101
|
Adams AB, Kim SC, Martens GR, Ladowski JM, Estrada JL, Reyes LM, Breeden C, Stephenson A, Eckhoff DE, Tector M, Tector AJ. Xenoantigen Deletion and Chemical Immunosuppression Can Prolong Renal Xenograft Survival. Ann Surg 2018; 268:564-573. [PMID: 30048323 PMCID: PMC6382078 DOI: 10.1097/sla.0000000000002977] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Xenotransplantation using pig organs could end the donor organ shortage for transplantation, but humans have xenoreactive antibodies that cause early graft rejection. Genome editing can eliminate xenoantigens in donor pigs to minimize the impact of these xenoantibodies. Here we determine whether an improved cross-match and chemical immunosuppression could result in prolonged kidney xenograft survival in a pig-to-rhesus preclinical model. METHODS Double xenoantigen (Gal and Sda) knockout (DKO) pigs were created using CRISPR/Cas. Serum from rhesus monkeys (n = 43) was cross-matched with cells from the DKO pigs. Kidneys from the DKO pigs were transplanted into rhesus monkeys (n = 6) that had the least reactive cross-matches. The rhesus recipients were immunosuppressed with anti-CD4 and anti-CD8 T-cell depletion, anti-CD154, mycophenolic acid, and steroids. RESULTS Rhesus antibody binding to DKO cells is reduced, but all still have positive CDC and flow cross-match. Three grafts were rejected early at 5, 6, and 6 days. Longer survival was achieved in recipients with survival to 35, 100, and 435 days. Each of the 3 early graft losses was secondary to IgM antibody-mediated rejection. The 435-day graft loss occurred secondary to IgG antibody-mediated rejection. CONCLUSIONS Reducing xenoantigens in donor pigs and chemical immunosuppression can be used to achieve prolonged renal xenograft survival in a preclinical model, suggesting that if a negative cross-match can be obtained for humans then prolonged survival could be achieved.
Collapse
Affiliation(s)
| | | | | | | | | | - Luz M Reyes
- University of Alabama Birmingham, Birmingham, AL
| | | | | | | | - Matt Tector
- University of Alabama Birmingham, Birmingham, AL
| | | |
Collapse
|
102
|
Iwase H, Klein EC, Cooper DK. Physiologic Aspects of Pig Kidney Transplantation in Nonhuman Primates. Comp Med 2018; 68:332-340. [PMID: 30208986 DOI: 10.30802/aalas-cm-17-000117] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Xenotransplantation can provide a solution to the current shortage of human organs for patients with terminal renal failure. The increasing availability of genetically engineered pigs, effective immunosuppressive therapy, and antiinflammatory therapy help to protect pig tissues from the primate immune response and can correct molecular incompatibilities. Life-supporting pig kidney xenografts have survived in NHP for more than 6 mo in the absence of markers of consumptive coagulopathy. However, few reports have focused on the physiologic aspects of life-supporting pig kidney xenografts. We have reviewed the literature regarding pig kidney xenotransplantation in NHP. The available data indicate (1) normal serum creatinine, (2) normal serum electrolytes, except for a trend toward increased calcium levels and a transient rise in phosphate followed by a fall to slightly subnormal values, (3) minimal or modest proteinuria without hypoalbuminemia (suggesting that previous reports of proteinuria likely were due to a low-grade immune response rather than physiologic incompatibilities), (4) possible discrepancies between pig erythropoietin and the primate erythropoietin receptor, and (5) significant early increase in kidney graft size, which might result from persistent effects of pig growth hormone. Further study is required regarding identification and investigation of physiologic incompatibilities. However, current evidence suggests that, in the absence of an immune response, a transplanted pig kidney likely would satisfactorily support a human patient.
Collapse
Affiliation(s)
- Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham Alabama, USA.
| | - Edwin C Klein
- Department of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - David Kc Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham Alabama, USA
| |
Collapse
|
103
|
Lee SJ, Kim JS, Chee HK, Yun IJ, Park KS, Yang HS, Park JH. Seven Years of Experiences of Preclinical Experiments of Xeno-Heart Transplantation of Pig to Non-Human Primate (Cynomolgus Monkey). Transplant Proc 2018; 50:1167-1171. [PMID: 29731087 DOI: 10.1016/j.transproceed.2018.01.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 01/22/2018] [Indexed: 11/20/2022]
Abstract
BACKGROUND The absolute shortage of donors compared with patients requiring transplantation is currently an unsolved problem, and the only possible solution may be xenotransplantation. To establish a successful clinical trial, a preclinical study using nonhuman primates is essential. Starting in November 2011, our team initiated heterotopic abdominal heart xenotransplantation, the first in the Republic of Korea. We present here the initial 7-year results. METHODS A total of 22 xenotransplantation procedures have been performed since 2011. Single transgenic pig (alpha-galactosidase transferase knockout [GalT KO], n = 16), double transgenic pig (GalT KO + CD46, n = 3, and GalT KO + CD39, n = 2), and triple transgenic pig (GalT KO + CD46 + CD70, n = 1) models were used. Our baseline regimen of immunosuppressants comprised CD154 ab, rituximab, anti-thymocyte globulin, tacrolimus, mycophenolate mofetil, and steroids. RESULTS The mean graft survival was 16 ± 16.27 days, and the mean graft survival was significantly longer in cases performed since 2014 (7.5 ± 8.03 days vs 24.67 ± 17.50; P = .01). Although the donor heart ischemic time was decreased per annum, no correlations could be found between ischemic time and survival days of the graft. Double or triple genetic manipulated hearts exhibited significantly better survival (11.63 ± 11.29 days vs 30.83 ± 20.34 days; P = .03). When the ratio of heart weight (grams) to nonhuman primate weight (kilograms) was lower, the results tended to be better (P < .05). The rate of immediate postoperative bleeding (9%, n = 2) causing death was relatively high in the earlier period, but there have been no serious surgical complications affecting graft survival since 2013. CONCLUSIONS Investigation of effective and optimal target genes for each organ to further progression toward better results is important. In addition, the immunosuppressive regimen needs to be further studied and constantly refined.
Collapse
Affiliation(s)
- S J Lee
- Department of Thoracic and Cardiovascular Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - J S Kim
- Department of Thoracic and Cardiovascular Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - H K Chee
- Department of Thoracic and Cardiovascular Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
| | - I J Yun
- Department of Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - K S Park
- Department of Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - H S Yang
- Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - J H Park
- Department of Nephrology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| |
Collapse
|
104
|
Abstract
The growing shortage of available organs is a major problem in transplantology. Thus, new and alternative sources of organs need to be found. One promising solution could be xenotransplantation, i.e., the use of animal cells, tissues and organs. The domestic pig is the optimum donor for such transplants. However, xenogeneic transplantation from pigs to humans involves high immune incompatibility and a complex rejection process. The rapid development of genetic engineering techniques enables genome modifications in pigs that reduce the cross-species immune barrier.
Collapse
|
105
|
Wang L, Cooper DKC, Burdorf L, Wang Y, Iwase H. Overcoming Coagulation Dysregulation in Pig Solid Organ Transplantation in Nonhuman Primates: Recent Progress. Transplantation 2018; 102:1050-1058. [PMID: 29538262 PMCID: PMC7228622 DOI: 10.1097/tp.0000000000002171] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/22/2018] [Accepted: 01/26/2018] [Indexed: 01/17/2023]
Abstract
There has recently been considerable progress in the results of pig organ transplantation in nonhuman primates, largely associated with the availability of (i) pigs genetically engineered to overcome coagulation dysregulation, and (ii) novel immunosuppressive agents. The barriers of thrombotic microangiopathy and/or consumptive coagulation were believed to be associated with (i) activation of the graft vascular endothelial cells by a low level of antipig antibody binding and/or complement deposition and/or innate immune cell activity, and (ii) molecular incompatibilities between the nonhuman primate and pig coagulation-anticoagulation systems. The introduction of a human coagulation-regulatory transgene, for example, thrombomodulin, endothelial protein C receptor, into the pig vascular endothelial cells has contributed to preventing a procoagulant state from developing, resulting in a considerable increase in graft survival. In the heterotopic (non-life-supporting) heart transplant model, graft survival has increased from a maximum of 179 days in 2005 to 945 days. After life-supporting kidney transplantation, survival has been extended from 90 days in 2004 to 499 days. In view of the more complex coagulation dysfunction seen after pig liver and, particularly, lung transplantation, progress has been less dramatic, but the maximum survival of a pig liver has been increased from 7 days in 2010 to 29 days, and of a pig lung from 4 days in 2007 to 9 days. There is a realistic prospect that the transplantation of a kidney or heart, in combination with a conventional immunosuppressive regimen, will enable long-term recipient survival.
Collapse
Affiliation(s)
- Liaoran Wang
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham AL
- Second Affiliated Hospital, University of South China, Hengyang City, Hunan, China
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham AL
| | - Lars Burdorf
- Division of Cardiac Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD
| | - Yi Wang
- Second Affiliated Hospital, University of South China, Hengyang City, Hunan, China
| | - Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham AL
| |
Collapse
|
106
|
Abstract
CRISPR is a nuclease guidance system that enables rapid and efficient gene editing of specific DNA sequences within genomes. We review applications of CRISPR for the study and treatment of kidney disease. CRISPR enables functional experiments in cell lines and model organisms to validate candidate genes arising from genetic studies. CRISPR has furthermore been used to establish the first models of genetic disease in human kidney organoids derived from pluripotent stem cells. These gene-edited organoids are providing new insight into the cellular mechanisms of polycystic kidney disease and nephrotic syndrome. CRISPR-engineered cell therapies are currently in clinical trials for cancers and immunologic syndromes, an approach that may be applicable to inflammatory conditions such as lupus nephritis. Use of CRISPR in large domestic species such as pigs raises the possibility of farming kidneys for transplantation to alleviate the shortage of donor organs. However, significant challenges remain, including how to effectively deliver CRISPR to kidneys and how to control gene editing events within the genome. Thorough testing of CRISPR in preclinical models will be critical to the safe and efficacious translation of this powerful young technology into therapies.
Collapse
Affiliation(s)
- Nelly M Cruz
- Division of Nephrology, University of Washington School of Medicine, Seattle WA; Kidney Research Institute, University of Washington School of Medicine, Seattle WA; Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle WA; Department of Medicine, University of Washington School of Medicine, Seattle WA
| | - Benjamin S Freedman
- Division of Nephrology, University of Washington School of Medicine, Seattle WA; Kidney Research Institute, University of Washington School of Medicine, Seattle WA; Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle WA; Department of Medicine, University of Washington School of Medicine, Seattle WA.
| |
Collapse
|
107
|
Denner J. Why was PERV not transmitted during preclinical and clinical xenotransplantation trials and after inoculation of animals? Retrovirology 2018; 15:28. [PMID: 29609635 PMCID: PMC5879552 DOI: 10.1186/s12977-018-0411-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/22/2018] [Indexed: 01/27/2023] Open
Abstract
Porcine endogenous retroviruses (PERVs) are present in the genome of all pigs, they infect certain human cells and therefore pose a special risk for xenotransplantation using pig cells, tissues and organs. Xenotransplantation is being developed in order to alleviate the reduced availability of human organs. Despite the fact that PERVs are able to infect certain human cells and cells from other species, transmission of PERVs has not been observed when animals (including non-human primates) were inoculated with PERV preparations or during preclinical xenotransplantations. The data indicate that PERVs were not transmitted because they were not released from the transplant or were inhibited by intracellular restriction factors and innate immunity in the recipient. In a single study in guinea pigs, a transient PERV infection and anti-PERV antibodies were described, indicating that in this case at least, the immune system may also have been involved.
