1
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Blaskovic S, Anagnostopoulou P, Borisova E, Schittny D, Donati Y, Haberthür D, Zhou-Suckow Z, Mall MA, Schlepütz CM, Stampanoni M, Barazzone-Argiroffo C, Schittny JC. Airspace Diameter Map-A Quantitative Measurement of All Pulmonary Airspaces to Characterize Structural Lung Diseases. Cells 2023; 12:2375. [PMID: 37830589 PMCID: PMC10571657 DOI: 10.3390/cells12192375] [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: 07/03/2023] [Revised: 08/21/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
(1) Background: Stereological estimations significantly contributed to our understanding of lung anatomy and physiology. Taking stereology fully 3-dimensional facilitates the estimation of novel parameters. (2) Methods: We developed a protocol for the analysis of all airspaces of an entire lung. It includes (i) high-resolution synchrotron radiation-based X-ray tomographic microscopy, (ii) image segmentation using the free machine-learning tool Ilastik and ImageJ, and (iii) calculation of the airspace diameter distribution using a diameter map function. To evaluate the new pipeline, lungs from adult mice with cystic fibrosis (CF)-like lung disease (βENaC-transgenic mice) or mice with elastase-induced emphysema were compared to healthy controls. (3) Results: We were able to show the distribution of airspace diameters throughout the entire lung, as well as separately for the conducting airways and the gas exchange area. In the pathobiological context, we observed an irregular widening of parenchymal airspaces in mice with CF-like lung disease and elastase-induced emphysema. Comparable results were obtained when analyzing lungs imaged with μCT, sugges-ting that our pipeline is applicable to different kinds of imaging modalities. (4) Conclusions: We conclude that the airspace diameter map is well suited for a detailed analysis of unevenly distri-buted structural alterations in chronic muco-obstructive lung diseases such as cystic fibrosis and COPD.
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Affiliation(s)
- Sanja Blaskovic
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (S.B.); (E.B.); (D.S.); (D.H.)
| | | | - Elena Borisova
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (S.B.); (E.B.); (D.S.); (D.H.)
| | - Dominik Schittny
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (S.B.); (E.B.); (D.S.); (D.H.)
| | - Yves Donati
- Department of Pediatrics, Gynecology and Obstetrics, Faculty of Medicine, University of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211 Genève, Switzerland; (Y.D.); (C.B.-A.)
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - David Haberthür
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (S.B.); (E.B.); (D.S.); (D.H.)
| | - Zhe Zhou-Suckow
- Department of Translational Pulmonology, University Hospital Heidelberg, Translational Lung Research Center (TLRC), A Member of German Center for Lung Research (DZL), 69120 Heidelberg, Germany;
| | - Marcus A. Mall
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité-Universitätsmedizin Berlin, 10115 Berlin, Germany;
- Berlin Institute of Health (BIH), Charité-Universitätsmedizin Berlin, 10115 Berlin, Germany
- German Center for Lung Research (DZL), Associated Partner Site, 10115 Berlin, Germany
| | - Christian M. Schlepütz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland; (C.M.S.); (M.S.)
| | - Marco Stampanoni
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland; (C.M.S.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8093 Zurich, Switzerland
| | - Constance Barazzone-Argiroffo
- Department of Pediatrics, Gynecology and Obstetrics, Faculty of Medicine, University of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211 Genève, Switzerland; (Y.D.); (C.B.-A.)
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Johannes C. Schittny
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (S.B.); (E.B.); (D.S.); (D.H.)
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2
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Redente EF, Kopf KW, Bahadur AN, Robichaud A, Lundblad LK, McDonald LT. Application-specific approaches to MicroCT for evaluation of mouse models of pulmonary disease. PLoS One 2023; 18:e0281452. [PMID: 36757935 PMCID: PMC9910664 DOI: 10.1371/journal.pone.0281452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/23/2023] [Indexed: 02/10/2023] Open
Abstract
The advent of micro-computed tomography (microCT) has provided significant advancement in our ability to generate clinically relevant assessments of lung health and disease in small animal models. As microCT use to generate outcomes analysis in pulmonary preclinical models has increased there have been substantial improvements in image quality and resolution, and data analysis software. However, there are limited published methods for standardized imaging and automated analysis available for investigators. Manual quantitative analysis of microCT images is complicated by the presence of inflammation and parenchymal disease. To improve the efficiency and limit user-associated bias, we have developed an automated pulmonary air and tissue segmentation (PATS) task list to segment lung air volume and lung tissue volume for quantitative analysis. We demonstrate the effective use of the PATS task list using four distinct methods for imaging, 1) in vivo respiration controlled scanning using a flexiVent, 2) longitudinal breath-gated in vivo scanning in resolving and non-resolving pulmonary disease initiated by lipopolysaccharide-, bleomycin-, and silica-exposure, 3) post-mortem imaging, and 4) ex vivo high-resolution scanning. The accuracy of the PATS task list was compared to manual segmentation. The use of these imaging techniques and automated quantification methodology across multiple models of lung injury and fibrosis demonstrates the broad applicability and adaptability of microCT to various lung diseases and small animal models and presents a significant advance in efficiency and standardization of preclinical microCT imaging and analysis for the field of pulmonary research.
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Affiliation(s)
- Elizabeth F. Redente
- Department of Pediatrics, National Jewish Health, Denver, Colorado, United States of America
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
| | - Katrina W. Kopf
- Department of Academic Affairs, National Jewish Health, Denver, Colorado, United States of America
| | - Ali N. Bahadur
- Bruker BioSpin Corporation, Billerica, Massachusetts, United States of America
| | | | | | - Lindsay T. McDonald
- Ralph H. Johnson VA Medical Center, Charleston, South Carolina, United States of America
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3
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Hoffman EA. Origins of and lessons from quantitative functional X-ray computed tomography of the lung. Br J Radiol 2022; 95:20211364. [PMID: 35193364 PMCID: PMC9153696 DOI: 10.1259/bjr.20211364] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 12/16/2022] Open
Abstract
Functional CT of the lung has emerged from quantitative CT (qCT). Structural details extracted at multiple lung volumes offer indices of function. Additionally, single volumetric images, if acquired at standardized lung volumes and body posture, can be used to model function by employing such engineering techniques as computational fluid dynamics. With the emergence of multispectral CT imaging including dual energy from energy integrating CT scanners and multienergy binning using the newly released photon counting CT technology, function is tagged via use of contrast agents. Lung disease phenotypes have previously been lumped together by the limitations of spirometry and plethysmography. QCT and its functional embodiment have been imbedded into studies seeking to characterize chronic obstructive pulmonary disease, severe asthma, interstitial lung disease and more. Reductions in radiation dose by an order of magnitude or more have been achieved. At the same time, we have seen significant increases in spatial and density resolution along with methodologic validations of extracted metrics. Together, these have allowed attention to turn towards more mild forms of disease and younger populations. In early applications, clinical CT offered anatomic details of the lung. Functional CT offers regional measures of lung mechanics, the assessment of functional small airways disease, as well as regional ventilation-perfusion matching (V/Q) and more. This paper will focus on the use of quantitative/functional CT for the non-invasive exploration of dynamic three-dimensional functioning of the breathing lung and beating heart within the unique negative pressure intrathoracic environment of the closed chest.
