone levels and other respiratory diseases are common in sleep apnoea, there is a clear clinical relevance to these results. ABSTRACT We tested the hypothesis that low testosterone levels modulate the pulmonary responses to intermittent hypoxia (IH; used as a model of sleep apnoea (SA)) in male mice. We used intact (SHAM) or orchiectomized (ORX) mice exposed to IH for 14 days (12 h/day, 10 cycles/h, 6% oxygen) or to normoxia (Nx). We first measured ventilation and metabolic rates in freely behaving mice (whole-body plethysmography) and then respiratory mechanics in tracheotomized mice (flexiVent). We assessed the respiratory system resistance and elastance (Ers ), Newtonian resistance (resistance of the large airways), tissue damping and tissue elastance (H) under baseline conditions and during a methacholine challenge test. We also measured the quasi-static compliance and inspiratory capacity with partial pressure-volume loops. Finally, inflammatory cells were counted in the broncho-alveolar lavage (BAL) and we measured lung volume by water displacement. ORX-IH mice had higher tidal volume, inspiratory capacity and lung volume compared to the other groups, but showed signs of low efficiency of O2 exchange rate relative to minute ventilation. During the methacholine challenge, orchiectomy decreased the values of most mechanical parameters and IH reduced Ers and H leading to very low values in ORX-IH mice. Finally, the total number of cells and the number of lymphocytes in BAL were both increased by IH in ORX mice. Since reduced lung elasticity, low O2 extraction, increased lung volumes and inflammation are signs of emphysematous lung disease, we conclude that testosterone might prevent lung emphysema during IH exposures.
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Affiliation(s)
- Gauthier Ganouna-Cohen
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - Fatemeh Khadangi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - François Marcouiller
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - Ynuk Bossé
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - Vincent Joseph
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
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9
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Khadangi F, Forgues AS, Tremblay-Pitre S, Dufour-Mailhot A, Henry C, Boucher M, Beaulieu MJ, Morissette M, Fereydoonzad L, Brunet D, Robichaud A, Bossé Y. Intranasal versus intratracheal exposure to lipopolysaccharides in a murine model of acute respiratory distress syndrome. Sci Rep 2021; 11:7777. [PMID: 33833346 PMCID: PMC8032690 DOI: 10.1038/s41598-021-87462-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/22/2021] [Indexed: 12/11/2022] Open
Abstract
Due to frequent and often severe lung affections caused by COVID-19, murine models of acute respiratory distress syndrome (ARDS) are increasingly used in experimental lung research. The one induced by a single lipopolysaccharide (LPS) exposure is practical. However, whether it is preferable to administer LPS intranasally or intratracheally remains an open question. Herein, female C57Bl/6 J mice were exposed intranasally or intratracheally to one dose of either saline or 3 mg/kg of LPS. They were studied 24 h later. The groups treated with LPS, either intranasally or intratracheally, exhibited a pronounced neutrophilic inflammation, signs of lung tissue damage and protein extravasation into the alveoli, and mild lung dysfunction. The magnitude of the response was generally not different between groups exposed intranasally versus intratracheally. However, the variability of some the responses was smaller in the LPS-treated groups exposed intranasally versus intratracheally. Notably, the saline-treated mice exposed intratracheally demonstrated a mild neutrophilic inflammation and alterations of the airway epithelium. We conclude that an intranasal exposure is as effective as an intratracheal exposure in a murine model of ARDS induced by LPS. Additionally, the groups exposed intranasally demonstrated less variability in the responses to LPS and less complications associated with the sham procedure.
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Affiliation(s)
- Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Anne-Sophie Forgues
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Sophie Tremblay-Pitre
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Alexis Dufour-Mailhot
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Marie-Josée Beaulieu
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Mathieu Morissette
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | | | - David Brunet
- SCIREQ - Scientific Respiratory Equipment Inc., Montreal, Canada
| | | | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Pavillon Mallet, M2694, 2725, chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada.
