News reports of research into Alzheimer's disease Jan - June 2007
To search by subject, go to Alzheimer's subject index.
Return to Alzheimers main page for monthly index
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
Mental stimulation in old age reduces Alzheimer's risk
Post-mortem analysis of participants in a large, long-running study
has provided more support for the idea that mental stimulation protects
against Alzheimer’s. The study found a cognitively active person in old
age was 2.6 times less likely to develop dementia and Alzheimer’s
disease than a cognitively inactive person in old age. This association
remained after controlling for past cognitive activity, lifetime
socioeconomic status, and current social and physical activity. Frequent
cognitive activity during old age was also associated with reduced risk
of mild cognitive impairment.
The study was published online ahead of print June 27 in
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-06/aaon-fbs061907.htm
Alzheimer’s most often found in combination with other disease
Post-mortem data from a large, long-running study has found that only
30% of people with signs of dementia had Alzheimer’s disease alone. 42%
had Alzheimer’s disease with cerebral infarcts (strokes) and 16% had
Alzheimer’s disease with Parkinson’s disease (including two people with
all three conditions). Infarcts alone caused another 12% of the cases.
Vascular dementia caused another 12%. In those without dementia,
brain autopsy revealed the presence of Alzheimer’s in 24% of cases, and
infarctions in 18%. The finding that Alzheimer’s pathology with cerebral
infarcts is a very common combination in people with dementia adds to
emerging evidence that dementia risk might be reduced with the same
tools we use for cardiovascular disease such as control of blood
cholesterol levels and hypertension.
The findings appeared online ahead of print June 13 in
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-06/nioa-sfm061207.htm
Simple test predicts 6-year risk of dementia
A 14-point index combining medical history, cognitive testing, and
physical examination — a simple test that can be given by any physician
— has been found to predict a person’s risk for developing dementia
within six years with 87% accuracy. As measured by the index, the risk
factors for developing dementia are an age of 70 or older, poor scores
on two simple cognitive tests, slow physical functioning on everyday
tasks such as buttoning a shirt or walking 15 feet, a history of
coronary artery bypass surgery, a body mass index of less than 18, and
current non-consumption of alcohol. The results do need to be validated
in other populations — for example, they have not yet been tested on
Hispanics or Asian-Americans.
The tests were described in a presentation at the 2007 International
Conference on Prevention of Dementia, in Washington, DC.
http://www.eurekalert.org/pub_releases/2007-06/uoc--stp060707.htm
New Alzheimer's gene
A study comparing more genetic markers in the DNA of people with and
without Alzheimer’s disease than ever before has revealed a new gene
that may increase a person’s risk for developing Alzheimer’s disease.
The gene — GAB2 — appears to modify an individual’s risk when associated
with other genes, including
APOE4. It’s suggested that the
healthy form of the GAB2 gene protects brain cells from developing
tangles. If confirmed, this discovery could provide a target for future
therapeutic drugs.
The results appeared in the June 7 issue of
Neuron.
Full reference
http://www.eurekalert.org/pub_releases/2007-06/ttgr-rti060107.htm
Why stress increases Alzheimer's risk
Previous research has suggested that stress may increase risk of
Alzheimer's disease. Now a mouse study suggests the mechanism that may
underlie this increased risk. Corticotropin-releasing factor (CRF) is
released in the mouse brain by stress, and this factor is linked to
increased levels of brain cell communication. A previous study has shown
that increased communication between brain cells also contributes to
increased amyloid beta.
When CRF was directly placed in the mouse brain, amyloid beta levels
rose immediately, while mice given a CRF blocker and then stressed did
not display increased amyloid beta.
The results were reported in the June 19 issue of the
Proceedings of the National Academy of Sciences.
Full reference
http://www.eurekalert.org/pub_releases/2007-06/wuso-bsp053107.htm
Another mouse study has also found evidence
suggesting that stress has its negative effects through the two known
corticotropin-releasing factor receptors, CRFR1 and CRFR2. Mice
genetically engineered to lack either CRFR1 or CRFR2 revealed that, in
the absence of CRFR1, stress-induced tau
tangles was prevented,
while in mice missing CRFR2 the effect of stress on
tau protein was amplified.