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Affiliation(s)
- Eric A Hoffman
- Departments of Radiology, Internal Medicine and Biomedical Engineering University of Iowa, Iowa, United States
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4
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Vogl C, Neef J, Wichmann C. Methods for multiscale structural and functional analysis of the mammalian cochlea. Mol Cell Neurosci 2022; 120:103720. [DOI: 10.1016/j.mcn.2022.103720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/13/2022] [Accepted: 03/08/2022] [Indexed: 01/11/2023] Open
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5
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Sarabia-Vallejos MA, Ayala-Jeria P, Hurtado DE. Three-Dimensional Whole-Organ Characterization of the Regional Alveolar Morphology in Normal Murine Lungs. Front Physiol 2021; 12:755468. [PMID: 34955878 PMCID: PMC8692792 DOI: 10.3389/fphys.2021.755468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 11/15/2021] [Indexed: 11/18/2022] Open
Abstract
Alveolar architecture plays a fundamental role in the processes of ventilation and perfusion in the lung. Alterations in the alveolar surface area and alveolar cavity volume constitute the pathophysiological basis of chronic respiratory diseases such as pulmonary emphysema. Previous studies based on micro-computed tomography (micro-CT) of lung samples have allowed the geometrical study of acinar units. However, our current knowledge is based on the study of a few tissue samples in random locations of the lung that do not give an account of the spatial distributions of the alveolar architecture in the whole lung. In this work, we combine micro-CT imaging and computational geometry algorithms to study the regional distribution of key morphological parameters throughout the whole lung. To this end, 3D whole-lung images of Sprague–Dawley rats are acquired using high-resolution micro-CT imaging and analyzed to estimate porosity, alveolar surface density, and surface-to-volume ratio. We assess the effect of current gold-standard dehydration methods in the preparation of lung samples and propose a fixation protocol that includes the application of a methanol-PBS solution before dehydration. Our results show that regional porosity, alveolar surface density, and surface-to-volume ratio have a uniform distribution in normal lungs, which do not seem to be affected by gravitational effects. We further show that sample fixation based on ethanol baths for dehydration introduces shrinking and affects the acinar architecture in the subpleural regions. In contrast, preparations based on the proposed dehydration protocol effectively preserve the alveolar morphology.
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Affiliation(s)
| | - Pedro Ayala-Jeria
- Department of Respiratory Diseases, School of Medicine, Center of Medical Research, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Daniel E Hurtado
- Department of Structural and Geotechnical Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.,Schools of Engineering, Medicine and Biological Sciences, Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.,Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile
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6
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Jung JW, Oh JS, Bae B, Ahn YH, Kim LW, Choi J, Kim HY, Kang HR, Lee CH. Ultra-high-resolution computed tomography shows changes in the lungs related with airway hyperresponsiveness in a murine asthma model. Sci Rep 2021; 11:17584. [PMID: 34475448 PMCID: PMC8413288 DOI: 10.1038/s41598-021-96853-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 08/09/2021] [Indexed: 11/12/2022] Open
Abstract
In vivo presentation of airway hyper-responsiveness (AHR) at the different time points of the allergic reaction is not clearly understood. The purpose of this study was to investigate how AHR manifests in the airway and the lung parenchyma in vivo following exposure to different stimuli and in the early and late phases of asthma after allergen exposure. Ovalbumin (OVA)-induced allergic asthma model was established using 6-week female BALB/c mice. Enhanced pause was measured with a non-invasive method to assess AHR. The dynamic changes of the airway and lung parenchyma were evaluated with ultra-high-resolution computed tomography (128 multi-detector, 1024 × 1024 matrix) for 10 h. While the methacholine challenge showed no grossly visible changes in the proximal airway and lung parenchyma despite provoking AHR, the OVA challenge induced significant immediate changes manifesting as peribronchial ground glass opacities, consolidations, air-trapping, and paradoxical proximal airway dilatations. After resolution of immediate response, multiple episodes of AHRs occurred with paradoxical proximal airway dilatation and peripheral air-trapping in late phase over a prolonged time period in vivo. Understanding of airflow limitation based on the structural changes of asthmatic airway would be helpful to make an appropriate drug delivery strategy for the treatment of asthma.
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Affiliation(s)
- Jae-Woo Jung
- Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, Korea.,Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jung Suk Oh
- Department of Radiology, Catholic University, Seoul St. Mary's Hospital, Seoul, Korea
| | - Boram Bae
- Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, Korea
| | - Yoon Hae Ahn
- Department of Internal Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea
| | - Lucy Wooyeon Kim
- Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, Korea
| | - Jiwoong Choi
- Department of Internal Medicine, University of Kansas School of Medicine, Kansas City, KS, USA.,Department of Bioengineering, University of Kansas, Lawrence, KS, USA
| | - Hye-Young Kim
- Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, Korea.,Laboratory of Mucosal Immunology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Hye-Ryun Kang
- Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, Korea. .,Department of Internal Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea.
| | - Chang Hyun Lee
- Department of Radiology and Institute of Radiation, Seoul National University College of Medicine, Seoul National University Hospital, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea.
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7
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Badea CT. Principles of Micro X-ray Computed Tomography. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00006-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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8
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In vivo Dynamic Phase-Contrast X-ray Imaging using a Compact Light Source. Sci Rep 2018; 8:6788. [PMID: 29717143 PMCID: PMC5931574 DOI: 10.1038/s41598-018-24763-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 04/05/2018] [Indexed: 12/14/2022] Open
Abstract
We describe the first dynamic and the first in vivo X-ray imaging studies successfully performed at a laser-undulator-based compact synchrotron light source. The X-ray properties of this source enable time-sequence propagation-based X-ray phase-contrast imaging. We focus here on non-invasive imaging for respiratory treatment development and physiological understanding. In small animals, we capture the regional delivery of respiratory treatment, and two measures of respiratory health that can reveal the effectiveness of a treatment; lung motion and mucociliary clearance. The results demonstrate the ability of this set-up to perform laboratory-based dynamic imaging, specifically in small animal models, and with the possibility of longitudinal studies.
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9
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Meyerholz DK, Sieren JC, Beck AP, Flaherty HA. Approaches to Evaluate Lung Inflammation in Translational Research. Vet Pathol 2017; 55:42-52. [PMID: 28812529 DOI: 10.1177/0300985817726117] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inflammation is a common feature in several types of lung disease and is a frequent end point to validate lung disease models, evaluate genetic or environmental impact on disease severity, or test the efficacy of new therapies. Questions relevant to a study should be defined during experimental design and techniques selected to specifically address these scientific queries. In this review, the authors focus primarily on the breadth of techniques to evaluate lung inflammation that have both clinical and preclinical applications. Stratification of approaches to assess lung inflammation can diminish weaknesses inherent to each technique, provide data validation, and increase the reproducibility of a study. Specialized techniques (eg, imaging, pathology) often require experienced personnel to collect, evaluate, and interpret the data; these experts should be active contributors to the research team through reporting of the data. Scoring of tissue lesions is a useful method to transform observational pathologic data into semiquantitative or quantitative data for statistical analysis and enhanced rigor. Each technique to evaluate lung inflammation has advantages and limitations; understanding these parameters can help identify approaches that best complement one another to increase the rigor and translational significance of data.