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10
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Lundblad LKA, Robichaud A. Oscillometry of the respiratory system: a translational opportunity not to be missed. Am J Physiol Lung Cell Mol Physiol 2021; 320:L1038-L1056. [PMID: 33822645 PMCID: PMC8203417 DOI: 10.1152/ajplung.00222.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Airway oscillometry has become the de facto standard for quality assessment of lung physiology in laboratory animals and has demonstrated its usefulness in understanding diseases of small airways. Nowadays, it is seeing extensive use in daily clinical practice and research; however, a question that remains unanswered is how well physiological findings in animals and humans correlate? Methodological and device differences are obvious between animal and human studies. However, all devices deliver an oscillated airflow test signal and output respiratory impedance. In addition, despite analysis differences, there are ways to interpret animal and human oscillometry data to allow suitable comparisons. The potential with oscillometry is its ability to reveal universal features of the respiratory system across species, making translational extrapolation likely to be predictive. This means that oscillometry can thus help determine if an animal model displays the same physiological characteristics as the human disease. Perhaps more importantly, it can also be useful to determine whether an intervention is effective as well as to understand if it affects the desired region of the respiratory system, e.g., the periphery of the lung. Finally, findings in humans can also inform preclinical scientists and give indications as to what type of physiological changes should be observed in animal models to make them relevant as models of human disease. The present article will attempt to demonstrate the potential of oscillometry in respiratory research, an area where the development of novel therapies is plagued with a failure rate higher than in other disease areas.
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Affiliation(s)
- Lennart K A Lundblad
- Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.,THORASYS Thoracic Medical Systems Inc., Montreal, Quebec, Canada
| | - Annette Robichaud
- SCIREQ Scientific Respiratory Equipment Inc., Montreal, Quebec, Canada
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11
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Zahn N, Mikulsky BN, Roni MSR, Yocum GT, Mian MY, Knutson DE, Cook JM, Emala CW, Stafford DC, Arnold LA. Nebulized MIDD0301 Reduces Airway Hyperresponsiveness in Moderate and Severe Murine Asthma Models. ACS Pharmacol Transl Sci 2020; 3:1381-1390. [PMID: 33344908 PMCID: PMC7737320 DOI: 10.1021/acsptsci.0c00180] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 01/19/2023]
Abstract
We report the relaxation of methacholine-constricted airways with nebulized MIDD0301, a positive allosteric γ-aminobutyric acid type A receptor (GABAAR) modulator. The therapeutic efficacy of nebulized MIDD0301 in reducing airway resistance was investigated in spontaneous breathing mice using a whole-body plethysmograph and in unconscious mice using a forced oscillation technique. Prophylactic nebulized MIDD0301 reduced subsequent methacholine-induced bronchoconstriction in ovalbumin and house dust mite allergic asthma models and in normal mice. Nebulized MIDD0301 exhibited comparable or better therapeutic potency compared to nebulized albuterol and oral montelukast. Prophylactic nebulized MIDD0301 was also effective in reducing bronchoconstriction, comparable to nebulized albuterol or fluticasone, in a steroid resistant asthma mouse model induced by intratracheal installation of lipopolysaccharide and interferon-gamma. Oral dexamethasone was ineffective in this model. Nebulized MIDD0301 was also effective in reversing bronchospasm when dosed after methacholine challenge comparable to albuterol. Pharmacokinetic studies showed that about 0.06% of nebulized MIDD0301 entered the mouse lung when using a whole body plethysmograph and therapeutic levels were sustained in the lung for at least 25 min. Consistent with previous reports on orally dosed MIDD0301, high doses of nebulized MIDD0301 resulted in minimal brain exposure and thus no observable adverse sensorimotor or respiratory depression effects occurred. In addition, no adverse cardiovascular effects were observed following 100 mg/kg i.p. dosing. These results further demonstrate that charged imidazodiazepine MIDD0301 can selectively target lung GABAAR without adverse motor, cardiovascular, or respiratory effects and inhaled dosing is effective in reducing bronchoconstriction in allergen and infectious lung inflammation.
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Affiliation(s)
- Nicolas
M. Zahn
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | | | - M. S. Rashid Roni
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - Gene T. Yocum
- Department
of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
| | - Md Yeunus Mian
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - Daniel E. Knutson
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - James M. Cook
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - Charles W. Emala
- Department
of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
| | - Douglas C. Stafford
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States,Pantherics
Incorporated, La Jolla, California 92037, United States
| | - Leggy A. Arnold
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States,Pantherics
Incorporated, La Jolla, California 92037, United States,
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12
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O'Sullivan MJ, Phung TKN, Park JA. Bronchoconstriction: a potential missing link in airway remodelling. Open Biol 2020; 10:200254. [PMID: 33259745 PMCID: PMC7776576 DOI: 10.1098/rsob.200254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/10/2020] [Indexed: 02/06/2023] Open
Abstract
In asthma, progressive structural changes of the airway wall are collectively termed airway remodelling. Despite its deleterious effect on lung function, airway remodelling is incompletely understood. As one of the important causes leading to airway remodelling, here we discuss the significance of mechanical forces that are produced in the narrowed airway during asthma exacerbation, as a driving force of airway remodelling. We cover in vitro, ex vivo and in vivo work in this field, and discuss up-to-date literature supporting the idea that bronchoconstriction may be the missing link in a comprehensive understanding of airway remodelling in asthma.
