Autism is diagnosed when individuals exhibit characteristic behaviors that include repetitive actions, decreased social interactions and impaired communication.  Many parents and physicians have been stating for years that autism may really be an auto-immune or gastrointestinal (GI) condition that causes or exacerbates the symptoms of autism.

Researchers from CalTech explored the link between gut microbial and their impact on social and emotional behavior.  Their research which was published in the journal Cell is the first to demonstrate that changes in these gut bacteria can influence autism-like behaviors in a mouse model.

"Traditional research has studied autism as a genetic disorder and a disorder of the brain, but our work shows that gut bacteria may contribute to ASD-like symptoms in ways that were previously unappreciated," says Professor of Biology Sarkis K. Mazmanian. "Gut physiology appears to have effects on what are currently presumed to be brain functions."

To study this gut-microbiota-brain interaction, the researchers used a mouse model of autism previously developed at Caltech. In humans, having a severe viral infection raises the risk that a pregnant woman will give birth to a child with autism. Patterson and his lab reproduced the effect in mice using a viral mimic that triggers an infection-like immune response in the mother and produces the core behavioral symptoms associated with autism in the offspring.

In the new Cell study, researchers found that the "autistic" offspring of immune-activated pregnant mice also exhibited GI abnormalities. In particular, the GI tracts of autistic-like mice were "leaky," which means that they allow the material to pass through the intestinal wall and into the bloodstream. This characteristic, known as intestinal permeability, has been reported in people with autism. "To our knowledge, this is the first report of an animal model for autism with comorbid GI dysfunction," says Elaine Hsiao, a senior research fellow at Caltech and the first author on the study.

To see whether these GI symptoms actually influenced the autism-like behaviors, the researchers treated the mice with Bacteroides fragilis, a bacterium that has been used as an experimental probiotic therapy in animal models of GI disorders.

The result? The leaky gut was corrected.

In addition, observations of the treated mice showed that their behavior had changed. In particular, they were more likely to communicate with other mice, had reduced anxiety, and were less likely to engage in a repetitive digging behavior.

"The B. fragilis treatment alleviates GI problems in the mouse model and also improves some of the main behavioral symptoms," states researcher, Hsiao. "This suggests that GI problems could contribute to particular symptoms in neurodevelopmental disorders."

With the help of clinical collaborators, the researchers are now planning a trial to test the probiotic treatment on the behavioral symptoms of human autism.

"This probiotic treatment is postnatal, which means that the mother has already experienced the immune challenge, and, as a result, the growing fetuses have already started down a different developmental path," states researcher, Patterson . "In this study, we can provide a treatment after the offspring have been born that can help improve certain behaviors. I think that's a powerful part of the story."

The Caltech team proposes that particular beneficial bugs are intimately involved in regulating the release of metabolic products (or metabolites) from the gut into the bloodstream. Indeed, the researchers found that in the leaky intestinal wall of the autistic-like mice, certain metabolites that were modulated by microbes could both easily enter the circulation and affect particular behaviors.

"I think our results may someday transform the way people view possible causes and potential treatments for autism," researcher, Mazmanian says.

At Healing 4 Soul, we have seen wonderful results using probiotics with people of all ages with autism.  In fact, probiotics are part of our overall CEASE Therapy program.  If we can be of help to you or your child, please phone us at 310-738-8878 to schedule your comprehensive consultation.