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A surgical team at NYU Langone Health last month achieved a stunning medical feat: attaching the kidney of a pig to a human body, and watching it get to work. This animal-to-human transplant is called xenotransplantation.
The kidney wasn’t implanted inside the body; rather, the scientists attached it to the patient via the blood vessels in their upper leg and placed it outside the body. This allowed them to take tissue samples more easily and observe the organ as it worked. Plus, in the case of organ rejection, it could be removed quickly.
One hurdle scientists have faced in the quest to make xenotransplantation possible is the components within. With pigs, in particular, a sugar in the animal’s cells called alpha-gal is foreign to our system, and this would cause an immediate immune system attack and organ rejection.
To overcome this, the kidney used in the surgery came from a pig who was genetically modified by
Revivicor, a subsidiary of United Therapeutics, to remove this sugar. This also removes the risk of a harmful organ rejection in the patient.
The New York Times also reports that, as added precaution, the surgeons also transplanted the pig’s thymus into the patient. This is a small organ that produces immune cells, reducing the chances of rejection.
When attached during the procedure, the kidney proceeded to function as normal, carrying out its usual functions: waste filtration and urine production. It didn’t trigger any rejection, which the team was “worried about,” according to Dr Robert Montgomery, who led the team.
There are concerns that rejection might occur long after a transplant, as is the case “even when you’re not trying to cross species barriers,” Dr Dorry Segev, a professor of transplant surgery who wasn’t on the team, tells
Live Science. The “longevity” will therefore need to be assessed further before developing the tech, but it looks promising so far.
The Associated Press reports that more than 90,000 people in the US are currently on the waitlist for a kidney transplant, with around 12 deaths daily while waiting.
With further developments and rigorous testing regarding safety, this number could dwindle thanks to the new advancement in medical tech.
But, of course, ethics come into question. The Hastings Center is reported to be involved in developing ethical and policy guidelines for the first cross-species transplant clinical trials. However, as Karen Maschke, a research scholar at the Hastings Center, puts it, “should we be doing this just because we can?”
The experimental surgery was conducted in a brain-dead patient whose family had granted permission for the procedure on their behalf. The patient had previously consented to their organs being donated. In total, the process took 54 hours.
[via
Live Science, image via
Shutterstock]