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Affiliation(s)
- David K Meyerholz
- 1 Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jessica C Sieren
- 2 Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,3 Department of Biomedical Engineering, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Amanda P Beck
- 4 Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Heather A Flaherty
- 5 Department of Veterinary Pathology, Iowa State University, Ames, IA, USA
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10
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Kizhakke Puliyakote AS, Vasilescu DM, Sen Sharma K, Wang G, Hoffman EA. A skeleton-tree-based approach to acinar morphometric analysis using microcomputed tomography with comparison of acini in young and old C57BL/6 mice. J Appl Physiol (1985) 2016; 120:1402-9. [PMID: 26940656 DOI: 10.1152/japplphysiol.00923.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 02/29/2016] [Indexed: 11/22/2022] Open
Abstract
We seek to establish a method using interior tomographic techniques (Xradia MicroXCT-400) for acinar morphometric analysis using the pathway center lines from micro X-ray computed tomographic (Micro-CT) images as the road map. Through the application of these techniques, we present a method to extend the atlas of murine lungs to acinar levels and present a comparison between two age groups of the C57BL/6 strain. Lungs fixed via vascular perfusion were scanned using high-resolution Micro-CT protocols. Individual acini were segmented, and skeletonized paths to alveolar sacs from the entrance to the acinus were formed. Morphometric parameters, including branch lengths, diameters, and branching angles, were generated. Six mice each, at two age groups (∼20 and ∼90 wk of age), were studied. Additive Gaussian noise (0 mean and SD 1, 2, 5, and 10) was used to test the robustness of the analytical method. Noise-based variations were within ±6 μm for branch lengths and ±5 μm for diameters. At a noise level of 10, errors increased. Branch diameters were less susceptible to noise than lengths. There was >95% center line overlap across all noise levels. The measurements obtained using the center lines as a road map were not affected by added noise. Acini from younger mice had smaller branch diameters and lengths at all generations without significant differences in branching angles. The relative distribution of volume in the alveolar ducts was similar across both age groups. The method has been demonstrated to be repeatable and robust to image noise and provides a new, nondestructive technique to assess and compare acinar morphometry quantitatively.
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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
| | | | - Kriti Sen Sharma
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; and
| | - Ge Wang
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; and 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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11
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Ashton JR, West JL, Badea CT. In vivo small animal micro-CT using nanoparticle contrast agents. Front Pharmacol 2015; 6:256. [PMID: 26581654 PMCID: PMC4631946 DOI: 10.3389/fphar.2015.00256] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/19/2015] [Indexed: 12/12/2022] Open
Abstract
Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research.
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Affiliation(s)
- Jeffrey R Ashton
- Department of Biomedical Engineering, Duke University, Durham NC, USA ; Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Durham NC, USA
| | - Jennifer L West
- Department of Biomedical Engineering, Duke University, Durham NC, USA
| | - Cristian T Badea
- Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Durham NC, USA
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12
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Lecht S, Stabler CT, Rylander AL, Chiaverelli R, Schulman ES, Marcinkiewicz C, Lelkes PI. Enhanced reseeding of decellularized rodent lungs with mouse embryonic stem cells. Biomaterials 2014; 35:3252-62. [PMID: 24439414 DOI: 10.1016/j.biomaterials.2013.12.093] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/24/2013] [Indexed: 12/23/2022]
Abstract
Repopulation of decellularized lung scaffolds (DLS) is limited due to alterations in the repertoire and ratios of the residual extracellular matrix (ECM) proteins, characterized by e.g., the retention of type I collagen and loss of glycoproteins. We hypothesized that pre-treatment of decellularized matrices with defined ECM proteins, which match the repertoire of integrin receptors expressed by the cells to be seeded (e.g., embryonic stem cells) can increase the efficacy of the reseeding process. To test this hypothesis, we first determined the integrin receptors profile of mouse embryonic stem cells (mESCs). Mouse ESCs express α3, α5, α6, α9 and β1, but not α1, α2 and α4 integrin subunits, as established by Western blotting and adhesion to laminin and fibronectin, but not to collagens type I and IV. Reseeding of DLS with mESCs was inefficient (6.9 ± 0.5%), but was significantly enhanced (2.3 ± 0.1 fold) by pre-treating the scaffolds with media conditioned by A549 human lung adenocarcinoma cells, which we found to contain ∼5 μg/ml laminin. Furthermore, pre-treatment with A549-conditioned media resulted in a significantly more uniform distribution of the seeded mESCs throughout the engineered organ as compared to untreated DLS. Our study may advance whole lung engineering by stressing the importance of matching the integrin receptor repertoire of the seeded cells and the cell binding motifs of DLS.
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Affiliation(s)
- Shimon Lecht
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA 19122, USA
| | - Collin T Stabler
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA 19122, USA
| | - Alexis L Rylander
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA 19122, USA
| | - Rachel Chiaverelli
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA 19122, USA
| | - Edward S Schulman
- Division of Pulmonary, Critical Care and Sleep Medicine, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Cezary Marcinkiewicz
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA 19122, USA
| | - Peter I Lelkes
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA 19122, USA.
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13
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Abstract
Micro-CT offers high spatial resolution of the distribution of stem cells and provides rapid reconstruction of 3D images and quantitative volumetric analysis. Together with real-time PCR analysis, micro-CT offers the possibility to obtain a quantification of the number of cells that are able to migrate from the bloodstream inside the muscular tissues. Here, we studied for the first time the kinetics of the human cells injected into the femoral artery of DMD animal model. It is fundamental to determine whether the cells disseminate and entrap only within the capillary system of downstream muscles and/or they are able to reach the non-injected muscles and other organs through blood flow. The efficient transplantation of stem cells to dystrophic-deficient muscle reinforced the utility of intra-arterial delivery of cells as a viable approach for cell-based clinical therapies of neuromuscular diseases.
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14
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Li M, Jirapatnakul A, Biancardi A, Riccio ML, Weiss RS, Reeves AP. Growth pattern analysis of murine lung neoplasms by advanced semi-automated quantification of micro-CT images. PLoS One 2013; 8:e83806. [PMID: 24376755 PMCID: PMC3871568 DOI: 10.1371/journal.pone.0083806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 11/09/2013] [Indexed: 11/30/2022] Open
Abstract
Computed tomography (CT) is a non-invasive imaging modality used to monitor human lung cancers. Typically, tumor volumes are calculated using manual or semi-automated methods that require substantial user input, and an exponential growth model is used to predict tumor growth. However, these measurement methodologies are time-consuming and can lack consistency. In addition, the availability of datasets with sequential images of the same tumor that are needed to characterize in vivo growth patterns for human lung cancers is limited due to treatment interventions and radiation exposure associated with multiple scans. In this paper, we performed micro-CT imaging of mouse lung cancers induced by overexpression of ribonucleotide reductase, a key enzyme in nucleotide biosynthesis, and developed an advanced semi-automated algorithm for efficient and accurate tumor volume measurement. Tumor volumes determined by the algorithm were first validated by comparison with results from manual methods for volume determination as well as direct physical measurements. A longitudinal study was then performed to investigate in vivo murine lung tumor growth patterns. Individual mice were imaged at least three times, with at least three weeks between scans. The tumors analyzed exhibited an exponential growth pattern, with an average doubling time of 57.08 days. The accuracy of the algorithm in the longitudinal study was also confirmed by comparing its output with manual measurements. These results suggest an exponential growth model for lung neoplasms and establish a new advanced semi-automated algorithm to measure lung tumor volume in mice that can aid efforts to improve lung cancer diagnosis and the evaluation of therapeutic responses.
