1
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Flanary SM, Peak KE, Barocas VH. A Graphical Approach to Visualize and Interpret Biochemically Coupled Biomechanical Models. J Biomech Eng 2024; 146:054504. [PMID: 38421368 PMCID: PMC11005857 DOI: 10.1115/1.4064970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/02/2024]
Abstract
The last decade has seen the emergence of progressively more complex mechanobiological models, often coupling biochemical and biomechanical components. The complexity of these models makes interpretation difficult, and although computational tools can solve model equations, there is considerable potential value in a simple method to explore the interplay between different model components. Pump and system performance curves, long utilized in centrifugal pump selection and design, inspire the development of a graphical technique to depict visually the performance of biochemically-coupled mechanical models. Our approach is based on a biochemical performance curve (analogous to the classical pump curve) and a biomechanical performance curve (analogous to the system curve). Upon construction of the two curves, their intersection, or lack thereof, describes the coupled model's equilibrium state(s). One can also observe graphically how an applied perturbation shifts one or both curves, and thus how the other component will respond, without rerunning the full model. While the upfront cost of generating the performance curve graphic varies with the efficiency of the model components, the easily interpretable visual depiction of what would otherwise be nonintuitive model behavior is valuable. Herein, we outline how performance curves can be constructed and interpreted for biochemically-coupled biomechanical models and apply the technique to two independent models in the cardiovascular space. The performance curve approach can illustrate and help identify weaknesses in model construction, inform user-applied perturbations and fitting procedures to generate intended behaviors, and improve the efficiency of the model generation and application process.
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Affiliation(s)
- Shannon M. Flanary
- Department of Chemical Engineering & Materials Science, University of Minnesota, Nils Hasselmo Hall, Room 7-115, 312 Church St SE, Minneapolis, MN 55455
| | - Kara E. Peak
- Department of Biomedical Engineering, University of Minnesota, Nils Hasselmo Hall, Room 7-115, 312 Church St SE, Minneapolis, MN 55455
- University of Minnesota
| | - Victor H. Barocas
- Department of Biomedical Engineering, University of Minnesota, Nils Hasselmo Hall, Room 7-115, 312 Church St SE, Minneapolis, MN 55455
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2
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Estrada AC, Irons L, Tellides G, Humphrey JD. Multiscale computational model of aortic remodeling following postnatal disruption of TGFβ signaling. J Biomech 2024; 169:112152. [PMID: 38763809 DOI: 10.1016/j.jbiomech.2024.112152] [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: 12/06/2023] [Revised: 03/20/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
The healthy adult aorta is a remarkably resilient structure, able to resist relentless cardiac-induced and hemodynamic loads under normal conditions. Fundamental to such mechanical homeostasis is the mechano-sensitive cell signaling that controls gene products and thus the structural integrity of the wall. Mouse models have shown that smooth muscle cell-specific disruption of transforming growth factor-beta (TGFβ) signaling during postnatal development compromises this resiliency, rendering the aortic wall susceptible to aneurysm and dissection under normal mechanical loading. By contrast, disruption of such signaling in the adult aorta appears to introduce a vulnerability that remains hidden under normal loading, but manifests under increased loading as experienced during hypertension. We present a multiscale (transcript to tissue) computational model to examine possible reasons for compromised mechanical homeostasis in the adult aorta following reduced TGFβ signaling in smooth muscle cells.
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Affiliation(s)
- Ana C Estrada
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Linda Irons
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - George Tellides
- Department of Surgery, Cardiothoracic, Yale School of Medicine, New Haven, CT, USA; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA.
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3
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Szafron JM, Heng EE, Boyd J, Humphrey JD, Marsden AL. Hemodynamics and Wall Mechanics of Vascular Graft Failure. Arterioscler Thromb Vasc Biol 2024; 44:1065-1085. [PMID: 38572650 PMCID: PMC11043008 DOI: 10.1161/atvbaha.123.318239] [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: 09/04/2023] [Accepted: 03/12/2024] [Indexed: 04/05/2024]
Abstract
Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.
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Affiliation(s)
- Jason M Szafron
- Departments of Pediatrics (J.M.S., A.L.M.), Stanford University, CA
| | - Elbert E Heng
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jack Boyd
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT (J.D.H.)
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4
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Coccarelli A, Van Loon R, Chien A. A Computational Pipeline to Investigate Longitudinal Blood Flow Changes in the Circle of Willis of Patients with Stable and Growing Aneurysms. Ann Biomed Eng 2024:10.1007/s10439-024-03493-1. [PMID: 38616236 DOI: 10.1007/s10439-024-03493-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/10/2024] [Indexed: 04/16/2024]
Abstract
Changes in cerebral blood flow are often associated with the initiation and development of different life-threatening medical conditions including aneurysm rupture and ischemic stroke. Nevertheless, it is not fully clear how haemodynamic changes in time across the Circle of Willis (CoW) are related with intracranial aneurysm (IA) growth. In this work, we introduced a novel reduced-order modelling strategy for the systematic quantification of longitudinal blood flow changes across the whole CoW in patients with stable and unstable/growing aneurysm. Magnetic Resonance Angiography (MRA) images were converted into one-dimensional (1-D) vessel networks through a semi-automated procedure, with a level of geometric reconstruction accuracy controlled by user-dependent parameters. The proposed pipeline was used to systematically analyse longitudinal haemodynamic changes in seven different clinical cases. Our preliminary simulation results indicate that growing aneurysms are not necessarily associated with significant changes in mean flow over time. A concise sensitivity analysis also shed light on which modelling aspects need to be further characterized to have reliable patient-specific predictions. This study poses the basis for investigating how time-dependent changes in the vasculature affect the haemodynamics across the whole CoW in patients with stable and growing aneurysms.
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Affiliation(s)
- Alberto Coccarelli
- Zienkiewicz Institute for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, UK.
