Xenotransplantation: Pig's organs are "blessed"
Xenotransplantation: Pig's organs are "blessed" December 14, 2018 Source: Science and Technology Daily “If xenotransplantation can be extended from basic research to clinical research, it will be used in large-scale clinical applications in the future, which may give millions of patients hope to regain their lives. But like all new technologies, it also has its own risks. Such as immune rejection, the risk of infectious diseases, etc. Therefore, all parties need to reach a consensus, do a comprehensive technical and ethical protection, and reduce the risk to zero." On December 12-14, at the 3rd International Symposium on Clinical Research Standards for Global Xenotransplantation held in Changsha, Leo Buhler, President of the International Society of Xenografts, said. Xenotransplantation, in simple terms, transplants an animal's cells, tissues or organs into another animal. Humans hope to solve the problem of transplant donor shortage and cure human diseases through this technology, in line with safety and ethics. Ten years ago, the team of Professor Wang Wei from the Third Xiangya Hospital of Central South University on the "porcine islet transplantation" research took the lead in making a major breakthrough in the world. In November 2008, China’s first international standard for xenotransplantation, the Changsha Declaration, was born. The Declaration sets out the basic principles to be followed in conducting this clinical study by all UN member states and the basic biosafety conditions that must be met. "This is due to immune rejection, the risk of transmission of infectious diseases and ethical considerations." Wang Wei said. For example, primates are prone to cross-species virus infections such as HIV. Cattle are excluded because of the risk of "mad cow disease" that can be shared by humans and animals. There are also ethical constraints on primate xenotransplantation. After comprehensive consideration, the pigs appear to be "blessed". Studies have shown that pig's heart, liver, kidney, islets, nerve cells, cornea and chondrocytes, bone tissue, heart valves, etc., are almost identical in structure and function to human counterparts, tissues and cells, and almost complete exchange. Moreover, there is no "tangledness" of ethical issues, and there is no serious and inevitable "community disease". “After experiencing SARS and global avian influenza outbreaks, there is even greater concern about the spread of cross-species diseases that xenotransplants may bring. Especially endogenous retroviruses, which are in the genome of most mammals, including pigs. All exist. Under normal circumstances, the virus rarely causes damage to animal cells. However, once it crosses the inter-species barrier, it may proliferate and cause disease in the new host, and ultimately endanger public health through interpersonal transmission." Wang Wei said. Therefore, only “specified pathogen pigs†fed under special circumstances can become the main research target of xenotransplantation. The source of such donor pigs is particular. Newborn pigs obtained by experimental animal pigs (SPF pigs) by "caesarean section" must be fed into a limited bacteria isolator and cultivated into adult pigs to form "pigs second generation". The “Pig II†has been tested and does not contain hundreds of bacteria, fungi, parasites and viruses designated by WHO to be “qualifiedâ€. After 20 years of research, Wang Wei team has achieved world-leading results in biosafety and immune rejection: screening and breeding of the designated pathogen-free pig "Heter Seed No. 1" with high islet content and easy breeding; established Asia One, the world's second xenograft donor breeding center; the first internationally established transplant donor culture - pig islet extraction - a complete technical system for clinical application... based on this series of major original technological innovations, they are Internationally, the first to apply heterologous islet transplantation to the clinical treatment of type I diabetes. In May of this year, the "porcine islet transplantation treatment of diabetes technology" passed the medical technology filing of the Hunan Provincial Health Planning Commission to limit clinical application. This is also the first clinical application license for live cell xenografts in pigs worldwide. In the issue of immune rejection, existing xenograft research mainly relies on genetic modification methods and the use of immunosuppressive drugs to reduce rejection. However, the high level of immunosuppressive drugs has also become a "hard injury" in the clinical application of xenotransplantation. The Wang Wei team is embarking on the development of immunoisolation technology and supporting programs. Once successful, it will hope to maximize the survival of porcine islet cells in patients and maximize the efficacy. At present, the corresponding research and development work has entered the pre-clinical large animal research stage. He revealed that the team has now completed a preclinical study of porcine nerve cell transplantation for Parkinson's disease. “The era of pigs contributing to the treatment of human diseases has begun.†“Although this technology has not yet been clinically promoted, the most recent application of “near†is worth considering. For example, it is now possible to transplant a pig heart to a primate for up to six months,†Leo Buhler said. At least one idea is provided that pig xenografts can be used as a 'buffering' solution for acute illnesses such as acute heart failure and liver failure, helping to prolong the patient's waiting time for a suitable human organ supply." In addition to exploring technology, the seminar will further improve the international standards for xenograft clinical research, namely the revision of the Changsha Declaration. "New developments, new changes, and new technologies that have emerged in the past decade have been 'promoting' the introduction of the new "Changsha Declaration," said WHO Representative Jose Ramon Nunez. X Ray Lead Suspender Skirt,0.35 Xray Lead Skirt,0.5 X-Ray Lead Suspender Apron,Radiation Proof Lead Skirt Longkou Kangxie Medical Instrument Co., Ltd , https://www.sdkangxiemedical.com
Technically, xenotransplantation must address two major difficulties, such as immune rejection and the risk of infectious disease safety. According to WHO and the International Society of Xenografts, pigs are the only available xenograft donors to date.