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  • What you're seeing right now is a pig heart  beating inside a human being for  

  • the first time ever. This experimental organ  transplant is breaking so many boundaries,  

  • but let’s start with the fact that  it involves gene editing andcocaine

  • Let’s start simple. Any transfer of  cells or tissues across species is called  

  • xenotransplantation. Even though it sounds like  science fiction, this is actually nothing new. Pig  

  • heart valves have been replacing worn-out  human heart valves for the past 30 years.  

  • That’s because pig hearts are actually very  similar in structure and size to human hearts

  • But replacing the entire heart with  one from another species

  • that’s totally uncharted territory.

  • See, a major roadblock to xenotransplantation  

  • is our immune systems. Pig cells are covered in  surface structures that our body recognizes as  

  • non-human. This can trigger something called graft  rejection, where the human recipient’s immune  

  • system tries to get rid of the new organ. This  even happens with transplants from other humans

  • But we need whole hearts, and we need them  now. Heart disease is the leading cause of  

  • death worldwide. Even in places that have enough  resources to provide valve replacements or heart  

  • transplants, there just aren’t enough organs to go around.

  • Thousands of people in the U.S. alone are on  

  • the waitlist for a new heart, and an average of 17  people on organ transplant waitlists die everyday

  • That’s because, until now, weve  only had human hearts as our whole  

  • organ transplant option. Pig hearts fit the  bill and could help us solve this problem,  

  • but what about that pesky immune responseThe answer just might begenetic modification

  • The parent company behind Dolly the sheep

  • you know, the world’s first cloned animal,

  • has also been working on rearing pigs  genetically engineered just for organ  

  • transplant. In 2021, these pigs were used  to successfully transplant kidneys into two  

  • legally brain dead people whose bodies were being kept  alive on ventilators. So, we moved on to hearts

  • Scientists used gene-editing technology to make  ten major genetic modifications to these pigs:

  • knocking outthree pig genes behind those cell  surface molecules that trigger the human immune  

  • response, removing a tissue proliferation genemaking sure the pig heart won’t keep growing  

  • after it’s inside the recipient, and inserting  six human genes that will hopefully help with  

  • immune acceptance of the heart. There are also several other  

  • never-before-used techniques at play  here. The doctors are giving the recipient  

  • an experimental drug to suppress his immune system  for extra protection against graft rejection. They  

  • also used a brand new machine to pump fluid through  the heart while it was awaiting transplant

  • And that fluid contained relatively  standard cortisol and adrenaline,  

  • with the nonstandard addition of cocaine. It’s  not clear exactly how or why, but cocaine seems to  

  • help keep the heart ready for transplant between pig and human.

  • Getting approval to use the drug apparently caused a bit

  • of a nightmare, but the team does think it helped. Now, with xenotransplantation, there is also a risk  

  • of transferring diseases across speciesThere are lots of viruses lurking in pig  

  • genomes. The transplant scientists made  ‘precision alterationsto remove these in the  

  • hopes of making disease transfer less likelyBut this is a ‘time will tellkind of deal

  • Sowho would say yes to all this? 57-year  old David Bennett was the recipient of  

  • this pig heart. And Bennett’s terminal heart  disease eventually made him too sick for  

  • any other optionit was this experimental pig heart surgery or death.

  • The FDA gave emergency approval for just this one  

  • procedure, making Bennett the only patient allowed  to have this surgery. The scientists will keep  

  • testing the procedure in baboons, but they really  want to get to clinical trials with even more humans

  • And of course, this breakthrough raises all kinds  of ethical questions. ‘Farminghearts like this  

  • means a reliable supply of these organs could  be available as soon as patients need them,  

  • butraising intelligent animals like pigs  just to be slaughtered for organ donation  

  • has many animal rights activists in uproar. There’s also the medical ethics of it all.  

  • Is it even ethical to offer a dangerous  procedure with so many unknowns to people who  

  • are terminally ill and maybe desperateessentially making them human guinea pigs

  • As of this writing in February, 2022, Bennett  appears to be doing well, with no signs of  

  • rejection yet and he's able to breathe and speak on  his own.

  • It is too early to say if the surgery  

  • will be a long-term success, but it is an exciting first  step towards a solution to the world’s organ  

  • shortage. Who knows? Maybe in the future, we could  see genetically modified xenotransplantation of organs

  • become a norm for other organs too. Want more on how to fix a broken heart?  

  • Then check out this video on live heart patches  here, and keep coming back to Seeker for all  

  • your groundbreaking biomedical news. If you have  another topic like this you want us to cover,  

  • leave us a comment down below, and as alwaysthanks for watching. I’ll see you next time.

What you're seeing right now is a pig heart  beating inside a human being for  

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Inside the First Ever Pig to Human Heart Transplant

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    Summer に公開 2022 年 02 月 04 日
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