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Fajardo-Campoverdi A, Ibarra-Estrada M, González-Castro A, Cortés A, Núñez-Silveira J. High rate-trauma: the new world order? Med Intensiva 2024; 48:490-492. [PMID: 38594111 DOI: 10.1016/j.medine.2024.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Affiliation(s)
- Aurio Fajardo-Campoverdi
- Universidad de la Frontera, Critical Care Unit, Hospital Biprovincial Quillota-Petorca, Quillota, Chile.
| | - Miguel Ibarra-Estrada
- Medicine of the Critically Ill, Civil Hospital Fray Antonio Alcalde and Instituto Jalisciense de Cancerología, Guadalajara, Mexico
| | | | - Alejandra Cortés
- Critical Care Unit, Hospital Biprovincial Quillota-Petorca, Quillota, Chile
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2
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Laville C, Fetita C, Gille T, Brillet PY, Nunes H, Bernaudin JF, Genet M. Comparison of optimization parametrizations for regional lung compliance estimation using personalized pulmonary poromechanical modeling. Biomech Model Mechanobiol 2023; 22:1541-1554. [PMID: 36913005 PMCID: PMC10009868 DOI: 10.1007/s10237-023-01691-9] [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: 09/30/2022] [Accepted: 01/09/2023] [Indexed: 03/14/2023]
Abstract
Interstitial lung diseases, such as idiopathic pulmonary fibrosis (IPF) or post-COVID-19 pulmonary fibrosis, are progressive and severe diseases characterized by an irreversible scarring of interstitial tissues that affects lung function. Despite many efforts, these diseases remain poorly understood and poorly treated. In this paper, we propose an automated method for the estimation of personalized regional lung compliances based on a poromechanical model of the lung. The model is personalized by integrating routine clinical imaging data - namely computed tomography images taken at two breathing levels in order to reproduce the breathing kinematic-notably through an inverse problem with fully personalized boundary conditions that is solved to estimate patient-specific regional lung compliances. A new parametrization of the inverse problem is introduced in this paper, based on the combined estimation of a personalized breathing pressure in addition to material parameters, improving the robustness and consistency of estimation results. The method is applied to three IPF patients and one post-COVID-19 patient. This personalized model could help better understand the role of mechanics in pulmonary remodeling due to fibrosis; moreover, patient-specific regional lung compliances could be used as an objective and quantitative biomarker for improved diagnosis and treatment follow up for various interstitial lung diseases.
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Affiliation(s)
- Colin Laville
- Laboratoire de Mécanique des Solides, École Polytechnique/CNRS/IPP, Palaiseau, France
- Inria, Palaiseau, France
| | | | - Thomas Gille
- Hypoxie et Poumon, Université Sorbonne Paris Nord/INSERM, Bobigny, France
- Hôpital Avicenne, APHP, Bobigny, France
| | - Pierre-Yves Brillet
- Hypoxie et Poumon, Université Sorbonne Paris Nord/INSERM, Bobigny, France
- Hôpital Avicenne, APHP, Bobigny, France
| | - Hilario Nunes
- Hypoxie et Poumon, Université Sorbonne Paris Nord/INSERM, Bobigny, France
- Hôpital Avicenne, APHP, Bobigny, France
| | | | - Martin Genet
- Laboratoire de Mécanique des Solides, École Polytechnique/CNRS/IPP, Palaiseau, France
- Inria, Palaiseau, France
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3
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Roberts JD. LungElast-an open-source, flexible, low-cost, microprocessor-controlled mouse lung elastometer. Sci Rep 2023; 13:11246. [PMID: 37438462 PMCID: PMC10338507 DOI: 10.1038/s41598-023-38310-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/06/2023] [Indexed: 07/14/2023] Open
Abstract
The study of mouse lung mechanics provides essential insights into the physiological mechanisms of pulmonary disease. Consequently, investigators assemble custom systems comprising infusion-withdrawal syringe pumps and analog pressure sensors to investigate the lung function of these animals. But these systems are expensive and require ongoing regulation, making them challenging to use. Here I introduce LungElast, an open-source, inexpensive, and self-contained instrument that can experimentally determine lung elasticity and volumes even in immature mice. It is assembled using custom 3D printed parts and readily available or easily constructed components. In this device, a microprocessor-controlled stepper motor automatically regulates lung volume by precisely driving a syringe piston whose position is determined using time-of-flight LIDAR technology. The airway pressures associated with the lung volumes are determined using compact sensor-on-chip technology, retrieved in a digital format, and stored by the microcontroller. The instrument software is modular, which eases device testing, calibration, and use. Data are also provided here that specify the accuracy and precision of the elastometer's sensors and volume delivery and demonstrate its use with lung models and mouse pups. This instrument has excellent potential for research and educational work.
