1
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Garcia N, Lau LDW, Lo CH, Cleland H, Akbarzadeh S. Understanding the mechanisms of spontaneous and skin-grafted wound repair: the path to engineered skin grafts. J Wound Care 2023; 32:55-62. [PMID: 36630112 DOI: 10.12968/jowc.2023.32.1.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Spontaneous wound repair is a complex process that involves overlapping phases of inflammation, proliferation and remodelling, co-ordinated by growth factors and proteases. In extensive wounds such as burns, the repair process would not be achieved in a timely fashion unless grafted. Although spontaneous wound repair has been extensively described, the processes by which wound repair mechanisms mediate graft take are yet to be fully explored. This review describes engraftment stages and summarises current understanding of molecular mechanisms which regulate autologous skin graft healing, with the goal of directing innovation in permanent wound closure with skin substitutes. Graftability and vascularisation of various skin substitutes that are either in the market or in development phase are discussed. In doing so, we cast a spotlight on the paucity of scientific information available as to how skin grafts (both autologous and engineered) heal a wound bed. Better understanding of these processes may assist in developing novel methods of wound management and treatments.
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Affiliation(s)
- Nicole Garcia
- Skin Bioengineering Laboratory, Victorian Adult Burns Service, Alfred Health, 89 Commercial Road, Melbourne, Victoria, Australia.,Department of Surgery, Monash University, 99 Commercial Road, Melbourne, Victoria, Australia
| | - Lachlan Dat Wah Lau
- Department of Surgery, Monash University, 99 Commercial Road, Melbourne, Victoria, Australia
| | - Cheng Hean Lo
- Department of Surgery, Monash University, 99 Commercial Road, Melbourne, Victoria, Australia
| | - Heather Cleland
- Skin Bioengineering Laboratory, Victorian Adult Burns Service, Alfred Health, 89 Commercial Road, Melbourne, Victoria, Australia.,Department of Surgery, Monash University, 99 Commercial Road, Melbourne, Victoria, Australia
| | - Shiva Akbarzadeh
- Skin Bioengineering Laboratory, Victorian Adult Burns Service, Alfred Health, 89 Commercial Road, Melbourne, Victoria, Australia.,Department of Surgery, Monash University, 99 Commercial Road, Melbourne, Victoria, Australia
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2
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Chogan F, Chen Y, Wood F, Jeschke MG. Skin Tissue Engineering Advances in Burns: A Brief Introduction to the Past, the Present, and the Future Potential. J Burn Care Res 2023; 44:S1-S4. [PMID: 36567473 DOI: 10.1093/jbcr/irac127] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Burn injuries are a severe form of skin damage with a significant risk of scarring and systemic sequelae. Approximately 11 million individuals worldwide suffer burn injuries annually, with 180,000 people dying due to their injuries. Wound healing is considered the main determinant for the survival of severe burns and remains a challenge. The surgical treatment of burn wounds entails debridement of necrotic tissue, and the wound is covered with autologous skin substitutes taken from healthy donor areas. Autologous skin transplantation is still considered to be the gold standard for wound repair. However, autologous skin grafts are not always possible, especially in cases with extensive burns and limited donor sites. Allografts from human cadaver skin and xenografts from pig skin may be used in these situations to cover the wounds temporarily. Alternatively, dermal analogs are used until permanent coverage with autologous skin grafts or artificial skins can be achieved, requiring staged procedures to prolong the healing times with the associated risks of local and systemic infection. Over the last few decades, the wound healing process through tissue-engineered skin substitutes has significantly enhanced as the advances in intensive care ensuring early survival have led to the need to repair large skin defects. The focus has shifted from survival to the quality of survival, necessitating accelerated wound repair. This special volume of JBCR is dedicated to the discoveries, developments, and applications leading the reader into the past, present, and future perspectives of skin tissue engineering in burn injuries.
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Affiliation(s)
- Faraz Chogan
- Sunnybrook Research Institute, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Yufei Chen
- Sunnybrook Research Institute, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Fiona Wood
- Department of Burns, Perth Children's Hospital, Nedlands, Western Australia, Australia.,Department of Burns, Fiona Stanley Hospital, Murdoch, Western Australia, Australia.,Division of Surgery, University of Western Australia, Crawley, Western Australia, Australia.,Burn Injury Research Unit, School of Biomedical Sciences, University of Western Australia, Crawley, Western Australia, Australia.,Fiona Wood Foundation, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
| | - Marc G Jeschke
- Sunnybrook Research Institute, Toronto, Ontario, Canada.,Department of Immunology, Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Division of Plastic and Reconstructive Surgery, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Ross Tilley Burn Centre, Sunnybrook Health Science Centre, Toronto, Ontario, Canada
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3
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Biomimetic nanofiber-enabled rapid creation of skin grafts. Nanomedicine (Lond) 2023. [DOI: 10.1016/b978-0-12-818627-5.00009-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
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4
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Bhar B, Chouhan D, Pai N, Mandal BB. Harnessing Multifaceted Next-Generation Technologies for Improved Skin Wound Healing. ACS APPLIED BIO MATERIALS 2021; 4:7738-7763. [PMID: 35006758 DOI: 10.1021/acsabm.1c00880] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dysregulation of sequential and synchronized events of skin regeneration often results in the impairment of chronic wounds. Conventional wound dressings fail to trigger the normal healing mechanism owing to the pathophysiological conditions. Tissue engineering approaches that deal with the fabrication of dressings using various biomaterials, growth factors, and stem cells have shown accelerated healing outcomes. However, most of these technologies are associated with difficulties in scalability and cost-effectiveness of the products. In this review, we survey the latest developments in wound healing strategies that have recently emerged through the multidisciplinary approaches of bioengineering, nanotechnology, 3D bioprinting, and similar cutting-edge technologies to overcome the limitations of conventional therapies. We also focus on the potential of wearable technology that supports complete monitoring of the changes occurring in the wound microenvironment. In addition, we review the role of advanced devices that can precisely enable the delivery of nanotherapeutics, oligonucleotides, and external stimuli in a controlled manner. These technological advancements offer the opportunity to actively influence the regeneration process to benefit the treatment regime further. Finally, the clinical relevance, trajectory, and prospects of this field have been discussed in brief that highlights their potential in providing a beneficial wound care solution at an affordable cost.
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Affiliation(s)
- Bibrita Bhar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Dimple Chouhan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Nakhul Pai
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Biman B Mandal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.,Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.,School of Health Science and Technology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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5
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Bédard P, Gauvin S, Ferland K, Caneparo C, Pellerin È, Chabaud S, Bolduc S. Innovative Human Three-Dimensional Tissue-Engineered Models as an Alternative to Animal Testing. Bioengineering (Basel) 2020; 7:E115. [PMID: 32957528 PMCID: PMC7552665 DOI: 10.3390/bioengineering7030115] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/12/2022] Open
Abstract
Animal testing has long been used in science to study complex biological phenomena that cannot be investigated using two-dimensional cell cultures in plastic dishes. With time, it appeared that more differences could exist between animal models and even more when translated to human patients. Innovative models became essential to develop more accurate knowledge. Tissue engineering provides some of those models, but it mostly relies on the use of prefabricated scaffolds on which cells are seeded. The self-assembly protocol has recently produced organ-specific human-derived three-dimensional models without the need for exogenous material. This strategy will help to achieve the 3R principles.
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Affiliation(s)
- Patrick Bédard
- Faculté de Médecine, Sciences Biomédicales, Université Laval, Québec, QC G1V 0A6, Canada; (P.B.); (S.G.); (K.F.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
| | - Sara Gauvin
- Faculté de Médecine, Sciences Biomédicales, Université Laval, Québec, QC G1V 0A6, Canada; (P.B.); (S.G.); (K.F.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
| | - Karel Ferland
- Faculté de Médecine, Sciences Biomédicales, Université Laval, Québec, QC G1V 0A6, Canada; (P.B.); (S.G.); (K.F.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
| | - Christophe Caneparo
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
| | - Ève Pellerin
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
| | - Stéphane Chabaud
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
| | - Stéphane Bolduc
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Centre de Recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice, Québec, QC G1J 1Z4, Canada; (C.C.); (È.P.); (S.C.)
