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Du Z, Chen C, Zheng Y, Wang X, Song C. Retroviral Insertion Polymorphism (RIP) of Porcine Endogenous Retroviruses (PERVs) in Pig Genomes. Animals (Basel) 2024; 14:621. [PMID: 38396589 PMCID: PMC10886097 DOI: 10.3390/ani14040621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/29/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Endogenous retroviruses (ERVs) are one of the superfamilies of long terminal repeat retrotransposons (LTRs) in mice and humans. Approximately 8% of the pig genome is composed of sequences derived from LTRs. While the majority of ERVs in pigs have decayed, a small number of full-length copies can still mobilize within the genome. This study investigated the unexplored retroviral insertion polymorphisms (RIPs) generated by the mobilization of full-length ERVs (Fl-ERVs), and evaluated their impact on phenotypic variation to gain insights into the biological role of Fl-ERVs in pigs. Overall, 39 RIPs (insertions or deletions relative to the pig reference genome) generated by Fl-ERVs were predicted by comparative genomic analysis, and 18 of them were confirmed by PCR detection. Four RIP sites (D5, D14, D15, and D18) were further evaluated by population analysis, and all of them displayed polymorphisms in multiple breeds. The RIP site of ERV-D14, which is a Fl-ERV inserted in the STAB2-like gene, was further confirmed by sequencing. Population analysis of the polymorphic site of ERV-D14 reveals that it presents moderate polymorphism information in the Large White pig breed, and the association analysis reveals that the RIP of ERV-D14 is associated with age variations at 30 kg body weight (p < 0.05) and 100 kg body weight (p < 0.01) in the population of Large White pigs (N = 480). Furthermore, the ERV-D14 RIP is associated with changes in the expression of the target gene STAB2-like in the liver, backfat, and leaf fat in Sushan pigs. These data suggest that some Fl-ERVs are still mobilizing in the pig's genome, and contribute to genomic and phenotypic variations.
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Affiliation(s)
- Zhanyu Du
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China; (Z.D.); (C.C.); (Y.Z.); (X.W.)
- College of Grassland Resources, Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu 610225, China
| | - Cai Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China; (Z.D.); (C.C.); (Y.Z.); (X.W.)
| | - Yao Zheng
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China; (Z.D.); (C.C.); (Y.Z.); (X.W.)
| | - Xiaoyan Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China; (Z.D.); (C.C.); (Y.Z.); (X.W.)
| | - Chengyi Song
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China; (Z.D.); (C.C.); (Y.Z.); (X.W.)
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2
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Wadiwala IJ, Garg P, Yazji JH, Alamouti-fard E, Alomari M, Hussain MWA, Elawady MS, Jacob S. Evolution of Xenotransplantation as an Alternative to Shortage of Donors in Heart Transplantation. Cureus 2022; 14:e26284. [PMID: 35754438 PMCID: PMC9230910 DOI: 10.7759/cureus.26284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2022] [Indexed: 12/03/2022] Open
Abstract
This review aims to show and illustrate the history, current, ethical considerations, and limitations concerning xenotransplantation. Due to the current shortage of available donor organs for transplantation, many alternative sources are being examined to solve the donor shortage. One of them is xenotransplantation which refers to the transplantation of organs from one species to another. Compared to other nonhuman primates (NHP), pigs are ideal species for organ harvesting as they rapidly grow to human size in a handful of months. There is much advancement in the genetic engineering of pigs, which have hearts structurally and functionally similar to the human heart. The role of genetic engineering is to overcome the immune barriers in xenotransplantation and can be used in hyperacute rejection and T cell-mediated rejection. It is technically difficult to use large animal models for orthotopic, life-sustaining heart transplantation. Despite the fact that some religious traditions, such as Jewish and Muslim, prohibit the ingestion of pork products, few religious leaders consider that donating porcine organs is ethical because it saves human life. Although recent technologies have lowered the risk of a xenograft producing a novel virus that causes an epidemic, the risk still exists. It has major implications for the informed consent procedure connected with clinical research on heart xenotransplantation.
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Chen J, Zhong J, He X, Li X, Ni P, Safner T, Šprem N, Han J. The de novo assembly of a European wild boar genome revealed unique patterns of chromosomal structural variations and segmental duplications. Anim Genet 2022; 53:281-292. [PMID: 35238061 PMCID: PMC9314987 DOI: 10.1111/age.13181] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/12/2022] [Accepted: 02/12/2022] [Indexed: 02/05/2023]
Abstract
The rapid progress of sequencing technology has greatly facilitated the de novo genome assembly of pig breeds. However, the assembly of the wild boar genome is still lacking, hampering our understanding of chromosomal and genomic evolution during domestication from wild boars into domestic pigs. Here, we sequenced and de novo assembled a European wild boar genome (ASM2165605v1) using the long‐range information provided by 10× Linked‐Reads sequencing. We achieved a high‐quality assembly with contig N50 of 26.09 Mb. Additionally, 1.64% of the contigs (222) with lengths from 107.65 kb to 75.36 Mb covered 90.3% of the total genome size of ASM2165605v1 (~2.5 Gb). Mapping analysis revealed that the contigs can fill 24.73% (93/376) of the gaps present in the orthologous regions of the updated pig reference genome (Sscrofa11.1). We further improved the contigs into chromosome level with a reference‐assistant scaffolding method. Using the ‘assembly‐to‐assembly’ approach, we identified intra‐chromosomal large structural variations (SVs, length >1 kb) between ASM2165605v1 and Sscrofa11.1 assemblies. Interestingly, we found that the number of SV events on the X chromosome deviated significantly from the linear models fitting autosomes (R2 > 0.64, p < 0.001). Specifically, deletions and insertions were deficient on the X chromosome by 66.14 and 58.41% respectively, whereas duplications and inversions were excessive on the X chromosome by 71.96 and 107.61% respectively. We further used the large segmental duplications (SDs, >1 kb) events as a proxy to understand the large‐scale inter‐chromosomal evolution, by resolving parental‐derived relationships for SD pairs. We revealed a significant excess of SD movements from the X chromosome to autosomes (p < 0.001), consistent with the expectation of meiotic sex chromosome inactivation. Enrichment analyses indicated that the genes within derived SD copies on autosomes were significantly related to biological processes involving nervous system, lipid biosynthesis and sperm motility (p < 0.01). Together, our analyses of the de novo assembly of ASM2165605v1 provides insight into the SVs between European wild boar and domestic pig, in addition to the ongoing process of meiotic sex chromosome inactivation in driving inter‐chromosomal interaction between the sex chromosome and autosomes.
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Affiliation(s)
- Jianhai Chen
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Jie Zhong
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Xuefei He
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoyu Li
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Pan Ni
- Animal Husbandry and Veterinary Institute of Keqiao District, Shaoxing, Zhejiang, China
| | - Toni Safner
- Faculty of Agriculture, University of Zagreb, Zagreb, Croatia.,Centre of Excellence for Biodiversity and Molecular Plant Breeding, (CoE CroP-BioDiv), Zagreb, Croatia
| | - Nikica Šprem
- Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
| | - Jianlin Han
- International Livestock Research Institute, Nairobi, Kenya.,CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
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4
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Denner J. Porcine Endogenous Retroviruses and Xenotransplantation, 2021. Viruses 2021; 13:v13112156. [PMID: 34834962 PMCID: PMC8625113 DOI: 10.3390/v13112156] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/06/2021] [Accepted: 10/20/2021] [Indexed: 12/25/2022] Open
Abstract
Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pigs, and some of them are able to infect human cells. Therefore, PERVs pose a risk for xenotransplantation, the transplantation of pig cells, tissues, or organ to humans in order to alleviate the shortage of human donor organs. Up to 2021, a huge body of knowledge about PERVs has been accumulated regarding their biology, including replication, recombination, origin, host range, and immunosuppressive properties. Until now, no PERV transmission has been observed in clinical trials transplanting pig islet cells into diabetic humans, in preclinical trials transplanting pig cells and organs into nonhuman primates with remarkable long survival times of the transplant, and in infection experiments with several animal species. Nevertheless, in order to prevent virus transmission to the recipient, numerous strategies have been developed, including selection of PERV-C-free animals, RNA interference, antiviral drugs, vaccination, and genome editing. Furthermore, at present there are no more experimental approaches to evaluate the full risk until we move to the clinic.
