Another amyloid biomarker linked to Alzheimer's

For a while now, scientists have relied on amyloid beta plaque deposits in the brain as a clue to help diagnose Alzheimer's. But a related protein known as amylin also appears to build up in a major way. And researchers think it could eventually serve as another dementia or Alzheimer's biomarker.

A team from the UC Davis Alzheimer's Disease Center made the finding. The Annals of Neurology recently published their study online.

Interestingly, the discovery appears to give doctors a biomarker they can use for patients with Type 2 diabetes, who the researchers note are at high risk, in part, for dementia (and cerebrovascular disease). Patients who suffer from obesity or Type 2 diabetes end up having large amylin deposits in their pancreas, they say. And they believe the finding explains why they appear more likely to develop dementia.

For the study, scientists looked at brain tissue from patients who had diabetes and dementia either because of Alzheimer's or cerebrovascular problems. They also scrutinized brain samples of patients who had Alzheimer's but no diabetes and healthy patients as a point of comparison. Interestingly, brain samples from diabetic patients contained gobs of amylin deposits, as did the brain blood vessels. Alzheimer's patients without diabetes had the same amylin tissue deposits. And not surprisingly, brain samples from otherwise healthy subjects had no amylin.

Additionally, the team discovered that amylin also combined with amyloid beta plaque deposits. They believe this helps confirm amylin as a second amyloid and suggests its potential reliability as a dementia/Alzheimer's biomarker.

"The amylin looks like the amyloid beta protein and they both interact," UC Davis Alzheimer's Disease Center Director Charles DeCarli said in a statement. "That's why we're calling it the second amyloid of Alzheimer's disease."

As these things go, it's an impressive finding. More work is needed, of course. But if further research bears this out, amylin could come in handy as both a diagnostic biomarker and maybe even a new drug target for future treatments, the researchers believe.

- read the journal abstract
- here's the release