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Zilla P, Deutsch M, Bezuidenhout D, Davies NH, Pennel T. Progressive Reinvention or Destination Lost? Half a Century of Cardiovascular Tissue Engineering. Front Cardiovasc Med 2020; 7:159. [PMID: 33033720 PMCID: PMC7509093 DOI: 10.3389/fcvm.2020.00159] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 07/28/2020] [Indexed: 12/19/2022] Open
Abstract
The concept of tissue engineering evolved long before the phrase was forged, driven by the thromboembolic complications associated with the early total artificial heart programs of the 1960s. Yet more than half a century of dedicated research has not fulfilled the promise of successful broad clinical implementation. A historical account outlines reasons for this scientific impasse. For one, there was a disconnect between distinct eras each characterized by different clinical needs and different advocates. Initiated by the pioneers of cardiac surgery attempting to create neointimas on total artificial hearts, tissue engineering became fashionable when vascular surgeons pursued the endothelialisation of vascular grafts in the late 1970s. A decade later, it were cardiac surgeons again who strived to improve the longevity of tissue heart valves, and lastly, cardiologists entered the fray pursuing myocardial regeneration. Each of these disciplines and eras started with immense enthusiasm but were only remotely aware of the preceding efforts. Over the decades, the growing complexity of cellular and molecular biology as well as polymer sciences have led to surgeons gradually being replaced by scientists as the champions of tissue engineering. Together with a widening chasm between clinical purpose, human pathobiology and laboratory-based solutions, clinical implementation increasingly faded away as the singular endpoint of all strategies. Moreover, a loss of insight into the healing of cardiovascular prostheses in humans resulted in the acceptance of misleading animal models compromising the translation from laboratory to clinical reality. This was most evident in vascular graft healing, where the two main impediments to the in-situ generation of functional tissue in humans remained unheeded–the trans-anastomotic outgrowth stoppage of endothelium and the build-up of an impenetrable surface thrombus. To overcome this dead-lock, research focus needs to shift from a biologically possible tissue regeneration response to one that is feasible at the intended site and in the intended host environment of patients. Equipped with an impressive toolbox of modern biomaterials and deep insight into cues for facilitated healing, reconnecting to the “user needs” of patients would bring one of the most exciting concepts of cardiovascular medicine closer to clinical reality.
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Affiliation(s)
- Peter Zilla
- Christiaan Barnard Division for Cardiothoracic Surgery, University of Cape Town, Cape Town, South Africa.,Cardiovascular Research Unit, University of Cape Town, Cape Town, South Africa
| | - Manfred Deutsch
- Karl Landsteiner Institute for Cardiovascular Surgical Research, Vienna, Austria
| | - Deon Bezuidenhout
- Cardiovascular Research Unit, University of Cape Town, Cape Town, South Africa
| | - Neil H Davies
- Cardiovascular Research Unit, University of Cape Town, Cape Town, South Africa
| | - Tim Pennel
- Christiaan Barnard Division for Cardiothoracic Surgery, University of Cape Town, Cape Town, South Africa
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Affiliation(s)
- P. Zilla
- Chris Barnard Division of Cardiothoracic Surgery, University Cape Town - South Africa
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Effect of TGF-β1 on the Migration and Recruitment of Mesenchymal Stem Cells after Vascular Balloon Injury: Involvement of Matrix Metalloproteinase-14. Sci Rep 2016; 6:21176. [PMID: 26880204 PMCID: PMC4754777 DOI: 10.1038/srep21176] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 01/19/2016] [Indexed: 01/02/2023] Open
Abstract
Restenosis or occlusion after vascular procedures is ascribed to intimal hyperplasia. Transforming growth factor (TGF)-β1 is involved in recruitment of mesenchymal stem cells (MSCs) following arterial injury, and its release from latent TGF-binding protein by matrix metalloproteinase (MMP)-14-induced proteolysis contributes to neointima formation. However, the relationship between MMP-14 and TGF-β1 activation in restenosis is unknown. This study investigated the relationship using a rat model of balloon-induced injury. Rats were assigned to vehicle-, SB431542 (SB)-, or recombinant human (rh)TGF-β1-treated groups and examined at various time points after balloon-induced injury for expression of TGF-β1/Smad signalling pathway components, MMP-14 and MSCs markers including Nestin, CD29, and Sca1+CD29+CD11b/c−CD45−. Intimal hyperplasia was reduced in SB- and rhTGF-β1-treated rats. The expression of TGF-β1, TGF-β1RI, and Smad2/3 was decreased, but the levels of phosphorylated Smad2/3 were higher in SB-treated rats than vehicle-treated after 7 days to 14 days. rhTGF-β1 administration decreased the expression of TGF-β1/Smad pathway proteins, except for TGF-β1RI. Nestin and CD29 expression and the number of Sca1+CD29+CD11b−CD45− cells were reduced, whereas MMP-14 expression was increased after SB431542 and rhTGF-β1 administration. These results suggest that TGF-β1/Smad signalling and MMP-14 act to recruit MSCs which differentiate to vascular smooth muscle cells and mesenchymal-like cells that participate in arterial repair/remodelling.
