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Epstein JA, Ramon GZ. In-situ measurement of the internal compaction of a soft material caused by permeation flow. J Colloid Interface Sci 2024; 673:883-892. [PMID: 38908287 DOI: 10.1016/j.jcis.2024.06.095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/09/2024] [Accepted: 06/11/2024] [Indexed: 06/24/2024]
Abstract
HYPOTHESIS The compaction of hydrogel films under permeation flow can be measured, in-situ, by tracking the internal displacements of their structure, thereby revealing the internal deformation profile. Additionally, monitoring the permeation flow rate and applied pressure over time enables determination of variations in the hydrogel's permeability due to flow-induced compaction. Hydrogels are soft porous materials capable of containing high amounts of water within their polymeric matrix. Flow-induced internal deformation can modify the hydrogel's permeability and selectivity, which are important attributes in separation processes, both industrial (e.g., membrane-based water purification) and natural (mucous filters in suspension feeders and intestinal lining) systems. Measuring the flow-induced compaction in thin hydrogels films can reveal the interplay between flow and permeability. However, the micro-scale internal compaction remains uncharted for due to experimental challenges. EXPERIMENTS A technique is demonstrated for analyzing the compaction and stratification of permeable soft materials, in-situ, created by a pressure-driven permeation flow. To this end, the internal deformations within a soft material layer are calculated, based on tracking the positions of fluorescent micro-tracers that are embedded within the soft material. We showcase the capabilities of this technique by examining a hundred-micron-thick calcium-alginate cake deposited on a nanofiltration membrane, emphasizing the achieved micro-scale resolution of the local compaction measurements. FINDINGS The results highlight the possibility to examine thin hydrogel films and their internal deformation produced by flow-induced stresses when varying the flow conditions. The method enables the simultaneous calculation of the soft material's permeance, as the pressure-driven flow conditions are continuously monitored. In summary, the proposed method provides a powerful tool for characterizing the behaviour of permeable soft materials under permeation conditions, with potential applications in engineering, biophysics and material science.
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Affiliation(s)
- José A Epstein
- Department of Civil & Environmental Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Guy Z Ramon
- Department of Civil & Environmental Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel; Department of Chemical Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel.
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Karimi A, Razaghi R, D'costa SD, Torbati S, Ebrahimi S, Rahmati SM, Kelley MJ, Acott TS, Gong H. Implementing new computational methods for the study of JCT and SC inner wall basement membrane biomechanics and hydrodynamics. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 243:107909. [PMID: 37976613 PMCID: PMC10840991 DOI: 10.1016/j.cmpb.2023.107909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/28/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023]
Abstract
PURPOSE The conventional aqueous outflow pathway, which includes the trabecular meshwork (TM), juxtacanalicular tissue (JCT), and the inner wall endothelium of Schlemm's canal (SC), regulates intraocular pressure (IOP) by controlling the aqueous humor outflow resistance. Despite its importance, our understanding of the biomechanics and hydrodynamics within this region remains limited. Fluid-structure interaction (FSI) offers a way to estimate the biomechanical properties of the JCT and SC under various loading and boundary conditions, providing valuable insights that are beyond the reach of current imaging techniques. METHODS In this study, a normal human eye was fixed at a pressure of 7 mm Hg, and two radial wedges of the TM tissues, which included the SC inner wall basement membrane and JCT, were dissected, processed, and imaged using 3D serial block-face scanning electron microscopy (SBF-SEM). Four different sets of images were used to create 3D finite element (FE) models of the JCT and inner wall endothelial cells of SC with their basement membrane. The outer JCT portion was carefully removed as the outflow resistance is not in that region, leaving only the SCE inner wall and a few µm of the tissue, which does contain the resistance. An inverse iterative FE algorithm was then utilized to calculate the unloaded geometry of the JCT/SC complex at an aqueous humor pressure of 0 mm Hg. Then in the model, the intertrabecular spaces, pores, and giant vacuole contents were replaced by aqueous humor, and FSI was employed to pressurize the JCT/SC complex from 0 to 15 mm Hg. RESULTS In the JCT/SC complex, the shear stress of the aqueous humor is not evenly distributed. Areas proximal to the inner wall of SC experience larger stresses, reaching up to 10 Pa, while those closer to the JCT undergo lower stresses, approximately 4 Pa. Within this complex, giant vacuoles with or without I-pore behave differently. Those without I-pores experience a more significant strain, around 14%, compared to those with I-pores, where the strain is roughly 9%. CONCLUSIONS The distribution of aqueous humor wall shear stress is not uniform within the JCT/SC complex, which may contribute to our understanding of the underlying selective mechanisms in the pathway.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States; Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States.
| | - Reza Razaghi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Siddharth Daniel D'costa
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Saeed Torbati
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Sina Ebrahimi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States.
| | | | - Mary J Kelley
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States; Department Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, United States.
| | - Ted S Acott
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States; Department Chemical Physiology & Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, United States.
