Dr. Albert Aguayo


Doing the "impossible"

SYLVAIN COMEAU | It's been an up and down couple of years for neurology professor Albert Aguayo.

Two years ago, the Canadian Neuroscience Network, a national network of centres of excellence that united neuroscientists from academia and industry across the country, lost its federal funding.

The decision stunned Aguayo, the network's scientific director, because the network had just earned glowing marks from a team of outside scientists who scrutinized the network for the federal government. The Network has been replaced by the Canadian Neuroscience Partnership, which is being sustained by industry links and various individual grants.

More recently, Aguayo was one of a handful of leading Canadian neuroscientists profiled in The Toronto Star. Aguayo and his colleagues were singled out as "true heroes of our society, people who live for figuring out what makes our bodies work and how to help us when our bodies stop working," by the newspaper.

This summer, Aguayo learned that he had won the $50,000 Killam Prize for Health Sciences from the Canada Council, one of the country's most prestigious prizes for scientists.

The Killam Prize is awarded annually "in recognition of distinguished lifetime achievement and outstanding contribution to the advancement of knowledge in the fields of natural sciences, health sciences and engineering."

Aguayo, the director of McGill's Centre for Research in Neuroscience at the Montreal General Hospital Research Institute, is a pioneer in the regeneration of damaged or diseased nerve cells, a goal which was viewed, until recently, as impossible.

The council cited Aguayo's success in challenging the conventional wisdom in the field. "Dr. Aguayo is known internationally for the ground breaking studies that he and his colleagues carried out at McGill showing, for the first time, that nerve cells in the brain and spinal cord of adult animals retain the ability to regrow and make new functional connections after injury.

"This work is revolutionary because it not only demonstrated the existence of a neuronal potential for repair, but also because it showed that neural regeneration could be enhanced by changes in the environment of the damaged nerve fibres."

In an interview, Aguayo says that his current research is focused on the regeneration of damaged nerve fibres in the eye. His work on rats has shown promising recent results.

"For the past 10 years, we have been working on the retina -- the projection of nerve fibres from the eye to the brain -- of rats. We're focusing on the eye because those nerve cells are much more accessible, and because the retina is the site of serious medical problems leading to blindness."

His team has produced recent breakthoughs.

"We have shown that the majority of the nerve cells in the retina, when damaged, could regrow. They can regrow for distances that are three or four times longer than the distance required for nerve fibres to reach their target in the brain. We exaggerated the course that nerve cells need to reach into the brain, in order to stress the tremendous ability of adult nerve cells to regrow."

The team has focused their attention on molecules known as growth factors, which are produced in abundance in the peripheral nervous system (the nerves in the limbs) by Schwann cells.

"Growth factors do not seem to be produced in sufficient quantities in the central nervous system. So we introduce genes into the eye which stimulate cells in the brain to produce growth factor molecules, in a sustained and abundant way. Essentially, we have converted certain nerve cells into growth factor producing cells, whereas they normally do not exist in the brain, spinal cord and the eye."

Experiments on blind rats have shown that the retina can regrow and find the natural neural pathways into the brain.

"The distance separating the eye from the part of the brain that processes visual information for the animal is about nine millimetres. We can get those nerve cells to regrow, over a conduit or bridge that we create -- out of the eye, over the skull, under the scalp, and then into the part of the brain to make the proper neuronal connections.

"Then, when you shine a light into the eye of the animal, the impulse will travel all the way, and activate nerve cells in that part of the brain."

But does that mean that the animal actually sees?

"We can't ask the rat if it sees the light, but we know that the light has an effect on the behaviour of the animal."

Aguayo refuses to speculate on what therapies could result from this research, saying that such projections could raise false hopes, but says that the most important result so far is that "we're beginning to understand the determinants of regrowth and repair in the brain, and the implications of these discoveries are enormous. However, we don't know what applications might result. We're not at that stage yet."

Besides heading his research team, Aguayo has also served as president of the Canadian Association of Neuroscience, the Canadian Neurological Society and the Washington-based Society for Neuroscience.