1
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Banerji R, Grifno GN, Shi L, Smolen D, LeBourdais R, Muhvich J, Eberman C, Hiller BE, Lee J, Regan K, Zheng S, Zhang S, Jiang J, Raslan AA, Breda JC, Pihl R, Traber K, Mazzilli S, Ligresti G, Mizgerd JP, Suki B, Nia HT. Crystal ribcage: a platform for probing real-time lung function at cellular resolution. Nat Methods 2023; 20:1790-1801. [PMID: 37710017 PMCID: PMC10860663 DOI: 10.1038/s41592-023-02004-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 08/10/2023] [Indexed: 09/16/2023]
Abstract
Understanding the dynamic pathogenesis and treatment response in pulmonary diseases requires probing the lung at cellular resolution in real time. Despite advances in intravital imaging, optical imaging of the lung during active respiration and circulation has remained challenging. Here, we introduce the crystal ribcage: a transparent ribcage that allows multiscale optical imaging of the functioning lung from whole-organ to single-cell level. It enables the modulation of lung biophysics and immunity through intravascular, intrapulmonary, intraparenchymal and optogenetic interventions, and it preserves the three-dimensional architecture, air-liquid interface, cellular diversity and respiratory-circulatory functions of the lung. Utilizing these capabilities on murine models of pulmonary pathologies we probed remodeling of respiratory-circulatory functions at the single-alveolus and capillary levels during disease progression. The crystal ribcage and its broad applications presented here will facilitate further studies of nearly any pulmonary disease as well as lead to the identification of new targets for treatment strategies.
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Affiliation(s)
- Rohin Banerji
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Gabrielle N Grifno
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Linzheng Shi
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Dylan Smolen
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Rob LeBourdais
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Johnathan Muhvich
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Cate Eberman
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Bradley E Hiller
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Jisu Lee
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Kathryn Regan
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Siyi Zheng
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Sue Zhang
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - John Jiang
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Ahmed A Raslan
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
- Department of Zoology, Faculty of Science, Assiut University, Assiut, Egypt
| | - Julia C Breda
- Section of Computational Biomedicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Riley Pihl
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Katrina Traber
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Sarah Mazzilli
- Section of Computational Biomedicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Giovanni Ligresti
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Joseph P Mizgerd
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Béla Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Hadi T Nia
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
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2
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Pereira RDD, Rabelo RAN, Oliveira NFDM, Porto SLT, Andrade ACDSP, Queiroz-Junior CM, Barbosa CLN, de Souza-Costa LP, Santos FRDS, Oliveira FBR, da Silva BLV, Umezu HL, Ferreira R, da Silva GSF, Cruz JS, Teixeira MM, Costa VV, Machado FS. A 5-Lipoxygenase Inhibitor, Zileuton, Modulates Host Immune Responses and Improves Lung Function in a Model of Severe Acute Respiratory Syndrome (SARS) Induced by Betacoronavirus. Viruses 2023; 15:2049. [PMID: 37896826 PMCID: PMC10611395 DOI: 10.3390/v15102049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
Exacerbated inflammatory responses are a hallmark of severe coronavirus disease 2019 (COVID-19). Zileuton (Zi) is a selective inhibitor of 5-lipoxygenase, an enzyme involved in the production of several inflammatory/pro-resolving lipid mediators. Herein, we investigated the effect of Zi treatment in a severe acute respiratory syndrome (SARS) model. Mouse hepatitis virus (MHV)3-infected mice treated with Zi significantly improved the clinical score, weight loss, cardiopulmonary function, and survival rates compared with infected untreated animals. The protection observed in Zi-treated mice was associated with a lower inflammatory score, reduced dendritic cell-producing tumor necrosis factor (TNF), and increased neutrophil-producing interleukin (IL)-10 in the lungs three days after infection (dpi). At 5 dpi, the lungs of treated mice showed an increase in Th2-, Treg CD4+-, and Treg CD8+-producing IL-10 and reduced Th1 infiltrating cells. Furthermore, similar results were found upon Zi treatment after SARS-CoV-2 infection in transgenic mice expressing the human angiotensin I-converting enzyme 2 (ACE2) receptor driven by the cytokeratin-18 (K18) gene promoter (K18-hACE2), significantly improving the clinical score, weight loss, and lung inflammatory score compared with untreated animals. Our data suggest that Zi protects against developing severe lung disease during SARS induced by betacoronavirus without affecting the host's capacity to deal with infection.
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Affiliation(s)
- Rafaela das Dores Pereira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Rayane Aparecida Nonato Rabelo
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Natália Fernanda de Melo Oliveira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Samuel Luiz Teixeira Porto
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Ana Claudia dos Santos Pereira Andrade
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (A.C.d.S.P.A.); (C.M.Q.-J.); (B.L.V.d.S.)
| | - Celso M. Queiroz-Junior
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (A.C.d.S.P.A.); (C.M.Q.-J.); (B.L.V.d.S.)
| | - César Luís Nascimento Barbosa
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
| | - Luiz Pedro de Souza-Costa
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Felipe Rocha da Silva Santos
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Fernando Bento Rodrigues Oliveira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Bárbara Luísa Vieira da Silva
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (A.C.d.S.P.A.); (C.M.Q.-J.); (B.L.V.d.S.)
| | - Hanna L. Umezu
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (H.L.U.); (G.S.F.d.S.)
| | - Raquel Ferreira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Glauber S. F. da Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (H.L.U.); (G.S.F.d.S.)
| | - Jader Santos Cruz
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Mauro Martins Teixeira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
| | - Vivian Vasconcelos Costa
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (A.C.d.S.P.A.); (C.M.Q.-J.); (B.L.V.d.S.)
| | - Fabiana Simão Machado
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (R.d.D.P.); (R.A.N.R.); (N.F.d.M.O.); (S.L.T.P.); (L.P.d.S.-C.); (F.R.d.S.S.); (F.B.R.O.); (R.F.); (J.S.C.); (M.M.T.)
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
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3
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Roberts JD. LungElast-an open-source, flexible, low-cost, microprocessor-controlled mouse lung elastometer. Sci Rep 2023; 13:11246. [PMID: 37438462 PMCID: PMC10338507 DOI: 10.1038/s41598-023-38310-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/06/2023] [Indexed: 07/14/2023] Open
Abstract
The study of mouse lung mechanics provides essential insights into the physiological mechanisms of pulmonary disease. Consequently, investigators assemble custom systems comprising infusion-withdrawal syringe pumps and analog pressure sensors to investigate the lung function of these animals. But these systems are expensive and require ongoing regulation, making them challenging to use. Here I introduce LungElast, an open-source, inexpensive, and self-contained instrument that can experimentally determine lung elasticity and volumes even in immature mice. It is assembled using custom 3D printed parts and readily available or easily constructed components. In this device, a microprocessor-controlled stepper motor automatically regulates lung volume by precisely driving a syringe piston whose position is determined using time-of-flight LIDAR technology. The airway pressures associated with the lung volumes are determined using compact sensor-on-chip technology, retrieved in a digital format, and stored by the microcontroller. The instrument software is modular, which eases device testing, calibration, and use. Data are also provided here that specify the accuracy and precision of the elastometer's sensors and volume delivery and demonstrate its use with lung models and mouse pups. This instrument has excellent potential for research and educational work.
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Affiliation(s)
- Jesse D Roberts
- Cardiovascular Research Center of the General Medical Services and the Departments of Anesthesia, Critical Care and Pain Medicine, Pediatrics, and Medicine, Massachusetts General Hospital - East, 149 13th St, Boston, MA, USA.
- Harvard Medical School, Harvard University, Cambridge, MA, USA.
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4
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Lefevre E, Bouilhol E, Chauvière A, Souleyreau W, Derieppe MA, Trotier AJ, Miraux S, Bikfalvi A, Ribot EJ, Nikolski M. Deep learning model for automatic segmentation of lungs and pulmonary metastasis in small animal MR images. FRONTIERS IN BIOINFORMATICS 2022; 2:999700. [PMID: 36304332 PMCID: PMC9580845 DOI: 10.3389/fbinf.2022.999700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/26/2022] [Indexed: 12/03/2022] Open
Abstract
Lungs are the most frequent site of metastases growth. The amount and size of pulmonary metastases acquired from MRI imaging data are the important criteria to assess the efficacy of new drugs in preclinical models. While efficient solutions both for MR imaging and the downstream automatic segmentation have been proposed for human patients, both MRI lung imaging and segmentation in preclinical animal models remains challenging due to the physiological motion (respiratory and cardiac movements), to the low amount of protons in this organ and to the particular challenge of precise segmentation of metastases. As a consequence post-mortem analysis is currently required to obtain information on metastatic volume. In this work, we have developed a complete methodological pipeline for automated analysis of lungs and metastases in mice, consisting of an MR sequence for image acquisition and a deep learning method for automatic segmentation of both lungs and metastases. On one hand, we optimized an MR sequence for mouse lung imaging with high contrast for high detection sensitivity. On the other hand we developed DeepMeta, a multiclass U-Net 3+ deep learning model to automatically segment the images. To assess if the proposed deep learning pipeline is able to provide an accurate segmentation of both lungs and pulmonary metastases, we have longitudinally imaged mice with fast- and slow-growing metastasis. Fifty-five balb/c mice were injected with two different derivatives of renal carcinoma cells. Mice were imaged with a SG-bSSFP (self-gated balanced steady state free precession) sequence at different time points after the injection of cancer cells. Both lung and metastases segmentations were manually performed by experts. DeepMeta was trained to perform lung and metastases segmentation based on the resulting ground truth annotations. Volumes of lungs and of pulmonary metastases as well as the number of metastases per mouse were measured on a separate test dataset of MR images. Thanks to the SG method, the 3D bSSFP images of lungs were artifact-free, enabling the downstream detection and serial follow-up of metastases. Moreover, both lungs and metastases segmentation was accurately performed by DeepMeta as soon as they reached the volume of ∼ 0.02 m m 3 . Thus we were able to distinguish two groups of mice in terms of number and volume of pulmonary metastases as well as in terms of the slow versus fast patterns of growth of metastases. We have shown that our methodology combining SG-bSSFP with deep learning, enables processing of the whole animal lungs and is thus a viable alternative to histology alone.
