1
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Hara H, Foote JB, Hansen-Estruch C, Bikhet MH, Nguyen HQ, Javed M, Oscherwitz M, Collins DE, Ayares D, Yamamoto T, King TW, Cooper DK. In vitro and in vivo immune assessments of genetically-engineered pig skin grafts in New World (squirrel) monkeys. Xenotransplantation 2023; 30:e12832. [PMID: 37870485 PMCID: PMC10843142 DOI: 10.1111/xen.12832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 09/19/2023] [Accepted: 10/05/2023] [Indexed: 10/24/2023]
Abstract
Half a million patients in the USA alone require treatment for burns annually. Following an extensive burn, it may not be possible to provide sufficient autografts in a single setting. Genetic manipulations (GM) of pigs offer the possibility of reducing primate humoral and cellular rejection of pig skin xenografts and thus extending graft survival. We compared the survival of skin grafts from pigs with 9-GM with that of autografts and allografts in squirrel monkeys. Monitoring for rejection was by (1) macroscopic examination, (2) histopathological examination of skin biopsies, and (3) measurement of anti-monkey and anti-pig IgM and IgG antibodies. Autografts (n = 5) survived throughout the 28 days of follow-up without histopathological features of rejection. Median survival of allografts (n = 6) was 14 days and of pig xenografts (n = 12) 21 days. Allotransplantation was associated with an increase in anti-monkey IgM, but the anticipated subsequent rise in IgG had not yet occurred at the time of euthanasia. Pig grafts were associated with increases in anti-pig IgM and IgG. In all cases, histopathologic features of rejection were similar. 9-GM pig skin xenografts survive at least as long as monkey skin allografts (and trended to survive longer), suggesting that they are a realistic clinical option for the temporary treatment of burns. Although monkeys with pig skin grafts developed anti-pig IgM and IgG antibodies, these did not cross-react with monkey antigens, indicating that a primary 9-GM pig skin graft would not be detrimental to a subsequent monkey skin allograft.
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Affiliation(s)
- Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jeremy B. Foote
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Christophe Hansen-Estruch
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mohamed H. Bikhet
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Huy Q. Nguyen
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mariyam Javed
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Max Oscherwitz
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dalis E. Collins
- Animal Resources Program, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Takayuki Yamamoto
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Timothy W. King
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David K.C. Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
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2
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Anand RP, Layer JV, Heja D, Hirose T, Lassiter G, Firl DJ, Paragas VB, Akkad A, Chhangawala S, Colvin RB, Ernst RJ, Esch N, Getchell K, Griffin AK, Guo X, Hall KC, Hamilton P, Kalekar LA, Kan Y, Karadagi A, Li F, Low SC, Matheson R, Nehring C, Otsuka R, Pandelakis M, Policastro RA, Pols R, Queiroz L, Rosales IA, Serkin WT, Stiede K, Tomosugi T, Xue Y, Zentner GE, Angeles-Albores D, Chris Chao J, Crabtree JN, Harken S, Hinkle N, Lemos T, Li M, Pantano L, Stevens D, Subedar OD, Tan X, Yin S, Anwar IJ, Aufhauser D, Capuano S, Kaufman DB, Knechtle SJ, Kwun J, Shanmuganayagam D, Markmann JF, Church GM, Curtis M, Kawai T, Youd ME, Qin W. Design and testing of a humanized porcine donor for xenotransplantation. Nature 2023; 622:393-401. [PMID: 37821590 PMCID: PMC10567564 DOI: 10.1038/s41586-023-06594-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 08/31/2023] [Indexed: 10/13/2023]
Abstract
Recent human decedent model studies1,2 and compassionate xenograft use3 have explored the promise of porcine organs for human transplantation. To proceed to human studies, a clinically ready porcine donor must be engineered and its xenograft successfully tested in nonhuman primates. Here we describe the design, creation and long-term life-supporting function of kidney grafts from a genetically engineered porcine donor transplanted into a cynomolgus monkey model. The porcine donor was engineered to carry 69 genomic edits, eliminating glycan antigens, overexpressing human transgenes and inactivating porcine endogenous retroviruses. In vitro functional analyses showed that the edited kidney endothelial cells modulated inflammation to an extent that was indistinguishable from that of human endothelial cells, suggesting that these edited cells acquired a high level of human immune compatibility. When transplanted into cynomolgus monkeys, the kidneys with three glycan antigen knockouts alone experienced poor graft survival, whereas those with glycan antigen knockouts and human transgene expression demonstrated significantly longer survival time, suggesting the benefit of human transgene expression in vivo. These results show that preclinical studies of renal xenotransplantation could be successfully conducted in nonhuman primates and bring us closer to clinical trials of genetically engineered porcine renal grafts.
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Affiliation(s)
| | | | | | - Takayuki Hirose
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Grace Lassiter
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel J Firl
- eGenesis, Cambridge, MA, USA
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | | | - Robert B Colvin
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | | | | | | | | | | | - Ahmad Karadagi
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Feng Li
- eGenesis, Cambridge, MA, USA
| | | | - Rudy Matheson
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Ryo Otsuka
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | - Ivy A Rosales
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - Toshihide Tomosugi
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Imran J Anwar
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - David Aufhauser
- Department of Surgery, Division of Transplantation, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Saverio Capuano
- Wisconsin National Primate Research Center, Madison, WI, USA
| | - Dixon B Kaufman
- Department of Surgery, Division of Transplantation, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Stuart J Knechtle
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Jean Kwun
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | | | - James F Markmann
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA
| | | | - Tatsuo Kawai
- Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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3
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Cooper DKC, Raza SS, Chaban R, Pierson RN. Shooting for the moon: Genome editing for pig heart xenotransplantation. J Thorac Cardiovasc Surg 2023; 166:973-980. [PMID: 35659123 PMCID: PMC10124774 DOI: 10.1016/j.jtcvs.2022.04.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/04/2022] [Accepted: 04/16/2022] [Indexed: 10/18/2022]
Abstract
Gene-edited pigs could eventually provide organs that are safely and effectively protected from the human immune response without exogenous immunosuppression. Genome editing technology has revolutionized heart xenotransplantation and made transplantation of bioengineered pig hearts into humans a possibility. This first clinical application resulted from a tremendous amount of research. Dramatic early attempts of clinical cardiac xenotransplantation during the last century paved the way to modern xenotransplantation using bioengineered pig hearts. It appears that such genome-edited hearts will be most suitable for neonates and infants because of their immature immune system. The bioengineered pig heart may also be used as a bridge to human heart transplantation, avoiding the risk of thromboembolic events of durable ventricular assist devises in these young children. It is also intriguing to think that bioengineered hearts using pigs as a host may result in a new source of donor hearts that would not evoke the human immune response and minimize, if not eliminate, the need for immunosuppression. It this issue of the Journal, a group of experts led by Dr Cooper, whose personal work spans over 50 years of heart transplantation research, outline the current state of the genome editing of bioengineered hearts and discuss the prospects of clinical application.
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Affiliation(s)
- David K C Cooper
- Center for Transplantation Sciences, Massachusetts General Hospital and Harvard Medical School, Boston, Mass
| | | | - Ryan Chaban
- Center for Transplantation Sciences, Massachusetts General Hospital and Harvard Medical School, Boston, Mass; Department of Cardiovascular Surgery, University Hospital of Johannes Gutenberg University, Mainz, Germany.
| | - Richard N Pierson
- Center for Transplantation Sciences, Massachusetts General Hospital and Harvard Medical School, Boston, Mass
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4
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Chornenkyy Y, Yamamoto T, Hara H, Stowell SR, Ghiran I, Robson SC, Cooper DKC. Future prospects for the clinical transfusion of pig red blood cells. Blood Rev 2023; 61:101113. [PMID: 37474379 PMCID: PMC10968389 DOI: 10.1016/j.blre.2023.101113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/23/2023] [Accepted: 07/09/2023] [Indexed: 07/22/2023]
Abstract
Transfusion of allogeneic human red blood cell (hRBCs) is limited by supply and compatibility between individual donors and recipients. In situations where the blood supply is constrained or when no compatible RBCs are available, patients suffer. As a result, alternatives to hRBCs that complement existing RBC transfusion strategies are needed. Pig RBCs (pRBCs) could provide an alternative because of their abundant supply, and functional similarities to hRBCs. The ability to genetically modify pigs to limit pRBC immunogenicity and augment expression of human 'protective' proteins has provided major boosts to this research and opens up new therapeutic avenues. Although deletion of expression of xenoantigens has been achieved in genetically-engineered pigs, novel genetic methods are needed to introduce human 'protective' transgenes into pRBCs at the high levels required to prevent hemolysis and extend RBC survival in vivo. This review addresses recent progress and examines future prospects for clinical xenogeneic pRBC transfusion.
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Affiliation(s)
- Yevgen Chornenkyy
- Department of Pathology, McGaw Medical Center of Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Takayuki Yamamoto
- Center for Transplantation Science, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA; Division of Transplantation, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
| | - Hidetaka Hara
- College of Veterinary Medicine, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Sean R Stowell
- Joint Program in Transfusion Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ionita Ghiran
- Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | - Simon C Robson
- Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | - David K C Cooper
- Center for Transplantation Science, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
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5
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Habibabady Z, McGrath G, Kinoshita K, Maenaka A, Ikechukwu I, Elias GF, Zaletel T, Rosales I, Hara H, Pierson RN, Cooper DKC. Antibody-mediated rejection in xenotransplantation: Can it be prevented or reversed? Xenotransplantation 2023; 30:e12816. [PMID: 37548030 PMCID: PMC11101061 DOI: 10.1111/xen.12816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/19/2023] [Accepted: 07/26/2023] [Indexed: 08/08/2023]
Abstract
Antibody-mediated rejection (AMR) is the commonest cause of failure of a pig graft after transplantation into an immunosuppressed nonhuman primate (NHP). The incidence of AMR compared to acute cellular rejection is much higher in xenotransplantation (46% vs. 7%) than in allotransplantation (3% vs. 63%) in NHPs. Although AMR in an allograft can often be reversed, to our knowledge there is no report of its successful reversal in a pig xenograft. As there is less experience in preventing or reversing AMR in models of xenotransplantation, the results of studies in patients with allografts provide more information. These include (i) depletion or neutralization of serum anti-donor antibodies, (ii) inhibition of complement activation, (iii) therapies targeting B or plasma cells, and (iv) anti-inflammatory therapy. Depletion or neutralization of anti-pig antibody, for example, by plasmapheresis, is effective in depleting antibodies, but they recover within days. IgG-degrading enzymes do not deplete IgM. Despite the expression of human complement-regulatory proteins on the pig graft, inhibition of systemic complement activation may be necessary, particularly if AMR is to be reversed. Potential therapies include (i) inhibition of complement activation (e.g., by IVIg, C1 INH, or an anti-C5 antibody), but some complement inhibitors are not effective in NHPs, for example, eculizumab. Possible B cell-targeted therapies include (i) B cell depletion, (ii) plasma cell depletion, (iii) modulation of B cell activation, and (iv) enhancing the generation of regulatory B and/or T cells. Among anti-inflammatory agents, anti-IL6R mAb and TNF blockers are increasingly being tested in xenotransplantation models, but with no definitive evidence that they reverse AMR. Increasing attention should be directed toward testing combinations of the above therapies. We suggest that treatment with a systemic complement inhibitor is likely to be most effective, possibly combined with anti-inflammatory agents (if these are not already being administered). Ultimately, it may require further genetic engineering of the organ-source pig to resolve the problem entirely, for example, knockout or knockdown of SLA, and/or expression of PD-L1, HLA E, and/or HLA-G.
