Gut Microbes Linked to Autismlike Symptoms in Mice

[FarCenter]

Many physicians and parents report that their autistic children have unusually severe gastrointestinal problems, such as chronic constipation or diarrhea. These observations have led some researchers to speculate that an ailing gut contributes to the disorder in some cases, but scientific data has been lacking. Now, a provocative study claims that a probiotic treatment for gastrointestinal issues can reduce autismlike symptoms in mice and suggests that this treatment could work for humans, too.

The reported incidence of gut maladies in people with autism varies wildly between published studies—from zero to more than 80%—making it difficult to establish just how commonly the two conditions go together, says principal investigator Sarkis Mazmanian, a microbiologist at the California Institute of Technology (Caltech) in Pasadena. Overall, however, the evidence seems to point toward a connection. Last year, for example, a Centers for Disease Control and Prevention study of thousands of children with developmental disabilities found that kids with autism were twice as likely as children with other types of disorders to have frequent diarrhea or colitis, an inflammation of the large intestine.

...

The first step of the experiment was to determine whether the mice showed signs of gastrointestinal inflammation or other gut abnormalities, says microbiologist Elaine Hsiao, a postdoctoral candidate at Caltech and lead author of the study. By the time the mice were 3 weeks old, the researchers found that their intestines were indeed as leaky as those of mice that had been treated with a chemical that induces colitis. Next, the researchers tested whether they could reverse the damage by feeding the mice applesauce laced with B. fragilis for a week. A second group of autism-mimicking mice as well as a group of healthy mice ate applesauce that did not contain the bacteria. Then the group waited to see what effect the bacteria would have on the rodents' intestines. "We didn't know what would happen—we were hoping the bacterium would survive in the gut," Hsiao says.

After 3 weeks, the team measured the levels of gut-derived molecules in the rodents' bloodstream and found that the treatment had stopped up their intestinal leakage. Bacterial counts from rodents' poop showed that although B. fragilis did not establish lasting colonies in the mice, they did "shake up the community," of microorganisms, bringing it closer to that of the normal mice, Hsiao says. After the treatment, the autism-mimicking mice also resembled their normal peers in two behavioral tests, the authors report today in Cell. The animals no longer compulsively buried marbles in their cages and increased their ultrasonic squeaking to typical levels. They did not increase their social interactions, however, Hsiao says.

http://news.sciencemag.org/biology/2013/12/gut-microbes-linked-autismlike-symptoms-mice

[lumberjack_jeff]

1. It is frustrating that we know so little about this.

One in fifty boys (2%) will be born with ASD. How can we be so ignorant about it? We're still fighting about the definition, ffs.

They have known that there was a link between ASD and gastrointestinal disorders for twenty years.

[UtahLib]

2. Very interesting

I have a grandson who, while not yet fully diagnosed, is exhibiting signs of autism. I will be happy to pass this info on to my daughter.

[LiberalEsto]

3. Recently I read about a possible link between induced labor and autism spectrum

This makes me wonder whether some infants who are born via induced labor fail to pick up a sufficient amount of their mothers' gut bacteria on the way out, for whatever reason.

I could see how this could happen in a c-section, where the baby doesn't go through the birth canal.