The findings appeared in the June 13 issue of
Journal of Neuroscience.
Full reference
http://www.eurekalert.org/pub_releases/2007-06/si-apm061407.htm
May
Brain scans show early Alzheimer's disease in people with memory problems
PET scans performed on the brains of 13 elderly men and women with mild
cognitive impairment (MCI) and 14
elderly people without memory problems found that those with MCI had as much
as 39% more
PIB uptake in some parts of the
brain than people without MCI, and about half of the MCI patients had PIB
uptake in the Alzheimer's disease range. MCI subjects with at least one
APOE 4 allele tended to have higher PIB uptake than MCI subjects
without
APOE 4. PIB is an imaging agent that allows
amyloid plaque to be seen and
measured.
The study was published in the May 8 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-05/aaon-bs050107.htm
Reduction of tau protein protects against Alzheimer’s
A study using genetically
engineered mice has found that when
tau protein was reduced their memory function was retained and they
lived a normal lifespan, even though
amyloid-beta levels weren’t
affected. They were also made mice more resistant to epileptic seizures.
The findings were reported in the May 4 issue of
Science.
Full reference
http://www.eurekalert.org/pub_releases/2007-05/gi-sin042707.htm
Personality changes may help detect Lewy bodies dementia
Dementia with Lewy bodies is the second most common neurodegenerative
cause of dementia. It shares characteristics with both Alzheimer's and
Parkinson's disease, but some medications used to treat Alzheimer's patients
are potentially dangerous for people with dementia with Lewy bodies. Early
diagnosis is therefore important. A new study has found that people with
dementia with Lewy bodies often display passive personality changes some
time before cognitive deficits are evident, offering hope that a simple
personality test might help diagnosis.
The study was published in the May 29 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-05/aaon-pcm052107.htm
Breakdown of myelin implicated in Alzheimer's
Myelin coats the axons of
nerves, allowing for efficient conduction of nerve impulses, and thus faster
processing speeds. Unfortunately, it becomes more and more susceptible to
damage as we age. A new study suggests that it is the breakdown of myelin
that promotes the buildup of
amyloid-beta fibrils, that in turn destroy more and more myelin. The
idea suggests a new therapeutic approach.
The report appeared in the April issue of Alzheimer's
& Dementia.
Full reference
http://www.eurekalert.org/pub_releases/2007-05/uoc--bom051007.htm
Blood inflammation plays role in Alzheimer's disease
Data from the Framingham Heart Study has found that those with the
highest amount of cytokines (protein messengers that trigger inflammation)
in their blood were more than twice as likely to develop Alzheimer's disease
as those with the lowest amount of cytokines, providing further evidence
that inflammation plays a role in the development of Alzheimer's disease.
The study was published in the May 29 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-05/aaon-bip052107.htm
Alzheimer's weight gain initiative improved patients' intellectual abilities
In a small, three-month study, Swedish researchers have found a way to
increase the weight of people with Alzheimer's, with consequent improved
intellectual abilities, by improving communication and patient involvement,
altering meal routines and providing a more homely eating environment.
The findings were published in the May issue of the
Journal of Clinical Nursing.
Full reference
http://www.eurekalert.org/pub_releases/2007-05/bpl-awg051507.htm
Conference proceedings
Some hypertension drugs may help reduce dementia risk
Data from the Cardiovascular Health Study, a long-term study of
cardiovascular risk factors that involved 5,888 people over 65 years old,
has studied 1,074 participants who were free of dementia when they entered
the study and who were being treated for high blood pressure. They found use
of a class of high blood pressure medicines that are centrally active ACE
inhibitors was associated with lower risk of cognitive decline. The benefit
did not result from ACE inhibitors in general, only to those that are
centrally active (which means they can cross the blood brain barrier).
Centrally acting drugs include captropril (Capoten®), fosinopril
(Monopril®), lisinopril (Prinivil® or Zestri®), perindopril (Aceon®),
ramipril (Altace®) and trandolapril (Mavik®).