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Affiliation(s)
- Edgar Lefevre
- Bordeaux Bioinformatics Center, University of Bordeaux, Bordeaux, France,*Correspondence: Edgar Lefevre, ; Macha Nikolski,
| | - Emmanuel Bouilhol
- Bordeaux Bioinformatics Center, University of Bordeaux, Bordeaux, France,IBGC, CNRS, University of Bordeaux, Bordeaux, France
| | - Antoine Chauvière
- Bordeaux Bioinformatics Center, University of Bordeaux, Bordeaux, France
| | | | | | - Aurélien J. Trotier
- Centre de Résonance Magnétique des Systèmes Biologiques, CNRS, University of Bordeaux, Bordeaux, France
| | - Sylvain Miraux
- Centre de Résonance Magnétique des Systèmes Biologiques, CNRS, University of Bordeaux, Bordeaux, France
| | | | - Emeline J. Ribot
- Centre de Résonance Magnétique des Systèmes Biologiques, CNRS, University of Bordeaux, Bordeaux, France
| | - Macha Nikolski
- Bordeaux Bioinformatics Center, University of Bordeaux, Bordeaux, France,IBGC, CNRS, University of Bordeaux, Bordeaux, France,*Correspondence: Edgar Lefevre, ; Macha Nikolski,
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5
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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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6
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Robichaud A, Fereydoonzad L, Collins SL, Loube JM, Ishii Y, Horton MR, Martin JG, Mitzner W. Airway compliance measurements in mouse models of respiratory diseases. Am J Physiol Lung Cell Mol Physiol 2021; 321:L204-L212. [PMID: 34009049 DOI: 10.1152/ajplung.00470.2020] [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] [Indexed: 01/11/2023] Open
Abstract
The quantification of airway compliance (Caw) is essential to the study of airway alterations in disease models. However, the required measurements of airway pressure and volume are difficult to acquire in mice. We hypothesized that the inflation limb of full-range pressure-volume (PV) curves could be used to quantify Caw, as it contains a segment where only the airway tree is distended. The study objective was to assess the feasibility of the approach by analysis of full-range PV curves previously collected in three mouse models: an elastase model of emphysema, a genetic model spontaneously developing emphysema (leukotriene C4 synthase knockout; LTC4S-KO), and a bleomycin model of lung fibrosis. Attempts to validate results included Caw change relative to respiratory system compliance (ΔCaw/ΔC), the minute work of breathing (mWOB), and the elastance at 20.5 Hz (Ers_20.5) from prior respiratory mechanics measurements in the same subjects. Caw was estimated at 3% of total compliance in healthy mice or 2.3 ± 1 μL/cmH2O (n = 17). The technique detected changes in models of respiratory obstructive and restrictive diseases relative to control mice as well as differences in the two emphysema models studied. The changes in Caw were consistent with those seen in ΔCaw/ΔC, mWOB, or Ers_20.5, with some variations according to the model, as well as with results reported in the literature in humans and mice. Direct Caw measurements in subjects as small as mice could prove useful to further characterize other respiratory disease models associated with airway remodeling or to assess treatment effects.
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Affiliation(s)
| | | | - Samuel L Collins
- Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Jeffrey Martin Loube
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Yumiko Ishii
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Maureen R Horton
- Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - James G Martin
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Wayne Mitzner
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
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7
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Sattari S, Mariano CA, Vittalbabu S, Velazquez JV, Postma J, Horst C, Teh E, Nordgren TM, Eskandari M. Introducing a Custom-Designed Volume-Pressure Machine for Novel Measurements of Whole Lung Organ Viscoelasticity and Direct Comparisons Between Positive- and Negative-Pressure Ventilation. Front Bioeng Biotechnol 2020; 8:578762. [PMID: 33195138 PMCID: PMC7643401 DOI: 10.3389/fbioe.2020.578762] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022] Open
Abstract
Asthma, emphysema, COVID-19 and other lung-impacting diseases cause the remodeling of tissue structural properties and can lead to changes in conducting pulmonary volume, viscoelasticity, and air flow distribution. Whole organ experimental inflation tests are commonly used to understand the impact of these modifications on lung mechanics. Here we introduce a novel, automated, custom-designed device for measuring the volume and pressure response of lungs, surpassing the capabilities of traditional machines and built to range size-scales to accommodate both murine and porcine tests. The software-controlled system is capable of constructing standardized continuous volume-pressure curves, while accounting for air compressibility, yielding consistent and reproducible measures while eliminating the need for pulmonary degassing. This device uses volume-control to enable viscoelastic whole lung macromechanical insights from rate dependencies and pressure-time curves. Moreover, the conceptual design of this device facilitates studies relating the phenomenon of diaphragm breathing and artificial ventilation induced by pushing air inside the lungs. System capabilities are demonstrated and validated via a comparative study between ex vivo murine lungs and elastic balloons, using various testing protocols. Volume-pressure curve comparisons with previous pressure-controlled systems yield good agreement, confirming accuracy. This work expands the capabilities of current lung experiments, improving scientific investigations of healthy and diseased pulmonary biomechanics. Ultimately, the methodologies demonstrated in the manufacturing of this system enable future studies centered on investigating viscoelasticity as a potential biomarker and improvements to patient ventilators based on direct assessment and comparisons of positive- and negative-pressure mechanics.
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Affiliation(s)
- Samaneh Sattari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Crystal A Mariano
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Swathi Vittalbabu
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Jalene V Velazquez
- BREATHE Center at the School of Medicine, University of California, Riverside, Riverside, CA, United States.,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | | | - Caleb Horst
- CellScale Biomaterials Testing, Waterloo, ON, Canada
| | - Eric Teh
- CellScale Biomaterials Testing, Waterloo, ON, Canada
| | - Tara M Nordgren
- BREATHE Center at the School of Medicine, University of California, Riverside, Riverside, CA, United States.,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Mona Eskandari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States.,BREATHE Center at the School of Medicine, University of California, Riverside, Riverside, CA, United States.,Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
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8
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Kollisch-Singule M, Satalin J, Blair SJ, Andrews PL, Gatto LA, Nieman GF, Habashi NM. Mechanical Ventilation Lessons Learned From Alveolar Micromechanics. Front Physiol 2020; 11:233. [PMID: 32265735 PMCID: PMC7105828 DOI: 10.3389/fphys.2020.00233] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/28/2020] [Indexed: 01/05/2023] Open
Abstract
Morbidity and mortality associated with lung injury remains disappointingly unchanged over the last two decades, in part due to the current reliance on lung macro-parameters set on the ventilator instead of considering the micro-environment and the response of the alveoli and alveolar ducts to ventilator adjustments. The response of alveoli and alveolar ducts to mechanical ventilation modes cannot be predicted with current bedside methods of assessment including lung compliance, oxygenation, and pressure-volume curves. Alveolar tidal volumes (Vt) are less determined by the Vt set on the mechanical ventilator and more dependent on the number of recruited alveoli available to accommodate that Vt and their heterogeneous mechanical properties, such that high lung Vt can lead to a low alveolar Vt and low Vt can lead to high alveolar Vt. The degree of alveolar heterogeneity that exists cannot be predicted based on lung calculations that average the individual alveolar Vt and compliance. Finally, the importance of time in promoting alveolar stability, specifically the inspiratory and expiratory times set on the ventilator, are currently under-appreciated. In order to improve outcomes related to lung injury, the respiratory physiology of the individual patient, specifically at the level of the alveolus, must be targeted. With experimental data, this review highlights some of the known mechanical ventilation adjustments that are helpful or harmful at the level of the alveolus.
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Affiliation(s)
| | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Sarah J. Blair
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Penny L. Andrews
- Department of Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD, United States
| | - Louis A. Gatto
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
- Department of Biological Sciences, SUNY Cortland, Cortland, NY, United States
| | - Gary F. Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Nader M. Habashi
- Department of Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD, United States
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9
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Hermann-Sorensen H, Thometz NM, Woodie K, Dennison-Gibby S, Reichmuth C. In Vivo Measurements of Lung Volumes in Ringed Seals: Insights from Biomedical Imaging. J Exp Biol 2020:jeb.235507. [PMID: 34005800 DOI: 10.1242/jeb.235507] [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: 08/17/2020] [Accepted: 12/11/2020] [Indexed: 11/20/2022]
Abstract
Marine mammals rely on oxygen stored in blood, muscle, and lungs to support breath-hold diving and foraging at sea. Here, we used biomedical imaging to examine lung oxygen stores and other key respiratory parameters in living ringed seals (Pusa hispida). Three-dimensional models created from computed tomography (CT) images were used to quantify total lung capacity (TLC), respiratory dead space, minimum air volume, and total body volume to improve assessments of lung oxygen storage capacity, scaling relationships, and buoyant force estimates. Results suggest that lung oxygen stores determined in vivo are smaller than those derived from postmortem measurements. We also demonstrate that-while established allometric relationships hold well for most pinnipeds-these relationships consistently overestimate TLC for the smallest phocid seal. Finally, measures of total body volume reveal differences in body density and net vertical forces in the water column that influence costs associated with diving and foraging in free-ranging seals.
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Affiliation(s)
- Holly Hermann-Sorensen
- University of California Santa Cruz. Department of Ocean Sciences, 115 McAllister Way, Santa Cruz CA 95060, USA
| | - Nicole M Thometz
- University of San Francisco, Department of Biology. 2130 Fulton Street, San Francisco, CA 94117, USA
- University of California Santa Cruz. Institute of Marine Sciences, 115 McAllister Way, Santa Cruz CA 95060, USA
| | - Kathleen Woodie
- Alaska SeaLife Center, 301 Railway Ave, Seward, AK 99664, USA
| | | | - Colleen Reichmuth
- Alaska SeaLife Center, 301 Railway Ave, Seward, AK 99664, USA
- University of California Santa Cruz. Institute of Marine Sciences, 115 McAllister Way, Santa Cruz CA 95060, USA
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10
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Reyes-Caballero H, Park B, Loube J, Sanchez I, Vinayachandran V, Choi Y, Woo J, Edwards J, Brinkman MC, Sussan T, Mitzner W, Biswal S. Immune modulation by chronic exposure to waterpipe smoke and immediate-early gene regulation in murine lungs. Tob Control 2019; 29:s80-s89. [PMID: 31852817 DOI: 10.1136/tobaccocontrol-2019-054965] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 08/22/2019] [Accepted: 08/24/2019] [Indexed: 01/02/2023]
Abstract
OBJECTIVE We investigated the effects of chronic waterpipe (WP) smoke on pulmonary function and immune response in a murine model using a research-grade WP and the effects of acute exposure on the regulation of immediate-early genes (IEGs). METHODS WP smoke was generated using three WP smoke puffing regimens based on the Beirut regimen. WP smoke samples generated under these puffing regimens were quantified for nicotine concentration. Mice were chronically exposed for 6 months followed by assessment of pulmonary function and airway inflammation. Transcriptomic analysis using RNAseq was conducted after acute exposure to characterise the IEG response. These biomarkers were then compared with those generated after exposure to dry smoke (without water added to the WP bowl). RESULTS We determined that nicotine composition in WP smoke ranged from 0.4 to 2.5 mg per puffing session. The lung immune response was sensitive to the incremental severity of chronic exposure, with modest decreases in airway inflammatory cells and chemokine levels compared with air-exposed controls. Pulmonary function was unmodified by chronic WP exposure. Acute WP exposure was found to activate the immune response and identified known and novel IEG as potential biomarkers of WP exposure. CONCLUSION Chronic exposure to WP smoke leads to immune suppression without significant changes to pulmonary function. Transcriptomic analysis of the lung after acute exposure to WP smoke showed activation of the immune response and revealed IEGs that are common to WP and dry smoke, as well as pools of IEGs unique to each exposure, identifying potential biomarkers specific to WP exposure.