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States.
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Karimi A, Razaghi R, Kelley MJ, Acott TS, Gong H. Biomechanics of the JCT and SC Inner Wall Endothelial Cells with Their Basement Membrane Using 3D Serial Block-Face Scanning Electron Microscopy. Bioengineering (Basel) 2023; 10:1038. [PMID: 37760140 PMCID: PMC10525990 DOI: 10.3390/bioengineering10091038] [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: 07/07/2023] [Revised: 08/01/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND More than ~70% of the aqueous humor exits the eye through the conventional aqueous outflow pathway that is comprised of the trabecular meshwork (TM), juxtacanalicular tissue (JCT), the inner wall endothelium of Schlemm's canal (SC). The flow resistance in the JCT and SC inner wall basement membrane is thought to play an important role in the regulation of the intraocular pressure (IOP) in the eye, but current imaging techniques do not provide enough information about the mechanics of these tissues or the aqueous humor in this area. METHODS A normal human eye was perfusion-fixed and a radial wedge of the TM tissue from a high-flow region was dissected. The tissues were then sliced and imaged using serial block-face scanning electron microscopy. Slices from these images were selected and segmented to create a 3D finite element model of the JCT and SC cells with an inner wall basement membrane. The aqueous humor was used to replace the intertrabecular spaces, pores, and giant vacuoles, and fluid-structure interaction was employed to couple the motion of the tissues with the aqueous humor. RESULTS Higher tensile stresses (0.8-kPa) and strains (25%) were observed in the basement membrane beneath giant vacuoles with open pores. The volumetric average wall shear stress was higher in SC than in JCT/SC. As the aqueous humor approached the inner wall basement membrane of SC, the velocity of the flow decreased, resulting in the formation of small eddies immediately after the flow left the inner wall. CONCLUSIONS Improved modeling of SC and JCT can enhance our understanding of outflow resistance and funneling. Serial block-face scanning electron microscopy with fluid-structure interaction can achieve this, and the observed micro-segmental flow patterns in ex vivo perfused human eyes suggest a hypothetical mechanism.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97208, USA; (R.R.); (M.J.K.); (T.S.A.)
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97208, USA
| | - Reza Razaghi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97208, USA; (R.R.); (M.J.K.); (T.S.A.)
| | - Mary J. Kelley
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97208, USA; (R.R.); (M.J.K.); (T.S.A.)
- Department Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR 97208, USA
| | - Ted S. Acott
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97208, USA; (R.R.); (M.J.K.); (T.S.A.)
