Gastrointestinal (GI) disorders are frequently seen in persons with autism spectrum disorder (ASD).
Using a mice-model, a team of researchers at the California Institute of Technology (Caltech) conducted a study to investigate if changes in the GI tract through probiotic therapy in can influence autism-like behaviors.
Having a severe viral infection during pregnancy raises the risk of having a child with ASD. The researchers mimicked this immune-suppressed condition by inducing an infection-like response in pregnant mice mothers.
The researchers found that the mice offspring who exhibited autistic-like behaviors also exhibited GI abnormalities. The GI tracts of the autistic-like mice were “leaky” which means they allowed material to pass through the intestinal wall and into the bloodstream, a GI characteristic that has been observed in some individuals with ASD.
The GI-disordered and autistic-like mice were treated with an experimental probiotic therapy (bacteroides fragilis) that had been used in animal models of GI disorders. With the treatment, the “leaky” GI tracts of the mice were corrected, and some of the main behavioral autism symptoms improved.
As a result of these findings, the researchers plan to develop and test an effective and reliable probiotic therapy for ASD in humans.
The authors offer a word of caution – "Autism is such a heterogeneous disorder that the ratio between genetic and environmental contributions could be different in each individual. Even if B. fragilis ameliorates some of the symptoms associated with autism, I would be surprised if it’s a universal therapy — it probably won’t work for every single case." Nevertheless, the study authors suggest that “these results may someday transform the way people view possible causes and potential treatments for autism”.
From an article by Jessica Stoller-Conrad, Probiotic Therapy Alleviates Autism-like Behaviors in Mice. ScienceDaily, Dec 5, 2013. Reference: Hsiao E et al, Microbiota Modulate Behavioral and Physiological Abnormalities Associated with Neurodevelopmental Disorders. Cell, 2013.
Lirio S Covey – genetic and environmental factors are involved in the etiology of ASD. The study suggests that the immune-challenged condition of the mother during pregnancy is an autism-risk enhancing environmental factor, possibly an important one among many. The findings suggest a mode of post-natal treatment , i.e., probiotic treatment (as in live culture yogurt) that would be administered when autistic-like behaviors and GI symptoms are identified in the child. A further implication is careful monitoring and care of the mother during pregnancy to prevent, and (if it occurs) reduce the severity of immune-suppressive conditions such as a viral infection. The study indicates that the developmental path towards autism could begin during conception. How this process interacts with heritable genetic factors awaits further scientific inquiry.