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Chong DST, Turner LA, Gadegaard N, Seifalian AM, Dalby MJ, Hamilton G. Nanotopography and plasma treatment: redesigning the surface for vascular graft endothelialisation. Eur J Vasc Endovasc Surg 2015; 49:335-43. [PMID: 25579872 DOI: 10.1016/j.ejvs.2014.12.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 12/05/2014] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Vascular graft materials in clinical use, such as polytetrafluoroethylene (PTFE) and Dacron, do not endothelialise and have low patency rates. The importance of an endothelial cell layer on the luminal surface of a vascular graft is well-known with surface topography and chemistry playing an important role. The aim of this study was to investigate the potential of plasma treatment and topographical structures on the luminal graft surface to enhance the self-endothelialisation potential of a nanocomposite vascular graft. METHODS POSS-PCU is a polycarbonate urea urethane (PCU) with a nanoparticle, polyhedral oligomeric silsesquioxane (POSS) incorporated within it. Planar, microgrooved, and nanopit patterned polymer films were fabricated using photolithography, electron beam lithography, reactive ion etching, and replication by solvent casting. Films were then exposed to oxygen plasma treatment at different powers for a fixed time (40 W, 60 W, 80 W/60 seconds). Effects of plasma treatment were assessed using scanning electron microscopy, atomic force microscopy and water contact angle analysis. Human umbilical vein endothelial cell (HUVEC) proliferation and morphology were characterised using immunostaining, live/dead staining, and Coomassie blue staining. RESULTS Successful embossing of the micro- and nanostructures was confirmed. Oxygen plasma treatment of the different samples showed that increasing power significantly increased the hydrophilicity of the samples (p < .0001). Improved HUVEC adhesion was seen on plasma modified compared with untreated samples (p < .0001). Coomassie blue staining showed that after 5 days, cells started to form monolayers and live/dead staining showed the cells were viable. Immunostaining showed that HUVECs expressed nitric oxide synthase on all topographies with focal adhesions appearing more pronounced on nanopit surfaces, showing retention of morphology and function. CONCLUSION These encouraging results indicate a future important role for plasma treatment and nanotopography in the development of endothelialised vascular grafts.
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Affiliation(s)
- D S T Chong
- Department of Vascular Surgery, Royal Free London NHS Foundation Trust, UK; Division of Surgery and Interventional Science, UCL, UK
| | - L A Turner
- Centre for Cell Engineering, University of Glasgow, UK
| | - N Gadegaard
- Division of Biomedical Engineering, University of Glasgow, UK
| | - A M Seifalian
- Division of Surgery and Interventional Science, UCL, UK
| | - M J Dalby
- Centre for Cell Engineering, University of Glasgow, UK
| | - G Hamilton
- Department of Vascular Surgery, Royal Free London NHS Foundation Trust, UK; Division of Surgery and Interventional Science, UCL, UK.
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Goh ET, Wong E, Farhatnia Y, Tan A, Seifalian AM. Accelerating in situ endothelialisation of cardiovascular bypass grafts. Int J Mol Sci 2014; 16:597-627. [PMID: 25551605 PMCID: PMC4307264 DOI: 10.3390/ijms16010597] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 12/19/2014] [Indexed: 12/18/2022] Open
Abstract
The patency of synthetic cardiovascular grafts in the long run is synonymous with their ability to inhibit the processes of intimal hyperplasia, thrombosis and calcification. In the human body, the endothelium of blood vessels exhibits characteristics that inhibit such processes. As such it is not surprising that research in tissue engineering is directed towards replicating the functionality of the natural endothelium in cardiovascular grafts. This can be done either by seeding the endothelium within the lumen of the grafts prior to implantation or by designing the graft such that in situ endothelialisation takes place after implantation. Due to certain difficulties identified with in vitro endothelialisation, in situ endothelialisation, which will be the focus of this article, has garnered interest in the last years. To promote in situ endothelialisation, the following aspects can be taken into account: (1) Endothelial progenital cell mobilization, adhesion and proliferation; (2) Regulating differentiation of progenitor cells to mature endothelium; (3) Preventing thrombogenesis and inflammation during endothelialisation. This article aims to review and compile recent developments to promote the in situ endothelialisation of cardiovascular grafts and subsequently improve their patency, which can also have widespread implications in the field of tissue engineering.
