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Design and Comparison of Large Vessel Stents: Balloon Expandable and Self-Expanding Peripheral Arterial Stents. Interv Cardiol Clin 2017; 5:365-380. [PMID: 28582034 DOI: 10.1016/j.iccl.2016.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Endovascular stenting has evolved over the last 50 years since its inception into the framework of management of vascular atherosclerotic disease. Stent design has evolved as lesion complexity has increased. Nevertheless, certain first principles regarding stent design have been recapitulated time and again with every iteration of endovascular stents. This article reviews principles of endovascular stent design and compares and contrasts key aspects of balloon expandable and self-expanding stents.
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102
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Fulker D, Simmons A, Barber T. Computational Model of the Arterial and Venous Needle During Hemodialysis. J Biomech Eng 2016; 139:2545810. [DOI: 10.1115/1.4034429] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Indexed: 11/08/2022]
Abstract
Arteriovenous fistulae (AVF) are the favored choice of vascular access but still have poor long-term success. Hemodynamic parameters play an important role in vascular health and have been linked to the development of intimal hyperplasia (IH), a pathological growth of the blood vessel initiated by injury. This study aimed to investigate the hemodynamics surrounding the arterial needle (AN) and venous needle (VN), using computational fluid dynamics. A range of blood flow rates, needle positions, and needle orientations were examined. Disturbed flows were found around AN tip in both antegrade and retrograde orientations, which result in regions of high residency time on the surface of the vein and may disrupt endothelial function. Conversely, a high speed jet exits the VN, which produced high wall shear stresses (WSSs) at the point of impingement which can damage the endothelium. The secondary flows produced by jet dissipation also resulted in regions of high residency time, which may influence endothelial structure, leading to IH. The use of shallow needle angles, a blood flow rate of approximately 300 ml/min, and placement of the needle tip away from the walls of the vein mitigates this risk.
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Affiliation(s)
- David Fulker
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington Campus, Kensington, NSW 2025, Australia e-mail:
| | - Anne Simmons
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington Campus, Kensington, NSW 2025, Australia e-mail:
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington Campus, Kensington, NSW 2025, Australia e-mail:
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Casey DP, Schneider AC, Ueda K. Influence of chronic endurance exercise training on conduit artery retrograde and oscillatory shear in older adults. Eur J Appl Physiol 2016; 116:1931-40. [PMID: 27497720 DOI: 10.1007/s00421-016-3445-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/26/2016] [Indexed: 01/12/2023]
Abstract
PURPOSE With aging, there tends to be an increase in retrograde and oscillatory shear in peripheral conduit arteries of humans. Whether the increase in shear rate is due to the aging process or an effect of a less active lifestyle that often accompanies aging is unknown. Therefore, we examined whether chronic endurance exercise training attenuates conduit artery retrograde and oscillatory shear in older adults. METHODS Brachial and common femoral artery mean blood velocities and diameter were determined via Doppler ultrasound under resting conditions, and shear rate was calculated in 13 young (24 ± 2 years), 17 older untrained (66 ± 3 years), and 16 older endurance exercise-trained adults (66 ± 7 years). RESULTS Brachial artery retrograde (-9.1 ± 6.4 vs. -12.6 ± 9.4 s(-1); P = 0.35) and oscillatory (0.14 ± 0.08 vs. 0.14 ± 0.08 arbitrary units; P = 0.99) shear were similar between the older trained and untrained groups, whereas brachial artery retrograde and oscillatory shear were greater in older untrained compared to young adults (-5.0 ± 3.4, 0.08 ± 0.05 s(-1) arbitrary units, P = 0.017 and 0.048, respectively). There was no difference between the young and older trained brachial retrograde (P = 0.29) and oscillatory (P = 0.07) shear. Common femoral artery retrograde (-6.3 ± 2.9 s(-1)) and oscillatory (0.21 ± 0.08 arbitrary units) shear were reduced in older trained compared to the older untrained group (-10.4 ± 4.1 and 0.30 ± 0.09 s(-1) arbitrary units, both P = 0.005 and 0.006, respectively), yet similar to young adults (-7.1 ± 3.5 and 0.19 ± 0.06 s(-1) arbitrary units, P = 0.81 and 0.87, respectively). CONCLUSION Our results suggest that chronic endurance exercise training in older adults ameliorates retrograde and oscillatory shear rate patterns, particularly in the common femoral artery.
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Affiliation(s)
- Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA. .,Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA. .,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA.
| | - Aaron C Schneider
- Department of Health and Human Physiology, University of Iowa, Iowa, IA, 52242, USA
| | - Kenichi Ueda
- Department of Anesthesia, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA
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104
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KARIMI SAFOORA, DADVAR MITRA, DABIR BAHRAM. NUMERICAL MODELING OF ATHEROSCLEROSIS LESION EVOLUTION IN TIME I. INITIAL STAGE OF THE DISEASE. J MECH MED BIOL 2016. [DOI: 10.1142/s0219519416500688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Atherosclerosis is one of the main causes of death in the developed world. The disease, which is an inflammatory disease, has been the focus of many studies. A few studies attempted to model atherosclerosis lesion development mathematically while no attention has been paid to the multistage nature of the disease. The present study provides a mathematical model for atherosclerosis evolution by focusing on the inflammatory responses of the initial stage of the disease. In the model, the inflammatory response in type I lesion, which includes endothelium dysfunction, LDL oxidation, monocytes entry, foam cell formation and intima property changes, are coupled with the transport equations of blood and LDL in lumen and arterial wall. The innovation of the model is determination of the duration of the initial stage of lesion propagation for a specific patient while the presence of leaky junction in endothelial layer and LDL oxidation in the intima layer are considered. The greatest advantage of the study in comparison with previous studies is to provide a model for the initiating stage of the atherosclerosis development so that a more precise result of the disease evolution is obtained.
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Affiliation(s)
- SAFOORA KARIMI
- Department of Chemical Engineering, Jundi-Shapur University of Technology, Dezful 64616-18674, Iran
| | - MITRA DADVAR
- Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - BAHRAM DABIR
- Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
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105
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Qiao C, Meng F, Jang I, Jo H, Chen YE, Zhang J. Deep transcriptomic profiling reveals the similarity between endothelial cells cultured under static and oscillatory shear stress conditions. Physiol Genomics 2016; 48:660-6. [PMID: 27449656 DOI: 10.1152/physiolgenomics.00025.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/17/2016] [Indexed: 01/26/2023] Open
Abstract
Atherosclerosis is a multifactorial disease that preferentially develops in specific regions in the arterial tree. This characteristic is mainly attributed to the unique pattern of hemodynamic shear stress in vivo. High laminar shear stress (LS) found in straight lumen exerts athero-protective effects. Low or oscillatory shear stress (OS) present in regions of lesser curvature and arterial bifurcations predisposes arterial intima to atherosclerosis. Shear stress-regulated endothelial function plays an important role in the process of atherosclerosis. Most in vitro research studies focusing on the molecular mechanisms of endothelial function are performed in endothelial cells (ECs) under cultured static (ST) condition. Some findings, however, are not recapitulated in subsequent translational studies, mostly likely due to the missing biomechanical milieu. Here, we profiled the whole transcriptome of primary human coronary arterial endothelial cells (HCAECs) under different shear stress conditions with RNA sequencing. Among 16,313 well-expressed genes, we detected 8,177 that were differentially expressed in OS vs. LS conditions and 9,369 in ST vs. LS conditions. Notably, only 1,618 were differentially expressed in OS vs. ST conditions. Hierarchical clustering of ECs demonstrated a strong similarity between ECs under OS and ST conditions at the transcriptome level. Subsequent pairwise heat mapping and principal component analysis gave further weight to the similarity. At the individual gene level, expressional analysis of representative well-known genes as well as novel genes showed a comparable amount at mRNA and protein levels in ECs under ST and OS conditions. In conclusion, the present work compared the whole transcriptome of HCAECs under different shear stress conditions at the transcriptome level as well as at the individual gene level. We found that cultured ECs are significantly different from those under LS conditions. Thus using cells under ST conditions is unlikely to elucidate endothelial physiology. Given the revealed high similarities of the endothelial transcriptome under OS and ST conditions, it may be helpful to understand the underlying mechanisms of OS-induced endothelial dysfunction from static cultured endothelial studies.
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Affiliation(s)
- Congzhen Qiao
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan; Frankel Cardiovascular Center, University of Michigan, Ann Arbor, Michigan
| | - Fan Meng
- Department of Psychiatry and Molecular and Behavioral Neuroscience Institute, University of Michigan Medical Center, Ann Arbor, Michigan; and
| | - Inhwan Jang
- Wallace H. Coulter Department of Biomedical Engineering, Division of Cardiology, Department of Medicine, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Hanjoong Jo
- Wallace H. Coulter Department of Biomedical Engineering, Division of Cardiology, Department of Medicine, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Y Eugene Chen
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan; Frankel Cardiovascular Center, University of Michigan, Ann Arbor, Michigan
| | - Jifeng Zhang
- Frankel Cardiovascular Center, University of Michigan, Ann Arbor, Michigan;
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Chung J, Shim H, Kim K, Lee D, Kim WJ, Kang DH, Kang SW, Jo H, Kwon K. Discovery of novel peptides targeting pro-atherogenic endothelium in disturbed flow regions -Targeted siRNA delivery to pro-atherogenic endothelium in vivo. Sci Rep 2016; 6:25636. [PMID: 27173134 PMCID: PMC4901192 DOI: 10.1038/srep25636] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/20/2016] [Indexed: 01/27/2023] Open
Abstract
Atherosclerosis occurs preferentially in arterial regions exposed to disturbed blood flow. Targeting these pro-atherogenic regions is a potential anti-atherogenic therapeutic approach, but it has been extremely challenging. Here, using in vivo phage display approach and the partial carotid ligation model of flow-induced atherosclerosis in mouse, we identified novel peptides that specifically bind to endothelial cells (ECs) exposed to disturbed flow condition in pro-atherogenic regions. Two peptides, CLIRRTSIC and CPRRSHPIC, selectively bound to arterial ECs exposed to disturbed flow not only in the partially ligated carotids but also in the lesser curvature and branching point of the aortic arch in mice as well as human pulmonary artery branches. Peptides were conjugated to branched polyethylenimine-polyethylene glycol polymer to generate polyplexes carrying siRNA targeting intercellular adhesion molecule-1 (siICAM-1). In mouse model, CLIRRTSIC polyplexes carrying si-ICAM-1 specifically bound to endothelium in disturbed flow regions, reducing endothelial ICAM-1 expression. Mass spectrometry analysis revealed that non-muscle myosin heavy chain II A (NMHC IIA) is a protein targeted by CLIRRTSIC peptide. Further studies showed that shear stress regulates NMHC IIA expression and localization in ECs. The CLIRRTSIC is a novel peptide that could be used for targeted delivery of therapeutics such as siRNAs to pro-atherogenic endothelium.
