|
|
Ed Note: The following is a press release from the University of
California, San Diego.
July 13, 2004 -- Using a combination of therapies and cell grafts, a team of
University of California, San Diego (UCSD) School of Medicine researchers
has promoted significant regeneration of nerve cells in rats with spinal
cord injury.
The therapeutic approach successfully stimulated new nerve fibers
called axons to grow and extend well beyond the site of the injury into
surrounding tissue, following surgically induced spinal cord damage.
These results prove that combinational therapy can promote the vigorous
growth of new axons even after a complete lesion of the spinal cord cells,
with the new growth extending through implanted tissue grafts, and into
the spinal cord and healthy tissue surrounding the injury site, according
to Mark Tuszynski, M.D., Ph.D., professor of neurosciences at UCSD and
senior author of the study. The paper is published in the July 14 issue of
the Journal of Neurosciences.
“Previous studies have demonstrated reduced lesion and scarring, tissue
sparing and functional recovery after acute spinal cord injury,” said
Tuszynski, who also has an appointment with the Veterans Affairs Medical
Center, San Diego. “This study shows unequivocally that axons can be
stimulated to regenerate into a cell graft placed in a lesion site, and
out again, into the spinal cord -- the potential basis for putting
together a practical therapy.”
The successful regeneration followed complete lesion of the nerve site.
The study, which targeted sensory axons, was not designed to test
functional improvement.
Axon regeneration is one of the many challenges confronting spinal cord
researchers. The axon is a critical communication path from the nerve
cell, with many sensory axons extending from the spine to the brain. When
the spine is severely damaged that connection is lost, and gaps form in
the healed spine that fill with fluid, an environment that complicates
regeneration efforts since axons can’t grow across the lesion cavity.
Therefore, to be successful, regeneration therapy must stimulate growth
and provide a scaffold that creates an appropriate environment to support
axonal growth.
The most dramatic axonal growth seen in the UCSD study was in rats
pre-treated with cyclic AMP (cAMP). The team injected cAMP, an important
cellular messenger that regulates various metabolic processes, directly
into the nerve cell nucleus before creating the lesions. After surgical
severance of the spine, the injury site was implanted with a tissue bridge
of bone marrow stromal cells and treated with neurotrophins (growth
factor). In these rats, over a three-month period significant growth of
axons was noted, extending into and beyond the tissue graft. Pre-treatment
with cAMP could be a practical approach for treating patients with
established, chronic spinal cord injuries, a possibility that is the
subject of current study by the UCSD group.
Co-authors of the paper are Paul Lu, Ph.D., UCSD Department of
Neurosciences; Leonard Jones Ph.D., UCSD Department of Neurosciences and
Veterans Affairs Medical Center, San Diego; and Marie T. Filbin, Ph.D.,
Biology Department, Hunter College, New York.
The research was supported by the National Institutes of Health, the
Veterans Administration, the Canadian Spinal Research Organization, and
the Swiss Institute for Research into Paraplegia.
Return To Table Of Contents |