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Choi WS, Joung YK, Lee Y, Bae JW, Park HK, Park YH, Park JC, Park KD. Enhanced Patency and Endothelialization of Small-Caliber Vascular Grafts Fabricated by Coimmobilization of Heparin and Cell-Adhesive Peptides. ACS APPLIED MATERIALS & INTERFACES 2016; 8:4336-4346. [PMID: 26824876 DOI: 10.1021/acsami.5b12052] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The clinical utility of a small-caliber vascular graft is still limited, owing to the occlusion of graft by thrombosis and restenosis. A small-caliber vascular graft (diameter, 2.5 mm) fabricated by electrospinning with a polyurethane (PU) elastomer (Pellethane) and biofunctionalized with heparin and two cell-adhesive peptides, GRGDS and YIGSR, was developed for the purpose of preventing the thrombosis and restenosis through antithrombogenic activities and endothelialization. The vascular grafts showed slightly reduced adhesion of platelets and significantly decreased adsorption of fibrinogen. In vitro studies demonstrated that peptide treatment on a vascular graft enhanced the attachment of human umbilical vein endothelial cells (HUVECs), and the presence of heparin and peptides on the graft significantly increased the proliferation of HUVECs. In vivo implantation of heparin/peptides coimmobilized graft (PU-PEG-Hep/G+Y) and PU (control) grafts was performed using an abdominal aorta rabbit model for 60 days followed by angiographic monitoring and explanting for histological analyses. The patency was significantly higher for the modified PU grafts (71.4%) compared to the PU grafts (46.2%) at 9 weeks after implantation. The nontreated PU grafts showed higher levels of α-SMA expression compared to the modified grafts, and for both samples, the proximal and distal regions expressed higher levels compared to the middle region of the grafts. Moreover, immobilization of heparin and peptides and adequate porous structure were found to play important roles in endothelialization and cellular infiltration. Our results strongly encourage that the development of small-caliber vascular grafts is feasible.
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Affiliation(s)
- Won Sup Choi
- Department of Molecular Science and Technology, Ajou University , Suwon 443-749, Republic of Korea
| | - Yoon Ki Joung
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology , Seoul 136-791, Republic of Korea
| | - Yunki Lee
- Department of Molecular Science and Technology, Ajou University , Suwon 443-749, Republic of Korea
| | - Jin Woo Bae
- Department of Molecular Science and Technology, Ajou University , Suwon 443-749, Republic of Korea
| | | | | | | | - Ki Dong Park
- Department of Molecular Science and Technology, Ajou University , Suwon 443-749, Republic of Korea
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Effect of the P2Y12antagonist ticagrelor on neointimal hyperplasia in a rabbit carotid anastomosis model. Interact Cardiovasc Thorac Surg 2014; 19:198-204. [DOI: 10.1093/icvts/ivu087] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Albertine KH, Dezawa M. A new age of regenerative medicine: fusion of tissue engineering and stem cell research. Anat Rec (Hoboken) 2013; 297:1-3. [PMID: 24293066 DOI: 10.1002/ar.22811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 09/16/2013] [Indexed: 01/21/2023]
Affiliation(s)
- Kurt H Albertine
- Editor-in-Chief, The Anatomical Record, Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
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Guzeloglu M, Aykut K, Albayrak G, Atmaca S, Oktar S, Bagriyanik A, Hazan E. Effect of Tadalafil on Neointimal Hyperplasia in a Rabbit Carotid Artery Anastomosis Model. Ann Thorac Cardiovasc Surg 2013; 19:468-74. [DOI: 10.5761/atcs.oa.12.02017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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XIAO L, WEI Y, JI J. SURFACE TAILORING OF PTFE FOR ENDOTHELEAL CELLS SELECTIVITY BASED ON POLYDOPAMINE-ASSISTED SELF-ASSEMBLY MONOLAYER TECHNIQUE. ACTA POLYM SIN 2010. [DOI: 10.3724/sp.j.1105.2010.09307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Byrom MJ, Bannon PG, White GH, Ng MKC. Animal models for the assessment of novel vascular conduits. J Vasc Surg 2010; 52:176-95. [PMID: 20299181 DOI: 10.1016/j.jvs.2009.10.080] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 09/25/2009] [Accepted: 10/04/2010] [Indexed: 11/19/2022]
Abstract
The development of an ideal small-diameter conduit for use in vascular bypass surgery has yet to be achieved. The ongoing innovation in biomaterial design generates novel conduits that require preclinical assessment in vivo, and a number of animal models have been used for this purpose. This article examines the rationale behind animal models used in the assessment of small-diameter vascular conduits encompassing the commonly used species: baboons, sheep, pigs, dogs, rabbits, and rodents. Studies on the comparative hematology for these species relative to humans are summarized, and the hydrodynamic values for common implant locations are also compared. The large- and small-animal models are then explored, highlighting the characteristics of each that determine their relative utility in the assessment of vascular conduits. Where possible, the performance of expanded polytetrafluoroethylene is given in each animal and in each location to allow direct comparisons between species. New challenges in animal modeling are outlined for the assessment of tissue-engineered graft designs. Finally, recommendations are given for the selection of animal models for the assessment of future vascular conduits.