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Affiliation(s)
- Jihwa Chung
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul,158-710, Republic of Korea
| | - Hyunbo Shim
- Departments of Bioinspired Science and Life Science, Ewha Womans University, 11-1 Daehyun-dong, Seodaemoon-gu, Seoul, 120-750, Republic of Korea
| | - Kwanchang Kim
- Department of Thoracic surgery, School of Medicine, Ewha Womans University, Seoul, 158-710, Republic of Korea
| | - Duhwan Lee
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS), and Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Won Jong Kim
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS), and Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Dong Hoon Kang
- Department of Life Science, College of Natural Science, Ewha Womans University, 11-1 Daehyun-dong, Seodaemoon-gu, Seoul, 120-750, Republic of Korea
| | - Sang Won Kang
- Department of Life Science, College of Natural Science, Ewha Womans University, 11-1 Daehyun-dong, Seodaemoon-gu, Seoul, 120-750, Republic of Korea
| | - Hanjoong Jo
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Kihwan Kwon
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul,158-710, Republic of Korea.,Department of Internal Medicine, Cardiology Division, School of Medicine, Ewha Womans University, Seoul, 158-710, Republic of Korea
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Buckling Reduces eNOS Production and Stimulates Extracellular Matrix Remodeling in Arteries in Organ Culture. Ann Biomed Eng 2016; 44:2840-50. [PMID: 26913855 DOI: 10.1007/s10439-016-1571-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 02/17/2016] [Indexed: 12/26/2022]
Abstract
Artery buckling alters the fluid shear stress and wall stress in the artery but its temporal effect on vascular wall remodeling is poorly understood. The purpose of this study was to investigate the early effect of artery buckling on endothelial nitric oxide synthase (eNOS) expression and extracellular matrix remodeling. Bilateral porcine carotid arteries were maintained in an ex vivo organ culture system with and without buckling while under the same physiological pressure and flow rate for 3-7 days. Matrix metalloproteinase-2 (MMP-2), MMP-9, fibronectin, elastin, collagen I, III and IV, tissue inhibitor of metalloproteinase-2 (TIMP-2), and eNOS were determined using Western blotting and immunohistochemistry. Our results showed that MMP-2 expression level was significantly higher in buckled arteries than in the controls and higher at the inner curve than at the outer curve of buckled arteries, while collagen IV content showed an opposite trend, suggesting that artery buckling increased MMP-2 expression and collagen IV degradation in a site-specific fashion. However, no differences for MMP-9, fibronectin, elastin, collagen I, III, and TIMP-2 were observed among the outer and inner curve sides of buckled arteries and straight controls. Additionally, eNOS expression was significantly decreased in buckled arteries. These results suggest that artery buckling triggers uneven wall remodeling that could lead to development of tortuous arteries.
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108
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Blaeser A, Duarte Campos DF, Puster U, Richtering W, Stevens MM, Fischer H. Controlling Shear Stress in 3D Bioprinting is a Key Factor to Balance Printing Resolution and Stem Cell Integrity. Adv Healthc Mater 2016; 5:326-33. [PMID: 26626828 DOI: 10.1002/adhm.201500677] [Citation(s) in RCA: 431] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 10/05/2015] [Indexed: 11/10/2022]
Abstract
A microvalve-based bioprinting system for the manufacturing of high-resolution, multimaterial 3D-structures is reported. Applying a straightforward fluid-dynamics model, the shear stress at the nozzle site can precisely be controlled. Using this system, a broad study on how cell viability and proliferation potential are affected by different levels of shear stress is conducted. Complex, multimaterial 3D structures are printed with high resolution. This work pioneers the investigation of shear stress-induced cell damage in 3D bioprinting and might help to comprehend and improve the outcome of cell-printing studies in the future.
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Affiliation(s)
- Andreas Blaeser
- Department of Dental Materials and Biomaterials Research; RWTH Aachen University Hospital; Pauwelsstrasse 30 52074 Aachen Germany
| | - Daniela Filipa Duarte Campos
- Department of Dental Materials and Biomaterials Research; RWTH Aachen University Hospital; Pauwelsstrasse 30 52074 Aachen Germany
| | - Uta Puster
- Department of Dental Materials and Biomaterials Research; RWTH Aachen University Hospital; Pauwelsstrasse 30 52074 Aachen Germany
| | - Walter Richtering
- Institute of Physical Chemistry; RWTH Aachen University; Landoltweg 2 52074 Aachen Germany
| | - Molly M. Stevens
- Department of Materials; Department of Bioengineering and Institute of Biomedical Engineering; Imperial College London; London SW7 2AZ London UK
| | - Horst Fischer
- Department of Dental Materials and Biomaterials Research; RWTH Aachen University Hospital; Pauwelsstrasse 30 52074 Aachen Germany
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109
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Nakayama KH, Surya VN, Gole M, Walker T, Yang W, Lai ES, Ostrowski M, Fuller GG, Dunn AR, Huang NF. Nanoscale Patterning of Extracellular Matrix Alters Endothelial Function under Shear Stress. NANO LETTERS 2016; 16:410-419. [PMID: 26670737 PMCID: PMC4758680 DOI: 10.1021/acs.nanolett.5b04028] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The role of nanotopographical extracellular matrix (ECM) cues in vascular endothelial cell (EC) organization and function is not well-understood, despite the composition of nano- to microscale fibrillar ECMs within blood vessels. Instead, the predominant modulator of EC organization and function is traditionally thought to be hemodynamic shear stress, in which uniform shear stress induces parallel-alignment of ECs with anti-inflammatory function, whereas disturbed flow induces a disorganized configuration with pro-inflammatory function. Since shear stress acts on ECs by applying a mechanical force concomitant with inducing spatial patterning of the cells, we sought to decouple the effects of shear stress using parallel-aligned nanofibrillar collagen films that induce parallel EC alignment prior to stimulation with disturbed flow resulting from spatial wall shear stress gradients. Using real time live-cell imaging, we tracked the alignment, migration trajectories, proliferation, and anti-inflammatory behavior of ECs when they were cultured on parallel-aligned or randomly oriented nanofibrillar films. Intriguingly, ECs cultured on aligned nanofibrillar films remained well-aligned and migrated predominantly along the direction of aligned nanofibrils, despite exposure to shear stress orthogonal to the direction of the aligned nanofibrils. Furthermore, in stark contrast to ECs cultured on randomly oriented films, ECs on aligned nanofibrillar films exposed to disturbed flow had significantly reduced inflammation and proliferation, while maintaining intact intercellular junctions. This work reveals fundamental insights into the importance of nanoscale ECM interactions in the maintenance of endothelial function. Importantly, it provides new insight into how ECs respond to opposing cues derived from nanotopography and mechanical shear force and has strong implications in the design of polymeric conduits and bioengineered tissues.
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Affiliation(s)
- Karina H. Nakayama
- Stanford Cardiovascular Institute, Stanford, CA
- Department of Cardiothoracic Surgery, Stanford School of Medicine, Stanford, CA
- Veterans Affairs Palo Alto Health Care System, Palo Alto
| | - Vinay N. Surya
- Stanford Cardiovascular Institute, Stanford, CA
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, CA
| | - Monica Gole
- Veterans Affairs Palo Alto Health Care System, Palo Alto
| | - Travis Walker
- Department of Chemical Engineering, Oregon State University, Corvallis, OR
| | - Weiguang Yang
- Department of Pediatrics, Stanford School of Medicine, Stanford, CA
| | - Edwina S. Lai
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, CA
| | - Maggie Ostrowski
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, CA
| | - Gerald G. Fuller
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, CA
| | - Alexander R. Dunn
- Stanford Cardiovascular Institute, Stanford, CA
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, CA
| | - Ngan F. Huang
- Stanford Cardiovascular Institute, Stanford, CA
- Department of Cardiothoracic Surgery, Stanford School of Medicine, Stanford, CA
- Veterans Affairs Palo Alto Health Care System, Palo Alto
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110
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Lukas K, Thomas U, Gessner A, Wehner D, Schmid T, Schmid C, Lehle K. Plasma functionalization of polycarbonaturethane to improve endothelialization—Effect of shear stress as a critical factor for biocompatibility control. J Biomater Appl 2016; 30:1417-28. [DOI: 10.1177/0885328215626072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Medical devices made of polycarbonaturethane (PCU) combine excellent mechanical properties and little biological degradation, but restricted hemocompatibility. Modifications of PCU might reduce platelet adhesion and promote stable endothelialization. PCU was modified using gas plasma treatment, binding of hydrogels, and coupling of cell-active molecules (modified heparin, anti-thrombin III (ATIII), argatroban, fibronectin, laminin-nonapeptide, peptides with integrin-binding arginine-glycine-aspartic acid (RGD) motif). Biocompatibility was verified with static and dynamic cell culture techniques. Blinded analysis focused on improvement in endothelial cell (EC) adhesion/proliferation, anti-thrombogenicity, reproducible manufacturing process, and shear stress tolerance of ECs. EC adhesion and antithrombogenicity were achieved with 9/35 modifications. Additionally, 6/9 stimulated EC proliferation and 3/6 modification processes were highly reproducible for endothelialization. The latter modifications comprised immobilization of ATIII (A), polyethyleneglycole-diamine-hydrogel (E) and polyethylenimine-hydrogel connected with modified heparin (IH). Under sheer stress, only the IH modification improved EC adhesion within the graft. However, ECs did not arrange in flow direction and cell anchorage was restricted. Despite large variation in surface modification chemistry and improved EC adhesion under static culture conditions, additional introduction of shear stress foiled promising preliminary data. Therefore, biocompatibility testing required not only static tests but also usage of physiological conditions such as shear stress in the case of vascular grafts.
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Affiliation(s)
- Karin Lukas
- IMHR, Institute for Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | | | - André Gessner
- IMHR, Institute for Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | | | | | - Christof Schmid
- Department of Cardiothoracic Surgery, University Hospital Regensburg, Regensburg, Germany
| | - Karla Lehle
- Department of Cardiothoracic Surgery, University Hospital Regensburg, Regensburg, Germany
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111
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Thomas A, Daniel Ou-Yang H, Lowe-Krentz L, Muzykantov VR, Liu Y. Biomimetic channel modeling local vascular dynamics of pro-inflammatory endothelial changes. BIOMICROFLUIDICS 2016; 10:014101. [PMID: 26858813 PMCID: PMC4706543 DOI: 10.1063/1.4936672] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 11/16/2015] [Indexed: 05/08/2023]
Abstract
Endothelial cells form the inner lining of blood vessels and are exposed to various factors like hemodynamic conditions (shear stress, laminar, and turbulent flow), biochemical signals (cytokines), and communication with other cell types (smooth muscle cells, monocytes, platelets, etc.). Blood vessel functions are regulated by interactions among these factors. The occurrence of a pathological condition would lead to localized upregulation of cell adhesion molecules on the endothelial lining of the blood vessel. This process is promoted by circulating cytokines such as tumor necrosis factor-alpha, which leads to expression of intercellular adhesion molecule-1 (ICAM-1) on the endothelial cell surface among other molecules. ICAM-1 is critical in regulating endothelial cell layer dynamic integrity and cytoskeletal remodeling and also mediates direct cell-cell interactions as part of inflammatory responses and wound healing. In this study, we developed a biomimetic blood vessel model by culturing confluent, flow aligned, endothelial cells in a microfluidic platform, and performed real time in situ characterization of flow mediated localized pro-inflammatory endothelial activation. The model mimics the physiological phenomenon of cytokine activation of endothelium from the tissue side and studies the heterogeneity in localized surface ICAM-1 expression and F-actin arrangement. Fluorescent antibody coated particles were used as imaging probes for identifying endothelial cell surface ICAM-1 expression. The binding properties of particles were evaluated under flow for two different particle sizes and antibody coating densities. This allowed the investigation of spatial resolution and accessibility of ICAM-1 molecules expressed on the endothelial cells, along with their sensitivity in receptor-ligand recognition and binding. This work has developed an in vitro blood vessel model that can integrate various heterogeneous factors to effectively mimic a complex endothelial microenvironment and can be potentially applied for relevant blood vessel mechanobiology studies.
