External lipid entry into the brain through a damaged blood brain barrier causes Alzheimer's disease
What is it about?
This article explains why the current amyloid hypothesis is failing to produce effective treatments for Alzheimer's Disease. It says that beta-amyloid is not the main cause of damage to the brain, it is the entry of lipids from outside of the brain. This is only possible because the blood brain barrier (which normally keeps external lipids out) becomes damaged. This can happen as a result of ageing, brain trauma, high blood pressure, smoking and a number of other reasons, all of which have been identified as risk factors for AD. Beta-amyloid also damages the BBB, but is only the main cause of such damage in comparatively rare early-onset, inherited forms of the disease. Overall, ageing is the primary driver, explaining why it is almost exclusively the elderly get this disease. The BBB separates two very different lipid systems - one in the brain, one in the rest of the body. Damage to the BBB exposes the brain to the external system and AD is the result.
Why is it important?
It provides a totally different way of understanding Alzheimer's Disease. As a result, it provides entirely new ways of testing, preventing and treating the disease.