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Ladowski JM, Martens GR, Reyes LM, Wang ZY, Eckhoff DE, Hauptfeld-Dolejsek V, Tector M, Tector AJ. Examining the Biosynthesis and Xenoantigenicity of Class II Swine Leukocyte Antigen Proteins. THE JOURNAL OF IMMUNOLOGY 2018. [PMID: 29540579 DOI: 10.4049/jimmunol.1800022] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Genetically engineered pig organs could provide transplants to all patients with end-stage organ failure, but Ab-mediated rejection remains an issue. This study examines the class II swine leukocyte Ag (SLA) as a target of epitope-restricted Ab binding. Transfection of individual α- and β-chains into human embryonic kidney cells resulted in both traditional and hybrid class II SLA molecules. Sera from individuals on the solid organ transplant waiting list were tested for Ab binding and cytotoxicity to this panel of class II SLA single-Ag cells. A series of elution studies from an SLA-DQ cell line were performed. Our results indicate that human sera contain Abs specific for and cytotoxic against class II SLA. Our elution studies revealed that sera bind the SLA-DQ molecule in an epitope-restricted pattern. Site-specific mutation of one of these epitopes resulted in statistically decreased Ab binding. Humans possess preformed, specific, and cytotoxic Abs to class II SLA that bind in an epitope-restricted fashion. Site-specific epitope mutagenesis may decrease the Ab binding of highly sensitized individuals to pig cells.
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Affiliation(s)
- Joseph M Ladowski
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | - Gregory R Martens
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | - Luz M Reyes
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | - Zheng-Yu Wang
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | - Devin E Eckhoff
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | | | - Matt Tector
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | - A Joseph Tector
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294; and
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Murthy R, Bajona P, Bhama JK, Cooper DK. Heart Xenotransplantation: Historical Background, Experimental Progress, and Clinical Prospects. Ann Thorac Surg 2016; 101:1605-13. [DOI: 10.1016/j.athoracsur.2015.10.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/14/2015] [Accepted: 10/01/2015] [Indexed: 12/29/2022]
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Cooper DKC. Modifying the sugar icing on the transplantation cake. Glycobiology 2016; 26:571-81. [PMID: 26935763 DOI: 10.1093/glycob/cww028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/25/2016] [Indexed: 12/13/2022] Open
Abstract
As a transplant surgeon, my interest in glycobiology began through my research into ABO-incompatible allotransplantation, and grew when my goal became overcoming the shortage of organs from deceased human donors by the transplantation of pig organs into patients with terminal organ failure (xenotransplantation/cross-species transplantation). The major target for human "natural" (preformed) anti-pig antibodies is galactose-α(1,3)-galactose (the "Gal" epitope), which is expressed on many pig cells, including the vascular endothelium. The binding of human IgM and IgG antibodies to Gal antigens initiates the process of hyperacute rejection, resulting in destruction of the pig graft within minutes or hours. This major barrier has been overcome by the production of pigs in which the gene for the enzyme α(1,3)-galactosyltransferase (GT) has been deleted by genetic engineering, resulting in GT knockout (GTKO) pigs. The two other known carbohydrate antigenic targets on pig cells for human anti-pig antibodies are (i) the product of the cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) gene, i.e., N-glycolylneuraminic acid, and (ii) the product of the β1,4 N-acetylgalactosaminyltransferase gene, i.e., the Sd(a) antigen. Expression of these two has also been deleted in pigs. These genetic manipulations, together with others directed to overcoming primate complement and coagulation activation (the latter of which also relates to glycobiology) have contributed to the prolongation of pig graft survival in nonhuman primate recipients to many months rather than a few minutes. Clinical trials of the transplantation of pig cells are already underway and transplantation of pig organs may be expected within the relatively near future.
