Experimental drug reduces autism symptoms in mice, gov't study shows
(CBS News) Autism affects one out of every 88 American children and while there are available treatments for early intervention, there is no cure. A new government-funded study has found an experimental treatment is effective at reversing symptoms of autism in mice.
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For the study, published in the April 25 issue of Science and Translational Medicine, researchers from the National Institutes of Health bred a strain of mice to display autism-like behaviors. Similar to how children with autism have social deficits and engage in repetitive behaviors, these mice did not interact and communicate with each other and spent an inordinate amount of time engaging in repetitive behavior - in this case self-grooming.
Cue the experimental drug called GRN-529. The drug was designed to inhibit a type of brain cell receptor that receives the neurotransmitter glutamate. Glutamate is typically involved in learning and memory processes and stimulates other areas of the brain and nervous system.
When mice with the autism-like behaviors were injected with the experimental compound, they reduced the frequency of their repetitive self-grooming and spent more time around strange mice, even sniffing them nose to nose. When tested on a different strain of mice, the experimental compound stopped all repetitive jumping behavior.
"These new results in mice support NIMH-funded research in humans to create treatments for the core symptoms of autism," Dr. Thomas R. Insel, director of the National Institute of Mental Health, said in a statement. "While autism has been often considered only as a disability in need of rehabilitation, we can now address autism as a disorder responding to biomedical treatments."
The researchers said although most mouse brain findings often don't translate to humans, the fact that these compounds are already being tested for an overlapping condition strengthens the case for the drug's effectiveness. This class of compounds is currently being studied in patients with the genetic disease Fragile X syndrome, the most common inherited form of intellectual disability. About one third of patients with Fragile X syndrome also meet criteria for autism.
"These inbred strains of mice are similar, behaviorally, to individuals with autism for whom the responsible genetic factors are unknown, which accounts for about three fourths of people with the disorders," noted study author Dr. Jacqueline Crawley of the NIMH. "Given the high costs - monetary and emotional - to families, schools, and health care systems, we are hopeful that this line of studies may help meet the need for medications that treat core symptoms."
Some experts exercised caution with the new findings. In an accompanying editorial in the same journal issue, Baltazar Gomez-Mancilla, executive director of translational medicine neuroscience at Novartis, wrote, "It is too early to speculate as to whether or not autism spectrum disorders can be reversed by small molecules."
Dr. Uta Frith, a professor of cognitive development at University College London, told BBC News that neurotransmitter problems have long been suspected as an origin of autism, "However, it will be a long time until these findings can be translated for human patients. Tampering with the synapse may well result in undesirable side effects," he said.
Here is a video of the improved sociability in mice on the experimental treatment:
