1
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Habibabady ZA, Sendil S, Ellett F, Pollok F, Elias GF, French BM, Sun W, Braileanu G, Burdorf L, Irimia D, Pierson RN, Azimzadeh AM. Human erythrocyte fragmentation during ex-vivo pig organ perfusion. Xenotransplantation 2022; 29:e12729. [PMID: 35112383 PMCID: PMC8995366 DOI: 10.1111/xen.12729] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/22/2021] [Accepted: 01/10/2022] [Indexed: 01/25/2023]
Abstract
Platelet sequestration is a common process during organ reperfusion after transplantation. However, instead of lower platelet counts, when using traditional hemocytometers and light microscopy, we observed physiologically implausible platelet counts in the course of ex-vivo lung and liver xenograft organ perfusion studies. We employed conventional flow cytometry (FC) and imaging FC (AMINS ImageStream X) to investigate the findings and found platelet-sized fragments in the circulation that are mainly derived from red blood cell membranes. We speculate that this erythrocyte fragmentation contributes to anemia during in-vivo organ xenotransplant.
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Affiliation(s)
- Zahra A. Habibabady
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD,Center for Transplantation Sciences and Department of Surgery, Massachusetts General Hospital and Harvard School of Medicine, Boston, MA
| | - Selin Sendil
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD
| | - Felix Ellett
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard School of Medicine, and Shriners Burns Hospital, Boston, MA
| | - Franziska Pollok
- Center for Transplantation Sciences and Department of Surgery, Massachusetts General Hospital and Harvard School of Medicine, Boston, MA,Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Gabriela F. Elias
- Center for Transplantation Sciences and Department of Surgery, Massachusetts General Hospital and Harvard School of Medicine, Boston, MA
| | - Beth M. French
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD
| | - Wenji Sun
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD
| | - Gheorghe Braileanu
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD
| | - Lars Burdorf
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD,Center for Transplantation Sciences and Department of Surgery, Massachusetts General Hospital and Harvard School of Medicine, Boston, MA
| | - Daniel Irimia
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital, Harvard School of Medicine, and Shriners Burns Hospital, Boston, MA
| | - Richard N. Pierson
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD,Center for Transplantation Sciences and Department of Surgery, Massachusetts General Hospital and Harvard School of Medicine, Boston, MA
| | - Agnes M. Azimzadeh
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD,Center for Transplantation Sciences and Department of Surgery, Massachusetts General Hospital and Harvard School of Medicine, Boston, MA
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2
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Abstract
Experience with clinical liver xenotransplantation has largely involved the transplantation of livers from nonhuman primates. Experience with pig livers has been scarce. This brief review will be restricted to assessing the potential therapeutic impact of pig liver xenotransplantation in acute liver failure and the remaining barriers that currently do not justify clinical trials. A relatively new surgical technique of heterotopic pig liver xenotransplantation is described that might play a role in bridging a patient with acute liver failure until either the native liver recovers or a suitable liver allograft is obtained. Other topics discussed include the possible mechanisms for the development of the thrombocytopenis that rapidly occurs after pig liver xenotransplantation in a primate, the impact of pig complement on graft injury, the potential infectious risks, and potential physiologic incompatibilities between pig and human. There is cautious optimism that all of these problems can be overcome by judicious genetic manipulation of the pig. If liver graft survival could be achieved in the absence of thrombocytopenia or rejection for a period of even a few days, there may be a role for pig liver transplantation as a bridge to allotransplantation in carefully selected patients.
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3
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Zhou H, Liu H, Ezzelarab M, Schmelzer E, Wang Y, Gerlach J, Gridelli B, Cooper DKC. Experimental hepatocyte xenotransplantation--a comprehensive review of the literature. Xenotransplantation 2015; 22:239-48. [PMID: 25950141 PMCID: PMC4519403 DOI: 10.1111/xen.12170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/18/2015] [Indexed: 12/11/2022]
Abstract
Hepatocyte transplantation (Tx) is a potential therapy for certain diseases of the liver, including hepatic failure. However, there is a limited supply of human livers as a source of cells and, after isolation, human hepatocytes can be difficult to expand in culture, limiting the number available for Tx. Hepatocytes from other species, for example, the pig, have therefore emerged as a potential alternative source. We searched the literature through the end of 2014 to assess the current status of experimental research into hepatocyte xenoTx. The literature search identified 51 reports of in vivo cross-species Tx of hepatocytes in a variety of experimental models. Most studies investigated the Tx of human (n = 23) or pig (n = 19) hepatocytes. No studies explored hepatocytes from genetically engineered pigs. The spleen was the most common site of Tx (n = 23), followed by the liver (through the portal vein [n = 6]) and peritoneal cavity (n = 19). In 47 studies (92%), there was evidence of hepatocyte engraftment and function across a species barrier. The data provided by this literature search strengthen the hypothesis that xenoTx of hepatocytes is feasible and potentially successful as a clinical therapy for certain liver diseases, including hepatic failure. By excluding vascular structures, hepatocytes isolated from genetically engineered pig livers may address some of the immunological problems of xenoTx.
