25/07/2020
- Before Ethan Loyola reached his first birthday, it was clear that something was wrong with his gut. Around the age of one, Ethan lost the words he’d started to say and stopped making eye contact. Soon after that, he received a diagnosis: autism spectrum disorder (ASD).
- Scientists at Arizona State University were looking for children with autism to try an experimental treatment called microbiota transfer therapy, which would be used to recolonize the children’s guts with bacteria from donors who were not on the autistic spectrum. Ethan’s parents enrolled him in the study.
- Researchers are revealing that in addition to aiding digestion, gut bacteria also manufacture bioactive compounds that help to orchestrate brain function and social development.
- Studies show that children with ASD often have a mix of gut microbes that is distinct from that in children without the condition. And in lab animals, autism-like symptoms arise when normal species of gut bacteria are absent.
- Studies have showed that when gut bacteria help to digest food, they generate a host of by-products that can affect thinking and behaviour. Clostridia bacterial pathogens, for instance, generate propionic acid in the gut — a short-chain fatty acid known to disrupt the production of neurotransmitters. Propionic acid also causes autism-like symptoms in rats, such as repetitive interests, unusual motor movements and atypical social interactions.
- For Ethan, after the microbiome transfer, his diarrhoea and cramping disappeared in months. But most dramatic was his new interest in people. He began waking up with a smile, crowing, “Good morning!” He also started asking questions, such as ‘why is the sky blue and the clouds white?’ something he had not done before, his family says. In social-skills tests, Ethan, who is now 12, scores in the same range as children who are not on the autistic spectrum.
- Did Ethan make these strides because his crippling stomach pain went away? Or have the new microbes truly changed the way his brain works? No one knows for sure. But Ethan’s family welcomes the research. “The study was the tipping point,” his mother says. “It was completely life altering.”