Beta Amyloid: Friend or Foe?

Contributed by: Dennis Fortier, President, Medical Care Corporation

According to the amyloid hypothesis, an accumulation of this protein in the brain leads to the formation of plaques which eventually kills neurons and causes dementia. It is a popular theory given a fairly high correlation between amyloid load and loss of cognition and given that lowering amyloid load (through a variety of strategies) has been associated with improved cognitive function. This theory is driving a large portion of drug development activity in current FDA trials.

However, there are some troubling aspects to the theory. Notably, there are many well-documented instances of autopsied brains that were full of amyloid plaques but came from the skulls of persons with high cognitive function. Perhaps this can be explained by timing. Perhaps the plaques build, then there is a period of progressive brain damage due to the presence of the amyloid, then cognition declines. It is plausible and would explain why we sometimes find cognitively vital people with lots of amyloid in their brains.

New research from Saint Louis University and published in the online Journal of Alzheimer's Disease suggests a more complex relationship between amyloid and the brain. In a study on mice, researchers demonstrated that amyloid was associated with improved learning and memory, the exact opposite of what might have been expected. This suggests that viewing all amyloid as bad may be too simplistic. Perhaps having either too much or too little is the real problem and therapeutic strategies should be refined to "regulate" amyloid as opposed to "eliminate" this important protein.

Each day we find another answer and pose another question to this complex puzzle but slowly, it is coming together into a more comprehensive understanding of how to treat the disease.

1 comment :

  1. Perhaps the amyloid is a compensation for damage done? Then in the high functioning people with a lot of amyloid in their brains, the amyloid had a protective function. Just a thought.