- Department of Mechanical Engineering, Faculty of Science and Engineering, Swansea University, Swansea, UK.
| | - Raoul Van Loon
- Zienkiewicz Institute for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Biomedical Engineering Simulation and Testing Lab, Department of Biomedical Engineering, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - Aichi Chien
- Radiological Sciences, School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, USA
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5
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Coccarelli A, Pant S, Polydoros I, Harraz OF. A new model for evaluating pressure-induced vascular tone in small cerebral arteries. Biomech Model Mechanobiol 2024; 23:271-286. [PMID: 37925376 PMCID: PMC10901969 DOI: 10.1007/s10237-023-01774-7] [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: 06/05/2023] [Accepted: 09/17/2023] [Indexed: 11/06/2023]
Abstract
The capacity of small cerebral arteries (SCAs) to adapt to pressure fluctuations has a fundamental physiological role and appears to be relevant in different pathological conditions. Here, we present a new computational model for quantifying the link, and its contributors, between luminal pressure and vascular tone generation in SCAs. This is assembled by combining a chemical sub-model, representing pressure-induced smooth muscle cell (SMC) signalling, with a mechanical sub-model for the tone generation and its transduction at tissue level. The devised model can accurately reproduce the impact of luminal pressure on different cytoplasmic components involved in myogenic signalling, both in the control case and when combined with some specific pharmacological interventions. Furthermore, the model is also able to capture and predict experimentally recorded pressure-outer diameter relationships obtained for vessels under control conditions, both in a Ca2 + -free bath and under drug inhibition. The modularity of the proposed framework allows the integration of new components for the study of a broad range of processes involved in the vascular function.
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Affiliation(s)
- Alberto Coccarelli
- Zienkiewicz Institute for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, UK.
| | - Sanjay Pant
- Zienkiewicz Institute for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - Ioannis Polydoros
- Zienkiewicz Institute for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - Osama F Harraz
- Department of Pharmacology, Larner College of Medicine, and Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, USA
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6
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Uatay A, Gall L, Irons L, Tewari SG, Zhu XS, Gibbs M, Kimko H. Physiological Indirect Response Model to Omics-Powered Quantitative Systems Pharmacology Model. J Pharm Sci 2024; 113:11-21. [PMID: 37898164 DOI: 10.1016/j.xphs.2023.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/21/2023] [Accepted: 10/21/2023] [Indexed: 10/30/2023]
Abstract
Over the past several decades, mathematical modeling has been applied to increasingly wider scopes of questions in drug development. Accordingly, the range of modeling tools has also been evolving, as showcased by contributions of Jusko and colleagues: from basic pharmacokinetics/pharmacodynamics (PK/PD) modeling to today's platform-based approach of quantitative systems pharmacology (QSP) modeling. Aimed at understanding the mechanism of action of investigational drugs, QSP models characterize systemic effects by incorporating information about cellular signaling networks, which is often represented by omics data. In this perspective, we share a few examples illustrating approaches for the integration of omics into mechanistic QSP modeling. We briefly overview how the evolution of PK/PD modeling into QSP has been accompanied by an increase in available data and the complexity of mathematical methods that integrate it. We discuss current gaps and challenges of integrating omics data into QSP models and propose several potential areas where integrated QSP and omics modeling may benefit drug development.
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Affiliation(s)
- Aydar Uatay
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Cambridge, United Kingdom.
| | - Louis Gall
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Cambridge, United Kingdom
| | - Linda Irons
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Waltham, MA, United States
| | - Shivendra G Tewari
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Gaithersburg, MD, United States
| | - Xu Sue Zhu
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Waltham, MA, United States
| | - Megan Gibbs
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Waltham, MA, United States
| | - Holly Kimko
- Clinical Pharmacology & Quantitative Pharmacology, R&D Biopharmaceuticals, Gaithersburg, MD, United States.
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7
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Niestrawska JA, Spronck B, Cavinato C, Humphrey JD. Tempol improves aortic mechanics in a mouse model of hypertension. J Biomech 2024; 162:111911. [PMID: 38150954 PMCID: PMC10896091 DOI: 10.1016/j.jbiomech.2023.111911] [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: 08/28/2023] [Revised: 11/22/2023] [Accepted: 12/14/2023] [Indexed: 12/29/2023]
Abstract
Hypertension-induced arterial remodeling is thought to be a response to increases in both mechanical stress and oxidative stress. The superoxide dismutase mimetic Tempol has been shown to reduce adverse aortic remodeling in multiple murine models of hypertension but in the absence of a detailed assessment of the biaxial biomechanics. We show that concurrent treatment with Tempol in a common mouse model of systemic hypertension results in modest reductions in both wall thickening and circumferential material stiffness that yet work together to achieve a significant reduction in calculated aortic pulse wave velocity. Reducing elevated values of pulse wave velocity engenders multiple benefits to cardiovascular function.
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Affiliation(s)
- Justyna A Niestrawska
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Bart Spronck
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands.
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Laboratoire de Mécanique et Génie Civile, Université Montpellier, Montpellier, France
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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8
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Schwarz EL, Pfaller MR, Szafron JM, Latorre M, Lindsey SE, Breuer CK, Humphrey JD, Marsden AL. A Fluid-Solid-Growth Solver for Cardiovascular Modeling. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2023; 417:116312. [PMID: 38044957 PMCID: PMC10691594 DOI: 10.1016/j.cma.2023.116312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
We implement full, three-dimensional constrained mixture theory for vascular growth and remodeling into a finite element fluid-structure interaction (FSI) solver. The resulting "fluid-solid-growth" (FSG) solver allows long term, patient-specific predictions of changing hemodynamics, vessel wall morphology, tissue composition, and material properties. This extension from short term (FSI) to long term (FSG) simulations increases clinical relevance by enabling mechanobioloigcally-dependent studies of disease progression in complex domains.
