Slashdot Mirror
Pigs with Human Genes
LGRiske writes "In a step toward creating herds of pigs that could provide organs for transplanting into humans, Italian researchers manipulated swine sperm to make an animal strain that carries human genes in the heart, liver and kidneys."
Does this mean that a doctor can extract stem cells from me, clone a genetically designed pig with a suitable spare part for my body and then make a transplant without any complications and added toxins to prevent my body from rejecting the organ. In that case it sounds great
How do they address the issue that most cloned animals turn out sick, I don't want a sick organ in replacement for my allready sick organ!
I believe its acceptable to harvest pigs for organs, since we already harvest them for food. Since we're willing to butcher them and eat them, there shouldn't be any ethical objection to butchering them for parts.
On the other hand, we don't eat humans. And somehow, I don't think it would be economically viable to start breeding humans with pig organs, so we could eat them. Thus, you've run into a mental block that people will associate with the progress of growing humans for parts.
Now if you suggested breeding pigs with human organs simply for consumption, you'd probably be forbidden by law, on the grounds that its too much like cannibalism.
Basically, if most people would consider eating it, its acceptable to farm and butcher it for whatever purpose you like, especially if it helps humans. On the other hand, if you don't normally eat the thing, I wouldn't suggest trying to use it as a host for organs.
Wouldnt it be "easier" to just have a replacement human with say, no brain (so its not "really" a clone) living assisted by machines waiting for its parts to be harvested?
That's pretty much what this is, but instead of using expensive, complicated machines to keep the organs alive we use cheap, simple pigs.
I am a Karma Library.
All cells in the body carry on their outer membranes molecules that identify them as being part of the body. now finding all these genes, cloning them all into pig cells AND removing all native pig recognition molecules would be the way to go, WERE IT NOT that the pig itself would not be viable 'cause its own cells are not recognized anymore. any slight amount of alien molecules left causes a massive attack of the host immunologic system (white blood cells etc). it is possible to overcome this _PARTIALLY_ by weakening the immunosystem with chemicals.
I reseached the possibilities of pig organ usage for transplantation.. believe me, it might be possible some day, but that day is WAY ahead of us.
the alternative of growing new organs from stem cells (ie programming from the ground up) is up to now a much more promising than modifying pigs (ie patch core components of a massive _unknown_ project while porting it to another OS)
my 2 eurocents
"Essentially, what these guys did was find a way to add a gene into a pig by messing with the sperm. This technique can't be used for removing genes, and can't replace genes. They can only add genes."
Even if you can't replace genes with this method, you may be able to do the functional equivalent. For instance, add the new gene, and then add a gene which counteracts the original (antisense, targeted ribozyme, RNA silencing, etc.). So it's entirely possible that you could knock out or replace the marker proteins and sugar-producing pathways. There are an awful lot of them, of course -- but no one ever claimed this would be easy.
"Cell morphology/DNA. Pig DNA is not human DNA. Pig cells are not human cells. Pig cells expressing "human genes" are closer, but when these cells replicate, when you get a virus, when something goes wrong.. what's gonna fix it? "
An obvious observation, of course pig!=human. As for the rest of this, you're a little fuzzy on just what exactly your concerns are. Now, "when these cells replicate", I imagine they should in the course of normal tissue repair and turnover. Are you referring to the possibility that cells will migrate out of the transplant (resulting in microchimerism)? Such a thing could cause some rejection problems, but that's really a minor case compared to the big rejection problem of the whole organ. I would be more concerned about the possibility of porcine immune cells hitching a ride with the organ -- that's a real concern (Note: There shouldn't be enough to cause any sort of GVHD, it's more of problem with increasing rejection risks). There are ways to deplete immune cells, though, I think some of them have been tried (in human organ transplants).
As for the virus, I will assume you mean the problems of introducing possible porcine viruses. For most viruses, you can raise the animals in isolation, and then screen them before/during/after. However, there is one exception -- Porcine Endogenous Retrovirus (PERV -- yes, that's the acronym). I believe it's present in the genome of just about all pigs. It's been a topic of a great deal of research, and for a time it caused an FDA ban of all xenografting trials (since lifted). Although PERV doesn't seem to be able to spread in humans, I imagine that if we could knock out a dozen other genes from the pig genome, we could probably knock out the viral sequence too.
"How do we know what will happen?"
How about finding out by the empirical method?
"So tell me, how is this really news? The headline should have read "Scientists develop new but limited method for gene implantation." It's been done."
I'll agree with you here, it's another case of an attention-grabbing sensational headline.
-Guppy
Pig. Even if you managed to have a pig brain in an otherwise human body somehow, the result would still not be human. We don't know exactly what makes us human, but we do know that most of whatever it is resides in the brain.
Pigs, like many species, have a large number of resident viruses, particularly retroviruses. They and the pigs are well-adapted for each other, and the pigs show little to no ill effect. Some of them are likely so benign to the pigs that we have no idea that they're there. (Indeed, many of these are revealed only by genetic analysis.)
But then what do we want to do? Stick a pig organ in Grandma to save her life, or at least prolong it for a while? So, we've got a person who was unhealthy to begin with, we introduce dozens of foreign viruses directly into the body, and, to top it all off, we completely suppress the immune system so that the organ isn't rejected. I'm not sure that I can even imagine a a scenario more favorable for a virus to make the species jump. And if one did, you can bet that we wouldn't have much natural resistance to it...
1) Nobody knows what might happen if these pigs somehow were released into the wild. A new species of 'super-pig' could potentionally cause wisespread damage if they escaped captivity
No.
2) Pigs are dirty, they typically roll in their own feces. This is not an appropriate animal to use for 'human' organs.
No. Having a dirty skin does not have any impact of the quality of the organ.
3) Using Pigs in such a fasion is inhumane. Nobody knows the pain these pigs could live with because we have set off certain gene sequences we should not have
Pigs that are used for food are treated very poorly, and go through great pains. If this really is a concern of yours, start by balking at that problem, which affects many orders of magnitude more pigs.
4) Pigs are not kosher, and Jewish or Moslems would not be able to benefit from these advances. That's alienting 1/5 of the planet right there from being able to benefit from this.
Is this a representative attitude of yours? If something cannot benefit everyone, then it should not be done? If such logic had been widely practiced we would still live in caves.
5) We are tampering with God's work. Pigs were created perfect the way they are, as are we. Toying with genes is tampering with God's perfect work and SHOULD not be done under any sane principals.
Pigs, the way they are, were created by man, through millenia of genetic manipulation (specifically, selective breeding). Sorry, the harm has already been done.
Tor