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Affiliation(s)
- Joachim Denner
- Department of Veterinary Medicine, Institute of Virology, Free University Berlin, 14163 Berlin, Germany
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CRISPR/Cas Technology in Pig-to-Human Xenotransplantation Research. Int J Mol Sci 2021; 22:ijms22063196. [PMID: 33801123 PMCID: PMC8004187 DOI: 10.3390/ijms22063196] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
CRISPR/Cas (clustered regularly interspaced short palindromic repeats linked to Cas nuclease) technology has revolutionized many aspects of genetic engineering research. Thanks to it, it became possible to study the functions and mechanisms of biology with greater precision, as well as to obtain genetically modified organisms, both prokaryotic and eukaryotic. The changes introduced by the CRISPR/Cas system are based on the repair paths of the single or double strand DNA breaks that cause insertions, deletions, or precise integrations of donor DNA. These changes are crucial for many fields of science, one of which is the use of animals (pigs) as a reservoir of tissues and organs for xenotransplantation into humans. Non-genetically modified animals cannot be used to save human life and health due to acute immunological reactions resulting from the phylogenetic distance of these two species. This review is intended to collect and summarize the advantages as well as achievements of the CRISPR/Cas system in pig-to-human xenotransplantation research. In addition, it demonstrates barriers and limitations that require careful evaluation before attempting to experiment with this technology.
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Lu T, Yang B, Wang R, Qin C. Xenotransplantation: Current Status in Preclinical Research. Front Immunol 2020; 10:3060. [PMID: 32038617 PMCID: PMC6989439 DOI: 10.3389/fimmu.2019.03060] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/16/2019] [Indexed: 12/13/2022] Open
Abstract
The increasing life expectancy of humans has led to a growing numbers of patients with chronic diseases and end-stage organ failure. Transplantation is an effective approach for the treatment of end-stage organ failure; however, the imbalance between organ supply and the demand for human organs is a bottleneck for clinical transplantation. Therefore, xenotransplantation might be a promising alternative approach to bridge the gap between the supply and demand of organs, tissues, and cells; however, immunological barriers are limiting factors in clinical xenotransplantation. Thanks to advances in gene-editing tools and immunosuppressive therapy as well as the prolonged xenograft survival time in pig-to-non-human primate models, clinical xenotransplantation has become more viable. In this review, we focus on the evolution and current status of xenotransplantation research, including our current understanding of the immunological mechanisms involved in xenograft rejection, genetically modified pigs used for xenotransplantation, and progress that has been made in developing pig-to-pig-to-non-human primate models. Three main types of rejection can occur after xenotransplantation, which we discuss in detail: (1) hyperacute xenograft rejection, (2) acute humoral xenograft rejection, and (3) acute cellular rejection. Furthermore, in studies on immunological rejection, genetically modified pigs have been generated to bridge cross-species molecular incompatibilities; in the last decade, most advances made in the field of xenotransplantation have resulted from the production of genetically engineered pigs; accordingly, we summarize the genetically modified pigs that are currently available for xenotransplantation. Next, we summarize the longest survival time of solid organs in preclinical models in recent years, including heart, liver, kidney, and lung xenotransplantation. Overall, we conclude that recent achievements and the accumulation of experience in xenotransplantation mean that the first-in-human clinical trial could be possible in the near future. Furthermore, we hope that xenotransplantation and various approaches will be able to collectively solve the problem of human organ shortage.
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Affiliation(s)
- Tianyu Lu
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Bochao Yang
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Ruolin Wang
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Chuan Qin
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
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7
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Chung HC, Nguyen VG, Moon HJ, Park YH, Park BK. Regulation of porcine endogenous retrovirus by dual LTR1+2 (Long Terminal Region) miRNA in primary porcine kidney cells. J Vet Sci 2020; 20:e50. [PMID: 31565893 PMCID: PMC6769330 DOI: 10.4142/jvs.2019.20.e50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/18/2019] [Accepted: 08/05/2019] [Indexed: 11/20/2022] Open
Abstract
Porcine endogenous retroviruses (PERVs) integrate into germline DNA as proviral genome that enables vertical transmission from parents to their offspring. The provirus usually survives as part of the host genome rather than as an infectious agent, but may become pathogenic if it crosses species barriers. Therefore, replication-competent PERV should be controlled through selective breeding or knockout technologies. Two microRNAs (miRNAs), dual LTR1 and LTR2, were selected to inhibit the expression of PERV in primary porcine kidney cells. The inhibition efficiency of the miRNAs was compared based on their inhibition of different PERV regions, specifically long terminal repeats (LTRs), gag, pol, and env. Gene expression was quantified using real-time polymerase chain reaction and the C-type reverse transcriptase (RT) activity was determined. The messenger RNA (mRNA) expression of the PERV LTR and env regions was determined in HeLa cells co-cultured with primary porcine kidney cells. The mRNA expression of the LTR, gag, pol, and env regions of PERV was dramatically inhibited by dual miRNA from 24 to 144 h after transfection, with the highest inhibition observed for the LTR and pol regions at 120 h. Additionally, the RT activity of PERV in the co-culture experiment of porcine and human cells was reduced by 84.4% at the sixth passage. The dual LTR 1+2 miRNA efficiently silences PERV in primary porcine kidney cells.
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Affiliation(s)
- Hee Chun Chung
- Department of Veterinary Medicine Virology Lab, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Van Giap Nguyen
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam
| | - Hyung Joon Moon
- Research Unit, Green Cross Veterinary Products, Yongin 17066, Korea
| | - Yong Ho Park
- Department of Veterinary Microbiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Bong Kyun Park
- Department of Veterinary Medicine Virology Lab, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
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Smood B, Hara H, Schoel LJ, Cooper DKC. Genetically-engineered pigs as sources for clinical red blood cell transfusion: What pathobiological barriers need to be overcome? Blood Rev 2019; 35:7-17. [PMID: 30711308 DOI: 10.1016/j.blre.2019.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/02/2019] [Accepted: 01/25/2019] [Indexed: 12/27/2022]
Abstract
An alternative to human red blood cells (RBCs) for clinical transfusion would be advantageous, particularly in situations of massive acute blood loss (where availability and compatibility are limited) or chronic hematologic diseases requiring frequent transfusions (resulting in alloimmunization). Ideally, any alternative must be neither immunogenic nor pathogenic, but readily available, inexpensive, and physiologically effective. Pig RBCs (pRBCs) provide a promising alternative due to their several similarities with human RBCs, and our increasing ability to genetically-modify pigs to reduce cellular immunogenicity. We briefly summarize the history of xenotransfusion, the progress that has been made in recent years, and the remaining barriers. These barriers include prevention of (i) human natural antibody binding to pRBCs, (ii) their phagocytosis by macrophages, and (iii) the T cell adaptive immune response (in the absence of exogenous immunosuppressive therapy). Although techniques of genetic engineering have advanced in recent years, novel methods to introduce human transgenes into pRBCs (which do not have nuclei) will need to be developed before clinical trials can be initiated.
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Affiliation(s)
- Benjamin Smood
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Leah J Schoel
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
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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.
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Chung HC, Nguyen VG, Oh WT, Huynh TML, Moon HJ, Lee JH, Kim HK, Park SJ, Park BK. Inhibition of Porcine Endogenous Retrovirus by Multi-Targeting Micro RNA Against Long Terminal Region. Transplant Proc 2018; 49:2225-2232. [PMID: 29149987 DOI: 10.1016/j.transproceed.2017.09.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/21/2017] [Accepted: 09/02/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND There might be much benefit in xenotransplantation, however, the risk of infections across species barriers remains, especially porcine endogenous retrovirus (PERV). To date, many attempts have been made to knock down active PERVs by inhibitory RNA (RNAi) and micro RNA (miRNA), which target different genes of PERV. There are a few studies that have explored whether targeting promoter regions of PERV could exert an inhibition effect. METHODS miRNAs were automatically selected based on an online program BLOCK-iT RNAi Designer. The inhibition efficiency between miRNAs was compared based on their inhibition of different PERV genes: long terminal repeats (LTR), gag, and pol. Both relative quantitative real-time polymerase chain reaction (PCR) and C-type reverse transcriptase activity were performed. RESULTS The results demonstrated that miRNA targeting the LTR region degraded the target sequence, and simultaneously inhibited the mRNA expression of both gag and pol genes of PERV. The LTR1, LTR2, and dual LTR1 + LTR2 miRNA inhibited 76.2%, 22%, and 76.8% of gag gene expression, respectively. Similarly, the miRNA was found to knock down the pol gene expression of 69.8%, 25.5%, and 77.7% for single targeting miRNA (LTR1 and LTR2) and multi-targeting miRNA (LTR1 + LTR2), respectively. A stable PK15 clone constitutively expressed dual LTR1 + LTR2 miRNA and exhibited higher inhibitory up to 82.8% and 92.7% of the expressions of the gag and pol genes, respectively. Also, the result of co-cultivation of dual LTR1 + LTR2 miRNA transfected PK15 cell with a human cell line inhibited expression of LTR, gag, and pol genes of PERV. CONCLUSIONS In conclusion, this study suggested that the LTR might be an alternative target for gene silencing of PERV, and that multi-targeting miRNA had better inhibitory effect than single- targeting miRNA. In an in vitro model, the presence of miRNA was able to reduce PERV infectivity in a human cell line.