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Liu JC, Tirrell DA. Cell response to RGD density in cross-linked artificial extracellular matrix protein films. Biomacromolecules 2008; 9:2984-8. [PMID: 18826275 DOI: 10.1021/bm800469j] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This study examines the adhesion, spreading, and migration of human umbilical vein endothelial cells on cross-linked films of artificial extracellular matrix (aECM) proteins. The aECM proteins described here were designed for application in small-diameter grafts and are composed of elastin-like structural repeats and fibronectin cell-binding domains. aECM-RGD contains the RGD sequence derived from fibronectin; the negative control protein aECM-RDG contains a scrambled cell-binding domain. The covalent attachment of poly(ethylene glycol) (PEG) to aECM substrates reduced nonspecific cell adhesion to aECM-RDG-PEG but did not preclude sequence-specific adhesion of endothelial cells to aECM-RGD-PEG. Variation in ligand density was accomplished by the mixing of aECM-RGD-PEG and aECM-RDG-PEG prior to cross-linking. Increasing the density of RGD domains in cross-linked films resulted in more robust cell adhesion and spreading but did not affect cell migration speed. Control of cell-binding domain density in aECM proteins can thus be used to modulate cell adhesion and spreading and will serve as an important design tool as these materials are further developed for use in surgery, tissue engineering, and regenerative medicine.
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Affiliation(s)
- Julie C Liu
- Division of Chemistry and Chemical Engineering, Joseph J. Jacobs Institute for Molecular Engineering for Medicine, California Institute of Technology, Mail Code 210-41, Pasadena, California 91125, USA
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Monchaux E, Vermette P. Bioactive Microarrays Immobilized on Low-Fouling Surfaces to Study Specific Endothelial Cell Adhesion. Biomacromolecules 2007; 8:3668-73. [DOI: 10.1021/bm7007907] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Cavallaro G, Cucina A, Randone B, Polistena A, Mosiello G, Coluccia P, De Toma G, Cavallaro A. TIMP-2 Modulates Neointimal Formation in Experimental ePTFE Arterial Grafts. J Surg Res 2007; 137:122-9. [PMID: 17070550 DOI: 10.1016/j.jss.2006.07.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 07/25/2006] [Accepted: 07/26/2006] [Indexed: 11/29/2022]
Abstract
BACKGROUND In vascular reconstructive surgery, myointimal hyperplasia contributes to the adverse outcome of synthetic grafts. This phenomenon is because of unregulated extracellular matrix degradation and remodeling, and excessive smooth muscle cell proliferation and migration. Matrix metallopreoteinase 2 (MMP-2) is known as an important contributor to these events. The aims of our study was to investigate the effects of selective MMP-2 inhibitor (TIMP-2) in endothelialization rate, SMC proliferation, and myointimal hyperplasia in experimental ePTFE arterial grafts. METHODS In 20 male Lewis rats, a 1-cm long ePTFE graft has been inserted at the level of the abdominal aorta. Animals were randomized in two groups (10 animals each): group A received six subcutaneous inoculations of TIMP-2 (2.5 microg) after surgery, group B received only the vehicle of TIMP-2. RESULTS Neointimal thickness, as well as SMC density, were augmented in group B, whereas endothelial cells density was augmented in group A, and these findings were statistically significant. In group A SMC were better organized, just like SMC of thoracic aorta. In group B SMC were no organized. Furthermore, anti-TIMP-2 and anti-MMP-2 coloration revealed higher levels of TIMP-2 and lower levels of MMP-2 in group A versus group-B. CONCLUSIONS Use of TIMP-2 affects the neointimal formation of experimental e-PTFE arterial grafts, leading to a better-organized neointima, with improved endothelialization.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Antineoplastic Agents/pharmacology
- Aorta, Abdominal/metabolism
- Aorta, Abdominal/pathology
- Aorta, Abdominal/surgery
- Blood Vessel Prosthesis
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Endothelium, Vascular/surgery
- Extracellular Matrix/metabolism
- Immunohistochemistry
- Male
- Matrix Metalloproteinase 2/immunology
- Matrix Metalloproteinase 2/metabolism
- Matrix Metalloproteinase Inhibitors
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/surgery
- Polytetrafluoroethylene
- Postoperative Complications/drug therapy
- Postoperative Complications/metabolism
- Postoperative Complications/pathology
- Rats
- Rats, Inbred Lew
- Tissue Inhibitor of Metalloproteinase-2/immunology
- Tissue Inhibitor of Metalloproteinase-2/metabolism
- Tissue Inhibitor of Metalloproteinase-2/pharmacology
