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Kheirjou R, Rad JS, Khosroshahi AF, Roshangar L. The useful agent to have an ideal biological scaffold. Cell Tissue Bank 2020; 22:225-239. [PMID: 33222022 DOI: 10.1007/s10561-020-09881-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 11/03/2020] [Indexed: 11/30/2022]
Abstract
Tissue engineering which is applied in regenerative medicine has three basic components: cells, scaffolds and growth factors. This multidisciplinary field can regulate cell behaviors in different conditions using scaffolds and growth factors. Scaffolds perform this regulation with their structural, mechanical, functional and bioinductive properties and growth factors by attaching to and activating their receptors in cells. There are various types of biological extracellular matrix (ECM) and polymeric scaffolds in tissue engineering. Recently, many researchers have turned to using biological ECM rather than polymeric scaffolds because of its safety and growth factors. Therefore, selection the right scaffold with the best properties tailored to clinical use is an ideal way to regulate cell behaviors in order to repair or improve damaged tissue functions in regenerative medicine. In this review we first divided properties of biological scaffold into intrinsic and extrinsic elements and then explain the components of each element. Finally, the types of scaffold storage methods and their advantages and disadvantages are examined.
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Affiliation(s)
- Raziyeh Kheirjou
- Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Jafar Soleimani Rad
- Stem Cell Research Center, Tabriz University of Medical Sciences, 33363879, Tabriz, Iran
| | - Ahad Ferdowsi Khosroshahi
- Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Leila Roshangar
- Stem Cell Research Center, Tabriz University of Medical Sciences, 33363879, Tabriz, Iran.
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Van Der Merwe W, Lind M, Faunø P, Van Egmond K, Zaffagnini S, Marcacci M, Cugat R, Verdonk R, Ibañez E, Guillen P, Marcheggiani Muccioli GM. Xenograft for anterior cruciate ligament reconstruction was associated with high graft processing infection. J Exp Orthop 2020; 7:79. [PMID: 33026544 PMCID: PMC7541808 DOI: 10.1186/s40634-020-00292-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/21/2020] [Indexed: 11/10/2022] Open
Abstract
Purpose To evaluate clinical ad radiological outcomes of anterior cruciate ligament (ACL) reconstruction with an immunochemically modified porcine patellar tendon xenograft controlled against human Achilles tendon allograft at 24-month minimum follow-up. Methods 66 patients undergoing arthroscopic ACL reconstruction were randomized into 2 groups: 34 allografts and 32 xenografts treated to attenuate the host immune response. Follow-up was 24-month minimum. Anterior knee stability was measured as KT − 1000 side-to-side laxity difference (respect to the contralateral healthy knee). Functional performance was assessed by one-legged hop test. Objective manual pivot-shift test and subjective (IKDC, Tegner and SF-36) outcomes were collected. MRI and standard X-Ray were performed. Results 61 subjects (32 allograft, 29 xenograft) were evaluated at 12 and 24 months. Six of the subjects in xenograft group (20.6%) got an infection attributed to a water-based pathogen graft contamination in processing. Intention-to-treat analysis (using the last observation carried forward imputation method) revealed higher KT − 1000 laxity in xenograft group at 24-month follow-up (P = .042). Also pivot-shift was higher in xenograft group at 12-month (P = .015) and 24-month follow-up (P = .038). Per-protocol analysis (missing/contaminated subjects excluded) did not revealed clinical differences between groups. Tibial tunnel widening in the allograft group was low, whereas xenograft tunnel widening was within the expected range of 20–35% as reported in the literature. No immunological reactivity was associated to xenograft group. Conclusions High infection rate (20.6%) was reported in xenograft group. Both groups of patients achieved comparable clinical outcomes if missing/contaminated subjects are excluded. Improved harvesting/processing treatments in future studies using xenografts for ACL reconstruction are needed to reduce infection rate, otherwise xenograft should not be used in ACL reconstruction. Level of evidence Multicenter and double-blinded Randomized Controlled Clinical Trial, Level I.
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Affiliation(s)
| | | | | | - Kees Van Egmond
- Dept. of Orthopaedic Surgery, Isala Klinieken, Zwolle, Netherlands
| | - Stefano Zaffagnini
- IRCCS Istituto Ortopedici Rizzoli, University of Bologna, Lab. Biomeccanica - Via di Barbiano, 1/10, 40137, Bologna, Italy
| | - Maurilio Marcacci
- IRCCS Humanitas University, Milano / former Istituto Ortopedici Rizzoli, University of Bologna, II Clinica Ortopedica, Bologna, Italy
| | - Ramon Cugat
- Hospital Quiron, Artoscopia GC, Barcelona, Spain
| | - Rene Verdonk
- Dept. of Orthopaedic Surgery & Traumatology, Gent Univ. Hospital, Ghent, Belgium
| | - Enrique Ibañez
- Clinica Cemtro, Orthopaedic Surgery & Traumatology, Madrid, Spain
| | - Pedro Guillen
- Clinica Cemtro, Orthopaedic Surgery & Traumatology, Madrid, Spain
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Nürnberger S, Schneider C, van Osch G, Keibl C, Rieder B, Monforte X, Teuschl A, Mühleder S, Holnthoner W, Schädl B, Gahleitner C, Redl H, Wolbank S. Repopulation of an auricular cartilage scaffold, AuriScaff, perforated with an enzyme combination. Acta Biomater 2019; 86:207-222. [PMID: 30590183 DOI: 10.1016/j.actbio.2018.12.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/14/2018] [Accepted: 12/21/2018] [Indexed: 12/21/2022]
Abstract
Biomaterials currently in use for articular cartilage regeneration do not mimic the composition or architecture of hyaline cartilage, leading to the formation of repair tissue with inferior characteristics. In this study we demonstrate the use of "AuriScaff", an enzymatically perforated bovine auricular cartilage scaffold, as a novel biomaterial for repopulation with regenerative cells and for the formation of high-quality hyaline cartilage. AuriScaff features a traversing channel network, generated by selective depletion of elastic fibers, enabling uniform repopulation with therapeutic cells. The complex collagen type II matrix is left intact, as observed by immunohistochemistry, SEM and TEM. The compressive modulus is diminished, but three times higher than in the clinically used collagen type I/III scaffold that served as control. Seeding tests with human articular chondrocytes (hAC) alone and in co-culture with human adipose-derived stromal/stem cells (ASC) confirmed that the network enabled cell migration throughout the scaffold. It also guides collagen alignment along the channels and, due to the generally traverse channel alignment, newly deposited cartilage matrix corresponds with the orientation of collagen within articular cartilage. In an osteochondral plug model, AuriScaff filled the complete defect with compact collagen type II matrix and enabled chondrogenic differentiation inside the channels. Using adult articular chondrocytes from bovine origin (bAC), filling of even deep defects with high-quality hyaline-like cartilage was achieved after 6 weeks in vivo. With its composition and spatial organization, AuriScaff provides an optimal chondrogenic environment for therapeutic cells to treat cartilage defects and is expected to improve long-term outcome by channel-guided repopulation followed by matrix deposition and alignment. STATEMENT OF SIGNIFICANCE: After two decades of tissue engineering for cartilage regeneration, there is still no optimal strategy available to overcome problems such as inconsistent clinical outcome, early and late graft failures. Especially large defects are dependent on biomaterials and their scaffolding, guiding and protective function. Considering the currently used biomaterials, structure and mechanical properties appear to be insufficient to fulfill this task. The novel scaffold developed within this study is the first approach enabling the use of dense cartilage matrix, repopulate it via channels and provide the cells with a compact collagen type II environment. Due to its density, it also provides better mechanical properties than materials currently used in clinics. We therefore think, that the auricular cartilage scaffold (AuriScaff) has a high potential to improve future cartilage regeneration approaches.
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Elder S, Chenault H, Gloth P, Webb K, Recinos R, Wright E, Moran D, Butler J, Borazjani A, Cooley A. Effects of antigen removal on a porcine osteochondral xenograft for articular cartilage repair. J Biomed Mater Res A 2018; 106:2251-2260. [PMID: 29577591 DOI: 10.1002/jbm.a.36411] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/28/2018] [Accepted: 03/15/2018] [Indexed: 11/06/2022]
Abstract
Given the limited availability of fresh osteochondral allografts and uncertainty regarding performance of decellularized allografts, this study was undertaken as part of an effort to develop an osteochondral xenograft for articular cartilage repair. The purpose was to evaluate a simple antigen removal procedure based mainly on treatment with SDS and nucleases. Histology demonstrated a preservation of collagenous structure and removal of most nuclei. Immunohistochemistry revealed the apparent retention of α-Gal within osteocyte lacunae unless the tissue underwent an additional α-galactosidase processing step. Cytoplasmic protein was completely removed as shown by Western blot. Quantitatively, the antigen removal protocol was found to extract approximately 90% of DNA from cartilage and bone, and it extracted over 80% of glycosaminoglycan from cartilage. Collagen content was not affected. Mechanical testing of cartilage and bone were performed separately, in addition to testing the cartilage-bone interface, and the main effect of antigen removal was an increase in cartilage hydraulic permeability. In vivo immunogenicity was assessed by subcutaneous implantation into DBA/1 J mice, and the response was typical of a foreign body rather than immune reaction. Thus, an osteochondral xenograft produced as described has the potential for further development into a treatment for osteochondral lesions in the human knee. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2251-2260, 2018.
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Affiliation(s)
- Steve Elder
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - Hudson Chenault
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - Paul Gloth
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - Katie Webb
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - Ruth Recinos
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - Emily Wright
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - Dalton Moran
- Department of Agricultural and Biological Engineering, James Worth Bagley College of Engineering, Mississippi State University, Starkville, Mississippi
| | - James Butler
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Abdolsamad Borazjani
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
| | - Avery Cooley
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi
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Narayanan G, Bhattacharjee M, Nair LS, Laurencin CT. Musculoskeletal Tissue Regeneration: the Role of the Stem Cells. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2017. [DOI: 10.1007/s40883-017-0036-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Development and Characterization of a Porcine Mitral Valve Scaffold for Tissue Engineering. J Cardiovasc Transl Res 2017; 10:374-390. [PMID: 28462436 DOI: 10.1007/s12265-017-9747-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 04/10/2017] [Indexed: 10/19/2022]
Abstract
Decellularized scaffolds represent a promising alternative for mitral valve (MV) replacement. This work developed and characterized a protocol for the decellularization of whole MVs. Porcine MVs were decellularized with 0.5% (w/v) SDS and 0.5% (w/v) SD and sterilized with 0.1% (v/v) PAA. Decellularized samples were seeded with human foreskin fibroblasts and human adipose-derived stem cells to investigate cellular repopulation and infiltration, and with human colony-forming endothelial cells to investigate collagen IV formation. Histology revealed an acellular scaffold with a generally conserved histoarchitecture, but collagen IV loss. Following decellularization, no significant changes were observed in the hydroxyproline content, but there was a significant reduction in the glycosaminoglycan content. SEM/TEM analysis confirmed cellular removal and loss of some extracellular matrix components. Collagen and elastin were generally preserved. The endothelial cells produced newly formed collagen IV on the non-cytotoxic scaffold. The protocol produced acellular scaffolds with generally preserved histoarchitecture, biochemistry, and biomechanics.