Collapse
Affiliation(s)
- Joachim Denner
- Robert Koch Institute, Nordufer 20, 13353, Berlin, Germany.
| |
Collapse
|
108
|
Abstract
PURPOSE OF REVIEW This review describes recent progress in tolerance-inducing strategies across xenogeneic immunological barriers as well as the potential benefit of a tolerance strategy for islets and kidney xenotransplantation. RECENT FINDINGS Using advanced gene editing technologies, xenotransplantation from multitransgenic alpha-1,3-galactosyltransferase knockout pigs has demonstrated marked prolongation of renal xenograft survival, ranging from days to greater than several months for life-supporting kidneys, and more than 2 years in a heterotopic nonlife-supporting cardiac xenograft model. Continuous administration of multiple immunosuppressive drugs has been required and attempts to taper immunosuppression have been unsuccessful. It appears likely that low levels of T cell dependent antibodies and activation of innate responses are responsible for xenograft loss. Mixed chimerism and thymic transplantation approaches have achieved xenogeneic tolerance in pig-to-mouse models and both have recently been extended to pig-to-baboon models. Encouraging results have been reported, including persistence of macrochimerism, prolonged pig skin graft survival, donor-specific unresponsiveness in vitro and detection of recent T cell emigrants in vivo. SUMMARY Although tolerance induction in vivo has not yet been achieved in pig-to-baboon models, recent results are encouraging that this goal will be attainable through genetic engineering of porcine donors.
Collapse
|
109
|
Abstract
PURPOSE OF REVIEW This review describes the most recent progress in xeno lung transplantation (XLTx) to date. It describes the potential mechanisms of early xeno lung graft loss, as well as the latest therapeutic strategies to overcome them. RECENT FINDINGS Using ex-vivo perfusion models of porcine lungs with human blood, the use of genetically modified pig lungs along with novel pharmaceutical approaches has recently been studied. Strategies that have demonstrated improved lung survival include the knockout of known xenoantigens (GalTKO and N-glycolylneuraminic acid-KO), genes that regulate complement activation (hCD46 and hCD55), as well as the inflammation/coagulation cascade (human leukocyte antigen-E, human thrombomodulin, human endothelial protein C receptor, hCD47, hCD39, hCD73 and heme oxygenase-1). Furthermore, pharmacologic interventions including the depletion of pulmonary intravascular macrophages or von Willebrand factor, inhibition of thromboxane synthase and blockade of histamine receptors have also demonstrated protective effects on xeno lung grafts. Using in-vivo pig to nonhuman primate lung transplant models, these approaches have been shown to extend pulmonary xenograft survival to 5 days. SUMMARY The development of new multitransgenic GalTKO pigs has demonstrated prolongation of porcine xenograft survival; however, advancement in XLTx has remained frustratingly limited. Further intensive and innovative strategies including genetic manipulation of donors, as well as inflammation/coagulation dysregulation, are required to make XLTx a clinical possibility.
Collapse
|
110
|
Abstract
PURPOSE OF REVIEW To review the progress in the field of xenotransplantation with special attention to most recent encouraging findings which will eventually bring xenotransplantation to the clinic in the near future. RECENT FINDINGS Starting from early 2000, with the introduction of galactose-α1,3-galactose (Gal)-knockout pigs, prolonged survival especially in heart and kidney xenotransplantation was recorded. However, remaining antibody barriers to non-Gal antigens continue to be the hurdle to overcome. The production of genetically engineered pigs was difficult requiring prolonged time. However, advances in gene editing, such as zinc finger nucleases, transcription activator-like effector nucleases, and most recently clustered regularly interspaced short palindromic repeats (CRISPR) technology made the production of genetically engineered pigs easier and available to more researchers. Today, the survival of pig-to-nonhuman primate heterotopic heart, kidney, and islet xenotransplantation reached more than 900, more than 400, and more than 600 days, respectively. The availability of multiple-gene pigs (five or six genetic modifications) and/or newer costimulation blockade agents significantly contributed to this success. Now, the field is getting ready for clinical trials with an international consensus. SUMMARY Clinical trials in cellular or solid organ xenotransplantation are getting closer with convincing preclinical data from many centers. The next decade will show us new achievements and additional barriers in clinical xenotransplantation.
Collapse
|
111
|
Remaining Physiological Barriers in Porcine Kidney Xenotransplantation: Potential Pathways behind Proteinuria as well as Factors Related to Growth Discrepancies following Pig-to-Kidney Xenotransplantation. J Immunol Res 2018; 2018:6413012. [PMID: 29687010 PMCID: PMC5857301 DOI: 10.1155/2018/6413012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 11/29/2017] [Accepted: 01/18/2018] [Indexed: 12/13/2022] Open
Abstract
Considerable shortages in the supply of available organs continue to plague the field of solid organ transplantation. Despite changes in allocation, as well as the utilization of extended criteria and living donors, the number of patients waiting for organs continues to grow at an alarming pace. Xenotransplantation, cross-species solid organ transplantation, offers one potential solution to this dilemma. Previous extensive research dedicated to this field has allowed for resolution of xenograft failure due to acute rejection, leaving new areas of unresolved challenges as barriers to success in large animal models. Specific to kidney xenotransplantation, recent data seems to indicate that graft compromise can occur due to discrepancies in growth between breeds of donors and significant proteinuria leading to nephrotic syndrome in the recipient. Given these potential limitations, herein, we review potential pathways behind proteinuria, as well as potential causative factors related to growth discrepancies. Control of both of these has the potential to allow xenotransplantation to become clinically applicable in an effort to resolve this organ shortage crisis.
Collapse
|
112
|
Cooper DKC, Iwase H, Wang L, Yamamoto T, Li Q, Li J, Zhou H, Hara H. Bringing Home The Bacon: Update on The State of Kidney Xenotransplantation. Blood Purif 2018; 45:254-259. [PMID: 29478054 DOI: 10.1159/000485163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND There is a continuing critical shortage of organs from deceased human donors for transplantation, particularly for patients awaiting kidney transplantation. Efforts are being made to resolve the donor kidney shortage by the transplantation of kidneys from genetically-engineered pigs. SUMMARY This review outlines the pathobiological barriers to pig organ xenotransplantation in primates, which include (i) antibody-dependent complement-mediated rejection, (ii) a T cell-mediated elicited antibody and cellular response, (iii) coagulation dysregulation between pigs and primates, and (iv) a persistent inflammatory response. As a result of increasing genetic manipulation of the pig and the introduction of novel immunosuppressive agents, pig kidney graft survival has increased from minutes to months, and even to >1 year in some cases. Aspects of the selection of the patients for a first clinical trial are discussed. Although there would appear to be some cross-reactivity between anti-human leukocyte antigen (HLA) antibodies and swine leukocyte antigens expressed in pigs, some HLA-sensitized patients will be at no disadvantage if they receive a pig kidney. Furthermore, the current limited evidence is that, even if the patient becomes sensitized to pig antigens (after a pig organ transplant), this would not be detrimental to a subsequent allotransplant. The potential risk of infection with a pig microorganism, and the function of a pig kidney in a primate are also discussed. Key Message: The recent encouraging results of pig kidney transplantation in nonhuman primates suggest the likelihood of a successful (and safe) initial clinical trial, with graft survival for months or possibly years.
Collapse
Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - H Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - L Wang
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Second Affiliated Hospital, University of South China, Hengyang, China
| | - T Yamamoto
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Qi Li
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Second Affiliated Hospital, University of South China, Hengyang, China
| | - J Li
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Second Affiliated Hospital, University of South China, Hengyang, China
| | - H Zhou
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Huazhong University of Science and Technology, Tongji Hospital, Wuhan, China
| | - H Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
113
|
Denner J, Reichart B, Längin M. Does size matter? Xenotransplantation 2018; 25:e12383. [DOI: 10.1111/xen.12383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/08/2017] [Accepted: 01/02/2018] [Indexed: 01/05/2023]
Affiliation(s)
| | - Bruno Reichart
- Walter Brendel Centre of Experimental Medicine; Ludwig-Maximilians-Universität München (LMU); Munich Germany
| | - Matthias Längin
- Department of Anaesthesiology; University Hospital; LMU; Munich Germany
| |
Collapse
|
114
|
Meier RPH, Muller YD, Balaphas A, Morel P, Pascual M, Seebach JD, Buhler LH. Xenotransplantation: back to the future? Transpl Int 2018; 31:465-477. [PMID: 29210109 DOI: 10.1111/tri.13104] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/05/2017] [Accepted: 11/26/2017] [Indexed: 12/26/2022]
Abstract
The field of xenotransplantation has fluctuated between great optimism and doubts over the last 50 years. The initial clinical attempts were extremely ambitious but faced technical and ethical issues that prompted the research community to go back to preclinical studies. Important players left the field due to perceived xenozoonotic risks and the lack of progress in pig-to-nonhuman-primate transplant models. Initial apparently unsurmountable issues appear now to be possible to overcome due to progress of genetic engineering, allowing the generation of multiple-xenoantigen knockout pigs that express human transgenes and the genomewide inactivation of porcine endogenous retroviruses. These important steps forward were made possible by new genome editing technologies, such as CRISPR/Cas9, allowing researchers to precisely remove or insert genes anywhere in the genome. An additional emerging perspective is the possibility of growing humanized organs in pigs using blastocyst complementation. This article summarizes the current advances in xenotransplantation research in nonhuman primates, and it describes the newly developed genome editing technology tools and interspecific organ generation.
