Tuesday, March 14, 2006

Brain-Healing Nanotechnology

A ground-breaking treatment could restore lost abilities to stroke victims and others.

By Kevin Bullis

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Although victims of stroke and traumatic brain and spinal cord injuries sometimes recover through rehabilitation, they often have permanent disabilities, in part, because scar tissue and regulatory chemicals in the brain slow nerve growth, preventing nerve tissue from repairing itself. Now a treatment that has restored lost vision in lab animals appears to overcome these obstacles, allowing a mass of nerve cells to regrow after being cut.

"We think this is the basis of reconstructive brain surgery -- which is something nobody has ever heard of before," says Rutledge Ellis-Behnke, a researcher on the project and a brain and cognitive sciences researcher at MIT.

The treatment, described online this week in the Proceedings of the National Academy of Sciences and performed at MIT, Hong Kong University, and Fourth Military Medical University in China, may be available to humans in trials in as little as three years if all goes well in large-animal studies, the researchers say.

In their experiments, the researchers first cut into a brain structure that conveys signals for vision, causing the small lab animals to be blinded in one eye. They then injected a clear fluid containing chains of amino acids into the damaged area. Once in the environment of the brain, these chains, called peptides, bind to one another, assembling into nano-scale fibers that bridge the gap left by the damage. The mesh of fibers prevents scar tissue from forming and may also encourage cell growth (the researchers are still investigating the mechanisms involved).

As a result, nerve cells restored severed connections, allowing 75 percent of the animals to see well enough to detect and turn toward food. The treatment restored around 30,000 nerve connections, compared with 25-30 connections made possible in other experimental treatments, Ellis-Behnke says.

Because the treatment overcomes key obstacles to the healing of nerve tissue in stroke and traumatic brain and spinal cord injury, the researchers, as well as other experts in the field, believe it could prove to be an effective treatment for these types of nervous system damage.

"The presented data are almost too good to be true," says Wolfram Tetzlaff, professor and associate director of the International Collaboration on Repair Discoveries (ICORD) at the University of British Columbia. "Taken at face value, these findings are simply spectacular, and could become a very useful combination with other regeneration strategies," he says. "Future studies will show how these data will hold up." Such studies should be designed to determine whether the treatment works with a variety of brain injuries, not just the knife cuts studied so far, Tetzlaff says.

Brain-Healing Nanotechnology

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