- Tunica Intima/metabolism
- Tunica Intima/pathology
- Tunica Intima/surgery
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Liu Tsang V, Chen AA, Cho LM, Jadin KD, Sah RL, DeLong S, West JL, Bhatia SN. Fabrication of 3D hepatic tissues by additive photopatterning of cellular hydrogels. FASEB J 2006; 21:790-801. [PMID: 17197384 DOI: 10.1096/fj.06-7117com] [Citation(s) in RCA: 375] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We have fabricated a hepatic tissue construct using a multilayer photopatterning platform for embedding cells in hydrogels of complex architecture. We first explored the potential of established hepatocyte culture models to stabilize isolated hepatocytes for photoencapsulation (e.g., double gel, Matrigel, cocultivation with nonparenchymal cells). Using photopolymerizable PEG hydrogels, we then tailored both the chemistry and architecture of the hydrogels to further support hepatocyte survival and liver-specific function. Specifically, we incorporated adhesive peptides to ligate key integrins on these adhesion-dependent cells. To identify the appropriate peptides for incorporation, the integrin expression of cultured hepatocytes was monitored by flow cytometry and their functional role in cell adhesion was assessed on full-length extracellular matrix (ECM) molecules and their adhesive peptide domains. In addition, we modified the hydrogel architecture to minimize barriers to nutrient transport for these highly metabolic cells. Viability of encapsulated cells was improved in photopatterned hydrogels with structural features of 500 microm in width over unpatterned, bulk hydrogels. Based on these findings, we fabricated a multilayer photopatterned PEG hydrogel structure containing the adhesive RGD peptide sequence to ligate the alpha5beta1 integrin of cocultured hepatocytes. Three-dimensional photopatterned constructs were visualized by digital volumetric imaging and cultured in a continuous flow bioreactor for 12 d where they performed favorably in comparison to unpatterned, unperfused constructs. These studies will have impact in the field of liver biology as well as provide enabling tools for tissue engineering of other organs.
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Affiliation(s)
- Valerie Liu Tsang
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
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Smith JT, Elkin JT, Reichert WM. Directed cell migration on fibronectin gradients: effect of gradient slope. Exp Cell Res 2006; 312:2424-32. [PMID: 16730349 DOI: 10.1016/j.yexcr.2006.04.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/27/2006] [Accepted: 04/17/2006] [Indexed: 11/25/2022]
Abstract
The migration of human microvascular endothelial cells (hMEC) was measured on a range of fibronectin gradient slopes. hMEC drift speed increased with increasing gradient slope with no concurrent change in cellular persistence time or random cell speed. The frequency of discrete cellular motion in the gradient direction increased with gradient slope. Morphological polarization of cells on the gradients is also characterized and correlated with cellular drift speed. These experiments present the first demonstration of cellular response to changing haptotactic gradient slope using an in vitro system for the quantitative study of cell migration.
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Affiliation(s)
- Jason T Smith
- Duke University Department of Biomedical Engineering, 136 Hudson Hall, Durham, NC 27708, USA.
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Vara DS, Salacinski HJ, Kannan RY, Bordenave L, Hamilton G, Seifalian AM. Cardiovascular tissue engineering: state of the art. ACTA ACUST UNITED AC 2005; 53:599-612. [PMID: 16364812 DOI: 10.1016/j.patbio.2004.12.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Accepted: 12/03/2004] [Indexed: 11/18/2022]
Abstract
In patients requiring coronary or peripheral vascular bypass procedures, autogenous arterial or vein grafts remain as the conduit of choice even in the case of redo patients. It is in this class of redo patients that often natural tissue of suitable quality becomes unavailable; so that prosthetic material is then used. Prosthetic grafts are liable to fail due to graft occlusion caused by surface thrombogenicity and lack of elasticity. To prevent this, seeding of the graft lumen with endothelial cells has been undertaken and recent clinical studies have evidenced patency rates approaching reasonable vein grafts. Recent advances have also looked at developing a completely artificial biological graft engineered from the patient's cells with surface and viscoelastic properties similar to autogenous vessels. This review encompasses both endothelialisation of grafts and the construction of biological cardiovascular conduits.
