Ethics of using Stem Cells to Create Human Chimeras

[Sir Salty]

Hey all I am a student studying A'levels and this is my first post.

 

Recently I have been reading up about the usage of stem cells in research and some of the ethical issues that come with it. In this thread I specifically want to discuss whether using stem cells to create human chimeras is an ethical practice. This involves taking stem cells (models have successfully used IPSCs) to create a chimera; a hybrid of a creature. The purpose of this would be to grow human organs within another creature which could then be harvested and transplanted into a human potentially solving the current organ supply crisis. Of course there are still many limitations before it becomes a reality, however the research is taking place and more can be read about it in detail in a science article BBC recently posted: http://www.bbc.com/news/health-38717930.

 

I am very curious as to what people think about this research and the ethics behind it, mainly focusing on:

1) Is it ethical to use embryotic pluripotent stem cells (although in this case there has been some success with IPSCs).

2) Is it ethical to create human chimeras, or perhaps better to ask, to what extent should we allow these organisms to develop before understand what they really are.

 

I am currently quite open-minded about this and would like strong arguements from both sides to be presented. For the sake of arguement and getting a deeper understanding I will try my best to actively argue and throw out points to consider from both sides of the arguement. Please keep in mind that it is my first thread and I am only an A'level student so forgive my ignorance in some areas especially if I need additional explanation.

Cheers, Sir Salty.

[fiveworlds]

What a great topic. We have been modifying animals for years to produce insulin for diabetics etc. I would think that so long as the animals is not in considerable pain throughout life and the mutation isn't spread to the rest of the animal population then it is fairly okay.

[imatfaal]

Whilst sometimes it is necessary to ask complex multifaceted questions it can be highly instructive to try and break these down to "component parts" to find out if there exists a nucleus of ethical objection on a far more basic level.

 

It would seem to me that your question has three important parts

1. Is it ethical to use embryonic cells?

2. Is it ethical to create animal human hybrids / chimeras? *

3. Is it ethical to utilise animals to provide medical cures for humans?

 

These are answerable separately and if (big if) one can answer them then and only then can you move forward to a synthesis and provide an argument that the specific combination of your original question is also answerable.

 

*I also think this is a highly emotive usage and think fiveworlds made a good point about limitation both within the animal and the species

[Bender]

We breed animals for the sole purpose of eating them. Why shouldn't we breed them to save our lives?

 

The only animals that can contain human-sized organs are larger mammals, who typically don't breed very fast. There is very little danger of them escaping and spreading the mutations in the wild.

[Sir Salty]

To clarify I do understand that there are many ethical questions that can be asked of this procedure and therefore would like to mainly focus on 1) the use of embryonic stem cells, and 2) is it ethical to create human chimeras. In the 2nd point I'm more interested in how we should go about creating and allowing such a creature to develop as it would not only be against many religous beliefs, but also if we should consider it different from any other animal which is non-human. However feel free to discuss everything relating to the topic as it is all fascinating.

 

I would like to add in response to those mentioning the potential danger of them escaping and spreading mutations that it is highly unlikely that they could even reproduce similarly to how mules cannot reproduce (please correct me on this if I am wrong). However the reason I assume this is because the human stem cells would be transplanted into the embryo of the creature and so human DNA would be part of the animal as it grows up.

Also they would very likely have to be carefully contained in laboratory like conditions anyways in order to make sure they are protected from all disease or infection. Of course this would fall under regulations which are considered humane for the animals. This would reduce the risk of the escaping to near nought especially considering that they would be harvested around the time or slightly before the become mature enough to reproduce because it is at that same time the animal is the right size and the organ is fully developed. However this is all theoretical and would greatly depend on the animal being used.

Edited March 23, 2017 by Sir Salty

[Bender]

Religious beliefs don't have to be considered. As long as no one is forcing religious people to undergo such treatment or to participate in the process, they have no say in the matter (except if they happen to be an expert in a relevant field and can keep their religious beliefs out of it).

 

With that out of the way

1) I see no reason not to use human embryonic stem cells. It's not like they are anything close to being a person: it's just a tissue sample.

2) We already share a large percentage of our DNA with other mammals. Why would we care about changing that percentage slightly?

[Velocity_Boy]

What a great topic. We have been modifying animals for years to produce insulin for diabetics etc. I would think that so long as the animals is not in considerable pain throughout life and the mutation isn't spread to the rest of the animal population then it is fairly okay.

 

Uhh, I'm fairly certain the OP is referring to the usage of human embryonic stem cells. Not those of animals.

[fiveworlds]

Uhh, I'm fairly certain the OP is referring to the usage of human embryonic stem cells. Not those of animals.