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Affiliation(s)
- Huidong Zhou
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Heng(1)yang, 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, ShanXi, China
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eva Schmelzer
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi Wang
- Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Heng(1)yang, Hunan, China
| | - Jörg Gerlach
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bruno Gridelli
- Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo, Italy
| | - David K. C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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4
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A human-specific mutation limits nonhuman primate efficacy in preclinical xenotransplantation studies. Transplantation 2014; 97:385-90. [PMID: 24445925 DOI: 10.1097/01.tp.0000441321.87915.82] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Patients diagnosed with fulminant hepatic failure face high mortality rates. A potential therapeutic approach for these patients is the use of extracorporeal porcine liver perfusion, to serve as a form of "liver dialysis." Previously, our laboratory has shown that, during a 72-hour extracorporeal perfusion with human blood, porcine Kupffer cells bind to and phagocytose human erythrocytes causing the hematocrit to fall to 2.5% of the original value. Subsequently, erythrocyte binding has been shown to involve N-acetylneuraminic acid (Neu5Ac) on the surface of human erythrocytes and sialoadhesin on the surface of the porcine Kupffer cells. METHODS Given that no primate other than the human is known to express the majority of its sialic acid as Neu5Ac, we evaluated whether nonhuman primates would provide adequate evaluation of the loss of erythrocytes that might be expected in a clinical trial of extracorporeal porcine liver perfusion. RESULTS We found that while porcine macrophages readily bound human erythrocytes, binding of nonhuman primate erythrocytes was significantly reduced (P<0.001). CONCLUSIONS This study suggests that nonhuman primates may fail to serve as an adequate model for studying extracorporeal porcine liver perfusion because of the fact that porcine macrophages do not bind nonhuman primate erythrocytes.
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5
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Waldman JP, Vogel T, Burlak C, Coussios C, Dominguez J, Friend P, Rees MA. Blocking porcine sialoadhesin improves extracorporeal porcine liver xenoperfusion with human blood. Xenotransplantation 2013; 20:239-51. [PMID: 23822217 PMCID: PMC4228799 DOI: 10.1111/xen.12043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/29/2013] [Indexed: 01/22/2023]
Abstract
BACKGROUND Patients in fulminant hepatic failure currently do not have a temporary means of support while awaiting liver transplantation. A potential therapeutic approach for such patients is the use of extracorporeal perfusion with porcine livers as a form of "liver dialysis". During a 72-h extracorporeal perfusion of porcine livers with human blood, porcine Kupffer cells bind to and phagocytose human red blood cells (hRBC) causing the hematocrit to decrease to 2.5% of the original value. Our laboratory has identified porcine sialoadhesin expressed on Kupffer cells as the lectin responsible for binding N-acetylneuraminic acid on the surface of the hRBC. We evaluated whether blocking porcine sialoadhesin prevents the recognition and subsequent destruction of hRBCs seen during extracorporeal porcine liver xenoperfusion. METHODS Ex vivo studies were performed using wild type pig livers perfused with isolated hRBCs for 72-h in the presence of an anti-porcine sialoadhesin antibody or isotype control. RESULTS The addition of an anti-porcine sialoadhesin antibody to an extracorporeal porcine liver xenoperfusion model reduces the loss of hRBC over a 72-h period. Sustained liver function was demonstrated throughout the perfusion. CONCLUSIONS This study illustrates the role of sialoadhesin in mediating the destruction of hRBCs in an extracorporeal porcine liver xenoperfusion model.