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Affiliation(s)
- Ee Teng Goh
- Centre for Nanotechnology & Regenerative Medicine, Research Department of Nanotechnology, UCL Division of Surgery & Interventional Science, University College London (UCL), London NW3 2QG, UK.
| | - Eleanor Wong
- Centre for Nanotechnology & Regenerative Medicine, Research Department of Nanotechnology, UCL Division of Surgery & Interventional Science, University College London (UCL), London NW3 2QG, UK.
| | - Yasmin Farhatnia
- Centre for Nanotechnology & Regenerative Medicine, Research Department of Nanotechnology, UCL Division of Surgery & Interventional Science, University College London (UCL), London NW3 2QG, UK.
| | - Aaron Tan
- Centre for Nanotechnology & Regenerative Medicine, Research Department of Nanotechnology, UCL Division of Surgery & Interventional Science, University College London (UCL), London NW3 2QG, UK.
| | - Alexander M Seifalian
- Centre for Nanotechnology & Regenerative Medicine, Research Department of Nanotechnology, UCL Division of Surgery & Interventional Science, University College London (UCL), London NW3 2QG, UK.
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Charras G, Sahai E. Physical influences of the extracellular environment on cell migration. Nat Rev Mol Cell Biol 2014; 15:813-24. [PMID: 25355506 DOI: 10.1038/nrm3897] [Citation(s) in RCA: 466] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The way in which a cell migrates is influenced by the physical properties of its surroundings, in particular the properties of the extracellular matrix. How the physical aspects of the cell's environment affect cell migration poses a considerable challenge when trying to understand migration in complex tissue environments and hinders the extrapolation of in vitro analyses to in vivo situations. A comprehensive understanding of these problems requires an integrated biochemical and biophysical approach. In this Review, we outline the findings that have emerged from approaches that span these disciplines, with a focus on actin-based cell migration in environments with different stiffness, dimensionality and geometry.
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Affiliation(s)
- Guillaume Charras
- 1] London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, UK. [2] Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Erik Sahai
- Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
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Vandrangi P, Gott SC, Kozaka R, Rodgers VGJ, Rao MP. Comparative endothelial cell response on topographically patterned titanium and silicon substrates with micrometer to sub-micrometer feature sizes. PLoS One 2014; 9:e111465. [PMID: 25357245 PMCID: PMC4214724 DOI: 10.1371/journal.pone.0111465] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/02/2014] [Indexed: 12/02/2022] Open
Abstract
In this work, we evaluate the in vitro response of endothelial cells (EC) to variation in precisely-defined, micrometer to sub-micrometer scale topography on two different substrate materials, titanium (Ti) and silicon (Si). Both substrates possess identically-patterned surfaces composed of microfabricated, groove-based gratings with groove widths ranging from 0.5 to 50 µm, grating pitch twice the groove width, and groove depth of 1.3 µm. These specific materials are chosen due to their relevance for implantable microdevice applications, while grating-based patterns are chosen for the potential they afford for inducing elongated and aligned cellular morphologies reminiscent of the native endothelium. Using EA926 cells, a human EC variant, we show significant improvement in cellular adhesion, proliferation, morphology, and function with decreasing feature size on patterned Ti substrates. Moreover, we show similar trending on patterned Si substrates, albeit to a lesser extent than on comparably patterned Ti substrates. Collectively, these results suggest promise for sub-micrometer topographic patterning in general, and sub-micrometer patterning of Ti specifically, as a means for enhancing endothelialization and neovascularisation for novel implantable microdevice applications.
