Tau Imaging of Chronic Traumatic Encephalopathy

Summary

Chronic traumatic encephalopathy (CTE) is a progressive degenerative brain disease with symptoms that include memory loss, problems with impulse control, and depression that can lead to suicide. As the disease progresses, it can lead to dementia. Currently CTE can only be diagnosed postmortem where an over-accumulation of a protein called tau is observed. There is now a new experimental measure that makes it possible, for the first time, to measure tau protein in the living human brain using a novel positron emission tomography (PET) ligand, \[F-18\] AV-1451 (aka, \[18F\]-T807).

The main objective of this study is to use a novel PET approach to measure tau accumulation in the brain. The presence of CTE at autopsy in deceased National Football League (NFL) players has been well documented. Accordingly, we will conduct this study in a group of retired NFL players who have clinical symptoms of CTE and are suspected of having CTE based on high levels of tau in their spinal fluid and abnormalities seen on research brain scans. We will compare them with a control group of former elite level athletes who have not experienced any brain trauma, deny any clinical symptoms, and who have completely normal spinal fluid tau and amyloid levels, and brain scans. We will also include a group of subjects with AD. All participants will be recruited from ongoing studies, headed by the Partnering PI of this proposal, Dr. Robert Stern, at the Boston University Center for the Study of Traumatic Encephalopathy and the Alzheimer's Disease Center. We will use both a beta amyloid PET scan (\[18F\]-florbetapir) and a tau PET scan (\[18F\]-T807) on consecutive days. With the beta amyloid scan we expect little or no evidence of amyloid in the NFL players with presumed CTE, and no evidence of amyloid in the control group of athletes with no history of repetitive brain trauma. In contrast we expect to see beta amyloid accumulation in the AD patient brains. With the new tau ligand, we expect that the NFL players with presumed CTE will show elevated levels of tau protein in the brain, which will not be observed in athletes without a history of brain trauma, but which will be seen in the AD patients' brains.

Another goal is to use the latest MRI technologies to develop specific tau imaging biomarkers that correlate with the PET and spinal fluid tau measures but without the radiation of PET or invasiveness of spinal taps. The development of these surrogate imaging markers of tau, is critically important to diagnosing CTE. This in turn will lead to studies relevant to treatment and prevention of this devastating disease. Finally, as an exploratory method of examining possible genetic risk for CTE, we will also use cutting edge genetic analysis of blood samples from subjects in this proposal and compare tau load, measured by PET tau ligand uptake and cerebrospinal fluid (CSF) p-tau level, with a measure of genetic susceptibility to tau load, referred to as the genetic risk score for tau.

Conditions

• Chronic Traumatic Encephalopathy

Interventions

RADIATION

[F18]-T807

\[F18\]-T807 PET Scan to measure tau deposition in the brain.

RADIATION

[F18]-Florbetapir

\[F18\]-Florbetapir PET scan to measure Beta-amyloid deposition in the brain.

DEVICE

MRI/MRS

Two scans (structural, diffusion tensor imaging, and susceptibility weighted imaging scanned as part of one MR protocol, and a one-dimensional and two-dimensional spectroscopy examination as part of the other MR protocol.

GENETIC

Genetic Analysis for Genetic Risk Score for Tau.

DNA will be extracted from previously acquired and de-identified frozen blood specimens using a standard protocol (Gentra Puregene Kit, Qiagen 158422). Genotyping will be performed using the iPLEX Sequenom MassARRAY platform and samples will be genotyped for single nucleotide polymorphisms (SNPs) associated with the deposition of neurofibrillary tangles.

Sponsors & Collaborators

• U.S. Army Medical Research and Development Command

  collaborator FED

• Boston University

  collaborator OTHER

• Brigham and Women's Hospital

  lead OTHER

Principal Investigators

• Martha E. Shenton, Ph.D. · Brigham and Women's Hospital

Study Design

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

40 Years

Max Age

69 Years

Sex

MALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2015-01-31

Primary Completion

2016-09-30

Completion

2016-09-30

Countries

• United States

Study Locations