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Affiliation(s)
- Zahra Habibabady
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Gannon McGrath
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Kohei Kinoshita
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Akihiro Maenaka
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Ileka Ikechukwu
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Gabriela F. Elias
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Tjasa Zaletel
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Ivy Rosales
- Department of Pathology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Hidetaka Hara
- Yunnan Xenotransplantation Engineering Research Center, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Richard N. Pierson
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - David K. C. Cooper
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
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6
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Hara H, Yamamoto T, Wei HJ, Cooper DK. What Have We Learned From In Vitro Studies About Pig-to-primate Organ Transplantation? Transplantation 2023; 107:1265-1277. [PMID: 36536507 PMCID: PMC10205677 DOI: 10.1097/tp.0000000000004458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Natural preformed and de novo antibodies against pig antigens are a major cause of pig xenograft rejection in nonhuman primates (NHPs). In vivo studies in pig-to-NHP models are time consuming. In vitro assays, for example, antibody binding to pig cells, complement-dependent cytotoxicity assays, provide valuable information quickly and inexpensively. Using in vitro assays for several years, it has been documented that (1) during the first year of life, humans and NHPs develop anti-wild-type pig antibodies, but humans develop no or minimal antibody to triple-knockout (TKO) pig cells. (2) Some adult humans have no or minimal antibodies to TKO pig cells and are therefore unlikely to rapidly reject a TKO organ, particularly if the organ also expresses human "protective" proteins. (3) There is good correlation between immunoglobulin (Ig)M (but no t IgG) binding and complement injury. (4) All Old World NHPs develop antibodies to TKO pig cells and are not optimal recipients of TKO organs. (5) galactosyltransferase gene-knockout/β4GalNT2KO pigs are preferred for Old World NHPs. (6) Humans develop anti-pig IgE and IgA antibodies against pig cells, but their role remains uncertain. (7) In a small percentage of allosensitized humans, antibodies that cross-react with swine leukocyte antigens may be detrimental to a pig organ xenograft. (8) Prior sensitization to pig antigens is unlikely to be detrimental to a subsequent allograft. (9) Deletion of expression of Gal and Neu5Gc is associated with a reduction in the T-cell response to pig cells. All of these valuable observations have largely predicted the results of in vivo studies.
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Affiliation(s)
- Hidetaka Hara
- College of Veterinary Medicine, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Takayuki Yamamoto
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Hong-Jiang Wei
- College of Veterinary Medicine, Yunnan Agricultural University, Kunming, Yunnan, China
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
| | - David K.C. Cooper
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital/Harvard Medical School, Boston, MA
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Cooper DKC, Pierson RN. Milestones on the path to clinical pig organ xenotransplantation. Am J Transplant 2023; 23:326-335. [PMID: 36775767 PMCID: PMC10127379 DOI: 10.1016/j.ajt.2022.12.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/20/2022] [Accepted: 12/28/2022] [Indexed: 01/19/2023]
Abstract
Progress in pig organ xenotransplantation has been made largely through (1) genetic engineering of the organ-source pig to protect its tissues from the human innate immune response, and (2) development of an immunosuppressive regimen based on blockade of the CD40/CD154 costimulation pathway to prevent the adaptive immune response. In the 1980s, after transplantation into nonhuman primates (NHPs), wild-type (genetically unmodified) pig organs were rejected within minutes or hours. In the 1990s, organs from pigs expressing a human complement-regulatory protein (CD55) transplanted into NHPs receiving intensive conventional immunosuppressive therapy functioned for days or weeks. When costimulation blockade was introduced in 2000, the adaptive immune response was suppressed more readily. The identification of galactose-α1,3-galactose as the major antigen target for human and NHP anti-pig antibodies in 1991 allowed for deletion of expression of galactose-α1,3-galactose in 2003, extending pig graft survival for up to 6 months. Subsequent gene editing to overcome molecular incompatibilities between the pig and primate coagulation systems proved additionally beneficial. The identification of 2 further pig carbohydrate xenoantigens allowed the production of 'triple-knockout' pigs that are preferred for clinical organ transplantation. These combined advances enabled the first clinical pig heart transplant to be performed and opened the door to formal clinical trials.
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Affiliation(s)
- David K C Cooper
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA.
| | - Richard N Pierson
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA
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8
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Cooper DKC, Habibabady Z, Kinoshita K, Hara H, Pierson RN. The respective relevance of sensitization to alloantigens and xenoantigens in pig organ xenotransplantation. Hum Immunol 2023; 84:18-26. [PMID: 35817653 PMCID: PMC10154072 DOI: 10.1016/j.humimm.2022.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/14/2022] [Accepted: 06/20/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Antibody-mediated rejection is a major cause of graft injury and contributes to failure of pig xenografts in nonhuman primates (NHPs). Most 'natural' or elicited antibodies found in humans and NHPs are directed against pig glycan antigens, but antibodies binding to swine leukocyte antigens (SLA) have also been detected. Of clinical importance is (i) whether the presence of high levels of antibodies directed towards human leukocyte antigens (HLA) (i.e., high panel-reactive antibodies) would be detrimental to the outcome of a pig organ xenograft; and (ii) whether, in the event of sensitization to pig antigens, a subsequent allotransplant would be at increased risk of graft failure due to elicited anti-pig antibodies that cross-react with human HLA or other antigens. SUMMARY A literature review of pig-to-primate studies indicates that relatively few highly-HLA-sensitized humans have antibodies that cross-react with pigs, predicting that most would not be at increased risk of rejecting an organ xenograft. Furthermore, the existing evidence indicates that sensitization to pig antigens will probably not elicit increased alloantibody titers; if so, 'bridging' with a pig organ could be carried out without increased risk of subsequent antibody-mediated allograft failure. KEY MESSAGE These issues have important implications for the design and conduct of clinical xenotransplantation trials.
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Affiliation(s)
- D K C Cooper
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
| | - Z Habibabady
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - K Kinoshita
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - H Hara
- Yunnan Xenotransplantation Engineering Research Center, Yunnan Agricultural University, Kunming, Yunnan, China
| | - R N Pierson
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
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9
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Zhou Q, Li T, Wang K, Zhang Q, Geng Z, Deng S, Cheng C, Wang Y. Current status of xenotransplantation research and the strategies for preventing xenograft rejection. Front Immunol 2022; 13:928173. [PMID: 35967435 PMCID: PMC9367636 DOI: 10.3389/fimmu.2022.928173] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/07/2022] [Indexed: 12/13/2022] Open
Abstract
Transplantation is often the last resort for end-stage organ failures, e.g., kidney, liver, heart, lung, and pancreas. The shortage of donor organs is the main limiting factor for successful transplantation in humans. Except living donations, other alternatives are needed, e.g., xenotransplantation of pig organs. However, immune rejection remains the major challenge to overcome in xenotransplantation. There are three different xenogeneic types of rejections, based on the responses and mechanisms involved. It includes hyperacute rejection (HAR), delayed xenograft rejection (DXR) and chronic rejection. DXR, sometimes involves acute humoral xenograft rejection (AHR) and cellular xenograft rejection (CXR), which cannot be strictly distinguished from each other in pathological process. In this review, we comprehensively discussed the mechanism of these immunological rejections and summarized the strategies for preventing them, such as generation of gene knock out donors by different genome editing tools and the use of immunosuppressive regimens. We also addressed organ-specific barriers and challenges needed to pave the way for clinical xenotransplantation. Taken together, this information will benefit the current immunological research in the field of xenotransplantation.
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Affiliation(s)
- Qiao Zhou
- Department of Rheumatology and Immunology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Ting Li
- Department of Rheumatology, Wenjiang District People’s Hospital, Chengdu, China
| | - Kaiwen Wang
- School of Medicine, Faculty of Medicine and Health, The University of Leeds, Leeds, United Kingdom
| | - Qi Zhang
- School of Medicine, University of Electronics and Technology of China, Chengdu, China
| | - Zhuowen Geng
- School of Medicine, Faculty of Medicine and Health, The University of Leeds, Leeds, United Kingdom
| | - Shaoping Deng
- Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
- Institute of Organ Transplantation, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, Chengdu, China
| | - Chunming Cheng
- Department of Radiation Oncology, James Comprehensive Cancer Center and College of Medicine at The Ohio State University, Columbus, OH, United States
- *Correspondence: Chunming Cheng, ; Yi Wang,
| | - Yi Wang
- Department of Critical Care Medicine, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, Chengdu, China
- *Correspondence: Chunming Cheng, ; Yi Wang,
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10
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Eisenson DL, Hisadome Y, Yamada K. Progress in Xenotransplantation: Immunologic Barriers, Advances in Gene Editing, and Successful Tolerance Induction Strategies in Pig-To-Primate Transplantation. Front Immunol 2022; 13:899657. [PMID: 35663933 PMCID: PMC9157571 DOI: 10.3389/fimmu.2022.899657] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 04/20/2022] [Indexed: 02/05/2023] Open
Abstract
Organ transplantation is the most effective treatment for end stage organ failure, but there are not enough organs to meet burgeoning demand. One potential solution to this organ shortage is xenotransplantation using pig tissues. Decades of progress in xenotransplantation, accelerated by the development of rapid genome editing tools, particularly the advent of CRISPR-Cas9 gene editing technologies, have enabled remarkable advances in kidney and heart xenotransplantation in pig-to-nonhuman primates. These breakthroughs in large animal preclinical models laid the foundation for three recent pig-to-human transplants by three different groups: two kidney xenografts in brain dead recipients deemed ineligible for transplant, and one heart xenograft in the first clinical grade study of pig-to-human transplantation. However, despite tremendous progress, recent data including the first clinical case suggest that gene-modification alone will not overcome all xenogeneic immunologic barriers, and thus an active and innovative immunologic strategy is required for successful xenotransplantation. This review highlights xenogeneic immunologic barriers, advances in gene editing, and tolerance-inducing strategies in pig-to-human xenotransplantation.