- Department Chemical Physiology & Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR 97208, USA
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA 02118, USA;
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
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Karimi A, Halabian M, Razaghi R, Downs JC, Kelley MJ, Acott TS. Modeling the Endothelial Glycocalyx Layer in the Human Conventional Aqueous Outflow Pathway. Cells 2022; 11:cells11233925. [PMID: 36497183 PMCID: PMC9740116 DOI: 10.3390/cells11233925] [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: 11/02/2022] [Revised: 11/30/2022] [Accepted: 12/03/2022] [Indexed: 12/07/2022] Open
Abstract
A layer of proteoglycans and glycoproteins known as glycocalyx covers the surface of the trabecular meshwork (TM), juxtacanalicular tissue (JCT), and Schlemm's canal (SC) inner wall of the conventional aqueous outflow pathway in the eye. This has been shown to play a role in the mechanotransduction of fluid shear stress and in the regulation of the outflow resistance. The outflow resistance in the conventional outflow pathway is the main determinant of the intraocular pressure (IOP) through an active, two-way, fluid-structure interaction coupling between the outflow tissues and aqueous humor. A 3D microstructural finite element (FE) model of a healthy human eye TM/JCT/SC complex with interspersed aqueous humor was constructed. A very thin charged double layer that represents the endothelial glycocalyx layer covered the surface of the elastic outflow tissues. The aqueous humor was modeled as electroosmotic flow that is charged when it is in contact with the outflow tissues. The electrical-fluid-structure interaction (EFSI) method was used to couple the charged double layer (glycocalyx), fluid (aqueous humor), and solid (outflow tissues). When the IOP was elevated to 15 mmHg, the maximum aqueous humor velocity in the EFSI model was decreased by 2.35 mm/s (9%) compared to the fluid-structure interaction (FSI) model. The charge or electricity in the living human conventional outflow pathway generated by the charged endothelial glycocalyx layer plays a minor biomechanical role in the resultant stresses and strains as well as the hydrodynamics of the aqueous humor.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
- Correspondence:
| | - Mahdi Halabian
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Reza Razaghi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - J. Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Mary J. Kelley
- Departments of Ophthalmology and Integrative Biosciences, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ted S. Acott
- Departments of Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
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Khan MO, Nishi T, Imura S, Seo J, Wang H, Honda Y, Nieman K, Rogers IS, Tremmel JA, Boyd J, Schnittger I, Marsden A. Colocalization of Coronary Plaque with Wall Shear Stress in Myocardial Bridge Patients. Cardiovasc Eng Technol 2022; 13:797-807. [PMID: 35296987 DOI: 10.1007/s13239-022-00616-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 02/25/2022] [Indexed: 01/27/2023]
Abstract
PURPOSE Patients with myocardial bridges (MBs) have a higher prevalence of atherosclerosis. Wall shear stress (WSS) has previously been correlated with plaque in coronary artery disease patients, but such correlations have not been investigated in symptomatic MB patients. The aim of this paper was to use a multi-scale computational fluid dynamics (CFD) framework to simulate hemodynamics in MB patient, and investigate the co-localization of WSS and plaque. METHODS We identified N = 10 patients from a previously reported cohort of 50 symptomatic MB patients, all of whom had plaque in the proximal vessel. Dynamic 3D models were reconstructed from coronary computed tomography angiography (CCTA), intravascular ultrasound (IVUS) and catheter angiograms. CFD simulations were performed to compute WSS proximal to, within and distal to the MB. Plaque was quantified from IVUS images in 2 mm segments and registered to CFD model. Plaque area was compared to absolute and patient-normalized WSS. RESULTS WSS was lower in the proximal segment compared to the bridge segment (6.1 ± 2.9 vs. 16.0 ± 7.1 dynes/cm2, p value < 0.01). Plaque area and plaque burden measured from IVUS peaked at 1-3 cm proximal to the MB entrance, coinciding with the first diagonal branch. Normalized WSS showed a statistically significant moderate correlation with plaque area (r = 0.41, p < 0.01). CONCLUSION WSS may be obtained non-invasively in MB patients and provides a surrogate marker of plaque area. Using CFD, it may be possible to non-invasively assess the extent of plaque area, and identify patients who could benefit from frequent monitoring or medical management.
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Affiliation(s)
- Muhammad Owais Khan
- Department of Pediatrics, Stanford University School of Medicine, 318 Campus Drive, Clark Center E100b, Stanford, CA, 94305-5428, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Takeshi Nishi
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Shinji Imura
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Jongmin Seo
- Department of Pediatrics, Stanford University School of Medicine, 318 Campus Drive, Clark Center E100b, Stanford, CA, 94305-5428, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Hanjay Wang
- Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Yasuhiro Honda
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Koen Nieman
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA.,Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Ian S Rogers
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Jennifer A Tremmel
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Jack Boyd
- Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Ingela Schnittger
- Division of Cardiovascular Medicine, Stanford University School of Medicine and Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Alison Marsden
- Department of Pediatrics, Stanford University School of Medicine, 318 Campus Drive, Clark Center E100b, Stanford, CA, 94305-5428, USA. .,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA. .,Department of Bioengineering, Stanford University, Stanford, CA, USA.
