Xenotransplants As A Counteraction To Organ Shortage

Every day people with life-threatening illnesses face a similar problem in the healthcare industry. The demand for organs is insatiable, and supply never meets the demand. There simply aren’t enough organs being donated to keep up with the amount of people who desperately need them. Due to this, there have been movements to research alternatives to organ donation. One such alternative is xenotransplants, a procedure in which an organ may be grown in one animal, such as an ape, and then transplanted into an animal of another species, like a human. Martine Rothblatt, CEO of United Therapeutics Corporation, a biotechnology company that funds various studies on xenotransplantation, on the topic of xenotransplantation ethics, says, “I believe the towering fact is that millions of people a year die worldwide from end‐stage organ disease. Only about 1% of those patients can be saved with brain‐dead human organ donations, and only in a few advanced economies” (Rothblatt). Xenotransplantation is a very controversial topic, particularly when considering animal rights. Additionally, “sophisticated” xenotransplants started in the 1960s (Anderson 205), but they still haven’t perfected it and erased all the complications and failures that can occur. When dealing with the organ shortage, xenotransplants are not close to effectively fighting the shortage. More research needs to be done to counteract complications, and consideration towards the test animals needs and rights are necessary before xenotransplantation can be ethically and scientifically sound as an alternative to organ donation.

A common issue that arises with the ethics of xenotransplantation is the risk of not meeting the rights of the animals involved, and that includes humans! While the animals that are tested on/used cannot give consent, much less informed consent, that is something many people can overlook when considering animals as lesser beings than humans. Speciesism is commonly referenced in arguing the ethics of xenotransplants. It is important to consider an animals sentience, instead of selecting animals from a speciesist standpoint (Anderson 207). Xenotransplants started out using primates as subjects, due to the genetic similarities. Now, pigs are more commonly used. Some say it is because of the higher risk of extinction with slow-breeding primates, and comparable organ sizes, another reason is that pigs are less human-like. Additionally, pigs are already killed in high numbers for their meat (Ravelingien 235). Some compare speciesism to racism, noting that treating animals differently due to kinship is prejudice. Using cognitive abilities to decide who better deserves to be used moves into a morally grey area, as humans may also present lower cognitive abilities, such as infants or the mentally impaired (Ravelingien 237). Some disagree with the outcry for animal rights, referencing the pigs killed for their meat, and argue that if it’s okay to kill them to feed people, it should be okay to kill them to treat people, too. They can be treated with care approved by veterinarians and still be used for xenotransplants. (Rothblatt). However, human rights could also be at risk. Still being in what some would consider early research, there is a risk that doctors participating in research may think of their patient as a research subject rather than a person first and foremost, and mistreat them like in the Tuskegee Syphilis study (Anderson 206). Additionally, people who cannot afford allotransplants may agree to xenotransplants because of this fact (Anderson 207).

Xenotransplants come with various complications and health implications, some unique to working with different species. While immunosuppressive therapies have been improved through the years, research is still not at a point where xenotransplants can be considered long-term (Anderson 205). Even so, some believe that xenotransplants can prolong a patient’s life while they wait for a human organ (Servick). Even if the organ is accepted, there is a new risk of “viral mosaics” (Anderson 205). The link between primates and humans is especially easy for the spreading of a virus, although there is also a high risk of transmission with pigs (Ravelingien 236). To contain this risk, one suggestion has been that a xenograft registry may be implemented to track not only xenograft survivors but also their friends, lovers, and family. Outcry over this suggestion claims that it is an invasion of privacy. Scientists can’t reach a consensus on how to monitor it without invading patient privacy, and the American Society of Transplant Physicians aren’t satisfied with the trail regulations, given the infectious agents risking zoonotic disease (Anderson 206). Psychosocial effects should also be considered, when patients consider having a foreign organ from another species in them, they may feel their humanity is at risk. However, a Teran-Escandon et al study didn’t find preconceived notions of altered autonomy posed negative effects post-surgery (Anderson 207). As for the risk of zoonotic disease, immunosuppressive drugs would be needed to prevent rejection, and such intensive therapy would leave patients extremely vulnerable to infections (Servick). Others disagree, claiming that the low likelihood of for zoonotic disease transmission is not enough to ban xenotransplants, which would only injure those who need a transplant (Rothblatt).

