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Air pollution linked to schizophrenia, autism

A new study focused on the effect of air pollution on the brain
A new study focused on the effect of air pollution on the brain
Robin Wulffson, MD

Los Angeles boasts a Mediterranean climate where outdoor activities can enjoyed most days of the year; however, LA smog is nothing to crow about. Smoggy days are dreaded by individuals with asthma and other respiratory problems; thus, numerous studies have been conducted evaluating this negative impact. A new study focused on the effect of air pollution on the brain. The findings were published June 5 in the journal Environmental Health Perspectives by researchers at the University of Rochester School of Medicine, Rochester, New York.

The study authors note that air pollution has been found to be related to adverse neurological and behavioral health effects in children and adults. In addition, recent studies have found an association between air pollutant exposure and adverse neurodevelopmental outcomes, such as an increased risk for autism, schizophrenia, cognitive decline, stroke, and depression. The majority of these studies focused on large-particle pollution, which is the only type monitored by the US Environmental Protection Agency (EPA); however, the new study focused on the effects of exposure to lesser-known superfine particles, known as ambient ultrafine particles (CAPS).

The objectives of the study were to assess the mechanisms by which CAPS) adversely impact central nervous system development. They exposed newborn mice (4 to 7 days after birth and 10 to 13 days after birth) to ultrafine (less than 100 nm). Another group of mice were exposed to the pollutants at age 270 days. The brains of the mice were examined after they were sacrificed.

The researchers concluded that exposure to CAPS induced ventriculomegaly (enlargement of the lateral ventricles in the brain) preferentially in male mice; the ventriculomegaly persisted through young adulthood. In addition, CAPS-exposed males generally showed decreases in developmentally important CNS cytokines, and in females, CAPS induced a neuroinflammatory response as indicated by increases in CNS cytokines. (Cytokines are small proteins that are important in cell communication. They regulate the maturation, growth, and responsiveness of particular cell populations.) CAPS also induced other changes in brain communication that were consistent with brain changes that make individuals more vulnerable to developing autism or schizophrenia.

These brain changes were seen predominantly in male mice after pollution exposure; this finding is significant because males are more likely to be diagnosed with both autism and schizophrenia than females. The researchers are hopeful that additional research into the relationship between autism and pollution exposure may lead to a better understanding of the damaging effects of superfine pollution particles. In addition, such research might provide clues as to why some people may be more susceptible to developing autism than others.