REPLACING missing gut bacteria in a mouse model of autism reverses adverse social behaviours and gut disorders associated with the condition.
Last year, Sarkis Mazmanian and Paul Patterson at the California Institute of Technology in Pasadena found that infecting pregnant mice with molecules from a flu virus caused autism-like symptoms in their offspring. The pups were less social, squeaked less and displayed repetitive behaviours. They also had a "leaky" gastrointestinal tract that allowed bacteria to move in and out of the lining. In addition, the bacteria present in their gut were significantly different from that found in mice without autism-like behaviour.
Studies in humans have also identified links between gut bacteria and autism. For example, a 2011 study identified a significant lack of Bacteroides in children with autism.
To investigate further, Mazmanian and Patterson fed mice with autism-like symptoms a common species of Bacteroides. The mice's gut cells subsequently appeared to have stronger connections to one another, and stopped expressing genes for signalling molecules that raise the immune response. The animals' behaviour changed as well: they stopped the repetitive behaviour and squeaked more when with the opposite sex. The work waspresented at a recent TEDx conference in Pasadena.