Scientist Hopes For Stem Cell Success

Editor's note: The video of the rats shown at the beginning of our story "To Walk Again" was of an experiment conducted by reputable researchers. The study was peer-reviewed and published in the Journal of Neuroscience. We did not identify the researchers or their institution at their request. The study conducted by Dr. Hans Keirstead at the University of California, Irvine, was also peer-reviewed and published by the Journal of Neuroscience. Keirstead's study, as shown in the animation in our story, had similar results: paralyzed rats walking again. Video | Animation

To move the science forward, California allocated its own money to pay for stem cell research, luring some of the top scientists in the nation, who are doing cutting edge work that could change the way we treat disease. No image says more about the remarkable results that have been achieved so far than this one: laboratory rats whose hind legs were completely paralyzed — until they were injected with human stem cells. Remarkably, afterwards, the rats were able to walk again.

Now, Dr. Keirstead, a 38-year-old biologist at the University of California, Irvine, says he is ready to try the same thing in people paralyzed by spinal cord injuries. Pending FDA approval, correspondent Ed Bradley reports that would make him the first scientist in the United States to transplant embryonic stem cells into humans.

Keirstead has been quoted as saying that that every 100 years we have one major medical milestone and that this is one of those times. It's a pretty bold statement.

"I have never seen in my career a biological tool as powerful as the stem cells. It addresses every single human disease," says Keirstead.

That's because embryonic stem cells, which are extracted from embryos just five days after fertilization, are capable of becoming any type of cell in the body, can be grown in infinite numbers, and can replace cells that have been destroyed or damaged by disease or injury.

Dr. Keirstead says that for humans, about 20 million cells have to be injected. "That's the beauty of this cell type; you can make a lot of cells," he explains.

Suzanne Short has been closely watching Keirstead's work every step of the way. She was paralyzed from the neck down when a drunk driver crashed into her car 24 years ago. She meets regularly with Dr. Keirstead, and hopes to one day be treated with his stem cells.

Asked how she would react if she were told she was eligible for a clinical trial, Short says she'd jump at the chance. "I used to say I didn't want to be first but I'd be second. I think at my age now I'd be willing to go first."

What does she hope stem cells might eventually do for her?

"Whether I walk or not, I really don't care. And, yeah, if I do that's great," says Short. "But, I mean, if you could just wake up one morning and not have to wait for someone to come in my room and get me out of bed, I could at least transfer myself into my own wheelchair, be amazing. I'd be completely independent."

Short, a professional artist, is confident that it's not a question of if that will happen but when. That's because of what Keirstead has been able to accomplish with embryonic stem cells in just the past five years: he transformed them into a specific type of nervous system cell that is needed for the spinal cord to function properly.

He showed 60 Minutes an animation of what happened after he injected more than a million of those cells directly into the spinal cords of rats that were partially paralyzed.

"This is a video of an injured rat. The signal that's going from the brain down to the spinal cord controlling all of the muscles of the body are interrupted by a spinal cord injury," Keirstead explains.

The new cells he created traveled right to the damaged area of the spinal cord and wrapped themselves around the nerves there, enabling the signals to flow uninterrupted through the body. Six weeks later, the once paralyzed animals were able to lift their tails and they could walk.

What was the reaction in the lab when everybody saw that?

"We've been riding quite high for quite a long time now," Keirstead says, laughing. "It's tremendous in research to have something working so well."

Asked what would be considered success in humans, Dr. Keirstead says, "I think we could call this a dazzling success if we saw the smallest improvement in the ability of a human to do anything that they could not do. If they could move a single finger, I would call that a raving success. Let's hope it's a lot more."

Keirstead admits he is concerned about giving people false hope. "The fears of giving somebody false hope are real," he says. "We're not trying to come up with something to take you from zero capabilities to 100 percent. These are incremental advances. And it is experimental."

The clinical trial that Keirstead hopes to conduct will take place next year and would be in collaboration with Geron, the leading biotechnology company in the field. The trial would be only for people with newly injured spinal cords because his work shows they would be more likely to benefit.

He is also working to apply that research to people with long-term paralysis like Suzanne Short. While Keirstead has been widely praised for his work, he has also been criticized by some scientists for trying to rush his treatment into people.

Asked about the criticism that Keirstead is moving too fast, Short says, "I don't think he's moving fast enough. I wish there were 10 more of him to keep working. But, no, it'll happen some day. Hopefully I'll be around for it to happen."

Keirstead admits he is concerned about side effects when stem cells are put into humans.

"I'm very concerned and I'll be losing sleep, no doubt, when this first gets into humans," he says. "There is a potential for harm, this is a risky endeavor, like any clinical trial."

What's not known is whether embryonic stem cells will integrate and function in the human body as well as they have in animals, nor is it known what the side effects will be. Some research indicates that stem cells can form tumors or other abnormal cells. Still, most scientists have confidence in the enormous potential of stem cells to treat incurable diseases such as diabetes, Alzheimer's and, especially, heart disease, which is the No. 1 cause of death in the United States.

