Aurele Vautour is tired of waiting.
Not only does he have the terrible weight of waiting for
his father, 94-year-old Ovide, to die, he's also waiting
to find out if he too will end up with the debilitating
Alzheimer's disease (AD) that's ruined Ovide's life. But
what if Mr Vautour didn't have to wait any longer? What
if he could get a scan now, at 57, to find out if yet
another Vautour will be struck down?
PITTSBURGH
DISCOVERY
Early diagnosis could soon be a reality thanks to the
recent discovery of a compound that can identify the
presence of amyloid plaques and tau proteins of AD years
before any symptoms appear. One of the discoverers of
the compound, Dr William E Klunk of University of Pittsburgh's
School of Medicine, was presented with an award for
his work at the International Conference on Alzheimer's
Disease and Related Disorders in Philadelphia.
The combined American and Swedish
team described how the compound, dubbed Pittsburgh compound-B
(PIB), glues itself onto amyloid plaques in the brains
of living AD patients in an article in March's Annals
of Neurology. The compound quickly zeroes in on
the amyloid plaques which are then detected by positron
emission tomography (PET) scan.
Meanwhile the research has been
progressing. At the conference, Dr Klunk and his colleagues
shared some of their latest research, presenting PET
scan data from a study involving five patients, this
time with mild cognitive impairment (MCI) rather than
diagnosed AD. They found that some of the MCI patients
had the same levels of amyloid deposition as normal
controls, while others had amyloid deposition levels
indistinguishable from AD patients. Did that mean they'd
go on to develop AD? We still don't know. But Dr Klunk
did offer this prediction at the conference: "Amyloid
imaging with PET may become useful for predicting which
people with MCI will progress to Alzheimer's in the
near future."
AIDING
AD RESEARCH
In an interview with NRM, Dr Klunk ponders the
wider impact of the discovery. "The real value in the
PIB test right now is its usefulness for speeding up
research," he says. "Since it's so sensitive, it will
allow researchers to look at how AD begins, how it progresses
and how effective new drugs are at slowing down or reversing
the disease."
Dr Klunk notes that though it's
already possible to diagnose early stage AD at about
an 85 to 95% accuracy simply using neuropsychological
exams, PIB has time on its side. "It can identify patients
at high risk of early onset AD as much as a decade before
symptoms show up. Once treatments to prevent amyloid
deposition become available, early detection will be
critical," he adds.
Neurologists working on the
frontlines are just as enthusiastic about PIB's diagnostic
possibilities. "PIB is the most exciting imaging finding
of the year for AD, and will probably replace diagnostic
MRI in clinical trials," says Montreal neurologist Dr
Serge Gauthier.
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