1
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Devadas D, Moore TA, Walji N, Young EWK. A microfluidic mammary gland coculture model using parallel 3D lumens for studying epithelial-endothelial migration in breast cancer. BIOMICROFLUIDICS 2019; 13:064122. [PMID: 31832120 PMCID: PMC6894982 DOI: 10.1063/1.5123912] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/06/2019] [Indexed: 05/02/2023]
Abstract
In breast cancer development, crosstalk between mammary epithelial cells and neighboring vascular endothelial cells is critical to understanding tumor progression and metastasis, but the mechanisms of this dynamic interplay are not fully understood. Current cell culture platforms do not accurately recapitulate the 3D luminal architecture of mammary gland elements. Here, we present the development of an accessible and scalable microfluidic coculture system that incorporates two parallel 3D luminal structures that mimic vascular endothelial and mammary epithelial cell layers, respectively. This parallel 3D lumen configuration allows investigation of endothelial-epithelial crosstalk and its effects of the comigration of endothelial and epithelial cells into microscale migration ports located between the parallel lumens. We describe the development and application of our platform, demonstrate generation of 3D luminal cell layers for endothelial cells and three different breast cancer cell lines, and quantify their migration profiles based on number of migrated cells, area coverage by migrated cells, and distance traveled by individual migrating cells into the migration ports. Our system enables analysis at the single-cell level, allows simultaneous monitoring of endothelial and epithelial cell migration within a 3D extracellular matrix, and has potential for applications in basic research on cellular crosstalk as well as drug development.
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Affiliation(s)
- Deepika Devadas
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Thomas A. Moore
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | | | - Edmond W. K. Young
- Author to whom correspondence should be addressed:. Tel.: +1 (416) 978-1521
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2
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Scheiner K, Maas-Bakker RF, Nguyen TT, Duarte AM, Hendriks G, Sequeira L, Duffy GP, Steendam R, Hennink WE, Kok RJ. Sustained Release of Vascular Endothelial Growth Factor from Poly(ε-caprolactone-PEG-ε-caprolactone)- b-Poly(l-lactide) Multiblock Copolymer Microspheres. ACS OMEGA 2019; 4:11481-11492. [PMID: 31460253 PMCID: PMC6681988 DOI: 10.1021/acsomega.9b01272] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/18/2019] [Indexed: 05/14/2023]
Abstract
Vascular endothelial growth factor (VEGF) is the major regulating factor for the formation of new blood vessels, also known as angiogenesis. VEGF is often incorporated in synthetic scaffolds to promote vascularization and to enhance the survival of cells that have been seeded in these devices. Such applications require sustained local delivery of VEGF of around 4 weeks for stable blood vessel formation. Most delivery systems for VEGF only provide short-term release for a couple of days, followed by a release phase with very low VEGF release. We now have developed VEGF-loaded polymeric microspheres that provide sustained release of bioactive VEGF for 4 weeks. Blends of two swellable poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone)-b-poly(l-lactide) ([PCL-PEG-PCL]-b-[PLLA])-based multiblock copolymers with different PEG content and PEG molecular weight were used to prepare the microspheres. Loading of the microspheres was established by a solvent evaporation-based membrane emulsification method. The resulting VEGF-loaded microspheres had average sizes of 40-50 μm and a narrow size distribution. Optimized formulations of a 50:50 blend of the two multiblock copolymers had an average VEGF loading of 0.79 ± 0.09%, representing a high average VEGF loading efficiency of 78 ± 16%. These microspheres released VEGF continuously over 4 weeks in phosphate-buffered saline pH 7.4 at 37 °C. This release profile was preserved after repeated and long-term storage at -20 °C for up to 9 months, thereby demonstrating excellent storage stability. VEGF release was governed by diffusion through the water-filled polymer matrix, depending on PEG molecular weight and PEG content of the polymers. The bioactivity of the released VEGF was retained within the experimental error in the 4-week release window, as demonstrated using a human umbilical vein endothelial cells proliferation assay. Thus, the microspheres prepared in this study are suitable for embedment in polymeric scaffolds with the aim of promoting their functional vascularization.
