News reports of research into Alzheimer's disease Jan - June 2004
To search by subject, go to Alzheimer's subject index.
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There's a glossary of terms used in Alzheimer's research.
Disclaimer:
This section began as an offshoot of my
gathering of news items about memory. I am not a medical expert. My
background is in psychology. The information I have gathered here should
not be taken as providing any advice.
June
Doubt over effectiveness of cholinesterase inhibitors for treatment of Alzheimer's
A study involving 565 Alzheimer’s patients has found that while
donepezil did improve tests of mental and functional ability over the
first 2 years of treatment, the improvement was slight, and there was no
significant delay in institutionalization or progression of disability.
There were also no differences between donepezil and placebo in
behavioral and psychological symptoms, formal care costs, unpaid
caregiver time, adverse events or deaths, or between the two doses of
donepezil used in the study.
The study was reported in the 26 June issue of The
Lancet.
Full reference
http://www.eurekalert.org/pub_releases/2004-06/l-doe062304.htm
Why stroke and hypertension may increase risk of Alzheimer's
New findings of the presence of beta amyloid in the brain of a mouse
that overproduces a protein called p25 may help explain the occurrence
of sporadic Alzheimer's (the more common form of the disease) and also
why stroke and high blood pressure increase the likelihood of developing
Alzheimer's. Researchers are now testing potential compounds to halt, or
even prevent, the complex cascade of events caused by the presence of
p25 that lead to neurodegeneration. The work may also suggest an
intervention after stroke to lower or prevent additional risk of
Alzheimer's.
The report was presented on June 15 at the annual meeting of the American
Society for Biochemistry and Molecular Biology (ASBMB)/8th International
Union of Biochemistry and Molecular Biology Conference (IUBMB) in
Boston.
http://www.eurekalert.org/pub_releases/2004-06/foas-api060304.htm
Antibody detection in Alzheimer's may improve diagnosis, treatment
A study has found that people with Alzheimer’s disease have three to
four times more antibodies to RAGE (receptor for advanced glycation end
products) and beta amyloid — both major players in Alzheimer’s — than
their healthy counterparts. The ability to measure these specific
antibody levels could lead to a method for very early diagnosis. The
finding may also point to a new treatment approach. The study supports
the theory that autoimmunity and resulting inflammation play a big role
in Alzheimer’s.
The report is scheduled for publication in the September issue of
Neurobiology of Aging.
Full reference
http://www.eurekalert.org/pub_releases/2004-06/mcog-adi060204.htm
Progress on Alzheimer's vaccine
Efforts to create a vaccine for Alzheimer’s have been hindered by
potential side effects — some human participants in an earlier trial
developed severe inflammation in the brain. A mouse study has now
substantially increased the safety of the vaccine by including a tetanus
toxin to alter the immune response. Future studies are planned using the
herpes virus.
The work was published on-line June 25 in
Neurobiology of Aging.
Reference
http://www.eurekalert.org/pub_releases/2004-06/uorm-hta062904.htm
May
Diabetics at significantly higher risk for Alzheimer's disease
New findings from the Religious Orders Study add to research
suggesting a link between diabetes mellitus and an increased risk of
developing Alzheimer's disease. Some aspects of cognitive function
appear to be affected differently than others, in particular
perceptual speed declined significantly faster in those with
diabetes.
The study appeared in the May issue of the
Archives of Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2004-05/rpsl-das051204.htm
Enhanced counseling eases depression among caregivers
A new report from of the NYU Spouse-Caregiver Intervention Study shows
that a six-session counseling and long-term support program
substantially eases the depression of people caring for a loved one with
Alzheimer’s, and that the mental health benefits apparently are long
lasting. The study involved 406 caregivers, half of whom received the
usual counseling--sessions provided on an ad-hoc basis upon request
(control group). The other half was given three additional types of
counseling: two sessions of individual counseling, four sessions of
counseling with their family, and then weekly meetings with a support
group of fellow caregivers. After one year, some 45% of the control
group had symptoms of clinical depression, compared with 30% of those
who had received special counseling. This group still showed fewer
symptoms of depression on average than those in the control group three
years later. There was no difference after five years. It was suggested
that key factors in the enhanced treatment program were having the same
counselor for all sessions, the use of multiple types of coordinated
therapy, and counseling tailored to the particular coping challenges
that each of the caregivers and their families were dealing with.
The study was published in the May 1 issue of the
American Journal of Psychiatry.
