SUSAN DENTZER: Biologist Jamie Thomson is a founding father of the controversial field of human embryonic stem-cell research. He was the first scientist to remove these unique cells from days-old human embryos, and then grow them into colonies of cells, called lines.
Here at his lab at the University of Wisconsin at Madison, Thomson is now trying to unlock the secrets of these prototype cells. They ultimately grow into all of the body's tissues and organs.
DR. JAMIE THOMSON: We're asking what's special about these cells, how come they have this potential to form everything in the body, and what are the basic molecules that make them decide to become themselves versus something else?
SUSAN DENTZER: Obtaining embryonic stem cells destroys the tiny dot-sized embryos, which is why many object to it. But Thomson and his fellow stem-cell scientists say their research will revolutionize medicine and save lives. Now they're pressing for changes in Bush administration policy that limits federal funding to research on specified cell lines.
DR. JAMIE THOMSON: If the same policy goes forward for another four years, it will seriously impact this research, and people will suffer because of it.
SUSAN DENTZER: At the recent Democratic National Convention, Ron Reagan, Jr., son of the former president, called for drastically expanding embryonic stem-cell research; so did President Bush's challenger, Democrat John Kerry.
SEN. JOHN KERRY: What if we find a breakthrough to Parkinson's, diabetes, Alzheimer's and AIDS? What if we have a president who believes in science so we can unleash the wonders of discovery like stem-cell research and treat illness for millions of lives?
SUSAN DENTZER: White House officials have met recently with congressional lawmakers from both parties, who want to see changes in the president's policy. As yet, though, no shift has been announced. Election-year politics aside, how much scientific progress really has occurred under President Bush's policy, and what are the scientific arguments for lifting restrictions on the research? A little history helps to illuminate.
Since 1996, Congress has voted each year to ban federal funding for research that harms human embryos. So the Clinton administration did not fund embryonic stem-cell research, and early on, President Bush vowed not to as well. But on August 9, 2001, the president surprised many by announcing that federally funded research could go forward under certain circumstances.
PRESIDENT GEORGE W. BUSH: As a result of private research, more than 60 genetically diverse stem-cell lines already exist. They were created from embryos that have already been destroyed, and they have the ability to regenerate themselves indefinitely, creating ongoing opportunities for research. I have concluded that we should allow federal funds to be used in research on these existing stem-cell lines, where the life- and-death decision has already been made.
SUSAN DENTZER: In effect, the president's action created a safe harbor for federally funded embryonic stem-cell research, although a narrow one. Yet even with the policy's limitations, Thompson says, it has allowed science to advance.
DR. JAMIE THOMSON: I was very grateful that a compromise was found where research dollars could flow in this direction. And at the time, although it is a compromise, I was fairly muted in the criticism of that compromise, because there were a lot of people really working hard to see that this research gets funded.
SUSAN DENTZER: The U.S. National Institutes of Health, the world's largest biomedical research agency, was charged with carrying out the president's stem-cell research policy. Dr. Elias Zerhouni is NIH director.
DR. ELIAS ZERHOUNI: One of the things that I was asked to do was to make sure that all the progress that can be made in stem-cell research is made, and that was directly from President Bush.
SUSAN DENTZER: Zerhouni says a key goal was ensuring that scientists got access to all the authorized cell lines. A line is a series of genetically identical stem cells derived from a single embryo.
Although the president had cited 60 such lines in his 2001 speech, far fewer turned out to be viable. In fact, for a time in 2002, only one line was available for broad distribution. Zerhouni says the NIH got in touch with stem-cell labs around the world, and offered to help.
DR. ELIAS ZERHOUNI: We said, if you're willing to expand those lines and make them widely available, we'll be willing to fund the culture facilities, essentially, and we did. And that's how we went from one line in 2002 to 21, and soon 23.
SUSAN DENTZER: Today it's fairly easy, although not cheap, for scientists to obtain the authorized lines. We saw that in a visit to Wisconsin's Wicell Research Institute, a nonprofit organization that houses the five eligible lines created by Jamie Thompson. Lab technician Daisy Manning told us that for a fee of $5,000, authorized scientists can obtain two vials of a cell line-- about a million stem cells are in each tube.
DAISY MANNING: We go into our freezer, remove two vials, put them on dry ice and ship them via FedEx, and you'll have your cells overnight.
SUSAN DENTZER: Zerhouni says NIH now plans to make things even easier, and much cheaper, by creating a government-funded one-stop shop where researchers could get all 23 authorized lines.
DR. ELIAS ZERHOUNI: We've funded about $10 million in 2002, $25 million in 2003 alone, and growing. As we go forward we're making commitments, we're expending the investments. The president has not banned any funding for, in terms of the amount, has not limited the amount of funding that we could dedicate to this area of research.