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Affiliation(s)
- Daniel L Eisenson
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States.,Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD, United States
| | - Yu Hisadome
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Kazuhiko Yamada
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States.,Department of Surgery, Columbia University Irving Medical Center, New York, NY, United States
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11
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Li T, Feng H, Du J, Xia Q, Cooper DKC, Jiang H, He S, Pan D, Chen G, Wang Y. Serum Antibody Binding and Cytotoxicity to Pig Cells in Chinese Subjects: Relevance to Clinical Renal Xenotransplantation. Front Immunol 2022; 13:844632. [PMID: 35418974 PMCID: PMC8996717 DOI: 10.3389/fimmu.2022.844632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/18/2022] [Indexed: 11/20/2022] Open
Abstract
Kidney xenotransplantation is expected to contribute to resolving the shortage of kidneys from deceased human donors. Although progress in experimental life-supporting pig renal xenotransplantation has been encouraging, there are still issues to be considered before a clinical trial can be initiated. We attempted to clarify some of these by an in vitro study. Blood was drawn from healthy volunteers (Volunteers, n=20), patients with end-stage renal disease (ESRD, n=20) pre-operation (Pre), and on Day 1 (POD 1) and Day 14 (POD 14) after renal allotransplantation, brain-dead organ donors (DBD, n=20), and renal allotransplant recipients who were currently experiencing T cell-mediated rejection (Allo-TCMR, n=20). Serum IgM/IgG binding to, and complement-dependent cytotoxicity (CDC) of, PBMCs and RBCs from (a) wild-type (WT), (b) α1,3-galactosyltransferase gene-knockout (GTKO), (c) GTKO/beta-1,4-N-acety1 galactosaminyltransferase 2-knockout (GTKO/β4GalNT2KO), (d) GTKO/cytidine monophosphate-N-acetylneuraminic acid hydroxylase-knockout (GTKO/CMAHKO), and (e) GTKO/β4GalNT2KO/CMAHKO/hCD55 (TKO/hCD55) pigs were measured by flow cytometry. We obtained the following results: (i) Serum IgM/IgG binding and CDC in Volunteers were significantly greater to WT, GTKO, and GTKO/β4GalNT2KO PBMCs or RBCs than to GTKO/CMAHKO and TKO/hCD55 cells; (ii) ESRD, DBD, and Allo-TCMR serum antibody binding and CDC to WT pig PBMCs were significantly greater than to GTKO, GTKO/β4GalNT2KO, GTKO/CMAHKO, and TKO/hCD55 cells; (iii) antibody binding to GTKO/CMAHKO pig cells was significantly lower in hemodialysis than peritoneal dialysis patients. (iv) Two of twenty allotransplantation recipients' serum IgG binding to GTKO pig PBMCs increased on POD14 compared with Pre, but IgG binding to GTKO pig RBCs did not; (v) In all sera, the lowest antibody binding and CDC were to GTKO/CMAHKO and TKO/CD55 pig cells. We conclude (i) CMAHKO in the pig may be critical to the success of clinical pig kidney xenotransplantation, and may be the most important after GTKO, at least in Chinese patients; (ii) subjects with ESRD, or who are immunosuppressed after kidney allotransplantation, and DBD, have lower levels of antibody binding and CDC to genetically-engineered pig cells than do volunteers; (iii) TKO pigs with selected human 'protective' transgenes, e.g., CD55, are likely to prove to be the optimal sources of kidneys for clinical xenotransplantation.
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Affiliation(s)
- Tao Li
- Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, The Transplantation Institute of Hainan Medical University, Haikou, China
| | - Hao Feng
- Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education and National Health Commission (NHC), Chinese Academy of Medical Sciences, Wuhan, China
| | - Jiaxiang Du
- Genetic Engineering Department, Chengdu Clonorgan Biotechnology Co., Ltd., Chengdu, China
| | - Qiangbing Xia
- Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education and National Health Commission (NHC), Chinese Academy of Medical Sciences, Wuhan, China
| | - David K. C. Cooper
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, United States
| | - Hongtao Jiang
- Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, The Transplantation Institute of Hainan Medical University, Haikou, China
| | - Songzhe He
- Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, The Transplantation Institute of Hainan Medical University, Haikou, China
| | - Dengke Pan
- Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Sichuan Academy of Medical Sciences & Sichuan Provincial People’s Hospital, Chengdu, China
- *Correspondence: Yi Wang, ; Gang Chen, ; Dengke Pan,
| | - Gang Chen
- Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education and National Health Commission (NHC), Chinese Academy of Medical Sciences, Wuhan, China
- *Correspondence: Yi Wang, ; Gang Chen, ; Dengke Pan,
| | - Yi Wang
- Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, The Transplantation Institute of Hainan Medical University, Haikou, China
- Department of Urology, Second Affiliated Hospital of University of South China, Hengyang, China
- *Correspondence: Yi Wang, ; Gang Chen, ; Dengke Pan,
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12
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Cooper DKC, Hara H. "You cannot stay in the laboratory forever"*: Taking pig kidney xenotransplantation from the laboratory to the clinic. EBioMedicine 2021; 71:103562. [PMID: 34517284 PMCID: PMC8441149 DOI: 10.1016/j.ebiom.2021.103562] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/02/2021] [Accepted: 08/16/2021] [Indexed: 11/18/2022] Open
Abstract
Progress in life-supporting kidney transplantation in the genetically-engineered pig-to-nonhuman primate model has been encouraging, with pig kidneys sometimes supporting life for > 1 year. What steps need to be taken by (i) the laboratory team, and (ii) the clinical team to prepare for the first clinical trial? The major topics include (i) what currently-available genetic modifications are optimal to reduce the possibility of graft rejection, (ii) what immunosuppressive therapeutic regimen is optimal, and (iii) what steps need to be taken to minimize the risk of transfer of an infectious microorganism with the graft. We suggest that patients who are unlikely to live long enough to receive a kidney from a deceased human donor would benefit from the opportunity of a period of dialysis-free support by a pig kidney, and the experience gained would enable xenotransplantation to progress much more rapidly than if we remain in the laboratory.
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Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, 752 Lyons-Harrison Research Building, 701 19th Street South, Birmingham, AL 35294, USA.
| | - Hidetaka Hara
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, 752 Lyons-Harrison Research Building, 701 19th Street South, Birmingham, AL 35294, USA
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13
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Obukhova P, Tsygankova S, Chinarev A, Shilova N, Nokel A, Kosma P, Bovin N. Are there specific antibodies against Neu5Gc epitopes in the blood of healthy individuals? Glycobiology 2021; 30:395-406. [PMID: 31897477 DOI: 10.1093/glycob/cwz107] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 12/11/2022] Open
Abstract
Strong discrepancies in published data on the levels and epitope specificities of antibodies against the xenogenic N-glycolyl forms of sialoglycans (Hanganutziu-Deicher Neu5Gcɑ2-3Galβ1-4Glc and related antigens) in healthy donors prompted us to carry out a systematic study in this area using the printed glycan array and other methods. This article summarizes and discusses our published and previously unpublished data, as well as publicly available data from the Consortium for Functional Glycomics. As a result, we conclude that (1) the level of antibodies referred to as anti-Neu5Gc in healthy individuals is low; (2) there are antibodies that seem to interact with Neu5Gc-containing epitopes, but in fact they recognize internal fragments of Neu5Gc-containing glycans (without sialic acids), which served as antigens in the assays used and; (3) a population capable of interacting specifically with Neu5Gc (it does not bind the corresponding NAc analogs) does exist, but it binds the monosaccharide Neu5Gc better than the entire glycans containing it. In other words, in healthy donors, there are populations of antibodies capable of binding the Neu5Gc monosaccharide or the inner core -Galβ1-4Glc, but very few true anti-Neu5Gcɑ2-3Galβ1-4Glc antibodies, i.e., antibodies capable of specifically recognizing the entire trisaccharide.