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
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6
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Heller M, Bauer H, Schwab R, Blatt S, Peters K, Nezi‐Cahn S, Unger RE, Hasenburg A, Brenner W. The impact of intercellular communication for the generation of complex multicellular prevascularized tissue equivalents. J Biomed Mater Res A 2019; 108:734-748. [DOI: 10.1002/jbm.a.36853] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/21/2019] [Accepted: 11/22/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Martin Heller
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Heide‐Katharina Bauer
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Roxana Schwab
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Sebastian Blatt
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- Department of Maxillofacial Surgery University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Katharina Peters
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Sandra Nezi‐Cahn
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Ronald E. Unger
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- Institute for Pathology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Annette Hasenburg
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Walburgis Brenner
- Department of Gynecology University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
- BiomaTiCS—Biomaterials, Tissues and Cells in Science University Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
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7
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Mieremet A, van Dijk R, Boiten W, Gooris G, Bouwstra JA, El Ghalbzouri A. Characterization of human skin equivalents developed at body's core and surface temperatures. J Tissue Eng Regen Med 2019; 13:1122-1133. [PMID: 30945465 PMCID: PMC6767576 DOI: 10.1002/term.2858] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 02/19/2019] [Accepted: 03/13/2019] [Indexed: 12/18/2022]
Abstract
Human skin equivalents (HSEs) are in vitro developed three‐dimensional models resembling native human skin (NHS) to a high extent. However, the epidermal lipid biosynthesis, barrier lipid composition, and organization are altered, leading to an elevated diffusion rate of therapeutic molecules. The altered lipid barrier formation in HSEs may be induced by standardized culture conditions, including a culture temperature of 37°C, which is dissimilar to skin surface temperature. Therefore, we aim to determine the influence of culture temperature during the generation of full thickness models (FTMs) on epidermal morphogenesis and lipid barrier formation. For this purpose, FTMs were developed at conventional core temperature (37°C) or lower temperatures (35°C and 33°C) and evaluated over a time period of 4 weeks. The stratum corneum (SC) lipid composition was analysed using advanced liquid chromatography coupled to mass spectrometry analysis. Our results show that SC layers accumulated at a similar rate irrespective of culture temperature. At reduced culture temperature, an increased epidermal thickness, a disorganization of the lower epidermal cell layers, a delayed early differentiation, and an enlargement of granular cells were detected. Interestingly, melanogenesis was reduced at lower temperature. The ceramide subclass profile, chain length distribution, and level of unsaturated ceramides were similar in FTMs generated at 37°C and 35°C but changed when generated at 33°C, reducing the resemblance to NHS. Herein, we report that culture temperature affects epidermal morphogenesis substantially and to a lesser extent the lipid barrier formation, highlighting the importance of optimized external parameters during reconstruction of skin.
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Affiliation(s)
- Arnout Mieremet
- Department of Dermatology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Rianne van Dijk
- Research division BioTherapeutics, LACDR, Leiden University, Leiden, The Netherlands
| | - Walter Boiten
- Research division BioTherapeutics, LACDR, Leiden University, Leiden, The Netherlands
| | - Gert Gooris
- Research division BioTherapeutics, LACDR, Leiden University, Leiden, The Netherlands
| | - Joke A Bouwstra
- Research division BioTherapeutics, LACDR, Leiden University, Leiden, The Netherlands
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8
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Autologous and Allogeneic Skin Cell Grafts in the Treatment of Severely Burned Patients: Retrospective Clinical Study. Transplant Proc 2018; 50:2179-2187. [DOI: 10.1016/j.transproceed.2017.11.079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 11/21/2017] [Indexed: 12/15/2022]
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9
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Abstract
Advances in burn care have accelerated within the last 50 years. The principal modalities of and approaches to burn treatment include dressings, antimicrobials, fluid resuscitation, burn wound excision, skin grafting, and use of skin substitutes. This review presents a historical outline of these approaches, their current status, and prospects for the future of burn care.
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10
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Rahmani Del Bakhshayesh A, Annabi N, Khalilov R, Akbarzadeh A, Samiei M, Alizadeh E, Alizadeh-Ghodsi M, Davaran S, Montaseri A. Recent advances on biomedical applications of scaffolds in wound healing and dermal tissue engineering. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2017; 46:691-705. [PMID: 28697631 DOI: 10.1080/21691401.2017.1349778] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The tissue engineering field has developed in response to the shortcomings related to the replacement of the tissues lost to disease or trauma: donor tissue rejection, chronic inflammation and donor tissue shortages. The driving force behind the tissue engineering is to avoid the mentioned issues by creating the biological substitutes capable of replacing the damaged tissue. This is done by combining the scaffolds, cells and signals in order to create the living, physiological, three-dimensional tissues. A wide variety of skin substitutes are used in the treatment of full-thickness injuries. Substitutes made from skin can harbour the latent viruses, and artificial skin grafts can heal with the extensive scarring, failing to regenerate structures such as glands, nerves and hair follicles. New and practical skin scaffold materials remain to be developed. The current article describes the important information about wound healing scaffolds. The scaffold types which were used in these fields were classified according to the accepted guideline of the biological medicine. Moreover, the present article gave the brief overview on the fundamentals of the tissue engineering, biodegradable polymer properties and their application in skin wound healing. Also, the present review discusses the type of the tissue engineered skin substitutes and modern wound dressings which promote the wound healing.
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Affiliation(s)
- Azizeh Rahmani Del Bakhshayesh
- a Department of Medical Nanotechnology, Faculty of Advanced Medical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran.,b Student Research Committee , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Nasim Annabi
- c Biomaterials Innovation Research Center, Brigham and Women's Hospital , Harvard Medical School , Cambridge , MA , USA.,d Harvard-MIT Division of Health Sciences and Technology , Massachusetts Institute of Technology , Cambridge , MA , USA.,e Department of Chemical Engineering , Northeastern University , Boston , MA , USA
| | - Rovshan Khalilov
- f Institute of Radiation Problems , National Academy of Sciences of Azerbaijan , Baku , Azerbaijan
| | - Abolfazl Akbarzadeh
- g Stem Cell Research Center , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Mohammad Samiei
- a Department of Medical Nanotechnology, Faculty of Advanced Medical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran.,h Department of Endodontics, Faculty of Dentistry , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Effat Alizadeh
- i Drug Applied Research Center , Tabriz University of Medical Sciences , Tabriz , Iran
| | | | - Soodabeh Davaran
- i Drug Applied Research Center , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Azadeh Montaseri
- j Department of Anatomical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran
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11
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Co-stimulation of HaCaT keratinization with mechanical stress and air-exposure using a novel 3D culture device. Sci Rep 2016; 6:33889. [PMID: 27670754 PMCID: PMC5037429 DOI: 10.1038/srep33889] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/05/2016] [Indexed: 11/23/2022] Open
Abstract
Artificial skin or skin equivalents have been used for clinical purpose to skin graft and as substitutes for animal experiments. The culture of cell lines such as HaCaT has the potential to produce large amounts of artificial skin at a low cost. However, there is a limit to keratinization due to the restriction of differentiation in HaCaT. In this study, a culture device that mimics the in vivo keratinization mechanism, co-stimulated by air-exposure and mechanical stimulation, was developed to construct skin equivalents. The device can reconstruct the epidermal morphology, including the cornified layer, similar to its formation in vivo. Under the condition, epidermis was differentiated in the spinous and granular layers. Formation of the stratum corneum is consistent with the mRNA and protein expressions of differentiation markers. The device is the first of its kind to combine air-exposure with mechanical stress to co-stimulate keratinization, which can facilitate the economically viable production of HaCaT-based artificial skin substitutes.
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12
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Morales Hurtado M, de Vries EG, Zeng X, van der Heide E. A tribo-mechanical analysis of PVA-based building-blocks for implementation in a 2-layered skin model. J Mech Behav Biomed Mater 2016; 62:319-332. [PMID: 27236420 DOI: 10.1016/j.jmbbm.2016.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 01/14/2023]
Abstract
Poly(vinyl) alcohol hydrogel (PVA) is a well-known polymer widely used in the medical field due to its biocompatibility properties and easy manufacturing. In this work, the tribo-mechanical properties of PVA-based blocks are studied to evaluate their suitability as a part of a structure simulating the length scale dependence of human skin. Thus, blocks of pure PVA and PVA mixed with Cellulose (PVA-Cel) were synthesised via freezing/thawing cycles and their mechanical properties were determined by Dynamic Mechanical Analysis (DMA) and creep tests. The dynamic tests addressed to elastic moduli between 38 and 50kPa for the PVA and PVA-Cel, respectively. The fitting of the creep compliance tests in the SLS model confirmed the viscoelastic behaviour of the samples with retardation times of 23 and 16 seconds for the PVA and PVA-Cel, respectively. Micro indentation tests were also achieved and the results indicated elastic moduli in the same range of the dynamic tests. Specifically, values between 45-55 and 56-81kPa were obtained for the PVA and PVA-Cel samples, respectively. The tribological results indicated values of 0.55 at low forces for the PVA decreasing to 0.13 at higher forces. The PVA-Cel blocks showed lower friction even at low forces with values between 0.2 and 0.07. The implementation of these building blocks in the design of a 2-layered skin model (2LSM) is also presented in this work. The 2LSM was stamped with four different textures and their surface properties were evaluated. The hydration of the 2LSM was also evaluated with a corneometer and the results indicated a gradient of hydration comparable to the human skin.
