Alzheimer's find may allow early treatment
Warning sign discovered in mice

Chad Skelton
CanWest News Service

Thursday, March 04, 2004

Scientists at the University of B.C. have discovered what may be an early
warning sign of Alzheimer's disease that could allow doctors to treat patients
decades sooner than was possible before.
Researchers have discovered that mice genetically modified to develop an
Alzheimer's-like disease exhibit noticeable gaps in their {*filter*}-brain barrier
long
before they develop the plaques on the brain that are hallmarks of the
disease.
Wilfred Jefferies, the principal researcher behind the study, cautioned the
tests have not yet been replicated in humans. "If it is applicable in humans,
it could be used as an early-warning sign," he said, adding it could lead the
way to new methods of treating Alzheimer's disease in its early stages.
One of the things that makes the research so interesting is the breakdown in
the {*filter*}-brain barrier took place in the mice very early in the development
of the disease.
The equivalent in humans, Jefferies said, would be the early 20s.
"We were surprised in the animal model that this feature exhibited so early
in the disease," Jefferies said.
The delay between the breakdown of that barrier, and the development of brain
plaques, took about six months in the mice, Jefferies said -- the equivalent
of several decades in humans.
Amyloid plaques are one of the two brain abnormalities that define
Alzheimer's disease. The other is neurofibrillary tangles.
Amyloid plaques are sticky buildup that accumulates outside nerve cells, or
neurons. Amyloid is a protein normally found throughout the body. For unknown
reasons, in Alzheimer's disease, the protein divides improperly, creating a
form called beta amyloid that is toxic to neurons in the brain.
Technically, an individual may display all the behavioural and cognitive
symptoms of Alzheimer's, but, if the brain does not contain the hallmark
plaques
and tangles, there is no diagnosis of Alzheimer's. The appearance of amyloid
plaques in the brain can precede the behavioural symptoms by years.
Jefferies, a professor at UBC's Biomedical Research Centre, said he is
working on a study of humans to determine if similar {*filter*}-brain-barrier
breakdowns
exist.
He said he will also begin research to see if treatments can be found that
would repair the barrier. "We're looking at how we can correct this breach in
the {*filter*}-brain barrier," Jefferies said.
The {*filter*}-brain barrier is a largely impermeable layer of cells that
surrounds the brain, protecting it from the diseases and bacteria that afflict
the
rest of the body.
Protecting the brain from disease is important because brain cells do not
regenerate themselves as quickly as other human tissue.
? The Calgary Herald 2004