For the first occasion, researchers have discerned the presence of infinitesimal microplastics embedded within the human cerebrum.
In a collaborative effort between scientists from Germany and Brazil, findings revealed that 8 out of 15 postmortem examinations of adults displayed microplastics infiltrating the olfactory bulb, a critical hub for the sense of smell.
These particles were likely inhaled over a lifetime, as microplastics are omnipresent in the atmosphere, according to HealthDay News.
Though microplastics have been previously identified in human pulmonary tissues, gastrointestinal tracts, hepatic systems, circulatory systems, and even in reproductive fluids, it was long assumed that the brain’s protective blood-brain barrier would prevent such foreign invaders from reaching cerebral tissues.
However, this groundbreaking study proposes an “avenue for microplastics’ translocation into the brain” through the olfactory bulb, as highlighted by lead researchers Luis Fernando Amato-Lourenco from the Free University Berlin, and Thais Mauad, an associate professor at the University of São Paulo’s pathology department.
Their findings were disseminated on September 16th via the JAMA Network Open journal.
Mauad, in a statement released by the Plastic Health Council—a body promoting reduced plastic utilization and a financier of this study—expressed concern: “With nanoplastics entering the body with even greater facility, the aggregate level of plastic particles could be significantly higher than anticipated.”
“What raises alarm is the potential of these particles to be internalized by cellular structures and influence the body’s intrinsic functions,” Mauad elaborated.
The study entailed an examination of brain matter from 15 individuals who had undergone standard autopsies in São Paulo, Brazil. These subjects ranged in age from 33 to 100, with an average age of 69.5 years at the time of death.
According to the researchers, “16 synthetic polymer particulates and fibers were detected within the olfactory bulbs of 8 of the 15 individuals,” as reported by HealthDay.
In approximately 44% of cases, the plastic identified was polypropylene—an exceedingly common material used in products ranging from packaging to apparel and household goods.
This observation suggests that “indoor environments serve as a significant source of inhaled microplastics,” according to the team’s report.
But how exactly are these minuscule fragments navigating their way into the brain?
Amato-Lourenco and his team hypothesize that the nasal mucosa, located outside the brain, may interact with cerebrospinal fluid, thereby allowing the entry of microplastics into the olfactory bulb via microscopic “perforations” in the surrounding bony framework.
“When one inhales through the nasal passages, the olfactory nerve samples airborne particles directly, reacting to the foreign entities as part of a sensory mechanism,” remarked Dr. Wells Brambl, a core faculty member in medical toxicology at Long Island Jewish Medical Center, who was not involved in the study.
He added, “Given that there is no blood-brain barrier in that region, there exists direct access to the brain. What’s particularly concerning is that the frontal and prefrontal lobes, thought to be the locus of consciousness, reside just above the olfactory nerve.”
Previous studies have already identified the presence of “environmental black carbon particles” from pollution in the olfactory bulb, and, in rare instances, amoebae capable of causing fatal encephalitis have also been detected in that region, the Brazilian researchers noted, according to the reports by HealthDay.
This latest data “broadens the scope of understanding, suggesting that not only black carbon but also microplastics accumulate in the olfactory bulb in humans.”
Could these microplastics have a tangible impact on brain health? That remains uncertain, according to Amato-Lourenco’s team, though the potential risks cannot be discounted.
“Given the neurotoxic implications of microplastics in the brain and the pervasiveness of environmental plastic contamination, our findings should raise significant concerns about the increasing incidence of neurodegenerative conditions,” including Parkinson’s disease, ALS, and other disorders, the researchers suggested.
“My instinct would indicate that having plastic particulates embedded in one’s brain is not advantageous,” Brambl opined. “However, long-term, prospective studies are still necessary. At present, it is impossible to draw definitive conclusions.”
Nevertheless, he emphasized, “This study is deeply provocative, urging us to contemplate this as a pressing public health issue that requires long-term attention.”