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Affiliation(s)
- Joshua P Waldman
- Department of Urology, University of Toledo Medical Center, Toledo, OH 43614, USA
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6
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Kim K, Schuetz C, Elias N, Veillette GR, Wamala I, Varma M, Smith RN, Robson SC, Cosimi AB, Sachs DH, Hertl M. Up to 9-day survival and control of thrombocytopenia following alpha1,3-galactosyl transferase knockout swine liver xenotransplantation in baboons. Xenotransplantation 2013; 19:256-64. [PMID: 22909139 DOI: 10.1111/j.1399-3089.2012.00717.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND With standard miniature swine donors, survivals of only 3 days have been achieved in primate liver-transplant recipients. The recent production of alpha1,3-galactosyl transferase knockout (GalT-KO) miniature swine has made it possible to evaluate xenotransplantation of pig organs in clinically relevant pig-to-non-human primate models in the absence of the effects of natural anti-Gal antibodies. We are reporting our results using GalT-KO liver grafts. METHODS We performed GalT-KO liver transplants in baboons using an immunosuppressive regimen previously used by our group in xeno heart and kidney transplantation. Post-operative liver function was assessed by laboratory function tests, coagulation parameters and histology. RESULTS In two hepatectomized recipients of GalT-KO grafts, post-transplant liver function returned rapidly to normal. Over the first few days, the synthetic products of the donor swine graft appeared to replace those of the baboon. The first recipient survived for 6 days and showed no histopathological evidence of rejection at the time of death from uncontrolled bleeding, probably caused by transfusion-refractory thrombocytopenia. Amicar treatment of the second and third recipients led to maintenance of platelet counts of over 40 000 per μl throughout their 9- and 8-day survivals, which represents the longest reported survival of pig-to-primate liver transplants to date. Both of the last two animals nevertheless succumbed to bleeding and enterococcal infection, without evidence of rejection. CONCLUSIONS These observations suggest that thrombocytopenia after liver xenotransplantation may be overcome by Amicar therapy. The coagulopathy and sepsis that nevertheless occurred suggest that additional causes of coagulation disturbance must be addressed, along with better prevention of infection, to achieve long-term survival.
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Affiliation(s)
- Karen Kim
- Department of Surgery, Massachusetts General Hospital, Boston, MA, USA
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7
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Brock LG, Delputte PL, Waldman JP, Nauwynck HJ, Rees MA. Porcine sialoadhesin: a newly identified xenogeneic innate immune receptor. Am J Transplant 2012; 12:3272-82. [PMID: 22958948 PMCID: PMC3513673 DOI: 10.1111/j.1600-6143.2012.04247.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Extracorporeal porcine liver perfusion is being developed as a bridge to liver allotransplantation for patients with fulminant hepatic failure. This strategy is limited by porcine Kupffer cell destruction of human erythrocytes, mediated by lectin binding of a sialic acid motif in the absence of antibody and complement. Sialoadhesin, a macrophage restricted lectin that binds sialic acid, was originally described as a sheep erythrocyte binding receptor. Given similarities between sialoadhesin and the unidentified macrophage lectin in our model, we hypothesized porcine sialoadhesin contributed to recognition of human erythrocytes. Two additional types of macrophages were identified to bind human erythrocytes-spleen and alveolar. Expression of sialoadhesin was confirmed by immunofluorescence in porcine tissues and by flow cytometry on primary macrophages. A stable transgenic cell line expressing porcine sialoadhesin (pSn CHO) bound human erythrocytes, while a sialoadhesin mutant cell line did not. Porcine macrophage and pSn CHO recognition of human erythrocytes was inhibited approximately 90% by an antiporcine sialoadhesin monoclonal antibody and by human erythrocyte glycoproteins. Furthermore, this binding was substantially reduced by sialidase treatment of erythrocytes. These data support the hypothesis that porcine sialoadhesin is a xenogeneic receptor that mediates porcine macrophage binding of human erythrocytes in a sialic acid-dependent manner.