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Affiliation(s)
- H-C Chung
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - V-G Nguyen
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - W-T Oh
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - T-M-L Huynh
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - H-J Moon
- Research Unit, Green Cross Veterinary Products, Yongin, Republic of Korea
| | - J-H Lee
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - H-K Kim
- Viral Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - S-J Park
- Forensic Medicine Division, Daegu Institute, National Forensic Service, Chilgok, Korea
| | - B-K Park
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea.
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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.
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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
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12
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Kim N, Choi J, Kim S, Gwon YD, Cho Y, Yang JM, Oh YK, Kim YB. Transmission of Porcine Endogenous Retrovirus Produced from Different Recipient Cells In Vivo. PLoS One 2016; 11:e0165156. [PMID: 27832080 PMCID: PMC5104465 DOI: 10.1371/journal.pone.0165156] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/29/2016] [Indexed: 12/04/2022] Open
Abstract
Humanized pigs have been developed to reduce the incidence of immune rejection in xenotransplantation, but significant concerns remain, such as transmission of viral zoonosis. Porcine endogenous retroviruses (PERV), which exist in the genome of pigs, are produced as infectious virions from all porcine cells and cause zoonosis. Here, we examined the possibility of zoonosis of hosts under conditions of immune suppression or xenotransplantation of cells producing host-adapted viruses. Upon transplantation of PERV-producing porcine cells into mice, no transmission of PERV was detected, whereas, transmission of PERV from mice transplanted with mouse-adapted PERV-producing cells was detected. In addition, the frequency of PERV transmission was increased in CsA treated mice transplanted with PERV-producing murine cells, compared with PERV-producing porcine cells. Transmission of PERV to host animals did not affect weight but immune responses, in particular, the number of T cells from PERV-transmitted mice, were notably reduced. The observed risk of PERV zoonosis highlights the requirement for thorough evaluation of viral zoonosis under particular host conditions, such as immunosuppressive treatment and transplantation with host-adapted virus-producing cells.
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Affiliation(s)
- Nayoung Kim
- Department of Life Sciences, Sogang University, Seoul, Republic of Korea
| | - Jiwon Choi
- Department of Bio-industrial Technologies, Konkuk University, Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea
| | - Sehyun Kim
- Department of Bio-industrial Technologies, Konkuk University, Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea
| | - Yong-Dae Gwon
- Department of Bio-industrial Technologies, Konkuk University, Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea
| | - Yeondong Cho
- Department of Bio-industrial Technologies, Konkuk University, Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea
| | - Jae Myung Yang
- Department of Life Sciences, Sogang University, Seoul, Republic of Korea
| | - Yu-Kyoung Oh
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Young bong Kim
- Department of Bio-industrial Technologies, Konkuk University, Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea
- * E-mail:
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Jung WY, Yu SL, Seo DW, Jung KC, Cho IC, Lim HT, Jin DI, Lee JH. Characterization of insertional variation of porcine endogenous retroviruses in six different pig breeds. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2014; 25:1357-63. [PMID: 25049490 PMCID: PMC4093020 DOI: 10.5713/ajas.2012.12131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 07/11/2012] [Accepted: 05/01/2012] [Indexed: 11/27/2022]
Abstract
Pigs may need to be exploited as xenotransplantation donors due to the shortage of human organs, tissues and cells. Porcine endogenous retroviruses (PERVs) are a significant obstacle to xenotransplantation because they can infect human cells in vitro and have the potential for transmission of unexpected pathogens to humans. In this research, 101 pigs, including four commercial breeds (23 Berkshire, 13 Duroc, 22 Landrace and 14 Yorkshire pigs), one native breed (19 Korean native pigs) and one miniature breed (10 NIH miniature pigs) were used to investigate insertional variations for 11 PERV loci (three PERV-A, six PERV-B and two PERV-C). Over 60% of the pigs harbored one PERV-A (907F8) integration and five PERV-B (B3-3G, B3-7G, 742H1, 1155D9 and 465D1) integrations. However, two PERV-A loci (A1-6C and 1347C1) and one PERV-B locus (B3-7F) were absent in Duroc pigs. Moreover, two PERV-C loci (C2-6C and C4-2G) only existed in Korean native pigs and NIH miniature pigs. The results suggest that PERV insertional variations differ among pig breeds as well as among individuals within a breed. Also, the results presented here can be used for the selection of animals that do not have specific PERV integration for xenotransplantation research.
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Affiliation(s)
- W Y Jung
- National Agricultural Products Quality Management Service, Gyungki 430-824, Korea
| | - S L Yu
- National Agricultural Products Quality Management Service, Gyungki 430-824, Korea
| | - D W Seo
- National Agricultural Products Quality Management Service, Gyungki 430-824, Korea
| | - K C Jung
- National Agricultural Products Quality Management Service, Gyungki 430-824, Korea
| | - I C Cho
- National Institute of Animal Science, Jeju 690-150, Korea
| | - H T Lim
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - D I Jin
- National Agricultural Products Quality Management Service, Gyungki 430-824, Korea
| | - J H Lee
- National Agricultural Products Quality Management Service, Gyungki 430-824, Korea
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Luo Y, Lin L, Bolund L, Jensen TG, Sørensen CB. Genetically modified pigs for biomedical research. J Inherit Metab Dis 2012; 35:695-713. [PMID: 22453682 DOI: 10.1007/s10545-012-9475-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/09/2012] [Accepted: 03/02/2012] [Indexed: 01/17/2023]
Abstract
During the last two decades, pigs have been used to develop some of the most important large animal models for biomedical research. Advances in pig genome research, genetic modification (GM) of primary pig cells and pig cloning by nuclear transfer, have facilitated the generation of GM pigs for xenotransplantation and various human diseases. This review summarizes the key technologies used for generating GM pigs, including pronuclear microinjection, sperm-mediated gene transfer, somatic cell nuclear transfer by traditional cloning, and somatic cell nuclear transfer by handmade cloning. Broadly used genetic engineering tools for porcine cells are also discussed. We also summarize the GM pig models that have been generated for xenotransplantation and human disease processes, including neurodegenerative diseases, cardiovascular diseases, eye diseases, bone diseases, cancers and epidermal skin diseases, diabetes mellitus, cystic fibrosis, and inherited metabolic diseases. Thus, this review provides an overview of the progress in GM pig research over the last two decades and perspectives for future development.
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Affiliation(s)
- Yonglun Luo
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark.
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Nakaya Y, Shimode S, Kobayashi T, Imakawa K, Miyazawa T. Binding of transcription factor activating protein 2 γ on the 5'-proximal promoter region of human porcine endogenous retrovirus subgroup A receptor 2/GPR172B. Xenotransplantation 2012; 19:177-85. [PMID: 22702469 DOI: 10.1111/j.1399-3089.2012.00701.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Xenotransplantation is one of the solutions for the shortage of organ donors, and pigs have been considered to be the most suitable animal donors. Specific pathogen-free pigs are utilized in the xenotransplantation; however, pigs have infectious gammaretroviruses, named porcine endogenous retroviruses (PERVs) in their genome. Of them, PERV-A and PERV-B can infect human cells in vitro and potentially induce diseases like other gammaretroviruses. The human cellular receptors for PERV-A were identified and named human PERV-A receptor (HuPAR)-1 and HuPAR-2 (also called as GPR172A and GPR172B, respectively). We have recently reported that HuPAR-2 expression was regulated by epigenetic modification and preferentially expressed in placenta. However, the detailed mechanisms of HuPAR-2 expression have not been fully characterized. In this study, we analyzed molecular mechanisms associated with HuPAR-2 transcription through the identification of transcription factors that bind to the promoter region of HuPAR-2. METHODS In situ hybridization was performed to identify the cells expressing HuPAR-2 in placental tissues. Transcriptional activities were measured by dual-luciferase reporter assay using serial deletion mutants of HuPAR-2 5'-flanking region. To identify the transcription factors bound to the promoter region, in silico analysis, electrophoresis mobility shift assay, and chromatin immunoprecipitation assay were conducted. The effect of the transcription factor transcription factor activator protein (TFAP)-2γ on the promoter activities was investigated by overexpression of the factor. RESULTS We identified that HuPAR-2 was specifically expressed in villous trophoblast cells. We also identified that a region spanning from -126 to -32 had proximal promoter activities and TFAP-2γ bound to a region spanning from -58 to -35 in vitro and in vivo. The overexpression of TFAP-2γ also augmented the proximal promoter activity. CONCLUSION We demonstrated that TFAP-2γ is one of the transcription factors involved in the HuPAR-2 expression in human villous trophoblast cells. By studying transcriptional factors involved in the expression of HuPAR-2, we may find a clue to control the potential risks caused by PERV-A infection in xenotransplantation.