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Affiliation(s)
- Karina
C. Scheiner
- Department
of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Roel F. Maas-Bakker
- Department
of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Thanh T. Nguyen
- InnoCore
Pharmaceuticals B.V., L.J. Zielstraweg 1, 9713 GX Groningen, The Netherlands
| | - Ana M. Duarte
- InnoCore
Pharmaceuticals B.V., L.J. Zielstraweg 1, 9713 GX Groningen, The Netherlands
| | - Gert Hendriks
- InnoCore
Pharmaceuticals B.V., L.J. Zielstraweg 1, 9713 GX Groningen, The Netherlands
| | - Lídia Sequeira
- InnoCore
Pharmaceuticals B.V., L.J. Zielstraweg 1, 9713 GX Groningen, The Netherlands
| | - Garry P. Duffy
- Discipline
of Anatomy, School of Medicine, National
University of Ireland Galway, University Road, H91 TK33 Galway, Ireland
| | - Rob Steendam
- InnoCore
Pharmaceuticals B.V., L.J. Zielstraweg 1, 9713 GX Groningen, The Netherlands
| | - Wim E. Hennink
- Department
of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Robbert J. Kok
- Department
of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
- E-mail: . Phone: +31 620275995. Fax: +31 30 251789
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3
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Tissue Engineering to Repair Diaphragmatic Defect in a Rat Model. Stem Cells Int 2017; 2017:1764523. [PMID: 28928772 PMCID: PMC5592000 DOI: 10.1155/2017/1764523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/16/2017] [Accepted: 05/25/2017] [Indexed: 12/02/2022] Open
Abstract
Tissue engineering is an emerging strategy for repairing damaged tissues or organs. The current study explored using decellularized rat diaphragm scaffolds combined with human amniotic fluid-derived multipotent stromal cells (hAFMSC) to provide a scaffold, stem cell construct that would allow structural barrier function during tissue ingrowth/regeneration. We created an innovative cell infusion system that allowed hAFMSC to embed into scaffolds and then implanted the composite tissues into rats with surgically created left-sided diaphragmatic defects. Control rats received decellularized diaphragm scaffolds alone. We found that the composite tissues that combined hAFMSCs demonstrated improved physiological function as well as the muscular-tendon structure, compared with the native contralateral hemidiaphragm of the same rat. Our results indicate that the decellularized diaphragm scaffolds are a potential support material for diaphragmatic hernia repair and the composite grafts with hAFMSC are able to accelerate the functional recovery of diaphragmatic hernia.
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4
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Bekhite MM, Finkensieper A, Rebhan J, Huse S, Schultze-Mosgau S, Figulla HR, Sauer H, Wartenberg M. Hypoxia, Leptin, and Vascular Endothelial Growth Factor Stimulate Vascular Endothelial Cell Differentiation of Human Adipose Tissue-Derived Stem Cells. Stem Cells Dev 2014; 23:333-51. [DOI: 10.1089/scd.2013.0268] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Mohamed M. Bekhite
- Clinic of Internal Medicine I, Department of Cardiology, University Heart Center, Jena University Hospital, Jena, Germany
- Department of Zoology, Faculty of Science, Tanta University, Tanta, Egypt
| | - Andreas Finkensieper
- Clinic of Internal Medicine I, Department of Cardiology, University Heart Center, Jena University Hospital, Jena, Germany
| | - Jennifer Rebhan
- Clinic of Internal Medicine I, Department of Cardiology, University Heart Center, Jena University Hospital, Jena, Germany
| | - Stephanie Huse
- Clinic of Internal Medicine I, Department of Cardiology, University Heart Center, Jena University Hospital, Jena, Germany
| | - Stefan Schultze-Mosgau
- Department of Cranio-Maxillofacial Surgery and Plastic Surgery, Jena University Hospital, Jena, Germany
| | - Hans-Reiner Figulla
- Clinic of Internal Medicine I, Department of Cardiology, University Heart Center, Jena University Hospital, Jena, Germany
| | - Heinrich Sauer
- Department of Physiology, Faculty of Medicine, Justus Liebig University, Giessen, Germany
| | - Maria Wartenberg
- Clinic of Internal Medicine I, Department of Cardiology, University Heart Center, Jena University Hospital, Jena, Germany
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5
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Zhou H, Binmadi NO, Yang YH, Proia P, Basile JR. Semaphorin 4D cooperates with VEGF to promote angiogenesis and tumor progression. Angiogenesis 2012; 15:391-407. [PMID: 22476930 DOI: 10.1007/s10456-012-9268-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 03/20/2012] [Indexed: 02/08/2023]
Abstract