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Affiliation(s)
- Jesse D Roberts
- Cardiovascular Research Center of the General Medical Services and the Departments of Anesthesia, Critical Care and Pain Medicine, Pediatrics, and Medicine, Massachusetts General Hospital - East, 149 13th St, Boston, MA, USA.
- Harvard Medical School, Harvard University, Cambridge, MA, USA.
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4
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Daphalapurkar N, Riglin J, Mohan A, Harris J, Bernardin J. Quasi-dynamic breathing model of the lung incorporating viscoelasticity of the lung tissue. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023:e3744. [PMID: 37334440 DOI: 10.1002/cnm.3744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 03/21/2023] [Accepted: 06/05/2023] [Indexed: 06/20/2023]
Abstract
We advanced a novel model to calculate viscoelastic lung compliance and airflow resistance in presence of mucus, accounting for the quasi-linear viscoelastic stress-strain response of the parenchyma (alveoli) tissue. We adapted a continuum-based numerical modeling approach for the lung, integrating the fluid mechanics of the airflow within individual generations of the bronchi and alveoli. The model accounts for elasticity of the deformable bronchioles, resistance to airflow due to the presence of mucus within the bronchioles, and subsequent mucus flow. Simulated quasi-dynamic inhalation and expiration cycles were used to characterize the net compliance and resistance of the lung, considering the rheology of the mucus and viscoelastic properties of the parenchyma tissue. The structure and material properties of the lung were identified to have an important contribution to the lung compliance and airflow resistance. The secondary objective of this work was to assess whether a higher frequency and smaller volume of harmonic air flow rate compared to a normal ventilator breathing cycle enhanced mucus outflow. Results predict, lower mucus viscosity and higher excitation frequency of breathing are favorable for the flow of mucus up the bronchi tree, towards the trachea.
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Affiliation(s)
- Nitin Daphalapurkar
- Fluid Dynamics and Solid Mechanics, T-3, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Jacob Riglin
- Mechanical and Thermal Engineering, E-1, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Arvind Mohan
- Computational Physics and Methods, CCS-2, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Jennifer Harris
- Biosecurity and Public Health, B-10, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - John Bernardin
- Mechanical and Thermal Engineering, E-1, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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5
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Knudsen L, Hummel B, Wrede C, Zimmermann R, Perlman CE, Smith BJ. Acinar micromechanics in health and lung injury: what we have learned from quantitative morphology. Front Physiol 2023; 14:1142221. [PMID: 37025383 PMCID: PMC10070844 DOI: 10.3389/fphys.2023.1142221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/09/2023] [Indexed: 04/08/2023] Open
Abstract
Within the pulmonary acini ventilation and blood perfusion are brought together on a huge surface area separated by a very thin blood-gas barrier of tissue components to allow efficient gas exchange. During ventilation pulmonary acini are cyclically subjected to deformations which become manifest in changes of the dimensions of both alveolar and ductal airspaces as well as the interalveolar septa, composed of a dense capillary network and the delicate tissue layer forming the blood-gas barrier. These ventilation-related changes are referred to as micromechanics. In lung diseases, abnormalities in acinar micromechanics can be linked with injurious stresses and strains acting on the blood-gas barrier. The mechanisms by which interalveolar septa and the blood-gas barrier adapt to an increase in alveolar volume have been suggested to include unfolding, stretching, or changes in shape other than stretching and unfolding. Folding results in the formation of pleats in which alveolar epithelium is not exposed to air and parts of the blood-gas barrier are folded on each other. The opening of a collapsed alveolus (recruitment) can be considered as an extreme variant of septal wall unfolding. Alveolar recruitment can be detected with imaging techniques which achieve light microscopic resolution. Unfolding of pleats and stretching of the blood-gas barrier, however, require electron microscopic resolution to identify the basement membrane. While stretching results in an increase of the area of the basement membrane, unfolding of pleats and shape changes do not. Real time visualization of these processes, however, is currently not possible. In this review we provide an overview of septal wall micromechanics with focus on unfolding/folding as well as stretching. At the same time we provide a state-of-the-art design-based stereology methodology to quantify microarchitecture of alveoli and interalveolar septa based on different imaging techniques and design-based stereology.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research (DZL), Hannover, Germany
