Patients in China and the US have received pig organ transplants, opening an ethical can of worms
- Two milestone surgeries transplanting pig organs into human patients have shone a light on xenotransplantation
- But the practice raises ethical concerns, including possible virus transmission, which must be addressed
The transplant of pig organs into human patients made global headlines last week with two milestone achievements in the field, but ethical considerations like virus transmission may still present a barrier to it becoming common practice.
The first feat involved Chinese doctors transplanting a pig’s liver into a patient who had suffered brain death.
“One of the potential benefits of xenotransplantation is the limitless graft supply that would help a lot of patients with urgent need for transplant,” said Albert Chan Chi-yan, a clinical professor at the University of Hong Kong and director of Queen Mary Hospital’s Liver Transplant Centre.
The limitless supply of organs could bring hope to hundreds of thousands of patients around the world waiting for their names to get to the top of transplant lists amid global shortages.
But ethical concerns could prove a fly in the ointment.
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“[One concern is] the risk of disease transmission from animal species to human,” Chan said.
Pigs used for human transplants are typically bred in specialised facilities to ensure they are pathogen-free. However, this has not always been successful.
Although the “potential benefits are considerable” the possibility of transmitting infectious agents is still a major concern, especially as some may not be detected before transplant, according to the US Food and Drug Administration (FDA).
“Tolerance to the new organ and risk of acute rejection are other problems to overcome in this field,” Chan said.
Animals used in xenotransplantation are typically genetically modified to reduce the risk of organ rejection. Pigs can also be genetically modified to add in human genes to ensure the organ is a better fit.
The kidney used in the US transplant last week came from a pig with a record 69 gene edits, according to a report by Nature.
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There may also be concerns about “the psychological impact to the organ recipient” after surgery, Chan said.
According to FDA guidelines, the transplant of animal organs into humans should be limited to patients with “serious or life-threatening diseases” for whom alternative therapies may not be available.
Despite the ethical concerns, a report on a 2018 meeting in China which included the World Health Organization stated that xenotransplantation “could bridge the gap between demand for, and supply of, human organs for transplantation”.
While xenotransplantation is still in its infancy in practical terms, Chan said there was still more work to do.
“Future research should focus on how genetic editing could help to modify the animal organ to become entirely suitable and acceptable for human application,” he said.
