Scientists have known for some time that individuals with Alzheimer's disease have a build-up of plaques made of a specific type of proteins (called beta-amyloid proteins) in more than one area of the brain. It has not been clear whether the presence of the proteins actually caused the disease or whether the proteins were simply a result of the disease process.
However, a study published in the June 22, 2008 online edition of Nature Medicine revealed that rats who had these type of proteins introduced into their brains did develop Alzheimer's symptoms, especially difficulty in remembering newly learned behaviors. In addition, when these proteins were introduced to the hippocampus area of mouse brains they seemed to degrade the connections between cells that are needed for communication within the brain. This result points to a cause, rather than effect role of the proteins in disease.
"While more research is needed to replicate and extend these findings, this study has put yet one more piece into place in the puzzle that is Alzheimer's."
Researchers, led by Ganesh M. Shankar, Ph.D., and Dennis J. Selkoe, M.D., of Brigham and Women's Hospital and Harvard Medical School, were also able to deactivate the proteins by introducing antibodies against them into the animal models. While this process will not be applicable to humans any time soon, researchers cite this as a promising development. Richard J Hodes, the Director of the National Institute for Aging, the federal agency that funded the study, explained, "While more research is needed to replicate and extend these findings, this study has put yet one more piece into place in the puzzle that is Alzheimer's."