So far, not a single person has been helped by human embryonic stem cells (search).
But in cramped university labs, a young neurobiologist with movie star good looks, a Carl Sagan-like fondness for the popular media and an entrepeneur's nose for profits is getting tantalizingly close.
Hans Keirstead is making paralyzed rats walk again by injecting them with healthy brain cells sussed from a reddish soup of human embryonic stem cells he and his colleagues have created.
Keirstead hopes to apply his therapy to humans by 2006. If his ambitious timetable keeps to schedule, Keirstead's work will be the first human embryonic stem cell treatment given to humans.
"I have been shocked, thrilled and humbled at the progress that I have made," Keirstead, 37, said in an interview in his University of California-Irvine office, which is dominated by a 4- by 8-foot collage of famous rock stars created by his artist brother. "I just want to see one person who is bettered by something that I created."
Keirstead has been turning stem cells into specialized cells that help the brain's signals traverse the spinal cord. Those new cells have repaired damaged rat spines several weeks after they were injured.
For the last two years, he has shown dramatic video footage of walking healed rats to scientific gatherings and during campaign events to promote California's $3 billion bond measure to fund stem cell work, which passed in November.
Keirstead and his colleagues are continuing to experiment with rats to ensure the injected cells do what they're supposed to without any side effects.
"You don't want toenails growing in the brain," he said.
Meanwhile, Keirstead and his corporate sponsor — Menlo Park-based Geron Corp. (search) — are designing the initial human experiments, which will test for safety and involve just a handful of volunteers. The volunteers likely will be patients who have been recently injured.
Keirstead's work was at first met by derision and disbelief at the Society of Neuroscience's annual meeting in 2002.
"We upset a lot of people," said Dr. Gabriel Nistor, who was the first researcher to join Keirstead's lab five years ago. "No one believed us at first." Keirstead and Nistor were stars at the same gathering in October, and their research will be published next month in a scientific journal.
Kierstead is as close as anyone in the stem cell research world could be to celebrity, and that can be dangerous in a profession noted as much for its petty jealousies of individual fame as it is for scientific breakthroughs. (Carl Sagan, the noted astronomer who for years hosted the PBS series "Cosmos," was denied membership in the prestigious National Academy of Sciences, a slight that his supporters insist was based on his mass appeal).
Reporters have beaten a well-worn path to Keirstead's lab. The fact that he's wealthy only adds to his growing luster.
Keirstead recently sold a biotech company he co-founded, unrelated to his stem cell work, in a deal that could be worth as much as $8 million.
"We all love Hans — for various reasons," giggled Karen Miner, whose advocacy organization helps fund Keirstead's work.
Miner and her colleagues at Research for Cure, based in Escalon in California's Central Valley, have contributed $170,000 over the last four years to the Reeve-Irvine Research Center where Keirstead works. The center is named for its founding donor, actor Christopher Reeve, who died in October of complications related to his paralysis.
"We all feel he is on the cutting edge of spinal cord research," said Miner, 53, who was paralyzed below the neck after an automobile accident 12 years ago. "I have to think it's the most promising thing out there."
She toured Keirstead's labs two years ago and watched once-paralyzed rats walk inside their cages.
"The adrenaline that I felt was almost enough to get me out of the chair," Miner said. "When you are sitting in a wheelchair and see those rats running around, all you can think is, 'I want some of those now.'"
Human embryonic stem cells are created in the first days after conception and are the building blocks of the human body. Scientists believe they will someday be able to coax stem cells to turn into healthy cells to treat a wide range of ailments, including diabetes, heart disease and spinal cord injuries. Many social conservatives who believe life begins at conception view the work as immoral because days-old embryos are destroyed during research.
Critics complain privately that Keirstead is beholden to Menlo Park-based Geron, which claims a Microsoft-like grip on any commercial stem cell market that emerges.
Geron funded the work of University of Wisconsin researcher Jamie Thomson, who discovered human embryonic stem cells in 1998, and the company funds Keirstead's lab at $500,000 a year. Geron owns the commercial rights to any drug Keirstead may develop.
Keirstead doesn't apologize for his funding source, which he said is more generous than he could have expected from the federal government and with fewer research restrictions. He said he's not interested in profits, but rather in speeding the development of new spinal cord treatments.
And he has an answer for those who say he's moving too fast and that his experiments with rats are dangling false hope before the 15,000 people paralyzed in the United States each year.
"This is extremely promising," Keirstead said. "Why the hell would we wait?"