The risk of organ rejection has been lowered through research, and further reduction of rejection occurrences are likely to occur with more research. The Balden et al study, referenced by Emanuele Cozzi, a clinical immunologist, in his article “On the Road to Clinical Xenotransplantation”, found that an immunosuppressive therapy allowed a renal xenograft in a primate to last 90 days, much higher than lung or liver xenotransplants (Cozzi 58). It is believed that the underlying causes of pig to primate xenotransplant rejections have been found, allowing for strategies to be developed to reduce rejections. Additionally, scientists have started working on engineering special pigs for xenotransplantation. With these biomolecular strategies, pig-primate rejection barriers have begun to be addressed, bringing science closer to allowing pig-human compatibility (Cozzi 59). Research into gene edits and donor antigen induction is being done, with the intent that success would mean that xenografts could be equal to allografts in longevity. Donor antigen induction would result in immunological chimerism, called microchimerism, allowing the patient to be “weaned off of immunosuppressants,’ a feat rarely achieved by allotransplants due to lack of time for planning. (Rothblatt). Transplant immunologist David Cooper says, “better immunosuppressant drug regimens and a wealth of new gene-edited pig varieties have changed the equation.” With these advances, scientists can now target parts of pig cells that trigger an immune response, removing that potential of rejection and removing viral sequences in their genes while introducing human genes (Servick).

Xenotransplants are presented as one way to balance out the organ shortage compared to organ demand. It is, however, widely controversial for various reasons, including the risk of zoonotic diseases spreading from the subject animal to the human patient, and organ rejection. For the risk of rejection, various tactics have been implemented, including efforts to increase compatibility between pig organs and human organs (using a primate bridge), and immunosuppressive therapies. Animal rights have been questioned, as they cannot consent and the selection of pigs as a target species being based on their less human-like traits, although the widespread acceptance of slaughtering animals for meat have been used to counteract animal rights abuse claims. Human rights are also brought into question, considering the Tuskegee syphilis study as reason to fear mistreatment of patients when physicians consider their patients research subjects. It’s important to know that xenotransplantation is not the only alternative to organ shortages. Other alternatives include giving donors a financial incentive, and using “presumed consent”, assuming a dying person consents to having their organs donated unless they state otherwise. These two tactics have proven in the past to give little increase to organ donation (Anderson 205). However, another, perhaps more successful, alternative could be therapeutic cloning. While also controversial, therapeutic cloning may not bring about so many complications. Xenotransplantation is a long way from being perfected, and there is a worry that money put into xenotransplantation means that money isn’t put into other research that may make breakthroughs sooner.

Bibliography

1. Anderson, M. “Xenotransplantation: A Bioethical Evaluation.” Journal of Medical Ethics, vol. 32, no. 4, 2006, pp. 205–208.
2. Cozzi, Emanuele. “On the Road to Clinical Xenotransplantation.” Transplant Immunology, vol. 21, no. 2, June 2009, pp. 57–59. EBSCOhost, doi:10.1016/j.trim.2009.05.002.
3. Ravelingien, An. “Use of Pigs for Xenotransplantation: The Speciesism by Proxy Syndrome.” Xenotransplantation, vol. 12, no. 3, May 2005, pp. 235–239. EBSCOhost, doi:10.1111/j.1399-3089.2005.00215.x.
4. Rothblatt, Martine. “A Personal Perspective on the Science, Ethics, and Commercialization of Xenotransplantation.” Xenotransplantation, vol. 25, no. 3, May 2018, p. 1. EBSCOhost, doi:10.1111/xen.12414.
5. Servick, Kelly. “Xenotransplant Advances May Prompt Human Trials.” Science (New York, N.y.), vol. 357, no. 6358, 2017, pp. 1338–1338.