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Affiliation(s)
- Minxing Li
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
| | - Artit Jirapatnakul
- School of Electrical and Computer Engineering, Cornell University, Ithaca, New York, United States of America
| | - Alberto Biancardi
- School of Electrical and Computer Engineering, Cornell University, Ithaca, New York, United States of America
| | - Mark L. Riccio
- Institute for Biotechnology and Life Science Technologies, Cornell University, Ithaca, New York, United States of America
| | - Robert S. Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
- * E-mail: (RSW); (APR)
| | - Anthony P. Reeves
- School of Electrical and Computer Engineering, Cornell University, Ithaca, New York, United States of America
- * E-mail: (RSW); (APR)
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Kumar H, Vasilescu DM, Yin Y, Hoffman EA, Tawhai MH, Lin CL. Multiscale imaging and registration-driven model for pulmonary acinar mechanics in the mouse. J Appl Physiol (1985) 2013; 114:971-8. [PMID: 23412896 DOI: 10.1152/japplphysiol.01136.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A registration-based multiscale method to obtain a deforming geometric model of mouse acinus is presented. An intact mouse lung was fixed by means of vascular perfusion at a hydrostatic inflation pressure of 20 cmH(2)O. Microcomputed tomography (μCT) scans were obtained at multiple resolutions. Substructural morphometric analysis of a complete acinus was performed by computing a surface-to-volume (S/V) ratio directly from the 3D reconstruction of the acinar geometry. A geometric similarity is observed to exist in the acinus where S/V is approximately preserved anywhere in the model. Using multiscale registration, the shape of the acinus at an elevated inflation pressure of 25 cmH(2)O is estimated. Changes in the alveolar geometry suggest that the deformation within the acinus is not isotropic. In particular, the expansion of the acinus (from 20 to 25 cmH(2)O) is accompanied by an increase in both surface area and volume in such a way that the S/V ratio is not significantly altered. The developed method forms a useful tool in registration-driven fluid and solid mechanics studies as displacement of the alveolar wall becomes available in a discrete sense.
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Affiliation(s)
- Haribalan Kumar
- Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242-1527, USA
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16
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Vasilescu DM, Klinge C, Knudsen L, Yin L, Wang G, Weibel ER, Ochs M, Hoffman EA. Stereological assessment of mouse lung parenchyma via nondestructive, multiscale micro-CT imaging validated by light microscopic histology. J Appl Physiol (1985) 2012; 114:716-24. [PMID: 23264542 DOI: 10.1152/japplphysiol.00855.2012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Quantitative assessment of the lung microstructure using standard stereological methods such as volume fractions of tissue, alveolar surface area, or number of alveoli, are essential for understanding the state of normal and diseased lung. These measures are traditionally obtained from histological sections of the lung tissue, a process that ultimately destroys the three-dimensional (3-D) anatomy of the tissue. In comparison, a novel X-ray-based imaging method that allows nondestructive sectioning and imaging of fixed lungs at multiple resolutions can overcome this limitation. Scanning of the whole lung at high resolution and subsequent regional sampling at ultrahigh resolution without physically dissecting the organ allows the application of design-based stereology for assessment of the whole lung structure. Here we validate multiple stereological estimates performed on micro-computed tomography (μCT) images by comparing them with those obtained via conventional histology on the same mouse lungs. We explore and discuss the potentials and limitations of the two approaches. Histological examination offers higher resolution and the qualitative differentiation of tissues by staining, but ultimately loses 3-D tissue relationships, whereas μCT allows for the integration of morphometric data with the spatial complexity of lung structure. However, μCT has limited resolution satisfactory for the sterological estimates presented in this study but not for differentiation of tissues. We conclude that introducing stereological methods in μCT studies adds value by providing quantitative information on internal structures while not curtailing more complex approaches to the study of lung architecture in the context of physiological or pathological studies.
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Burk LM, Lee YZ, Wait JM, Lu J, Zhou OZ. Non-contact respiration monitoring for in-vivo murine micro computed tomography: characterization and imaging applications. Phys Med Biol 2012; 57:5749-63. [PMID: 22948192 DOI: 10.1088/0031-9155/57/18/5749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A cone beam micro-CT has previously been utilized along with a pressure-tracking respiration sensor to acquire prospectively gated images of both wild-type mice and various adult murine disease models. While the pressure applied to the abdomen of the subject by this sensor is small and is generally without physiological effect, certain disease models of interest, as well as very young animals, are prone to atelectasis with added pressure, or they generate too weak a respiration signal with this method to achieve optimal prospective gating. In this work we present a new fibre-optic displacement sensor which monitors respiratory motion of a subject without requiring physical contact. The sensor outputs an analogue signal which can be used for prospective respiration gating in micro-CT imaging. The device was characterized and compared against a pneumatic air chamber pressure sensor for the imaging of adult wild-type mice. The resulting images were found to be of similar quality with respect to physiological motion blur; the quality of the respiration signal trace obtained using the non-contact sensor was comparable to that of the pressure sensor and was superior for gating purposes due to its better signal-to-noise ratio. The non-contact sensor was then used to acquire in-vivo micro-CT images of a murine model for congenital diaphragmatic hernia and of 11-day-old mouse pups. In both cases, quality CT images were successfully acquired using this new respiration sensor. Despite the presence of beam hardening artefacts arising from the presence of a fibre-optic cable in the imaging field, we believe this new technique for respiration monitoring and gating presents an opportunity for in-vivo imaging of disease models which were previously considered too delicate for established animal handling methods.
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Affiliation(s)
- Laurel M Burk
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599, USA.
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Osborn-Heaford HL, Ryan AJ, Murthy S, Racila AM, He C, Sieren JC, Spitz DR, Carter AB. Mitochondrial Rac1 GTPase import and electron transfer from cytochrome c are required for pulmonary fibrosis. J Biol Chem 2012; 287:3301-12. [PMID: 22157762 PMCID: PMC3270985 DOI: 10.1074/jbc.m111.308387] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 11/21/2011] [Indexed: 12/22/2022] Open
Abstract
The generation of reactive oxygen species, particularly H(2)O(2), from alveolar macrophages is causally related to the development of pulmonary fibrosis. Rac1, a small GTPase, is known to increase mitochondrial H(2)O(2) generation in macrophages; however, the mechanism by which this occurs is not known. This study shows that Rac1 is localized in the mitochondria of alveolar macrophages from asbestosis patients, and mitochondrial import requires the C-terminal cysteine of Rac1 (Cys-189), which is post-translationally modified by geranylgeranylation. Furthermore, H(2)O(2) generation mediated by mitochondrial Rac1 requires electron transfer from cytochrome c to a cysteine residue on Rac1 (Cys-178). Asbestos-exposed mice harboring a conditional deletion of Rac1 in macrophages demonstrated decreased oxidative stress and were significantly protected from developing pulmonary fibrosis. These observations demonstrate that mitochondrial import and direct electron transfer from cytochrome c to Rac1 modulates mitochondrial H(2)O(2) production in alveolar macrophages pulmonary fibrosis.
