A recent study, based on autopsies, detected microplastics in the olfactory bulbs, the smell centers of the human brain. The study revealed that these tiny floating microplastics in the air entered the brain likely through breathing.

The latest study published in Jama Network Open that analyzed the olfactory bulbs of 15 deceased individuals using micro-Fourier transform infrared spectroscopy found the presence of microplastics in the olfactory bulbs of 8 individuals.

"The presence of microplastics in the human olfactory bulb suggests the olfactory pathway as a potential entry route for microplastics into the brain, highlighting the need for further research on their neurotoxic effects and implications for human health," the researchers noted.

Microplastics are a known threat to ecosystems and human health. They typically enter the human body through oral intake, inhalation, and skin contact. Research indicates that microplastics can cause oxidative stress, DNA damage, organ dysfunction, metabolic disorders, immune responses, neurotoxicity, and reproductive and developmental toxicity.

Earlier studies have detected microplastics in various human tissues, including the lungs, intestines, liver, blood, testicles, and semen. It was previously believed that the body's protective blood-brain barrier would keep these particles out of the brain. Therefore, the latest study is the first to detect microplastics in the human brain.

The researchers identified 16 synthetic polymer particles and fibers in 8 of the 15 deceased individuals, ranging from 1 to 4 microplastics per olfactory bulb.

"Our data support the idea that the olfactory pathway is an important entry site for environmental air pollutants. Considering the potential neurotoxic effects caused by microplastics in the brain, and the widespread environmental contamination with plastics, our results should raise concern in the context of the increasing prevalence of neurodegenerative diseases," the researchers concluded.

"With much smaller nano-plastics entering the body with greater ease, the total level of plastic particles may be much higher. What is worrying is the capacity of such particles to be internalized by cells and alter how our bodies function," said study researcher, Thais Mauad, an associate professor of pathology at the University of Sao Paolo in Brazil in a news release.

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