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Affiliation(s)
- M Morales Hurtado
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
| | - E G de Vries
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
| | - X Zeng
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands; Advanced lubricating Materials Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Haike Road 100, Pudong, Shanghai, China
| | - E van der Heide
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands; TU Delft, Faculty of Civil Engineering and Geosciences, Stevinweg 1, 2628 CN Delft, The Netherlands
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13
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Shakya P, Sharma AK, Kumar N, Vellachi R, Mathew DD, Dubey P, Singh K, Shrivastava S, Shrivastava S, Maiti SK, Hasan A, Singh KP. Bubaline Cholecyst Derived Extracellular Matrix for Reconstruction of Full Thickness Skin Wounds in Rats. SCIENTIFICA 2016; 2016:2638371. [PMID: 27127678 PMCID: PMC4835655 DOI: 10.1155/2016/2638371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/06/2016] [Accepted: 02/28/2016] [Indexed: 06/05/2023]
Abstract
An acellular cholecyst derived extracellular matrix (b-CEM) of bubaline origin was prepared using anionic biological detergent. Healing potential of b-CEM was compared with commercially available collagen sheet (b-CS) and open wound (C) in full thickness skin wounds in rats. Thirty-six clinically healthy adult Sprague Dawley rats of either sex were randomly divided into three equal groups. Under general anesthesia, a full thickness skin wound (20 × 20 mm(2)) was created on the dorsum of each rat. The defect in group I was kept as open wound and was taken as control. In group II, the defect was repaired with commercially available collagen sheet (b-CS). In group III, the defect was repaired with cholecyst derived extracellular matrix of bovine origin (b-CEM). Planimetry, wound contracture, and immunological and histological observations were carried out to evaluate healing process. Significantly (P < 0.05) increased wound contraction was observed in b-CEM (III) as compared to control (I) and b-CS (II) on day 21. Histologically, improved epithelization, neovascularization, fibroplasia, and best arranged collagen fibers were observed in b-CEM (III) as early as on postimplantation day 21. These findings indicate that b-CEM have potential for biomedical applications for full thickness skin wound repair in rats.
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Affiliation(s)
- Poonam Shakya
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - A. K. Sharma
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Naveen Kumar
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Remya Vellachi
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Dayamon D. Mathew
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Prasoon Dubey
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Kiranjeet Singh
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Sonal Shrivastava
- Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Sameer Shrivastava
- Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - S. K. Maiti
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - Anwarul Hasan
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
| | - K. P. Singh
- Centre for Animal Disease Research and Diagnosis, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India
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14
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Tissue engineered pre-vascularized buccal mucosa equivalents utilizing a primary triculture of epithelial cells, endothelial cells and fibroblasts. Biomaterials 2016; 77:207-15. [DOI: 10.1016/j.biomaterials.2015.10.073] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/26/2015] [Accepted: 10/29/2015] [Indexed: 12/14/2022]
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Hewitt KJ, Shamis Y, Gerami-Naini B, Garlick JA. Strategies for Oral Mucosal Repair by Engineering 3D Tissues with Pluripotent Stem Cells. Adv Wound Care (New Rochelle) 2014; 3:742-750. [PMID: 25493208 DOI: 10.1089/wound.2013.0480] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 09/03/2013] [Indexed: 11/12/2022] Open
Abstract
Significance: Human-induced pluripotent stem cells (iPSC) can be differentiated into patient-specific cells with a wide spectrum of cellular phenotypes and offer an alternative source of autologous cells for therapeutic use. Recent studies have shown that iPSC-derived fibroblasts display enhanced cellular functions suggesting that iPSC may eventually become an important source of stem cells for regenerative therapies. Recent Advances: The discovery of approaches to reprogram somatic cells into pluripotent cells opens exciting avenues for their use in personalized, regenerative therapies. The controlled differentiation of functional cell types from iPSC provides a replenishing source of fibroblasts. There is intriguing evidence that iPSC reprogramming and subsequent differentiation to fibroblast lineages may improve cellular functional properties. Augmenting the biological potency of iPSC-derived fibroblasts may enable the development of novel, personalized stem cell therapies to treat oral disease. Critical Issues: Numerous questions need to be addressed before iPSC-derived cells can be used as a practical oral therapy. This will include understanding why iPSC-derived cells are predisposed towards differentiation pathways along lineages related to their cell of origin, screening iPSC-derived cells to ensure their safety and phenotypic stability and developing engineered, three-dimensional tissue models to optimize their function and efficacy for future therapeutic transplantation. Future Directions: Future research will need to address how to develop efficient methods to deliver and integrate iPSC-derived fibroblasts into the oral mucosa. This will require an improved understanding of how to harness their biological potency for regenerative therapies that are specifically targeted to the oral mucosa.
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Affiliation(s)
- Kyle J. Hewitt
- Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts
| | - Yulia Shamis
- Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts
| | - Behzad Gerami-Naini
- Department of Oral and Maxillofacial Pathology, Tufts University, Boston, Massachusetts
| | - Jonathan A. Garlick
- Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts
- Department of Oral and Maxillofacial Pathology, Tufts University, Boston, Massachusetts
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Shahrokhi S, Arno A, Jeschke MG. The use of dermal substitutes in burn surgery: acute phase. Wound Repair Regen 2014; 22:14-22. [PMID: 24393152 DOI: 10.1111/wrr.12119] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/12/2013] [Indexed: 11/30/2022]
Abstract
Major burns represent a challenge in autologous skin coverage and may lead to severe functional and cosmetic sequelae. Dermal substitutes are increasingly becoming an essential part of burn care during the acute phase of treatment. In the long term dermal substitutes improve functional and cosmetic results and thus enhance quality of life. In the chronic wound setting, dermal substitutes are used to reconstruct and improve burn scars and defects. Despite the potential of dermal substitutes, further research is required to strengthen scientific evidence regarding their effects and also to develop new technologies and products. Furthermore, dermal substitutes have a pivotal role in future research strategies as they have the potential to provide adequate scaffold for stem cells, tissue engineering, and regenerative medicine with conceivable application of obtaining long-lasting and scarless artificial skin. This review discusses the status quo of dermal substitutes and novel strategies in the use of dermal substitutes with a focus on burn care.
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Affiliation(s)
- Shahriar Shahrokhi
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
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Mayet N, Choonara YE, Kumar P, Tomar LK, Tyagi C, Du Toit LC, Pillay V. A comprehensive review of advanced biopolymeric wound healing systems. J Pharm Sci 2014; 103:2211-30. [PMID: 24985412 DOI: 10.1002/jps.24068] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 11/12/2022]
Abstract
Wound healing is a complex and dynamic process that involves the mediation of many initiators effective during the healing process such as cytokines, macrophages and fibroblasts. In addition, the defence mechanism of the body undergoes a step-by-step but continuous process known as the wound healing cascade to ensure optimal healing. Thus, when designing a wound healing system or dressing, it is pivotal that key factors such as optimal gaseous exchange, a moist wound environment, prevention of microbial activity and absorption of exudates are considered. A variety of wound dressings are available, however, not all meet the specific requirements of an ideal wound healing system to consider every aspect within the wound healing cascade. Recent research has focussed on the development of smart polymeric materials. Combining biopolymers that are crucial for wound healing may provide opportunities to synthesise matrices that are inductive to cells and that stimulate and trigger target cell responses crucial to the wound healing process. This review therefore outlines the processes involved in skin regeneration, optimal management and care required for wound treatment. It also assimilates, explores and discusses wound healing drug-delivery systems and nanotechnologies utilised for enhanced wound healing applications.
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Affiliation(s)
- Naeema Mayet
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Parktown, 2193, South Africa
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Drug Delivery to Wounds, Burns, and Diabetes-Related Ulcers. ADVANCES IN DELIVERY SCIENCE AND TECHNOLOGY 2014. [DOI: 10.1007/978-1-4614-9434-8_26] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Abstract
BACKGROUND Adult stem cells come from many sources and have the capacity to differentiate into many cell types, including those of the skin. The most commonly studied stem cells are those termed mesenchymal stem cells (MSCs), which are easily isolated from bone marrow and adipose tissue. Mesenchymal stem cells are known to produce a wide array of cytokines that modulate the regeneration process. The ease of collection, propagation and use of these MSCs in therapy of traumatic, ischaemic and immune-mediated skin conditions is emerging. APPROACH AND EVIDENCE In traumatic and ischaemic skin damage, MSCs are used in tissue-engineered skin and by direct injection into damaged tissue. For immune-mediated diseases, systemic administration of stem cells can modulate the immune system. The earliest clinical work has been with autologous stem cell sources, such as adipose tissue and bone marrow. In immune-mediated diseases, the MSCs are used to downregulate production of inflammatory cytokines and to block T-cell activation. Cells are generally given intravenously. Multiple sclerosis, rheumatoid arthritis and lupus have been successfully treated in human clinical trials. Mesenchymal stem cells can also stimulate resident local cells, such as keratinocytes and progenitor cells, to proliferate, migrate and repair skin injury and disease. LOOKING AHEAD The discovery of the MSC in adipose tissue has spawned a global effort to utilize these cells in therapy of a wide range of diseases of the skin. Reconstructive surgery, scar blocking and resolution and skin regeneration have all been shown to be possible in human and animal studies.
