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.
More information
For more on Down syndrome, visit the
National Down Syndrome Society.