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Affiliation(s)
- Yuki Nakaya
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, Sakyo-ku, Kyoto, Japan
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Characterization of porcine endogenous retrovirus clones from the NIH miniature pig BAC library. J Biomed Biotechnol 2011; 2012:482568. [PMID: 21912484 PMCID: PMC3168785 DOI: 10.1155/2012/482568] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/08/2011] [Accepted: 06/16/2011] [Indexed: 02/03/2023] Open
Abstract
Pigs have been considered as donors for xenotransplantation in the replacement of human organs and tissues. However, porcine endogenous retroviruses (PERVs) might transmit new infectious disease to humans during xenotransplantation. To investigate PERV integration sites, 45 PERV-positive BAC clones, including 12 PERV-A, 16 PERV-B, and 17 PERV-C clones, were identified from the NIH miniature pig BAC library. The analysis of 12 selected full-length sequences of PERVs, including the long terminal repeat (LTR) region, identified the expected of open reading frame length, an indicative of active PERV, in all five PERV-C clones and one of the four PERV-B clones. Premature stop codons were observed in only three PERV-A clones. Also, eleven PERV integration sites were mapped using a 5000-rad IMpRH panel. The map locations of PERV-C clones have not been reported before, thus they are novel PERV clones identified in this study. The results could provide basic information for the elimination of site-specific PERVs in selection of pigs for xenotransplantation.
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Groth CG. The potential advantages of transplanting organs from pig to man: A transplant Surgeon's view. Indian J Urol 2011; 23:305-9. [PMID: 19718335 PMCID: PMC2721611 DOI: 10.4103/0970-1591.33729] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Once pig organs can be transplanted into humans, transplantation will move into a new era. There will be unlimited access to undamaged organs and cells for transplantation and, eventually, donation from deceased or live human beings will become obsolete. Furthermore, it will be possible to alleviate graft rejection, at least in part, by genetic modification of the source animal. Currently, there are three major obstacles to performing transplantations from pig to man: 1) a powerful immune barrier, 2) a potential risk of transmitting microorganisms, particularly endogenous retrovirus and 3) ethical issues related to the future recipients and to society at large. This article will first discuss ongoing work with regards to overcoming the current obstacles. Then, the many potential advantages of using pig organs will be listed. Next, the criteria for selecting the first patients for transplantation with pig organs, will be briefly discussed. Finally, some promising observations made in the context of early attempts at transplanting porcine cells to patients, will be mentioned.
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Nakaya Y, Hoshino S, Yasuda J, Miyazawa T. Mapping of a neutralizing epitope in the surface envelope protein of porcine endogenous retrovirus subgroup B. J Gen Virol 2011; 92:940-4. [PMID: 21228129 DOI: 10.1099/vir.0.029322-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Pigs are thought to be the most suitable donor animal for xenotransplantation. However, pigs harbour potentially hazardous infectious agents, termed porcine endogenous retroviruses (PERVs), in their genome. In this study, we generated a mAb against PERV-B surface (SU) envelope protein (Env), designated KRT1. KRT1 binding was detected by an indirect immunofluorescence assay and flow cytometric analysis on cells infected with PERV-B. KRT1 neutralized PERV-B pseudotype virus and specifically recognized PERV-B SU Env, but not PERV-A SU Env by immunoblotting analysis. The peptide-ELISA revealed that KRT1 recognized a linear peptide sequence (ALEPPHNLPVP) residing in a proline-rich region that is one of the subdomains of SU Env. In conclusion, the KRT1 antibody will serve as a useful tool for the study of PERV-B and, more importantly, it may provide new protective strategies against PERV-B infection in xenotransplantation.
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Affiliation(s)
- Yuki Nakaya
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
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Park SJ, Huh JW, Kim DS, Ha HS, Jung YD, Ahn K, Oh KB, Park EW, Chang KT, Kim HS. Analysis of the molecular and regulatory properties of active porcine endogenous retrovirus gamma-1 long terminal repeats in kidney tissues of the NIH-Miniature pig. Mol Cells 2010; 30:319-25. [PMID: 20811814 DOI: 10.1007/s10059-010-0121-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 06/10/2010] [Accepted: 06/28/2010] [Indexed: 11/26/2022] Open
Abstract
The pig genome contains the gamma 1 family of porcine endogenous retroviruses (PERVs), which are a major obstacle to the development of successful xenotransplantation from pig to human. Long terminal repeats (LTRs) found in PERVs are known to be essential elements for the control of the transcriptional activity of single virus by different transcription factors (TFs). To identify transcribed PERV LTR elements, RT-PCR and DNA sequencing analyses were performed. Twenty-nine actively transcribed LTR elements were identified in the kidney tissues of the NIH-Miniature pig. These elements were divided into two major groups (I and II), and four minor groups (I-1, I-2, I-3, and II-1), by the presence of insertion and deletion (INDEL) sequences. Group I elements showed strong transcriptional activity compared to group II elements. Four different LTR elements (PL1, PL2, PL3, and PL4) as representative of the groups were analyzed by using a transient transfection assay. The regulation of their promoter activity was investigated by treatment with M.SssI (CpG DNA methyltransferase) and garcinol (histone acetyltransferase inhibitor). The transcriptional activity of PERV LTR elements was significantly reduced by treatment with M.SssI. These data indicate that transcribed PERV LTR elements harbor sufficient promoter activity to regulate the transcription of a single virus, and the transcriptional activity of PERV LTRs may be controlled by DNA methylation events.
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Affiliation(s)
- Sang-Je Park
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 609-735, Korea
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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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Yamamoto A, Kobayashi C, Yamashita S, Miyazawa T, Okabe M, Fukuzawa M, Miyagawa S. Expression of complement regulatory protein on porcine endogenous retrovirus (PERV) depends on molecular size. Transpl Immunol 2010; 23:71-6. [DOI: 10.1016/j.trim.2010.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2009] [Accepted: 03/01/2010] [Indexed: 10/19/2022]
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Valdes-Gonzalez R, Dorantes LM, Bracho-Blanchet E, Rodríguez-Ventura A, White DJG. No evidence of porcine endogenous retrovirus in patients with type 1 diabetes after long-term porcine islet xenotransplantation. J Med Virol 2010; 82:331-4. [PMID: 20029803 DOI: 10.1002/jmv.21655] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Xenotransplantation is a promising alternative for donor shortage to ameliorate physiologic and metabolic disorders. The major concern for xenotransplant is the risk of zoonosis mainly by the porcine endogenous retrovirus (PERV), presentation in the piglet genome. Twenty-three patients with type 1 diabetes were transplanted with porcine islets using collagen-generating devices which were implanted subcutaneously in the anterior wall of the abdomen. Clinical characteristics and metabolic tests were recorded in each visit. They were tested for PERV using PCR and RT-PCR from blood pretransplantation and every 3 months during a 4.6- to 8-year follow-up after their first xenotransplant. Tests by PCR of every DNA sample (780 samples) revealed that there was no PERV infection in the DNA of white cells. No evidence of PERV activation was found in this group of patients with type 1 diabetes during clinical long-term follow-up.
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Frühauf JH, Mertsching H, Giri S, Frühauf NR, Bader A. Porcine endogenous retrovirus released by a bioartificial liver infects primary human cells. Liver Int 2009; 29:1553-61. [PMID: 19686312 DOI: 10.1111/j.1478-3231.2009.02087.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND Porcine endogenous retrovirus (PERV) remains a safety risk in pig-to-human xenotransplantation. There is no evidence of in vivo productive infection in humans because PERV is inactivated by human serum. However, PERV can infect human cell lines and human primary cells in vitro and inhibit human immune functions. AIMS We investigated the potential of primary porcine liver cells to transmit PERV to primary human cells in a bioreactor-based bioartificial liver (BAL). METHODS Primary human hepatocytes, endothelial cells and the human cell line HEK 293 were exposed to supernatants from BAL or from the porcine cell line PK-15. PERV polymerase-specific reverse-transcriptase polymerase chain reaction (RT-PCR) and PCR were used to investigate PERV transmission to human cells. An assay of RT activity was used to detect the presence of retrovirus in the supernatants of BAL, primary human hepatocytes and endothelial cells. RESULTS Primary human hepatocytes (hHep), endothelial cells and HEK 293 cells were reproducibly infected by PERV, originating from primary porcine liver cells within the BAL and from PK-15 cells. Infected cells were positive for PERV-specific DNA and RNA after 8-10 days on an average, and RT activity was detectable in the supernatants of infected hHep and HEK 293 cells. CONCLUSION A risk of PERV infection in human cells is documented in this study, indicating that short-term contact of primary porcine liver cell supernatants with primary human cells could result in PERV transmission.
