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Wu Z, Jiang J, Lischka FW, Zhao K. Is the mouse nose a miniature version of a rat nose? A computational comparative study. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 254:108282. [PMID: 38878359 DOI: 10.1016/j.cmpb.2024.108282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/21/2024] [Accepted: 06/07/2024] [Indexed: 07/28/2024]
Abstract
BACKGROUND AND OBJECTIVE Although the mouse is a widely used animal model in biomedical research, there are few published studies on its nasal aerodynamics, potentially due to its small size. It is not appropriate to assume that mice and rats' nasal structure and airflow characteristics are the same because the ratio of nasal surface area to nasal volume and body weight is much higher in a mouse than in a rat. The aim of this work is to use anatomically accurate image-based computational fluid dynamic modeling to quantitatively reveal the characteristics of mouse nasal airflow and mass transport that haven't been detailed before and find key differences to that of rat nose, which will deepen our understanding of the mouse's physiological functions. METHODS We created an anatomically accurate 3D computational nasal model of a B6 mouse using postmortem high-resolution micro-CT scans and simulated the airflow distribution and odor transport patterns under restful breathing conditions. The deposition pattern of airborne particles was also simulated and validated against experimental data. In addition, we calculated the gas chromatograph efficiency of odor transport in the mouse employing the theoretical plate concept and compared it with previous studies involving cat and rat models. RESULTS Similar to the published rat model, respiratory and olfactory flow regimes are clearly separated in the mouse nasal cavity. A high-speed dorsal medial (DM) stream was observed, which enhances the delivery speed and efficiency of odor to the ethmoid (olfactory) recess (ER). The DM stream split into axial and secondary paths in the ER. However, the secondary flow in the mouse is less extensive than in the rat. The gas chromatograph efficiency calculations suggest that the rat may possess a moderately higher odorant transport efficiency than that of the mouse due to its more complex ethmoid recess structure and extensive secondary flow. However, the mouse's nasal structure seems to adapt better to varying airflow velocity. CONCLUSIONS Due to the inherent structural disparities, the rat and mouse models exhibit moderate differences in airflow and mass transport patterns, potentially impacting their olfaction and other behavioral habits.
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Affiliation(s)
- Zhenxing Wu
- Department of Otolaryngology-Head & Neck Surgery, the Ohio State University, 915 Olentangy River Road, Columbus, OH 43212, United States of America
| | - Jianbo Jiang
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
| | - Fritz W Lischka
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
| | - Kai Zhao
- Department of Otolaryngology-Head & Neck Surgery, the Ohio State University, 915 Olentangy River Road, Columbus, OH 43212, United States of America.
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Xi J, Si XA, Malvè M. Nasal anatomy and sniffing in respiration and olfaction of wild and domestic animals. Front Vet Sci 2023; 10:1172140. [PMID: 37520001 PMCID: PMC10375297 DOI: 10.3389/fvets.2023.1172140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 06/29/2023] [Indexed: 08/01/2023] Open
Abstract
Animals have been widely utilized as surrogate models for humans in exposure testing, infectious disease experiments, and immunology studies. However, respiratory diseases affect both humans and animals. These disorders can spontaneously affect wild and domestic animals, impacting their quality and quantity of life. The origin of such responses can primarily be traced back to the pathogens deposited in the respiratory tract. There is a lack of understanding of the transport and deposition of respirable particulate matter (bio-aerosols or viruses) in either wild or domestic animals. Moreover, local dosimetry is more relevant than the total or regionally averaged doses in assessing exposure risks or therapeutic outcomes. An accurate prediction of the total and local dosimetry is the crucial first step to quantifying the dose-response relationship, which in turn necessitates detailed knowledge of animals' respiratory tract and flow/aerosol dynamics within it. In this review, we examined the nasal anatomy and physiology (i.e., structure-function relationship) of different animals, including the dog, rat, rabbit, deer, rhombus monkey, cat, and other domestic and wild animals. Special attention was paid to the similarities and differences in the vestibular, respiratory, and olfactory regions among different species. The ventilation airflow and behaviors of inhaled aerosols were described as pertinent to the animals' mechanisms for ventilation modulation and olfaction enhancement. In particular, sniffing, a breathing maneuver that animals often practice enhancing olfaction, was examined in detail in different animals. Animal models used in COVID-19 research were discussed. The advances and challenges of using numerical modeling in place of animal studies were discussed. The application of this technique in animals is relevant for bidirectional improvements in animal and human health.