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Affiliation(s)
- David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Cooper DKC, Ezzelarab MB, Hara H, Iwase H, Lee W, Wijkstrom M, Bottino R. The pathobiology of pig-to-primate xenotransplantation: a historical review. Xenotransplantation 2016; 23:83-105. [PMID: 26813438 DOI: 10.1111/xen.12219] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/22/2015] [Indexed: 12/16/2022]
Abstract
The immunologic barriers to successful xenotransplantation are related to the presence of natural anti-pig antibodies in humans and non-human primates that bind to antigens expressed on the transplanted pig organ (the most important of which is galactose-α1,3-galactose [Gal]), and activate the complement cascade, which results in rapid destruction of the graft, a process known as hyperacute rejection. High levels of elicited anti-pig IgG may develop if the adaptive immune response is not prevented by adequate immunosuppressive therapy, resulting in activation and injury of the vascular endothelium. The transplantation of organs and cells from pigs that do not express the important Gal antigen (α1,3-galactosyltransferase gene-knockout [GTKO] pigs) and express one or more human complement-regulatory proteins (hCRP, e.g., CD46, CD55), when combined with an effective costimulation blockade-based immunosuppressive regimen, prevents early antibody-mediated and cellular rejection. However, low levels of anti-non-Gal antibody and innate immune cells and/or platelets may initiate the development of a thrombotic microangiopathy in the graft that may be associated with a consumptive coagulopathy in the recipient. This pathogenic process is accentuated by the dysregulation of the coagulation-anticoagulation systems between pigs and primates. The expression in GTKO/hCRP pigs of a human coagulation-regulatory protein, for example, thrombomodulin, is increasingly being associated with prolonged pig graft survival in non-human primates. Initial clinical trials of islet and corneal xenotransplantation are already underway, and trials of pig kidney or heart transplantation are anticipated within the next few years.
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Affiliation(s)
- David K C Cooper
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mohamed B Ezzelarab
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hidetaka Hara
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hayato Iwase
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Whayoung Lee
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Martin Wijkstrom
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rita Bottino
- Institute for Cellular Therapeutics, Allegheny-Singer Research Institute, Pittsburgh, PA, USA
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Cooper DK, Ekser B, Ramsoondar J, Phelps C, Ayares D. The role of genetically engineered pigs in xenotransplantation research. J Pathol 2016; 238:288-99. [PMID: 26365762 PMCID: PMC4689670 DOI: 10.1002/path.4635] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/22/2015] [Accepted: 09/06/2015] [Indexed: 12/12/2022]
Abstract
There is a critical shortage in the number of deceased human organs that become available for the purposes of clinical transplantation. This problem might be resolved by the transplantation of organs from pigs genetically engineered to protect them from the human immune response. The pathobiological barriers to successful pig organ transplantation in primates include activation of the innate and adaptive immune systems, coagulation dysregulation and inflammation. Genetic engineering of the pig as an organ source has increased the survival of the transplanted pig heart, kidney, islet and corneal graft in non-human primates (NHPs) from minutes to months or occasionally years. Genetic engineering may also contribute to any physiological barriers that might be identified, as well as to reducing the risks of transfer of a potentially infectious micro-organism with the organ. There are now an estimated 40 or more genetic alterations that have been carried out in pigs, with some pigs expressing five or six manipulations. With the new technology now available, it will become increasingly common for a pig to express even more genetic manipulations, and these could be tested in the pig-to-NHP models to assess their efficacy and benefit. It is therefore likely that clinical trials of pig kidney, heart and islet transplantation will become feasible in the near future.
