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Chan JCY, Chaban R, Chang SH, Angel LF, Montgomery RA, Pierson RN. Future of Lung Transplantation: Xenotransplantation and Bioengineering Lungs. Clin Chest Med 2023; 44:201-214. [PMID: 36774165 PMCID: PMC11078107 DOI: 10.1016/j.ccm.2022.11.003] [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] [Indexed: 02/11/2023]
Abstract
Xenotransplantation promises to alleviate the issue of donor organ shortages and to decrease waiting times for transplantation. Recent advances in genetic engineering have allowed for the creation of pigs with up to 16 genetic modifications. Several combinations of genetic modifications have been associated with extended graft survival and life-supporting function in experimental heart and kidney xenotransplants. Lung xenotransplantation carries specific challenges related to the large surface area of the lung vascular bed, its innate immune system's intrinsic hyperreactivity to perceived 'danger', and its anatomic vulnerability to airway flooding after even localized loss of alveolocapillary barrier function. This article discusses the current status of lung xenotransplantation, and challenges related to immunology, physiology, anatomy, and infection. Tissue engineering as a feasible alternative to develop a viable lung replacement solution is discussed.
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Affiliation(s)
- Justin C Y Chan
- NYU Transplant Institute, New York University, 530 1st Avenue, Suite 7R, New York, NY 10016, USA.
| | - Ryan Chaban
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA; Department of Cardiovascular Surgery, University Hospital of Johannes Gutenberg University, Langenbeckstr. 1, Bau 505, 5. OG55131 Mainz, Germany
| | - Stephanie H Chang
- NYU Transplant Institute, New York University, 530 1st Avenue, Suite 7R, New York, NY 10016, USA
| | - Luis F Angel
- NYU Transplant Institute, New York University, 530 1st Avenue, Suite 7R, New York, NY 10016, USA
| | - Robert A Montgomery
- NYU Transplant Institute, New York University, 530 1st Avenue, Suite 7R, New York, NY 10016, USA
| | - Richard N Pierson
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA
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Liu RC, Liu Y, Cai Z. Influence of the growth gradient on surface wrinkling and pattern transition in growing tubular tissues. Proc Math Phys Eng Sci 2021. [DOI: 10.1098/rspa.2021.0441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Growth-induced pattern formations in curved film-substrate structures have attracted extensive attention recently. In most existing literature, the growth tensor is assumed to be homogeneous or piecewise homogeneous. In this paper, we aim at clarifying the influence of a growth gradient on pattern formation and pattern evolution in bilayered tubular tissues under plane-strain deformation. In the framework of finite elasticity, a bifurcation condition is derived for a general material model and a generic growth function. Then we suppose that both layers are composed of neo-Hookean materials. In particular, the growth function is assumed to decay linearly either from the inner surface or from the outer surface. It is found that a gradient in the growth has a weak effect on the critical state, compared with the homogeneous growth type where both layers share the same growth factor. Furthermore, a finite-element model is built to validate the theoretical model and to investigate the post-buckling behaviours. It is found that the associated pattern transition is not controlled by the growth gradient but by the ratio of the shear modulus between two layers. Different morphologies can occur when the modulus ratio is varied. The current analysis could provide useful insight into the influence of a growth gradient on surface instabilities and suggests that a homogeneous growth field may provide a good approximation on interpreting complicated morphological formations in multiple systems.
