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Platt JL, Cascalho M, Piedrahita JA. Xenotransplantation: Progress Along Paths Uncertain from Models to Application. ILAR J 2019; 59:286-308. [PMID: 30541147 DOI: 10.1093/ilar/ily015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 08/23/2018] [Indexed: 12/18/2022] Open
Abstract
For more than a century, transplantation of tissues and organs from animals into man, xenotransplantation, has been viewed as a potential way to treat disease. Ironically, interest in xenotransplantation was fueled especially by successful application of allotransplantation, that is, transplantation of human tissue and organs, as a treatment for a variety of diseases, especially organ failure because scarcity of human tissues limited allotransplantation to a fraction of those who could benefit. In principle, use of animals such as pigs as a source of transplants would allow transplantation to exert a vastly greater impact than allotransplantation on medicine and public health. However, biological barriers to xenotransplantation, including immunity of the recipient, incompatibility of biological systems, and transmission of novel infectious agents, are believed to exceed the barriers to allotransplantation and presently to hinder clinical applications. One way potentially to address the barriers to xenotransplantation is by genetic engineering animal sources. The last 2 decades have brought progressive advances in approaches that can be applied to genetic modification of large animals. Application of these approaches to genetic engineering of pigs has contributed to dramatic improvement in the outcome of experimental xenografts in nonhuman primates and have encouraged the development of a new type of xenograft, a reverse xenograft, in which human stem cells are introduced into pigs under conditions that support differentiation and expansion into functional tissues and potentially organs. These advances make it appropriate to consider the potential limitation of genetic engineering and of current models for advancing the clinical applications of xenotransplantation and reverse xenotransplantation.
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Affiliation(s)
- Jeffrey L Platt
- Surgery, Microbiology & Immunology, and Transplantation Biology, University of Michigan, Ann Arbor, Michigan
| | - Marilia Cascalho
- Surgery, Microbiology & Immunology, and Transplantation Biology, University of Michigan, Ann Arbor, Michigan
| | - Jorge A Piedrahita
- Translational Medicine and The Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
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Kim H, Kim H, Lee SK, Jin XL, Kim TJ, Park C, Lee JI, Kim HS, Hong SK, Yoon KC, Ahn SW, Lee KB, Yi NJ, Yang J, Lee KW, Hawthorne WJ, Suh KS. Memory T cells are significantly increased in rejected liver allografts of rhesus monkeys. Liver Transpl 2018; 24:256-268. [PMID: 29150986 PMCID: PMC5817407 DOI: 10.1002/lt.24983] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 08/18/2017] [Accepted: 10/29/2017] [Indexed: 12/17/2022]
Abstract
The rhesus monkey (RM) is an excellent preclinical model in kidney, heart, and islet transplantation that has provided the basis for new immunosuppressive protocols for clinical studies. However, there remain relatively few liver transplantation (LT) models in nonhuman primates. In this study, we analyzed the immune cell populations of peripheral blood mononuclear cells (PBMCs) and secondary lymphoid organs along with livers of normal RMs and compared them with those of rejected LT recipients following withdrawal of immunosuppression. We undertook 5 allogeneic ABO compatible orthotopic LTs in monkeys using 5 normal donor monkey livers. We collected tissues including lymph nodes, spleens, blood, and recipient livers, and we performed flow cytometric analysis using isolated immune cells. We found that CD4 or CD8 naïve T cells were normally seen at low levels, and memory T cells were seen at high levels in the liver rather than lymphoid organs or PBMC. However, regulatory cells such as CD4+ forkhead box P3+ T cells and CD8+ CD28- cells remained in high numbers in the liver, but not in the lymph nodes or PBMC. The comparison of CD4/8 T subpopulations in normal and rejected livers and the various tissues showed that naïve cells were dramatically decreased in the spleen, lymph node, and PBMCs of rejected LT monkeys, but rather, the memory CD4/8 T cells were increased in all tissues and PBMC. The normal liver has large numbers of CD4 regulatory T cells, CD8+ CD28-, and myeloid-derived suppressor cells, which are known immunosuppressive cells occurring at much higher levels than those seen in lymph node or peripheral blood. Memory T cells are dramatically increased in rejected liver allografts of RMs compared with those seen in normal RM tissues. Liver Transplantation 24 256-268 2018 AASLD.
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Affiliation(s)
- Hwajung Kim
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Hyeyoung Kim
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Sun-Kyung Lee
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Xue-Li Jin
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Tae Jin Kim
- Division of Immunobiology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Chanho Park
- Division of Immunobiology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Jae-Il Lee
- Department of Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Hyo-Sin Kim
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Suk Kyun Hong
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyung Chul Yoon
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Sung Woo Ahn
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyoung-Bun Lee
- Department of Pathology, Seoul National University Hospital, Seoul, South Korea
| | - Nam-Joon Yi
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Jaeseok Yang
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea.,Transplantation Center, Seoul National University Hospital, Seoul, South Korea
| | - Kwang-Woong Lee
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Wayne J Hawthorne
- Department of Surgery, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Kyung-Suk Suh
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
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Abstract
Dysregulation of coagulation and disordered hemostasis are frequent complications in the pig-to-nonhuman primate preclinical xenotransplantation model. The most extreme manifestations are the systemic development of a life-threatening consumptive coagulopathy, characterized by thrombocytopenia and bleeding, which is balanced at the opposite extreme by local complications of graft loss due to thrombotic microangiopathy. The contributing mechanisms include inflammation, vascular injury, heightened innate, humoral and cellular immune responses, and molecular incompatibilities affecting the regulation of coagulation. There also appear to be organ-specific factors that have been linked to vascular heterogeneity. As examples, liver xenografts rapidly induce thrombocytopenia by sequestering human/primate platelets; renal xenografts cause a broader coagulopathy, linked in some cases to reactivation of porcine CMV, whereas cardiac xenografts often succumb to microvascular thrombosis without associated systemic coagulopathy but with local perturbations in fibrinolysis. Overcoming coagulation dysfunction will require a combination of genetic and pharmacological strategies. Deletion of the xenoantigen αGal, transgenic expression of human complement regulatory proteins, and refinement of immunosuppression to blunt the antibody response have all had some impact, without providing a complete solution. More recently, the addition of approaches specifically targeted at coagulation have produced promising results. As an example, heterotopic cardiac xenografts from donors expressing human thrombomodulin have survived for more than a year in immunosuppressed baboons, with no evidence of thrombotic microangiopathy or coagulopathy.
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Burlak C, Taylor RT. Xenotransplantation literature update, July-August 2014. Xenotransplantation 2014; 21:482-4. [PMID: 25250866 DOI: 10.1111/xen.12144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher Burlak
- Department of Surgery, Schultz Diabetes Institute, University of Minnesota, Minneapolis, MN, USA
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