Researchers at the University of Colorado Boulder have discovered that a combination of pre-natal stress and an unapproved pre-term labor medication called terbutaline may create a higher risk for the co-development of autism and epilepsy based on test results involving laboratory rats.
The new study, which was published today in The Journal of Neuroscience, indicates that the use of terbutaline, a drug sometimes used to delay labor by up to 72 hours, may increase the risk of a fetus developing both autism and epilepsy, but only when combined with elevated stress levels on the part of the pregnant mother.
The findings may open up new avenues of clinical investigation for autism and epilepsy research, with potential applications for humans further down the line.
“With this new animal-based research model in place, we can start looking at neurological mechanisms that we haven’t been able to in the past and explore why there is a connection between epilepsy and autism and how to decrease risk for both disorders,” said Daniel Barth, a professor in the Department of Psychology and Neuroscience at CU-Boulder and a co-author of the study.
Autism and epilepsy commonly manifest together, with about 30 percent of autistic patients exhibiting epileptic symptoms such as seizures. Previous research has suggested that genetics can play a role in the development of both syndromes, but the impact of pre-natal environmental, non-genetic factors has received less attention.
Terbutaline is a drug that prevents the constriction of airways and is approved for treating asthma, bronchitis and emphysema. The U.S. Food and Drug Administration has cautioned against the use of terbutaline to delay pre-term labor.
Premature births affect roughly one in six pregnancies and premature labor often results from maternal stress. Since terbutaline can be used to arrest preterm labor, maternal stress followed by terbutaline administration becomes more likely.
The CU-Boulder researchers found that although pre-natal stress or terbutaline alone can increase the risk of autism in newborn rats, the more severe neurological syndrome of combined autism and epilepsy manifested only when both factors were in play simultaneously.
“We’ve learned that this combination of risk factors is far greater than either one alone,” said Barth. “This is the first research in this area to show how environmental factors can operate in tandem rather than individually.”
Edward Dudek, a professor in the Department of Neurosurgery at the University of Utah, co-authored the study along with graduate students and post-doctoral researchers from CU-Boulder including Alex Benison, lead author Florencia Bercum, Heidi Grabenstatter, Elise Kornreich, Krista Rodgers, Zachariah Smith and Jeremy Taylor.
The research was supported by grants from Autism Speaks and the U.S. Army Medical Research and Material Command.