There has been a lot of research recently about how the gut microbiome can affect our bodies in ways we wouldn’t even think of. Now, researchers are looking into how the make-up of the mother’s gut can affect the development of autism-spectrum disorders during pregnancy.
The gut microbiome of pregnant mothers is very important to how the offspring’s immune system is going to respond to an infection, injury, or stress. In the new study, researchers studied the inflammatory molecule interleukin-17a, or IL-17a, and found it was a key contributor to the development of autism-like symptoms in lab mice. John Lukens, the lead author on the study, likened the molecule as the ‘middleman between the gut and the brain’.
To test their theory researchers recruited female mice from two separate labs. Mice from one lab contained microflora in their gut which makes them prone to an IL-17a induced response, whereas the mice from the second lab did not. The team found that when IL-17a was artificially blocked, the pups from both sets of mice were born with neurotypical behaviour. However, when there was no human intervention, the pups born from the first group of mice containing microflora went on to develop an autism-like neurodevelopmental condition. This means that directly blocking IL-17a in pregnant mice prevented the development of neurodevelopmental disorders. However, translating this approach for human use will not be easy.
Directly blocking IL-7a in humans could do more harm than good. Since IL-17a comes from the immune system it may be risky to try and change the immune system during pregnancy and can put both the mother and foetus at risk of infections. While the effects of the gut microbiome could be prevented by directly blocking IL-17a, the researchers found that a healthy microbiome could also block IL-17a. It is encouraging that the study suggests autism-spectrum disorders could be prevented in offspring by modifying the mother’s diet, by taking custom probiotics, or through fecal transplantation as this would prevent an invasive treatment during pregnancy by directly blocking the molecule.
IL-17a has previously been implicated in other conditions, such as rheumatoid arthritis, multiple sclerosis and psoriasis and there are already drugs available that target IL-17a for these. However, as we mentioned, artificially blocking IL-17a during pregnancy can be a problem. Instead, researchers are now exploring the role of other immune molecules in the development of autism as IL-17a may only be one piece of the puzzle.
These are only preliminary studies and are a long way off from being trialled in human pregnancies, but it is an interesting avenue to explore in autism research and provides good evidence that the health of the mother’s gut plays some role in the development of neurodevelopmental conditions.