The semaphorins and plexins comprise a family of cysteine-rich proteins implicated in control of nerve growth and development and regulation of the immune response. Our group and others have found that Semaphorin 4D (SEMA4D) and its receptor, Plexin-B1, play an important role in tumor-induced angiogenesis, with some neoplasms producing SEMA4D in a manner analogous to vascular endothelial growth factor (VEGF) in order to attract Plexin-B1-expressing endothelial cells into the tumor for the purpose of promoting growth and vascularity. While anti-VEGF strategies have been the focus of most angiogenesis inhibition research, such treatment can lead to upregulation of pro-angiogenic factors that can compensate for the loss of VEGF, eventually leading to failure of therapy. Here, we demonstrate that SEMA4D cooperates with VEGF to promote angiogenesis in malignancies and can perform the same function in a setting of VEGF blockade. We also show the potential value of inhibiting SEMA4D/Plexin-B1 signaling as a complementary mechanism to anti-VEGF treatment, particularly in VEGF inhibitor-resistant tumors, suggesting that this may represent a novel treatment for some cancers.
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Affiliation(s)
- Hua Zhou
- Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650 West Baltimore Street, 7-North, Baltimore, MD 21201, USA
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6
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Wulf K, Teske M, Löbler M, Luderer F, Schmitz KP, Sternberg K. Surface functionalization of poly(ε-caprolactone) improves its biocompatibility as scaffold material for bioartificial vessel prostheses. J Biomed Mater Res B Appl Biomater 2011; 98:89-100. [DOI: 10.1002/jbm.b.31836] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 01/10/2011] [Accepted: 02/10/2011] [Indexed: 11/08/2022]
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7
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Wang W, Liu Y, Wang J, Jia X, Wang L, Yuan Z, Tang S, Liu M, Tang H, Yu Y. A Novel Copolymer Poly(Lactide-co-β-Malic Acid) with Extended Carboxyl Arms Offering Better Cell Affinity and Hemacompatibility for Blood Vessel Engineering. Tissue Eng Part A 2009; 15:65-73. [DOI: 10.1089/ten.tea.2007.0394] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Wei Wang
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, China
| | - Yuan Liu
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, China
| | - Jun Wang
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, China
| | - Xiaohua Jia
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, China
| | - Liang Wang
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, China
| | - Zhi Yuan
- Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, China
| | - Shiming Tang
- Tianjin Life Science Research Center, Tianjin Medical University, Tianjin, China
| | - Min Liu
- Tianjin Life Science Research Center, Tianjin Medical University, Tianjin, China
| | - Hua Tang
- Tianjin Life Science Research Center, Tianjin Medical University, Tianjin, China
| | - Yaoting Yu
- Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
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8
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Monahan TS, Andersen ND, Martin MC, Malek JY, Shrikhande GV, Pradhan L, Ferran C, LoGerfo FW. MARCKS silencing differentially affects human vascular smooth muscle and endothelial cell phenotypes to inhibit neointimal hyperplasia in saphenous vein. FASEB J 2008; 23:557-64. [PMID: 18940893 DOI: 10.1096/fj.08-114173] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Intimal hyperplasia (IH) limits the patency of all cardiovascular vein bypass grafts. We previously found the myristoylated alanine-rich C kinase substrate (MARCKS), a key protein kinase C (PKC) substrate, to be up-regulated in canine models of IH. Here, we further characterize the role of MARCKS in IH and examine the phenotypic consequences of MARCKS silencing by small interfering RNA (siRNA) transfection in human vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) in vitro and use a rapid 10-min nonviral siRNA transfection technique to determine the effects of MARCKS silencing in human saphenous vein cultured ex vivo. We demonstrate MARCKS silencing attenuates VSMC migration and arrests VSMC proliferation in part through the up-regulation of the cyclin-dependent kinase inhibitor p27(kip1). Conversely, MARCKS silencing had little or no effect on EC migration or proliferation. These phenotypic changes culminated in reduced neointimal formation in cultured human saphenous vein. These data identify MARCKS as a pathogenic contributor to IH and indicate therapeutic MARCKS silencing could selectively suppress the "atherogenic," proliferative phenotype of VSMCs without collateral harm to the endothelium. This approach could be readily translated to the clinic to silence MARCKS in vein bypass grafts prior to implantation.
