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Han P, Jiao A, Yin J, Zou H, Liu Y, Li Z, Wang Q, Wu J, Shen K. Analysis of risk factors for acute attacks complicated by respiratory failure in children with asthma. Front Pediatr 2024; 11:1335540. [PMID: 38288264 PMCID: PMC10823024 DOI: 10.3389/fped.2023.1335540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/31/2023] [Indexed: 01/31/2024] Open
Abstract
Objective To describe the proportion and clinical characteristics of hospitalized children with acute asthma attacks complicated by respiratory failure and to analyze the risk factors. Methods This retrospective study analyzed hospital admissions of children and adolescents with acute asthma attacks between January 2016 and December 2021. Inclusion criteria were used to identify eligible cases, and demographic information and disease characteristics were collected. Patients were categorized into respiratory failure group and the other group based on the result of artery blood gas analysis. Multivariate logistic regression was utilized to investigate the risk factors associated with respiratory failure resulting from acute asthma attacks. The data were analyzed using SPSS 22.0, and significance was considered at P < 0.05. Results Our research involved 225 participants, with 18.7% diagnosed with respiratory failure. The respiratory failure group was found to be younger and have higher percentage of male, while birth weight, nationality, and type of residence did not differ between the two groups. In the respiratory failure group, a significant difference was observed in emergency hospitalization, ICU treatment, severe to critical attack, dyspnea and allergy history. The two groups did not differ in admission season, first asthma diagnosis, respiratory infection and comorbidity. The respiratory failure group exhibited a higher proportion of atopy-only asthma and a lower proportion of T2-high asthma. The eosinophil count, and eosinophil percentage were lower in the respiratory failure group, while neutrophil count was higher. Having a history of allergies (OR = 2.46, 95% CI: 1.08-5.59) and neutrophil count (OR = 1.10, 95% CI: 1.00-1.21) were the risk factors for respiratory failure in children with asthma. There also existed that the risk of respiratory failure increases with decreasing age of the children (OR = 0.85, 95% CI: 0.73-0.99). Conclusion Notably, risk factors for respiratory failure in hospitalized asthma children include age, having a history of allergies, and neutrophil count. The identification of the above factors and the implementation of timely intervention can optimize the treatment of asthma in children.
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Affiliation(s)
- Peng Han
- Respiratory Department, China National Clinical Research Center of Respiratory Diseases, Beijing, China, Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Anxia Jiao
- Department of Interventional Pulmonology, Beijing Children’s Hospital, National Center for Children’s Health, Capital Medical University, Beijing, China
| | - Ju Yin
- Respiratory Department, China National Clinical Research Center of Respiratory Diseases, Beijing, China, Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Huimin Zou
- Respiratory Department, China National Clinical Research Center of Respiratory Diseases, Beijing, China, Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Yuliang Liu
- Respiratory Department, China National Clinical Research Center of Respiratory Diseases, Beijing, China, Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Zheng Li
- Pediatric Intensive Care Unit, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Quan Wang
- Pediatric Intensive Care Unit, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Jie Wu
- Department of Emergency, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Kunling Shen
- Respiratory Department, China National Clinical Research Center of Respiratory Diseases, Beijing, China, Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
- Department of Pediatrics, Shenzhen Children’s Hospital, Shenzhen, China
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2
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Essey M, Maina JN. Fractal analysis of concurrently prepared latex rubber casts of the bronchial and vascular systems of the human lung. Open Biol 2020; 10:190249. [PMID: 32634372 PMCID: PMC7574555 DOI: 10.1098/rsob.190249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 06/12/2020] [Indexed: 12/17/2022] Open
Abstract
Fractal geometry (FG) is a branch of mathematics that instructively characterizes structural complexity. Branched structures are ubiquitous in both the physical and the biological realms. Fractility has therefore been termed nature's design. The fractal properties of the bronchial (airway) system, the pulmonary artery and the pulmonary vein of the human lung generates large respiratory surface area that is crammed in the lung. Also, it permits the inhaled air to intimately approximate the pulmonary capillary blood across a very thin blood-gas barrier through which gas exchange to occur by diffusion. Here, the bronchial (airway) and vascular systems were simultaneously cast with latex rubber. After corrosion, the bronchial and vascular system casts were physically separated and cleared to expose the branches. The morphogenetic (Weibel's) ordering method was used to categorize the branches on which the diameters and the lengths, as well as the angles of bifurcation, were measured. The fractal dimensions (DF) were determined by plotting the total branch measurements against the mean branch diameters on double logarithmic coordinates (axes). The diameter-determined DF values were 2.714 for the bronchial system, 2.882 for the pulmonary artery and 2.334 for the pulmonary vein while the respective values from lengths were 3.098, 3.916 and 4.041. The diameters yielded DF values that were consistent with the properties of fractal structures (i.e. self-similarity and space-filling). The data obtained here compellingly suggest that the design of the bronchial system, the pulmonary artery and the pulmonary vein of the human lung functionally comply with the Hess-Murray law or 'the principle of minimum work'.
