101
|
Abstract
During the development of the pulmonary vasculature in the fetus, many structural and functional changes occur to prepare the lung for the transition to air breathing. The development of the pulmonary circulation is genetically controlled by an array of mitogenic factors in a temporo-spatial order. With advancing gestation, pulmonary vessels acquire increased vasoreactivity. The fetal pulmonary vasculature is exposed to a low oxygen tension environment that promotes high intrinsic myogenic tone and high vasocontractility. At birth, a dramatic reduction in pulmonary arterial pressure and resistance occurs with an increase in oxygen tension and blood flow. The striking hemodynamic differences in the pulmonary circulation of the fetus and newborn are regulated by various factors and vasoactive agents. Among them, nitric oxide, endothelin-1, and prostaglandin I2 are mainly derived from endothelial cells and exert their effects via cGMP, cAMP, and Rho kinase signaling pathways. Alterations in these signaling pathways may lead to vascular remodeling, high vasocontractility, and persistent pulmonary hypertension of the newborn.
Collapse
Affiliation(s)
- Yuansheng Gao
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China; and Department of Pediatrics, University of Illinois, College of Medicine at Chicago, Chicago, Illinois
| | - J. Usha Raj
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China; and Department of Pediatrics, University of Illinois, College of Medicine at Chicago, Chicago, Illinois
| |
Collapse
|
102
|
Litzlbauer HD, Korbel K, Kline TL, Jorgensen SM, Eaker DR, Bohle RM, Ritman EL, Langheinrich AC. Synchrotron-based micro-CT imaging of the human lung acinus. Anat Rec (Hoboken) 2010; 293:1607-14. [PMID: 20687188 DOI: 10.1002/ar.21161] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Structural data about the human lung fine structure are mainly based on stereological methods applied to serial sections. As these methods utilize 2D images, which are often not contiguous, they suffer from inaccuracies which are overcome by analysis of 3D micro-CT images of the never-sectioned specimen. The purpose of our study was to generate a complete data set of the intact three-dimensional architecture of the human acinus using high-resolution synchrotron-based micro-CT (synMCT). A human lung was inflation-fixed by formaldehyde ventilation and then scanned in a 64-slice CT over its apex to base extent. Lung samples (8-mm diameter, 10-mm height, N = 12) were punched out, stained with osmium tetroxide, and scanned using synMCT at (4 μm)(3) voxel size. The lung functional unit (acinus, N = 8) was segmented from the 3D tomographic image using an automated tree-analysis software program. Morphometric data of the lung were analyzed by ANOVA. Intra-acinar airways branching occurred over 11 generations. The mean acinar volume was 131.3 ± 29.2 mm(3) (range, 92.5-171.3 mm(3)) and the mean acinar surface was calculated with 1012 ± 26 cm(2). The airway internal diameter (starting from the bronchiolus terminalis) decreases distally from 0.66 ± 0.04 mm to 0.34 ± 0.06 mm (P < 0.001) and remains constant after the seventh generation (P < 0.5). The length of each generation ranges between 0.52 and 0.93 mm and did not show significant differences between the second and eleventh generation. The branching angle between daughter branches varies between 113-degree and 134-degree without significant differences between the generations (P < 0.3). This study demonstrates the feasibility of quantitating the 3D structure of the human acinus at the spatial resolution readily achievable using synMCT.
Collapse
Affiliation(s)
- Horst Detlef Litzlbauer
- Department of Radiology, Justus-Liebig University of Giessen and Marburg GmbH, Giessen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
103
|
Haberthür D, Hintermüller C, Marone F, Schittny JC, Stampanoni M. Radiation dose optimized lateral expansion of the field of view in synchrotron radiation X-ray tomographic microscopy. JOURNAL OF SYNCHROTRON RADIATION 2010; 17:590-599. [PMID: 20724780 PMCID: PMC2927902 DOI: 10.1107/s0909049510019618] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 05/25/2010] [Indexed: 05/29/2023]
Abstract
Volumetric data at micrometer level resolution can be acquired within a few minutes using synchrotron-radiation-based tomographic microscopy. The field of view along the rotation axis of the sample can easily be increased by stacking several tomograms, allowing the investigation of long and thin objects at high resolution. On the contrary, an extension of the field of view in the perpendicular direction is non-trivial. This paper presents an acquisition protocol which increases the field of view of the tomographic dataset perpendicular to its rotation axis. The acquisition protocol can be tuned as a function of the reconstruction quality and scanning time. Since the scanning time is proportional to the radiation dose imparted to the sample, this method can be used to increase the field of view of tomographic microscopy instruments while optimizing the radiation dose for radiation-sensitive samples and keeping the quality of the tomographic dataset on the required level. This approach, dubbed wide-field synchrotron radiation tomographic microscopy, can increase the lateral field of view up to five times. The method has been successfully applied for the three-dimensional imaging of entire rat lung acini with a diameter of 4.1 mm at a voxel size of 1.48 microm.
