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Transcript of Xenotransplantation
Benefits of Xenotransplantation
Xenotransplantation is beneficial in many ways; both medically and economically.
By using animals, the risk for rejection becomes greater. But the animals can be genetically altered to prevent the immune system from identifying the organ as foreign and attacking it. (Sharma, 2010)
Animals, such as the pig, are anatomically similar to humans. The size of their organs match the size of a human's organs so they may be used as a transplant.
The demand for organ donations is substantially higher than the supply. (Sharma, 2010) Approximately 10 people die every day waiting for an available organ.
Unlike humans, animals reproduce quicker. Pigs in particular breed very quickly and have larger litters. This will greatly increase the amount of organs for transplants to meet the demand. (Sharma, 2010)
Animals are also able to be monitored to ensure that the animal's organs are healthy and undamaged.
Mehra, Jo-bess, Heather, sarah, Jasmine
What Is Xenotransplantation?
Xenotransplantation is defined as the transplantation of living cells, tissues or organs from one species to another. Humans have developed this type of surgical procedure in hope to further supply organs as there is a shortage to the amount of organs available compared to the amount needed.
What changes do you believe need to happen in order to shift xenotransplantation’s commodity based approach to transplanting organs ?
In your opinion what is the most dangerous risk xenotransplantion poses?
Is it ever okay to take advantage of animals and a group of people for a short period of time, even if it is the only way to save millions of people? Use examples from xenotransplantation to back-up your opinion.
At which stage of scientific development is it okay to test cross species organ transplants on humans?
Which Animals are used in xenotransplantation?
How would you react to having xenotransplantational surgery? Would it bother you that the transplant is from an animal?
Issues Scientists must Overcome
In order for successful cross species organ transplantation to occur, several issues must be overcome: (Nhmrc Government)
The body could contract the virus PERVs (porcine endogenous retrovirus)
There is a higher likelihood of infections and diseases when dealing with cross species transplantation
The body has a heightened immune response due to the HLA protein which increases the chance of rejection
Increase in inflammation and coagulation
The organ or valve also deteriorates at a faster rate
the future of xenotransplantation
Sci-Show on Xenotransplantation
Scientists at the National Institute of Health, used genetically engineered pig hearts and transplanted them into baby baboons
Scientists took out genes that would make organ rejection more likely while inserting human characteristics
Scientists further used targeted immunosuppressants to eliminate organ rejection
During the surgery scientists used a procedure in which they kept the actual baboon's heart in place and connected the transplanted heart into the circulatory system in the baboon's abdomen
Procedures for Eliminating Virus infection
Researchers at Harvard have used the technique of CRISPR to essentially remove the PERVs virus from the pig's genome making a human recipient less likely to contract the virus after surgery
(Wyss Institute at Harvard)
Although xenotransplantation is still a work in progress, there are common procedures, such as using pig heart valves to replace human ones, that are often put into practice.
Xenotransplantation is simply used as an alternative method to using human donors. It can have multiple uses such as;
Organ Transplants: replacing diseased and non-functioning organs (i.e heart or kidneys)
Cell Transplants: replacing damaged or destroyed cells from diseases (such as Parkinson's or Huntington's disease)
Tissue Transplants: providing skin grafts, bone transplants or even cornea replacements
Bridge to Transplants: they can even be used as a temporary fix while waiting for a donor match or human donor transplant
Learning goals and Success Criteria
Students will attain knowledge on the purpose, history, and future of xenotransplantation
Students will be exposed to both the positive and negative ethical implications of xenotransplantation
Students will be given the tools and knowledge to formulate a personal opinion on xenotransplantation
Why monkeys Are not used in organ donation
Pigs as organ donors
Monkeys can easily transmit disease to humans
Monkeys are thought to be too similar to humans; many people think it would be inhumane for them to have their organs harvested
Monkeys don't reproduce at a fast enough rate
Pigs are already a mass produced animal due to food production
Pigs can be kept away from disease limiting their risk of infection and transmission
Pigs share the same sized organs as humans, making cross-species organ transplants possible in the future
Genetic engineering could allow for virtually no risk of organ rejection
History and types of transplantation rejection
In 1944, Peter Medawar discovered that transplanted tissue or organs caused the immune system of the recipient to react. Usually, the immune response protects us from disease- causing pathogens, such as bacteria and viruses.
The problem with transplantation is that the immune system of the recipient recognizes the organ as foreign and attacks the new tissue. This leads to transplant rejection and failure.
