Study: Health of a pregnant mom’s gut can indicate risk of autism

July 18, 2018 GMT

CHARLOTTESVILLE, Va. — Preventing autism could be as simple as modifying an expectant mom’s diet, according to new research from the University of Virginia.

For more than a decade, scientists have suspected that autism spectrum disorders might be linked to inflammatory molecules. Although autism, characterized by difficulty socializing and often accompanied by repetitive behaviors, primarily impacts the brain, links to gastrointestinal systems have become clear in recent research. But UVa research pushes that link much earlier in the development of a child, finding that the gut of pregnant women who have experienced inflammation can be a marker for the neurodevelopmental health of their child.

“This cytokine, [interleukin-17], has been implicated in autism before, and it’s known that certain bacteria that live in the microbiome can push the immune system towards creating more of this cytokine,” said Catherine Lammert, a doctoral student in the Brain Immunology Glia center who was first author on recent paper studying the impact. “It elevates the level of inflammation.”

Lammert worked with John Lukens, an assistant professor in UVa’s Department of Neuroscience, to weave together a study that would account for multiple markers linked to autism.

Women who experience a flare of multiple sclerosis, arthritis or a viral infection during pregnancy are much more likely to have an autistic child, Lukens said.

“There’s a lot of speculation about the role of the microbiome in autism,” Lukens said. “A lot of that has come from studies of autistic individuals that have different microbiomes and gastrointestinal inflammation. Various people have also had decent responses to diet changes. But understanding of how that actually works has been lacking, and what Cat showed was that the microbiome has a huge impact of susceptibility to autism during pregnancy, which is new.”

Lammert injected pregnant mice with a drug to mimic a viral infection and trigger inflammation. Once mice pups were born, Lammert tested the pups against a control group to see if they communicated and socialized normally. The mice born from the injected mothers were more likely to vocalize less, be antisocial and engage in repetitive behavior.

The research strengthens the growing body of evidence that indicates how much influence the immune system has on the central nervous system, Lammert said.

“It also stresses the importance of prenatal health, whether that’s prenatal vitamins or microbiome health,” Lukens added. “One of the implications could be if you were predisposed to inflammation and if you knew what that signature was, you could screen for it. But that’s pretty far off — we’re not there yet.”

Currently, a child is typically not diagnosed with autism by a professional until he or she is 2 years old. Recent statistics suggest that one in 59 children has an autism spectrum disorder, according to the Centers for Disease Control and Prevention.

The “holy grail” of autism research will be to diagnose the disorder earlier and, eventually, prevent it, Lukens said.

“The earlier you can study the process, the better,” Lukens said.

Lukens added that the team’s and other research has found no link between receiving a vaccine and developing autism. A 2013 CDC study showed that the number of antigens from vaccines during the first two years of a child’s life was the same between children with and without autism spectrum disorders.

The UVa researchers didn’t suggest specific clinical changes or diet changes for expectant moms — future research might involve testing high-fat and low-fat diets in mice to see how inflammatory responses and microbiomes vary, they said.

It’s also possible that different cytokines could interact and cause different outcomes. In future research, they would like to explore the potential role of other immune molecules.

The article is published in the Journal of Immunology. The research team at UVa also included Elizabeth Frost, Ashley Bolte, Matt Paysour, Mariah Shaw, Calli Bellinger, Thaddeus Weigel and Eli Zunder.