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Affiliation(s)
- Jan-Henning Frühauf
- Department of Cell Techniques and Applied Stem Cell Biology, Biomedical-Biotechnological Center (BBZ), Leipzig, Germany
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de Bruin WB, Güvenç U, Fischhoff B, Armstrong CM, Caruso D. Communicating about xenotransplantation: models and scenarios. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2009; 29:1105-1115. [PMID: 19508450 DOI: 10.1111/j.1539-6924.2009.01241.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Xenotransplantation entails using organs from genetically modified animals as a way to solve the shortage of human organs for transplantation. As with other novel technologies, if xenotransplantation is to be judged fairly, proponents must explain its complex, uncertain, and unfamiliar risks and benefits. Xenotransplantation's risks include the possibility of a recombinant virus infecting human transplant recipients, potentially causing an epidemic of an unfamiliar disease. Using materials vetted by scientific experts, we communicated the variables and relationships determining this risk in three formally equivalent formats: (a) a graphic model, (b) scenarios structured by the graphic model, and (c) both the model and the scenarios. Participants were randomly assigned to receiving one set of materials. They rated them as equally clear and studied them equally long, suggesting similar ease of cognitive processing. Compared to participants receiving the scenarios, those who received the graphic model better identified causes and effects of the risk, and saw less risk of xenotransplantation. Participants who received both the model and the scenarios generally showed intermediate responses. The study demonstrates a general procedure for developing and evaluating formally equivalent graphic and scenario communications regarding highly uncertain risks. In this application to xenotransplantation, presenting a graphic representation improved people's understanding of the risk.
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Affiliation(s)
- Wändi Bruine de Bruin
- Department of Social and Decision Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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Okura E, Ishimaru A, Yamamoto A, Nakatsu S, Shirakura R, Okabe M, Sawa Y, Fukuzawa M, Okumura M, Miyagawa S. Differential human serum-mediated neutralization of PERV released from pig cells transfected with variants of hDAF. Xenotransplantation 2009; 15:365-73. [PMID: 19152664 DOI: 10.1111/j.1399-3089.2008.00496.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Expression of complement regulatory proteins (CRP) on pig endothelial cells (PEC) is an effective means of avoiding induction of hyperacute rejection by human sera. However, pig endogenous retrovirus (PERV) from PEC transfected with CRP may acquire resistance to human sera. This study investigated a form of transfected CRP that is easily expressed on PERV particles. METHODS The PEC line was transfected with the Lac Z gene and PERV-B to investigate PERV infectivity using a Lac Z pseudo-type assay. The cDNAs of several modified DAF (CD55) were then transfected into the PEC(Lac Z)/P-B lines using lipofection. DAF expression was verified by FACS analysis. Complement-dependent PEC lysis was tested to verify the complement regulatory function of the expressed DAF. HEK293 cells were incubated with PEC culture supernatants with or without human sera. The inoculated 293 cells were histochemically stained and Lac Z-positive blue foci were counted. The rate of reduction in Lac Z-positive cells resulting from the addition of human serum was then calculated. In addition, to assess the localization of the expressed DAF, flotation sucrose density analysis was performed. RESULTS While PERV released from PEC expressing delta-short consensus repeat 2 (delta-SCR2) DAF (lacking CRP function) showed no change in resistance to human serum compared to control cells, PERV from cells expressing delta-SCR1 DAF (with CRP function) showed a significant increase in resistance. The DAF-blocking antibody assay indicated that PERV from the DAF transfectants expressed DAF molecules on the surface of the retrovirus. While delta-SCR1 DAF (PI-anchor form) significantly inhibited the reduction of Lac Z-positive cells by human serum, the reduction of Lac Z-positive cells by human serum was less inhibited in the case of transmembrane (TM)-types of DAF-HLA-G, modified influenza hemagglutinin (HA) and MCP (delta-CYT form). However, the reduction in each TM-type DAF was slightly less than that observed in naive and mock cells. The flotation sucrose density analysis of these transfectants indicated that the PI-anchor form of DAF is a raft-associated protein, and most TM-types of DAF are non-raft proteins. CONCLUSION Induction of resistance to human serum in PERV, depends on the form of the CRP tail. The CRP/TM hybrid that does not associate with lipid rafts, is a suitable form of CRP for gene transduction.
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Affiliation(s)
- Eiji Okura
- Division of Organ Transplantation, Department of Molecular Therapeutics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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Ramsoondar J, Vaught T, Ball S, Mendicino M, Monahan J, Jobst P, Vance A, Duncan J, Wells K, Ayares D. Production of transgenic pigs that express porcine endogenous retrovirus small interfering RNAs. Xenotransplantation 2009; 16:164-80. [DOI: 10.1111/j.1399-3089.2009.00525.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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The Baboon in Xenotransplant Research. THE BABOON IN BIOMEDICAL RESEARCH 2009. [PMCID: PMC7120791 DOI: 10.1007/978-0-387-75991-3_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
If cross-species transplantation is ever to become a reasonable therapeutic modality for human beings, it will be because the potential for success has been demonstrated in a nonhuman primate model. The imperative has always been to select a primate research subject from a species that is plentiful, is not endangered, readily procreates in a managed environment, and mimics the human response (immunologic homology) to both organ transplantation and potential transfer of infectious disease. Several Papio subspecies of baboons, including Papio hamadryas anubis (olive baboon), meet these important criteria. These animals remain ubiquitous throughout sub-Saharan Africa and have adapted well to the managed environments of major primate centers worldwide. A list of United States-based primate centers housing breeding colonies of baboons can be found in Table 19.1. The Surgical Research Laboratory at Loma Linda University, for instance, has maintained a salutary relationship with the Southwest National Primate Research Center in San Antonio, Texas, for the procurement of juvenile baboon research subjects.
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Abstract
To overcome the shortage of human organs for transplantation, pigs are considered as xenogeneic donors. However, primarily immunological and virological barriers exist. One of the main virological obstacles, represented by the presence of functional and infectious porcine endogenous retroviruses (PERV) in the genome of the pigs, may be excluded by conventional breeding. In contrast, there are truncated proviral sequences that have the capacity to retrotranspose, causing insertional mutagenesis in the xenograft and in infected human cells. To estimate this risk we have investigated the potential of PERV to retrotranspose. Moloney Murine Leukemia Virus (MoMLV), a gamma type retrovirus and close relative to PERV, which has been described as able to retrotranspose, was implemented as a control. First results based on a neomycin indicator monitoring system indicate that PERV is able to retrotranspose at higher frequencies compared with MoMLV.
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Louz D, Bergmans HE, Loos BP, Hoeben RC. Reappraisal of biosafety risks posed by PERVs in xenotransplantation. Rev Med Virol 2008; 18:53-65. [PMID: 17987669 DOI: 10.1002/rmv.559] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Donor materials of porcine origin could potentially provide an alternative source of cells, tissues or whole organs for transplantation to humans, but is hampered by the health risk posed by infection with porcine viruses. Although pigs can be bred in such a way that all known exogenous microorganisms are eliminated, this is not feasible for all endogenous pathogens, such as the porcine endogenous retroviruses (PERVs) which are present in the germline of pigs as proviruses. Upon transplantation, PERV proviruses would be transferred to the human recipient along with the xenograft. If xenotransplantation stimulates or facilitates replication of PERVs in the new hosts, a risk exists for adaptation of the virus to humans and subsequent spread of these viruses. In a worst-case scenario, this might result in the emergence of a new viral disease. Although the concerns for disease potential of PERVs are easing, only limited pre-clinical and clinical data are available. Small-scale, well-designed and carefully controlled clinical trials would provide more evidence on the safety of this approach and allow a better appreciation of the risks involved. It is therefore important to have a framework of protective measures and monitoring protocols in place to facilitate such initially small scale clinical trials. This framework will raise ethical and social considerations regarding acceptability.
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Affiliation(s)
- Derrick Louz
- GMO office, Substances Expertise Centre of the National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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Butler JE, Sinkora M. The isolator piglet: a model for studying the development of adaptive immunity. Immunol Res 2008; 39:33-51. [PMID: 17917054 DOI: 10.1007/s12026-007-0062-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/28/2022]
Abstract
The period from late gestation to weaning in neonatal mammals is a critical window when the adaptive immune system develops and replaces the protection temporarily provided by passive immunity and pre-adaptive antibodies. It is also when oral tolerance to dietary antigen and the distinction between commensal and pathogenic gut bacteria becomes established resulting in immune homeostasis. The reproductive biology of swine provides a unique model for distinguishing the effects of different factors on immune development during this critical period because all extrinsic factors are controlled by the experimenter. This chapter reviews this early stage of development and the usefulness of the piglet model for understanding events during this transitional stage. The review also describes the major features of the porcine immune system and the immune stimulatory and dysregulatory factors that act during this period. The value of the model to medical science in such areas as food allergy, organ transplantation, cystic fibrosis and the production of humanized antibodies for immuno-therapy is discussed.
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Affiliation(s)
- J E Butler
- Department of Microbiology and Interdisciplinary Graduate Immunology Program, University of Iowa, 3-550 BSB, 51 Newton Rd, Iowa City, IA 52242, USA.
