Currently, there are drugs that treat the symptoms of medical conditions associated with Down syndrome but nothing to improve brain function.
But in 2007 Costa demonstrated that memantine could improve memory in mice with Down syndrome. He then set out to replicate those findings in a human trial of the drug.
"This is an excellent example of translational science," he said. "We took a drug that worked well in mice and we tested it in humans with positive results."
Although the trial was small, the results could have far-reaching implications. Costa said a follow-up study was needed using a larger group of people with Down syndrome. Another important step will be to pursue studies with younger, school-age participants with Down syndrome. They would have more rapidly developing brains and, since they are in school, would be routinely tested so the effects of the drug could be closely monitored. That could take as little as five years.
Researchers also want to know if memantine can ward off the onset of Alzheimer's disease in those with Down syndrome. The two conditions show striking similarities and researchers are actively exploring how they may be linked. Babies born with Down syndrome, for example, often carry the biological markers for Alzheimer's disease.
"Everyone with Down syndrome will develop Alzheimer's disease pathology by their mid-30s," Costa said. "We would like to know if this drug can slow down or even halt the development of that disease in adults with Down syndrome."
Memantine works by normalizing the function of a glutamate receptor in the brain known as the N-methyl-D-aspartate or the NMDA receptor.
"This receptor plays a central role in memory and learning," Costa said.
Given the small size of the study and the need for more research, Costa stressed that people should not start taking memantine for Down syndrome. Although it has proven safe and well-tolerated by the study participants, researchers urge caution
|Contact: Jacque Montgomery|
University of Colorado Denver