Collapse
Affiliation(s)
- Raphael P H Meier
- Visceral and Transplant Surgery, University Hospitals of Geneva, Geneva, Switzerland
| | - Yannick D Muller
- Division of Clinical Immunology and Allergy, Department of Medical Specialties, University Hospitals and Medical Faculty, Geneva, Switzerland.,Transplantation Center, Lausanne University Hospital, Lausanne, Switzerland
| | - Alexandre Balaphas
- Visceral and Transplant Surgery, University Hospitals of Geneva, Geneva, Switzerland
| | - Philippe Morel
- Visceral and Transplant Surgery, University Hospitals of Geneva, Geneva, Switzerland
| | - Manuel Pascual
- Transplantation Center, Lausanne University Hospital, Lausanne, Switzerland
| | - Jörg D Seebach
- Division of Clinical Immunology and Allergy, Department of Medical Specialties, University Hospitals and Medical Faculty, Geneva, Switzerland
| | - Leo H Buhler
- Visceral and Transplant Surgery, University Hospitals of Geneva, Geneva, Switzerland
| |
Collapse
|
115
|
Shin JS, Kim JM, Min BH, Yoon IH, Kim HJ, Kim JS, Kim YH, Kang SJ, Kim J, Kang HJ, Lim DG, Hwang ES, Ha J, Kim SJ, Park WB, Park CG. Pre-clinical results in pig-to-non-human primate islet xenotransplantation using anti-CD40 antibody (2C10R4)-based immunosuppression. Xenotransplantation 2018; 25:10.1111/xen.12356. [PMID: 29057561 PMCID: PMC5809197 DOI: 10.1111/xen.12356] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 08/16/2017] [Accepted: 09/01/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Islet transplantation is an effective therapy for selected patients with type 1 diabetes with labile glycemic control and hypoglycemic unawareness, but donor organs are limited. Islet xenotransplantation using porcine islets will potentially solve this problem. Although successful proof of concept studies using clinically inapplicable anti-CD154 monoclonal antibody (mAb) in pig-to-non-human primate (NHP) islet xenotransplantation has been demonstrated by several groups worldwide, potentially clinically applicable anti-CD40 (2C10R4) mAb-based studies have not been reported. METHODS Nine streptozotocin (STZ)-induced diabetic rhesus monkeys were transplanted with adult porcine islets isolated from designated pathogen-free (DPF) miniature pigs. They were treated with anti-CD40 mAb-based immunosuppressive regimen and were divided into 3 groups: anti-CD40 only group (n = 2), belatacept group (anti-CD40 mAb+belatacept, n = 2), and tacrolimus group (anti-CD40 mAb+tacrolimus, n = 5). All monkeys received anti-thymocyte globulin (ATG), cobra venom factor (CVF), adalimumab, and sirolimus. Blood glucose levels (BGL) and serum porcine C-peptide concentrations were measured. Humoral and cellular immune responses were assessed by ELISA and ELISPOT, respectively. Liver biopsy and subsequent immunohistochemistry were conducted. RESULTS All animals restored normoglycemia immediately after porcine islet transplantation and finished the follow-up without any severe adverse effects except for one animal (R092). Most animals maintained their body weight. Median survival, as defined by a serum porcine C-peptide concentration of >0.15 ng/mL, was 31, 27, and 60 days for anti-CD40 only, belatacept, and tacrolimus groups, respectively. Anti-αGal IgG levels in serum and the number of interferon-γ secreting T cells in peripheral blood mononuclear cells did not increase in most animals. CONCLUSION These results showed that anti-CD40 mAb combined with tacrolimus was effective in prolonging porcine islet graft survival, but anti-CD40 mAb was not as effective as anti-CD154 mAb in terms of preventing early islet loss.
Collapse
Affiliation(s)
- Jun-Seop Shin
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
- Institute of Endemic Diseases, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
| | - Jong-Min Kim
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Institute of Endemic Diseases, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
| | - Byoung-Hoon Min
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
| | - Il Hee Yoon
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
| | - Hyun Je Kim
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
- Department of Biomedical Sciences, Hallym University College of Medicine, Anyang, Korea
| | - Jung-Sik Kim
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
- Institute of Endemic Diseases, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
| | - Yong-Hee Kim
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
| | - Seong-Jun Kang
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
- Department of Biomedical Sciences, Hallym University College of Medicine, Anyang, Korea
| | - Jiyeon Kim
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
| | - Hee-Jung Kang
- Department of Laboratory Medicine, Hallym University College of Medicine, Anyang, Korea
| | | | - Eung-Soo Hwang
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
| | - Jongwon Ha
- Department of Surgery, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Sang-Joon Kim
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Myong-Ji Hospital, Koyang-si, Kyeonggi-do, Korea
| | - Wan Beom Park
- Department of Internal Medicine, Seoul National University Hospital, Seoul 136-799, Korea
| | - Chung-Gyu Park
- Xenotransplantation Research Center, Hallym University College of Medicine, Anyang, Korea
- Department of Microbiology and Immunology, Hallym University College of Medicine, Anyang, Korea
- Institute of Endemic Diseases, Hallym University College of Medicine, Anyang, Korea
- Cancer Research Institute, Hallym University College of Medicine, Anyang, Korea
- Department of Biomedical Sciences, Hallym University College of Medicine, Anyang, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul 136-799, Korea
| |
Collapse
|
116
|
Min BH, Shin JS, Kim JM, Kang SJ, Kim HJ, Yoon IH, Park SK, Choi JW, Lee MS, Park CG. Delayed revascularization of islets after transplantation by IL-6 blockade in pig to non-human primate islet xenotransplantation model. Xenotransplantation 2017; 25. [PMID: 29210476 DOI: 10.1111/xen.12374] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/12/2017] [Accepted: 11/10/2017] [Indexed: 01/16/2023]
Abstract
BACKGROUND Pancreatic islet transplantation is currently proven as a promising treatment for type 1 diabetes patients with labile glycemic control and severe hypoglycemia unawareness. Upon islet transplantation, revascularization is essential for proper functioning of the transplanted islets. As IL-6 is important for endothelial cell survival and systemic inflammation related to xenograft, the effect of IL-6 receptor antagonist, tocilizumab, on revascularization of the transplanted islets was examined in pig to non-human primate islet xenotransplantation model. Also, the endothelial cell origin in a new vessel of the transplanted pig islets was determined. METHODS Pig islets were isolated from designated pathogen-free (DPF) SNU miniature pigs and transplanted via portal vein into five streptozotocin-induced diabetic monkeys. One group (n = 2, basal group) was treated with anti-thymoglobulin (ATG), anti-CD40 antibody (2C10R4), sirolimus, and tacrolimus, and the other group was additionally given tocilizumab on top of basal immunosuppression (n = 3, Tocilizumab group). To confirm IL-6 blocking effect, C-reactive protein (CRP) levels and serum IL-6 concentration were measured. Scheduled biopsy of the margin of the posterior segment right lobe inferior of the liver was performed at 3 weeks after transplantation to assess the degree of revascularization of the transplanted islets. Immunohistochemical staining using anti-insulin, anti-CD31 antibodies, and lectin IB4 was conducted to find the origin of endothelial cells in the islet graft. RESULTS CRP significantly increased at 1~2 days after transplantation in Basal group, but not in Tocilizumab group, and higher serum IL-6 concentration was measured in latter group, showing the biological potency of tocilizumab. In Basal group, well-developed endothelial cells were observed on the peri- and intraislet area, whereas the number of CD31+ cells in the intraislet space was significantly reduced in Tocilizumab group. Finally, new endothelial cells in the pig islet graft were positive for CD31, but not for lectin IB4, suggesting that they are originated from the recipient monkey. CONCLUSIONS Our results demonstrated that tocilizumab can delay revascularization of the transplanted islet, although this effect had no significant correlation to the overall islet graft survival. In the pig to NHP islet xenotransplantation model, the endothelial cells from recipient monkey form new blood vessels in and around pig islets.
Collapse
Affiliation(s)
- Byoung-Hoon Min
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea.,Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.,Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul, Korea
| | - Jun-Seop Shin
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea.,Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.,Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul, Korea
| | - Jong-Min Kim
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea.,Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.,Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul, Korea
| | - Seong-Jun Kang
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea
| | - Hyun-Je Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea
| | - Il-Hee Yoon
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea.,Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea.,Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul, Korea
| | - Su-Kyoung Park
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Ji-Won Choi
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Min-Suk Lee
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Chung-Gyu Park
- Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea.,Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea.,Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Korea
| |
Collapse
|
117
|
Cooper DKC, Cowan P, Fishman JA, Hering BJ, Mohiuddin MM, Pierson RN, Sachs DH, Schuurman HJ, Dennis JU, Tönjes RR. Joint FDA‐IXA Symposium, September 20, 2017. Xenotransplantation 2017; 24. [PMID: 29193342 DOI: 10.1111/xen.12365] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Peter Cowan
- Immunology Research Centre, St Vincent's Hospital, Melbourne, Victoria, Australia
| | - Jay A Fishman
- Infectious Disease Division and MGH Transplant Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Bernhard J Hering
- Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Muhammad M Mohiuddin
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Richard N Pierson
- Department of Surgery, University of Maryland School of Medicine, Baltimore VA Medical Center, Baltimore, MD, USA
| | - David H Sachs
- Columbia University Medical Center, New York City, NY, USA.,Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA
| | | | - John U Dennis
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ralf R Tönjes
- Paul-Ehrlich-Institut, Federal Institute for Vaccines and Biomedicines, Division of Medical Biotechnology, Langen, Germany
| |
Collapse
|
118
|
Abstract
PURPOSE OF REVIEW This article reviews recent progress in the field of lung xenotransplantation, including mechanisms of xenograft injury, and the influence of mechanism-directed genetic modifications and other interventions that may soon enable therapeutic use of pig lungs in humans. RECENT FINDINGS An extensive series of lung xenotransplantation experiments demonstrates that multiple genetic modifications targeting known xenogeneic lung injury mechanisms are associated with incremental improvements in lung survival or function. Addition of human complement (hCD46, hCD55), coagulation (hEPCR, hTBM, hTFPI, hCD39), or anti-inflammatory pathway regulatory genes (HO-1, HLA-E), and GalT and Neu5Gc gene knockout has each demonstrated protective effects on lung survival or function. In addition, drug treatments targeting key inflammatory and clotting pathways have been shown to attenuate residual mechanisms of lung injury. Work with other pig organs in primate models show that regimens based on costimulatory pathway blocking antibodies prolong xenograft function for months to years, suggesting that once initial lung inflammation mechanisms are fully controlled, clinically useful application of pig lung xenografts may soon be feasible. SUMMARY Genetic modification of pigs coupled with drugs targeting complement activation, coagulation, and inflammation have significantly increased duration of pig lung function in ex-vivo human blood perfusion models, and life-supporting lung xenograft survival in vivo.
Collapse
Affiliation(s)
- Chris Laird
- aDivision of Cardiac Surgery, Department of Surgery, University of Maryland School of Medicine bVA Maryland Healthcare System, Baltimore, Maryland, USA
| | | | | |
Collapse
|
119
|
Cimeno A, French BM, Powell JM, Phelps C, Ayares D, O'Neill NA, Laird CT, Pierson RN, Azimzadeh AM, Barth RN, LaMattina JC. Synthetic liver function is detectable in transgenic porcine livers perfused with human blood. Xenotransplantation 2017; 25. [PMID: 29067741 DOI: 10.1111/xen.12361] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/21/2017] [Accepted: 09/26/2017] [Indexed: 12/27/2022]
Abstract
In addition to immune barriers, molecular incompatibilities between species are predicted to limit pig liver survival in primate xenotransplantation models. Assessment and measurement of synthetic function of genetically modified porcine livers after ex vivo perfusion with human blood have not previously been described. Eight porcine livers from α1,3-galactosyl transferase knockout and human membrane cofactor (GalTKO.hCD46), six livers from GalTKO.hCD46 and N-glycolylneuraminic acid knockout (GalTKO.hCD46.Neu5GcKO), and six livers from GalTKO.hCD46 with humanized decay-accelerating factor (hCD55), endothelial protein C receptor (hEPCR), tissue factor pathway inhibitor (hTFPI), and integrin-associated protein (hCD47) (GalTKO.hCD46.hCD55.hEPCR.hTFPI.hCD47) pigs were perfused with human blood under physiologic conditions. Timed blood samples were tested for liver enzymes and for pig-specific albumin production via Western blot. Porcine albumin levels increased with time in all experiments. By densitometry, GalTKO.hCD46.Neu5GcKO livers had the highest albumin levels, measured both as total produced, and when controlled for perfusion duration, compared to GalTKO.hCD46 (P = .068) and GalTKO.hCD46.hCD55.hEPCR.hTFPI.hCD47 livers (P = .04). Porcine livers perfused with human blood demonstrated the synthetic ability to produce albumin in all cases. GalTKO.hCD46.Neu5GcKO pig livers demonstrated the most robust albumin production. This suggests that the Neu5GcKO phenotype provides a protective effect on the graft due to decreased human antibody recognition and graft injury.