| | - Benjamin Hummel
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Richard Zimmermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Carrie E Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, United States
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering Design and Computing, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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6
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Nelson TM, Quiros KAM, Dominguez EC, Ulu A, Nordgren TM, Eskandari M. Diseased and healthy murine local lung strains evaluated using digital image correlation. Sci Rep 2023; 13:4564. [PMID: 36941463 PMCID: PMC10026788 DOI: 10.1038/s41598-023-31345-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/09/2023] [Indexed: 03/22/2023] Open
Abstract
Tissue remodeling in pulmonary disease irreversibly alters lung functionality and impacts quality of life. Mechanical ventilation is amongst the few pulmonary interventions to aid respiration, but can be harmful or fatal, inducing excessive regional (i.e., local) lung strains. Previous studies have advanced understanding of diseased global-level lung response under ventilation, but do not adequately capture the critical local-level response. Here, we pair a custom-designed pressure-volume ventilator with new applications of digital image correlation, to directly assess regional strains in the fibrosis-induced ex-vivo mouse lung, analyzed via regions of interest. We discuss differences between diseased and healthy lung mechanics, such as distensibility, heterogeneity, anisotropy, alveolar recruitment, and rate dependencies. Notably, we compare local and global compliance between diseased and healthy states by assessing the evolution of pressure-strain and pressure-volume curves resulting from various ventilation volumes and rates. We find fibrotic lungs are less-distensible, with altered recruitment behaviors and regional strains, and exhibit disparate behaviors between local and global compliance. Moreover, these diseased characteristics show volume-dependence and rate trends. Ultimately, we demonstrate how fibrotic lungs may be particularly susceptible to damage when contrasted to the strain patterns of healthy counterparts, helping to advance understanding of how ventilator induced lung injury develops.
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Affiliation(s)
- T M Nelson
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - K A M Quiros
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - E C Dominguez
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA
| | - A Ulu
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
| | - T M Nordgren
- Division of Biomedical Sciences, Riverside School of Medicine, University of California, Riverside, CA, USA
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - M Eskandari
- Department of Mechanical Engineering, University of California, Riverside, CA, USA.
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA.
- Department of Bioengineering, University of California, Riverside, CA, USA.
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7
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Bhana RH, Magan AB. Lung Mechanics: A Review of Solid Mechanical Elasticity in Lung Parenchyma. JOURNAL OF ELASTICITY 2023; 153:53-117. [PMID: 36619653 PMCID: PMC9808719 DOI: 10.1007/s10659-022-09973-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
The lung is the main organ of the respiratory system. Its purpose is to facilitate gas exchange (breathing). Mechanically, breathing may be described as the cyclic application of stresses acting upon the lung surface. These forces are offset by prominent stress-bearing components of lung tissue. These components result from the mechanical elastic properties of lung parenchyma. Various studies have been dedicated to understanding the macroscopic behaviour of parenchyma. This has been achieved through pressure-volume analysis, numerical methods, the development of constitutive equations or strain-energy functions, finite element methods, image processing and elastography. Constitutive equations can describe the elastic behaviour exhibited by lung parenchyma through the relationship between the macroscopic stress and strain. The research conducted within lung mechanics around the elastic and resistive properties of the lung has allowed scientists to develop new methods and equipment for evaluating and treating pulmonary pathogens. This paper establishes a review of mathematical studies conducted within lung mechanics, centering on the development and implementation of solid mechanics to the understanding of the mechanical properties of the lung. Under the classical theory of elasticity, the lung is said to behave as an isotropic elastic continuum undergoing small deformations. However, the lung has also been known to display heterogeneous anisotropic behaviour associated with large deformations. Therefore, focus is placed on the assumptions and development of the various models, their mechanical influence on lung physiology, and the development of constitutive equations through the classical and non-classical theory of elasticity. Lastly, we also look at lung blast mechanics. No explicit emphasis is placed on lung pathology.
