t expected
to enhance nerve growth. Moreover, the researchers saw that
the new fibers were made by nerve cells residing in the
"We have established that the enzyme sialidase, which
destroys one of the molecules that inhibits nerve
regeneration, is sufficient to robustly improve nerve fiber
outgrowth from the spinal cord," Schnaar said.
Surgical transplantation of a peripheral nerve to help
nerve fiber growth from the spinal cord has shown limited
success in humans. Lynda Yang, the study's lead author and
an assistant professor of neurosurgery at the University of
Michigan, said, "The addition of a new treatment to enhance
our current surgical management of brachial plexus avulsion
in people would be welcomed by patients and surgeons
alike." Yang helped pioneer the study of ARIs in the 1990s
while a doctoral student with Schnaar at Johns Hopkins.
Having shown in this study that sialidase can increase
the number of spinal cord nerve cells that extend fibers
into a transplanted nerve, Yang now is testing to see if
the nerves re-establish muscle control. "We're very
interested in seeing how much function you can get back,"
According to Schnaar, there is some evidence that this
transplant technique coupled with sialidase treatment can
coax other, nearby nerve cells within the spinal cord to
grow out as well. "Once you rewire, then the brain does an
amazing job of sorting it all out," he said.
Having established the ability of sialidase to improve
spinal nerve regeneration into transplanted peripheral
nerves, Schnaar and his research team at Johns Hopkins are
testing the same treatment to see whether it will help
nerve regeneration in other types of spinal cord
"Even a small improvement might mean a lot," Schnaar
said. "People with spinal cord injuries generally are not
looking to play football but to regain basic functions. A
modest improvement in nerve regeneration might make a big
improvement in a patient's quality of life."
The researchers were funded by two branches of the
National Institutes of Health: the National Institute of
Neurological Disorders and Stroke and the National Heart,
Lung and Blood Institute; and by the Department of
Neurosurgery at the University of Michigan.
In addition to Yang and Schnaar, authors on the paper
are Ileana Lorenzini, Katarina Vajn, Andrea Mountney and
Lawrence Schramm, all of Johns Hopkins.