Study: Repetitive Head Injuries Hasten Development of Alzheimer's

Mild repetitive head injuries can hasten development of Alzheimer's disease, researchers at the University of Pennsylvania School of Medicine have concluded from studies of mice.

Brain trauma appears to accelerate Alzheimer's by increasing the free radical damage and the formation of amyloid beta protein plaque deposits, the researchers reported in the Journal of Neuroscience.

Researchers gave a special breed of mice, which contain the human gene that produces the amyloid beta protein, repetitive concussions and then monitored their behavior and brain pathology, looking for amyloid deposits and amounts of a molecule called isoprostane. Urine isoprostane levels have been shown to indicate the sort of free radical damage found in Alzheimer's disease.

Researchers saw a dramatic increase in these two indicators of Alzheimer's disease in the mice that received repetitive head injuries. Single head injuries did not cause the same response.

"This is the first experimental evidence linking head injuries to Alzheimer's disease by showing how repetitive concussions can speed up the progress of the disease," said Kunihiro Uryu, PhD, senior research investigator at Penn's Center for Neurodegenerative Disease Research (CNDR). "It also shows the tremendous utility of the transgenic mice and the trauma model we have developed for Alzheimer's research."

"Here, we can clearly see a direct cause and effect relationship between repetitive concussions and Alzheimer's," said Dr. John Q. Trojanowski, co-director of the CNDR. "Using the head trauma model in these mice represents a step forward in our ability to understand the basic molecular mechanisms behind Alzheimer's disease. More importantly, we believe this model system can be used to screen for new medications in the search for a cure."

Other sources: University of Pennsylvania School of Medicine