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Affiliation(s)
- R. H. Bhana
- School of Computer Science and Applied Mathematics, University of the Witwatersrand, Johannesburg, Wits, 2050 South Africa
| | - A. B. Magan
- School of Computer Science and Applied Mathematics, University of the Witwatersrand, Johannesburg, Wits, 2050 South Africa
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8
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Nelson TM, Quiros KAM, Mariano CA, Sattari S, Ulu A, Dominguez EC, Nordgren TM, Eskandari M. Associating local strains to global pressure-volume mouse lung mechanics using digital image correlation. Physiol Rep 2022; 10:e15466. [PMID: 36207795 PMCID: PMC9547081 DOI: 10.14814/phy2.15466] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/22/2022] [Accepted: 08/28/2022] [Indexed: 12/24/2022] Open
Abstract
Pulmonary diseases alter lung mechanical properties, can cause loss of function, and necessitate use of mechanical ventilation, which can be detrimental. Investigations of lung tissue (local) scale mechanical properties are sparse compared to that of the whole organ (global) level, despite connections between regional strain injury and ventilation. We examine ex vivo mouse lung mechanics by investigating strain values, local compliance, tissue surface heterogeneity, and strain evolutionary behavior for various inflation rates and volumes. A custom electromechanical, pressure-volume ventilator is coupled with digital image correlation to measure regional lung strains and associate local to global mechanics by analyzing novel pressure-strain evolutionary measures. Mean strains at 5 breaths per minute (BPM) for applied volumes of 0.3, 0.5, and 0.7 ml are 5.0, 7.8, and 11.3%, respectively, and 4.7, 8.8, and 12.2% for 20 BPM. Similarly, maximum strains among all rate and volume combinations range 10.7%-22.4%. Strain values (mean, range, mode, and maximum) at peak inflation often exhibit significant volume dependencies. Additionally, select evolutionary behavior (e.g., local lung compliance quantification) and tissue heterogeneity show significant volume dependence. Rate dependencies are generally found to be insignificant; however, strain values and surface lobe heterogeneity tend to increase with increasing rates. By quantifying strain evolutionary behavior in relation to pressure-volume measures, we associate time-continuous local to global mouse lung mechanics for the first time and further examine the role of volume and rate dependency. The interplay of multiscale deformations evaluated in this work can offer insights for clinical applications, such as ventilator-induced lung injury.