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Stone KR, Walgenbach A, Galili U. Induced Remodeling of Porcine Tendons to Human Anterior Cruciate Ligaments by α-GAL Epitope Removal and Partial Cross-Linking. TISSUE ENGINEERING PART B-REVIEWS 2017; 23:412-419. [PMID: 28068870 PMCID: PMC5567590 DOI: 10.1089/ten.teb.2016.0332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This review describes a novel method developed for processing porcine tendon and other ligament implants that enables in situ remodeling into autologous ligaments in humans. The method differs from methods using extracellular matrices (ECMs) that provide postoperative orthobiological support (i.e., augmentation grafts) for healing of injured ligaments, in that the porcine bone-patellar-tendon-bone itself serves as the graft replacing ruptured anterior cruciate ligament (ACL). The method allows for gradual remodeling of porcine tendon into autologous human ACL while maintaining the biomechanical integrity. The method was first evaluated in a preclinical model of monkeys and subsequently in patients. The method overcomes detrimental effects of the natural anti-Gal antibody and harnesses anti-non-gal antibodies for the remodeling process in two steps: Step 1. Elimination of α-gal epitopes—this epitope that is abundant in pigs (as in other nonprimate mammals) binds the natural anti-Gal antibody, which is the most abundant natural antibody in humans. This interaction, which can induce fast resorption of the porcine implant, is avoided by enzymatic elimination of α-gal epitopes from the implant with recombinant α-galactosidase. Step 2. Partial cross-linking of porcine tendon with glutaraldehyde—this cross-linking generates covalent bonds in the ECM, which slow infiltration of macrophages into the implant. Anti-non-gal antibodies are produced in recipients against the multiple porcine antigenic proteins and proteoglycans because of sequence differences between human and porcine homologous proteins. Anti-non-gal antibodies bind to the implant ECM, recruit macrophages, and induce the implant destruction by directing proteolytic activity of macrophages. Partial cross-linking of the tendon ECM decreases the extent of macrophage infiltration and degradation of the implant and enables concomitant infiltration of fibroblasts that follow the infiltrating macrophages. These fibroblasts align with the implant collagen fibers and secrete their own collagen and other ECM proteins, which gradually remodel the porcine tendon into human ACL. This ligamentization process lasts ∼2 years and the biomechanical integrity of the graft is maintained throughout the whole period. These studies are the first, and so far the only, to demonstrate remodeling of porcine tendon implants into permanently functional autologous ACL in humans.
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Affiliation(s)
- Kevin R Stone
- 1 The Stone Clinic and Foundation , San Francisco, California
| | - Ann Walgenbach
- 1 The Stone Clinic and Foundation , San Francisco, California
| | - Uri Galili
- 2 Department of Surgery, University of Massachusetts Medical School , Worcester, Massachusetts (retired)
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The Development of a Xenograft-Derived Scaffold for Tendon and Ligament Reconstruction Using a Decellularization and Oxidation Protocol. Arthroscopy 2017; 33:374-386. [PMID: 27692557 DOI: 10.1016/j.arthro.2016.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 06/29/2016] [Accepted: 07/11/2016] [Indexed: 02/02/2023]
Abstract
PURPOSE To evaluate the biological, immunological, and biomechanical properties of a scaffold derived by architectural modification of a fresh-frozen porcine patella tendon using a decellularization protocol that combines physical, chemical, and enzymatic modalities. METHODS Porcine patellar tendons were processed using a decellularization and oxidation protocol that combines physical, chemical, and enzymatic modalities. Scaffolds (n = 88) were compared with native tendons (n = 70) using histologic, structural (scanning electron microscopy, porosimetry, and tensile testing), biochemical (mass spectrometry, peracetic acid reduction, DNA quantification, alpha-galactosidase [α-gal] content), as well as in vitro immunologic (cytocompatibility, cytokine induction) and in vivo immunologic nonhuman primate analyses. RESULTS A decrease in cellularity based on histology and a significant decrease in DNA content were observed in the scaffolds compared with the native tendon (P < .001). Porosity and pore size were increased significantly (P < .001). Scaffolds were cytocompatible in vitro. There was no difference between native tendons and scaffolds when comparing ultimate tensile load, stiffness, and elastic modulus. The α-gal xenoantigen level was significantly lower in the decellularized scaffold group compared with fresh-frozen, nondecellularized tissue (P < .001). The in vivo immunological response to implanted scaffolds measured by tumor necrosis factor-α and interleukin-6 levels was significantly (P < .001) reduced compared with untreated controls in vitro. These results were confirmed by an attenuated response to scaffolds in vivo after implantation in a nonhuman primate model. CONCLUSIONS Porcine tendon was processed via a method of decellularization and oxidation to produce a scaffold that possessed significantly less inflammatory potential than a native tendon, was biocompatible in vitro, of increased porosity, and with significantly reduced amounts of α-gal epitope while retaining tensile properties. CLINICAL RELEVANCE Porcine-derived scaffolds may provide a readily available source of material for musculoskeletal reconstruction and repair while eliminating concerns regarding disease transmission and the morbidity of autologous harvest.
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Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, Roberti Di Sarsina T, Raggi F, Benzi A, Marcacci M. Anterior cruciate ligament reconstruction with a novel porcine xenograft: the initial Italian experience. JOINTS 2015; 3:85-90. [PMID: 26605257 DOI: 10.11138/jts/2015.3.2.085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
At the current state of the art in anterior cruciate ligament (ACL) reconstruction, multiple techniques have been presented but none has given clearly defined and improved results. One of the main issues concerns the choice of graft. The concept of using xenograft tissue, defined as a graft tissue from one species and destined for implantation in an unlike species, was introduced in order to try to overcome the mechanical and biological concerns associated with synthetic materials and the safety and quality concerns and availability problems of allograft tissue. Xenograft tissue carries the risk of producing an immunological reaction. In order to try to overcome or attenuate the immune response against porcine xenograft tissue, the Z-Process® (Aperion Biologics Inc, San Antonio, Texas, USA) has been developed and used to produce the Z-Lig® family of devices for ACL reconstruction procedures. Z-Lig® is a tendon graft with or without bone blocks, sourced from animal tissue in a manner consistent with what has normally been sourced from human tissue, and processed to overcome anti-Gal-mediated rejection and to attenuate other immunological recognition in humans. All this while ensuring sterility, viral inactivation and preservation of mechanical proprieties appropriate for an ACL reconstruction device. The Z-Lig® device has been tested in skeletally mature monkeys and given interesting and promising results from the preclinical performance and safety profile point of view. On this basis, it was possible to proceed with the first clinical trial involving humans, which gave similar encouraging results. The Z-Lig® device has also been implanted in Italy at the Rizzoli Orthopaedic Institute in Bologna, as a part of international multicenter prospective randomized blinded controlled study aimed at comparing xenograft with allograft tissue.
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Affiliation(s)
- Stefano Zaffagnini
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Alberto Grassi
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Giulio Maria Marcheggiani Muccioli
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Tommaso Roberti Di Sarsina
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Federico Raggi
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Andrea Benzi
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Maurilio Marcacci
- The II Orthopaedic and Traumatology Clinic, Biomechanics Laboratory and Technological Innovation, Rizzoli Orthopaedic Institute, Bologna, Italy
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Galili U. Avoiding Detrimental Human Immune Response Against Mammalian Extracellular Matrix Implants. TISSUE ENGINEERING PART B-REVIEWS 2015; 21:231-41. [DOI: 10.1089/ten.teb.2014.0392] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Uri Galili
- Department of Surgery, University of Massachusetts Medical School, Worcester, Massachusetts
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11
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Kim MS, Jeong S, Lim HG, Kim YJ. Differences in xenoreactive immune response and patterns of calcification of porcine and bovine tissues in α-Gal knock-out and wild-type mouse implantation models. Eur J Cardiothorac Surg 2014; 48:392-9. [DOI: 10.1093/ejcts/ezu501] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 11/19/2014] [Indexed: 11/14/2022] Open
Affiliation(s)
- Min-Seok Kim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea
| | - Saeromi Jeong
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea
| | - Hong-Gook Lim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea
| | - Yong Jin Kim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea
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12
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Therapeutic Strategies for Xenotransplantation. Xenotransplantation 2014. [DOI: 10.1128/9781555818043.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Park MS, Kim TG, Lee KM, Chung CY, Kwon SS, Yoon IH, Park CG. Effects of reduction in the alpha-gal antigen on bony union: a model of xenobone graft using GalT knockout mouse. Xenotransplantation 2014; 21:267-73. [PMID: 24635119 DOI: 10.1111/xen.12092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/05/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Among the bone graft sources used currently, the availability of autografts is limited and allografts are expensive. Therefore, xenobone grafts have drawn attention as a new source of bone grafts, although immunologic rejection issues are unresolved. This study used a GalT knockout mouse model to investigate the effects of reducing the alpha-gal epitope using alpha-galactosidase on the union of porcine xenobone grafts. METHODS Sixty-eight alpha-gal knockout C57/BL6 mice and eight wild-type mice were used. The mice were divided into five groups: In group 1 (26 alpha-gal knockout mice), an alpha-galactosidase-treated porcine xenograft was transplanted into the mouse femur to reduce antigenicity, and intramedullary fixation was performed. In group 2 (26 alpha-gal knockout mice), a non-treated porcine xenobone graft was performed. In group 3 (eight alpha-gal knockout C57/BL6 mice), syngenic bone grafts were performed. In group 4 (eight wild-type C57/BL6 mice), syngenic bone grafts were performed. In group 5 (eight C57/BL6 alpha-gal knockout mice), a bone defect model was obtained by maintaining the gap of the osteotomy site. Groups 3, 4, and 5 were used for positive and negative control groups. Qualitative immunohistochemical analysis of the porcine bone was performed to detect the presence of the alpha-gal epitope in groups 1 and 2. The concentration of the anti-alpha-gal antibody was evaluated using a quantitative enzyme-linked immunosorbent assay (ELISA) at the time of sacrifice (3, 4, and 5 weeks after the operation). Histologic and radiologic results (Goldberg method) for the bone union were compared. RESULTS The qualitative immunohistochemical analysis showed that the alpha-gal epitope was reduced when xenobone grafts were treated with alpha-galactosidase. Compared with group 2, group 1 showed a low anti-alpha-gal antibody concentration in the ELISA results. In group 2, the anti-alpha-gal antibody concentration increased with time. Group 1 showed significantly better histologic union than group 2, but the amount of radiologic union was similar in the two groups. CONCLUSIONS Alpha-galactosidase treatment of a porcine xenobone graft can reduce the alpha-gal epitope. This reduction in the antigen could significantly reduce the humoral immune response to the alpha-gal antigen in C57/BL6 alpha-gal knockout mice, leading to significant improvements in histologic union. This study provides a relevant GalT knockout mouse model for detecting the effects of alpha-gal epitope reduction by alpha-galactosidase on the union of porcine xenobone grafts.