Collapse
Affiliation(s)
- Arielle Cimeno
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Beth M French
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jessica M Powell
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | | | - Natalie A O'Neill
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christopher T Laird
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Richard N Pierson
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Agnes M Azimzadeh
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rolf N Barth
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - John C LaMattina
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
120
|
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
| |
Collapse
|
121
|
The Role of Costimulation Blockade in Solid Organ and Islet Xenotransplantation. J Immunol Res 2017; 2017:8415205. [PMID: 29159187 PMCID: PMC5660816 DOI: 10.1155/2017/8415205] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/17/2017] [Indexed: 12/17/2022] Open
Abstract
Pig-to-human xenotransplantation offers a potential bridge to the growing disparity between patients with end-stage organ failure and graft availability. Early studies attempting to overcome cross-species barriers demonstrated robust humoral immune responses to discordant xenoantigens. Recent advances have led to highly efficient and targeted genomic editing, drastically altering the playing field towards rapid production of less immunogenic porcine tissues and even the discussion of human xenotransplantation trials. However, as these humoral immune barriers to cross-species transplantation are overcome with advanced transgenics, cellular immunity to these novel xenografts remains an outstanding issue. Therefore, understanding and optimizing immunomodulation will be paramount for successful clinical xenotransplantation. Costimulation blockade agents have been introduced in xenotransplantation research in 2000 with anti-CD154mAb. Most recently, prolonged survival has been achieved in solid organ (kidney xenograft survival > 400 days with anti-CD154mAb, heart xenograft survival > 900 days, and liver xenograft survival 29 days with anti-CD40mAb) and islet xenotransplantation (>600 days with anti-CD154mAb) with the use of these potent experimental agents. As the development of novel genetic modifications and costimulation blocking agents converges, we review their impact thus far on preclinical xenotransplantation and the potential for future application.
Collapse
|
122
|
Cowan PJ, Tector AJ. The Resurgence of Xenotransplantation. Am J Transplant 2017; 17:2531-2536. [PMID: 28397351 DOI: 10.1111/ajt.14311] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/21/2017] [Accepted: 04/01/2017] [Indexed: 01/25/2023]
Abstract
There has been an upsurge of interest in xenotransplantation in recent years. This resurgence can attributed to a combination of factors. First, there has been a dramatic improvement in efficacy in several preclinical models, with maximum xenograft survival times increasing to 950 days for islets, 945 days for hearts, and 310 days for kidneys. Second, the rapid development of genome editing technology (particularly the advent of clustered regularly interspaced short palindromic repeats/Cas9) has revolutionized the capacity to generate new donor pigs with multiple protective genetic modifications; what once took many years to achieve can now be performed in months, with much greater precision and scope. Third, the specter of porcine endogenous retrovirus (PERV) has receded significantly. There has been no evidence of PERV transmission in clinical trials and preclinical models, and improved screening methods and new options for the treatment or even elimination of PERV are now available. Balancing these positive developments are several remaining challenges, notably the heavy and often clinically inapplicable immunosuppression required to prevent xenograft rejection. Nonetheless, the potential for xenotransplantation as a solution to the shortage of human organs and tissues for transplantation continues to grow.
Collapse
Affiliation(s)
- P J Cowan
- Immunology Research Centre, St Vincent's Hospital Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Victoria, Australia
| | - A J Tector
- School of Medicine, University of Alabama, Birmingham, AL
| |
Collapse
|
123
|
Li T, Lee W, Hara H, Long C, Ezzelarab M, Ayares D, Huang H, Wang Y, Cooper DK, Iwase H. An Investigation of Extracellular Histones in Pig-To-Baboon Organ Xenotransplantation. Transplantation 2017; 101:2330-2339. [PMID: 28157735 PMCID: PMC5856196 DOI: 10.1097/tp.0000000000001676] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serum (extracellular) histone levels are increased in inflammatory states and in the presence of coagulation dysfunction, for example, trauma, chemical/ischemic injury, infection. There is increasing evidence of a systemic inflammatory response associated with the presence of a pig xenograft in a nonhuman primate. We evaluated extracellular histone levels in baboons with various pig xenografts. METHODS We measured serum histones in baboons with pig heterotopic heart (n = 8), life-supporting kidney (n = 5), orthotopic liver (n = 4), and artery patch (n = 9) grafts by enzyme-linked immunosorbent assay. C-reactive protein (CRP), free triiodothyronine (fT3), serum amyloid A (SAA), and platelet counts were also measured, all of which may provide an indication of an inflammatory state. We investigated the effect of histones on platelet aggregation and on cytotoxicity of pig cells in vitro. RESULTS Serum histones increased when baboons developed consumptive coagulopathy (eg, thrombocytopenia) or infection. CRP levels tended to be higher and fT3 levels lower when consumptive coagulopathy developed. Measurement of SAA correlated fairly well with CRP and indicated the state of inflammation. Treatment of the recipient with tocilizumab reduced the level of serum histones, CRP, and SAA, and increased the level of fT3 and platelet counts. In vitro, histone-induced platelet aggregation and endothelial cell apoptosis were both significantly reduced by the NF-κB pathway inhibitor, parthenolide. CONCLUSIONS These noninvasive assays may be useful for monitoring the health status of nonhuman primate recipients of pig organ grafts and may help in management after xenotransplantation. Tocilizumab and NF-κB inhibitors might prove valuable in reducing the inflammatory response to a pig xenograft.
Collapse
Affiliation(s)
- Tao Li
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
| | - 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
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Hai Huang
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi Wang
- Center for Kidney Transplantation, 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, USA
| | - Hayato Iwase
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
124
|
Shrock E, Güell M. CRISPR in Animals and Animal Models. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 152:95-114. [PMID: 29150007 DOI: 10.1016/bs.pmbts.2017.07.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CRISPR-Cas9 has revolutionized the generation of transgenic animals. This system has demonstrated an unprecedented efficiency, multiplexability, and ease of use, thereby reducing the time and cost required for genome editing and enabling the production of animals with more extensive genetic modifications. It has also been shown to be applicable to a wide variety of animals, from early-branching metazoans to primates. Genome-wide screens in model organisms have been performed, accurate models of human diseases have been constructed, and potential therapies have been tested and validated in animal models. Several achievements in genetic modification of animals have been translated into products for the agricultural and pharmaceutical industries. Based on the remarkable progress to date, one may anticipate that in the future, CRISPR-Cas9 technology will enable additional far-reaching advances, including understanding the bases of diseases with complex genetic origins, engineering animals to produce organs for human transplantation, and genetically transforming entire populations of organisms to prevent the spread of disease.
Collapse
Affiliation(s)
- Ellen Shrock
- Biological and Biomedical Sciences, Harvard University, Boston, MA, United States; Harvard Medical School, Boston, MA, United States
| | - Marc Güell
- Harvard Medical School, Boston, MA, United States; Pompeu Fabra University, Barcelona, Spain.
| |
Collapse
|
125
|
Potential Antigens Involved in Delayed Xenograft Rejection in a Ggta1/Cmah Dko Pig-to-Monkey Model. Sci Rep 2017; 7:10024. [PMID: 28855711 PMCID: PMC5577312 DOI: 10.1038/s41598-017-10805-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 08/15/2017] [Indexed: 12/25/2022] Open
Abstract
When hyperacute rejection is avoided by deletion of Gal expression in the pig, delayed xenograft rejection (DXR) becomes a major immunologic barrier to successful xenotransplantation. This study was to investigate the potential antigens involved in DXR. We isolated primary renal microvascular endothelial cells (RMEC) and aortic endothelial cells (AEC) from a GGTA1/CMAH double-knockout (DKO) pig (and a GGTA1-KO pig) and immunized cynomolgus monkeys with both of these cells. After sensitization, monkey serum antibody binding and cytotoxicity to RMEC was significantly higher than to AEC(p < 0.05), suggesting that RMEC are more immunogenic than AEC. Transcriptome sequencing of GGTA1/CMAH DKO pigs indicated that the expression of 1,500 genes was higher in RMEC than in AEC, while expression of 896 genes was lower. Next, we selected 101 candidate genes expressed only in pig RMEC, but not in pig AEC or in monkey or human RMEC. When these genes were knocked out individually in GGTA1/CMAH DKO RMEC, 32 genes were associated with reduced antibody binding, indicating that these genes might be primary immunologic targets involved in DXR. These genes may be important candidates for deletion in producing pigs against which there is a reduced primate immune response in pig kidney xenograft.
Collapse
|
126
|
Cooper DK, Pierson RN, Hering BJ, Mohiuddin MM, Fishman JA, Denner J, Ahn C, Azimzadeh AM, Buhler LH, Cowan PJ, Hawthorne WJ, Kobayashi T, Sachs DH. Regulation of Clinical Xenotransplantation-Time for a Reappraisal. Transplantation 2017; 101:1766-1769. [PMID: 28737658 PMCID: PMC5702547 DOI: 10.1097/tp.0000000000001683] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The continual critical shortage of organs and cells from deceased human donors has stimulated research in the field of cross-species transplantation (xenotransplantation), with the pig selected as the most suitable potential source of organs. Since the US Food and Drug Administration concluded a comprehensive review of xenotransplantation in 2003, considerable progress has been made in the experimental laboratory to improve cell and organ xenograft survival in several pig-to-nonhuman primate systems that offer the best available models to predict clinical outcomes. Survival of heart, kidney, and islet grafts in nonhuman primates is now being measured in months or even years. The potential risks associated with xenotransplantation, for example, the transfer of an infectious microorganism, that were highlighted in the 2003 Food and Drug Administration guidance and subsequent World Health Organization consensus documents have been carefully studied and shown to be either less likely than previously thought or readily manageable by donor selection or recipient management strategies. In this context, we suggest that the national regulatory authorities worldwide should re-examine their guidelines and regulations regarding xenotransplantation, so as to better enable design and conduct of safe and informative clinical trials of cell and organ xenotransplantation when and as supported by the preclinical data. We identify specific topics that we suggest require reconsideration.