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Affiliation(s)
- Antony Thomas
- Bioengineering Program, Lehigh University , Bethlehem, Pennsylvania 18015, USA
| | | | | | - Vladimir R Muzykantov
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine , Philadelphia, Pennsylvania 19104, USA
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112
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D'Auria F, Centurione L, Centurione MA, Angelini A, Di Pietro R. Tumor Necrosis Factor Related Apoptosis Inducing Ligand (Trail) in endothelial response to biomechanical and biochemical stresses in arteries. J Cell Biochem 2015; 116:2427-34. [PMID: 25974396 DOI: 10.1002/jcb.25223] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/07/2015] [Indexed: 02/05/2023]
Abstract
Shear stress is determined by three physical components described in a famous triad: blood flow, blood viscosity and vessel geometry. Through the direct action on endothelium, shear stress is able to radically interfere with endothelial properties and the physiology of the vascular wall. Endothelial cells (ECs) have also to sustain biochemical stresses represented by chemokines, growth factors, cytokines, complement, hormones, nitric oxide (NO), oxygen and reactive oxygen species (ROS). Many growth factors, cytokines, chemokines, hormones, and chemical substances, like NO, act and regulate endothelium functions and homeostasis. Among these cytokines Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL) has been assigned a regulatory role in ECs physiology and physiopathology. Thus, the aim of this review is to provide a general overview of the endothelial response pathways after different types of biomechanical and biochemical stress in in vitro models and to analyze the crucial role of TRAIL under pathological conditions of the cardiocirculatory system like atherosclerosis, coronary artery disease, and diabetes.
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Affiliation(s)
- F D'Auria
- Department of Cardiac and Vascular Surgery, Campus Bio-Medico University of Rome, Rome, Italy
| | - L Centurione
- Department of Medicine and Ageing Sciences, G. d'Annunzio University, Chieti, Pescara, Italy
| | - M A Centurione
- Institute of Molecular Genetics, National Research Council-Pavia, Section of Chieti, Italy
| | - A Angelini
- Department of Medicine and Ageing Sciences, G. d'Annunzio University, Chieti, Pescara, Italy
- Ageing Research Center, CeSI, G. d'Annunzio University Foundation, Chieti, Italy
| | - R Di Pietro
- Department of Medicine and Ageing Sciences, G. d'Annunzio University, Chieti, Pescara, Italy
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113
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Effects of Vessel Tortuosity on Coronary Hemodynamics: An Idealized and Patient-Specific Computational Study. Ann Biomed Eng 2015; 44:2228-39. [PMID: 26498931 DOI: 10.1007/s10439-015-1492-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 10/16/2015] [Indexed: 01/09/2023]
Abstract
Although coronary tortuosity can influence the hemodynamics of coronary arteries, the relationship between tortuosity and flow has not been thoroughly investigated partly due to the absence of a widely accepted definition of tortuosity and the lack of patient-specific studies that analyze complete coronary trees. Using a computational approach we investigated the effects of tortuosity on coronary flow parameters including pressure drop, wall shear stress, and helical flow strength as measured by helicity intensity. Our analysis considered idealized and patient-specific geometries. Overall results indicate that perfusion pressure decreases with increased tortuosity, but the patient-specific results show that more tortuous vessels have higher physiological wall shear stress values. Differences between the idealized and patient-specific results reveal that an accurate representation of coronary tortuosity must account for all relevant geometric aspects, including curvature imposed by the heart shape. The patient-specific results exhibit a strong correlation between tortuosity and helicity intensity, and the corresponding helical flow contributes directly to the observed increase in wall shear stress. Therefore, helicity intensity may prove helpful in developing a universal parameter to describe tortuosity and assess its impact on patient health. Our data suggest that increased tortuosity could have a deleterious impact via a reduction in coronary perfusion pressure, but the attendant increase in wall shear stress could afford protection against atherosclerosis.
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114
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Kokkalis E, Aristokleous N, Houston JG. Haemodynamics and Flow Modification Stents for Peripheral Arterial Disease: A Review. Ann Biomed Eng 2015; 44:466-76. [PMID: 26467554 PMCID: PMC4764640 DOI: 10.1007/s10439-015-1483-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 10/07/2015] [Indexed: 02/02/2023]
Abstract
Endovascular stents are widely used for the treatment of peripheral arterial disease (PAD). However, the development of in-stent restenosis and downstream PAD progression remain a challenge. Stent revascularisation of PAD causes arterial trauma and introduces abnormal haemodynamics, which initiate complicated biological processes detrimental to the arterial wall. The interaction between stent struts and arterial cells in contact, and the blood flow field created in a stented region, are highly affected by stent design. Spiral flow is known as a normal physiologic characteristic of arterial circulation and is believed to prevent the development of flow disturbances. This secondary flow motion is lost in atheromatous disease and its re-introduction after endovascular treatment of PAD has been suggested as a method to induce stabilised and coherent haemodynamics. Stent designs able to generate spiral flow may support endothelial function and therefore increase patency rates. This review is focused on secondary flow phenomena in arteries and the development of flow modification stent technologies for the treatment of PAD.
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Affiliation(s)
- Efstratios Kokkalis
- Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Mail Box 1, Dundee, DD1 9SY, United Kingdom
| | - Nicolas Aristokleous
- Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Mail Box 1, Dundee, DD1 9SY, United Kingdom.
| | - J Graeme Houston
- Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Mail Box 1, Dundee, DD1 9SY, United Kingdom
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115
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Chung J, Kim KH, Lee SC, An SH, Kwon K. Ursodeoxycholic Acid (UDCA) Exerts Anti-Atherogenic Effects by Inhibiting Endoplasmic Reticulum (ER) Stress Induced by Disturbed Flow. Mol Cells 2015; 38:851-8. [PMID: 26442866 PMCID: PMC4625066 DOI: 10.14348/molcells.2015.0094] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/08/2015] [Accepted: 07/17/2015] [Indexed: 11/27/2022] Open
Abstract
Disturbed blood flow with low-oscillatory shear stress (OSS) is a predominant atherogenic factor leading to dysfunctional endothelial cells (ECs). Recently, it was found that disturbed flow can directly induce endoplasmic reticulum (ER) stress in ECs, thereby playing a critical role in the development and progression of atherosclerosis. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid, has long been used to treat chronic cholestatic liver disease and is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, its role in atherosclerosis remains unexplored. In this study, we demonstrated the anti-atherogenic activity of UDCA via inhibition of disturbed flow-induced ER stress in atherosclerosis. UDCA effectively reduced ER stress, resulting in a reduction in expression of X-box binding protein-1 (XBP-1) and CEBP-homologous protein (CHOP) in ECs. UDCA also inhibits the disturbed flow-induced inflammatory responses such as increases in adhesion molecules, monocyte adhesion to ECs, and apoptosis of ECs. In a mouse model of disturbed flow-induced atherosclerosis, UDCA inhibits atheromatous plaque formation through the alleviation of ER stress and a decrease in adhesion molecules. Taken together, our results revealed that UDCA exerts anti-atherogenic activity in disturbed flow-induced atherosclerosis by inhibiting ER stress and the inflammatory response. This study suggests that UDCA may be a therapeutic agent for prevention or treatment of atherosclerosis.
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Affiliation(s)
- Jihwa Chung
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710,
Korea
| | - Kyoung Hwa Kim
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710,
Korea
| | - Seok Cheol Lee
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710,
Korea
| | - Shung Hyun An
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710,
Korea
| | - Kihwan Kwon
- Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710,
Korea
- Department of Internal Medicine, Cardiology Division and GT5 Program of Ewha Womans University School of Medicine, Seoul 158-710,
Korea
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116
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Kohn JC, Zhou DW, Bordeleau F, Zhou AL, Mason BN, Mitchell MJ, King MR, Reinhart-King CA. Cooperative effects of matrix stiffness and fluid shear stress on endothelial cell behavior. Biophys J 2015; 108:471-8. [PMID: 25650915 DOI: 10.1016/j.bpj.2014.12.023] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 12/02/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022] Open
Abstract
Arterial hemodynamic shear stress and blood vessel stiffening both significantly influence the arterial endothelial cell (EC) phenotype and atherosclerosis progression, and both have been shown to signal through cell-matrix adhesions. However, the cooperative effects of fluid shear stress and matrix stiffness on ECs remain unknown. To investigate these cooperative effects, we cultured bovine aortic ECs on hydrogels matching the elasticity of the intima of compliant, young, or stiff, aging arteries. The cells were then exposed to laminar fluid shear stress of 12 dyn/cm(2). Cells grown on more compliant matrices displayed increased elongation and tighter EC-cell junctions. Notably, cells cultured on more compliant substrates also showed decreased RhoA activation under laminar shear stress. Additionally, endothelial nitric oxide synthase and extracellular signal-regulated kinase phosphorylation in response to fluid shear stress occurred more rapidly in ECs cultured on more compliant substrates, and nitric oxide production was enhanced. Together, our results demonstrate that a signaling cross talk between stiffness and fluid shear stress exists within the vascular microenvironment, and, importantly, matrices mimicking young and healthy blood vessels can promote and augment the atheroprotective signals induced by fluid shear stress. These data suggest that targeting intimal stiffening and/or the EC response to intima stiffening clinically may improve vascular health.
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Affiliation(s)
- Julie C Kohn
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Dennis W Zhou
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - François Bordeleau
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Allen L Zhou
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Brooke N Mason
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Michael J Mitchell
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Michael R King
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
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117
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Jeon BK, Kwon K, Kang JL, Choi YH. Csk-Induced Phosphorylation of Src at Tyrosine 530 is Essential for H2O2-Mediated Suppression of ERK1/2 in Human Umbilical Vein Endothelial Cells. Sci Rep 2015; 5:12725. [PMID: 26234813 PMCID: PMC4522603 DOI: 10.1038/srep12725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/06/2015] [Indexed: 02/07/2023] Open
Abstract
Mitogen-activated protein kinases (MAPKs) are key signal transducers involved in various cellular events such as growth, proliferation, and differentiation. Previous studies have reported that H2O2 leads to phosphorylation of extracellular signal-regulated kinase (ERK), one of the MAPKs in endothelial cells. The current study shows that H2O2 suppressed ERK1/2 activation and phosphorylation at specific concentrations and times in human umbilical vein endothelial cells but not in immortalized mouse aortic endothelial cells or human astrocytoma cell line CRT-MG. Phosphorylation of other MAPK family members (i.e., p38 and JNK) was not suppressed by H2O2. The decrease in ERK1/2 phosphorylation induced by H2O2 was inversely correlated with the level of phosphorylation of Src tyrosine 530. Using siRNA, it was found that H2O2-induced suppression of ERK1/2 was dependent on Csk. Physiological laminar flow abrogated, but oscillatory flow did not affect, the H2O2-induced suppression of ERK1/2 phosphorylation. In conclusion, H2O2-induced Csk translocation to the plasma membrane leads to phosphorylation of Src at the tyrosine 530 residue resulting in a reduction of ERK1/2 phosphorylation. Physiological laminar flow abrogates this effect of H2O2 by inducing phosphorylation of Src tyrosine 419. These findings broaden our understanding of signal transduction mechanisms in the endothelial cells against oxidative stress.