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Affiliation(s)
- Linda G. Brock
- Department of Urology, University of Toledo Health Sciences Campus, Toledo, OH USA
| | - Peter L. Delputte
- Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Joshua P. Waldman
- Department of Urology, University of Toledo Health Sciences Campus, Toledo, OH USA
| | - Hans J. Nauwynck
- Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Michael A. Rees
- Department of Urology, University of Toledo Health Sciences Campus, Toledo, OH USA
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8
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Ekser B, Burlak C, Waldman JP, Lutz AJ, Paris LL, Veroux M, Robson SC, Rees MA, Ayares D, Gridelli B, Tector AJ, Cooper DKC. Immunobiology of liver xenotransplantation. Expert Rev Clin Immunol 2012; 8:621-34. [PMID: 23078060 PMCID: PMC3774271 DOI: 10.1586/eci.12.56] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pigs are currently the preferred species for future organ xenotransplantation. With advances in the development of genetically modified pigs, clinical xenotransplantation is becoming closer to reality. In preclinical studies (pig-to-nonhuman primate), the xenotransplantation of livers from pigs transgenic for human CD55 or from α1,3-galactosyltransferase gene-knockout pigs+/- transgenic for human CD46, is associated with survival of approximately 7-9 days. Although hepatic function, including coagulation, has proved to be satisfactory, the immediate development of thrombocytopenia is very limiting for pig liver xenotransplantation even as a 'bridge' to allotransplantation. Current studies are directed to understand the immunobiology of platelet activation, aggregation and phagocytosis, in particular the interaction between platelets and liver sinusoidal endothelial cells, hepatocytes and Kupffer cells, toward identifying interventions that may enable clinical application.
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Affiliation(s)
- Burcin Ekser
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
- Department of Surgery, Transplant Institute, Indiana University School of Medicine, Indiana University Health, Indianapolis, IN, USA
- Department of Surgery, Transplantation and Advanced Technologies, Vascular Surgery and Organ Transplant Unit, University Hospital of Catania, Catania, Italy
| | - Christopher Burlak
- Department of Surgery, Transplant Institute, Indiana University School of Medicine, Indiana University Health, Indianapolis, IN, USA
| | - Joshua P Waldman
- Department of Urology, University of Toledo Health Sciences Campus, Toledo, OH, USA
| | - Andrew J Lutz
- Department of Surgery, Transplant Institute, Indiana University School of Medicine, Indiana University Health, Indianapolis, IN, USA
| | - Leela L Paris
- Department of Surgery, Transplant Institute, Indiana University School of Medicine, Indiana University Health, Indianapolis, IN, USA
| | - Massimiliano Veroux
- Department of Surgery, Transplantation and Advanced Technologies, Vascular Surgery and Organ Transplant Unit, University Hospital of Catania, Catania, Italy
| | - Simon C Robson
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Michael A Rees
- Department of Urology, University of Toledo Health Sciences Campus, Toledo, OH, USA
| | | | - Bruno Gridelli
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
- Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo, Italy
| | - A Joseph Tector
- Department of Surgery, Transplant Institute, Indiana University School of Medicine, Indiana University Health, Indianapolis, IN, USA
| | - David KC Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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9
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Hara H, Campanile N, Tai HC, Long C, Ekser B, Yeh P, Welchons D, Ezzelarab M, Ayares D, Cooper DKC. An in vitro model of pig liver xenotransplantation--pig complement is associated with reduced lysis of wild-type and genetically modified pig cells. Xenotransplantation 2011; 17:370-8. [PMID: 20955293 DOI: 10.1111/j.1399-3089.2010.00602.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND After pig liver transplantation in humans, the graft will produce pig complement (C). We investigated in vitro the lysis of wild-type (WT), α1,3-galactosyltransferase gene-knockout (GTKO), and CD46 transgenic (CD46) pig peripheral blood mononuclear cells (PBMC) caused by human anti-pig antibodies (Abs) + pig C. METHODS Human serum IgM/IgG binding to WT and GTKO PBMC was determined by flow cytometry, and lysis of pig PBMC by a C-dependent cytotoxicity assay using (i) human serum (human Abs + C), (ii) GTKO pig serum (anti-Gal Abs + pig C), (iii) heat-inactivated human serum (human Abs) + rabbit C, or (iv) human Abs + pig C (serum). RESULTS Binding of human IgM and IgG to GTKO PBMC was less than to WT PBMC (P < 0.05). In the presence of human Abs, lysis of WT and GTKO PBMC by rabbit C was 87 and 13%, respectively (WT vs. GTKO, P < 0.01), but was only 37 and 0.4% in the presence of pig C (WT vs. GTKO, P < 0.05). Human/rabbit C-induced lysis was greater than pig C-induced lysis for both WT and GTKO PBMC. CD46 pig PBMC reduced rabbit/human C- and pig C-mediated lysis (P < 0.05). CONCLUSIONS Pig livers, particularly from GTKO and CD46 pigs, are likely to have an immunologic advantage over other organs after transplantation into humans. In the absence of pig antibodies directed to human tissues, pig complement is unlikely to cause problems after liver xenotransplantation, especially if GTKO/CD46 pigs are used as the source of the livers.
