Drug Shows Promise in Reversing Symptoms of Autism, Researchers Say
Autism might be a result of poor-functioning chemical switch during pregnancy that doesn't flip in time, according to a new study.
Researchers said that a diuretic pill such as bumetanide, which is used to treat fluid retention in people with high blood pressure, could be used to reverse autism. The team has financial stake in the drug that they used in the study, according to U.S Today.
Autism Spectrum Disorders (ASD) is a group of developmental disabilities that can lead to social, communication and behavioral challenges. Research has shown that both genes and environment raise autism risk. Currently, there is no cure for the condition.
Chloride Channels, GABA and Oxytocin
The team led by Yehezkel Ben-Ari, Inserm Emeritus Research found that chloride levels are abnormally high in animal models with autism. Previous research by the team, published in 2012, had shown that diuretics or "water pills" given during pregnancy and just before delivery lowered the chloride levels and reduced symptoms of autism.
During normal embryonic growth, GABA- the main chemical messenger in the brain- excites neurons. This higher excitation helps the brain develop faster. At the end of the pregnancy, the hormone oxytocin, with the help of GABA again, flips a chemical switch that lowers the levels of chloride and reduces neuron excitement by as well.
However, in some cases, this chemical switch fails to flip at the right time, leading to autism-like behavior. According to the researchers, this chemical pathway may explain why some children develop autism.
"Chloride levels during delivery are determinants of the occurrence of autism spectrum disorder," explained Yehezkel Ben-Ari, an Emeritus Research Director at Inserm, according to a news release.
The present study was based on animal models; a genetic model with Fragile X syndrome, a mutation associated with autism and an animal whose mother was injected with sodium valproate during pregnancy. Sodium valproate has been linked with autism-like behavior.
Researchers found that the test animals had higher levels of chloride during delivery whereas the control group had reduced chloride levels and normal brain activity.
The team then administered a diuretic to the test mice 24 hours before delivery. They found that the treatment restored the brain activity to normal levels.
Researchers also blocked the activity of oxytocin during birth in some of the test rodents. Lower activity of the hormone resulted in autism-like symptoms in the animals.
"These data validate our treatment strategy, and suggest that oxytocin, by acting on the chloride levels during delivery modulates/controls the expression of autism spectrum disorder," said Yehezkel Ben-Ari.
Loopholes of the Study
While some researchers have welcomed the test results, some have raised questions. They claim that what works on rodents such as mice and rats may not always work on humans.
"I think 90 percent of this paper is really earth-shattering, but there's always the caution of, 'is this going to work in humans, a more advanced mammal?'" said G. Ian Gallicano, a molecular and cell biologist at Georgetown University in Washington DC told Livescience. Gallicano wasn't part of the new research.
Also, Fragile X account for about five percent of cases while sodium valproate for nearly 4 percent cases, meaning that there are other factors that increase autism risk.
According to an article in Forbes, oxytocin use in delivery rooms during c-sections has been associated with increased odds of autism. Also, there are no approved tests for in-utero detection of autism.
The study is published in the journal Science.