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Affiliation(s)
- Erica L Schwarz
- Department of Bioengineering, Stanford Univeristy, Stanford, CA 94306, USA
| | - Martin R Pfaller
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
| | - Jason M Szafron
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
| | - Marcos Latorre
- Center for Research and Innovation in Bioengineering, Universitat Politècnica de València, València 46022, Spain
| | - Stephanie E Lindsey
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
| | - Christopher K Breuer
- Department of Surgery, Nationwide Children's Hospital, Columbus, OH 43210, USA
- Center for Regenerative Medicine, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale Univeristy, New Haven, CT 06520, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford Univeristy, Stanford, CA 94306, USA
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
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9
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Vervenne T, Maes L, Van Hoof L, Rega F, Famaey N. Drivers of vascular growth and remodeling: A computational framework to promote benign adaptation in the Ross procedure. J Mech Behav Biomed Mater 2023; 148:106170. [PMID: 37852088 DOI: 10.1016/j.jmbbm.2023.106170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023]
Abstract
In the sixties, Dr Donald Ross designed a surgical solution for young patients with aortic valve disease by using the patients' own pulmonary valve. The Ross procedure is the only aortic valve replacement technique that can restore long-term survival and preserve quality of life. The main failure mode of the Ross procedure is wall dilatation, potentially leading to valve regurgitation and leakage. Dilatation occurs due to the inability of the pulmonary autograft to adapt to the sudden increase in loading when exposing to aortic pressures. Previous experimental data has shown that a permanent external support wrapped around the artery can prevent the acute dilatation of the arterial wall. However, the textile support leads to stress-shielding phenomena due to the loss of mechanical wall compliance. We present a pragmatic and modular computational framework of arterial growth and remodeling predicting the long-term outcomes of cardiovascular tissue adaptation, with and without textile wrapping. The model integrates mean, systolic and diastolic pressures and assumes the resulting wall stresses to drive the biological remodeling rules. Rather than a single mean pressure or stress deviation from the homeostatic state, we demonstrate that only pulsatile stresses can predict available experimental results. Therefore, we suggest that a biodegradable external support could induce benign remodeling in the Ross procedure. Indeed, a biodegradable textile wrapped around the autograft fulfills the trade-off between prevention of acute dilatation on the one hand and recovery of arterial wall compliance on the other hand. After further validation, the computational framework can set the basis for the development of an actual biodegradable external support for the Ross procedure with optimized polymer mechanical properties and degradation behavior.
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Affiliation(s)
- Thibault Vervenne
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300, Leuven, 3001, Belgium.
| | - Lauranne Maes
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300, Leuven, 3001, Belgium
| | - Lucas Van Hoof
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49, Leuven, 3000, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49, Leuven, 3000, Belgium
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300, Leuven, 3001, Belgium
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10
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van Asten JGM, Latorre M, Karakaya C, Baaijens FPT, Sahlgren CM, Ristori T, Humphrey JD, Loerakker S. A multiscale computational model of arterial growth and remodeling including Notch signaling. Biomech Model Mechanobiol 2023; 22:1569-1588. [PMID: 37024602 PMCID: PMC10511605 DOI: 10.1007/s10237-023-01697-3] [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: 12/14/2022] [Accepted: 01/31/2023] [Indexed: 04/08/2023]
Abstract
Blood vessels grow and remodel in response to mechanical stimuli. Many computational models capture this process phenomenologically, by assuming stress homeostasis, but this approach cannot unravel the underlying cellular mechanisms. Mechano-sensitive Notch signaling is well-known to be key in vascular development and homeostasis. Here, we present a multiscale framework coupling a constrained mixture model, capturing the mechanics and turnover of arterial constituents, to a cell-cell signaling model, describing Notch signaling dynamics among vascular smooth muscle cells (SMCs) as influenced by mechanical stimuli. Tissue turnover was regulated by both Notch activity, informed by in vitro data, and a phenomenological contribution, accounting for mechanisms other than Notch. This novel framework predicted changes in wall thickness and arterial composition in response to hypertension similar to previous in vivo data. The simulations suggested that Notch contributes to arterial growth in hypertension mainly by promoting SMC proliferation, while other mechanisms are needed to fully capture remodeling. The results also indicated that interventions to Notch, such as external Jagged ligands, can alter both the geometry and composition of hypertensive vessels, especially in the short term. Overall, our model enables a deeper analysis of the role of Notch and Notch interventions in arterial growth and remodeling and could be adopted to investigate therapeutic strategies and optimize vascular regeneration protocols.
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Affiliation(s)
- Jordy G M van Asten
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Marcos Latorre
- Center for Research and Innovation in Bioengineering, Universitat Politècnica de València, València, Spain
| | - Cansu Karakaya
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Frank P T Baaijens
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Cecilia M Sahlgren
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
- Faculty of Science and Engineering, Biosciences, Åbo Akademi, Turku, Finland
| | - Tommaso Ristori
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Sandra Loerakker
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.
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11
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Maes L, Vervenne T, Van Hoof L, Jones EAV, Rega F, Famaey N. Computational modeling reveals inflammation-driven dilatation of the pulmonary autograft in aortic position. Biomech Model Mechanobiol 2023; 22:1555-1568. [PMID: 36764979 DOI: 10.1007/s10237-023-01694-6] [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: 05/16/2022] [Accepted: 01/17/2023] [Indexed: 02/12/2023]
Abstract
The pulmonary autograft in the Ross procedure, where the aortic valve is replaced by the patient's own pulmonary valve, is prone to failure due to dilatation. This is likely caused by tissue degradation and maladaptation, triggered by the higher experienced mechanical loads in aortic position. In order to further grasp the causes of dilatation, this study presents a model for tissue growth and remodeling of the pulmonary autograft, using the homogenized constrained mixture theory and equations for immuno- and mechano-mediated mass turnover. The model outcomes, compared to experimental data from an animal model of the pulmonary autograft in aortic position, show that inflammation likely plays an important role in the mass turnover of the tissue constituents and therefore in the autograft dilatation over time. We show a better match and prediction of long-term outcomes assuming immuno-mediated mass turnover, and show that there is no linear correlation between the stress-state of the material and mass production. Therefore, not only mechanobiological homeostatic adaption should be taken into account in the development of growth and remodeling models for arterial tissue in similar applications, but also inflammatory processes.
