Researchers report that Alzheimer's disease, which gradually robs millions of sufferers of their memories, may be caused by a failure of the brain's natural ability to clean house as it ages.
Reporting in the journal Science, the researchers said their study marks the first identification of a genetic link between aging and the onset of Alzheimer's disease, which strikes more than one in 30 Americans.
Professor Jeffery Kelly of Scripps Research and Professor Andrew Dillin of the Salk Institute's Molecular and Cell Biology Laboratory made their discoveries studying a roundworm called c elegans – a widely used animal model.
The study found that toxicity from protein aggregation, which appears to cause Alzheimer's, is "drastically reduced" when aging is slowed by modulating the insulin growth factor (IGF) signaling pathway.
Moreover, the researchers found two novel independent activities promoting this cellular survival. The first protective mechanism disassembles and cuts up protein aggregates. Surprisingly, the second protective mechanism enables the formation of larger aggregates from smaller ones that appear to be more toxic.
"The hope is that, by manipulating the protective mechanism inherent in cells, we can find a single entity -- a single drug-that would be useful for a variety of neurodegenerative diseases where protein aggregation leads to neurodegeneration," Kelly said.