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Affiliation(s)
- Moon Seok Park
- Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea
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14
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Cissell DD, Hu JC, Griffiths LG, Athanasiou KA. Antigen removal for the production of biomechanically functional, xenogeneic tissue grafts. J Biomech 2013; 47:1987-96. [PMID: 24268315 DOI: 10.1016/j.jbiomech.2013.10.041] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/16/2013] [Accepted: 10/19/2013] [Indexed: 10/26/2022]
Abstract
Xenogeneic tissues are derived from other animal species and provide a source of material for engineering mechanically functional tissue grafts, such as heart valves, tendons, ligaments, and cartilage. Xenogeneic tissues, however, contain molecules, known as antigens, which invoke an immune reaction following implantation into a patient. Therefore, it is necessary to remove the antigens from a xenogeneic tissue to prevent immune rejection of the graft. Antigen removal can be accomplished by treating a tissue with solutions and/or physical processes that disrupt cells and solubilize, degrade, or mask antigens. However, processes used for cell and antigen removal from tissues often have deleterious effects on the extracellular matrix (ECM) of the tissue, rendering the tissue unsuitable for implantation due to poor mechanical properties. Thus, the goal of an antigen removal process should be to reduce the antigen content of a xenogeneic tissue while preserving its mechanical functionality. To expand the clinical use of antigen-removed xenogeneic tissues as biomechanically functional grafts, it is essential that researchers examine tissue antigen content, ECM composition and architecture, and mechanical properties as new antigen removal processes are developed.
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Affiliation(s)
- Derek D Cissell
- Department of Orthopaedic Surgery, University of California, Davis, CA, USA; Department of Surgical and Radiological Sciences, University of California, Davis, CA, USA
| | - Jerry C Hu
- Department of Biomedical Engineering, University of California, Davis, CA, USA
| | - Leigh G Griffiths
- Department of Veterinary Medicine: Medicine and Epidemiology, University of California, Davis, CA, USA
| | - Kyriacos A Athanasiou
- Department of Biomedical Engineering, University of California, Davis, CA, USA; Department of Orthopaedic Surgery, University of California, Davis, CA, USA.
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Lim HG, Choi SY, Yoon EJ, Kim SH, Kim YJ. In VivoEfficacy of Alpha-Galactosidase as Possible Promise for Prolonged Durability of Bioprosthetic Heart Valve Using Alpha1,3-Galactosyltransferase Knockout Mouse. Tissue Eng Part A 2013; 19:2339-48. [DOI: 10.1089/ten.tea.2013.0062] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hong-Gook Lim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sun Young Choi
- Seoul National University Hospital Clinical Research Institute, Xenotransplantation Research Center, Seoul, Republic of Korea
| | - Eun Jung Yoon
- Seoul National University Hospital Clinical Research Institute, Xenotransplantation Research Center, Seoul, Republic of Korea
| | - Soo Hwan Kim
- Seoul National University Hospital Clinical Research Institute, Xenotransplantation Research Center, Seoul, Republic of Korea
| | - Yong Jin Kim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Republic of Korea
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Hasan J, Fisher J, Ingham E. Current strategies in meniscal regeneration. J Biomed Mater Res B Appl Biomater 2013; 102:619-34. [PMID: 24030973 DOI: 10.1002/jbm.b.33030] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/13/2013] [Accepted: 08/18/2013] [Indexed: 12/26/2022]
Abstract
The meniscus plays an important role in the biomechanics and tribology of the knee joint. Damage to or disease of the meniscus is now recognized to predispose to the development of osteoarthritis. Treatment of meniscal injury through arthroscopic surgery has become one of the most common orthopedic surgical procedures, and in the United States this can represent 10 to 20% of procedures related to the knee. The meniscus has a limited healing capacity constrained to the vascularized periphery and therefore, surgical repair of the avascular regions is not always feasible. Replacement and repair of the meniscus to treat injuries is being investigated using tissue engineering strategies. Promising as these approaches may be, there are, however, major barriers to overcome before translation to the clinic.
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Affiliation(s)
- Jahid Hasan
- Institute of Medical and Biological Engineering, Schools of Biomedical Sciences and Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK
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17
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Rowland CR, Little D, Guilak F. Factors influencing the long-term behavior of extracellular matrix-derived scaffolds for musculoskeletal soft tissue repair. J Long Term Eff Med Implants 2013; 22:181-93. [PMID: 23582110 DOI: 10.1615/jlongtermeffmedimplants.2013006120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Musculoskeletal connective tissues such as tendon, ligament, and cartilage possess a limited ability for self-repair. Tissue engineering seeks to use combinations of cells, bioactive molecules, and biomaterials to develop new treatment options for the repair or replacement of damaged tissues. The use of native extracellular matrix as scaffold material for tissue engineering has become increasingly attractive because such tissues can not only provide structural support, but also regulate cell behavior. Although demineralized bone matrix has long been recognized for its osteoinductive abilities, recent studies have identified the ability of cartilage and tendon extracellular matrices to stimulate the differentiation of mesenchymal or adipose-derived adult stem cells toward chondrogenic or tenogenic lineages, respectively. This review discusses the motivation for fabricating scaffolds from musculoskeletal tissues, the in vitro and in vivo efficacy of these tissue-derived scaffolds, and various processing techniques such as decellularization or cross-linking that can mitigate immunogenic responses, moderate the degradation profile, and enhance the mechanical properties of these constructs following long-term implantation in vivo.
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Affiliation(s)
- Christopher R Rowland
- Department of Orthopaedic Surgery and Biomedical Engineering, Duke University Medical Center, Durham, NC 27710, USA
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18
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Linz LA, Burke LH, Miller LA. Two cross-linked porcine dermal implants in a single patient undergoing hernia repair. BMJ Case Rep 2013; 2013:bcr-2012-007562. [PMID: 23345480 DOI: 10.1136/bcr-2012-007562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A 50-year-old woman with a history of multiple recurrent incisional hernias and multiple comorbidities received two different porcine dermal implants during the same procedure due to the availability of products in stock. At 3.5 months following this procedure, the patient developed a secondary hernia inferior and lateral to the site of previous surgery. Both the implants were biopsied and sent for pathological evaluation. One implant was compliant and well integrated while the other was non-compliant and exhibited extensive foreign body reaction. In this case report, we examine the differences between the two porcine implants that may have caused them to react so differently in the same subject under the same conditions.
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Affiliation(s)
- Luke A Linz
- College of Osteopathic Medicine, Michigan State University, Lansing, Michigan, USA
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19
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Schwarz S, Koerber L, Elsaesser AF, Goldberg-Bockhorn E, Seitz AM, Dürselen L, Ignatius A, Walther P, Breiter R, Rotter N. Decellularized cartilage matrix as a novel biomatrix for cartilage tissue-engineering applications. Tissue Eng Part A 2012; 18:2195-209. [PMID: 22690787 DOI: 10.1089/ten.tea.2011.0705] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Damage of cartilage structures in the head and neck region as well as in orthopedic sites are frequently caused by trauma, tumor resection, or congenital defects. Despite a high demand in many clinical fields, until today, no adequate cartilage replacement matrix is available for these fields of application. Materials that are clinically applied for joint cartilage repair still need optimization due to difficult intraoperative handling and risk of early mechanical damage. We have developed and applied a novel chemical process to completely decellularize and sterilize human and porcine cartilage tissues (meniscus cartilage and nasal septum) to generate a new type of bioimplant matrix. To characterize this matrix and to determine the effect of the decellularization process, the content of denatured collagen (w(D)) and the content of glycosaminoglycans (GAGs) (w(G)) were determined. Possible cytotoxic effects and cellular compatibility of the matrix in vitro have been examined by seeding processed cartilage biomatrices with human primary chondrocytes as well as murine fibroblasts (L929). Vitality and state of metabolism of cells were measured using MTS assays. Both cell types adhered to scaffold surfaces and proliferated. No areas of growth inhibition or cytotoxic effects were detected. New synthesis of cartilage-specific extracellular matrix was observed. By histological staining, electron microscopy, and μCT analysis, an increase of matrix porosity, complete cell elimination, and high GAG removal were demonstrated. Being from natural-origin, processed xenogenic and allogeneic cartilage biomatrices are highly versatile with regard to shape, size, and biomechanics, making them promising candidates for various biomedical applications.
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Affiliation(s)
- Silke Schwarz
- Department of Otorhinolaryngology, Ulm University Medical Center, Ulm, Germany.
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20
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Sommaggio R, Cohnen A, Watzl C, Costa C. Multiple receptors trigger human NK cell-mediated cytotoxicity against porcine chondrocytes. THE JOURNAL OF IMMUNOLOGY 2012; 188:2075-83. [PMID: 22287712 DOI: 10.4049/jimmunol.1100433] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Xenotransplantation of genetically engineered porcine chondrocytes may provide a therapeutic solution for the repair of cartilage defects of various types. However, the mechanisms underlying the humoral and cellular responses that lead to rejection of xenogeneic cartilage are not well understood. In this study, we investigated the interaction between human NK cells and isolated porcine costal chondrocytes (PCC). Our data show that freshly isolated NK cells adhere weakly to PCC. Consequently, PCC were highly resistant to cytolysis mediated by freshly isolated NK cells. However, the presence of human natural Abs in the coculture was often sufficient to trigger cytotoxicity against PCC. Furthermore, IL-2 stimulation of NK cells or activation of PCC with the proinflammatory cytokines TNF-α or IL-1α resulted in increased adhesion, which was paralleled by increased NK cell-mediated lysis of PCC. NK cell adhesion to PCC could be blocked by Abs against human LFA-1 and porcine VCAM-1. NKG2D and NKp44 were involved in triggering cytotoxicity against PCC, which expressed ligands for these activating NK cell receptors. Our data further suggest that NKp30 and NKp46 may contribute to the activation of NK cells by PCC under certain conditions. Finally, comparative studies confirmed that PCC are more resistant than porcine aortic endothelial cells to human NK cell-mediated lysis. Thus, the data demonstrate that human NK cells can kill pig chondrocytes and may therefore contribute to rejection of xenogeneic cartilage. In addition, we identify potential targets for intervention to prevent the NK cell response against pig xenografts.