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Affiliation(s)
- Lauranne Maes
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium.
| | - Thibault Vervenne
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium
| | - Lucas Van Hoof
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49 box 276, 3000, Leuven, Belgium
| | - Elizabeth A V Jones
- Centre for Molecular and Vascular Biology, KU Leuven, UZ Herestraat 49 box 911, 3000, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49 box 276, 3000, Leuven, Belgium
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium
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12
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Flanary SM, Jo S, Ravichandran R, Alejandro EU, Barocas VH. A computational bridge between traction force microscopy and tissue contraction. JOURNAL OF APPLIED PHYSICS 2023; 134:074901. [PMID: 37593660 PMCID: PMC10431945 DOI: 10.1063/5.0157507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/26/2023] [Indexed: 08/19/2023]
Abstract
Arterial wall active mechanics are driven by resident smooth muscle cells, which respond to biological, chemical, and mechanical stimuli and activate their cytoskeletal machinery to generate contractile stresses. The cellular mechanoresponse is sensitive to environmental perturbations, often leading to maladaptation and disease progression. When investigated at the single cell scale, however, these perturbations do not consistently result in phenotypes observed at the tissue scale. Here, a multiscale model is introduced that translates microscale contractility signaling into a macroscale, tissue-level response. The microscale framework incorporates a biochemical signaling network along with characterization of fiber networks that govern the anisotropic mechanics of vascular tissue. By incorporating both biochemical and mechanical components, the model is more flexible and more broadly applicable to physiological and pathological conditions. The model can be applied to both cell and tissue scale systems, allowing for the analysis of in vitro, traction force microscopy and ex vivo, isometric contraction experiments in parallel. When applied to aortic explant rings and isolated smooth muscle cells, the model predicts that active contractility is not a function of stretch at intermediate strain. The model also successfully predicts cell-scale and tissue-scale contractility and matches experimentally observed behaviors, including the hypercontractile phenotype caused by chronic hyperglycemia. The connection of the microscale framework to the macroscale through the multiscale model presents a framework that can translate the wealth of information already collected at the cell scale to tissue scale phenotypes, potentially easing the development of smooth muscle cell-targeting therapeutics.
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Affiliation(s)
- Shannon M. Flanary
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Rohit Ravichandran
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Victor H. Barocas
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
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13
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Figueroa M, Hall S, Mattia V, Mendoza A, Brown A, Xiong Y, Mukherjee R, Jones JA, Richardson W, Ruddy JM. Vascular smooth muscle cell mechanotransduction through serum and glucocorticoid inducible kinase-1 promotes interleukin-6 production and macrophage accumulation in murine hypertension. JVS Vasc Sci 2023; 4:100124. [PMID: 37920479 PMCID: PMC10618507 DOI: 10.1016/j.jvssci.2023.100124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 08/01/2023] [Indexed: 11/04/2023] Open
Abstract
Objective The objective of this investigation was to demonstrate that in vivo induction of hypertension (HTN) and in vitro cyclic stretch of aortic vascular smooth muscle cells (VSMCs) can cause serum and glucocorticoid-inducible kinase (SGK-1)-dependent production of cytokines to promote macrophage accumulation that may promote vascular pathology. Methods HTN was induced in C57Bl/6 mice with angiotensin II infusion (1.46 mg/kg/day × 21 days) with or without systemic infusion of EMD638683 (2.5 mg/kg/day × 21 days), a selective SGK-1 inhibitor. Systolic blood pressure was recorded. Abdominal aortas were harvested to quantify SGK-1 activity (pSGK-1/SGK-1) by immunoblot. Flow cytometry quantified the abundance of CD11b+/F480+ cells (macrophages). Plasma interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) was assessed by enzyme-linked immunosorbent assay. Aortic VSMCs from wild-type mice were subjected to 12% biaxial cyclic stretch (Stretch) for 3 or 12 hours with or without EMD638683 (10 μM) and with or without SGK-1 small interfering RNA with subsequent quantitative polymerase chain reaction for IL-6 and MCP-1 expression. IL-6 and MCP-1 in culture media were analyzed by enzyme-linked immunosorbent assay. Aortic VSMCs from SGK-1flox+/+ mice were transfected with Cre-Adenovirus to knockdown SGK-1 (SGK-1KD VSMCs) and underwent parallel tension experimentation. Computational modeling was used to simulate VSMC signaling. Statistical analysis included analysis of variance with significance at a P value of <.05. Results SGK-1 activity, abundance of CD11b+/F4-80+ cells, and plasma IL-6 were increased in the abdominal aorta of mice with HTN and significantly reduced by treatment with EMD638683. This outcome mirrored the increased abundance of IL-6 in media from Stretch C57Bl/6 VSMCs and attenuation of the effect with EMD638683 or SGK-1 small interfering RNA. C57Bl/6 VSMCs also responded to Stretch with increased MCP-1 expression and secretion into the culture media. Further supporting the integral role of mechanical signaling through SGK-1, target gene expression and cytokine secretion was unchanged in SGK-1KD VSMCs with Stretch, and computer modeling confirmed SGK-1 as an intersecting node of signaling owing to mechanical strain and angiotensin II. Conclusions Mechanical activation of SGK-1 in aortic VSMCs can promote inflammatory signaling and increased macrophage abundance, therefore this kinase warrants further exploration as a pharmacotherapeutic target to abrogate hypertensive vascular pathology.