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Affiliation(s)
- Bo Kyung Jeon
- 1] Department of Physiology, School of Medicine, Ewha Womans University, Seoul, Korea [2] Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Kihwan Kwon
- Department of Internal Medicine, Division of Cardiology, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Jihee Lee Kang
- 1] Department of Physiology, School of Medicine, Ewha Womans University, Seoul, Korea [2] Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Youn-Hee Choi
- 1] Department of Physiology, School of Medicine, Ewha Womans University, Seoul, Korea [2] Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, Korea
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118
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"Do-it-yourself in vitro vasculature that recapitulates in vivo geometries for investigating endothelial-blood cell interactions". Sci Rep 2015. [PMID: 26202603 PMCID: PMC4894411 DOI: 10.1038/srep12401] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Investigating biophysical cellular interactions in the circulation currently requires choosing between in vivo models, which are difficult to interpret due in part to the hemodynamic and geometric complexities of the vasculature; or in vitro systems, which suffer from non-physiologic assumptions and/or require specialized microfabrication facilities and expertise. To bridge that gap, we developed an in vitro "do-it-yourself" perfusable vasculature model that recapitulates in vivo geometries, such as aneurysms, stenoses, and bifurcations, and supports endothelial cell culture. These inexpensive, disposable devices can be created rapidly (<2 hours) with high precision and repeatability, using standard off-the-shelf laboratory supplies. Using these "endothelialized" systems, we demonstrate that spatial variation in vascular cell adhesion molecule (VCAM-1) expression correlates with the wall shear stress patterns of vascular geometries. We further observe that the presence of endothelial cells in stenoses reduces platelet adhesion but increases sickle cell disease (SCD) red blood cell (RBC) adhesion in bifurcations. Overall, our method enables researchers from all disciplines to study cellular interactions in physiologically relevant, yet simple-to-make, in vitro vasculature models.
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119
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Controlled electromechanical cell stimulation on-a-chip. Sci Rep 2015; 5:11800. [PMID: 26135970 PMCID: PMC4488866 DOI: 10.1038/srep11800] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 05/28/2015] [Indexed: 12/15/2022] Open
Abstract
Stem cell research has yielded promising advances in regenerative medicine, but standard assays generally lack the ability to combine different cell stimulations with rapid sample processing and precise fluid control. In this work, we describe the design and fabrication of a micro-scale cell stimulator capable of simultaneously providing mechanical, electrical, and biochemical stimulation, and subsequently extracting detailed morphological and gene-expression analysis on the cellular response. This micro-device offers the opportunity to overcome previous limitations and recreate critical elements of the in vivo microenvironment in order to investigate cellular responses to three different stimulations. The platform was validated in experiments using human bone marrow mesenchymal stem cells. These experiments demonstrated the ability for inducing changes in cell morphology, cytoskeletal fiber orientation and changes in gene expression under physiological stimuli. This novel bioengineering approach can be readily applied to various studies, especially in the fields of stem cell biology and regenerative medicine.
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120
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Benam KH, Dauth S, Hassell B, Herland A, Jain A, Jang KJ, Karalis K, Kim HJ, MacQueen L, Mahmoodian R, Musah S, Torisawa YS, van der Meer AD, Villenave R, Yadid M, Parker KK, Ingber DE. Engineered in vitro disease models. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2015; 10:195-262. [PMID: 25621660 DOI: 10.1146/annurev-pathol-012414-040418] [Citation(s) in RCA: 355] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ultimate goal of most biomedical research is to gain greater insight into mechanisms of human disease or to develop new and improved therapies or diagnostics. Although great advances have been made in terms of developing disease models in animals, such as transgenic mice, many of these models fail to faithfully recapitulate the human condition. In addition, it is difficult to identify critical cellular and molecular contributors to disease or to vary them independently in whole-animal models. This challenge has attracted the interest of engineers, who have begun to collaborate with biologists to leverage recent advances in tissue engineering and microfabrication to develop novel in vitro models of disease. As these models are synthetic systems, specific molecular factors and individual cell types, including parenchymal cells, vascular cells, and immune cells, can be varied independently while simultaneously measuring system-level responses in real time. In this article, we provide some examples of these efforts, including engineered models of diseases of the heart, lung, intestine, liver, kidney, cartilage, skin and vascular, endocrine, musculoskeletal, and nervous systems, as well as models of infectious diseases and cancer. We also describe how engineered in vitro models can be combined with human inducible pluripotent stem cells to enable new insights into a broad variety of disease mechanisms, as well as provide a test bed for screening new therapies.
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Affiliation(s)
- Kambez H Benam
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts 02115;
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121
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Fulker D, Simmons A, Kabir K, Kark L, Barber T. The Hemodynamic Effects of Hemodialysis Needle Rotation and Orientation in an Idealized Computational Model. Artif Organs 2015; 40:185-9. [DOI: 10.1111/aor.12521] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- David Fulker
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney New South Wales Australia
| | - Anne Simmons
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney New South Wales Australia
| | - Kaveh Kabir
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney New South Wales Australia
| | - Lauren Kark
- Graduate School of Biomedical Engineering; University of New South Wales; Sydney New South Wales Australia
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering; University of New South Wales; Sydney New South Wales Australia
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122
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Chen CY, Cheng LY, Hsu CC, Mani K. Microscale flow propulsion through bioinspired and magnetically actuated artificial cilia. BIOMICROFLUIDICS 2015; 9:034105. [PMID: 26045730 PMCID: PMC4441715 DOI: 10.1063/1.4921427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/11/2015] [Indexed: 06/04/2023]
Abstract
Recent advances in microscale flow propulsion through bioinspired artificial cilia provide a promising alternative for lab-on-a-chip applications. However, the ability of actuating artificial cilia to achieve a time-dependent local flow control with high accuracy together with the elegance of full integration into the biocompatible microfluidic platforms remains remote. Driven by this motive, the current work has constructed a series of artificial cilia inside a microchannel to facilitate the time-dependent flow propulsion through artificial cilia actuation with high-speed (>40 Hz) circular beating behavior. The generated flow was quantified using micro-particle image velocimetry and particle tracking with instantaneous net flow velocity of up to 10(1 ) μm/s. Induced flow patterns caused by the tilted conical motion of artificial cilia constitutes efficient fluid propulsion at microscale. This flow phenomenon was further measured and illustrated by examining the induced flow behavior across the depth of the microchannel to provide a global view of the underlying flow propulsion mechanism. The presented analytic paradigms and substantial flow evidence present novel insights into the area of flow manipulation at microscale.
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Affiliation(s)
- Chia-Yuan Chen
- Department of Mechanical Engineering, National Cheng Kung University , Tainan 701, Taiwan
| | - Ling-Ying Cheng
- Department of Mechanical Engineering, National Cheng Kung University , Tainan 701, Taiwan
| | - Chun-Chieh Hsu
- Department of Mechanical Engineering, National Cheng Kung University , Tainan 701, Taiwan
| | - Karthick Mani
- Department of Mechanical Engineering, National Cheng Kung University , Tainan 701, Taiwan
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123
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Anderson DEJ, Glynn JJ, Song HK, Hinds MT. Engineering an endothelialized vascular graft: a rational approach to study design in a non-human primate model. PLoS One 2014; 9:e115163. [PMID: 25526637 PMCID: PMC4272299 DOI: 10.1371/journal.pone.0115163] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 11/19/2014] [Indexed: 12/14/2022] Open
Abstract
After many years of research, small diameter, synthetic vascular grafts still lack the necessary biologic integration to perform ideally in clinical settings. Endothelialization of vascular grafts has the potential to improve synthetic graft function, and endothelial outgrowth cells (EOCs) are a promising autologous cell source. Yet no work has established the link between endothelial cell functions and outcomes of implanted endothelialized grafts. This work utilized steady flow, oscillatory flow, and tumor necrosis factor stimulation to alter EOC phenotype and enable the formulation of a model to predict endothelialized graft performance. To accomplish this, EOC in vitro expression of coagulation and inflammatory markers was quantified. In parallel, in non-human primate (baboon) models, the platelet and fibrinogen accumulation on endothelialized grafts were quantified in an ex vivo shunt, or the tissue ingrowth on implanted grafts were characterized after 1mth. Oscillatory flow stimulation of EOCs increased in vitro coagulation markers and ex vivo platelet accumulation. Steady flow preconditioning did not affect platelet accumulation or intimal hyperplasia relative to static samples. To determine whether in vitro markers predict implant performance, a linear regression model of the in vitro data was fit to platelet accumulation data-correlating the markers with the thromboprotective performance of the EOCs. The model was tested against implant intimal hyperplasia data and found to correlate strongly with the parallel in vitro analyses. This research defines the effects of flow preconditioning on EOC regulation of coagulation in clinical vascular grafts through parallel in vitro, ex vivo, and in vivo analyses, and contributes to the translatability of in vitro tests to in vivo clinical graft performance.
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Affiliation(s)
- Deirdre E. J. Anderson
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States of America
| | - Jeremy J. Glynn
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States of America
| | - Howard K. Song
- Division of Cardiothoracic Surgery, Oregon Health & Science University, Portland, OR, United States of America
| | - Monica T. Hinds
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States of America
- * E-mail:
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124
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Ostrowski MA, Huang NF, Walker TW, Verwijlen T, Poplawski C, Khoo AS, Cooke JP, Fuller GG, Dunn AR. Microvascular endothelial cells migrate upstream and align against the shear stress field created by impinging flow. Biophys J 2014; 106:366-74. [PMID: 24461011 DOI: 10.1016/j.bpj.2013.11.4502] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/27/2013] [Accepted: 11/26/2013] [Indexed: 11/30/2022] Open
Abstract
At present, little is known about how endothelial cells respond to spatial variations in fluid shear stress such as those that occur locally during embryonic development, at heart valve leaflets, and at sites of aneurysm formation. We built an impinging flow device that exposes endothelial cells to gradients of shear stress. Using this device, we investigated the response of microvascular endothelial cells to shear-stress gradients that ranged from 0 to a peak shear stress of 9-210 dyn/cm(2). We observe that at high confluency, these cells migrate against the direction of fluid flow and concentrate in the region of maximum wall shear stress, whereas low-density microvascular endothelial cells that lack cell-cell contacts migrate in the flow direction. In addition, the cells align parallel to the flow at low wall shear stresses but orient perpendicularly to the flow direction above a critical threshold in local wall shear stress. Our observations suggest that endothelial cells are exquisitely sensitive to both magnitude and spatial gradients in wall shear stress. The impinging flow device provides a, to our knowledge, novel means to study endothelial cell migration and polarization in response to gradients in physical forces such as wall shear stress.
