WASHINGTON: A new study has identified key elements that may make the
regeneration of nerve cells using the body's own stem cells following spinal
cord injury a possibility.
The seminal study, co-lead by Dr Philip Horner, neuroscientist at the University
of Washington, Dr Tim Kennedy, neuroscientist at the Montreal Neurological
Institute of McGill University, might help in providing novel therapies for
repairing previously irreversible nerve damage in the injured spinal cord.
In the study, the researchers tested numerous proteins and identified netrin-1
as the key molecule responsible for the migratory pattern of stem cells
following injury. "Because of their regenerative role, it is crucial to
understand the movements of stem cells following brain or spinal cord injury,"
Horner said.
"We know that stem cells are present within the spinal cord, but it was not
known why they could not function to repair the damage. Surprisingly, we
discovered that they actually migrate away from the lesion and the question
became why — what signal is telling the stem cells to move," he said.
In the developing nervous system, netrin-1 acts as a repulsive or attractive
signal, guiding nerve cells to their proper targets.
The team found that in the adult spinal cord, netrin-1 specifically repelled
stem cells away from the injury site, thereby preventing stem cells from
replenishing nerve cells. Very little knowledge is known as to why a wound to
the skin repairs itself but the adult nervous system is unable to repair itself
following spinal injury. This is in contrast to the developing brain and
non-mammals, which can repair, and regenerate after severe injuries.
The sole clue from these systems has been the role of stem cells and their
potential to develop into different cell types.