Collapse
Affiliation(s)
- David K.C. Cooper
- Thomas E Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, PA
| | - Richard N. Pierson
- Division of Cardiac Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD
| | - Bernhard J. Hering
- Schulze Diabetes Institute, Department of Surgery, University of Minnesota, Minneapolis, MN
| | - Muhammad M. Mohiuddin
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Jay A. Fishman
- MGH Transplantation Center and Transplant Infectious Disease and Compromised Host Program, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | | | - Curie Ahn
- Transplantation Research Institute, College of Medicine, Seoul National University, Seoul, South Korea
| | - Agnes M. Azimzadeh
- Division of Cardiac Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD
| | - Leo H. Buhler
- Department of Surgery, University Hospital Geneva, Geneva, Switzerland
| | - Peter J. Cowan
- Immunology Research Center, St Vincent's Hospital Melbourne, University of Melbourne, Melbourne, Victoria, Australia
| | - Wayne J. Hawthorne
- Department of Surgery, Westmead Clinical School, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
| | - Takaaki Kobayashi
- Department of Renal Transplant Surgery, Aichi Medical University School of Medicine, Nagakute, Japan
| | | |
Collapse
|
127
|
Zhang Z, Li X, Zhang H, Zhang X, Chen H, Pan D, Ji H, Zhou L, Ling J, Zhou J, Yue S, Wang D, Yang Z, Tao K, Dou K. Cytokine profiles in Tibetan macaques following α-1,3-galactosyltransferase-knockout pig liver xenotransplantation. Xenotransplantation 2017; 24. [PMID: 28714241 DOI: 10.1111/xen.12321] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 06/08/2017] [Accepted: 06/16/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Pig-to-nonhuman primate orthotopic liver xenotransplantation is often accompanied by thrombocytopenia and coagulation disorders. Furthermore, the release of cytokines can trigger cascade reactions of coagulation and immune attacks within transplant recipients. To better elucidate the process of inflammation in liver xenograft recipients, we utilized a modified heterotopic auxiliary liver xenotransplantation model for xeno-immunological research. We studied the cytokine profiles and the relationship between cytokine levels and xenograft function after liver xenotransplantation. METHODS Appropriate donor and recipient matches were screened using complement-dependent cytotoxicity assays. Donor liver grafts from α1,3-galactosyltransferase gene-knockout (GTKO) pigs or GTKO pigs additionally transgenic for human CD47 (GTKO/CD47) were transplanted into Tibetan macaques via two different heterotrophic auxiliary liver xenotransplantation procedures. The cytokine profiles, hepatic function, and coagulation parameters were monitored during the clinical course of xenotransplantation. RESULTS Xenograft blood flow was stable in recipients after heterotopic auxiliary transplantation. A Doppler examination indicated that the blood flow speed was faster in the hepatic artery (HA) and hepatic vein (HV) of xenografts subjected to the modified Sur II (HA-abdominal aorta+HV-inferior vena cava) procedure than in those subjected to our previously reported Sur I (HA-splenic artery+HV-left renal vein) procedure. Tibetan macaques receiving liver xenografts did not exhibit severe coagulation disorders or immune rejection. Although the recipients did suffer from a rapid loss of platelets, this loss was mild. In blood samples dynamically collected after xenotransplantation (post-Tx), dramatic increases in the levels of monocyte chemoattractant protein 1, interleukin (IL)-8, granulocyte-macrophage colony-stimulating factor, IL-6, and interferon gamma-induced protein 10 were observed at 1 hour post-Tx, even under immunosuppression. We further confirmed that the elevation in individual cytokine levels was correlated with the onset of graft damage. Finally, the release of cytokines might contribute to leukocyte infiltration in the xenografts. CONCLUSION Here, we established a modified auxiliary liver xenotransplantation model resulting in near-normal hepatic function. Inflammatory cytokines might contribute to early damage in liver xenografts. Controlling the systemic inflammatory response of recipients might prevent early post-Tx graft dysfunction.
Collapse
Affiliation(s)
- Zhuochao Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiao Li
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Hong Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xuan Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Hui Chen
- Laboratory Animal Institute, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Dengke Pan
- Institute of Animal Science of Chinese Agriculture Sciences Academy, Beijing, China
| | - Hongchen Ji
- Department of Hepatobiliary Surgery, The Chinese PLA General Hospital, Beijing, China
| | - Liang Zhou
- Laboratory Animal Institute, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Juan Ling
- Laboratory Animal Institute, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Jingshi Zhou
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Shuqiang Yue
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Desheng Wang
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Zhaoxu Yang
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Kaishan Tao
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Kefeng Dou
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| |
Collapse
|
128
|
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.
Collapse
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)
| |
Collapse
|
129
|
Cooper DK, Wijkstrom M, Hariharan S, Chan JL, Singh A, Horvath K, Mohiuddin M, Cimeno A, Barth RN, LaMattina JC, Pierson RN. Selection of Patients for Initial Clinical Trials of Solid Organ Xenotransplantation. Transplantation 2017; 101:1551-1558. [PMID: 27906824 PMCID: PMC5453852 DOI: 10.1097/tp.0000000000001582] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Several groups have reported extended survival of genetically engineered pig organs in nonhuman primates, varying from almost 10 months for life-supporting kidney grafts and more than 2 years for non-life-supporting heart grafts to less than 1 month for life-supporting liver and lung grafts. We have attempted to define groups of patients who may not have an option to wait for an allograft. These include kidney, heart, and lung candidates who are highly-allosensitized. In addition, some kidney candidates (who have previously lost at least 2 allografts from rapid recurrence of native kidney disease) have a high risk of further recurrence and will not be offered a repeat allotransplant. Patients with complex congenital heart disease, who may have undergone previous palliative surgical procedures, may be unsuitable for ventricular assist device implantation. Patients dying of fulminant hepatic failure, for whom no alternative therapy is available, may be candidates for a pig liver, even if only as a bridge until an allograft becomes available. When the results of pig organ xenotransplantation in nonhuman primates suggest a realistic potential for success of a pilot clinical trial, highly selected patients should be offered participation.
Collapse
Affiliation(s)
- David K.C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Martin Wijkstrom
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Sundaram Hariharan
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| | - Joshua L. Chan
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Avneesh Singh
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Keith Horvath
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Muhammad Mohiuddin
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Arielle Cimeno
- Division of Transplantation Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD
| | - Rolf N. Barth
- Division of Transplantation Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD
| | - John C. LaMattina
- Division of Transplantation Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD
| | - Richard N. Pierson
- Division of Cardiac Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD, USA
| |
Collapse
|
130
|
Lee SC, Lee H, Oh KB, Hwang IS, Yang H, Park MR, Ock SA, Woo JS, Im GS, Hwang S. Production and Breeding of Transgenic Cloned Pigs Expressing Human CD73. Dev Reprod 2017; 21:157-165. [PMID: 28785737 PMCID: PMC5532308 DOI: 10.12717/dr.2017.21.2.157] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 11/17/2022]
Abstract
One of the reasons to causing blood coagulation in the tissue of xenografted
organs was known to incompatibility of the blood coagulation and
anti-coagulation regulatory system between TG pigs and primates. Thus,
overexpression of human CD73 (hCD73) in the pig endothelial cells is considered
as a method to reduce coagulopathy after pig-to-non-human-primate
xenotransplantation. This study was performed to produce and breed transgenic
pigs expressing hCD73 for the studies immune rejection responses and could
provide a successful application of xenotransplantation. The transgenic cells
were constructed an hCD73 expression vector under control porcine Icam2 promoter
(pIcam2-hCD73) and established donor cell lines expressing hCD73. The numbers of
transferred reconstructed embryos were 127 ± 18.9. The pregnancy and delivery
rate of surrogates were 8/18 (44%) and 3/18 (16%). The total number of delivered
cloned pigs were 10 (2 alive, 7 mummy, and 1 died after birth). Among them,
three live hCD73-pigs were successfully delivered by Caesarean section, but one
was dead after birth. The two hCD73 TG cloned pigs had normal reproductive
ability. They mated with wild type (WT) MGH (Massachusetts General Hospital)
female sows and produced totally 16 piglets. Among them, 5 piglets were
identified as hCD73 TG pigs. In conclusion, we successfully generated the hCD73
transgenic cloned pigs and produced their litters by natural mating. It can be
possible to use a mate for the production of multiple transgenic pigs such as
α-1,3-galactosyltransferase knock-out /hCD46 for xenotransplantation.
Collapse
Affiliation(s)
- Seung-Chan Lee
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Haesun Lee
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Keon Bong Oh
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - In-Sul Hwang
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Hyeon Yang
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Mi-Ryung Park
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Sun-A Ock
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Jae-Seok Woo
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Gi-Sun Im
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| | - Seongsoo Hwang
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Wanju 55365, Republic of Korea
| |
Collapse
|
131
|
Liu Z, Hu W, He T, Dai Y, Hara H, Bottino R, Cooper DKC, Cai Z, Mou L. Pig-to-Primate Islet Xenotransplantation: Past, Present, and Future. Cell Transplant 2017; 26:925-947. [PMID: 28155815 PMCID: PMC5657750 DOI: 10.3727/096368917x694859] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/21/2017] [Indexed: 12/17/2022] Open
Abstract
Islet allotransplantation results in increasing success in treating type 1 diabetes, but the shortage of deceased human donor pancreata limits progress. Islet xenotransplantation, using pigs as a source of islets, is a promising approach to overcome this limitation. The greatest obstacle is the primate immune/inflammatory response to the porcine (pig) islets, which may take the form of rapid early graft rejection (the instant blood-mediated inflammatory reaction) or T-cell-mediated rejection. These problems are being resolved by the genetic engineering of the source pigs combined with improved immunosuppressive therapy. The results of pig-to-diabetic nonhuman primate islet xenotransplantation are steadily improving, with insulin independence being achieved for periods >1 year. An alternative approach is to isolate islets within a micro- or macroencapsulation device aimed at protecting them from the human recipient's immune response. Clinical trials using this approach are currently underway. This review focuses on the major aspects of pig-to-primate islet xenotransplantation and its potential for treatment of type 1 diabetes.
Collapse
Affiliation(s)
- Zhengzhao Liu
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, P.R. China
| | - Wenbao Hu
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, P.R. China
| | - Tian He
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, P.R. China
| | - Yifan Dai
- Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Hidetaka Hara
- Xenotransplantation Program/Department of Surgery, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rita Bottino
- Institute for Cellular Therapeutics, Allegheny-Singer Research Institute, Pittsburgh, PA, USA
| | - David K. C. Cooper
- Xenotransplantation Program/Department of Surgery, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Zhiming Cai
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, P.R. China
| | - Lisha Mou
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, P.R. China
| |
Collapse
|
132
|
Prolonged Survival of Pig Skin on Baboons After Administration of Pig Cells Expressing Human CD47. Transplantation 2017; 101:316-321. [PMID: 27232934 DOI: 10.1097/tp.0000000000001267] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Successful xenotransplantation will likely depend, in part, on the induction of immunological tolerance, because the high levels of immunosuppression otherwise required would likely have unacceptable side effects. Rapid clearance of administered porcine hematopoietic stem cells by primate macrophages has hampered previous attempts to induce tolerance through mixed hematopoietic chimerism across a pig-to-primate barrier. Phagocytosis is normally inhibited by binding of cell surface protein CD47 to macrophage signal regulatory protein α receptors. However, pig CD47 has previously been shown to be ineffective in transducing signals through primate signal regulatory protein α. METHODS Mobilized peripheral blood hematopoietic cells from transgenic swine expressing high or low levels of human CD47 were infused into conditioned baboons at 3 time points over a 9-week period. Xenogeneic peripheral blood chimerism was assessed after each infusion. Split thickness skin grafts from the hematopoietic cell donor swine were placed on recipients 5 weeks after the last cell infusion and 7 weeks after the discontinuation of all immunosuppression to test immune response. RESULTS The level and duration of transient chimerism were substantially greater in baboons receiving hematopoietic cells from a pig expressing high levels of human CD47. Skin graft survival on high CD47 recipients was prolonged as well, in 1 case showing no signs of rejection at least 53 days after placement. CONCLUSIONS Prolongation of transient porcine chimerism via transgenic expression of human CD47 in a primate model is associated with an immune modulating effect, leading to markedly prolonged survival of donor swine skin xenografts that may be applicable to clinical solid organ xenotransplantation.