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Affiliation(s)
- David K.C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Burcin Ekser
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN
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Cooper DKC, Ekser B, Tector AJ. Immunobiological barriers to xenotransplantation. Int J Surg 2015; 23:211-216. [PMID: 26159291 PMCID: PMC4684773 DOI: 10.1016/j.ijsu.2015.06.068] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 01/26/2023]
Abstract
Binding of natural anti-pig antibodies in humans and nonhuman primates to carbohydrate antigens expressed on the transplanted pig organ, the most important of which is galactose-α1,3-galactose (Gal), activate the complement cascade, which results in destruction of the graft within minutes or hours, known as hyperacute rejection. Even if antibody is removed from the recipient's blood by plasmapheresis, recovery of antibody is associated with acute humoral xenograft rejection. If immunosuppressive therapy is inadequate, the development of high levels of T cell-dependent elicited anti-pig IgG similarly results in graft destruction, though classical acute cellular rejection is rarely seen. Vascular endothelial activation by low levels of anti-nonGal antibody, coupled with dysregulation of the coagulation-anticoagulation systems between pigs and primates, leads to a thrombotic microangiopathy in the graft that may be associated with a consumptive coagulopathy in the recipient. The most successful approach to overcoming these barriers is by genetically-engineering the pig to provide it with resistance to the human humoral and cellular immune responses and to correct the coagulation discrepancies between the two species. Organs and cells from pigs that (i) do not express the important Gal antigen, (ii) express a human complement-regulatory protein, and (iii) express a human coagulation-regulatory protein, when combined with an effective immunosuppressive regimen, have been associated with prolonged pig graft survival in nonhuman primates.
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Affiliation(s)
- David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Burcin Ekser
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Joseph Tector
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
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Yoon YI, Song GW, Lee SG, Hwang S, Ahn CS, Kim KH, Moon DB, Ha TY, Jung DH, Park GC, Namgung JM, Park YH, Park CS, Park HW, Kang SH, Jung BH. Analysis of Biliary Stricture after ABO Incompatible Adult Living Donor Liver Transplantation. KOREAN JOURNAL OF TRANSPLANTATION 2012. [DOI: 10.4285/jkstn.2012.26.4.277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Young-In Yoon
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Gi-Won Song
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sung-Gyu Lee
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Shin Hwang
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chul-Soo Ahn
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Ki-Hun Kim
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Deok-Bog Moon
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Tae-Yong Ha
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Dong-Hwan Jung
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Gil-Chun Park
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jung-Man Namgung
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Yo-Han Park
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chun-Soo Park
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyoung-Woo Park
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sung-Hwa Kang
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Bo-Hyun Jung
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Abstract
The field of heart transplantation has seen significant progress in the past 40 years. However, the breakthroughs in long-term outcome have seen stagnation in the past decade. Through advances in genomics and transcriptomics, there is hope that an era of personalized transplant therapy lies in the future. To see where heart transplantation truly fits into the long term, searching for and understanding the alternative approaches for heart failure therapy is both important and inevitable. The application of mechanical circulatory support has contributed to the largest advancement in treatment of end stage heart failure. It has already been approved for destination therapy of heart failure, and greater portability and ease of use of the device will be the future trend. Although it is still not prime time for stem cell therapy, clinical experiences have already suggested its potential therapeutic effects. And finally, whole organ engineering is on the horizon as new techniques have opened the way for this to proceed. In the end, progress on alternative therapies largely depends on our deeper understanding of the mechanisms of heart failure and how to prevent it.
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Dons EM, Montoya C, Long CE, Hara H, Echeverri GJ, Ekser B, Ezzelarab C, Medellin DR, van der Windt DJ, Murase N, Rigatti LH, Wagner R, Wolf RF, Ezzelarab M, West LJ, Ijzermans JNM, Cooper DKC. T-cell-based immunosuppressive therapy inhibits the development of natural antibodies in infant baboons. Transplantation 2012; 93:769-76. [PMID: 22441321 PMCID: PMC3776575 DOI: 10.1097/tp.0b013e3182481168] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND We set out to determine whether B-cell tolerance to A/B-incompatible alloantigens and pig xenoantigens could be achieved in infant baboons. METHODS Artery patch grafts were implanted in the abdominal aorta in 3-month-old baboons using A/B-incompatible (AB-I) allografts or wild-type pig xenografts (pig). Group 1 (Gp1) (controls, n=6) received no immunosuppressive therapy (IS) and no graft. Gp2 (n=2) received an AB-I or pig graft but no IS. Gp3 received AB-I grafts+IS (Gp3A: n=2) or pig grafts+IS (Gp3B: n=2). IS consisted of ATG, anti-CD154mAb, and mycophenolate mofetil until age 8 to 12 months. Gp4 (n=2) received IS only but no graft. RESULTS In Gp1, anti-A/B and cytotoxic anti-pig immunoglobulin-M increased steadily during the first year. Gp2 became sensitized to donor-specific AB-I or pig antigens within 2 weeks. Gp3 and Gp4 infants that received anti-CD154mAb made no or minimal anti-A/B and anti-pig antibodies while receiving IS. DISCUSSION The production of natural anti-A/B and anti-pig antibodies was inhibited by IS with anti-CD154mAb, even in the absence of an allograft or xenograft, suggesting that natural antibodies may not be entirely T-cell independent. These data are in contrast to clinical experience with AB-I allotransplantation in infants, who cease producing only donor-specific antibodies.