The findings were reported today at the annual meeting of the American
Geriatrics Society in Seattle.
http://www.eurekalert.org/pub_releases/2007-05/wfub-shd042707.htm
Estrogen use before 65 linked to reduced risk of Alzheimer's disease
Data from the Women’s Health Initiative Memory Study looked at prior
hormone use in 7,153 healthy women ages 65-79 before they enrolled in the
WHI Memory Study, and followed their cognitive health over an average of
five years. In that time, 106 of the women developed Alzheimer’s disease or
dementia. The study found women who used any form of estrogen hormone
therapy before the age of 65 were nearly 50% less likely to develop
Alzheimer’s disease or dementia than women who did not use hormone therapy
before age 65, but women who began estrogen-only therapy after the age of 65
had roughly a 50% increased risk of developing dementia. The risk jumped to
nearly double for women using estrogen-plus-progestin hormone therapy.
The findings were presented at the American Academy of Neurology’s 59th
Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.eurekalert.org/pub_releases/2007-05/aaon-eub041007.htm
Secondhand smoke increases risk of dementia
Preliminary findings from the Cardiovascular Health Study indicates that
elderly people with high lifetime exposure to secondhand smoke (more than 30
years) were approximately 30% more likely to develop dementia than those
with no lifetime secondhand smoke exposure. People with abnormalities of
their carotid arteries and high lifetime exposure to secondhand smoke were
nearly two-and-a-half times as likely to develop dementia as those with no
secondhand smoke exposure and no indications of carotid artery disease.
Haight presented the findings at the American Academy of Neurology’s 59th
Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.eurekalert.org/pub_releases/2007-05/aaon-ssi041007.htm
April
Diabetes associated with increased risk of mild cognitive impairment
A study involving 918 individuals older than 65 years (average age 75.9)
who did not have mild cognitive disorder or dementia when they enrolled has
found that, over some 6 years, diabetes was related to a significantly
higher risk of developing
amnesic mild cognitive impairment,
after controlling for other risk factors. The results support other findings
that type 2 diabetes increases the risk of Alzheimer's.
The report appeared in the April issue of Archives of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-04/jaaj-dmb040507.htm
DHA-rich diet may curb onset of Alzheimer’s
Studies with genetically engineered
mice have revealed that a type of omega-3 fatty acid — docosahexaenoic
acid (DHA) — may slow the growth of
beta amyloid and
tau, the
proteins that lead to the
lesions typical of Alzheimer’s. The results also suggest that DHA works
better on its own than when paired with omega-6 fatty acids. A typical
American diet has a ratio of omega-6 fatty acids to omega-3 fatty acids of
10:1, while studies indicate that the ideal ratio for good health is 3:1 to
5:1. Omega-6 fatty acids are found in corn, peanut and sunflower oils.
This research appears in the April 18 issue of The
Journal of Neuroscience.
Full reference
http://www.eurekalert.org/pub_releases/2007-04/uoc--ofa041307.htm
Enhanced environment restores memory in mice with neurodegeneration
Research involving genetically
engineered mice has found that mice whose brains had lost a large number
of neurons due to neurodegeneration regained long-term memories and the
ability to learn after their surroundings were enriched with toys and other
sensory stimuli. The same effect was also achieved through the use of a drug
that encourages neuronal growth. The findings suggest not only new
approaches to treatment for those with Alzheimer's or other
neurodegenerative diseases, but also supports recent suggestions that
"memory loss" may be an inaccurate description of the kinds of mental
deficits associated with neurodegenerative diseases. The memories are still
there; they are simply inaccessible.
The findings were published online ahead of print April 29 in
Nature.
Full reference
http://www.eurekalert.org/pub_releases/2007-04/hhmi-eer042507.htm
Commonly used pain medications do not prevent Alzheimer's
Contradicting earlier indications, a study involving more than 2,100
people over age 70 with no signs of dementia but a family history of
Alzheimer's disease, has found no benefit from over-the-counter pain
medication naproxen and prescription pain reliever celecoxib. Participants
were randomly assigned daily doses of naproxen, celecoxib, or placebo for up
to four years, but most participants had received the treatments for less
than two years.
