TRIALS have started in Britain of a vaccine to combat Alzheimer's
disease
after encouraging results of animal and human tests.
The most common mind-robbing disease affects one in 10 of those aged
over 65
and nearly a quarter of those over 85, causing bouts of dementia, loss
of
memory, wrenching personality changes and, eventually, death.

About 80 patients are enrolled in the vaccine study in which they are
being
checked for signs that the vaccine has stimulated a response strong
enough to
fight the disease, which is becoming more prevalent as the average age
of the
population increases.

The experimental vaccine, developed by Elan Pharmaceuticals in Dublin,
raised
tremendous excitement last year when the company discovered that in
mice it
could reduce the brain-clogging plaques that are the hallmark of the
disease.

The main ingredient of the plaques is a fragment of a protein called
beta
amyloid. Elan is testing the idea that a vaccine made from beta
amyloid would
stimulate the immune system, notably microglial cells, the brain's
"garbage
men", to eradicate the plaques.

Prof Richard Morris of Edinburgh University told the British
Association
science festival in London that the British study had shown that the
vaccine
was safe, paving the way to bigger studies that would test whether it
might
be able to slow the progression of mild to moderate Alzheimer's
disease.

Prof Morris said: "It has passed the first phase of safety testing. It
is
phenomenally exciting. This is the first time in 30 years of research
that we
have something that, rather than deal with the symptoms, is stemming
the
underlying cause of the disease."

However, key animal trials being conducted to investigate the vaccine
further, notably to reveal its underlying mechanism, have fallen
behind rival
research in America as a result of the bureaucracy that regulates
animal
experiments.

A new animal test devised by Prof Morris and his team holds the key to
establishing unequivocally whether the experimental vaccine can
prevent
memory loss as well as halt the advance of the disease by revealing
what is
happening at the molecular level. He said: "That is important. It
could be
that clearing the plaques does nothing to improve memory. We need to
find
out."

Because of the delay over the British studies, being conducted by Prof
Morris
and colleagues at Elan in San Francisco, a group based in Florida and
a
second in Toronto have already reported preliminary results in July
that
suggest that a similar vaccine can indeed prevent memory loss.

In the Toronto study, vaccinated Alzheimer's mice learned how to get
through
a maze test quicker than unvaccinated mice, offering promising
evidence that
the vaccine may affect symptoms as well as the plaques.

The British Association's annual meeting is associated with the
Creating
Sparks science and arts festival.