By David Lu
Would you consider replacing your kidney with that of a pig’s? While this question seems purely hypothetical, recent progressions in biomedical science have made it increasingly realistic. Human organs are in great demand, yet there is a supply shortage. Due to this, scientists have been experimenting with the usage of organs from animals in humans, otherwise known as xenotransplantation. Xenotransplantation is mainly backed by hopes of combating the shortage of organs.
Modern xenotransplantation is still a new field of medicine that is ongoing experimentation. However, the concept itself has been around for centuries. The idea of cross-species transplantation first dates back to 1667, where the idea of blood xenotransfusion was considered. The first experiments were conducted in the early 1900s but were all mostly unsuccessful. The first successful xenotransplantation was in 1964 when a chimpanzee kidney was transplanted in a human who survived for nine and a half months with the foreign kidney. The operation served as proof that xenotransplantation is feasible.
Currently, for xenotransplantation to be practical and consistent, researchers are looking to improve interactions between the organ and the human immune system/blood by performing modifications. Researchers have already been modifying organ genetics using a genetic modification technology called CRISPR. These genome modifications are needed because organs of other species are incredibly different from human organs. Genetic modification is used to decrease that gap and reduce the risk of viral infections.
The animals of choice for use in xenotransplantation are pigs. Pigs are used instead of primates because primates present a higher risk of disease. Pigs are already raised as livestock, so they are readily accessible for use in xenotransplantation. Lastly, pig organs are of similar size to humans, making pig organs quite compatible with humans.
While xenotransplantation seems a perfect substitute for human organs, there has been a host of issues that surround the idea of using animal organs in a human. First is the issue concerning the welfare of animal donors. The animals will all inevitably be killed for their organs. Furthermore, animals used for xenotransplantation will not be kept in the most hospitable environment, as they will be kept in a manner akin to that of laboratory animals. Another issue that arises is whether the genetic engineering used in xenotransplantation is ethical or not.
Along with these concerns, there is also the major issue of organ rejection. Rejection is when the organ recipient’s immune system attacks the foreign organ as if it were an infection. In xenotransplantation, rejection can be so severe as to be hyperacute, a type of rejection where the immune system destroys the organ. To combat this, scientists have tried breeding genetically altered pigs. These pigs have proteins similar to that of humans, which makes it less likely for the immune system to react harshly. As more and more techniques are developed to combat rejection, the feasibility of practical xenotransplantation use grows.
Approximately 10 people die each day waiting for an organ. With numbers like these, the medical necessity of operations such as xenotransplantations are increasing. Just like how Daedalus xenotransplanted bird wings onto Icarus, allowing for him to soar in the open sky, xenotransplantation is opening new opportunities for many people, letting them fly higher than ever. However, as the medicine progresses, one can only ask:
“Are we flying too close to the sun?”
Sources
Cooper, D. K.C., Ekser, B., & Tector, A. J. (2015). A brief history of clinical xenotransplantation. International Journal of Surgery, 23, 205-210. https://doi.org/10.1016/j.ijsu.2015.06.060
Griesemer, A. (n.d.). How Xenotransplantation Works. Retrieved October 24, 2021, from https://healthmatters.nyp.org/how-xenotransplantation-works/
Lu, T., Yang, B., Wang, R., & Qin, C. (2020). Xenotransplantation: Current Status in Preclinical Research. Frontiers in Immunology, 10. https://doi.org/10.3389/fimmu.2019.03060
Rollin, B. E. (2020). Ethical and societal issues occasioned by xenotransplantation. Animals, 10(9), 1695. https://doi.org/10.3390/ani10091695
Tena, A. (2015, November 2). Xenotransplantation: Can pigs save human lives? Retrieved October 24, 2021, from https://sitn.hms.harvard.edu/flash/2015/xenotransplantation-can-pigs-save-human-lives/
Xenotransplantation. (2021, March 3). Retrieved October 24, 2021, from https://www.fda.gov/vaccines-blood-biologics/xenotransplantation