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Cardona K, Milas Z, Strobert E, Cano J, Jiang W, Safley SA, Gangappa S, Hering BJ, Weber CJ, Pearson TC, Larsen CP. Engraftment of adult porcine islet xenografts in diabetic nonhuman primates through targeting of costimulation pathways. Am J Transplant 2007; 7:2260-8. [PMID: 17845561 DOI: 10.1111/j.1600-6143.2007.01933.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Recent advances in human allogeneic islet transplantation have established beta-cell replacement therapy as a potentially viable treatment option for individuals afflicted with Type 1 diabetes. Two recent successes, one involving neonatal porcine islet xenografts transplanted into diabetic rhesus macaques treated with a costimulation blockade-based regimen and the other involving diabetic cynomolgus monkeys transplanted with adult porcine islet xenografts treated with an alternative multidrug immunosuppressive regimen have demonstrated the feasibility of porcine islet xenotransplantation in nonhuman primate models. In the current study, we assessed whether transplantation of adult porcine islet xenografts into pancreatectomized macaques, under the cover of a costimulation blockade-based immunosuppressive regimen (CD28 and CD154 blockade), could correct hyperglycemia. Our findings suggest that the adult porcine islets transplanted into rhesus macaques receiving a costimulation blockade-based regimen are not uniformly subject to hyperacute rejection, can engraft (2/5 recipients), and have the potential to provide sustained normoglycemia. These results provide further evidence to suggest that porcine islet xenotransplantation may be an attainable strategy to alleviate the islet supply crisis that is one of the principal obstacles to large-scale application of islet replacement therapy in the treatment of Type 1 diabetes.
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Affiliation(s)
- K Cardona
- Emory Transplant Center, Department of Surgery, Emory University School of Medicine, Atlanta, GA, USA
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Denner J. Transspecies transmissions of retroviruses: new cases. Virology 2007; 369:229-33. [PMID: 17870141 DOI: 10.1016/j.virol.2007.07.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Revised: 06/13/2007] [Accepted: 07/25/2007] [Indexed: 11/23/2022]
Abstract
Transspecies transmission is common among retroviruses, although the consequences of the transmission are very different. Some transspecies transmissions have resulted in fatal diseases in the new host while others have remained asymptomatic. Some retroviruses are apathogenic in the original species, but pathogenic in a new host and others can be pathogenic or apathogenic in both species. In some cases, endogenization of the retrovirus in the new host has been observed but in others not, while some transmitted retroviruses exist in both forms. Although in most cases transspecies transmission has been observed in one direction only, bidirectional transmissions of caprine and ovine lentiviruses have recently been described. Studies on newly reported natural and experimental transspecies transmissions of the koala retrovirus (KoRV) may help to understand such events.
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Abstract
While the science of animal biotechnology is advancing at a rapid pace, the ethical discussion about the boundaries the public might want to set is at the most nascent stage. There is a tendency in the public debate for opponents to favor an all-out ban on the science, while proponents want to grant it carte blanche. I argue that a more nuanced position on animal biotechnology considers individual projects to be located on a moral continuum, where some are clearly morally justified, others morally impermissible, and some lie in the ethical gray-zone. To begin to define this continuum, we use the bioethical method of casuistry to analyze one case at the end of moral permissibility, and we contrast it with a case that is located at the opposite end of the moral spectrum. I advocate this approach to assessing the moral merit of biotechnology projects because of its attention to the details of individual cases--the protocols, ends, and methods--on which an accurate moral judgment necessarily rests.
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Affiliation(s)
- Autumn Fiester
- Department of Medical Ethics and the Center for Bioethics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-3308, USA.
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Abstract
There are 3 major obstacles to performing transplantations from pig to human. They are as follows: a powerful immune barrier, a potential risk for transmitting microorganisms, particularly endogenous retrovirus from animal-to-human, and ethical issues related to patients and society at large. However, steady progress is currently being made in overcoming these obstacles. Once pig organs can be transplanted into humans, there will be unlimited access to undamaged organs and cells for transplantation, and surgeons will be able to offer transplantations to all needy patients without undue delay. Donation from deceased or live human beings will become obsolete. Furthermore, it will be possible to alleviate graft rejection by genetic modification of the source animal.
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Affiliation(s)
- C G Groth
- Karolinska Institute, Stockholm, Sweden
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37
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Zhang B, Ge B, Xia X, Liu J, Sun L, Rao E, Zhao Y. Compatibility of porcine and human interleukin 2: implications for xenotransplantation. Xenotransplantation 2007; 13:423-32. [PMID: 16925666 DOI: 10.1111/j.1399-3089.2006.00329.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Xenotransplantation provides a possible solution to the severe shortage of allogeneic organ donors. The pig, which shares many physiological similarities with humans, makes it an optimal species for preclinical experimentation and clinical applications. Interleukin 2 (IL2) is a potent growth factor secreted primarily by T helper lymphocytes and it is vital to the cellular expansion required for a productive immune response and the development and peripheral expansion of CD4+CD25+ regulatory T cells. Therefore, it is essential to understand of the compatibility of IL2 between pigs and humans. METHODS We first compared the cDNA and protein sequences and the crystal structures of human and porcine IL2 and IL2 receptors, respectively. The effect of IL2 to induce T cell proliferation was determined by 3H-thymidine incorporation and cell cycle detection. RESULTS Porcine IL2 induced very limited proliferation of human lymphocytes while it functioned well on porcine lymphocytes. Human IL2 had remarkably reduced effects on porcine lymphocytes whereas it worked well on human lymphocytes. CONCLUSION Our present study showed that the interaction of IL2 and IL2R across species might have defects. Together with the wide physiological functions of IL2, our data indicated that physiological disorders could be caused by the poor function of xenogeneic donor IL2 on host cells in full hematopoietic chimera. Our data suggested an additional potential advantage for the mixed xenogeneic chimeras.
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Affiliation(s)
- Baojun Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Transplantation Biology Research Division, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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38
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Abstract
Four clinical trials of porcine islet transplantation have been reported, and there are verbal reports that clinical trials on much larger scales are continuing in centers in China and Russia. The four reported trials are briefly reviewed and, in the light of the present status of experimental islet xenotransplantation, consideration is given to whether such trials are currently justified. The Ethics Committee of the International Xenotransplantation Association has (1) emphasized the need for encouraging studies in non-human primates before clinical trials should be undertaken, (2) mandatory monitoring for the transfer of porcine microorganisms, and (3) careful regulation and oversight by recognized bodies. Other aspects of the topic, such as the need for informed consent, are briefly discussed. We conclude that, at the present time, more data documenting convincing efficacy, focused on clinically applicable immunosuppressive regimens, are needed to justify the initiation of closely monitored clinical trials. A clinical trial may then be justified even though the potential risk to the patients, and possibly for society, will not be zero.
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Affiliation(s)
- P P M Rood
- Division of Immunogenetics, Rangos Research Center, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
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39
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Martina Y, Marcucci KT, Cherqui S, Szabo A, Drysdale T, Srinivisan U, Wilson CA, Patience C, Salomon DR. Mice transgenic for a human porcine endogenous retrovirus receptor are susceptible to productive viral infection. J Virol 2006; 80:3135-46. [PMID: 16537582 PMCID: PMC1440412 DOI: 10.1128/jvi.80.7.3135-3146.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Porcine endogenous retrovirus (PERV) is considered one of the major risks in xenotransplantation. No valid animal model has been established to evaluate the risks associated with PERV transmission to human patients by pig tissue xenotransplantation or to study the potential pathogenesis associated with PERV infection. In previous work we isolated two genes encoding functional human PERV receptors and proved that introduction of these into mouse fibroblasts allowed the normally nonpermissive mouse cells to become productively infected (T. A. Ericsson, Y. Takeuchi, C. Templin, G. Quinn, S. F. Farhadian, J. C. Wood, B. A. Oldmixon, K. M. Suling, J. K. Ishii, Y. Kitagawa, T. Miyazawa, D. R. Salomon, R. A. Weiss, and C. Patience, Proc. Natl. Acad. Sci. USA 100:6759-6764, 2003). In the present study we created mice transgenic for human PERV-A receptor 2 (HuPAR-2). After inoculation of transgenic animals with infectious PERV supernatants, viral DNA and RNA were detected at multiple time points, indicating productive replication. This establishes the role of HuPAR-2 in PERV infection in vivo; in addition, these transgenic mice represent a new model for determining the risk of PERV transmission and potential pathogenesis. These mice also create a unique opportunity to study the immune response to PERV infection and test potential therapeutic or preventative modalities.
