1
|
Pasta S, Catalano C, Crascì F, Scuoppo R. A custom-built planar biaxial system for soft tissue material testing. HARDWAREX 2023; 16:e00475. [PMID: 37771321 PMCID: PMC10523007 DOI: 10.1016/j.ohx.2023.e00475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/13/2023] [Accepted: 09/18/2023] [Indexed: 09/30/2023]
Abstract
Accurate material characterization of soft tissues is crucial for understanding the physiopathology of cardiovascular diseases. However, commercial biaxial testing systems are expensive, prompting the need for affordable custom solutions. This study aimed to develop a low-cost custom biaxial system capable of accurately characterizing the mechanical behavior of soft tissues. The biaxial system was constructed using 3D printing technology and non-captive linear actuators for precise displacement control. A real-time marker tracking system was implemented to estimate dis-placements without the need for costly hardware. The system's performance was evaluated through tests on a calibration spring and frozen porcine aorta samples. The linear actuators demonstrated excellent response to user position input after motor tuning, showing no discrepancies between commands and actual positions. The experimental testing of the calibration spring showed good agreement with the analytical solution, validating the system's ability to accurately test materials. Testing on porcine aorta samples revealed stress-strain responses consistent with existing literature, accounting for potential variations due to tissue preservation and regional material property heterogeneity. Overall, this custom biaxial system demonstrates promising performance in accurately assessing the mechanical behavior of soft tissues, providing researchers with a valuable tool for cardiovascular disease research and tissue engineering applications.
Collapse
Affiliation(s)
- Salvatore Pasta
- Department of Engineering, Viale delle Scienze, Università degli Studi di Palermo, Palermo, Italy
- Department of Research, IRCCS-ISMETT, Palermo, Italy
| | - Chiara Catalano
- Department of Engineering, Viale delle Scienze, Università degli Studi di Palermo, Palermo, Italy
| | - Fabrizio Crascì
- Department of Engineering, Viale delle Scienze, Università degli Studi di Palermo, Palermo, Italy
| | - Roberta Scuoppo
- Department of Engineering, Viale delle Scienze, Università degli Studi di Palermo, Palermo, Italy
| |
Collapse
|
2
|
Ghadie NM, Labrosse MR, St-Pierre JP. Glycosaminoglycans modulate compressive stiffness and circumferential residual stress in the porcine thoracic aorta. Acta Biomater 2023; 170:556-566. [PMID: 37683966 DOI: 10.1016/j.actbio.2023.08.061] [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: 05/01/2023] [Revised: 08/26/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023]
Abstract
The mechanical properties of the aorta are influenced by the extracellular matrix, a network mainly comprised of fibers and glycosaminoglycans (GAG). In this work, we demonstrate that GAG contribute to the opening angle (a marker of circumferential residual stresses) in intact and glycated aortic tissue. Enzymatic GAG depletion was associated with a decrease in the opening angle, by approximately 25% (p = 0.009) in the ascending (AS) region, 32% (p = 0.003) in the aortic arch (AR), and 42% (p = 0.001) in the lower descending thoracic (LDT) region. A similar effect of GAG depletion on aortic ring opening angle was also observed in previously glycated tissues. Using indentation testing, we found that the radial compressive stiffness significantly increased in the AS region following GAG depletion, compared to fresh (p = 0.006) and control samples (p = 0.021), and that the compressive properties are heterogeneous along the aortic tree. A small loss of water content was also detected after GAG depletion, which was most prominent under hypotonic conditions. Finally, the AS region was also associated with a significant loss of compressive deformation (circumferential stretch that is < 1) in the inner layer of the aorta following GAG depletion, suggesting that GAG interact with ECM fibers in their effect on aortic mechanics. The importance of this work lies in its identification of the role of GAG in modulating the mechanical properties of the aorta, namely the circumferential residual stresses and the radial compressive stiffness, as well as contributing to the swelling state and the level of circumferential prestretch in the tissue. STATEMENT OF SIGNIFICANCE: The mechanical properties of the aorta are influenced by the composition and organization of its extracellular matrix (ECM) and are highly relevant to medical conditions affecting the structural integrity of the aorta. The extent of contribution of glycosaminoglycans (GAG), a relatively minor ECM component, to the mechanical properties of the aorta, remains poorly characterized. This works shows that GAG contribute on average 30% to the opening angle (an indicator of circumferential residual stresses) of porcine aortas, and that GAG-depletion is associated with an increased radial compressive stiffness of the aorta. GAG-depletion was also associated with a loss of water content and compressive deformation in the inner layers of the aortic wall providing insight into potential mechanisms for their biomechanical role.
