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The New England Journal of Medicine Jul 2022A 57-year-old man with nonischemic cardiomyopathy who was dependent on venoarterial extracorporeal membrane oxygenation (ECMO) and was not a candidate for standard...
A 57-year-old man with nonischemic cardiomyopathy who was dependent on venoarterial extracorporeal membrane oxygenation (ECMO) and was not a candidate for standard therapeutics, including a traditional allograft, received a heart from a genetically modified pig source animal that had 10 individual gene edits. Immunosuppression was based on CD40 blockade. The patient was weaned from ECMO, and the xenograft functioned normally without apparent rejection. Sudden diastolic thickening and failure of the xenograft occurred on day 49 after transplantation, and life support was withdrawn on day 60. On autopsy, the xenograft was found to be edematous, having nearly doubled in weight. Histologic examination revealed scattered myocyte necrosis, interstitial edema, and red-cell extravasation, without evidence of microvascular thrombosis - findings that were not consistent with typical rejection. Studies are under way to identify the mechanisms responsible for these changes. (Funded by the University of Maryland Medical Center and School of Medicine.).
Topics: Animals; Animals, Genetically Modified; Extracorporeal Membrane Oxygenation; Heart; Heart Transplantation; Heterografts; Humans; Immunosuppression Therapy; Swine; Transplantation, Heterologous
PubMed: 35731912
DOI: 10.1056/NEJMoa2201422 -
Nature Reviews. Nephrology Dec 2022A major limitation of organ allotransplantation is the insufficient supply of donor organs. Consequently, thousands of patients die every year while waiting for a... (Review)
Review
A major limitation of organ allotransplantation is the insufficient supply of donor organs. Consequently, thousands of patients die every year while waiting for a transplant. Progress in xenotransplantation that has permitted pig organ graft survivals of years in non-human primates has led to renewed excitement about the potential of this approach to alleviate the organ shortage. In 2022, the first pig-to-human heart transplant was performed on a compassionate use basis, and xenotransplantation experiments using pig kidneys in deceased human recipients provided encouraging data. Many advances in xenotransplantation have resulted from improvements in the ability to genetically modify pigs using CRISPR-Cas9 and other methodologies. Gene editing has the capacity to generate pig organs that more closely resemble those of humans and are hence more physiologically compatible and less prone to rejection. Despite such modifications, immune responses to xenografts remain powerful and multi-faceted, involving innate immune components that do not attack allografts. Thus, the induction of innate and adaptive immune tolerance to prevent rejection while preserving the capacity of the immune system to protect the recipient and the graft from infection is desirable to enable clinical xenotransplantation.
Topics: Humans; Animals; Swine; Transplantation, Heterologous; Graft Survival; Primates; Tissue and Organ Procurement; Transplants; Graft Rejection
PubMed: 36198911
DOI: 10.1038/s41581-022-00624-6 -
Frontiers in Immunology 2019The 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... (Review)
Review
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.
Topics: Animals; Animals, Genetically Modified; Biomarkers; Blood Coagulation Disorders; Disease Management; Gene Expression Regulation; Graft Rejection; Graft Survival; Haplorhini; Humans; Immunity, Cellular; Immunity, Humoral; Models, Animal; Species Specificity; Swine; Translational Research, Biomedical; Transplantation Immunology; Transplantation, Heterologous
PubMed: 32038617
DOI: 10.3389/fimmu.2019.03060 -
Frontiers in Immunology 2022Transplantation is often the last resort for end-stage organ failures, e.g., kidney, liver, heart, lung, and pancreas. The shortage of donor organs is the main limiting... (Review)
Review
Transplantation is often the last resort for end-stage organ failures, e.g., kidney, liver, heart, lung, and pancreas. The shortage of donor organs is the main limiting factor for successful transplantation in humans. Except living donations, other alternatives are needed, e.g., xenotransplantation of pig organs. However, immune rejection remains the major challenge to overcome in xenotransplantation. There are three different xenogeneic types of rejections, based on the responses and mechanisms involved. It includes hyperacute rejection (HAR), delayed xenograft rejection (DXR) and chronic rejection. DXR, sometimes involves acute humoral xenograft rejection (AHR) and cellular xenograft rejection (CXR), which cannot be strictly distinguished from each other in pathological process. In this review, we comprehensively discussed the mechanism of these immunological rejections and summarized the strategies for preventing them, such as generation of gene knock out donors by different genome editing tools and the use of immunosuppressive regimens. We also addressed organ-specific barriers and challenges needed to pave the way for clinical xenotransplantation. Taken together, this information will benefit the current immunological research in the field of xenotransplantation.