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Affiliation(s)
| | - John N. Maina
- Department of Zoology, University of Johannesburg,
Auckland Park Campus, Kingsway, Johannesburg 2006, South
Africa
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3
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Ahookhosh K, Pourmehran O, Aminfar H, Mohammadpourfard M, Sarafraz MM, Hamishehkar H. Development of human respiratory airway models: A review. Eur J Pharm Sci 2020; 145:105233. [DOI: 10.1016/j.ejps.2020.105233] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/11/2020] [Accepted: 01/20/2020] [Indexed: 10/25/2022]
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Dunican EM, Watchorn DC, Fahy JV. Autopsy and Imaging Studies of Mucus in Asthma. Lessons Learned about Disease Mechanisms and the Role of Mucus in Airflow Obstruction. Ann Am Thorac Soc 2018; 15:S184-S191. [PMID: 30431352 PMCID: PMC6322032 DOI: 10.1513/annalsats.201807-485aw] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 09/20/2018] [Indexed: 12/11/2022] Open
Abstract
Autopsy studies in fatal asthma have clearly documented the central role of airway plugging with pathologic mucus in the pathophysiology of death from asthma, but the role of mucus plugs in chronic severe asthma has been less well understood. Recently, multidetector computerized tomography imaging of the lungs has emerged as a valuable method to visualize mucus plugs in asthma. These multidetector computerized tomography data have revealed mucus plugs as a common occurrence in severe forms of asthma. In addition, an image-based mucus plug scoring system shows that mucus plugs are strongly associated with measures of airflow obstruction and with biomarkers of type 2 cytokine and eosinophilic inflammation. These data provide a rationale for treating airflow obstruction in severe asthma with mucolytics, and they also raise the possibility that treatments that target type 2 inflammation may decrease mucus plugs in asthma.
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Affiliation(s)
- Eleanor M Dunican
- 1 Department of Medicine, University College Dublin, Dublin, Ireland; and
| | - David C Watchorn
- 1 Department of Medicine, University College Dublin, Dublin, Ireland; and
| | - John V Fahy
- 2 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
- 3 Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
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5
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Dunican EM. Seeing the forest for the trees: fractal dimensions measure COPD airway remodeling. J Clin Invest 2018; 128:5203-5205. [PMID: 30371506 DOI: 10.1172/jci124776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is extremely heterogenous in its effects on airway remodeling. Parsing the complex and interrelated morphologic changes and understanding their contribution to disease severity has posed a significant challenge to the field. In the current issue of the JCI, Bodduluri et al. measured the complex effects of COPD on the airway tree using airway fractal dimension (AFD) on computerized tomography in a large cohort of smokers with and without COPD. They found that lower AFD was independently associated with disease severity and mortality in COPD. This work highlights AFD as a noninvasive approach to analyze complex changes in airway geometry.
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6
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Boser SR, Mauad T, de Araújo-Paulino BB, Mitchell I, Shrestha G, Chiu A, Butt J, Kelly MM, Caldini E, James A, Green FHY. Myofibroblasts are increased in the lung parenchyma in asthma. PLoS One 2017; 12:e0182378. [PMID: 28787016 PMCID: PMC5546673 DOI: 10.1371/journal.pone.0182378] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022] Open
Abstract
Background Increased airway smooth muscle is observed in large and small airways in asthma. Semi-quantitative estimates suggest that cells containing alpha smooth muscle actin (α-SMA) are also increased in the lung parenchyma. This study quantified and characterized α-SMA positive cells (α-SMA+) in the lung parenchyma of non-asthmatic and asthmatic individuals. Methods Post-mortem sections of peripheral lung from cases of fatal asthma (FA), persons with asthma dying of non-respiratory causes (NFA) and non-asthma control subjects (NAC) were stained for α-SMA, quantified using point-counting and normalised to alveolar basement membrane length and interstitial area. Results α-SMA+ fractional area was increased in alveolar parenchyma in both FA (14.7 ± 2.8% of tissue area) and NFA (13.0 ± 1.2%), compared with NAC (7.4 ± 2.4%), p < 0.05 The difference was greater in upper lobes compared with lower lobes (p < 0.01) in both asthma groups. Similar changes were observed in alveolar ducts and alveolar walls. The electron microscopic features of the α-SMA+ cells were characteristic of myofibroblasts. Conclusions We conclude that in asthma there is a marked increase in α-SMA+ myofibroblasts in the lung parenchyma. The physiologic consequences of this increase are unknown.
