Halfbakery: Early foetal human / animal organ transplant inoculations

If you introduce foreign stem cells into a foetus before the immune system has developed when it does kick in & calibrate itself it will recognise the foreign cells as native to the organism & won’t reject them.

We know it works because if it didn’t the Cambridge Geep (created by mashing two equally developed early embryos from a goat & sheep together while they were still just little balls of unformed cells) could never have existed.

This happens constantly in nature – an awful lot of us who had siblings in the womb will have small colonies of cells that migrated to us in the womb.

Sometimes only one of a multiple pregnancy makes it to term so it can also happen with single births.

They don’t even have to be the same sex.

One well-known actress has a small percentage of cells carrying XY chromosomes floating around her body.

And no she’s not a hermaphrodite – you need a lot more than a few migratory floaters for that, probably a 50/50 split – which requires two equally developed embryos to merge in the womb during early development.

If you introduce a few stray stem cells from a younger foetus into an older embryo that’s further along developmentally they essentially go native taking their cues from the cells around them & the organism they find themselves in.

When it’s done that way the foreign cells have zero input in the development of the foetus.

You wont end up with a chimerical creature like you do when an equal quantity of cells at the same stage of development are mashed together (like the Geep was).

Monkeys injected with human stem cells this way look exactly like monkeys, act exactly like monkeys & are just monkeys.

Pigs injected with human stem cells in an attempt to cut down on tissue rejection in trans species transplants of their organs (a completely fruitless avenue of research) are also just pigs & have never displayed any non-pig qualities.

So humans injected with pig stem cells at a comparatively late stage of development can be expected to be in no way affected by it.

What it would mean is that their immune system when it does kick in & calibrate will then forever after recognise those pig cells as belonging & won’t attack them if any organs from that individual animal (or one of the same tissue type) is transplanted later in life.

No tissue rejection – limitless supplies of organ, blood & skin for emergency grafts.

If you carefully choose an animal without any lethal recessives (so it can breed with itself) – use chromosomal engineering to insure all it’s chromosomes are mirrored pairs with both sides the same – clone it, take a cell samples & swap out the y chromosome for a copy of the x chromosome (assuming it’s male of course, otherwise swap in a y chromosome) & re-clone it using those cells.

You then have a male & female that you can breed from normally & all the offspring whether male or female will essentially be clones of the one animal.

So you can then just breed herds of organ replacement pigs without all the expensive lab techniques.

I suggest pigs because the organs are generally about the right size for humans plus their skin is similar to peoples so it could be used for emergency skin grafts (a definite advantage over goats or sheep) – I say emergency grafts because it won’t match perfectly (not for everyone) but it will certainly do until enough of a bodies own skin cells can be cultured to provide a more cosmetically appealing result.

Some people might worry about people giving birth to piglets or human pig hybrids if the guest cells end up in the testis or ovaries but this really shouldn't be a problem.

1. The guest cells tend to stay where they are put – so inject them in the sole of the foot.

2. Pig sperm can’t penetrate a human egg cell (& vice versa) – if it could then what with all the farmyard perverts that have existed through the centuries it would already have happened.

3. Even if the sperm could penetrate the egg human & pig DNA should be incompatible & unable to mesh - we also have a different number of chromosomes (ok so chromosomal mismatch isn't always a complete bar to reproduction, it's not making it any easyer though is it).

4. If the chromosomes & DNA found a way to hook up the incompatibilities should create enough lethal combinations to prevent any embryo coming to term – enough embryos with two human genetic parents have development issues that prevent them coming to term, so really, what chance do you really think a half human hybrid has.

5. And even if they were genetically & chromosomally viable a human womb is a hostile environment for a pig foetus – temperature & ph levels are all wrong & it can be a pretty hostile place for fully human embryos (case in point, I’m rhesus negative & mum is rhesus positive, she miscarried a previous rhesus negative before me so her immune system was loaded with antibodies that tried to kill me in the womb & I came out severely jaundiced) so once again what chance do you really think a half human foetus would have in a human womb.

6. Besides all that the cells might not need to survive in the body for long past the immune systems calibration so they could be chemically coshed to prevent cell division before injection (individual cells should last long enough) – or else killed off after the baby was a few months old using the targeted drug delivery methods being developed for gene therapy & cancer treatments.

Some research has been put into making animal organs more compatible for human transplant.

Injecting human stem cells into the animal foetus so it has a small percentage of compatible cells for one - but these cells still need to be tissue typed for the recipient – so even if that worked you’d have to maintain several herds (one for each tissue type) – & it doesn’t work anyway.

With that method the vast majority of the cells are still pig cells, so still rejected, will be killed by the immune system & then rot inside you resulting in gangrene & blood poisoning, which would kill you if it wasn’t for the fact that not enough of the organs cells remain for it to function so you die from the resulting organ failure first.

Added here to avoid dragging this back to the top & annoying anyone who thought they were done with it ;)

As I said the 'guest' cells stay where you put them & a subsequent Google search suggest the technique is to inject enough cells in specific organs so human cells will be in the majority in them.

So it does work but the patient has to wait for their organ (the animal) to grow, not much use for a fast illnesses or violent accident.

Unless you take immune system suppressants – & then the first time you catch a common cold it develops into full- blown hypothermia & you die.

Another approach might be injecting pig nucleic DNA into a human egg cell & then cloning it.

This would produce a perfectly normal pig in all respects.

As the mitochondria doesn’t have any expression in the organism proper, it merely governs cell chemistry

So I suppose some things like the inability (or not) to properly metabolise certain foodstuffs might be seated there (like lactose intolerance?).

Which could explain why some transplant patients claim cravings for foods they didn’t like before but their donor did.

They’ve just had a chunk of their body replaced with cells that may have slightly different chemical / nutritional requirements from their own & the bodies hormonal system prompted by those cells is just telling them what the cells need?

Anyway I’m going off topic – switching a pigs mitochondria & (presumably) its cell wall shape & structure this way might be hoped to cut down on tissue rejection.

But - going back to my mums immune system (the one that tried to kill me in the womb) it’s clear that, as we share the same mitochondria, tissue type isn’t determined by that (at least not alone).

So that doesn’t work either - I’ve never heard of anyone doing any research on it anyway.

So none of the approaches for adapting the animal organs to be less prone to tissue rejection I’ve come across (or am able to think of) appear to work.

While inoculating the foetus in the womb against rejection of the animal tissue will (or so it seems).

And yet I can’t find a smidgen of a hint anywhere that anyone else has considered this.

Oh I know the usual suspects (religious nutters & the ‘moral majority’) would all throw a fit.

But really:

How’s it any worse than rubbing pus from a cowpox pustule into a small cut in a child’s arm to protect them from smallpox (the original vaccination).

Its not like vaccinations have really changed any since then, most are still essentially a small dose of chemically stunned or weakened virus.

Under the guidance of the state parents routinely inject alien DNA into their children & no one ever bats an eyelid so why not this.

And just think of the benefits – of course it’s not much good for those of us that are already here (accept that it will protect a lot of our existing medical resources from expanding pressures from new births).

Thoughts? ;)