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Affiliation(s)
| | | | | | | | - Chao He
- Radiation Oncology, Free Radical and Radiation Biology Program, and
| | - Jessica C. Sieren
- Department of Radiology, University of Iowa Carver College of Medicine, and
| | - Douglas R. Spitz
- Radiation Oncology, Free Radical and Radiation Biology Program, and
| | - A. Brent Carter
- From the Departments of Internal Medicine and
- Radiation Oncology, Free Radical and Radiation Biology Program, and
- Human Toxicology Program, University of Iowa College of Public Health, Iowa City, Iowa 52242
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19
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Botnar RM, Makowski MR. Cardiovascular magnetic resonance imaging in small animals. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 105:227-61. [PMID: 22137434 DOI: 10.1016/b978-0-12-394596-9.00008-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Noninvasive imaging studies involving small animals are becoming increasingly important in preclinical pharmacological, genetic, and biomedical cardiovascular research. Especially small animal magnetic resonance imaging (MRI) using high field and clinical MRI systems has gained significant importance in recent years. Compared to other imaging modalities, like computer tomography, MRI can provide an excellent soft tissue contrast, which enables the characterization of different kinds of tissues without the use of contrast agents. In addition, imaging can be performed with high spatial and temporal resolution. Small animal MRI cannot only provide anatomical information about the beating murine heart; it can also provide functional and molecular information, which makes it a unique imaging modality. Compared to clinical MRI examinations in humans, small animal MRI is associated with additional challenges. These included a smaller size of all cardiovascular structures and a up to ten times higher heart rate. Dedicated small animal monitoring devices make a reliable cardiac triggering and respiratory gating feasible. MRI in combination with molecular probes enables the noninvasive imaging of biological processes at a molecular level. Different kinds of iron oxide or gadolinium-based contrast agents can be used for this purpose. Compared to other molecular imaging modalities, like single photon emission computed tomography (SPECT) and positron emission tomography (PET), MRI can also provide imaging with high spatial resolution, which is of high importance for the assessment of the cardiovascular system. The sensitivity for detection of MRI contrast agents is however lower compared to sensitivity of radiation associated techniques like PET and SPECT. This chapter is divided into the following sections: (1) "Introduction," (2) "Principals of Magnetic Resonance Imaging," (3) "MRI Systems for Preclinical Imaging and Experimental Setup," and (4) "Cardiovascular Magnetic Resonance Imaging."
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Affiliation(s)
- René M Botnar
- Division of Imaging Sciences, King's College London, London, United Kingdom
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20
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Affiliation(s)
- Erik L. Ritman
- Department of Physiology and Biomedical Engineering, Mayo Clinic, College of Medicine; Rochester, Minnesota 55905;
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21
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Vasilescu DM, Knudsen L, Ochs M, Weibel ER, Hoffman EA. Optimized murine lung preparation for detailed structural evaluation via micro-computed tomography. J Appl Physiol (1985) 2011; 112:159-66. [PMID: 21817110 DOI: 10.1152/japplphysiol.00550.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Utilizing micro-X-ray CT (μCT) imaging, we sought to generate an atlas of in vivo and intact/ex vivo lungs from normal murine strains. In vivo imaging allows visualization of parenchymal density and small airways (15-28 μm/voxel). Ex vivo imaging of the intact lung via μCT allows for improved understanding of the three-dimensional lung architecture at the alveolar level with voxel dimensions of 1-2 μm. μCT requires that air spaces remain air-filled to detect alveolar architecture while in vivo structural geometry of the lungs is maintained. To achieve these requirements, a fixation and imaging methodology that permits nondestructive whole lung ex vivo μCT imaging has been implemented and tested. After in vivo imaging, lungs from supine anesthetized C57Bl/6 mice, at 15, 20, and 25 cmH(2)O airway pressure, were fixed in situ via vascular perfusion using a two-stage flushing system while held at 20 cmH(2)O airway pressure. Extracted fixed lungs were air-dried. Whole lung volume was acquired at 1, 7, 21, and >70 days after the lungs were dried and served as validation for fixation stability. No significant shrinkage was observed: +8.95% change from in vivo to fixed lung (P = 0.12), -1.47% change from day 1 to day 7 (P = 0.07), -2.51% change from day 1 to day 21 (P = 0.05), and -4.90% change from day 1 to day 70 and thereafter (P = 0.04). μCT evaluation showed well-fixed alveoli and capillary beds correlating with histological analysis. A fixation and imaging method has been established for μCT imaging of the murine lung that allows for ex vivo morphometric analysis, representative of the in vivo lung.
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Lee YZ, Burk LM, Wang KH, Cao G, Volmer J, Lu J, Zhou O. Prospective respiratory gated carbon nanotube micro computed tomography. Acad Radiol 2011; 18:588-93. [PMID: 21377908 DOI: 10.1016/j.acra.2010.11.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 11/09/2010] [Accepted: 11/10/2010] [Indexed: 11/15/2022]
Abstract
RATIONALE AND OBJECTIVES Challenges remain in the imaging of the lungs of free-breathing mice. Although computed tomographic (CT) imaging is near optimal from a contrast perspective, the rapid respiration rate, limited temporal resolution, and inflexible x-ray pulse control of most micro-CT scanners limit their utility in pulmonary imaging. Carbon nanotubes (CNTs) have permitted the development of field emission cathodes, with rapid switching and precise pulse control. The goal of this study was to explore the utility of a CNT-based micro-CT system for application in quantitative pulmonary imaging. MATERIALS AND METHODS Twelve CB57/B6 mice were imaged during peak inspiration and end-exhalation using the CNT micro-CT system. The respiratory trace was derived from a sensor placed underneath the abdomen of the animal. Animals were allowed to breathe freely during the imaging under isoflurane anesthesia. Images were reconstructed using isotropic voxels of 77-μm resolution (50 kVp, 400 projections, 30-ms x-ray pulse). Lung volumes were measured with region-growing techniques and thresholds derived from the surrounding air and soft tissues. Basic functional parameters, including tidal volume, functional reserve capacity and minute volume, were also calculated. RESULTS The average scan time was 13.4 ± 1.8 minutes for each phase of the respiratory cycle. Mean lung volumes at peak inspiration and end-expiration were 0.23 ± 0.026 and 0.11 ± 0.024 mL, respectively. The average minute volume was 11.93 ± 2.64 mL/min. CONCLUSIONS The results of this study demonstrate the utility of a CNT-based micro-CT system in acquiring prospectively gated images from free-breathing mice for obtaining physiologic data. This technique provides an alternative to breath-hold techniques requiring intubation and offers greater dose efficiency than retrospective gating techniques.
