Tests with mice suggest potential avenue for improving mental functioning, researchers say
FRIDAY, June 4 (HealthDay News) -- Researchers say they improved the learning capacity of mice afflicted with a disease similar to Down syndrome by interfering with the production of a specific protein.
The "beta-amyloid" protein is found in mice and people, the study authors noted, and is thought to play a role in the cognitive decline associated with Alzheimer's and Down syndrome.
The study, reported online June 3 in the journal PLoS One, was conducted using 4-month-old mice that had a genetic anomaly that caused them to display learning disabilities similar to those in children with Down syndrome.
This preliminary study raises the intriguing possibility that drugs that lower beta-amyloid levels might offer some benefit to children with Down syndrome, study co-author Dr. Craig Powell, an assistant professor of neurology at UT Southwestern Medical Center in Dallas, said in a news release.
The authors point out that Down syndrome is a genetic disease caused by the presence of an extra copy of chromosome 21, which leads to the above-normal production of beta-amyloid.
With that in mind, Powell and his colleagues treated young mice with the experimental drug DAPT, which blocks beta-amyloid production by targeting a key enzyme, gamma-secretase.
After four days of treatment, the mice experienced a 40 percent drop in beta-amyloid levels. In turn, maze navigation tests revealed an improvement in their ability to learn tasks, so that eventually their performance was deemed as good as that of mice with no genetic impairment.
The researchers cautioned, however, that for the time-being this particular approach is a blunt instrument that blocks not only the targeted enzyme's ability to spark beta-amyloid production but also a host of other critical tasks the enzyme performs, many of which are central to proper brain function.
The team plans to seek out other drugs that might knock out only beta-amyloid production, while leaving the enyzme's other functions intact.
For more on Down syndrome, visit the National Down Syndrome Society.
SOURCE: UT Southwestern Medical Center, June 3, 2010, news release
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