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Affiliation(s)
- Talyah M. Nelson
- Department of Mechanical EngineeringUniversity of CaliforniaRiversideCaliforniaUSA
| | | | - Crystal A. Mariano
- Department of Mechanical EngineeringUniversity of CaliforniaRiversideCaliforniaUSA
| | - Samaneh Sattari
- Department of Mechanical EngineeringUniversity of CaliforniaRiversideCaliforniaUSA
| | - Arzu Ulu
- BREATHE CenterSchool of Medicine University of CaliforniaRiversideCaliforniaUSA,Division of Biomedical SciencesSchool of Medicine, University of CaliforniaRiversideCaliforniaUSA
| | - Edward C. Dominguez
- BREATHE CenterSchool of Medicine University of CaliforniaRiversideCaliforniaUSA,Division of Biomedical SciencesSchool of Medicine, University of CaliforniaRiversideCaliforniaUSA
| | - Tara M. Nordgren
- BREATHE CenterSchool of Medicine University of CaliforniaRiversideCaliforniaUSA,Division of Biomedical SciencesSchool of Medicine, University of CaliforniaRiversideCaliforniaUSA
| | - Mona Eskandari
- Department of Mechanical EngineeringUniversity of CaliforniaRiversideCaliforniaUSA,BREATHE CenterSchool of Medicine University of CaliforniaRiversideCaliforniaUSA,Department of BioengineeringUniversity of CaliforniaRiversideCaliforniaUSA
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9
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Zitnay RG, Herron MR, Carney KR, Potter S, Emerson LL, Weiss JA, Mendoza MC. Mechanics of lung cancer: A finite element model shows strain amplification during early tumorigenesis. PLoS Comput Biol 2022; 18:e1010153. [PMID: 36279309 PMCID: PMC9632844 DOI: 10.1371/journal.pcbi.1010153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 11/03/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022] Open
Abstract
Early lung cancer lesions develop within a unique microenvironment that undergoes constant cyclic stretch from respiration. While tumor stiffening is an established driver of tumor progression, the contribution of stress and strain to lung cancer is unknown. We developed tissue scale finite element models of lung tissue to test how early lesions alter respiration-induced strain. We found that an early tumor, represented as alveolar filling, amplified the strain experienced in the adjacent alveolar walls. Tumor stiffening further increased the amplitude of the strain in the adjacent alveolar walls and extended the strain amplification deeper into the normal lung. In contrast, the strain experienced in the tumor proper was less than the applied strain, although regions of amplification appeared at the tumor edge. Measurements of the alveolar wall thickness in clinical and mouse model samples of lung adenocarcinoma (LUAD) showed wall thickening adjacent to the tumors, consistent with cellular response to strain. Modeling alveolar wall thickening by encircling the tumor with thickened walls moved the strain amplification radially outward, to the next adjacent alveolus. Simulating iterative thickening in response to amplified strain produced tracks of thickened walls. We observed such tracks in early-stage clinical samples. The tracks were populated with invading tumor cells, suggesting that strain amplification in very early lung lesions could guide pro-invasive remodeling of the tumor microenvironment. The simulation results and tumor measurements suggest that cells at the edge of a lung tumor and in surrounding alveolar walls experience increased strain during respiration that could promote tumor progression.
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Affiliation(s)
- Rebecca G. Zitnay
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
- Huntsman Cancer Institute, Salt Lake City, Utah, United States of America
| | - Michael R. Herron
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Keith R. Carney
- Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Scott Potter
- Huntsman Cancer Institute, Salt Lake City, Utah, United States of America
- Department of Pathology, University of Utah, Salt Lake City, Utah, United States of America
| | - Lyska L. Emerson
- Huntsman Cancer Institute, Salt Lake City, Utah, United States of America
- Department of Pathology, University of Utah, Salt Lake City, Utah, United States of America
| | - Jeffrey A. Weiss
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
- Scientific Computing and Imaging Institute, Salt Lake City, Utah, United States of America
| | - Michelle C. Mendoza
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
- Huntsman Cancer Institute, Salt Lake City, Utah, United States of America
- Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
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10
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Mukhina E, Trebbi A, Rohan PY, Connesson N, Payan Y. In vivo quantification of 3D displacement in sacral soft tissues under compression: Relevance of 2D US-based measurements for pressure ulcer risk assessment. J Tissue Viability 2022; 31:593-600. [DOI: 10.1016/j.jtv.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 11/17/2022]
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11