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Affiliation(s)
- Yueh Z Lee
- Department of Radiology, University of North Carolina, Chapel Hill, 27599, USA.
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23
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Roller J, Laschke MW, Tschernig T, Schramm R, Veith NT, Thorlacius H, Menger MD. How to detect a dwarf: in vivo imaging of nanoparticles in the lung. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2011; 7:753-62. [PMID: 21419874 DOI: 10.1016/j.nano.2011.02.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 02/10/2011] [Accepted: 02/24/2011] [Indexed: 11/30/2022]
Abstract
UNLABELLED Nanotechnology is a rapidly developing field in science and industry. The exposure to nanoparticles (NPs) will steadily grow in the future and there is thus an urgent need to study potential impacts of the interaction between NPs and the human body. The respiratory tract is the route of entry for all accidentally inhaled NPs. Moreover, NPs may intentionally be delivered into the lung as contrast agents and drug delivery systems. The present review provides an overview of currently used techniques for the in vivo imaging of NPs in the lung, including x-ray imaging, computed tomography, gamma camera imaging, positron emission tomography, magnetic resonance imaging, near-infrared imaging, and intravital fluorescence microscopy. Studies based on these techniques may contribute to the development of novel NP-based drug delivery systems and contrast agents. In addition, they may provide completely new insights into nanotoxicological processes. FROM THE CLINICAL EDITOR Nanoparticles are rapidly gaining ground in various therapeutic and diagnostic applications. This review provides an overview of current in vivo imaging techniques of NPs in the lung, including x-ray, CT, gamma camera imaging, PET, MRI, near-infrared imaging, and intravital fluorescence microscopy, aiding the development of novel NP-based techniques and nanotoxicology.
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Affiliation(s)
- Jonas Roller
- Institute for Clinical & Experimental Surgery, University of Saarland, Homburg/Saar, Germany.
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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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25
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Namati E, Thiesse J, Sieren JC, Ross A, Hoffman EA, McLennan G. Longitudinal assessment of lung cancer progression in the mouse using in vivo micro-CT imaging. Med Phys 2010; 37:4793-805. [PMID: 20964199 DOI: 10.1118/1.3476454] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Small animal micro-CT imaging is being used increasingly in preclinical biomedical research to provide phenotypic descriptions of genomic models. Most of this imaging is coincident with animal death and is used to show the extent of disease as an end point. Longitudinal imaging overcomes the limitation of single time-point imaging because it enables tracking of the natural history of disease and provides qualitative and, where possible, quantitative assessments of the effects of an intervention. The pulmonary system is affected by many disease conditions, such as lung cancer, chronic obstructive pulmonary disease, asthma, and granulomatous disorders. Noninvasive imaging can accurately assess the lung phenotype within the living animal, evaluating not only global lung measures, but also regional pathology. However, imaging the lung in the living animal is complicated by rapid respiratory motion, which leads to image based artifacts. Furthermore, no standard mouse lung imaging protocols exist for longitudinal assessment, with each group needing to develop their own systematic approach. METHODS In this article, the authors present an outline for performing longitudinal breath-hold gated micro-CT imaging for the assessment of lung nodules in a mouse model of lung cancer. The authors describe modifications to the previously published intermittent isopressure breath-hold technique including a new animal preparation and anesthesia protocol, implementation of a ring artifact reduction, variable scanner geometry, and polynomial beam hardening correction. In addition, the authors describe a multitime-point data set registration and tumor labeling and tracking strategy. RESULTS In vivo micro-CT data sets were acquired at months 2, 3, and 4 posturethane administration in cancer mice (n = 5) and simultaneously in control mice (n = 3). 137 unique lung nodules were identified from the cancer mice while no nodules were detected in the control mice. A total of 411 nodules were segmented and labeled over the three time-points. Lung nodule metrics including RECIST, Ortho, WHO, and 3D volume were determined and extracted. A tumor incidence rate of 30.44 +/- 1.93 SEM for n = 5 was found with identification of nodules as small as 0.11 mm (RECIST) and as large as 1.66 mm (RECIST). In addition, the tumor growth and doubling rate between months 2-3 and 3-4 were calculated. Here, the growth rate was slightly higher in the second period based on the 3D volume data (0.12 +/- 0.13 to 0.13 +/- 0.17 microl) but significantly less based on the linear diameter metrics [RECIST (0.33 +/- 0.19 to 0.17 +/- 0.18 mm); Ortho (0.24 +/- 0.15 to 0.16 +/- 0.15 mm)], indicating the need to understand how each metric is obtained and how to correctly interpret change in tumor size. CONCLUSIONS In conclusion, micro-CT imaging provides a unique platform for in vivo longitudinal assessment of pulmonary lung cancer progression and potentially tracking of therapies at very high resolutions. The ability to evaluate the same subject over time provides for a sensitive assay that can be carried out on a smaller sample size. When integrated with image processing and analysis routines as detailed in this study, the data acquired from micro-CT imaging can now provide a very powerful assessment of pulmonary disease outcomes.
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Affiliation(s)
- Eman Namati
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA; School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide 5042, Australia.
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High-speed single-breath-hold micro-computed tomography of thoracic and abdominal structures in mice using a simplified method for intubation. J Comput Assist Tomogr 2010; 34:783-90. [PMID: 20861787 DOI: 10.1097/rct.0b013e3181e1050a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Respiratory gating with and without controlled ventilation has been applied for in vivo micro-computed tomography (micro-CT) of thoracic and abdominal structures in mice. We describe a simplified method for intubation and demonstrate its applicability for single-breath-hold micro-CT in mice. METHODS Mice (n = 10) were anesthetized, intubated, ventilated, and relaxed by intraperitoneal administration of rocuronium. Contrast-enhanced micro-CT of the complete thorax including the upper abdominal organs (80 kV; 37.5 μA; 190-degree rotation; 600 projections/20 seconds or 1200 projections/40 seconds; 39 × 39 × 50-μm voxel size) was performed with and without single-breath-hold technique. RESULTS The simplified method of intubation was fast (<1 minute) and required no special hardware in all mice. Relaxation of mice allowed prolonged single-breath-hold imaging of up to 40 seconds. Diameter of smallest identifiable lung vessels was 100 μm. CONCLUSIONS The presented simplified method for intubation in mice is fast, safe, and effective. Additional relaxation allowed high-resolution single-breath-hold micro-CT in mice.