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Affiliation(s)
- Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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10
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Cooper DK, Hara H, Yazer M. Genetically Engineered Pigs as a Source for Clinical Red Blood Cell Transfusion. Clin Lab Med 2010; 30:365-80. [DOI: 10.1016/j.cll.2010.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Pierson RN, Dorling A, Ayares D, Rees MA, Seebach JD, Fishman JA, Hering BJ, Cooper DKC. Current status of xenotransplantation and prospects for clinical application. Xenotransplantation 2009; 16:263-80. [PMID: 19796067 PMCID: PMC2866107 DOI: 10.1111/j.1399-3089.2009.00534.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Xenotransplantation is one promising approach to bridge the gap between available human cells, tissues, and organs and the needs of patients with diabetes or end-stage organ failure. Based on recent progress using genetically modified source pigs, improving results with conventional and experimental immunosuppression, and expanded understanding of residual physiologic hurdles, xenotransplantation appears likely to be evaluated in clinical trials in the near future for some select applications. This review offers a comprehensive overview of known mechanisms of xenograft injury, a contemporary assessment of preclinical progress and residual barriers, and our opinions regarding where breakthroughs are likely to occur.
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Affiliation(s)
- Richard N Pierson
- Division of Cardiac Surgery, Department of Surgery, University of Maryland, Baltimore VAMC, Baltimore, MD 21201, USA.
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12
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Ekser B, Rigotti P, Gridelli B, Cooper DKC. Xenotransplantation of solid organs in the pig-to-primate model. Transpl Immunol 2008; 21:87-92. [PMID: 18955143 DOI: 10.1016/j.trim.2008.10.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Accepted: 10/09/2008] [Indexed: 12/12/2022]
Abstract
Xenotransplantation using pig organs could solve the significant increasing shortage of donor organs for allotransplantation. In the last two decades, major progress has been made in understanding the xenoimmunobiology of pig-to-nonhuman primate transplantation, and today we are close to clinical trials. The ability to genetically engineer pigs, such as human decay-accelerating factor (hDAF), CD46 (membrane cofactor protein), or alpha1,3-galactosyltransferase gene-knockout (GT-KO), has been a significant step toward the clinical application of xenotransplantation. Using GT-KO pigs and novel immunosuppressant agents, 2 to 6 months' survival of heterotopic heart xenotransplants has been achieved. In life-supporting kidney xenotransplantation, promising survival of close to 3 months has been achieved. However, liver and lung xenotransplantations do not have such encouraging survival as kidney and heart xenotransplantation. Although the introduction of hDAF and GT-KO pigs largely overcame hyperacute rejection, acute humoral xenograft rejection (AHXR) remains a challenge to be overcome if survival is to be increased. In several studies, when classical AHXR was prevented, thrombotic microangiopathy and coagulation dysregulation became more obvious, which make them another hurdle to be overcome. The initiating cause of failure of pig cardiac and renal xenografts may be antibody-mediated injury to the endothelium, leading to the development of microvascular thrombosis. Potential contributing factors toward the development of the thrombotic microangiopathy include: 1) the presence of preformed anti-non-Gal antibodies, 2) the development of very low levels of elicited antibodies to non-Gal antigens, 3) natural killer cell or macrophage activity, and 4) inherent coagulation dysregulation between pigs and primates. The breeding of pigs transgenic for an 'anticoagulant' or 'anti-thrombotic' gene, such as human tissue factor pathway inhibitor, hirudin, or CD39, or lacking the gene for the prothrombinase, fibrinogen-like protein-2, is anticipated to inhibit the change in the endothelium to a procoagulant state that takes place in the pig organ after transplantation. A further limitation for organ xenotransplantation is the potential for cross-species infection. As far as exogenous viruses are concerned, porcine cytomegalovirus has been detected in the tissues of recipient non-human primates, although no invasive disease was reported. Until today, no formal evidence has been presented from in vivo studies in non-human primates or from humans exposed to pig organs, tissues, or cells that porcine endogenous retroviruses infect primate cells. Xenotransplantation is a potential answer to the current organ shortage. Its future depends on; 1) further genetic modification of pigs, 2) the introduction of novel immunosuppressive agents that target the innate immune system and plasma cells, and 3) the development of clinically-applicable methods to induce donor-specific tolerance.
