LONGECITY

Something I've been waiting for...

http://seattletimes....7_clones15.html

Sounds like this time it's for real. Not very efficient yet; takes lots of eggs, but that can probably be improved. I like how every time I turn around, it seems like SENS is getting closer.

One of the things I've always been curious about in regards to SCNT and the development of therapeutic applications for Type 1 Diabetes is how long the beta-cell replacement therapy would rejuvinate the patient.

From what I can tell, even in principle a SCNT "cure" would be suboptimal since the underlying cause of the disease is autoimmune malfunctioning. Inject new beta-cells and they're just going to get killed off again. The only true "cure" would come from future biotechnologies involving some form of highly advanced gene therapy.

Still, having beta-cell replacement therapy would be a major step forward in ameliorating diabetes. Ya can't argue with that.

It might be the case in some diabetics that the autoimmune dysfunction was a one-time event that eventually got better, but not until too many cells were trashed. Or not.. I'm just speculating. I'm also interested in seeing what happens when healthy people are infused with a couple hundred million pluripotent stem cells.

The problem is that the nuclear material from the donor is not at the same stage of life as the cytoplasmic material in the egg, and getting the two materials into rhythm can be exceptionally difficult.

For anyone curious about the specifics of these technical difficulties, try googling terms like "methylation" and "imprinting".

In case it was decided to do this with germline cells instead of somatic cells would there be a problem with the number of chromosomes?

It was suggested that we don't use germline cells for stem cell therapy because they only have 23/46 chromosomes.

A while back I referenced this Jaenisch video lecture, but it provides such a good overview of therapeutic cloning that I figure I'll post it again:

MIT World - Human Cloning and Human Rights: Promises and Perils

In case it was decided to do this with germline cells instead of somatic cells would there be a problem with the number of chromosomes?

It was suggested that we don't use germline cells for stem cell therapy because they only have 23/46 chromosomes.

??

The DNA from the germline is discarded with SCNT.

In layman's terms, SCNT is basically sucking out the genetic content of a germ line cell, inserting the genetic content of a somatic cell into it, and then zapping it with an electrical charge to stimulate the onset of development.

Technosophy,

OK then how does taking an existing germline cell (from the patient instead of a third party) and using that for autologous stem cell therapy compare to SCNT?

If you grant me a cloned beta-cell source, you might also want to grant me a cloned hematopoietic stem cell source. This is supposed to overgrow and replace the existing hematopoietic system, tolerizing it to any antigens carried by the new cell line. See e.g. resolution of allergies, graft rejection even by allogenic bone-marrow transplants in people, and ACT's 2005 "bovine hematopoietic engraftment" paper.

A while back I referenced this Jaenisch video lecture, but it provides such a good overview of therapeutic cloning that I figure I'll post it again:

MIT World - Human Cloning and Human Rights: Promises and Perils

Thanks!
There isn't enough exposure to Jaenisch's work out there. Reading some of his stuff changed the way I look at cellular biology.

Cool! I'm not very knowledgeable within this field, but these news seem like a really big step forward.

A while back I referenced this Jaenisch video lecture, but it provides such a good overview of therapeutic cloning that I figure I'll post it again:

MIT World - Human Cloning and Human Rights: Promises and Perils

Alright, that was a good introduction to therapeutic cloning Though I missed a more thorough explanation of the science involved, and (although they are mentioned) the biological and technological problems that need to be overcome before we can start using stem cells for therapy. For example, in the video, Jaenisch mentioned that nuclear transfer was still very inefficient, but he didn't really explain why. The video was recorded three years ago, so I would expect at least some progress in the field during that time.

Are there any (preferably free) up-to-date videos, websites, downloads, etc. that can provide a more in-depth scientific explanation of therapeutic cloning and nuclear transfer, and the biological and technological problems and obstacles associated with it, and how it would be used for therapy? Also, where is the SCNT research being done?

I just feel that I need a solid scientific introduction, that's all.

Note: I have heard, read and seen a lot about the political debate on this issue already, so I feel pretty well educated on that part.

how does taking an existing germline cell (from the patient instead of a third party) and using that for autologous stem cell therapy compare to SCNT?

This is called parthenogenesis. It can work in principle only for half the population (those who come with egg cells). It also doesn't seem to work well when the egg is from an elderly donor, and it's mostly the elderly who would be interested in these therapies after all. But even so, I think the idea still has lots of potential.

I'm trying to read through the scientific discussion. Just how important is this discovery? I was going to post this story a few days ago, but I figured it was likely a false-claim, or something meaningless. By the sounds of it, it sounds like an important finding. For the science laymen like myself, is this as good as it sounds?

I'm trying to read through the scientific discussion. Just how important is this discovery? I was going to post this story a few days ago, but I figured it was likely a false-claim, or something meaningless. By the sounds of it, it sounds like an important finding. For the science laymen like myself, is this as good as it sounds?

It means that now, at least in principle, you can create a new copy of any cell in your body, with your own exact genome. (Perhaps with an improved version of your genome, someday.) These cells might be used for all manner of repair/replacement problems. Repair of spinal cord injury is often mentioned, along with cures for Parkinsons and Diabetes. They might be useful in tissue engineering applications, as in building new organs. They should be useful for in situ tissue repair; there have already been cases where heart attack victims were substantially improved by injection of their own adult stem cells into the heart. It might be the case that systemic infusions of embryonic stem cells would seed large portions of the body with new cells, with stem cells differentiating magically according to signals they obtain from neighboring cells. (Or that might be a case of magical thinking overriding the complexities of development.)

But anyway, yeah, it's an important development. As far as being as good as it sounds... Well, things usually aren't as good as our wildest hopes. Most of the stuff I mention above has not been fully worked out, and will probably be pretty complicated in reality. Some of the hopes will probably fall flat, while we might discover some new things that no one has even thought of yet.

This is called parthenogenesis. It can work in principle only for half the population (those who come with egg cells). It also doesn't seem to work well when the egg is from an elderly donor, and it's mostly the elderly who would be interested in these therapies after all. But even so, I think the idea still has lots of potential.

John,

For the rest of us could spermatogonial progenitor cells (SPCs) be considered for parthenogenesis?

http://www.earthtime...how/110837.html

My expectations are molded with these types of provisions in mind. But as you've said, it's still important nonetheless. I expect there to be refinements to this method, as well as completely other methods of achieving similar results. I'm constantly trying to be an optimist, so news like this, while maybe not as good as it literally sounds, does open up more possibilities to more optimistic outcomes for the future.
Edited by G Snake, 21 November 2007 - 08:45 PM.

For the rest of us could spermatogonial progenitor cells (SPCs) be considered for parthenogenesis?

Considered -- sure. How likely is this to work -- I don't know, and I don't think anybody else does. There's lots more work done with egg cells, and so one can be a lot more confident there.

Considered -- sure. How likely is this to work -- I don't know, and I don't think anybody else does. There's lots more work done with egg cells, and so one can be a lot more confident there.

Are you aware of any research into ameiotic parthenogenesis? In my understanding of this term it means the the male uses its own genetic material to replace the female genetic material in the zygote.

Could this be a potential way to help get the benefits of SPC harvesting without the requirement for surgery?