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Affiliation(s)
- Stacey R. Boser
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Thais Mauad
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | | | - Ian Mitchell
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Grishma Shrestha
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrea Chiu
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - John Butt
- Pathfinder Forum, Forensic Pathology, Vancouver, British Columbia, Canada
| | - Margaret M. Kelly
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Elia Caldini
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Alan James
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Francis H. Y. Green
- Airway Inflammation Group, Snyder Institute of Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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7
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Haenssgen K, Makanya AN, Djonov V. Casting materials and their application in research and teaching. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:493-513. [PMID: 24564951 DOI: 10.1017/s1431927613014050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
From a biological point of view, casting refers to filling of anatomical and/or pathological spaces with extraneous material that reproduces a three-dimensional replica of the space. Casting may be accompanied by additional procedures such as corrosion, in which the soft tissue is digested out, leaving a clean cast, or the material may be mixed with radiopaque substances to allow x-ray photography or micro computed topography (µCT) scanning. Alternatively, clearing of the surrounding soft tissue increases transparency and allows visualization of the casted cavities. Combination of casting with tissue fixation allows anatomical dissection and didactic surgical procedures on the tissue. Casting materials fall into three categories namely, aqueous substances (India ink, Prussian blue ink), pliable materials (gelatins, latex, and silicone rubber), or hard materials (methyl methacrylates, polyurethanes, polyesters, and epoxy resins). Casting has proved invaluable in both teaching and research and many phenomenal biological processes have been discovered through casting. The choice of a particular material depends inter alia on the targeted use and the intended subsequent investigative procedures, such as dissection, microscopy, or µCT. The casting material needs to be pliable where anatomical and surgical manipulations are intended, and capillary-passable for ultrastructural investigations.
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Affiliation(s)
- Kati Haenssgen
- 1 Institute of Anatomy, University of Bern, Baltzerstrasse 2, Ch-3000 Bern 9, Switzerland
| | - Andrew N Makanya
- 1 Institute of Anatomy, University of Bern, Baltzerstrasse 2, Ch-3000 Bern 9, Switzerland
| | - Valentin Djonov
- 1 Institute of Anatomy, University of Bern, Baltzerstrasse 2, Ch-3000 Bern 9, Switzerland
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8
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Laakkonen J, Kivalo M. The Use of Silicone Casts in Collection of Morphological Data from Free-Ranging Wildlife — the Case of Tracheobronchial Anatomy of the Eurasian Lynx (Lynx lynx). ANN ZOOL FENN 2013. [DOI: 10.5735/085.050.0501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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9
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Jacob RE, Colby SM, Kabilan S, Einstein DR, Carson JP. In situ casting and imaging of the rat airway tree for accurate 3D reconstruction. Exp Lung Res 2013; 39:249-57. [PMID: 23786464 DOI: 10.3109/01902148.2013.801535] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The use of anatomically accurate, animal-specific airway geometries is important for understanding and modeling the physiology of the respiratory system. One approach for acquiring detailed airway architecture is to create a bronchial cast of the conducting airways. However, typical casting procedures either do not faithfully preserve the in vivo branching angles or produce rigid casts that when removed for imaging are fragile and thus easily damaged. We address these problems by creating an in situ bronchial cast of the conducting airways in rats that can be subsequently imaged in situ using three-dimensional micro-CT imaging. We also demonstrate that deformations in airway branch angles resulting from the casting procedure are small, and that these angle deformations can be reversed through an interactive adjustment of the segmented cast geometry. Animal work was approved by the Institutional Animal Care and Use Committee of Pacific Northwest National Laboratory.