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Affiliation(s)
- Rui-Cheng Liu
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, People's Republic of China
| | - Yang Liu
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, People's Republic of China
- Tianjin Key Laboratory of Modern Engineering Mechanics, Tianjin University, Tianjin 300350, People's Republic of China
| | - Zongxi Cai
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, People's Republic of China
- Tianjin Key Laboratory of Modern Engineering Mechanics, Tianjin University, Tianjin 300350, People's Republic of China
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Castro MGB, Varble NA, Yung RC, Wood BJ, Karanian JW, Pritchard WF. In Vivo Characterization of the Swine Airway Morphometry and Motion Based on Computed Tomographic Imaging During Respiration. J Biomech Eng 2020; 142:121009. [PMID: 34043756 PMCID: PMC7580654 DOI: 10.1115/1.4047550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/22/2020] [Indexed: 11/08/2022]
Abstract
Swine are a commonly used model in translational pulmonary research. However, in vivo airway morphometry during respiration has not been studied in extensive detail using modern imaging tools. Chest computed tomographic was performed in swine (n = 3) at multiple stages of respiration. Morphometric parameters of each airway segment at end-expiration and end-inspiration were compared as well as among matched anatomical regions (proximal and distal; ventral, lateral, and dorsal). Analysis included segment diameter, length, ellipticity, and the bifurcation angle between daughter branches. Deformation of the airway during respiration was qualitatively visualized using a point-to-point deformation map. Comparison of airway generation showed airway diameter and length were larger at end-inspiration in the fourth and seventh generations compared to end-expiration. Bifurcation angle was larger at end-inspiration compared to end-expiration. Analysis by anatomical region showed that length and bifurcation angle were larger at inspiration in the distal airway regions only. Regardless of respiratory phase, the lateral regions had larger diameters and lengths compared to the ventral and dorsal regions at similar generations and proximal regions had larger bifurcation angles. The findings that morphological changes were more prevalent in distal airways during respiration was confirmed by analysis of a deformation map. Compared to human airway models, the relative diameter may be smaller and length may be greater in swine in similar airway generations. This morphometric description of the swine airways during respiration may guide conduct of preclinical translational studies, revealing advantages and limitations of swine models for specific evaluations. Such morphometric parameters may directly determine the suitability of the swine model for the study of lung interventions, in terms of recapitulation of human morphometry dynamics.
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Affiliation(s)
- Meryll Grace B. Castro
- Center for Interventional Oncology, Radiology and Imaging Sciences, National Institutes of Health Clinical Center, 10 Center Drive, Room 3N320B, MSC 1182,Bethesda, MD 20892
| | - Nicole A. Varble
- Philips Research North America, Cambridge, MA 02141; Center for Interventional Oncology, Radiology and Imaging Sciences, National Institutes of Health Clinical Center, 10 Center Drive, Room 3N320, Bethesda, MD 20892
| | - Rex C. Yung
- School of Medicine, Johns Hopkins University, 733 N Broadway, Baltimore, MD 21205
| | - Bradford J. Wood
- Clinical Center Radiology and Imaging Sciences, Center for Interventional Oncology, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892
| | - John W. Karanian
- Center for Interventional Oncology, Radiology and Imaging Sciences, National Institutes of Health Clinical Center, 10 Center Drive, Room 3N320B, MSC 1182,Bethesda, MD 20892
| | - William F. Pritchard
- Center for Interventional Oncology, Radiology and Imaging Sciences, National Institutes of Health, 10 Center Drive, Room 3N320B, MSC 1182, Bethesda, MD 20892
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Regulation of Airway Smooth Muscle Contraction in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:381-422. [PMID: 31183836 DOI: 10.1007/978-981-13-5895-1_16] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Airway smooth muscle (ASM) extends from the trachea throughout the bronchial tree to the terminal bronchioles. In utero, spontaneous phasic contraction of fetal ASM is critical for normal lung development by regulating intraluminal fluid movement, ASM differentiation, and release of key growth factors. In contrast, phasic contraction appears to be absent in the adult lung, and regulation of tonic contraction and airflow is under neuronal and humoral control. Accumulating evidence suggests that changes in ASM responsiveness contribute to the pathophysiology of lung diseases with lifelong health impacts.Functional assessments of fetal and adult ASM and airways have defined pharmacological responses and signaling pathways that drive airway contraction and relaxation. Studies using precision-cut lung slices, in which contraction of intrapulmonary airways and ASM calcium signaling can be assessed simultaneously in situ, have been particularly informative. These combined approaches have defined the relative importance of calcium entry into ASM and calcium release from intracellular stores as drivers of spontaneous phasic contraction in utero and excitation-contraction coupling.Increased contractility of ASM in asthma contributes to airway hyperresponsiveness. Studies using animal models and human ASM and airways have characterized inflammatory and other mechanisms underlying increased reactivity to contractile agonists and reduced bronchodilator efficacy of β2-adrenoceptor agonists in severe diseases. Novel bronchodilators and the application of bronchial thermoplasty to ablate increased ASM within asthmatic airways have the potential to overcome limitations of current therapies. These approaches may directly limit excessive airway contraction to improve outcomes for difficult-to-control asthma and other chronic lung diseases.