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Affiliation(s)
- Polina Obukhova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia.,Federal State Budget Institution, National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V.I. Kulakov of the Ministry of Healthcare of Russian Federation, 4 Oparin str., 117997, Moscow, Russia
| | - Svetlana Tsygankova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia
| | - Alexander Chinarev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia
| | - Nadezhda Shilova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia.,Federal State Budget Institution, National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V.I. Kulakov of the Ministry of Healthcare of Russian Federation, 4 Oparin str., 117997, Moscow, Russia.,Semiotik LLC, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia
| | - Alexey Nokel
- Federal State Budget Institution, National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V.I. Kulakov of the Ministry of Healthcare of Russian Federation, 4 Oparin str., 117997, Moscow, Russia.,Semiotik LLC, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, 18 Muthgasse, 1190 Vienna, Austria, and
| | - Nicolai Bovin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, 117997 Moscow, Russia.,Auckland University of Technology, 55 Wellesley Street East, 1010, Auckland, New Zealand
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14
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Ladowski JM, Houp J, Hauptfeld-Dolejsek V, Javed M, Hara H, Cooper DKC. Aspects of histocompatibility testing in xenotransplantation. Transpl Immunol 2021; 67:101409. [PMID: 34015463 PMCID: PMC8197754 DOI: 10.1016/j.trim.2021.101409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/14/2021] [Indexed: 12/16/2022]
Abstract
Xenotransplantation, using genetically-modified pigs for clinical organ transplantation, is a solution to the organ shortage. The biggest barrier to clinical implementation is the antigenicity of pig cells. Humans possess preformed antibody to pig cells that initiate antibody-mediated rejection of pig organs in primates. Advances in genetic engineering have led to the development of a pig lacking the three known glycan xenoantigens (triple-knockout [TKO] pigs). A significant number of human sera demonstrate no antibody binding to TKO pig cells. As a result of the TKO pig's low antigen expression, survival of life-supporting pig organs in immunosuppressed nonhuman primates has significantly increased, and hope has been renewed for clinical trials of xenotransplantation. It is important to understand the context in which xenotransplantation's predecessor, allotransplantation, has been successful, and the steps needed for the success of xenotransplantation. Successful allotransplantation has been based on two main immunological approaches - (i) adequate immunosuppressive therapy, and (ii) careful histocompatibility matching. In vivo studies suggest that the available immunosuppressive regimens are adequate to suppress the human anti-pig cellular response. Methods to evaluate and screen patients for the first clinical xenotransplantation trial are the next challenge. The goal of this review is to summarize the history of histocompatibility testing, and the available tools that can be utilized to determine xenograft histocompatibility.
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Affiliation(s)
- Joseph M Ladowski
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julie Houp
- Histocompatibility Laboratory, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Mariyam Javed
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
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15
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Shu S, Ren J, Song J. Cardiac xenotransplantation: a promising way to treat advanced heart failure. Heart Fail Rev 2020; 27:71-91. [DOI: 10.1007/s10741-020-09989-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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16
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Lu T, Yang B, Wang R, Qin C. Xenotransplantation: Current Status in Preclinical Research. Front Immunol 2020; 10:3060. [PMID: 32038617 PMCID: PMC6989439 DOI: 10.3389/fimmu.2019.03060] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/16/2019] [Indexed: 12/13/2022] Open
Abstract
The increasing life expectancy of humans has led to a growing numbers of patients with chronic diseases and end-stage organ failure. Transplantation is an effective approach for the treatment of end-stage organ failure; however, the imbalance between organ supply and the demand for human organs is a bottleneck for clinical transplantation. Therefore, xenotransplantation might be a promising alternative approach to bridge the gap between the supply and demand of organs, tissues, and cells; however, immunological barriers are limiting factors in clinical xenotransplantation. Thanks to advances in gene-editing tools and immunosuppressive therapy as well as the prolonged xenograft survival time in pig-to-non-human primate models, clinical xenotransplantation has become more viable. In this review, we focus on the evolution and current status of xenotransplantation research, including our current understanding of the immunological mechanisms involved in xenograft rejection, genetically modified pigs used for xenotransplantation, and progress that has been made in developing pig-to-pig-to-non-human primate models. Three main types of rejection can occur after xenotransplantation, which we discuss in detail: (1) hyperacute xenograft rejection, (2) acute humoral xenograft rejection, and (3) acute cellular rejection. Furthermore, in studies on immunological rejection, genetically modified pigs have been generated to bridge cross-species molecular incompatibilities; in the last decade, most advances made in the field of xenotransplantation have resulted from the production of genetically engineered pigs; accordingly, we summarize the genetically modified pigs that are currently available for xenotransplantation. Next, we summarize the longest survival time of solid organs in preclinical models in recent years, including heart, liver, kidney, and lung xenotransplantation. Overall, we conclude that recent achievements and the accumulation of experience in xenotransplantation mean that the first-in-human clinical trial could be possible in the near future. Furthermore, we hope that xenotransplantation and various approaches will be able to collectively solve the problem of human organ shortage.
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Affiliation(s)
- Tianyu Lu
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Bochao Yang
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Ruolin Wang
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Chuan Qin
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
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17
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Abstract
There is a well-known worldwide shortage of deceased human donor organs for clinical transplantation. The transplantation of organs from genetically engineered pigs may prove an alternative solution. In the past 5 years, there have been sequential advances that have significantly increased pig graft survival in nonhuman primates. This progress has been associated with (1) the availability of increasingly sophisticated genetically engineered pigs; (2) the introduction of novel immunosuppressive agents, particularly those that block the second T-cell signal (costimulation blockade); (3) a better understanding of the inflammatory response to pig xenografts; and (4) increasing experience in the management of nonhuman primates with pig organ or cell grafts. The range of investigations required in experimental studies has increased. The standard immunologic assays are still carried out, but increasingly investigations aimed toward other pathobiologic barriers (e.g., coagulation dysregulation and inflammation) have become more important in determining injury to the graft.Now that prolonged graft survival, extending to months or even years, is increasingly being obtained, the function of the grafts can be more reliably assessed. If the source pigs are bred and housed under biosecure isolation conditions, and weaned early from the sow, most microorganisms can be eradicated from the herd. The potential risk of porcine endogenous retrovirus (PERV) infection remains unknown, but is probably small. Attention is being directed toward the selection of patients for the first clinical trials of xenotransplantation.
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Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
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18
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Cooper DKC, Hara H, Iwase H, Yamamoto T, Jagdale A, Kumar V, Mannon RB, Hanaway MJ, Anderson DJ, Eckhoff DE. Clinical Pig Kidney Xenotransplantation: How Close Are We? J Am Soc Nephrol 2019; 31:12-21. [PMID: 31792154 DOI: 10.1681/asn.2019070651] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Patients with ESKD who would benefit from a kidney transplant face a critical and continuing shortage of kidneys from deceased human donors. As a result, such patients wait a median of 3.9 years to receive a donor kidney, by which time approximately 35% of transplant candidates have died while waiting or have been removed from the waiting list. Those of blood group B or O may experience a significantly longer waiting period. This problem could be resolved if kidneys from genetically engineered pigs offered an alternative with an acceptable clinical outcome. Attempts to accomplish this have followed two major paths: deletion of pig xenoantigens, as well as insertion of "protective" human transgenes to counter the human immune response. Pigs with up to nine genetic manipulations are now available. In nonhuman primates, administering novel agents that block the CD40/CD154 costimulation pathway, such as an anti-CD40 mAb, suppresses the adaptive immune response, leading to pig kidney graft survival of many months without features of rejection (experiments were terminated for infectious complications). In the absence of innate and adaptive immune responses, the transplanted pig kidneys have generally displayed excellent function. A clinical trial is anticipated within 2 years. We suggest that it would be ethical to offer a pig kidney transplant to selected patients who have a life expectancy shorter than the time it would take for them to obtain a kidney from a deceased human donor. In the future, the pigs will also be genetically engineered to control the adaptive immune response, thus enabling exogenous immunosuppressive therapy to be significantly reduced or eliminated.
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Affiliation(s)
| | - Hidetaka Hara
- Division of Transplantation, Department of Surgery and
| | - Hayato Iwase
- Division of Transplantation, Department of Surgery and
| | | | | | - Vineeta Kumar
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Roslyn Bernstein Mannon
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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19
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Forneris N, Burlak C. Xenotransplantation literature update, May/June 2019. Xenotransplantation 2019; 26:e12547. [PMID: 31392783 DOI: 10.1111/xen.12547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 07/24/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Nicole Forneris
- Department of Surgery, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Christopher Burlak
- Department of Surgery, University of Minnesota Medical School, Minneapolis, Minnesota
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20
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Breimer ME, Holgersson J. The Structural Complexity and Animal Tissue Distribution of N-Glycolylneuraminic Acid (Neu5Gc)-Terminated Glycans. Implications for Their Immunogenicity in Clinical Xenografting. Front Mol Biosci 2019; 6:57. [PMID: 31428616 PMCID: PMC6690001 DOI: 10.3389/fmolb.2019.00057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/04/2019] [Indexed: 12/13/2022] Open
Abstract
N-Glycolylneuraminic acid (Neu5Gc)-terminated glycans are present in all animal cells/tissues that are already used in the clinic such as bioprosthetic heart valves (BHV) as well as in those that potentially will be xenografted in the future to overcome end stage cell/organ failure. Humans, as a species lack this antigen determinant and can react with an immune response after exposure to Neu5Gc present in these products/cells/tissues. Genetically engineered source animals lacking Neu5Gc has been generated and so has animals that in addition lack the major αGal xenoantigen. The use of cells/tissues/organs from such animals may improve the long-term performance of BHV and allow future xenografting. This review summarizes the present knowledge regarding structural complexity and tissue distribution of Neu5Gc on glycans of cells/tissue/organs already used in the clinic or intended for treatment of end stage organ failure by xenografting. In addition, we briefly discuss the role of anti-Neu5Gc antibodies in the xenorejection process and how knowledge about Neu5Gc structural complexity can be used to design novel diagnostics for anti-Neu5Gc antibody detection.
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Affiliation(s)
- Michael E Breimer
- Department of Surgery, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jan Holgersson
- Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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21
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Perota A, Lagutina I, Duchi R, Zanfrini E, Lazzari G, Judor JP, Conchon S, Bach JM, Bottio T, Gerosa G, Costa C, Galiñanes M, Roussel JC, Padler-Karavani V, Cozzi E, Soulillou JP, Galli C. Generation of cattle knockout for galactose-α1,3-galactose and N-glycolylneuraminic acid antigens. Xenotransplantation 2019; 26:e12524. [PMID: 31115108 PMCID: PMC6852128 DOI: 10.1111/xen.12524] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/27/2019] [Accepted: 04/18/2019] [Indexed: 12/26/2022]
Abstract
Two well‐characterized carbohydrate epitopes are absent in humans but present in other mammals. These are galactose‐α1,3‐galactose (αGal) and N‐glycolylneuraminic acid (Neu5Gc) which are introduced by the activities of two enzymes including α(1,3) galactosyltransferase (encoded by the GGTA1 gene) and CMP‐Neu5Gc hydroxylase (encoded by the CMAH gene) that are inactive in humans but present in cattle. Hence, bovine‐derived products are antigenic in humans who receive bioprosthetic heart valves (BHVs) or those that suffer from red meat syndrome. Using programmable nucleases, we disrupted (knockout, KO) GGTA1 and CMAH genes encoding for the enzymes that catalyse the synthesis of αGal and Neu5Gc, respectively, in both male and female bovine fibroblasts. The KO in clonally selected fibroblasts was detected by polymerase chain reaction (PCR) and confirmed by Sanger sequencing. Selected fibroblasts colonies were used for somatic cell nuclear transfer (SCNT) to produce cloned embryos that were implanted in surrogate recipient heifers. Fifty‐three embryos were implanted in 33 recipients heifers; 3 pregnancies were carried to term and delivered 3 live calves. Primary cell cultures were established from the 3 calves and following molecular analyses confirmed the genetic deletions. FACS analysis showed the double‐KO phenotype for both antigens confirming the mutated genotypes. Availability of such cattle double‐KO model lacking both αGal and Neu5Gc offers a unique opportunity to study the functionality of BHV manufactured with tissues of potentially lower immunogenicity, as well as a possible new clinical approaches to help patients with red meat allergy syndrome due to the presence of these xenoantigens in the diet.
