Nanoparticles: How plastic particles get into the brain
One of the biggest environmental problems is invisible: tiny plastic particles, so-called micro- and nanoplastic particles (MNP), can be found everywhere in nature – worldwide: Expeditions have even tracked down microplastics in the arctic snow.
It also enters the human body through food, water and cosmetics. There, the particles are distributed everywhere – and also reach the brain.
This is protected from most pollutants by the so-called blood-brain barrier. However, researchers at MedUni Vienna have now discovered how the plastic particles manage to slip through the barrier.
Nanoparticles: In the brain within two hours
To do this, the team led by Prof. Lukas Kenner from the Clinical Institute of Pathology administered solutions with micro- and nanoplastic particles made of polystyrene to laboratory mice. Polystyrene is a common plastic used in food packaging, among other things.
Science refers to particles smaller than 0.001 millimetres as nanoplastics, while microplastics with 0.001 to 5 millimetres are sometimes still visible to the naked eye.
Subsequent autopsies of the animals revealed that the nanoparticles had migrated into the rodents’ brains within two hours.
Deposits favour the infiltration
Cholesterol, endogenous proteins and other biomolecules that are deposited on the surface of the particles play a decisive role. The researchers refer to these enveloping layers as “corona”.
While a cholesterol-containing corona promoted the migration of plastic particles into the brain, protein-rich deposits slowed down the passage through the blood-brain barrier.
Which substances accumulate depends in turn on which attachments the particles bring with them from the outside world. “Before entering the body, MNPs receive an environmental or eco-corona consisting of a variable composition of biomolecules, organic substances, and chemical and biological contaminants,” the researchers write.
Penetrability depends on the environment
The ability of the various particles to pass through therefore not only depends on the size of the particles, but also on the environment from which they originate. This must be taken into account when assessing health risks. “The type of corona can significantly affect the ability of the particles to cross the blood-brain barrier and their overall toxicity,” the scientists said.
This shows how important it is to understand the corona on the surface of plastic particles. “Given the widespread use of plastics in our daily lives and growing concerns about the impact of microplastics on the environment and our health, there is an urgent need for further research in this area,” the authors write.
Inflammation and immune responses?
Because the health risks for humans and the environment have not yet been researched. But there are first worrying indications: Micro- and nanoplastic particles, at least in the gastrointestinal tract, are associated with inflammatory and immune reactions and with the development of cancer.
“In the brain, plastic particles could increase the risk of inflammation, neurological disorders or even neurodegenerative diseases such as Alzheimer’s or Parkinson’s ,” says Kenner.
Better drink tap water!
The particles enter the food chain via decomposing and crushed packaging waste, among other things.
Not only solid foods but also liquids play a role: Anyone who drinks the recommended 1.5 to 2 litres of water per day from plastic bottles consumes around 90,000 plastic particles per year in this way alone.
However, tap water is no longer free of microplastics. After all, anyone who drinks tap water can reduce the amount absorbed to 40,000 particles a year, depending on their geographical location.
In the UAE bottles of water are a must for most people, but few recognise that these cheap disposable PET1 type plastic bottles have been proven to leach particles into the water, so would appear that adopting more environmentally friendly practices of using refillable and reusable PET2 type containers for dispensing and drinking water are better for the planet and for your health.