Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

U.S. surgeons transplant pig heart into human patient

apnews.com

Post reply on HN
Print view View original

81–90 of 731 posts

Re: U.S. surgeons transplant pig heart into human patient

#81

Post by pazimzadeh »

Finnucane wrote: post #73
ardit33 wrote: post #71

Earlier quoted context omitted.

I heard they are humanized 'pigs'. Ie. engineered so their organs don't trigger our immune system. Not sure how true is this, or it is just a myth.

The article states they changed a sugar that triggered rejection.

Exactly:

"More than 95% of human anti-pig antibodies are directed against 3 pig carbohydrates: Gal 1 to 3αGal (≈80%–90%), Neu5Gc (≈5%–15%), and β4Gal (1%–5%)"

"To reduce anti-pig antibody binding to the xenograft, the 3 principal carbohydrate antigen targets have each been successfully removed from pigs by gene knockout (KO) (Figure 3)"

Progress Toward Cardiac Xenotransplantation https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7990044/

Re: U.S. surgeons transplant pig heart into human patient

#82

Post by p_j_w »

trwhite wrote: post #72

A sad sign of what things have come to when a man's last hope at survival is a pig heart.

Maybe I'm missing something, but what's so sad about this situation versus the past? In the past, he would have just died, but "what things have come to" is that medical technology has advanced to the point where he has a shot of making it another few years.

Re: U.S. surgeons transplant pig heart into human patient

#83

Post by OminousWeapons »

livinglist wrote: post #58
Ensorceled wrote: post #47

Reminder: We've been replacing human heart VALVES with pig valves for a long time now. My grandmother lived for almost a decade after her replacement. https://www.heart-valve-surgery.com/learning/pig-valve-repla...

May I ask how much did it cost and did insurance cover it?

A surgical aortic valve replacement (SAVR) for example will cost ~50K I believe? It will be covered by insurance if it is necessary.

There are also less invasive forms of valve replacement (transcatheter / percutaneous) which involve collapsing a synthetic valve around a balloon at the end of a catheter, inserting the assembly into a femoral artery, guiding the valve into the heart and into the open damaged valve, and then inflating the balloon and deploying the new valve inside of the damaged old valve. In SAVR the old valve is removed and the new one is sewn in. In transcatheter aortic valve replacement (TAVR), the old valve is held open by the new valve.

Re: U.S. surgeons transplant pig heart into human patient

#84

Post by Supermancho »

garren wrote: post #15

I wonder why a pig heart rather than one from another primate? The article mentions a baboon heart in an earlier attempt at xenotransplantation with an infant. Is a pig’s heart as, or more, compatible or is it more a matter of availability?

At age 2, I was a candidate for a monkey heart transplant, as I had a perforated aortic valve and surgery on tissue with the consistency of wet-toilet paper in an infant had a very high mortality rate (the girl on the table before I went in had died). My parents declined the monkey transplant. Good thing. The intended recipients of multiple attempts at the monkey hearts, died. I eventually received a primitive mechanical implant, which I quickly outgrew. By the 80s I had another surgery to replace it (https://en.wikipedia.org/wiki/Bj%C3%B6rk%E2%80%93Shiley_valv...). This had it's own dangers, as the strut would fail along 2 ends of a sizing graph (most people were at the larger size end). I sat safely on the bell curve. I kept that into my 30s which caused various problems with the aortic stem and thickening of the left ventricle.

Now I'm rocking the On-X, which is superior in innumerable ways.

Re: U.S. surgeons transplant pig heart into human patient

#85

Post by pazimzadeh »

dnautics wrote: post #57
robbiep wrote: post #51

Earlier quoted context omitted.

They’re not making the pig more human, they’re removing the markers of ‘foreign’ that would make it an immune target. So it’s a nice vanilla organ that minimally attracts the attention of the immune system.

On the other hand (and I am being flippant... Slightly) how do you know that removing this one gene doesn't unlock consciousness?

A strange idea but theoretically possible. Although it wasn't one of the genes targeted in this study, humans are the only animals which have the Neu4Ac form of the sialic acid sugar, instead of Neu5Ac, and the brain is one of the regions that is most heavily sialiated in humans and could be one of the things that sets us apart.

https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7153325/

Re: U.S. surgeons transplant pig heart into human patient

#86

Post by majormajor »

woke_neoliberal wrote: post #35

The pig was modified to remove presentation of immunogenic sugars on the cell surface. Unfortunately, the recipient needs to be on immunosuppressants the rest of their life. This rekindles discussions back in school about chimeras... in order for the organs to be immunocompatible, the donor needs to be partially human. What % is too human to harvest for organs? I suppose it's still too soon to answer such questions,…

What part do you think opens that door?

Human organ recipients also need immunosuppressants forever, outside of rare cases. This particular case sounds like a very small modification to the source pig, not a pig carrying a human organ.

Re: U.S. surgeons transplant pig heart into human patient

#87

Post by TulliusCicero »

Ensorceled wrote: post #47

Reminder: We've been replacing human heart VALVES with pig valves for a long time now. My grandmother lived for almost a decade after her replacement. https://www.heart-valve-surgery.com/learning/pig-valve-repla...

According to another article, that was also true of this patient.

Re: U.S. surgeons transplant pig heart into human patient

#88

Post by TulliusCicero »

robbiep wrote: post #51
woke_neoliberal wrote: post #35

The pig was modified to remove presentation of immunogenic sugars on the cell surface. Unfortunately, the recipient needs to be on immunosuppressants the rest of their life. This rekindles discussions back in school about chimeras... in order for the organs to be immunocompatible, the donor needs to be partially human. What % is too human to harvest for organs? I suppose it's still too soon to answer such questions,…

They’re not making the pig more human, they’re removing the markers of ‘foreign’ that would make it an immune target. So it’s a nice vanilla organ that minimally attracts the attention of the immune system.

According to another article: https://www.usatoday.com/story/news/health/2022/01/10/human-...

> Three genes were turned off that might otherwise have triggered an immediate immune rejection – the recognition of a pig organ as coming from a different species. Six human genes were added to prevent blood from coagulating in the heart, improve molecular compatibility and reduce the risk of rejection.

> One final gene was turned off to keep the pig from growing too large.

So they actually did make the pig a tiny bit human.

Re: U.S. surgeons transplant pig heart into human patient

#89

Post by meepmorp »

Victerius wrote: post #48
tricky wrote: post #26

You might be asking, why a pig? I don't know, but forever ago I wrote software for a cardiovascular imaging lab and pigs were their primary test subjects. I was like, "why pigs?" and the PI was like, "Imaging-wise, pig hearts aren't too different from humans. Plus, we can give them a heart attack in the scanner and not go to jail. Some labs use dogs. I just can't do that."

What ... happens to the pigs who get accidental heart attacks? Are they ...? Do they ...?

They get rushed to a special hospital for pigs and then go to live long happy lives with other porcine MI survivors on a farm far, far away.

Re: U.S. surgeons transplant pig heart into human patient

#90

Post by TulliusCicero »

monkeybutton wrote: post #54
hwbehrens wrote: post #38

If pigs (or any animal) broaden the compatibility to other organs, what are the ethical implications for raising them with the intention to harvest their organs, if any? On one hand, we already raise pigs to kill and eat routinely, and (mostly) people don't care - is this any different than say, buying a pig heart at the market to eat? On the other hand, it does somehow feel different to me, perhaps because sharing o…

What about growing human organs in pigs? Like the pigoons from Oryx and Crake. http://www.technovelgy.com/ct/content.asp?Bnum=1177

Then you have the reverse problem of the pigs rejecting the human organs, I suppose.
Post reply on HN