Collapse
Affiliation(s)
- Noor M Ghadie
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N6N5, Canada
| | - Michel R Labrosse
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N6N5, Canada; Department of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, ON K1Y4W7, Canada
| | - Jean-Philippe St-Pierre
- Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, ON K1N6N5, Canada.
| |
Collapse
|
3
|
Guo T, Zou X, Sundar S, Jia X, Dhong C. In situ measurement of viscoelastic properties of cellular monolayers via graphene strain sensing of elastohydrodynamic phenomena. LAB ON A CHIP 2023; 23:4067-4078. [PMID: 37610268 PMCID: PMC10498944 DOI: 10.1039/d3lc00457k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/10/2023] [Indexed: 08/24/2023]
Abstract
Recent advances recognize that the viscoelastic properties of epithelial structures play important roles in biology and disease modeling. However, accessing the viscoelastic properties of multicellular structures in mechanistic or drug-screening applications has challenges in repeatability, accuracy, and practical implementation. Here, we present a microfluidic platform that leverages elastohydrodynamic phenomena, sensed by strain sensors made from graphene decorated with palladium nanoislands, to measure the viscoelasticity of cellular monolayers in situ, without using chemical labels or specialized equipment. We demonstrate platform utility with two systems: cell dissociation following trypsinization, where viscoelastic properties change over minutes, and epithelial-to-mesenchymal transition, where changes occur over days. These cellular events could only be resolved with our platform's higher resolution: viscoelastic relaxation time constants of λ = 14.5 ± 0.4 s-1 for intact epithelial monolayers, compared to λ = 13.4 ± 15.0 s-1 in other platforms, which represents a 30-fold improvement. By rapidly assessing combined contributions from cell stiffness and intercellular interactions, we anticipate that the platform will hasten the translation of new mechanical biomarkers.
Collapse
Affiliation(s)
- Tianzheng Guo
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, USA.
| | - Xiaoyu Zou
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, USA.
| | - Shalini Sundar
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716, USA
| | - Xinqiao Jia
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, USA.
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716, USA
| | - Charles Dhong
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, USA.
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716, USA
| |
Collapse
|
4
|
Swiatlowska P, Sit B, Feng Z, Marhuenda E, Xanthis I, Zingaro S, Ward M, Zhou X, Xiao Q, Shanahan C, Jones GE, Yu CH, Iskratsch T. Pressure and stiffness sensing together regulate vascular smooth muscle cell phenotype switching. SCIENCE ADVANCES 2022; 8:eabm3471. [PMID: 35427166 PMCID: PMC9012473 DOI: 10.1126/sciadv.abm3471] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Vascular smooth muscle cells (VSMCs) play a central role in the progression of atherosclerosis, where they switch from a contractile to a synthetic phenotype. Because of their role as risk factors for atherosclerosis, we sought here to systematically study the impact of matrix stiffness and (hemodynamic) pressure on VSMCs. Thereby, we find that pressure and stiffness individually affect the VSMC phenotype. However, only the combination of hypertensive pressure and matrix compliance, and as such mechanical stimuli that are prevalent during atherosclerosis, leads to a full phenotypic switch including the formation of matrix-degrading podosomes. We further analyze the molecular mechanism in stiffness and pressure sensing and identify a regulation through different but overlapping pathways culminating in the regulation of the actin cytoskeleton through cofilin. Together, our data show how different pathological mechanical signals combined but through distinct pathways accelerate a phenotypic switch that will ultimately contribute to atherosclerotic disease progression.
Collapse
Affiliation(s)
- Pamela Swiatlowska
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Brian Sit
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, UK
- School of Biomedical Sciences, Hong Kong University, Hong Kong, Hong Kong
| | - Zhen Feng
- School of Biomedical Sciences, Hong Kong University, Hong Kong, Hong Kong
| | - Emilie Marhuenda
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Ioannis Xanthis
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Simona Zingaro
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, UK
| | - Matthew Ward
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Xinmiao Zhou
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Qingzhong Xiao
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Cathy Shanahan
- School of Cardiovascular Medicine and Sciences, King’s College London, London, UK
| | - Gareth E. Jones
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, UK
| | - Cheng-han Yu
- School of Biomedical Sciences, Hong Kong University, Hong Kong, Hong Kong
| | - Thomas Iskratsch
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, UK
| |
Collapse
|
5
|
Hossack M, Fisher R, Torella F, Madine J, Field M, Akhtar R. Micromechanical and Ultrastructural Properties of Abdominal Aortic Aneurysms. Artery Res 2022. [DOI: 10.1007/s44200-022-00011-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
AbstractAbdominal aortic aneurysms are a common condition of uncertain pathogenesis that can rupture if left untreated. Current recommended thresholds for planned repair are empirical and based entirely on diameter. It has been observed that some aneurysms rupture before reaching the threshold for repair whilst other larger aneurysms do not rupture. It is likely that geometry is not the only factor influencing rupture risk. Biomechanical indices aiming to improve and personalise rupture risk prediction require, amongst other things, knowledge of the material properties of the tissue and realistic constitutive models. These depend on the composition and organisation of the vessel wall which has been shown to undergo drastic changes with aneurysmal degeneration, with loss of elastin, smooth muscle cells, and an accumulation of isotropically arranged collagen. Most aneurysms are lined with intraluminal thrombus, which has an uncertain effect on the underlying vessel wall, with some authors demonstrating a reduction in wall stress and others a reduction in wall strength. The majority of studies investigating biomechanical properties of ex vivo abdominal aortic aneurysm tissues have used low-resolution techniques, such as tensile testing, able to measure the global material properties at the macroscale. High-resolution engineering techniques such as nanoindentation and atomic force microscopy have been modified for use in soft biological tissues and applied to vascular tissues with promising results. These techniques have the potential to advance the understanding and improve the management of abdominal aortic aneurysmal disease.