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Artaechevarria X, Blanco D, de Biurrun G, Ceresa M, Pérez-Martín D, Bastarrika G, de Torres JP, Zulueta JJ, Montuenga LM, Ortiz-de-Solorzano C, Munoz-Barrutia A. Evaluation of micro-CT for emphysema assessment in mice: comparison with non-radiological techniques. Eur Radiol 2010; 21:954-62. [PMID: 20953986 DOI: 10.1007/s00330-010-1982-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 08/30/2010] [Accepted: 09/09/2010] [Indexed: 12/24/2022]
Abstract
OBJECTIVES To define the potential, limitations and synergies of micro-CT and other non-radiological techniques for the quantification of emphysema and related processes in mice, by performing a complete characterization of the elastase-induced emphysema model. MATERIALS AND METHODS Ninety A/J mice (45 treated and 45 controls) were studied at different time points using breath-hold gated micro-CT, functional test parameters, RT-PCR for RNA cytokine expression, Luminex technology for cytokine plasma concentration and histomorphometry. RESULTS Both histomorphometry and micro-CT imaging reflect rapid initial emphysema progression followed by steady-state development at decreasing rates. Cytokine measurements reveal an acute inflammatory response within the first 24 h that disappears after the first week. Limited systemic effect was observed based on plasma cytokine concentration. Lung compliance decreases during the acute inflammation phase and increases afterwards. CONCLUSION Histomorphometry is the most sensitive technique since it detects airspace enlargement before the other methods (1 h after treatment). Micro-CT correlates well with histology (r2 = 0.63) proving appropriate for longitudinal studies. Functional test parameters do not necessarily correlate with the extent of emphysema, as they can be influenced by acute inflammation. Finally, cytokine measurements correlate with the presence of inflammation in histology but not with emphysema.
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Affiliation(s)
- Xabier Artaechevarria
- Cancer Imaging Laboratory, Oncology Division, Center for Applied Medical Research, University of Navarra, 55 Pio XII, 31008 Pamplona, Spain.
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28
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Longitudinal study of a mouse model of chronic pulmonary inflammation using breath hold gated micro-CT. Eur Radiol 2010; 20:2600-8. [DOI: 10.1007/s00330-010-1853-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 05/26/2010] [Indexed: 10/19/2022]
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Makowski MR, Wiethoff AJ, Jansen CHP, Botnar RM. Cardiovascular MRI in small animals. Expert Rev Cardiovasc Ther 2010; 8:35-47. [PMID: 20014933 DOI: 10.1586/erc.09.126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Imaging studies of cardiovascular disease in small rodents have become a prerequisite in preclinical cardiovascular research. Transgenic and gene-knockout models of cardiovascular diseases enables the investigation of the influence of single genes or groups of genes on disease pathogenesis. In addition, experimental and genetically altered models provide valuable in vivo platforms to investigate the efficacy of novel drugs and contrast agents. Owing to the excellent soft tissue contrast, high spatial and temporal resolution, as well as the tomographic nature of MRI, anatomy and function can be assessed with unique accuracy and reproducibility. Furthermore, using novel targeted MRI contrast agents, molecular changes associated with cardiovascular disease can be investigated in the same imaging session. This review focuses on recent advances in hardware, imaging sequences and probe design.
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Affiliation(s)
- Marcus R Makowski
- Division of Imaging Sciences, King's College London, 4th Floor, Lambeth Wing, St Thomas' Hospital, London SE1 7EH, UK.
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30
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Hsia CCW, Hyde DM, Ochs M, Weibel ER. An official research policy statement of the American Thoracic Society/European Respiratory Society: standards for quantitative assessment of lung structure. Am J Respir Crit Care Med 2010; 181:394-418. [PMID: 20130146 DOI: 10.1164/rccm.200809-1522st] [Citation(s) in RCA: 677] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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31
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Artaechevarria X, Pérez-Martín D, Ceresa M, de Biurrun G, Blanco D, Montuenga LM, van Ginneken B, Ortiz-de-Solorzano C, Muñoz-Barrutia A. Airway segmentation and analysis for the study of mouse models of lung disease using micro-CT. Phys Med Biol 2009; 54:7009-24. [PMID: 19887716 DOI: 10.1088/0031-9155/54/22/017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Animal models of lung disease are gaining importance in understanding the underlying mechanisms of diseases such as emphysema and lung cancer. Micro-CT allows in vivo imaging of these models, thus permitting the study of the progression of the disease or the effect of therapeutic drugs in longitudinal studies. Automated analysis of micro-CT images can be helpful to understand the physiology of diseased lungs, especially when combined with measurements of respiratory system input impedance. In this work, we present a fast and robust murine airway segmentation and reconstruction algorithm. The algorithm is based on a propagating fast marching wavefront that, as it grows, divides the tree into segments. We devised a number of specific rules to guarantee that the front propagates only inside the airways and to avoid leaking into the parenchyma. The algorithm was tested on normal mice, a mouse model of chronic inflammation and a mouse model of emphysema. A comparison with manual segmentations of two independent observers shows that the specificity and sensitivity values of our method are comparable to the inter-observer variability, and radius measurements of the mainstem bronchi reveal significant differences between healthy and diseased mice. Combining measurements of the automatically segmented airways with the parameters of the constant phase model provides extra information on how disease affects lung function.
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Affiliation(s)
- X Artaechevarria
- Cancer Imaging Laboratory, Center for Applied Medical Research, 31008 Pamplona, Spain.
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32
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Weydert CJ, Esser AK, Mejia RA, Drake JM, Barnes JM, Henry MD. Endothelin-1 inhibits prostate cancer growth in vivo through vasoconstriction of tumor-feeding arterioles. Cancer Biol Ther 2009; 8:720-9. [PMID: 19242129 DOI: 10.4161/cbt.8.8.7922] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The vasoactive peptide endothelin-1 (ET-1) has been implicated in promoting the progression of prostate and other cancers though its precise mechanism(s)-of-action remain unclear. To better define the role of ET-1 in prostate cancer progression, we generated prostate cancer cell lines (PC-3 and 22Rv1) that express elevated levels of ET-1. As anticipated, increased ET-1 lead to modest autocrine growth stimulation of PC-3 cells in monolayer culture and increased colony formation in soft agar by both cell lines. Unexpectedly, however, metastatic colonization of 22Rv1 cells expressing elevated levels of ET-1 was reduced, as was the size of subcutaneous tumors produced by both 22Rv1- and PC-3 cells. Based on these data, we hypothesized that high levels of ET-1 may negatively impact the tumor microenvironment. We found that increased ET-1 expression did not consistently inhibit angiogenesis, indicating that this was not the cause of poor tumor growth. As an alternative explanation, we examined whether elevated ET-1 results in local vasoconstriction and thus reduces the blood supply available to the tumor. Consistent with this hypothesis, treatment of mice bearing PC-3 xenografts with a vasodilator increased tumor perfusion and partially restored tumor growth. Moreover, analysis of tumor vascular casts indicated vasoconstriction of tumor-feeding arterioles. Taken together, our data suggest that the local concentration of the ET-1 peptide is critical for determining a balance between its previously unrecognized tumor growth-suppressing activity (vasoconstriction) and known growth-promoting (mitogenesis, survival and angiogenesis) activities. These findings may have implications for the modification of current prostate cancer therapies involving ET-1.
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Affiliation(s)
- Christine J Weydert
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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Postnov AA, D'Haese PC, Neven E, De Clerck NM, Persy VP. Possibilities and limits of X-ray microtomography for in vivo and ex vivo detection of vascular calcifications. Int J Cardiovasc Imaging 2009; 25:615-24. [PMID: 19363656 DOI: 10.1007/s10554-009-9459-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 03/25/2009] [Indexed: 10/20/2022]
Abstract
In the present paper, vascular calcifications due to chronic renal failure in rats are studied by X-ray microtomography (micro-CT). Although micro-CT is traditionally used as an imaging technique, a quantitative analysis of data obtained by in vivo and ex vivo micro-CT is described and discussed. By comparison with traditional destructive methods, such as histomorphometry and atomic absorption, the detection limits for calcium were determined in living rats and in extracted aortas. micro-CT proved to be an effective non-invasive imaging technique allowing non-destructive quantification of ectopic calcifications.