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Affiliation(s)
- Roberta Sommaggio
- New Therapies of Genes and Transplants Group, Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona 08908, Spain
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Lee C, Ahn H, Kim SH, Choi SY, Kim YJ. Immune response to bovine pericardium implanted into α1,3-galactosyltransferase knockout mice: feasibility as an animal model for testing efficacy of anticalcification treatments of xenografts. Eur J Cardiothorac Surg 2012; 42:164-72. [PMID: 22223697 DOI: 10.1093/ejcts/ezr260] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Glutaraldehyde (GA)-fixed xenografts are prone to calcification after implantation in humans and there is evidence that immune reaction to the Galα1,3-Galβ1,4GlcNAc-R (α-Gal) antigen may play a part in this process. The objectives of this study were to evaluate the immune response of α1,3-galactosyltransferase knockout (α-Gal KO) mice to bovine pericardium and to evaluate the effect of various anticalcification treatments on bovine pericardium using mouse subcutaneous implantation model. METHODS Bovine pericardial tissues were divided into eight groups according to the method of anticalcification treatments. Prepared tissues were subcutaneously implanted into the α-Gal KO and wild-type mice for 2 months, and anti-α-Gal antibodies were measured at 2 weeks and 2 months after implantation. Explanted tissues were examined by immunohistochemistry and calcium contents of the explanted tissues were measured. RESULTS Titres of IgM and IgG antibodies in the α-Gal KO mice increased significantly according to the duration of implantation, whereas titres of IgM and IgG antibodies in the wild-type mice increased until 2 weeks after implantation without further increase thereafter. Titres of IgG antibodies measured at 2 months after implantation were significantly higher in the α-Gal KO mice than in the wild-type mice. Immunohistochemistry revealed macrophages surrounding the pericardial tissues irrespective of the mouse type into which the tissues implanted, whereas T-cells could only be observed in the tissues implanted into the α-Gal KO mice. Except the high-concentration GA-treated group, calcium contents of anticalcification-treated groups were all significantly lower or tended to be lower than that of the control group, irrespective of the mouse type. Calcium contents of the control group were significantly higher in the α-Gal KO mice than in the wild-type mice. CONCLUSIONS Bovine pericardium implanted into the α-Gal KO mice caused significant increase in anti-α-Gal antibodies, showed some histologic evidences of chronic rejection and revealed a potential toward more calcification. These findings suggest a possible role of immune response in calcification of xenografts. High-concentration GA fixation alone did not prove to be an effective anticalcification treatment in mouse subcutaneous implantation model. α-Gal KO mouse subcutaneous implantation model might be a feasible animal model for testing efficacy of anticalcification treatments incorporating immunologic approach.
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Affiliation(s)
- Cheul Lee
- Department of Thoracic and Cardiovascular Surgery, Cardiovascular Center, Sejong General Hospital, Bucheon, Republic of Korea
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22
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Pei M, Yan Z, Shoukry M, Boyce BM. Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects. J Orthop Res 2010; 28:1064-70. [PMID: 20140938 DOI: 10.1002/jor.21096] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The use of xenogeneic tissues offers many advantages with respect to availability, quality control, and timing of tissue harvest. Our previous study indicated that implantation of premature tissue constructs from allogeneic synovium-derived stem cells (SDSCs) facilitated cartilage tissue regeneration. The present study investigated the feasibility of xenoimplantation of SDSC-based premature tissue constructs for the repair of osteochondral defects. Porcine SDSCs were mixed with fibrin gel, seeded in polyglycolic acid (PGA) scaffolds, and cultured in a rotating bioreactor system supplemented for 1 month with growth factor cocktails. The engineered porcine premature tissues were implanted to repair surgically induced osteochondral defects in the medial femoral condyles of 12 rabbits. Three weeks after surgery, the xenoimplantation group exhibited a smooth, whitish surface while the untreated control remained empty. Surprisingly, 6 months after surgery, the xenoimplantation group displayed some tissue loss while the untreated control group was overgrown with fibrocartilage tissue. In the xenoimplantation group, chronic inflammation was observed in synovial tissue where porcine major histocompatibility complex (MHC) class II antigen positively stained in the engulfed foreign bodies. In addition, porcine source cells also migrated from the implantation site and may have been responsible for the observed loss of glycosaminoglycans (GAGs) underneath surrounding articular cartilage. The histological score was much worse in the xenoimplanted group than in the untreated control. Our study suggested that SDSC-based xenogeneic tissue constructs might cause delayed immune rejection. Xenotransplantation may not be an appropriate approach to repair osteochondral defects.
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Affiliation(s)
- Ming Pei
- Stem Cell and Tissue Engineering Laboratory, Department of Orthopaedics, West Virginia University, P.O. Box 9196, One Medical Center Drive, Morgantown, West Virginia 26506-9196, USA.
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23
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Lima EG, Tan AR, Tai T, Marra KG, DeFail A, Ateshian GA, Hung CT. Genipin enhances the mechanical properties of tissue-engineered cartilage and protects against inflammatory degradation when used as a medium supplement. J Biomed Mater Res A 2010; 91:692-700. [PMID: 19025982 DOI: 10.1002/jbm.a.32305] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genipin is a naturally-derived biocompatible cross-linking agent commonly used to generate three dimensional tissue-engineered scaffolds or to fix biologically derived scaffolds prior to implantation. Here we propose a novel use for genipin as a long-term culture medium supplement to promote cross-linking of de novo cell products that are produced in engineered cartilage. We hypothesize that the application of genipin will stabilize the extracellular matrix components and increase the mechanical properties of developing engineered cartilage. Chondrocytes encapsulated in agarose hydrogel (a neutrally charged polysaccharide scaffold that is unaffected by genipin cross-linking) were cultured in a chemically-defined growth medium that was supplemented with varying concentrations of genipin (22 microM, 220 microM, 2200 microM) for various durations (continuous or intermittent). Tissues developed significantly higher mechanical properties (+28% dynamic modulus and +20% Young's modulus) by day 42 with genipin treatment compared to untreated controls. These increases were not immediate, but presented over culture time after genipin treatment. The genipin treated groups were also more resistant to cytokine-induced degradation with interleukin-1alpha; maintaining an E(Y) (+218%), G* (+390%) and glycosaminoglycan (GAG) content (+477%) over genipin-untreated constructs subjected to interleukin. We hypothesize two mechanisms through which the physical enhancement of tissue properties may be fostered: (1) by cross-link mediated reorganization and enhanced retention of cell-elaborated extracellular matrix components, and (2) through reduction of the loss of extracellular matrix components by increasing their resilience to catabolic degradation. These studies demonstrate a potential use of genipin as a medium supplement to develop enhanced engineered cartilage.
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Affiliation(s)
- Eric G Lima
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA
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24
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Arnoczky SP, Cook JL, Carter T, Turner AS. Translational Models for Studying Meniscal Repair and Replacement: What They Can and Cannot Tell Us. TISSUE ENGINEERING PART B-REVIEWS 2010; 16:31-9. [DOI: 10.1089/ten.teb.2009.0428] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Steven P. Arnoczky
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - James L. Cook
- Comparative Orthopaedic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | | | - A. Simon Turner
- Small Ruminant Comparative Orthopaedic Research Laboratory, Veterinary Medical Center, Colorado State University, Fort Collins, Colorado
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25
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Xu H, Wan H, Zuo W, Sun W, Owens RT, Harper JR, Ayares DL, McQuillan DJ. A porcine-derived acellular dermal scaffold that supports soft tissue regeneration: removal of terminal galactose-alpha-(1,3)-galactose and retention of matrix structure. Tissue Eng Part A 2009; 15:1807-19. [PMID: 19196142 DOI: 10.1089/ten.tea.2008.0384] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sub-optimal clinical outcomes after implantation of animal-derived tissue matrices may be attributed to the nature of the processing of the material or to an immune response elicited in response to xenogeneic epitopes. The ability to produce a porcine-derived graft that retains the structural integrity of the extracellular matrix and minimizes potential antigenic response to galactose-alpha-(1,3)-galactose terminal disaccharide (alpha-Gal) may allow the scaffold to support regeneration of native tissue. Dermal tissue from wild-type (WT-porcine-derived acellular dermal matrix [PADM]) or Gal-deficient (Gal(-/-) PADM) pigs was processed to remove cells and DNA while preserving the structural integrity of the extracellular matrix. In addition, the WT tissue was subjected to an enzymatic treatment to minimize the presence of alpha-Gal (Gal-reduced PADM). Extracellular matrix composition and integrity was assessed by histological, immunohistochemical (IHC), and ultrastructural analysis. In vivo performance was evaluated by implantation into the abdominal wall of Old World primates in an exisional repair model. Anti-alpha-Gal activity in the serum of monkeys implanted subcutaneously was assessed by ELISA. Minimal modification to the extracellular matrix was assessed by evaluation of intact structure as demonstrated by staining patterns for type I and type VII collagens, laminin, and fibronectin similar to native porcine skin tissues. Explants from the abdominal wall showed evidence of remodeling, notably fibroblast cell repopulation and revascularization, as early as 1 month. Serum ELISA revealed an initial anti-alpha-Gal induction that decreased to baseline levels over time in the primates implanted with WT-PADM, whereas no or minimal anti-Gal activity was detected in the primates implanted with Gal(-/-) PADM or Gal-reduced PADM. The combination of a nondamaging process, successful removal of cells, and reduction of xenogeneic alpha-Gal antigens from the porcine dermal matrix are critical for producing a material with the ability to remodel and integrate into host tissue and ultimately support soft tissue regeneration.
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Affiliation(s)
- Hui Xu
- Research Department, LifeCell Corporation, Branchburg, NJ 08876, USA.
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26
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27
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Sandor M, Xu H, Connor J, Lombardi J, Harper JR, Silverman RP, McQuillan DJ. Host Response to Implanted Porcine-Derived Biologic Materials in a Primate Model of Abdominal Wall Repair. Tissue Eng Part A 2008; 14:2021-31. [DOI: 10.1089/ten.tea.2007.0317] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Hui Xu
- LifeCell Corporation, Branchburg, New Jersey
| | | | | | | | - Ronald P. Silverman
- Division of Plastic Surgery, University of Maryland School of Medicine, Baltimore, Maryland
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28
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Supronowicz P, Zhukauskas R, York-Ely A, Wicomb W, Thula T, Fleming L, Cobb RR. Immunologic analyses of bovine bone treated with a novel tissue sterilization process. Xenotransplantation 2008; 15:398-406. [DOI: 10.1111/j.1399-3089.2008.00502.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Kiernan K, Harnden I, Gunthart M, Gregory C, Meisner J, Kearns-Jonker M. The anti-non-gal xenoantibody response to xenoantigens on gal knockout pig cells is encoded by a restricted number of germline progenitors. Am J Transplant 2008; 8:1829-39. [PMID: 18671678 PMCID: PMC3462011 DOI: 10.1111/j.1600-6143.2008.02337.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Antibodies directed at non-gal xenoantigens are responsible for acute humoral xenograft rejection when gal knockout (GalTKO) pig organs are transplanted into nonhuman primates. We generated IgM and IgG gene libraries using peripheral blood lymphocytes of rhesus monkeys initiating active xenoantibody responses after immunization with GalTKO pig endothelial cells and used these libraries to identify IgV(H) genes that encode antibody responses to non-gal pig xenoantigens. Immunoglobulin genes derived from the IGHV3-21 germline progenitor encode xenoantibodies directed at non-gal xenoantigens. Transduction of GalTKO cells with lentiviral vectors expressing the porcine alpha1,3 galactosyltransferase gene responsible for gal carbohydrate expression results in a higher level of binding of 'anti-non-gal' xenoantibodies to transduced GalTKO cells expressing the gal carbohydrate, suggesting that anti-non-gal xenoantibodies cross react with carbohydrate xenoantigens. The galactosyltransferase two gene encoding isoglobotriaosylceramide synthase (iGb3 synthase) is not expressed in GalTKO pig cells. Our results demonstrate that anti-non-gal xenoantibodies in primates are encoded by IgV(H) genes that are restricted to IGHV3-21 and bind to an epitope that is structurally related to but distinct from the Gal carbohydrate.
