Repeated Injury Hastens Alzheimer's

From the WebMD Archives

Jan. 18, 2002 -- Researchers have found the first direct evidence that repetitive head injuries -- even mild -- can accelerate the onset of Alzheimer's disease. The study, done in mice, brings us one step closer to actually curing the brain degeneration, one researcher says.

"This is the first experimental evidence linking head injuries to Alzheimer's disease by showing how repetitive concussion can speed up the progress of the disease," said researcher Kunihiro Uryo, PhD, in a news release. Uryo is senior research investigator at the University of Pennsylvania School of Medicine's Center for Neurodegenerative Disease Research (CNDR).

This research builds on a previous study that WebMD reported last fall. In that study, also in mice, researchers found that having two concussions within 24 hours produced lasting nerve damage. In addition, mice with two brain injuries had an accumulation of a protein in their brain called beta-amyloid precursor protein, -- the same substance suspected to be at work in Alzheimer's disease. They suggested that the buildup of this protein in the brain may have choked off and killed the nerve cells.

In this new study, mice that were genetically bred to develop Alzheimer's disease were sedated and given mild repetitive concussions. Over the next few weeks, the researchers saw a buildup of the beta-amyloid protein. The repetitive head injury accelerated the rate of the brain disease. However, this faster accumulation was not seen in mice that sustained just a single brain injury.

"Here we can clearly see a direct cause-and-effect relationship between repetitive concussions and Alzheimer's," said senior researcher of the study John Q. Trojanowski, MD, PhD, in a news release. He is co-director of the CNDR and professor in the department of pathology and laboratory medicine.

He also says that this and further research will allow the development of treatments for Alzheimer's that get right to the cause of the disease. Current treatments are not able to do this and only treat the symptoms.

"Alzheimer's disease has a very real and understandable molecular basis and it will be curable," said Trojanowski. "[This] is just one more step in reaching the inevitable treatment."