Xenotransplantation could be used to treat severe burns, addressing the problem of closure and coverage, with the best source currently being fresh cadaver allografts, of which there is a great shortage (Ge, et al., 2010). A promising breakthrough has been the use of genetically modified pig skin CTLA4Ig (cytotoxic immunoglobulin T-lymphocyte-associated antigen 4) as a wound dressing using Ad5F35 as a viral delivery vector (Ge, et al., 2010). However, acute immune rejection causes the survival of this skin to always be less than 14 days (not long enough to meet needs); therefore, current methods such as autologous split-thickness skin grafts (skin layers of dermis and epidermis taken from part of a patient and transplanted onto the burn), cultured epidermal sheets, artificial materials, and cultured cell matrices (Ge, et al., 2010). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Livers were designed for xenotransplantation that can produce antibodies against host immune cells, this “gelatinous dewdrop” protects pancreatic islet cells from the host's immune system (Reardon, 2015). This 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 are very promising, being much easier to transplant than solid organs (González, 2012). This could treat diabetes without the need for immunosuppression (María Jorqui Azofra, 2012). Although more life-threatening in case of failure (15% of heart transplant patients die within one month of surgery (Strachan, 2015)), heart xenografts have been shown to be more successful than other organs. One 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 was not replacing the baboon's own heart (Reardon, 2015). Kidney transplants appear more promising (Reardon, 2015); with an average waiting time of 3 years for kidneys, the demand is high (Strachan, 2015). The only alternative is the invasive and intense treatment that is dialysis; this takes time out of your life, limits your fluid intake, and increases your risk of heart attack or stroke (Strachan, 2015). Kidney xenografts have been relatively successful, with one transplanted kidney functioning in a baboon for 4 months (Reardon, 2015). When I spoke to the leading xenotransplant researcher, Dr. David Cooper, he told me: “I believe that the first patients to participate in a clinical trial will be those waiting for a kidney transplant. If the trial fails, the pig kidney can be removed and the patient can return to dialysis (if this is still possible).” (Cooper, 2018). This shows that failure of a kidney xenograft would not always be fatal, making it more suitable for clinical trials. It is hoped that a multitude of organs and tissues can be used for xenotransplantation. The cornea, for example, has already been approved for marketing in China in April 2015 (Reardon, 2015). The lung is another highly requested organ for which xenotransplantation could represent the solution; however, the lungs' extensive network of blood vessels has proven “extremely difficult to transplant,” increasing the possibility of contact with donor and host blood, which increases the risk of rejection (Reardon, 2015). An intensive breeding farm was designed forproduce 1,000 pig lungs a year (Mountain, 2015), this could help alleviate the shortage which resulted in 56 deaths in the UK in 2014 alone (Strachan, 2015). Lungs are often unsuitable for transplantation (23% are not offered), with half of those suffering from cystic fibrosis (a genetic condition that affects the functioning of the lungs) needing a lung transplant as adults; the shortage means that 1/3 of these individuals will die before this transplant can happen (Strachan, 2015). Lung xenografts are the most difficult organ to transplant, requiring the modification of 12 genes to make it suitable; by 2014, United Therapeutics had successfully removed 6 of these genes (McNamee, 2014). The source of these organs would most likely be domestic pigs, Sus scrofa domestica (Magdalena Hryhorowicz, 2017). Pigs would be better suited for a number of reasons, primarily because pigs have organs of similar size and function to humans (Griffin, 2017). Although they do not constitute a perfect genetic match, primates, which represent the alternative (best genetic match), have organs that are too small and therefore not suitable donors for xenotransplantations (Girasole, 2014). Pig farming poses fewer logistical and ethical problems as 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 convenient (Magdalena Hryhorowicz, 2017). There is a complication in using pigs, as they have a much shorter gestation period than humans (1/3 that of humans), which means that human cells would have to be inserted at the stage of development of the pig's fetus (Knapton, 2017). ; attempts to do so have been successful, allowing the human cell to develop for 3-4 weeks (Knapton, 2017). In addition to all this, the variety of pig breeds means that an organ can be matched 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 important technology. The experiments continued into the 1980s; there have been some "successes", such as the 9-month survival of a chimpanzee kidney in a human (the other 12 of 13 patients died within 2 months) under the guidance of surgeon Keith Reemtsma in 1964 (Heggie, 2016) . The technology gained publicity in 1983, when a child (Baby Fae) died after a failed baboon heart transplant attempt (McNamee, 2014). It was the fear of rejection and PERVs (something I'll talk about later), that stopped the technology completely in the late 1990s. Xenotransplantation may seem like something from fiction (such as H.G. Wells' classic novel, The Island of Doctor Moreau), but it has been attempted since the 17th century (Heggie, 2016), with heart valve transplants being used today ( Griffin, 2017). Ian McConnell, emeritus professor of veterinary science at the University of Cambridge, said that "there are several medical procedures that use pig tissue such as heart valves in heart surgery, pancreatic cells that produce insulin to correct diabetes in man and corneal transplants that have been used safely in humans for many years"; demonstrating that xenotransplantation is a very current technology. For larger organs (such as the kidneys and the heart) new problems arise; solid organs from primates to humans in the 1960s, with the rejection of organs by the human immune system (Reardon, 2015, surgeons such as Dr. Samuel)., 2016)