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Affiliation(s)
- Kathleen Kiernan
- Department of Cardiothoracic Surgery Saban Research Institute of the Childrens Hospital of Los Angeles,University of Southern California Keck School of Medicine 4650 Sunset Blvd, Mailstop #137, Los Angeles, CA 90027
| | - Ivan Harnden
- Department of Cardiothoracic Surgery Saban Research Institute of the Childrens Hospital of Los Angeles,University of Southern California Keck School of Medicine 4650 Sunset Blvd, Mailstop #137, Los Angeles, CA 90027
| | - Mirja Gunthart
- Department of Cardiothoracic Surgery Saban Research Institute of the Childrens Hospital of Los Angeles
| | - Clare Gregory
- Department of Surgical and Radiological Sciences, University of California, Davis School of Veterinary Medicine, Davis, CA. 95616
| | - Jessica Meisner
- Department of Cardiothoracic Surgery Saban Research Institute of the Childrens Hospital of Los Angeles,University of Southern California Keck School of Medicine 4650 Sunset Blvd, Mailstop #137, Los Angeles, CA 90027
| | - Mary Kearns-Jonker
- Department of Cardiothoracic Surgery Saban Research Institute of the Childrens Hospital of Los Angeles,University of Southern California Keck School of Medicine 4650 Sunset Blvd, Mailstop #137, Los Angeles, CA 90027
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30
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Benatuil L, Kaye J, Cretin N, Godwin JG, Cariappa A, Pillai S, Iacomini J. Ig knock-in mice producing anti-carbohydrate antibodies: breakthrough of B cells producing low affinity anti-self antibodies. THE JOURNAL OF IMMUNOLOGY 2008; 180:3839-48. [PMID: 18322191 DOI: 10.4049/jimmunol.180.6.3839] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Natural Abs specific for the carbohydrate Ag Galalpha1-3Galbeta1-4GlcNAc-R (alphaGal) play an important role in providing protective host immunity to various pathogens; yet little is known about how production of these or other anti-carbohydrate natural Abs is regulated. In this study, we describe the generation of Ig knock-in mice carrying functionally rearranged H chain and L chain variable region genes isolated from a B cell hybridoma producing alphaGal-specific IgM Ab that make it possible to examine the development of B cells producing anti-carbohydrate natural Abs in the presence or absence of alphaGal as a self-Ag. Knock-in mice on a alphaGal-deficient background spontaneously developed alphaGal-specific IgM Abs of a sufficiently high titer to mediate rejection of alphaGal expressing cardiac transplants. In the spleen of these mice, B cells expressing alphaGal-specific IgM are located in the marginal zone. In knock-in mice that express alphaGal, B cells expressing the knocked in BCR undergo negative selection via receptor editing. Interestingly, production of low affinity alphaGal-specific Ab was observed in mice that express alphaGal that carry two copies of the knocked in H chain. We suggest that in these mice, receptor editing functioned to lower the affinity for self-Ag below a threshold that would result in overt pathology, while allowing development of low affinity anti-self Abs.
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Affiliation(s)
- Lorenzo Benatuil
- Transplantation Research Center, Brigham and Women's Hospital, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA
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Abstract
Cartilage engineering is the object of intense research as a result of major medical needs and therapeutic prospects. Porcine xenogeneic cells/tissues may help in the development of clinical applications such as articular cartilage repair. However, unmodified porcine cartilage is rejected in primates by humoral and cellular mechanisms. We previously showed that porcine articular chondrocytes (PAC) isolated from H-transferase (HT) transgenic pigs show markedly reduced expression of the Galalpha1,3Gal antigen (alphaGal) and prolonged survival when transplanted into alpha1,3galactosyltransferase-deficient mice. In this work, we further studied the protective mechanisms of HT transgenic expression in cartilage, particularly its effects on monocyte adhesion. To this end, PAC isolated from control and HT transgenic pigs were assayed for human complement deposition and adhesion to the human monoblastic cell line U937. Consistent with a reduction in complement activation by the classical pathway, the HT transgenic PAC showed a 2-fold reduction in the deposition of complement components C4 and C3 relative to controls. Adhesion of U937 cells to HT PAC was also diminished under various conditions. This reduction was more dramatic at high effector:target ratios and especially observed when combined with anti-alphaGal antibodies (5-fold difference). Nevertheless, this effect was also observed in the absence of anti-alphaGal. antibodies and after tumor necrosis factor treatment. These results suggest that HT expression on porcine chondrocytes protects them from both humoral and cellular rejection.
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Affiliation(s)
- C Costa
- Department of Molecular Sciences, Alexion Pharmaceuticals, Inc, Cheshire, Connecticut, USA.
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32
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The Galalpha1,3Galbeta1,4GlcNAc-R (alpha-Gal) epitope: a carbohydrate of unique evolution and clinical relevance. Biochim Biophys Acta Gen Subj 2007; 1780:75-88. [PMID: 18047841 DOI: 10.1016/j.bbagen.2007.11.003] [Citation(s) in RCA: 294] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 11/10/2007] [Accepted: 11/13/2007] [Indexed: 11/22/2022]
Abstract
In 1985, we reported that a naturally occurring human antibody (anti-Gal), produced as the most abundant antibody (1% of immunoglobulins) throughout the life of all individuals, recognizes a carbohydrate epitope Galalpha1-3Galbeta1-4GlcNAc-R (the alpha-gal epitope). Since that time, an extensive literature has developed on discoveries related to the alpha-gal epitope and the anti-Gal antibody, including the barrier they form in xenotransplantation and their reciprocity in mammalian evolution. This review covers these topics and new avenues of clinical importance related to this unique antigen/antibody system (alpha-gal epitope/anti-Gal) in improving the efficacy of viral vaccines and in immunotherapy against cancer.
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33
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Stone KR, Walgenbach AW, Turek TJ, Somers DL, Wicomb W, Galili U. Anterior cruciate ligament reconstruction with a porcine xenograft: a serologic, histologic, and biomechanical study in primates. Arthroscopy 2007; 23:411-9. [PMID: 17418335 DOI: 10.1016/j.arthro.2006.12.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 12/15/2006] [Accepted: 12/28/2006] [Indexed: 02/02/2023]
Abstract
PURPOSE This study proposes treatment methods to provide a mechanically competent, immunocompatible, and sterile porcine graft for human knee ligament reconstruction. METHODS The anterior cruciate ligament (ACL) was reconstructed by using treated porcine patellar tendon grafts or controls of untreated porcine grafts or allografts in 20 rhesus monkeys. Animals were stratified into 2-, 6-, and 12-month postreconstruction cohorts. Serologic and histologic assessments were performed to evaluate host immunological and cellular response. Healing and functional integrity of the ACL reconstructions were assessed by tensile biomechanical testing. RESULTS Untreated porcine grafts were acutely resorbed and rejected, whereas treated porcine grafts and allografts were incorporated by the host as functional grafts. Temporal histologic assessment of treated porcine grafts and rhesus grafts revealed gradual host cellular infiltration and graft collagen remodeling through a similar mechanism of ligamentization. Biomechanical evaluations support graft functional integration with no difference between allograft and treated graft reconstructions. CONCLUSION Rhesus allograft and treated porcine grafts presented with similar healing profiles in a long-term evaluation of ACL reconstruction. CLINICAL RELEVANCE Immunochemical modification and sterilization of porcine patellar tendon grafts may improve initial biocompatibility and long-term functionality of xenografts in musculoskeletal applications.
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34
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Galili U. Xenotransplantation and ABO incompatible transplantation: The similarities they share. Transfus Apher Sci 2006; 35:45-58. [PMID: 16905361 DOI: 10.1016/j.transci.2006.05.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 05/19/2006] [Indexed: 11/15/2022]
Abstract
Transplantation of kidney allografts across the ABO barrier has been feasible with the development of technologies for removal of anti-blood group antibodies from the circulation of the recipent. The recipients of ABO incompatible grafts display tolerance, accommodation or rejection of the graft. Understanding the factors that determine the outcome of the immune response against incompatible blood group antigens has required the study of an appropriate experimental animal model. The model used is that of knockout (KO) mice for the alpha1,3galactosyltransferase gene, lacking the alpha-gal epitopes and transplanted with wild type mouse heart expressing the alpha-gal epitope. The alpha-gal epitope (Galalpha1-3Galbeta1-(3)4GlcNAc-R) is one of the most abundant carbohydrate epitopes on cells of non-primate mammals and New World monkeys, where it is synthesized by the glycosylation enzyme alpha1,3galactosyltransferase. In humans, apes and Old World monkeys, this epitope is absent due to an evolutionary event that led to the inactivation of the alpha1,3galactosyltransferase gene in ancestral Old World primates. Instead, humans, apes and Old World monkeys produce a natural antibody, the anti-Gal antibody, that is the most abundant natural antibody in humans (approximately 1% of circulating immunoglobulins) and which specifically interacts with alpha-gal epitopes. The interaction between anti-Gal and alpha-gal epitopes is a major immunologic barrier in xenotransplantation, preventing transplantation of pig organs or tissues (i.e. xenografts) into humans. Anti-Gal antibodies also comprise a large proportion of anti-blood group B activity in A and O individuals. Moreover, in recipients of ABO incompatible grafts, much of the elicited anti-A and anti-B antibodies are in fact anti-Gal antibodies capable of binding also to the incompatible blood group antigens. Since the alpha-gal epitope is very similar in its structure to blood groups A and B, understanding anti-Gal response to alpha-gal epitopes is likely to provide information on the immune response to ABO incompatible antigens. Studies on the immune response to alpha-gal epitopes in KO mice have indicated that this epitope can not activate T cells. Anti-Gal B cells engaging alpha-gal epitopes on transplated wild type mouse heart can be activated to produce their antibodies only if they receive help from T cells that are activated by allogeneic or xenogeneic peptides. If T cell help is not available for several days the B cells are induced to differentiate into cells capable of producing accommodating antibodies. Accommodating anti-Gal antibodies bind to the incompatible carbohydrate antigen but do not induce rejection. Prolonged exposure of anti-Gal B cells to the incompatible alpha-gal epitope on the wild type mouse heart graft induces tolerance due to the deletion of these B cells. These studies imply that similar variation in the availability of T cell help in recipients of ABO incompatible grafts result in rejection, accommodation or tolerance, to the blood group antigen. The studies on immune response to incompatible alpha-gal epitopes have further indicated that tolerance to incompatible blood group antigens can be achieved by gene therapy with autologous bone marrow cells or autologous lymphocytes engineered to express the incompatible blood group antigen. Studies in the mouse model suggest that administration into the patient such autologous cells engineered to express the incompatible transplantation carbohydrate antigen induces deletion of anti-blood group B cells and induction of tolerance, provided that the anti-blood group antibodies are removed. Such tolerance is perpetuated indefinitely by the subsequent transplantation of the organ expressing the incompatible blood group antigen.