Full reference
http://www.eurekalert.org/pub_releases/2004-05/nyum-ece042704.htm
Protein found that dissolves amyloid fibers
Amyloid plaque is extremely tough — so tough researchers have been
unable to find a means to attack them. A new study suggests that yeast
may be the means. Oddly, the yeast protein seems to be involved both in
making amyloid fibers, and in dissolving them. The yeast protein Sup35
sometimes forms amyloid fibers in yeast cells — this is part of the
cell's normal biology, changing the types of proteins that the cell
makes. Another protein — Hsp104 — appears to affect Sup35's ability to
form amyloid fibers. When a yeast cell contained either high amounts of
Hsp104 or none at all, amyloid fibers never formed. But when Hsp104
levels were small, the fibers flourished. In the latest study,
researchers found that small amounts of Hsp104 catalyzed the formation
of amyloid fibers, but large levels of the protein actually caused the
fibers to dissolve. Interestingly, Hsp104 belongs to a class of proteins
that sometimes are influenced by environmental factors.
The study was published online 20 May in Science.
http://www.eurekalert.org/pub_releases/2004-05/wifb-rdp052004.htm
New reliable test for Alzheimer's
A new test for Alzheimer’s promises a reliable means ofdiagnosing
Alzheimer’s in a living patient. Combined with clinical assessment,
testing blood flow in a specific region of the brain may boost the
degree of diagnostic certainty in difficult cases from 90% to almost
100%. The test involves use of single-photon emission computed
tomography (SPECT) — a radioisotope test that produces a
three-dimensional picture of the amount of blood flowing in certain
regions of the brain — to identify a characteristic sign of Alzheimer's
disease (reduced blood flow in the posterior cingulate cortex) and
distinguish it from a group of illnesses known as frontotemporal
diseases, which comprise the second-leading cause of dementia in the
elderly. The test did fail to identify Alzheimer’s patients with an
atypical form of Alzheimer’s known as tangle-predominant AD. This form
of Alzheimer’s also appears to be resistant to drugs currently used to
help treat Alzheimer’s. Evidence of shrinkage in brain structures such
as the hippocampus and parietal cortex is also central to diagnosing
Alzheimer's. This atrophy can be seen on a standard MRI.
The study appeared in the May edition of the Journal
of Nuclear Medicine.
Full reference
http://www.eurekalert.org/pub_releases/2004-05/uots-rin050404.htm
http://www.eurekalert.org/pub_releases/2004-05/sonm-sis050504.htm
April
Inactivation of Alzheimer's genes in mice causes dementia and brain degeneration
Mutations in two related genes known as presenilins are the major cause
of early onset, inherited forms of Alzheimer's disease, but how these
mutations cause the disease has not been clear. Since presenilins are
involved in the production of amyloid peptides (the major components of
amyloid plaques), it was thought that such mutations might cause
Alzheimer’s by increasing brain levels of amyloid peptides. Accordingly,
much effort has gone into identifying compounds that could block
presenilin function. Now, however, genetic engineering in mice has
revealed that deletion of these genes causes memory loss and gradual
death of nerve cells in the mouse brain, demonstrating that the protein
products of these genes are essential for normal learning, memory and
nerve cell survival.
The study appeared in the April 8 issue of Neuron.
Full reference
http://www.eurekalert.org/pub_releases/2004-04/cp-ioa032904.htm
Patients' medications eases caregiver distress
In a new analysis of an earlier study, researchers have discovered that
the drugs currently used to alleviate the symptoms of Alzheimer’s not
only help confusion and memory loss, but also alleviates or delays
symptoms like agitation, depression, and psychosis, and thus have
flow-on effects of alleviating the burden on caregivers. For patients
not already exhibiting behavioral problems, treatment with galantamine
delayed their symptoms for more than three years on average. This is
added impetus to treat patients with dementia with cholinesterase
inhibitors as early as possible.
The report appeared in the March issue of the
American Journal of Psychiatry.
Full reference
http://www.eurekalert.org/pub_releases/2004-04/uorm-crt040504.htm
Rate of brain volume loss predicts dementia
A new study has found that rates of total brain volume loss may help
identify patients with mild cognitive impairment who are at high risk of
developing dementia. The study followed 55 people over 14 years, and
found that loss of volume in the hippocampus predicted which mildly
cognitively impaired individuals would stay stable and which would
decline to Alzheimer's with 70% accuracy, while the rate of total brain
volume loss was 62% accurate in predicting cognitive outcome. Combining
both variables produced the strongest model: 75% accuracy. The discovery
could help doctors plan early treatment strategies and prevention
studies.
The study was presented at the 56th annual meeting of the American Academy
of Neurology in San Francisco.
http://www.eurekalert.org/pub_releases/2004-04/ohs-osr042804.htm
Preliminary results promising in Alzheimer's gene therapy trial
A small, preliminary study has had some success in delaying brain cell
loss in early Alzheimer’s patients through the surgical placement of
genetically modified tissue directly into their brains.