Collapse
Affiliation(s)
| | - Christoph Hintermüller
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
- Institute of Biomedical Engineering, University and ETH Zürich, Switzerland
| | - Federica Marone
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | | | - Marco Stampanoni
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
- Institute of Biomedical Engineering, University and ETH Zürich, Switzerland
| |
Collapse
|
104
|
Visualization of respiratory flows from 3D reconstructed alveolar airspaces using X-ray tomographic microscopy. J Vis (Tokyo) 2010. [DOI: 10.1007/s12650-010-0043-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
105
|
|
106
|
Masood A, Yi M, Lau M, Belcastro R, Shek S, Pan J, Kantores C, McNamara PJ, Kavanagh BP, Belik J, Jankov RP, Tanswell AK. Therapeutic effects of hypercapnia on chronic lung injury and vascular remodeling in neonatal rats. Am J Physiol Lung Cell Mol Physiol 2009; 297:L920-30. [DOI: 10.1152/ajplung.00139.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Permissive hypercapnia, achieved using low tidal volume ventilation, has been an effective protective strategy in patients with acute respiratory distress syndrome. To date, no such protective effect has been demonstrated for the chronic neonatal lung injury, bronchopulmonary dysplasia. The objective of our study was to determine whether evolving chronic neonatal lung injury, using a rat model, is resistant to the beneficial effects of hypercapnia or simply requires a less conservative approach to hypercapnia than that applied clinically to date. Neonatal rats inhaled air or 60% O2 for 14 days with or without 5.5% CO2. Lung parenchymal neutrophil and macrophage numbers were significantly increased by hyperoxia alone, which was associated with interstitial thickening and reduced secondary crest formation. The phagocyte influx, interstitial thickening, and impaired alveolar formation were significantly attenuated by concurrent hypercapnia. Hyperoxic pups that received 5.5% CO2 had a significant increase in alveolar number relative to air-exposed pups. Increased tyrosine nitration, a footprint for peroxynitrite-mediated reactions, arteriolar medial wall thickening, and both reduced small peripheral pulmonary vessel number and VEGF and angiopoietin-1 (Ang-1) expression, which were observed with hyperoxia, was attenuated by concurrent hypercapnia. We conclude that evolving chronic neonatal lung injury in a rat model is responsive to the beneficial effects of hypercapnia. Inhaled 5.5% CO2 provided a significant degree of protection against parenchymal and vascular injury in an animal model of chronic neonatal lung injury likely due, at least in part, to its inhibition of a phagocyte influx.
Collapse
Affiliation(s)
- Azhar Masood
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Man Yi
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Mandy Lau
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Rosetta Belcastro
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
| | - Samuel Shek
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
| | - Jingyi Pan
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
| | - Crystal Kantores
- Clinical Integrative Biology, Sunnybrook Research Institute; and
| | - Patrick J. McNamara
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Paediatrics, and
| | - Brian P. Kavanagh
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Departments of 4Anaesthesia,
- Critical Care Medicine,
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jaques Belik
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Paediatrics, and
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Robert P. Jankov
- Clinical Integrative Biology, Sunnybrook Research Institute; and
- Paediatrics, and
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - A. Keith Tanswell
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Paediatrics, and
- Physiology, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
107
|
Johnson BH, Yi M, Masood A, Belcastro R, Li J, Shek S, Kantores C, Jankov RP, Tanswell AK. A critical role for the IL-1 receptor in lung injury induced in neonatal rats by 60% O2. Pediatr Res 2009; 66:260-5. [PMID: 19542903 DOI: 10.1203/pdr.0b013e3181b1bcd2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
IL-1 beta, a proinflammatory cytokine, may contribute to the development of the chronic neonatal lung injury, bronchopulmonary dysplasia. Chronic neonatal lung injury was induced in rats, by exposure to 60% O2 for 14 d from birth, to determine whether pulmonary IL-1 expression was up-regulated and, if so, whether a daily s.c. IL-1 receptor antagonist injections would be protective. Exposure to 60% O2 for 14 d caused pulmonary neutrophil and macrophage influx, increased tissue fraction and tyrosine nitration, reduced VEGF-A and angiopoietin-1 expression, and reduced small vessel (20-65 microm) and alveolar numbers. Lung IL-1 alpha and -1 beta contents were increased after a 4-d exposure to 60% O2. IL-1 receptor antagonist treatment attenuated the 60% O2-dependent neutrophil influx, the increased tissue fraction, and the reduced alveolar number. Treatment did not restore VEGF-A or angiopoietin-1 expression and only partially attenuated the reduced vessel number in 60% O2-exposed pups. It also caused a paradoxical increase in macrophage influx and a reduction in small vessels in air-exposed pups. We conclude that antagonism of IL-1-mediated effects can, in major part, protect against lung injury in a rat model of 60% O2-induced chronic neonatal lung injury.
