By Elaine Cassel
Can head injuries lead to Alzheimer’s disease? Recent research at the University of Pennsylvania School of Medicine offers new clues to the origins of this devastating disorder. Researchers have long known that there is a relationship between deposits (known as plaques) of beta-amyloid protein found between neurons and Alzheimer’s disease. By creating mice with mutated human genes, scientists are learning more about the nature of that relationship.
Researchers at the University of Pennsylvania School of Medicine found direct evidence that mild repetitive head injuries can increase the formation of the plaque-like deposits of beta-amyloid protein in laboratory mice. They inserted a mutated form of the human gene that produces beta-amyloid protein into mice so that the mouse cells would cause deposits of beta-amyloid like those seen in Alzheimer’s patients. Previous research had shown that mice with this gene would eventually develop the plaques and evidence symptoms of Alzheimer’s disease. The question was whether repetitive head injury would hasten the onset of symptoms.
Over the course of the study, the mice were sedated and concussions were produced. Measurements at nine and sixteen weeks after injury found increased amyloid deposits. These findings were supported by observable indications of Alzheimer’s disease, including cognitive impairment. The researchers concluded that there is a causal relationship between repetitive head injury and Alzheimer’s.
The research further elucidates the mechanism of how amyloid plaques form. This knowledge may help lead to a treatment for a disorder that affects millions of Americans, eventually robbing them of virtually all cognitive capacities and physical control and requiring fulltime medical care.
The research was funded by the National Institute on Aging and is reported in January 15, 2002 issue of The Journal of Neuroscience. The abstract of the research is available at: http://www.jneurosci.org/cgi/content/abstract/22/2/515
Elaine Cassel, Marymount University and Lord Fairfax Community College