Collapse
|
6
|
Wurm F, Pinggera GM, Pham T, Bechtold T. Investigation on the Behavior of κ -Carrageenan Hydrogels for Compressive Intra-Vessel Disintegration. Macromol Biosci 2020; 21:e2000348. [PMID: 33274844 DOI: 10.1002/mabi.202000348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/05/2020] [Indexed: 11/07/2022]
Abstract
Gel disintegration via compression is a possible approach for the reversal of the occlusion of male vasa deferentia (VD) by hydrogels. κ -carrageenan (KC) hydrogels can be used for such an application. To determine the required forces for in-vessel compressive disintegration, a gel-tube model, preparing KC gels in different tubes, is studied. These gels are of alternating biopolymer (1-3% by mass) and potassium (100-300 mM) concentration. Gel-filled tubes are uniaxially compressed at two different compression speeds (1 and 0.3 mm s-1 ). Breakage compression strains are cross studied by shear breaking gel measurements using dynamic mechanical analysis. The measurements showed good agreement. Gel structure disintegration occurred below (62 ± 8) % strain. During compression, three stages of gel disintegration are present. Gel-tube wall detachment, gel rupture, and gel expulsion. The force required for gel disintegration and tube deformation can be added arithmetically. From the modulus of a human aortae model, it is estimated that average human pinch forces are insufficient to disintegrate 2% and 3% by mass KC hydrogels in VD by massage. The compressive disintegration would require a compression device while evading tissue damage.
Collapse
Affiliation(s)
- Florian Wurm
- Research Institute of Textile Chemistry/Physics, University of Innsbruck, Hoechsterstrasse 73, Dornbirn, 6850, Austria
| | - Germar-Michael Pinggera
- Department of Urology, Medical University Innsbruck, Anichstrasse 35 A, Innsbruck, 6020, Austria
| | - Tung Pham
- Research Institute of Textile Chemistry/Physics, University of Innsbruck, Hoechsterstrasse 73, Dornbirn, 6850, Austria
| | - Thomas Bechtold
- Research Institute of Textile Chemistry/Physics, University of Innsbruck, Hoechsterstrasse 73, Dornbirn, 6850, Austria
| |
Collapse
|
7
|
Iendaltseva O, Orlova VV, Mummery CL, Danen EHJ, Schmidt T. Fibronectin Patches as Anchoring Points for Force Sensing and Transmission in Human Induced Pluripotent Stem Cell-Derived Pericytes. Stem Cell Reports 2020; 14:1107-1122. [PMID: 32470326 PMCID: PMC7355144 DOI: 10.1016/j.stemcr.2020.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 12/24/2022] Open
Abstract
Pericytes (PCs) have been reported to contribute to the mechanoregulation of the capillary diameter and blood flow in health and disease. How this is realized remains poorly understood. We designed several models representing basement membrane (BM) in between PCs and endothelial cells (ECs). These models captured a unique protein organization with micron-sized FN patches surrounded by laminin (LM) and allowed to obtain quantitative information on PC morphology and contractility. Using human induced pluripotent stem cell-derived PCs, we could address mechanical aspects of mid-capillary PC behavior in vitro. Our results showed that PCs strongly prefer FN patches over LM for adhesion formation, have an optimal stiffness for spreading in the range of EC rigidity, and react in a non-canonical way with increased traction forces and reduced spreading on other stiffness then the optimal. Our approach opens possibilities to further study PC force regulation under well-controlled conditions.
Collapse
Affiliation(s)
- Olga Iendaltseva
- Physics of Life Processes, Leiden Institute of Physics, Leiden University, Einsteinweg 55, Leiden, South Holland 2333 CC, the Netherlands; Division of Drug Discovery and Safety, Leiden Academic Center for Drug Research, Leiden University, Einsteinweg 55, Leiden, South Holland 2333 CC, the Netherlands
| | - Valeria V Orlova
- Department of Anatomy and Embryology, Leiden University Medical Center (LUMC), Leiden, South Holland, the Netherlands
| | - Christine L Mummery
- Department of Anatomy and Embryology, Leiden University Medical Center (LUMC), Leiden, South Holland, the Netherlands
| | - Erik H J Danen
- Division of Drug Discovery and Safety, Leiden Academic Center for Drug Research, Leiden University, Einsteinweg 55, Leiden, South Holland 2333 CC, the Netherlands.
| | - Thomas Schmidt
- Physics of Life Processes, Leiden Institute of Physics, Leiden University, Einsteinweg 55, Leiden, South Holland 2333 CC, the Netherlands.
| |
Collapse
|
8
|
Chim YH, Davies HA, Mason D, Nawaytou O, Field M, Madine J, Akhtar R. Bicuspid valve aortopathy is associated with distinct patterns of matrix degradation. J Thorac Cardiovasc Surg 2019; 160:e239-e257. [PMID: 31679706 PMCID: PMC7674632 DOI: 10.1016/j.jtcvs.2019.08.094] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/16/2019] [Accepted: 08/21/2019] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To explore the micromechanical, biochemical, and microstructural differences between bicuspid aortic valve aneurysm (BAV-A) and tricuspid aortic valve idiopathic degenerative aneurysm (DA), compared with normal aorta. METHODS Aortic tissue was obtained from patients undergoing aneurysmal repair surgery (BAV-A; n = 15 and DA; n = 15). Control tissue was obtained from aortic punch biopsies during coronary artery bypass graft surgery (n = 9). Nanoindentation was used to determine the elastic modulus on the medial layer. Glycosaminoglycan, collagen, and elastin levels were measured using biochemical assays. Verhoeff Van Gieson-stained cross-sections were imaged for elastin microstructural quantification. RESULTS The elastic modulus was more than 20% greater for BAV-A relative to control and DA (signifying a loss of compliance). No significance difference between control and DA were observed. Collagen levels for BAV-A (36.9 ± 7.4 μg/mg) and DA (49.9 ± 10.9 μg/mg) were greater compared with the control (30.2 ± 13.1 μg/mg). Glycosaminoglycan and elastin levels were not significant between the groups. Elastin segments were uniform throughout the control. Aneurysmal tissues had less elastin segments close to the intima and adventitia layers. Both BAV-A and DA had elastin segments compacted in the media; however, elastin segments were highly fragmented in DA. CONCLUSIONS BAV-A has a greater loss of aortic wall compliance relative to DA and the control. Although elastin levels were equal for all groups, spatial distribution of elastin provided a unique profile of matrix degradation for BAV-A. Elastin compaction within the media of BAV-A may have resulted from the altered hemodynamic pressure against the wall, which could explain for the stiffness of the tissue.
