Stroke
Despite decades of study, there are few treatments for this devastating disease. Alberta researchers are studying stroke from many angles to improve stroke prevention, develop better treatments, and enhance recovery.
Story by Connie Bryson/Illustrations by Hugo Dubon
Stroke recovery
It is certainly not the way Dr. Bryan Kolb would have wanted it. But 25 years ago, in the midst of a successful career as a neuroscientist studying stroke, Dr. Kolb woke up unable to see the left side of his world. He had suffered a stroke. While the symptoms eventually improved, a blind spot in his vision is a constant reminder of the trauma in his brain. The experience changed many things about Dr. Kolb's life, including his approach to his research.
"Up until I had my stroke, I was interested in how the cerebral cortex (the part of the brain that controls thought, reasoning, memory, sensation, and movement) works and how stroke affects that," he explains. "I had never really thought about recovery from stroke. As soon as I needed treatment, I quickly realized that there wasn't anything available. That got me thinking about how researchers like myself should look at the ways we can make things better for patients."
At the time of Dr. Kolb's stroke, scientists were just beginning to understand the concept of plasticity in the brain, which is the ability of the brain to reorganize neural pathways based on new experiences. Without plasticity, we would never be able to learn. Dr. Kolb saw plasticity as key to better recovery and improvement after stroke.
His research focuses on how neurons (nerve cells) in the cerebral cortex reorganize in response to injury, such as stroke. In particular, Dr. Kolb studies how these changes affect behaviour, a scientific discipline known as behavioural neuroscience. The University of Lethbridge's Canadian Centre for Behavioural Neuroscience, where Dr. Kolb is based, is internationally recognized for research in this field.
Dr. Kolb studies recovery from stroke in rats. He compares various treatments to a treatment called complex housing—the very best treatment for stroke in rats. Complex housing involves placing the animals in an enriched environment that changes frequently and features a lot of toys and social interaction. "It is most effective to have rats in these complex environments 24/7," explains Dr. Kolb. "The equivalent in humans would probably be intensive multidisciplinary therapy for many hours a day with physical therapists, occupational therapists, and psychologists. This is obviously impractical. The question becomes what can we do that gets us close to the outcomes we get with intensive therapy?"
Dr. Kolb's team has shown that nicotine is very effective at stimulating the growth of new connections between neurons. A range of studies in infant and adult rats has shown that, as long as the strokes aren't too big, nicotine (which is administered by injection) will improve outcomes. Results are even better if nicotine is combined with complex housing. Working with Dr. Sam Weiss (who receives support from Alberta Innovates – Health Solutions) at the University of Calgary, Dr. Kolb has also had success using neural stem cells for stroke treatment in rats.
In recent years, Dr. Kolb has pushed his team to go beyond demonstrating behavioural changes to gaining a scientific understanding of why behaviour changes. This has led to a focus on genetics in his lab. For example, by determining how complex housing affects genes, it might be possible to figure out why the treatment works so well. Knowing what genes are turned on and off could be the basis of powerful treatments that target these genes.
"A colleague of mine has estimated that it takes about 30 to 40 years for a discovery in stroke research to translate into something useful for patients,” says Dr. Kolb. “I believe that what’s slowing things down is the lack of a scientific basis for stroke treatment, and as a result we don’t understand why treatments work or why they don’t work. This is unacceptable for such a devastating disease."