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Affiliation(s)
- Burcin Ekser
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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13
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Hara H, Gridelli B, Lin YJ, Marcos A, Cooper DKC. Liver xenografts for the treatment of acute liver failure: clinical and experimental experience and remaining immunologic barriers. Liver Transpl 2008; 14:425-34. [PMID: 18383106 DOI: 10.1002/lt.21476] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A critical element restricting the application of liver transplantation is the shortage of human deceased donor organs. Xenotransplantation using pig organs might be a solution to this shortage. Although the problems that still require resolution include the immunologic barrier, the potential risk of transferring infectious agents with the transplanted organ, and uncertainty about whether the transplanted organ will function satisfactorily in the human environment, recent progress in the genetic manipulation of pigs has led to the prospect that clinical xenografting, at least as a bridge to allotransplantation, may be possible in the foreseeable future. Experience with clinical auxiliary and orthotopic liver xenotransplantation and experimental liver xenotransplantation in nonhuman primate and other large animal models is reviewed, and the remaining immunologic problems are discussed. Evidence suggests that, in patients with hepatic failure, the pig liver may be less susceptible to antibody-mediated injury than other pig organs, such as the heart or kidney. Pig Kupffer cells and other macrophages will recognize and phagocytose primate red blood cells, but this problem should be overcome by pretransplant depletion of macrophages from the organ-source pig. From the evidence currently available, it does not seem unduly optimistic to anticipate that a liver from an alpha1,3-galactosyltransferase gene-knockout pig would survive at least long enough to function as a successful bridge to allotransplantation.
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Affiliation(s)
- Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
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14
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Li B, Allendorf DJ, Hansen R, Marroquin J, Cramer DE, Harris CL, Yan J. Combined yeast {beta}-glucan and antitumor monoclonal antibody therapy requires C5a-mediated neutrophil chemotaxis via regulation of decay-accelerating factor CD55. Cancer Res 2007; 67:7421-30. [PMID: 17671212 PMCID: PMC1933500 DOI: 10.1158/0008-5472.can-07-1465] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Administration of a combination of yeast-derived beta-glucan with antitumor monoclonal antibodies (mAb) has significant therapeutic efficacy in a variety of syngeneic murine tumor models. We have now tested this strategy using human carcinomas implanted in immunocompromised severe combined immunodeficient mice. Combined immunotherapy was therapeutically effective in vivo against NCI-H23 human non-small-cell lung carcinomas, but this modality was surprisingly ineffective against SKOV-3 human ovarian carcinomas. Whereas NCI-H23 tumors responded to this combination therapy with increased intratumoral neutrophil infiltration and C5a production, these responses were lacking in treated SKOV-3 tumors. Further results suggested that SKOV-3 tumors were protected by up-regulation of the membrane complement regulatory protein CD55 (decay-accelerating factor). Blockade of CD55 in vitro led to enhanced deposition of C activation product C3b and increased cytotoxicity mediated by beta-glucan-primed neutrophils. In vivo, administration of anti-CD55 mAb along with beta-glucan and anti-Her-2/neu mAb caused tumor regression and greatly improved long-term survival in animals bearing the previously resistant SKOV-3 tumors. This was accompanied by increased intratumoral neutrophil accumulation and C5a production. We conclude that CD55 suppresses tumor killing by antitumor mAb plus beta-glucan therapy (and, perhaps, in other circumstances). These results suggest a critical role for CD55 to regulate iC3b and C5a release and in turn to influence the recruitment of beta-glucan-primed neutrophils eliciting killing activity.