The study was published online ahead of print April 25 in
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-04/aaon-cup042407.htm
Brain structure changes years before memory loss begins
Another study provides evidence that people who develop dementia or
Alzheimer's disease experience brain structure changes years before any
signs of memory loss begin. The study involved 136 people over the age of 65
who were considered cognitively normal at the beginning of the five-year
study. By the end of the study, 23 people had developed
MCI, and nine of the 23 went on
to be diagnosed with Alzheimer's disease. Compared to the group that didn't
develop memory problems, the 23 who developed MCI or Alzheimer's disease had
less
gray matter in key
memory processing areas (specifically,
anteromedial temporal
lobes and left
angular gyrus) even at the beginning of the study when they were
cognitively normal. They also had lower cognitive test scores, though these
scores were still within normal range.
The study was published in the April 17 issue of
Neurology.
Full reference
http://www.eurekalert.org/pub_releases/2007-04/aaon-bsc041007.htm
Statin treatment improves spatial memory in Alzheimer's mice
Treatment with the cholesterol-lowering
statin drug Simvastatin
significantly improved spatial in
genetically engineered mice. The
benefits were more pronounced in males. Levels of nNOS (neuronal nitric
oxide synthase) levels were significantly higher in the
hippocampus and
cortex of statin
treated groups as compared to similar mice that did not receive statin. nNOS
is responsible for the release of nitric oxide, a substance that causes
dilation of the blood vessels in the brain, thus increasing blood flow.
The findings were presented April 30 at Experimental Biology 2007 in
Washington, DC.
http://www.eurekalert.org/pub_releases/2007-04/foas-sti042107.htm
March
Survey reveals ethnic differences in knowledge about Alzheimer's
The Alzheimer's Foundation of America's (AFA) second Investigating Caregivers' Attitudes and Needs survey has revealed that African-American and Hispanic caregivers of people with Alzheimer's disease are significantly more likely (37% and 33%, respectively) than caregivers of other races (23%) to consider the disease a normal part of the aging process and also more likely (70% and 67%, vs 53%) to dismiss its symptoms as part of getting older, thus delaying diagnosis. They were also more likely (67% and 63%, vs 49%) to report that they did not know enough about the disease to recognize the symptoms.
Fears of stigma also play a part in delaying diagnosis, with around one-third (33%) of respondents reporting that their loved one's concern about stigma delayed diagnosis, and about a quarter (26%) indicating that their own concern about stigma contributed to the delay. African-American caregivers were significantly more concerned about stigma (36%) than Hispanic (22%) and other race (18%) caregivers.
Races other than African-American and Hispanic were far more likely to
consider placing their loved one in a facility: 32% compared to
African-American (19%) and Hispanic (21%) caregivers. African-American and
Hispanic caregivers were more likely to use a support groups than other
races (47% and 50%, vs 29%). Yet only around half of African-American
respondents and a little more than one-third of Hispanic respondents said
that they felt the support groups they were able to access were appropriate
to their specific religious or ethnic background. At diagnosis, caregivers
overall wished they had received more information about Alzheimer's disease
(75%) and treatment options (75%), with African-American caregivers (83%)
significantly more likely than Hispanic (73%) and other (68%) caregivers to
wish they had received more information.
http://www.eurekalert.org/pub_releases/2007-03/fi-srm030907.htm
Study examines genetic risk factors for Alzheimer's disease
A Welsh study that tested more than 17,000 gene variants in 4,000
volunteers has found evidence for several genes contributing to Alzheimer’s
disease, the most interesting one being GALP, thought to affect the
development of
tangles within brain cells.
The findings will be published in a future issue of
Human Molecular Genetics.
http://www.eurekalert.org/pub_releases/2007-03/cu-seg030507.htm
February
Loneliness increases risk of Alzheimer's disease
Social isolation has been linked with an increased risk of dementia and
cognitive decline, but perceived isolation — feeling alone rather than being
alone — hasn’t been investigated. A new four-year study of 823 older adults
provides evidence that loneliness is a risk factor for Alzheimer’s. 76
individuals developed Alzheimer’s over the course of the study, and the risk
of developing it increased around 51% for each point on the 5-point
loneliness score. The findings did not change significantly when the
researchers factored in markers of social isolations, such as a small
network and infrequent social activities. Autopsies performed on 90
individuals who died during the study show that loneliness is a risk factor
rather than an early sign of the disease.
The study was published in the February issue of
Archives of General Psychiatry.