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Affiliation(s)
- Robert J Harman
- Vet-Stem, Inc., 12860 Danielson Court, Poway, CA 82064, USA.
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20
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Kamel RA, Ong JF, Eriksson E, Junker JPE, Caterson EJ. Tissue engineering of skin. J Am Coll Surg 2013; 217:533-55. [PMID: 23816384 DOI: 10.1016/j.jamcollsurg.2013.03.027] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 03/15/2013] [Accepted: 03/18/2013] [Indexed: 11/18/2022]
Affiliation(s)
- Rami A Kamel
- Division of Plastic Surgery, Brigham and Women's Surgery, Harvard Medical School, Boston, MA 02115, USA
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21
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Strategies to increase flap survival in nasal reconstruction in patients with deep panfacial burns. J Burn Care Res 2013; 34:e42-7. [PMID: 23135213 DOI: 10.1097/bcr.0b013e3182676c91] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Total nasal reconstruction requires the management of skin, cartilage, and nasal mucosa. This three-dimensional surgical approach is especially restricted in patients with severe deformities after deep panfacial burns. In this regard, the development of tissue fibrosis reduces the quality and reliability of surrounded donor sites, limiting the surgical options and flap survival outcomes. This report discusses the benefit of tissue protection procedures, such as flap delay and leech therapy, in the total nasal reconstruction of a patient with split-thickness skin grafts on donor sites for forehead and nasolabial flaps.
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Nair RP, Krishnan LK. Identification of p63+ keratinocyte progenitor cells in circulation and their matrix-directed differentiation to epithelial cells. Stem Cell Res Ther 2013; 4:38. [PMID: 23578397 PMCID: PMC3706939 DOI: 10.1186/scrt186] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 03/20/2013] [Indexed: 11/10/2022] Open
Abstract
Introduction In the event of chronic diabetes or burn wounds, accomplishing skin regeneration is a major concern. Autologous skin grafting is the most effective remedy, but the tissue harvest may create more nonhealing wounds. Currently available skin substitutes have a limited clinical outcome because of immune reactions arising from the xenobiotic scaffold or allogenous cells. Autologous stem cells that can be collected without an additional injury may be a viable option for skin-tissue engineering. Presence of a low number of keratinocyte progenitor cells (KPCs) within the peripheral blood mononuclear cell (PBMNC) population has been indicated. Identification, isolation, expansion, and differentiation of KPCs is necessary before they are considered for skin regeneration, which is the focus of this study. Methods Culture of isolated human PBMNCs on a cell-specific matrix was carried out to induce differentiation of KPCs. Flow cytometry and reverse transcriptase polymerase chain reaction were done for epithelial stem cell marker p63 and lineage markers cytokeratin 5 and cytokeratin 14, to track differentiation. Proliferation was confirmed by quantifying the proliferating cell nuclear antigen-expressing cells. Immunostaining with epithelial cell markers, involucrin and filaggrin, was carried out to establish terminal differentiation. Microscopic analysis confirmed growth and survival of KPCs on the dermal fibroblast monolayer and on a transplantable fibrin sheet. Results We demonstrated that KPCs are p63+ and CD34-. The specifically designed composition of the extracellular matrix was found to support selective adhesion, proliferation, and differentiation of p63+ KPCs. The PBMNC culture for 12 days under controlled conditions resulted in a homogenous population that expressed cytokeratins, and >90% of the cells were found to proliferate. Subculture for 5 days resulted in expression of filaggrin and involucrin, suggesting terminal differentiation. Transfer of matrix-selected KPCs to a dermal fibroblast monolayer or fibrin supported cell proliferation and showed typical hexagonal morphology of keratinocytes within 15 days. Conclusions Circulating KPCs were identified with p63, which differentiated into keratinocytes with expression of the cytokeratins, involucrin and filaggrin. Components of the specifically designed matrix favored KPC attachment, directed differentiation, and may turn out to be a potential vehicle for cell transplantation.
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Natesan S, Zamora DO, Wrice NL, Baer DG, Christy RJ. Bilayer Hydrogel With Autologous Stem Cells Derived From Debrided Human Burn Skin for Improved Skin Regeneration. J Burn Care Res 2013; 34:18-30. [DOI: 10.1097/bcr.0b013e3182642c0e] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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24
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Bush KA, Pins GD. Development of microfabricated dermal epidermal regenerative matrices to evaluate the role of cellular microenvironments on epidermal morphogenesis. Tissue Eng Part A 2012; 18:2343-53. [PMID: 22724677 DOI: 10.1089/ten.tea.2011.0479] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Topographic features at the dermal-epidermal junction (DEJ) provide instructive cues critical for modulating keratinocyte functions and enhancing the overall architecture and organization of skin. This interdigitated interface conforms to a series of rete ridges and papillary projections on the dermis that provides three-dimensional (3D) cellular microenvironments as well as structural stability between the dermal and epidermal layers during mechanical loading. The dimensions of these cellular microenvironments exhibit regional differences on the surface of the body, and quantitative histological analyses have shown that localization of highly proliferative keratinocytes also varies, according to the regional geometries of these microenvironments. In this study, we combined photolithography, collagen processing, and biochemical conjugation techniques to create microfabricated dermal epidermal regeneration matrices (μDERMs) with features that mimic the native 3D cellular microenvironment at the DEJ. We used this model system to study the effect of the 3D cellular microenvironment on epithelialization and basal keratinocyte interaction with the microenvironment on the surface of the μDERMs. We found that features closely mimicking those in high-friction areas of the body (deep, narrow channels) epithelialized faster than features mimicking low-friction areas. Additionally, when evaluating β1 expression, an integrin involved in epidermal morphogenesis, it was found that integrin-bright expression was localized in the depths of the features, suggesting that the μDERMs may play a role in defining cellular microenvironments as well as a protective environment for the regenerative population of keratinocytes. The outcomes of this study suggest that μDERMs can serve as a robust biomimetic model system to evaluate the roles of the 3D microenvironment on enhancing the regenerative capacity and structural stability of bioengineered skin substitutes.
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Affiliation(s)
- Katie A Bush
- Program in Biomedical Engineering and Medical Physics, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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25
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Abstract
Significant progress has been made over the years in the development of in vitro-engineered substitutes that mimic human skin, either to be used as grafts for the replacement of lost skin or for the establishment of human-based in vitro skin models. This review summarizes these advances in in vivo and in vitro applications of tissue-engineered skin. We further highlight novel efforts in the design of complex disease-in-a-dish models for studies ranging from disease etiology to drug development and screening.
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26
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Gauglitz GG, Zedler S, von Spiegel F, Fuhr J, von Donnersmarck GH, Faist E. Functional characterization of cultured keratinocytes after acute cutaneous burn injury. PLoS One 2012; 7:e29942. [PMID: 22359539 PMCID: PMC3281018 DOI: 10.1371/journal.pone.0029942] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 12/08/2011] [Indexed: 11/18/2022] Open
Abstract
Background In addition to forming the epithelial barrier against the outside environment keratinocytes are immunologically active cells. In the treatment of severely burned skin, cryoconserved keratinocyte allografts gain in importance. It has been proposed that these allografts accelerate wound healing also due to the expression of a favourable - keratinocyte-derived - cytokine and growth factor milieu. Methods In this study the morphology and cytokine expression profile of keratinocytes from skin after acute burn injury was compared to non-burned skin. Skin samples were obtained from patients after severe burn injury and healthy controls. Cells were cultured and secretion of selected inflammatory mediators was quantified using Bioplex Immunoassays. Immunohistochemistry was performed to analyse further functional and morphologic parameters. Results Histology revealed increased terminal differentiation of keratinocytes (CK10, CK11) in allografts from non-burned skin compared to a higher portion of proliferative cells (CK5, vimentin) in acute burn injury. Increased levels of IL-1α, IL-2, IL-4, IL-10, IFN-γ and TNFα could be detected in culture media of burn injury skin cultures. Both culture groups contained large amounts of IL-1RA. IL-6 and GM-CSF were increased during the first 15 days of culture of burned skin compared to control skin. Levels of VEGF, FGF-basic, TGF-ß und G-CSF were high in both but not significantly different. Cryoconservation led to a diminished mediator synthesis except for higher levels of intracellular IL-1α and IL-1ß. Conclusion Skin allografts from non-burned skin show a different secretion pattern of keratinocyte-derived cytokines and inflammatory mediators compared to keratinocytes after burn injury. As these secreted molecules exert auto- and paracrine effects and subsequently contribute to healing and barrier restoration after acute burn injury therapies affecting this specific cytokine/growth factor micromilieu could be beneficial in burned patients.
