Mass General finds autism clue
Levels of key protein lacking
The brains of young men with autism have surprisingly low levels of a key protein that plays a role in inflammation and metabolism, researchers at Massachusetts General Hospital found, providing a new look into the possible origins of the condition.
Using cutting-edge imaging technology, the researchers scanned the brains of 15 young adult men with autism of varying levels along with the brains of 18 patients without autism.
The investigators thought the scans would show increased levels of translocator protein (TSPO) in subjects who have autism — but were shocked at the results.
“To our surprise, that’s not what we saw,” said Nicole Zurcher, an investigator in MGH’s Athinoula A. Martinos Center for Biomedical Imaging.
The scans showed that the brains of men with autism had lower levels of the protein than those of the healthy subjects.
The men with the most severe symptoms of autism tended to have the lowest amounts of TSPO, which affects inflammation and metabolism.
Autism is a developmental disorder that emerges in early childhood and is characterized by difficulty communicating and interacting with others.
The cause is unknown, but growing evidence has linked autism, which affects 1 in 59 children, to inflammation of brain tissue, or neuroinflammation.
The brain regions with low levels of TSPO are believed to control social and cognitive functioning such as processing of emotions, interpreting facial expressions, empathy and relating to others — key markers of autism.
Zurcher said the protein TSPO has a lot of roles aside from its impact on inflammation, including functioning of mitochondria, which produce energy in cells. Earlier research has linked malfunctioning mitochondria in brain cells to autism.
TSPO can be found in the brain using positron-emission tomography (PET) and anatomical magnetic resonance imaging. The MGH study was the first to use new generation of PET “tracers,” which more accurately detect TSPO.
Zurcher and her colleagues plan to study the brains of deceased donors to find out which brain cells in people with autism might experience dysfunction in mitochondria, which she said may be happening alongside neuroinflammation to cause autism.
“Our study has generated new hypotheses that now need to be investigated,” says Zurcher. “There’s more work to be done.”