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Affiliation(s)
- Thomas S Monahan
- Department of Surgery, Division of Vascular Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
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9
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Elbjeirami WM, West JL. Angiogenesis-like activity of endothelial cells co-cultured with VEGF-producing smooth muscle cells. ACTA ACUST UNITED AC 2006; 12:381-90. [PMID: 16548696 DOI: 10.1089/ten.2006.12.381] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A number of strategies have been investigated to improve therapeutic vascularization of ischemic and bioengineered tissues. In these studies, we genetically modified vascular smooth muscle cells (VSMC) to promote endothelial cell proliferation, migration, and formation of microvascular networks. VSMCs were virally transduced to produce vascular endothelial growth factor (VEGF), which acts as a chemoattractant and mitogen of endothelial cells (EC). VSMCs transduced with VEGF(165) cDNA produced significant levels of the protein (2-4 ng/10(5) cell/day). The proliferation of ECs increased after exposure to VEGF-transfected SMCs or their conditioned media. The chemotactic response of ECs to the VEGF-producing cells was explored in two in vitro systems, the modified Boyden chamber assay and a 2-D fence-style migration assay, and both demonstrated increased migration of ECs in response to VEGF-transfected cells. Furthermore, endothelial cells seeded on top of the VEGF-transfected SMCs formed capillary-like structures. These results suggest that VSMCs genetically modified to produce VEGF could be a potential delivery mechanism to enhance endothelial cell migration and subsequent capillary formation, which in turn could improve vascularization of ischemic or regenerating tissue. Furthermore, this system could potentially be used as an in vitro test bed for evaluation of novel angiogenic and anti-angiogenic compounds.
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MESH Headings
- Animals
- Aorta, Thoracic/cytology
- Blotting, Western
- Cell Movement
- Cell Proliferation
- Cells, Cultured
- Coculture Techniques
- Culture Media, Conditioned/chemistry
- DNA, Complementary
- Endothelium, Vascular/cytology
- Genetic Vectors
- Green Fluorescent Proteins/genetics
- Humans
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Neovascularization, Physiologic
- Rats
- Rats, Sprague-Dawley
- Retroviridae/genetics
- Umbilical Veins/cytology
- Vascular Endothelial Growth Factor A/physiology
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Affiliation(s)
- Wafa M Elbjeirami
- Department of Biochemistry & Cell Biology, Rice University, Houston, Texas, USA
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10
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Crombez M, Chevallier P, -Gaudreault RC, Petitclerc E, Mantovani D, Laroche G. Improving arterial prosthesis neo-endothelialization: application of a proactive VEGF construct onto PTFE surfaces. Biomaterials 2005; 26:7402-9. [PMID: 16005960 DOI: 10.1016/j.biomaterials.2005.05.051] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The formation of a confluent endothelium on expanded polytetrafluoroethylene (PTFE) vascular prostheses has never been observed. This lack of endothelialization is known to be one of the main reasons leading to the development of thromboses and/or intimal hyperplasia. In this context, several efforts were put forward to promote endothelial cell coverage on the internal surface of synthetic vascular prostheses. The goal of the present study was to immobilize the vascular endothelial growth factor (VEGF) onto Teflon PTFE surfaces to generate a proactive polymer construct favoring interaction with endothelial cells. An ammonia plasma treatment was first used to graft amino groups on PTFE films. Subsequent reactions were performed to covalently bind human serum albumin (HSA) on the polymer surface and to load this protein with negative charges, which allows adsorbtion of VEGF onto HSA via strong electrostatic interactions. X-ray photoelectron spectroscopy (XPS) experiments along with surface derivatization strategies were performed between each synthesis step to ascertain the occurrence of the various molecules surface immobilization. Finally, the electrostatic binding of VEGF to the negatively charged HSA matrix was performed and validated by ELISA. Endothelial cell adhesion and migration experiments were carried out to validate the potential of this VEGF-containing biological construct to act as a proactive media toward the development of endothelial cells.