Collapse
|
133
|
Zhang Z, Gao B, Zhao C, Long C, Qi H, Ezzelarab M, Cooper DK, Hara H. The impact of serum incubation time on IgM/IgG binding to porcine aortic endothelial cells. Xenotransplantation 2017; 24. [PMID: 28547819 DOI: 10.1111/xen.12312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 12/25/2022]
Abstract
The results of the assay for measuring anti-non-Gal antibodies (which affect pig xenograft survival) in recipients are important. Serum incubation time and concentration may be important factors in the extent of antibody binding to the graft. The aim of this in vitro study was to determine the optimal incubation time and serum concentration for measuring anti-non-Gal antibody binding to porcine aortic endothelial cells (pAECs). Pooled human, naive, and sensitized baboon sera were incubated with wild-type, α1,3-galactosyltransferase gene-knockout (GTKO), and GTKO/human CD55 pAECs. IgM/IgG binding to pAECs after varying serum incubation times (0.5, 1, 2, and 3 hour) and concentrations (5, 10, 20, and 40 μL) was determined by flow cytometry. An increase in incubation time from 30 minutes to 2 hour was associated with increases in anti-non-Gal IgM/IgG binding to GTKO and GTKO/hCD55 pAECs of pooled human, naive and sensitized baboon sera (P<.05). Pooled human serum showed a significant increase in anti-non-Gal IgM (1.5 times) and a minimal increase in anti-non-Gal IgG antibody binding. IgM/IgG binding of sensitized baboon serum to GTKO pAECs after 2-hour incubation was 1.5 times and 2 times greater than after 30-minutes incubation, respectively, whereas naïve baboon sera showed minimal (non-significant) increase in anti-non-Gal IgM/IgG antibody binding. With 2-hour incubation, increasing the serum concentration from 5 μL to 20 μL significantly increased antibody binding to non-Gal antigens in pooled human and sensitized baboon serum. With naïve baboon serum, only IgG was significantly increased. Increasing the serum incubation time contributed to improve the sensitivity of detecting anti-non-Gal antibodies, without affecting cell viability in vitro.
Collapse
Affiliation(s)
- Zhongqiang Zhang
- Department of Organ Transplantation and General Surgery, Second Xiangya Hospital of the Central South University, Hunan, Changsha, China.,Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Bingsi Gao
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Chengjiang Zhao
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Haizhi Qi
- Department of Organ Transplantation and General Surgery, Second Xiangya Hospital of the Central South University, Hunan, Changsha, China
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - David Kc Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| |
Collapse
|
134
|
Abstract
BACKGROUND The rapidly improving tools of genetic engineering may make it possible to overcome the humoral immune barrier that prevents xenotransplantation. We hypothesize that levels of human antibody binding to donor tissues from swine must approximate the antibody binding occurring in allotransplantation. It is uncertain if this is an attainable goal. Here we perform an initial analysis of this issue by comparing human antibody binding to red blood cells (RBC) isolated from knockout swine and to allogeneic or autologous human RBC. METHODS Human sera were incubated with RBC isolated from various genetically engineered swine or from humans. The level of IgG and IgM binding to these cells were compared using either flow cytometry or a novel mass spectrometric assay. RESULTS Mass spectroscopic quantitation of human antibody binding demonstrated that as few as 3 gene inactivations can reduce the levels human antibody binding to swine RBC that is as low as autologous human RBC. Flow cytometry showed that RBC from 2-gene knockout swine exhibited less human antibody binding than human blood group O allogeneic RBC in 22% of tested sera. Deletion of a third gene from pigs resulted in 30% of human samples having less IgG and IgM RBC xenoreactivity than alloreactivity. CONCLUSIONS Xenoantigenicity of swine RBC can be eliminated via gene disruption. These results suggest that the gene knockout approach may be able reduce antigenicity in other pig tissues to levels that enable the xenotransplantation humoral barrier to be overcome.
Collapse
|
135
|
Martens GR, Reyes LM, Li P, Butler JR, Ladowski JM, Estrada JL, Sidner RA, Eckhoff DE, Tector M, Tector AJ. Humoral Reactivity of Renal Transplant-Waitlisted Patients to Cells From GGTA1/CMAH/B4GalNT2, and SLA Class I Knockout Pigs. Transplantation 2017; 101:e86-e92. [PMID: 28114170 DOI: 10.1097/tp.0000000000001646] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Antipig antibodies are a barrier to clinical xenotransplantation. We evaluated antibody binding of waitlisted renal transplant patients to 3 glycan knockout (KO) pig cells and class I swine leukocyte antigens (SLA). METHODS Peripheral blood mononuclear cells from SLA identical wild type (WT), α1, 3-galactosyltransferase (GGTA1) KO, GGTA1/ cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) KO, and GGTA1/ CMAH /b1,4 N-acetylgalactosaminyl transferase (B4GalNT2) KO pigs were screened for human antibody binding using flow cytometric crossmatch (FCXM). Sera from 820 patients were screened on GGTA1/CMAH/B4GalNT2 KO cells and a subset with elevated binding was evaluated further. FCXM was performed on SLA intact cells and GGTA1/SLA class I KO cells after depletion with WT pig RBCs to remove cell surface reactive antibodies, but leave SLA antibodies. Lastly, human and pig reactive antibodies were eluted and tested for cross-species binding and reactivity to single-antigen HLA beads. RESULTS Sequential glycan KO modifications significantly reduce antibody binding of waitlisted patients. Sera exhibiting elevated binding without reduction after depletion with WT RBCs demonstrate reduced binding to SLA class I KO cells. Human IgG, eluted from human and pig peripheral blood mononuclear cells, interacted across species and bound single-antigen HLA beads in common epitope-restricted patterns. CONCLUSIONS Many waitlisted patients have minimal xenoreactive antibody binding to the triple KO pig, but some HLA antibodies in sensitized patients cross-react with class I SLA. SLA class I is a target for genome editing in xenotransplantation.
Collapse
Affiliation(s)
- Gregory R Martens
- 1 Department of Surgery, University of Alabama at Birmingham, Birmingham, AL. 2 Department of Surgery, Indiana University, School of Medicine, Indianapolis, IN. 3 Transplant Surgery, University of Alabama at Birmingham, Birmingham, AL
| | | | | | | | | | | | | | | | | | | |
Collapse
|
136
|
Iwase H, Hara H, Ezzelarab M, Li T, Zhang Z, Gao B, Liu H, Long C, Wang Y, Cassano A, Klein E, Phelps C, Ayares D, Humar A, Wijkstrom M, Cooper DKC. Immunological and physiological observations in baboons with life-supporting genetically engineered pig kidney grafts. Xenotransplantation 2017; 24:10.1111/xen.12293. [PMID: 28303661 PMCID: PMC5397334 DOI: 10.1111/xen.12293] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/22/2016] [Accepted: 01/26/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Genetically engineered pigs could provide a source of kidneys for clinical transplantation. The two longest kidney graft survivals reported to date have been 136 and 310 days, but graft survival >30 days has been unusual until recently. METHODS Donor pigs (n=4) were on an α1,3-galactosyltransferase gene-knockout (GTKO)/human complement regulatory protein (CD46) background (GTKO/CD46). In addition, the pigs were transgenic for at least one human coagulation regulatory protein. Two baboons received a kidney from a six-gene pig (GroupA) and two from a three-gene pig (GroupB). Immunosuppressive therapy was identical in all four cases and consisted of anti-thymoglobulin (ATG)+anti-CD20mAb (induction) and anti-CD40mAb+rapamycin+corticosteroids (maintenance). Anti-TNF-α and anti-IL-6R mAbs were administered to reduce the inflammatory response. Baboons were followed by clinical/laboratory monitoring of immune/coagulation/inflammatory/physiological parameters. At biopsy or euthanasia, the grafts were examined by microscopy. RESULTS The two GroupA baboons remained healthy with normal renal function >7 and >8 months, respectively, but then developed infectious complications. However, no features of a consumptive coagulopathy, eg, thrombocytopenia and reduction of fibrinogen, or of a protein-losing nephropathy were observed. There was no evidence of an elicited anti-pig antibody response, and histology of biopsies taken at approximately 4, 6, and 7 months and at necropsy showed no significant abnormalities. In contrast, both GroupB baboons developed features of a consumptive coagulopathy and required euthanasia on day 12. CONCLUSIONS The combination of (i) a graft from a specific six-gene genetically modified pig, (ii) an effective immunosuppressive regimen, and (iii) anti-inflammatory therapy prevented immune injury, a protein-losing nephropathy, and coagulation dysfunction for >7 months. Although the number of experiments is very limited, our impression is that expression of human endothelial protein C receptor (±CD55) in the graft is important if coagulation dysregulation is to be avoided.
Collapse
Affiliation(s)
- Hayato Iwase
- 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 Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tao Li
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
| | - Zhongqiang Zhang
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
- Department of General Surgery, Second Xiangya Hospital of the Central South University, Changsha, Hunan, China
| | - Bingsi Gao
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
| | - Hong Liu
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
- Department of General Surgery, First Hospital of Shanxi Medical University, Taiyuan, China
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi Wang
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China
| | - Amy Cassano
- Division of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh, PA, USA
| | - Edwin Klein
- Division of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh, PA, USA
| | | | | | - Abhinav Humar
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Martin Wijkstrom
- 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
| |
Collapse
|
137
|
Aristizabal AM, Caicedo LA, Martínez JM, Moreno M, J Echeverri G. Clinical xenotransplantation, a closer reality: Literature review. Cir Esp 2017; 95:62-72. [PMID: 28237390 DOI: 10.1016/j.ciresp.2016.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/29/2016] [Accepted: 12/15/2016] [Indexed: 01/22/2023]
Abstract
Xenotransplantation could provide an unlimited supply of organs and solve the current shortage of organs for transplantation. To become a reality in clinical practice, the immunological and physiological barriers and the risk of xenozoonosis that they possess should be resolved. From the immunological point of view, in the last 30 years a significant progress in the production of transgenic pigs has prevented the hyperacute rejection. About xenozoonosis, attention has been focused on the risk of transmission of porcine endogenous retroviruses; however, today, it is considered that the risk is very low and the inevitable transmission should not prevent the clinical xenotransplantation. Regarding the physiological barriers, encouraging results have been obtained and it's expected that the barriers that still need to be corrected can be solved in the future through genetic modifications.
