Alzheimer's Traced to Proteins Caused by Ageing 

The irreversible brain disorder Alzheimer's Disease may be caused by inflammatory processes associated with aging and not - as generally believed - by plaque-like deposits in the brain, researchers said. 

The scientists from the University of Southern California in Los Angeles and Northwestern University in Evanston, III., said their findings could open new avenues for exploring ways to treat or even cure the disease. 

Their findings, published this week in the journal "Trends in Neurosciences," still lays the blame for Alzheimer's on a molecule called amyloid beta, but traces the basic cause of the disease to the formation of toxic proteins rather than the build-up of plaque and tangles inside nerve cells in the brain. 

Alzheimer's starts with memory loss and progresses to profound dementia and death. There is no cure, although a there are a few drugs that provide temporary relief for some symptoms of the disease. 

"We were able to identify in laboratory test tubes a new kind of toxic activity that is implicated as a root cause of Alzheimer's," Dr. Caleb Finch, director of the Neurogerontology Division at the USC Andrus Center's Gerontology Research Institute, said. 

The researchers discovered a novel form of wadded-up amyloid called "amyloid b-derived diffusible ligands" - ADDLs or "addles" for short - that form in the presence of certain inflammatory proteins in the brain. They have chemical and toxicological properties quite different from either single beta-amyloid molecules or clumps of the molecules called fibrils.  

For nearly two decades, Alzheimer's research has focused on ways to prevent the formation of fibrils, which coalesce into even larger deposits in the brain known as plaques, which have been shown to kill nerve cells in the brain.  

Source : Pharmabiz, April 26, 2001