Mice bred to produce defective tau protein develop memory loss. Turning off defective protein production aids memory recovery -- but the brain continues to form neurofibrillary plaques and tangles.
Ashe said the new findings suggest that abnormal forms of the proteins work like poisons. They might be disrupting the function of brain cells early in the disease process, and long before the plaques and tangles appear. The plaques and tangles might, instead, be a defensive mechanism to neutralize the bad proteins, she said.This has been a recurring idea for some years -- that the "pathologic structures" seen in brains afflicted by the Alzheimer's process are actually attempts to protect the neuron. Dr. Ashe's research has greatly strengthened that hypothesis. Now others will have to validate these results.
Update: Thinking this over, it occurs to me that the plaques and/or tangles would still play a pathologic role if they somehow acted with the tau protein to cause memory loss. Oh well, Dr. Ashe probably has other reasons to suspect they're protective.