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The heart of a baboon, the eye of a newt, and the skin of a pig, is not just a recipe
for witchcraft anymore. Some might be part of the future of organ transplantation.
Hey everyone welcome to DNews, I'm Trace. For more than two years, a baboon at a research
institute in Maryland survived with the heart of a pig in its abdomen! Two. YEARS. The previous
record for implanting an organ from another species was about 500 days, but this heart
made it to 945 days!
Cross-species transplantation is called xenotransplantation. It might seem like a Frankensteinian fiction,
but it's been done. A baboon heart was transplanted into a newborn baby with a heart problem (she
lived almost three weeks), burn patients sometimes accept skin grafts from pigs, and Parkinson's
patients have received neurons from our p-p-p-porky pals as well. It would seem we have an unending
supply of organs from animals grown for food, but cross-species transplants -- though hypothesized
for centuries, are JUST becoming a reality… if scientists can get it to work properly…
Firstly, we needed to pick a species. The natural inclination may be to use genetically
related primates, like chimpanzees! But, chimps are endangered… Baboons on the other hand,
are genetically similar to chimps and humans, and are relatively plentiful! But, they're
terrible transplant donors! Their organs are too small and matching our blood types is
incredibly rare. In fact, throughout history doctors have been pretty slapdash at picking
animals, trying sheep, rabbits, dogs, cats, rats, chickens… even pigeons!! It turns
out pigs might be one of the best. Despite having little genetic commonality, pigs bodies
and organs are almost identical in form and function to a human’s! The heart, specifically,
is roughly the same size and shape. Because of this, we already use pig valves in some
heart repair! Additionally, pigs are plentiful, and society has no real qualms about killing
them -- even if some people do.
Okay, so we've got our pig, now what? Well, any time a foreign object enters your body,
your immune system mounts a defense to wipe out the intruder If someone just jams a new
heart in you, your body will assume that it is a giant virus or some other invader and
begin attacking it with a fervor. There are two ways to stop this, one: immunosuppressant
drugs -- literally shut down the immune system; obviously not ideal… OR you can trick the
immune system into thinking the new organ was part of the body the whole time. Simply
put, most tissues have proteins on their surface called Human Leukocyte Antigens. They're like
license plates, telling your immune system which tissues are local. If researchers can
take the plates off the new organ (or match them) the immune system will leave it be.
In this case, doctors implanted the pig heart into the baboon's abdomen and used drugs to
suppressed the immune system. But, there's another concern! Pigs, unlike humans, have
ANOTHER antigen called galactose oligosaccharide -- or just Gal. In the 90s, researchers realized
because humans don't make Gal our immune systems goes crazy when it sees it. It's like seeing
a license plate from Nazi Germany in Cleveland. The organ can be rejected in MINUTES. In 2007,
cloning technology finally resulted in a gal knockout pig! Basically, a pig without the
gene to make the gal antigen. This pig heart, was one of those genetically modified gal
knockouts. No antigen backlash! 945 days of hearty fun!
It might have gone longer, but the heart began to degrade as the immunosuppressants were
relieved. This is a really exciting test, because if the pig heart can survive and pump
blood in a close human relative even for a short time; it might open the doors for pig
parts to become 'bridge organs' for those waiting for a human ones. 22 patients die
everyday waiting for donor organs! Broadening the field of potential donors could save thousands
of people.
Obviously, the ability to keep the body from rejecting any foreign organ is amazing…
But to use one from another species is just insanely medievally cool. Plenty more research
still needs to be done, but still, can you imagine walking around with a pig heart?!
Wow. I wonder if I'd become more delicious. MMMMmmm.
Look if you're into weird transplants, then you should definitely check out Julian's video
about how doctors are transplanting penises. Julian totally went there. OR, if you want
to know more about how we swap out antigen license plates to help organs work in new
people,: Amy's got that for you, right here.
Let's say you needed an organ… would you take a pig heart? Do you have qualms? Tell
me about it.