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Affiliation(s)
- Gerd G Gauglitz
- Department of Dermatology and Allergy, Ludwig-Maximilian University, Munich, Germany.
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27
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Fu X, Wang H. Rapid fabrication of biomimetic nanofiber-enabled skin grafts. Nanomedicine (Lond) 2012. [DOI: 10.1533/9780857096449.3.428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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28
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Sorrell JM, Baber MA, Traktuev DO, March KL, Caplan AI. The creation of an in vitro adipose tissue that contains a vascular-adipocyte complex. Biomaterials 2011; 32:9667-76. [PMID: 21959010 DOI: 10.1016/j.biomaterials.2011.08.090] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 08/31/2011] [Indexed: 11/16/2022]
Abstract
An increased demand for soft-tissue substitutes has impelled the development of an in vitro adipose tissue. Ideally, such a tissue should contain a vascular network that can deliver blood throughout the construct following its engraftment. This study describes the in vitro fabrication of a pre-vascularized adipose tissue entirely using a self-assembly approach. Adult human adipose stromal cells (ASCs) provided the foundation for this construct. These cells were cultured at high density in the presence of elevated levels of ascorbate prior to adipocytic induction. Vascular support cells consisting of dermal fibroblasts, mixtures of adipose stromal cells and bone marrow mesenchymal stem cells (MSCs) were introduced to sustain an extensive vascular network formed by human umbilical vein endothelial cells (HUVECs). MSCs were introduced to serve as perivascular cells. The resulting construct contained a vascular-adipose tissue continuum that was held together by basement membrane molecules. This construct contains multiple cell types that are typically found in adipose tissue: adipocytes, pre-adipocytes, stem cells, fibroblasts, vascular cells, and perivascular support cells. As such, these constructs can be employed both for in vitro studies to assay cellular interactions between vasculature and other components of adipose tissue. Further, they can also be engrafted into athymic hosts to study vascular and adipocyte stability.
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Affiliation(s)
- J Michael Sorrell
- Skeletal Research Center, Department of Biology, Case Western Reserve University, Cleveland, OH 44106, United States.
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29
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Auxenfans C, Lequeux C, Perrusel E, Mojallal A, Kinikoglu B, Damour O. Adipose-derived stem cells (ASCs) as a source of endothelial cells in the reconstruction of endothelialized skin equivalents. J Tissue Eng Regen Med 2011; 6:512-8. [DOI: 10.1002/term.454] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/11/2011] [Indexed: 12/22/2022]
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30
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Imbeault A, Bernard G, Ouellet G, Bouhout S, Carrier S, Bolduc S. Surgical option for the correction of Peyronie's disease: an autologous tissue-engineered endothelialized graft. J Sex Med 2011; 8:3227-35. [PMID: 21718447 DOI: 10.1111/j.1743-6109.2011.02374.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Surgical treatment is indicated in severe cases of Peyronie's disease. Incision of the plaque with subsequent graft material implantation is the option of choice. Ideal graft tissue is not yet available. AIM To evaluate the use of an autologous tissue-engineered endothelialized graft by the self-assembly method, for tunica albuginea (TA) reconstruction in Peyronie's disease. METHODS Two TA models were created. Human fibroblasts were isolated from a skin biopsy and cultured in vitro until formation of fibroblast sheets. After 4 weeks of maturation, human umbilical vein endothelial cells (HUVEC) were seeded on fibroblasts sheets and wrapped around a tubular support to form a cylinder of about 10 layers. After 21 days of tube maturation, HUVEC were seeded into the lumen of the fibroblast tubes for the endothelialized tunica albuginea (ETA). No HUVEC were seeded into the lumen for the TA model. Both constructs were placed under perfusion in a bioreactor for 1 week. MAIN OUTCOME MEASURES Histology, immunohistochemistry, and burst pressure were performed to characterize mature tubular graft. Animal manipulations were also performed to demonstrate the impact of endothelial cells in vivo. RESULTS Histology showed uniform multilayered fibroblasts. Extracellular matrix, produced entirely by fibroblasts, presented a good staining for collagen 1. Some elastin fibers were also present. For the TA model, anti-human von Willebrand antibody revealed the endothelial cells forming capillary-like structures. TA model reached a burst pressure of 584 mm Hg and ETA model obtained a burst pressure of 719 mm Hg. CONCLUSIONS This tissue-engineered endothelialized tubular graft is structurally similar to normal TA and presents an adequate mechanical resistance. The self-assembly method used and the autologous property of this model could represent an advantage comparatively to other available grafts. Further evaluation including functional testing will be necessary to characterize in vivo implantation and behavior of the graft.
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Affiliation(s)
- Annie Imbeault
- Department of Urology, CHUQ, Laval University, Quebec, Canada
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31
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Skin tissue engineering--in vivo and in vitro applications. Adv Drug Deliv Rev 2011; 63:352-66. [PMID: 21241756 DOI: 10.1016/j.addr.2011.01.005] [Citation(s) in RCA: 350] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 12/19/2010] [Accepted: 01/05/2011] [Indexed: 12/21/2022]
Abstract
Significant progress has been made over the years in the development of in vitro-engineered substitutes that mimic human skin, either to be used as grafts for the replacement of lost skin or for the establishment of human-based in vitro skin models. This review summarizes these advances in in vivo and in vitro applications of tissue-engineered skin. We further highlight novel efforts in the design of complex disease-in-a-dish models for studies ranging from disease etiology to drug development and screening.
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32
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Sorrell JM, Caplan AI. Topical delivery of mesenchymal stem cells and their function in wounds. Stem Cell Res Ther 2010; 1:30. [PMID: 20863417 PMCID: PMC2983443 DOI: 10.1186/scrt30] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mesenchymal stem cells are a heterogeneous population of fibroblast-like cells found in most adult organs. However, most of our current knowledge is based on cells of bone marrow or interstitial adipose tissues. These cells are capable of differentiation along various mesenchymal lineages. In addition, they have demonstrated therapeutic characteristics in wounds and ischemic situations. The therapeutic characteristics of these cells are activated upon their entering wounds or other damaged tissues. A current problem is the development of strategies that ensure that these cells reach wound beds in a timely fashion and in sufficient numbers to maximize their therapeutic benefits. Currently, there are two basic delivery methods: systemic infusion of cells into the vascular circulation and direct application of therapeutic cells to wound sites. Skin wounds are optimal candidates for the topical delivery approach. However, the methods by which therapeutic cells are delivered to such wounds vary. This review outlines the basic methods used to deliver therapeutic cells to skin and other wounds. Upon entering wounds, therapeutic cells interact with other wound cells through paracrine mechanisms that are not yet well understood. Nonetheless, interactions with vascular endothelial cells and immunomodulation appear to play significant roles in accelerating wound healing and in reducing scar formation upon the completion of the healing process. Although the phenomenological body of evidence indicating the efficacy of therapeutic cells is substantial, considerable work is still required to better determine the molecular and cellular functions of these cells and to assess their fate and the long-term consequences of their application.
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Affiliation(s)
- J Michael Sorrell
- Department of Biology, Skeletal Research Center, Case Western Reserve University, 2080 Adelbert Road, Cleveland, OH 44106, USA.
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Sorrell JM, Caplan AI. Fibroblasts-a diverse population at the center of it all. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 276:161-214. [PMID: 19584013 DOI: 10.1016/s1937-6448(09)76004-6] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The capacity of fibroblasts to produce and organize the extracellular matrix and to communicate with other cells makes them a central component of tissue biology. Even so, fibroblasts remain a somewhat enigmatic population. Our inability to fully comprehend these cells is in large part due to the paucity of unique cellular markers and to their pervasive diversity. Much of our understanding of fibroblast diversity has evolved from studies where subpopulations of these cells have been produced without resorting to cell surface markers. In this regard, cloning and mechanical separation of tissues prior to establishing cultures has provided multiple subpopulations. Nonetheless, in isolated situations, the expression or lack of expression of Thy-1/CD90 has been used to separate fibroblast subsets. The role of fibroblasts in intercellular communication is emerging through the implementation of organotypic studies in which three-dimensional fibroblast culture are combined with other populations of cells. Such studies have revealed critical paracrine loops that are essential for organ development and for wound repair. These studies also provide a backdrop for the emerging field of tissue engineering. The participation of fibroblasts in the regulation of tissue homeostasis and their contribution to the aging process are emerging issues that require better understanding. In short, fibroblasts represent a multifaceted, complex group of cells.
