Is Alzheimer's Damage Reversible?

Posted on July 16, 2005

A study conducted on mice suggests that damage caused by Alzheimer's may be reversible -- at least in mice. Reuters reports that mice were able to regenerate neurons in the experiment after a gene was switched off.

Outward symptoms start with memory loss, which progresses to complete helplessness as brain cells are destroyed. In the brain, neurons die as messy plaques and tangles of protein form.

The two proteins involved are unhealthy forms of natural brain compounds called amyloid beta and tau protein.

Ashe's team worked with mice genetically engineered to develop the mutant tau, but this mutation could be stopped - or de-activated - with use of a drug called doxycycline.

As expected, the mice developed dementia and had brain atrophy similar to human Alzheimer's disease.

And when the engineered gene was turned off, memory loss stopped, as expected. But the mice did not merely stop getting worse. They got better.

"Even mice that had lost half the neurons that are involved in forming memories, when we removed the molecule causing the memory loss from the remaining neurons by turning off the genes, the mice were able to learn and remember new information," Ashe said in a telephone interview.

"No one suspected so many neurons would still be able to function."

Alzheimer's is expected to inflict over 16 million people by 2015 in the U.S. alone so it is hopeful to know that there may be a way to stop and even reverse the damage. Karen Ashe, the Alzheimer's researcher at the University of Minnesota, told Reuters that she was astonished when she discovered that some of the damage had reversed course in the mice.

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