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Affiliation(s)
- Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, United States
| | - Xiuhua April Si
- Department of Mechanical Engineering, California Baptist University, Riverside, CA, United States
| | - Mauro Malvè
- Department of Engineering, Public University of Navarre, Pamplona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
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WEI Y, HORI A, CHEN IY, TAMOGI H, HIROKAWA T, KATO K, ITAMI T, SANO T, YAMASHITA K. Maximum volume of nasal administration using a mucosal atomization device without aspiration in Japanese White rabbits. J Vet Med Sci 2022; 84:792-798. [PMID: 35400673 PMCID: PMC9246693 DOI: 10.1292/jvms.21-0648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, a mucosal atomization device (MAD) has been applied in veterinary medicine. In
the present study, the maximum volume of nasal atomization without aspiration using MAD
was examined in eight healthy female Japanese White (JW) rabbits. Each rabbit had their
head and neck examined by computed tomography before and after nasal atomization with four
different doses (0.15, 0.3, 0.45, and 0.6 ml per nostril) of diluted contrast medium (1:2
mixture of iohexol and saline). This was done under general anesthesia by an intramuscular
administration of alfaxalone 2.5 mg/kg, medetomidine 40 μg/kg, and butorphanol 0.4 mg/kg,
with a 7-day washout period between each treatment. The diluted contrast medium was
distributed in the nasal cavity, external nares, and/or oral cavity in all rabbits
receiving each treatment. The intranasal distribution volumes of the contrast medium were
287 (250–333) mm3 [median (interquartile range)] for 0.15 ml, 433 (243–555)
mm3 for 0.3 ml, 552 (356–797) mm3 for 0.45 ml, and 529 (356–722)
mm3 for 0.6 ml of treatment. The intranasal distribution volume for 0.15 ml
treatment tended to be lower than that for 0.6 ml treatment (P=0.083).
The contrast medium was deposited in the trachea in one rabbit (12.5%) and four rabbits
(50%) receiving treatments of 0.45 and 0.6 ml per nostril, respectively. The maximum
volume of nasal atomization without aspiration into the trachea was 0.3 ml per nostril for
the JW rabbits.
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Affiliation(s)
- Yixian WEI
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Ai HORI
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - I-Ying CHEN
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Haruka TAMOGI
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Taku HIROKAWA
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Keiko KATO
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Takaharu ITAMI
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Tadashi SANO
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
| | - Kazuto YAMASHITA
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University
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Dogra P, Butner JD, Nizzero S, Ruiz Ramírez J, Noureddine A, Peláez MJ, Elganainy D, Yang Z, Le AD, Goel S, Leong HS, Koay EJ, Brinker CJ, Cristini V, Wang Z. Image-guided mathematical modeling for pharmacological evaluation of nanomaterials and monoclonal antibodies. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2020; 12:e1628. [PMID: 32314552 PMCID: PMC7507140 DOI: 10.1002/wnan.1628] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/06/2020] [Accepted: 02/15/2020] [Indexed: 12/13/2022]
Abstract
While plasma concentration kinetics has traditionally been the predictor of drug pharmacological effects, it can occasionally fail to represent kinetics at the site of action, particularly for solid tumors. This is especially true in the case of delivery of therapeutic macromolecules (drug-loaded nanomaterials or monoclonal antibodies), which can experience challenges to effective delivery due to particle size-dependent diffusion barriers at the target site. As a result, disparity between therapeutic plasma kinetics and kinetics at the site of action may exist, highlighting the importance of target site concentration kinetics in determining the pharmacodynamic effects of macromolecular therapeutic agents. Assessment of concentration kinetics at the target site has been facilitated by non-invasive in vivo imaging modalities. This allows for visualization and quantification of the whole-body disposition behavior of therapeutics that is essential for a comprehensive understanding of their pharmacokinetics and pharmacodynamics. Quantitative non-invasive imaging can also help guide the development and parameterization of mathematical models for descriptive and predictive purposes. Here, we present a review of the application of state-of-the-art imaging modalities for quantitative pharmacological evaluation of therapeutic nanoparticles and monoclonal antibodies, with a focus on their integration with mathematical models, and identify challenges and opportunities. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.