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El biomodelo porcino en la investigación médica traslacional: del biomodelo al humano en trasplante pulmonar. ACTA ACUST UNITED AC 2019; 39:300-313. [DOI: 10.7705/biomedica.v39i3.3820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Indexed: 01/05/2023]
Abstract
Introducción. La anatomía humana y porcina son comparables. En consecuencia, el biomodelo porcino tiene el potencial de ser implementado para entrenar al profesional quirúrgico en áreas como el trasplante de órganos sólidos.Objetivo. Describir los procedimientos y hallazgos obtenidos mediante experimentos de medicina respiratoria traslacional con biomodelos porcinos realizados en un laboratorio de experimentación animal, y hacer una revisión comparativa entre el pulmón humano y el porcino.Materiales y métodos. El experimento se llevó a cabo en nueve cerdos de raza híbrida en un laboratorio de cirugía experimental. Se estudiaron la anatomía y la histología de las vías respiratorias mediante fibrobroncoscopia, biopsia bronquial y lavado broncoalveolar. El lavado broncoalveolar se estudió con citología en base líquida y se evaluó con las coloraciones de Papanicolau y hematoxilina y eosina. Se utilizaron técnicas de patología molecular, como inmunohistoquímica, citometría de flujo y microscopía electrónica. Los cerdos se sometieron a neumonectomía izquierda con posterior implante del injerto en otro cerdo experimental.Resultados. Los estudios histopatológicos y moleculares evidenciaron un predominio de macrófagos alveolares (98 %) y linfocitos T (2 %) en el lavado broncoalveolar porcino. En los estudios del parénquima pulmonar porcino se encontró tejido linfoide hiperplásico asociado a las paredes bronquiales. La microscopía electrónica evidenció linfocitos T dentro del epitelio y el diámetro de las cilias porcinas fue similar al de las humanas.Conclusiones. El biomodelo porcino es viable en la investigación traslacional para el entendimiento de la anatomía del sistema respiratorio y el entrenamiento en trasplante pulmonar. La implementación de este modelo experimental podría fortalecer los grupos que planean implementar un programa institucional de trasplante pulmonar en humanos.
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Eskandari M, Arvayo AL, Levenston ME. Mechanical properties of the airway tree: heterogeneous and anisotropic pseudoelastic and viscoelastic tissue responses. J Appl Physiol (1985) 2018; 125:878-888. [PMID: 29745796 DOI: 10.1152/japplphysiol.00090.2018] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Airway obstruction and pulmonary mechanics remain understudied despite lung disease being the third cause of death in the United States. Lack of relevant data has led computational pulmonary models to infer mechanical properties from available material data for the trachea. Additionally, the time-dependent, viscoelastic behaviors of airways have been largely overlooked, despite their potential physiological relevance and utility as metrics of tissue remodeling and disease progression. Here, we address the clear need for airway-specific material characterization to inform biophysical studies of the bronchial tree. Specimens from three airway levels (trachea, large bronchi, and small bronchi) and two orientations (axial and circumferential) were prepared from five fresh pig lungs. Uniaxial tensile tests revealed substantial heterogeneity and anisotropy. Overall, the linear pseudoelastic modulus was significantly higher axially than circumferentially (30.5 ± 3.1 vs. 8.4 ± 1.1 kPa) and significantly higher among circumferential samples for small bronchi than for the trachea and large bronchi (12.5 ± 1.9 vs. 6.0 ± 0.6 and 6.6 ± 0.9 kPa). Circumferential samples exhibited greater percent stress relaxation over 300 s than their axial counterparts (38.0 ± 1.4 vs. 23.1 ± 1.5%). Axial and circumferential trachea samples displayed greater percent stress relaxation (26.4 ± 1.6 and 42.5 ± 1.7%) than corresponding large and small bronchi. This ex vivo pseudoelastic and viscoelastic characterization reveals novel anisotropic and heterogeneous behaviors and equips us to construct airway-specific constitutive relations. Our results establish necessary fundamentals for airway mechanics, laying the groundwork for future studies to extend to clinical questions surrounding lung injury, and further directly enables computational tools for lung disease obstruction predictions. NEW & NOTEWORTHY Understanding the mechanics of the lung is necessary for investigating disease progression. Trachea mechanics comprises the vast majority of ex vivo airway tissue characterization despite distal airways being the site of disease manifestation and occlusion. Furthermore, viscoelastic studies are scarce, whereas time-dependent behaviors could be potential physiological metrics of tissue remodeling. In this study, the critical need for airway-specific material properties is addressed, reporting bronchial tree anisotropic and heterogeneous material properties.
