Regular Consumption
of High Cholesterol Diet May Lead to Alzheimer’s Disease
New study used
rats to show brain damage produced from 5% cholesterol-enriched diet
Nov. 24, 2010 –
A new study indicates that regularly consumption of a high fat
cholesterol diet may lead to Alzheimer’s disease. The research using
adult rats is from the Laboratory of Psychiatry and Experimental
Alzheimers Research at the Medical University Innsbruck and was funded
by the Austrian Science Funds and published in Molecular Cellular
Neuroscience.
The risk of
developing Alzheimer’s disease is presumed to start as people reach 60
years of age, and less than 2.5 percent have a genetic disposition.
It is estimated
that in 2050, approximately 80 million people will suffer from
Alzheimer's disease worldwide, a severe neurodegenerative disorder of
the brain that is characterized by loss of memory and cognitive decline,
according to lead author of the study, Dr. Christian Humpel.
The causes for
Alzheimer's disease are not known, but impairment of amyloid-precursor
protein expression and beta-amyloid clearance is widely suspected
(beta-amyloid cascade).
Alternatively, a
pathological cascade of events may trigger hyper-phosphorylation of tau,
putting the tau-hypothesis into the center.
A third
hypothesis suggests that chronic long-lasting mild cerebrovascular
damage, including inflammatory processes and oxidative stress, may cause
Alzheimer's disease. It has been suggested that Alzheimer's disease
starts 20-30 years before first symptoms appear and recent studies have
shown, that high cholesterol levels are linked to the pathology of this
disease.
The aim of the
study led by Humpel was to study the effects of hypercholesterolemia in
adult rats, which were fed with normal food (control group) or with a
special 5% cholesterol-enriched diet (hypercholesterolemia group).
After 5 months
animals were tested for behavioral impairments and pathological markers
similar to those found in the brains of patients with Alzheimer's
disease.
The results
showed that chronic hypercholesterolemia caused memory impairment,
cholinergic dysfunction, inflammation, enhanced cortical beta-amyloid
and tau and induced microbleedings, all indications, which resemble an
Alzheimer's disease-like pathology.
Thus the data
are in line with earlier studies showing that high fat lipids, including
cholesterol, may participate in the development of sporadic Alzheimer's
disease.
However, since
Alzheimer's disease is a complex heterogenous disease, these data do not
allow the conclusion that cholesterol alone is responsible for the
disease, according to Dr. Humpel.
It can be
speculated that chronic mild cerebrovascular damage caused and
potentiated by different vascular risk factors (including cholesterol)
may contribute to these pathologies.
It needs to be
determined in future studies how mild chronic microvascular bleedings,
silent strokes and mild blood-brain barrier damage over decades may play
a role in the development of this disease.
The researchers
say several data support the view that Alzheimer's disease can be
considered as a vascular disease and that a dysfunctional clearance of
beta-amyloid from brain to blood and vice versa may be a secondary
important step in the cascade of initiation of the disease.
The study was
co-authored by PhD students, Celine Ullrich and Michael Pirchl.
>> Laboratory of Psychiatry and Experimental Alzheimers Research (http://www2.i-med.ac.at/psychlab/)
at the Medical University Innsbruck (Austria)
>> This study was supported by the Austrian Science Funds (P19122-B05).
Additional details are available in the full publication:
http:dx.doi.org/10.1016/j.mcn.2010.08.001
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boomers
Nov. 24, 2010 –
A new study indicates that regularly consumption of a high fat
cholesterol diet may lead to Alzheimer’s disease. The research using
adult rats is from the Laboratory of Psychiatry and Experimental
Alzheimers Research at the Medical University Innsbruck and was funded
by the Austrian Science Funds and published in Molecular Cellular
Neuroscience.
