Public Release: 

Experimental PET scan detects abnormal tau protein in brains of living former NFL players

Boston University School of Medicine

(Boston)--Using an experimental positron emission tomography (PET) scan, researchers have found elevated amounts of abnormal tau protein in brain regions affected by chronic traumatic encephalopathy (CTE) in a small group of living former National Football League (NFL) players with cognitive, mood and behavior symptoms. The study was published online in the New England Journal of Medicine.

The researchers also found the more years of tackle football played (across all levels of play), the higher the tau protein levels detected by the PET scan. However, there was no relationship between the tau PET levels and cognitive test performance or severity of mood and behavior symptoms.

"The results of this study provide initial support for the flortaucipir PET scan to detect abnormal tau from CTE during life. However, we're not there yet," cautioned corresponding author Robert Stern, PhD, professor of neurology, neurosurgery and anatomy and neurobiology at Boston University School of Medicine (BUSM). "These results do not mean that we can now diagnose CTE during life or that this experimental test is ready for use in the clinic."

CTE is a neurodegenerative disease that has been associated with a history of repetitive head impacts, including those that may or may not be associated with concussion symptoms in American football players. At this time, CTE can only be diagnosed after death by a neuropathological examination, with the hallmark findings of the build-up of an abnormal form of tau protein in a specific pattern in the brain. Like Alzheimer's disease (AD), CTE has been suggested to be associated with a progressive loss of brain cells. In contrast to AD, the diagnosis of CTE is based in part on the pattern of tau deposition and a relative lack of amyloid plaques.

The study was conducted in Boston and Arizona by a multidisciplinary group of researchers from BUSM, Banner Alzheimer's Institute, Mayo Clinic Arizona, Brigham and Women's Hospital and Avid Radiopharmaceuticals. Experimental flortaucipir PET scans were used to assess tau deposition and FDA-approved florbetapir PET scans were used to assess amyloid plaque deposition in the brains of 26 living former NFL players with cognitive, mood, and behavior symptoms (ages 40-69) and a control group of 31 same-age men without symptoms or history of traumatic brain injury. Results showed that the tau PET levels were significantly higher in the former NFL group than in the controls, and the tau was seen in the areas of the brain which have been shown to be affected in post-mortem cases of neuropathologically diagnosed CTE.

Interestingly, the former player and control groups did not differ in their amyloid PET measurements. Indeed, only one former player had amyloid PET measurements comparable to those seen in Alzheimer's disease.

"Our findings suggest that mild cognitive, emotional, and behavioral symptoms observed in athletes with a history of repetitive impacts are not attributable to AD, and they provide a foundation for additional research studies to advance the scientific understanding, diagnosis, treatment, and prevention of CTE in living persons, said co-author, Eric Reiman, MD, Executive Director of Banner Alzheimer's Institute in Phoenix, Arizona. "More research is needed to draw firm conclusions, and contact sports athletes, their families, and other stakeholders are waiting.

With support from NIH, the authors are working with additional researchers to conduct a longitudinal study called the DIAGNOSE CTE Research Project in former NFL players, former college football players, and persons without a history of contact sports play to help address these and other important questions. Initial results of that study are expected in early 2020.

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Funding for this study was provided by grants from Avid Radiopharmaceuticals (a wholly-owned subsidiary of Eli Lilly and Company), the National Institutes of Health (grant numbers R01NS078337, U19AG024904, 1UL1TR001430); the State of Arizona; and the US Department of Defense (grant numbers W81XWH-13-2-0063, W81XWH-13-2-0064, W81XWH-14-1-0462). All flortaucipir and florbetapir PET radiotracers were provided by Avid Radiopharmaceuticals.

About Boston University School of Medicine

Originally established in 1848 as the New England Female Medical College, and incorporated into Boston University in 1873, Boston University School of Medicine (BUSM) today is a leading academic medical center with an enrollment of more than 700 medical students and 950 students pursuing degrees in graduate medical sciences. BUSM faculty contribute to more than 950 active grants and contracts, with total anticipated awards valued at more than $693 million in amyloidosis, arthritis, cardiovascular disease, cancer, infectious diseases, pulmonary disease and dermatology, among other areas. The School's teaching affiliates include Boston Medical Center, its primary teaching hospital, the Boston VA Healthcare System, Kaiser Permanente in northern California, as well as Boston HealthNet, a network of 15 community health centers. For more information, please visit http://www.bumc.bu.edu/busm/

About Banner Alzheimer's Institute

Through its research and care, Banner Alzheimer's Institute is dedicated to the goal of ending Alzheimer's disease without losing another generation. Founded in 2006 by Banner Health, one of the country's largest nonprofit health care systems, BAI has a three-fold focus: to conduct revolutionary studies in the detection, treatment and prevention of Alzheimer's; to set a national standard of patient and family care; and to forge scientific collaborations that bring together institutions and disciplines internationally. For more information visit http://www.banneralz.org; or to support our programs and services go to give.bannerhealth.com/Alzheimers.

About Mayo Clinic

Mayo Clinic is a nonprofit organization committed to clinical practice, education and research, providing expert, comprehensive care to everyone who needs healing. Learn more about Mayo Clinic. Visit the Mayo Clinic News Network.

About Brigham Health

Brigham Health, a global leader in creating a healthier world, consists of Brigham and Women's Hospital, Brigham and Women's Faulkner Hospital, the Brigham and Women's Physicians Organization and many related facilities and programs. With more than 1,000 inpatient beds, approximately 60,000 inpatient stays and 1.7 million outpatient encounters annually, Brigham Health's 1,200 physicians provide expert care in virtually every medical and surgical specialty to patients locally, regionally and around the world. An international leader in basic, clinical and translational research, Brigham Health has nearly 5,000 scientists, including physician-investigators, renowned biomedical researchers and faculty supported by over $700 million in funding. The Brigham's medical preeminence dates back to 1832, and now, with 19,000 employees, that rich history is the foundation for its commitment to research, innovation, and community. Boston-based Brigham and Women's Hospital is a teaching affiliate of Harvard Medical School and dedicated to educating and training the next generation of health care professionals. For more information, resources, and to follow us on social media, please visit brighamandwomens.org.

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