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Affiliation(s)
- Prashant Dogra
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Joseph D Butner
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Sara Nizzero
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Javier Ruiz Ramírez
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Achraf Noureddine
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico, USA
| | - María J Peláez
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA.,Applied Physics Graduate Program, Rice University, Houston, Texas, USA
| | - Dalia Elganainy
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Zhen Yang
- Center for Bioenergetics, Houston Methodist Research Institute, Houston, Texas, USA
| | - Anh-Dung Le
- Nanoscience and Microsystems Engineering, University of New Mexico, Albuquerque, New Mexico, USA
| | - Shreya Goel
- Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Hon S Leong
- Biological Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Eugene J Koay
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - C Jeffrey Brinker
- Department of Chemical and Biological Engineering and UNM Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico, USA
| | - Vittorio Cristini
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Zhihui Wang
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
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Xi J, Talaat M, Si X, Dong H, Donepudi R, Kabilan S, Corley R. Ventilation Modulation and Nanoparticle Deposition in Respiratory and Olfactory Regions of Rabbit Nose. Animals (Basel) 2019; 9:E1107. [PMID: 31835419 PMCID: PMC6940773 DOI: 10.3390/ani9121107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/22/2019] [Accepted: 12/05/2019] [Indexed: 12/05/2022] Open
Abstract
The rabbit nose's ability to filter out inhaled agents is directly related to its defense to infectious diseases. The knowledge of the rabbit nose anatomy is essential to appreciate its functions in ventilation regulation, aerosol filtration and olfaction. The objective of this study is to numerically simulate the inhalation and deposition of nanoparticles in a New Zealand white (NZW) rabbit nose model with an emphasis on the structure-function relation under normal and sniffing conditions. To simulate the sniffing scenario, the original nose model was modified to generate new models with enlarged nostrils or vestibules based on video images of a rabbit sniffing. Ventilations into the maxilloturbinate and olfactory region were quantified with varying nostril openings, and deposition rates of inhaled aerosols ranging from 0.5 nm to 1000 nm were characterized on the total, sub-regional and local basis. Results showed that particles which deposited in the olfactory region came from a specific area in the nostril. The spiral vestibule played an essential role in regulating flow resistance and flow partition into different parts of the nose. Increased olfactory doses were persistently predicted in models with expanded nostrils or vestibule. Particles in the range of 5-50 nm are more sensitive to the geometry variation than other nanoparticles. It was also observed that exhaled aerosols occupy only the central region of the nostril, which minimized the mixing with the aerosols close to the nostril wall, and potentially allowed the undisruptive sampling of odorants. The results of this study shed new light on the ventilation regulation and inhalation dosimetry in the rabbit nose, which can be further implemented to studies of infectious diseases and immunology in rabbits.
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Affiliation(s)
- Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA 01854, USA;
| | - Mohamed Talaat
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA 01854, USA;
| | - Xiuhua Si
- Department of Aerospace, Industrial, and Mechanical Engineering, California Baptist University, Riverside, CA 91752, USA;
| | - Haibo Dong
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22903, USA;
| | - Ramesh Donepudi
- Sleep and Neurodiagnostic Center, Lowell General Hospital, Lowell, MA 01854, USA;
| | | | - Richard Corley
- Greek Creek Toxicokinetics Consulting, LLC, Boise, ID 83701, USA;
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Abstract
The available toxicity data of benzalkonium chloride (BKC) clearly shows that it is toxic; however, the weight of evidence favors the view that at doses encountered in nasally and orally inhaled pharmaceutical preparations it is well tolerated. The adverse toxicological data predominantly come from in vitro and animal studies in which doses and exposure periods employed were excessive in relation to the clinical doses and their posology and, therefore, not directly applicable to the clinic. The conflict between the in vitro and animal data and the clinical experience can be reconciled by understanding some of the physicochemical properties of BKC, the nasal and respiratory tract microenvironments, the doses used, and the posology.
