August 22, 2005
The ESC Replacement HypeTopics: Stem Cells
Numerous news sources report that scientists have turned "ordinary skin cells into what appear to be embryonic stem cells--without having to use human eggs or make new human embryos in the process." A Reuters headline, for example, reads "Scientists create embryonic cells from skin cell" and other articles suggest "Research May Sidestep Ethical Concerns Over Stem Cells." CBS calls the research a "Stem Cell Workaround" and the Financial Express asserts Stem cells sans human embryos possible!
Have Harvard researchers developed a source for embryonic stem cells that does not require the destruction of human life. Well, not quite. Amid the hype are more realistic articles reporting that the hybrid cells were derived from embryos that were previously destroyed:
The Harvard researchers used laboratory grown human embryonic stem cells - such as the ones that President Bush has already approved for use by federally funded researchers - to essentially convert a skin cell into an embryonic stem cell itself.Harvard's press release tells a much more qualified story (emphasis mine):
Now researchers must figure out how to remove the genetic information that was contributed by the embryonic cells in order to help the hybrid cells "differentiate," or grow into another type of tissue that can be used to treat disease.
A new study by Kevin Eggan, Douglas Melton, and colleagues offers hope that it might be possible in the future to produce embryonic stem cells without using human embryos. The Harvard Stem Cell Institute researchers will report in the Aug. 26 edition of the journal Science that it may be possible by fusing two cells together to some day produce cells with the properties of embryonic stem. The researchers caution, however, that many daunting challenges must still be overcome and the promise of their work should not be seen as a reason to slow present research efforts.And, while the hybrid cells have many of the characteristics of embryonic stem cells, "The authors conclude that human embryonic cells have the ability to reprogram adult cell chromosomes following cell fusion."
I noticed this as well:
Researchers caution, however, that like many other nascent therapies that initially seemed promising, stem cells may never live up to their promise.And, there is this issue:
Because it involves the fusion of a stem cell and a person's ordinary skin cell, the process leads to the creation of a hybrid cell. While that cell has all the characteristics of a new embryonic stem cell, it contains the DNA of the person who donated the skin cell and also the DNA that was in the initial embryonic stem cell.Finally, consider the following quote:
"Their data are certainly very good . . . and quite significant," said John Gearhart, a stem cell researcher at Johns Hopkins Medical Institutions. But the extra DNA "is problematic."
``This technique isn't ready for prime time,'' said Harvard researcher Kevin Eggan, an assistant professor of molecular and cellular biology at Harvard, who labeled the new procedure ``the first steps down an uncertain road.''
Yes, the research is "interesting" but given the problems with existing ESC lines one has to wonder how it will ever lead to a true "replacement" for embryonic stem cells.
Posted by tim at August 22, 2005 12:57 PM
Articles Related to Stem Cells:
- The ESC Replacement Hype - Aug 22, 2005