Study leader Jack Jhamandas of the University of Alberta and his team demonstrated last year a diabetes drug that never made it to market, known as AC253, could block the toxic effects of amyloid protein that lead to brain-cell death.
In the lab, Jhamandas and colleagues including Ryoichi Kimura, a visiting scientist from Japan, tested the memory of normal brain cells and those with Alzheimer's -- both from animal models.
When the drug AC253 was given to brain cells with Alzheimer's and the shock memory tests were redone, memory was restored to levels similar to those in normal cells, Jhamandas said.
"This is very important because it tells us that drugs like this might be able to restore memory, even after Alzheimer's disease may have set in," Jhamandas said in a statement.
Jhamandas said their research tests would take a least a year to complete. He noted it is difficult for AC253 to cross the brain barrier, so research teams in pharmaceutical companies would need to design a similar drug that can penetrate brain cells more easily.
If the tests are successful, Jhamandas said clinical trials could start within about five years.
"I think what we discovered may be part of the solution, but I can't say it will be the solution. There is a long list of drugs and approaches that haven't panned out as expected in the fight against Alzheimer's," Jhamandas said.
"I don't think one drug or approach will solve Alzheimer's disease because it's a complicated disease, but I am cautiously optimistic about our discovery and its implications."
The findings were published in The Journal of Neuroscience.