By Mari-Louise Rowley
Whenever we take a step, burn a finger, swat a fly or enjoy a cool breeze, peripheral nerves are involved. Without them, we would have no movement or feeling.
For people with peripheral nerve damage from injury or disease, repair strategies have not been very successful. When nerves have been severed, for example, often a nerve graft is needed to bridge the gap created. Though these nerves can regenerate, it is a slow, painful process that often leaves scarring and untreatable long-term damage.
University of Saskatchewan researcher Valerie Verge is part of a team of Canadian investigators, headed by University of Calgary (U of C) neurologist Dr. Doug Zochodne, who think they have found a way to improve nerve regeneration using electrical stimulation and computer chips.
“We have identified some of the key repair molecules and how to regulate them,” says Verge, a U of S professor of anatomy and cell biology and director of the Cameco MS Neuroscience Center. “We are close to knowing how to use computer chips to assist the process.”
The group was recently awarded $2.25 million from the Canadian Institutes of Health Research to design a conduit, or regeneration tube, in which miniaturized electronic chips will guide the regrowth of axons more accurately and swiftly than in normal healing. Axons are the long slender filaments at the end of nerve cells that transmit electrical impulses to the body.
If the team is able to develop an implantable device that can regenerate nerves, it could reduce pain and suffering for millions of people with peripheral nerve damage. Once developed, this research could potentially help patients with central nervous system damage and spinal cord injuries.
In collaboration with Tessa Gordon at the University of Alberta and Dr. Tom Brushart at Johns Hopkins, Verge and then graduate student Nicole Geremia played a key role in demonstrating that brief electrical stimulation of nerves greatly improves the regeneration of sensory neurons.
“Prof. Gordon works with the motor neurons that move your muscles, and we work with sensory neurons that register things like pain, temperature and the sensation of where your limbs are in space,” explains Verge.
The Verge lab has also been studying the protein BDNF, which nerve cells make in great quantity in response to stimulation such as exercise, seizures or in their nerve stimulation model. They found that this molecule is critical to turning on repair programs.
In carpal tunnel syndrome, a painful and increasingly prevalent condition, nerves are crushed rather than severed. In a preliminary clinical trial, team investigators Gordon and Dr. K. Ming Chan, also from the U of A, confirmed the benefits of electrical stimulation on people who have undergone carpal tunnel surgery.
These results, coupled with the discovery by U of C investigator Naweed Syed that snail neurons can grow on computer chips, led the group to believe that they could have the same success with a computer chip conduit when there is a need to bridge a nerve gap surgically.
Completing the team, Dr. Rajiv Midha, U of C head of neurosurgery, is working to develop artificial interfaces to bridge the gap in severed or crushed nerves, while U of C engineering professor Graham Jullien is designing the actual conduit.
Verge’s lab will assess the cellular and molecular responses to these nerve conduit prototypes in rodent models to make sure they work well before proceeding to human trials.
“It is really exciting to be working with so many exceptional colleagues,” says Prof. Verge. “We hope that down the road this research will not only help people with nerve injuries, but also degenerative diseases as well".