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Friday, Jan. 11, 2008
Inventor: nonembryo stem cells need controls
The Associated Press
New, easy-to-handle technology to create the equivalent of human stem cells from ordinary tissue like skin must be regulated, said an inventor of the technology.
Shinya Yamanaka, a Kyoto University scientist, said any ordinary laboratory can generate such cells, which could be used "in the near future" to make human eggs and sperm — a step on the way to creating a human clone.
"The technology is very simple," Yamanaka, who published his findings last fall at the same time a U.S. research team released similar results, said Wednesday in Tokyo. "You don't need any special equipment.
"We can do something bad by using that ability," he said. "That's why I think we need regulation."
The new technique reprograms human skin cells so they behave like embryonic stem cells, which can morph into all kinds of tissue, such as heart and nerve cells.
The results — also reached by a team at the University of Wisconsin-Madison — were hailed as a breakthrough because the new cells avoid the complex and highly controversial idea of extracting stem cells from cloned human embryos.
Yamanaka said his university was still exploring whether the new cells were subject to Japan's highly restrictive law on embryonic stem cell research. He said he hoped such tough restrictions don't apply, although new and effective rules will be needed to regulate the new technology.
Still, the technique — which has not yet been patented — faces important hurdles before it could be used to treat humans safely.
Yamanaka's team used viruses to convert skin cells to the new cells, called "induced pluripotent stem cells," or IPS cells. That method, however, carries the risk of giving recipients cancer, and scientists are hard at work looking for a method that avoids the use of viruses.
Another hurdle is time. It takes about three months to generate IPS cells and make them into specific tissue — far too long for spinal cord injury patients, for example, who typically need transplants within 10 days of their injury.
To counter that, Yamanaka envisions creation of public "banks" where IPS cells supplied by donors covering the span of gene types would be readily available for patients.
"We can cut down the cost of treatment, and we can shorten the process that is needed," he said.
The method could also allow doctors treating a particular patient to generate genetically matched tissue to figure out why the patient fell ill, screen effective drugs for treatment and test for side effects, Yamanaka said. |