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Affiliation(s)
- Andrea Perota
- Avantea, Laboratory of Reproductive Technologies, Cremona, Italy
| | - Irina Lagutina
- Avantea, Laboratory of Reproductive Technologies, Cremona, Italy
| | - Roberto Duchi
- Avantea, Laboratory of Reproductive Technologies, Cremona, Italy
| | - Elisa Zanfrini
- Avantea, Laboratory of Reproductive Technologies, Cremona, Italy
| | - Giovanna Lazzari
- Avantea, Laboratory of Reproductive Technologies, Cremona, Italy.,Fondazione Avantea, Cremona, Italy
| | - Jean Paul Judor
- Centre de Recherche en Transplantation et Immunologie, UMR 1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France
| | - Sophie Conchon
- Centre de Recherche en Transplantation et Immunologie, UMR 1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France
| | - Jean Marie Bach
- IECM, Immuno-endocrinology, EA4644 Oniris, University of Nantes, USC1383 INRA, Oniris, Nantes, France
| | - Tomaso Bottio
- Cardiac Surgery Unit - Department of Cardiac, Thoracic and Vascular Sciences and Public Health - Padova University School of Medicine and CORIS, Padova, Italy
| | - Gino Gerosa
- Cardiac Surgery Unit - Department of Cardiac, Thoracic and Vascular Sciences and Public Health - Padova University School of Medicine and CORIS, Padova, Italy
| | - Cristina Costa
- Infectious Diseases and Transplantation Division, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain
| | - Manuel Galiñanes
- Reparative Therapy of the Heart, Vall d'Hebron Research Institute (VHIR) and Department of Cardiac Surgery, University Hospital Vall d'Hebron, Autonomous University of Barcelona (AUB), Barcelona, Spain
| | - Jean Christian Roussel
- Department of Thoracic and CardioVascular Surgery, Nantes Hospital University, Nantes, France
| | - Vered Padler-Karavani
- The George S. Wise Faculty of Life Sciences, Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
| | - Emanuele Cozzi
- Transplant Immunology Unit, Padua General Hospital, Padua, Italy
| | - Jean Paul Soulillou
- Centre de Recherche en Transplantation et Immunologie, UMR 1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France
| | - Cesare Galli
- Avantea, Laboratory of Reproductive Technologies, Cremona, Italy.,Fondazione Avantea, Cremona, Italy
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Cooper DKC, Hara H, Iwase H, Yamamoto T, Li Q, Ezzelarab M, Federzoni E, Dandro A, Ayares D. Justification of specific genetic modifications in pigs for clinical organ xenotransplantation. Xenotransplantation 2019; 26:e12516. [PMID: 30989742 PMCID: PMC10154075 DOI: 10.1111/xen.12516] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/11/2019] [Accepted: 03/22/2019] [Indexed: 12/17/2022]
Abstract
Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications. We suggest that a pig with nine genetic modifications (ie, currently available) will provide organs (initially kidneys and hearts) that would function for a clinically valuable period of time, for example, >12 months, after transplantation into patients with end-stage organ failure. The national regulatory authorities, however, will likely require evidence, based on in vitro and/or in vivo experimental data, to justify the inclusion of each individual genetic modification in the pig. We provide data both from our own experience and that of others on the advantages of pigs in which (a) all three known carbohydrate xenoantigens have been deleted (triple-knockout pigs), (b) two human complement-regulatory proteins (CD46, CD55) and two human coagulation-regulatory proteins (thrombomodulin, endothelial cell protein C receptor) are expressed, (c) the anti-apoptotic and "anti-inflammatory" molecule, human hemeoxygenase-1 is expressed, and (d) human CD47 is expressed to suppress elements of the macrophage and T-cell responses. Although many alternative genetic modifications could be made to an organ-source pig, we suggest that the genetic manipulations we identify above will all contribute to the success of the initial clinical pig kidney or heart transplants, and that the beneficial contribution of each individual manipulation is supported by considerable experimental evidence.
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Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - Takayuki Yamamoto
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - Qi Li
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama.,Second Affiliated Hospital, University of South China, Hengyang City, China
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Elena Federzoni
- Exponential Biotherapeutic Engineering, United Therapeutics, LaJolla, California
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In Search of the Ideal Valve: Optimizing Genetic Modifications to Prevent Bioprosthetic Degeneration. Ann Thorac Surg 2019; 108:624-635. [PMID: 30836101 DOI: 10.1016/j.athoracsur.2019.01.054] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/10/2019] [Accepted: 01/21/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Bioprosthetic heart valves undergo structural degeneration and calcification. Similarities exist in the histopathologic features of explanted bioprosthetic valves and rejected pig tissues and organs after xenotransplantation into nonhuman primates. The development of more durable bioprosthetic valves, namely from genetically modified pigs, could negate the need for the insertion of mechanical prostheses in children and young adults with the requirement for life-long anticoagulation and might avoid the need for reoperation in elderly patients. METHODS We reviewed the literature (MedlinePlus, PubMed, Google Scholar) through September 1, 2018, under four key terms: (1) bioprosthetic heart valves, (2) xenograft antigens, (3) immunologic responses to bioprosthetic valves, and (4) genetic modification of xenografts. RESULTS Advances in tissue and organ xenotransplantation have elucidated important immunologic barriers that provide innovative approaches to prevent structural degeneration of bioprosthetic heart valves. The current evidence suggests that bioprosthetic valves derived from genetically modified pigs lacking xenogeneic antigens (namely Gal, Neu5Gc, and Sda), termed triple-knockout pigs, would function considerably longer than current wild-type (genetically unmodified) porcine valves in human recipients. CONCLUSIONS Preclinical and clinical studies to determine the safety and efficacy of triple-knockout porcine bioprosthetic valves will likely establish that they are more resistant to human immune responses and thus less susceptible to structural degeneration.
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Zhang X, Li X, Yang Z, Tao K, Wang Q, Dai B, Qu S, Peng W, Zhang H, Cooper DKC, Dou K. A review of pig liver xenotransplantation: Current problems and recent progress. Xenotransplantation 2019; 26:e12497. [PMID: 30767272 DOI: 10.1111/xen.12497] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/01/2019] [Accepted: 01/07/2019] [Indexed: 12/14/2022]
Abstract
Pig liver xenotransplantation appears to be more perplexing when compared to heart or kidney xenotransplantation, even though great progress has been achieved. The relevant molecular mechanisms involved in xenogeneic rejection, including coagulopathy, and particularly thrombocytopenia, are complex, and need to be systematically investigated. The deletion of expression of Gal antigens in the liver graft highlights the injurious impact of nonGal antigens, which continue to induce humoral rejection. Innate immunity, particularly mediated by macrophages and natural killer cells, interplays with inflammation and coagulation disorders. Kupffer cells and liver sinusoidal endothelial cells (LSECs) together mediate leukocyte, erythrocyte, and platelet sequestration and phagocytosis, which can be exacerbated by increased cytokine production, cell desialylation, and interspecies incompatibilities. The coagulation cascade is activated by release of tissue factor which can be dependent or independent of the xenoreactive immune response. Depletion of endothelial anticoagulants and anti-platelet capacity amplify coagulation activation, and interspecies incompatibilities of coagulation-regulatory proteins facilitate dysregulation. LSECs involved in platelet phagocytosis and transcytosis, coupled with hepatocyte-mediated degradation, are responsible for thrombocytopenia. Adaptive immunity could also be problematic in long-term liver graft survival. Currently, relevant evidence and study results of various genetic modifications to the pig donor need to be fully determined, with the aim of identifying the ideal transgene combination for pig liver xenotransplantation. We believe that clinical trials of pig liver xenotransplantation should initially be considered as a bridge to allotransplantation.
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Affiliation(s)
- Xuan Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Xiao Li
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Zhaoxu Yang
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Kaishan Tao
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Quancheng Wang
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Bin Dai
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Shibin Qu
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Wei Peng
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Hong Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - Kefeng Dou
- Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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Immune Responses of HLA Highly Sensitized and Nonsensitized Patients to Genetically Engineered Pig Cells. Transplantation 2019; 102:e195-e204. [PMID: 29266033 DOI: 10.1097/tp.0000000000002060] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND We investigated in vitro whether HLA highly sensitized patients with end-stage renal disease will be disadvantaged immunologically after a genetically engineered pig kidney transplant. METHODS Blood was drawn from patients with a calculated panel-reactive antibody (cPRA) 99% to 100% (Gp1, n = 10) or cPRA 0% (Gp2, n = 12), and from healthy volunteers (Gp3, n = 10). Serum IgM and IgG binding was measured (i) to galactose-α1-3 galactose and N-glycolylneuraminic acid glycans by enzyme-linked immunosorbent assay, and (ii) to pig red blood cell, pig aortic endothelial cells, and pig peripheral blood mononuclear cell from α1,3-galactosyltransferase gene-knockout (GTKO)/CD46 and GTKO/CD46/cytidine monophosphate-N-acetylneuraminic acid hydroxylase-knockout (CMAHKO) pigs by flow cytometry. (iii) T-cell and B-cell phenotypes were determined by flow cytometry, and (iv) proliferation of T-cell and B-cell carboxyfluorescein diacetate succinimidyl ester-mixed lymphocyte reaction. RESULTS (i) By enzyme-linked immunosorbent assay, there was no difference in IgM or IgG binding to galactose-α1-3 galactose or N-glycolylneuraminic acid between Gps1 and 2, but binding was significantly reduced in both groups compared to Gp3. (ii) IgM and IgG binding in Gps1 and 2 was also significantly lower to GTKO/CD46 pig cells than in healthy controls, but there were no differences between the 3 groups in binding to GTKO/CD46/CMAHKO cells. (iii and iv) Gp1 patients had more memory T cells than Gp2, but there was no difference in T or B cell proliferation when stimulated by any pig cells. The proliferative responses in all 3 groups were weakest when stimulated by GTKO/CD46/CMAHKO pig peripheral blood mononuclear cell. CONCLUSIONS (i) End-stage renal disease was associated with low antipig antibody levels. (ii) Xenoreactivity decreased with increased genetic engineering of pig cells. (iii) High cPRA status had no significant effect on antibody binding or T-cell and B-cell response.