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Affiliation(s)
- Richard E Jacob
- Department of Systems Toxicology, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
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10
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Asgharian B, Price O, McClellan G, Corley R, Einstein DR, Jacob RE, Harkema J, Carey SA, Schelegle E, Hyde D, Kimbell JS, Miller FJ. Development of a rhesus monkey lung geometry model and application to particle deposition in comparison to humans. Inhal Toxicol 2012; 24:869-99. [PMID: 23121298 PMCID: PMC5119470 DOI: 10.3109/08958378.2012.725782] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 µm in size were examined for endotracheal and and up to 5 µm for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model.
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Affiliation(s)
- Bahman Asgharian
- Applied Research Associates, Inc., 8537 Six Forks Road, Suite 600, Raleigh, NC 27615-2963, USA.
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11
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Neradilek MB, Polissar NL, Einstein DR, Glenny RW, Minard KR, Carson JP, Jiao X, Jacob RE, Cox TC, Postlethwait EM, Corley RA. Branch-based model for the diameters of the pulmonary airways: accounting for departures from self-consistency and registration errors. Anat Rec (Hoboken) 2012; 295:1027-44. [PMID: 22528468 PMCID: PMC5581196 DOI: 10.1002/ar.22476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/06/2012] [Indexed: 11/08/2022]
Abstract
We examine a previously published branch-based approach for modeling airway diameters that is predicated on the assumption of self-consistency across all levels of the tree. We mathematically formulate this assumption, propose a method to test it and develop a more general model to be used when the assumption is violated. We discuss the effect of measurement error on the estimated models and propose methods that take account of error. The methods are illustrated on data from MRI and CT images of silicone casts of two rats, two normal monkeys, and one ozone-exposed monkey. Our results showed substantial departures from self-consistency in all five subjects. When departures from self-consistency exist, we do not recommend using the self-consistency model, even as an approximation, as we have shown that it may likely lead to an incorrect representation of the diameter geometry. The new variance model can be used instead. Measurement error has an important impact on the estimated morphometry models and needs to be addressed in the analysis.
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Affiliation(s)
- Moni B Neradilek
- The-Mountain-Whisper-Light Statistics, Seattle, Washington, USA.
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12
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Corley RA, Kabilan S, Kuprat AP, Carson JP, Minard KR, Jacob RE, Timchalk C, Glenny R, Pipavath S, Cox T, Wallis CD, Larson RF, Fanucchi MV, Postlethwait EM, Einstein DR. Comparative computational modeling of airflows and vapor dosimetry in the respiratory tracts of rat, monkey, and human. Toxicol Sci 2012; 128:500-16. [PMID: 22584687 DOI: 10.1093/toxsci/kfs168] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Computational fluid dynamics (CFD) models are useful for predicting site-specific dosimetry of airborne materials in the respiratory tract and elucidating the importance of species differences in anatomy, physiology, and breathing patterns. We improved the imaging and model development methods to the point where CFD models for the rat, monkey, and human now encompass airways from the nose or mouth to the lung. A total of 1272, 2172, and 135 pulmonary airways representing 17±7, 19±9, or 9±2 airway generations were included in the rat, monkey and human models, respectively. A CFD/physiologically based pharmacokinetic model previously developed for acrolein was adapted for these anatomically correct extended airway models. Model parameters were obtained from the literature or measured directly. Airflow and acrolein uptake patterns were determined under steady-state inhalation conditions to provide direct comparisons with prior data and nasal-only simulations. Results confirmed that regional uptake was sensitive to airway geometry, airflow rates, acrolein concentrations, air:tissue partition coefficients, tissue thickness, and the maximum rate of metabolism. Nasal extraction efficiencies were predicted to be greatest in the rat, followed by the monkey, and then the human. For both nasal and oral breathing modes in humans, higher uptake rates were predicted for lower tracheobronchial tissues than either the rat or monkey. These extended airway models provide a unique foundation for comparing material transport and site-specific tissue uptake across a significantly greater range of conducting airways in the rat, monkey, and human than prior CFD models.
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Affiliation(s)
- Richard A Corley
- Systems Toxicology, Pacific Northwest National Laboratory Richland, Washington 99352, USA.