Collapse
Affiliation(s)
- Ana María Aristizabal
- Centro de Investigaciones Clínicas, Fundación Valle del Lili, Cali, Colombia; Centro para la Investigación en Cirugía Avanzada y Trasplantes (CICAT), Universidad Icesi, Cali, Colombia
| | - Luis Armando Caicedo
- Centro de Investigaciones Clínicas, Fundación Valle del Lili, Cali, Colombia; Centro para la Investigación en Cirugía Avanzada y Trasplantes (CICAT), Universidad Icesi, Cali, Colombia
| | - Juan Manuel Martínez
- Centro de Investigaciones Clínicas, Fundación Valle del Lili, Cali, Colombia; Centro para la Investigación en Cirugía Avanzada y Trasplantes (CICAT), Universidad Icesi, Cali, Colombia
| | - Manuel Moreno
- Centro de Investigaciones Clínicas, Fundación Valle del Lili, Cali, Colombia; Centro para la Investigación en Cirugía Avanzada y Trasplantes (CICAT), Universidad Icesi, Cali, Colombia
| | - Gabriel J Echeverri
- Centro de Investigaciones Clínicas, Fundación Valle del Lili, Cali, Colombia; Centro para la Investigación en Cirugía Avanzada y Trasplantes (CICAT), Universidad Icesi, Cali, Colombia.
| |
Collapse
|
138
|
Denner J. Xenotransplantation - A special case of One Health. One Health 2017; 3:17-22. [PMID: 28616498 PMCID: PMC5454160 DOI: 10.1016/j.onehlt.2017.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/25/2017] [Accepted: 02/07/2017] [Indexed: 12/20/2022] Open
Abstract
The chronic shortage of human transplants to treat tissue and organ failure has led to the development of xenotransplantation, the transplantation of cells, tissues and organs from another species to human recipients. For a number of reasons, pigs are best suited as donor animals. Successful, routine xenotransplantation would have an enormous impact on the health of the human population, including the young, who sometimes require a replacement organ or islet cells, but especially the elderly, who more often suffer the consequences of organ failure. The first form of xenotransplantation applied to humans is the use of pig islet cells to treat insulin-dependent diabetes, a procedure that will have a significant economic impact. However, although xenotransplantation using pig cells, tissues and organs may save and prolong the lives of patients, it may also be associated with the transmission of porcine microorganisms to the recipient, eventually resulting in emerging infectious diseases. For this reason, the health of both the donor animals and the human recipients represents a special and sensitive case of the One Health concept. Basic research leading to strategies how to prevent transmission of porcine microorganisms by selection of virus-free animals, treatment of donor pigs by antiviral drugs, vaccines, colostrum deprivation, early weaning, Caesarean delivery, embryo transfer and/or gene editing should be undertaken to supply an increasing number of potential recipients with urgently required transplants. The methods developed for the detection and elimination of porcine microorganisms in the context of xenotransplantation will also contribute to an improvement in the health of pig populations in general and an increase in the quality of meat products. At present, there is evidence for transmission of porcine viruses to humans eating pork and having contact with pigs, however the impact of these viruses on public health is still unknown.
Collapse
Affiliation(s)
- Joachim Denner
- Corresponding author at: Robert Koch Institute, Nordufer 20, D-13353 Berlin, Germany.Robert Koch InstituteNordufer 20BerlinD-13353Germany
| |
Collapse
|
139
|
Cooper DKC. The White House Organ Summit. Am J Transplant 2017; 17:576. [PMID: 27647663 DOI: 10.1111/ajt.14056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- D K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA
| |
Collapse
|
140
|
Iwase H, Liu H, Schmelzer E, Ezzelarab M, Wijkstrom M, Hara H, Lee W, Singh J, Long C, Lagasse E, Gerlach JC, Cooper DKC, Gridelli B. Transplantation of hepatocytes from genetically engineered pigs into baboons. Xenotransplantation 2017; 24. [PMID: 28130881 DOI: 10.1111/xen.12289] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/23/2016] [Accepted: 12/27/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND Some patients with acute or acute-on-chronic hepatic failure die before a suitable human liver allograft becomes available. Encouraging results have been achieved in such patients by the transplantation of human hepatocyte progenitor cells from fetal liver tissue. The aim of the study was to explore survival of hepatocytes from genetically engineered pigs after direct injection into the spleen and other selected sites in immunosuppressed baboons to monitor the immune response and the metabolic function and survival of the transplanted hepatocytes. METHODS Baboons (n=3) were recipients of GTKO/hCD46 pig hepatocytes. All three baboons received anti-thymocyte globulin (ATG) induction and tapering methylprednisolone. Baboon 1 received maintenance immunosuppressive therapy with tacrolimus and rapamycin. Baboons 2 and 3 received an anti-CD40mAb/rapamycin-based regimen that prevents sensitization to pig solid organ grafts. The baboons were euthanized 4 or 5 weeks after hepatocyte transplantation. The baboon immune response was monitored by the measurement of anti-non-Gal IgM and IgG antibodies (by flow cytometry) and CFSE-mixed lymphocyte reaction. Monitoring for hepatocyte survival and function was by (i) real-time PCR detection of porcine DNA, (ii) real-time PCR for porcine gene expression, and (iii) pig serum albumin levels (by ELISA). The sites of hepatocyte injection were examined microscopically. RESULTS Detection of porcine DNA and porcine gene expression was minimal at all sites of hepatocyte injection. Serum levels of porcine albumen were very low-500-1000-fold lower than in baboons with orthotopic pig liver grafts, and approximately 5000-fold lower than in healthy pigs. No hepatocytes or infiltrating immune cells were seen at any of the injection sites. Two baboons (Baboons 1 and 3) demonstrated a significant increase in anti-pig IgM and an even greater increase in IgG, indicating sensitization to pig antigens. DISCUSSION AND CONCLUSIONS As a result of this disappointing experience, the following points need to be considered. (i) Were the isolated pig hepatocytes functionally viable? (ii) Are pig hepatocytes more immunogenic than pig hearts, kidneys, artery patch grafts, or islets? (iii) Does injection of pig cells (antigens) into the spleen and/or lymph nodes stimulate a greater immune response than when pig tissues are grafted at other sites? (iv) Did the presence of the recipient's intact liver prevent survival and proliferation of pig hepatocytes? (v) Is pig CD47-primate SIRP-α compatibility essential? In conclusion, the transplantation of genetically engineered pig hepatocytes into multiple sites in immunosuppressed baboons was associated with very early graft failure. Considerable further study is required before clinical trials should be undertaken.
Collapse
Affiliation(s)
- Hayato Iwase
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hong Liu
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.,Department of General Surgery, First Hospital of Shanxi Medical University, Taiyuan, China
| | - Eva Schmelzer
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Martin Wijkstrom
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Whayoung Lee
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jagjit Singh
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eric Lagasse
- Department of Pathology, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jörg C Gerlach
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bruno Gridelli
- Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo, Italy
| |
Collapse
|
141
|
Bottino R, Knoll MF, Graeme-Wilson J, Klein EC, Ayares D, Trucco M, Cooper DK. Safe use of anti-CD154 monoclonal antibody in pig islet xenotransplantation in monkeys. Xenotransplantation 2017; 24:10.1111/xen.12283. [PMID: 28058735 PMCID: PMC5332295 DOI: 10.1111/xen.12283] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/11/2016] [Accepted: 11/14/2016] [Indexed: 12/27/2022]
Abstract
Anti-CD154mAb is a powerful co-stimulation blockade agent that is efficacious in preventing rejection, even in xenogeneic settings. It has been used in the majority of successful long-term pig-to-non-human primate islet transplantation models. However, its clinical use was halted as a result of thromboembolic complications that were also observed in preclinical and clinical organ transplantation models. An anti-CD154mAb was administered to 14 streptozotocin-induced diabetic cynomolgus monkey recipients of porcine islets, some of which received the agent for many months. Monkeys were monitored for complications, and blood monitoring was carried out frequently. After euthanasia, multiple biopsies of all organs were examined for histological features of thromboembolism. Anti-CD154mAb prevented rejection of genetically engineered pig islets in all monkeys. No significant complications were attributable specifically to anti-CD154mAb. There was no evidence of thromboembolism in multiple histological sections from all major organs, including the brain. Our data suggest that in diabetic monkeys with pig islet grafts, anti-CD154mAb would appear to be an effective and safe therapy, and is not associated with thromboembolic complications.
Collapse
Affiliation(s)
- Rita Bottino
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
| | - Michael F. Knoll
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
| | | | - Edwin C. Klein
- Division of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh PA, USA
| | | | - Massimo Trucco
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
| | - David K.C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
142
|
Renal xenotransplantation: experimental progress and clinical prospects. Kidney Int 2016; 91:790-796. [PMID: 27914702 DOI: 10.1016/j.kint.2016.08.035] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/09/2016] [Accepted: 08/18/2016] [Indexed: 12/17/2022]
Abstract
There are >100,000 patients waiting for kidney transplants in the United States and a vast need worldwide. Xenotransplantation, in the form of the transplantation of kidneys from genetically engineered pigs, offers the possibility of overcoming the chronic shortage of deceased and living human donors. These genetic manipulations can take the form of (i) knockout of pig genes that are responsible for the expression of antigens against which the primate (human or nonhuman primate) has natural "preformed" antibodies that bind and initiate complement-mediated destruction or (ii) the insertion of human transgenes that provide protection against the human complement, coagulation, or inflammatory responses. Between 1989 and 2015, pig kidney graft survival in nonhuman primates increased from 23 days to almost 10 months. There appear to be no clinically significant physiological incompatibilities in renal function between pigs and primates. The organ-source pigs will be housed in a biosecure environment, and thus the risk of transferring an exogenous potentially pathogenic microorganism will be less than that after allotransplantation. Although the risk associated with porcine endogenous retroviruses is considered small, techniques are now available whereby they could potentially be excluded from the pig. The US Food and Drug Administration suggests that xenotransplantation should be restricted to "patients with serious or life-threatening diseases for whom adequately safe and effective alternative therapies are not available." These might include those with (i) a high degree of allosensitization to human leukocyte antigens or (ii) rapid recurrence of primary disease in previous allografts. The potential psychosocial, regulatory, and legal aspects of clinical xenotransplantation are briefly discussed.
Collapse
|
143
|
Cooper DK, Matsumoto S, Abalovich A, Itoh T, Mourad NI, Gianello PR, Wolf E, Cozzi E. Progress in Clinical Encapsulated Islet Xenotransplantation. Transplantation 2016; 100:2301-2308. [PMID: 27482959 PMCID: PMC5077652 DOI: 10.1097/tp.0000000000001371] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
At the 2015 combined congress of the Cell Transplant Society, International Pancreas and Islet Transplant Association, and International Xenotransplantation Association, a symposium was held to discuss recent progress in pig islet xenotransplantation. The presentations focused on 5 major topics - (1) the results of 2 recent clinical trials of encapsulated pig islet transplantation, (2) the inflammatory response to encapsulated pig islets, (3) methods to improve the secretion of insulin by pig islets, (4) genetic modifications to the islet-source pigs aimed to protect the islets from the primate immune and/or inflammatory responses, and (5) regulatory aspects of clinical pig islet xenotransplantation. Trials of microencapsulated porcine islet transplantation to treat unstable type 1 diabetic patients have been associated with encouraging preliminary results. Further advances to improve efficacy may include (1) transplantation into a site other than the peritoneal cavity, which might result in better access to blood, oxygen, and nutrients; (2) the development of a more biocompatible capsule and/or the minimization of a foreign body reaction; (3) pig genetic modification to induce a greater secretion of insulin by the islets, and/or to reduce the immune response to islets released from damaged capsules; and (4) reduction of the inflammatory response to the capsules/islets by improvements in the structure of the capsules and/or in genetic engineering of the pigs and/or in some form of drug therapy. Ethical and regulatory frameworks for islet xenotransplantation are already available in several countries, and there is now a wider international perception of the importance of developing an internationally harmonized ethical and regulatory framework.
