Autism: Birth hormone may control expression of the syndrome in animals

February 6, 2014

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Science Daily/INSERM (Institut national de la santé et de la recherche médicale)

A new article demonstrates that chloride levels are abnormally elevated from birth in the neurons of mice used in an animal model of autism. Researchers show for the first time that oxytocin, the birth hormone, brings about a decrease in chloride level during birth, which controls the expression of the autistic syndrome.

The scientific community agrees that autism has its origins in early life -- fetal and/or postnatal. The team led by Yehezkel Ben-Ari, Inserm Emeritus Research Director at the Mediterranean Institute of Neurobiology (INMED), has made a breakthrough in the understanding of the disorder.

In an article published in Science, the researchers demonstrate that chloride levels are elevated in the neurons of mice used in an animal model of autism, and remain at abnormal levels from birth.

These results corroborate the success obtained with the diuretic treatment tested on autistic children by the researchers and clinicians in 2012, and suggest that administration of diuretics to mice before birth corrects the deficits in the offspring.

They also show that oxytocin, the birth hormone, brings about a decrease in chloride level during birth, which controls the expression of the autistic syndrome.

"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," states Yehezkel Ben-Ari.

Taken together, these observations suggest that earliest possible treatment is essential for maximum possible prevention of the disorder.

This work raises the importance of carrying out early epidemiological studies in order to better understand the pathogenesis of the disorder, especially through analysing data on deliveries where a drop in chloride has occurred. Indeed, complicated deliveries with episodes of prolonged lack of oxygen, for example, or complications during pregnancy, such as viral infections, are often suggested as risk factors.

Finally, given the role of oxytocin in triggering labour, "although it is true that epidemiological data suggesting that scheduled caesarean deliveries may have increased the incidence of autism are controversial, it nonetheless remains that these studies should be followed up and extended in order to confirm or refute this relationship, which is still possible," insists Yehezkel Ben-Ari, who concludes, "To treat this type of disorder, it is necessary to understand how the brain develops and how genetic mutations and environmental insults modulate brain activity in utero."

http://www.sciencedaily.com/releases/2014/02/140206142121.htm