Researchers have identified a novel compound that improved autism-like behaviors in mice, according to a new study published in the journal Science Translational Medicine.
Scientists from the National Institutes of Mental Health (NIMH) and Pfizer Worldwide Research and Development found that an experimental agent known as GRN-529 that inhibited the actions of a glutamate, a chemical in the brain, caused mice to be more social and engage in less repetitive grooming. Social deficits and repetitive behaviors are two of the core symptoms of autism spectrum disorders.
While findings in mice may not always be applicable to humans and research into this compound is in a very early stage, lead researcher Jill Silverman of the NIMH said so far, the data are encouraging.
"This is the first step in a very long process," she said. "But the results are important because there are no drugs that are currently available to autistic patients that address any of the core symptoms. The only drugs that are prescribed are for irritability that can lead to tantrums and for self-injurious behavior."
The two approved drugs - Risperdal and Abilify - are anti-psychotics and can have dangerous side effects, she added.
The mice used in the study are commercially bred to exhibit symptoms that strongly resemble those often seen in autism. They displayed very low levels of social interaction and also repeatedly groomed themselves so excessively that in some cases, their hair started to fall out, Silverman explained.
The mice also did not vocalize much, reflecting the communication deficits seen in people with autism.
The animals who received GRN-529 groomed themselves less and spent more time interacting with other mice. Another group of mice exhibited less repetitive jumping.
In an accompanying editorial, Baltazar Gomez-Mancilla, a researcher with the pharmaceutical company Novartis, wrote that these findings along with previous study data suggest that the effects of these agents should soon be tested on humans with autism.
But it will take more research to determine whether any future drugs should be used at the time of diagnosis, and which patients could potentially benefit the most from this type of agent, since autism is so highly variable.