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Affiliation(s)
- Mona Eskandari
- Department of Mechanical Engineering, University of California at Riverside , Riverside, California.,Department of Mechanical Engineering, Stanford University , Stanford, California
| | - Alberto L Arvayo
- Department of Mechanical Engineering, Stanford University , Stanford, California
| | - Marc E Levenston
- Department of Mechanical Engineering, Stanford University , Stanford, California.,Department of Bioengineering, Stanford University , Stanford, California
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7
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The use of porcine corrosion casts for teaching human anatomy. Ann Anat 2017; 213:69-77. [PMID: 28578926 DOI: 10.1016/j.aanat.2017.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 04/14/2017] [Accepted: 05/04/2017] [Indexed: 02/08/2023]
Abstract
In teaching and learning human anatomy, anatomical autopsy and prosected specimens have always been indispensable. However, alternative methods must often be used to demonstrate particularly delicate structures. Corrosion casting of porcine organs with Biodur E20® Plus is valuable for teaching and learning both gross anatomy and, uniquely, the micromorphology of cardiovascular, respiratory, digestive, and urogenital systems. Assessments of casts with a stereomicroscope and/or scanning electron microscope as well as highlighting cast structures using color coding help students to better understand how the structures that they have observed as two-dimensional images actually exist in three dimensions, and students found using the casts to be highly effective in their learning. Reconstructions of cast hollow structures from (micro-)computed tomography scans and videos facilitate detailed analyses of branching patterns and spatial arrangements in cast structures, aid in the understanding of clinically relevant structures and provide innovative visual aids. The casting protocol and teaching manual we offer can be adjusted to different technical capabilities and might also be found useful for veterinary or other biological science classes.
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8
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McLaughlin RA, Noble PB, Sampson DD. Optical coherence tomography in respiratory science and medicine: from airways to alveoli. Physiology (Bethesda) 2015; 29:369-80. [PMID: 25180266 DOI: 10.1152/physiol.00002.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Optical coherence tomography is a rapidly maturing optical imaging technology, enabling study of the in vivo structure of lung tissue at a scale of tens of micrometers. It has been used to assess the layered structure of airway walls, quantify both airway lumen caliber and compliance, and image individual alveoli. This article provides an overview of the technology and reviews its capability to provide new insights into respiratory disease.
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Affiliation(s)
- Robert A McLaughlin
- Optical & Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Australia;
| | - Peter B Noble
- School of Anatomy, Physiology & Human Biology, and Centre for Neonatal Research & Education, School of Paediatrics and Child Health, The University of Western Australia, Crawley, Australia; and
| | - David D Sampson
- Optical & Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Australia; Centre for Microscopy, Characterisation & Analysis, The University of Western Australia, Perth, Australia
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9
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Patient-Specific Airway Wall Remodeling in Chronic Lung Disease. Ann Biomed Eng 2015; 43:2538-51. [PMID: 25821112 DOI: 10.1007/s10439-015-1306-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 03/20/2015] [Indexed: 12/20/2022]
Abstract
Chronic lung disease affects more than a quarter of the adult population; yet, the mechanics of the airways are poorly understood. The pathophysiology of chronic lung disease is commonly characterized by mucosal growth and smooth muscle contraction of the airways, which initiate an inward folding of the mucosal layer and progressive airflow obstruction. Since the degree of obstruction is closely correlated with the number of folds, mucosal folding has been extensively studied in idealized circular cross sections. However, airflow obstruction has never been studied in real airway geometries; the behavior of imperfect, non-cylindrical, continuously branching airways remains unknown. Here we model the effects of chronic lung disease using the nonlinear field theories of mechanics supplemented by the theory of finite growth. We perform finite element analysis of patient-specific Y-branch segments created from magnetic resonance images. We demonstrate that the mucosal folding pattern is insensitive to the specific airway geometry, but that it critically depends on the mucosal and submucosal stiffness, thickness, and loading mechanism. Our results suggests that patient-specific airway models with inherent geometric imperfections are more sensitive to obstruction than idealized circular models. Our models help to explain the pathophysiology of airway obstruction in chronic lung disease and hold promise to improve the diagnostics and treatment of asthma, bronchitis, chronic obstructive pulmonary disease, and respiratory failure.