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Weinberg PD. Haemodynamic Wall Shear Stress, Endothelial Permeability and Atherosclerosis-A Triad of Controversy. Front Bioeng Biotechnol 2022; 10:836680. [PMID: 35340842 PMCID: PMC8948426 DOI: 10.3389/fbioe.2022.836680] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/20/2022] [Indexed: 01/13/2023] Open
Abstract
A striking feature of atherosclerosis is its patchy distribution within the vascular system; certain arteries and certain locations within each artery are preferentially affected. Identifying the local risk factors underlying this phenomenon may lead to new therapeutic strategies. The large variation in lesion prevalence in areas of curvature and branching has motivated a search for haemodynamic triggers, particular those related to wall shear stress (WSS). The fact that lesions are rich in blood-derived lipids has motivated studies of local endothelial permeability. However, the location of lesions, the underlying haemodynamic triggers, the role of permeability, the routes by which lipids cross the endothelium, and the mechanisms by which WSS affects permeability have all been areas of controversy. This review presents evidence for and against the current consensus that lesions are triggered by low and/or oscillatory WSS and that this type of shear profile leads to elevated entry of low density lipoprotein (LDL) into the wall via widened intercellular junctions; it also evaluates more recent evidence that lesion location changes with age, that multidirectional shear stress plays a key role, that LDL dominantly crosses the endothelium by transcytosis, and that the link between flow and permeability results from hitherto unrecognised shear-sensitive mediators.
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Choudhury S, Anupindi K, Patnaik BSV. A study on the transport and interaction between blood flow and low-density-lipoprotein in near-wall regions of blood vessels. Comput Methods Biomech Biomed Engin 2021; 24:1473-1487. [PMID: 33966566 DOI: 10.1080/10255842.2021.1893311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Differences in the dynamics and transport of blood make certain regions of the arterial network the preferred sites for initiation and formation of arterial diseases like stenosis and aneurysms. Understanding of such arterial diseases is directly linked to critical hemodynamic parameters such as the wall shear stress (WSS). The present work generalises the influence of WSS on the concentration of LDL that was observed in an earlier study. To this end, a wide variety of simplified flow domain, inspired by the near-wall regions of aneurysms and stenosis, are constructed and analyzed. The effects of pulsatile inflow condition, rheology of blood and curvature of the wall on the correlation between WSS and LDL concentration are investigated. It is demonstrated that the time-scale of variation of lumen-surface-concentration (LSC) of LDL is larger than a single cardiac cycle. As a consequence, the time-average values of WSS are sufficient to locate the regions of higher LSC. This idea is strengthened by making use of simplified flow domain that generates moving stagnation point. Further, it was observed that the rheology of the blood and curvature of the wall does not affect the observed correlation between the WSS and LDL concentration.
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Affiliation(s)
- Satyajit Choudhury
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
| | - Kameswararao Anupindi
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India
| | - B S V Patnaik
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
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Kang H, Yang J, Zhang W, Lu J, Ma X, Sun A, Deng X. Effect of endothelial glycocalyx on water and LDL transport through the rat abdominal aorta. Am J Physiol Heart Circ Physiol 2021; 320:H1724-H1737. [PMID: 33710913 DOI: 10.1152/ajpheart.00861.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/04/2021] [Indexed: 12/13/2022]
Abstract
The surface of vascular endothelial cells (ECs) is covered by a protective negatively charged layer known as the endothelial glycocalyx. Herein, we hypothesized its transport barrier and mechanosensory role in transmural water flux and low-density lipoprotein (LDL) transport in an isolated rat abdominal aorta perfused under 85 mmHg and 20 dyn/cm2 ex vivo. The endothelial glycocalyx was digested by hyaluronidase (HAase) from bovine tests. Water infiltration velocity (Vw) was measured by a graduated pipette. LDL coverage and mean maximum infiltration distance (MMID) in the vessel wall were quantified by confocal laser scanning microscopy. EC apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) technique, and leaky junction rates were evaluated by electron microscopy. The results showed that a 42% degradation of the endothelial glycocalyx by HAase treatment increased Vw, LDL coverage, and MMID. Shear stress increased Vw, which cannot be inhibited by HAase treatment. Four hour-shear application increased about fourfolds of LDL coverage, whereas exerted no significant effects on its MMID, EC apoptosis, and the leaky junctions. On the contrary, 24-h shear exposure has no significant effects on LDL coverage, whereas increased 2.74-folds of MMID and about 53% of EC apoptotic rates that could be inhibited by HAase treatment. These results suggest endothelial glycocalyx acts as a transport barrier by decreasing water and LDL transport, as well as a mechanosensor of shear to regulate EC apoptosis, thus affecting leaky junctions and regulating LDL transport into the vessel wall.NEW & NOTEWORTHY A 42% degradation of the endothelial glycocalyx by hyaluronidase of the isolated rat abdominal aorta facilitated water and LDL transport across the vessel wall, suggesting endothelial glycocalyx as a transport barrier. A 24-h shear exposure increased LDL mean maximum infiltration distance, and enhanced EC apoptosis, which could be both inhibited by hyaluronidase treatment, suggesting endothelial glycocalyx may also act as a mechanosensor of shear to regulate EC apoptosis, thus affecting leaky junctions and regulating LDL transport.