Collapse
Affiliation(s)
- Ya Hua Chim
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - Hannah A Davies
- Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom; Liverpool Centre for Cardiovascular Sciences, University of Liverpool, Liverpool, United Kingdom
| | - David Mason
- Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Omar Nawaytou
- Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
| | - Mark Field
- Liverpool Centre for Cardiovascular Sciences, University of Liverpool, Liverpool, United Kingdom; Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
| | - Jillian Madine
- Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom; Liverpool Centre for Cardiovascular Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Riaz Akhtar
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, United Kingdom; Liverpool Centre for Cardiovascular Sciences, University of Liverpool, Liverpool, United Kingdom.
| |
Collapse
|
9
|
Meekel JP, Mattei G, Costache VS, Balm R, Blankensteijn JD, Yeung KK. A multilayer micromechanical elastic modulus measuring method in ex vivo human aneurysmal abdominal aortas. Acta Biomater 2019; 96:345-353. [PMID: 31306785 DOI: 10.1016/j.actbio.2019.07.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 06/23/2019] [Accepted: 07/11/2019] [Indexed: 02/07/2023]
Abstract
Abdominal aortic aneurysms (AAA) are common and potentially life-threatening aortic dilatations, due to the effect of hemodynamic changes on the aortic wall. Previous research has shown a potential pathophysiological role for increased macroscopic aneurysmal wall stiffness; however, not investigating micromechanical stiffness. We aimed to compile a new protocol to examine micromechanical live aortic stiffness (elastic moduli), correlated to histological findings with quantitative immunofluorescence (QIF). Live AAA biopsies (n = 7) and non-dilated aortas (controls; n = 3) were sectioned. Local elastic moduli of aortic intima, media and adventitia were analysed in the direction towards the lumen and vice versa with nanoindentation. Smooth muscle cells (SMC), collagen and fibroblasts were examined using QIF. Nanoindentation of AAA vs. controls demonstrated a 4-fold decrease in elastic moduli (p = 0.022) for layers combined and a 26-fold decrease (p = 0.017) for media-to-intima direction. QIF of AAA vs. controls revealed a 4-, 3- and 6-fold decrease of SMC, collagen and fibroblasts, respectively (p = 0.036). Correlations were found between bidirectional intima and media measurements (ρ = 0.661, p = 0.038) and all QIF analyses (ρ = 0.857-0.905, p = 0.002-0.007). We present a novel protocol to analyse microscopic elastic moduli in live aortic tissues using nanoindentation. Hence, our preliminary findings of decreased elastic moduli and altered wall composition warrant further microscopic stiffness investigation to potentially clarify AAA pathophysiology and to explore potential treatment by wall strengthening. STATEMENT OF SIGNIFICANCE: Although extensive research on the pathophysiology of dilated abdominal aortas (aneurysms) has been performed, the exact underlying pathways are still largely unclear. Previously, the macroscopic stiffness of the pathologic and healthy aortic wall has been studied. This study however, for the first time, studied the microscopic stiffness changes in live tissue of dilated and non-dilated abdominal aortas. This new protocol provides a device to analyse the alterations on cellular level within their microenvironment, whereas previous studies studied the aorta as a whole. Outcomes of these measurements might help to better understand the underlying origin of the incidence and progression of aneurysms and other aortic diseases.
Collapse
Affiliation(s)
- Jorn P Meekel
- Department of Vascular Surgery, Amsterdam University Medical Centers, Location VU Medical Center, Amsterdam, The Netherlands; Department of Physiology, Amsterdam University Medical Centers, Location VU Medical Center, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Giorgio Mattei
- Optics11 B.V., Amsterdam, The Netherlands; Biophotonics & Medical Imaging and LaserLaB, VU University Amsterdam, Amsterdam, The Netherlands; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Victor S Costache
- Department of Cardiovascular Surgery, Polisano Medlife Hospital, University "L. Blaga" Sibiu, Sibiu, Romania
| | - Ron Balm
- Department of Vascular Surgery, Amsterdam University Medical Centers, Location Amsterdam Medical Center, Amsterdam, the Netherlands
| | - Jan D Blankensteijn
- Department of Vascular Surgery, Amsterdam University Medical Centers, Location VU Medical Center, Amsterdam, The Netherlands
| | - Kak K Yeung
- Department of Vascular Surgery, Amsterdam University Medical Centers, Location VU Medical Center, Amsterdam, The Netherlands; Department of Physiology, Amsterdam University Medical Centers, Location VU Medical Center, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.