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Affiliation(s)
| | - Ngan F Huang
- Center for Tissue Regeneration, Repair and Restoration, Veterans Affairs Palo Alto Health Care System, Palo Alto, California; Stanford Cardiovascular Institute, Stanford University, Stanford, Califiornia; Division of Cardiovascular Medicine, Stanford University, Stanford, California
| | - Travis W Walker
- Chemical Engineering, Stanford University, Stanford, California
| | - Tom Verwijlen
- Department of Chemical Engineering, KU Leuven, Belgium
| | | | - Amanda S Khoo
- Division of Cardiovascular Medicine, Stanford University, Stanford, California
| | - John P Cooke
- Stanford Cardiovascular Institute, Stanford University, Stanford, Califiornia; Division of Cardiovascular Medicine, Stanford University, Stanford, California
| | - Gerald G Fuller
- Chemical Engineering, Stanford University, Stanford, California.
| | - Alexander R Dunn
- Chemical Engineering, Stanford University, Stanford, California; Stanford Cardiovascular Institute, Stanford University, Stanford, Califiornia.
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125
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Yu Q, Zhang Y, Xu CB. Apolipoprotein B, the villain in the drama? Eur J Pharmacol 2014; 748:166-9. [PMID: 25218904 DOI: 10.1016/j.ejphar.2014.08.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 08/18/2014] [Accepted: 08/20/2014] [Indexed: 12/31/2022]
Abstract
Low-density lipoprotein (LDL) is the major atherogenic lipoprotein and the primary target of lipid-lowering therapy for treating ischemic cardiovascular disease. Apolipoprotein B (apoB), an important structural component of LDL, plays a key role in cholesterol transport and removal in vascular wall. On the other hand, under pathological process, apoB interacts with the arterial wall to initiate the cascade of events that leads to atherosclerosis. However, interactions between apoB and vascular wall remain to be determined. Here, we address a pathological role of apoB per se and whole LDL particle in dysfunction of vascular endothelium and smooth muscle cells i.e. decreased endothelium-dependent vasodilation and increased receptor-mediated vasoconstriction. We intend to discuss: i) how apoB is responsible for the deleterious effects of LDL in the development of ischemic cardiovascular disease; ii) why vaccine based on peptides derived from apoB-100 is a promising therapy for treating ischemic cardiovascular disease, and iii) direct inhibition of apoB production should be a better therapeutic option than simple LDL-cholesterol lowering therapy in the patients with severe hypercholesterolemia at high cardiovascular risk with statin intolerance. In conclusion, apoB, but not cholesterol, plays a major role in LDL-induced dysfunction of endothelium, suggesting that direct apoB-targeting agents might be a promising therapy for the treatment of ischemic cardiovascular disease.
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Affiliation(s)
- Qi Yu
- Institute of Basic and Translational Medicine, Xi׳an Medical University, Shaanxi, Xi׳an 710021, PR China
| | - Yaping Zhang
- Institute of Basic and Translational Medicine, Xi׳an Medical University, Shaanxi, Xi׳an 710021, PR China; Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, BMC A13, SE-221 84 Lund, Sweden
| | - Cang-Bao Xu
- Institute of Basic and Translational Medicine, Xi׳an Medical University, Shaanxi, Xi׳an 710021, PR China; Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, BMC A13, SE-221 84 Lund, Sweden.
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126
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Kolluru GK, Majumder S, Chatterjee S. Rho-kinase as a therapeutic target in vascular diseases: striking nitric oxide signaling. Nitric Oxide 2014; 43:45-54. [PMID: 25196952 DOI: 10.1016/j.niox.2014.09.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 11/27/2022]
Abstract
Rho GTPases are a globular, monomeric group of small signaling G-protein molecules. Rho-associated protein kinase/Rho-kinase (ROCK) is a downstream effector protein of the Rho GTPase. Rho-kinases are the potential therapeutic targets in the treatment of cardiovascular diseases. Here, we have primarily discussed the intriguing roles of ROCK in cardiovascular health in relation to nitric oxide signaling. Further, we highlighted the biphasic effects of Y-27632, a ROCK inhibitor under shear stress, which acts as an agonist of nitric oxide production in endothelial cells. The biphasic effects of this inhibitor raised the question of safety of the drug usage in treating cardiovascular diseases.
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Affiliation(s)
| | - Syamantak Majumder
- Aab Cardiovascular Research Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Suvro Chatterjee
- Department of Biotechnology, Anna University, Chennai, India; Vascular Biology Lab, AU-KBC Research Centre, Anna University, Chennai, India.
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127
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Compton JL, Luo JC, Ma H, Botvinick E, Venugopalan V. High-throughput optical screening of cellular mechanotransduction. NATURE PHOTONICS 2014; 8:710-715. [PMID: 25309621 PMCID: PMC4189826 DOI: 10.1038/nphoton.2014.165] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 06/23/2014] [Indexed: 05/25/2023]
Abstract
We introduce an optical platform for rapid, high-throughput screening of exogenous molecules that affect cellular mechanotransduction. Our method initiates mechanotransduction in adherent cells using single laser-microbeam generated micro-cavitation bubbles (μCBs) without requiring flow chambers or microfluidics. These μCBs expose adherent cells to a microTsunami, a transient microscale burst of hydrodynamic shear stress, which stimulates cells over areas approaching 1mm2. We demonstrate microTsunami-initiated mechanosignalling in primary human endothelial cells. This observed signalling is consistent with G-protein-coupled receptor stimulation resulting in Ca2+ release by the endoplasmic reticulum. Moreover, we demonstrate the dose-dependent modulation of microTsunami-induced Ca2+ signalling by introducing a known inhibitor to this pathway. The imaging of Ca2+ signalling, and its modulation by exogenous molecules, demonstrates the capacity to initiate and assess cellular mechanosignalling in real-time. We utilize this capability to screen the effects of a set of small molecules on cellular mechanotransduction in 96-well plates using standard imaging cytometry.
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Affiliation(s)
- Jonathan L. Compton
- Department of Chemical Engineering and Materials Science, University of California, Irvine
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine
| | - Justin C. Luo
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine
- Department of Biomedical Engineering, University of California, Irvine
| | - Huan Ma
- Department of Chemical Engineering and Materials Science, University of California, Irvine
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine
| | - Elliot Botvinick
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine
- Department of Biomedical Engineering, University of California, Irvine
- Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine
| | - Vasan Venugopalan
- Department of Chemical Engineering and Materials Science, University of California, Irvine
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine
- Department of Biomedical Engineering, University of California, Irvine
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128
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Chistiakov DA, Sobenin IA, Orekhov AN, Bobryshev YV. Role of endoplasmic reticulum stress in atherosclerosis and diabetic macrovascular complications. BIOMED RESEARCH INTERNATIONAL 2014; 2014:610140. [PMID: 25061609 PMCID: PMC4100367 DOI: 10.1155/2014/610140] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 06/16/2014] [Indexed: 12/16/2022]
Abstract
Age-related changes in endoplasmic reticulum (ER) are associated with stress of this cell organelle. Unfolded protein response (UPR) is a normal physiological reaction of a cell in order to prevent accumulation of unfolded and misfolded proteins in the ER and improve the normal ER function. However, in pathologic conditions such as atherosclerosis, obesity, and diabetes, ER function becomes impaired, leading to the development of ER stress. In chronic ER stress, defective posttranslational protein folding results in deposits of aberrantly folded proteins in the ER and the induction of cell apoptosis mediated by UPR sensors C/EBPα-homologous protein (CHOP) and inositol requiring protein-1 (IRE1). Since ER stress and ER-induced cell death play a nonredundant role in the pathogenesis of atherosclerosis and diabetic macrovascular complications, pharmaceutical targeting of ER stress components and pathways may be beneficial in the treatment and prevention of cardiovascular pathology.
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Affiliation(s)
| | - Igor A. Sobenin
- Institute for Atherosclerosis, Skolkovo Innovation Center, Moscow, Russia
- Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia
- Russian Cardiology Research and Production Complex, Moscow, Russia
| | - Alexander N. Orekhov
- Institute for Atherosclerosis, Skolkovo Innovation Center, Moscow, Russia
- Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Yuri V. Bobryshev
- Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia
- Faculty of Medicine and St. Vincent's Centre for Applied Medical Research, University of New South Wales, Sydney, NSW 2052, Australia
- School of Medicine, University of Western Sydney, Campbelltown, NSW, Australia
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129
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Booth R, Noh S, Kim H. A multiple-channel, multiple-assay platform for characterization of full-range shear stress effects on vascular endothelial cells. LAB ON A CHIP 2014; 14:1880-90. [PMID: 24718713 DOI: 10.1039/c3lc51304a] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Vascular endothelial cells (VECs), which line blood vessels and are key to understanding pathologies and treatments of various diseases, experience highly variable wall shear stress (WSS) in vivo (1-60 dyn cm(-2)), imposing numerous effects on physiological and morphological functions. Previous flow-based systems for studying these effects have been limited in range, and comprehensive information on VEC functions at the full spectrum of WSS has not been available yet. To allow rapid characterization of WSS effects, we developed the first multiple channel microfluidic platform that enables a wide range (~15×) of homogeneous WSS conditions while simultaneously allowing trans-monolayer assays, such as permeability and trans-endothelial electrical resistance (TEER) assays, as well as cell morphometry and protein expression assays. Flow velocity/WSS distributions between channels were predicted with COMSOL simulations and verified by measurement using an integrated microflow sensor array. Biomechanical responses of the brain microvascular endothelial cell line bEnd.3 to the full natural spectrum of WSS were investigated with the platform. Under increasing WSS conditions ranging from 0 to 86 dyn cm(-2), (1) permeabilities of FITC-conjugated dextran and propidium iodide decreased, respectively, at rates of 4.06 × 10(-8) and 6.04 × 10(-8) cm s(-1) per dyn cm(-2); (2) TEER increased at a rate of 0.8 Ω cm(2) per dyn cm(-2); (3) increased alignment of cells along the flow direction under increasing WSS conditions; and finally (4) increased protein expression of both the tight junction component ZO-1 (~5×) and the efflux transporter P-gp (~6×) was observed at 86 dyn cm(-2) compared to static controls via western blot. We conclude that the presented microfluidic platform is a valid approach for comprehensively assaying cell responses to fluidic WSS.
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Affiliation(s)
- R Booth
- Department of Bioengineering, University of Utah, SMBB-3100, 36 S Wasatch Dr, Salt Lake City, UT 84112, USA.
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130
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Huang AH, Niklason LE. Engineering of arteries in vitro. Cell Mol Life Sci 2014; 71:2103-18. [PMID: 24399290 PMCID: PMC4024341 DOI: 10.1007/s00018-013-1546-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 12/17/2013] [Accepted: 12/18/2013] [Indexed: 12/20/2022]
Abstract
This review will focus on two elements that are essential for functional arterial regeneration in vitro: the mechanical environment and the bioreactors used for tissue growth. The importance of the mechanical environment to embryological development, vascular functionality, and vascular graft regeneration will be discussed. Bioreactors generate mechanical stimuli to simulate biomechanical environment of arterial system. This system has been used to reconstruct arterial grafts with appropriate mechanical strength for implantation by controlling the chemical and mechanical environments in which the grafts are grown. Bioreactors are powerful tools to study the effect of mechanical stimuli on extracellular matrix architecture and mechanical properties of engineered vessels. Hence, biomimetic systems enable us to optimize chemo-biomechanical culture conditions to regenerate engineered vessels with physiological properties similar to those of native arteries. In addition, this article reviews various bioreactors designed especially to apply axial loading to engineered arteries. This review will also introduce and examine different approaches and techniques that have been used to engineer biologically based vascular grafts, including collagen-based grafts, fibrin-gel grafts, cell sheet engineering, biodegradable polymers, and decellularization of native vessels.