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Affiliation(s)
- Mario Figueroa
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - SarahRose Hall
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Victoria Mattia
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Alex Mendoza
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Adam Brown
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
| | - Ying Xiong
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC
| | - Rupak Mukherjee
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC
| | - Jeffrey A. Jones
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC
- Ralph H. Johnson VA Medical Center, Charleston, SC
| | - William Richardson
- Department of Chemical Engineering, University of Arkansas, Fayetteville, AK
| | - Jean Marie Ruddy
- Division of Vascular Surgery, Medical University of South Carolina, Charleston, SC
- Ralph H. Johnson VA Medical Center, Charleston, SC
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14
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Irons L, Cavinato C, Humphrey JD. Persistent non-homeostatic remodeling of aortic collagen following a brief episode of hypertension: A computational study. J Mech Behav Biomed Mater 2023; 144:105966. [PMID: 37327590 PMCID: PMC10353492 DOI: 10.1016/j.jmbbm.2023.105966] [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: 03/11/2023] [Revised: 05/23/2023] [Accepted: 06/06/2023] [Indexed: 06/18/2023]
Abstract
The healthy adult aorta exhibits a remarkable homeostatic ability to respond to sustained changes in hemodynamic loads under many circumstances, but this mechanical homeostasis can be compromised or lost in natural aging and diverse pathological processes. Herein, we investigate persistent non-homeostatic changes in the composition and mechanical properties of the thoracic aorta in adult wild-type mice following 14 days of angiotensin II-induced hypertension. We employ a multiscale computational model of arterial growth and remodeling driven by mechanosensitive and angiotensin II-related cell signaling pathways. We find that experimentally observed findings can only be recapitulated computationally if the collagen deposited during the transient period of hypertension has altered properties (deposition stretch, fiber angle, crosslinking) compared with the collagen produced in the original homeostatic state. Some of these changes are predicted to persist for at least six months after blood pressure is restored to normal levels, consistent with the experimental findings.
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Affiliation(s)
- Linda Irons
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA.
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15
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Flanary SM, Barocas VH. A structural bio-chemo-mechanical model for vascular smooth muscle cell traction force microscopy. Biomech Model Mechanobiol 2023; 22:1221-1238. [PMID: 37004657 PMCID: PMC10603623 DOI: 10.1007/s10237-023-01713-6] [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: 11/15/2022] [Accepted: 03/13/2023] [Indexed: 04/04/2023]
Abstract
Altered vascular smooth muscle cell (VSMC) contractility is both a response to and a driver for impaired arterial function, and the leading experimental technique for quantifying VSMC contraction is traction force microscopy (TFM). TFM involves the complex interaction among several chemical, biological, and mechanical mechanisms, making it difficult to translate TFM results into tissue-scale behavior. Here, a computational model capturing each of the major aspects of the cell traction process is presented. The model incorporates four interacting components: a biochemical signaling network, individual actomyosin fiber bundle contraction, a cytoskeletal network of interconnected fibers, and elastic substrate displacement due to cytoskeletal force. The synthesis of these four components leads to a broad, flexible framework for describing TFM and linking biochemical and biomechanical phenomena on the single-cell level. The model recapitulated available data on VSMCs following biochemical, geometric, and mechanical perturbations. The structural bio-chemo-mechanical model offers a tool to interpret TFM data in new, more mechanistic ways, providing a framework for the evaluation of new biological hypotheses, interpolation of new data, and potential translation from single-cell experiments to multi-scale tissue models.
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Affiliation(s)
- Shannon M Flanary
- Department of Chemical Engineering & Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Victor H Barocas
- Department of Biomedical Engineering, University of Minnesota, Nils Hasselmo Hall, Room 7-115, 312 Church St SE, Minneapolis, MN, 55455, USA.
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16
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Schwarz EL, Pegolotti L, Pfaller MR, Marsden AL. Beyond CFD: Emerging methodologies for predictive simulation in cardiovascular health and disease. BIOPHYSICS REVIEWS 2023; 4:011301. [PMID: 36686891 PMCID: PMC9846834 DOI: 10.1063/5.0109400] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 12/12/2022] [Indexed: 01/15/2023]
Abstract
Physics-based computational models of the cardiovascular system are increasingly used to simulate hemodynamics, tissue mechanics, and physiology in evolving healthy and diseased states. While predictive models using computational fluid dynamics (CFD) originated primarily for use in surgical planning, their application now extends well beyond this purpose. In this review, we describe an increasingly wide range of modeling applications aimed at uncovering fundamental mechanisms of disease progression and development, performing model-guided design, and generating testable hypotheses to drive targeted experiments. Increasingly, models are incorporating multiple physical processes spanning a wide range of time and length scales in the heart and vasculature. With these expanded capabilities, clinical adoption of patient-specific modeling in congenital and acquired cardiovascular disease is also increasing, impacting clinical care and treatment decisions in complex congenital heart disease, coronary artery disease, vascular surgery, pulmonary artery disease, and medical device design. In support of these efforts, we discuss recent advances in modeling methodology, which are most impactful when driven by clinical needs. We describe pivotal recent developments in image processing, fluid-structure interaction, modeling under uncertainty, and reduced order modeling to enable simulations in clinically relevant timeframes. In all these areas, we argue that traditional CFD alone is insufficient to tackle increasingly complex clinical and biological problems across scales and systems. Rather, CFD should be coupled with appropriate multiscale biological, physical, and physiological models needed to produce comprehensive, impactful models of mechanobiological systems and complex clinical scenarios. With this perspective, we finally outline open problems and future challenges in the field.
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Affiliation(s)
- Erica L. Schwarz
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Luca Pegolotti
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Martin R. Pfaller
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Alison L. Marsden
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
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17
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Loerakker S, Humphrey JD. Computer Model-Driven Design in Cardiovascular Regenerative Medicine. Ann Biomed Eng 2023; 51:45-57. [PMID: 35974236 PMCID: PMC9832109 DOI: 10.1007/s10439-022-03037-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/20/2022] [Indexed: 01/28/2023]
Abstract
Continuing advances in genomics, molecular and cellular mechanobiology and immunobiology, including transcriptomics and proteomics, and biomechanics increasingly reveal the complexity underlying native tissue and organ structure and function. Identifying methods to repair, regenerate, or replace vital tissues and organs remains one of the greatest challenges of modern biomedical engineering, one that deserves our very best effort. Notwithstanding the continuing need for improving standard methods of investigation, including cell, organoid, and tissue culture, biomaterials development and fabrication, animal models, and clinical research, it is increasingly evident that modern computational methods should play increasingly greater roles in advancing the basic science, bioengineering, and clinical application of regenerative medicine. This brief review focuses on the development and application of computational models of tissue and organ mechanobiology and mechanics for purposes of designing tissue engineered constructs and understanding their development in vitro and in situ. Although the basic approaches are general, for illustrative purposes we describe two recent examples from cardiovascular medicine-tissue engineered heart valves (TEHVs) and tissue engineered vascular grafts (TEVGs)-to highlight current methods of approach as well as continuing needs.