| |
Collapse
|
10
|
Sit B, Gutmann D, Iskratsch T. Costameres, dense plaques and podosomes: the cell matrix adhesions in cardiovascular mechanosensing. J Muscle Res Cell Motil 2019; 40:197-209. [PMID: 31214894 PMCID: PMC6726830 DOI: 10.1007/s10974-019-09529-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/15/2019] [Indexed: 12/12/2022]
Abstract
The stiffness of the cardiovascular environment changes during ageing and in disease and contributes to disease incidence and progression. For instance, increased arterial stiffness can lead to atherosclerosis, while stiffening of the heart due to fibrosis can increase the chances of heart failure. Cells can sense the stiffness of the extracellular matrix through integrin adhesions and other mechanosensitive structures and in response to this initiate mechanosignalling pathways that ultimately change the cellular behaviour. Over the past decades, interest in mechanobiology has steadily increased and with this also our understanding of the molecular basis of mechanosensing and transduction. However, much of our knowledge about the mechanisms is derived from studies investigating focal adhesions in non-muscle cells, which are distinct in several regards from the cell-matrix adhesions in cardiomyocytes (costameres) or vascular smooth muscle cells (dense plaques or podosomes). Therefore, we will look here first at the evidence for mechanical sensing in the cardiovascular system, before comparing the different cytoskeletal arrangements and adhesion sites in cardiomyocytes and vascular smooth muscle cells and what is known about mechanical sensing through the various structures.
Collapse
Affiliation(s)
- Brian Sit
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, London, UK
| | - Daniel Gutmann
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, London, UK
| | - Thomas Iskratsch
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, London, UK.
| |
Collapse
|
11
|
Leng X, Zhou B, Deng X, Davis L, Sutton MA, Shazly T, Lessner SM. Determination of Viscoelastic Properties of human Carotid Atherosclerotic Plaque by Inverse Boundary Value Analysis. IOP CONFERENCE SERIES. MATERIALS SCIENCE AND ENGINEERING 2018; 381. [PMID: 31156719 PMCID: PMC6544144 DOI: 10.1088/1757-899x/381/1/012171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study, we assessed the mechanical response of samples from human atherosclerotic diseased media and fibrous cap via uniaxial tensile testing. Results show a pronounced hysteresis phenomenon caused by viscoelasticity during the loading-unloading process. An inverse analysis method with finite element modeling was employed to identify the material parameter values for a viscoelastic anisotropic (VA) constitutive model through matching simulation predictions of load-displacement curves with experimental measurements. The identified material parameter values can be used in simulation studies of diseased human carotid arteries, including investigations of inflation processes associated with stenting or angioplasty.
Collapse
Affiliation(s)
- Xiaochang Leng
- Institute of Engineering Mechanics, Nanchang University, Jiangxi, 330031, People's Republic of China
| | - Boran Zhou
- Department of Radiology, Mayo Clinic, Rochester, MN 55905
| | - Xiaomin Deng
- College of Engineering and Computing, Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208
| | - Lindsey Davis
- College of Engineering and Computing, Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208
| | - Michael A Sutton
- College of Engineering and Computing, Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208.,College of Engineering and Computing, Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208
| | - Tarek Shazly
- College of Engineering and Computing, Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208.,College of Engineering and Computing, Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208
| | - Susan M Lessner
- College of Engineering and Computing, Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208.,School of Medicine, Department of Cell Biology & Anatomy, University of South Carolina, Columbia, SC 29208
| |
Collapse
|
12
|
|
13
|
López-Guimet J, Andilla J, Loza-Alvarez P, Egea G. High-Resolution Morphological Approach to Analyse Elastic Laminae Injuries of the Ascending Aorta in a Murine Model of Marfan Syndrome. Sci Rep 2017; 7:1505. [PMID: 28473723 PMCID: PMC5431420 DOI: 10.1038/s41598-017-01620-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 04/03/2017] [Indexed: 12/04/2022] Open
Abstract
In Marfan syndrome, the tunica media is disrupted, which leads to the formation of ascending aortic aneurysms. Marfan aortic samples are histologically characterized by the fragmentation of elastic laminae. However, conventional histological techniques using transverse sections provide limited information about the precise location, progression and 3D extension of the microstructural changes that occur in each lamina. We implemented a method using multiphoton excitation fluorescence microscopy and computational image processing, which provides high-resolution en-face images of segmented individual laminae from unstained whole aortic samples. We showed that internal elastic laminae and successive 2nd laminae are injured to a different extent in murine Marfan aortae; in particular, the density and size of fenestrae changed. Moreover, microstructural injuries were concentrated in the aortic proximal and convex anatomical regions. Other parameters such as the waviness and thickness of each lamina remained unaltered. In conclusion, the method reported here is a useful, unique tool for en-face laminae microstructure assessment that can obtain quantitative three-dimensional information about vascular tissue. The application of this method to murine Marfan aortae clearly shows that the microstructural damage in elastic laminae is not equal throughout the thickness of the tunica media and in the different anatomical regions of the ascending aorta.