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Affiliation(s)
- Neil F Johnson
- Pharma Toxicology Safety Solutions LLC , Highland Park, Illinois
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7
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Xi J, Si XA, Kim J, Zhang Y, Jacob RE, Kabilan S, Corley RA. Anatomical Details of the Rabbit Nasal Passages and Their Implications in Breathing, Air Conditioning, and Olfaction. Anat Rec (Hoboken) 2016; 299:853-68. [PMID: 27145450 DOI: 10.1002/ar.23367] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 03/21/2016] [Accepted: 03/29/2016] [Indexed: 12/22/2022]
Abstract
The rabbit is commonly used as a laboratory animal for inhalation toxicology tests and detail knowledge of the rabbit airway morphometry is needed for outcome analysis or theoretical modeling. The objective of this study is to quantify the morphometric dimension of the nasal airway of a New Zealand white rabbit and to relate the morphology and functions through analytical and computational methods. Images of high-resolution MRI scans of the rabbit were processed to measure the axial distribution of the cross-sectional areas, perimeter, and complexity level. The lateral recess, which has functions other than respiration or olfaction, was isolated from the nasal airway and its dimension was quantified separately. A low Reynolds number turbulence model was implemented to simulate the airflow, heat transfer, vapor transport, and wall shear stress. Results of this study provide detailed morphological information of the rabbit that can be used in the studies of olfaction, inhalation toxicology, drug delivery, and physiology-based pharmacokinetics modeling. For the first time, we reported a spiral nasal vestibule that splits into three paths leading to the dorsal meatus, maxilloturbinate, and ventral meatus, respectively. Both non-dimensional functional analysis and CFD simulations suggested that the airflow in the rabbit nose is laminar and the unsteady effect is only significantly during sniffing. Due to the large surface-to-volume ratio, the maxilloturbinate is highly effective in warming and moistening the inhaled air to body conditions. The unique anatomical structure and respiratory airflow pattern may have important implications for designing new odorant detectors or electronic noses. Anat Rec, 299:853-868, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jinxiang Xi
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, Michigan
| | - Xiuhua A Si
- Department of Mechanical Engineering, California Baptist University, Riverside, California
| | - Jongwon Kim
- College of Engineering, University of Georgia, Athens, Georgia
| | - Yu Zhang
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, Michigan
| | - Richard E Jacob
- Systems Toxicology & Exposure Science, Pacific Northwest National Laboratory, Richland, Washington
| | - Senthil Kabilan
- Systems Toxicology & Exposure Science, Pacific Northwest National Laboratory, Richland, Washington
| | - Richard A Corley
- Systems Toxicology & Exposure Science, Pacific Northwest National Laboratory, Richland, Washington
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8
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Van Valkenburgh B, Smith TD, Craven BA. Tour of a labyrinth: exploring the vertebrate nose. Anat Rec (Hoboken) 2015; 297:1975-84. [PMID: 25312359 DOI: 10.1002/ar.23021] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 01/18/2023]
Abstract
This special issue of The Anatomical Record is the outcome of a symposium entitled "Inside the Vertebrate Nose: Evolution, Structure and Function." The skeletal framework of the nasal cavity is a complicated structure that often houses sinuses and comprises an internal skeleton of bone or cartilage that can vary greatly in architecture among species. The nose serves multiple functions, including olfaction and respiratory air-conditioning, and its morphology is constrained by evolution, development, and conflicting demands on cranial space, such as enlarged orbits. The nasal cavity of vertebrates has received much more attention in the last decade due to the emergence of nondestructive methods that allow improved visualization of the internal anatomy of the skull, such as high-resolution x-ray computed tomography and magnetic resonance imaging. The 17 articles included here represent a broad range of investigators, from paleontologists to engineers, who approach the nose from different perspectives. Key topics include the evolution and development of the nose, its comparative anatomy and function, and airflow through the nasal cavity of individual species. In addition, this special issue includes review articles on anatomical reduction of the olfactory apparatus in both cetaceans and primates (the vomeronasal system), as well as the molecular biology of olfaction in vertebrates. Together these articles provide an expansive summary of our current understanding of vertebrate nasal anatomy and function. In this introduction, we provide background information and an overview of each of the three primary topics, and place each article within the context of previous research and the major challenges that lie ahead.
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Wei Z, Xu Z, Li B, Xu F. Numerical simulation of airway dimension effects on airflow patterns and odorant deposition patterns in the rat nasal cavity. PLoS One 2013; 8:e77570. [PMID: 24204875 PMCID: PMC3810392 DOI: 10.1371/journal.pone.0077570] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 09/04/2013] [Indexed: 11/27/2022] Open
Abstract
The sense of smell is largely dependent on the airflow and odorant transport in the nasal cavity, which in turn depends on the anatomical structure of the nose. In order to evaluate the effect of airway dimension on rat nasal airflow patterns and odorant deposition patterns, we constructed two 3-dimensional, anatomically accurate models of the left nasal cavity of a Sprague-Dawley rat: one was based on high-resolution MRI images with relatively narrow airways and the other was based on artificially-widening airways of the MRI images by referencing the section images with relatively wide airways. Airflow and odorant transport, in the two models, were determined using the method of computational fluid dynamics with finite volume method. The results demonstrated that an increase of 34 µm in nasal airway dimension significantly decreased the average velocity in the whole nasal cavity by about 10% and in the olfactory region by about 12% and increased the volumetric flow into the olfactory region by about 3%. Odorant deposition was affected to a larger extent, especially in the olfactory region, where the maximum odorant deposition difference reached one order of magnitude. The results suggest that a more accurate nasal cavity model is necessary in order to more precisely study the olfactory function of the nose when using the rat.
