Human stem cells help paralyzed rats, mice to walk
Johns Hopkins study could assist people, be a key to funding
Wednesday, July 25, 2001
By Michael Woods, Block News Alliance

BAR HARBOR, Maine -- Johns Hopkins University scientists
yesterday reported using human stem cells to restore the ability
to walk in rats and mice paralyzed by nerve damage like that
found in several human diseases.

"So far as we know, this is the first time human stem cells
have produced recovery from a disease in any animal, "
said head researcher, Dr. John P. Gearhart.

Gearhart, an internationally known stem cell authority,
said the achievement addresses one of the major objections
to federal funding for stem cell research.

Human embryonic stem cells are "building block" cells
that develop into every other kind of cell found in the body.
Researchers believe they can make replacements for body
tissue lost to disease or injury -- including whole new hearts,
kidneys and other organs for transplantation.

Nevertheless, the federal government has refused to fund
embryonic stem cell research because aborted fetuses are
a major source of the cells. They can be obtained in other ways,
one of which involves destroying human embryos stored
in fertility clinics.

The Hopkins research was done with stem cells obtained
from human fetuses aborted at 5-8 weeks of age.

One argument against federal funding, Gearhart noted,
is that human stem cells have not yet been shown effective
in treating a disease. The new findings weaken that argument,
he said.

"It's one thing to see evidence that stem cells work in laboratory
culture diseases, " Gearhart said at a renowned conference
on genetics, this year's being the 42nd Short Course in Medical
and Experimental Mammalian Genetics. "And it's quite another
to see actual function restored in an animal."

Videos showed the reversal of paralysis in the laboratory animals
to be dramatic. Researchers injected human neural stem cells
into the spinal fluid of about 80 rats and mice paralyzed by a virus
that attacks and destroys nerve cells that control
muscle movement.

Normally, animals infected with the Sindbis virus permanently
lose the ability to move their limbs, as neurons leading from
the spinal cord to muscles deteriorate. Animals drag limp legs
and feet behind them.

All of the animals treated with human embryonic stem cells
recovered the ability to walk, although not with a normal gait.

Researchers believe the cells may have reversed paralysis
in two ways. They may have grown into new rodent nerve
cells that replaced the cells killed by the Sindbis virus
or they may have produced chemicals that signaled the
rodent nerve cells to start growing.

Rodents infected with Sindbis virus are used as a model
for spinal motor atrophy. It is the most common inherited
neurological disease and the most common inherited cause
of infant death.

SMA affects as many as 1 in 6,000 infants, causing nerves
leading from the spinal cord to the muscles to deteriorate.
Children with SMA are born weak, have difficulty swallowing,
breathing and walking. Most die in infancy, although some
live into early childhood.

Gearhart said stem cell research may have its most immediate
application in treating SMA and a related condition, amyotrophic
lateral sclerosis, also called Lou Gehrig's disease.

ALS affects up to 20,000 adults, leading to whole-body paralysis
and death as motor nerves linking the brain, spinal cord and
muscles die.

Project ALS, a New York City organization that battles the
disease, funded the Hopkins research. The treatment could
be tested on humans within a few years, Gearhart said.

He predicted the ethical and religious concerns over stem cell
research will vanish as scientists discover ways of making
different kinds of cells without using embryos.
But he emphasized that federal funding of embryonic stem cell
 research is essential to developing those alternative techniques
 -- a step that could take 10 years with ample funding and longer
without it.

SOURCE: The Pittsburgh Post-Gazette
http://www.post-gazette.com/healthscience/20010725woodshealth3p3.asp

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