A year after Harvard University scientists began trying to create cloned human embryonic stem cells, they have been stymied by their failure to persuade a single woman to donate her eggs for the groundbreaking but controversial research.
The goal of the work is to create embryonic stem cells -- all-purpose formative cells that can develop into virtually any cell in the body -- that are genetically matched to a patient with a particular disease, such as diabetes. Studying such cells could give scientists new insights into the diseases and possibly lead to treatments.
"It's an important experiment and we can't do it," Kevin Eggan, an assistant professor of molecular and cellular biology at Harvard.
Without unfertilized eggs, scientists cannot create cloned embryonic stem cells through the conventional method. Called somatic-cell nuclear transfer, the procedure involves replacing the DNA in a donated egg with DNA extracted from a patient's cells. Scientists coax this new egg to grow for several days in a laboratory dish until it is an early embryo and stem cells can be obtained.
Over the last year, Harvard has spent tens of thousands of dollars on local newspaper ads in an attempt to recruit egg donors. Hundreds of women have responded to the ads, but none has followed through with donations, for a variety of reasons, Eggan said in an interview.
For one thing, egg donation requires repeated clinic visits and minor surgery under general anesthesia to remove the eggs from the ovaries. Women also face a small risk of ovarian hyperstimulation syndrome, an excessive absorption of fluids.
Despite those burdens, thousands of women give eggs to fertility clinics every year in the United States, for fees averaging about $5,000 per person. But a 2005 Massachusetts law makes payment illegal when eggs are used for research purposes.
"We think that is why people aren't participating, particularly when they know they can do exactly the same thing for another woman's reproduction, which is an equally lofty pursuit, and be compensated well," Eggan said.
Prohibiting payment is meant to insulate scientists from charges that they are coercing women into controversial research. "With respect to stem-cell research, there is so much at stake in terms of public confidence, that I think we're better off trying to do it without" paying for eggs, said Jonathan Moreno, a bioethicist at the University of Pennsylvania, who cochaired a committee of the National Academies of Science that recommended the policy in 2005.
But other ethicists see the law as unnecessary. When paying women for egg donation, "There does not seem to be any compelling reason for making a distinction between reproduction and research," said Bonnie Steinbock, a bioethicist at the University at Albany, State University of New York.
Ultimately the challenge of finding egg donors could become less significant if, as new research reported by Eggan yesterday suggests, there are ways around the problem. "That's really what led us to this work," Eggan said.