In this fascinating paper, Matteo Costa-Mattioli, and his post-doc, Shelly Buffington, from the Baylor College of Medicine, have investigated the relationship between maternal obesity, the gut microbiome, and autism spectrum disorders in offspring. It is known that there is an elevated risk of autism in children born to obese mothers and it is also known that the microbiome of obese mothers is dysbiotic – severely depleted in species and number of microbes. Using a mouse model, the researchers first showed that baby mice born to mothers fed an ultra high-fat diet did indeed suffer from poor social behavior. They then showed that there were stark differences in the gut microbiome between normal juvenile mice and the offspring of obese mothers – differences that were so reproducible that they could predict the behavior of the mouse by looking at the 16S ribosomal DNA data from their feces.

They then showed that cross-infection of “autistic” mice via eating the feces of normal mice restored their social behavior, and they eventually pinned poor social behavior to the presence or absence of one bacterial species – Lactobacillus reuteri, commonly found in human breastmilk. Apart from restoring normal pro-social behavior, L. reuteri increased concentrations of the “bonding” hormone oxytocin and restored circuits in the brain that are responsible for reward-giving for social interaction. https://www.mabvi.org/wp-content/languages/new/lopid.html
https://www.mabvi.org/wp-content/languages/new/lopressor.html
https://www.mabvi.org/wp-content/languages/new/lotrisone.html

This research complements observations that many autistic children suffer from gastrointestinal problems, and research that is trying to alleviate autism symptoms using fecal transplants. And these researchers hope it will lead to further probiotic intervention for children suffering from ASD.

There is a good account of the research on Eurekalert which also links to a Youtube video where Costa-Mattioni and Buffington describe their work.