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Whitehead B, Velazquez-Cruz R, Albowaidey A, Zhang N, Karelina K, Weil ZM. Mild Traumatic Brain Injury Induces Time- and Sex-Dependent Cerebrovascular Dysfunction and Stroke Vulnerability. J Neurotrauma 2023; 40:578-591. [PMID: 36322789 PMCID: PMC9986031 DOI: 10.1089/neu.2022.0335] [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] [Indexed: 11/06/2022] Open
Abstract
Mild traumatic brain injury (mTBI) produces subtle cerebrovascular impairments that persist over time and promote increased ischemic stroke vulnerability. We recently established a role for vascular impairments in exacerbating stroke outcomes 1 week after TBI, but there is a lack of research regarding long-term impacts of mTBI-induced vascular dysfunction, as well as a significant need to understand how mTBI promotes stroke vulnerability in both males and females. Here, we present data using a mild closed head TBI model and an experimental stroke occurring either 7 or 28 days later in both male and female mice. We report that mTBI induces larger stroke volumes 7 days after injury, however, this increased vulnerability to stroke persists out to 28 days in female but not male mice. Importantly, mTBI-induced changes in blood-brain barrier permeability, intravascular coagulation, angiogenic factors, total vascular area, and glial expression were differentially altered across time and by sex. Taken together, these data suggest that mTBI can result in persistent cerebrovascular dysfunction and increased susceptibility to worsened ischemic outcomes, although these dysfunctions occur differently in male and female mice.
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Affiliation(s)
- Bailey Whitehead
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Ruth Velazquez-Cruz
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Ali Albowaidey
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Ning Zhang
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Kate Karelina
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
| | - Zachary M. Weil
- Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
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2
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Converse MI, Monson KL. Biaxial softening of isolated cerebral arteries following axial overstretch. J Mech Behav Biomed Mater 2021; 118:104447. [PMID: 33725523 DOI: 10.1016/j.jmbbm.2021.104447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 11/26/2022]
Abstract
Arteries play a critical role in carrying essential nutrients and oxygen throughout the brain; however, vessels can become damaged in traumatic brain injury (TBI), putting neural tissue at risk. Even in the absence of hemorrhage, large deformations can disrupt both the physiological and mechanical behavior of the cerebral vessels. Our group recently reported the effect of vessel overstretch on axial mechanics; however, that work did not address possible changes in circumferential mechanics that are critical to the regulation of blood flow. In order to address this in the present work, ovine middle cerebral arteries were isolated and overstretched axially to 10, 20, or 40% beyond the in vivo configuration. Results showed a statistically significant decrease in circumferential stiffness and strain energy, as well as an increase in vessel diameter following 40% overstretch (p < 0.05). These passive changes would lead to a decrease in vascular resistance and likely play a role in previous reports of cellular dysfunction. We anticipate that our findings will both increase understanding of vessel softening phenomena and also promote improved modeling of cerebrovascular mechanics following head trauma.
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Affiliation(s)
- Matthew I Converse
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, 84112, United States
| | - Kenneth L Monson
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, 84112, United States; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, United States.
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3
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Knutsen AK, Gomez AD, Gangolli M, Wang WT, Chan D, Lu YC, Christoforou E, Prince JL, Bayly PV, Butman JA, Pham DL. In vivo estimates of axonal stretch and 3D brain deformation during mild head impact. BRAIN MULTIPHYSICS 2020; 1. [PMID: 33870238 DOI: 10.1016/j.brain.2020.100015] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The rapid deformation of brain tissue in response to head impact can lead to traumatic brain injury. In vivo measurements of brain deformation during non-injurious head impacts are necessary to understand the underlying mechanisms of traumatic brain injury and compare to computational models of brain biomechanics. Using tagged magnetic resonance imaging (MRI), we obtained measurements of three-dimensional strain tensors that resulted from a mild head impact after neck rotation or neck extension. Measurements of maximum principal strain (MPS) peaked shortly after impact, with maximal values of 0.019-0.053 that correlated strongly with peak angular velocity. Subject-specific patterns of MPS were spatially heterogeneous and consistent across subjects for the same motion, though regions of high deformation differed between motions. The largest MPS values were seen in the cortical gray matter and cerebral white matter for neck rotation and the brainstem and cerebellum for neck extension. Axonal fiber strain (Ef) was estimated by combining the strain tensor with diffusion tensor imaging data. As with MPS, patterns of Ef varied spatially within subjects, were similar across subjects within each motion, and showed group differences between motions. Values were highest and most strongly correlated with peak angular velocity in the corpus callosum for neck rotation and in the brainstem for neck extension. The different patterns of brain deformation between head motions highlight potential areas of greater risk of injury between motions at higher loading conditions. Additionally, these experimental measurements can be directly compared to predictions of generic or subject-specific computational models of traumatic brain injury.