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Affiliation(s)
- Uri Galili
- Department of Medicine, University of Massachusetts Medical School, LRB, Worcester, MA 01605, USA.
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Kim YG, Kim SY, Hur YM, Joo HS, Chung J, Lee DS, Royle L, Rudd PM, Dwek RA, Harvey DJ, Kim BG. The identification and characterization of xenoantigenic nonhuman carbohydrate sequences in membrane proteins from porcine kidney. Proteomics 2006; 6:1133-42. [PMID: 16470663 DOI: 10.1002/pmic.200500275] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The immunogenic nonhuman carbohydrate sequences in membrane proteins from porcine kidney were identified and characterized using MALDI-TOF MS and ESI-QTOF-MS. The MALDI profile, investigated by incubation with exoglycosidases, showed a series of about 40 carbohydrates that were identified as high mannose glycans (Man(3-9)GlcNAc2) and complex bi-, tri-, and tetra-antennary glycans with and without core fucose. The antennae of many of the complex glycans were terminated with alpha-galactose residues, with the numbers of these residues ranging from one up to the number of antennae. Negative ion ESI-MS/MS spectra confirmed the location of the alpha-galactose residues on the ends of the antennae. This total glycan profile of the membrane proteins from porcine kidney will thus provide important information for the study of molecular interactions between antigenic carbohydrates and proteins in xenotransplantation.
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Affiliation(s)
- Yun-Gon Kim
- Interdisciplinary Program of Biochemical Engineering and Biotechnology, Seoul National University, Seoul, Korea
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Galili U. The alpha-gal epitope and the anti-Gal antibody in xenotransplantation and in cancer immunotherapy. Immunol Cell Biol 2005; 83:674-86. [PMID: 16266320 DOI: 10.1111/j.1440-1711.2005.01366.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: 01/03/2023]
Abstract
The alpha-gal epitope (Galalpha1-3Galbeta1-(3)4GlcNAc-R) is abundantly synthesized on glycolipids and glycoproteins of non-primate mammals and New World monkeys by the glycosylation enzyme alpha1,3galactosyltransferase (alpha1,3GT). In humans, apes and Old World monkeys, this epitope is absent because the alpha1,3GT gene was inactivated in ancestral Old World primates. Instead, humans, apes and Old World monkeys produce the anti-Gal antibody, which specifically interacts with alpha-gal epitopes and which constitutes approximately 1% of circulating immunoglobulins. Anti-Gal has functioned as an immunological barrier, preventing the transplantation of pig organs into humans, because anti-Gal binds to the alpha-gal epitopes expressed on pig cells. The recent generation of alpha1,3GT knockout pigs that lack alpha-gal epitopes has resulted in the elimination of this immunological barrier. Anti-Gal can be exploited for clinical use in cancer immunotherapy by targeting autologous tumour vaccines to APC, thereby increasing their immunogenicity. Autologous intact tumour cells from haematological malignancies, or autologous tumour cell membranes from solid tumours are processed to express alpha-gal epitopes by incubation with neuraminidase, recombinant alpha1,3GT and with uridine diphosphate galactose. Subsequent immunization with such autologous tumour vaccines results in in vivo opsonization by anti-Gal IgG binding to these alpha-gal epitopes. The interaction of the Fc portion of the vaccine-bound anti-Gal with Fcgamma receptors of APC induces effective uptake of the vaccinating tumour cell membranes by the APC, followed by effective transport of the vaccinating tumour membranes to the regional lymph nodes, and processing and presentation of the tumour-associated antigen (TAA) peptides. Activation of tumour-specific T cells within the lymph nodes by autologous TAA peptides may elicit an immune response that in some patients will be potent enough to eradicate the residual tumour cells that remain after completion of standard therapy. A similar expression of alpha-gal epitopes can be achieved by transduction of tumour cells with an adenovirus vector (or other vectors) containing the alpha1,3GT gene, thus enabling anti-Gal-mediated targeting of the vaccinating transduced cells to APC. Intratumoral delivery of the alpha1,3GT gene by various vectors results in the expression of alpha-gal epitopes. Such expression of the xenograft carbohydrate phenotype is likely to induce anti-Gal-mediated destruction of the tumour lesion, similar to rejection of xenografts by this antibody. Opsonization of the destroyed tumour cell membranes by anti-Gal IgG further targets them to APC, thus converting the tumour lesion, treated by the alpha1,3GT gene, into an in situ autologous tumour vaccine.
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Affiliation(s)
- Uri Galili
- Division of Hematology/Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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Abstract
The success of allotransplantation has led to an increasing shortage of human organs from deceased donors. This crisis could be resolved by the use of organs from an anatomically suitable animal, such as the pig. The pig and human have, however, been evolving differently for approximately 80 million years, and numerous immunological and physiological barriers have developed that need to be overcome. Differences in carbohydrate epitopes on pig and human cells have been found to play a major role in some of the immunological barriers that have been identified to date. The rejection caused by the presence of galactose-alpha1,3-galactose (Gal) on the pig vascular endothelium and of natural anti-Gal antibodies in humans has recently been prevented by the breeding of pigs that do not express Gal, achieved by knocking out the gene for the enzyme alpha1,3-galactosyltransferase, which was made possible by the introduction of nuclear transfer/embryo transfer techniques. N-glycolylneuraminic acid (the so-called Hanganutziu-Deicher antigen) has been identified as another carbohydrate antigen present in pigs that may need to be deleted if xenotransplantation is to be successful, although some doubt remains regarding its importance. There remain other antipig antibodies against hitherto unidentified antigenic targets that may well be involved in graft destruction; their possible carbohydrate target epitopes are discussed.
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Affiliation(s)
- Mohamed Ezzelarab
- Thomas E Starzl Transplantation Institute, University of Pittsburgh MedicalCenter, Pittsburgh, Pennsylvania 15261, USA
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Abstract
Organ transplantation is considered the most effective treatment for end-stage organ failure; currently it is limited by a severe worldwide shortage of human donor organs. This has led to investigation of the potential use of animals as organ donors. For a number of reasons, the pig represents the most likely organ donor candidate. Transplantation of a vascularised porcine organ into a human or non-human primate results in an immediate and dramatic rejection process, known as hyperacute rejection, which is mediated by the binding of pre-existing antibody to the porcine graft and the subsequent activation of host complement. Strategies aimed at preventing this initial rejection have been largely successful in experimental models. This has allowed attention to turn towards an understanding of the immunological barriers comprising the next phase of xenograft rejection, termed acute vascular rejection. This delayed rejection process appears to be a humoral event, and it is likely that the control of antibody synthesis will play a pivotal role in overcoming the current barrier to successful xenotransplantation.
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Affiliation(s)
- L E Diamond
- Nextran, Inc., 303B College Road East, Princeton, NJ, USA.
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Gollackner B, Goh SK, Qawi I, Buhler L, Knosalla C, Daniel S, Kaczmarek E, Awwad M, Cooper DKC, Robson SC. Acute vascular rejection of xenografts: roles of natural and elicited xenoreactive antibodies in activation of vascular endothelial cells and induction of procoagulant activity. Transplantation 2004; 77:1735-41. [PMID: 15201675 DOI: 10.1097/01.tp.0000131167.21930.b8] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Hyperacute rejection of vascularized discordant xenografts can now be effectively managed. However, acute vascular rejection (AVR) then ensues, resulting in graft destruction, coagulopathy, or both within weeks. The aim of this study was to determine associations between humoral responses to the xenograft and the induction of AVR, coagulopathy, or both. METHODS In vitro, heat-inactivated, naive or sensitized baboon sera containing xenoreactive natural or elicited antibodies were used to activate porcine aortic endothelial cells (PAEC) in vitro. Tissue factor expression on PAEC was determined as an index of heightened procoagulant activity. In vivo, porcine renal xenografts were transplanted into immunosuppressed baboons, and at the time of rejection or the development of a consumptive coagulopathy, biopsy specimens were obtained for studies of xenoreactive antibody binding and tissue factor expression. RESULTS In vitro, incubation of PAEC with naive baboon sera containing natural anti-Galalpha1,3Gal (Gal) antibodies resulted in minimal tissue factor induction; the addition of complement boosted procoagulant responses. Elicited xenoreactive antibodies, and to non-Gal epitopes alone, induced high amounts of procoagulant activity on PAEC; the addition of complement resulted in overt cytotoxicity. In vivo, AVR was associated with xenoreactive antibody deposition in the graft. When vascular endothelial binding of xenoreactive antibody was combined with the expression of tissue factor, consumptive coagulopathy developed irrespective of histopathologic features of AVR. CONCLUSIONS Our in vitro results indicate that elicited antibodies, potentially to non-Gal epitopes, induce endothelial cell activation and tissue factor expression; in vivo, a consumptive coagulopathy occurred when there was xenoreactive antibody deposition and increase of tissue factor.
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Affiliation(s)
- Bernd Gollackner
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02215, USA
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Kuwaki K, Knosalla C, Dor FJMF, Gollackner B, Tseng YL, Houser S, Mueller N, Prabharasuth D, Alt A, Moran K, Cheng J, Behdad A, Sachs DH, Fishman JA, Schuurman HJ, Awwad M, Cooper DKC. Suppression of natural and elicited antibodies in pig-to-baboon heart transplantation using a human anti-human CD154 mAb-based regimen. Am J Transplant 2004; 4:363-72. [PMID: 14961988 DOI: 10.1111/j.1600-6143.2004.00353.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Natural and elicited antipig antibodies (Abs) lead to acute humoral xenograft rejection (AHXR). Ten baboons underwent heterotopic heart transplantation (Tx) from human decay-accelerating factor (hDAF) pigs. Depletion of anti-Galalpha1, 3Gal (Gal) Abs was achieved by the infusion of a Gal glycoconjugate from day-1. Immunosuppression included induction of antithymocyte globulin, thymic irradiation, and cobra venom factor, and maintenance with a human antihuman CD154 mAb, mycophenolate mofetil, and methylprednisolone; heparin and prophylactic ganciclovir were also administered. Pig heart survival ranged from 4 to 139 (mean 37, median 27) days, with three functioning for >50 days. Graft failure (n = 8) was from classical AHXR [4], thrombotic microangiopathy [3], or intragraft thrombosis [1], with death (n = 2) from pneumonia [1], or possible drug toxicity (with features of thrombotic microangiopathy) [1]. Anti-Gal Abs (in microg/mL) were depleted by Gal glycoconjugate before graft implantation from means of 41.3 to 6.3 (IgM) and 12.4-4.6 (IgG), respectively, and at graft excision were 6.3 and 1.7 microg/mL, respectively. No elicited Abs developed, and no cellular infiltration was seen. The treatment regimen was effective in maintaining low anti-Gal Ab levels and in delaying or preventing AHXR. The combination of costimulatory blockade and heparin with Tx of a Gal-negative pig organ may prolong graft survival further.
