http://www.sciencedaily.com/releases/2001/08/010817081453.htm
Source: Weizmann Institute
(http://www.weizmann.ac.il/)
New York, NY, August 17, 2001 --
Weizmann Institute scientists have proposed an innovative approach for
preventing complete paralysis after partial spinal cord injury. The approach
consists of boosting the body's natural immune mechanisms to improve the
outcome of trauma.
The team of Prof. Michal Schwartz
of the Weizmann Institute's Neurobiology Department has in the past already
developed one immune-based therapy for the spinal cord, currently being
tested in humans by Proneuron Biotechnologies Ltd. That therapy is aimed
at repairing the spinal cord after a complete injury. The new approach
pursues a related but different therapeutic target: to limit degeneration
after a partial spinal cord injury. The scientists report their latest
results in the August 15 issue of the Journal of Clinical Investigation.
Following injury to the central nervous
system (brain or spinal cord), a wave of damage spreads from the injury
site over several days or weeks, killing nerve cells and fibers that survived
the initial trauma. This secondary degeneration can be even more destructive
than the initial damage. As a result, an injury that initially inflicted
only partial damage on the nerve tissue in the spinal cord may eventually
result in total paralysis.
In the United States alone, approximately
10,000 people sustain a spinal cord injury each year. More than half of
these injuries are classified as incomplete, or partial, meaning that some
nerve fibers survived the initial trauma. If the surviving tissue could
be protected against secondary degeneration, this would significantly improve
the final outcome.
In the past, Schwartz and colleagues
showed that autoimmune T cells -- the white blood cells of the immune system
that interact with the body's own tissues -- have a protective effect on
damaged tissue in the spinal cord, reducing secondary degeneration. This
protective response is the body's own way of minimizing the consequences
of trauma. However, the naturally occurring T-cell response is restricted
in its effectiveness.
In the new study, rats were vaccinated
soon after severe partial injury to the spinal cord with peptides, or protein
fragments, derived from the central nervous system. The peptides were selected
so that they would boost the natural protective mechanisms of the immune
system without triggering an autoimmune disease. Rats vaccinated with the
peptides showed significant recovery of movement.
Tissue analysis revealed that the
treated animals had substantially more healthy nerve fibers in the spinal
cord than the untreated rats, suggesting that the treatment protected the
animals from secondary degeneration. Results indicate that the therapeutic
window for T-cell-based treatment is at least one week after injury. This
approach may also prove effective in other disorders of the central nervous
system, such as stroke or traumatic brain injury.
Professor Schwartz's team included
Ehud Hauben, Eugenia Agranov, Amalia Gothilf, and Uri Nevo of the Weizmann
Institute, and Avi Cohen and Igor Smirnov of Proneuron Biotechnologies
Ltd. Her research is supported by Proneuron Biotechnologies Ltd., the Jerome
and Binnette Lipper Medal, the Daniel Heumann Fund for Spinal Cord Research
and in part by grants from the Glaucoma Research Foundation and the Alan
T. Brown Foundation to Cure Paralysis. Michal Schwartz holds the Maurice
and Ilse Katz Chair of Neuroimmunology.
The Weizmann Institute of Science,
in Rehovot, Israel, is one of the world’s foremost centers of scientific
research and graduate study. Its 2,500 scientists, students, technicians
and engineers pursue basic research in the quest for knowledge and to enhance
the quality of human life. New ways of fighting disease and hunger, protecting
the environment, and harnessing alternative sources of energy are high
priorities at Weizmann.
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Date: Posted 8/17/2001
http://www.sciencedaily.com/releases/2001/08/010817081453.htm