Success of First Pig-to-Human Kidney Proves Promising for Addressing Organ Shortage
Maggie Walsh ‘23
There exists a great disparity between the number of organs viable for donation and the number needed by critically-ill patients, resulting in a national waiting list of over 100,000 vulnerable individuals. Despite widespread efforts towards encouraging people to register as organ donors, human organs alone will likely never be able to meet this extensive demand. Consequently, for over 50 years researchers have considered xenotransplantation, which is the transplantation of organs between species, to address the organ shortage. If incorporated in mainstream treatment, xenotransplantation could provide an unlimited supply of organs, making researchers understandably eager to explore this procedure.
The mid-20th century marked the beginnings of xenotransplantations, consisting of transferring organs from non-human primates to primates. In addition to lacking any lasting success, there was much public uproar surrounding the ethics of doing so, and scientists quickly turned their attention towards pigs. Pigs are remarkably anatomically similar to humans, and humans are already experts in breeding pigs, thus making them the ideal subject for human-focused xenotransplantations. The first attempts of pig-to-primate xenotransplantation resulted in hyperacute rejection by the immune system and an immediate blackening of the transplanted organ. These rejections were largely due to a sugar present in pig organs known as alpha gal. Due to recent developments in genetic engineering, scientists have since been able to disable the gene that codes for this sugar, and subsequent xenotransplantations of the early 2000s into non-human primates have been successful. While the success of xenotransplantations into non-human primates is remarkable, it fails to address the pressing issue at hand; about 17 people die each day as they wait for an organ transplant. Recent strides towards addressing this issue were made in late September with the occurrence of an atypical kidney transplant.
This kidney transplant marked the first pig-to-human xenotransplantation. In a two hour operation, a team of surgeons, led by Dr. Robert Montgemory, attached a pig kidney to blood vessels in the upper leg of the recipient - a brain dead woman kept alive on a ventilator whose family agreed to her body being utilized for experimental purposes, honoring her wish of being donated for others’ benefit. The kidney was left outside of her body to allow for close monitoring, and it was seen to function normally for 54 hours, producing expected levels of urine and creatinine, with no signs of rejection. Though the study was halted after 54 hours due to ethical concerns behind artificially maintaining the life of a brain-dead woman, these 2.25 days of success mark a significant step in the path towards integrating xenotransplantation into mainstream treatment.
Before xenotransplantations can be made common practice, researchers will first have to conduct month- and year-long studies in which pig organs are fully inserted into the human body and long-term effects are observed. From there, safety concerns must be addressed and FDA approval will be required. Though we are still in the early stages of pig-to-human xenotransplantations, many questions and concerns are already arising, including the costs associated with the surgery, the ethics regarding mass-producing pigs for their organs, and the physician training needed to safely perform such procedures. These, along with many more concerns, will need to be addressed before the benefits are reaped and lives are saved. In the meantime, this study should leave us with optimism and an appreciation that pigs may be the long-awaited solution to our organ shortage. As Dr. Montgomery phrases it, this surgery “should be celebrated - not as the end of the road, but as the beginning.”
Sources:
https://nyulangone.org/news/progress-xenotransplantation-opens-door-new-supply-critically-needed-organs
https://www.organdonor.gov/learn/organ-donation-statisti
https://apnews.com/article/animal-human-organ-transplants-d85675ea17379e93201fc16b18577c35cs