Researchers
at Mount Sinai used a novel experimental imaging agent called [18
F]-T807 (or Avid 1451) with PET scan to visualize the
of a living,
39-year-old retired National Football League (NFL) player who had previously
suffered 22 concussion injuries, and displayed clinical features consistent
with
, a
neurodegenerative brain disease that has been linked to suffering repetitive
trauma or blows to the head in athletes and soldiers.
‘New imaging agent may become a diagnostic biomarker for detection of chronic traumatic encephalopathy (CTE).’
The
PET
tracer has been designed and modified to attach to a protein called 'tau'
that gets deposited in the brain as a result of concussion injury. In a person
suffering from CTE,
the tracer lights up
areas of the brain showing a distinctive pattern of 'tau' protein accumulation.
Until now, evidence for CTE pathology has only been possible by examining brain
tissue after death.
Distinctive Pattern
of Tau Protein Accumulation In CTE
CTE shows a distinctive pattern of tau
protein accumulation that was described in 2015 by an expert panel commissioned
by the National Institute of Neurological Disorders and Stroke (NINDS). The
diagnostic criteria of CTE were arrived by the panel, based on examination of
brain tissue samples following death.
The surface of the brain is highly wrinkled.
The 'tau' protein accumulation in CTE
follows the highly folded surface of the brain and is especially highest at the
deepest points in the wrinkles and folds. The NINDS panel described this
distinctive pattern as
'pathognomonic'
of CTE. The term 'pathognomonic' indicates that if this pattern of tau protein
accumulation is seen in the brain, the diagnosis can only be CTE. There should
be no confusion with other tau diseases such as
Alzheimer's.
Potential
Applications For The New Tracer
- If further tests prove the efficacy of T-807 in outlining the
distinctive pattern of tau protein deposition in CTE, it could well become a
diagnostic marker for the ante-mortem diagnosis of CTE.
"Our
study participant's scan is the first to reveal during life a pattern of tau
imaging that outlines the wrinkles and folds of the living brain, just like the
'pathognomonic pattern' described by the NINDS panel as diagnostic of a brain
with CTE," says Sam Gandy, MD, Director of the Center for Cognitive Health and
NFL Neurological Care Program at the Icahn School of Medicine at Mount Sinai
and last author of the study. "When fully validated, this new ligand has the
potential to be used as a diagnostic biomarker and represents an exciting
development in the detection and tracking of CTE." - PET
scans using the new tracer may help to study the pathology and disease course
of CTE.
"This research is in its infancy," says Dara L.
Dickstein, PhD, Assistant Professor of Neuroscience, and Geriatrics and
Palliative Medicine at the Icahn School of Medicine at Mount Sinai and first
author of the study. "Whether or not the pathology can be reversed or halted is
something we have yet to determine and these new tauopathy PET scans may be able to help in this
endeavor."
Future Research
Plans Using The Tracer
The Mount Sinai team of researchers is
currently studying 24 patients and
plans
to begin a clinical trial early next year using the new ligand to identify CTE
patients who might respond to an anti-tauopathy medicine that is currently
being tested at other medical centers for the treatment of Alzheimer's disease
and other neurodegenerative disorders.
"The findings demonstrate that we may now
have the first biomarker for the detection of CTE through tau imaging," says
Howard Fillit, MD, Alzheimer's Drug Discovery Foundation's (ADDF) Founding
Executive Director and Chief Science Officer. "This may prove significant as an
early diagnostic tool for those who suffer repeated traumatic brain injuries.
It may also help us better understand the similarities in disease processes
between CTE, Alzheimer's and other neurodegenerative diseases, and determine
whether repeated
head injuries may
lead to the onset of Alzheimer's."
About Chronic
Traumatic Encephalopathy
Chronic traumatic encephalopathy is a
progressive degenerative disease of the brain due to repeated trauma to the
brain. It typically occurs in sportspersons and soldiers. Repeated trauma
causes accumulation of an abnormal type of a protein called 'tau'. Build-up of
the tau protein causes the death of nerve cells.
Features of CTE
include loss of memory and confusion, impaired reasoning and judgment,
paranoia, impulsive behavior, mood swings, violence, depression, and ultimately
leading to progressive dementia. Interestingly, symptoms may appear months,
years, or even decades after occurrence of trauma. At present, CTE can be
definitively diagnosed only after death by examination of brain tissue.
CTE can be prevented
by avoiding brain trauma and preventing additional injury after a concussion.
In the sports field, incidence of concussion may be reduced by wearing
protective helmets, which however don't totally eliminate the risk. Coaches and
players should be aware of signs and symptoms of concussion.
It has also been
recommended that motorcyclists and other two wheeler riders wear helmets to
protect against head injury and consequent
brain damage.
References
- Chronic Traumatic Encephalopathy -
(http://www.mayoclinic.org/diseases-conditions/chronic-traumatic-encephalopathy/basics/prevention/con-20113581)
- What is CTE? - (http://concussionfoundation.org/learning-center/what-is-cte)
Source: Medindia
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