Great News! Alzheimer's breakthrough hailed as 'turning point'

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117. Beta amyloid...

and tau protein are always found in Alzheimer's Disease (AD) patients. Beta amyloid is only seen in AD patients but tau protein is found in several types of dementia. One of the major hypotheses in this country is a defective enzyme, BACE 1, cleaves the beta amyloid off the amyloid precursor protein. The beta amyloid protein builds up in the brain as plaques. At some point there is a cascade affect and tau protein production starts. A current hypothesis is beta amyloid production triggers tau protein production but beta amyloid production is always first in AD with subsequent tau protein production. After beta amyloid and tau protein production the clinical affects of AD become apparent. Beta amyloid is extracellular and tau protein is intracellular. Both are toxic to nerve cells but tau protein seems to be more toxic.

Up until recently the only way to definitively diagnosis Alzheimer's Disease was via autopsy but there are several radiolabeled PET imaging compounds that have affinity for beta amyloid and are now being used. Currently these imaging compounds are not approved by the FDA but are being used in clinical trials with the anticipation of getting FDA approval down the line. The down side to the imaging compounds is someone who is injected with the compound gets about 2 years worth of radiation and the compounds have to be used within hours of its production which makes it very expensive. The upside is there is a definitive diagnosis of AD if beta amyloid is present.

It is too bad that most people really don't know the basics of AD. If they did the discussions would be more robust.