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Smood B, Hara H, Schoel LJ, Cooper DKC. Genetically-engineered pigs as sources for clinical red blood cell transfusion: What pathobiological barriers need to be overcome? Blood Rev 2019; 35:7-17. [PMID: 30711308 DOI: 10.1016/j.blre.2019.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/02/2019] [Accepted: 01/25/2019] [Indexed: 12/27/2022]
Abstract
An alternative to human red blood cells (RBCs) for clinical transfusion would be advantageous, particularly in situations of massive acute blood loss (where availability and compatibility are limited) or chronic hematologic diseases requiring frequent transfusions (resulting in alloimmunization). Ideally, any alternative must be neither immunogenic nor pathogenic, but readily available, inexpensive, and physiologically effective. Pig RBCs (pRBCs) provide a promising alternative due to their several similarities with human RBCs, and our increasing ability to genetically-modify pigs to reduce cellular immunogenicity. We briefly summarize the history of xenotransfusion, the progress that has been made in recent years, and the remaining barriers. These barriers include prevention of (i) human natural antibody binding to pRBCs, (ii) their phagocytosis by macrophages, and (iii) the T cell adaptive immune response (in the absence of exogenous immunosuppressive therapy). Although techniques of genetic engineering have advanced in recent years, novel methods to introduce human transgenes into pRBCs (which do not have nuclei) will need to be developed before clinical trials can be initiated.
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Affiliation(s)
- Benjamin Smood
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Leah J Schoel
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
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Cooper DK, Ezzelarab M, Iwase H, Hara H. Perspectives on the Optimal Genetically Engineered Pig in 2018 for Initial Clinical Trials of Kidney or Heart Xenotransplantation. Transplantation 2018; 102:1974-1982. [PMID: 30247446 PMCID: PMC6249080 DOI: 10.1097/tp.0000000000002443] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
For a clinical trial today, what might realistically be the optimal pig among those currently available? Deletion of expression of the 3 pig carbohydrate antigens, against which humans have natural (preformed) antibodies (triple-knockout pigs), should form the basis of any clinical trial. However, because both complement and coagulation can be activated in the absence of antibody, the expression of human complement- and coagulation-regulatory proteins is likely to be important in protecting the graft further. Any genetic manipulation that might reduce inflammation of the graft, for example, expression of hemeoxygenase-1 or A20, may also be beneficial to the long-term survival of the graft. The transgene for human CD47 is likely to have a suppressive effect on monocyte/macrophage and T-cell activity. Furthermore, deletion of xenoantigen expression and expression of a human complement-regulatory protein are both associated with a reduced T-cell response. Although there are several other genetic manipulations that may reduce the T-cell response further, it seems likely that exogenous immunosuppressive therapy, particularly if it includes costimulation blockade, will be sufficient. We would therefore suggest that, with our present knowledge and capabilities, the optimal pig might be a triple-knockout pig that expressed 1 or more human complement-regulatory proteins, 1 or more human coagulation-regulatory proteins, a human anti-inflammatory transgene, and CD47. Absent or minimal antibody binding is important, but we suggest that the additional insertion of protective human transgenes will be beneficial, and may be essential.
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Affiliation(s)
- David K.C. Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
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Peri S, Kulkarni A, Feyertag F, Berninsone PM, Alvarez-Ponce D. Phylogenetic Distribution of CMP-Neu5Ac Hydroxylase (CMAH), the Enzyme Synthetizing the Proinflammatory Human Xenoantigen Neu5Gc. Genome Biol Evol 2018; 10:207-219. [PMID: 29206915 PMCID: PMC5767959 DOI: 10.1093/gbe/evx251] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2017] [Indexed: 01/25/2023] Open
Abstract
The enzyme CMP-N-acetylneuraminic acid hydroxylase (CMAH) is responsible for the synthesis of N-glycolylneuraminic acid (Neu5Gc), a sialic acid present on the cell surface proteins of most deuterostomes. The CMAH gene is thought to be present in most deuterostomes, but it has been inactivated in a number of lineages, including humans. The inability of humans to synthesize Neu5Gc has had several evolutionary and biomedical implications. Remarkably, Neu5Gc is a xenoantigen for humans, and consumption of Neu5Gc-containing foods, such as red meats, may promote inflammation, arthritis, and cancer. Likewise, xenotransplantation of organs producing Neu5Gc can result in inflammation and organ rejection. Therefore, knowing what animal species contain a functional CMAH gene, and are thus capable of endogenous Neu5Gc synthesis, has potentially far-reaching implications. In addition to humans, other lineages are known, or suspected, to have lost CMAH; however, to date reports of absent and pseudogenic CMAH genes are restricted to a handful of species. Here, we analyze all available genomic data for nondeuterostomes, and 322 deuterostome genomes, to ascertain the phylogenetic distribution of CMAH. Among nondeuterostomes, we found CMAH homologs in two green algae and a few prokaryotes. Within deuterostomes, putatively functional CMAH homologs are present in 184 of the studied genomes, and a total of 31 independent gene losses/pseudogenization events were inferred. Our work produces a list of animals inferred to be free from endogenous Neu5Gc based on the absence of CMAH homologs and are thus potential candidates for human consumption, xenotransplantation research, and model organisms for investigation of human diseases.
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Affiliation(s)
- Sateesh Peri
- Department of Biology, University of Nevada, Reno
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Cooper DKC, Gaston R, Eckhoff D, Ladowski J, Yamamoto T, Wang L, Iwase H, Hara H, Tector M, Tector AJ. Xenotransplantation-the current status and prospects. Br Med Bull 2018; 125:5-14. [PMID: 29228112 PMCID: PMC6487536 DOI: 10.1093/bmb/ldx043] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/28/2017] [Accepted: 11/22/2017] [Indexed: 02/01/2023]
Abstract
Introduction There is a continuing worldwide shortage of organs from deceased human donors for transplantation into patients with end-stage organ failure. Genetically engineered pigs could resolve this problem, and could also provide tissues and cells for the treatment of conditions such as diabetes, Parkinson's disease and corneal blindness. Sources of data The current literature has been reviewed. Areas of agreement The pathobiologic barriers are now largely defined. Research progress has advanced through the increasing availability of genetically engineered pigs and novel immunosuppressive agents. Life-supporting pig kidneys and islets have functioned for months or years in nonhuman primates. Areas of controversy The potential risk of transfer of a pig infectious microorganism to the recipient continues to be debated. Growing points Increased attention is being paid to selection of patients for initial clinical trials. Areas timely for developing research Most of the advances required to justify a clinical trial have now been met.
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Affiliation(s)
- D K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - R Gaston
- Department of Nephrology, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - D Eckhoff
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - J Ladowski
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - T Yamamoto
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - L Wang
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - H Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - H Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - M Tector
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
| | - A J Tector
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA
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Cooper DKC, Ezzelarab MB, Hara H. Low anti-pig antibody levels are key to the success of solid organ xenotransplantation: But is this sufficient? Xenotransplantation 2017; 24. [PMID: 29067714 DOI: 10.1111/xen.12360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/09/2017] [Accepted: 09/26/2017] [Indexed: 12/15/2022]
Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mohamed B Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
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Gao B, Long C, Lee W, Zhang Z, Gao X, Landsittel D, Ezzelarab M, Ayares D, Huang Y, Cooper DKC, Wang Y, Hara H. Anti-Neu5Gc and anti-non-Neu5Gc antibodies in healthy humans. PLoS One 2017; 12:e0180768. [PMID: 28715486 PMCID: PMC5513429 DOI: 10.1371/journal.pone.0180768] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 06/21/2017] [Indexed: 02/03/2023] Open
Abstract
Our group previously investigated the levels of anti-Gal and anti-nonGal IgM and IgG in a cohort of 75 healthy humans of various backgrounds, and found some significant differences related to factors such as age, gender, ABO blood group, diet, vaccination history, and geographic location during childhood. We have now expanded our cohort (n = 84) to investigate the levels of anti-Neu5Gc and anti-nonGal/nonNeu5Gc antibodies in healthy humans. Anti-nonGal and anti-nonGal/nonNeu5Gc human IgM and IgG binding to pRBCs and pAECs from GTKO/CD46 and GTKO/CD46/Neu5GcKO pigs were measured by flow cytometry. Anti-Gal and anti-Neu5Gc IgM and IgG levels were measured by ELISA. In summary, (i) the great majority (almost 100%) of humans had anti-Neu5Gc IgM and IgG antibodies that bound to pAECs and approximately 50% had anti-Neu5Gc antibodies that bound to pRBCs, (ii) there was significantly less human antibody binding to pig cells that did not express either Gal or Neu5Gc compared with those that did not express Gal alone, (iii) the levels of both IgM and IgG binding to GTKO/CD46/Neu5GcKO pRBCs and pAECs were low, (iv) the level of anti-Neu5Gc IgG was higher in men than women, (v) the level did not change with age or diet, and there was some variability associated with (vi) previous vaccination history and (vii) the geographic region in which the individual spent his or her childhood. Our study confirms that human antibody binding to RBCs and AECs from GTKO/CD46/Neu5GcKO pigs is greatly reduced compared to binding to GTKO/CD46 cells. However, all humans appear to have a low level of antibody that binds to pAECs that is not directed to either Gal or Neu5Gc. Our findings require consideration in planning clinical trials of xenotransplantation.