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Affiliation(s)
- Zehong Wei
- Division of Biomedical Photonics, Wuhan National Laboratory of Optoelectronics, Wuhan, China
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Zhixiang Xu
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Bo Li
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Fuqiang Xu
- Division of Biomedical Photonics, Wuhan National Laboratory of Optoelectronics, Wuhan, China
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
- * E-mail:
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Kuprat A, Kabilan S, Carson J, Corley R, Einstein D. A Bidirectional Coupling Procedure Applied to Multiscale Respiratory Modeling. JOURNAL OF COMPUTATIONAL PHYSICS 2013; 244:10.1016/j.jcp.2012.10.021. [PMID: 24347680 PMCID: PMC3856712 DOI: 10.1016/j.jcp.2012.10.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this study, we present a novel multiscale computational framework for efficiently linking multiple lower-dimensional models describing the distal lung mechanics to imaging-based 3D computational fluid dynamics (CFD) models of the upper pulmonary airways in order to incorporate physiologically appropriate outlet boundary conditions. The framework is an extension of the Modified Newton's Method with nonlinear Krylov accelerator developed by Carlson and Miller [1, 2, 3]. Our extensions include the retention of subspace information over multiple timesteps, and a special correction at the end of a timestep that allows for corrections to be accepted with verified low residual with as little as a single residual evaluation per timestep on average. In the case of a single residual evaluation per timestep, the method has zero additional computational cost compared to uncoupled or unidirectionally coupled simulations. We expect these enhancements to be generally applicable to other multiscale coupling applications where timestepping occurs. In addition we have developed a "pressure-drop" residual which allows for stable coupling of flows between a 3D incompressible CFD application and another (lower-dimensional) fluid system. We expect this residual to also be useful for coupling non-respiratory incompressible fluid applications, such as multiscale simulations involving blood flow. The lower-dimensional models that are considered in this study are sets of simple ordinary differential equations (ODEs) representing the compliant mechanics of symmetric human pulmonary airway trees. To validate the method, we compare the predictions of hybrid CFD-ODE models against an ODE-only model of pulmonary airflow in an idealized geometry. Subsequently, we couple multiple sets of ODEs describing the distal lung to an imaging-based human lung geometry. Boundary conditions in these models consist of atmospheric pressure at the mouth and intrapleural pressure applied to the multiple sets of ODEs. In both the simplified geometry and in the imaging-based geometry, the performance of the method was comparable to that of monolithic schemes, in most cases requiring only a single CFD evaluation per time step. Thus, this new accelerator allows us to begin combining pulmonary CFD models with lower-dimensional models of pulmonary mechanics with little computational overhead. Moreover, because the CFD and lower-dimensional models are totally separate, this framework affords great flexibility in terms of the type and breadth of the adopted lower-dimensional model, allowing the biomedical researcher to appropriately focus on model design. Research funded by the National Heart and Blood Institute Award 1RO1HL073598.
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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: 102] [Impact Index Per Article: 8.5] [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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Abstract
With the ever increasing volume of data available to scientists in drug discovery and development, the opportunity to leverage an increasing amount of these data in the assessment of drug safety is clear. The challenge in an environment of increasing data volume is in the structuring and the analysis of these data, such that decisions can be made without excluding information or overstating their meaning. Informatics and modelling play a crucial role in addressing this challenge in two basic ways: a) the data are structured and analysed in a transparent and objective way; and b) new experiments are designed with the model as part of the design process, much like modern experimental physics. Enhancing the use and impact of informatics and modelling on drug discovery is not simply a matter of increasing processor speed and memory capacity. The transformation of raw data to usable, and useful, information is a scientific, technical and, perhaps most importantly, cultural challenge within drug discovery. This review will highlight some of the history, current approaches and promising future directions in this rapidly expanding area.
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Affiliation(s)
- Scott Boyer
- Global Safety Assessment, AstraZeneca R&D, Mölndal, Sweden.
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