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Affiliation(s)
- A A Postnov
- Laboratory of Microtomography, University of Antwerp, Universiteitsplein 1, Campus Drie Eiken, Antwerp, Belgium.
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Cao G, Lee YZ, Peng R, Liu Z, Rajaram R, Calderon-Colon X, An L, Wang P, Phan T, Sultana S, Lalush DS, Lu JP, Zhou O. A dynamic micro-CT scanner based on a carbon nanotube field emission x-ray source. Phys Med Biol 2009; 54:2323-40. [PMID: 19321922 DOI: 10.1088/0031-9155/54/8/005] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Current commercial micro-CT scanners have the capability of imaging objects ex vivo with high spatial resolution, but performing in vivo micro-CT on free-breathing small animals is still challenging because their physiological motions are non-periodic and much faster than those of humans. In this paper, we present a prototype physiologically gated micro-computed tomography (micro-CT) scanner based on a carbon nanotube field emission micro-focus x-ray source. The novel x-ray source allows x-ray pulses and imaging sequences to be readily synchronized and gated to non-periodic physiological signals from small animals. The system performance is evaluated using phantoms and sacrificed and anesthetized mice. Prospective respiratory-gated micro-CT images of anesthetized free-breathing mice were collected using this scanner at 50 ms temporal resolution and 6.2 lp mm(-1) at 10% system MTF. The high spatial and temporal resolutions of the micro-CT scanner make it well suited for high-resolution imaging of free-breathing small animals.
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Affiliation(s)
- G Cao
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599, USA.
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Kitchen MJ, Lewis RA, Morgan MJ, Wallace MJ, Siew ML, Siu KKW, Habib A, Fouras A, Yagi N, Uesugi K, Hooper SB. Dynamic measures of regional lung air volume using phase contrast x-ray imaging. Phys Med Biol 2008; 53:6065-77. [DOI: 10.1088/0031-9155/53/21/012] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Badea CT, Drangova M, Holdsworth DW, Johnson GA. In vivo small-animal imaging using micro-CT and digital subtraction angiography. Phys Med Biol 2008; 53:R319-50. [PMID: 18758005 DOI: 10.1088/0031-9155/53/19/r01] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Small-animal imaging has a critical role in phenotyping, drug discovery and in providing a basic understanding of mechanisms of disease. Translating imaging methods from humans to small animals is not an easy task. The purpose of this work is to review in vivo x-ray based small-animal imaging, with a focus on in vivo micro-computed tomography (micro-CT) and digital subtraction angiography (DSA). We present the principles, technologies, image quality parameters and types of applications. We show that both methods can be used not only to provide morphological, but also functional information, such as cardiac function estimation or perfusion. Compared to other modalities, x-ray based imaging is usually regarded as being able to provide higher throughput at lower cost and adequate resolution. The limitations are usually associated with the relatively poor contrast mechanisms and potential radiation damage due to ionizing radiation, although the use of contrast agents and careful design of studies can address these limitations. We hope that the information will effectively address how x-ray based imaging can be exploited for successful in vivo preclinical imaging.
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Affiliation(s)
- C T Badea
- Center for In Vivo Microscopy, Department of Radiology, Duke University, Durham, NC 27710, USA
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Chavarrías C, Vaquero JJ, Sisniega A, Rodríguez-Ruano A, Soto-Montenegro ML, García-Barreno P, Desco M. Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method. Phys Med Biol 2008; 53:4683-95. [DOI: 10.1088/0031-9155/53/17/015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sera T, Yokota H, Fujisaki K, Fukasaku K, Tachibana H, Uesugi K, Yagi N, Himeno R. Development of high-resolution 4Din vivo-CT for visualization of cardiac and respiratory deformations of small animals. Phys Med Biol 2008; 53:4285-301. [DOI: 10.1088/0031-9155/53/16/005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Namati E, De Ryk J, Thiesse J, Towfic Z, Hoffman E, Mclennan G. Large image microscope array for the compilation of multimodality whole organ image databases. Anat Rec (Hoboken) 2008; 290:1377-87. [PMID: 17853414 DOI: 10.1002/ar.20600] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Three-dimensional, structural and functional digital image databases have many applications in education, research, and clinical medicine. However, to date, apart from cryosectioning, there have been no reliable means to obtain whole-organ, spatially conserving histology. Our aim was to generate a system capable of acquiring high-resolution images, featuring microscopic detail that could still be spatially correlated to the whole organ. To fulfill these objectives required the construction of a system physically capable of creating very fine whole-organ sections and collecting high-magnification and resolution digital images. We therefore designed a large image microscope array (LIMA) to serially section and image entire unembedded organs while maintaining the structural integrity of the tissue. The LIMA consists of several integrated components: a novel large-blade vibrating microtome, a 1.3 megapixel peltier cooled charge-coupled device camera, a high-magnification microscope, and a three axis gantry above the microtome. A custom control program was developed to automate the entire sectioning and automated raster-scan imaging sequence. The system is capable of sectioning unembedded soft tissue down to a thickness of 40 microm at specimen dimensions of 200 x 300 mm to a total depth of 350 mm. The LIMA system has been tested on fixed lung from sheep and mice, resulting in large high-quality image data sets, with minimal distinguishable disturbance in the delicate alveolar structures.
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Affiliation(s)
- Eman Namati
- Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242, USA
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Hildebrandt IJ, Su H, Weber WA. Anesthesia and Other Considerations for in Vivo Imaging of Small Animals. ILAR J 2008; 49:17-26. [DOI: 10.1093/ilar.49.1.17] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Namati E, Thiesse J, de Ryk J, McLennan G. Alveolar dynamics during respiration: are the pores of Kohn a pathway to recruitment? Am J Respir Cell Mol Biol 2007; 38:572-8. [PMID: 18096874 DOI: 10.1165/rcmb.2007-0120oc] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The change in alveolar size and number during the full breathing cycle in mammals remains unanswered, yet these descriptors are fundamental for understanding alveolar-based diseases and for improving ventilator management. Genetic and environmental mouse models are used increasingly to evaluate the evolution of disease in the peripheral lung; however, little is known regarding alveolar structure and function in the fresh, intact lung. Therefore, we have developed an optical confocal process to evaluate alveolar dynamics in the fresh intact mouse lung and as an initial experiment, have evaluated mouse alveolar dynamics during a single respiratory cycle immediately after passive lung deflation. We observe that alveoli become smaller and more numerous at the end of inspiration, and propose that this is direct evidence for alveolar recruitment in the mouse lung. The findings reported support a new hypothesis that requires recruitable secondary (daughter) alveoli to inflate via primary (mother) alveoli rather than from a conducting airway.
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Affiliation(s)
- Eman Namati
- Internal Medicine, University of Iowa, 200 Hawkins Drive, C325 GH, Iowa City, IA 52242, USA
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