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Affiliation(s)
- Hongyan Kang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jiali Yang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Weichen Zhang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jinyan Lu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xuejiao Ma
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Anqiang Sun
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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Soltany Sadrabadi M, Hedayat M, Borazjani I, Arzani A. Fluid-structure coupled biotransport processes in aortic valve disease. J Biomech 2021; 117:110239. [PMID: 33515904 DOI: 10.1016/j.jbiomech.2021.110239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/22/2020] [Accepted: 01/04/2021] [Indexed: 12/28/2022]
Abstract
Biological transport processes near the aortic valve play a crucial role in calcific aortic valve disease initiation and bioprosthetic aortic valve thrombosis. Hemodynamics coupled with the dynamics of the leaflets regulate these transport patterns. Herein, two-way coupled fluid-structure interaction (FSI) simulations of a 2D bicuspid aortic valve and a 3D mechanical heart valve were performed and coupled with various convective mass transport models that represent some of the transport processes in calcification and thrombosis. Namely, five different continuum transport models were developed to study biochemicals that originate from the blood and the leaflets, as well as residence-time and flow stagnation. Low-density lipoprotein (LDL) and platelet activation were studied for their role in calcification and thrombosis, respectively. Coherent structures were identified using vorticity and Lagrangian coherent structures (LCS) for the 2D and 3D models, respectively. A very close connection between vortex structures and biochemical concentration patterns was shown where different vortices controlled the concentration patterns depending on the transport mechanism. Additionally, the relationship between leaflet concentration and wall shear stress was revealed. Our work shows that blood flow physics and coherent structures regulate the flow-mediated biological processes that are involved in aortic valve calcification and thrombosis, and therefore could be used in the design process to optimize heart valve replacement durability.
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Affiliation(s)
| | - Mohammadali Hedayat
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Iman Borazjani
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA.
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Mahmoudi M, Farghadan A, McConnell DR, Barker AJ, Wentzel JJ, Budoff MJ, Arzani A. The Story of Wall Shear Stress in Coronary Artery Atherosclerosis: Biochemical Transport and Mechanotransduction. J Biomech Eng 2020; 143:1090502. [PMID: 33156343 DOI: 10.1115/1.4049026] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Indexed: 12/20/2022]
Abstract
Coronary artery atherosclerosis is a local, multifactorial, complex disease, and the leading cause of death in the US. Complex interactions between biochemical transport and biomechanical forces influence disease growth. Wall shear stress (WSS) affects coronary artery atherosclerosis by inducing endothelial cell mechanotransduction and by controlling the near-wall transport processes involved in atherosclerosis. Each of these processes is controlled by WSS differently and therefore has complicated the interpretation of WSS in atherosclerosis. In this paper, we present a comprehensive theory for WSS in atherosclerosis. First, a short review of shear stress-mediated mechanotransduction in atherosclerosis was presented. Next, subject-specific computational fluid dynamics (CFD) simulations were performed in ten coronary artery models of diseased and healthy subjects. Biochemical-specific mass transport models were developed to study low-density lipoprotein, nitric oxide, adenosine triphosphate, oxygen, monocyte chemoattractant protein-1, and monocyte transport. The transport results were compared with WSS vectors and WSS Lagrangian coherent structures (WSS LCS). High WSS magnitude protected against atherosclerosis by increasing the production or flux of atheroprotective biochemicals and decreasing the near-wall localization of atherogenic biochemicals. Low WSS magnitude promoted atherosclerosis by increasing atherogenic biochemical localization. Finally, the attracting WSS LCS's role was more complex where it promoted or prevented atherosclerosis based on different biochemicals. We present a summary of the different pathways by which WSS influences coronary artery atherosclerosis and compare different mechanotransduction and biotransport mechanisms.