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Affiliation(s)
- Dina S Vara
- Biomaterial and Tissue Engineering Centre (BTEC), University Department of Surgery, Royal Free and University College Medical School, University College London, Rowland Hill Street, London NW3 2PF, UK
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Randone B, Cavallaro G, Polistena A, Cucina A, Coluccia P, Graziano P, Cavallaro A. Dual role of VEGF in pretreated experimental ePTFE arterial grafts. J Surg Res 2005; 127:70-9. [PMID: 15922362 DOI: 10.1016/j.jss.2004.09.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Revised: 07/14/2004] [Accepted: 09/02/2004] [Indexed: 01/08/2023]
Abstract
BACKGROUND Lack of endothelialization and abnormal smooth muscle cell (SMC) growth adversely affect the outcome of vascular synthetic grafts. The aims of our study were to investigate how a coating of extracellular matrix (ECM) and vascular endothelial growth factor (VEGF) might affect the endothelialization rate, smooth muscle cells (SMC) proliferation, and myointimal hyperplasia in experimental arterial ePTFE grafts. METHODS In each of 30 male Lewis rats, a 1-cm-long ePTFE graft was inserted at the level of the abdominal aorta. Animals were randomized in five groups (six animals each): groups A and A1 received ePTFE grafts coated with a synthetic extracellular matrix (growth factor-reduced matrigel) containing VEGF; groups B and B1 received ePTFE grafts coated with synthetic ECM; and group C received ePTFE grafts alone. The grafts were explanted at 30 days from surgery for immunohistochemical analysis. RESULTS Both endothelialization rate and myointimal hyperplasia were augmented in group A versus groups B and C, and these findings were statistically significant. SMC density resulted significantly higher in group A versus groups B and C, and this was associated with an altered expression of bFGF and TGFbeta. CONCLUSIONS Pretreating ePTFE grafts with synthetic ECM and VEGF results in better endothelialization, but also in undesired higher SMC density and myointimal hyperplasia.
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Affiliation(s)
- B Randone
- Department of Surgery "P. Valdoni," University "La Sapienza," Rome, Italy
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Kidd KR, Dal Ponte D, Stone AL, Hoying JB, Nagle RB, Williams SK. Stimulated endothelial cell adhesion and angiogenesis with laminin-5 modification of expanded polytetrafluoroethylene. TISSUE ENGINEERING 2005; 11:1379-91. [PMID: 16259593 DOI: 10.1089/ten.2005.11.1379] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Biomedical implants often exhibit poor clinical performance due to the formation of a periimplant avascular fibrous capsule. Surface modification of synthetic materials has been evaluated to accelerate the formation of functional microcirculation in association with implants. The current study used a flow-mediated protein deposition system to modify expanded polytetrafluoroethylene (ePTFE) with a laminin-5-rich conditioned growth medium and with medium from which laminin-5 had been selectively removed. An in vitro model of endothelial cell adherence determined that laminin-5 modification resulted in significantly increased adhesion of human microvessel endothelial cells to ePTFE. In vivo studies evaluating the periimplant vascular response to laminin-5-treated samples indicated that absorption of laminin-5-rich conditioned medium supported accelerated neovascularization of ePTFE implants. A flow system designed to treat porous implant materials facilitates laminin-5 modification of commercially available ePTFE, resulting in increased endothelial cell adhesion in vitro and increased vascularization in vivo.
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Affiliation(s)
- Kameha R Kidd
- Biomedical Engineering Program University of Arizona, Tucson, Arizona 85724, USA
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Kannan RY, Salacinski HJ, Sales K, Butler P, Seifalian AM. The roles of tissue engineering and vascularisation in the development of micro-vascular networks: a review. Biomaterials 2005; 26:1857-75. [PMID: 15576160 DOI: 10.1016/j.biomaterials.2004.07.006] [Citation(s) in RCA: 253] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 07/05/2004] [Indexed: 11/16/2022]
Abstract
The construction of tissue-engineered devices for medical applications is now possible in vitro using cell culture and bioreactors. Although methods of incorporating them back into the host are available, current constructs depend purely on diffusion which limits their potential. The absence of a vascular network capable of distributing oxygen and other nutrients within the tissue-engineered device is a major limiting factor in creating vascularised artificial tissues. Though bio-hybrid prostheses such as vascular bypass grafts and skin substitutes have already been developed and are being used clinically, the absence of a capillary bed linking the two systems remains the missing link. In this review, the different approaches currently being or that have been applied to vascularise tissues are identified and discussed.