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Affiliation(s)
| | | | - Jin-Ah Park
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, USA
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13
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Veerati PC, Mitchel JA, Reid AT, Knight DA, Bartlett NW, Park JA, Grainge CL. Airway mechanical compression: its role in asthma pathogenesis and progression. Eur Respir Rev 2020; 29:190123. [PMID: 32759373 PMCID: PMC8008491 DOI: 10.1183/16000617.0123-2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/30/2020] [Indexed: 12/22/2022] Open
Abstract
The lung is a mechanically active organ, but uncontrolled or excessive mechanical forces disrupt normal lung function and can contribute to the development of disease. In asthma, bronchoconstriction leads to airway narrowing and airway wall buckling. A growing body of evidence suggests that pathological mechanical forces induced by airway buckling alone can perpetuate disease processes in asthma. Here, we review the data obtained from a variety of experimental models, including in vitro, ex vivo and in vivo approaches, which have been used to study the impact of mechanical forces in asthma pathogenesis. We review the evidence showing that mechanical compression alters the biological and biophysical properties of the airway epithelium, including activation of the epidermal growth factor receptor pathway, overproduction of asthma-associated mediators, goblet cell hyperplasia, and a phase transition of epithelium from a static jammed phase to a mobile unjammed phase. We also define questions regarding the impact of mechanical forces on the pathology of asthma, with a focus on known triggers of asthma exacerbations such as viral infection.
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Affiliation(s)
- Punnam Chander Veerati
- School of Medicine and Public Health, University of Newcastle, Callaghan, Australia
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, New Lambton Heights, Australia
| | - Jennifer A Mitchel
- Molecular and Integrative Physiological Sciences Program, Dept of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Andrew T Reid
- School of Medicine and Public Health, University of Newcastle, Callaghan, Australia
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, New Lambton Heights, Australia
| | - Darryl A Knight
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, New Lambton Heights, Australia
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, Australia
- Dept of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada
- Research and Academic Affairs, Providence Health Care Research Institute, Vancouver, Canada
| | - Nathan W Bartlett
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, New Lambton Heights, Australia
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, Australia
| | - Jin-Ah Park
- Molecular and Integrative Physiological Sciences Program, Dept of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Chris L Grainge
- School of Medicine and Public Health, University of Newcastle, Callaghan, Australia
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, New Lambton Heights, Australia
- Dept of Respiratory and Sleep Medicine, John Hunter Hospital, Newcastle, Australia
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14
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Liao YSJ, Collins EN, Guevara MV, Schurmann V, Atanasova KR, Bravo L, Sponchiado M, Hoegger MJ, Reznikov LR. Airway cholinergic history modifies mucus secretion properties to subsequent cholinergic challenge in diminished chloride and bicarbonate conditions. Exp Physiol 2020; 105:1673-1683. [PMID: 32735372 DOI: 10.1113/ep088900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 07/30/2020] [Indexed: 12/25/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the impact of airway cholinergic history on the properties of airway mucus secretion in a cystic fibrosis-like environment? What is the main finding and its importance? Prior cholinergic challenge slightly modifies the characteristics of mucus secretion in response to a second cholinergic challenge in a diminished bicarbonate and chloride transport environment. Such modifications might lead to retention of mucus on the airway surface, thereby potentiating exacerbations of airway disease. ABSTRACT Viral infections precipitate exacerbations in many airway diseases, including asthma and cystic fibrosis. Although viral infections increase cholinergic transmission, few studies have examined how cholinergic history modifies subsequent cholinergic responses in the airway. In our previous work, we found that airway resistance in response to a second cholinergic challenge was increased in young pigs with a history of airway cholinergic stimulation. Given that mucus secretion is regulated by the cholinergic nervous system and that abnormal airway mucus contributes to exacerbations of airway disease, we hypothesized that prior cholinergic challenge would also modify subsequent mucus responses to a secondary cholinergic challenge. Using our established cholinergic challenge-rechallenge model in pigs, we atomized the cholinergic agonist bethanechol or saline control to pig airways. Forty-eight hours later, we removed tracheas and measured mucus secretion properties in response to a second cholinergic stimulation. The second cholinergic stimulation was conducted in conditions of diminished chloride and bicarbonate transport to mimic a cystic fibrosis-like environment. In pigs previously challenged with bethanechol, a second cholinergic stimulation produced a mild increase in sheet-like mucus films; these films were scarcely observed in animals originally challenged with saline control. The subtle increase in mucus films was not associated with changes in mucociliary transport. These data suggest that prior cholinergic history might modify mucus secretion characteristics with subsequent stimulation in certain environmental conditions or disease states. Such modifications and/or more repetitive stimulation might lead to retention of mucus on the airway surface, thereby potentiating exacerbations of airway disease.