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13
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Lee D, Wallis C, Van Winkle LS, Wexler AS. Disruption of tracheobronchial airway growth following postnatal exposure to ozone and ultrafine particles. Inhal Toxicol 2011; 23:520-31. [PMID: 21780864 DOI: 10.3109/08958378.2011.591447] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study examined airway structure changes in adult rats after a long recovery period due to sub-chronic juvenile exposure to ozone and ultrafine particles that have a high organic fraction. Neonatal male Sprague-Dawley rats were exposed during lung development to 3 cycles of 0.5 ppm ozone from postnatal day 7 through 25. Two different exposure patterns were used: 5-day exposure per week (Ozone52) or 2-day exposure per week (Ozone25) with or without co-exposure to ultrafine particles (OPFP5252, OPFP5225). Airway architecture was evaluated at 81 days of age, after 56 days of continued development beyond the exposure period in filtered air (FA). By analyzing CT images from lung airway casts, we determined airway diameter, length, branching angle, and rotation angle for most conducting airways. Compared with the FA control group, the Ozone52 group showed significant decreases in airway diameter in generations larger than 10 especially in the right diaphragmatic lobe and in airway length in distal generations, while changes in airway structure due to the Ozone25 exposure were not appreciable. Interaction effects of ozone and ultrafine particle exposures were not significant. These results suggest that airway alterations due to postnatal ozone exposure are not limited to the distal region but occur extensively from the middle to distal conducting airways. Further, alterations due to early ozone exposure do not recover nearly 2 months after exposure has ceased demonstrating a persistent airway structural change following an early life exposure to ozone.
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Affiliation(s)
- Dongyoub Lee
- Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA
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14
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Carson JP, Einstein DR, Minard KR, Fanucchi MV, Wallis CD, Corley RA. High resolution lung airway cast segmentation with proper topology suitable for computational fluid dynamic simulations. Comput Med Imaging Graph 2010; 34:572-8. [PMID: 20382502 DOI: 10.1016/j.compmedimag.2010.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 12/01/2009] [Accepted: 03/10/2010] [Indexed: 10/19/2022]
Abstract
Developing detailed lung airway models is an important step towards understanding the respiratory system. While modern imaging and airway casting approaches have dramatically improved the potential detail of such models, challenges have arisen in image processing as the demand for greater detail pushes the image processing approaches to their limits. Airway segmentations with proper topology have neither loops nor invalid voxel-to-voxel connections. Here we describe a new technique for segmenting airways with proper topology and apply the approach to an image volume generated by magnetic resonance imaging of a silicone cast created from an excised monkey lung.
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Affiliation(s)
- James P Carson
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, USA.
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15
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Wempe F, De-Zolt S, Koli K, Bangsow T, Parajuli N, Dumitrascu R, Sterner-Kock A, Weissmann N, Keski-Oja J, von Melchner H. Inactivation of sestrin 2 induces TGF-beta signaling and partially rescues pulmonary emphysema in a mouse model of COPD. Dis Model Mech 2010; 3:246-53. [PMID: 20106877 DOI: 10.1242/dmm.004234] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Cigarette smoking has been identified as one of the major risk factors and several predisposing genetic factors have been implicated in the pathogenesis of COPD, including a single nucleotide polymorphism (SNP) in the latent transforming growth factor (TGF)-beta binding protein 4 (Ltbp4)-encoding gene. Consistent with this finding, mice with a null mutation of the short splice variant of Ltbp4 (Ltbp4S) develop pulmonary emphysema that is reminiscent of COPD. Here, we report that the mutational inactivation of the antioxidant protein sestrin 2 (sesn2) partially rescues the emphysema phenotype of Ltbp4S mice and is associated with activation of the TGF-beta and mammalian target of rapamycin (mTOR) signal transduction pathways. The results suggest that sesn2 could be clinically relevant to patients with COPD who might benefit from antagonists of sestrin function.
