Karim Fouad and David Bennett
Spinal-cord injuries affect more than 41,000 Canadians, with 1,100 new injuries occurring each year.
But University of Alberta researchers have made an important discovery that could lead to more effective treatments for the thousands of people who live with
this type of injury
Karim Fouad and David Bennett, along with graduate student Katie Murray, all from the U of A�s Faculty of Rehabilitation Medicine, have identified one of the body�s natural self-repair mechanisms that kick in after injury.
�Our position is that you should find out what the natural recovery processes are and help them along,� said Bennett.
To better understand the discovery, the researchers say it is important to first understand the neurons in the spinal cord that control muscle contractions. These neurons represent a fairly autonomous part of the nervous system that control many basic functions such as walking and bladder control. These neurons are brought into a state of readiness by a transmitter called serotonin. Serotonin originates in the brain and projects down the spinal cord where it binds to serotonin receptors on the neurons.
�This process turns a quiet neuron into one that�s ready to respond to fast inputs from the brain,� said Fouad.
When someone suffers a spinal-cord injury they can lose almost all serotonin projections, so it was previously thought that the serotonin receptors were inactive. But this new discovery made by Fouad and Bennett shows that serotonin receptors are spontaneously active after spinal-cord injury, despite the absence of serotonin.
�This means there�s a massive self-repair in the response to a lack of serotonin,� said Bennett.
Their study shows that this receptor activity is an essential factor in the recovery of functions like walking.
�This is a major player in how the spinal cord responds and changes after injury. With this knowledge we can go ahead and design more meaningful treatments,� said Fouad. �For example, enhancing this receptor activity even further using pharmacologically or training might be a future approach to promoting locomotor recovery in patients.�
But, the researchers add, there is a dark side. While the serotonin receptors remain active after injury, they are permanently turned on. Fouad and Bennett say this activity is what contributes to muscle spasms, a common problem for people with severe spinal-cord injury.
The pair says the next step in helping patients with severe injury, who aren�t able to regain control of muscle contractions, is to examine how to block these serotonin receptors to stop the spasms from occurring.
Currently they are conducting a clinical trial looking at the antispastic action of drugs that block serotonin receptors. Those with spinal cord injury who are interested in learning more about participating in the trial can e-mail
Fouad and Bennett�s research
is funded by Alberta Innovates � Health Solutions, Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada and the National Institutes of Health and was published May 30, 2010, in the journal Nature Medicine.