Researchers reverse memory loss in mice
By Jeff Hansel
A new University of Minnesota and Mayo Clinic study was able to reverse memory loss in mice.
That opens doors to new research. Scientists involved say human treatments will not be developed from this research for up to five to 10 years.
The results from the study were so different than expected, researchers were convinced they were wrong.
Dr. Karen Ashe, a neurologist at the University of Minnesota, jots notes about her research memory and dementia in a journal at night.
After one disappointing day, her entry went something like this: Had a really bad day at work. Experiments aren't working as expected. Something's wrong. We're going to have to figure out what it is.
But the results were correct.
"We repeated the experiment once, and then we repeated it again, and we kept getting the same results," she said Friday, the day that the journal Science published the results of what turned out to be a dramatic study.
Ashe and researchers from Mayo Clinic in Jacksonville, Fla., and Massachusetts General Hospital investigate Alzheimer's-like conditions causing dementia in mice. They purposely gave mice a human "transgene" called "tau." It causes dementia.
Mice swam in water to learn where a platform was located. With tau turned on, they forgot where the platform was. With it off again, mice that swam around aimlessly remembered where the platform had been before and swam to the location.
The mice with dementia also developed tangles in their brains, a hallmark Alzheimer's. Scientists long assumed tangles cause Alzheimer's. When the tau was turned off, tangles continued to grow in the mice brains, but mouse memory came back.
"We said, well, maybe -- maybe -- the tangles aren't responsible for the memory problems. Maybe it's some other form of tau," Ashe said. Now, she said, researchers want to know what that intermediary before the tangles is.
Researchers understand such studies are stepping stones to developing treatments, and they feel the importance of that task.
"Because my family has been affected, I understand the hardships and the life-altering hardships that you go through dealing with this disease," said Mayo Clinic neuroscientist Jada Lewis.
Dr. Sam Gandy, chairman of the Alzheimer's Association Medical and Scientific Advisory Board, said studies in mice do not translate into human treatment, but the study "points us to a new target."
People already disabled by dementia won't be helped by the discoveries, he said. But the idea that, in the future, some memory loss might be reversible is intriguing.
Ashe said people should not expect new treatments from this study for five to 10 years.
"There are many more steps involved. We still have to understand the steps of this process in mice," she said.
Scientists thought people with Alzheimer's and other dementia lose memory because neurons died. But in mice, Ashe said, it appears that, although many neurons die, many simply malfunction and could work again if a treatment were found.
"The malfunctions are a source of tremendous potential if we can get those malfunctioning neurons to function again, and that's a source of hope," Ashe said.