A study reported in the Journal Nature identifies a substance in the brain that has been shown to cause the memory loss associated with dementia and Alzheimer's disease.
It is generally accepted that Alzheimer's is caused by naturally-occurring proteins that build up into plaque between nerve cells in the brain.
Study co-author and Michela Gallagher with Johns Hopkins University says researchers hypothesized that a form of the protein, called amyloid beta, was the culprit.
"Certain soluble versions of this protein that might be floating around the brain -- interacting with the physiology of the brain rather than (being) deposited in these plaque reservoirs -- could be messing up how the brain functions. And that could be causing problems with memory, some of the early clinical symptoms of the disease.
Researchers at the University of Minnesota genetically engineered mice to develop Alzheimer's-like memory loss and then isolated and extracted the amyloid beta protein and sent it to Gallagher's lab at Johns Hopkins University for further analysis.
"And we administered minute quantities of this protein into otherwise healthy, normal young animals. And we found that when very small quantities of this protein were administered so that it had access to the brain it caused memory impairment in these otherwise healthy young animals."
While this form of protein may be causing memory loss in the early stages of the disease, Gallagher says researchers want to better understand its connection to the brain's degeneration over time.
"So, in other words, if you could find a way to interrupt the beta amyloid that in our work caused a memory problem, could you also interrupt the cascade that leads to degeneration. So you would both symptomatically treat the disease and also prevent its progression."
Gallagher says Alzheimer's disease causes irreversible damage and the earlier the treatment the better. She says understanding how amyloid beta works is an important first step in treating the disease that afflicts 12 million people worldwide and is the leading cause of dementia among the elderly.