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Affiliation(s)
- Bingsi Gao
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
- Department of Obstetrics and Gynecology, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Whayoung Lee
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Zhongqiang Zhang
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of General Surgery, Second Xiangya Hospital of the Central South University, Changsha, Hunan, China
| | - Xiaotian Gao
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Doug Landsittel
- Department of Biostatistics and Clinical and Translational Science, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - David Ayares
- Revivicor, Blacksburg, VA, United States of America
| | - Yuliang Huang
- Department of Obstetrics and Gynecology, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
| | - David K. C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Yi Wang
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
- * E-mail: (HH); (YW)
| | - Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, United States of America
- * E-mail: (HH); (YW)
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Abstract
Experience with clinical liver xenotransplantation has largely involved the transplantation of livers from nonhuman primates. Experience with pig livers has been scarce. This brief review will be restricted to assessing the potential therapeutic impact of pig liver xenotransplantation in acute liver failure and the remaining barriers that currently do not justify clinical trials. A relatively new surgical technique of heterotopic pig liver xenotransplantation is described that might play a role in bridging a patient with acute liver failure until either the native liver recovers or a suitable liver allograft is obtained. Other topics discussed include the possible mechanisms for the development of the thrombocytopenis that rapidly occurs after pig liver xenotransplantation in a primate, the impact of pig complement on graft injury, the potential infectious risks, and potential physiologic incompatibilities between pig and human. There is cautious optimism that all of these problems can be overcome by judicious genetic manipulation of the pig. If liver graft survival could be achieved in the absence of thrombocytopenia or rejection for a period of even a few days, there may be a role for pig liver transplantation as a bridge to allotransplantation in carefully selected patients.
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Expression of NeuGc on Pig Corneas and Its Potential Significance in Pig Corneal Xenotransplantation. Cornea 2016; 35:105-13. [PMID: 26418433 DOI: 10.1097/ico.0000000000000635] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE Pigs expressing neither galactose-α1,3-galactose (Gal) nor N-glycolylneuraminic acid (NeuGc) take xenotransplantation one step closer to the clinic. Our aims were (1) to document the lack of NeuGc expression on corneas and aortas and cultured endothelial cells [aortic endothelial cells (AECs); corneal (CECs)] of GTKO/NeuGcKO pigs, and (2) to investigate whether the absence of NeuGc reduced human antibody binding to the tissues and cells. METHODS Wild-type (WT), GTKO, and GTKO/NeuGcKO pigs were used for the study. Human tissues and cultured cells were negative controls. Immunofluorescence staining was performed using anti-Gal and anti-NeuGc antibodies, and human IgM and IgG binding to tissues was determined. Flow cytometric analysis was used to determine Gal and NeuGc expression on cultured CECs and AECs and to measure human IgM/IgG binding to these cells. RESULTS Both Gal and NeuGc were detected on WT pig corneas and aortas. Although GTKO pigs expressed NeuGc, neither humans nor GTKO/NeuGcKO pigs expressed Gal or NeuGc. Human IgM/IgG binding to corneas and aortas from GTKO and GTKO/NeuGcKO pigs was reduced compared with binding to WT pigs. Human antibody binding to GTKO/NeuGcKO AECs was significantly less than that to GTKO AECs, but there was no significant difference in binding between GTKO and GTKO/NeuGcKO CECs. CONCLUSIONS The absence of NeuGc on GTKO aortic tissue and AECs is associated with reduced human antibody binding, and possibly will provide a better outcome in clinical xenotransplantation using vascularized organs. For clinical corneal xenotransplantation, the absence of NeuGc expression on GTKO/NeuGcKO pig corneas may not prove an advantage over GTKO corneas.
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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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Lee W, Hara H, Ezzelarab MB, Iwase H, Bottino R, Long C, Ramsoondar J, Ayares D, Cooper DKC. Initial in vitro studies on tissues and cells from GTKO/CD46/NeuGcKO pigs. Xenotransplantation 2016; 23:137-50. [PMID: 26988899 DOI: 10.1111/xen.12229] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/15/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND The impact that the absence of expression of NeuGc in pigs might have on pig organ or cell transplantation in humans has been studied in vitro, but only using red blood cells (pRBCs) and peripheral blood mononuclear cells (pPBMCs) as the target cells for immune assays. We have extended this work in various in vitro models and now report our initial results. METHODS The models we have used involve GTKO/hCD46 and GTKO/hCD46/NeuGcKO pig aortas and corneas, and pRBCs, pPBMCs, aortic endothelial cells (pAECs), corneal endothelial cells (pCECs), and isolated pancreatic islets. We have investigated the effect of the absence of NeuGc expression on (i) human IgM and IgG binding, (ii) the T-cell proliferative response, (iii) human platelet aggregation, and (iv) in an in vitro assay of the instant blood-mediated inflammatory reaction (IBMIR) following exposure of pig islets to human blood/serum. RESULTS The lack of expression of NeuGc on some pig tissues (aortas, corneas) and cells (RBCs, PBMCs, AECs) significantly reduces the extent of human antibody binding. In contrast, the absence of NeuGc expression on some pig tissues (CECs, isolated islet cells) does not reduce human antibody binding, possibly due to their relatively low NeuGc expression level. The strength of the human T-cell proliferative response may also be marginally reduced, but is already weak to GTKO/hCD46 pAECs and islet cells. We also demonstrate that the absence of NeuGc expression on GTKO/hCD46 pAECs does not reduce human platelet aggregation, and nor does it significantly modify the IBMIR to pig islets. CONCLUSION The absence of NeuGc on some solid organs from GTKO/hCD46/NeuGcKO pigs should reduce the human antibody response after clinical transplantation when compared to GTKO/hCD46 pig organs. However, the clinical benefit of using certain tissue (e.g., cornea, islets) from GTKO/hCD46/NeuGcKO pigs is questionable.
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Affiliation(s)
- Whayoung Lee
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mohamed B Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hayato Iwase
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rita Bottino
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Pittsburgh, PA, USA
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | | | | | - David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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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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Bottino R, Trucco M. Use of genetically-engineered pig donors in islet transplantation. World J Transplant 2015; 5:243-250. [PMID: 26722651 PMCID: PMC4689934 DOI: 10.5500/wjt.v5.i4.243] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/23/2015] [Accepted: 11/25/2015] [Indexed: 02/05/2023] Open
Abstract
Type 1 diabetes (T1D) is an autoimmune disease wherein the pancreas does not produce enough insulin due to islet beta cell destruction. Despite improvements in delivering exogenous insulin to T1D patients, pancreas or islet transplantation remains the best way to regulate their glycaemia. Results from experimental islet transplantation have improved dramatically in the last 15 years, to the point where it can be comparable to pancreas transplantation, but without the accompanying morbidity associated with this procedure. As with other transplants, the limiting factor in islet allotransplantation is the relatively small number of organs made available by deceased human donors throughout the world. A strong case can be made for islet xenotransplantation to fill the gap between supply and demand; however, transplantation across species presents challenges that are unique to that setting. In the search for the most suitable animal for human xenotransplantation, the pig has many advantages that make it the likely animal of choice. Potentially one of the most beneficial advantages is the ability to genetically engineer porcine donors to be more compatible with human recipients. Several genetic manipulations have already proven useful in relation to hyperacute rejection and inflammation (instant blood mediated inflammatory reaction), with the potential of even further advancement in the near future.
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Cooper DKC, Bottino R. Recent advances in understanding xenotransplantation: implications for the clinic. Expert Rev Clin Immunol 2015; 11:1379-90. [PMID: 26548357 PMCID: PMC4879962 DOI: 10.1586/1744666x.2015.1083861] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The results of organ and cell allotransplantation continue to improve, but the field remains limited by a lack of deceased donor organs. Xenotransplantation, for example, between pig and human, offers unlimited organs and cells for clinical transplantation. The immune barriers include a strong innate immune response in addition to the adaptive T-cell response. The innate response has largely been overcome by the transplantation of organs from pigs with genetic modifications that protect their tissues from this response. T-cell-mediated rejection can be controlled by immunosuppressive agents that inhibit costimulation. Coagulation dysfunction between the pig and primate remains problematic but is being overcome by the transplantation of organs from pigs that express human coagulation-regulatory proteins. The remaining barriers will be resolved by the introduction of novel genetically-engineered pigs. Limited clinical trials of pig islet and corneal transplantation are already underway.
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Affiliation(s)
- David K. C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Rita Bottino
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Pittsburgh, PA
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Manji RA, Lee W, Cooper DKC. Xenograft bioprosthetic heart valves: Past, present and future. Int J Surg 2015; 23:280-284. [PMID: 26190838 DOI: 10.1016/j.ijsu.2015.07.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 07/03/2015] [Indexed: 12/30/2022]
Abstract
The transplantation (implantation) of xenograft heart valves into humans has been carried out for >50 years. There has been considerable research into making this form of xenotransplantation successful, though it is not perfect yet. We review the understanding of the immune response to xenograft heart valves. Important steps in the history include understanding (i) the importance of glutaraldehyde in decreasing the immune response and (ii) the relationship between calcification (which is the main problem leading to xenograft failure) and the immune response. We subsequently discuss the importance of identifying xenoantigens that are important in leading to xenograft valve failure, and the potential of genetically-engineered pigs to allow the development of the 'ideal' heart valve for clinical valve replacement.
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Affiliation(s)
- Rizwan A Manji
- Department of Surgery, University of Manitoba, Winnipeg, Manitoba, Canada; Cardiac Sciences Program, Winnipeg Regional Health Authority and St. Boniface Hospital, Winnipeg, Manitoba, Canada.
| | - Whayoung Lee
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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Salama A, Evanno G, Harb J, Soulillou JP. Potential deleterious role of anti-Neu5Gc antibodies in xenotransplantation. Xenotransplantation 2014; 22:85-94. [PMID: 25308416 DOI: 10.1111/xen.12142] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 08/26/2014] [Indexed: 12/11/2022]
Abstract
Human beings do not synthesize the glycolyl form of the sialic acid (Neu5Gc) and only express the acetylated form of the sugar, whereas a diet-based intake of Neu5Gc provokes a natural immunization and production of anti-Neu5Gc antibodies in human serum. However, Neu5Gc is expressed on mammal glycoproteins and glycolipids in most organs and cells. We review here the relevance of Neu5Gc and anti-Neu5Gc antibodies in the context of xenotransplantation and the use of animal-derived molecules and products, as well as the possible consequences of a long-term exposure to anti-Neu5Gc antibodies in recipients of xenografts. In addition, the importance of an accurate estimation of the anti-Neu5Gc response following xenotransplantation and the future contribution of knockout animals mimicking the human situation are also assessed.