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Affiliation(s)
- Andrew K Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Arnold D Gomez
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mihika Gangolli
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Wen-Tung Wang
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Deva Chan
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Yuan-Chiao Lu
- Center for the Developing Brain, Children's National Hospital, Washington, D.C., USA
| | | | - Jerry L Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Philip V Bayly
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, Missouri, USA
| | - John A Butman
- Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Dzung L Pham
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
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4
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Nauman EA, Talavage TM, Auerbach PS. Mitigating the Consequences of Subconcussive Head Injuries. Annu Rev Biomed Eng 2020; 22:387-407. [PMID: 32348156 DOI: 10.1146/annurev-bioeng-091219-053447] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Subconcussive head injury represents a pathophysiology that spans the expertise of both clinical neurology and biomechanical engineering. From both viewpoints, the terms injury and damage, presented without qualifiers, are synonymously taken to mean a tissue alteration that may be recoverable. For clinicians, concussion is evolving from a purely clinical diagnosis to one that requires objective measurement, to be achieved by biomedical engineers. Subconcussive injury is defined as subclinical pathophysiology in which underlying cellular- or tissue-level damage (here, to the brain) is not severe enough to present readily observable symptoms. Our concern is not whether an individual has a (clinically diagnosed) concussion, but rather, how much accumulative damage an individual can tolerate before they will experience long-term deficit(s) in neurological health. This concern leads us to look for the history of damage-inducing events, while evaluating multiple approaches for avoiding injury through reduction or prevention of the associated mechanically induced damage.
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Affiliation(s)
- Eric A Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA; .,School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.,Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana 47907, USA
| | - Thomas M Talavage
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA; .,School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Paul S Auerbach
- Department of Emergency Medicine, Stanford University, Palo Alto, California 94304, USA
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Bailey ZS, Cardiff K, Yang X, Gilsdorf J, Shear D, Rasmussen TE, Leung LY. The Effects of Balloon Occlusion of the Aorta on Cerebral Blood Flow, Intracranial Pressure, and Brain Tissue Oxygen Tension in a Rodent Model of Penetrating Ballistic-Like Brain Injury. Front Neurol 2019; 10:1309. [PMID: 31920932 PMCID: PMC6930175 DOI: 10.3389/fneur.2019.01309] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/26/2019] [Indexed: 12/14/2022] Open
Abstract
Trauma is among the leading causes of death in the United States. Technological advancements have led to the development of resuscitative endovascular balloon occlusion of the aorta (REBOA) which offers a pre-hospital option to non-compressible hemorrhage control. Due to the prevalence of concomitant traumatic brain injury (TBI), an understanding of the effects of REBOA on cerebral physiology is critical. To further this understanding, we employed a rat model of penetrating ballistic-like brain injury (PBBI). PBBI produced an injury pattern within the right frontal cortex and striatum that replicates the pathology from a penetrating ballistic round. Aortic occlusion was initiated 30 min post-PBBI and maintained continuously (cAO) or intermittently (iAO) for 30 min. Continuous measurements of mean arterial pressure (MAP), intracranial pressure (ICP), cerebral blood flow (CBF), and brain tissue oxygen tension (PbtO2) were recorded during, and for 60 min following occlusion. PBBI increased ICP and decreased CBF and PbtO2. The arterial balloon catheter effectively occluded the descending aorta which augmented MAP in the carotid artery. Despite this, CBF levels were not changed by aortic occlusion. iAO caused sustained adverse effects to ICP and PbtO2 while cAO demonstrated no adverse effects on either. Temporary increases in PbtO2 were observed during occlusion, along with restoration of sham levels of ICP for the remainder of the recordings. These results suggest that iAO may lead to prolonged cerebral hypertension following PBBI. Following cAO, ICP, and PbtO2 levels were temporarily improved. This information warrants further investigation using TBI-polytrauma model and provides foundational knowledge surrounding the non-hemorrhage applications of REBOA including neurogenic shock and stroke.