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Affiliation(s)
- Angela H Huang
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06511, USA,
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131
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Ritschl LM, Fichter AM, von Düring M, Mitchell DA, Wolff KD, Mücke T. Introduction of a microsurgical in-vivo embolization-model in rats: the aorta-filter model. PLoS One 2014; 9:e89947. [PMID: 24587143 PMCID: PMC3935969 DOI: 10.1371/journal.pone.0089947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/24/2014] [Indexed: 11/28/2022] Open
Abstract
Vascular thrombosis with subsequent distal embolization remains a critical event for patients. Prevention of this life-threatening event can be achieved pharmacologically or mechanically with intravascular filter systems. The ability to evaluate the risk of embolization of certain techniques and procedures in vascular and microvascular surgery, such as, tissue glue or fibrin based haemostatic agents lacks convincing models. We performed 64 microvascular anastomoses in 44 rats, including 44 micro-pore polyurethane filter-anastomoses and 20 non-filter anastomoses. The rats were re-anesthetized and the aorta was re-exposed and removed four hours, three, seven, fourteen, thirty-one days, and six months postoperatively. The specimens were examined macro- and microscopically with regard to the appearance of the vessel wall, condition of the filter and the amount of thrombembolic material. Typical postoperative histopathological changes in vessel architecture were observed. Media necrosis was the first significant change three days postoperatively. Localized intimal hyperplasia, media necrosis, increase of media fibromyocytes and adventitial hypercellularity were seen to a significant extent at day seven postoperatively. Significant neovascularization of adventitia adjacent to the filter was seen after 14 days. A significant amount of thrombotic material was seen after four hours, three and 14 days interval. Only three intravascular filters became completely occluded (6.82%). The aorta-filter-anastomosis model appeared to be a valid in-vivo model in situations at risk for thrombembolic events, for microsurgical research and allowed sensitive analysis of surgical procedures and protection of the vascularized tissue. It may be suitable for a wide range of in-vivo microvascular experiments particularly in the rat model.
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Affiliation(s)
- Lucas M. Ritschl
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany
| | - Andreas M. Fichter
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany
| | | | - David A. Mitchell
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany
| | - Klaus-Dietrich Wolff
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany
| | - Thomas Mücke
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany
- * E-mail:
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132
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Experimental tools to monitor the dynamics of endothelial barrier function: a survey of in vitro approaches. Cell Tissue Res 2014; 355:485-514. [DOI: 10.1007/s00441-014-1810-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/13/2014] [Indexed: 02/05/2023]
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133
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Shav D, Gotlieb R, Zaretsky U, Elad D, Einav S. Wall shear stress effects on endothelial-endothelial and endothelial-smooth muscle cell interactions in tissue engineered models of the vascular wall. PLoS One 2014; 9:e88304. [PMID: 24520363 PMCID: PMC3919748 DOI: 10.1371/journal.pone.0088304] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 01/05/2014] [Indexed: 12/30/2022] Open
Abstract
Vascular functions are affected by wall shear stresses (WSS) applied on the endothelial cells (EC), as well as by the interactions of the EC with the adjacent smooth muscle cells (SMC). The present study was designed to investigate the effects of WSS on the endothelial interactions with its surroundings. For this purpose we developed and constructed two co-culture models of EC and SMC, and compared their response to that of a single monolayer of cultured EC. In one co-culture model the EC were cultured on the SMC, whereas in the other model the EC and SMC were cultured on the opposite sides of a membrane. We studied EC-matrix interactions through focal adhesion kinase morphology, EC-EC interactions through VE-Cadherin expression and morphology, and EC-SMC interactions through the expression of Cx43 and Cx37. In the absence of WSS the SMC presence reduced EC-EC connectivity but produced EC-SMC connections using both connexins. The exposure to WSS produced discontinuity in the EC-EC connections, with a weaker effect in the co-culture models. In the EC monolayer, WSS exposure (12 and 4 dyne/cm2 for 30 min) increased the EC-EC interaction using both connexins. WSS exposure of 12 dyne/cm2 did not affect the EC-SMC interactions, whereas WSS of 4 dyne/cm2 elevated the amount of Cx43 and reduced the amount of Cx37, with a different magnitude between the models. The reduced endothelium connectivity suggests that the presence of SMC reduces the sealing properties of the endothelium, showing a more inflammatory phenotype while the distance between the two cell types reduced their interactions. These results demonstrate that EC-SMC interactions affect EC phenotype and change the EC response to WSS. Furthermore, the interactions formed between the EC and SMC demonstrate that the 1-side model can simulate better the arterioles, while the 2-side model provides better simulation of larger arteries.
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Affiliation(s)
- Dalit Shav
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
| | - Ruth Gotlieb
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Uri Zaretsky
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - David Elad
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Shmuel Einav
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
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134
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Shen H, Tong S, Bao G, Wang B. Structural responses of cells to intracellular magnetic force induced by superparamagnetic iron oxide nanoparticles. Phys Chem Chem Phys 2014; 16:1914-20. [PMID: 24336693 PMCID: PMC4326048 DOI: 10.1039/c3cp51435h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we study the effects of intracellular force on human umbilical vein endothelial cells. We generated intracellular force on endothelial cells under different magnetic fields using the cell uptake of superparamagnetic iron oxide nanoparticles. Cell responses to intracellular force were observed using fluorescent microscopy. Our results indicated that nanoparticles were taken up by the cell by endocytosis and were deposited in lysosomes. Nanoparticles and lysosomes inside the cell could be relocated by the application of a magnetic force. The intracellular magnetic force could also be used to accelerate cell migration by adjusting the magnetic fields and giving the cell free culture space. No cytotoxicity of nanoparticles was found in our experiments. By comparing intracellular relocalization with migration of the whole cell, we obtained a better understanding of the self-defence mechanisms of cells based on their mechanical properties. Based on the promising mechanical properties and low cytotoxicity of our magnetic nanoparticles, their potential applications in cytomechanics and cell patterning are discussed.
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Affiliation(s)
- Han Shen
- State Key Laboratory of Optoelectronic Materials and Technologies, Micro & Nano Physics and Mechanics Research Laboratory, Sun Yat-sen University, Guangzhou, 510275, China
- Wallace H. Coulter Dept. of Biomedical Engineering, Georgia Institute of Technology, Atlanta, 30332, USA
| | - Sheng Tong
- Wallace H. Coulter Dept. of Biomedical Engineering, Georgia Institute of Technology, Atlanta, 30332, USA
| | - Gang Bao
- State Key Laboratory of Optoelectronic Materials and Technologies, Micro & Nano Physics and Mechanics Research Laboratory, Sun Yat-sen University, Guangzhou, 510275, China
- Wallace H. Coulter Dept. of Biomedical Engineering, Georgia Institute of Technology, Atlanta, 30332, USA
| | - Biao Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, Micro & Nano Physics and Mechanics Research Laboratory, Sun Yat-sen University, Guangzhou, 510275, China
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135
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Dixon AR, Rajan S, Kuo CH, Bersano T, Wold R, Futai N, Takayama S, Mehta G. Microfluidic device capable of medium recirculation for non-adherent cell culture. BIOMICROFLUIDICS 2014; 8:016503. [PMID: 24753733 PMCID: PMC3977789 DOI: 10.1063/1.4865855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 02/04/2014] [Indexed: 06/03/2023]
Abstract
We present a microfluidic device designed for maintenance and culture of non-adherent mammalian cells, which enables both recirculation and refreshing of medium, as well as easy harvesting of cells from the device. We demonstrate fabrication of a novel microfluidic device utilizing Braille perfusion for peristaltic fluid flow to enable switching between recirculation and refresh flow modes. Utilizing fluid flow simulations and the human promyelocytic leukemia cell line, HL-60, non-adherent cells, we demonstrate the utility of this RECIR-REFRESH device. With computer simulations, we profiled fluid flow and concentration gradients of autocrine factors and found that the geometry of the cell culture well plays a key role in cell entrapping and retaining autocrine and soluble factors. We subjected HL-60 cells, in the device, to a treatment regimen of 1.25% dimethylsulfoxide, every other day, to provoke differentiation and measured subsequent expression of CD11b on day 2 and day 4 and tumor necrosis factor-alpha (TNF-α) on day 4. Our findings display perfusion sensitive CD11b expression, but not TNF-α build-up, by day 4 of culture, with a 1:1 ratio of recirculation to refresh flow yielding the greatest increase in CD11b levels. RECIR-REFRESH facilitates programmable levels of cell differentiation in a HL-60 non-adherent cell population and can be expanded to other types of non-adherent cells such as hematopoietic stem cells.
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Affiliation(s)
- Angela R Dixon
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Shrinidhi Rajan
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chuan-Hsien Kuo
- Department of Mechanical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA ; Mobility and Thermal Management Department, General Dynamics Land Systems, Sterling Heights, Michigan 48310, USA
| | - Tom Bersano
- Google, Inc., 1600 Amphitheatre Parkway Mountain View, California 94043, USA ; University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA
| | - Rachel Wold
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Nobuyuki Futai
- Department of Mechanical Engineering, Shibaura Institute of Technology, 3-5-1 Toyosu, Koto-ku, Tokyo 135-8548, Japan
| | - Shuichi Takayama
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA ; Department of Macromolecular Science and Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Geeta Mehta
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA ; Department of Materials Science and Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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136
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Lu S, Wang Y. Single-cell imaging of mechanotransduction in endothelial cells. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:25-51. [PMID: 25081613 DOI: 10.1016/b978-0-12-394624-9.00002-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Endothelial cells (ECs) are constantly exposed to chemical and mechanical microenvironment in vivo. In mechanotransduction, cells can sense and translate the extracellular mechanical cues into intracellular biochemical signals, to regulate cellular processes. This regulation is crucial for many physiological functions, such as cell adhesion, migration, proliferation, and survival, as well as the progression of disease such as atherosclerosis. Here, we overview the current molecular understanding of mechanotransduction in ECs associated with atherosclerosis, especially those in response to physiological shear stress. The enabling technology of live-cell imaging has allowed the study of spatiotemporal molecular events and unprecedented understanding of intracellular signaling responses in mechanotransduction. Hence, we also introduce recent studies on mechanotransduction using single-cell imaging technologies.
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Affiliation(s)
- Shaoying Lu
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, USA
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, USA
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137
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Jia H, Caputo M, Ghorbel MT. Stem cells in vascular graft tissue engineering for congenital heart surgery. Interv Cardiol 2013. [DOI: 10.2217/ica.13.77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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138
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Cilla M, Peña E, Martínez MA. Mathematical modelling of atheroma plaque formation and development in coronary arteries. J R Soc Interface 2013; 11:20130866. [PMID: 24196695 DOI: 10.1098/rsif.2013.0866] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Atherosclerosis is a vascular disease caused by inflammation of the arterial wall, which results in the accumulation of low-density lipoprotein (LDL) cholesterol, monocytes, macrophages and fat-laden foam cells at the place of the inflammation. This process is commonly referred to as plaque formation. The evolution of the atherosclerosis disease, and in particular the influence of wall shear stress on the growth of atherosclerotic plaques, is still a poorly understood phenomenon. This work presents a mathematical model to reproduce atheroma plaque growth in coronary arteries. This model uses the Navier-Stokes equations and Darcy's law for fluid dynamics, convection-diffusion-reaction equations for modelling the mass balance in the lumen and intima, and the Kedem-Katchalsky equations for the interfacial coupling at membranes, i.e. endothelium. The volume flux and the solute flux across the interface between the fluid and the porous domains are governed by a three-pore model. The main species and substances which play a role in early atherosclerosis development have been considered in the model, i.e. LDL, oxidized LDL, monocytes, macrophages, foam cells, smooth muscle cells, cytokines and collagen. Furthermore, experimental data taken from the literature have been used in order to physiologically determine model parameters. The mathematical model has been implemented in a representative axisymmetric geometrical coronary artery model. The results show that the mathematical model is able to qualitatively capture the atheroma plaque development observed in the intima layer.