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Affiliation(s)
- Hermes Reyes-Caballero
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Bongsoo Park
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jeffrey Loube
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ian Sanchez
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Vinesh Vinayachandran
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Youngshim Choi
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Juhyung Woo
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Justin Edwards
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Thomas Sussan
- Toxicology Directorate, US Army Public Health Command, Aberdeen Proving Ground, Maryland, USA
| | - Wayne Mitzner
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Shyam Biswal
- Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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11
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Boehm O, Rohner M, Ehrentraut H, Guenther U, Meyer R, Knuefermann P, Baumgarten G, Duerr GD, Velten M. Low-tidal-volume prevent ventilation induced inflammation in a mouse model of sepsis. Life Sci 2019; 240:117081. [PMID: 31756342 DOI: 10.1016/j.lfs.2019.117081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/12/2019] [Accepted: 11/14/2019] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND GOAL OF THE STUDY Pulmonary inflammation, increased vascular permeability, and pulmonary edema, occur in response to primary pulmonary infections like pneumonia but are also evident in endotoxemia or sepsis. Mechanical ventilation augments pre-existing lung injury and inflammation resulting from exposure to microbial products. The objective of this study was to test the hypothesis that low-tidal-volume prevent ventilation induced lung injury in sepsis. MATERIALS AND METHODS 10-12-week-old male C57BL/6N-mice received an intraperitoneal (i.p.) injection with equipotent dosages of LPS, 1668-thioate, 1612-thioate, or PBS. 120 min after injection, mice were randomized to low- (LV, 7 ± 1 ml/kg) or high-tidal-volume (HV, 25 ± 1 ml/kg) ventilation. Hemodynamic and ventilatory parameters were recorded and inflammatory markers were analyzed form BAL that was generated after 90 minute ventilation. RESULTS AND DISCUSSION Arterial blood pressures declined during mechanical ventilation in all groups. pO2 decreased in LPS injected and CO2 increased in sham, LPS, and 1612-thioate administered mice at 45 min and in 1668-thioate injected mice after 90 minute LV ventilation compared to respective HV groups. BAL protein concentrations increased in HV ventilated and 1668- or 1612-thioat pre-treated mice. BAL TNF-α protein concentrations increased in both LPS- and 1668-thioate-injected and IL-1β protein concentrations only in LPS-injected and HV ventilated mice. Most notably, no increased protein concentrations were observed in any of the LV ventilated groups. CONCLUSION We conclude that low-tidal-volume ventilation may be a potential strategy for the prevention of ventilator induced lung injury in a murine model of systemic TLR agonist induced lung injury.
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Affiliation(s)
- Olaf Boehm
- Department of Anesthesiology and Intensive Care Medicine, Rheinische Friedrich-Wilhelms-University Medical Center, Bonn, Germany
| | - Marc Rohner
- Department of Anesthesiology and Intensive Care Medicine, Rheinische Friedrich-Wilhelms-University Medical Center, Bonn, Germany
| | - Heidi Ehrentraut
- Department of Anesthesiology and Intensive Care Medicine, Rheinische Friedrich-Wilhelms-University Medical Center, Bonn, Germany
| | - Ulf Guenther
- Department of Anesthesiology, Critical Care, Emergency Medicine and Pain Therapy, Klinikum Oldenburg, Medical Campus University of Oldenburg, Germany
| | - Rainer Meyer
- Institute of Physiology, Rheinische Friedrich-Wilhelms-University, Bonn, Germany
| | | | | | - Georg Daniel Duerr
- Department of Cardiac Surgery, Rheinische Friedrich-Wilhelms-University Medical Center, Bonn, Germany
| | - Markus Velten
- Department of Anesthesiology and Intensive Care Medicine, Rheinische Friedrich-Wilhelms-University Medical Center, Bonn, Germany.
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12
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Yang L, Feuchtinger A, Möller W, Ding Y, Kutschke D, Möller G, Schittny JC, Burgstaller G, Hofmann W, Stoeger T, Walch A, Schmid O. Three-Dimensional Quantitative Co-Mapping of Pulmonary Morphology and Nanoparticle Distribution with Cellular Resolution in Nondissected Murine Lungs. ACS NANO 2019; 13:1029-1041. [PMID: 30566327 DOI: 10.1021/acsnano.8b07524] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Deciphering biodistribution, biokinetics, and biological effects of nanoparticles (NPs) in entire organs with cellular resolution remains largely elusive due to the lack of effective imaging tools. Here, light sheet fluorescence microscopy in combination with optical tissue clearing was validated for concomitant three-dimensional mapping of lung morphology and NP biodistribution with cellular resolution in nondissected ex vivo murine lungs. Tissue autofluorescence allowed for label-free, quantitative morphometry of the entire bronchial tree, acinar structure, and blood vessels. Co-registration of fluorescent NPs with lung morphology revealed significant differences in pulmonary NP distribution depending on the means of application (intratracheal instillation and ventilator-assisted aerosol inhalation under anesthetized conditions). Inhalation exhibited a more homogeneous NP distribution in conducting airways and acini indicated by a central-to-peripheral (C/P) NP deposition ratio of unity (0.98 ± 0.13) as compared to a 2-fold enhanced central deposition (C/P = 1.98 ± 0.37) for instillation. After inhalation most NPs were observed in the proximal part of the acini as predicted by computational fluid dynamics simulations. At cellular resolution patchy NP deposition was visualized in bronchioles and acini, but more pronounced for instillation. Excellent linearity of the fluorescence intensity-dose response curve allowed for accurate NP dosimetry and revealed ca. 5% of the inhaled aerosol was deposited in the lungs. This single-modality imaging technique allows for quantitative co-registration of tissue architecture and NP biodistribution, which could accelerate elucidation of NP biokinetics and bioactivity within intact tissues, facilitating both nanotoxicology studies and the development of nanomedicines.
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Affiliation(s)
- Lin Yang
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
- Faculty of Medicine , Technical University of Munich , Munich , 80333 , Germany
| | - Annette Feuchtinger
- Research Unit Analytical Pathology , Helmholtz Zentrum München , Neuherberg , 85764 , Germany
| | - Winfried Möller
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
| | - Yaobo Ding
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
| | - David Kutschke
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
| | - Gabriele Möller
- Department Genome Analysis Center , Institute of Experimental Genetics, Helmholtz Zentrum München , Neuherberg , 85764 , Germany
| | | | - Gerald Burgstaller
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
| | - Werner Hofmann
- Department of Chemistry and Physics of Materials , University of Salzburg , Salzburg , A-5020 , Austria
| | - Tobias Stoeger
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
| | - Alex Walch
- Research Unit Analytical Pathology , Helmholtz Zentrum München , Neuherberg , 85764 , Germany
| | - Otmar Schmid
- Comprehensive Pneumology Center (CPC-M) , Member of the German Center for Lung Research (DZL) , Munich , 81377 , Germany
- Institute of Lung Biology and Disease , Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg , 85764 , Germany
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13
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Younas H, Vieira M, Gu C, Lee R, Shin MK, Berger S, Loube J, Nelson A, Bevans-Fonti S, Zhong Q, D'Alessio FR, McCormack MC, Hansel NN, Mitzner W, Polotsky VY. Caloric restriction prevents the development of airway hyperresponsiveness in mice on a high fat diet. Sci Rep 2019; 9:279. [PMID: 30670753 PMCID: PMC6342916 DOI: 10.1038/s41598-018-36651-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 11/22/2018] [Indexed: 12/20/2022] Open
Abstract
We have previously shown that high fat diet (HFD) for 2 weeks increases airway hyperresponsiveness (AHR) to methacholine challenge in C57BL/6J mice in association with an increase in IL-1β levels in lung tissue. We hypothesize that obesity increases AHR via the IL-1β mechanism, which can be prevented by caloric restriction and IL-1β blockade. In this study, we fed C57BL/6J mice for 8 weeks with several hypercaloric diets, including HFD, HFD supplemented with fructose, high trans-fat diet (HTFD) supplemented with fructose, either ad libitum or restricting their food intake to match body weight to the mice on a chow diet (CD). We also assessed the effect of the IL-1β receptor blocker anakinra. All mice showed the same total respiratory resistance at baseline. All obese mice showed higher AHR at 30 mg/ml of methacholine compared to CD and food restricted groups, regardless of the diet. Obese mice showed significant increases in lung IL-1 β mRNA expression, but not the protein, compared to CD and food restricted mice. Anakinra abolished an increase in AHR. We conclude that obesity leads to the airway hyperresponsiveness preventable by caloric restriction and IL-1β blockade.
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Affiliation(s)
- Haris Younas
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marcela Vieira
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chenjuan Gu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rachel Lee
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mi-Kyung Shin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Slava Berger
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeff Loube
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Andrew Nelson
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Shannon Bevans-Fonti
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Qiong Zhong
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Franco R D'Alessio
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Meredith C McCormack
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nadia N Hansel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wayne Mitzner
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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14
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Abstract
The experiment was conducted to examine the effect of a high fat diet (HFD) on airway hyperresponsiveness (AHR) in mice. Twenty-three adult male C57BL/6 J mice were fed with HFD or regular chow diet for two weeks. The total respiratory resistance was measured by forced oscillation technique at baseline and after methacholine aerosol challenge at 1, 3, 10 and 30 mg/mL. Bronchoalveolar lavage (BAL) was performed. Lipid levels and lipid peroxidation in lung tissue were measured along with gene expression of multiple cytokines. Lungs were digested, and IL-1β secretion by pulmonary macrophages was determined. HFD feeding resulted in 11% higher body weight compared to chow. HFD did not affect respiratory resistance at baseline, but significantly augmented airway responses to methacholine compared to chow diet (40.5 ± 17.7% increase at 30 mg/ml methacholine, p < 0.05). HFD induced a 3.2 ± 0.6 fold increase in IL-1β gene expression (p < 0.001) and a 38 fold increase in IL-1β secretion in the lungs. There was no change in BAL and no change in any other cytokines, lipid levels or lipid peroxidation. Hence, HFD induced AHR in mice prior to the development of significant obesity which was associated with up-regulation of pulmonary IL-1β.
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15
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Abstract
Breath-hold diving is practiced by recreational divers, seafood divers, military divers, and competitive athletes. It involves highly integrated physiology and extreme responses. This article reviews human breath-hold diving physiology beginning with an historical overview followed by a summary of foundational research and a survey of some contemporary issues. Immersion and cardiovascular adjustments promote a blood shift into the heart and chest vasculature. Autonomic responses include diving bradycardia, peripheral vasoconstriction, and splenic contraction, which help conserve oxygen. Competitive divers use a technique of lung hyperinflation that raises initial volume and airway pressure to facilitate longer apnea times and greater depths. Gas compression at depth leads to sequential alveolar collapse. Airway pressure decreases with depth and becomes negative relative to ambient due to limited chest compliance at low lung volumes, raising the risk of pulmonary injury called "squeeze," characterized by postdive coughing, wheezing, and hemoptysis. Hypoxia and hypercapnia influence the terminal breakpoint beyond which voluntary apnea cannot be sustained. Ascent blackout due to hypoxia is a danger during long breath-holds, and has become common amongst high-level competitors who can suppress their urge to breathe. Decompression sickness due to nitrogen accumulation causing bubble formation can occur after multiple repetitive dives, or after single deep dives during depth record attempts. Humans experience responses similar to those seen in diving mammals, but to a lesser degree. The deepest sled-assisted breath-hold dive was to 214 m. Factors that might determine ultimate human depth capabilities are discussed. © 2018 American Physiological Society. Compr Physiol 8:585-630, 2018.