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Affiliation(s)
- Zachary S Bailey
- Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Katherine Cardiff
- Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Xiaofang Yang
- Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Janice Gilsdorf
- Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Deborah Shear
- Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Todd E Rasmussen
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Lai Yee Leung
- Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States.,Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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6
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Chan DD, Knutsen AK, Lu YC, Yang SH, Magrath E, Wang WT, Bayly PV, Butman JA, Pham DL. Statistical Characterization of Human Brain Deformation During Mild Angular Acceleration Measured In Vivo by Tagged Magnetic Resonance Imaging. J Biomech Eng 2019; 140:2681445. [PMID: 30029236 DOI: 10.1115/1.4040230] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Indexed: 01/17/2023]
Abstract
Understanding of in vivo brain biomechanical behavior is critical in the study of traumatic brain injury (TBI) mechanisms and prevention. Using tagged magnetic resonance imaging, we measured spatiotemporal brain deformations in 34 healthy human volunteers under mild angular accelerations of the head. Two-dimensional (2D) Lagrangian strains were examined throughout the brain in each subject. Strain metrics peaked shortly after contact with a padded stop, corresponding to the inertial response of the brain after head deceleration. Maximum shear strain of at least 3% was experienced at peak deformation by an area fraction (median±standard error) of 23.5±1.8% of cortical gray matter, 15.9±1.4% of white matter, and 4.0±1.5% of deep gray matter. Cortical gray matter strains were greater in the temporal cortex on the side of the initial contact with the padded stop and also in the contralateral temporal, frontal, and parietal cortex. These tissue-level deformations from a population of healthy volunteers provide the first in vivo measurements of full-volume brain deformation in response to known kinematics. Although strains differed in different tissue type and cortical lobes, no significant differences between male and female head accelerations or strain metrics were found. These cumulative results highlight important kinematic features of the brain's mechanical response and can be used to facilitate the evaluation of computational simulations of TBI.
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Affiliation(s)
- Deva D Chan
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Andrew K Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20892
| | - Yuan-Chiao Lu
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20892
| | - Sarah H Yang
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20892
| | - Elizabeth Magrath
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20892
| | - Wen-Tung Wang
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20892
| | - Philip V Bayly
- Professor Department of Mechanical Engineering and Materials Science, Washington University at St. Louis, St. Louis, MO 63130
| | - John A Butman
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892
| | - Dzung L Pham
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, , Bethesda, MD 20892-1182 e-mail:
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7
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Monson KL, Converse MI, Manley GT. Cerebral blood vessel damage in traumatic brain injury. Clin Biomech (Bristol, Avon) 2019; 64:98-113. [PMID: 29478776 DOI: 10.1016/j.clinbiomech.2018.02.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/12/2018] [Accepted: 02/13/2018] [Indexed: 02/07/2023]
Abstract
Traumatic brain injury is a devastating cause of death and disability. Although injury of brain tissue is of primary interest in head trauma, nearly all significant cases include damage of the cerebral blood vessels. Because vessels are critical to the maintenance of the healthy brain, any injury or dysfunction of the vasculature puts neural tissue at risk. It is well known that these vessels commonly tear and bleed as an immediate consequence of traumatic brain injury. It follows that other vessels experience deformations that are significant though not severe enough to produce bleeding. Recent data show that such subfailure deformations damage the microstructure of the cerebral vessels, altering both their structure and function. Little is known about the prognosis of these injured vessels and their potential contribution to disease development. The objective of this review is to describe the current state of knowledge on the mechanics of cerebral vessels during head trauma and how they respond to the applied loads. Further research on these topics will clarify the role of blood vessels in the progression of traumatic brain injury and is expected to provide insight into improved strategies for treatment of the disease.
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Affiliation(s)
- Kenneth L Monson
- Department of Mechanical Engineering, University of Utah, USA; Department of Bioengineering, University of Utah, USA.
| | | | - Geoffrey T Manley
- Department of Neurological Surgery, University of California, San Francisco, USA
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8
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David Bell E, Converse M, Mao H, Unnikrishnan G, Reifman J, Monson KL. Material Properties of Rat Middle Cerebral Arteries at High Strain Rates. J Biomech Eng 2018; 140:2675985. [DOI: 10.1115/1.4039625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Indexed: 11/08/2022]
Abstract
Traumatic brain injury (TBI), resulting from either impact- or nonimpact blast-related mechanisms, is a devastating cause of death and disability. The cerebral blood vessels, which provide critical support for brain tissue in both health and disease, are commonly injured in TBI. However, little is known about how vessels respond to traumatic loading, particularly at rates relevant to blast. To better understand vessel responses to trauma, the objective of this project was to characterize the high-rate response of passive cerebral arteries. Rat middle cerebral arteries (MCAs) were isolated and subjected to high-rate deformation in the axial direction. Vessels were perfused at physiological pressures and stretched to failure at strain rates ranging from approximately 100 to 1300 s−1. Although both in vivo stiffness and failure stress increased significantly with strain rate, failure stretch did not depend on rate.