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Affiliation(s)
- Eefje M. Dons
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
- Department of Surgery, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Claudia Montoya
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Cassandra E. Long
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Hidetaka Hara
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Gabriel J. Echeverri
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Burcin Ekser
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Corin Ezzelarab
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Dasha Roa Medellin
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Dirk J. van der Windt
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
- Department of Surgery, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Noriko Murase
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Lora H. Rigatti
- Division of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh, PA
| | - Robert Wagner
- Division of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh, PA
| | - Roman F. Wolf
- Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Mohamed Ezzelarab
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Lori J. West
- Department of Pediatrics, Cardiac Transplant Research, University of Alberta, Edmonton, AL, Canada
| | - Jan N. M. Ijzermans
- Department of Surgery, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
| | - David K. C. Cooper
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
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Mueller RJ, Stussi G, Puga Yung G, Nikolic M, Soldini D, Halter J, Meyer-Monard S, Gratwohl A, Passweg JR, Odermatt B, Schanz U, Biedermann BC, Seebach JD. Persistence of recipient-type endothelium after allogeneic hematopoietic stem cell transplantation. Haematologica 2010; 96:119-27. [PMID: 20934999 DOI: 10.3324/haematol.2010.030288] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The possibility that allogeneic hematopoietic stem cell transplantation performed across the ABO blood group-barrier is associated with an increase of graft-versus-host disease, in particular endothelial damage, has not been elucidated so far. For this reason, we investigated the level of endothelial cell chimerism after allogeneic hematopoietic stem cell transplantation in order to delineate the role of hematopoietic stem cells in endothelial replacement. DESIGN AND METHODS The frequency of donor-derived endothelial cells was analyzed in 52 hematopoietic stem cell transplant recipients, in 22 normal skin biopsies, in 12 skin samples affected by graft-versus-host disease, various tissues from five autopsies and four secondary solid tumors by ABH immunohistochemistry, XY fluorescence in situ hybridization and short tandem repeat analysis of laser captured endothelial cells. RESULTS Skin biopsies from two patients transplanted with minor ABO-incompatible grafts (i.e. O in A) showed 3.3% and 0.9% H antigen-positive donor-derived endothelial cells by ABH immunohistochemistry. Tumor biopsies from two recipients showed 1.2% and 2.5% donor-derived endothelial cells by combined immunohistochemistry/ fluorescence in situ hybridization. All other skin samples, heart, liver, bone-marrow, and tumor tissues failed to reveal donor-type endothelial cells up to several years after ABO-incompatible hematopoietic stem cell transplantation. CONCLUSIONS Endothelial cell replacement by bone marrow-derived donor cells after allogeneic hematopoietic stem cell transplantation is a rare event. It does not seem to represent a major mechanism of physiological in vivo blood vessel formation, tumor neoangiogenesis, vascular repair after graft-versus-host disease episodes or acceptance of ABO-incompatible grafts.