Full reference
http://www.eurekalert.org/pub_releases/2007-02/rumc-law020207.htm
http://pn.psychiatr
Vasectomy may put men at risk for type of dementia
A small survey of men with Primary Progressive Aphasia (PPA), a
neurological disease in which people have trouble recalling and
understanding words, has found that 40% of them had had a vasectomy, in
comparison to 16% of controls. Additionally, of those who had PPA, those who
had undergone a vasectomy developed it at a younger age (58 years) than
those who hadn't had one (62 years). Preliminary evidence from the study
also indicates a possible link between frontotemporal dementia and a
vasectomy. No such association was found with Alzheimer’s.
http://www.eurekalert.org/pub_releases/2007-02/nu-vmp021207.htm
http://www.northwestern.edu/newscenter/stories/2007/02/vasectomy.html
More on why high cholesterol might increase your risk of Alzheimer’s
A cell study provides more understanding of why there might be a link
between cholesterol and Alzheimer's disease. The study found that proteins
which help control cholesterol levels in arterial walls were also present in
neurons, and when the genes for these proteins were over-expressed,
production of
amyloid beta protein fell.
The finding suggests a new approach to slowing Alzheimer’s. The study also
showed that the apoE protein is
extremely good at regulating cholesterol removal from neurons — the gene for
this protein is a well-known genetic risk factor for Alzheimer's.
The study appeared in the February issue of the
Journal of Biological Chemistry.
http://www.newscientist.com/article/mg19325905.200?DCMP=NLC-nletter&nsref=mg19325905.200
Inhaled anesthetics might increase the risk of Alzheimer's
A study using a new imaging technique has been able to see why
anesthetics might cause amyloid
β peptides to clump together, and whether one method of anesthesia was
better than another. Previous studies have found that the inhaled
anesthetics halothane and isoflurane and the intravenous anesthetic propofol
encouraged the growth and clumping of Aβ in a test tube experiment. The new
study found that the inhaled anesthetics caused the highest levels of Aβ
aggregation, while the injected anesthetic propofol only interacted and
caused aggregation at high concentrations, and thiopental did not cause the
clustering of Aβ peptides even at high concentrations.
The study was published in the January 23 issue of
Biochemistry.
Full reference
http://www.eurekalert.org/pub_releases/2007-01/uopm-roa012507.htm
January
Bilingualism has protective effect in delaying onset of dementia
An analysis of 184 people with dementia (132 were diagnosed with
Alzheimer’s; the remaining 52 with other dementias) found that the
mean age of onset of dementia symptoms in the 91 monolingual
patients was 71.4 years, while for the 93 bilingual patients it was
75.5 years — a very significant difference. This difference remained
even after considering the possible effect of cultural differences,
immigration, formal education, employment and even gender as
influencers in the results.
The study was published in the February issue of
Neuropsychologia.
Full reference
http://www.eurekalert.org/pub_releases/2007-01/bcfg-css011107.htm
Learning slows physical progression of Alzheimer's disease
A mouse study has found that short but repeated learning sessions can
slow the development of two brain lesions that are the hallmarks of
Alzheimer's disease —beta amyloid
plaques, and
tau tangles. The researchers
are now investigating whether more frequent and vigorous learning will have
bigger and longer benefits.
The study appears in the January 24 issue of the
Journal of Neuroscience.
Full reference
http://www.eurekalert.org/pub_releases/2007-01/uoc--lsp011807.htm
Transdermal vaccine effective in treating Alzheimer's disease in mice
Previous research on an Alzheimer's vaccine proven safe and effective in
an animal model was suspended when the initial clinical trial caused brain
inflammation and death in a small percentage of patients. A new mouse study
has now had success with a transdermal method of delivery (a skin patch),
that doesn’t appear to trigger the toxic reaction of past immunization
strategies. Further research is needed to assess whether the transdermal
vaccine can curb memory loss as well as reduce
Ab
plaque.
The study was published online before print on January 30 in the
Proceedings of the National Academy of Sciences.
Full reference
http://www.eurekalert.org/pub_releases/2007-01/uosf-tve011807.htm
Books
for immediate download!
Now available as a downloadable ebook!
