A mere speck nestled in the eye of a needle, a five-day-old embryo (photographed using an electron microscope) contains controversial stem cells.
By Rick Weiss
Stem cell research has been living up to its reputation for being fast-paced. In the few weeks since the July National Geographic cover story went to press, several important advances were reported—along with some significant political milestones.
On May 19, a team of South Korean researchers led by Woo-Suk Hwang of Seoul National University announced it had created 11 human embryos that were genetic twins of patients with various diseases and had successfully extracted stem cells from those embryos—the first important steps toward therapeutic cloning. Most important, they achieved the feat with remarkable efficiency. When the same team became the first, in 2004, to derive a line of stem cells from a cloned human embryo, they reported that they had needed almost 250 human eggs to get just one embryo healthy enough to generate the precious cells. This time it took only 17 donated eggs, on average, to get each line of cells—a more than tenfold increase in efficiency thanks to modest changes in technique. It's not unusual to get about that many eggs from a single cycle of ovarian stimulation of the kind routinely performed for fertility purposes. That means that, for the first time, an already accepted medical procedure has the potential to create for a patient a self-replenishing colony of genetically compatible stem cells. Suddenly, therapeutic cloning became much less hypothetical, and the international stakes to develop such therapies got raised even higher as the Korean government announced it would pump even more money into the endeavor.
On the same day, Alison Murdoch, a fertility doctor at Centre for Life in Newcastle, England, announced that she had at last succeeded in creating a cloned human embryo using the less-than-perfect eggs she is currently allowed to use under British regulations. The difficulties she has had, she said, suggest there are great advantages to using fresh eggs, and she hinted that Britain's Human Fertilisation and Embryology Authority may have to allow scientists to use healthy fresh eggs if that country is to keep abreast with developments in countries such as South Korea.
On the political front, the U.S. House of Representatives made history by passing the Stem Cell Research Enhancement Act of 2005, which would loosen the restrictions on federal funding of stem cell research imposed by President George W. Bush in August 2001. The 238-to-194 vote included 50 Republicans, despite Bush's threat a few days earlier that he would veto the bill if it came to his desk. Now it is up to Senate Majority Leader Bill Frist, a surgeon, to decide if and when he will bring the identically worded Senate version of the bill to the floor for a vote. Last year, 58 senators signed a letter to Bush asking that he loosen his rules, which indicates there is an excellent chance the Senate would pass the bill. As of this writing, a veto by Bush would be the first of his presidency and it remains unclear if Congress has enough votes to override.
If current research trends continue, however, perhaps the ethical and political problems surrounding stem cell research will succumb to a technical solution. At least three teams of researchers in the United States and Australia have recently reported encouraging results suggesting it may be possible to generate embryonic stem cells—or at least cells that are functionally equivalent to embryonic stems—without having to create or destroy embryos in the process. Several hurdles remain. But the work strongly suggests that the fantasy of someday being able to turn ordinary cells—from, say, a person's skin—into personalized stem cells capable of becoming replacement tissues for various ailing organs may not be so many years away.