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Mariano CA, Sattari S, Quiros KAM, Nelson TM, Eskandari M. Examining lung mechanical strains as influenced by breathing volumes and rates using experimental digital image correlation. Respir Res 2022; 23:92. [PMID: 35410291 PMCID: PMC8999998 DOI: 10.1186/s12931-022-01999-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 03/18/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Mechanical ventilation is often employed to facilitate breathing in patients suffering from respiratory illnesses and disabilities. Despite the benefits, there are risks associated with ventilator-induced lung injuries and death, driving investigations for alternative ventilation techniques to improve mechanical ventilation, such as multi-oscillatory and high-frequency ventilation; however, few studies have evaluated fundamental lung mechanical local deformations under variable loading. METHODS Porcine whole lung samples were analyzed using a novel application of digital image correlation interfaced with an electromechanical ventilation system to associate the local behavior to the global volume and pressure loading in response to various inflation volumes and breathing rates. Strains, anisotropy, tissue compliance, and the evolutionary response of the inflating lung were analyzed. RESULTS Experiments demonstrated a direct and near one-to-one linear relationship between applied lung volumes and resulting local mean strain, and a nonlinear relationship between lung pressures and strains. As the applied air delivery volume was doubled, the tissue surface mean strains approximately increased from 20 to 40%, and average maximum strains measured 70-110%. The tissue strain anisotropic ratio ranged from 0.81 to 0.86 and decreased with greater inflation volumes. Local tissue compliance during the inflation cycle, associating evolutionary strains in response to inflation pressures, was also quantified. CONCLUSION Ventilation frequencies were not found to influence the local stretch response. Strain measures significantly increased and the anisotropic ratio decreased between the smallest and greatest tidal volumes. Tissue compliance did not exhibit a unifying trend. The insights provided by the real-time continuous measures, and the kinetics to kinematics pulmonary linkage established by this study offers valuable characterizations for computational models and establishes a framework for future studies to compare healthy and diseased lung mechanics to further consider alternatives for effective ventilation strategies.
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Affiliation(s)
- C A Mariano
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA
| | - S Sattari
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA
| | - K A M Quiros
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA
| | - T M Nelson
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA
| | - M Eskandari
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA.
- BREATHE Center, School of Medicine, University of California at Riverside, Riverside, CA, USA.
- Department of Bioengineering, University of California at Riverside, Riverside, CA, USA.
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12
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Maghsoudi-Ganjeh M, Mariano CA, Sattari S, Arora H, Eskandari M. Developing a Lung Model in the Age of COVID-19: A Digital Image Correlation and Inverse Finite Element Analysis Framework. Front Bioeng Biotechnol 2021; 9:684778. [PMID: 34765590 PMCID: PMC8576180 DOI: 10.3389/fbioe.2021.684778] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/04/2021] [Indexed: 02/02/2023] Open
Abstract
Pulmonary diseases, driven by pollution, industrial farming, vaping, and the infamous COVID-19 pandemic, lead morbidity and mortality rates worldwide. Computational biomechanical models can enhance predictive capabilities to understand fundamental lung physiology; however, such investigations are hindered by the lung’s complex and hierarchical structure, and the lack of mechanical experiments linking the load-bearing organ-level response to local behaviors. In this study we address these impedances by introducing a novel reduced-order surface model of the lung, combining the response of the intricate bronchial network, parenchymal tissue, and visceral pleura. The inverse finite element analysis (IFEA) framework is developed using 3-D digital image correlation (DIC) from experimentally measured non-contact strains and displacements from an ex-vivo porcine lung specimen for the first time. A custom-designed inflation device is employed to uniquely correlate the multiscale classical pressure-volume bulk breathing measures to local-level deformation topologies and principal expansion directions. Optimal material parameters are found by minimizing the error between experimental and simulation-based lung surface displacement values, using both classes of gradient-based and gradient-free optimization algorithms and by developing an adjoint formulation for efficiency. The heterogeneous and anisotropic characteristics of pulmonary breathing are represented using various hyperelastic continuum formulations to divulge compound material parameters and evaluate the best performing model. While accounting for tissue anisotropy with fibers assumed along medial-lateral direction did not benefit model calibration, allowing for regional material heterogeneity enabled accurate reconstruction of lung deformations when compared to the homogeneous model. The proof-of-concept framework established here can be readily applied to investigate the impact of assorted organ-level ventilation strategies on local pulmonary force and strain distributions, and to further explore how diseased states may alter the load-bearing material behavior of the lung. In the age of a respiratory pandemic, advancing our understanding of lung biomechanics is more pressing than ever before.