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Affiliation(s)
- Mostafa Mahmoudi
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
| | - Ali Farghadan
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
| | - Daniel R McConnell
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
| | - Alex J Barker
- Department of Pediatric Radiology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045
| | - Jolanda J Wentzel
- Department of Cardiology, Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | | | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011
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Interaction of arterial proteoglycans with low density lipoproteins (LDLs): From theory to promising therapeutic approaches. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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12
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Mundi S, Massaro M, Scoditti E, Carluccio MA, van Hinsbergh VWM, Iruela-Arispe ML, De Caterina R. Endothelial permeability, LDL deposition, and cardiovascular risk factors-a review. Cardiovasc Res 2019; 114:35-52. [PMID: 29228169 DOI: 10.1093/cvr/cvx226] [Citation(s) in RCA: 182] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022] Open
Abstract
Early atherosclerosis features functional and structural changes in the endothelial barrier function that affect the traffic of molecules and solutes between the vessel lumen and the vascular wall. Such changes are mechanistically related to the development of atherosclerosis. Proatherogenic stimuli and cardiovascular risk factors, such as dyslipidaemias, diabetes, obesity, and smoking, all increase endothelial permeability sharing a common signalling denominator: an imbalance in the production/disposal of reactive oxygen species (ROS), broadly termed oxidative stress. Mostly as a consequence of the activation of enzymatic systems leading to ROS overproduction, proatherogenic factors lead to a pro-inflammatory status that translates in changes in gene expression and functional rearrangements, including changes in the transendothelial transport of molecules, leading to the deposition of low-density lipoproteins (LDL) and the subsequent infiltration of circulating leucocytes in the intima. In this review, we focus on such early changes in atherogenesis and on the concept that proatherogenic stimuli and risk factors for cardiovascular disease, by altering the endothelial barrier properties, co-ordinately trigger the accumulation of LDL in the intima and ultimately plaque formation.
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Affiliation(s)
- Santa Mundi
- Department of Biological and Environmental Science and Technology (DISTEBA), University of Salento, via Monteroni, 73100, Lecce, Italy
| | - Marika Massaro
- National Research Council (CNR), Department of Biomedical sciences, Institute of Clinical Physiology, Via Monteroni, 73100, Lecce, Italy
| | - Egeria Scoditti
- National Research Council (CNR), Department of Biomedical sciences, Institute of Clinical Physiology, Via Monteroni, 73100, Lecce, Italy
| | - Maria Annunziata Carluccio
- National Research Council (CNR), Department of Biomedical sciences, Institute of Clinical Physiology, Via Monteroni, 73100, Lecce, Italy
| | - Victor W M van Hinsbergh
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat, NL-1081 BT, Amsterdam, The Netherlands
| | - Marial Luisa Iruela-Arispe
- Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute, University of California, 610 Charles E Young Dr S, 90095, Los Angeles, USA; and
| | - Raffaele De Caterina
- Department of Neuroscience, Imaging and Clinical Science and Institute of Advanced Biomedical Technologies, University G. D'Annunzio, via dei Vestini, 66100 Chieti, Italy
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Gabriel SA, Ding Y, Feng Y. Modelling the period-average transport of species within pulsatile blood flow. J Theor Biol 2018; 457:258-269. [DOI: 10.1016/j.jtbi.2018.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/31/2018] [Accepted: 07/06/2018] [Indexed: 12/23/2022]
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14
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De Nisco G, Zhang P, Calò K, Liu X, Ponzini R, Bignardi C, Rizzo G, Deng X, Gallo D, Morbiducci U. What is needed to make low-density lipoprotein transport in human aorta computational models suitable to explore links to atherosclerosis? Impact of initial and inflow boundary conditions. J Biomech 2018; 68:33-42. [DOI: 10.1016/j.jbiomech.2017.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/05/2017] [Accepted: 12/07/2017] [Indexed: 12/26/2022]
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15
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Li X, Liu X, Zhang P, Feng C, Sun A, Kang H, Deng X, Fan Y. Numerical simulation of haemodynamics and low-density lipoprotein transport in the rabbit aorta and their correlation with atherosclerotic plaque thickness. J R Soc Interface 2017; 14:rsif.2017.0140. [PMID: 28424305 DOI: 10.1098/rsif.2017.0140] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 03/20/2017] [Indexed: 12/25/2022] Open
Abstract
