Stem cells aid spinal cord injured-mice

By Will Boggs, MD

NEW YORK (Reuters Health) – Human neural stem cells can
replace damaged cells and improve function in a mouse model of
spinal cord injury, according to a report released Monday.

For treating spinal cord injury, “there is hope, but we are
a long way off,” Dr. Brian J. Cummings from University of
California, Irvine, told Reuters Health. “Our study improved
function in mice with very controlled injuries. We did not cure
these mice.”

Cummings and colleagues injected human neural stem cells
into the site of spinal cord contusion injury in mice and
followed their progress.

The human cells survived and engrafted extensively within
the injured mouse spinal cord, the authors report, with cells
persisting 17 weeks after transplantation.

Injected neural stem cells differentiated into neurons and
formed synapses — connections between neurons, the researchers
note.

Mice injected with human neural stem cells showed evidence
of recovering coordinated locomotor function and stepping
ability 16 weeks after engraftment, the report indicates.

“To our knowledge,” the investigators write, “this is the
longest time that mice receiving stem cell grafts of any type
have been tracked behaviorally.”

Treatment of mice with toxin targeting the human cells
resulted in decreased locomotor function, the results indicate.
“This suggests that at least some of the recovery was the
result of integration between the grafted cells and the host
cells,” Cummings said.

Summing up, Cummings said future treatments for spinal cord
injury will likely involve a combination of therapies noting
that “spinal cord injury is a very complex syndrome, and no one
treatment will solve the entire problem.”

SOURCE: PNAS Early Online Edition, September 19, 2005.