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Affiliation(s)
- Kenji Kuwaki
- Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA
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Johnstone JE, MacLaren LA, Doucet J, McAlister VC. In vitro studies regarding the feasibility of bovine erythrocyte xenotransfusion. Xenotransplantation 2004; 11:11-7. [PMID: 14962288 DOI: 10.1111/j.1399-3089.2004.00070.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Pigs are considered the most likely source of organs and tissues should the barriers to xenotransplantation be overcome. The use of animal blood for transfusion, xenotransfusion, would have advantages over blood from random human donors with respect to supply and infection control. Large animals such as cows would be more suitable than pigs for blood donation because of easier venous access and large volume phlebotomy. Blood from 12 Holstein cows was typed and then tested for hemagglutination assay (HA), complement mediated lysis (CML), human IgM and IgG antibody binding, anti-human globulin augmented clinical cross-match and osmotic fragility with normal human serum. Results were compared with porcine erythrocytes (pRBC) and with human type O controls (hRBC). The frequency of ultra-low xenoantigen expressors was tested in a larger herd of various breeds using HA and CML. Median HA and CML titers were one of six (no HA-one of 64) and one of 26 (no CML-one of 64), respectively for bovine erythrocytes (bRBC). Hemagglutination titer was significantly higher for pRBC at one of 170 (one of four-one of 1024). HA and CML were lowest with bovine blood group J. Repeated HA and CML were negative with bRBC from one cow that also tested negative by anti-human globulin augmented cross-match with seven of nine random human sera representing the different blood groups. However, flow cytometry showed that bRBC from all cows bound human IgM and IgG. IgM mean channel fluorescence (MCF) was positively correlated with HA titer. The mean corpuscular fragility of pRBC, bRBC, and hRBC was 0.56, 0.48 and 0.41%, respectively. The frequency of HA-negative and CML-negative cows were 20 and 35%, respectively in herds of 49 animals. Bovine RBC elicit variable in vitro responses from human serum but these are uniformly much less than those seen with pRBC. Bovine RBC is more robust than pRBC. These characteristics including the potential ease and volume of blood collection make the cow a more suitable blood donor than the pig.
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Affiliation(s)
- James E Johnstone
- Department of Plant and Animal Sciences, Nova Scotia Agricultural College, Truro, Canada
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Luo Y, Levy G, Garcia BM, Yang H, Phillips J, Noble L, Chakrabarti S, Grant D, Zhong R. Ex vivo and extracorporeal perfusion with hDAF pig kidneys. Xenotransplantation 2003; 10:410-21. [PMID: 12950984 DOI: 10.1034/j.1399-3089.2003.02050.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present study was undertaken to determine whether human decay accelerating factor (hDAF) transgene would prevent hyperacute rejection (HAR) while perfused with human blood or extracorporeally in baboons. Four hDAF pig kidneys and three non-hDAF pig kidneys were perfused ex vivo with fresh human blood for 6 h. Additionally four hDAF pig kidneys and four non-hDAF pig kidneys were extracorporeally perfused in baboons and pigs, respectively, for 3 h. In ex vivo perfusion, the color of hDAF pig kidneys remained pink at the end of 6-h perfusion and they had normal histology, while non-hDAF kidneys developed HAR. HDAF pig kidneys had superior function over non-transgenic pig kidneys. Urine output was 17.31 +/- 3.70 ml/h for hDAF pig kidneys, and only 5.81 +/- 0.26 ml/h for non-hDAF kidneys (P < 0.05). Creatinine clearance was 1.16 +/- 1.24 ml/min for hDAF kidneys and 0.22 +/- 0.15 ml/min for non-hDAF kidneys (P < 0.05). Other functional data including potassium, urine specific density, and osmolality were normal in the hDAF kidneys, while in non-hDAF kidneys, serum potassium was elevated to over 9 mmol/l by the end of perfusion (P < 0.01). Non-hDAF kidneys also lost more sodium through urine than hDAF kidneys (173.67 +/- 14.05 mmol/l vs. 109 +/- 31 mmol/l, P < 0.05). In the extracorporeal perfusion, all the baboons tolerated the procedure well with normal hemodynamic and hemotologic profiles. These baboons were well until killed 42 to 56 days after perfusion, although their antiporcine antibodies were greatly elevated. We conclude that hDAF transgene protects against HAR, allowing the pig kidney to function normally while perfused with human blood, and that extracorporeal perfusion using hDAF pig kidneys is a safe procedure in baboons.
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Affiliation(s)
- Yigang Luo
- Department of Surgery, The University of Western Ontario, London, Ontario, Canada
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Buhler L, Xu Y, Li W, Zhu A, Cooper DKC. An investigation of the specificity of induced anti-pig antibodies in baboons. Xenotransplantation 2003; 10:88-93. [PMID: 12535230 DOI: 10.1034/j.1399-3089.2003.01122.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIM To provide information on the specificity of induced anti-pig antibodies (Abs) in baboons after exposure and sensitization to pig antigens. MATERIALS AND METHODS Baboons (n=7) received either porcine mobilized peripheral blood progenitor cells (n=3), kidney (n=3) or heart (n=1) transplants. After rejection of these cells or organs, pre- and post-rejection sera were analyzed by enzyme-linked immunosorbent assay (ELISA) and flow cytometry to detect and measure anti-Galactosealpha1,3Galactose (Gal) and anti-non-Gal Abs. To study the anti-non-Gal carbohydrate response, the sera were incubated with pig red blood cells pretreated with alpha-galactosidase (to remove Gal) and three other exoglycosidases to remove other potential oligosaccharide epitopes, and studied by flow cytometry. To study the anti-swine leukocyte antigen (SLA) response, non-Gal Abs from two baboons sensitized with kidneys from inbred miniature swine of dd or aa haplotype, respectively, were adsorbed on cells of aa, cc, or dd haplotypes, and binding to aa, cc or dd cells was measured by flow cytometry. Cytotoxicity of anti-non-Gal Abs was tested in vitro by a complement-mediated cytotoxicity assay, using pig cells as targets. RESULTS In pre-transplant and pre-rejection sera, anti-Gal Abs were detected, but anti-non-Gal Abs were either absent or at minimal levels. After exposure to pig antigens, baboons developed induced anti-Gal and anti-non-Gal Abs. No anti-non-Gal Abs directed to the tested carbohydrate epitopes could be detected. Anti-non-Gal Abs showed minor evidence of specific SLA haplotype reactivity, suggesting that the major Ab response was to pan-pig determinants. Anti-non-Gal Abs showed a low level of complement-mediated lysis of pig cells in vitro. CONCLUSIONS In this limited study, no Ab response to non-Gal carbohydrates was observed, and anti-SLA specificity was minor, indicating that most induced anti-non-Gal Ab was directed against non-specific pig proteins, including SLA-epitopes.
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Affiliation(s)
- L Buhler
- The Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
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Galili U, Ishida H, Tanabe K, Toma H. Anti-gal A/B, a novel anti-blood group antibody identified in recipients of abo-incompatible kidney allografts. Transplantation 2002; 74:1574-80. [PMID: 12490791 DOI: 10.1097/00007890-200212150-00015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The most prevalent anticarbohydrate antibodies in human serum are anti-Gal interacting specifically with the alpha-gal epitope (Galalpha1-3Galbeta1-4GlcNAc-R) and anti-blood group antibodies interacting with blood group A and B antigens. The alpha-gal epitope, although absent in humans, comprises part of the core of carbohydrate chain in A and B antigens. Therefore, it was of interest to determine whether immunoglobulin (Ig) G antibodies, elicited in patients rejecting ABO-incompatible kidney allografts, can interact with the alpha-gal epitope. METHODS Anti-A and anti-B antibodies were determined by enzyme-linked immunosorbent assay (ELISA) with blood group A or B human red cell membranes, as solid phase antigens. Anti-Gal was determined by ELISA with alpha-gal-bovine serum albumin as solid-phase antigen. Specific removal of anti-Gal was performed by adsorption on fixed rabbit red cells. RESULTS Blood group O patients who underwent transplantation with either A or B kidney produced an antibody that bound to all three carbohydrate antigens. This multispecific antibody, designated anti-Gal A/B, is specific to the core alpha-gal epitope within A and B antigens. Recipients of allograft expressing incompatible blood group B also produce anti-Gal B antibody, which binds to the core alpha-gal epitope only in the B antigen. Anti-Gal A/B and anti-Gal B constitute most of the elicited anti-blood group antibody response. Allograft recipients also produced pure anti-A, or pure anti-B, which require the complete blood group structure for binding. CONCLUSIONS The findings in this study imply that much of the immune response elicited by incompatible A or B antigens on kidney allografts results in activation of anti-Gal B-cell clones producing antibodies to the core alpha-gal epitope in these blood group antigens. Only less than 25% of the elicited antibodies interact with the complete A or B antigens (i.e., pure anti-A or pure anti-B). These findings suggest that prevention of the anti-Gal response may decrease the immune rejection of ABO-incompatible allografts.
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Affiliation(s)
- Uri Galili
- Department of Cardiovascular-Thoracic Surgery, Rush University, Chicago, IL 60612, USA.
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Tanemura M, Chong AS, DiSesa VJ, Galili U. Direct killing of xenograft cells by CD8+ T cells of discordant xenograft recipients. Transplantation 2002; 74:1587-95. [PMID: 12490793 DOI: 10.1097/00007890-200212150-00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Long-term pig xenografts in monkeys demonstrated the infiltration of CD8 T cells into pig cartilage xenografts, transplanted into monkeys. The objective of the present study was to determine in an experimental animal model whether CD8 T cells in pig xenograft recipients exert any direct cytotoxic effect on pig cells. METHODS The killing of xenograft cells by CD8 T cells, obtained from xenograft recipients, was studied in alpha1,3galactosyltransferase knockout mice that were repeatedly injected intraperitoneally with pig kidney membranes. The pig kidney cell line PK15, which shares many antigens with pig kidney membranes, served as a model for xenograft target cells in cytotoxicity assays. Cell lines from other species were also studied as target cells. RESULTS Lymphocytes obtained freshly from spleens of mice immunized with pig kidney membranes failed to display significant cytotoxic activity against pig cells. However, incubation of these lymphocytes with irradiated PK15 cells and addition of recombinant interleukin (IL)-2 (100 U/mL), on the third day of incubation, resulted in extensive proliferation and expansion of CD8 cytotoxic T lymphocytes (CTL). These CTL, obtained after 12 days of incubation, killed nonspecifically pig, human, and mouse normal and malignant cells. These CTL were not generated in cultures in the absence of stimulatory pig cells or in the absence of IL-2. These CTL could not be generated in cultures of lymphocytes from naive mice that were incubated with PK15 cells and IL-2. CONCLUSIONS The data obtained imply that CD8 T cells from xenograft recipients can be stimulated in vitro by xenoantigens and IL-2 to differentiate into highly reactive nonspecific CTL that are capable of killing a large variety of xenogeneic and syngeneic cells. Similar in vivo microenvironmental conditions within the xenograft may induce the local differentiation of infiltrating CD8 T cells into CTL that can destroy nonspecifically adjacent xenograft cells. Such cells may not be active outside the xenograft because of the absence of IL-2 in sufficiently high concentrations.