Collapse
Affiliation(s)
- Ben-Hur Johnson
- Department of Paediatrics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
108
|
Mitani A, Nagase T, Fukuchi K, Aburatani H, Makita R, Kurihara H. Transcriptional coactivator with PDZ-binding motif is essential for normal alveolarization in mice. Am J Respir Crit Care Med 2009; 180:326-38. [PMID: 19498055 DOI: 10.1164/rccm.200812-1827oc] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
RATIONALE Transcriptional coactivator with PDZ-binding motif (TAZ) is assumed to act as a coactivator of several transcription factors including smad2/3. In the lung, surfactant protein C (Sftpc) is known to be a downstream target of thyroid transcription factor-1 (TTF-1)-TAZ transcriptional coactivation. OBJECTIVES The lung phenotype of Taz-deficient mice was explored. METHODS Taz-deficient mice were analyzed pathologically and physiologically. Next, we performed microarray analysis to determine the genes closely related to abnormal lung development. Finally, Taz-heterozygous mice were injected with bleomycin. MEASUREMENTS AND MAIN RESULTS Taz-deficient homozygotes showed abnormal alveolarization during lung development, which caused in adult mice airspace enlargement mimicking emphysema. There was no significant difference in the expression of Sftpc between wild-type and Taz-deficient lungs. Instead, microarray analysis identified some candidate downstream genes related to the pathogenesis, including the connective tissue growth factor (Ctgf) gene, which is required for normal lung development. In vitro studies showed that TAZ up-regulated Ctgf expression not only by reinforcing transforming growth factor-beta/smad signals, but also by interfering in the more proximal Ctgf promoter region (from bp -123 to -76), defined as the TAZ response element. Furthermore, Taz-heterozygous mice were resistant to bleomycin-induced lung fibrosis. CONCLUSIONS The results indicate the importance of TAZ in lung alveolarization and its involvement in the pathogenesis of lung fibrosis.
Collapse
Affiliation(s)
- Akihisa Mitani
- Department of Respiratory Medicine, Graduate School of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | | | | | |
Collapse
|
109
|
Bourbon JR, Boucherat O, Boczkowski J, Crestani B, Delacourt C. Bronchopulmonary dysplasia and emphysema: in search of common therapeutic targets. Trends Mol Med 2009; 15:169-79. [DOI: 10.1016/j.molmed.2009.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/11/2009] [Accepted: 02/11/2009] [Indexed: 11/15/2022]
|
110
|
Cao L, Wang J, Tseu I, Luo D, Post M. Maternal exposure to endotoxin delays alveolarization during postnatal rat lung development. Am J Physiol Lung Cell Mol Physiol 2009; 296:L726-37. [PMID: 19218354 DOI: 10.1152/ajplung.90405.2008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Maternal bacterial infections adversely affect lung development by crossing the placental barrier and infecting the developing fetus. The underlying mechanism negatively affecting pulmonary development remains unknown. Herein, we investigated whether a systemic maternal infection affects postnatal inflammation and alveolar development. Pregnant rats were injected with 2.5 mg/kg LPS on day 20 and 21 (term = 22 days). Postnatal (PN0-21) mRNA and protein expression of cytokines (IL-1beta, IL-6, IL-10, CXCL1/2, TNFalpha) and genes implicated in alveologenesis [tropoelastin, lysyl oxidase (LOX), lysyl oxidase-like (LOXL)1, tenascin-C (TNC), fibulin 5, vascular endothelial growth factor (VEGF-A), VEGF receptor (VEGFR)2, VEGFR1, platelet-derived growth factor (PDGF)A, PDGFB, and PDGFRalpha] were quantified by real-time PCR and beadlyte technology. Lung transcript and protein levels of IL-1beta, IL-6, and CXCL1/2 were significantly greater in LPS-exposed pups than those of control pups at PN0, 2, 6, 10, and 14. Bronchoalveolar lavage fluid (BALF) of