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Affiliation(s)
- E. David Bell
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112
| | - Matthew Converse
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112
| | - Haojie Mao
- Telemedicine and Advanced Technology Research Center, Department of Defense Biotechnology High Performance Computing Software Applications Institute, U.S. Army Medical Research and Materiel Command, Frederick, MD 21702
| | - Ginu Unnikrishnan
- Telemedicine and Advanced Technology Research Center, Department of Defense Biotechnology High Performance Computing Software Applications Institute, U.S. Army Medical Research and Materiel Command, Frederick, MD 21702
| | - Jaques Reifman
- Telemedicine and Advanced Technology Research Center, Department of Defense Biotechnology High Performance Computing Software Applications Institute, U.S. Army Medical Research and Materiel Command, Frederick, MD 21702
| | - Kenneth L. Monson
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112; Department of Mechanical Engineering, University of Utah, 1495 E. 100 S., MEK 1550, Salt Lake City, UT 84112 e-mail:
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9
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Converse MI, Walther RG, Ingram JT, Li Y, Yu SM, Monson KL. Detection and characterization of molecular-level collagen damage in overstretched cerebral arteries. Acta Biomater 2018; 67:307-318. [PMID: 29225149 PMCID: PMC5794621 DOI: 10.1016/j.actbio.2017.11.052] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 11/21/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022]
Abstract
It is well established that overstretch of arteries alters their mechanics and compromises their function. However, the underlying structural mechanisms behind these changes are poorly understood. Utilizing a recently developed collagen hybridizing peptide (CHP), we demonstrate that a single mechanical overstretch of an artery produces molecular-level unfolding of collagen. In addition, imaging and quantification of CHP binding revealed that overstretch produces damage (unfolding) among fibers aligned with the direction of loading, that damage increases with overstretch severity, and that the onset of this damage is closely associated with tissue yielding. These findings held true for both axial and circumferential loading directions. Our results are the first to identify stretch-induced molecular damage to collagen in blood vessels. Furthermore, our approach is advantageous over existing methods of collagen damage detection as it is non-destructive, readily visualized, and objectively quantified. This work opens the door to revealing additional structure-function relationships in arteries. We anticipate that this approach can be used to better understand arterial damage in clinically relevant settings such as angioplasty and vascular trauma. Furthermore, CHP can be a tool for the development of microstructurally-based constitutive models and experimentally validated computational models of arterial damage and damage propagation across physical scales. STATEMENT OF SIGNIFICANCE Arteries play a critical role by carrying oxygen and essential nutrients throughout the body. However, trauma to the head and neck, as well as surgical interventions, can overstretch arteries and alter their mechanics. In order to better understand the cause of these changes, we employ a novel collagen hybridizing peptide (CHP) to study collagen damage in overstretched arteries. Our approach is unique in that we go beyond the fiber- and fibril-level and characterize molecular-level disruption. In addition, we image and quantify fluorescently-labeled CHP to reveal a new structure-property relationship in arterial damage. We anticipate that our approach can be used to better understand arterial damage in clinically relevant settings such as angioplasty and vascular trauma.
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Affiliation(s)
- Matthew I Converse
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, United States
| | - Raymond G Walther
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, United States
| | - Justin T Ingram
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, United States
| | - Yang Li
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, United States
| | - S Michael Yu
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, United States; Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, United States
| | - Kenneth L Monson
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, United States; Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, United States.
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10
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Arterial wall remodeling under sustained axial twisting in rats. J Biomech 2017; 60:124-133. [PMID: 28693818 DOI: 10.1016/j.jbiomech.2017.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 06/13/2017] [Accepted: 06/14/2017] [Indexed: 01/03/2023]
Abstract
Blood vessels often experience torsion along their axes and it is essential to understand their biological responses and wall remodeling under torsion. To this end, a rat model was developed to investigate the arterial wall remodeling under sustained axial twisting in vivo. Rat carotid arteries were twisted at 180° along the longitudinal axis through a surgical procedure and maintained for different durations up to 4weeks. The wall remodeling in these twisted arteries was examined using histology, immunohistochemistry and fluorescent microscopy. Our data showed that arteries remodeled under twisting in a time-dependent manner during the 4weeks post-surgery. Cell proliferation, MMP-2 and MMP-9 expressions, medial wall thickness and lumen diameter increased while collagen to elastin ratio decreased. The size and number of internal elastic lamina fenestrae increased with elongated shapes, while the endothelial cells elongated and aligned towards the blood flow direction gradually. These results demonstrated that sustained axial twisting results in artery remodeling in vivo. The rat carotid artery twisting model is an effective in vivo model for studying arterial wall remodeling under long-term torsion. These results enrich our understanding of vascular biology and arterial wall remodeling under mechanical stresses.
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