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10
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Ueki A, Kidoaki S. Manipulation of cell mechanotaxis by designing curvature of the elasticity boundary on hydrogel matrix. Biomaterials 2015; 41:45-52. [DOI: 10.1016/j.biomaterials.2014.11.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/29/2014] [Accepted: 11/08/2014] [Indexed: 10/24/2022]
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11
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Judge EP, Hughes JML, Egan JJ, Maguire M, Molloy EL, O'Dea S. Anatomy and bronchoscopy of the porcine lung. A model for translational respiratory medicine. Am J Respir Cell Mol Biol 2014; 51:334-43. [PMID: 24828366 DOI: 10.1165/rcmb.2013-0453tr] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The porcine model has contributed significantly to biomedical research over many decades. The similar size and anatomy of pig and human organs make this model particularly beneficial for translational research in areas such as medical device development, therapeutics and xenotransplantation. In recent years, a major limitation with the porcine model was overcome with the successful generation of gene-targeted pigs and the publication of the pig genome. As a result, the role of this model is likely to become even more important. For the respiratory medicine field, the similarities between pig and human lungs give the porcine model particular potential for advancing translational medicine. An increasing number of lung conditions are being studied and modeled in the pig. Genetically modified porcine models of cystic fibrosis have been generated that, unlike mouse models, develop lung disease similar to human cystic fibrosis. However, the scientific literature relating specifically to porcine lung anatomy and airway histology is limited and is largely restricted to veterinary literature and textbooks. Furthermore, methods for in vivo lung procedures in the pig are rarely described. The aims of this review are to collate the disparate literature on porcine lung anatomy, histology, and microbiology; to provide a comparison with the human lung; and to describe appropriate bronchoscopy procedures for the pig lungs to aid clinical researchers working in the area of translational respiratory medicine using the porcine model.
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Affiliation(s)
- Eoin P Judge
- 1 Irish National Lung and Heart Transplant Program, Mater Misericordiae University Hospital, Dublin, Ireland
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12
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Hariri LP, Applegate MB, Mino-Kenudson M, Mark EJ, Medoff BD, Luster AD, Bouma BE, Tearney GJ, Suter MJ. Volumetric optical frequency domain imaging of pulmonary pathology with precise correlation to histopathology. Chest 2013; 143:64-74. [PMID: 22459781 DOI: 10.1378/chest.11-2797] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Lung cancer is the leading cause of cancer-related mortality. Radiology and bronchoscopy techniques do not have the necessary resolution to evaluate lung lesions on the microscopic scale, which is critical for diagnosis. Bronchial biopsy specimens can be limited by sampling error and small size. Optical frequency domain imaging (OFDI) provides volumetric views of tissue microstructure at near-histologic resolution and may be useful for evaluating pulmonary lesions to increase diagnostic accuracy. Bronchoscopic OFDI has been evaluated in vivo, but a lack of correlated histopathology has limited the ability to develop accurate image interpretation criteria. METHODS We performed OFDI through two approaches (airway-centered and parenchymal imaging) in 22 ex vivo lung specimens, using tissue dye to precisely correlate imaging and histology. RESULTS OFDI of normal airway allowed visualization of epithelium, lamina propria, cartilage, and alveolar attachments. Carcinomas exhibited architectural disarray, loss of normal airway and alveolar structure, and rapid light attenuation. Squamous cell carcinomas showed nested architecture. Atypical glandular formation was appreciated in adenocarcinomas, and uniform trabecular gland formation was seen in salivary gland carcinomas. Mucinous adenocarcinomas showed alveolar wall thickening with intraalveolar mucin. Interstitial fibrosis was visualized as signal-dense tissue, with an interstitial distribution in mild interstitial fibrotic disease and a diffuse subpleural pattern with cystic space formation in usual interstitial pneumonitis. CONCLUSIONS To our knowledge, this study is the first demonstration of volumetric OFDI with precise correlation to histopathology in lung pathology. We anticipate that OFDI may play a role in assessing airway and parenchymal pathology, providing fresh insights into the volumetric features of pulmonary disease.
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Affiliation(s)
- Lida P Hariri
- Department of Pathology, Boston; Wellman Center for Photomedicine, Boston; Harvard Medical School, Cambridge
| | - Matthew B Applegate
- Pulmonary and Critical Care Unit, Boston; Wellman Center for Photomedicine, Boston
| | | | - Eugene J Mark
- Department of Pathology, Boston; Harvard Medical School, Cambridge
| | - Benjamin D Medoff
- Pulmonary and Critical Care Unit, Boston; Harvard Medical School, Cambridge
| | - Andrew D Luster
- Rheumatology, Allergy and Immunology Division, Massachusetts General Hospital, Boston; Harvard Medical School, Cambridge
| | - Brett E Bouma
- Wellman Center for Photomedicine, Boston; Harvard Medical School, Cambridge; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Guillermo J Tearney
- Department of Pathology, Boston; Wellman Center for Photomedicine, Boston; Harvard Medical School, Cambridge; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Melissa J Suter
- Pulmonary and Critical Care Unit, Boston; Wellman Center for Photomedicine, Boston; Harvard Medical School, Cambridge.