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Affiliation(s)
- Frank Wempe
- Department of Molecular Hematology, University of Frankfurt Medical School, 60590 Frankfurt am Main, Germany
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16
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Einstein DR, Neradilak B, Pollisar N, Minard KR, Wallis C, Fanucchi M, Carson JP, Kuprat AP, Kabilan S, Jacob RE, Corley RA. An automated self-similarity analysis of the pulmonary tree of the Sprague-Dawley rat. Anat Rec (Hoboken) 2009; 291:1628-48. [PMID: 18951511 DOI: 10.1002/ar.20771] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We present the results of an automated analysis of the morphometry of the pulmonary airway trees of the Sprague-Dawley rat. Our work is motivated by a need to inform lower-dimensional mathematical models to prescribe realistic boundary conditions for multiscale hybrid models of rat lung mechanics. Silicone casts were made from three age-matched, male Sprague-Dawley rats, immersed in a gel containing a contrast agent and subsequently imaged with magnetic resonance (MR). From a segmentation of this data, we extracted a connected graph, representing the airway centerline. Segment statistics (lengths and diameters) were derived from this graph. To validate this MR imaging/digital analysis method, airway segment measurements were compared with nearly 1,000 measurements collected by hand using an optical microscope from one of the rat lung casts. To evaluate the reproducibility of the MR imaging/digital analysis method, two lung casts were each imaged three times with randomized orientations in the MR bore. Diameters and lengths of randomly selected airways were compared among each of the repeated imaging datasets to estimate the variability. Finally, we analyzed the morphometry of the airway tree by assembling individual airway segments into structures that span multiple generations, which we call branches. We show that branches not segments are the fundamental repeating unit in the rat lung and develop simple mathematical relationships describing these structures for the entire lung. Our analysis shows that airway diameters and lengths have both a deterministic and stochastic character.
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Affiliation(s)
- Daniel R Einstein
- Biological Monitoring and Modeling, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
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Minard KR, Einstein DR, Jacob RE, Kabilan S, Kuprat AP, Timchalk CA, Trease LL, Corley RA. Application of Magnetic Resonance (MR) Imaging for the Development and Validation of Computational Fluid Dynamic (CFD) Models of the Rat Respiratory System. Inhal Toxicol 2008; 18:787-94. [PMID: 16774868 DOI: 10.1080/08958370600748729] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Computational fluid dynamic (CFD) models of the respiratory system provide a quantitative basis for extrapolating the localized dose of inhaled materials and improving human health risk assessments based upon inhalation studies conducted in animals. Nevertheless, model development and validation have historically been tedious and time-consuming tasks. In recognition of this, we previously reported on the use of proton (1H) magnetic resonance (MR) imaging for visualizing nasal-sinus passages in the rat, and for speeding computational mesh generation. Here, the generation and refinement of meshes for rat nasal airways are described in more detail and simulated airflows are presented. To extend the CFD models to the complete respiratory tract, three-dimensional (3D) 1H MR imaging of rat pulmonary casts was also utilized to construct pulmonary airway meshes using procedures developed for the nasal airways. Furthermore, the feasibility of validating CFD predictions with MR was tested by imaging hyperpolarized 3He gas at physiological flow rates in a straight pipe with a diameter comparable to the rat trachea. Results from these diverse studies highlight the potential utility of MR imaging not only for speeding CFD development but also possibly for model validation.
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Affiliation(s)
- Kevin R Minard
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
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Lee D, Fanucchi MV, Plopper CG, Fung J, Wexler AS. Pulmonary Architecture in the Conducting Regions of Six Rats. Anat Rec (Hoboken) 2008; 291:916-26. [DOI: 10.1002/ar.20726] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Boser SR, Park H, Perry SF, Ménache MG, Green FHY. Fractal geometry of airway remodeling in human asthma. Am J Respir Crit Care Med 2005; 172:817-23. [PMID: 15976372 DOI: 10.1164/rccm.200411-1463oc] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Airway wall remodeling is an important aspect of asthma. It has proven difficult to assess quantitatively as it involves changes in several components of the airway wall. OBJECTIVE To develop a simple method for quantifying the overall severity of airway wall remodeling in asthmatic airways using fractal geometry. METHODS Negative-pressure silicone rubber casts of lungs were made using autopsy material from three groups: fatal asthma, nonfatal asthma, and nonasthma control. All subjects were lifelong nonsmokers. A fractal dimension was calculated on two-dimensional digital images of each cast. RESULTS Nonasthma control casts had smooth walls and dichotomous branching patterns with nontapering segments. Asthmatic casts showed many abnormalities, including airway truncation from mucous plugs, longitudinal ridges, and horizontal corrugations corresponding to elastic bundles and smooth muscle hypertrophy, respectively, and surface projections associated with ectatic mucous gland ducts. Fractal dimensions were calculated from digitized images using an information method. The average fractal dimensions of the airways of both the fatal asthma (1.72) and nonfatal asthma (1.76) groups were significantly (p<0.01 and p=0.032, respectively) lower than that of the nonasthma control group (1.83). The lower fractal dimension of asthmatic airways correlated with a decreased overall structural complexity and pathologic severity of disease. CONCLUSION Fractal analysis is a simple and useful technique for quantifying the chronic structural changes of airway remodeling in asthma.
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