Thursday, October 05, 2006

Hope, unfulfilled promises on stem cell work

By Sally Lehrman | October 1, 2006

IN AUGUST, Advanced Cell Technology reported in the journal Nature that it had created embryonic stem cells for the first time using a technique that avoids destroying an embryo. Journalists leapt on the news because it meant researchers might sidestep moral objections that had plagued the technology. Just the previous month, President Bush had vetoed Congress' modest extension of federal funding for the science.

But despite news of a breakthrough at the company's lab in Worcester, the work didn't live up to the buzz. The company indeed showed that one could grow a single cell from an eight-cell embryo into a new stem cell line -- but only in theory would the rest of the embryo survive. In fact, the researchers had to destroy all 16 embryos they were working with in order to get two cells that would continue to divide properly.

Journalists blamed their confusion on overblown statements in both the company press release and Nature's media advisory. But one might expect more skepticism about a field that has shown itself prone to hyperbole.

Politicians and voters need to be cautious, too. In Massachusetts, Democratic gubernatorial candidate Deval Patrick wants to issue bonds to support stem cell research. The field ``provides hope," his policy book carefully notes, ``to those suffering from Alzheimer's disease, diabetes, multiple sclerosis or any number of other chronic genetic ailments."

But California's experience should be a warning to those expecting quick progress. In 2004, voters passed an initiative to provide $3 billion to embryonic stem cell research on the promise that the technology could ``cure" a stunning 70-plus diseases. But legal and legislative battles over conflicts of interest and public accountability stalled research grants for the next two years. Finally, in July, Governor Arnold Schwarzenegger lent $150 million from the state general fund to get research grants started.

Research into embryonic stem cells has great potential. These cells seem able to renew themselves continuously and produce any type of specialized cell necessary to restore damaged tissue. But learning how to create them efficiently and grow them predictably is the first of many technical challenges.

Researchers must figure out how to direct them to integrate properly into the body, too. Certain diseases, including Alzheimer's, aren't candidates for stem cell treatment until the underlying condition is better understood.

Scientists in many fields have sometimes exaggerated the importance of their work. But stem cell researchers seem uniquely inclined toward dramatic claims.

In 2004, Korean scientist Hwang Woo Suk faked the landmark achievement of extracting the first stem cells from a cloned human embryo. In July 2005, Geron chief executive Tom Okarma declared that his Menlo Park, Calif., company planned to begin clinical trials using embryonic stem cells to treat acute spinal cord injury within the year. Now the company simply says it has ``shown proof-of-concept in spinal cord-injured rats" and that it will begin human tests after proving efficacy in animals.

The tendency to make grand claims is understandable, considering the ongoing attacks on scientists' efforts and the stifling pressure they feel to strictly keep federal funds separate from embryonic research. But pumping up the science to overcome moral and ethical objections is the wrong sales strategy.

Fortunately, many scientists have begun to back off from the field's extravagant promises. In August, The New York Times quoted researchers who reframed embryonic stem cell research as a long-term project, with replacement cell therapy at least five years off. Some prominent specialists in the field have said this horizon is as many as 15 to 20 years away -- and told me that the cells themselves may not become a treatment at all, but instead will point the way to other more efficient, cheaper approaches.

Embryonic stem cells may help answer some of the most important questions in human biology. When I interviewed him last year, Gordon Keller, who studies how to direct these cells to specialize into blood, cardiovascular, liver, and pancreatic cells, urged his colleagues to stick to the facts. ``We need to be careful that we're not overselling the immediate potential," said Keller, who becomes director of the McEwen Centre for Regenerative Medicine in Toronto next year.

In a 2005 survey of 2,200 Americans, the Johns Hopkins Genetics & Public Policy Center found that two-thirds of respondents supported or strongly supported embryonic stem cell research. But by telling tall tales about imminent cures, embryonic stem cell researchers squander their credibility. Why risk losing the public trust? The basic science is thrilling enough.

Sally Lehrman reports on health and science for Scientific American, the radio program ``The DNA Files," and other media.