Autism spectrum disorder (ASD) affects one out of fifty-nine eight-year-olds in the U.S.
A recent article in Medical News Today outlines a study conducted by neuroscientists from the Korea Brain Institute and Scripps Research in the US. The researchers, using animal models for the study, investigated the microglia (immune cells) in the developing brains of mice.
ASD Mostly Affects Males
It is well known that ASD mostly affects males. They are four times more likely to have the disorder than females. The most common symptoms of ASD are repetitive behavior, hypersensitivity to some sounds, and difficulty in social functioning.
New research suggests that during development, overproduction of protein in microglia (brain cells) may cause ASD. It is a function of normal microglia cells to reduce or “prune” the unnecessary synapses (nerve cell connections). Researchers found that due to a genetic mishap, the cells in mice were unable to perform this procedure. Male mice with this genetic fault exhibited autism-like symptoms accounting for three percent of ASD cases.
Identifying the Brain Cell
The study team identified the brain cells that are responsible for excess protein production. The team found that the ASD genes increase protein production due to high levels of the eIF4E molecule.
The team genetically engineered the mice creating high levels of eIF4E. The mice with overproduction of protein in microglial cells exhibited cognitive deficits and social behavior associated with ASD. This applies to male mice only.
Upon further investigation, the team discovered that the brains of male mice contained a high level of synapses.
In addition, the movement of the microglia was affected. This may account for the lack of the cells being unable to prune the excess synapses.
Scientists theorize that symptoms of autism may result if the brain’s excess synapses are not removed. Synapses are usually created and strengthened during normal development. If there are excess synapses in certain areas of the brain, it can create not only sensory overload but repetitive behavior as seen in ASD. It is believed that removal of excess synapses occurs each night in adults.
Although the neuroscientists were able to make certain determinations in their research using mouse models, it must be noted that there may be somewhat different effects of the condition in humans.
The new information garnered from this research suggests that microglia would be an excellent target for new drugs to treat or prevent ASD. The researchers were optimistic that these studies would bring about novel treatments in the future.