
A new approach to generating human organs is to grow them inside pigs or sheep - rl3
http://www.technologyreview.com/news/545106/human-animal-chimeras-are-gestating-on-us-research-farms/
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rfreytag
One problem with human-animal tissue contact is the enhanced opportunity for
zoonosis (cross-species diseases).

In the early 1990's there was a proposal to enclose pig Islets of Langerhans
(insulin and glucagon producing) tissue in capsules with sub-cellular pores
and implant them in diabetics. The idea was that rejection was less likely
without direct cellular contact and the diabetics would gain something
resembling natural blood-sugar regulation.

There were two problems that persist over the three decades of subsequent
research: 1. rejection does still prove to be a problem, and 2. the problem
was that pig viruses emitted by the transplanted capsules might eventually
find an "error" that would infect the human host resulting in a brand new
zoonosis shared by pigs and humans. The FDA refused trials as a result (see
the last paragraph of this section in wikipedia:
[https://en.wikipedia.org/wiki/Pancreatic_islets#Transplantat...](https://en.wikipedia.org/wiki/Pancreatic_islets#Transplantation)
\- that article leaves out is the distinct possibility of other porcine
viruses that might cross-species given the persistent opportunity this therapy
might provide).

If one is being conservative - always a good idea when the prospect of new
diseases are in the offing - the process of putting human tissues in pigs and
then back in humans is at least as risky as merely putting live pig tissue
directly into humans.

~~~
logfromblammo
That might be addressed by modifying the animal to produce the dsired organ at
the correct size, scrubbing out all livestock cells with strong detergents,
then seeding the organ extracellular matrix with progenitor cells from the
intended recipient.

There would be no livestock cells left, so no worry about zoonotic pathogens.

~~~
stcredzero
If you're leaving behind a protein scaffolding, wouldn't you still have to
worry about prion diseases? What about viruses?

~~~
logfromblammo
The only known mammalian prion is PrP, which noticeably affects animal
behavior, and is detectable by testing lymph. If the animal has prion-related
encephalopathy, you burn it.

Viruses cannot reproduce without living cells. Viruses that employ lipid
capsids would likely be removed by the detergent along with the cells. Some
viruses do embed in a type of extracellular matrix (HTLV-1). As far as I am
aware, no research has been done on the transmissibility of viruses in
decellularized animal organs from donor to recipient.

I presume that those facing imminent organ failure would rather catch a cold
from a pig and recover in quarantine observation than die while waiting for
such research to conclude.

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Procrastes
That's the origin story for the pigoons in Oryx and Crake.
[https://en.wikipedia.org/wiki/Oryx_and_Crake](https://en.wikipedia.org/wiki/Oryx_and_Crake)

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rasur
Not trying to troll, but I can see the idea of organs grown in pigs not going
down particularly well with the members of at least 2 world religions.

~~~
justin66
Being given the option of dying or not dying is the sort of thing that causes
people to rethink dogma.

~~~
rasur
Hmm, I'd _like_ to agree with you, but there are plenty of examples where this
kind of situation has occurred and the dogma won :(

EDIT: To clarify; I mean dying vs not dying, rather than specifically having
an animal-grown organ inserted.

~~~
CaptSpify
Personally, I think people _should_ have a choice. But I'm guessing we'll see
both: Some will rethink their dogma, and others will put their money where
their mouth is.

~~~
rasur
I couldn't agree more that people _should_ have a choice.

Whether they exercise that freedom of choice though...

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bayesianhorse
It's not exactly a new approach, but it may finally get off the ground...

~~~
gozur88
My first thought when I read the title was "I'm pretty sure this idea made a
big splash about twenty years ago."

~~~
zardo
Retroviruses were the major showstopper, now they can identify them and remove
them from the genome. Maybe they run into another roadblock, but... Maybe it
works this time.

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JoeAltmaier
A small step to growing intelligent pigs? Put a human brain in one?

~~~
ohyes
Pigs are already intelligent.

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cowpig
Pigoons!

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theworstshill
Duke Nukem - how Pig Cops came to be.

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cargo54
Like we didn't have enough sheep and pig headed people around...

~~~
ant6n
You won't grow heads in pigs and sheeps. More like livers and hearts. So
they'll be pig-livered and sheep-hearted.

~~~
justaman
If given the choice, please grow my organs inside of a sheep.

~~~
k__
Would be kinda funny if they only get it reliably working in pigs.

