An international team has discovered what it claims is a link between levels of amyloid-beta protein in blood and the disease, a finding which could provide a new way of combating the devastating effects of the most common form of dementia.

In their study on mice, researchers manipulated the livers of rats to increase blood levels of amyloid-beta. They found that raising A-beta blood levels slowed down the speed at which molecules of the protein swept from the rats' brains.

Dr David Cook of University of Washington, who led the team, said "We knew from previous work that the liver plays an important role in removing A-beta from the blood.

"So, we thought if we temporarily prevented liver- mediated clearance it might be possible to set or 'clamp' peripheral A-beta levels long enough to find out whether A-beta in the blood stream affects A-beta clearance from brain.

"We were a bit surprised to see how effective this strategy was. Peripheral A-beta clearance immediately halted almost completely. For several years, it has been suggested that the circulatory system can act like an A-beta sink. The data clearly show that the liver is the primary drain."

Added co-author Dr Sum Lee of University of Hong Kong:

"The liver influences virtually everything that happens in the body, so it is not far-fetched to imagine that in the future it may be possible to find ways to help brains of Alzheimer's disease patients with their livers."

The findings of the study are published in the latest edition of the 'Journal of Alzheimer's Disease'.

Experts have welcomed this research.

"This new study shows us just how complex Alzheimer's disease is, suggesting the liver could be involved in clearing the toxic protein, amyloid, from the blood, which in turn could help amyloid clearance from the brain.