SUSAN DENTZER: NIH itself now has nine labs on its Maryland campus tackling the most basic questions about embryonic stem cells. Among other things, they're looking at which genes control these cells, and which chemical signals cause them to differentiate. Dr. Ronald McKay runs one of those NIH labs.
DR. RONALD McKAY: You can make beautiful neurons that work incredibly.
SUSAN DENTZER: McKay especially wants to help patients with Parkinson's Disease, in which brain cells that produce the neurotransmitter dopamine die off. That leads to familiar Parkinson's symptoms such as tremors, and eventually, to death. McKay and his research team recently took stem cells from mouse embryos, then turned them into dopamine-producing cells. You then put them back into rats that had been engineered to have a form of Parkinson's. What happened then?
DR. RONALD McKAY: Well, the rats, as it were, get better. I mean, they don't become perfect, but they get better. A lot of their behaviors get much better. So, for example, one of... the animals are given the disease in one half of their brain, and if you make the animal a little hungry, then it will reach out for a pellet of food. And, in fact, quite remarkably, our data show that the injured side recovers.
SUSAN DENTZER: McKay and his team have since shown that human embryonic cells can also be turned into these dopamine neurons. Scientists will now be able to study them to figure out what goes wrong in Parkinson's, and one day, possibly transfer them into diseased brains.
We asked McKay how fast these advances could come with the Bush policy in place. He turned the question around, and told us the rapidly evolving science will drive policy change.
DR. RONALD McKAY: There will be an absolutely overwhelming moral case for developing new policies as the technology demands different types of cells, different types of manipulation of the cell.
SUSAN DENTZER: One example may be at the University of Wisconsin. There, surgeon Jon Odorico now treats diabetes patients by transplanting insulin-producing pancreas cells from cadavers. But here in his lab, he's also working on turning embryonic stem cells into those very same pancreatic cells.
DR. JON ODORICO: You're talking about 30,000 new Type I diabetics, or more, every year in the U.S. And the numbers of organ donors in the United States, human cadaver organ donors, is about 6,000 or so, 8,000. It doesn't even come close to meeting the need.
SUSAN DENTZER: Odorico says the Bush policy forbids certain experiments his team would like to perform to advance the science and possibly produce cell-based treatments for patients.
And still other scientists are frustrated that they can't use federal funds to experiment with literally hundreds of cell lines created since the cutoff date in 2001. Almost 100 of those lines are here at Reproductive Genetics Institute, an in-vitro fertilization clinic in Chicago. Dr. Yury Verlinsky is RGI's director.
DR. YURY VERLINSKY: These are storage containers where we keep our stem cells.
SUSAN DENTZER: Verlinsky's clinic helps couples who are carriers of genetic diseases bear normal children.
RESEARCHER: In this embryo, we have two chromosomes, one paternal, one maternal...
SUSAN DENTZER: Many parents have donated their surplus embryos, which the clinic has used to create the new stem-cell lines. Verlinsky says that's making valuable scientific use of embryos that probably would otherwise be thrown away.
DR. YURY VERLINSKY: It's unique material. It shouldn't be discarded.
SUSAN DENTZER: Verlinsky told us he's heard from scientists eager to study 12 cell lines the clinic made from genetically defective embryos. The scientists want to use them to gain a better understanding of diseases like muscular dystrophy.
RESEARCHER: You know, most of these people should all be yeses.
SUSAN DENTZER: That persuaded congresswoman Diana DeGette of Colorado. She's teamed up with 185 of her fellow Democrats, and 30 Republicans, to sponsor new legislation. It would allow federal funding of research on new stem-cell lines created from discarded embryos at I.V.F. Clinics like R.G.I.
REP. DIANA DeGETTE: We've really stifled the research in its broad applications, in its infancy, just when we need to be supporting research.
SUSAN DENTZER: But pro-life lawmakers like Republican Congressman Dave Weldon of Florida say they'll fight any move to change federal policy.
REP. DAVE WELDON: The Bush policy needs to be kept in place, and private dollars should be used to fund this research, and then demonstrate that it really has the promise that they claim it has.
SUSAN DENTZER: And in fact, broad efforts are afoot to conduct embryonic stem-cell research privately, outside the federal constraints. In California, voters will decide in November whether to spend $3 billion in state funds on stem-cell research over the next decade.
And universities, including Harvard and Stanford, have set up their own privately funded stem-cell research centers. They hope to exploit as soon as possible all the potential of these unique cells.
JIM LEHRER: To view extended interviews with people featured in this segment, please go to our Web site at pbs.org.