LPS-exposed animals contained significantly more macrophages at PN2 and 14 than BALF of control pups. Morphometric analysis revealed that LPS-exposed animals had fewer and larger alveoli, fewer secondary septa, and decreased peripheral vessel density when compared with control pups. This morphological delay in alveolar development disappeared after PN14. Tropoelastin, LOXL1, VEGF, VEGFR2, and PDGFRalpha mRNA expression of LPS-exposed animals was significantly greater than those of control animals in PN2-14 lungs. TNC, LOX, fibulin 5, VEGFR1, PDGFA, and PDGFB expression was not affected by maternal LPS exposure. Together, the data demonstrate that maternal exposure to endotoxin results in a prolonged pulmonary inflammation postnatally, altered gene expression of molecules implicated in alveologenesis, and delayed morphological maturation of the lung.
Collapse
Affiliation(s)
- Lei Cao
- The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | | | | | | | | |
Collapse
|
111
|
MOON C, JEONG J, SHIN MK, MIN DS, SHIN T. Expression of Phospholipase D Isozymes in Mouse Lungs during Postnatal Development. J Vet Med Sci 2009; 71:965-8. [DOI: 10.1292/jvms.71.965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Changjong MOON
- Department of Veterinary Anatomy, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University
| | - Jinwoo JEONG
- Department of Veterinary Anatomy, College of Veterinary Medicine and Applied Radiological Science Research Institute, Jeju National University
| | - Min Kyoung SHIN
- Department of Molecular Biology, College of Natural Science, Pusan National University
| | - Do Sik MIN
- Department of Molecular Biology, College of Natural Science, Pusan National University
| | - Taekyun SHIN
- Department of Veterinary Anatomy, College of Veterinary Medicine and Applied Radiological Science Research Institute, Jeju National University
| |
Collapse
|
112
|
Tsuda A, Filipovic N, Haberthür D, Dickie R, Matsui Y, Stampanoni M, Schittny JC. Finite element 3D reconstruction of the pulmonary acinus imaged by synchrotron X-ray tomography. J Appl Physiol (1985) 2008; 105:964-76. [PMID: 18583378 PMCID: PMC2536812 DOI: 10.1152/japplphysiol.90546.2008] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Accepted: 06/16/2008] [Indexed: 11/22/2022] Open
Abstract
The alveolated structure of the pulmonary acinus plays a vital role in gas exchange function. Three-dimensional (3D) analysis of the parenchymal region is fundamental to understanding this structure-function relationship, but only a limited number of attempts have been conducted in the past because of technical limitations. In this study, we developed a new image processing methodology based on finite element (FE) analysis for accurate 3D structural reconstruction of the gas exchange regions of the lung. Stereologically well characterized rat lung samples (Pediatr Res 53: 72-80, 2003) were imaged using high-resolution synchrotron radiation-based X-ray tomographic microscopy. A stack of 1,024 images (each slice: 1024 x 1024 pixels) with resolution of 1.4 mum(3) per voxel were generated. For the development of FE algorithm, regions of interest (ROI), containing approximately 7.5 million voxels, were further extracted as a working subunit. 3D FEs were created overlaying the voxel map using a grid-based hexahedral algorithm. A proper threshold value for appropriate segmentation was iteratively determined to match the calculated volume density of tissue to the stereologically determined value (Pediatr Res 53: 72-80, 2003). The resulting 3D FEs are ready to be used for 3D structural analysis as well as for subsequent FE computational analyses like fluid dynamics and skeletonization.
Collapse
Affiliation(s)
- A Tsuda
- Molecular and Integrative Physiological Sciences, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA.
| | | | | | | | | | | | | |
Collapse
|