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Affiliation(s)
- Prashanthi Vandrangi
- Department of Mechanical Engineering, University of California Riverside, Riverside, California, United States of America
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Shannon C. Gott
- Department of Mechanical Engineering, University of California Riverside, Riverside, California, United States of America
| | - Ryan Kozaka
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Victor G. J. Rodgers
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
- Materials Science and Engineering Program, University of California Riverside, Riverside, California, United States of America
| | - Masaru P. Rao
- Department of Mechanical Engineering, University of California Riverside, Riverside, California, United States of America
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
- Materials Science and Engineering Program, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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Guiding the behaviors of human umbilical vein endothelial cells with patterned silk fibroin films. Colloids Surf B Biointerfaces 2014; 122:79-84. [PMID: 25016547 DOI: 10.1016/j.colsurfb.2014.06.049] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 11/23/2022]
Abstract
Silk fibroin is an ideal blood vessel substitute due to its advantageous qualities including variable size, good suture retention, low thrombogenicity, non-toxicity, non-immunogenicity, biocompatibility, and controllable biodegradation. In this study, silk fibroin films with a variety of surface patterns (e.g. square wells, round wells plus square pillars, square pillars, and gratings) were prepared for in vitro characterization of human umbilical vein endothelial cell's (HUVEC) response. The affects of biomimetic length-scale topographic cues on the cell orientation/elongation, proliferation, and cell-substrate interactions have been investigated. The density of cells is significantly decreased in response to the grating patterns (70±3nm depth, 600±8nm pitch) and the square pillars (333±42nm gap). Most notably, we observed the contact guidance response of filopodia of cells cultured on the surface of round wells plus square pillars. Overall, our data demonstrates that the patterned silk fibroin films have an impact on the behaviors of human umbilical vein endothelial cells.
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Luminal Surface Engineering, ‘Micro and Nanopatterning’: Potential for Self Endothelialising Vascular Grafts? Eur J Vasc Endovasc Surg 2014; 47:566-76. [DOI: 10.1016/j.ejvs.2014.02.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 02/11/2014] [Indexed: 11/19/2022]
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Raghunathan V, McKee C, Cheung W, Naik R, Nealey PF, Russell P, Murphy CJ. Influence of extracellular matrix proteins and substratum topography on corneal epithelial cell alignment and migration. Tissue Eng Part A 2014; 19:1713-22. [PMID: 23488816 DOI: 10.1089/ten.tea.2012.0584] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The basement membrane (BM) of the corneal epithelium presents biophysical cues in the form of topography and compliance that can impact the phenotype and behaviors of cells and their nuclei through modulation of cytoskeletal dynamics. In addition, it is also well known that the intrinsic biochemical attributes of BMs can modulate cell behaviors. In this study, the influence of the combination of exogenous coating of extracellular matrix proteins (ECM) (fibronectin-collagen [FNC]) with substratum topography was investigated on cytoskeletal architecture as well as alignment and migration of immortalized corneal epithelial cells. In the absence of FNC coating, a significantly greater percentage of cells aligned parallel with the long axis of the underlying anisotropically ordered topographic features; however, their ability to migrate was impaired. Additionally, changes in the surface area, elongation, and orientation of cytoskeletal elements were differentially influenced by the presence or absence of FNC. These results suggest that the effects of topographic cues on cells are modulated by the presence of surface-associated ECM proteins. These findings have relevance to experiments using cell cultureware with biomimetic biophysical attributes as well as the integration of biophysical cues in tissue-engineering strategies and the development of improved prosthetics.
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Affiliation(s)
- Vijaykrishna Raghunathan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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59
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Morgan JT, Murphy CJ, Russell P. What do mechanotransduction, Hippo, Wnt, and TGFβ have in common? YAP and TAZ as key orchestrating molecules in ocular health and disease. Exp Eye Res 2013; 115:1-12. [PMID: 23792172 DOI: 10.1016/j.exer.2013.06.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/03/2013] [Accepted: 06/10/2013] [Indexed: 01/09/2023]
Abstract
Cells in vivo are exposed to a complex signaling environment. Biochemical signaling modalities, such as secreted proteins, specific extracellular matrix domains and ion fluxes certainly compose an important set of regulatory signals to cells. However, these signals are not exerted in isolation, but rather in concert with biophysical cues of the surrounding tissue, such as stiffness and topography. In this review, we attempt to highlight the biophysical attributes of ocular tissues and their influence on cellular behavior. Additionally, we introduce the proteins YAP and TAZ as targets of biophysical and biochemical signaling and important agonists and antagonists of numerous signaling pathways, including TGFβ and Wnt. We frame the discussion around this extensive signaling crosstalk, which allows YAP and TAZ to act as orchestrating molecules, capable of integrating biophysical and biochemical cues into a broad cellular response. Finally, while we draw on research from various fields to provide a full picture of YAP and TAZ, we attempt to highlight the intersections with vision science and the exciting work that has already been performed.
