Preventing autism may start with mother’s diet
The risk of developing autism-spectrum disorders may be determined by the mother’s microbiome, according to new research from the University of Virginia School of Medicine published August 1 in the Journal of Immunology.
This study raises the possibility that preventing forms of autism could be as simple as an expectant mother modifying her diet or taking custom probiotics, researchers say.
In addition, researchers were able to use their discovery to prevent the development of autism-like neurodevelopmental disorders in lab mice. They found they could halt the development of such disorders by blocking a particular inflammatory molecule produced by the immune system. Targeting this molecule, interleukin-17a, offers another potential avenue for preventing autism, the researchers say. They caution, however, that this approach would be much more complex because of the risk of side effects.
"We determined that the microbiome is a key contributor in determining susceptibility [to autism-like disorders], so it suggests that you could target either the maternal microbiome or this inflammatory molecule, IL-17a," said John Lukens, PhD, lead researcher and member of UVA's Department of Neuroscience. "You could also use this [IL-17a] as a biomarker for early diagnosis."
The work from Lukens and his colleagues sheds light on the complex relationship between the health of the mother's microbiome and the healthy development of her children.
"The microbiome can shape the developing brain in multiple ways," said Lukens. "The microbiome is really important to the calibration of how the offspring's immune system is going to respond to an infection or injury or stress."
But an unhealthy microbiome in the mom can create problems. Lukens says. His work shows that it can make her unborn offspring susceptible to neurodevelopmental disorders. The researchers found that the IL-17a molecule was a key contributor to the development of autism-like symptoms in lab mice.
However, Lukens says the microbiome can be modified easily, either through diet, probiotic supplements, or fecal transplant. All of these approaches seek to restore a healthy equilibrium among the different microorganisms that live in the gut.
"In terms of translating our work to humans, I think the next big step would be to identify features of the microbiome in pregnant mothers that correlate with autism risk," Lukens said. "I think the really important thing is to figure out what kind of things can be used to modulate the microbiome in the mother as effectively and safely as we can."
Blocking IL-17a might offer a way to prevent autism, but Lukens said that path carries much more risk.
"If you think about pregnancy, the body is basically accepting foreign tissue, which is a baby," he said. "As a result, maintenance of embryonic health demands a complex balance of immune regulation, so people tend to shy away from manipulating the immune system during pregnancy."
IL-17a previously has been implicated in conditions such as rheumatoid arthritis, multiple sclerosis, and psoriasis, and there are already drugs available that target it. Lukens said that the molecule has an important purpose in stopping infections, especially fungal infections. Blocking it, he said, "could make you susceptible to all kinds of infections." And doing so during pregnancy could have complex ripple effects on a child's development that scientists would need to sort out.
For their next steps, Lukens and his team plan to explore the potential role of other immune molecules in the development of autism and other such conditions. IL-17a may be just one piece in a much larger puzzle, he said.
While Lukens' work links the immune system with neurodevelopmental disorders, he emphasized that this in no way suggests that vaccines are contributing to the development of autism.
"There's a definite link between the immune response and the developing brain," he said. "It just doesn't have anything to do with vaccines. It's much, much earlier."