Collapse
Affiliation(s)
- Júlia López-Guimet
- Departament de Biomedicina, Facultat de Medicina i Ciencies de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Jordi Andilla
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels, Barcelona, Spain
| | - Pablo Loza-Alvarez
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels, Barcelona, Spain
| | - Gustavo Egea
- Departament de Biomedicina, Facultat de Medicina i Ciencies de la Salut, Universitat de Barcelona, Barcelona, Spain. .,Institut de Recerca Biomèdica August Pi i Sunyer (IDIBAPS), Barcelona, Spain. .,Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Barcelona, Spain.
| |
Collapse
|
14
|
Askari F, Shafieian M, Solouk A, Hashemi A. A comparison of the material properties of natural and synthetic vascular walls. J Mech Behav Biomed Mater 2017; 71:209-215. [PMID: 28347955 DOI: 10.1016/j.jmbbm.2017.03.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/12/2017] [Accepted: 03/22/2017] [Indexed: 10/19/2022]
Abstract
Characterization of the mechanical properties of native and synthetic vascular grafts is an essential task in the process of designing novel vascular constructs. The aim in this study was to compare the mechanical behavior of ovine left Subclavian artery with that of POSS-PCU (a commercial biomaterial which is currently under clinical investigation. ClinicalTrials.gov Identifier: NCT02301312). We used Delfino's strain energy potential within the framework of quasilinear viscoelasticity theory to capture the viscoelastic response of the considered materials. The material parameters of the quasilinear viscoelastic constitutive equation were determined through a combination of experimental and computational method. First, a uniaxial tensile testing device was used to perform a series of stress relaxation tests on ring samples. Then, the derived quasilinear viscoelastic models were implemented into finite element system. With the aid of mechanical experimentation and finite element simulation, the material parameters were obtained, modified and used for comparison of the mechanical properties of vascular walls. The results showed that the stiffness and the long term viscoelastic parameters of POSS-PCU may lead to different stress responses of the vascular walls. These two factors can be improved by modifications in manufacturing parameters of the synthetic vessel.
Collapse
Affiliation(s)
- Forough Askari
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Ave, Tehran, Iran
| | - Mehdi Shafieian
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Ave, Tehran, Iran.
| | - Atefeh Solouk
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Ave, Tehran, Iran
| | - Ata Hashemi
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Ave, Tehran, Iran
| |
Collapse
|
15
|
Kermani G, Hemmasizadeh A, Assari S, Autieri M, Darvish K. Investigation of inhomogeneous and anisotropic material behavior of porcine thoracic aorta using nano-indentation tests. J Mech Behav Biomed Mater 2016; 69:50-56. [PMID: 28040607 DOI: 10.1016/j.jmbbm.2016.12.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/19/2016] [Accepted: 12/23/2016] [Indexed: 10/20/2022]
Abstract
This study investigates the inhomogeneity and anisotropy of porcine descending thoracic aorta in three dimensions using a custom-made nano-indentation technique and a quasi-linear viscoelastic modeling approach. The indentation tests were conducted in axial, circumferential, and radial orientations with about 100 μm spatial resolution. The ratio of the elastic moduli obtained in different orientations was used to quantify the tissue local anisotropy. The distal sections were generally stiffer than the proximal ones in both axial and circumferential indentations. Four distinct layers were identified across the thickness with significantly different mechanical properties. The stiffness of the medial quadrant was significantly lower than all other quadrants in axial indentation. The anisotropic behavior of the tissue was more pronounced in the lateral quadrant of the distal sections. The results of this study can be used to better understand the mechanisms of aorta deformation and improve the spatial accuracy of computational models of aorta.
Collapse
Affiliation(s)
- Golriz Kermani
- Department of Mechanical Engineering, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122, United States
| | - Ali Hemmasizadeh
- Department of Mechanical Engineering, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122, United States
| | - Soroush Assari
- Department of Mechanical Engineering, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122, United States
| | - Michael Autieri
- Department of Physiology, School of Medicine, Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, United States
| | - Kurosh Darvish
- Department of Mechanical Engineering, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122, United States.
| |
Collapse
|
16
|
Laksari K, Shahmirzadi D, Acosta CJ, Konofagou E. Energy-based constitutive modelling of local material properties of canine aortas. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160365. [PMID: 27703701 PMCID: PMC5043320 DOI: 10.1098/rsos.160365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/24/2016] [Indexed: 05/05/2023]
Abstract
This study aims at determining the in vitro anisotropic mechanical behaviour of canine aortic tissue. We specifically focused on spatial variations of these properties along the axis of the vessel. We performed uniaxial stretch tests on canine aortic samples in both circumferential and longitudinal directions, as well as histological examinations to derive the tissue's fibre orientations. We subsequently characterized a constitutive model that incorporates both phenomenological and structural elements to account for macroscopic and microstructural behaviour of the tissue. We showed the two fibre families were oriented at similar angles with respect to the aorta's axis. We also found significant changes in mechanical behaviour of the tissue as a function of axial position from proximal to distal direction: the fibres become more aligned with the aortic axis from 46° to 30°. Also, the linear shear modulus of media decreased as we moved distally along the aortic axis from 139 to 64 kPa. These changes derived from the parameters in the nonlinear constitutive model agreed well with the changes in tissue structure. In addition, we showed that isotropic contribution, carried by elastic lamellae, to the total stress induced in the tissue decreases at higher stretch ratios, whereas anisotropic stress, carried by collagen fibres, increases. The constitutive models can be readily used to design computational models of tissue deformation during physiological loading cycles. The findings of this study extend the understanding of local mechanical properties that could lead to region-specific diagnostics and treatment of arterial diseases.
