Gil Lieberman wrote:
> Does anyone have information on this latest research?
> researchers at Mass General have succeeded in regrowing spinal cord nerves that had been severed...They have found a chemical switch that allows the nerves to regrow. If they can regrow people's own nerves then stem cell transplants will not be necessary and the ethical issues will become null...I'm not sure why the press hasn't picked it up.
Technique stirs hope for spinal cord injury treatment
NEW YORK, May 28, 1999 (Reuters Health) -- New research in rodents may
some day offer hope to the thousands of Americans paralyzed due to
spinal cord injuries.
In the May issue of the journal Neuron, two researchers from
Massachusetts General Hospital in Boston report on a new technique that
may stimulate the repair of severed nerves at the site of a spinal cord
injury. The successful reconnection of a severed spinal cord was
previously believed to be an unattainable goal.
But ``the question is no longer whether spinal cord regeneration is
possible but how it will be achieved,'' noted researcher Dr. Clifford
Woolf of Neural Plasticity Research Group at Massachusetts General
Hospital in a written statement.
In a complex set of experiments, the researchers were able to repair
spinal cord injuries in rats by tricking cells into growing beyond the
area of a spinal cord injury, he explained. ''While the particular
approach we used cannot be applied in humans, it points us in a
promising new direction,'' Woolf added.
There are an estimated 250,000 people with spinal cord injuries living
in the United States. On average, 11,000 new injuries are reported every
year, according to the American Paralysis Association. Loss of movement
and sensation in the lower body affects 55% of people with spinal cord
injuries and 44% cannot move their arms and legs.
Woolf and colleague Simona Neumann explained that nerve fibers in the
adult spinal cord cannot regenerate, but damaged nerves in the arms and
leg (peripheral nerves) can heal themselves. Yet both of these nerve
fibers come from the same types of cells, a fact that has frustrated
researchers for years.
Such sensory nerve cells (neurons) have two axons that extend from the
main part of the cell located next to the spinal cord. One axon (the
central branch) joins the spinal cord and travels to the brain, while
the other (peripheral) axon travels to the arms and legs. If the
peripheral branch is injured, it will regenerate, but the central branch
will not.
Other attempts to repair spinal cord injuries have focused on the
different environments surrounding the branches, but the new study took
a novel approach. The investigators sought to determine whether the cell
was receiving molecular signals from the injury site to stimulate
regeneration.
``Maybe damage to the central branch does not switch on these growth
signals, while damage to the peripheral branch does,'' they
hypothesized.
Woolf and Neumann tested this theory in rats. Injuring the peripheral
nerve and the spinal cord stimulated a complete regeneration across the
injury site. By comparison, damaging the spinal cord and not the
peripheral nerves resulted in no growth.
``We have shown that if we can switch these cells into a state where
they can grow, they will grow -- even the central branch,'' Woolf said.
``The problem was not that the adult central nervous system is hostile
territory for growth as previously thought. The problem is getting the
injured cells to grow,'' he added.
The next step is to identify the molecular signals that induce this
growth and the genes that they act on, Woolf explained.
``If we can find ways to turn those signals on without the peripheral
nerve injury and apply them soon after patients suffer spinal cord
injury, we may finally achieve what was once seen as an unreachable
goal: reconnection of a severed spinal cord,'' Woolf concluded.
SOURCE: Neuron 1999;22.
Copyright © 1999 Reuters Limited.
--
Judith Richards, London, Ontario, Canada
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