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Affiliation(s)
- Ruben Y Kannan
- Biomaterials & Tissue Engineering Centre (BTEC), University Department of Surgery, Royal Free and University College Medical School, University College London, Rowland Hill Street, London NW3 2PF, UK
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Borschel GH, Huang YC, Calve S, Arruda EM, Lynch JB, Dow DE, Kuzon WM, Dennis RG, Brown DL. Tissue Engineering of Recellularized Small-Diameter Vascular Grafts. ACTA ACUST UNITED AC 2005; 11:778-86. [PMID: 15998218 DOI: 10.1089/ten.2005.11.778] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A tissue-engineered small-diameter arterial graft would be of benefit to patients requiring vascular reconstructive procedures. Our objective was to produce a tissue-engineered vascular graft with a high patency rate that could withstand arterial pressures. Rat arteries were acellularized with a series of detergent solutions, recellularized by incubation with a primary culture of endothelial cells, and implanted as interposition grafts in the common femoral artery. Acellular grafts that had not been recellularized were implanted in a separate group of control animals. No systemic anticoagulants were administered. Grafts were explanted at 4 weeks for definitive patency evaluation and histologic examination; 89% of the recellularized grafts and 29% of the control grafts remained patent. Elastin staining demonstrated the preservation of elastic fibers within the media of the acellular grafts before implantation. Immunohistochemical staining of explanted grafts demonstrated a complete layer of endothelial cells on the lumenal surface in grafts that remained patent. Smooth muscle cells were observed to have repopulated the vessel walls. The mechanical properties of the matrix were comparable to native vessels. Such a strategy may present an alternative to autologous harvest of small vessels for use in vascular bypass procedures.
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Affiliation(s)
- Gregory H Borschel
- Section of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
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20
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Meinhart JG, Schense JC, Schima H, Gorlitzer M, Hubbell JA, Deutsch M, Zilla P. Enhanced Endothelial Cell Retention on Shear-Stressed Synthetic Vascular Grafts Precoated with RGD-Cross-Linked Fibrin. ACTA ACUST UNITED AC 2005; 11:887-95. [PMID: 15998228 DOI: 10.1089/ten.2005.11.887] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Clinical in vitro endothelialization has been shown to increase the patency of synthetic vascular grafts. The shear stress resistance of the cultured autologous endothelium represents a crucial cornerstone of the concept. We investigated whether an enrichment of the precoating matrix with adhesion sites can augment endothelial cell attachment. Adult human saphenous vein endothelial cells (AHSVECs) were seeded confluently ([58 +/- 11] x 10(3) AHSVECs/cm2) onto 10-cm-long ePTFE (expanded polytetrafluorethylene) vascular grafts (n = 24) precoated with commercial clinically approved fibrin gel (Tisseal) containing various concentrations of cross-linked RGD peptide (0.0, 4.0, 8.0, or 16.0 mg of RGD per milliliter of Tisseal fibrinogen component). Endothelialized grafts were postcultivated for 9 days before they were exposed to a pulsatile circulation model mimicking peak physiological shear stress conditions of the femoral artery (12 dyn/cm2; min/max, -60/+28 dyn/cm2). Cell loss after 24 h was quantitatively determined by image analysis of vital stains. Initial 24-h cell loss was 27.2 +/- 1.7% in grafts precoated with the non-RGD-enriched fibrin matrix. In contrast, cell loss was significantly less on fibrin containing 4.0 mg of RGD peptide per milliliter of Tisseal fibrinogen component (13.3 +/- 7.9%; p < 0.05). Cell loss on fibrin containing 8 and 16 mg of RGD per milliliter of Tisseal fibrinogen component was 41.0 +/- 27.4 and 43.0 +/- 23.2% (p > 0.05), respectively. We conclude that low concentrations of RGD peptide cross-linked into commercial fibrin matrices used for clinical in vitro lining of vascular grafts led to significantly increased endothelial cell retention. The failure of higher RGD concentrations to enhance endothelial cell attachment may be explained by competitive binding of endothelial cells to non-cross-linked RGD.
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Ehrbar M, Metters A, Zammaretti P, Hubbell JA, Zisch AH. Endothelial cell proliferation and progenitor maturation by fibrin-bound VEGF variants with differential susceptibilities to local cellular activity. J Control Release 2005; 101:93-109. [PMID: 15588897 DOI: 10.1016/j.jconrel.2004.07.018] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Accepted: 07/13/2004] [Indexed: 11/17/2022]
Abstract
A number of vascular therapies could benefit from advanced methods for presentation of angiogenic growth factors, including growth of endothelium on small caliber vascular grafts and revascularization of ischemic tissue through induction of collateral vessels and microvessels. To explore methods to optimize the presentation and release of angiogenic factors in such applications in device integration and tissue repair, we studied three variant forms of vascular endothelial growth factor 121 (VEGF121), each with differential susceptibility to local cellular proteolytic activity, formulated within fibrin matrices. (1) The prototypic variant alpha2PI(1-8)-VEGF121 remains immobilized in fibrin matrices until its liberation by cell-associated enzymes, such as plasmin, that degrade the fibrin network [slow, cell-demanded release; J. Control. Release 72 (2001) 101-113]; the alpha2PI(1-8) domain serves as a site for covalent attachment to fibrin during coagulation. (2) We created a new VEGF variant, alpha2PI(1-8)-Pla-VEGF121 that couples to fibrin via a plasmin-sensitive sequence (Pla). Cleavage of this target site by plasmin enables direct release of alpha2PI(1-8)-Pla-VEGF121 from bulk matrix degradation (accelerated, cell-demanded release). (3) Native VEGF121 (burst, passive release) was considered as a reference. VEGF release profiles were determined experimentally as well as mathematically, alpha2PI(1-8)-Pla-VEGF121 being released ca. fourfold more quickly than alpha2PI(1-8)-VEGF121, both being retained compared to native VEGF121; the differences in release could be accounted for based on knowledge of the plasmin sensitivity of the bound growth factor and the structure of the fibrin network. The bound factors were competent in inducing endothelial cell proliferation, the matrix-bound forms being more effective than native VEGF121; as well as competent in inducing endothelial progenitor cell maturation into endothelial cells. These matrix-bound variants of VEGF121 may be particularly useful where retention in locally applied surgical sites is desired, such as prevention of washout from vascular graft coatings and slowing loss from tissue ingrowth matrices used in local tissue revascularization and repair.
