Research shows that breathing can introduce microplastics into the human brain

For the first time, scientists have discovered microscopic microplastics found in the human brain. Researchers in Germany and Brazil say that 8 out of 15 autopsy adults had microplastics detected in the olfactory centers of their brains, the olfactory bulb.

The particles have likely been inhaled over a lifetime, as tiny floating microplastics are ubiquitous in the air.

Although microplastics have been found in human lungs, intestines, liver, blood, testicles and even semen, it was long thought that the body’s protective blood-brain barrier could keep the particles out of the brain.

However, the new study suggests that there is “a potential route for the translocation of microplastics to the brain” via the olfactory bulb, according to a team led by Luis Fernando Amato-Lourenco of the Free University of Berlin and Thais Mauad, associate professor. pathology at the University of Sao Paulo in Brazil.

The team published his findings September 16 in the journal JAMA network opened.

“With many smaller nanoplastics entering the body more easily, the overall level of plastic particles may be much higher,” Mauad said in a press release from the Plastic Health Council, a group that advocates for reducing plastic use.

“What is worrying is the ability of such particles to be internalized by cells and change the way our body functions,” Mauad added.

The new study involved brain tissue from 15 routine autopsies performed on deceased residents of Sao Paulo, Brazil. The subjects ranged in age at death from 33 to 100 years (mean age 69.5 years).

“A total of 16 synthetic polymers [plastic] particles and fibers were identified” in the olfactory bulbs of the brains of 8 of the 15 people who died, the researchers report.

In almost 44% of cases, the plastic was polypropylene, one of the most common plastics used in everything from packaging to clothing and home accessories.

That suggests that “indoor environments are a significant source of inhaled microplastics,” the team said.

So how do these microscopic fragments enter the brain?

Amato-Lourenco and colleagues point out that nasal mucosa lying outside the brain can interact with cerebrospinal fluid, allowing microplastics to enter the olfactory bulb through small “perforations” in bone structures found in this area.

“So when you breathe through your nose, your olfactory nerve directly picks up particles and responds to the particles you breathe in as a direct sensory mechanism,” says Dr. Wells Brambl, core faculty in medical toxicology at Long Island Jewish Medical Center in New York. York city.

“The fact that there is no blood-brain barrier there leads to direct access to the brain, and most importantly, just above the olfactory nerve are the frontal and prefrontal lobes, where we believe the seat of consciousness is,” Brambl added to. who was not involved in the research.

Other studies have already shown that “environmental black carbon particles” from air pollution can be found in the olfactory bulb, and in rare cases small amoebae are also detected there that can cause a fatal form of encephalitis, the Brazilian researchers noted.

They said the new data “expands the idea that not only black carbon but also microplastics accumulate in the olfactory bulb of humans.”

Can these microplastics affect brain health? That is not yet clear, says Amato-Lourenco’s team, but the ‘potential’ is there.

“Given the potential neurotoxic effects caused by microplastics in the brain, and the widespread environmental contamination with plastics, our results should raise concerns in the context of the increasing prevalence of neurodegenerative diseases” such as Parkinson’s, ALS and other diseases, the researchers said .

“My intuition would say it’s not good to have plastic in your brain,” Brambl said. “However, data from long-term prospective studies have not yet been conducted. So it is impossible to draw definitive conclusions.”

Still, he said, “I think this study is very thought-provoking in the sense that we need to start looking at this as a real long-term public health problem.”

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