Topics: Animals; Graft Rejection; Heterografts; Humans; Organ Transplantation; Swine; Tissue Donors; Transplantation, Heterologous
PubMed: 35967435
DOI: 10.3389/fimmu.2022.928173 -
Frontiers in Immunology 2022Organ allotransplantation has now reached an impassable ceiling inherent to the limited supply of human donor organs. In the United States, there are currently over... (Review)
Review
Organ allotransplantation has now reached an impassable ceiling inherent to the limited supply of human donor organs. In the United States, there are currently over 100,000 individuals on the national transplant waiting list awaiting a kidney, heart, and/or liver transplant. This is in contrast with only a fraction of them receiving a living or deceased donor allograft. Given the morbidity, mortality, costs, or absence of supportive treatments, xenotransplant has the potential to address the critical shortage in organ grafts. Last decade research efforts focused on creation of donor organs from pigs with various genes edited out using CRISPR technologies and utilizing non-human primates for trial. Three groups in the United States have recently moved forward with trials in human subjects and obtained initial successful results with pig-to-human heart and kidney xenotransplantation. This review serves as a brief discussion of the recent progress in xenotransplantation research, particularly as it concerns utilization of porcine heart, renal, and liver xenografts in clinical practice.
Topics: Animals; Heterografts; Humans; Primates; Swine; Tissue Donors; Transplantation, Heterologous; Transplants; United States
PubMed: 35757701
DOI: 10.3389/fimmu.2022.900594 -
British Medical Bulletin Mar 2018There is a continuing worldwide shortage of organs from deceased human donors for transplantation into patients with end-stage organ failure. Genetically engineered pigs... (Review)
Review
INTRODUCTION
There is a continuing worldwide shortage of organs from deceased human donors for transplantation into patients with end-stage organ failure. Genetically engineered pigs could resolve this problem, and could also provide tissues and cells for the treatment of conditions such as diabetes, Parkinson's disease and corneal blindness.
SOURCES OF DATA
The current literature has been reviewed.
AREAS OF AGREEMENT
The pathobiologic barriers are now largely defined. Research progress has advanced through the increasing availability of genetically engineered pigs and novel immunosuppressive agents. Life-supporting pig kidneys and islets have functioned for months or years in nonhuman primates.
AREAS OF CONTROVERSY
The potential risk of transfer of a pig infectious microorganism to the recipient continues to be debated.
GROWING POINTS
Increased attention is being paid to selection of patients for initial clinical trials.
AREAS TIMELY FOR DEVELOPING RESEARCH
Most of the advances required to justify a clinical trial have now been met.