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Affiliation(s)
- Mohammad Maghsoudi-Ganjeh
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Crystal A Mariano
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Samaneh Sattari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Hari Arora
- Faculty of Science and Engineering, Swansea University, Swansea, United Kingdom
| | - Mona Eskandari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States.,BREATHE Center, School of Medicine, University of California, Riverside, Riverside, CA, United States.,Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
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13
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Novak C, Ballinger MN, Ghadiali S. Mechanobiology of Pulmonary Diseases: A Review of Engineering Tools to Understand Lung Mechanotransduction. J Biomech Eng 2021; 143:110801. [PMID: 33973005 PMCID: PMC8299813 DOI: 10.1115/1.4051118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/01/2021] [Indexed: 12/17/2022]
Abstract
Cells within the lung micro-environment are continuously subjected to dynamic mechanical stimuli which are converted into biochemical signaling events in a process known as mechanotransduction. In pulmonary diseases, the abrogated mechanical conditions modify the homeostatic signaling which influences cellular phenotype and disease progression. The use of in vitro models has significantly expanded our understanding of lung mechanotransduction mechanisms. However, our ability to match complex facets of the lung including three-dimensionality, multicellular interactions, and multiple simultaneous forces is limited and it has proven difficult to replicate and control these factors in vitro. The goal of this review is to (a) outline the anatomy of the pulmonary system and the mechanical stimuli that reside therein, (b) describe how disease impacts the mechanical micro-environment of the lung, and (c) summarize how existing in vitro models have contributed to our current understanding of pulmonary mechanotransduction. We also highlight critical needs in the pulmonary mechanotransduction field with an emphasis on next-generation devices that can simulate the complex mechanical and cellular environment of the lung. This review provides a comprehensive basis for understanding the current state of knowledge in pulmonary mechanotransduction and identifying the areas for future research.
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Affiliation(s)
- Caymen Novak
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University, Wexner Medical Center, 473 West 12th Avenue, Columbus, OH 43210
| | - Megan N. Ballinger
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University, Wexner Medical Center, 473 West 12th Avenue, Columbus, OH 43210
| | - Samir Ghadiali
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University, Wexner Medical Center, 473 West 12th Avenue, Columbus, OH 43210; Department of Biomedical Engineering, The Ohio State University, 2124N Fontana Labs, 140 West 19th Avenue, Columbus, OH 43210
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Kolb P, Schundner A, Frick M, Gottschalk KE. In Vitro Measurements of Cellular Forces and their Importance in the Lung-From the Sub- to the Multicellular Scale. Life (Basel) 2021; 11:691. [PMID: 34357063 PMCID: PMC8307149 DOI: 10.3390/life11070691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/09/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
Throughout life, the body is subjected to various mechanical forces on the organ, tissue, and cellular level. Mechanical stimuli are essential for organ development and function. One organ whose function depends on the tightly connected interplay between mechanical cell properties, biochemical signaling, and external forces is the lung. However, altered mechanical properties or excessive mechanical forces can also drive the onset and progression of severe pulmonary diseases. Characterizing the mechanical properties and forces that affect cell and tissue function is therefore necessary for understanding physiological and pathophysiological mechanisms. In recent years, multiple methods have been developed for cellular force measurements at multiple length scales, from subcellular forces to measuring the collective behavior of heterogeneous cellular networks. In this short review, we give a brief overview of the mechanical forces at play on the cellular level in the lung. We then focus on the technological aspects of measuring cellular forces at many length scales. We describe tools with a subcellular resolution and elaborate measurement techniques for collective multicellular units. Many of the technologies described are by no means restricted to lung research and have already been applied successfully to cells from various other tissues. However, integrating the knowledge gained from these multi-scale measurements in a unifying framework is still a major future challenge.
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Affiliation(s)
- Peter Kolb
- Institute of Experimental Physics, Ulm University, 89069 Ulm, Germany;
| | - Annika Schundner
- Institute of General Physiology, Ulm University, 89069 Ulm, Germany;
| | - Manfred Frick
- Institute of General Physiology, Ulm University, 89069 Ulm, Germany;
| | - Kay-E. Gottschalk
- Institute of Experimental Physics, Ulm University, 89069 Ulm, Germany;
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