Scientists have identified two proteins that may help prevent the brain plaques that are linked to Alzheimer's disease.
The proteins appear to work in tandem to orchestrate removal of potentially hazardous molecules from the brain.
However, unless the two are in the correct balance they actually seem to promote deposition of the amyloid protein which forms the plaques.
The research, by Washington University of Medicine, St Louis, is published in the journal Neuron.
The key proteins are called apoliprotein E (apoE) and clusterin.
We've known for a few years that mutations in the apoE gene increase the risk of Alzheimer's. So this is an amazing extension of those results. Very exciting.
It will not be the whole story. We've seen in Parkinson's Disease that a single "disease" is really the endpoint of a number of different genetic and environmental combinations. Alzheimer's Disease (really Alzheimer's Syndrome) is likely similar; when we're done we'll have redefined the syndrome and named the pathways.
Since Alzheimer's appears to be an acceleration of the "normal" aging of the human brain, it's possible that any treatments for Alzheimer's will extend the elasticity and capability of most adult brains. Were that to happen, our social security crisis may evaporate.
On the other hand, there's evidence that prions are critical to memory formation. Some Alzheimer's treatments may erase existing memories, or interfere with memory formation.