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Affiliation(s)
- J Michael Sorrell
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
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Halmy C, Nádai Z, Juhász Z, Pesthy P, Marczell Z, Szetei K, Szucs A. [Skin replacement with biological and biosynthetic materials following burn injury]. Orv Hetil 2008; 149:915-9. [PMID: 18467260 DOI: 10.1556/oh.2008.28223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Autotransplantation is currently regarded as the optimal skin replacement method, sufficient donor site, however, is often not available in extensively burned patients. Intensive research and development of skin replacement products is conducted worldwide in order to decrease the size of the required donor site. Short- and long-term wound coverage is made possible by temporary synthetic and non-synthetic skin substitutes. Autografts and cultured epithelial autografts are used for permanent skin substitution. Until this is possible, the barrier function of the skin is provided by bio-engineered temporary skin substitutes. Some products and methods are currently available in Hungary, while others are still in the introductory phase. In order to provide an overview, authors summarize the skin replacement methods and compare the different skin replacement products used worldwide from the perspective of the burn surgeon. The use of new methods to be introduced in the near future needs to be rationalized due to financial considerations.
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Affiliation(s)
- Csaba Halmy
- Allami Egészségügyi Központ Baleseti Sebészeti Osztály, Plasztikai és Egési Sebészeti Részleg Budapest.
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Smiley AK, Gardner J, Klingenberg JM, Neely AN, Supp DM. Expression of Human Beta Defensin 4 in Genetically Modified Keratinocytes Enhances Antimicrobial Activity. J Burn Care Res 2007; 28:127-32. [PMID: 17211212 DOI: 10.1097/bcr.0b013e31802c88fd] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Defensins are cationic peptides of the innate host defense system with antimicrobial activity against many of the microorganisms commonly found in burn units. Beta defensins are variably expressed in the epithelia of skin and other organs. Human beta defensin 4 reportedly has antimicrobial activity against Pseudomonas aeruginosa and is not normally expressed in intact skin. Genetic modification was used to ectopically express human beta defensin 4 in cultured primary epidermal keratinocytes. Keratinocytes expressing human beta defensin 4 showed significantly elevated antimicrobial activity against clinically-isolated P. aeruginosa compared with controls. These results suggest that genetic modification of keratinocytes can increase their resistance to microbial contamination. Bioengineered skin replacements containing human beta defensin 4-modified keratinocytes may be useful for transplantation to contaminated burn wounds.
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Affiliation(s)
- Andrea K Smiley
- Shriners Hospitals for Children, Cincinnati Burns Hospital, Ohio 45229, USA
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36
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Bush KA, Downing BR, Walsh SE, Pins GD. Conjugation of extracellular matrix proteins to basal lamina analogs enhances keratinocyte attachment. J Biomed Mater Res A 2006; 80:444-52. [PMID: 17013864 DOI: 10.1002/jbm.a.30933] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The dermal-epidermal junction of skin contains extracellular matrix proteins that are involved in initiating and controlling keratinocyte signaling events such as attachment, proliferation, and terminal differentiation. To characterize the relationship between extracellular matrix proteins and keratinocyte attachment, a biomimetic design approach was used to precisely tailor the surface of basal lamina analogs with biochemistries that emulate the native biochemical composition found at the dermal-epidermal junction. A high-throughput screening device was developed by our laboratory that allows for the simultaneous investigation of the conjugation of individual extracellular matrix proteins (e.g. collagen type I, collagen type IV, laminin, or fibronectin) as well as their effect on keratinocyte attachment, on the surface of an implantable collagen membrane. Fluorescence microscopy coupled with quantitative digital image analyses indicated that the extracellular matrix proteins adsorbed to the collagen-GAG membranes in a dose-dependent manner. To determine the relationship between extracellular matrix protein signaling cues and keratinocyte attachment, cells were seeded on protein-conjugated collagen-GAG membranes and a tetrazolium-based colorimetric assay was used to quantify viable keratinocyte attachment. Our results indicate that keratinocyte attachment was significantly enhanced on the surfaces of collagen membranes that were conjugated with fibronectin and type IV collagen. These findings define a set of design parameters that will enhance keratinocyte binding efficiency on the surface of collagen membranes and ultimately improve the rate of epithelialization for dermal equivalents.
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Affiliation(s)
- Katie A Bush
- Worcester Polytechnic Institute, Biomedical Engineering, Worcester, Massachusetts, USA
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Sun T, Norton D, Haycock JW, Ryan AJ, MacNeil S. Development of a Closed Bioreactor System for Culture of Tissue-Engineered Skin at an Air–Liquid Interface. ACTA ACUST UNITED AC 2005; 11:1824-31. [PMID: 16411828 DOI: 10.1089/ten.2005.11.1824] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A bioreactor has been developed for the production of tissue-engineered skin at an air-liquid interface for clinical and experimental use. In this closed system, scaffold and bioreactor sterilization, cell seeding, and medium perfusion were all performed with a peristaltic pump. Natural and synthetic dermal substitutes were seeded directly with skin cells without opening the bioreactor and fed either by continuous medium perfusion or by batch-feed. The system was validated by monoculture of human dermal fibroblasts and keratinocytes and the coculture of both cell types in acellular human dermis, Azowipes, electrospun polystyrene, and an electrospun composite of polystyrene and poly-DL-lactide fibers. A comparison was made of culture at an air-liquid interface versus submerged culture and of medium change by continuous perfusion versus batch-feed. Fibroblast and endothelial cells showed greater viability under submerged rather than air-liquid conditions whereas keratinocytes favored culture at an air-liquid interface as did cocultured keratinocytes and fibroblasts. Total cellular viability for reconstructed skin with keratinocytes and fibroblasts was greatest with continuous perfusion rather than batch-feed and with electrospun scaffolds compared with acellular human dermis. The bioreactor could also be easily configured to give replicate small areas for experimental use or one continuous area of construct for clinical use.
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Affiliation(s)
- Tao Sun
- Department of Engineering Materials, Sheffield University, Sheffield, UK
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Tremblay PL, Hudon V, Berthod F, Germain L, Auger FA. Inosculation of tissue-engineered capillaries with the host's vasculature in a reconstructed skin transplanted on mice. Am J Transplant 2005; 5:1002-10. [PMID: 15816880 DOI: 10.1111/j.1600-6143.2005.00790.x] [Citation(s) in RCA: 251] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The major limitation for the application of an autologous in vitro tissue-engineered reconstructed skin (RS) for the treatment of burnt patients is the delayed vascularization of its relatively thick dermal avascular component, which may lead to graft necrosis. We have developed a human endothelialized reconstructed skin (ERS), combining keratinocytes, fibroblasts and endothelial cells (EC) in a collagen sponge. This skin substitute then spontaneously forms a network of capillary-like structures (CLS) in vitro. After transplantation to nude mice, we demonstrated that CLS containing mouse blood were observed underneath the epidermis in the ERS in less than 4 days, a delay comparable to our human skin control. In comparison, a 14-day period was necessary to achieve a similar result with the non-endothelialized RS. Furthermore, no mouse blood vessels were ever observed close to the epidermis before 14 days in the ERS and the RS. We thus concluded that the early vascularization observed in the ERS was most probably the result of inosculation of the CLS network with the host's capillaries, rather than neovascularization, which is a slower process. These results open exciting possibilities for the clinical application of many other tissue-engineered organs requiring a rapid vascularization.
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Affiliation(s)
- Pierre-Luc Tremblay
- Laboratoire d'organogénèse Expérimentale, Centre hospitalier affilié universitaire de Québec, Hôpital du St-Sacrement and Département de chirurgie, Québec, Canada
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Erdag G, Medalie DA, Rakhorst H, Krueger GG, Morgan JR. FGF-7 expression enhances the performance of bioengineered skin. Mol Ther 2005; 10:76-85. [PMID: 15233944 DOI: 10.1016/j.ymthe.2004.04.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Accepted: 04/18/2004] [Indexed: 10/26/2022] Open
Abstract
To improve the performance of bioengineered skin, we used a recombinant retrovirus encoding FGF-7 to modify diploid human keratinocytes genetically. Control or FGF-7-expressing keratinocytes were seeded onto acellular human dermis to form bioengineered skin. Gene-modified skin secreted significant levels of FGF-7 and formed a thicker and hyperproliferative epidermis with about four times the number of cells per square centimeter. Secretion of an endogenous trophic factor, VEGF, was increased approximately 5-fold. Migration of FGF-7-expressing keratinocytes was stimulated as was the self-healing of bioengineered skin expressing FGF-7. When tested in a bacterial infection model, the antimicrobial properties of FGF-7-expressing skin were increased >500-fold against both gram-negative and gram-positive bacteria. After transplantation to full-thickness wounds on athymic mice, skin expressing FGF-7 was revascularized more rapidly. These results demonstrate that genetic modification can be used to enhance performance and that expression of FGF-7 augments several properties important to the wound-healing properties of bioengineered skin.
