Thomson is the leader of one of the teams that made the interesting scientific discovery which Bush modestly claimed was due to him.
Standing in the Way of Stem Cell Research
By Alan I. Leshner and James A. Thomson
Monday, December 3, 2007; Page A17
A new way to trick skin cells into acting like embryos changes both everything and nothing at all. Being able to reprogram skin cells into multipurpose stem cells without harming embryos launches an exciting new line of research. It's important to remember, though, that we're at square one, uncertain at this early stage whether souped-up skin cells hold the same promise as their embryonic cousins do.
Far from vindicating the current U.S. policy of withholding federal funds from many of those working to develop potentially lifesaving embryonic stem cells, recent papers in the journals Science and Cell described a breakthrough achieved despite political restrictions. In fact, work by both the U.S. and Japanese teams that reprogrammed skin cells depended entirely on previous embryonic stem cell research.
I would add more. The modification which makes adult cells act like stem cells involves adding genes with retrovirus vectors. Back before Bush decided to save blastocysts destined for the toilet, genetically modified cells in people were the big bioethical shibboleth. Frankly, even a rabid enthusiast like me would rather avoid combining gene therapy and stem cells.
Since stem cells differentiate (the point) it is hard to know if the insert will cause problems when the cell differentiates into this or that.
I have long supported putting herpes tK in along with added genes so that the resulting cells can be selectively destroyed with gancyclovir if necessary. More importantly so has my dad who was a member of a gene therapy advisory commission.
They ignored him and someone got a leukemia.
There is no need to add genes to make stem cells. The same result can be obtained by putting an adult cell's nucleus in a zygote whose nucleus has been zapped or removed (it's called cloning). This procedure can produce stem cells genetically identical to the patients cells with no added genes or virus vectors. I don't see any ethical difference.
Huh ! no difference ? Why ?
Well if the modified cells are really like embryonic stem cells it should be possible to grow a whole mouse out of them by grafting them on to a blastocyst* (it's been done check the latest Nobel prize). If it works in humans, the adult stem cells have the potential to develop into a human being. Since that is the absurd standard for calling blastocysts people, if the anti stem cell research fanatics were intellectually coherent and serious, they would denounce adult stem cell research as research on little baby people. And pigs would fly.
* update: Silly me, of course I meant to type morula not blastocyst. Got to work on my typing.