Amplifying The Fight Against ALS

Main Category: Muscular Dystrophy / ALS
Article Date: 19 Jun 2008 - 3:00 PDT

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Your ability to walk, swallow food and even breath depends on your brain's ability to talk to your muscles. Any interruption in this vital conversation is a major threat to your health. A recent discovery by Dr. Robert Brownstone, a neurosurgeon and researcher at Dalhousie University, may help keep the conversation going in people with amyotrophic lateral sclerosis (ALS).

ALS, also known as Lou Gehrig's disease, is a devastating, progressive illness that results in paralysis and, ultimately, death. It attacks motor neurons, the nerve cells that receive signals from your brain and tell your muscles to move. However, not all movement commands come directly from the brain.

"When you are walking, your brain has way too much to do to be constantly telling your muscles to contract," explains Brownstone. "So your brain sends a message to your spinal cord to start walking, and your spinal cord then produces the pattern of walking."

There are special nerve cells called interneurons within your spinal cord that help coordinate these muscle movements. Last year, Brownstone and his team discovered a specific class of interneurons that play an important supporting role in helping you move.

"These interneurons change the responsiveness of motor neurons to signals from the brain and spinal cord," says Brownstone. "In other words, they act like an amplifier, so that the motor neurons need less input to produce the same output."

This system of special neurons could hold tremendous potential for treating people with spinal cord injuries and diseases such as ALS. Brownstone and his colleagues at the Brain Repair Centre (BRC) in Halifax are working to improve our understanding of what these interneurons do and how they could be targeted for treatment.

For example, spinal cord injury treatment strategies usually focus on repairing or regenerating injured pathways in the spine. But even if researchers can figure out how to regenerate spinal pathways, the treatment will only be successful if the right spinal cord neurons can receive signals from the brain, process these signals, and transmit them to motor neurons. Understanding how interneurons are involved in this communication process is essential.

Brownstone thinks this class of interneurons may also play an important role in the development of ALS. A previous study suggested that these amplifying nerve cells start to degenerate in people with the disease. With funding from the Canadian Institutes of Health Research and Project ALS, Brownstone is investigating the possibility that the breakdown of interneurons leads to the motor neuron death that characterizes ALS.

"At this point it's kind of a new, crazy idea, but we feel it warrants study," says Brownstone. "Our next step will be to determine how the brain controls interneurons and how they malfunction in diseases such as ALS."

Source:
David Coulombe
Canadian Institutes of Health Research (CIHR)
www.irsc-cihr.gc.ca