The study was reported on April 27 at the American Academy of Neurology
meeting in San Francisco.
http://www.eurekalert.org/pub_releases/2004-04/uoc--pra042204.htm
March
New PET technique improves accuracy of early diagnosis of Alzheimer's
A new
study identifies a new Positron Emission Tomography (PET) scanning technique
that may increase the already high accuracy of PET in diagnosing Alzheimer’s at
a very early stage. Altered brain connections between the entorhinal cortex and
both hemispheres of the brain can be clearly identified with 18F-FDG PET. The
entorhinal cortex is a critical site for learning and memory. It now appears
that most of its connections to the neocortex in both hemispheres are destroyed
at a very early stage of Alzheimer’s.
The study appeared in the March issue of The
Journal of Nuclear Medicine.
Full reference
http://www.eurekalert.org/pub_releases/2004-03/sonm-nss031104.htm
A new hypothesis about Alzheimer's
A new theory about the cause of Alzheimer's disease has been proposed.
According to this theory, Alzheimer’s arises as a consequence of
inflammation, which creates abnormal metabolites out of normal brain
molecules. These abnormal metabolites then modify "amyloid beta"
proteins in the brain and cause them to misfold, thus accumulating into
the fibrils and plaques characteristic of the disease. The inflammation
process that creates these metabolites can be triggered by numerous
stimuli, including infections that precede the onset of Alzheimer's
disease by a significant amount of time — perhaps years. Traumatic head
injuries, for example, are a major risk factor for later developing
Alzheimer's disease. Inflammation is increasingly seen as playing a role
in neurodegenerative diseases.
The theory was published online March 19 in
Proceedings of the National Academy of Sciences.
Full reference
http://www.eurekalert.org/pub_releases/2004-03/sri-anh031504.htm
Loss of smell linked to key protein in Alzheimer's disease
Loss of smell is one of the first clinical signs of Alzheimer’s and
Parkinson’s disease. Now researchers have linked smell loss in
genetically altered mice with excessive levels of a key protein
associated with these diseases. If smell function declines as the levels
of this protein increase in brain regions associated with smelling, the
research could validate the use of smell tests for diagnosing
Alzheimer's disease.
Their findings appear in the March 12th issue of
Brain Research, the commemorative volume 1000.
Full reference
http://www.eurekalert.org/pub_releases/2004-03/uopm-los030304.htm
February
Genes influence memory in families with Alzheimer's disease
A study of 1,036 people from 266 families, most of whom had more than
one person living with Alzheimer's in the extended family, found that
about half of the variation in memory performance among individuals was
due to genetics. The influence of genetics was not as strong in the
areas of attention, abstract reasoning, language and visual-spatial
ability. The genetic influence seemed to have little to do with the gene
apolipoprotein E, known to increase the risk of developing Alzheimer's.
It should be noted, however, that participants in the study had an
average of only six years of education.
The study was published in the February 10 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2004-02/aaon-gim020304.htm
Research clarifies how Alzheimer's medicines work
New research clarifies how cholinesterase inhibitors alleviate
mild-to-moderate Alzheimer's. When scientists chemically blocked
receptors for an important neurotransmitter called acetylcholine, even
healthy young people found it significantly harder to learn and remember
– especially in the face of interference. Cholinesterase inhibitors slow
the breakdown of acetylcholine. The finding also helps explain why
Parkinson's disease, dementia due to multiple strokes, multiple
sclerosis and schizophrenia, are all also associated with memory
problems — all these conditions, like Alzheimer’s, are associated with
lower levels of acetylcholine in the brain.
The study appeared in the February issue of
Behavioral Neuroscience.
Full reference
(Full text of the article is available at
http://www.apa.org/journals/bne/press_releases/february_2004/bne1181223.html
)
http://www.eurekalert.org/pub_releases/2004-02/apa-rch020904.htm
Why diet, hormones, exercise might delay Alzheimer’s
A theory that changes in fat metabolism in the membranes of nerve cells
play a role in Alzheimer's has been supported in a recent study. The
study found significantly higher levels of ceramide and cholesterol in
the middle frontal gyrus of Alzheimer's patients. The researchers
suggest that alterations in fats (especially cholesterol and ceramide)
may contribute to a "neurodegenerative cascade" that destroys neurons in
Alzheimer's, and that the accumulation of ceramide and cholesterol is
triggered by the oxidative stress brought on by the presence of the
toxic beta amyloid peptide. The study also suggests a reason for why
antioxidants such as vitamin E might delay the onset of Alzheimer's:
treatment with Vitamin E reduced the levels of ceramide and cholesterol,
resulting in "a significant decrease in the number of neurons killed by
the beta amyloid and oxidative stress.
The study was published in the February 17 issue of
Proceedings of the National Academy of Sciences.
