In recent years, several studies have shown that the bacteria in our gut are linked to our overall health.
These gut bacteria can affect our mood, how we handle stress, and our chances of getting autoimmune diseases like rheumatoid arthritis and type 1 diabetes.
A new study in The Journal of Immunology gives new information about how gut bacteria might be connected to autism.
According to the World Health Organization, autism is a range of brain development conditions that affect how people interact and communicate with others.
The World Health Organization also says that people with autism often have other conditions like epilepsy, depression, anxiety, ADHD, and behaviors such as trouble sleeping or self-harming. Their thinking and learning abilities can be very different from person to person.
The study found that the bacteria in a mother’s gut may have a bigger effect on a child’s chances of developing autism than the child’s own gut bacteria.
John Lukens, a lead researcher and PhD student at the University of Virginia School of Medicine, explained that gut bacteria can affect how a baby’s brain grows. He said the microbiome helps shape how a child’s immune system reacts to things like infections, injuries, or stress.
One important piece of this puzzle may be a molecule made by the immune system called interleukin-17a, or IL-17a. This molecule is known to play a role in diseases like psoriasis, multiple sclerosis, and rheumatoid arthritis, and helps fight fungal infections. But it also seems to affect how the brain develops before birth.
To study this, scientists used mice with different types of gut bacteria. One group had bacteria that caused a strong immune response involving IL-17a, while the other group did not.
When scientists blocked IL-17a in the baby mice, both groups showed normal behavior. But once the treatment stopped and the mice grew naturally, those in the first group started to show signs linked to autism, like repeating certain actions.
Later, the researchers took poop from the first group and gave it to the second group through a fecal transplant, which passed the inflammation-causing gut bacteria to them. As expected, the second group of mice also began showing autism-like behavior.
Even though this study was only done on mice, it opens the door for more research into how a mother’s gut health might affect her child’s brain development.
John Lukens, the lead researcher, said that the next step is to find features in the gut bacteria of pregnant women that are linked to autism risk. He also mentioned that we need to learn how to safely change a mother’s gut bacteria during pregnancy.
While blocking IL-17a might help prevent autism, it’s risky. Pregnancy involves the body accepting the baby, which is like foreign tissue. This means the immune system has to stay carefully balanced, so doctors are usually cautious about changing it during pregnancy.
Lukens added that IL-17a is just one part of a much larger system, and there are many other molecules to study in the future.