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16
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Truflandier K, Beaumont E, Charbonney E, Maghni K, de Marchie M, Spahija J. Mechanical ventilation modulates pro-inflammatory cytokine expression in spinal cord tissue after injury in rats. Neurosci Lett 2018; 671:13-18. [PMID: 29355694 DOI: 10.1016/j.neulet.2018.01.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 01/15/2018] [Accepted: 01/15/2018] [Indexed: 11/24/2022]
Abstract
RATIONALE Spinal cord injury (SCI) may induce significant respiratory muscle weakness and paralysis, which in turn may cause a patient to require ventilator support. Central nervous system alterations can also exacerbate local inflammatory responses with immune cell infiltration leading to additional risk of inflammation at the injury site. Although mechanical ventilation is the traditional treatment for respiratory insufficiency, evidence has shown that it may directly affect distant organs through systemic inflammation. OBJECTIVES This study aimed to better understand the impact of invasive mechanical ventilation on local spinal cord inflammatory responses following cervical or thoracic SCI. METHODS Five groups of female Sprague-Dawley rats were anesthetised for 24 h. Three groups received mechanical ventilation: seven rats without SCI, seven rats with cervical injury (C4-C5), and seven rats with thoracic injury (T10); whereas, two groups were non-ventilated: six rats without SCI; and six rats with thoracic injury (T10). Changes in inflammatory responses were determined in the spinal cord tissues collected at the local site of injury. Cytokines were measured using ELISA. MAIN RESULTS SCI induced local pro-inflammatory cytokine IL-6 expression for all groups. Mechanical ventilation also had effects on pro-inflammatory cytokines and independently increased TNF-α and decreased IL-1β levels in the spinal cords of anesthetized rats. CONCLUSION These data provide the first evidence that mechanical ventilation contributes to local inflammation after SCI and in the absence of direct tissue injury.
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Affiliation(s)
- Karine Truflandier
- Research Center, CIUSSS du Nord-de-l'Ile-de-Montréal, Sacré-Coeur Hospital, Department of Medicine, Université de Montréal, 5400 boul. Gouin Ouest, Montréal, Quebec, H4J 1C5, Canada
| | - Eric Beaumont
- Research Center, CIUSSS du Nord-de-l'Ile-de-Montréal, Sacré-Coeur Hospital, Department of Medicine, Université de Montréal, 5400 boul. Gouin Ouest, Montréal, Quebec, H4J 1C5, Canada; Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Emmanuel Charbonney
- Research Center, CIUSSS du Nord-de-l'Ile-de-Montréal, Sacré-Coeur Hospital, Department of Medicine, Université de Montréal, 5400 boul. Gouin Ouest, Montréal, Quebec, H4J 1C5, Canada
| | - Karim Maghni
- Research Center, CIUSSS du Nord-de-l'Ile-de-Montréal, Sacré-Coeur Hospital, Department of Medicine, Université de Montréal, 5400 boul. Gouin Ouest, Montréal, Quebec, H4J 1C5, Canada
| | - Michel de Marchie
- Department of Adult Critical Care, Jewish General Hospital, McGill University, Montreal, Quebec, H3T 1E2, Canada
| | - Jadranka Spahija
- Research Center, CIUSSS du Nord-de-l'Ile-de-Montréal, Sacré-Coeur Hospital, Department of Medicine, Université de Montréal, 5400 boul. Gouin Ouest, Montréal, Quebec, H4J 1C5, Canada; School of Physical and Occupational Therapy, McGill University, 3654 Promenade Sir William Osler, Montreal, Quebec, H3G 1Y5, Canada; Center for Interdisciplinary Research in Rehabilitation in Montreal, CISSS de Laval, Jewish Rehabilitation Hospital, 3205, Place Alton-Goldbloom, Laval, Quebec, H7V 1J1, Canada.
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17
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Saad M, Ruwanpura SM. Tissue Processing for Stereological Analyses of Lung Structure in Chronic Obstructive Pulmonary Disease. Methods Mol Biol 2018; 1725:155-162. [PMID: 29322416 DOI: 10.1007/978-1-4939-7568-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Quantitative data on lung structure, such as volume, surface area and length, are used for assessment of the functional performance of the lung during normal development and inflammatory-related diseases such as chronic obstructive pulmonary disorder (COPD), and carcinogenesis, in animal models. Stereology is considered as the gold standard to obtain quantitative data on lung structure, with a key advantage being to quantify irregular three-dimensional structures on the basis of measurement made on two-dimensional sections. Therefore, preservation of original tissue dimensions without shrinkage is vital for stereology.Three steps, fixation, sampling and embedding, are essential requirements to minimise tissue shrinkage to obtain theoretically unbiased estimates of stereological parameters of lung structures. Perfusion fixation by intratracheal instillation with 1.5% glutaraldehyde/1.5% formaldehyde at a pressure of 25 cm fluid column is considered as one of the best methods. A systematic uniform random sampling scheme is then applied to the fixed lung to ensure each and every part of the lung is analysed, irrespective of homogeneity or heterogeneity of the structural distribution. The sampled tissue sections are then embedded in glycol methacrylate to minimise further tissue shrinkage. Here we describe the accurate fixation, sampling and embedding for stereological methods to quantify lung structures in mice.
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Affiliation(s)
- Mohamed Saad
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular Translational Science, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - Saleela M Ruwanpura
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.
- Department of Molecular Translational Science, School of Clinical Sciences, Monash University, Clayton, VIC, Australia.
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18
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Jenkins RG, Moore BB, Chambers RC, Eickelberg O, Königshoff M, Kolb M, Laurent GJ, Nanthakumar CB, Olman MA, Pardo A, Selman M, Sheppard D, Sime PJ, Tager AM, Tatler AL, Thannickal VJ, White ES. An Official American Thoracic Society Workshop Report: Use of Animal Models for the Preclinical Assessment of Potential Therapies for Pulmonary Fibrosis. Am J Respir Cell Mol Biol 2017; 56:667-679. [PMID: 28459387 DOI: 10.1165/rcmb.2017-0096st] [Citation(s) in RCA: 240] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Numerous compounds have shown efficacy in limiting development of pulmonary fibrosis using animal models, yet few of these compounds have replicated these beneficial effects in clinical trials. Given the challenges associated with performing clinical trials in patients with idiopathic pulmonary fibrosis (IPF), it is imperative that preclinical data packages be robust in their analyses and interpretations to have the best chance of selecting promising drug candidates to advance to clinical trials. The American Thoracic Society has convened a group of experts in lung fibrosis to discuss and formalize recommendations for preclinical assessment of antifibrotic compounds. The panel considered three major themes (choice of animal, practical considerations of fibrosis modeling, and fibrotic endpoints for evaluation). Recognizing the need for practical considerations, we have taken a pragmatic approach. The consensus view is that use of the murine intratracheal bleomycin model in animals of both genders, using hydroxyproline measurements for collagen accumulation along with histologic assessments, is the best-characterized animal model available for preclinical testing. Testing of antifibrotic compounds in this model is recommended to occur after the acute inflammatory phase has subsided (generally after Day 7). Robust analyses may also include confirmatory studies in human IPF specimens and validation of results in a second system using in vivo or in vitro approaches. The panel also strongly encourages the publication of negative results to inform the lung fibrosis community. These recommendations are for preclinical therapeutic evaluation only and are not intended to dissuade development of emerging technologies to better understand IPF pathogenesis.
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Robichaud A, Fereydoonzad L, Limjunyawong N, Rabold R, Allard B, Benedetti A, Martin JG, Mitzner W. Automated full-range pressure-volume curves in mice and rats. J Appl Physiol (1985) 2017; 123:746-756. [PMID: 28751375 DOI: 10.1152/japplphysiol.00856.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 11/22/2022] Open
Abstract
Pressure-volume (PV) curves constructed over the entire lung volume range can reliably detect functional changes in mouse models of lung diseases. In the present study, we constructed full-range PV curves in healthy and elastase-treated mice using either a classic manually operated technique or an automated approach using a computer-controlled piston ventilator [flexiVent FX; Scientific Respiratory Equipment (SCIREQ), Montreal, Quebec, Canada]. On the day of the experiment, subjects were anesthetized, tracheotomized, and mechanically ventilated. Following an initial respiratory mechanics scan and degassing of the lungs with 100% O2, full-range PV curves were constructed using either the classic or the automated technique. In control mice, superimposable curves were obtained, and statistical equivalence was attained between the two methodologies. In the elastase-treated ones, where significant changes in respiratory mechanics and lung volumes were expected, very small differences were observed between the two techniques, and the criteria for statistical equivalence were met in two out of four parameters assessed. The automated technique was adapted to rats and used to estimate the functional residual capacity (FRC) by volume subtraction. This novel approach generated FRC estimates consistent with the literature, with added accuracy relative to the existing method in diseased subjects. In conclusion, the automated technique generated full-range PV curves that were equivalent or very close to those obtained with the classic method under physiological or severe pathological conditions. The automation facilitated some technical aspects of the procedure, eased its use across species, and helped derive a more accurate estimate of FRC in preclinical models of respiratory disease.NEW & NOTEWORTHY Partial and full-range pressure-volume (PV) curves are frequently used to characterize lung disease models. Whereas automated techniques exist to construct partial PV curves, a manually operated approach is classically employed to build the full-range ones. In this study, the full-range PV curve technique was automated using a computer-controlled piston ventilator. The automation simplified the technique, facilitated its extension to other species, and inspired a novel way of estimating the functional residual capacity in laboratory rodents.
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Affiliation(s)
| | | | - Nathachit Limjunyawong
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland; and
| | - Richard Rabold
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland; and
| | - Benoit Allard
- Meakins-Christie Laboratories, Department of Medicine, McGill University and the Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Andrea Benedetti
- Meakins-Christie Laboratories, Department of Medicine, McGill University and the Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - James G Martin
- Meakins-Christie Laboratories, Department of Medicine, McGill University and the Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Wayne Mitzner
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland; and
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20
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Yablonskiy DA, Sukstanskii AL, Quirk JD. Diffusion lung imaging with hyperpolarized gas MRI. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3448. [PMID: 26676342 PMCID: PMC4911335 DOI: 10.1002/nbm.3448] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/20/2015] [Accepted: 10/22/2015] [Indexed: 05/28/2023]
Abstract
Lung imaging using conventional 1 H MRI presents great challenges because of the low density of lung tissue, lung motion and very fast lung tissue transverse relaxation (typical T2 * is about 1-2 ms). MRI with hyperpolarized gases (3 He and 129 Xe) provides a valuable alternative because of the very strong signal originating from inhaled gas residing in the lung airspaces and relatively slow gas T2 * relaxation (typical T2 * is about 20-30 ms). However, in vivo human experiments should be performed very rapidly - usually during a single breath-hold. In this review, we describe the recent developments in diffusion lung MRI with hyperpolarized gases. We show that a combination of the results of modeling of gas diffusion in lung airspaces and diffusion measurements with variable diffusion-sensitizing gradients allows the extraction of quantitative information on the lung microstructure at the alveolar level. From an MRI scan of less than 15 s, this approach, called in vivo lung morphometry, allows the provision of quantitative values and spatial distributions of the same physiological parameters as measured by means of 'standard' invasive stereology (mean linear intercept, surface-to-volume ratio, density of alveoli, etc.). In addition, the approach makes it possible to evaluate some advanced Weibel parameters characterizing lung microstructure: average radii of alveolar sacs and ducts, as well as the depth of their alveolar sleeves. Such measurements, providing in vivo information on the integrity of pulmonary acinar airways and their changes in different diseases, are of great importance and interest to a broad range of physiologists and clinicians. We also discuss a new type of experiment based on the in vivo lung morphometry technique combined with quantitative computed tomography measurements, as well as with gradient echo MRI measurements of hyperpolarized gas transverse relaxation in the lung airspaces. Such experiments provide additional information on the blood vessel volume fraction, specific gas volume and length of the acinar airways, and allow the evaluation of lung parenchymal and non-parenchymal tissue. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
| | | | - James D Quirk
- Department of Radiology, Washington University, St. Louis, MO, USA
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21
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Abstract
The mouse lung has become increasingly important as a surrogate of the human lung for inhalation risk assessment. The main structural difference between the two lungs is that the airway branching of the human lung is relatively symmetric, while that of the mouse lung is distinctly asymmetric or monopodial. The objectives of this study were to develop a stochastic, asymmetric particle deposition model for the Balb/c mouse and to compare predicted deposition patterns with those in the human lung. The asymmetric bronchial airway geometry of the Balb/c mouse was based on a statistical analysis of several lung casts, while, in the absence of pertinent data, the asymmetric acinar airway geometry was represented by an allometrically scaled-down version of the rat acinar region, assuming structural similarity. Deposition of inhaled particles in nasal, bronchial and acinar airways for mouse-specific breathing conditions was computed with the Monte Carlo deposition model IDEAL-mouse. While total deposition for submicron particles decreases with increasing diameter in a fashion similar to that in the human lung, the effect of inhalability and nasal pre-filtration significantly reduces total deposition in the mouse lung for particles with diameters greater than about 3 μm. The most notable difference between submicron particle deposition in the mouse and human airways is the shift of the deposition distribution from distal airway generations in the human lung to upper airway generations in the mouse lung. However, if plotted as a function of airway diameter, both deposition distributions are quite similar, indicating that airway diameter may be a more appropriate morphometric parameter for extrapolation purposes than airway generation.