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Affiliation(s)
- Joshua T Morgan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, 1 Shields Ave., Davis, CA 95616, USA
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60
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Dreier B, Gasiorowski JZ, Morgan JT, Nealey PF, Russell P, Murphy CJ. Early responses of vascular endothelial cells to topographic cues. Am J Physiol Cell Physiol 2013; 305:C290-8. [PMID: 23703527 DOI: 10.1152/ajpcell.00264.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular endothelial cells in vivo are exposed to multiple biophysical cues provided by the basement membrane, a specialized extracellular matrix through which vascular endothelial cells are attached to the underlying stroma. The importance of biophysical cues has been widely reported, but the signaling pathways that mediate cellular recognition and response to these cues remain poorly understood. Anisotropic topographically patterned substrates with nano- through microscale feature dimensions were fabricated to investigate cellular responses to topographic cues. The present study focuses on early events following exposure of human umbilical vein endothelial cells (HUVECs) to these patterned substrates. In serum-free medium and on substrates without protein coating, HUVECs oriented parallel to the long axis of underlying ridges in as little as 30 min. Immunocytochemistry showed clear differences in the localization of the focal adhesion proteins Src, p130Cas, and focal adhesion kinase (FAK) in HUVECs cultured on topographically patterned surfaces and on planar surfaces, suggesting involvement of these proteins in mediating the response to topographic features. Knockdown experiments demonstrated that FAK was not necessary for HUVEC alignment in response to topographic cues, although FAK knockdown did modulate HUVEC migration. These data identify key events early in the cellular response to biophysical stimuli.
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Affiliation(s)
- Britta Dreier
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, California, USA
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61
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McCracken KE, Tran PL, You DJ, Slepian MJ, Yoon JY. Shear- vs. nanotopography-guided control of growth of endothelial cells on RGD-nanoparticle-nanowell arrays. J Biol Eng 2013; 7:11. [PMID: 23607894 PMCID: PMC3637365 DOI: 10.1186/1754-1611-7-11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/09/2013] [Indexed: 11/24/2022] Open
Abstract
Endothelialization of therapeutic cardiovascular implants is essential for their intravascular hemocompatibility. We previously described a novel nanowell-RGD-nanoparticle ensemble, which when applied to surfaces led to enhanced endothelialization and retention under static conditions and low flow rates. In the present study we extend our work to determine the interrelated effects of flow rate and the orientation of ensemble-decorated surface arrays on the growth, adhesion and morphology of endothelial cells. Human umbilical vascular endothelial cells (HUVECs) were grown on array surfaces with either 1 μm × 5 μm spacing (“parallel to flow”) and 5 μm × 1 μm spacing (“perpendicular to flow”) and were exposed to a range of shear stress of (0 to 4.7 ± 0.2 dyn·cm-2 ), utilizing a pulsatile flow chamber. Under physiological flow (4.7 ± 0.2 dyn·cm-2), RGD-nanoparticle-nanowell array patterning significantly enhanced cell adhesion and spreading compared with control surfaces and with static conditions. Furthermore, improved adhesion coincided with higher alignment to surface patterning, intimating the importance of interaction and response to the array surface as a means of resisting flow detachment. Under sub-physiological condition (1.7 ± 0.3 dyn·cm-2; corresponding to early angiogenesis), nanowell-nanoparticle patterning did not provide enhanced cell growth and adhesion compared with control surfaces. However, it revealed increased alignment along the direction of flow, rather than the direction of the pattern, thus potentially indicating a threshold for cell guidance and related retention. These results could provide a cue for controlling cell growth and alignment under varying physiological conditions.
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Affiliation(s)
- Katherine E McCracken
- Department of Agricultural and Biosystems Engineering, The University of Arizona, Tucson, AZ, 85721, USA.
