By Amanda Woerner, June 6, 2014
The skyline of downtown Los Angeles through a layer of smog is seen in
the distance from a rooftop in Hollywood, California, May 31, 2006.
Exposure to environmental pollution may cause brain changes that make
people more vulnerable to developing autism or schizophrenia, according
to a new study published in Environmental Heath Perspectives.
This research falls in line with a 2013 study published in JAMA Psychiatry,
which demonstrated an epidemiological link between pollution and
autism; the researchers found that children who lived in areas with high
levels of traffic pollution seemed to be more likely to be diagnosed
with the n
Now, researchers from the University of Rochester have uncovered the
biological mechanism that may explain how pollution can put people at a
higher risk for both autism and schizophrenia.
“From a toxicological point of view, most of the focus of air
pollution research has been on the cardiopulmonary system – the heart
and lungs,” study author Deborah Cory-Slechta, professor of
environmental medicine at the University of Rochester, told FoxNews.com.
“But I think it’s becoming increasingly clear that the adverse things
happening there are also happening in the brain, and this may be adding
to risks for neurodevelopmental disorders like autism that we hadn’t
thought about before.”
Cory-Slechta and her colleagues executed several experiments to
examine the effects of air pollution on different groups of young mice
during a critical time in the brain’s development. Each group of mice
was exposed to levels of air pollution equivalent to those seen in rush
After four hours of pollution exposure during two four-day periods,
mice exposed to pollution experienced marked changes in behavior
compared to mice living in an environment with filtered air.
“We see changes in learning produced by these exposures in males and
females, and in levels of activity, and we saw deficits in memory in
both males and females,” Cory-Slechta said. “We also had a measure of
attention, looking at impulsive-like behaviors, which we only tested in
males, and there too we saw the effects of postnatal exposure.”
These effects were lasting, with researchers reporting behavioral
differences between the two groups of mice even 10 months after the
initial pollution exposure.
The team also examined the brains of the mice exposed to pollution,
and discovered rampant inflammation and enlargement of the ventricles –
the chambers on either side of the brain containing cerebrospinal fluid.
In humans, enlarged ventricles are symptomatic of a brain condition
called ventriculomegaly, which is accompanied by varying degrees of
neurodevelopmental impairment. Furthermore, ventriculomegaly is often
associated with damage to the corpus callosum – the white matter tracts
sitting above the ventricles – which connect the two sides of the brain.
“[The corpus callosum] are important for processing cognitive kinds
of behaviors, social behaviors and emotional behaviors,” Cory-Slechta
said. “And autism is thought to be a disease in which that kind of
connectivity is lost, and you also see ventricular enlargement in autism
and schizophrenia as well.”
These brain changes were seen predominantly in male mice after
pollution exposure, which is significant because men are more likely to
be diagnosed with both autism and schizophrenia than women.
While most research on pollution focuses on large-particle pollution –
the only type monitored by the U.S. Environmental Protection Agency –
this research focused on the effects of exposure to lesser-known
“That kind of air pollution produces inflammation, it is going to
produce inflammation peripherally and in the brain as well. And when you
produce inflammation in the brain, you can kill cells there,”
Overall, Cory-Slechta hopes that more research into the connection
between autism and pollution exposure may lead to a better understanding
of the damaging effects of superfine pollution particles. Furthermore,
it could offer clues as to why some people may be more susceptible to
developing autism than others.
“I think in particular autism has been very difficult to discover the
ideology of, so to speak, we know there are genetic underpinnings but
they don’t fully account for [everything], and the leads in terms of,
‘Are there environmental exposures?’ have been relatively few,”
Cory-Schleta said. “And it might be interesting if it turns out air
pollution can contribute.”