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Affiliation(s)
- Yan Shin J Liao
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Emily N Collins
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | | | - Veronica Schurmann
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Kalina R Atanasova
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Laura Bravo
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Mariana Sponchiado
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Mark J Hoegger
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Leah R Reznikov
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
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15
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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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16
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Anthracopoulos MB, Everard ML. Asthma: A Loss of Post-natal Homeostatic Control of Airways Smooth Muscle With Regression Toward a Pre-natal State. Front Pediatr 2020; 8:95. [PMID: 32373557 PMCID: PMC7176812 DOI: 10.3389/fped.2020.00095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
The defining feature of asthma is loss of normal post-natal homeostatic control of airways smooth muscle (ASM). This is the key feature that distinguishes asthma from all other forms of respiratory disease. Failure to focus on impaired ASM homeostasis largely explains our failure to find a cure and contributes to the widespread excessive morbidity associated with the condition despite the presence of effective therapies. The mechanisms responsible for destabilizing the normal tight control of ASM and hence airways caliber in post-natal life are unknown but it is clear that atopic inflammation is neither necessary nor sufficient. Loss of homeostasis results in excessive ASM contraction which, in those with poor control, is manifest by variations in airflow resistance over short periods of time. During viral exacerbations, the ability to respond to bronchodilators is partially or almost completely lost, resulting in ASM being "locked down" in a contracted state. Corticosteroids appear to restore normal or near normal homeostasis in those with poor control and restore bronchodilator responsiveness during exacerbations. The mechanism of action of corticosteroids is unknown and the assumption that their action is solely due to "anti-inflammatory" effects needs to be challenged. ASM, in evolutionary terms, dates to the earliest land dwelling creatures that required muscle to empty primitive lungs. ASM appears very early in embryonic development and active peristalsis is essential for the formation of the lungs. However, in post-natal life its only role appears to be to maintain airways in a configuration that minimizes resistance to airflow and dead space. In health, significant constriction is actively prevented, presumably through classic negative feedback loops. Disruption of this robust homeostatic control can develop at any age and results in asthma. In order to develop a cure, we need to move from our current focus on immunology and inflammatory pathways to work that will lead to an understanding of the mechanisms that contribute to ASM stability in health and how this is disrupted to cause asthma. This requires a radical change in the focus of most of "asthma research."
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Affiliation(s)
| | - Mark L. Everard
- Division of Paediatrics & Child Health, Perth Children's Hospital, University of Western Australia, Perth, WA, Australia
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17
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Cazzola M, Puxeddu E, Matera MG, Rogliani P. A potential role of triple therapy for asthma patients. Expert Rev Respir Med 2019; 13:1079-1085. [PMID: 31422716 DOI: 10.1080/17476348.2019.1657408] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Introduction: The use of LAMAs in asthma is now supported by pharmacological and clinical evidence, whereas the effectiveness of therapy with ICS/LABA/LAMA fixed dose combinations in patients with asthma still remains to be determined. Areas covered: The pharmacological rationale that explains why it is possible to use triple therapy in asthma and the results of clinical studies that have explored the effects of this therapy in asthmatics is critically examined. A systematic search was conducted on 10 August 2019, and included six electronic databases: EMBASE, MEDLINE, Scopus, The Cochrane Library, Web of Science, and Google Scholar. Expert opinion: The real role of single inhaler triple therapy in asthma will be demonstrated when the various trials that are currently ongoing or are scheduled will be completed. We believe that it is appropriate to treat with triple therapy asthmatic patients who have smoked and remain symptomatic or suffer from frequent exacerbations despite initial inhaler therapy with ICS/LABA. However, we must establish when to step up or mainly step down triple therapy especially in patients who are well controlled, and what will be the cost of these combinations in the management of asthma.