There are three types of transplant rejection:
• Hyperacute rejection: occurs rapidly, often before the surgery is complete, as pre-existing antibodies from the immune system react with the donor tissue.
• Acute rejection:–occurs in first weeks or months after surgery as an immune system response develops.
• Chronic rejection: occurs gradually over several years after surgery.
Important Historical moments for xenotransplantation
"Health Canada- Xenotransplantation." 17 Jan. 2006. Web. 17 Jan. 2016. <http://www.hc-sc.gc.ca/sr-sr/tech/biotech/about-apropos/xeno-eng.php>.
"U.S. Food and Drug Administration." 02 Apr. 2010. Web. 17 Jan. 2016. <http://www.fda.gov/BiologicsBloodVaccines/Xenotransplantation/>.
"Xenotransplantation | Biotech Learning Hub." 7 Dec. 2011. Web. 18 Jan. 2016. <http://biotechlearn.org.nz/themes/xenotransplantation_and_organ_donation/xenotransplantation>.
"Xenotransplantation." 13 Jan. 2016. Web. 17 Jan. 2016. <https://en.wikipedia.org/wiki/Xenotransplantation>.
Samdani, Tushar. "Xenotransplantation." : Overview, Choosing the Donor Species, Immunologic Barriers to. 9 Sept. 2014. Web. 18 Jan. 2016. <http://emedicine.medscape.com/article/432418-overview>.
De Louraille, Claire. "TransplantInformers." Xenotransplantation Basics: No, It's Not a Warrior Princess. 25 Apr. 2013. Web. 18 Jan. 2016. <http://transplantinformers.com/2013/04/25/xenotransplantation-basics-no-its-not-a-warrior-princess/>.
Dooldeniya, M. D., and A. N. Warrens. "Xenotransplantation: Where Are We Today?" Journal of the Royal Society of Medicine. The Royal Society of Medicine. Web. 19 Jan. 2016.
"XENOTRANSPLANTATION: The Benefits and Risks of Special Organ Transplantation." XENOTRANSPLANTATION: The Benefits and Risks of Special Organ Transplantation. Web. 19 Jan. 2016.
Sharma, Arun. “Xenotransplantation: Weighing The Risks and Benefits of a Controversial Procedure. Penn Bioethics Journal Journal 6.2 (2010): 25. Advanced Placement Source. Web. 19 Jan. 2016.
Ekser, Burcin, et al. “Xenotransplantation Of Solid Organs In The Pig-To-Primate Model.” Transplant Immunology 21.2 (2009): 87. Advanced Placement Source. Web. 19 Jan. 2016.
Boneva, Roumiana S., Thomas M. Folks, and Louisa E. Chapman. "Infectious Disease Issues in Xenotransplantation." Clinical Microbiology Reviews. American Society for Microbiology, 14 Jan. 2001. Web. 19 Jan. 2016. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC88959/>.
Dooldeniya, M. D., and A. N. Warrens. "Xenotransplantation: Where Are We Today?" Journal of the Royal Society of Medicine. The Royal Society of Medicine, Mar. 2003. Web. 19 Jan. 2016. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC539416/>.
"Heart Valve Replacement." St Jude Medical. Web. 19 Jan. 2016. <https://health.sjm.com/heart-valve-answers/treatment-options/heart-valve-replacement>.
"Do Primates Have Similar Blood Types to Humans?" › Ask an Expert (ABC Science). 7 Apr. 2010. Web. 19 Jan. 2016. <http://www.abc.net.au/science/articles/2010/04/07/2866275.htm>.
"Apecsec.org." Apecsecorg. Web. 19 Jan. 2016.
"Xenotransplants." Xenotransplants. Web. 19 Jan. 2016.
"Pros and Cons of Xenotransplantation - Vision Launch." Vision Launch. 2015. Web. 19 Jan. 2016.
"7 Vital Pros and Cons of Xenotransplantation | NLCATP.org." NLCATPorg. Web. 19 Jan. 2016.
"Removing 62 Barriers to Pig-to-human Organ Transplant in One Fell Swoop." : Wyss Institute at Harvard. Web. 19 Jan. 2016.
Cowan, Peter J., David K.C. Cooper, and Anthony J.F. D’Apice. "KIDNEY XENOTRANSPLANTATION." Kidney International. U.S. National Library of Medicine. Web. 10 Jan. 2016.