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MESH Headings
- Animals
- Antibodies, Monoclonal/therapeutic use
- CD55 Antigens/metabolism
- Carcinoma, Non-Small-Cell Lung/immunology
- Carcinoma, Non-Small-Cell Lung/pathology
- Carcinoma, Non-Small-Cell Lung/therapy
- Cell Line, Tumor
- Chemotaxis, Leukocyte/genetics
- Chemotaxis, Leukocyte/immunology
- Complement C3a/physiology
- Complement C5a/physiology
- Drug Therapy, Combination
- Female
- Humans
- Lung Neoplasms/immunology
- Lung Neoplasms/pathology
- Lung Neoplasms/therapy
- Mice
- Mice, Inbred ICR
- Mice, SCID
- Neutrophil Infiltration/genetics
- Neutrophil Infiltration/immunology
- Ovarian Neoplasms/immunology
- Ovarian Neoplasms/pathology
- Ovarian Neoplasms/therapy
- Saccharomyces cerevisiae/metabolism
- Tumor Cells, Cultured
- beta-Glucans/therapeutic use
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Affiliation(s)
- Bing Li
- Tumor Immunobiology Program of the James Graham Brown Cancer Center, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Daniel J. Allendorf
- Tumor Immunobiology Program of the James Graham Brown Cancer Center, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Richard Hansen
- Tumor Immunobiology Program of the James Graham Brown Cancer Center, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Jose Marroquin
- Tumor Immunobiology Program of the James Graham Brown Cancer Center, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Daniel E. Cramer
- Tumor Immunobiology Program of the James Graham Brown Cancer Center, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Claire L. Harris
- Complement Biology Group, Department of Medical Biochemistry and Immunology, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Jun Yan
- Tumor Immunobiology Program of the James Graham Brown Cancer Center, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
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15
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Cooper DKC, Dorling A, Pierson RN, Rees M, Seebach J, Yazer M, Ohdan H, Awwad M, Ayares D. Alpha1,3-galactosyltransferase gene-knockout pigs for xenotransplantation: where do we go from here? Transplantation 2007; 84:1-7. [PMID: 17627227 DOI: 10.1097/01.tp.0000260427.75804.f2] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The ability to genetically engineer pigs that no longer express the Galalpha1,3Gal (Gal) oligosaccharide has been a significant step toward the clinical applicability of xenotransplantation. Using a chronic immunosuppressive regimen based on costimulatory blockade, hearts from these pigs have survived from 2 to 6 months in baboons. Graft failure was predominantly from the development of a thrombotic microangiopathy. Potential contributing factors include the presence of preformed anti-nonGal antibodies or the development of low levels of elicited antibodies to nonGal antigens, natural killer (NK) cell or macrophage activity, and inherent coagulation dysregulation between pigs and primates. The breeding of pigs transgenic for an "anticoagulant" gene, such as human tissue factor pathway inhibitor, hirudin, or CD39, or lacking the gene for the prothrombinase, fibrinogen-like protein-2, is anticipated to inhibit the change in the endothelium to a procoagulant state that takes place in the pig organ after transplantation. The identification of the targets for anti-nonGal antibodies and/or human macrophages might allow further genetic modification of the pig, and xenogeneic NK cell recognition and activation may be inhibited by the transgenic expression of human leukocyte antigen molecules and/or by blocking the function of activating NK receptors. The ultimate goal of induction of T-cell tolerance may be possible only if these hurdles in the coagulation system and innate immunity can be overcome.
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Affiliation(s)
- David K C Cooper
- The Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
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16
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Abstract
The first blood transfusions in humans were xenotransfusions, carried out by Jean-Baptiste Denis beginning in 1667. Richard Lower, Matthäus Purmann and Georges Mercklin also experimented with the use of animal blood for transfusion until this practice was forbidden in 1670, after the death of one of Denis's patients. In the middle of the 19th century, xenotransfusion was rescued from oblivion by the work of Pierre Cyprien Oré. Franz Gesellius and Oscar Hasse fervently defended xenotransfusion, but Emil Ponfick and Leonard Landois stressed the potentially harmful effects of inter-species transfusion from 1874 onward. Xenotransfusion was abandoned completely following the discovery of blood groups by Karl Landsteiner in 1900. From 2000, because of progress in xenotransplantation and the need of blood supply, xenotransfusion is again being considered. Pigs are the best potential donors. The development of alpha-1,3-galactosyltransferase gene-knockout pigs has overcome the first hurdle to xenotransfusion. The main obstacle to porcine red blood cell transfusion is now the cellular response involving macrophages or natural killer cells.
