According to a new study, chemicals found in typical glues, furniture textiles, and household disinfectants could damage supporting cells in the brain during critical developmental stages.
Two Chemical Classes Identified
Beginning with 1,823 compounds of mysterious toxicity present in the environment, molecular biologist Erin Cohn from Case Western Reserve University, together with colleagues, was able to identify two chemical classes that kill or halt oligodendrocyte cell maturation in a lab setting.
Oligodendrocytes are a type of support cell that wraps neurons to produce an insulating covering. This allows brain signals to travel at speed.
Among the two identified chemical classes, one was quaternary compounds used in hand sanitizers, disinfectant sprays, wipes, and other personal care products like mouthwash and toothpaste. These chemicals can be inhaled or ingested if incorrectly used or if one is in a space that is poorly ventilated.
The other compound class was organophosphates, which serve as flame retardants and can be found in glues, textiles, and other household items, such as electronics and furniture. These compounds can off-gas into the air of rooms that people usually spend time in. Since they are fat-soluble compounds, organophosphates can be absorbed into the skin and potentially reach the brain.
Findings were noted in the "Pervasive environmental chemicals impair oligodendrocyte development" study.
Chemicals Affecting Supporting Brain Cells
In mouse experiments, the pups that received a dose of one kind of quaternary compound were observed to have the chemicals detected in the brain tissue after days. This suggests that such compounds are capable of passing through the blood-brain barrier.
The animals were also observed to have depleted oligodendrocyte numbers in their brains after receiving ten daily doses of cetylpyridinium chloride, a certain kind of quaternary compound. This was administered five days after the animals' birth, which is a crucial period of brain development.
Researchers observed similar effects among brain organoids. Cohn explains that they observed that oligodendrocytes alone were notably vulnerable to such organophosphate flame retardants and quaternary ammonium compounds.
The team of Cohn also looked into the levels of a particular flame retardant by analyzing levels of BDCIPP, a flame retardant metabolite. They did so among urine samples of children gathered in the National Health and Nutrition Examination survey of the CDC between 2013 and 2018.
Nearly all of the 1,763 children, who were aged 3 to 11 years, had the retardant present in their urine. Children with the highest levels had a two and six-times higher likelihood of having adverse neurodevelopmental outcomes, such as motor dysfunction.
However, given the observational nature of the study, only associations and not direct causal relationships can be made. Nevertheless, the researchers argue that this is reason enough to delve deeper into the health impacts of such compounds, especially among children.
Health Concern
While the findings may sound alarming, experts are not very shocked by the lab results. Oliver Jones, an environmental chemist from RMIT University in Melbourne, explains that it does not matter whether something is toxic. Instead, it concerns whether something is toxic under conditions that people are likely exposed to.
In such a case, the cells in a Petri dish were exposed to relatively high compound amounts. This is not the same as what humans may typically encounter regarding exposure duration and dose route.
However, some individuals, such as hospital and school cleaners or individuals in correctional facilities, have higher exposure to quaternary compounds than others. This is because disinfectants of industrial strength are typically used in such settings.
While studies focusing on quaternary compound toxicity have been done primarily on cell and animal studies, more studies are now looking into human health impacts. It has been found that people have double the quaternary compound levels in their blood during the pandemic compared to before it started. This is likely due to the past use of disinfectants.
Because of this, some researchers consider these chemicals to be of emerging concern. Because of their vast diversity in structure, fully uncovering the risks posed by these compounds also presents challenges.
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