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Affiliation(s)
- Renate Winkler-Heil
- a Division of Physics and Biophysics , Department of Chemistry and Physics of Materials, University of Salzburg , Salzburg , Austria
| | - Werner Hofmann
- a Division of Physics and Biophysics , Department of Chemistry and Physics of Materials, University of Salzburg , Salzburg , Austria
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22
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Kizhakke Puliyakote AS, Vasilescu DM, Newell JD, Wang G, Weibel ER, Hoffman EA. Morphometric differences between central vs. surface acini in A/J mice using high-resolution micro-computed tomography. J Appl Physiol (1985) 2016; 121:115-22. [PMID: 27174924 DOI: 10.1152/japplphysiol.00317.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/06/2016] [Indexed: 11/22/2022] Open
Abstract
Through interior tomography, high-resolution microcomputed tomography (μCT) systems provide the ability to nondestructively assess the pulmonary acinus at micron and submicron resolutions. With the application of systematic uniform random sampling (SURS) principles applied to in situ fixed, intact, ex vivo lungs, we have sought to characterize morphometric differences in central vs. surface acini to better understand how well surface acini reflect global acinar geometry. Lungs from six mice (A/J strain, 15-20 wk of age) were perfusion fixed in situ and imaged using a multiresolution μCT system (Micro XCT 400, Zeiss). With the use of lower-resolution whole lung images, SURS methods were used for identification of central and surface foci for high-resolution imaging. Acinar morphometric metrics included diameters, lengths, and branching angles for each alveolar duct and total path lengths from entrance of the acinus to the terminal alveolar sacs. In addition, acinar volume, alveolar surface area, and surface area/volume ratios were assessed. A generation-based analysis demonstrated that central acini have significantly smaller branch diameters at each generation with no significant increase in branch lengths. In addition to larger-diameter alveolar ducts, surface acini had significantly increased numbers of branches and terminal alveolar sacs. The total path lengths from the acinar entrance to the terminal nodes were found to be higher in the case of surface acini. Volumes and surface areas of surface acini are greater than central acini, but there were no differences in surface/volume ratios. In conclusion, there are significant structural differences between surface and central acini in the A/J mouse.
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Affiliation(s)
- Abhilash S Kizhakke Puliyakote
- Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa
| | | | - John D Newell
- Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa
| | - Ge Wang
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; Department of Biomedical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | | | - Eric A Hoffman
- Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa; Department of Medicine, University of Iowa, Iowa City, Iowa;
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23
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Oliveira CLN, Araújo AD, Bates JHT, Andrade JS, Suki B. Entropy Production and the Pressure-Volume Curve of the Lung. Front Physiol 2016; 7:73. [PMID: 26973540 PMCID: PMC4771753 DOI: 10.3389/fphys.2016.00073] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/15/2016] [Indexed: 02/02/2023] Open
Abstract
We investigate analytically the production of entropy during a breathing cycle in healthy and diseased lungs. First, we calculate entropy production in healthy lungs by applying the laws of thermodynamics to the well-known transpulmonary pressure–volume (P–V) curves of the lung under the assumption that lung tissue behaves as an entropic spring similar to rubber. The bulk modulus, B, of the lung is also derived from these calculations. Second, we extend this approach to elastic recoil disorders of the lung such as occur in pulmonary fibrosis and emphysema. These diseases are characterized by particular alterations in the P–V relationship. For example, in fibrotic lungs B increases monotonically with disease progression, while in emphysema the opposite occurs. These diseases can thus be mimicked simply by making appropriate adjustments to the parameters of the P–V curve. Using Clausius's formalism, we show that entropy production, ΔS, is related to the hysteresis area, ΔA, enclosed by the P–V curve during a breathing cycle, namely, ΔS=ΔA∕T, where T is the body temperature. Although ΔA is highly dependent on the disease, such formula applies to healthy as well as diseased lungs, regardless of the disease stage. Finally, we use an ansatz to predict analytically the entropy produced by the fibrotic and emphysematous lungs.
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Affiliation(s)
| | - Ascânio D Araújo
- Departamento de Física, Universidade Federal do Ceará Fortaleza, Brazil
| | - Jason H T Bates
- Department of Medicine, University of Vermont Burlington, VT, USA
| | - José S Andrade
- Departamento de Física, Universidade Federal do Ceará Fortaleza, Brazil
| | - Béla Suki
- Department of Biomedical Engineering, Boston University Boston, MA, USA
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24
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Yablonskiy DA, Sukstanskii AL, Quirk JD, Woods JC, Conradi MS. Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results. Magn Reson Med 2016; 71:486-505. [PMID: 23554008 DOI: 10.1002/mrm.24729] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The introduction of hyperpolarized gases ((3)He and (129)Xe) has opened the door to applications for which gaseous agents are uniquely suited-lung MRI. One of the pulmonary applications, diffusion MRI, relies on measuring Brownian motion of inhaled hyperpolarized gas atoms diffusing in lung airspaces. In this article we provide an overview of the theoretical ideas behind hyperpolarized gas diffusion MRI and the results obtained over the decade-long research. We describe a simple technique based on measuring gas apparent diffusion coefficient (ADC) and an advanced technique, in vivo lung morphometry, that quantifies lung microstructure both in terms of Weibel parameters (acinar airways radii and alveolar depth) and standard metrics (mean linear intercept, surface-to-volume ratio, and alveolar density) that are widely used by lung researchers but were previously available only from invasive lung biopsy. This technique has the ability to provide unique three-dimensional tomographic information on lung microstructure from a less than 15 s MRI scan with results that are in good agreement with direct histological measurements. These safe and sensitive diffusion measurements improve our understanding of lung structure and functioning in health and disease, providing a platform for monitoring the efficacy of therapeutic interventions in clinical trials.
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25
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Woods SJ, Waite AAC, O'Dea KP, Halford P, Takata M, Wilson MR. Kinetic profiling of in vivo lung cellular inflammatory responses to mechanical ventilation. Am J Physiol Lung Cell Mol Physiol 2015; 308:L912-21. [PMID: 25770178 PMCID: PMC4421782 DOI: 10.1152/ajplung.00048.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/07/2015] [Indexed: 02/07/2023] Open
Abstract
Mechanical ventilation, through overdistension of the lung, induces substantial inflammation that is thought to increase mortality among critically ill patients. The mechanotransduction processes involved in converting lung distension into inflammation during this ventilator-induced lung injury (VILI) remain unclear, although many cell types have been shown to be involved in its pathogenesis. This study aimed to identify the profile of in vivo lung cellular activation that occurs during the initiation of VILI. This was achieved using a flow cytometry-based method to quantify the phosphorylation of several markers (p38, ERK1/2, MAPK-activated protein kinase 2, and NF-κB) of inflammatory pathway activation within individual cell types. Anesthetized C57BL/6 mice were ventilated with low (7 ml/kg), intermediate (30 ml/kg), or high (40 ml/kg) tidal volumes for 1, 5, or 15 min followed by immediate fixing and processing of the lungs. Surprisingly, the pulmonary endothelium was the cell type most responsive to in vivo high-tidal-volume ventilation, demonstrating activation within just 1 min, followed by the alveolar epithelium. Alveolar macrophages were the slowest to respond, although they still demonstrated activation within 5 min. This order of activation was specific to VILI, since intratracheal lipopolysaccharide induced a very different pattern. These results suggest that alveolar macrophages may become activated via a secondary mechanism that occurs subsequent to activation of the parenchyma and that the lung cellular activation mechanism may be different between VILI and lipopolysaccharide. Our data also demonstrate that even very short periods of high stretch can promote inflammatory activation, and, importantly, this injury may be immediately manifested within the pulmonary vasculature.
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Affiliation(s)
- Samantha J. Woods
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom
| | - Alicia A. C. Waite
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom
| | - Kieran P. O'Dea
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom
| | - Paul Halford
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom
| | - Masao Takata
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom
| | - Michael R. Wilson
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom
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26
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Limjunyawong N, Fallica J, Horton MR, Mitzner W. Measurement of the pressure-volume curve in mouse lungs. J Vis Exp 2015:52376. [PMID: 25651276 DOI: 10.3791/52376] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In recent decades the mouse has become the primary animal model of a variety of lung diseases. In models of emphysema or fibrosis, the essential phenotypic changes are best assessed by measurement of the changes in lung elasticity. To best understand specific mechanisms underlying such pathologies in mice, it is essential to make functional measurements that can reflect the developing pathology. Although there are many ways to measure elasticity, the classical method is that of the total lung pressure-volume (PV) curve done over the whole range of lung volumes. This measurement has been made on adult lungs from nearly all mammalian species dating back almost 100 years, and such PV curves also played a major role in the discovery and understanding of the function of pulmonary surfactant in fetal lung development. Unfortunately, such total PV curves have not been widely reported in the mouse, despite the fact that they can provide useful information on the macroscopic effects of structural changes in the lung. Although partial PV curves measuring just the changes in lung volume are sometimes reported, without a measure of absolute volume, the nonlinear nature of the total PV curve makes these partial ones very difficult to interpret. In the present study, we describe a standardized way to measure the total PV curve. We have then tested the ability of these curves to detect changes in mouse lung structure in two common lung pathologies, emphysema and fibrosis. Results showed significant changes in several variables consistent with expected structural changes with these pathologies. This measurement of the lung PV curve in mice thus provides a straightforward means to monitor the progression of the pathophysiologic changes over time and the potential effect of therapeutic procedures.
