Q & A with Dr. Lorne Zinman, director of Sunnybrook’s ALS clinic, which is the largest of its kind in Canada. Dr. Zinman is also an associate professor at the University of Toronto and associate scientist in the Hurvitz Brain Sciences Research Program.
How is focused ultrasound used to open the blood-brain barrier in patients with ALS?
The blood-brain barrier (BBB) is different from other blood vessels in the body. For example, liver or kidney capillaries are porous, so molecules in the blood can exit.
Think of the BBB as a tight hose, which limits compounds from leaving in the bloodstream. It is an evolutionary protective mechanism that prevents drugs, toxins, or micro-organisms that can cause infections from leaking out and entering the brain and spinal cord. The problem is, it also prohibits us from getting therapeutics into the brain, and that’s why the technique of using low-intensity focused ultrasound to open the BBB is so revolutionary. It provides us with a temporary window whereby an experimental ALS therapeutic can enter the central nervous system and target the motor neurons that are degenerating.
By using low intensity focused ultrasound waves and microbubbles that are injected into the bloodstream, we are able to disrupt the BBB, and temporarily open it. As the research continues, we will be able to couple this novel BBB opening technique with the intravenous administration of our most promising ALS therapies.
Currently, we are investigating the safety and efficacy of opening the BBB over the motor cortex in patients with ALS which is a world first phase 1 trial.
What was it like to accomplish this world first?
Along with our outstanding fellow Dr. Agessandro Abrahao, it is exciting to be able to share our enthusiasm for this project with patients and discuss how the research is progressing. We take great pride in being a part of a world-class team of experts at Sunnybrook including Drs. Nir Lipsman, Kuellervo Hynynen, Isabelle Aubert, Carol Shuurmans and Sandra Black. They truly are a multidisciplinary all-star team.
It is inspiring for Agessandro and me to work with patients and families with ALS on a daily basis. We continue to be motivated by their bravery, intelligence and altruism. This phase I safety study includes no ALS therapeutic and there is potential risk, yet patients have eagerly volunteered to advance the science in an effort to help all patients with ALS.
Is focused ultrasound a game-changer?
It certainly could be in ALS. Before focused ultrasound (FUS), more invasive techniques to access the central nervous system such as surgery were used to access to the brain and spinal cord.
With FUS, we are investigating this as a non-invasive way of safely and temporarily opening the blood-brain barrier to access degenerating motor neuron in ALS.
It’s very exciting for our team to evaluate this innovative, cutting-edge technology in this untreatable neurodegenerative disease.
What does this mean for patients and their families?
Although this study represents a key first step, we are still in the earliest phase and we must prove that it is safe to open the blood-brain barrier over the motor cortex in patients with ALS.
If we can demonstrate safety and feasibility, we will have set the foundation to test a number of promising therapeutics targeting motor neurons in ALS. For now, it’s one step at a time, but with novel technologies like MRI-guided FUS, we think the future is much brighter for patients and families with ALS.
Phase 1 of this trial is open to Canadian residents and will involve eight patients with ALS who are 18 years and older. Patients cannot be taking anticoagulants and need to be able to tolerate lying flat in an MRI. Learn more about the trial and how to get involved »