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Affiliation(s)
- Gulsun Erdag
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School and Shriners Hospital for Children, Boston, MA 02114, USA
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40
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Fabrication, quality assurance, and assessment of cultured skin substitutes for treatment of skin wounds. Biochem Eng J 2004. [DOI: 10.1016/j.bej.2003.09.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Sorrell JM, Baber MA, Caplan AI. Site-matched papillary and reticular human dermal fibroblasts differ in their release of specific growth factors/cytokines and in their interaction with keratinocytes. J Cell Physiol 2004; 200:134-45. [PMID: 15137066 DOI: 10.1002/jcp.10474] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The interfollicular dermis of adult human skin is partitioned into histologically and physiologically distinct papillary and reticular zones. Each of these zones contains a unique population of fibroblasts that differ in respect to their proliferation kinetics, rates at which they contract type I collagen gels, and in their relative production of decorin and versican. Here, site-matched papillary and reticular dermal fibroblasts couples were compared to determine whether each population interacted with keratinocytes in an equivalent or different manner. Papillary and reticular fibroblasts grown in monolayer culture differed significantly from each other in their release of keratinocyte growth factor (KGF) and granulocyte-macrophage colony stimulating factor (GM-CSF) into culture medium. Some matched fibroblast couples also differed in their constitutive release of interleukin-6 (IL-6). Papillary fibroblasts produced a higher ratio of GM-CSF to KGF than did corresponding reticular fibroblasts. Interactions between site-matched papillary and reticular couples were also assayed in a three-dimensional culture system where fibroblasts and keratinocytes were randomly mixed, incorporated into type I collagen gels, and allowed to sort. Keratinocytes formed distinctive cellular masses in which the keratinocytes were organized such that the exterior most layer of cells exhibited characteristics of basal keratinocytes and the interior most cells exhibited characteristics of terminally differentiated keratinocytes. In the presence of papillary dermal fibroblasts, keratinocyte masses were highly symmetrical and cells expressed all levels of differentiation markers. In contrast, keratinocyte masses that formed in the presence of reticular fibroblasts tended to have irregular shapes, and terminal differentiation was suppressed. Furthermore, basement membrane formation was retarded in the presence of reticular cells. These studies indicate that site-matched papillary and reticular dermal fibroblasts qualitatively differ in their support of epidermal cells, with papillary cells interacting more effectively than corresponding reticular cells.
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Affiliation(s)
- J Michael Sorrell
- Biology Department, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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Abstract
Dermal fibroblasts are a dynamic and diverse population of cells whose functions in skin in many respects remain unknown. Normal adult human skin contains at least three distinct subpopulations of fibroblasts, which occupy unique niches in the dermis. Fibroblasts from each of these niches exhibit distinctive differences when cultured separately. Specific differences in fibroblast physiology are evident in papillary dermal fibroblasts, which reside in the superficial dermis, and reticular fibroblasts, which reside in the deep dermis. Both of these subpopulations of fibroblasts differ from the fibroblasts that are associated with hair follicles. Fibroblasts engage in fibroblast-epidermal interactions during hair development and in interfollicular regions of skin. They also play an important role in cutaneous wound repair and an ever-increasing role in bioengineering of skin. Bioengineered skin currently performs important roles in providing (1) a basic understanding of skin biology, (2) a vehicle for testing topically applied products and (3) a resource for skin replacement.
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Affiliation(s)
- J Michael Sorrell
- Skeletal Research Center, Biology Department, Case Western Reserve University, Cleveland, OH 44106, USA.
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Downing BR, Cornwell K, Toner M, Pins GD. The influence of microtextured basal lamina analog topography on keratinocyte function and epidermal organization. ACTA ACUST UNITED AC 2004; 72:47-56. [PMID: 15543632 DOI: 10.1002/jbm.a.30210] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The rational design of future bioengineered skin substitutes requires an understanding of the mechanisms by which the three-dimensional microarchitecture of tissue scaffolds modulates keratinocyte function. Microtextured basal lamina analogs were developed to investigate the relationship between the characteristic topography at the dermal-epidermal interface of native skin and keratinocyte function. Microfabrication techniques were used to create master patterns, negative replicates, and collagen membranes with ridges and channels of length scales (e.g., grooves of 50-200 microm in depth and width) similar to the invaginations found in basal lamina at the dermal-epidermal junction of native skin. Keratinocytes were seeded on the surfaces of basal lamina analogs, and histological analyses were performed after 7 days of tissue culture at the air-liquid interface. The keratinocytes formed a differentiated and stratified epidermis that conformed to the features of the microtextured membranes. Morphometric analyses of immunostained skin equivalents suggest that keratinocyte stratification and differentiation increases as channel depth increases and channel width decreases. This trend was most pronounced in channels with the highest depth-to-width ratios (i.e., 200 microm deep, 50 microm wide). It is anticipated that the findings from these studies will elucidate design parameters to enhance the performance of future bioengineered skin substitutes.
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Affiliation(s)
- Brett R Downing
- Biomedical Engineering Department, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
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Supp DM, Wilson-Landy K, Boyce ST. Human dermal microvascular endothelial cells form vascular analogs in cultured skin substitutes after grafting to athymic mice. FASEB J 2002; 16:797-804. [PMID: 12039861 PMCID: PMC1820617 DOI: 10.1096/fj.01-0868com] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cultured skin substitutes (CSS) consisting of autologous fibroblasts and keratinocytes combined with biopolymers are an adjunctive treatment for large excised burns. CSS containing two cell types are limited by anatomical deficiencies, including lack of a vascular plexus, leading to slower vascularization after grafting than split-thickness autograft. To address this limitation, CSS were prepared containing human keratinocytes, fibroblasts, and dermal microvascular endothelial cells (HDMEC) isolated from a single skin sample. After 16 days in culture, control CSS and CSS containing HDMEC (CSS+EC) were grafted to full-thickness wounds in athymic mice. In CSS+EC in vitro, HDMEC persisted in the dermal substitutes and formed multicellular aggregates. One wk after grafting, HDMEC in CSS+EC organized into multicellular structures, some containing lumens. By 4 wk after grafting, HDMEC were found in linear and circular organizations resembling vascular analogs associated with basement membrane deposition. In some cases, colocalization of HDMEC with mouse perivascular cells was observed. The results demonstrate HDMEC transplantation in a clinically relevant cultured skin model, persistence of HDMEC after grafting, and HDMEC organization into vascular analogs in vitro and in vivo. All cells were derived from the same donor tissue, indicating the feasibility of preparing CSS containing autologous HDMEC for grafting to patients.
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Affiliation(s)
- Dorothy M Supp
- Shriners Hospitals for Children, Cincinnati Burns Hospital, Research Department, and University of Cincinnati College of Medicine, Department of Surgery, Cincinnati, Ohio 45229, USA
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Tjia JS, Moghe PV. Regulation of cell motility on polymer substrates via "dynamic," cell internalizable, ligand microinterfaces. TISSUE ENGINEERING 2002; 8:247-61. [PMID: 12031114 DOI: 10.1089/107632702753725012] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In vivo, motile epidermal tissues frequently encounter ligand microinterfaces that are dynamic, owing to rapid cell-mediated substrate phagocytosis. In this study, we have examined cell motility phenomena in response to the adhesion ligand, collagen, which was presented on cell-internalizable 400-nm colloidal gold microcarriers. Normal human keratinocytes were seeded onto collagen-adsorbed poly(lactide-co-glycolide) (PLGA) films that were predeposited with varying densities of the ligand-associated microcarriers (LAMs), such that the overall ligand density and the ligand loading per microcarrier were invariant. Cells seeded on LAMs exhibited rapid and distinct cytoskeletal redistribution resulting in numerous filopodial extensions, indicative of activation of cell motility processes. We report that the population-averaged cell migration rate of cells, mu, was increased from 2 microm2/min on collagen substrates lacking the microcarriers, to approximately 50 microm2/min on collagen presenting LAMs. An increase in LAM density to 1.2 LAMs per microm2 was found to maximize mu, as well as the directional persistence and speed of cell migration, whereas very high LAM densities saturated cell internalization and diminished migration rates. The cell-LAM interactions essential to enhanced migration were ligand-activated, as mu; values were reduced 400% on internalizable microcarriers lacking ligands; moreover, cooperative ligand elicitation was possible, for example, when 10 microg/mL soluble fibronectin was introduced as a costimulant of keratinocytes, yielding the highest reported mu values (80 microm2/min) on collagen LAM-PLGA substrates. Notably, cell migration rates were severely repressed when cell internalization processes were challenged through covalent conjugation of ligand carriers to the substrate, indicating that signals from cell-LAM binding alone were inadequate for elevated levels of cell migration. Further analysis indicated that the presence of LAMs did not alter the protease-resistant adhesivity between the cell and the underlying substrate, suggesting that the activation governing ligand interactions likely arose at the cell-LAM interface rather than the cell-substrate interface. This study highlights the novel use of secondary ligand-presenting microscale/nanoscale depots at polymer substrates to elicit, via dynamic cell internalization processes, significantly enhanced levels of cell migration over traditional interfaces with ligand-bearing substrates.
