The Thomson article is online (abstract is free, article is behind a pay wall), but I haven't had a chance to read it.
In the meantime, Science Magazine has a news article on both the publication from Wisconsin's Thomson and the previously discussed Takahashi/Yamanaka article in Cell.
Be sure and read the last sentence!!!!
Now the race to repeat the feat in human cells has ended in a tie: Two groups report today that they have reprogrammed human skin cells into so-called induced pluripotent cells (iPCs). In a paper published online in Cell, Yamanaka and his colleagues show that their mouse technique works with human cells as well. And in a paper published online in Science, James Thomson of the University of Wisconsin, Madison, and his colleagues report success in reprogramming human cells, again by inserting just four genes, two of which are different from those Yamanaka uses.
Thomson's team started from scratch, identifying its own list of 14 candidate reprogramming genes. Like Yamanaka's group, the team used a systematic process of elimination to identify four factors: OCT3 and SOX2, as Yamanaka used, and two different genes, NANOG and LIN28. The group reprogrammed cells from fetal skin and from the foreskin of a newborn boy. The researchers were able to transform about one in 10,000 cells, less than Yamanaka's technique achieved, Thomson says, but still enough to create several cell lines from a single experiment.
Although promising, both techniques share a downside. The retroviruses used to insert the genes could cause tumors in tissues grown from the cells. The crucial next step, everyone agrees, is to find a way to reprogram cells by switching on the genes rather than inserting new copies. The field is moving quickly toward that goal, says stem cell researcher Douglas Melton of Harvard University. "It is not hard to imagine a time when you could add small molecules that would tickle the same networks as these genes" and produce reprogrammed cells without genetic alterations, he says.
Once the kinks are worked out, "the whole field is going to completely change," says stem cell researcher Jose Cibelli of Michigan State University in East Lansing. "People working on ethics will have to find something new to worry about."
(edited November 21, 2007 to adjust the title. I over reacted in calling this statement and "insult.")
4 comments:
As to that last sentence, and just for the record, there are a great many ethicists working on a great many issues that have nothing to do with stem cells. In fact, more than a few ethicists are irritated with the domination of the stem cell debate given that many feel there are much more pressing ethical issues facing clinical practice and research than stem cells.
(This is not to say that the issue is insignificant, just that the amount of discussion on the topic is out of proportion to it's actual significance to people's health).
--Daniel Goldberg
www.medhumanities.org
Hopefully the rhetoric will die down, now. I know that the pro-life crowd would breathe a sigh of relief if we didn't have to continually block attempts to use our tax funds for unethical research. Maybe we could pay attention to nanotech or artificial intelligence. (I'm worried that AI will emerge when text and instant messaging, YouTube and Google reach a critical threshhold. The Moon got Mike, I'm afraid we'll get Borat or SpongeBob.
The negative stigma surrounding human embryonic stem cells has served to force researchers to forget about truly exploring therapeutic techniques and focus almost exclusively on finding other avenues of stem cell harvesting. It is impossible to say just how drastic of a setback this was. Now that a new technique has been developed, research into this area can finally continue. Who knows, had research into how to use and direct differentiation of pluripotent cells not been stifled, we may already know exactly how to utilize these iPS cells to produce treatments.
Ethicists should be watch the video contained in the supplementary materials of Takahasi et al, and maybe then they would better understand the therapeutic potentials of stem cell research.
Perhaps ethicists can focus now on blasting the in vitro fertilization clinics that discard excess embryos, rather than attacking advances in the field of medical research. Or perhaps more likely, they will attack the individuals who are infertile and forced resort to IVF.
There is no "stifling," despite the reactionary party line cliches' like your's, Anonymous. Thomson did his basic research with federal funding and on embryonic stem cells. There was no funding at all prior to 8/2001.
ESC's derived from non-related human embryos aren't patient-specific like cells from the patient herself. They would only be available for the rich who can afford to pay for the oocytes - when and if humans are cloned - and we'll still need to develop *adult* progenitors or stem cells to use in actual post-natal people.
On the other hand, over the last 6 years, the bulk of the basic molecular biology has been done in animal cells, as most medical research has always been done. There are many avenues for PhD candidates to pursue - proteins, molecules, transcription factors and those uses you mention and that Jaenisch and others are working on.
Claiming empathy for the infertile after you call for the destruction of the children they go to such lengths to create - ignoring the realities of informed consent - is ironic, Anonymous.
It sounds as illogical as attacking the men and women who travel to China to buy organs harvested from prisoners on death row. We should go after the marketers, not the desperate people they exploit.
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