[ExI] Infection Defense May Spur Alzheimer’s

[Dave Sill]

http://www.nytimes.com/2010/03/09/health/09alzh.html

"For years, a prevailing theory has been that one of the chief
villains in Alzheimer’s disease has no real function other than as a
waste product that the brain never properly disposed of.

The material, a protein called beta amyloid, or A-beta, piles up into
tough plaques that destroy signals between nerves. When that happens,
people lose their memory, their personality changes and they stop
recognizing friends and family.

But now researchers at Harvard suggest that the protein has a real and
unexpected function — it may be part of the brain’s normal defenses
against invading bacteria and other microbes."

...

"But does that mean Alzheimer’s disease is caused by an overly
exuberant brain response to an infection?

That’s one possible reason, along with responses to injuries and
inflammation and the effects of genes that cause A-beta levels to be
higher than normal, Dr. Tanzi said. However, some researchers say that
all the pieces of the A-beta innate immune systems hypothesis are not
in place."

-Dave