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Affiliation(s)
- Nathachit Limjunyawong
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University
| | - Jonathan Fallica
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University
| | - Maureen R Horton
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University
| | - Wayne Mitzner
- Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University;
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27
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28
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Limjunyawong N, Mitzner W, Horton MR. A mouse model of chronic idiopathic pulmonary fibrosis. Physiol Rep 2014; 2:e00249. [PMID: 24744912 PMCID: PMC3966254 DOI: 10.1002/phy2.249] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 01/31/2014] [Accepted: 01/31/2014] [Indexed: 12/03/2022] Open
Abstract
Chronic idiopathic pulmonary fibrosis (IPF) is a progressive, fatal, and untreatable disease with unclear etiology. There are few models of this chronic pathology, and although delivery of bleomycin to induce acute lung injury is the most common animal model of pulmonary fibrosis, there is considerable uncertainty about whether this acute injury resolves in those animals that survive. In this report, we have systematically followed groups of mice for up to 6 months following a single insult of bleomycin. We assessed changes in lung function and pathology over this time course, with measurements of the diffusion capacity for carbon monoxide, lung mechanics, quantitative stereology, and collagen. Our results show that, while there is some repair over this extended time course, the injury in the lung never fully resolves. This persistent degree of fibrosis may have similarities to many features of human IPF. Thus, these chronic fibrotic changes in mouse lungs could be a useful model to evaluate potential therapeutic interventions to accelerate repair and possible treat this debilitating disease. Figure shows the durability of the bleomycin induced fibrosis over 6 month.
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Affiliation(s)
- Nathachit Limjunyawong
- Department of Environmental Health Sciences, Program in Respiratory Biology and Lung Diseases, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland21205, USA
| | - Wayne Mitzner
- Department of Environmental Health Sciences, Program in Respiratory Biology and Lung Diseases, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland21205, USA
| | - Maureen R. Horton
- Department of Environmental Health Sciences, Program in Respiratory Biology and Lung Diseases, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland21205, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland21205, USA
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29
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Wang W, Nguyen NM, Guo J, Woods JC. Longitudinal, noninvasive monitoring of compensatory lung growth in mice after pneumonectomy via (3)He and (1)H magnetic resonance imaging. Am J Respir Cell Mol Biol 2013; 49:697-703. [PMID: 23763461 DOI: 10.1165/rcmb.2012-0332ma] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In rodents and some other mammals, partial pneumonectomy (PNX) of adult lungs results in rapid compensatory lung growth. In the past, quantification of compensatory lung growth and realveolarization could only be accomplished after killing the animal, removal of lungs, and histologic analysis of lungs at single time points. Hyperpolarized (3)He diffusion magnetic resonance imaging (MRI) allows in vivo morphometry of human lungs; our group has adapted this technique for application to mouse lungs. Through imaging, we can obtain maps of lung microstructural parameters that allow quantification of morphometric and physiologic measurements. In this study, we employed our (3)He MRI technique to image in vivo morphometry at baseline and to serially assess compensatory growth after left PNX of mice. (1)H and hyperpolarized (3)He diffusion MRI were performed at baseline (pre-PNX), 3-days, and 30-days after PNX. Compared with the individual mouse's own baseline, MRI was able to detect and serially quantify changes in lung volume, alveolar surface area, alveolar number, and regional changes in alveolar size that occurred during the course of post-PNX lung growth. These results are consistent with morphometry measurements reported in the literature for mouse post-PNX compensatory lung growth. In addition, we were also able to serially assess and quantify changes in the physiologic parameter of lung compliance during the course of compensatory lung growth; this was consistent with flexiVent data. With these techniques, we now have a noninvasive, in vivo method to serially assess the effectiveness of therapeutic interventions on post-PNX lung growth in the same mouse.
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30
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Smith BJ, Bates JHT. Assessing the Progression of Ventilator-Induced Lung Injury in Mice. IEEE Trans Biomed Eng 2013; 60:3449-57. [PMID: 23751952 DOI: 10.1109/tbme.2013.2267151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Patients with acute respiratory distress syndrome receiving mechanical ventilation typically experience repetitive closure (derecruitment) and subsequent reopening (recruitment) of airways and alveoli. This can lead, over time, to further ventilator-induced lung injury (VILI). Recruitment and derecruitment (R/D) thus reflect both the current level of lung injury and the risk for sustaining further injury. Accordingly, we investigated how the dynamics of R/D are altered as VILI develops following application of high tidal volume ventilation in initially healthy mice. R/D occurring on subsecond timescales was assessed from the shape of the pressure-volume ( PV) loop measured during a single large breath. R/D occurring on a timescale of minutes was evaluated via a derecruitability test in which we tracked the progressive increases in lung elastance occurring during periods of mechanical ventilation immediately following a recruitment maneuver. The degrees of R/D occurring on these different times scales were strongly correlated. To interpret these findings in quantitative terms, we developed a computational model of the lung in which changes in lung volume occurred both via R/D and distention of already open lung units. Fitting this model to measured PV loops indicates that VILI causes R/D both to increase and to occur at progressively higher pressures, and that the lung tissue that remains open during the breath becomes progressively more overdistended. We conclude that the dynamic PV loop in conjunction with our computational model can be used to assess the current injury state of the lung as well as its likelihood of sustaining further VILI.
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31
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Sera T, Yokota H, Tanaka G, Uesugi K, Yagi N, Schroter RC. Murine pulmonary acinar mechanics during quasi-static inflation using synchrotron refraction-enhanced computed tomography. J Appl Physiol (1985) 2013; 115:219-28. [PMID: 23661619 DOI: 10.1152/japplphysiol.01105.2012] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We visualized pulmonary acini in the core regions of the mouse lung in situ using synchrotron refraction-enhanced computed tomography (CT) and evaluated their kinematics during quasi-static inflation. This CT system (with a cube voxel of 2.8 μm) allows excellent visualization of not just the conducting airways, but also the alveolar ducts and sacs, and tracking of the acinar shape and its deformation during inflation. The kinematics of individual alveoli and alveolar clusters with a group of terminal alveoli is influenced not only by the connecting alveolar duct and alveoli, but also by the neighboring structures. Acinar volume was not a linear function of lung volume. The alveolar duct diameter changed dramatically during inflation at low pressures and remained relatively constant above an airway pressure of ∼8 cmH2O during inflation. The ratio of acinar surface area to acinar volume indicates that acinar distension during low-pressure inflation differed from that during inflation over a higher pressure range; in particular, acinar deformation was accordion-like during low-pressure inflation. These results indicated that the alveoli and duct expand differently as total acinar volume increases and that the alveolar duct may expand predominantly during low-pressure inflation. Our findings suggest that acinar deformation in the core regions of the lung is complex and heterogeneous.
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Affiliation(s)
- Toshihiro Sera
- Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan.
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The extent of ventilator-induced lung injury in mice partly depends on duration of mechanical ventilation. Crit Care Res Pract 2013; 2013:435236. [PMID: 23691294 PMCID: PMC3652114 DOI: 10.1155/2013/435236] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/15/2013] [Accepted: 03/17/2013] [Indexed: 02/01/2023] Open
Abstract
Background. Mechanical ventilation (MV) has the potential to initiate ventilator-induced lung injury (VILI). The pathogenesis of VILI has been primarily studied in animal models using more or less injurious ventilator settings. However, we speculate that duration of MV also influences severity and character of VILI. Methods. Sixty-four healthy C57Bl/6 mice were mechanically ventilated for 5 or 12 hours, using lower tidal volumes with positive end-expiratory pressure (PEEP) or higher tidal volumes without PEEP. Fifteen nonventilated mice served as controls. Results. All animals remained hemodynamically stable and survived MV protocols. In both MV groups, PaO2 to FiO2 ratios were lower and alveolar cell counts were higher after 12 hours of MV compared to 5 hours. Alveolar-capillary permeability was increased after 12 hours compared to 5 hours, although differences did not reach statistical significance. Lung levels of inflammatory mediators did not further increase over time. Only in mice ventilated with increased strain, lung compliance declined and wet to dry ratio increased after 12 hours of MV compared to 5 hours. Conclusions. Deleterious effects of MV are partly dependent on its duration. Even lower tidal volumes with PEEP may initiate aspects of VILI after 12 hours of MV.
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Airway distension during lung inflation in healthy and allergic-sensitised mice in vivo. Respir Physiol Neurobiol 2012; 185:639-46. [PMID: 23253555 DOI: 10.1016/j.resp.2012.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/14/2012] [Accepted: 12/06/2012] [Indexed: 11/22/2022]
Abstract
We evaluated the airway distention during lung inflation of varying size in healthy and allergic-sensitised mice in vivo. Computed tomography (CT) images of healthy and ovalbumin-treated mice were acquired using a synchrotron in vivo CT system when lung pressures was 0 and 20 cmH(2)O, and the morphometric distension (diameter, length, and volume) and the compliance of airway segments (to as small as ~150 μm internal diameter) were calculated. With respect to airway size, in healthy mice, the changes in airway diameter and compliance were larger in the small-airway group. In contrast, in allergic-sensitised mice, there were no significant differences in the changes in airway distension or compliance. Airway wall thickness in allergic-sensitised mice increased significantly in all airway groups, but the change was much larger in the small than in the large-airway group. Compared with healthy airways, the changes in diameter and airway compliance of the allergic-sensitised mice were significantly smaller in the small-airway group.
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Affiliation(s)
- Gerald C Smaldone
- Pulmonary, Critical Care and Sleep Medicine, Stony Brook University Medical Center, Stony Brook, New York, USA
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Wilson MR, Patel BV, Takata M. Ventilation with "clinically relevant" high tidal volumes does not promote stretch-induced injury in the lungs of healthy mice. Crit Care Med 2012; 40:2850-7. [PMID: 22890257 PMCID: PMC3698535 DOI: 10.1097/ccm.0b013e31825b91ef] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Ventilator-induced lung injury is a crucial determinant of the outcome of mechanically ventilated patients. Increasing numbers of mouse studies have identified numerous pathways and mediators that are modulated by ventilation, but it is conceptually difficult to reconcile these into a single paradigm. There is substantial variability in tidal volumes used in these studies and no certainty about the pathophysiology that such varied models actually represent. This study was designed to investigate whether ventilation strategies ranging from "very high" to more "clinically relevant" tidal volumes induce similar pathophysiologies in healthy mice or represent distinct entities. DESIGN In vivo study. SETTING University research laboratory. SUBJECTS C57/Bl6 mice. INTERVENTIONS Anesthetized mice were ventilated with various tidal volumes up to 40 mL/kg. MEASUREMENTS AND MAIN RESULTS Respiratory system compliance and arterial blood gases were used to evaluate physiological variables of injury. Lung wet:dry weight ratio, lavage fluid protein, and cytokines were used to assess pulmonary edema and inflammation. All ventilation strategies induced changes in respiratory system compliance, although the pattern of change was unique for each strategy. Ventilation with 10 mL/kg and 40 mL/kg also induced decreases in arterial PO2 and blood pressure. Any physiological changes induced during the 10, 20, and 30 mL/kg strategies were largely reversed by recruitment maneuvers at the end of the protocol. Markers of pulmonary edema and inflammation indicated that only 40 mL/kg induced substantial increases in both, consistent with development of lung injury. CONCLUSIONS Tidal volumes up to 20 mL/kg are unlikely to induce substantial lung overstretch in models using healthy, young mice. Signs of injury/inflammation using such models are likely to result from other factors, particularly alveolar derecruitment and atelectasis. The results of such studies may need to be reevaluated before clinical relevance can be accurately determined.
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Affiliation(s)
- Michael R Wilson
- Section of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom.