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McLaughlin RA, Yang X, Quirk BC, Lorenser D, Kirk RW, Noble PB, Sampson DD. Static and dynamic imaging of alveoli using optical coherence tomography needle probes. J Appl Physiol (1985) 2012; 113:967-74. [DOI: 10.1152/japplphysiol.00051.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Imaging of alveoli in situ has for the most part been infeasible due to the high resolution required to discern individual alveoli and limited access to alveoli beneath the lung surface. In this study, we present a novel technique to image alveoli using optical coherence tomography (OCT). We propose the use of OCT needle probes, where the distal imaging probe has been miniaturized and encased within a hypodermic needle (as small as 30-gauge, outer diameter 310 μm), allowing insertion deep within the lung tissue with minimal tissue distortion. Such probes enable imaging at a resolution of ∼12 μm within a three-dimensional cylindrical field of view with diameter ∼1.5 mm centered on the needle tip. The imaging technique is demonstrated on excised lungs from three different species: adult rats, fetal sheep, and adult pigs. OCT needle probes were used to image alveoli, small bronchioles, and blood vessels, and results were matched to histological sections. We also present the first dynamic OCT images acquired with an OCT needle probe, allowing tracking of individual alveoli during simulated cyclical lung inflation and deflation.
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Affiliation(s)
- Robert A. McLaughlin
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Xiaojie Yang
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Bryden C. Quirk
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Dirk Lorenser
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Rodney W. Kirk
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B. Noble
- Centre for Neonatal Research and Education, School of Women's and Infants' Health, University of Western Australia, Crawley, Western Australia, Australia; and
| | - David D. Sampson
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley Western Australia, Australia
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Wright D, Sharma P, Ryu MH, Rissé PA, Ngo M, Maarsingh H, Koziol-White C, Jha A, Halayko AJ, West AR. Models to study airway smooth muscle contraction in vivo, ex vivo and in vitro: implications in understanding asthma. Pulm Pharmacol Ther 2012; 26:24-36. [PMID: 22967819 DOI: 10.1016/j.pupt.2012.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/14/2012] [Accepted: 08/17/2012] [Indexed: 11/16/2022]
Abstract
Asthma is a chronic obstructive airway disease characterised by airway hyperresponsiveness (AHR) and airway wall remodelling. The effector of airway narrowing is the contraction of airway smooth muscle (ASM), yet the question of whether an inherent or acquired dysfunction in ASM contractile function plays a significant role in the disease pathophysiology remains contentious. The difficulty in determining the role of ASM lies in limitations with the models used to assess contraction. In vivo models provide a fully integrated physiological response but ASM contraction cannot be directly measured. Ex vivo and in vitro models can provide more direct assessment of ASM contraction but the loss of factors that may modulate ASM responsiveness and AHR, including interaction between multiple cell types and disruption of the mechanical environment, precludes a complete understanding of the disease process. In this review we detail key advantages of common in vivo, ex vivo and in vitro models of ASM contraction, as well as emerging tissue engineered models of ASM and whole airways. We also highlight important findings from each model with respect to the pathophysiology of asthma.
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Affiliation(s)
- David Wright
- Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, United Kingdom
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15
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Abstract
Pulmonary function testing is part of routine clinical practice in respiratory medicine. It is based around spirometry, which will remain the central measurement of lung function given its prognostic significance and its integral role in defining severity of airways disease. However, there is an increasing body of evidence from studies using new methods of lung function measurement which are providing new insights into pathophysiology of disease. This body of data is forming a basis for their future clinical role, once the economics of producing the relevant devices becomes attractive. The forced oscillation technique and multiple breath nitrogen washout are currently the most commonly used of the newer lung function techniques, which are refinements of long-established techniques. Optical coherence tomography, optical reflection, electrical impedance and vibration response imaging have arisen by development of novel devices. The recent use of these techniques is reviewed.
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Affiliation(s)
- Gregory G King
- Woolcock Institute of Medical Research, The Northern Clinical School, Sydney Medical School, University of Sydney, New South Wales, Australia.
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