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Affiliation(s)
- Martin Ehrbar
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
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Fittkau MH, Zilla P, Bezuidenhout D, Lutolf MP, Human P, Hubbell JA, Davies N. The selective modulation of endothelial cell mobility on RGD peptide containing surfaces by YIGSR peptides. Biomaterials 2005; 26:167-74. [PMID: 15207463 DOI: 10.1016/j.biomaterials.2004.02.012] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Accepted: 02/04/2004] [Indexed: 10/26/2022]
Abstract
The ability of the biomimetic peptides YIGSR, PHSRN and RGD to selectively affect adhesion and migration of human microvascular endothelial cells (MVEC) and vascular smooth muscle cells (HVSMC) was evaluated. Cell mobility was quantified by time-lapse video microscopy of single cells migrating on peptide modified surfaces. Polyethylene glycol (PEG) hydrogels modified with YIGSR or PHSRN allowed only limited adhesion and no spreading of MVEC and HVSMC. However, when these peptides were individually combined with the strong cell binding peptide RGD in PEG hydrogels, the YIGSR peptide was found to selectively enhance the migration of MVEC by 25% over that of MVEC on RGD alone (p<0.05). No corresponding effect was observed for HVSMC. This suggests that the desired response of specific cell types to tissue engineering scaffolds could be optimized through a combinatory approach to the use of biomimetic peptides.
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Affiliation(s)
- M H Fittkau
- Cardiovascular Research Unit, Christian Barnard Department of Cardiothoracic Surgery, Cape Heart Centre, University of Cape Town, Anzio Road, 7925 Observatory, Cape Town, South Africa
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Kannan RY, Salacinski HJ, Butler PE, Hamilton G, Seifalian AM. Current status of prosthetic bypass grafts: A review. J Biomed Mater Res B Appl Biomater 2005; 74:570-81. [PMID: 15889440 DOI: 10.1002/jbm.b.30247] [Citation(s) in RCA: 335] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Polymers such as Dacron and polytetrafluoroethylene (PTFE) have been used in high flow states with relative success but with limited application at lower flow states. Newer polymers with greater compliance, biomimicry, and ability to evolve into hybrid prostheses, suitable as smaller vessels, are now being introduced. In view of the advances in tissue engineering, this makes possible the creation of an ideal off-the-shelf bypass graft. We present a broad overview of the current state of prosthetic bypass grafts.
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Affiliation(s)
- Ruben Y Kannan
- Biomaterials & Tissue Engineering Centre, University Department of Surgery, Royal Free and University College Medical School, University College London, UK
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Abstract
Inadequate vascular perfusion leads to fatal heart attacks, chronic ulcers, and other serious clinical conditions. The body's capacity to restore vascular perfusion through angiogenesis and arteriogenesis is often impaired by pre-existing disease, and availability of native replacements for nonfunctional arteries is limited in many patients. Thus, recreating blood vessels of various calibres through novel engineering technologies has emerged as a radical option among therapeutic strategies for revascularization. Ranging from artificial, recycled or reassembled natural conduits to sophisticated microdevices, we refer to these as 'designer blood vessels'. Our common efforts to continuously improve vascular replacement design have provided many clues about our own blood vessels, but nature's ability to create nonthrombogenic, immunocompatible, strong, yet biologically responsive blood vessels remains unparalleled. Just as art reproductions never equal the original masterpiece, designer blood vessels may never attain nature's perfection. Nevertheless, they will provide a valuable option as long as they come close enough and are available to many.