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Affiliation(s)
- Françoise A Roux
- Department of Cellular and Molecular Immuno-Endocrinology, INRA, Nantes School of Veterinary Medicine, Nantes Cedex, France
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17
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Tai HC, Zhu X, Hara H, Lin YJ, Ezzelarab M, Long C, Ball S, Ayares D, Cooper DKC. The pig-to-primate immune response: relevance for xenotransplantation. Xenotransplantation 2007; 14:227-35. [PMID: 17489863 DOI: 10.1111/j.1399-3089.2007.00401.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The allotransplantation of some solid organs can be associated with a graft-vs.-host (GVH) response from the activity of donor B or T cells. We have investigated whether there is a risk of a GVH response following pig-to-primate organ xenotransplantation. METHODS The responses of 16 pigs (six farm-housed wild-type and five wild-type housed under high herd health conditions [all designated WT], and 5 alpha1,3-galactosyltransferase gene-knockout [GT-KO] housed under high herd health conditions) to human (n = 6) and baboon (n = 6) peripheral blood mononuclear cells (PBMC) were determined. Assays included flow cytometry, complement-dependent cytotoxicity, and mixed lymphocyte reaction. RESULTS Anti-primate cytotoxic IgM antibodies were detected in the sera of all pigs, but anti-primate IgG antibodies were minimal. All pigs demonstrated a cellular proliferative response to primate PBMC that was equivalent to, or greater than, the allo response. The strength of the pig-to-primate GVH responses was proportional to the health status of the pigs, those from a high health status herd, particularly from a specific pathogen-free herd maintained under clean husbandry conditions, where colonization of the gastrointestinal tract may be reduced, having lower responses. CONCLUSIONS After pig organ transplantation in a primate, if the organ is from an early-weaned, early-segregated GT-KO pig, the strength of a GVH response is likely to be relatively weak. Although not investigated here, any GVH response is likely to be suppressed by the immunosuppressive therapy administered to the recipient to suppress the anti-donor immune response.
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Affiliation(s)
- Hao-Chih Tai
- Department of Surgery, The Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
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18
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Ibrahim Z, Busch J, Awwad M, Wagner R, Wells K, Cooper DKC. Selected physiologic compatibilities and incompatibilities between human and porcine organ systems. Xenotransplantation 2006; 13:488-99. [PMID: 17059572 DOI: 10.1111/j.1399-3089.2006.00346.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The shortage of donor organs is a major barrier to clinical organ transplantation. Although xenotransplantation is considered one of the alternatives to human organ transplantation, there are immunologic and physiologic incompatibilities between humans and pigs. With the exception of coagulation, the major potential physiologic incompatibilities relating to function of the kidney, heart, liver, lungs, pancreatic islets, and hormones are reviewed. Some of these physiologic differences can be overcome by producing genetically altered pigs to improve compatibility with humans. The possibility of producing such pigs for organ transplantation is considered.
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Affiliation(s)
- Zuhaib Ibrahim
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
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19
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Burlak C, Twining LM, Rees MA. Terminal Sialic Acid Residues on Human Glycophorin A Are Recognized by Porcine Kupffer Cells. Transplantation 2005; 80:344-52. [PMID: 16082330 DOI: 10.1097/01.tp.0000162974.94890.9f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND We have previously shown that recognition of human erythrocytes by porcine Kupffer cells is mediated by a carbohydrate-dependent mechanism. The present study explores the possible ligands existing on human glycophorin A and tests their ability to inhibit erythrocyte rosette formation. METHODS Human erythrocytes were tested for ABO and MN specificity and used as targets in a 51Chromium quantitative erythrocyte rosette assay. Monosaccharides present on human glycophorin A, neuraminyl lactoses, bovine and porcine submaxillary mucins (BSM and PSM), and hyaluronic acid as well as proteoglycan N-linked glycosidase F(PNGaseF)- and sialidase A-treated human erythrocyte glycoproteins (hEGP) and human erythrocytes were all tested for inhibitory potential in the rosetting assay. RESULTS Porcine Kupffer-cell recognition of human erythrocytes was insensitive to differences in blood groups A, B, O, or MN. At 30 mM, the monosaccharide, N-acetylneuraminic acid, and the trisaccharide mixture, neuraminyl lactoses, disrupted human erythrocyte recognition by 25% and 30%, respectively. A dilution of BSM but not PSM inhibited the rosetting assay by 17% (.2 mg/mL), 33% (1 mg/mL), and 53% (2 mg/mL). The same dilution of hyaluronic acid had no effect on rosetting. Removal of N-linked oligosaccharides from hEGP with PNGaseF did not impair its ability to inhibit the rosetting assay. In contrast, removal of sialic acid completely abrogated its inhibitory ability. Treatment of whole human erythrocytes with sialidase A likewise prevented recognition by porcine Kupffer cells. CONCLUSIONS Terminal sialic acid on human erythrocytes is a target recognized by porcine Kupffer cells, suggesting a role for a sialic-acid receptor in innate cellular recognition of xenogeneic epitopes. Inasmuch as this work reveals a carbohydrate-recognition mechanism for cellular rejection, we shed light on a potential new boundary that will need to be overcome within xenotransplantation.
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