Nanoplastics in the brain may promote Parkinson’s disease

With mounting evidence that tiny nanoplastic particles are in our bodies has come growing concern over the potential health impacts, and now a new study finds a link between nanoplastics in the brain and a higher risk for Parkinson’s disease.

Nanoparticles arise when the chemical polymers used in plastic packaging, textiles, single-use drinking cups and countless other products break down into small pieces. These particles can enter the bloodstream and cross the blood-brain barrier, with European researchers reporting earlier this year that in animal models, it can take two hours or less for certain nanoparticles to reach the brain after being ingested.

In humans, it’s long been thought that environmental factors play a role in Parkinson’s disease but specific causes are still unclear. The new study from the Duke University School of Medicine, published in the journal Science Advances, details how particles of polystyrene trigger chemical changes in the brain that can, in turn, make Parkinson’s and related types of dementia more likely.

That’s because the polysterene attracts a protein called alpha-synuclein, known to play a role in Parkinson’s and related dementia disorders. In lab and animal studies, the plastic’s interaction with α-synuclein leads to accumulations in the affected neurons in the brain. This mechanism appears linked to favorable conditions in which dementia diseases can develop.

The study authors note that Parkinson’s disease existed long before nanoplastics emerged in the environment, but they think that this “polysterene pollution in the human brain” may prove a new toxin. It adds to disease risks that depend on lifetime exposure levels, genetic interaction and other factors that need more study.

Further, the Duke team led by Dr. Andrew West say they chose the polysterene because it is now known to enter the blood and cross the blood-brain barrier in humans. But “other types of pervasive plastic waste, such as polyethylenes, polycarbonates, or polypropylene,” also warrant careful study.

West and the Duke investigators note that Parkinson’s disease is among the fastest growing neurological conditions in the world, even as the staggering amount of plastic pollution builds across the planet. This is expected to continue for the foreseeable future, with old plastics degraded by ultraviolet rays and broken down by mechanical weathering.

But if scientists can understand what’s at work, people can take steps to protect themselves from health risks that may include cancer and autoimmune disorders, as well as Parkinson’s and dementia-related disease.

“The technology needed to monitor nanoplastics is still at the earliest possible stages and not ready yet to answer all the questions we have,” West said. “But hopefully efforts in this area will increase rapidly, as we see what these particles can do in our models.”