A recent study by the University of Iowa’s Psychiatry Department, presented in November at the 2018 Society for Neuroscience annual meeting in San Diego, showed that inflammation in the womb can cause autism-like traits in male mice.

Levels of the inflammatory marker interleukin-17  may be elevated in offspring with autism, the researchers appear to have discovered. The study relied on testing pregnant mice and injecting them with IL-17; researchers found that the females were not affected.

“A lot of the changes that we found overlap with changes in clinical populations of patients with autism, both at the level of gene changes and behavior displayed,” said UI psychiatry Associate Professor Hanna Stevens, a researcher on the study. “Also, the notion that males were affected parallels that boys are much more likely to be diagnosed with autism than girls.”

The exposed males were found to express 320 genes differently from those not exposed; 37 of those genes are linked to autism. Banu Gumusoglu, a graduate research assistant and a leader of the study, said it was evident to see how the mouse’s sex affected results.

“The clear and overwhelming nature of the sex-specific effects of this particular prenatal inflammatory manipulation was my biggest takeaway from this study,” Gumusoglu said. “It was striking to see such male-specific effects on behavior, offspring growth, and neurodevelopment.”

As adults, the exposed males weighed less, had smaller brains, and had less social interaction as adults, all of which are indications of autism-like traits that humans express.

“During pregnancy, the unborn fetus is undergoing a very rapid and profound development of the brain where connections are being established and continue after birth,” said Professor Lane Strathearn, a co-director of the Center for Disabilities and Development. “The capacity to develop social relationships and understand social cues may have its foundation in this developmental stage.”

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Strathearn said the placenta and womb transmit information to the fetus from the mother. For example, if a mother is stressed, this can affect the baby’s development.

“The in-utero environment has a direct effect on brain development,” Strathearn said.

Stevens plans on using data from the study to see how treatment with anti-inflammatories could possibly protect infants’ brains and reduce problems in mothers.

“We can measure and prevent molecules from harming the developing brain, as well see what might be going wrong in the brains of those with autism,” Stevens said. “I think that will benefit people by being combined with other research endeavors that show balance is needed for mothers and infants.”

Gumusoglu said the study has shown her how prominent autism-spectrum disorders are in the United States and that treatments vary in effectiveness.

“Iowa City, like the rest of the U.S., faces growing rates of autism-spectrum disorder,” Gumusoglu said. “With no medications available currently that target the core symptoms of autism, studies like this are important as they highlight potential mechanisms that might serve as treatment targets.”