Collapse
Affiliation(s)
- David K.C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shinichi Matsumoto
- Otsuka Pharmaceutical Factory, Tateiwa, Muya-cho, Naruto Tokushima, Japan
| | | | - Takeshi Itoh
- Department of Regenerative Medicine and Transplantation, Faculty of Medicine, Fukuoka University, Fukuoka City, Fukuoka, Japan
| | - Nizar I. Mourad
- Laboratory of Surgery and Transplantation, Catholic University of Louvain, Brussels, Belgium
| | - Pierre R Gianello
- Laboratory of Surgery and Transplantation, Catholic University of Louvain, Brussels, Belgium
| | - Eckhard Wolf
- Gene Center, LMU Munich and German Center for Diabetes Research (DZD), Munich, Germany
| | - Emanuele Cozzi
- Transplantation Immunology Unit, Padua University Hospital, and the Consortium for Research in Organ Transplantation (CORIT), Padua, Italy
| |
Collapse
|
144
|
Diehl R, Ferrara F, Müller C, Dreyer AY, McLeod DD, Fricke S, Boltze J. Immunosuppression for in vivo research: state-of-the-art protocols and experimental approaches. Cell Mol Immunol 2016; 14:146-179. [PMID: 27721455 PMCID: PMC5301156 DOI: 10.1038/cmi.2016.39] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 05/30/2016] [Accepted: 05/30/2016] [Indexed: 02/06/2023] Open
Abstract
Almost every experimental treatment strategy using non-autologous cell, tissue or organ transplantation is tested in small and large animal models before clinical translation. Because these strategies require immunosuppression in most cases, immunosuppressive protocols are a key element in transplantation experiments. However, standard immunosuppressive protocols are often applied without detailed knowledge regarding their efficacy within the particular experimental setting and in the chosen model species. Optimization of such protocols is pertinent to the translation of experimental results to human patients and thus warrants further investigation. This review summarizes current knowledge regarding immunosuppressive drug classes as well as their dosages and application regimens with consideration of species-specific drug metabolization and side effects. It also summarizes contemporary knowledge of novel immunomodulatory strategies, such as the use of mesenchymal stem cells or antibodies. Thus, this review is intended to serve as a state-of-the-art compendium for researchers to refine applied experimental immunosuppression and immunomodulation strategies to enhance the predictive value of preclinical transplantation studies.
Collapse
Affiliation(s)
- Rita Diehl
- Fraunhofer-Institute for Cell Therapy and Immunology, Leipzig 04103, Germany
| | - Fabienne Ferrara
- Fraunhofer-Institute for Cell Therapy and Immunology, Leipzig 04103, Germany.,Institute of Vegetative Physiology, Charite University Medicine and Center for Cardiovascular Research, Berlin 10115, Germany
| | - Claudia Müller
- Fraunhofer-Institute for Cell Therapy and Immunology, Leipzig 04103, Germany
| | - Antje Y Dreyer
- Fraunhofer-Institute for Cell Therapy and Immunology, Leipzig 04103, Germany
| | | | - Stephan Fricke
- Fraunhofer-Institute for Cell Therapy and Immunology, Leipzig 04103, Germany
| | - Johannes Boltze
- Fraunhofer-Institute for Cell Therapy and Immunology, Leipzig 04103, Germany.,Fraunhofer Research Institution for Marine Biotechnology and Institute for Medical and Marine Biotechnology, University of Lübeck, Lübeck 23562, Germany
| |
Collapse
|
145
|
|
146
|
Immunogenicity of Renal Microvascular Endothelial Cells From Genetically Modified Pigs. Transplantation 2016; 100:533-7. [PMID: 26906938 DOI: 10.1097/tp.0000000000001070] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Disrupting the porcine GGTA1 and CMAH genes [double knockout (DKO)] that produce the gal-α(1,3)-gal and N-glycolylneuraminic acid xenoantigens reduces human antibody binding to porcine peripheral blood mononuclear cells. It is important to examine rejection pathways at an organ-specific level. The object of this study is to evaluate the human preformed antibody reactivity against DKO renal microvascular endothelial cells (RMEC) in vitro. METHODS Characteristics of DKO RMEC were analyzed using flow cytometry. Human IgG/M binding to primary RMEC, immortalized RMEC (iRMEC), and iRMEC-deficient in B4GALNT2 genes were examined using flow cytometric crossmatch assay. RESULTS Porcine RMEC expressed gal-α(1,3)-gal, N-glycolylneuraminic acid, and Dolichos biflorus agglutinin glycans recognized by human preexisting antibodies in humans. Antigenicity of DKO RMEC was lower than GGTA1 KO RMEC. The disruption of B4GALNT2 gene in DKO iRMEC further reduced human IgG/IgM binding. CONCLUSIONS Silencing the porcine GGTA1, CMAH, and B4GALNT2 genes is an effective strategy to reduce human preformed antibody binding to RMEC. Porcine RMEC will be a useful reagent for the further study of xenoimmunology.
Collapse
|
147
|
Iwase H, Ekser B, Hara H, Ezzelarab MB, Long C, Thomson AW, Ayares D, Cooper DKC. Thyroid hormone: relevance to xenotransplantation. Xenotransplantation 2016; 23:293-9. [PMID: 27374212 DOI: 10.1111/xen.12243] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/23/2016] [Indexed: 12/01/2022]
Abstract
BACKGROUND It has been well documented that the level of serum/plasma free triiodothyronine (fT3) falls rapidly following brain death or during certain surgical procedures, for example, heart surgery carried out on cardiopulmonary bypass. The level in patients following cardiopulmonary bypass usually recovers within 2 days. METHODS We have measured serum fT3 in healthy naïve baboons (n = 31), healthy naïve monkeys (n = 5), and after pig-to-baboon heterotopic heart xenotransplantation (xenoTx) (Group 1, n = 9), orthotopic liver xenoTx (Group 2, n = 10), artery patch xenoTx (Group 3, n = 9), and in monkey-to-monkey heterotopic heart alloTx (Group 4, n = 5). RESULTS The mean level of fT3 in healthy naïve baboons was 3.1 ± 0.9 pg/ml and in healthy naïve monkeys was 2.6 ± 0.3 pg/ml. Following pig heart, liver, and artery patch xenoTx and monkey heart alloTx, there was an immediate rapid fall in fT3 level. Recovery of fT3 was more rapid in Groups 3 and 4 than in Groups 1 and 2. In Group 1, within 4 days fT3 had recovered, but only to the lower limit of normal range, where it remained throughout follow-up (for up to 42 days). In Group 2, no recovery was seen during the 7 days of follow-up. In immunosuppressed baboons with pig patch grafts that received IL-6R blockade (n = 2), the fT3 tended to rise higher than in those that received no IL-6R blockade (n = 6). CONCLUSIONS Following operative procedures, there is a dramatic fall in serum fT3 levels. The persistent low level of fT3 after pig heart and liver xenoTx may be associated with a continuing inflammatory state. We suggest that consideration should be given to the replacement of T3 therapy to maintain normal fT3 levels, particularly in nonhuman primates undergoing orthotopic pig heart or liver xenoTx.
Collapse
Affiliation(s)
- Hayato Iwase
- Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Burcin Ekser
- 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
| | - Cassandra Long
- Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Angus W Thomson
- 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
| |
Collapse
|
148
|
Affiliation(s)
- Ik Jin Yun
- Department of Surgery, Konkuk University School of Medicine, Seoul, Korea
| |
Collapse
|
149
|
Efficient production of multi-modified pigs for xenotransplantation by 'combineering', gene stacking and gene editing. Sci Rep 2016; 6:29081. [PMID: 27353424 PMCID: PMC4926246 DOI: 10.1038/srep29081] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 06/09/2016] [Indexed: 02/07/2023] Open
Abstract
Xenotransplantation from pigs could alleviate the shortage of human tissues and organs for transplantation. Means have been identified to overcome hyperacute rejection and acute vascular rejection mechanisms mounted by the recipient. The challenge is to combine multiple genetic modifications to enable normal animal breeding and meet the demand for transplants. We used two methods to colocate xenoprotective transgenes at one locus, sequential targeted transgene placement - ‘gene stacking’, and cointegration of multiple engineered large vectors - ‘combineering’, to generate pigs carrying modifications considered necessary to inhibit short to mid-term xenograft rejection. Pigs were generated by serial nuclear transfer and analysed at intermediate stages. Human complement inhibitors CD46, CD55 and CD59 were abundantly expressed in all tissues examined, human HO1 and human A20 were widely expressed. ZFN or CRISPR/Cas9 mediated homozygous GGTA1 and CMAH knockout abolished α-Gal and Neu5Gc epitopes. Cells from multi-transgenic piglets showed complete protection against human complement-mediated lysis, even before GGTA1 knockout. Blockade of endothelial activation reduced TNFα-induced E-selectin expression, IFNγ-induced MHC class-II upregulation and TNFα/cycloheximide caspase induction. Microbial analysis found no PERV-C, PCMV or 13 other infectious agents. These animals are a major advance towards clinical porcine xenotransplantation and demonstrate that livestock engineering has come of age.
Collapse
|
150
|
Abstract
The availability of cells, tissues and organs from a non-human species such as the pig could, at least in theory, meet the demand of organs necessary for clinical transplantation. At this stage, the important goal of getting over the first year of survival has been reported for both cellular and solid organ xenotransplantation in relevant preclinical primate models. In addition, xenotransplantation is already in the clinic as shown by the broad use of animal-derived medical devices, such as bioprosthetic heart valves and biological materials used for surgical tissue repair. At this stage, however, prior to starting a wide-scale clinical application of xenotransplantation of viable cells and organs, the important obstacle represented by the humoral immune response will need to be overcome. Likewise, the barriers posed by the activation of the innate immune system and coagulative pathway will have to be controlled. As far as xenogeneic nonviable xenografts, increasing evidence suggests that considerable immune reactions, mediated by both innate and adaptive immunity, take place and influence the long-term outcome of xenogeneic materials in patients, possibly precluding the use of bioprosthetic heart valves in young individuals. In this context, the present article provides an overview of current knowledge on the immune processes following xenotransplantation and on the possible therapeutic interventions to overcome the immunological drawbacks involved in xenotransplantation.
Collapse
Affiliation(s)
- M Vadori
- CORIT (Consortium for Research in Organ Transplantation), Via dell'Università 10, 35020 Legnaro, Padua, Italy
| | - E Cozzi
- CORIT (Consortium for Research in Organ Transplantation), Via dell'Università 10, 35020 Legnaro, Padua, Italy.,Transplant Immunology Unit, Department of Transfusion Medicine, Padua University Hospital, Via Giustiniani, 2, 35128 Padua, Italy
| |
Collapse
|