That's a trend Dr. Robert Robbins, chair of cardiothoracic surgery at Stanford University, is working to reverse.

The reason for his optimism can be found inside a Petri dish.

"These are the cells that go to make up the heart muscle cells," Robbins explains. "They all started out as cells from embryos. With the potential to develop into any type cell."

Robbins hopes to one day inject the cells, which actually beat like a heart, into someone whose heart has suffered some kind of damage.

In theory, those cells would then replace the damaged part of the heart.

Robbins and his team injected cells like those directly into the hearts of mice with severe cardiac disease. The researchers then tracked the cells and determined that they had stayed in the heart and that the cells were all beating in unison. After six weeks, the new heart cells had replaced the damaged ones, and heart function was restored to near normal.

Looking at the big picture, what's the significance of his findings?

"There's a lot of enthusiasm for this area of research," says Robbins. "There's great hope for patients that suffer from heart failure that may be too old or can't get a heart transplant. And a heart transplant is a big operation. You would much prefer having a therapy that you could go out of the hospital with just a band-aid on your leg versus having a big operation."

Robbins says he hears from a lot of heart patients inquiring about stem cell treatment. What does he tell those patients?

"Well, I would say that it's at least five to 10 years away before I think that we will have enough definitive data in animal studies that it will be safe to go forward with embryonic stem cells," says Robbins.

Scientists say the pace of research has been slowed down by President Bush's 2001 ban on the use of federal money to create new lines of embryonic stem cells. Researchers need those new stem cells to expand their work, because the existing lines are at least five years old and may have been weakened over time, limiting their value. However, extracting new stem cells destroys human embryos, which the president strongly opposes.

"How do you deal with people who feel that what you're doing is morally, ethically wrong, because in a sense you're destroying life to save life?" Bradley asked Dr. Hans Keirstead.

"I don't feel what I'm doing is morally wrong. I think the use of human embryonic stem cells is an ethical and responsible thing to do with tissue that would have been destroyed in the discards of a fertility clinic," Keirstead replied.

"But there are people who would say that that is life," Bradley said.

"So, let's use it instead of discarding it. Why discard it? If you think that that is a holy thing, then value it, treasure it and keep it. Use it for research and the betterment of lives, don't throw it away," Keirstead said.

In an effort to create a safe haven for embryonic stem cell research, in 2004 California voters passed Proposition 71, allocating $3 billion in state money to allow development of new stem cell lines. While that enticed some of the top researchers in the field to move to California, the money has not yet been released because of lawsuits challenging Proposition 71.

In the meantime, Dr. Arnold Kriegstein, head of stem cell research at the University of California at San Francisco, is raising $5 million in private money to build a brand new laboratory that duplicates facilities the university already has. It's necessary because scientists are only permitted to work with new embryonic stem cell lines if their lab does not receive any federal money.

Even if he already has things like microscopes, Petri dishes and refrigerators, he has to buy the same equipment again for the stem cell research.

"Absolutely. All the materials and supplies, all the consumable materials, everything that's involved in any of this work needs to be paid for through private funds," Kriegstein explains.

Kriegstein says that is one of the problems researchers face. "It's very costly and it's time-consuming, and it has been slowing down progress in the field," he says.

But there is one area of stem-cell research that is now ready for human testing and it may be the only chance that Joanna and Marcus Kerner have to save the life of their 6-year-old son, Daniel. The FDA recently approved a clinical trial using brain stem cells from fetal tissue to treat the rare and always fatal neurological disorder called Batten disease, which Daniel was diagnosed with a year and a half ago. The Kerners' doctor gave them the grim prognosis.

"He shook his head and said, 'I'm sorry there's no cure,' " Marcus Kerner recalls. "Suddenly, you're told your child is going to die this horrible, horrific, long prolonged death of blindness, loss of all motor skills, dementia and like a flower wilting."

If Daniel is among the six children selected for this clinical trial, he will receive an injection of neural stem cells from aborted fetuses that are several weeks more developed than embryos. Based on studies in mice, it's expected the transplanted cells will produce a crucial brain enzyme, and slow the progression of the disease.

"Are you at all hesitant about this? I mean, one, you don't know if it'll work. Two, you don't know if it's safe. It's never been done before," Bradley asked Marcus Kerner.

"He's going to die anyway, Ed. And I'd rather he go down fighting," Kerner replied, crying. " 'Cause he's a fighter, he's brave. And he wants to live."

Scientists will be closely monitoring the results of the clinical trial for Batten disease looking for clues that could help in the development of stem cell treatments for a variety of neurological disorders. They will also be awaiting the outcome in California of a court case trial set to begin Monday, Feb. 27, to determine whether to free up the $3 billion for embryonic stem-cell research that was allocated by Proposition 71.
By Michael Radutzky/Tanya Simon