Researchers Map Possible Brain Tumor Treatment
It forces molecules -- and perhaps someday drugs -- past blood barrier
FRIDAY, Oct. 4, 2002 (HealthDayNews) -- For children and some adults, a tumor in the brainstem can be a death sentence. Blood vessels protect the lower part of the brain, and doctors often can't breach them with drugs.
However, federal researchers think they've discovered a way to get medicines through the blood barrier and watch them do their work.
"The beauty of it is that you can watch what happens in real time as you treat the region. You can treat just enough, not too much or too little," says Dr. Russell Lonser, a neurosurgeon and researcher at the National Institute of Neurological Disorders and Stroke.
The brainstem is made up of several parts of the lower back of the brain, and it acts as both a control center and a relay station for body functions like movement, heartbeat, sight and the sense of touch.
About 10 percent of brain tumors among children appear in the brainstem, and 90 percent of those young patients die within 18 months of diagnosis, according to the National Cancer Institute. Adults are much less likely to get brainstem tumors than children, but they can still occur.
Doctors have trouble treating the tumors with chemotherapy because the brainstem is so inaccessible to drugs.
"The brain protects itself from toxic substances in the blood by a very tight cellular barrier between the blood vessel and the brain," says Dr. James Grisolia, a neurologist at Scripps Mercy Hospital in San Diego. "The cells have tight junctions that seal the brain more effectively than in other body organs."
Lonser and his colleagues sent so-called tracer molecules into the brainstem of monkeys and tracked them by using magnetic resonance imaging (MRI) technology. Their findings appear in the October issue of the Journal of Neurosurgery.
Researchers sent the molecules on their journey by using an 8-year-old technique that forces molecules through solid tissue. After the researchers injected the molecules into the brain, the tracking system found they spread throughout the brainstem.
The federal researchers are now testing drugs that could be administered through this technique.
Grisolia, who was not involved in the research, says the findings sound promising but are still very preliminary.
"They've only found a way using MRI to take pictures of where the drug is going, so we're still a long, long way from home," he says.
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