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Affiliation(s)
- Mario Cazzola
- Unit of Respiratory Medicine, Department of Experimental Medicine, University of Rome "Tor Vergata" , Rome , Italy
| | - Ermanno Puxeddu
- Unit of Respiratory Medicine, Department of Experimental Medicine, University of Rome "Tor Vergata" , Rome , Italy
| | - Maria Gabriella Matera
- Unit of Pharmacology, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli" , Naples , Italy
| | - Paola Rogliani
- Unit of Respiratory Medicine, Department of Experimental Medicine, University of Rome "Tor Vergata" , Rome , Italy
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18
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Südy R, Fodor GH, Dos Santos Rocha A, Schranc Á, Tolnai J, Habre W, Peták F. Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits. J Appl Physiol (1985) 2019; 127:198-204. [PMID: 31161880 DOI: 10.1152/japplphysiol.00048.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Changes in lung mechanics are frequently inferred from intact-chest measures of total respiratory system mechanics without consideration of the chest wall contribution. The participation of lungs and chest wall in respiratory mechanics has not been evaluated systematically in small animals commonly used in respiratory research. Thus, we compared these contributions in intact-chest mice, rats, and rabbits and further characterized the influence of positive end-expiratory pressure (PEEP). Forced oscillation technique was applied to anesthetized mechanically ventilated healthy animals to obtain total respiratory system impedance (Zrs) at 0, 3, and 6 cmH2O PEEP levels. Esophageal pressure was measured by a catheter-tip micromanometer to separate Zrs into pulmonary (ZL) and chest wall (Zcw) components. A model containing a frequency-independent Newtonian resistance (RN), inertance, and a constant-phase tissue damping (G) and elastance (H) was fitted to Zrs, ZL, and Zcw spectra. The contribution of Zcw to RN was negligible in all species and PEEP levels studied. However, the participation of Zcw in G and H was significant in all species and increased significantly with increasing PEEP and animal size (rabbit > rat > mice). Even in mice, the chest wall contribution to G and H was still considerable, reaching 47.0 ± 4.0(SE)% and 32.9 ± 5.9% for G and H, respectively. These findings demonstrate that airway parameters can be assessed from respiratory system mechanical measurements. However, the contribution from the chest wall should be considered when intact-chest measurements are used to estimate lung parenchymal mechanics in small laboratory models (even in mice), particularly at elevated PEEP levels. NEW & NOTEWORTHY In species commonly used in respiratory research (rabbits, rats, mice), esophageal pressure-based estimates revealed negligible contribution from the chest wall to the Newtonian resistance. Conversely, chest wall participation in the viscoelastic tissue mechanical parameters increased with body size (rabbit > rat > mice) and positive end-expiratory pressure, with contribution varying between 30 and 50%, even in mice. These findings demonstrate the potential biasing effects of the chest wall when lung tissue mechanics are inferred from intact-chest measurements in small laboratory animals.
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Affiliation(s)
- Roberta Südy
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland.,Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
| | - Gergely H Fodor
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland
| | - André Dos Santos Rocha
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
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19
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O'Sullivan MJ, Lan B. The Aftermath of Bronchoconstriction. ACTA ACUST UNITED AC 2019; 2:0108031-108036. [PMID: 32328569 DOI: 10.1115/1.4042318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 10/30/2018] [Indexed: 11/08/2022]
Abstract
Asthma is characterized by chronic airway inflammation, airway remodeling, and excessive constriction of the airway. Detailed investigation exploring inflammation and the role of immune cells has revealed a variety of possible mechanisms by which chronic inflammation drives asthma development. However, the underlying mechanisms of asthma pathogenesis still remain poorly understood. New evidence now suggests that mechanical stimuli that arise during bronchoconstriction may play a critical role in asthma development. In this article, we review the mechanical effect of bronchoconstriction and how these mechanical stresses contribute to airway remodeling independent of inflammation.