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Affiliation(s)
- M Crombez
- Unité de Biotechnologie et de Bioingénierie, Centre de Recherche de l'Hôpital Saint-François d'Assise, C.H.U.Q., Qué., Canada G1L 3L5
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11
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Ito Y, Hasuda H, Terai H, Kitajima T. Culture of human umbilical vein endothelial cells on immobilized vascular endothelial growth factor. J Biomed Mater Res A 2005; 74:659-65. [PMID: 16035066 DOI: 10.1002/jbm.a.30360] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Vascular endothelial growth factor (VEGF) was immobilized on substrata in photoreactive gelatin to control the adhesion and growth of vascular endothelial cells. The gelatin and VEGF were mixed in water and cast on a polystyrene dish or a silane-coated glass plate. The surface was then photoirradiated in the presence or absence of a photomask and washed. Toughness of the immobilized material was confirmed by ethanol treatment. Human umbilical vein endothelial cells (HUVECs) grew on the immobilized VEGF but not on a nontreated surface. Growth of HUVEC increased significantly with an increase in the amount of immobilized VEGF, and the effects were inhibited by treatment with anti-VEGF antibody. Thus, immobilized VEGF specifically interacted with HUVECs to permit growth in culture. Micropatterning of HUVEC cultures was also achieved using micropattern-immobilized VEGF. This patterning technique may be useful for the formation of blood vessel networks in vitro.
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Affiliation(s)
- Yoshihiro Ito
- Kanagawa Academy of Science and Technology, KSP East 309, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan.
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12
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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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13
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Ng KW, Leong DTW, Hutmacher DW. The Challenge to Measure Cell Proliferation in Two and Three Dimensions. ACTA ACUST UNITED AC 2005; 11:182-91. [PMID: 15738673 DOI: 10.1089/ten.2005.11.182] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Various assays, using different strategies, are available for assessing cultured cell proliferation. These include measurement of metabolic activity (tetrazolium salts and alamarBlue), DNA quantification using fluorophores (Hoechst 33258 and PicoGreen), uptake of radioactively-labeled DNA precursors such as [3H]thymidine, and physical counting (hemocytometer). These assays are well established in characterizing cell proliferation in two-dimensional (2D), monolayer cultures of low cell densities. However, increasing interest in 3D cultures has prompted the need to evaluate the effectiveness of using these assays in high cell density or 3D cultures. We show here that typical cell proliferation assays do not necessarily correlate linearly with increasing cell densities or between 2D and 3D cultures, and are either not suitable or only rough approximations in quantifying actual cell numbers in a culture. Prudent choice of techniques and careful interpretation of data are therefore recommended when measuring cell proliferation in high cell density and 3D cultures.
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Affiliation(s)
- Kee W Ng
- Department of Surgery, National University of Singapore, Singapore
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14
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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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15
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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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16
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Nowatzki PJ, Tirrell DA. Physical properties of artificial extracellular matrix protein films prepared by isocyanate crosslinking. Biomaterials 2004; 25:1261-7. [PMID: 14643600 DOI: 10.1016/s0142-9612(03)00635-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Artificial extracellular matrix proteins, genetically engineered from elastin- and fibronectin-derived repeating units, were crosslinked with hexamethylene diisocyanate in dimethylsulfoxide. The resulting hydrogel films were transparent, uniform, and highly extensible. Their tensile moduli depended on crosslinker concentration and spanned the range characteristic of native elastin. The water content of the films was low ( approximately 27%), but the temperature-dependent swelling behavior of the crosslinked materials was reminiscent of the lower critical solution temperature property of the soluble polymers.
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Affiliation(s)
- Paul J Nowatzki
- Division of Chemistry and Chemical Engineering, 210-41, California Institute of Technology, Pasadena, CA 91125, USA
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Crombez M, Mantovani D. Progresses in synthetic vascular prostheses: toward the endothelialization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 534:165-77. [PMID: 12903719 DOI: 10.1007/978-1-4615-0063-6_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Affiliation(s)
- Mathilde Crombez
- Bioengineering and Biotechnology Unit, St-François d'Assise Hospital Research Centre and Laval University, Department of Materials Engineering, Laboratory for Biomaterials and Bioengineering, Quebec City, G1K 7P4, Canada
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