Research: Gut microbiota health linked to autism

by Jacob Fuller

Lauren Dempsey, MS in Biomedicine and Law, RN, FISM News 


New research published in Neuroscience may show a connection between autism spectrum disorder (ASD) and microbiota in the digestive tract, giving further insight into the condition that affects more than 2% of children born n in the United States according to the CDC.

Researchers from the University of Rome Tor Vergata and the University of Calabria conducted studies on mice that evaluated the impact of transplanting fecal microbiota from children with autism spectrum disorder (ASD). This “led to the colonization of ASD-like microbiota and autistic behaviors.”

Researchers compared this group of mice to a second group that was exposed to valproic acid, which is commonly used to treat seizure disorders, bipolar disorder, and migraines, as well as a control group. They found that there were elevated levels of pro-inflammatory markers in the brain and small intestine of the mice transplanted with fecal microbiota from donors with autism.

They also recorded increased “villous atrophy and inflammatory infiltration” in the small intestine of both the fecal microbiota transplant mice and those given valproic acid. They found that these changes “were linked to a decrease in the methylation status.”

More simply put, the mice that had the fecal transplants from donors with autism had changes in the fingerlike projections that are important in nutrient absorption, and factors that increased gut inflammation were present.

There was also a decrease in methylation status, which is a chemical process essential to every cell in the body. Such a decrease has been linked to chronic disease, as well as dysregulation of important enzymes, hormones, and the body’s ability to get rid of toxins.

The mice that received the fecal microbiota transplant exhibited unusual behaviors during maze tests, which lead author Ennio Avolio and his team to suggest their findings may point to a correlation between gut health and ASD.

Autism spectrum disorder is a disability with a wide range of conditions and symptoms causing social, communication, and behavioral challenges. According to the CDC, 1 in 44 children is diagnosed with autism, a disorder that crosses all racial and socioeconomic groups. ASD is four times more common among boys than girls. The likelihood of diagnosis has increased significantly over the past several years, with a recent study showing a 52% increase in autism spectrum disorder (ASD) in children and adolescents during a three-year period.

There is no known cause of autism, although there has been speculation of a link between environmental exposures and genetic factors.

While the authors conclude that more research needs to be done, the “overall, findings of the present study corroborate a key role of gut microbiota in ASD,” they wrote. “Further investigations are required before any possible manipulation of gut bacteria with appropriate diets or probiotics can be conducted in ASD individuals.”

The study was based on previous research that highlights the important role that gut bacteria plays in overall health.

“In recent years, numerous studies have revealed differences in the bacterial composition of the gut microbiome between individuals with ASD and neurotypical [people],” wrote Sarkis Mazmanian, author of a similar study published in Cell. “While this previous research identifies potentially important associations, it is unable to resolve whether observed microbiome changes are a consequence of having ASD or if they contribute to symptoms.”

Researchers are hopeful that further studies will identify the cause and may lead to improved treatment and management of ASD.

The gut is often called the “second brain” and plays an important role in physical and psychological health. The gastrointestinal tract houses the enteric nervous system (ENS), which is made up of two thin layers that contain more than 100 million nerve cells.

The ENS communicates directly with the central nervous system (CNS) and directly affects the endocrine system, immune system, and microbiota. Researchers have found that this gut-brain connection goes both ways, as they directly impact each other. Understanding how this contributes to overall health may help scientists improve treatment for disease and psychological disorders in the future.