By Tom Still
MADISON – It’s an understandable question: If human embryonic stem cells can be produced by “reprogramming” the genes in a person’s skin cells, then why continue to pursue research involving stem cells that come from human embryos that must be destroyed in order to gather them?
Now that a team from the Harvard Stem Cell Institute has turned ordinary skin cells into what appear to be embryonic stem cells, some people will push to discontinue the “traditional” process of manipulating human eggs. Critics of the process pioneered by UW-Madison scientists will argue it’s unethical to use human embryos to create stem cells when other pathways exist.
If only it was that simple. While the Harvard breakthrough deserves to be pursued by scientists elsewhere, it would be a mistake to shift all the hopes and dreams of stem cell research into one experimental method. That’s not how science works.
Exploring multiple ways to create and grow human embryonic stem cells – the building blocks of human life – is too important to be left to one line of research. That’s just as true for the process established in 1998 by UW-Madison developmental biologist James Thomson and his team as it for research involving adult stem cells, stem cells from placentas and umbilical cords, or the latest discovery involving skin cells.
The discovery process surrounding stem cell research involves a variety of options, with scientists in different places checking and cross-checking the work of others in what is still a relatively young field. If a scientist at Harvard figures out how to transform a skin cell into a hybrid stem cell, you can bet scientists elsewhere will be trying to replicate the work and test its applications.
The technique announced last week uses laboratory-grown human embryonic stem cells – such as the ones President Bush has already approved for use by federally funded researchers – to reprogram the genes in a person’s skin cell, turning that skin cell into an embryonic stem cell itself.
The advantage is that the hybrid stem cell carries the DNA of the person who provided the skin cells. That means – in theory – any tissue grown from those cells could be transplanted back into the donor without much risk of rejection.
The disadvantage is the same: Because it carries the DNA of the donor, most scientists believe the excess DNA must be removed before the hybrid, or “fusion,” cells could be coaxed into growing into a liver, a pancreas or some other body part.
“If this stuff proves to work, that’s wonderful,” said John Gearhart, a stem cell researcher at Johns Hopkins Medical Institutions in Baltimore, Md. In an interview with the Washington Post, Gearhart said the extra DNA remains “problematic.”
“We’re just not there yet, and it’s going to take a long time to demonstrate that. Meanwhile, other techniques already work well, so let’s get on with it,” Gearhart said.
That attitude probably summarizes the outlook of many scientists. New techniques are certainly worth exploring, but work must continue on processes that are already known to work. Federal, state and private research dollars are too scarce to abandon the tried and true on the basis of very preliminary evidence.
The skin-to-stem-cell announcement demonstrates the importance of letting researchers do what they do best – research. Science itself will determine what pathways are the most feasible, the most economical and, in the long run, the most ethical. When it comes to science, the best policy is to let a thousand flowers bloom in hopes that a few will also bear fruit.
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