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Affiliation(s)
- Myriam Cilla
- Applied Mechanics and Bioengineering, Aragón Institute of Engineering Research (I3A), University of Zaragoza, , Zaragoza, Spain
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139
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Chalouhi N, Jabbour P, Magnotta V, Hasan D. Molecular imaging of cerebrovascular lesions. Transl Stroke Res 2013; 5:260-8. [PMID: 24323714 DOI: 10.1007/s12975-013-0291-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/23/2013] [Accepted: 09/26/2013] [Indexed: 01/19/2023]
Abstract
Inflammation is a key component in the pathogenesis of cerebrovascular lesions. Two agents have emerged as promising possibilities for imaging cerebrovascular lesions. These agents are ferumoxytol and myeloperoxidase (MPO)-specific paramagnetic magnetic resonance (MR) contrast agent. Ferumoxytol is an iron oxide nanoparticle coated by a carbohydrate shell that is used in MRI studies as an inflammatory marker as it is cleared by macrophages. Ferumoxytol-enhanced MRI allows noninvasive assessment of the inflammatory status of cerebral aneurysms and arteriovenous malformations and, possibly, may differentiate "unstable" lesions that require early intervention from "stable" lesions that can be safely observed. Several pilot studies have also suggested that MPO-specific paramagnetic MR contrast agent, di-5-hydroxytryptamide of gadopentetate dimeglumine, may allow imaging of inflammation in the wall of saccular aneurysms in animal models. However, studies in human subjects have yet to be performed. In this paper, we review current data regarding ferumoxytol-enhanced MRI and MPO-specific paramagnetic MR contrast agent and discuss current and future applications.
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Affiliation(s)
- Nohra Chalouhi
- Department of Neurosurgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, PA, USA
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140
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Mücke T, Ritschl LM, Balasso A, Wolff KD, Mitchell DA, Liepsch D. Opened end-to-side technique for end-to-side anastomosis and analyses by an elastic true-to-scale silicone rubber model. Microsurgery 2013; 34:28-36. [PMID: 24105681 DOI: 10.1002/micr.22182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 07/31/2013] [Accepted: 08/07/2013] [Indexed: 11/07/2022]
Abstract
The end-to-side anastomosis is frequently used in microvascular free flap transfer, but detailed rheological analyses are not available. The purpose of this study was to introduce a new modified end-to-side (Opened End-to-Side, OES-) technique and compare the resulting flow pattern to a conventional technique. The new technique was based on a bi-triangulated preparation of the branching-vessel end, resulting in a "fish-mouthed" opening. We performed two different types of end-to-side anastomoses in forty pig coronary arteries and produced one elastic, true-to-scale silicone rubber model of each anastomosis. Then we installed the transparent models in a circulatory experimental setup that simulated the physiological human blood flow. Flow velocity was measured with the one-component Laser-Doppler-Anemometer system, recording flow axial and perpendicular to the model at four defined cross-sections for seven heart cycles in each model. Maximal and minimal axial velocities ranged in the conventional model between 0.269 and -0.122 m/s and in the experimental model between 0.313 and -0.153 m/s. A less disturbed flow velocity distribution was seen in the experimental model distal to the anastomosis. The OES-technique showed superior flow profiles distal to the anastomosis with minor tendencies of flow separation and represents a new alternative for end-to-side anastomosis.
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Affiliation(s)
- Thomas Mücke
- Department of Oral and Maxillofacial Surgery, Technical University of Munich, Klinikum rechts der Isar, Germany
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141
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Dong J, Inthavong K, Tu J. Image-based computational hemodynamics evaluation of atherosclerotic carotid bifurcation models. Comput Biol Med 2013; 43:1353-62. [DOI: 10.1016/j.compbiomed.2013.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/14/2013] [Accepted: 06/19/2013] [Indexed: 11/15/2022]
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142
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Chalouhi N, Jabbour P, Magnotta V, Hasan D. The emerging role of ferumoxytol-enhanced MRI in the management of cerebrovascular lesions. Molecules 2013; 18:9670-83. [PMID: 23945642 PMCID: PMC6270297 DOI: 10.3390/molecules18089670] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/08/2013] [Indexed: 12/22/2022] Open
Abstract
Inflammation is increasingly being understood to be a key component to the pathophysiology of cerebrovascular lesions. Ferumoxytol, an iron oxide nanoparticle coated by a carbohydrate shell, has been used in MRI studies as an inflammatory marker because it is cleared by macrophages. Ferumoxytol-enhanced MRI has emerged as an important tool for noninvasive assessment of the inflammatory status of cerebrovascular lesions, namely aneurysms and arteriovenous malformations. Moreover, preliminary evidence suggests that ferumoxytol-enhanced MRI could be applied as a non-invasive tool to differentiate “unstable” lesions that require early intervention from “stable” lesions in which observation may be safe. Assessment of the effects of anti-inflammatory pharmacological interventions on cerebrovascular lesions is also a potentially crucial application of the technique. Future improvements in technique and MRI signal quantification will certainly pave the way for widespread and efficient use of ferumoxytol-enhanced MRI in clinical practice. In this paper, we review current data regarding ferumoxytol-enhanced MRI and discuss its current/potential applications and future perspectives.
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Affiliation(s)
- Nohra Chalouhi
- Department of Neurosurgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, PA 19107, USA; E-Mails: (N.C.); (P.J.)
| | - Pascal Jabbour
- Department of Neurosurgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, PA 19107, USA; E-Mails: (N.C.); (P.J.)
| | - Vincent Magnotta
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA; E-Mail:
| | - David Hasan
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-319-384-8669; Fax: +1-319-356-2237
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143
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Iwadate Y, Okimura C, Sato K, Nakashima Y, Tsujioka M, Minami K. Myosin-II-mediated directional migration of Dictyostelium cells in response to cyclic stretching of substratum. Biophys J 2013; 104:748-58. [PMID: 23442953 DOI: 10.1016/j.bpj.2013.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 01/03/2013] [Accepted: 01/07/2013] [Indexed: 11/29/2022] Open
Abstract
Living cells are constantly subjected to various mechanical stimulations, such as shear flow, osmotic pressure, and hardness of substratum. They must sense the mechanical aspects of their environment and respond appropriately for proper cell function. Cells adhering to substrata must receive and respond to mechanical stimuli from the substrata to decide their shape and/or migrating direction. In response to cyclic stretching of the elastic substratum, intracellular stress fibers in fibroblasts and endothelial, osteosarcoma, and smooth muscle cells are rearranged perpendicular to the stretching direction, and the shape of those cells becomes extended in this new direction. In the case of migrating Dictyostelium cells, cyclic stretching regulates the direction of migration, and not the shape, of the cell. The cells migrate in a direction perpendicular to that of the stretching. However, the molecular mechanisms that induce the directional migration remain unknown. Here, using a microstretching device, we recorded green fluorescent protein (GFP)-myosin-II dynamics in Dictyostelium cells on an elastic substratum under cyclic stretching. Repeated stretching induced myosin II localization equally on both stretching sides in the cells. Although myosin-II-null cells migrated randomly, myosin-II-null cells expressing a variant of myosin II that cannot hydrolyze ATP migrated perpendicular to the stretching. These results indicate that Dictyostelium cells accumulate myosin II at the portion of the cell where a large strain is received and migrate in a direction other than that of the portion where myosin II accumulated. This polarity generation for migration does not require the contraction of actomyosin.
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Affiliation(s)
- Yoshiaki Iwadate
- Department of Functional Molecular Biology, Graduate School of Medicine, Yamaguchi University, Yamaguchi, Japan.
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144
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Zhang J, Friedman MH. Adaptive response of vascular endothelial cells to an acute increase in shear stress frequency. Am J Physiol Heart Circ Physiol 2013; 305:H894-902. [PMID: 23851277 DOI: 10.1152/ajpheart.00174.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Local shear stress sensed by arterial endothelial cells is occasionally altered by changes in global hemodynamic parameters, e.g., heart rate and blood flow rate, as a result of normal physiological events, such as exercise. In a recently study (41), we demonstrated that during the adaptive response to increased shear magnitude, porcine endothelial cells exhibited an unique phenotype featuring a transient increase in permeability and the upregulation of a set of anti-inflammatory and antioxidative genes. In the present study, we characterize the adaptive response of these cells to an increase in shear frequency, another important hemodynamic parameter with implications in atherogenesis. Endothelial cells were preconditioned by a basal-level sinusoidal shear stress of 15 ± 15 dyn/cm(2) at 1 Hz, and the frequency was then elevated to 2 Hz. Endothelial permeability increased slowly after the frequency step-up, but the increase was relatively small. Using microarrays, we identified 37 genes that are sensitive to the frequency step-up. The acute increase in shear frequency upregulates a set of cell-cycle regulation and angiogenesis-related genes. The overall adaptive response to the increased frequency is distinctly different from that to a magnitude step-up. However, consistent with the previous study, our data support the notion that endothelial function during an adaptive response is different than that of fully adapted endothelial cells. Our studies may also provide insights into the beneficial effects of exercise on vascular health: transient increases in frequency may facilitate endothelial repair, whereas similar increases in shear magnitude may keep excessive inflammation and oxidative stress at bay.
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Affiliation(s)
- Ji Zhang
- Department of Biomedical Engineering, Duke University, Durham, North Carolina; and
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145
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Ruzevick J, Jackson C, Pradilla G, Garzon-Muvdi T, Tamargo RJ. Aneurysm formation in proinflammatory, transgenic haptoglobin 2-2 mice. Neurosurgery 2013; 72:70-6; discussion 76. [PMID: 23096414 DOI: 10.1227/neu.0b013e318276b306] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Inflammation and macrophages in particular are believed to play a role in aneurysm formation. The haptoglobin (Hp) 2-2 genotype is associated with a proinflammatory state. OBJECTIVE To investigate the role of inflammation in the formation of aneurysms using a murine model of aneurysm formation in transgenic, proinflammatory Hp2-2 mice and wild-type Hp1-1 mice. METHODS Carotid artery aneurysms were induced in the left common carotid artery of wild-type Hp1-1 mice and transgenic Hp2-2 mice using elastase to degrade the arterial wall of the common carotid artery and angiotensin II to induce hypertension. There were 4 experimental groups: (1) sham surgery (n = 11); (2) angiotensin II only (n = 10); (3) elastase only (n = 20); and (4) elastase + angiotensin II (n = 20). Aneurysm size was determined by measuring the outer circumference and luminal circumference of the blood vessel. Macrophages that infiltrated the aneurysm wall were quantified by immunohistochemistry. Results were analyzed using 2-way analysis of variance with a Bonferroni post-test. RESULTS Aneurysms in Hp2-2 mice were significantly larger than aneurysms in Hp1-1 mice in the setting of vessel wall degradation and hypertension (P = .02 for outer circumference, P = .01 for luminal circumference). Furthermore, the number of macrophages infiltrating the aneurysm wall was significantly increased in Hp2-2 mice (P < .001). CONCLUSION Hp2-2 mice formed aneurysms that were significantly larger and had a significantly greater number of macrophages in the aneurysm wall compared with Hp1-1 mice. This suggests that the proinflammatory state associated with the Hp2-2 protein is involved in aneurysm formation and that the Hp genotype may be a useful biomarker in predicting aneurysm progression.
