There's a companion article in the NYTimes as well, with quotes from Dr. Fred Gage, "In Early Experiments, Cells Repair Damaged Brains": nytimes.com
NEW ORLEANS, Nov. 6 — Researchers meeting here this week are reporting startling results from experiments to repair damaged brains. They are telling of plucking immature cells out of recently fertilized eggs, fetuses, the skin on a human scalp or — perhaps even more amazingly — from the brains of people who had recently died, and growing those cells in a dish. Then they have transplanted the cells back into damaged animal brains.
The transplanted cells, which are types of stem cells, migrate to the site of damage and release factors that ameliorate or may even replace dead tissues.
Such therapies are now working in a variety of animal experiments and are on the horizon for most major human brain diseases, including cerebral palsy, mental retardation, strokes, tumors, head trauma, spinal cord injury, multiple sclerosis, Lou Gehrig's disease, Alzheimer's disease, Parkinson's disease and scores of less well known neurological defects.
Nevertheless, scientists say that they still do not understand the basic biology of this process, and that huge hurdles still remain. For example, it is not clear if stem cells are making the right connections inside the brain or if they will even survive over the long term. Moreover, the field is threatened by religious and political arguments about abortion.
Among the scientists who have been reporting laboratory successes is Dr. Ira Black, a neuroscientist at the Robert Wood Johnson Medical School in Piscataway, N.J.
A few months ago, when Dr. Black reported that stem cells in human bone marrow could be transformed into stem cells that worked in the brain, "people told us that it was simply impossible," he said.
"We replied, yes, but we have created a miracle," said Dr. Black, one of the researchers gathered here at the annual meeting of the Society for Neuroscience. "Biological dogma has to be rethought."
Dr. Fred Gage, a neuroscientist at the Salk Institute in La Jolla, Calif., said: "People are doing fantastic experiments that no one believes are possible. And then others go out and repeat the experiment. It's amazing."
Dr. Jeffrey Rothstein, a neuroscientist at Johns Hopkins University in Baltimore, said, "It's like we're injecting a fountain of youth."
One of the best sources of human stem cells is the many leftover frozen embryos from fertility clinics. These cells do not involve abortion and can now be used in federally financed research, according to a recent decision by the National Institutes of Health.
But on the eve of the elections, scientists here voiced concern about opposition among Republicans to stem-cell research, and some expressed fear that a Republican administration might effectively stop the research by halting federal financing.
In an eloquent and emotional speech, the actor Christopher Reeves told a Sunday evening session of neuroscientists that he sometimes wished he were a rat so he could get the latest treatments for spinal cord injury. Mr. Reeves was paralyzed from the neck down in 1995.
The latest animal experiments described at the meeting include implanting embryonic stem cells into rodents with head trauma similar to the injuries that debilitate hundreds of thousands of people each year.
The cells are implanted near the injury or on the opposite side of the brain, said Dr. Tracy McIntosh, a neuroscientist at the University of Pennsylvania. In three months, 80 percent of the animals regained the ability to move their bodies smoothly. Tests showed that the stem cells had migrated to the site of injury, even if inserted far away, and were viable.
Similar results are being seen in animals with versions of Lou Gehrig's disease, Alzheimer's disease, multiple sclerosis, stroke, spinal cord damage, stroke and Parkinson's disease, the researchers said. Cells migrate and carry out rescue missions.
Methods are being developed to coax stem cells from various tissues into becoming specialized brain cells, said Dr. Ron McKay, a neuroscientist at the National Institute of Neurological Diseases and Stroke.
Dr. McKay's laboratory has developed a technique for making the neurons that are specifically missing in Parkinson's patients.
Dr. Gage described success in extracting human stem cells from fresh cadavers, whereas other researchers have found them in the human scalp. It looks as though most tissues in the body have small pools of stem cells that exist in order to carry out minor, continuing repair throughout one's lifetime, he said. But this basic maintenance mechanism can get overwhelmed with serious disease or trauma. |
