The reason that girls are less likely than boys to suffer from autism may have something to do with the same sex hormone receptor accountable for helping protect them from stroke, according to new information published Tuesday in the journal Molecular Autism.
With what has been called the first research into the role of estrogen in autism, experts from the Medical College of Georgia at Georgia Regents University examined the brains of people with autism spectrum disorders (ASD) and compared them to control subjects. They found that ASD was associated with far lower amounts of estrogen receptor beta.
Estrogen receptor beta, which enables estrogen’s capability to protect the brain, also plays a role in locomotion along with a number of behaviors, including anxiety, depression, memory and learning. Furthermore, the study authors also said that subjects identified as having autism also had significantly reduced amounts of other estrogen-related proteins.
“If you ask any psychiatrist seeing patients with autistic behavior their most striking observation from the clinic, they’ll say there are other males compared to females,” corresponding author and neuroscientist Dr. Anilkumar Pillai said in a statement, adding that his team’s research “is the very first indicator that estrogen receptors in the brain of Autism Spectrum Disorder patients may be dissimilar to controls.”
“Though this suggests a potential reason behind the gender bias, we still need determine what causes the reduced manufacture of estrogen-related proteins,” he added. “It is worth taking a look at whether drugs which modulate estrogen reception, but do not cause feminization, could allow for the long-term treatment of male patients with Autism Spectrum Disorders- However, additional studies are required to test the estrogen mechanism.”
According to the study authors, this might help explain why men’re five times much more likely than females to be autistic. Estrogen is known to assist in preventing stroke and cognitive decay in premenopausal women, while contact with high quantity of a male sex hormone testosterone during initial phases of development has been linked to ASD.
In addition to reduced expression of estrogen receptor beta within the brains of autism patients, the research authors found a smaller amount of an enzyme that helps convert testosterone to estrogen. Dr. Pillai believes that this discovery may help explain why autistic individuals tend to have higher testosterone levels, in addition to why men have higher autism rates.
“The testosterone hypothesis has already been there, but nobody had investigated whether it had anything to use the feminine hormone within the brain,” he explained. “Estrogen is known to be neuroprotective, but nobody has checked out whether its function is impaired in the brain of people with autism. We found that the kids with autism didn’t have adequate estrogen receptor beta expression to mediate the protective benefits of estrogen.”
Their comparison of kids with and without ASD revealed a 35 percent decrease in estrogen receptor beta expression along with a 38 percent decrease in the quantity of aromatase, the enzyme that converts testosterone to estrogen, the investigative team reported. Additionally, amounts of estrogen receptor beta proteins (active molecules caused by gene expression that enables functions such as brain protection) were also lower.
No discernible difference was discovered within the expression levels of estrogen receptor alpha, which mediates sexual behavior, the Medical College of Georgia researchers found. Their analysis focused on the prefrontal cortex C the region from the brain in social behavior and cognition C and used brain tissue from the Eunice Kennedy Shriver National Institute of kid Health insurance and Human Development Brain and Tissue Bank for Developmental Disorders.
Dr. Pillai said that estrogen receptor beta agonists, that have already been demonstrated to improve brain plasticity and memory in animals, could ultimately be used to help reverse some of the the signs of autism, such as reclusiveness and repetitive behavior.
He and his colleagues intend to begin animal studies to determine what affect reducing estrogen receptor beta expression has on mice by giving an estrogen receptor beta agonist to some rodent showing signs of autistic behavior. Future, larger-scale trials may also compare the expression of testosterone receptor levels in healthy and autistic children, the scientists said. They’re also curious why the reduced beta receptor expression occurs.
