Beta- Amyloid gets piggy back ride to brain.

Main Entry: be·ta–am·y·loid
Variant: also β–amyloid /-'am-&-"loid/
Function: noun
: an amyloid that is derived from a larger precursor protein and is a component of the neurofibrillary tangles and plaques characteristic of Alzheimer's disease called also amyloid beta-protein, beta-amyloid protein

Molecular "Piggyback Ride" Carries Alzheimer's Protein Into Brain, URMC News Next Article
Excerpts: The new findings center on amyloid beta, a tiny protein molecule that accumulates over time to form tell-tale plaques in the brain tissue of Alzheimer's patients. While various cells within the brain itself produce amyloid beta, that amount may be just the tip of the iceberg. Mounting evidence suggests that the bulk of amyloid beta is produced in cells throughout the body and gets circulated in the blood. The new study reveals for the first time how the protein gets from the blood into the brain, thwarting the brain's elaborate filtration mechanism that normally keeps away toxins. (...) "For more than a decade we've known that this protein wreaks havoc in the brains of Alzheimer's patients, but we haven't known how it gets there or how to prevent it from getting there. This study answers both of those basic questions, and opens an entirely new avenue for the treatment of Alzheimer's disease," said lead author Berislav Zlokovic, M.D., Ph.D., of the University of Rochester Medical Center.(...) The blood-brain barrier blocks the passage of toxins while allowing the flow of oxygen, sugar, and other nutrients to brain cells. In the current study, Zlokovic and his colleagues found that amyloid beta protein molecules cannot flow through the blood-brain barrier unaided. Rather, they get through by riding piggyback on a much larger molecule, called RAGE, which is nontoxic and moves unfettered across the blood-brain barrier. Normally, RAGE is produced in small amounts by the cells that form the blood-brain barrier. But in mice that were genetically engineered to develop Alzheimer's disease, Zlokovic found that RAGE was produced in huge amounts - eight times normal - and ferried an avalanche of amyloid beta into the brain.