Stem Cell Debate Drives Alternatives

Nov. 7, 2006 - Researchers in the U.S. and elsewhere are finding ways to get around the ethical roadblocks to embryonic stem cell research.

And at a forum in Washington this week, experts are discussing some of the most promising strategies.

Congress -- with the backing of a majority of Americans -- passed a bill earlier this year removing the strict limits on federal funding for embryonic stem cell research. That bill would have cleared the way for government-sponsored research on the stem cells plucked from embryos left over at fertilityfertility treatments.

But President Bush blocked the measure, citing a belief -- shared by many religious conservatives -- that the government should not promote research that destroys human embryos for the sake of harvesting their stem cells.

However, such research remains a hot topic in Washington and is sure to resurface after Tuesday's elections.

In the meantime, scientists are busy looking for ways to harvest or create stem cells without harming human embryos or asking women to donate their eggs.

"We don't need any eggs or embryos at all," says Shinya Yamanaka, MD, a professor at the Institute for Frontier Medical Sciences in Kyoto, Japan.

Yamanaka describes his lab's early successes in mice creating stem cells from adult cells. His research involves isolating two dozen chemicals that give embryonic stem cells their ability to grow into nearly any tissue in the body.

That property, called "pleuripotency," is what makes scientists think stem cells can be coaxed to form new tissues that could help cure Parkinson's and other diseases.

The Japanese researchers found that four of the chemicals, in the right mixture, transformed connective tissue cells from adult cells into pleuripotent cells Yamanaka says are "indistinguishable" from embryonic stem cells.

Still, significant problems remain.

"I have to point out, the efficiency ? is very low," Yamanaka today told the scientific conference hosted by the Institute of Medicine. Only one in 1,000 attempts to transform adult cells into stem cells was successful.

Also, the cells formed tumors when implanted in mouse tissue -- a significant roadblock to using such cells for human treatments.