Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=214421
Story Retrieval Date: 5/19/2013 12:35:46 AM CST
Courtesy of David Geffen School of Medicine at UCLA
An abnormal brain protein associated with concussions, called the tau protein, has been imaged in five retired professional football players, UCLA researchers reported Tuesday. It is the first time the protein has been imaged in former players who are still living.
If the results of the preliminary study, published in the American Journal of Geriatric Psychiatry, can be duplicated, the method could lead to early diagnosis of chronic traumatic encephalopathy - a progressive, degenerative brain disease commonly referred to as CTE that can be caused by mild repetitive brain injuries. It would be a critical step in developing interventions that could prevent the onset and progression of symptoms.
“This offers us an opportunity, not only to help professional athletes, but amateur players, kids in school, military personnel, motor vehicle accident victims,” said lead author Dr. Gary Small, a professor of psychiatry and biobehavioral sciences at the Semel Institute for Neuroscience and Human Behavior at UCLA. “We can identify candidates for preventive measures.”
Mild traumatic brain injuries can cause chronic behavioral, mood and cognitive instabilities associated with a buildup of tau protein. Currently, a deposit of the protein in this setting can only be identified in a brain autopsy.
“It’s the first time we’ve done these kinds of scans in professional athletes,” Small said. And the results “were identical to autopsies.”
The study looked at five retired football players between the ages of 45 and 73 years old who played between 10 and 16 years in the National Football League, and five male controls of comparable age, education, and body mass index. The retired players represented a variety of positions: quarterback, linebacker, guard, defensive lineman and center. Each player had a history of mood and cognitive symptoms.
The subjects received injections of a chemical marker called FDDNP and then underwent PET scans. FDDNP is a marker created by the research group that attaches to amyloid beta “plaques” and neurofibrillary tau “tangles” in the brain. According to Small, because FDDNP is slightly radioactive, the PET scan can detect the tau proteins by picking up on the radiation.
“One of the challenges in this kind of science is creating a molecule that passes through the blood/brain barrier,” he said.
After the scans, the retired player images were compared to the control images. FDDNP levels of players were significantly higher than those of controls. Additionally, a link between history of head injuries and FDDNP binding was suggested by observed pattern of higher binding in those that had suffered a greater number of concussions in their career.
Though the study was limited by its small size, elevated amygdala and subcortical FDDNP binding patterns in players were consistent with patterns of tau deposition observed in autopsies of CTE cases. CTE is characterized by mood, personality, cognitive and behavioral changes as well as some motor symptoms such as tremors and abnormal gait. It is associated with widespread buildup of tau proteins and currently can only be diagnosed in former football players at autopsy.
According to co-author Dr. Julian Bailes, chairman of the Department of Neurosurgery at NorthShore University HealthSystem, CTE victims tend to suddenly commit suicide. Only at autopsy is their condition discovered.
“People with CTE aren’t diagnosed until they’re in the grave,” Bailes said. “If we had a way to intervene, we might have the ability to treat them.”
The application wouldn’t be limited to professional athletes. Mary Wisniewski, head athletic trainer at the University of Chicago, said that the study was “interesting” and “very applicable” to the work that the trainers do at the university with college athletes.
She said that they would definitely be following the progression of further research. If the results are confirmed in the future, “obviously we would apply it to our protocol,” Wisniewski said.
However, the limited size and preliminary nature of the study means that it is too soon to draw conclusions from the date.
“This is a pilot study,” Bailes said. “It’s preliminary data … but it’s unique in its findings.”
Small expressed a similar opinion.
“We need a larger study. We’ve already applied for grants.”
The larger study would follow patients to the point of autopsy, which would allow for scientists to confirm the accuracy of the PET images, three-dimensional images of the brain created by the PET scan after the FDDNP injection.
Small hopes that the findings of the preliminary studies will lead to preventive measures, even before final results come in.
“I don’t think football’s going away, so there’s a lot we can do to make it safer.”