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Affiliation(s)
- Sandra Loerakker
- Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Jay D Humphrey
- Department of Biomedical Engineering and Vascular Biology & Therapeutics Program, Yale University and Yale School of Medicine, New Haven, CT, USA.
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18
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Irons L, Estrada AC, Humphrey JD. Intracellular signaling control of mechanical homeostasis in the aorta. Biomech Model Mechanobiol 2022; 21:1339-1355. [PMID: 35867282 PMCID: PMC10547132 DOI: 10.1007/s10237-022-01593-2] [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: 02/03/2022] [Accepted: 05/10/2022] [Indexed: 11/27/2022]
Abstract
Mature arteries exhibit a preferred biomechanical state in health evidenced by a narrow range of intramural and wall shear stresses. When stresses are perturbed by changes in blood pressure or flow, homeostatic mechanisms tend to restore target values via altered contractility and/or cell and matrix turnover. In contrast, vascular disease associates with compromised homeostasis, hence we must understand mechanisms underlying mechanical homeostasis and its robustness. Here, we use a multiscale computational model wherein mechanosensitive intracellular signaling pathways drive arterial growth and remodeling. First, we identify an ensemble of cell-level parameterizations where tissue-level responses are well-regulated and adaptive to hemodynamic perturbations. The responsible mechanism is persistent multiscale negative feedback whereby mechanosensitive signaling drives mass turnover until homeostatic target stresses are reached. This demonstrates how robustness emerges despite inevitable cell and individual heterogeneity. Second, we investigate tissue-level effects of signaling node knockdowns (ATIR, ROCK, TGF[Formula: see text]RII, PDGFR, ERK1/2) and find general agreement with experimental reports of fault tolerance. Robustness against structural changes manifests via low engagement of the node under baseline stresses or compensatory multiscale feedback via upregulation of additional pathways. Third, we show how knockdowns affect collagen and smooth muscle turnover at baseline and with perturbed stresses. In several cases, basal production is not remarkably affected, but sensitivities to stress deviations, which influence feedback strength, are reduced. Such reductions can impair adaptive responses, consistent with previously reported aortic vulnerability despite grossly normal appearances. Reduced stress sensitivities thus form a candidate mechanism for how robustness is lost, enabling transitions from health towards disease.
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Affiliation(s)
- Linda Irons
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Ana C Estrada
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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19
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Gacek E, Mahutga RR, Barocas VH. Hybrid Discrete-Continuum Multiscale Model of Tissue Growth and Remodeling. Acta Biomater 2022; 163:7-24. [PMID: 36155097 DOI: 10.1016/j.actbio.2022.09.040] [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: 03/31/2022] [Revised: 09/11/2022] [Accepted: 09/15/2022] [Indexed: 11/26/2022]
Abstract
Tissue growth and remodeling (G&R) is often central to disease etiology and progression, so understanding G&R is essential for understanding disease and developing effective therapies. While the state-of-the-art in this regard is animal and cellular models, recent advances in computational tools offer another avenue to investigate G&R. A major challenge for computational models is bridging from the cellular scale (at which changes are actually occurring) to the macroscopic, geometric-scale (at which physiological consequences arise). Thus, many computational models simplify one scale or another in the name of computational tractability. In this work, we develop a discrete-continuum modeling scheme for analyzing G&R, in which we apply changes directly to the discrete cell and extracellular matrix (ECM) architecture and pass those changes up to a finite-element macroscale geometry. We demonstrate the use of the model in three case-study scenarios: the media of a thick-walled artery, and the media and adventitia of a thick-walled artery, and chronic dissection of an arterial wall. We analyze each case in terms of the new and insightful data that can be gathered from this technique, and we compare our results from this model to several others. STATEMENT OF SIGNIFICANCE: This work is significant in that it provides a framework for combining discrete, microstructural- and cellular-scale models to the growth and remodeling of large tissue structures (such as the aorta). It is a significant advance in that it couples the microscopic remodeling with an existing macroscopic finite element model, making it relatively easy to use for a wide range of conceptual models. It has the potential to improve understanding of many growth and remodeling processes, such as organ formation during development and aneurysm formation, growth, and rupture.
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Affiliation(s)
- Elizabeth Gacek
- Department of Biomedical Engineering, University of Minnesota - Twin Cities, Minneapolis, MN, 55455
| | - Ryan R Mahutga
- Department of Biomedical Engineering, University of Minnesota - Twin Cities, Minneapolis, MN, 55455
| | - Victor H Barocas
- Department of Biomedical Engineering, University of Minnesota - Twin Cities, Minneapolis, MN, 55455.
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20
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van Asten JGM, Ristori T, Nolan DR, Lally C, Baaijens FPT, Sahlgren CM, Loerakker S. Computational analysis of the role of mechanosensitive Notch signaling in arterial adaptation to hypertension. J Mech Behav Biomed Mater 2022; 133:105325. [PMID: 35839633 PMCID: PMC7613661 DOI: 10.1016/j.jmbbm.2022.105325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/03/2022] [Accepted: 06/18/2022] [Indexed: 11/29/2022]
Abstract
Arteries grow and remodel in response to mechanical stimuli. Hypertension, for example, results in arterial wall thickening. Cell-cell Notch signaling between vascular smooth muscle cells (VSMCs) is known to be involved in this process, but the underlying mechanisms are still unclear. Here, we investigated whether Notch mechanosensitivity to strain may regulate arterial thickening in hypertension. We developed a multiscale computational framework by coupling a finite element model of arterial mechanics, including residual stress, to an agent-based model of mechanosensitive Notch signaling, to predict VSMC phenotypes as an indicator of growth and remodeling. Our simulations revealed that the sensitivity of Notch to strain at mean blood pressure may be a key mediator of arterial thickening in hypertensive arteries. Further simulations showed that loss of residual stress can have synergistic effects with hypertension, and that changes in the expression of Notch receptors, but not Jagged ligands, may be used to control arterial growth and remodeling and to intensify or counteract hypertensive thickening. Overall, we identify Notch mechanosensitivity as a potential mediator of vascular adaptation, and we present a computational framework that can facilitate the testing of new therapeutic and regenerative strategies.