Full reference
http://www.eurekalert.org/pub_releases/2004-02/aaft-nsm021004.htm
January
New drug approved for moderate to severe Alzheimer's
The FDA recently approved memantine for treatment of moderate to
severe Alzheimer’s. The drug has been used for some 20 years in Germany.
While memantine significantly improved performance in Alzheimer’s
sufferers in studies, the effect, as with all Alzheimer’s drugs
currently in use, is small.
The report appeared in the 21 January issue of the
Journal of the American Medical Association.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/uorm-jsc012004.htm
http://www.eurekalert.org/pub_releases/2004-01/jaaj-ndi011504.htm
Gene targeting prevents memory loss in Alzheimer's disease model
A new mouse study presents new evidence that beta-amyloid is directly
responsible for causing the memory loss seen in Alzheimer's, and
provides compelling evidence for the therapeutic potential of inhibiting
an enzyme, beta-secretase (BACE1), required for the production of
beta-amyloid. The mice were genetically engineered to lack the enzyme.
The study was published in the January 8 issue of
Neuron.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/nu-gtp010504.htm
More sensitive test norms better predict who might develop Alzheimer's disease
Early diagnosis of Alzheimer's is becoming more important with new
medical and psychological interventions that can slow (but not stop) the
course of the disease. Given this, it is suggested that more sensitive
testing may be necessary for highly intelligent people, who, on average,
show clinical signs of Alzheimer's later than the general population.
Once they show such signs, they decline much faster. A study of 42 older
people with IQ's of 120 or more, used two different test norms to
forecast problems: the standard norm, derived from a large cross-section
of the population, or an adjusted high-IQ norm that measured changes
against the individual's higher ability level. The raised cutoffs
predicted that 11 of the 42 individuals were at risk for future decline
– compared with standard cutoffs, which indicated they were normal. True
to the former prediction, three and a half years later, nine of those 11
people had declined. Six of those went on to develop mild cognitive
impairment (MCI), a transitional illness from normal aging to a dementia
(of which one type is Alzheimer's). Five of these individuals have since
received a diagnosis of Alzheimer's disease, two years after this study
was submitted. It is also suggested that, at the other end of the scale,
those with below-average intelligence have the potential for being
misdiagnosed as 'demented' when they are not, and the norms should be
adjusted downwards accordingly.
This finding is reported in the January issue of
Neuropsychology.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/apa-mst122903.htm
New technique allows sight of amyloid plaque in living brains
The first human study has now been completed of a compound that,
through PET scanning, enables researchers to see the amyloid plaque
deposits in the brains of Alzheimer’s sufferers. The compound has been
dubbed Pittsburgh Compound B (PIB), and should be a very useful new tool
in Alzheimer’s research.
The study was reported in the March issue of Annals
of Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/uopm-uop012104.htm
New method of distinguishing Alzheimer's from Lewy body dementia
Looking at specific changes in alertness and cognition may provide a
reliable method for distinguishing Alzheimer's from dementia with Lewy
bodies (DLB) and normal aging. Four characteristics significantly
distinguished patients with DLB from persons with Alzheimer’s and normal
elderly controls: daytime drowsiness and lethargy despite getting enough
sleep the night before; falling asleep two or more hours during the day;
staring into space for long periods and episodes of disorganized speech.
"For the normal elderly control group, one or two of these behaviors was
found in only 11 percent of the group. For the patients with AD, one or
two of these behaviors were not uncommon, but over 63% of the patients
with DLB had three or four of these behaviors.” DLB accounts for as much
as 20 to 35% of the dementia seen in the United States.
The study appeared in the January 27 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/ama-nmo010804.htm
Using vitamin E and C supplements together may reduce risk of Alzheimer disease
A study involving 4,740 elderly (65 years or older) found the greatest
reduction in both prevalence and incidence of Alzheimer's in those who
used individual vitamin E and C supplements in combination, with or
without an additional multivitamin. There was no significant benefit in
using vitamin C alone, vitamin E alone, or vitamin C and multivitamins
in combination.
The study appeared in the January issue of the
Archives of Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/jaaj-uve011404.htm
Low free testosterone levels linked to Alzheimer's disease in older men
A study evaluating the testosterone levels of 574 men, ages 32 to 87,
who participated in the Baltimore Longitudinal Study of Aging (BLSA),
found that older men with lower levels of free, or unbound, testosterone
circulating in their bloodstreams were apparently at higher risk of
developing Alzheimer's than their peers. This is believed to be the
first study to associate low circulating blood levels of free
testosterone with Alzheimer’s years before diagnosis. Previously, the
same researchers had found that older men with high levels of
circulating free testosterone have better visual and verbal memory and
perform spatial tasks more adeptly than their peers.
The study appeared in the January 27 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2004-01/naos-lft012804.htm