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Affiliation(s)
- Regula J Mueller
- Laboratory for Transplantation Immunology, University Hospital, Zurich, Switzerland
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Ekser B, Gridelli B, Tector AJ, Cooper DKC. Pig liver xenotransplantation as a bridge to allotransplantation: which patients might benefit? Transplantation 2009; 88:1041-9. [PMID: 19898198 PMCID: PMC2778799 DOI: 10.1097/tp.0b013e3181ba0555] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Acute liver failure is a potentially devastating clinical syndrome that, without liver transplantation (Tx), is associated with high mortality. Rapid deterioration in clinical status and a shortage of deceased human organs prohibits liver Tx in many patients. Bridging to liver Tx has been attempted by various approaches, for example, bioartificial liver support, extracorporeal pig liver perfusion, and hepatocyte Tx, but none of these approaches has convincingly improved patient survival. The orthotopic Tx of a genetically engineered pig liver could theoretically provide successful bridging. Immediate availability, perfect metabolic condition, adequate size-match and hepatocyte mass, and freedom from potentially pathogenic microorganisms could be assured. The advantages and disadvantages of bridging by pig liver Tx compared with other approaches are discussed. The selection of patients for an initial clinical trial of pig liver Tx would be similar to that of various prior trials in patients experiencing rapid and severe deterioration in liver function. The ability to give truly informed consent for a pig bridging procedure at the time of listing for liver Tx renders the patient with acute-on-chronic liver failure or primary allograft failure is a preferable candidate for this procedure than a patient who is admitted urgently with acute (fulminant) liver failure in whom consent may not be possible. Although several barriers to successful pig organ xenoTx remain, for example, coagulation dysfunction between pig and primate, if these can be resolved by further genetic engineering of the organ-source pigs, a pig liver may prove life saving to patients dying rapidly of liver failure.
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Affiliation(s)
- Burcin Ekser
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
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Abstract
PURPOSE OF REVIEW To review the latest development in cardiac xenotransplantation in small and large animal models and related in-vitro studies. RECENT FINDINGS With the recent introduction of alpha1,3-galactosyltransferase gene-knockout (GT-KO) pig organs for xenotransplantation, improved cardiac graft survival has been obtained. However, this experience has demonstrated the importance of pig antigens other than Galalpha1,3Gal (Gal) antigens (so-called nonGal antigens) as targets for primate anti-pig antibodies. Several in-vitro studies have confirmed that, although the incidence and levels of anti-nonGal antibodies in nonhuman primates and humans are significantly less when compared with total anti-pig antibodies (i.e., anti-Gal + anti-nonGal), they can result in complement-mediated lysis of GT-KO pig cells. More recently, it has been demonstrated that regulatory T cells suppress the cellular xenogeneic response, thus potentially preventing or reducing T-cell-mediated rejection. The importance of thrombotic microangiopathy as a feature of the immune/inflammatory response and incompatibilities between the coagulation-anticoagulation systems of pig and primate are receiving increasing attention. Development of GT-KO pigs transgenic for one or more 'antithrombotic' genes, for example, CD39 or tissue factor pathway inhibitor, may contribute to overcoming these problems. SUMMARY Although GT-KO pigs have provided an advance over wild-type pigs as a source of organs for transplantation into primates, further genetic modification of GT-KO pigs is required to overcome the remaining immune barriers before a clinical trial of cardiac xenotransplantation can be contemplated.
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Abstract
PURPOSE OF REVIEW We review recent insights into the mechanisms and prevalence of accommodation. Accommodation refers to an acquired resistance of an organ graft to humoral injury and rejection. RECENT FINDINGS Accommodation has been postulated to reflect changes in antibodies, control of complement and/or acquired resistance to injury by antibodies, complement or other factors. We discuss the importance of these mechanisms, highlighting new conclusions. SUMMARY Accommodation may be a common, perhaps the most common, outcome of organ transplantation and, in some systems, a predictable outcome of organ xenotransplantation. Further understanding of how accommodation is induced and by what mechanisms it is manifest and maintained could have a profound impact on transplantation in general and perhaps on other fields.