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Affiliation(s)
- Michael J O'Sullivan
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, 665 Huntington Avenue, 1-G07, Boston, MA 02115
| | - Bo Lan
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, 665 Huntington Avenue, 1-G07, Boston, MA 02115 e-mail:
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20
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Gosens R, Gross N. The mode of action of anticholinergics in asthma. Eur Respir J 2018; 52:13993003.01247-2017. [PMID: 30115613 PMCID: PMC6340638 DOI: 10.1183/13993003.01247-2017] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 08/09/2018] [Indexed: 01/25/2023]
Abstract
Acetylcholine binds to muscarinic receptors to play a key role in the pathophysiology of asthma, leading to bronchoconstriction, increased mucus secretion, inflammation and airway remodelling. Anticholinergics are muscarinic receptor antagonists that are used in the treatment of chronic obstructive pulmonary disease and asthma. Recent in vivo and in vitro data have increased our understanding of how acetylcholine contributes to the disease manifestations of asthma, as well as elucidating the mechanism of action of anticholinergics. This review assesses the latest literature on acetylcholine in asthma pathophysiology, with a closer look at its role in airway inflammation and remodelling. New insights into the mechanism of action of anticholinergics, their effects on airway remodelling, and a review of the efficacy and safety of long-acting anticholinergics in asthma treatment will also be covered, including a summary of the latest clinical trial data. Pre-clinical data suggest that anticholinergics can reduce acetylcholine-induced airway inflammation and remodellinghttp://ow.ly/xqAQ30loP8F
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Affiliation(s)
| | - Nicholas Gross
- University Medical Research LLC, St Francis Hospital, Hartford, CT, USA
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Hill MR, Philp CJ, Billington CK, Tatler AL, Johnson SR, O'Dea RD, Brook BS. A theoretical model of inflammation- and mechanotransduction-driven asthmatic airway remodelling. Biomech Model Mechanobiol 2018; 17:1451-1470. [PMID: 29968161 PMCID: PMC6154265 DOI: 10.1007/s10237-018-1037-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 05/22/2018] [Indexed: 12/28/2022]
Abstract
Inflammation, airway hyper-responsiveness and airway remodelling are well-established hallmarks of asthma, but their inter-relationships remain elusive. In order to obtain a better understanding of their inter-dependence, we develop a mechanochemical morphoelastic model of the airway wall accounting for local volume changes in airway smooth muscle (ASM) and extracellular matrix in response to transient inflammatory or contractile agonist challenges. We use constrained mixture theory, together with a multiplicative decomposition of growth from the elastic deformation, to model the airway wall as a nonlinear fibre-reinforced elastic cylinder. Local contractile agonist drives ASM cell contraction, generating mechanical stresses in the tissue that drive further release of mitogenic mediators and contractile agonists via underlying mechanotransductive signalling pathways. Our model predictions are consistent with previously described inflammation-induced remodelling within an axisymmetric airway geometry. Additionally, our simulations reveal novel mechanotransductive feedback by which hyper-responsive airways exhibit increased remodelling, for example, via stress-induced release of pro-mitogenic and pro-contractile cytokines. Simulation results also reveal emergence of a persistent contractile tone observed in asthmatics, via either a pathological mechanotransductive feedback loop, a failure to clear agonists from the tissue, or a combination of both. Furthermore, we identify various parameter combinations that may contribute to the existence of different asthma phenotypes, and we illustrate a combination of factors which may predispose severe asthmatics to fatal bronchospasms.
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Affiliation(s)
- Michael R Hill
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Room C25, Mathematical Sciences Building, University Park, Nottingham, NG7 2RD, UK.
| | - Christopher J Philp
- Division of Respiratory Medicine, Nottingham Biomedical Research Centre, University of Nottingham, D Floor, South Block, Queen's Medical Centre Campus, Nottingham, NG7 2UH, UK
| | - Charlotte K Billington
- Division of Respiratory Medicine, Nottingham Biomedical Research Centre, University of Nottingham, D Floor, South Block, Queen's Medical Centre Campus, Nottingham, NG7 2UH, UK
| | - Amanda L Tatler
- Division of Respiratory Medicine, Nottingham Biomedical Research Centre, Nottingham City Hospital, University of Nottingham, Hucknall Road, Nottingham, NG5 1PB, UK
| | - Simon R Johnson
- Division of Respiratory Medicine, Nottingham Biomedical Research Centre, University of Nottingham, D Floor, South Block, Queen's Medical Centre Campus, Nottingham, NG7 2UH, UK
| | - Reuben D O'Dea
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Room C28, Mathematical Sciences Building, University Park, Nottingham, NG7 2RD, UK
| | - Bindi S Brook
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Room C26, Mathematical Sciences Building, University Park, Nottingham, NG7 2RD, UK
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