Brain health: Nanoplastics linked to Parkinson's disease and dementia

  • Researchers from Duke University School of Medicine have found nanoplastics affect a specific protein found in the brain, causing changes linked to Parkinson’s disease and other types of dementia.
  • Over 10 million people around the world have Parkinson’s disease.
  • Scientists know that genetics, lifestyle influences, and environmental factors play a role in disease development.

Researchers from Duke University School of Medicine found that nanoplastics — extremely small particles of plastics left to break down in the environment that can leach into water and soil — affect a specific protein found in the brain, causing changes linked to Parkinson’s disease and other types of dementia.

The study was recently published in the journal Science Advances.

Parkinson’s disease is considered the fastest-growing neurological condition in the world. Researchers estimate that more than 10 million people globally live with the condition.

There is currently no cure for Parkinson’s disease. While scientists are still not sure what exactly causes the condition, they do know that genetics, lifestyle influences, and environmental factors play a role.

How environmental factors affect Parkinson’s disease 

According to Dr. Andrew West, professor in the Department of Pharmacology and Cancer Biology at Duke University School of Medicine and principal investigator of this study, we know that Parkinson’s disease is not typically heritable or transmissible, and some of the disease risk is thought to be due to pesticide and toxin exposures in the environment.

“However, the known environmental risks account for a very small percentage of what may be lurking out there, increasing our risk of getting sick,” Dr. West told Medical News Today. “When we have identified a bonafide risk for disease, or risks for progression of (the) disease, in the environment, we can take steps to protect ourselves from those risks.”

Dr. West explained he and his team were initially using different types of nanoparticles to facilitate biomarker assays for the diagnosis of Parkinson’s disease and dementia. By chance, they noticed that some types of nanoparticles had a tremendous effect on aggregating a protein known as alpha-synuclein that is linked to brain diseases.

“Though the nanoplastics did not have a beneficial effect in the biomarker assays because they could aggregate the proteins without any samples from patients, we decided to follow up the unexpected interactions since these types of nanoparticles bear some similarities to those beginning to accumulate in the environment.”

– Dr. Andrew West

Nanoplastics may interact with a protein in the brain

For this study, scientists used three models — test tubes, cultured neurons, and a mouse model of Parkinson’s disease — to conduct their research.

Dr. West and his team found that nanoparticles of the plastic polystyrene — used to make foam packaging peanuts, egg cartons, and disposable drinking cups — draw the alpha-synuclein protein, causing it to accumulate.

“In different types of assays, we found that nanoplastics might hijack parts of the alpha-synuclein protein that normally bind to lipids in the brain, and twist the protein into a form that may encourage aggregation associated with disease,” Dr. West detailed.

“However, the problems do not stop there, since the plastics might impair the very machinery designed to destroy aggregates that form a part of the cell called the lysosome. We suspect this ‘two-hit’ mechanism is behind the interactions we found in the model,” Dr. West added.

How nanoplastics affect brain and overall health

When plastic breaks down in the environment, it first turns into small particles called microplastics. From there, the microplastics continue to degrade, forming nanoplastics.

A study published in March 2022 found on average, people consume about 5 grams of microplastic and nanoplastic in their gastrointestinal tract every week.

Previous research shows both microplastics and nanoplastics can be harmful to a person’s overall health.

For example, research has found that nanoplastics can also disrupt the regular processes of lung and liver cells and may be linked to certain types of cancer.

This is also not the first study to examine a link between nanoplastics and brain health. Research published in June 2020 discovered that exposure to micro- and nanoplastics can negatively impact the brain, leaving it open to developing neuronal disorders.

A study published in April 2023 discovered that nanoplastic consumption led to reduced cognition and short-term memory in mice.

Why monitoring plastic pollution is important

Dr. West said he thinks this research provides a compelling reason to develop technology to monitor plastic pollution as it might accumulate in the human brain and then to monitor different people with different exposures in how they might be susceptible to Parkinson’s disease and other neurological problems.

“If we knew the specific molecular nature of particularly bad nanoplastic actors, we could develop policies and technologies to make sure they don’t end up in our food and water.”

– Dr. Andrew West

As for the next steps in this research, Dr. West said they would like to run longer-term experiments with chronic dosing to help determine how different types of nanoplastics affect different molecular processes that scientists think drive disease risk and progression.

“We also need to have a better idea of what lifetime exposures to different types of nanoplastics look like so that our models in the lab are more informative,” he added.

More insights into what may cause neurodegenerative diseases

MNT also spoke about this study with Dr. Rocco DiPaola, neurologist and director of the Movement Disorder Program at Hackensack Meridian Neuroscience Institute at Jersey Shore University Medical Center.

Dr. DiPaola said this research may be another piece of the puzzle as to the causation of Parkinson’s disease and other alpha-synuclein-related disorders:

“It has long been suspected that genetic factors in combination with an environmental trigger play a major role in the development of these disorders.

It is an additional potential causative agent for these diseases. Environmental factors (are) likely one of multiple factors that play a major role in the development of Parkinson’s disease”

When asked how readers can protect themselves from environmental factors that may increase their risk for Parkinson’s disease and other types of dementia, Dr. DiPaola said while there is no way to mitigate all risks, limiting exposure to toxins, such as pesticides, would be one means to limit risk.

“Prior environmental studies have determined increased risk with exposure to pesticides, growing up in a rural environment, and exposure to well water,” he added.

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