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Affiliation(s)
- Jane S Tjia
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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Boyce ST, Warden GD. Principles and practices for treatment of cutaneous wounds with cultured skin substitutes. Am J Surg 2002; 183:445-56. [PMID: 11975935 DOI: 10.1016/s0002-9610(02)00813-9] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Skin substitutes prepared from cultured skin cells and biopolymers may reduce requirements for donor skin autograft, and have been shown to be effective in treatment of excised burns, burn scars, and congenital skin lesions. DATA SOURCES Cultured skin substitutes (CSS) generate skin phenotypes (epidermal barrier, basement membrane) in the laboratory, and restore tissue function and systemic homeostasis. Healed skin is smooth, soft and strong, but develops irregular degrees of pigmentation. Quantitative analysis demonstrates that CSS closes 67 times the area of the donor skin, compared to less than 4 times for split-thickness skin autograft. CONCLUSIONS CSS reduce requirements for donor skin autograft for closure of excised, full-thickness cutaneous wounds, and demonstrate qualitative outcome that is not different from meshed, split-thickness autograft. These results offer reductions in morbidity and mortality for the treatment of burns and chronic wounds, and for cutaneous reconstruction.
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Affiliation(s)
- Steven T Boyce
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio 45229, USA.
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Boyce ST, Supp AP, Swope VB, Warden GD. Vitamin C regulates keratinocyte viability, epidermal barrier, and basement membrane in vitro, and reduces wound contraction after grafting of cultured skin substitutes. J Invest Dermatol 2002; 118:565-72. [PMID: 11918700 DOI: 10.1046/j.1523-1747.2002.01717.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cultured skin substitutes have become useful as adjunctive treatments for excised, full-thickness burns, but no skin substitutes have the anatomy and physiology of native skin. Hypothetically, deficiencies of structure and function may result, in part, from nutritional deficiencies in culture media. To address this hypothesis, vitamin C was titrated at 0.0, 0.01, 0.1, and 1.0 mM in a cultured skin substitute model on filter inserts. Cultured skin substitute inserts were evaluated at 2 and 5 wk for viability by incorporation of 5-bromo-2'-deoxyuridine (BrdU) and by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) conversion. Subsequently, cultured skin substitute grafts consisting of cultured human keratinocytes and fibroblasts attached to collagen-glycosaminoglycan substrates were incubated for 5 wk in media containing 0.0 mM or 0.1 mM vitamin C, and then grafted to athymic mice. Cultured skin substitutes (n = 3 per group) were evaluated in vitro at 2 wk of incubation for collagen IV, collagen VII, and laminin 5, and through 5 wk for epidermal barrier by surface electrical capacitance. Cultured skin substitutes were grafted to full-thickness wounds in athymic mice (n = 8 per group), evaluated for surface electrical capacitance through 6 wk, and scored for percentage original wound area through 8 wk and for HLA-ABC-positive wounds at 8 wk after grafting. The data show that incubation of cultured skin substitutes in medium containing vitamin C results in greater viability (higher BrdU and MTT), more complete basement membrane development at 2 wk, and better epidermal barrier (lower surface electrical capacitance) at 5 wk in vitro. After grafting, cultured skin substitutes with vitamin C developed functional epidermal barrier earlier, had less wound contraction, and had more HLA-positive wounds at 8 wk than without vitamin C. These results suggest that incubation of cultured skin substitutes in medium containing vitamin C extends cellular viability, promotes formation of epidermal barrier in vitro, and promotes engraftment. Improved anatomy and physiology of cultured skin substitutes that result from nutritional factors in culture media may be expected to improve efficacy in treatment of full-thickness skin wounds.
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Affiliation(s)
- Steven T Boyce
- Shriners Hospitals for Children and Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA.
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Gragnani A, Morgan JR, Ferreira LM. Differentiation and barrier formation of a cultured composite skin graft. THE JOURNAL OF BURN CARE & REHABILITATION 2002; 23:126-31. [PMID: 11882802 DOI: 10.1097/00004630-200203000-00009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The differentiation and barrier formation of cultured composite skin grafts (CSGs) were assessed by histology and measurements of surface electrical capacitance (SEC) in vitro and in vivo. Keratinocytes cultured on the surface of acellular dermis were lifted to the air-liquid interface and analyzed for 30 days in vitro. Initially, SEC measurements of CSGs (n = 11) were high but quickly dropped between days 4 and 6 and remained steady for 30 days, indicating barrier formation by the epidermis. Histology of the CSGs (n = 6) demonstrated stratification of the epidermal cells and partial formation of the stratum corneum by day 3 that was complete by day 7. CSGs (n = 5) were transplanted to athymic mice, where they formed a stratified and differentiated epidermis. SEC measurements of CSGs remained low after transplant, suggesting that exposure to the air-liquid interface improved the maturation of CSGs in vitro prior to transplant.
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Erdag G, Morgan JR. Interleukin-1alpha and interleukin-6 enhance the antibacterial properties of cultured composite keratinocyte grafts. Ann Surg 2002; 235:113-24. [PMID: 11753050 PMCID: PMC1422403 DOI: 10.1097/00000658-200201000-00015] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine whether the antibacterial properties of cultured composite keratinocyte grafts can be enhanced by cytokines that stimulate the innate immune response. SUMMARY BACKGROUND DATA Use of composite grafts of cultured keratinocytes has been limited because of their susceptibility to burn wound microorganisms as a result of their lack of a vasculature and immune cells when transplanted. Moreover, use of topical antimicrobial agents is limited with these composite grafts because of cytotoxic effects. Keratinocytes, like all epithelial cells in the body, maintain a natural defense mechanism called the innate immune system. Some components of this system can be induced by cytokines. METHODS The innate immune response of cultured composite keratinocyte grafts treated with various cytokines was assessed indirectly by measuring the levels of mRNA encoding antimicrobial peptides (human beta defensin-1 and -2, LL-37, and antileukoprotease) and antimicrobial proteins (lysozyme, bactericidal/permeability-inducing protein, and phospholipase A2) by reverse transcription-polymerase chain reaction and directly by measuring the ability of keratinocytes to inhibit the growth of added bacteria (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). RESULTS Treatment with interluekin-1alpha increased mRNA levels of antimicrobial peptides in keratinocytes on plastic dishes and in composite grafts. Interleukin-6 increased mRNA levels of antimicrobial proteins in composite grafts only. When added to composite grafts, both cytokines increased antibacterial activity against E. coli, P. aeruginosa, and S. aureus. Moreover, interleukin-1alpha and interleukin-6 did not impair the formation of a differentiated epidermis in vitro or after transplantation of the composite grafts. CONCLUSIONS Treatment with interleukin-1alpha or interleukin-6 of cultured composite keratinocyte grafts stimulates the innate immune response of keratinocytes, enhances the antibacterial properties of these grafts, and may better prepare them to combat infections in contaminated burn wounds.
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Affiliation(s)
- Gulsun Erdag
- Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital and Harvard Medical School, Shriners Hospital for Children, Boston, Massachusetts 02114, USA
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Supp DM, Boyce ST. Overexpression of vascular endothelial growth factor accelerates early vascularization and improves healing of genetically modified cultured skin substitutes. THE JOURNAL OF BURN CARE & REHABILITATION 2002; 23:10-20. [PMID: 11803307 DOI: 10.1097/00004630-200201000-00004] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cultured skin substitutes (CSS) lack a vascular plexus, leading to slower vascularization after grafting than split-thickness skin autograft. CSS containing keratinocytes genetically modified to overexpress vascular endothelial growth factor (VEGF) were previously shown to exhibit enhanced vascularization up to 2 weeks after grafting to athymic mice. The present study examines whether enhanced vascularization compared with controls persists after stable engraftment is achieved and analyzes VEGF expression, wound contraction, and engraftment. Control and VEGF-modified (VEGF+) CSS were grafted onto full-thickness wounds in athymic mice. VEGF expression was detected in VEGF+ CSS 14 weeks after grafting. Graft contraction was significantly lower in VEGF+ CSS compared with controls, suggesting more stable engraftment and better tissue development. Positive HLA-ABC staining, indicating persistence of human cells, was seen in 86.7% (13/15) of grafted VEGF+ CSS, compared with 58.3% (7/12) of controls. Differences in dermal vascularization between control and VEGF+ grafts were significant 1 week after surgery, but not at later times. However, the distribution of vessels was different, with more vessels in the upper dermis of VEGF+ grafts. These results suggest that VEGF overexpression in genetically modified CSS acts to accelerate early graft vascularization and can contribute to improved healing of full-thickness skin wounds.
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Affiliation(s)
- Dorothy M Supp
- The Shriners Hospitals for Children, Cincinnati Burns Hospital, Cincinnati, Ohio 45229, USA
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