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Affiliation(s)
- Jacob Ruzevick
- Department of Neurological Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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146
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Kheyfets VO, O'Dell W, Smith T, Reilly JJ, Finol EA. Considerations for numerical modeling of the pulmonary circulation--a review with a focus on pulmonary hypertension. J Biomech Eng 2013; 135:61011-15. [PMID: 23699723 PMCID: PMC3705788 DOI: 10.1115/1.4024141] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 03/25/2013] [Accepted: 04/04/2013] [Indexed: 12/12/2022]
Abstract
Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions between blood vessels, blood flow, and the heart. Moreover, metrics that can only be predicted with computational simulations (e.g., mechanical wall stress, oscillatory shear index, etc.) can be used to assess disease progression, for presurgical planning, and for interventional outcomes. Because the pulmonary vasculature is susceptible to a wide range of pathologies that directly impact and are affected by the hemodynamics (e.g., pulmonary hypertension), the ability to develop numerical models of pulmonary blood flow can be invaluable to the clinical scientist. Pulmonary hypertension is a devastating disease that can directly benefit from computational hemodynamics when used for diagnosis and basic research. In the present work, we provide a clinical overview of pulmonary hypertension with a focus on the hemodynamics, current treatments, and their limitations. Even with a rich history in computational modeling of the human circulation, hemodynamics in the pulmonary vasculature remains largely unexplored. Thus, we review the tasks involved in developing a computational model of pulmonary blood flow, namely vasculature reconstruction, meshing, and boundary conditions. We also address how inconsistencies between models can result in drastically different flow solutions and suggest avenues for future research opportunities. In its current state, the interpretation of this modeling technology can be subjective in a research environment and impractical for clinical practice. Therefore, considerations must be taken into account to make modeling reliable and reproducible in a laboratory setting and amenable to the vascular clinic. Finally, we discuss relevant existing models and how they have been used to gain insight into cardiopulmonary physiology and pathology.
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Affiliation(s)
- V. O. Kheyfets
- Department of Biomedical Engineering,The University of Texas at San Antonio,AET 1.360, One UTSA Circle,San Antonio, TX 78249
| | - W. O'Dell
- Department of Radiation Oncology,University of Florida,Shands Cancer Center,P.O. Box 100385,2033 Mowry Road,Gainesville, FL 32610
| | - T. Smith
- Western Allegheny Health System,Allegheny General Hospital,Gerald McGinnis Cardiovascular Institute,320 East North Avenue,Pittsburgh, PA 15212
| | - J. J. Reilly
- Department of Medicine,The University of Pittsburgh,1218 Scaife Hall,3550 Terrace Street,Pittsburgh, PA 15261
| | - E. A. Finol
- Department of Biomedical Engineering,The University of Texas at San Antonio,AET 1.360, One UTSA Circle,San Antonio, TX 78249e-mail:
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147
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Puzserova A, Slezak P, Balis P, Bernatova I. Long-term social stress induces nitric oxide-independent endothelial dysfunction in normotensive rats. Stress 2013; 16:331-9. [PMID: 22928844 DOI: 10.3109/10253890.2012.725116] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
As chronic stress is a significant risk factor for several cardiovascular disorders, this study investigated the hypothesis that long-term stress produced by crowding may lead to alterations in nitric oxide (NO) production and NO-dependent relaxation in the course of stress, resulting in endothelial dysfunction and hypertension in Wistar-Kyoto (WKY) rats. For this purpose, male WKY rats were divided into control (480 cm2/rat, four rats/cage, n = 8) and crowded (200 cm2/rat, five rats/cage, n = 10) groups for 8 or 12 weeks. Vasorelaxation was evaluated in vitro as a response to acetylcholine (ACh) of femoral arteries pre-contracted by serotonin, before and after NO synthase inhibition (N (G)-nitro-l-arginine methyl ester, 300 μmol/l). Crowding increased plasma corticosterone concentration but failed to affect blood pressure (determined by tail-cuff plethysmography) of rats. NO production was unchanged in the hypothalamus and left ventricle of both stressed groups; however it was significantly elevated in the aorta. Maximal ACh-induced relaxation was elevated significantly after 8-week stress, but reduced after 12 weeks. Stress elevated the NO-dependent component and reduced the NO-independent component of ACh-induced relaxation in both crowded groups. However, a reduction in the NO-independent component was more pronounced after 12-week versus 8-week stress. In conclusion, elevated endothelium-dependent relaxation was observed after 8-week stress, while the extension of stress exposure resulted in a reduction in arterial relaxation associated with a more pronounced decrease of its NO-independent component. Thus, elevation of the NO-dependent component of relaxation can be considered as an adaptation mechanism, and impairment of NO-independent relaxation might be the initial step in chronic stress-induced cardiovascular disorders.
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Affiliation(s)
- Angelika Puzserova
- Institute of Normal and Pathological Physiology, Centre of Excellence for Examination of Regulatory Role of Nitric Oxide in Civilisation Diseases, Slovak Academy of Sciences, Bratislava, Slovak Republic
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148
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Kunes P, Mandak J, Holubcova Z, Kolackova M, Krejsek J. The long pentraxin PTX3: a candidate anti-inflammatory mediator in cardiac surgery. Perfusion 2013; 28:377-89. [DOI: 10.1177/0267659113483799] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Coronary artery bypass grafting (CABG) is performed with the use of cardiopulmonary bypass (CPB) and cardioplegic arrest (CA) of the heart. The advantage of this technique, alternatively referred to as “on-pump” surgery, resides, for the surgeon, in relatively easy access to and manipulation with the non-beating, bloodless heart. However, the advantage that is, thereby, gained by the patient is paid off by an increased susceptibility to postoperative systemic inflammatory response syndrome (SIRS). Under unfavorable conditions, the inflammatory syndrome may develop into life-threatening forms of MODS (multiple organ dysfunction syndrome) or even MOFS (multiple organ failure syndrome). Deliberate avoidance of CPB, also known as “off-pump” surgery, attenuates early postoperative inflammation throughout its trajectory of SIRS→MODS→MOFS, but, in the long run, there appears to be no substantial difference in the overall mortality rates. In the last years, our knowledge of the pathophysiology of surgical inflammation has increased considerably. Recent findings, highlighting the as yet rather obscure role of pentraxin 3 (PTX3) in these processes, are discussed in this review article.
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Affiliation(s)
- P Kunes
- Deparment of Cardiac Surgery, Charles University in Prague, Medical School and University Hospital in Hradec Kralove, Czech Republic
| | - J Mandak
- Deparment of Cardiac Surgery, Charles University in Prague, Medical School and University Hospital in Hradec Kralove, Czech Republic
| | - Z Holubcova
- Deparment of Cardiac Surgery, Charles University in Prague, Medical School and University Hospital in Hradec Kralove, Czech Republic
| | - M Kolackova
- Department of Clinical Immunology, Charles University in Prague, Medical School and University Hospital in Hradec Kralove, Czech Republic
| | - J Krejsek
- Department of Clinical Immunology, Charles University in Prague, Medical School and University Hospital in Hradec Kralove, Czech Republic
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149
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Huang NF, Lai ES, Ribeiro AJS, Pan S, Pruitt BL, Fuller GG, Cooke JP. Spatial patterning of endothelium modulates cell morphology, adhesiveness and transcriptional signature. Biomaterials 2013; 34:2928-37. [PMID: 23357369 PMCID: PMC3581686 DOI: 10.1016/j.biomaterials.2013.01.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/04/2013] [Indexed: 01/08/2023]
Abstract
Microscale and nanoscale structures can spatially pattern endothelial cells (ECs) into parallel-aligned organization, mimicking their cellular alignment in blood vessels exposed to laminar shear stress. However, the effects of spatial patterning on the function and global transcriptome of ECs are incompletely characterized. We used both parallel-aligned micropatterned and nanopatterned biomaterials to evaluate the effects of spatial patterning on the phenotype of ECs, based on gene expression profiling, functional characterization of monocyte adhesion, and quantification of cellular morphology. We demonstrate that both micropatterned and aligned nanofibrillar biomaterials could effectively guide EC organization along the direction of the micropatterned channels or nanofibrils, respectively. The ability of ECs to sense spatial patterning cues were abrogated in the presence of cytoskeletal disruption agents. Moreover, both micropatterned and aligned nanofibrillar substrates promoted an athero-resistant EC phenotype by reducing endothelial adhesiveness for monocytes and platelets, as well as by downregulating the expression of adhesion proteins and chemokines. We further found that micropatterned ECs have a transcriptional signature that is unique from non-patterned ECs, as well as from ECs aligned by shear stress. These findings highlight the importance of spatial patterning cues in guiding EC organization and function, which may have clinical relevance in the development of vascular grafts that promote patency.
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Affiliation(s)
- Ngan F Huang
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA 94305, USA
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150
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Karimi S, Dadvar M, Modarress H, Dabir B. A new correlation for inclusion of leaky junctions in macroscopic modeling of atherosclerotic lesion initiation. J Theor Biol 2013; 329:94-100. [PMID: 23507340 DOI: 10.1016/j.jtbi.2013.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 02/11/2013] [Accepted: 02/27/2013] [Indexed: 01/17/2023]
Abstract
Vascular endothelium cells are the main barriers between vessel wall and blood flow; they play an essential role in the progression of atherosclerosis. Various experimental and computational studies have been carried out to identify the pathways and mechanisms by which Low Density Lipoprotein (LDL) transfers through the endothelium cells. The most conventional hypothesis in LDL transfer is the presence of leaky junctions. Leaky junctions are large pores in endothelium cells associated with cell mitosis or apoptosis. Although some studies have microscopically modeled leaky junctions, none however have evaluated their effects in a macroscopic level modeling. In this study, a new approach is proposed to consider the presence of the leaky junction as the main pathway in LDL transport from the lumen into the arterial wall. LDL transport in macroscopic scale is simulated in a simplified axisymmetric model and Staverman filtration coefficient (SFC) is used as a measurement criterion for estimating the amount of leaky junctions. According to the results, decreasing SFC corresponds to decreasing the resistance of endothelium cells. In other words, an increase in the number of leaky junctions causes an increase in the LDL concentration inside the arterial wall. Additionally, a new correlation is presented for evaluating the fraction of leaky junctions in the endothelial cells by comparing the results of macroscopic and microscopic models. This correlation accredits each SFC to a specified fraction of leaky junction in the endothelial cells. Therefore, it can be used for the inclusion of leaky junctions in the macroscopic modeling without incorporating any of the complications that are raised by the microscopic modeling studies. This correlation has important implications in the modeling of the atherosclerosis lesions propagation.
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Affiliation(s)
- Safoora Karimi
- Department of Chemical Engineering, Jundi-Shapur University of Technology, Dezful, Iran
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