Scientists have used embryonic stem
cells to restore function in the legs of paralyzed mice, raising
hopes they may some day achieve the same result in humans.
In the study, stem cells taken from mouse embryos were
chemically transformed in a lab into motor neurons, cells that
carry impulses from the brain and spinal cord to receptors in
the muscles. Researchers then injected the neurons into the mice
in such a way that three in every four animals were able to bear
weight on their hind legs and take steps after six months.
``This work is a remarkable advance that can help us
understand how stem cells might be used to treat injuries and
disease and begin to fulfill their great promise,'' said Elias .
Zerhouni, Director of the National Institutes of Health, in a
statement. ``The successful demonstration of functional
restoration is proof of the principle.''
The study, to be published in the Annals of Neurology next
week, was funded in part by the NIH. It suggests similar
techniques may eventually be useful for treating such disorders
as spinal cord injury and Lou Gehrig's Disease, also known as
ALS, both of which leave people unable to use their limbs, the
researchers said. They cautioned that such an advance in humans
remains many years away.
The research used a cocktail of chemicals that help build
nerves while inhibiting the body's ability to protect itself
from the new cells. The cocktail allows the motor neurons to re-
connect, essentially re-establishing the circuitry that allows
the body to signal muscles that they're needed.
``This study provides a 'recipe' for using stem cells to
reconnect the nervous system,'' said study leader Douglas Kerr,
of the Johns Hopkins University School of Medicine in Baltimore,
Maryland, in a statement today. ``It raises the notion that we
can eventually achieve this in humans, although we have a long
way to go.''