Collapse
Affiliation(s)
- Kaveh Laksari
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Author for correspondence: Kaveh Laksari e-mail:
| | - Danial Shahmirzadi
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, USA
| | - Camilo J. Acosta
- Ultrasound and Elasticity Imaging Lab (UEIL), Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Elisa Konofagou
- Ultrasound and Elasticity Imaging Lab (UEIL), Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Department of Radiology, Columbia University, New York, NY, USA
| |
Collapse
|
17
|
Frequency-modulated atomic force microscopy localises viscoelastic remodelling in the ageing sheep aorta. J Mech Behav Biomed Mater 2016; 64:10-7. [PMID: 27479890 PMCID: PMC5020410 DOI: 10.1016/j.jmbbm.2016.07.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 07/08/2016] [Accepted: 07/14/2016] [Indexed: 12/23/2022]
Abstract
Age-related aortic stiffening is associated with cardiovascular diseases such as heart failure. The mechanical functions of the main structural components of the aorta, such as collagen and elastin, are determined in part by their organisation at the micrometer length scale. With age and disease both components undergo aberrant remodelling, hence, there is a need for accurate characterisation of the biomechanical properties at this length scale. In this study we used a frequency-modulated atomic force microscopy (FM-AFM) technique on a model of ageing in female sheep aorta (young: ~18 months, old: >8 years) to measure the micromechanical properties of the medial layer of the ascending aorta. The novelty of our FM-AFM method, operated at 30 kHz, is that it is non-contact and can be performed on a conventional AFM using the ׳cantilever tune’ mode, with a spatial (areal) resolution of around 1.6 μm2. We found significant changes in the elastic and viscoelastic properties within the medial lamellar unit (elastic lamellae and adjacent inter-lamellar space) with age. In particular, there was an increase in elastic modulus (Young; geometric mean (geometric SD)=42.9 (2.26) kPa, Old=113.9 (2.57) kPa, P<0.0001), G′ and G″ (storage and loss modulus respectively) (Young; G′=14.3 (2.26) kPa, Old G′=38.0 (2.57) kPa, P<0.0001; Young; G″=14.5 (2.56) kPa, Old G″=32.8 (2.52) kPa, P<0.0001). The trends observed in the elastic properties with FM-AFM matched those we have previously found using scanning acoustic microscopy (SAM). The utility of the FM-AFM method is that it does not require custom AFM hardware and can be used to simultaneously determine the elastic and viscoelastic behaviour of a biological sample.
Collapse
|
18
|
Kohn JC, Lampi MC, Reinhart-King CA. Age-related vascular stiffening: causes and consequences. Front Genet 2015; 6:112. [PMID: 25926844 PMCID: PMC4396535 DOI: 10.3389/fgene.2015.00112] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/03/2015] [Indexed: 01/18/2023] Open
Abstract
Arterial stiffening occurs with age and is closely associated with the progression of cardiovascular disease. Stiffening is most often studied at the level of the whole vessel because increased stiffness of the large arteries can impose increased strain on the heart leading to heart failure. Interestingly, however, recent evidence suggests that the impact of increased vessel stiffening extends beyond the tissue scale and can also have deleterious microscale effects on cellular function. Altered extracellular matrix (ECM) architecture has been recognized as a key component of the pre-atherogenic state. Here, the underlying causes of age-related vessel stiffening are discussed, focusing on age-related crosslinking of the ECM proteins as well as through increased matrix deposition. Methods to measure vessel stiffening at both the macro- and microscale are described, spanning from the pulse wave velocity measurements performed clinically to microscale measurements performed largely in research laboratories. Additionally, recent work investigating how arterial stiffness and the changes in the ECM associated with stiffening contributed to endothelial dysfunction will be reviewed. We will highlight how changes in ECM protein composition contribute to atherosclerosis in the vessel wall. Lastly, we will discuss very recent work that demonstrates endothelial cells (ECs) are mechano-sensitive to arterial stiffening, where changes in stiffness can directly impact EC health. Overall, recent studies suggest that stiffening is an important clinical target not only because of potential deleterious effects on the heart but also because it promotes cellular level dysfunction in the vessel wall, contributing to a pathological atherosclerotic state.
Collapse
Affiliation(s)
- Julie C Kohn
- Department of Biomedical Engineering, Cornell University Ithaca, NY, USA
| | - Marsha C Lampi
- Department of Biomedical Engineering, Cornell University Ithaca, NY, USA
| | | |
Collapse
|
19
|
Hemmasizadeh A, Tsamis A, Cheheltani R, Assari S, D'Amore A, Autieri M, Kiani MF, Pleshko N, Wagner WR, Watkins SC, Vorp D, Darvish K. Correlations between transmural mechanical and morphological properties in porcine thoracic descending aorta. J Mech Behav Biomed Mater 2015; 47:12-20. [PMID: 25837340 DOI: 10.1016/j.jmbbm.2015.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/27/2015] [Accepted: 03/10/2015] [Indexed: 02/02/2023]
Abstract
Determination of correlations between transmural mechanical and morphological properties of aorta would provide a quantitative baseline for assessment of preventive and therapeutic strategies for aortic injuries and diseases. A multimodal and multidisciplinary approach was adopted to characterize the transmural morphological properties of descending porcine aorta. Histology and multi-photon microscopy were used for describing the media layer micro-architecture in the circumferential-radial plane, and Fourier Transform infrared imaging spectroscopy was utilized for determining structural protein, and total protein content. The distributions of these quantified properties across the media thickness were characterized and their relationship with the mechanical properties from a previous study was determined. Our findings indicate that there is an increasing trend in the instantaneous Young׳s modulus (E), elastic lamella density (ELD), structural protein (SPR), total protein (TPR), and elastin and collagen circumferential percentage (ECP and CCP) from the inner towards the outer layers. Two regions with equal thickness (inner and outer halves) were determined with significantly different morphological and material properties. The results of this study represent a substantial step toward anatomical characterization of the aortic wall building blocks and establishment of a foundation for quantifying the role of microstructural components on the functionality of aorta.