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MESH Headings
- Animals
- Animals, Newborn
- Blotting, Western
- Cell Line
- DNA, Viral/analysis
- DNA, Viral/genetics
- DNA, Viral/isolation & purification
- Endogenous Retroviruses/genetics
- Endogenous Retroviruses/isolation & purification
- Endogenous Retroviruses/physiology
- Humans
- Mice
- Mice, Transgenic
- Microscopy, Confocal
- NIH 3T3 Cells
- RNA, Viral/analysis
- RNA, Viral/genetics
- RNA, Viral/isolation & purification
- Receptors, Virus/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/isolation & purification
- Recombinant Proteins/metabolism
- Retroviridae Infections/transmission
- Retroviridae Infections/virology
- Reverse Transcriptase Polymerase Chain Reaction
- Swine/virology
- Time Factors
- Transgenes
- Virus Replication
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Affiliation(s)
- Y Martina
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
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40
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Diekmann S, Bader A, Schmitmeier S. Present and Future Developments in Hepatic Tissue Engineering for Liver Support Systems : State of the art and future developments of hepatic cell culture techniques for the use in liver support systems. Cytotechnology 2006; 50:163-79. [PMID: 19003077 PMCID: PMC3476010 DOI: 10.1007/s10616-006-6336-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Accepted: 01/03/2006] [Indexed: 12/23/2022] Open
Abstract
The liver is the most important organ for the biotransformation of xenobiotics, and the failure to treat acute or acute-on-chronic liver failure causes high mortality rates in affected patients. Due to the lack of donor livers and the limited possibility of the clinical management there has been growing interest in the development of extracorporeal liver support systems as a bridge to liver transplantation or to support recovery during hepatic failure. Earlier attempts to provide liver support comprised non-biological therapies based on the use of conventional detoxification procedures, such as filtration and dialysis. These techniques, however, failed to meet the expected efficacy in terms of the overall survival rate due to the inadequate support of several essential liver-specific functions. For this reason, several bioartificial liver support systems using isolated viable hepatocytes have been constructed to improve the outcome of treatment for patients with fulminant liver failure by delivering essential hepatic functions. However, controlled trials (phase I/II) with these systems have shown no significant survival benefits despite the systems' contribution to improvements in clinical and biochemical parameters. For the development of improved liver support systems, critical issues, such as the cell source and culture conditions for the long-term maintenance of liver-specific functions in vitro, are reviewed in this article. We also discuss aspects concerning the performance, biotolerance and logistics of the selected bioartificial liver support systems that have been or are currently being preclinically and clinically evaluated.
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Affiliation(s)
- Sonja Diekmann
- Center for Biotechnology and Biomedicine, Cell Techniques and Applied Stem Cell Biotechnology, University of Leipzig, Deutscher Platz 5, 04103 Leipzig, Germany
| | - Augustinus Bader
- Center for Biotechnology and Biomedicine, Cell Techniques and Applied Stem Cell Biotechnology, University of Leipzig, Deutscher Platz 5, 04103 Leipzig, Germany
| | - Stephanie Schmitmeier
- Center for Biotechnology and Biomedicine, Cell Techniques and Applied Stem Cell Biotechnology, University of Leipzig, Deutscher Platz 5, 04103 Leipzig, Germany
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41
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Li Z, Ping Y, Shengfu L, Yangzhi Z, Jingqiu C, Youping L, Hong B. Variation of host cell tropism of porcine endogenous retroviruses expressed in chinese Banna minipig inbred. Intervirology 2006; 49:185-91. [PMID: 16407655 DOI: 10.1159/000090787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 06/13/2005] [Indexed: 02/05/2023] Open
Abstract
A serious donor-organ shortage urges the use of animal donors to treat a wide appropriate variety of major health problems including organ failure and diabetes. However, the promise of clinical xenotransplantation is offset at the present time by the potential of a public health risk due to the cross-species transmission of pathogens from animal donors to human patients. In particular, the transmission of porcine endogenous retrovirus (PERV) is a major concern. In this study, cell tropism of PERV was tested by in vitro infection of human primary cells and cell lines. Coculture of PERV supernatant derived from PK15 with human primary cells and cell lines resulted in the transfer and expression of PERV-specific sequences and the establishment of a productive infection. In the detection of tropism variation of PERV in pigs, 293 cells were cocultured with mitogenic-activated and lethally irradiated PBMC from 12 Banna minipig inbred (BMI). The results were that six coculture groups were PERV-positive. However, infectious virus was not detected when activated PBMC from the other 7 pigs were cocultivated with human cells known to be permissive for PERV, which indicated a tropism variation among the tested individuals. All these findings demonstrate that the presence of endogenous viruses in source animals needs to be carefully considered when the infectious disease potential of xenotransplantation is being assessed.
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Affiliation(s)
- Zhang Li
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University, Chengdu, PR China
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42
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Schmidt P, Forsman A, Andersson G, Blomberg J, Korsgren O. Pig islet xenotransplantation: activation of porcine endogenous retrovirus in the immediate post-transplantation period. Xenotransplantation 2005; 12:450-6. [PMID: 16202068 DOI: 10.1111/j.1399-3089.2005.00244.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Porcine endogenous retroviruses (PERV) are considered as the main infectious barrier in islet xenotransplantation. PERV has been shown to infect, but not to cause symptomatic disease in mice after islet transplantation. In vivo activation of PERV have so far not been examined. Expression of PERV was examined in adult and fetal porcine islets with or without the presence of known retroviral inducers or after transplantation to rats. METHODS Isolated adult and fetal porcine islets were cultured under normal conditions or in the presence of dexamethasone or 5-azacytidine and 5-iodo-2-deoxyuridine. PERV mRNA content was analyzed by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and culture supernatants were analyzed for the presence of retroviral RT. Also, fetal islets were transplanted under the kidney capsule of immunocompetent or nude athymic rats. Expression of PERV mRNA in the grafts was evaluated by real-time quantitative RT-PCR. Infiltration of immunocompetent cells were evaluated by immunohistochemistry. RESULTS Both fetal and adult islets in culture produced small or even undetectable amounts of PERV mRNA and retroviral RT. PERV expression was not enhanced by retroviral inducers. In contrast, activation of PERV expression was observed the first day after transplantation of fetal islet-like cell clusters in both athymic and normal rats. PERV expression peaked after 1 to 3 days and was then rapidly returned to background levels. PERV expression neither correlated with the innate immune response seen in athymic rats nor with the specific process of rejection in normal rats. CONCLUSION Both fetal and adult islets produce low amounts of PERV mRNA in culture. After transplantation PERV expression is induced, seemingly independent of both the unspecific inflammatory response and the specific T-cell-mediated rejection process. It is speculated that PERV expression is correlated with the level of hypoxia in the islet xenograft.
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Affiliation(s)
- Peter Schmidt
- The Rudbeck Laboratory, Division of Clinical Immunology, Uppsala University, Uppsala, Sweden.
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43
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Bailey LL. Candid observations on the current status of xenotransplantation. Xenotransplantation 2005; 12:428-31; discussion 431-3. [PMID: 16202064 DOI: 10.1111/j.1399-3089.2005.00240_1.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Amit M, Winkler ME, Menke S, Brüning E, Büscher K, Denner J, Haverich A, Itskovitz-Eldor J, Martin U. No evidence for infection of human embryonic stem cells by feeder cell-derived murine leukemia viruses. Stem Cells 2005; 23:761-71. [PMID: 15917472 DOI: 10.1634/stemcells.2004-0046] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Until recently, culture and expansion of nondifferentiated human embryonic stem cells (hESCs) depended on coculture with murine embryonic fibroblasts. Because mice are known to harbor a variety of pathogens, such culture conditions implicate the risk of xenozoonoses. Among these pathogens, endogenous retroviruses, including murine leukemia viruses (MuLVs), are of special importance. It is well known that some strains cause pathogenic (e.g., leukemic) effects and that xenotropic, polytropic, and amphotropic MuLVs are able to infect human cells. In view of potential clinical applications of hESC lines, it is therefore imperative to investigate potential infection of hESCs by mouse feeder cell-derived viruses. As a first step towards a comprehensive infection risk assessment, we have analyzed embryonic fibroblasts derived from different mouse strains for expression and release of xenotropic, polytropic, and amphotropic MuLVs. Moreover, several hESC lines have been investigated for expression of specific receptors for xenotropic/polytropic MuLVs, as well as for MuLV infection and expression. Evidence for expression of humantropic MuLVs was found in cultures of mouse embryonic fibroblasts (MEFs). Moreover, expression of specific receptors for xenotropic/ polytropic MuLV on human HEK293 and hESC lines and infection after coculture with an MuLV-producing mink cell line could be demonstrated. In contrast, no evidence of MuLV transmission from MEFs to human HEK293 cells or to the hESC lines I-3, I-6, I-8, and H-9 has been obtained. Our results suggest that recently established hESC lines are free of MuLV infections despite long-term close contact with MEFs.