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Affiliation(s)
- Joseph D Berglund
- Department of Medicine, Division of Cardiology, Emory University, 1639 Pierce Drive-WMB, Atlanta, GA 30322, U.S.A
| | - Zorina S Galis
- Department of Medicine, Division of Cardiology, Emory University, 1639 Pierce Drive-WMB, Atlanta, GA 30322, U.S.A
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, U.S.A
- Author for correspondence:
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Sagnella S, Kligman F, Marchant RE, Kottke-Marchant K. Biometric surfactant polymers designed for shear-stable endothelialization on biomaterials. J Biomed Mater Res A 2004; 67:689-701. [PMID: 14674370 DOI: 10.1002/jbm.a.10035] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We have developed a series of extracellular matrix (ECM)-like biomimetic surfactant polymers to improve endothelial cell adhesion and growth on vascular biomaterials. These polymers provide a single-step procedure for modifying the surface of existing biomaterials and consist of a poly(vinyl amine) (PVAm) backbone with varying ratios of cell-binding peptide (RGD) to carbohydrate (maltose), ranging from 100% RGD:0% maltose to 50% RGD:50% maltose. Three biomimetic surfaces, as well as a fibronectin (FN)-coated glass surface were seeded at confluence with human pulmonary artery endothelial cells (HPAECs) and exposed to shear stresses ranging from 0-40.6 dyn/cm2 for periods of 2 h and 6 h. Surfaces were examined for HPAEC coverage and cytoskeletal arrangement as a function of time and shear stress. In general, after 6 h of shear exposure, EC retention on 100% RGD > FN > 75% RGD > 50% RGD. The 100% RGD surface maintained more than 50% of its initial EC monolayer at low to moderate shear stresses whereas all other surfaces dropped to approximately 40% or less in the same shear stress range. The most stable surface, 100% RGD, showed a significant increase in cytoskeletal organization at all shear stresses greater than 2.5 dyn/cm2. In contrast, there was no real change in cytoskeletal organization on the FN surface, and there was a decrease on the 75% RGD surface over time. These results indicate that increasing surface peptide density can control EC shear stability. Furthermore, improved shear stability increases with increasing peptide density and is related to the EC's ability to reorganize its cytoskeleton.
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Affiliation(s)
- Sharon Sagnella
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Kidd KR, Williams SK. Laminin-5-enriched extracellular matrix accelerates angiogenesis and neovascularization in association with ePTFE. J Biomed Mater Res A 2004; 69:294-304. [PMID: 15058002 DOI: 10.1002/jbm.a.20133] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The performance of biomedical implant devices is often limited by inappropriate tissue responses associated with synthetic materials used in device construction. Adverse healing responses, in particular the lack of an extensive vascular supply in the peri-implant tissue, are believed to lead to the ultimate failure of many of these medical devices. Accelerated formation of new blood vessels in the peri-implant tissue and within porous polymeric implants is hypothesized to improve the performance of such biomedical implant devices. The current study evaluated the use of cell-mediated, extracellular matrix modification of expanded polytetrafluoroethylene (ePTFE) to increase vessel growth in peri-implant tissue and within the pores of the implants. Discs of ePTFE were modified through cell-mediated matrix deposition using epithelial and endothelial cell lines with variable deposition of collagen types, fibronectin, and laminin types. Cell matrix-modified discs, Matrigel-coated discs, and nonmodified discs were implanted in both the adipose and subcutaneous tissues of the rat. Following a 5-week implant period, samples were removed and evaluated histologically and morphometrically for the presence of blood vessels in the peri-implant tissue and within the pores of the polymer as well as for the presence of activated macrophages and monocytes. A significantly increased presence of activated macrophages and monocytes was associated only with the samples modified with the matrix from a human microvessel endothelial cell line. Increased vessel density was identified in association with those ePTFE samples modified with either the 804-G, HaCaT, or II-4 cell matrices, all of which have extracellular matrices enriched in the protein laminin-5.
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Affiliation(s)
- Kameha R Kidd
- Biomedical Engineering Program, University of Arizona, Tucson, Arizona 85724, USA
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Abstract
BACKGROUND There is an increased need for alternative, synthetic, small-diameter vascular grafts due to a growing segment of the population who suffer from ischemic heart disease and lack suitable autologous vein grafts for use in coronary artery bypass grafting (CABG). We hypothesized that a cell-mediated extracellular matrix (ECM) modification of ePTFE would stimulate increased vascularization within the graft and thus promote lumenal endothelialization in a 1-mm rat abdomenal aortic implant model. METHODS AND RESULTS Expanded polytetrafluoroethylene (ePTFE) vascular grafts (1 mm i.d.) were modified on the ablumenal surface with ECM deposited by the HaCaT or II-4 cell lines and implanted intrapositionally into the descending aorta of rats. Five weeks after implantation, all samples were patent and examination of the grafts demonstrated that the ECM modified samples exhibited extensive ablumenal vascularization and tissue incorporation compared to nonmodified samples. Also, ECM modified grafts had a cellular lining, while the nonmodified grafts were void of a cellular lining except for a limited pannus ingrowth. CONCLUSION HaCaT and II-4 cell ECM modifications of ePTFE increase new blood vessel growth in association with the graft, and the II-4 cell modification results in formation of an endothelial monlayer on the lumenal surface of the graft.
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Affiliation(s)
- Kameha R Kidd
- Biomedical Engineering Program, University of Arizona, Tucson, AZ 85724, USA
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