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Fahlman A, Loring SH, Ferrigno M, Moore C, Early G, Niemeyer M, Lentell B, Wenzel F, Joy R, Moore MJ. Static inflation and deflation pressure-volume curves from excised lungs of marine mammals. ACTA ACUST UNITED AC 2012; 214:3822-8. [PMID: 22031747 DOI: 10.1242/jeb.056366] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Excised lungs from eight marine mammal species [harp seal (Pagophilus groenlandicus), harbor seal (Phoca vitulina), gray seal (Halichoerus grypush), Atlantic white-sided dolphin (Lagenorhynchus acutus), common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus), long-finned pilot whale (Globicephala melas) and harbor porpoise (Phocoena phocoena)] were used to determine the minimum air volume of the relaxed lung (MAV, N=15), the elastic properties (pressure-volume curves, N=24) of the respiratory system and the total lung capacity (TLC). Our data indicate that mass-specific TLC (sTLC, l kg(-1)) does not differ between species or groups (odontocete vs phocid) and agree with that estimated (TLC(est)) from body mass (M(b)) by applying the equation: TLC(est)=0.135 M(b)(0.92). Measured MAV was on average 7% of TLC, with a range from 0 to 16%. The pressure-volume curves were similar among species on inflation but diverged during deflation in phocids in comparison with odontocetes. These differences provide a structural basis for observed species differences in the depth at which lungs collapse and gas exchange ceases.
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Affiliation(s)
- Andreas Fahlman
- Woods Hole Oceanographic Institution, 266 Woods Hole Road, MS 50, Woods Hole, MA 02543, USA.
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Podowski M, Calvi C, Metzger S, Misono K, Poonyagariyagorn H, Lopez-Mercado A, Ku T, Lauer T, McGrath-Morrow S, Berger A, Cheadle C, Tuder R, Dietz HC, Mitzner W, Wise R, Neptune E. Angiotensin receptor blockade attenuates cigarette smoke-induced lung injury and rescues lung architecture in mice. J Clin Invest 2011; 122:229-40. [PMID: 22182843 DOI: 10.1172/jci46215] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 11/09/2011] [Indexed: 01/24/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no disease-altering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β-specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β-targeted therapies for patients with COPD.
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Affiliation(s)
- Megan Podowski
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Bertok S, Wilson MR, Morley PJ, de Wildt R, Bayliffe A, Takata M. Selective inhibition of intra-alveolar p55 TNF receptor attenuates ventilator-induced lung injury. Thorax 2011; 67:244-51. [PMID: 22156959 PMCID: PMC3282043 DOI: 10.1136/thoraxjnl-2011-200590] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background Tumour necrosis factor (TNF) is upregulated in the alveolar space early in the course of ventilator-induced lung injury (VILI). Studies in genetically modified mice indicate that the two TNF receptors play opposing roles during injurious high-stretch mechanical ventilation, with p55 promoting but p75 preventing pulmonary oedema. Aim To investigate the effects of selective inhibition of intra-alveolar p55 TNF receptor on pulmonary oedema and inflammation during ventilator-induced lung injury using a newly developed domain antibody. Methods Anaesthetised mice were ventilated with high tidal volume and given an intratracheal bolus of p55-specific domain antibody or anti-TNF monoclonal antibody (‘pure’ VILI model). As a model of enhanced inflammation, a subclinical dose of lipopolysaccharide (LPS) was included in the intratracheal antibody bolus (LPS+VILI model). Development of lung injury was assessed by respiratory mechanics and blood gases and protein levels in lavage fluid. Flow cytometry was used to determine leucocyte recruitment and alveolar macrophage activation, while lavage fluid cytokines were assessed by ELISA. Results The ventilation protocol produced deteriorations in respiratory mechanics and gas exchange with increased lavage fluid protein levels in the two models. The p55-specific domain antibody substantially attenuated all of these changes in the ‘pure’ VILI model, while anti-TNF antibody was ineffective. In the LPS+VILI model, p55 blockade prevented deteriorations in respiratory mechanics and oxygenation and significantly decreased neutrophil recruitment, expression of intercellular adhesion molecule 1 on alveolar macrophages, and interleukin 6 and monocyte chemotactic protein 1 levels in lavage fluid. Conclusions Selective inhibition of intra-alveolar p55 TNF receptor signalling by domain antibodies may open new therapeutic approaches for ventilated patients with acute lung injury.
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Affiliation(s)
- Szabolcs Bertok
- Section of Anaesthetics, Pain Medicine and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK
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Abstract
Major advances in respiratory mechanics occurred primarily in the latter half of the 20th century, and this is when much of our current understanding was secured. The earliest and ancient investigations involving respiratory physiology and mechanics were frequently done in conjunction with other scientific activities and often lacked the ability to make quantitative measurements. This situation changed rapidly in the 20th century, and this relatively recent history of lung mechanics has been greatly influenced by critical technological advances and applications, which have made quantitative experimental testing of ideas possible. From the spirometer of Hutchinson, to the pneumotachograph of Fleisch, to the measurement of esophageal pressure, to the use of the Wilhelmy balance by Clements, and to the unassuming strain gauges for measuring pressure and rapid paper and electronic chart recorders, these enabling devices have generated numerous quantitative experimental studies with greatly increased physiologic understanding and validation of mechanistic theories of lung function in health and disease.
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Affiliation(s)
- Wayne Mitzner
- The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
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40
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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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McGrath-Morrow SA, Lauer T, Collaco JM, Yee M, O'Reilly M, Mitzner W, Neptune E, Wise R, Biswal S. Neonatal hyperoxia contributes additively to cigarette smoke-induced chronic obstructive pulmonary disease changes in adult mice. Am J Respir Cell Mol Biol 2011; 45:610-6. [PMID: 21239606 PMCID: PMC3175575 DOI: 10.1165/rcmb.2010-0259oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 01/03/2011] [Indexed: 11/24/2022] Open
Abstract
The extent by which early postnatal lung injury contributes to the development of chronic obstructive pulmonary disease (COPD) in the adult is unclear. We hypothesized that exposure to hyperoxia during early postnatal life can augment lung changes caused by adult chronic cigarette smoke (CS) exposure. C57BL/6J mice (1 d old) were exposed to hyperoxia (O(2)) for 5 days. At 1 month of age, half of the O(2)-exposed mice and half of the control mice were placed in a CS chamber for 6 months. After exposure to CS, mice underwent quasi-static pressure-volume curve and mean chord length measurements; quantification of pro-Sp-c expression; and measurement of lung IL-8/ KC, CXCR2/IL8Rα, TNF-α, and IL-6 mRNA by real-time PCR. Adult mice exposed to O(2)+CS had significantly larger chord length measurements (P < 0.02) and lung volumes at 35 cm H(2)O (P < 0.05) compared with all other groups. They also had significantly less pro-Sp-c protein and surfactant protein C mRNA expression (P < 0.003). Mice exposed to O(2)+CS and CS-only mice had significantly higher lung resistance and longer mean time constants (P < 0.01), significantly more inflammatory cells in the bronchoalveolar lavage fluid (P < 0.03), and significantly higher levels of lung CXCR2/IL8Rα mRNA compared with mice not exposed to smoke (P < 0.02). We conclude that exposure to early postnatal hyperoxia contributed additively to CS-induced COPD changes in adult mice. These results may be relevant to a growing population of preterm children who sustained lung injury in the newborn period and may be exposed to CS in later life.
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Affiliation(s)
- Sharon A McGrath-Morrow
- Department of Pediatrics, Division of Pediatric Pulmonary, Suite 3029, 200 N. Wolfe St. Baltimore, MD 21287-2533, USA.
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McGrath-Morrow S, Malhotra D, Lauer T, Collaco JM, Mitzner W, Neptune E, Wise R, Biswal S. Exposure to neonatal cigarette smoke causes durable lung changes but does not potentiate cigarette smoke-induced chronic obstructive pulmonary disease in adult mice. Exp Lung Res 2011; 37:354-63. [PMID: 21649527 DOI: 10.3109/01902148.2011.577268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The impact of early childhood cigarette smoke (CS) exposure on CS-induced chronic obstructive pulmonary disease (COPD) is unknown. This study was performed to evaluate the individual and combined effects of neonatal and adult CS exposure on lung structure, function, and gene expression in adult mice. To model a childhood CS exposure, neonatal C57/B6 mice were exposed to 14 days of CS (Neo CS). At 10 weeks of age, Neo CS and control mice were exposed to 4 months of CS. Pulmonary function tests, bronchoalveolar lavage, and lung morphometry were measured and gene expression profiling was performed on lung tissue. Mean chord lengths and lung volumes were increased in neonatal and/or adult CS-exposed mice. Differences in immune, cornified envelope protein, muscle, and erythrocyte genes were found in CS-exposed lung. Neonatal CS exposure caused durable structural and functional changes in the adult lung but did not potentiate CS-induced COPD changes. Cornified envelope protein gene expression was decreased in all CS-exposed mice, whereas myosin and erythrocyte gene expression was increased in mice exposed to both neonatal and adult CS, suggesting an adaptive response. Additional studies may be warranted to determine the utility of these genes as biomarkers of respiratory outcomes.
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Affiliation(s)
- Sharon McGrath-Morrow
- Division of Pediatric Pulmonary, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland 21287-2533, USA.
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Dorr AD, Wilson MR, Wakabayashi K, Waite AC, Patel BV, van Rooijen N, O'Dea KP, Takata M. Sources of alveolar soluble TNF receptors during acute lung injury of different etiologies. J Appl Physiol (1985) 2011; 111:177-84. [PMID: 21512145 DOI: 10.1152/japplphysiol.00007.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Elevated soluble tumor necrosis factor-α receptor (sTNFR) levels in bronchoalveolar lavage fluid (BALF) are associated with poor patient outcome in acute lung injury (ALI). The mechanisms underlying these increases are unknown, but it is possible that pulmonary inflammation and increased alveolar epithelial permeability may individually contribute. We investigated mechanisms of elevated BALF sTNFRs in two in vivo mouse models of ALI. Anesthetized mice were challenged with intratracheal lipopolysaccharide or subjected to injurious mechanical ventilation. Lipopolysaccharide instillation produced acute intra-alveolar inflammation, but minimal alveolar epithelial permeability changes, with increased BALF sTNFR p75, but not p55. Increased p75 levels were markedly attenuated by alveolar macrophage depletion. In contrast, injurious ventilation induced substantial alveolar epithelial permeability, with increased BALF p75 and p55, which strongly correlated with total protein. BALF sTNFRs were not increased in isolated buffer-perfused lungs (devoid of circulating sTNFRs) subjected to injurious ventilation. These results suggest that lipopolysaccharide-induced intra-alveolar inflammation upregulates alveolar macrophage-mediated production of sTNFR p75, whereas enhanced alveolar epithelial permeability following mechanical ventilation leads to increased BALF p75 and p55 via plasma leakage. These data provide new insights into differential regulation of intra-alveolar sTNFR levels during ALI and may suggest sTNFRs as potential markers for evaluating the pathophysiology of ALI.
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Affiliation(s)
- Anthony D Dorr
- Section of Anaesthetics, Pain Medicine, and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Rd., London SW10 9NH, UK
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Wang W, Nguyen NM, Yablonskiy DA, Sukstanskii AL, Osmanagic E, Atkinson JJ, Conradi MS, Woods JC. Imaging lung microstructure in mice with hyperpolarized 3He diffusion MRI. Magn Reson Med 2010; 65:620-6. [PMID: 21337400 DOI: 10.1002/mrm.22737] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 10/20/2010] [Accepted: 10/27/2010] [Indexed: 11/11/2022]
Abstract
Quantitative measurement of lung microstructure is of great significance in assessment of pulmonary disease, particularly in the earliest stages. The technique for MRI-based 3He lung morphometry was previously developed and validated for human lungs, and was recently extended to ex vivo mouse lungs. The technique yields accurate, quantitative information about the microstructure and geometry of acinar airways. In this study, the 3He lung morphometry technique is successfully implemented for in vivo studies of mice. Results indicate excellent agreement between in vivo morphometry via 3He MRI and microscopic morphometry after sacrifice. This opens up new avenues for application of the technique as a precise, noninvasive, in vivo biomarker of changes in lung microstructure, within various mouse models of lung disease.