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Affiliation(s)
- Raymond J Lynch
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, USA
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The Role of Graft and Host Accommodation in a Hamster-to-Rat Cardiac Transplantation Model. Transplantation 2008; 85:112-7. [DOI: 10.1097/01.tp.0000296030.88283.92] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Cooper DK. Frankenswine, or bringing home the bacon: How close are we to clinical trials in xenotransplantation? Organogenesis 2008; 4:1-10. [PMID: 19279708 DOI: 10.4161/org.5383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 01/31/2008] [Indexed: 11/19/2022] Open
Abstract
Xenotransplantation-specifically from pig into human-could resolve the critical shortage of organs, tissues and cells for clinical transplantation. Genetic engineering techniques in pigs are relatively well-developed and to date have largely been aimed at producing pigs that either (1) express high levels of one or more human complement-regulatory protein(s), such as decay-accelerating factor or membrane cofactor protein, or (2) have deletion of the gene responsible for the expression of the oligosaccharide, Galalpha1,3Gal (Gal), the major target for human anti-pig antibodies, or (3) have both manipulations. Currently the transplantation of pig organs in adequately-immunosuppressed baboons results in graft function for periods of 2-6 months (auxiliary hearts) and 2-3 months (life-supporting kidneys). Pig islets have maintained normoglycemia in diabetic monkeys for >6 months. The remaining immunologic barriers to successful xenotransplantation are discussed, and brief reviews made of (1) the potential risk of the transmission of an infectious microorganism from pig to patient and possibly to the public at large, (2) the potential physiologic incompatibilities between a pig organ and its human counterpart, (3) the major ethical considerations of clinical xenotransplantation, and (4) the possible alternatives that compete with xenotransplantation in the field of organ or cell replacement, such as mechanical devices, tissue engineering, stem cell biology and organogenesis. Finally, the proximity of clinical trials is discussed. Islet xenotransplantation is already at the stage where clinical trials are actively being considered, but the transplantation of pig organs will probably require further genetic modifications to be made to the organ-source pigs to protect their tissues from the coagulation/anticoagulation dysfunction that plays a significant role in pig graft failure after transplantation in primates.
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Affiliation(s)
- David Kc Cooper
- Thomas E. Starzl Transplantation Institute; Department of Surgery; University of Pittsburgh; Pittsburgh, Pennsylvania USA
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Flow Cytometric Measurement of ABO Antibodies in ABO-Incompatible Living Donor Kidney Transplantation. Transplantation 2007; 84:S20-3. [DOI: 10.1097/01.tp.0000296646.17845.12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Rood PPM, Tai HC, Hara H, Long C, Ezzelarab M, Lin YJ, van der Windt DJ, Busch J, Ayares D, Ijzermans JNM, Wolf RF, Manji R, Bailey L, Cooper DKC. Late onset of development of natural anti-nonGal antibodies in infant humans and baboons: implications for xenotransplantation in infants. Transpl Int 2007; 20:1050-8. [PMID: 17850234 DOI: 10.1111/j.1432-2277.2007.00546.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
If an ABO-incompatible heart is transplanted into an infant before natural antibodies have developed to the specific donor carbohydrate A/B antigen(s), then B-cell tolerance to the donor A/B antigen is achieved, and these antibodies never develop. Anti-carbohydrate antibodies play a role in the rejection of wild type (WT) and alpha1,3-galactosyltransferase gene-knockout (GT-KO) pig xenografts. We investigated development of these antibodies in infant baboons and humans. Serum samples from infant baboons (n = 42) and humans (n = 42) were tested by flow cytometry for immunoglobulin M and immunoglobulin G binding to peripheral blood mononuclear cells from WT and GT-KO pigs, and for complement-dependent cytotoxicity. The presence of anti-blood group antibodies was tested in baboon serum. In infant baboons and humans, cytotoxic anti-Galalpha1,3Gal antibodies develop during the first 3 months, and steadily increase with age, whereas cytotoxic anti-nonGal antibodies are either absent or minimal in the majority of cases throughout the first year of life. Anti-blood group antibodies were not detected before 16 weeks of age. Our data suggest GT-KO pig organ/cell transplants could be carried out in early infancy in the absence of preformed cytotoxic anti-nonGalalpha1,3Gal antibodies.
