Wednesday, June 20, 2007

Excellent Stem Cell News

In April I wrote a couple of posts about stem cells (and one somewhat indrectly) where I based a good deal of my argument on what was (then) the limit of published scientific knowledge. The critical points were that
  1. We can't tell stem cells from normal ones except by seeing how they behave
  2. Adult stem cells only produce cells for special parts of the body and not generalized ones
Well the Instapundit informs me that point (2) may no longer be true. At TCS there is an article about the researches of Shinya Yamanaka who has now published a couple of papers, includng this one in Nature, that appear to show that adding a few proteins to a stemcell it becomes "pluripotent", i.e. able to generate all types of cells. Critically (and unlike a certain Korean stem cell researcher), the research he published last year has now been reproduced by a different lab so it seems like he has got something right. Of course we are still at the "baby steps" stage of research. Prof Yamanaka has got mouse cells to work and there is, as far as I can tell, some confusion about whether what he has produced are "normal" stem cells or some evil thing that will produce tumors and nothing else. There may also (I'm limited to reading abstracts) be some mystery about why the trick he uses works. If you MUST know what he does is "retroviral introduction of Oct3/4 (also called Pou5f1), Sox2, c-Myc and Klf4, and subsequent selection for Fbx15 (also called Fbxo15) expression" and some colleagues have a paper that may explain why it works.

Now all this is excellent stuff and may well allow us to ditch the idea of human embryo stem cell research, but it seems to me that the TCS article is written by a gentleman who is vehemently against research using human embryonic stem cells so I'm not going to take his word for it. Why do I think that you ask? well phrases like the one I quote below seem to be a tad hyperbolic:

Will this disruptive technology open up ethical avenues in the promising field of stem cell research, avenues which do not involve turning women into battery hens for their eggs and destroying embryos?

I also suspect that, contrary to what the article implies, researchers would greatly prefer to use processed adult stem cells to embryonic ones if they can. One good reason why is that it will be very very easy for researchers to get adult human stem cells, from for example a piece of skin or flesh from a biopsy, and they will therefore be far more numerous and varied, becasue to put it simply every researcher can get his own from himself, and hence discoveries will be less likely to be flukes and more likely to work with all humans and not just some. But the bad news is that until we understand why retroviral insertion of Oct3/4, Sox2, c-Myc and Klf4 works (and for that matter whether the same proteins work in human stem cells) we can never be sure that such modification is in fact safe. On the other hand the related positive news is that this may hold out the possibility that we figure out not just why adult stem cells aren't as flexible but also how stem cells differ from normal ones so that we can make every cell in a biopsy a stem cell.
(xposted at my own blog)

1 comment:

james higham said...

Excellent Stem Cell News

How many people would post a header like that? Come to think of it, the whole thing is pretty remarkable:

Prof Yamanaka has got mouse cells to work and there is, as far as I can tell, some confusion about whether what he has produced are "normal" stem cells or some evil thing that will produce tumors and nothing else.

I think I got the point here, L'Ombre:

so that we can make every cell in a biopsy a stem cell