Pandemic Discovery

Inflammation link for autism

A neuroimaging study has shown that the brains of young men with autism spectrum disorder have low levels of translocator protein, a substance that appears to play a role in inflammation and metabolism.

This discovery by a team of HMS researchers at Massachusetts General Hospital provides an important insight into the possible origins of autism spectrum disorder.

This developmental disorder, which affects one in fifty-nine children in the United States, emerges in early childhood and is characterized by difficulty communicating and interacting with others. Although the cause is unknown, growing evidence has linked it to neuroinflammation.

One sign of neuroinflammation is elevated levels of translocator protein, which can be measured in the brain using positron-emission tomography and anatomic magnetic resonance imaging.

The research team used these imaging tools to scan the brains of fifteen young adult males with the disorder. The group included both high- and low-functioning participants with varying degrees of intellectual ability. As a control, the team scanned the brains of eighteen non-autistic young men of similar age.

The scans showed that the brains of the young men with the disorder had lower levels of the protein, compared with the brains of non-autistic participants. In fact, those participants with the most severe symptoms of the disorder tended to have the lowest expression of the protein.

The brain regions found to have low expression of the protein have previously been linked to autism spectrum disorder and are thought to govern social and cognitive capacities such as processing emotions, interpreting facial expressions, and empathy.

The researchers point out that the translocator protein has multiple complex roles, some of which promote brain health. Adequate levels of the protein are, for example, necessary for normal functioning of mitochondria. Earlier research has linked malfunctioning mitochondria in brain cells to autism spectrum disorder.

Zürcher NR et al., Molecular Psychiatry, February 2020

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