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Affiliation(s)
- Apolline Salama
- INSERM UMR1064, Centre for Research in Transplantation and Immunology-ITUN, Université de Nantes, Centre Hospitalier Universitaire Hôtel-Dieu, Nantes, France; Société d'Accélération du Transfert de Technologies Ouest Valorisation, Rennes Cedex, France
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Abstract
PURPOSE The aim of this study was to investigate the distribution of antigens other than galactose-α-1,3-galactose (Gal) (non-Gal) recognized by human and rhesus monkey serum antibodies in the α-1,3-galactosyltransferase gene-knockout (GTKO) pig cornea. METHODS The distribution of non-Gal, specifically N-glycolylneuraminic acid (NeuGc), in the corneas from wild-type (WT) and GTKO pigs was identified. Corneal sections from WT and GTKO pigs were incubated with human or rhesus monkey serum to determine immunoglobulin (Ig)M and IgG binding to corneal tissue by means of fluorescent microscopy. RESULTS Strong expression of NeuGc was found in all layers of both WT and GTKO pig corneas. In both humans and monkeys, antibody binding (IgG > IgM) to GTKO was found to be weaker than that to entire WT pig corneas, but in both, most antibody binding, especially IgG, was to the epithelium. There was weak diffuse antibody binding, especially of IgG, to the corneal stroma, suggesting binding to antigens expressed on collagen. There was no or minimal binding of IgM/IgG to the corneal endothelium. CONCLUSIONS Although the cornea is avascular, antibodies in primate serum can bind to pig antigens, especially on epithelial cells and stromal collagen. Although the binding to entire GTKO corneas was weaker than that to WT corneas, deletion of the expression of NeuGc and expression of human complement-regulatory proteins in the pig cornea will be important if prolonged clinical corneal xenograft survival is to be achieved.
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Iwase H, Ezzelarab MB, Ekser B, Cooper DKC. The role of platelets in coagulation dysfunction in xenotransplantation, and therapeutic options. Xenotransplantation 2014; 21:201-20. [PMID: 24571124 DOI: 10.1111/xen.12085] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 01/08/2014] [Indexed: 12/11/2022]
Abstract
Xenotransplantation could resolve the increasing discrepancy between the availability of deceased human donor organs and the demand for transplantation. Most advances in this field have resulted from the introduction of genetically engineered pigs, e.g., α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for one or more human complement-regulatory proteins (e.g., CD55, CD46, CD59). Failure of these grafts has not been associated with the classical features of acute humoral xenograft rejection, but with the development of thrombotic microangiopathy in the graft and/or consumptive coagulopathy in the recipient. Although the precise mechanisms of coagulation dysregulation remain unclear, molecular incompatibilities between primate coagulation factors and pig natural anticoagulants exacerbate the thrombotic state within the xenograft vasculature. Platelets play a crucial role in thrombosis and contribute to the coagulation disorder in xenotransplantation. They are therefore important targets if this barrier is to be overcome. Further genetic manipulation of the organ-source pigs, such as pigs that express one or more coagulation-regulatory genes (e.g., thrombomodulin, endothelial protein C receptor, tissue factor pathway inhibitor, CD39), is anticipated to inhibit platelet activation and the generation of thrombus. In addition, adjunctive pharmacologic anti-platelet therapy may be required. The genetic manipulations that are currently being tested are reviewed, as are the potential pharmacologic agents that may prove beneficial.
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Affiliation(s)
- Hayato Iwase
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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Byrne GW, Azimzadeh AM, Ezzelarab M, Tazelaar HD, Ekser B, Pierson RN, Robson SC, Cooper DKC, McGregor CGA. Histopathologic insights into the mechanism of anti-non-Gal antibody-mediated pig cardiac xenograft rejection. Xenotransplantation 2013; 20:292-307. [PMID: 25098626 PMCID: PMC4126170 DOI: 10.1111/xen.12050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 07/31/2013] [Indexed: 01/13/2023]
Abstract
The histopathology of cardiac xenograft rejection has evolved over the last 20 yr with the development of new modalities for limiting antibody-mediated injury, advancing regimens for immune suppression, and an ever-widening variety of new donor genetics. These new technologies have helped us progress from what was once an overwhelming anti-Gal-mediated hyperacute rejection to a more protracted anti-Gal-mediated vascular rejection to what is now a more complex manifestation of non-Gal humoral rejection and coagulation dysregulation. This review summarizes the changing histopathology of Gal- and non-Gal-mediated cardiac xenograft rejection and discusses the contributions of immune-mediated injury, species-specific immune-independent factors, transplant and therapeutic procedures, and donor genetics to the overall mechanism(s) of cardiac xenograft rejection.
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Affiliation(s)
- Guerard W Byrne
- Institute of Cardiovascular Science, University College London, London, UK; Department of Surgery, Mayo Clinic, Rochester, MN, USA
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Meisen I, Rosenbrück R, Galla HJ, Hüwel S, Kouzel IU, Mormann M, Karch H, Müthing J. Expression of Shiga toxin 2e glycosphingolipid receptors of primary porcine brain endothelial cells and toxin-mediated breakdown of the blood-brain barrier. Glycobiology 2013; 23:745-59. [PMID: 23431059 DOI: 10.1093/glycob/cwt013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Shiga toxin (Stx) 2e, released by certain Stx-producing Escherichia coli, is presently the best characterized virulence factor responsible for pig edema disease, which is characterized by hemorrhagic lesions, neurological disorders and often fatal outcomes. Although Stx2e-mediated brain vascular injury is the key event in development of neurologic signs, the glycosphingolipid (GSL) receptors of Stx2e and toxin-mediated impairment of pig brain endothelial cells have not been investigated so far. Here, we report on the detailed structural characterization of Stx2e receptors globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer), which make up the major neutral GSLs in primary porcine brain capillary endothelial cells (PBCECs). Various Gb3Cer and Gb4Cer lipoforms harboring sphingenine (d18:1) or sphinganine (d18:0) and mostly a long-chain fatty acid (C20-C24) were detected. A notable batch-to-batch heterogeneity of primary endothelial cells was observed regarding the extent of ceramide hydroxylation of Gb3Cer or Gb4Cer species. Gb3Cer, Gb4Cer and sphingomyelin preferentially distribute to detergent-resistant membrane fractions and can be considered lipid raft markers in PBCECs. Moreover, we employed an in vitro model of the blood-brain barrier (BBB), which exhibited strong cytotoxic effects of Stx2e on the endothelial monolayer and a rapid collapse of the BBB. These data strongly suggest the involvement of Stx2e in cerebral vascular damage with resultant neurological disturbance characteristic of edema disease.
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Affiliation(s)
- Iris Meisen
- Institute for Hygiene, Robert-Koch-Str. 41, Germany
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Müthing J, Meisen I, Zhang W, Bielaszewska M, Mormann M, Bauerfeind R, Schmidt MA, Friedrich AW, Karch H. Promiscuous Shiga toxin 2e and its intimate relationship to Forssman. Glycobiology 2012; 22:849-62. [DOI: 10.1093/glycob/cws009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Breimer ME. Gal/non-Gal antigens in pig tissues and human non-Gal antibodies in the GalT-KO era. Xenotransplantation 2012; 18:215-28. [PMID: 21848538 DOI: 10.1111/j.1399-3089.2011.00644.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Our knowledge regarding Gal and non-Gal antigens in GalT-KO pig tissues can be summarized as α3Galactosyl-tranferase gene knock out eliminates the Galα3Galβ4GlcNAc-R antigen expression in pig tissues as well as anti-Gal antibody binding. Other Galα-terminating saccharides (e.g. iGb3 glycolipids and Galα2 determinants) may be present but have not been documented. α3Galactosyl-tranferase gene knock out slightly changes the carbohydrate antigen expression but no "new" antigens recognized by the human immune system have been found. Non-Gal antigens are both of protein and carbohydrate nature but their exact chemical structures are poorly defined. Regarding human non-Gal antibodies our knowledge is as Non-Gal antibodies exist naturally and increase in humans/non-human primate (NHP) receiving WT or GalT-KO pig grafts. Non-Gal antibodies with new antigen epitope recognition can be induced in humans/NHP after challenge by WT or GalT-KO pig grafts. Non-Gal antibodies react with both carbohydrates and proteins. Part of the protein reactivity is directed to glycoprotein carbohydrates chains. Non-Gal antibodies reacting with neuraminic acid terminated saccharides (both N-Acetyl and N-Glycoloyl variants) are present in humans/NHP. Anti-neuraminic acid antibodies are increased, as well as induced, after grafting pig organs into humans/NHP. Non-Gal antibodies does not cause hyperacute xenorejection but can be cytotoxic and cause xenoorgan damage. If humans sensitized to HLA antigens are at a higher risk of rejecting pig xenograft compared with non-sensitized individuals is not fully clarified. Clinical trials are needed to evaluate the relevance of non-Gal antigens/antibodies and for the xenofield to advance.
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Affiliation(s)
- Michael E Breimer
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
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Abstract
Although corneal transplantation (Tx) is readily available in the United States and certain other regions of the developed world, the need for human donor corneas worldwide far exceeds supply. There is currently renewed interest in the possibility of using corneas from other species, especially pigs, for Tx into humans (xeno-Tx). The biomechanical properties of human and pig corneas are similar. Studies in animal models of corneal xeno-Tx have documented both humoral and cellular immune responses that play roles in xenograft rejection. The results obtained from the Tx of corneas from wild-type (ie, genetically unmodified) pigs into nonhuman primates have been surprisingly good and encouraging. Recent progress in the genetic manipulation of pigs has led to the prospect that the remaining immunological barriers will be overcome. There is every reason for optimism that corneal xeno-Tx will become a clinical reality within the next few years.
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