Advances
Against Alzheimer's Slow But Steady
November Is National
Alzheimer's Disease Awareness Month
The fight against
Alzheimer's disease has been marked by a recent series of encouraging
advances, experts report.
The latest of these
small steps came recently when a US Food and Drug Administration
(FDA) advisory committee recommended approval of the medication
memantine, which experts say seems to slow the progression of
moderate and severe Alzheimer's.
Some 4.5 million US
adults have Alzheimer's disease, which primarily affects older
people and is characterized by the progressive loss of memory
and other cognitive skills. An estimated 11.3 million to 16
million seniors are likely to have the disease by 2050, the
Alzheimer's Association predicts.
According to these
latest estimates of the current and future prevalence of AD,
reported by Dr. Denis A. Evans, and colleagues of Rush-Presbyterian-St.
Luke's Medical Center in Chicago, the most notable increases
will be among people age 85 and older, when by mid-century 8
million people in that age group may have the disease.
November is recognized
as National Alzheimer's Disease Awareness Month.
Currently, memantine
is approved and being used to treat patients in Europe under
the name Axura®. If memantine is approved in the US, it
would be called the first medication in use for later-stage
Alzheimer's. A decision is expected by the end of the year.
There are few medications
on the market geared specifically for Alzheimer's and they have
only limited effectiveness. Memantine provides a ray of hope
because it has a different mechanism of action: it blocks the
overproduction of a brain chemical called glutamate.
Alzheimer's
a Major Problem, and Growing
The current mainstays
of Alzheimer treatment, called cholinesterase inhibitors, work
by boosting levels of another brain chemical, acetylcholine.
Cholinesterase inhibitors are approved for use against mild
and moderate forms of the disease.
"It's always exciting
when you find something that works in a different way because
it suggests that people for whom one drug doesn't work, another
one may," says William Thies, vice president of medical and
scientific affairs for the Alzheimer's Association.
"It also opens up
the possibility that the medications can be used together,"
Thies says.
Dr. Marshall Keilson,
co-director of the Memory Disorders Program at Maimonides Medical
Center in New York City, says, "We're excited because it [memantine]
represents a new approach. It's the beginning of a new category
of treatments of Alzheimer's.
"It's not a miracle
drug, and it's by no means a cure," adds Dr. Keilson, "but it's
a fresh view of treating patients with Alzheimer's."
Medications
Geared Toward Symptoms
None of the available
or soon-to-be-available medications for Alzheimer's attack the
underlying cause of the disease, only the symptoms. That is
because researchers do not know the exact cause or causes
of the disease.
The approved cholinesterase
inhibitors elevate the levels of acetylcholine. But, Dr. Keilson
points out, "since the role of this chemical in producing Alzheimer's
is uncertain and may be late in the course of the pathology,
there's a certain limitation to what the medications can do."
They have been shown
to slow progression of the disease in a certain percentage of
patients. And some people were able to resume watching television,
reading a newspaper or carrying on a conversation, he says.
Research currently
is being conducted to see if medications that have been
approved for other conditions might be able to prevent or treat
Alzheimer's patients. They include nonsteroidal anti-inflammatory
drugs or cholesterol-lowering statins, but the jury is still
out on these medications.
On other fronts, certain
drugs are being developed specifically for Alzheimer's.
"If there's one thing
that is different today about Alzheimer's research than 20 years
ago is that we've got this huge wealth of basic information
about how the disease develops and what the fundamental biochemistry
is," Thies says. "All of that information gives us an opportunity
to intervene."
Scientists do not
yet know where to intervene but they are hot on the trail. One
of the main areas of research has been into strategies to limit
the production of amyloid, a protein that collects in the brains
of patients with Alzheimer's.
An experimental human
vaccine apparently succeeded in eliminating some of these protein
clusters, but may also have caused meningoencephalitis - or
swelling of the brain. The trial was halted last year but data
is still being gathered and there is talk that the vaccine has
been modified and may be tried again.
Other studies are
looking at compounds that would affect different enzymes implicated
in the protein buildup in the brains of Alzheimer's patients.
Because many of the
risk factors for Alzheimer's are similar to those for heart
disease, there has been speculation on the role of diet in preventing
Alzheimer's. Although diet and nutrition is a notoriously difficult
area to study, "it is perfectly reasonable to say that there's
a lot of good reason to adopt a lifestyle that leads to healthy
aging," Thies says.
Always consult your
physician for more information.
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November 2003
Advances
Against Alzheimer's Slow But Steady
Alzheimer's
a Major Problem, and Growing
Medications
Geared Toward Symptoms
What
Is Alzheimer's Disease?
Online
Resources
What Is Alzheimer's
Disease?
According to the National
Institute of Neurological Disorders and Stroke (NINDS),
Alzheimer’s disease (AD) is a progressive, neurodegenerative
disease.
Age is the most important
risk factor for AD; the number of people with the disease doubles
every five years beyond age 65.
NINDS
states that three genes have been discovered that cause early
onset (familial) AD. Other genetic mutations that cause excessive
accumulation of amyloid protein are associated with age-related
(sporadic) AD.
Symptoms of AD include
memory loss, language deterioration, impaired ability to mentally
manipulate visual information, poor judgment, confusion, restlessness,
and mood swings.
Eventually AD destroys
cognition, personality, and the ability to function. The early
symptoms of AD, which include forgetfulness and loss of concentration,
are often missed because they resemble natural signs of aging.
Presently, there is
no cure for AD.
For some people in
the early or middle stages of AD, medication such as tacrine
(Cognex®) may alleviate some cognitive symptoms. Donepezil
(Aricept®), rivastigmine (Exelon®), and galantamine
(Reminyl®) may keep some symptoms from becoming worse for
a limited time.
Also, some medications
may help control behavioral symptoms such as sleeplessness,
agitation, wandering, anxiety, and depression.
NINDS
is conducting and supporting research on neurodegenerative and
dementing disorders, including AD.
Scientists are currently
studying or testing different types of medications and
other substances to determine if they can stop AD progression.
These include nonsteroidal anti-inflammatory drugs (NSAIDS),
statins (such as those used for lowering cholesterol), folic
acid, gingko biloba, and vitamins E, B6, and B12.
Studies in basic science
are also exploring the potential of vaccines. The National
Institute on Aging and the National Institute
of Mental Health also support research related to AD.
Always consult your physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
Alzheimer's
Association
Alzheimer's
Disease Education & Referral Center
Centers
for Disease Control and Prevention (CDC)
National
Institutes of Health (NIH)
National
Institute of Neurological Disorders and Stroke
US
Department of Heath and Human Services
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