The recent failure of an Eli Lilly clinical trial to test a promising drug highlights our lack of understanding about the cause of Alzheimer’s disease (see New York Times article).
The Amyloid beta hypothesis, which is the prevalent idea today, states in its simplest form that the accumulation of Amyloid beta protein in the brain causes brain cells to die and, therefore, leads to symptoms of Alzheimer’s disease.
The Amyloid beta hypothesis is based on the observation that an extraordinary accumulation of Amyloid beta protein is seen in the brains of known Alzheimer’s disease patients. The problem is that this is a correlation and does not necessarily point to a cause.
There are a number of other possible interpretations for Amyloid beta accumulation including possibly a response by the body to protect the brain from the ravages of Alzheimer’s disease.
Perhaps Amyloid beta accumulation in the brain is similar to the scab that forms after we scrape our skin? The scab doesn’t cause the skin damage but is formed by the body to help repair and protect the skin.
Amyloid beta may or may not be important in the cause of Alzheimer’s disease but we must keep in mind that at this time we only know correlations. We do not know the cause.
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[…] A new review of processes underlying Alzheimer’s disease by Dr. Karl Herrup presents a new synthesis and framework to view this debilitating illness. The current standard view of the cause of Alzheimer’s disease is known as the Amyloid Cascade Hypothesis. The existence of amyloid beta plaques in the brains of Alzheimer’s disease patients lead to the idea that the plaques may be the cause of the disease (see my earlier blog post “Wrong Idea for Cause of Alzheimer’s Disease?“). […]
[…] Wrong Idea for Cause of Alzheimer’s Disease? […]