 

 

He was on about genetically modifying animals to grow organs. For instance making a sheep grow a human lung then killing the sheep and transplanting the lung into somebody in need of an organ donation. I wonder if it will be possible to grow blood for transplantation in the future instead of relying on donations all the time. It is a really interesting topic which has the potential to save a lot of human lives. The stem cells would most likely be grown in a sterile laboratory.

 

The purpose of this would be to grow human organs within another creature which could then be harvested and transplanted into a human potentially solving the current organ supply crisis.

 

Edited March 25, 2017 by fiveworlds

[Sir Salty]

2) We already share a large percentage of our DNA with other mammals. Why would we care about changing that percentage slightly?

Because by changing that percentage by even 1% is already the difference between 2 completely different organisms. Therefore who knows what the resultant organism would be like. Perhaps in the future we would be able to control precisely what the animal would be like, which would be the aim of the research of course so that scientists can develop perhaps a sheep with a human pancreas to harvest. However to get to that point first a "creature" containing both human DNA and in this case sheep DNA would have to be allowed to develop experimentally without knowing exactly what the outcome is. Futhermore theoretically, say that we do get to the stage where we can grow a sheep that has a human pancreas. Why not for increase in efficiency also have that same sheep grow human lungs and heart. However is the organism still a sheep or has it become more human? Therefore we will eventually get to a point where we are growing creatures which resemble humans more than anything else and killing them.

[Bender]

I'm no expert on organ donation, but I don't think you need all the organs to be 100% human. That would be impossible anyway, since the cells of the organs would contain all the DNA of the sheep.

 

What we need is changing the chemistry of the organs in such a way that is not rejected by and can function in a human body. Still different from a human organ.

[Sir Salty]

I'm no expert on organ donation, but I don't think you need all the organs to be 100% human. That would be impossible anyway, since the cells of the organs would contain all the DNA of the sheep.

 

What we need is changing the chemistry of the organs in such a way that is not rejected by and can function in a human body. Still different from a human organ.

 

What you are saying is correct, theoretically, as long as the antigens present on the surface are removed and the structure is similar enough then it should be accepted, atleast with immunosuppressants. Therefore another method being studied is xenotransplantation, the transplantation of an animal organ (genetically modified perhaps but still considered that animal). However I am discussing a similar, although different process which has different applications. I would be a lot less hesitant to say that xenotransplantation is ethical, however with chimeras you are creating a hybrid creature, part human part another animal, possibly multiple animals. So perhaps the creature is only partially human, however at which point is it too human to be considered unethical (remeber we are growing this creature specifically to be killed), of course very subjective, which is why I want to hear others' opinions. And some would argue that mixing any human DNA with another animal is completely unethical.

 

Also I would like to say that according to my knowledge, correct me if I'm wrong, the organ itself will be purely human, atleast the important parts including the surface antigens will be. This is because the blastocyst of the host animal is genetically modified so it cannot grow let's say a pancreas. Therefore when the human stem cells are implated at a very early stage, they human stem cells differentiate into the pancreas. Alot of research is being done looking into other medical applications such as using stem cells to heal people with parkinson's disease, I would recommend looking into it.

[Bender]

So they want to grow human organs inside an animal. In that case, the animal doesn't have any human DNA, only the organ to be harvested.

 

I guess this could become an ethical issue if you try growing a human brain inside an animal.

[Sir Salty]

Yes agreed, however, to get to that stage is sorta trial and error. Therefore, a crude way to put it, at first it will be scientists mixing human DNA with animal DNA and allowing a creature with both to develop to a certain stage and observing results. Also the human cells theoretically will differentiate into only the animal organ the has been genetically removed, however some human stem cells may also become other cells. Also no medical reason to grow human brains inside an animal ^^ but yes that would definately cause ethical issues aha.

Edited March 29, 2017 by Sir Salty

[Bender]

Are these assertions based on fact? If we just randomnly mix DNA, I think it is highly unlikely that the result would be viable or even develop before being rejected. Disabling the genes for the animal organ could have the same effect. I would not expect the animal to function with a human organ.

 

I would expect a decent amount of controle is required to even get any results.

Edited March 30, 2017 by Bender

[Sir Salty]

Are these assertions based on fact? If we just randomnly mix DNA, I think it is highly unlikely that the result would be viable or even develop before being rejected. Disabling the genes for the animal organ could have the same effect. I would not expect the animal to function with a human organ.

 

I would expect a decent amount of controle is required to even get any results.

Go look up so details on CRISPR-cas9, thats whats currently being used to genetically modify the animals. Also go read the BBC news article I posted in OP and perhaps its references. It is not quite as simple as randomly mixing DNA, and there is already clear scientific proof that the human DNA interacted with the animal DNA which was why it was so successful and got published.

Edited March 30, 2017 by Sir Salty

[ModernArtist25]

Can't humans just stick to 3d printing organs rather than making animals suffer?

[Bender]

If that works as wel: of course.