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Han J, Gerstenhaber JA, Lazarovici P, Lelkes PI. Tissue Factor Activity and ECM-Related Gene Expression in Human Aortic Endothelial Cells Grown on Electrospun Biohybrid Scaffolds. Biomacromolecules 2013; 14:1338-48. [DOI: 10.1021/bm400450m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Jingjia Han
- School
of Biomedical
Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104,
United States
| | - Jonathan A. Gerstenhaber
- School
of Biomedical
Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104,
United States
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, Pennsylvania 19122,
United States
| | - Philip Lazarovici
- School
of Biomedical
Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104,
United States
- School of Pharmacy
Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120,
Israel
| | - Peter I. Lelkes
- School
of Biomedical
Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104,
United States
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, Pennsylvania 19122,
United States
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Regulation of fibrochondrogenesis of mesenchymal stem cells in an integrated microfluidic platform embedded with biomimetic nanofibrous scaffolds. PLoS One 2013; 8:e61283. [PMID: 23637803 PMCID: PMC3630136 DOI: 10.1371/journal.pone.0061283] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 03/06/2013] [Indexed: 12/14/2022] Open
Abstract
In native fibrocartilage, mechanotransduction allows the cells to perceive the physical microenvironment not only through topographical cues from the extracellular matrix, but also through mechanical cues, such as interstitial flow. To create a microenvironment that simultaneously integrates nanotopography and flow stimulus, we developed a biomimetic microfluidic device embedded with aligned nanofibers to contain microchambers of different angles, which enabled the flow direction to form different angles with the fibers. Using this device, we investigated the effects of microfluidic and nanotopographical environment on the morphology and fibrochondrogenesis of mesenchymal stem cells (MSCs) and the involvement of RhoA/ROCK pathway and Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ). The results showed that the flow direction perpendicular to aligned nanofibers was conducive to fibrochondrogenesis of MSCs. In addition, ROCK inhibitor and knockdown of YAP/TAZ disrupted fibrochondrogenic differentiation of MSCs. In conclusion, our data suggest the crucial role of mechanotransduction in regulating fibrochondrogenic differentiation of MSCs, which may be mediated by RhoA/ROCK pathway and YAP/TAZ.
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Jantzen AE, Achneck HE, Truskey GA. Surface projections of titanium substrates increase antithrombotic endothelial function in response to shear stress. J Biomed Mater Res A 2013; 101:3181-91. [PMID: 23554161 DOI: 10.1002/jbm.a.34613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 12/21/2012] [Accepted: 01/22/2013] [Indexed: 11/06/2022]
Abstract
Despite the therapeutic benefits of both mechanical circulatory assist devices and nitinol stents with titanium (Ti) outer surfaces, problems remain with thrombosis at the blood-contacting surface. Covering these surfaces with a layer of endothelium would mimic the native lining of the cardiovascular system, potentially decreasing thrombotic complications. Since surface topography is known to affect the phenotype of a seeded cell layer and since stents and ventricular assist devices exhibit surface protrusions, we tested the hypothesis that endothelial cells (ECs) have altered function on Ti surfaces with protrusions of 1.25, 3, and 5 μm height, compared with smooth Ti surfaces. ECs and nuclei were more aligned and ECs were more elongated on all patterned surfaces. Cell area was reduced on the 3 and 5 μm features. Expression of eNOS and COX2 was not altered by patterned surfaces, but expression of KLF-2 was higher on 1.25 and 5 μm features. Nitric oxide production following exposure to flow was higher on the 5 μm features. These results show that some antithrombogenic functions of ECs are significantly enhanced for ECs cultured on surface protrusions, and no functions are diminished, informing the future design of implant surfaces for endothelialization.