Dillard-Wright, David B. "Life, Transferable: Questioning the Commodity-Based Approach to Transplantation Ethics." Society & Animals 20.2 (2012): 138-53. Print.
Ekser, Burcin, Paolo Rigotti, Bruno Gridelli, and David K.c. Cooper. "Xenotransplantation of Solid Organs in the Pig-to-primate Model." Transplant Immunology 21.2 (2009): 87-92. Print.
"Frequently Asked Questions about Xenotransplantation." Frequently Asked Questions about Xenotransplantation. Nhmrc Government. Web. 19 Jan. 2016.
Mohiuddin, Muhammad M., Avneesh K. Singh, Philip C. Corcoran, Robert F. Hoyt, Marvin L. Thomas, David Ayares, and Keith A. Horvath. "Genetically Engineered Pigs and Target-specific Immunomodulation Provide Significant Graft Survival and Hope for Clinical Cardiac Xenotransplantation." The Journal of Thoracic and Cardiovascular Surgery 148.3 (2014): 1106-114. Print.
Ring, J. "Perspectives of Atopic Eczema in the Third Millennium." The Atopy Syndrome in the Third Millennium Current Problems in Dermatology (1999): 194-204. Print.
"Pigs' Hearts Transplanted into Baboon Hosts Remain Viable More than a Year." ScienceDaily. American Association for Thoracic Surgery, Aug. 2014. Web. 17 Jan. 2016.
"Xenotransplantation: Using Pigs as Organ and Tissue Donors for Humans." The Conversation. Web. 10 Jan. 2016.
Sarah Knapton. "China Shocks World by Genetically Engineering Human Embryos." The Telegraph. Telegraph Media Group, Apr. 2015. Web. 17 Jan. 2016.
"Xenotransplantation: Using Pigs as Organ and Tissue Donors for Humans." Web. 07 Jan. 2016.
Should xenotransplantation be performed on people of all ages? Even newborn babies?
Was it smart to ban xenotransplantaion? Should the ban still remain? Why?
Why Does It Work?
Currently, doctors are able to regularly perform organ transplants for the heart, pancreas, kidneys, liver, lungs and even the intestines
To find an organ donor, one of the most important qualities that is looked for is that the blood types match and are viable as a donor to the patient
With xenotransplantation, the animals that are used and experimented with are usually pigs and types of monkeys
Pigs have blood types A and O, while monkeys have more complex blood types that are still comparable to the human ABO system
O is the universal blood donor so an organ that has type O blood would be available to all blood types
Current And Future Xenotransplantations
Xenotransplantation is still mostly very experimental
The most common practical procedure is replacing human heart valves with pig heart valves
This works because they function similarly and once it is removed from the animal, it is chemically treated to prevent the immune system from rejecting it
In theory, this could also work for complete organs, but doctors have still been unable to successfully perform an organ xenotransplantation
This is due to the fact that there are many factors to consider and heart valves are only a small part of an organ so they are much easier to transplant
The first immunosuppressive drugs were identified in the early 1960s. These drugs allowed for successful transplants (pancreas, liver and heart) from to human to human.
Doctors wondered if these drugs could also be used to prevent the rejection of xenotransplants. In 1963, Dr Thomas Starzl transplanted kidneys from baboons into six human recipients in Denver, US.
The patients survived between 19–98 days.
Over the following decades, animal to human organ transplants were attempted, but success rates were low compared to human to human transplants, even with immunosuppression.
In 1997, there was a worldwide ban on xenotransplantation. Concerns emerged about a pig virus called Porcine Endogenous Retrovirus (PERV) being transmitted to humans.
However many studies took place to uncover the truth about the harm of PERV. It was concluded that the virus could not produce infectious particles in other species.
Some countries, including the US, UK and New Zealand, are now allowing xenotransplantation research to continue, but it’s based on the case of the situation.
It should be noted that the first successful human to human transplant in 1954 was performed by Joseph Murray.
He was able to transplant a kidney between two identical twin brothers. Since they were genetically identical, the immune system of the recipient did not attack the foreign kidney and rejection was prevented.
Is a human life worth more than an animal's? Is it morally acceptable to harvest their organs to save human lives?
Negative Aspects Of Xenotransplantation
Procedures will have to be done multiple times throughout one's life
The body could reject the transplant
Viruses can be transferred between animals and humans
Many people are against xenotransplantation because of religious beliefs
What do you predict for the future of xenotransplantation?