Collapse
Affiliation(s)
- Ali Hemmasizadeh
- Departments of Mechanical Engineering, Temple University, Philadelphia, USA
| | - Alkiviadis Tsamis
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rabee Cheheltani
- Departments of Mechanical Engineering, Temple University, Philadelphia, USA
| | - Soroush Assari
- Departments of Mechanical Engineering, Temple University, Philadelphia, USA
| | - Antonio D'Amore
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Autieri
- Departments of Physiology, Temple University, Philadelphia, USA
| | - Mohammad F Kiani
- Departments of Mechanical Engineering, Temple University, Philadelphia, USA; Departments of Bioengineering, Temple University, Philadelphia, USA
| | - Nancy Pleshko
- Departments of Bioengineering, Temple University, Philadelphia, USA
| | - William R Wagner
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Simon C Watkins
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - David Vorp
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kurosh Darvish
- Departments of Mechanical Engineering, Temple University, Philadelphia, USA; Departments of Bioengineering, Temple University, Philadelphia, USA.
| |
Collapse
|
20
|
Avanzini A, Battini D, Bagozzi L, Bisleri G. Biomechanical evaluation of ascending aortic aneurysms. BIOMED RESEARCH INTERNATIONAL 2014; 2014:820385. [PMID: 24991568 PMCID: PMC4065659 DOI: 10.1155/2014/820385] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/21/2014] [Indexed: 11/27/2022]
Abstract
The biomechanical properties of ascending aortic aneurysms were investigated only in the last decade in a limited number of studies. Indeed, in recent years, there has been a growing interest in this field in order to identify new predictive parameters of risk of dissection, which may have clinical relevance. The researches performed so far have been conducted according to the methods used in the study of abdominal aortic aneurysms. In most cases, uniaxial or biaxial tensile tests were used, while in a smaller number of studies other methods, such as opening angle, bulge inflation, and inflation-extension tests, were used. However, parameters and protocols of these tests are at present very heterogeneous in the studies reported in the literature, and, therefore, the results are not comparable and are sometimes conflicting. The purpose of this review then thence to provide a comprehensive analysis of the experimental methodology for determination of biomechanical properties in the specific field of aneurysms of the ascending aorta to allow for better comparison and understanding of the results.
Collapse
Affiliation(s)
- Andrea Avanzini
- Department of Industrial and Mechanical Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy
| | - Davide Battini
- Department of Industrial and Mechanical Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy
| | - Lorenzo Bagozzi
- Division of Cardiac Surgery, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
| | - Gianluigi Bisleri
- Division of Cardiac Surgery, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
| |
Collapse
|
21
|
Akhtar R. In vitro characterisation of arterial stiffening: From the macro- to the nano-scale. Artery Res 2014. [DOI: 10.1016/j.artres.2014.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
|
22
|
Chen H, Slipchenko MN, Liu Y, Zhao X, Cheng JX, Lanir Y, Kassab GS. Biaxial deformation of collagen and elastin fibers in coronary adventitia. J Appl Physiol (1985) 2013; 115:1683-93. [PMID: 24092692 DOI: 10.1152/japplphysiol.00601.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The microstructural deformation-mechanical loading relation of the blood vessel wall is essential for understanding the overall mechanical behavior of vascular tissue in health and disease. We employed simultaneous mechanical loading-imaging to quantify in situ deformation of individual collagen and elastin fibers on unstained fresh porcine coronary adventitia under a combination of vessel inflation and axial extension loading. Specifically, the specimens were imaged under biaxial loads to study microscopic deformation-loading behavior of fibers in conjunction with morphometric measurements at the zero-stress state. Collagen fibers largely orientate in the longitudinal direction, while elastin fibers have major orientation parallel to collagen, but with additional orientation angles in each sublayer of the adventitia. With an increase of biaxial load, collagen fibers were uniformly stretched to the loading direction, while elastin fibers gradually formed a network in sublayers, which strongly depended on the initial arrangement. The waviness of collagen decreased more rapidly at a circumferential stretch ratio of λθ = 1.0 than at λθ = 1.5, while most collagen became straightened at λθ = 1.8. These microscopic deformations imply that the longitudinally stiffer adventitia is a direct result of initial fiber alignment, and the overall mechanical behavior of the tissue is highly dependent on the corresponding microscopic deformation of fibers. The microstructural deformation-loading relation will serve as a foundation for micromechanical models of the vessel wall.
Collapse
Affiliation(s)
- Huan Chen
- Department of Biomedical Engineering, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | | | | | | | | | | | | |
Collapse
|