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Affiliation(s)
- Jordy G M van Asten
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Tommaso Ristori
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - David R Nolan
- School of Engineering and Trinity Centre for Biomedical Engineering, Trinity College Dublin, Dublin, Ireland
| | - Caitríona Lally
- School of Engineering and Trinity Centre for Biomedical Engineering, Trinity College Dublin, Dublin, Ireland
| | - Frank P T Baaijens
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Cecilia M Sahlgren
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands; Faculty of Science and Engineering, Biosciences, Åbo Akademi, Turku, Finland
| | - Sandra Loerakker
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands.
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21
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Guo Y, Mofrad MRK, Tepole AB. On modeling the multiscale mechanobiology of soft tissues: Challenges and progress. BIOPHYSICS REVIEWS 2022; 3:031303. [PMID: 38505274 PMCID: PMC10903412 DOI: 10.1063/5.0085025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 07/12/2022] [Indexed: 03/21/2024]
Abstract
Tissues grow and remodel in response to mechanical cues, extracellular and intracellular signals experienced through various biological events, from the developing embryo to disease and aging. The macroscale response of soft tissues is typically nonlinear, viscoelastic anisotropic, and often emerges from the hierarchical structure of tissues, primarily their biopolymer fiber networks at the microscale. The adaptation to mechanical cues is likewise a multiscale phenomenon. Cell mechanobiology, the ability of cells to transform mechanical inputs into chemical signaling inside the cell, and subsequent regulation of cellular behavior through intra- and inter-cellular signaling networks, is the key coupling at the microscale between the mechanical cues and the mechanical adaptation seen macroscopically. To fully understand mechanics of tissues in growth and remodeling as observed at the tissue level, multiscale models of tissue mechanobiology are essential. In this review, we summarize the state-of-the art modeling tools of soft tissues at both scales, the tissue level response, and the cell scale mechanobiology models. To help the interested reader become more familiar with these modeling frameworks, we also show representative examples. Our aim here is to bring together scientists from different disciplines and enable the future leap in multiscale modeling of tissue mechanobiology.
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Affiliation(s)
- Yifan Guo
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Mohammad R. K. Mofrad
- Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California 94720, USA
| | - Adrian Buganza Tepole
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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22
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Estrada AC, Irons L, Rego BV, Li G, Tellides G, Humphrey JD. Roles of mTOR in thoracic aortopathy understood by complex intracellular signaling interactions. PLoS Comput Biol 2021; 17:e1009683. [PMID: 34898595 PMCID: PMC8700007 DOI: 10.1371/journal.pcbi.1009683] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/23/2021] [Accepted: 11/26/2021] [Indexed: 02/01/2023] Open
Abstract
Thoracic aortopathy–aneurysm, dissection, and rupture–is increasingly responsible for significant morbidity and mortality. Advances in medical genetics and imaging have improved diagnosis and thus enabled earlier prophylactic surgical intervention in many cases. There remains a pressing need, however, to understand better the underlying molecular and cellular mechanisms with the hope of finding robust pharmacotherapies. Diverse studies in patients and mouse models of aortopathy have revealed critical changes in multiple smooth muscle cell signaling pathways that associate with disease, yet integrating information across studies and models has remained challenging. We present a new quantitative network model that includes many of the key smooth muscle cell signaling pathways and validate the model using a detailed data set that focuses on hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and its inhibition using rapamycin. We show that the model can be parameterized to capture the primary experimental findings both qualitatively and quantitatively. We further show that simulating a population of cells by varying receptor reaction weights leads to distinct proteomic clusters within the population, and that these clusters emerge due to a bistable switch driven by positive feedback in the PI3K/AKT/mTOR signaling pathway. Cell signaling drives changes across scales, from altered transcription at the single-cell level to tissue-level growth and remodeling. Studying complex interactions within cell signaling pathways can lead to a better understanding of the progression of disease. In particular, we are interested in how vascular cells can change their phenotype in a way that exacerbates aortopathy, namely, the development of aneurysms, dissections, and rupture. In this study we built a novel cell signaling network model of a vascular smooth muscle cell using archival data and used it to capture the effects of a genetic knock-out and subsequent pharmacologic rescue. We then used the model to simulate populations of smooth muscle cells and found that small perturbations to the strength of signaling can lead to distinct clusters of cells. With further analysis of the network substructures, we found that a positive feedback loop within the network was responsible for the distinct phenotypes we saw in our clusters of simulated cells. We believe that this work not only helps us to understand changes in smooth muscle cell phenotype but also opens the possibility to study other signaling perturbations associated with aortopathy.
