Study Suggests We’re Surrounded by Threats to Brain Health

Case Western Reserve University School of Medicine researchers have uncovered new insight into the threats that some everyday household chemicals pose to brain health.

The research proposes that chemicals in a wide swath of household items might influence the development of neurological diseases, such as multiple sclerosis and autism spectrum disorders.

Looking Beyond Genetics

Despite the growing prevalence of neurological disorders – more than 3 billion worldwide now, according to the World Health Organization – scientists are rarely able to link the diagnosis to genetics alone. As a result, researchers have long suspected – but so far unidentified – environmental factors might play a role.

The research results, published in the latest issue of the journal Nature Neuroscience, found that some common home chemicals act on the brain’s oligodendrocytes. This specialized cell type generates the protective insulation around nerve cells.

“Loss of oligodendrocytes underlies multiple sclerosis and other neurological diseases,” the study’s lead researcher, Paul Tesar, director of the Institute for Glial Sciences at the School of Medicine, wrote. “We now show that specific chemicals in consumer products can directly harm oligodendrocytes, representing a previously unrecognized risk factor for neurological disease.” 

Methodology

The researchers investigated more than 1,800 chemicals that humans come into contact with regularly. As a result, the team was able to identify two types of chemicals that “selectively damaged” oligodendrocytes:

• Organophosphate flame retardants, present in most personal electronics and furniture.
• Quaternary ammonium compounds, used in multiple personal-care products and disinfectants.

The researchers worked with both cellular and organoid systems to illustrate that quaternary “ammonium compounds cause oligodendrocytes to die, while organophosphate flame retardants prevented the maturation of oligodendrocytes.”

Subsequently, the researchers showed how those same chemicals damage oligodendrocytes in the developing brains of mice. The researchers also tied the exposure to one of the chemicals to poor neurological outcomes in children.

“We found that oligodendrocytes — but not other brain cells — are surprisingly vulnerable to quaternary ammonium compounds and organophosphate flame retardants,” Erin Cohn, another author and graduate student in the School of Medicine’s Medical Scientist Training Program, said. “Understanding human exposure to these chemicals may help explain a missing link in how some neurological diseases arise.”

More Brain Health Research Needed

The authors added that the community must further investigate this emerging link between these chemical exposures and brain health. Such research should include “tracking the chemical levels in the brains of adults and children to determine the amount and length of exposure needed to cause or worsen disease.”

“Our findings suggest that more comprehensive scrutiny of the impacts of these common household chemicals on brain health is necessary,” Tesar added. “We hope our work will contribute to informed decisions regarding regulatory measures or behavioral interventions to minimize chemical exposure and protect human health.”