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Affiliation(s)
- Pleunie P M Rood
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Yang YG, Sykes M. Xenotransplantation: current status and a perspective on the future. Nat Rev Immunol 2007; 7:519-31. [PMID: 17571072 DOI: 10.1038/nri2099] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Xenotransplantation using pigs as the transplant source has the potential to resolve the severe shortage of human organ donors. Although the development of relatively non-toxic immunosuppressive or tolerance-inducing regimens will be required to justify clinical trials using pig organs, recent advances in our understanding of the biology of xenograft rejection and zoonotic infections, and the generation of alpha1,3-galactosyltransferase-deficient pigs have moved this approach closer to clinical application. This Review highlights the major obstacles impeding the translation of xenotransplantation into clinical therapies and the potential solutions, providing a perspective on the future of clinical xenotransplantation.
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Affiliation(s)
- Yong-Guang Yang
- Bone Marrow Transplantation Section, Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA
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21
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Tang AH, Platt JL. Accommodation of grafts: implications for health and disease. Hum Immunol 2007; 68:645-51. [PMID: 17678718 PMCID: PMC2703470 DOI: 10.1016/j.humimm.2007.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 04/05/2007] [Accepted: 04/10/2007] [Indexed: 01/01/2023]
Abstract
Accommodation refers to the acquired resistance of a graft to immune-mediated injury. It is typically observed after antibodies that would cause rejection of a graft are removed from a recipient and then later return. In addition to being induced in this manner, accommodation can occur spontaneously, without depleting antibodies. Indeed, we postulate spontaneous accommodation may be the most common outcome of clinical organ transplantation. The paper reviews the current understanding of accommodation, emphasizing recent advances and important questions. Among the recent advances are the discoveries of potentially broader relevance of accommodation for biology and immunology and pathways by which accommodation may be achieved. To investigate these pathways and to understand how accommodation begins and how it evolves, clinical organ transplants might offer a useful and incisive model.
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Affiliation(s)
- Amy H. Tang
- Transplantation Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Jeffrey L. Platt
- Transplantation Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
- Department of Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
- Department of Pediatrics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Ishida H, Miyamoto N, Shirakawa H, Shimizu T, Tokumoto T, Ishikawa N, Shimmura H, Setoguchi K, Toki D, Iida S, Teraoka S, Takahashi K, Toma H, Yamaguchi Y, Tanabe K. Evaluation of immunosuppressive regimens in ABO-incompatible living kidney transplantation--single center analysis. Am J Transplant 2007; 7:825-31. [PMID: 17250557 DOI: 10.1111/j.1600-6143.2006.01676.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Several protocols allow the successful ABO incompatible living-related kidney transplantation (ABO-ILKT), yet no single method has emerged as the best. We have made several substantial changes to our ABO-ILKT protocol over the past decade and a half and have attempted to determine whether the changes in immunosuppressive agents have resulted in a better outcome. We used methylprednisolone (MP), cyclosporine (CsA), azathioprine (AZ), antilymphocyte globulin (ALG) and deoxyspergualine (DSG) in the 105 cases of ABO-ILKT (group 1) between 1989 and 1999, and MP, tacrolimus (FK506), mycophenolate mofetil (MMF) in the 117 cases of ABO-ILKT (group 2) between 2000 and 2004. We compared the patient and graft survival rates as well as the incidence rate of acute rejection in these two eras, when different regimens were used. There were significant differences in the 1- and 5-year graft survival rates between groups 1 and 2 (1-year: 78% in group 1 vs. 94% in group 2; 5-year: 73% in group 1 vs. 90% in group 2, p = 0.008). Also, a higher incidence rate of acute rejection was significantly observed in group 1 (50/105, 48%) than in group 2 (18/117, 15%) (p < 0.001). We conclude that the FK/MMF combination regimen provides excellent graft survival results in ABO-ILKT.
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Affiliation(s)
- H Ishida
- Department of Urology, Tokyo Women's Medical University, Tokyo, Japan.
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Affiliation(s)
- Reto M Baertschiger
- Surgical Research Unit, Department of Surgery, University Hospital Geneva, Geneva, Switzerland
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