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Affiliation(s)
- Alexandra E Jantzen
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, 27708
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Di Rienzo C, Jacchetti E, Cardarelli F, Bizzarri R, Beltram F, Cecchini M. Unveiling LOX-1 receptor interplay with nanotopography: mechanotransduction and atherosclerosis onset. Sci Rep 2013; 3:1141. [PMID: 23355954 PMCID: PMC3555090 DOI: 10.1038/srep01141] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 12/17/2012] [Indexed: 12/11/2022] Open
Abstract
Lectin-like ox-LDL receptors (LOX-1) play a crucial role in the ox-LDL–induced pathological transformation of vessel-wall components, a crucial early step in atherogenesis. LOX-1 dynamics is quantitatively investigated in human endothelial cells (HUVECs) exposed to environmental nanotopographies. We demonstrate distinct nanotopography-induced cell phenotypes, characterized by different morphology, LOX-1 diffusivity and oligomerization state: HUVECs on flat surfaces exhibit the behavior found in pro-atherogenic conditions, while growth on nanogratings can interfere with LOX-1 dynamics and lead to a behavior characteristic of normal, non-pathological conditions.
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Affiliation(s)
- Carmine Di Rienzo
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12 , 56127 Pisa, Italy
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66
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Franco D, Milde F, Klingauf M, Orsenigo F, Dejana E, Poulikakos D, Cecchini M, Koumoutsakos P, Ferrari A, Kurtcuoglu V. Accelerated endothelial wound healing on microstructured substrates under flow. Biomaterials 2012. [PMID: 23182348 DOI: 10.1016/j.biomaterials.2012.10.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding and accelerating the mechanisms of endothelial wound healing is of fundamental interest for biotechnology and of significant medical utility in repairing pathologic changes to the vasculature induced by invasive medical interventions. We report the fundamental mechanisms that determine the influence of substrate topography and flow on the efficiency of endothelial regeneration. We exposed endothelial monolayers, grown on topographically engineered substrates (gratings), to controlled levels of flow-induced shear stress. The wound healing dynamics were recorded and analyzed in various configurations, defined by the relative orientation of an inflicted wound, the topography and the flow direction. Under flow perpendicular to the wound, the speed of endothelial regeneration was significantly increased on substrates with gratings oriented in the direction of the flow when compared to flat substrates. This behavior is linked to the dynamic state of cell-to-cell adhesions in the monolayer. In particular, interactions with the substrate topography counteract Vascular Endothelial Cadherin phosphorylation induced by the flow and the wounding. This effect contributes to modulating the mechanical connection between migrating cells to an optimal level, increasing their coordination and resulting in coherent cell motility and preservation of the monolayer integrity, thus accelerating wound healing. We further demonstrate that the reduction of vascular endothelial cadherin phosphorylation, through specific inhibition of Src activity, enhances endothelial wound healing in flows over flat substrates.
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Affiliation(s)
- Davide Franco
- Laboratory of Thermodynamics in Emerging Technologies Sonneggstrasse 3, ML J 27.1 CH-8092 Zurich, Switzerland
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Brody S, Anilkumar T, Liliensiek S, Last JA, Murphy CJ, Pandit A. Characterizing nanoscale topography of the aortic heart valve basement membrane for tissue engineering heart valve scaffold design. TISSUE ENGINEERING 2006; 12:413-21. [PMID: 16548699 PMCID: PMC4820341 DOI: 10.1089/ten.2006.12.413] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A fully effective prosthetic heart valve has not yet been developed. A successful tissue-engineered valve prosthetic must contain a scaffold that fully supports valve endothelial cell function. Recently, topographic features of scaffolds have been shown to influence the behavior of a variety of cell types and should be considered in rational scaffold design and fabrication. The basement membrane of the aortic valve endothelium provides important parameters for tissue engineering scaffold design. This study presents a quantitative characterization of the topographic features of the native aortic valve endothelial basement membrane; topographical features were measured, and quantitative data were generated using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and light microscopy. Optimal conditions for basement membrane isolation were established. Histological, immunohistochemical, and TEM analyses following decellularization confirmed basement membrane integrity. SEM and AFM photomicrographs of isolated basement membrane were captured and quantitatively analyzed. The basement membrane of the aortic valve has a rich, felt-like, 3-D nanoscale topography, consisting of pores, fibers, and elevations. All features measured were in the sub-100 nm range. No statistical difference was found between the fibrosal and ventricular surfaces of the cusp. These data provide a rational starting point for the design of extracellular scaffolds with nanoscale topographic features that mimic those found in the native aortic heart valve basement membrane.
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Affiliation(s)
- Sarah Brody
- National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
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