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Affiliation(s)
- Wei Wang
- Department of Physics, Washington University, St. Louis, Missouri 63110, USA
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45
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Reinke C, Bevans-Fonti S, Grigoryev DN, Drager LF, Myers AC, Wise RA, Schwartz AR, Mitzner W, Polotsky VY. Chronic intermittent hypoxia induces lung growth in adult mice. Am J Physiol Lung Cell Mol Physiol 2010; 300:L266-73. [PMID: 21131398 DOI: 10.1152/ajplung.00239.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Obstructive sleep apnea (OSA) increases cardiovascular morbidity and mortality, which have been attributed to intermittent hypoxia (IH). The effects of IH on lung structure and function are unknown. We used a mouse model of chronic IH, which mimics the O(2) profile in patients with OSA. We exposed adult C57BL/6J mice to 3 mo of IH with a fraction of inspired oxygen (F(I)(O(2))) nadir of 5% 60 times/h during the 12-h light phase. Control mice were exposed to room air. Lung volumes were measured by quasistatic pressure-volume (PV) curves under anesthesia and by water displacement postmortem. Lungs were processed for morphometry, and the mean airspace chord length (Lm) and alveolar surface area were determined. Lung tissue was stained for markers of proliferation (proliferating cell nuclear antigen), apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling), and type II alveolar epithelial cells (surfactant protein C). Gene microarrays were performed, and results were validated by real-time PCR. IH increased lung volumes by both PV curves (air vs. IH, 1.16 vs. 1.44 ml, P < 0.0001) and water displacement (P < 0.01) without changes in Lm, suggesting that IH increased the alveolar surface area. IH induced a 60% increase in cellular proliferation, but the number of proliferating type II alveolocytes tripled. There was no increase in apoptosis. IH upregulated pathways of cellular movement and cellular growth and development, including key developmental genes vascular endothelial growth factor A and platelet-derived growth factor B. We conclude that IH increases alveolar surface area by stimulating lung growth in adult mice.
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Affiliation(s)
- Christian Reinke
- Department of Medicine, Div. of Pulmonary Medicine, Johns Hopkins University, Baltimore, MD, USA.
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Thiesse J, Namati E, Sieren JC, Smith AR, Reinhardt JM, Hoffman EA, McLennan G. Lung structure phenotype variation in inbred mouse strains revealed through in vivo micro-CT imaging. J Appl Physiol (1985) 2010; 109:1960-8. [PMID: 20671036 PMCID: PMC3006419 DOI: 10.1152/japplphysiol.01322.2009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 07/26/2010] [Indexed: 11/22/2022] Open
Abstract
Within pulmonary research, the development of mouse models has provided insight into disease development, progression, and treatment. Structural phenotypes of the lung in healthy inbred mouse strains are necessary for comparison to disease models. To date, progress in the assessment of lung function in these small animals using whole lung function tests has been made. However, assessment of in vivo lung structure of inbred mouse strains has yet to be well defined. Therefore, the link between the structure and function phenotypes is still unclear. With advancements in small animal imaging it is now possible to investigate lung structures such as the central and peripheral airways, whole lung, and lobar volumes of mice in vivo, through the use of micro-CT imaging. In this study, we performed in vivo micro-CT imaging of the C57BL/6, A/J, and BALB/c mouse strains using the intermittent iso-pressure breath hold (IIBH) technique. The resulting high-resolution images were used to extract lung structure phenotypes. The three-dimensional lobar structures and airways were defined and a meaningful mouse airway nomenclature was developed. In addition, using these techniques we have uncovered significant differences in the airway structures between inbred mouse strains in vivo.
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Affiliation(s)
- Jacqueline Thiesse
- Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA
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Osmanagic E, Sukstanskii AL, Quirk JD, Woods JC, Pierce RA, Conradi MS, Weibel ER, Yablonskiy DA. Quantitative assessment of lung microstructure in healthy mice using an MR-based 3He lung morphometry technique. J Appl Physiol (1985) 2010; 109:1592-9. [PMID: 20798272 DOI: 10.1152/japplphysiol.00736.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The recently developed technique of lung morphometry using hyperpolarized (3)He diffusion magnetic resonance (MR) (Yablonskiy DA, Sukstanskii AL, Woods JC, Gierada DS, Quirk JD, Hogg JC, Cooper JD, Conradi MS. J Appl Physiol 107: 1258-1265, 2009) permits in vivo study of lung microstructure at the alveolar level. Originally proposed for human lungs, it also has the potential to study small animals. The technique relies on theoretical developments in the area of gas diffusion in lungs linking the diffusion attenuated MR signal to the lung microstructure. To adapt this technique to small animals, certain modifications in MR protocol and data analysis are required, reflecting the smaller size of mouse alveoli and acinar airways. This is the subject of the present paper. Herein, we established empirical relationships relating diffusion measurements to geometrical parameters of lung acinar airways with dimensions typical for mice and rats by using simulations of diffusion in the airways. We have also adjusted the MR protocol to acquire data with much shorter diffusion times compared with humans to accommodate the substantially smaller acinar airway length. We apply this technique to study mouse lungs ex vivo. Our MR-based measurements yield mean values of lung surface-to-volume ratio of 670 cm(-1), alveolar density of 3,200 per mm(3), alveolar depth of 55 μm, and mean chord length of 62 μm, all consistent with published data obtained histologically in mice by unbiased methods. The proposed technique can be used for in vivo experiments, opening a door for longitudinal studies of lung morphometry in mice and other small animals.
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Affiliation(s)
- E Osmanagic
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
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Cannizzaro V, Berry LJ, Nicholls PK, Zosky GR, Turner DJ, Hantos Z, Sly PD. Lung volume recruitment maneuvers and respiratory system mechanics in mechanically ventilated mice. Respir Physiol Neurobiol 2009; 169:243-51. [PMID: 19788941 DOI: 10.1016/j.resp.2009.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 09/19/2009] [Accepted: 09/23/2009] [Indexed: 11/29/2022]
Abstract
The study aim was to establish how recruitment maneuvers (RMs) influence lung mechanics and to determine whether RMs produce lung injury. Healthy BALB/c mice were allocated to receive positive end-expiratory pressure (PEEP) at 2 or 6 cmH(2)O and volume- (20 or 40 mL/kg) or pressure-controlled (25 cmH(2)O) RMs every 5 or 75 min for 150 min. The low-frequency forced oscillation technique was used to measure respiratory input impedance. Large RMs resulting in peak airway opening pressures (P(ao))>30 cmH(2)O did not increase inflammatory response or affect transcutaneous oxygen saturation but significantly lowered airway resistance, tissue damping and tissue elastance; the latter changes are likely associated with the bimodal pressure-volume behavior observed in mice. PEEP increase alone and application of RMs producing peak P(ao) below 25 cmH(2)O did not prevent or reverse changes in lung mechanics; whereas frequent application of substantial RMs on top of elevated PEEP levels produced stable lung mechanics without signs of lung injury.
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Affiliation(s)
- Vincenzo Cannizzaro
- Division of Clinical Sciences, Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, Australia
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Parameswaran H, Bartolák-Suki E, Hamakawa H, Majumdar A, Allen PG, Suki B. Three-dimensional measurement of alveolar airspace volumes in normal and emphysematous lungs using micro-CT. J Appl Physiol (1985) 2009; 107:583-92. [PMID: 19541732 DOI: 10.1152/japplphysiol.91227.2008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In pulmonary emphysema, the alveolar structure progressively breaks down via a three-dimensional (3D) process that leads to airspace enlargement. The characterization of such structural changes has, however, been based on measurements from two-dimensional (2D) tissue sections or estimates of 3D structure from 2D measurements. In this study, we developed a novel silver staining method for visualizing tissue structure in 3D using micro-computed tomographic (CT) imaging, which showed that at 30 cmH20 fixing pressure, the mean alveolar airspace volume increased from 0.12 nl in normal mice to 0.44 nl and 2.14 nl in emphysematous mice, respectively, at 7 and 14 days following elastase-induced injury. We also assessed tissue structure in 2D using laser scanning confocal microscopy. The mean of the equivalent diameters of the alveolar airspaces was lower in 2D compared with 3D, while its variance was higher in 2D than in 3D in all groups. However, statistical comparisons of alveolar airspace size from normal and emphysematous mice yielded similar results in 2D and 3D: compared with control, both the mean and variance of the equivalent diameters increased by 7 days after treatment. These indexes further increased from day 7 to day 14 following treatment. During the first 7 days following treatment, the relative change in SD increased at a much faster rate compared with the relative change in mean equivalent diameter. We conclude that quantifying heterogeneity in structure can provide new insight into the pathogenesis or progression of emphysema that is enhanced by improved sensitivity using 3D measurements.
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Wilson MR, O'Dea KP, Zhang D, Shearman AD, van Rooijen N, Takata M. Role of lung-marginated monocytes in an in vivo mouse model of ventilator-induced lung injury. Am J Respir Crit Care Med 2009; 179:914-22. [PMID: 19218195 DOI: 10.1164/rccm.200806-877oc] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
RATIONALE Recruited leukocytes play an important role in ventilator-induced lung injury, although studies have focused predominantly on neutrophils. Inflammatory subset Gr-1(high) monocytes are recruited to sites of inflammation and have been implicated in acute lung injury induced by systemic endotoxin. OBJECTIVES To investigate the recruitment and role of Gr-1(high) monocytes in an in vivo mouse model of ventilator-induced lung injury. METHODS Anesthetized mice were ventilated with low or high stretch. Flow cytometry was used to quantify monocyte subset margination to the lungs, and to assess their in situ cellular activation in response to mechanical stretch. To investigate monocyte involvement in lung injury progression, a two-hit model was used, with a subclinical dose of lipopolysaccharide (intraperitoneal) given 2 hours prior to high-stretch ventilation. In some animals, monocytes were depleted using intravenous clodronate liposomes. Development of lung injury was assessed in ventilated animals by peak inspiratory pressure and respiratory system mechanics. MEASUREMENTS AND MAIN RESULTS High-stretch ventilation induced significant pulmonary margination of Gr-1(high) but not Gr-1(low) monocytes compared with nonventilated mice. These monocytes displayed increased activation status, with higher CD11b (vs. nonventilated mice) and lower L-selectin expression (vs. low-stretch ventilation). Lipopolysaccharide challenge led to enhanced lung margination of Gr-1(high) monocytes and neutrophils, and sensitized the lungs to high stretch-induced pulmonary edema. Clodronate-liposome pretreatment depleted lung monocytes (but not neutrophils) and significantly attenuated lung injury. CONCLUSIONS High-stretch mechanical ventilation promotes pulmonary margination of activated Gr-1(high) monocytes, which play a role in the progression of ventilator-induced lung injury.
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Affiliation(s)
- Michael R Wilson
- Department of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea, United Kingdom
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