Two mechanisms of shear stress and mass transport have been recognized to play an important role in the development of localized atherosclerosis. However, their relationship and roles in atherogenesis are still obscure. It is necessary to investigate quantitatively the correlation among low-density lipoproteins (LDL) transport, haemodynamic parameters and plaque thickness. We simulated blood flow and LDL transport in rabbit aorta using computational fluid dynamics and evaluated plaque thickness in the aorta of a high-fat-diet rabbit. The numerical results show that regions with high luminal LDL concentration tend to have severely negative haemodynamic environments (HEs). However, for regions with moderately and slightly high luminal LDL concentration, the relationship between LDL concentration and the above haemodynamic indicators is not clear cut. Point-by-point correlation with experimental results indicates that severe atherosclerotic plaque corresponds to high LDL concentration and seriously negative HEs, less severe atherosclerotic plaque is related to either moderately high LDL concentration or moderately negative HEs, and there is almost no atherosclerotic plaque in regions with both low LDL concentration and positive HEs. In conclusion, LDL distribution is closely linked to blood flow transport, and the synergetic effects of luminal surface LDL concentration and wall shear stress-based haemodynamic indicators may determine plaque thickness.
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Affiliation(s)
- Xiaoyin Li
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Xiao Liu
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Peng Zhang
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Chenglong Feng
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Anqiang Sun
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Hongyan Kang
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China .,National Research Center for Rehabilitation Technical Aids, Beijing, People's Republic of China
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16
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Khosravi A, Shirazi HA, Asnafi A, Karimi A. A fully analytical approach to investigate the electro-viscous effect of the endothelial glycocalyx layer on the microvascular blood flow. Clin Chim Acta 2017; 472:5-12. [PMID: 28694125 DOI: 10.1016/j.cca.2017.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 01/22/2023]
Abstract
BACKGROUND Recently, the glycocalyx lining the endothelial surface has emerged as a structure of fundamental importance to a wide range of phenomena that has undeniable effect on cardiovascular health and disease. With respect to the blood flow in small vessels, it has been experimentally reported that the glycocalyx layer causes additional resistance to the flow. METHODS The hypothesis of glycocalyx resistance against the blood flow, considered as two-phase layer fluid through a small blood vessel, was theoretically evaluated. To do that, a very thin electric double layer (EDL) was considered and the fluid flow was modeled by the well-known Poisson and Boltzmann equations in micro-fluidics alongside the general Navier-Stokes equation. Finally, a complete analytical solution for this particular case was developed. RESULTS The results confirmed the previous findings indicated that the negatively charged glycocalyx layer has no effect on the macro/micro scale blood flow. Here and in the nano-scale, slightly influence was observed and reported in this study. CONCLUSION Moreover, more details about the thin electrically significant layer, close to the EDL, would be delineate to better recognition of electro-viscous effect caused by the endothelial glycocalyx near microvascular walls.
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Affiliation(s)
- Arezoo Khosravi
- Atherosclerosis Research Center, Baqiyatallah University of Medical Science, Tehran, Iran
| | - Hadi Asgharzadeh Shirazi
- School of Mechanical Engineering, Iran University of Science and Technology, Narmak, 16846-13114 Tehran, Iran
| | - Alireza Asnafi
- School of Mechanical Engineering, Shiraz University, Shiraz 71348-13668, Iran.
| | - Alireza Karimi
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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Arzani A, Gambaruto AM, Chen G, Shadden SC. Wall shear stress exposure time: a Lagrangian measure of near-wall stagnation and concentration in cardiovascular flows. Biomech Model Mechanobiol 2016; 16:787-803. [DOI: 10.1007/s10237-016-0853-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/08/2016] [Indexed: 12/18/2022]
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18
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Wang Z, Liu X, Kang H, Sun A, Fan Y, Deng X. Enhanced accumulation of LDLs within the venous graft wall induced by elevated filtration rate may account for its accelerated atherogenesis. Atherosclerosis 2014; 236:198-206. [DOI: 10.1016/j.atherosclerosis.2014.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 06/22/2014] [Accepted: 07/09/2014] [Indexed: 12/26/2022]
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