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  • Essay / Xenotransplantation as a technology

    Xenotransplantation could be used to treat severe burns, addressing the issue of closure and coverage, the best source currently being fresh cadaver allografts, of which there is a large shortage (Ge, et al., 2010). A promising breakthrough was the use of genetically modified pig skin CTLA4Ig (cytotoxic T lymphocyte-associated antigen 4 immunoglobulin) as a wound dressing using Ad5F35 as a viral carrier for delivery (Ge, and al., 2010). However, acute immune rejection means that the survival of this skin is always less than 14 days (not long enough to meet needs); therefore, current methods such as thin-thickness autologous skin grafts (dermis and epidermis skin layers taken from part of a patient and transplanted onto the burn), cultured epidermis sheets, artificial materials and cultured cell matrices are preferable (Ge, et al., 2010).Say no to plagiarism. Get a tailor-made essay on “Why violent video games should not be banned”? Get the original essay Livers have been designed for xenotransplantation which can produce antibodies against the host's immune cells, this "dew drop gelatinous” protects the pancreatic islet cells of the immune system. host system (Reardon, 2015). This product is called Diabecell and is in late-stage clinical trials, with patients surviving 9 years without signs of rejection or infection (Reardon, 2015). Pancreatic islet cells alone hold great promise, as they are much easier to transplant than solid organs (González, 2012). This could treat diabetes without resorting to immunosuppression (María Jorqui Azofra, 2012). Although more life-threatening in the event of failure (15% of heart transplant patients die within a month of surgery (Strachan, 2015)), cardiac xenotransplantations have been shown to be more effective than other organs . A baboon received a genetically modified pig heart and survived for 2.5 years (Reardon, 2015); in this case, the α-gal-free heart transplanted by surgeon Muhammad Mohiuddin did not replace the baboon's heart itself (Reardon, 2015). Kidney transplants seem more promising (Reardon, 2015); with an average wait time of 3 years for kidneys, demand is high (Strachan, 2015). The only alternative is the intrusive and intense treatment of dialysis; it takes time out of your life, limits fluid intake, and increases the risk of heart attack or stroke (Strachan, 2015). Kidney xenotransplantations have been relatively successful, with one transplanted kidney functioning in a baboon for 4 months (Reardon, 2015). When I spoke to Dr. David Cooper, a leading xenotransplantation researcher, he told me, “I believe the first patients to enter a clinical trial will be those awaiting kidney transplants. If the test fails, the pig kidney can be removed and the patient can return to dialysis (if this is even possible). (Cooper, 2018). This shows that a failed kidney xenotransplantation would not always be fatal, making it more suitable for clinical trials. There are a multitude of organs and tissues that could be used for xenotransplantation. Cornea, for example, was already approved for commercialization in China in April 2015 (Reardon, 2015). The lung is another organ in high demand for which xenotransplantation could provide the solution; However, the lungs' extensive network of blood vessels has proven "extremely difficult to transplant", increasing the chances of contactblood between the donor and the host, which increases the risk of rejection (Reardon, 2015). A factory farm has been designed to produce 1,000 pig lungs per year (Mountain, 2015), which could help alleviate the shortage that led to 56 deaths in the UK in 2014 alone (Strachan, 2015). Lungs are often unsuitable for transplantation (23% are not offered), with half of people with cystic fibrosis (a genetic disease that affects the functioning of the lungs) needing a lung transplant as an adult, the shortage means that a third of these people will be. die before this transplant can occur (Strachan, 2015). Lung xenotransplants are the most difficult organ to transplant, requiring the modification of 12 genes to make it suitable; in 2014, United Therapeutics successfully deleted 6 of these genes (McNamee, 2014). The source of these organs would most likely be the domestic pig, Sus scrofa domestica (Magdalena Hryhorowicz, 2017). Pigs would be more suitable for a number of reasons, primarily because they have organs similar in size and function to humans (Griffin, 2017). Although they do not constitute a perfect genetic match, primates, which constitute the alternative (better genetic compatibility), have organs that are too small and are therefore not suitable donors for xenotransplantation (Girasole, 2014). Pig farming poses fewer logistical and ethical problems because they mature quickly, produce large litters, and can be raised to high standards in sterile conditions (Werner, n.d.); this makes the use of pigs more profitable (Magdalena Hryhorowicz, 2017). Using pigs presents a complication because they have a much shorter gestation period than humans (1/3 that of humans), meaning human cells would have to be inserted depending on the developmental stage of the fetal pig (Knapton, 2017). ; the attempts were successful, with the human cell able to grow for 3 to 4 weeks (Knapton, 2017). On top of all this, the variety of pig breeds means that an organ could be tailored to a specific patient (Magdalena Hryhorowicz, 2017), reducing the risk of rejection. In this essay, I will explore xenotransplantation as a technology, examining its flaws, ethical issues, and any alternatives that can be used instead of or alongside this leading technology. The experiments continued until the 1980s; there were some "successes", such as the survival for 9 months of a chimpanzee kidney in a human being (the other 12 out of 13 patients died within 2 months) under the direction of surgeon Keith Reemtsma in 1964 (Heggie, 2016). The technology gained popularity in 1983 when a baby (Baby Fae) died after an unsuccessful baboon heart transplant attempt (McNamee, 2014). It was the fear of rejection and PERVs (something I'll talk about later) that shut down the technology completely in the late 1990s. Xenotransplantation can seem like fiction (like HG Wells' classic novel The Island of Dr Moreau), but it has been attempted since the 17th century (Heggie, 2016), and heart valve transplants are currently used (Griffin, 2017). Ian McConnell, Emeritus Professor of Veterinary Science at the University of Cambridge, said that "there are several medical procedures using pig tissue, such as heart valves in cardiac surgery, pancreatic cells producing insulin to correct diabetes in humans and corneal transplants which have been used safely in humans for many years”; demonstrating that xenotransplantation is a, 2016)