The gut microbiomes of people with autism spectrum disorder (ASD) often differ to those of people without the condition. This may be partly due to ASD behaviour – for instance, people with ASD often have limited diets. But, there’s also evidence that the microbes themselves contribute to anxiety and other ASD-type behaviours. Indeed, recent research in mice has revealed that the metabolite 4EPS, produced by gut microbes, can induce anxiety and impair development of brain cells. Specifically, 4EPS hinders production of the protective sheath around neurons that ensures the cells fire correctly. The sheath, called myelin – stained green – is clearly present at higher levels in the brain tissue from a healthy mouse (left) than that of a mouse exposed to excess 4EPS (right). Given that 4EPS is also present at unusually high levels in the blood of ASD patients, it’s possible the metabolite has similar effects on the human brain.
Image from work by Brittany D. Needham and colleagues, Caltech
Division of Biology and Biological Engineering, California Institute of Technology (Caltech), Pasadena, CA, USA
Image copyright held by the original authors
Research published in Nature, February 2022
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