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Affiliation(s)
- Michal Amit
- Department of Obstetrics and Gynecology, Rambam Medical Center, Faculty of Medicine, The Technion, Haifa, Israel
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45
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Valdés-González RA, Dorantes LM, Garibay GN, Bracho-Blanchet E, Mendez AJ, Dávila-Pérez R, Elliott RB, Terán L, White DJG. Xenotransplantation of porcine neonatal islets of Langerhans and Sertoli cells: a 4-year study. Eur J Endocrinol 2005; 153:419-27. [PMID: 16131605 DOI: 10.1530/eje.1.01982] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Porcine islets of Langerhans for xenotransplantation into humans have been proposed as a solution to the shortage of human donors. Rejection is one of the main constraints. This study presents the results of a clinical trial using a novel method for transplanting and immunoprotecting porcine islets in type 1 diabetic patients. DESIGN A 4-year follow up of a clinical trial involving 12 patients, with no immunosuppressive drugs at any point. Eleven age matched untransplanted diabetics served as controls. METHODS We have developed a procedure for protecting neonatal porcine islets by combining them with Sertoli cells and placing them in a novel subcutaneous autologous collagen-covered device. RESULTS In the patients in the treatment group, no complications arose and no porcine endogenous retrovirus infection was detected. Half of the patients showed a significant reduction in insulin requirements compared with both their pre transplant levels and controls, and this reduction was maintained for up to 4 years. Two patients became insulin-independent for several months. Porcine insulin was detected in three patients' sera following glucose stimulation up to 4 years post transplant. Three years post transplant, one of four devices was removed from four patients, and the presence of insulin-positive cells in the transplant was demonstrated by immunohistology in all 4 patients. CONCLUSIONS Long-term cell survival with concurrent positive effects on metabolic control are possible by this technique.
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46
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Vasavada RC, Gonzalez-Pertusa JA, Fujinaka Y, Fiaschi-Taesch N, Cozar-Castellano I, Garcia-Ocaña A. Growth factors and beta cell replication. Int J Biochem Cell Biol 2005; 38:931-50. [PMID: 16168703 DOI: 10.1016/j.biocel.2005.08.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 07/20/2005] [Accepted: 08/10/2005] [Indexed: 01/08/2023]
Abstract
Recent studies have demonstrated that human islet allograft transplantation can be a successful therapeutic option in the treatment of patients with Type I diabetes. However, this impressive recent advance is accompanied by a very important constraint. There is a critical paucity of pancreatic islets or pancreatic beta cells for islet transplantation to become a large-scale therapeutic option in patients with diabetes. This has prompted many laboratories around the world to invigorate their efforts in finding ways for increasing the availability of beta cells or beta cell surrogates that potentially could be transplanted into patients with diabetes. The number of studies analyzing the mechanisms that govern beta cell proliferation and growth in physiological and pathological conditions has increased exponentially during the last decade. These studies exploring the role of growth factors, intracellular signaling molecules and cell cycle regulators constitute the substrate for future strategies aimed at expanding human beta cells in vitro and/or in vivo after transplantation. In this review, we describe the current knowledge on the effects of several beta cell growth factors that have been shown to increase beta cell proliferation and expand beta cell mass in vitro and/or in vivo and that they could be potentially deployed in an effort to increase the number of patients transplanted with islets. Furthermore, we also analyze in this review recent studies deciphering the relevance of these specific islet growth factors as physiological and pathophysiological regulators of beta cell proliferation and islet growth.
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Affiliation(s)
- Rupangi C Vasavada
- Division of Endocrinology, University of Pittsburgh, BST-E1140, PA 15261, USA
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47
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Liu Q, Liu Z, Dalakas E. Prevalence of porcine endogenous retrovirus in Chinese pig breeds and in patients treated with a porcine liver cell-based bioreactor. World J Gastroenterol 2005; 11:4727-30. [PMID: 16094718 PMCID: PMC4615419 DOI: 10.3748/wjg.v11.i30.4727] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine the prevalence of porcine endogenous retrovirus (PERV) in various pig breeds raised in China including Chinese experimental mini-pigs by PERV-reverse transcriptase (PERV-RT enzyme). Moreover, the potential for infection of PERV was investigated in patients treated with a bioreactor based on porcine liver cells (n = 3).
METHODS: Pig serum, liver and muscle cell-free supernatants were collected from various Chinese pig breeds. Porcine hepatocytes were isolated with a two-step perfusion method. Three patients with acute or chronic liver failure were treated with a bioartificial liver support system (BALSS) for 8-12 h and serum samples were collected from the patients before, immediately after and 30 d after treatment.
RESULTS: The activities of PERV-RT enzyme in pig liver and muscle cell-free supernatants were higher than in normal human controls. PERV-TR enzyme activity did not increase in patients before and after 1 mo of treatment. PERV-RT activities were not significantly different when compared with pre-treatment group (1.544 ± 0.155576), the post-treatment groups (1.501 ± 0.053507, 1.461 ± 0.033808 and 1.6006667 ± 0.01963 for 0, 14 and 30 d post-treatment, respectively, P > 0.05), and normal control group (1.440 ± 1.0641, P > 0.05). RT enzyme activity in Chinese experimental mini-pigs was higher than in normal human control group (1.440 ± 1.0641 U/mL, P < 0.05), and not significantly different (P > 0.05) when compared with the pig breeds except in the muscle supernatants. All the samples including muscle and liver cell supernatants from the Chinese mini-experimental pigs and the four domestic Chinese pig breeds contained PERVs.
CONCLUSION: These results suggest that the risk of PERV infection through BALSS containing porcine liver cells without immunosuppressants may be quite low. Although there were PERVs in Chinese experimental mini-pigs and porcine liver cell culture suspensions, we did not find any evidence of persistent PERV infection in patients treated with this porcine hepatocyte-based bioartificial liver.
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Affiliation(s)
- Qing Liu
- Artificial Liver Treatment and Training Center, Beijing Youan Hospital, Capital University of Medical Sciences, China.
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48
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Abstract
Currently, the number of patients awaiting transplantation is continuously increasing, and shortage of available deceased organ donors is the major limitation for organ and cell allotransplantation. Research to develop alternative sources of tissues is ongoing and xenogeneic organs or cells represent an attractive solution. This review focuses on recent progress achieved in this field, including the development of newly genetically modified animal donors and new immunosuppressive approaches. As xenotransplantation is moving closer to clinical application, future perspectives must establish guidelines to ensure that future clinical trials are carried out ethically and safely.
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Affiliation(s)
- Pascal Bucher
- Surgical Research Unit, Department of Surgery, University Hospital Geneva, Switzerland
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49
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Zhang L, Yu P, Li S, Li Y, Zeng Y, Cheng J, Bu H. Phylogenetic analysis of porcine endogenous retrovirus variation in three Chinese pigs. Transplant Proc 2005; 36:2495-7. [PMID: 15561294 DOI: 10.1016/j.transproceed.2004.07.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PCR amplification was performed on genomic DNA extracted from peripheral blood lymphocytes of three species of Chinese pigs (Banna minipig inbreed [BMI], Wu-Zhi-Shan pig [WZSP], and Nei jiang pig [NJP]), using primers corresponding to the highly conserved regions of polymerase (pol) gene. Extracted PCR products were then cloned in a pGEM-T vector. Phylogenetic analysis of the nucleotide sequences of BMI-PERV, NJJP-PERV, and WZSP-PERV revealed them to be a novel category of PERV. In comparison to other type C retrovirus and lentivirus, their amino acid sequenced show about 30% to 57.7% identities. Our previous research demonstrated that PERV in the three pigs was highly expressed. It appears likely that functional loci encoding these novel PERV sequences exist, but this remains to be established. The novel sequences described in this report will allow such investigations to be actively pursued.
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Affiliation(s)
- L Zhang
- Laboratory of Transplant Engineering and Immunology, West China Hospital, Sichuan University, Chengdu, People's Republic of China
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50
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Winkler ME, Winkler M, Burian R, Hecker J, Loss M, Przemeck M, Lorenz R, Patience C, Karlas A, Sommer S, Denner J, Martin U. Analysis of pig-to-human porcine endogenous retrovirus transmission in a triple-species kidney xenotransplantation model. Transpl Int 2005; 17:848-58. [PMID: 15864489 DOI: 10.1007/s00147-005-0808-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2003] [Revised: 12/01/2003] [Accepted: 05/04/2004] [Indexed: 10/25/2022]
Abstract
Clinical pig-to-human xenotransplantation might be associated with the risk of transmission of xenozoonoses, especially porcine endogenous retroviruses (PERVs). We have established a pig-to-humanised-cynomolgus monkey xenotransplantation model allowing the analysis of potential PERV-transmission from normal or transgenic porcine organs to human vascular tissue. Pig-to-human kidney xenotransplantation was performed in cynomolgus monkeys. An interposition graft constructed from a human saphena vein replaced the porcine kidney vein. After graft rejection and/or death of the recipient (survival 2, 4, 6, 13, 16, 19 days), the human interposition grafts were removed. Human endothelial cells (huECs) were isolated from the interposition grafts and cultivated in vitro. Explanted human vascular tissue, isolated huECs, plasma and serum samples of the graft recipients were characterised by flow cytometry and immunohistochemistry and screened for indications of PERV transmission by quantitative polymerase chain reaction (PCR), reverse transcriptase-polymerase chain reaction (RT-PCR) and RT assay. PERV-specific immune response of recipients was analysed by Western blot. No evidence of PERV infection or PERV-specific immune response was detected.
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Affiliation(s)
- Monica E Winkler
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover, Germany.
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