Source : http://news.bbc.co.uk
June 08, 2009 - Alzheimer's disease is the leading cause of neurodegenerative damages and is the most common form of dementia associated with age.
A European team has just discovered one of its possible causes could be infectious, but not caused by any pathogen.
Neuroimaging techniques allowed to find that the damages to the brain caused by the Alzheimer's disease can be caused by two different proteins: the "beta-amyloid" which forms plaques in the brain that affect neurons and synapses and the "tau" protein which create tangles (abnormal filamentous assemblies) that produce nerve cell degeneration.
Both mechanisms share properties that remind of another neurodegenerative disease: the New Variant of Creutzfeldt-Jakob Disease (vCJD), the human version of the "mad cow" disease. A team of scientists from the Universities of Basle (Switzerland), Cambridge (United Kingdom) and Tübingen (Germany) have just published their findings in Nature Cell, showing that the "rogue form" of the tau protein can spread in the brain exactly as the prions that cause the vCJD.
The test is apparently simple: they took a mouse with the murine variant of Alzheimer's, extracted tau tangles from brain cells and injected them to healthy animals: shortly after, the healthy mice developed the disease, highlighting a mechanism very similar to prions (also a type of protein) that cause the Creutzfeldt-Jakob disease.
The relationship between prion proteins and Alzheimer's disease opens new doors for experimentation. To quote Michel Goedert, one of the researchers in Cambridge, "it does not mean that Alzheimer's is contagious" (to infect mice, it requires a protein to be injected in the mice's brain, which does never occur in nature), but it allows a deeper knowledge of the mechanisms of the disease, and new possibilities for treatment.Read full article »