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Affiliation(s)
- Ana C. Estrada
- Department of Biomedical Engineering, Yale University; New Haven, Connecticut, United States of America
| | - Linda Irons
- Department of Biomedical Engineering, Yale University; New Haven, Connecticut, United States of America
| | - Bruno V. Rego
- Department of Biomedical Engineering, Yale University; New Haven, Connecticut, United States of America
| | - Guangxin Li
- Department of Surgery, Yale School of Medicine; New Haven, Connecticut, United States of America
| | - George Tellides
- Department of Surgery, Yale School of Medicine; New Haven, Connecticut, United States of America
- Vascular Biology and Therapeutics Program, Yale School of Medicine; New Haven, Connecticut, United States of America
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University; New Haven, Connecticut, United States of America
- Vascular Biology and Therapeutics Program, Yale School of Medicine; New Haven, Connecticut, United States of America
- * E-mail:
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23
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Rego BV, Weiss D, Bersi MR, Humphrey JD. Uncertainty quantification in subject-specific estimation of local vessel mechanical properties. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3535. [PMID: 34605615 PMCID: PMC9019846 DOI: 10.1002/cnm.3535] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/26/2021] [Indexed: 05/08/2023]
Abstract
Quantitative estimation of local mechanical properties remains critically important in the ongoing effort to elucidate how blood vessels establish, maintain, or lose mechanical homeostasis. Recent advances based on panoramic digital image correlation (pDIC) have made high-fidelity 3D reconstructions of small-animal (e.g., murine) vessels possible when imaged in a variety of quasi-statically loaded configurations. While we have previously developed and validated inverse modeling approaches to translate pDIC-measured surface deformations into biomechanical metrics of interest, our workflow did not heretofore include a methodology to quantify uncertainties associated with local point estimates of mechanical properties. This limitation has compromised our ability to infer biomechanical properties on a subject-specific basis, such as whether stiffness differs significantly between multiple material locations on the same vessel or whether stiffness differs significantly between multiple vessels at a corresponding material location. In the present study, we have integrated a novel uncertainty quantification and propagation pipeline within our inverse modeling approach, relying on empirical and analytic Bayesian techniques. To demonstrate the approach, we present illustrative results for the ascending thoracic aorta from three mouse models, quantifying uncertainties in constitutive model parameters as well as circumferential and axial tangent stiffness. Our extended workflow not only allows parameter uncertainties to be systematically reported, but also facilitates both subject-specific and group-level statistical analyses of the mechanics of the vessel wall.
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Affiliation(s)
- Bruno V. Rego
- Department of Biomedical Engineering, School of Engineering & Applied Science, Yale University, New Haven, CT, USA
| | - Dar Weiss
- Department of Biomedical Engineering, School of Engineering & Applied Science, Yale University, New Haven, CT, USA
| | - Matthew R. Bersi
- Department of Mechanical Engineering & Materials Science, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jay D. Humphrey
- Department of Biomedical Engineering, School of Engineering & Applied Science, Yale University, New Haven, CT, USA
- Correspondence Jay D. Humphrey, Department of Biomedical Engineering, Malone Engineering Center, Yale University, New Haven, CT, USA.
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24
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Karakaya C, van Asten JGM, Ristori T, Sahlgren CM, Loerakker S. Mechano-regulated cell-cell signaling in the context of cardiovascular tissue engineering. Biomech Model Mechanobiol 2021; 21:5-54. [PMID: 34613528 PMCID: PMC8807458 DOI: 10.1007/s10237-021-01521-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 09/15/2021] [Indexed: 01/18/2023]
Abstract
Cardiovascular tissue engineering (CVTE) aims to create living tissues, with the ability to grow and remodel, as replacements for diseased blood vessels and heart valves. Despite promising results, the (long-term) functionality of these engineered tissues still needs improvement to reach broad clinical application. The functionality of native tissues is ensured by their specific mechanical properties directly arising from tissue organization. We therefore hypothesize that establishing a native-like tissue organization is vital to overcome the limitations of current CVTE approaches. To achieve this aim, a better understanding of the growth and remodeling (G&R) mechanisms of cardiovascular tissues is necessary. Cells are the main mediators of tissue G&R, and their behavior is strongly influenced by both mechanical stimuli and cell-cell signaling. An increasing number of signaling pathways has also been identified as mechanosensitive. As such, they may have a key underlying role in regulating the G&R of tissues in response to mechanical stimuli. A more detailed understanding of mechano-regulated cell-cell signaling may thus be crucial to advance CVTE, as it could inspire new methods to control tissue G&R and improve the organization and functionality of engineered tissues, thereby accelerating clinical translation. In this review, we discuss the organization and biomechanics of native cardiovascular tissues; recent CVTE studies emphasizing the obtained engineered tissue organization; and the interplay between mechanical stimuli, cell behavior, and cell-cell signaling. In addition, we review past contributions of computational models in understanding and predicting mechano-regulated tissue G&R and cell-cell signaling to highlight their potential role in future CVTE strategies.
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Affiliation(s)
- Cansu Karakaya
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Jordy G M van Asten
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Tommaso Ristori
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands.,Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Cecilia M Sahlgren
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands.,Faculty of Science and Engineering, Biosciences, Åbo Akademi, Turku, Finland
| | - Sandra Loerakker
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands. .,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands.
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25
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Abstract
Multiscale computational modeling aims to connect the complex networks of effects at different length and/or time scales. For example, these networks often include intracellular molecular signaling, crosstalk, and other interactions between neighboring cell populations, and higher levels of emergent phenomena across different regions of tissues and among collections of tissues or organs interacting with each other in the whole body. Recent applications of multiscale modeling across intracellular, cellular, and/or tissue levels are highlighted here. These models incorporated the roles of biochemical and biomechanical modulation in processes that are implicated in the mechanisms of several diseases including fibrosis, joint and bone diseases, respiratory infectious diseases, and cancers.
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26
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Humphrey JD. Constrained Mixture Models of Soft Tissue Growth and Remodeling - Twenty Years After. JOURNAL OF ELASTICITY 2021; 145:49-75. [PMID: 34483462 PMCID: PMC8415366 DOI: 10.1007/s10659-020-09809-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/29/2020] [Indexed: 05/06/2023]
Abstract
Soft biological tissues compromise diverse cell types and extracellular matrix constituents, each of which can possess individual natural configurations, material properties, and rates of turnover. For this reason, mixture-based models of growth (changes in mass) and remodeling (change in microstructure) are well-suited for studying tissue adaptations, disease progression, and responses to injury or clinical intervention. Such approaches also can be used to design improved tissue engineered constructs to repair, replace, or regenerate tissues. Focusing on blood vessels as archetypes of soft tissues, this paper reviews a constrained mixture theory introduced twenty years ago and explores its usage since by contrasting simulations of diverse vascular conditions. The discussion is framed within the concept of mechanical homeostasis, with consideration of solid-fluid interactions, inflammation, and cell signaling highlighting both past accomplishments and future opportunities as we seek to understand better the evolving composition, geometry, and material behaviors of soft tissues under complex conditions.
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Affiliation(s)
- J D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520 USA
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