Scientists say they have used an experimental compound to reverse two autism-like behaviors in mice. Experts say there's no guarantee the drug would work to help children with autism, a neural developmental brain disorder marked by communication and social impairments beginning in early childhood. But they say it's a step in the right direction.
Researchers with the U.S. National Institute of Mental Health and the Pfizer pharmaceutical company tested the drug called GRN-529 in mice that normally display autistic-like activities - in particular, social isolation and repetitive behaviors. NIMH co-investigator Jill Silverman says that after being injected with the experimental compound, the mice reduced two of their repetitive behaviors - obsessive grooming and jumping - and the normally asocial rodents engaged more with other mice.
Researchers say the experimental compound dampens the activity of the brain chemical glutamate by modifying one of its chemical receptors. That could target a number of autistic behaviors linked to a defect in connections between brain cells or neurons.
But they don't know for sure. Silverman says the biochemical mechanism of GRN-529 is not completely understood, though she's not surprised that adjusting the biological activity of glutamate, which helps stimulate neurons throughout the brain, might reverse some of autism's core symptoms.
"It's crucially involved in every connection in the brain, basically," said Silverman. "So, modulating its effects by acting at one receptor seems to be a very promising target."
Robert Ring was involved in the GRN-529 study at Pfizer and is now vice president of translational research with Autism Speaks, an non-profit scientific funding and advocacy group.
Ring says the possibility of a drug that could treat the symptoms of autism, even if it's not a cure, could improve the quality of life for autistic individuals by making behavioral interventions more effective.
"Individuals living with autism don't just encounter struggles with the core symptoms that have been defined for autism," said Ring. "But they have a whole host of associated psychiatric and neurological syptoms that also reduce the quality of life for them. And any agent that has the potential to reduce these may bring significant benefit to this population."
The experimental compound is currently in clinical trials for individuals with a disorder called fragile x syndrome, which is caused by a single mutated gene. Fragile x is the most commonly inherited form of intellectual impairment, often with autistic symptoms.
Because the mice are born with the autistism-like tendencies, researchers know that GRN-529 might not work in children with autism. But then again, it might.
An article on GRN-529 in mice is published in Science Translational Medicine.