Topics: Animals; Animals, Genetically Modified; Graft Survival; Heterografts; Humans; Swine; Tissue and Organ Harvesting; Transplantation, Heterologous
PubMed: 29228112
DOI: 10.1093/bmb/ldx043 -
Transplant International : Official... Nov 2021The future clinical application of animal-to-human transplantation (xenotransplantation) is of importance to society as a whole. Favourable preclinical data relevant to... (Review)
Review
The future clinical application of animal-to-human transplantation (xenotransplantation) is of importance to society as a whole. Favourable preclinical data relevant to cell, tissue and solid organ xenotransplants have been obtained from many animal models utilizing genetic engineering and protocols of pathogen-free husbandry. Findings have reached a tipping point, and xenotransplantation of solid organs is approaching clinical evaluation, the process of which now requires close deliberation. Such discussions include considering when there is sufficient evidence from preclinical animal studies to start first-in-human xenotransplantation trials. The present article is based on evidence and opinions formulated by members of the European Society for Organ Transplantation who are involved in the Transplantation Learning Journey project. The article includes a brief overview of preclinical concepts and biology of solid organ xenotransplantation, discusses the selection of candidates for first-in-human studies and considers requirements for study design and conduct. In addition, the paper emphasizes the need for a regulatory framework for xenotransplantation of solid organs and the essential requirement for input from public and patient stakeholders.
Topics: Animals; Heterografts; Humans; Models, Animal; Organ Transplantation; Transplantation, Heterologous; Transplants
PubMed: 34459040
DOI: 10.1111/tri.14031 -
American Journal of Transplantation :... Apr 2022A radical solution is needed for the organ supply crisis, and the domestic pig is a promising organ source. In preparation for a clinical trial of xenotransplantation,...
A radical solution is needed for the organ supply crisis, and the domestic pig is a promising organ source. In preparation for a clinical trial of xenotransplantation, we developed an in vivo pre-clinical human model to test safety and feasibility tenets established in animal models. After performance of a novel, prospective compatible crossmatch, we performed bilateral native nephrectomies in a human brain-dead decedent and subsequently transplanted two kidneys from a pig genetically engineered for human xenotransplantation. The decedent was hemodynamically stable through reperfusion, and vascular integrity was maintained despite the exposure of the xenografts to human blood pressure. No hyperacute rejection was observed, and the kidneys remained viable until termination 74 h later. No chimerism or transmission of porcine retroviruses was detected. Longitudinal biopsies revealed thrombotic microangiopathy that did not progress in severity, without evidence of cellular rejection or deposition of antibody or complement proteins. Although the xenografts produced variable amounts of urine, creatinine clearance did not recover. Whether renal recovery was impacted by the milieu of brain death and/or microvascular injury remains unknown. In summary, our study suggests that major barriers to human xenotransplantation have been surmounted and identifies where new knowledge is needed to optimize xenotransplantation outcomes in humans.
Topics: Animals; Animals, Genetically Modified; Graft Rejection; Heterografts; Humans; Kidney; Prospective Studies; Swine; Transplantation, Heterologous
PubMed: 35049121
DOI: 10.1111/ajt.16930 -
American Journal of Transplantation :... Apr 2022
Topics: Heterografts; Transplantation, Heterologous
PubMed: 35073605
DOI: 10.1111/ajt.16963 -
EBioMedicine Jun 2023Peritoneal metastasis is a challenging aspect of clinical practice for gastric cancer. Animal models are crucial in understanding molecular mechanisms, assessing drug... (Review)
Review
Peritoneal metastasis is a challenging aspect of clinical practice for gastric cancer. Animal models are crucial in understanding molecular mechanisms, assessing drug efficacy, and conducting clinical intervention studies, including those related to gastric cancer peritoneal metastasis. Unlike other xenograft models, peritoneal metastasis models should not only present tumor growth at the transplant site, but also recapitulate tumor cell metastasis in the abdominal cavity. Developing a reliable model of gastric cancer peritoneal metastasis involves several technical aspects, such as the selection of model animals, source of xenograft tumors, technology of transplantation, and dynamic monitoring of the tumor progression. To date, challenges remain in developing a reliable model that can completely recapitulate peritoneal metastasis. Thus, this review aims to summarize the techniques and strategies used to establish animal models of gastric cancer peritoneal metastasis, providing a reference for future model establishment.
Topics: Animals; Humans; Peritoneal Neoplasms; Stomach Neoplasms; Peritoneum; Transplantation, Heterologous; Heterografts; Cell Line, Tumor
PubMed: 37182268
DOI: 10.1016/j.ebiom.2023.104601