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Affiliation(s)
- Masahiro Tanemura
- Department of Cardiovascular-Thoracic Surgery, Rush University, Chicago, IL 60612, USA
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Diamond LE, Byrne GW, Schwarz A, Davis TA, Adams DH, Logan JS. Analysis of the control of the anti-gal immune response in a non-human primate by galactose alpha1-3 galactose trisaccharide-polyethylene glycol conjugate. Transplantation 2002; 73:1780-7. [PMID: 12085001 DOI: 10.1097/00007890-200206150-00014] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The current limitation to the clinical application of xenotransplantation using pig organs is a rejection process that has been termed delayed xenograft rejection or acute vascular rejection. It is thought that acute vascular rejection may be mediated at least in part by both the continued synthesis, of preexisting, and the induction, posttransplantation, of antibodies against the carbohydrate moiety galalpha1-3gal that is present on glycoproteins and glycolipids of the pig endothelium. The synthesis of these antibodies has proven difficult to control with currently available immunosuppressive agents. METHODS We have synthesized galalpha1-3gal conjugated polyethylene glycol polymers that can bind to anti-galalpha1-3gal antibodies and tested their activity in non-human primates. RESULTS These conjugates when administered to non-human primates can substantially reduce the levels of preexisting and control the induction of anti-galalpha1-3gal antibodies. The level of circulating antibody-secreting cells that make anti-galalpha1-3gal antibodies is also reduced. CONCLUSION These alpha-gal polyethylene glycol conjugates may have the potential to control the anti-gal antibody response in a pig to primate organ transplant setting and may be a useful therapeutic agent in prolonging graft survival.
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Affiliation(s)
- Lisa E Diamond
- Nextran Inc., 303B College Road East, Princeton, NJ 08540, USA
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Abstract
Gene transfer and gene therapy represent a relatively new field that has grown and expanded enormously in the last 5-10 years. The application of gene transfer and gene medicines to transplantation is currently in its infancy. Consideration for gene medicines in transplantation requires delivery of vectors, either to the graft or to the immune system. Delivery of vectors to the graft provides a choice of potential immunologic targets including: costimulatory signals; inhibitory cytokines; adhesion molecules; and molecules relating to apoptosis. In addition, non-immunologic targets, that increase graft protective mechanisms by reducing ischemic and immunologic damage, represent significant targets for gene transfer. Delivery of vectors to the immune system includes potential targets to modify the immune system, and results in tolerance. Other considerations for gene therapy include the development of additional technologies, such as gene conversion or transgenesis coupled with xenotransplantation, which may provide genetically modified organs. Another important aspect of gene transfer relates to regulation of the transgene expression. A variety of issues concerning innate immunity, adaptive immunity, response to vector components, response to transgene products, and entry of vectors into the antigen presentation and processing pathway require further investigation and refinement of approaches. Lastly, regulatable promoters and the understanding of their interaction with individual cells, tissues and organs, and their interaction with innate and adaptive immunity, are of paramount importance to improving the efficacy and utility of gene transfer. There is no doubt that there is much exciting basic and translational science to be accomplished in the next decade in order to solve these potential barriers and advance gene medicines into the clinical realm in transplantation.
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Affiliation(s)
- D Chen
- Carl C. Icahn Institute for Gene Therapy and Molecular Medicine and the Recanati/Miller Transplantation Institute, Mount Sinai School of Medicine, New York, NY 10029-6574, USA
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Byrne GW, Schwarz A, Fesi JR, Birch P, Nepomich A, Bakaj I, Velardo MA, Jiang C, Manzi A, Dintzis H, Diamond LE, Logan JS. Evaluation of different alpha-Galactosyl glycoconjugates for use in xenotransplantation. Bioconjug Chem 2002; 13:571-81. [PMID: 12009948 DOI: 10.1021/bc015565e] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Porcine organs are rapidly rejected after transplantation into primate recipients due to the presence of preexisting immunoglobulins that bind to terminal galactose alpha1,3 galactose residues (alpha-galactosyl) present on porcine glycoproteins and glycolipids. Currently available immunosuppressive reagents have been largely ineffective at controlling the synthesis of these anti-Gal antibodies. Nonantigenic hapten polymers have been shown to be effective materials for blocking humoral immune responses in various model systems. We have developed a series of alpha-galactosyl glycoconjugate polymers and tested their ability to block anti-Gal antibody binding in vitro and in vivo. A galactose alpha1,3 galactose beta 1,4 GlcNAc trisaccharide free acid (TRFA) with a hexanoic acid spacer, containing five methylene groups and a carboxylic acid, was produced and coupled to a variety of polymeric backbones including dextran, branched poly(ethylene glycol) (PEG), and poly-L-lysine. The ability of monomeric TRFA and the alpha-galactosyl conjugates to block anti-Gal IgG and IgM binding was determined using a competition ELISA assay on defined HSA-Gal glycoconjugates and porcine microvascular endothelial cell substrates. We show that branched PEG carriers, with a TRFA sugar attached to each branch, exhibit enhanced antibody blocking ability compared to TRFA, but at higher target antigen densities these simple PEG conjugates are no more effective then an equivalent amount of TRFA in blocking anti-Gal IgM antibody interactions. In contrast, polymers of the branched PEG conjugates and linear conjugates made using dextran and poly-L-lysine were 2000 to 70000-fold more effective inhibitors of anti-Gal antibodies. In a study using nonhuman primates, a single dose infusion of polymeric PEG or dextran glycoconjugates dramatically reduced the level of circulating anti-Gal antibodies in cynomologus monkeys for at least 72 h. Glycoconjugates similar to these might be useful both to block anti-Gal interactions in vivo and to specifically control the induced anti-Gal immune response.
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Affiliation(s)
- Guerard W Byrne
- Nextran Inc., 303B College Road, Princeton, New Jersey, USA.
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Richards AC, Davies HFS, McLaughlin ML, Copeman LS, Holmes BJ, Dos Santos Cruz G, Bycroft S, Chavez G, White DJG, Schuurman HJ, Cozzi E. Serum anti-pig antibodies as potential indicators of acute humoral xenograft rejection in pig-to-cynomolgus monkey kidney transplantation. Transplantation 2002; 73:881-9. [PMID: 11923687 DOI: 10.1097/00007890-200203270-00009] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Hyperacute rejection of solid organ pig xenografts in nonhuman primates has been overcome by using donors transgenic for human complement regulatory proteins, but grafts are still susceptible to humoral (antibody-mediated) rejection. We investigated whether circulating xenoreactive antibodies are a useful indicator of this xenograft rejection. METHODS Five assays were employed in a retrospective analysis on 20 selected cynomolgus monkey recipients of renal xenografts transgenic for human decay-accelerating factor, with survival between 4 and 60 days. The assays included hemolytic and hemagglutination assays and the measurement of immunoglobulin (Ig)G and IgM binding to porcine endothelial cells and leukocytes, and to the Gal alpha 1-3Gal trisaccharide (Gal) antigen. To assess non-Gal-directed antibodies, sera were absorbed with a Gal-coated resin. A predictive value was defined as an increase in antibody levels before a decline in graft failure (>20% increase in creatinine levels) and humoral rejection in graft pathology. RESULTS Data on hemolytic anti-pig antibody correlated with those on IgM antibody to endothelial cells, leukocytes, and Gal. In absorbed sera IgM and IgG antibody to endothelial cells and leukocytes correlated with each other, indicative for an elicited antibody response to non-Gal antigens. Sixteen animals showed humoral rejection, and in all but two animals one or more assays was considered of predictive value. On the other hand, increased antibody levels were noted in two animals without signs of rejection in graft pathology and in two cases with cellular xenograft rejection. CONCLUSIONS It is recommended to use multiple assays (preferably hemolytic, anti-Gal, and anti-endothelial cell) to be able to fully monitor the peripheral antibody responses in pig-to-primate xenograft recipients.
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Bühler L, Yamada K, Kitamura H, Alwayn IP, Basker M, Appel JZ, Colvin RB, White-Scharf ME, Sachs DH, Robson SC, Awwad M, Cooper DK. Pig kidney transplantation in baboons: anti-Gal(alpha)1-3Gal IgM alone is associated with acute humoral xenograft rejection and disseminated intravascular coagulation. Transplantation 2001; 72:1743-52. [PMID: 11740383 DOI: 10.1097/00007890-200112150-00007] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Kidneys harvested from miniature swine or pigs transgenic for human decay-accelerating factor (hDAF) were transplanted into baboons receiving an anti-CD154 monoclonal antibody (mAb) and either a whole body irradiation (WBI)- or cyclophosphamide (CPP)-based immunosuppressive regimen. METHODS Group 1 baboons (n=3) underwent induction therapy with WBI and thymic irradiation, pretransplantation antithymocyte globulin, and immunoadsorption of anti-Gal(alpha)1-3Gal (Gal) antibody (Ab). After transplantation of a miniature swine kidney, maintenance therapy comprised cobra venom factor, mycophenolate mofetil, and an anti-CD154 mAb (for 14-28 days). In group 2 (n=2), WBI was replaced by CPP in the induction protocol. Group 3 (n=3) animals received the group 2 regimen, but underwent transplantation with hDAF pig kidneys. RESULTS Group 1 and 2 animals developed features of disseminated intravascular coagulation (DIC), with reductions of fibrinogen and platelets and increases of prothrombin time, partial thromboplastin time, and fibrin split products. Graft survival was for 6-13 days. Histology showed mild acute humoral xenograft rejection (AHXR) of the kidneys, but severe rejection of the ureters. Group 3 animals developed features of DIC in two of three cases during the fourth week, with AHXR in the third case. Graft survival was for 28 (n=1) or 29 (n=2) days. Histology of day 15 biopsy specimens showed minimal focal mononuclear cellular infiltrates, with predominantly CD3+ cells. By days 28 and 29, kidneys showed mild-to-moderate features of AHXR. In all groups, the humoral response was manifest by reappearance of anti-Gal IgM below baseline level, with no or low return of anti-Gal IgG. All excised kidneys showed IgM deposition, but no complement and no or minimal IgG deposition. No baboon showed a rebound of anti-Gal Ab immediately after excision of the graft, and anti-Gal Ab increased over pretransplantation levels only when anti-CD154 mAb was discontinued. CONCLUSIONS DIC was observed with WBI- or CPP-based therapy, and after miniature swine or hDAF kidney transplantation. AHXR+/-DIC was observed in all recipients even in the absence of complement and no or low levels of anti-Gal IgG, but was significantly delayed in the hDAF recipients. These results confirm our earlier observation that CD154 blockade prevents T cell-dependent sensitization in baboons to pig antigens, but that baseline natural anti-Gal Ab production is not inhibited. We suggest that IgM deposition, even in the absence of IgG and complement, leads to endothelial cell activation with the development of DIC, even when there are only minimal histologic changes of AHXR.
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Affiliation(s)
- L Bühler
- Transplantation Biology Research Center, Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston 02129, USA
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