Alzheimer's disease affects an estimated 27 million people worldwide and is the most common form of age-related dementia, researchers said. There is no cure and available drugs only help to relieve symptoms.
One problem in rapidly screening potentially useful drugs has been the lack of a good model system in which Alzheimer's plaques and tangles appear quickly.
But in the study, scientists Mike Virata and Bob Zeller at San Diego State University say they've found the sea squirt (Ciona intestinalis) -- in their immature, tadpole form -- resemble proper vertebrates, and they share about 80 percent of their genes with humans.
The researchers reported dosing sea squirt tadpoles with a mutant protein found in humans with hereditary Alzheimer's resulted in aggressive development of plaques in the tadpoles' brains in only a day, and those, along with the accompanying behavioral defects seen in the tadpoles, could be reversed by treating with an experimental anti-plaque forming drug.
Virata and Zeller said their findings represent an important breakthrough, since all other invertebrates tested have been unable to process the plaque-forming protein, and vertebrates take months or years to make plaques.
The study is reported in the journal Disease Models & Mechanisms.