Plastic used in food packaging found in brain two hours after ingestion

“In the brain, plastic particles could increase the risk of inflammation, neurological disorders, or even neurodegenerative diseases such as Alzheimer’s or Parkinson’s,” said Lukas Kenner, lead author of the study, in a press release.

The study was carried out in an animal model 

The researchers conducted their study on six mice, three of which were orally administered polystyrene. They euthanized the mice two to four hours after ingestion, allowing the team to harvest their brains and test for the presence of plastic.

The team found that the MNPs had crossed the blood-brain barrier and were present in the mice's brains. These plastic particles can increase the risk of neuroinflammation and neurodegeneration, as has been observed in previous studies. 

Our intestine has a similar protective wall. MNPs can enter the body and cross the intestine’s impermeable barriers as well. How these particles are carried over through these barriers is a complex process that depends on factors such as particle size, surface chemistry, and the type of cell with which they interact.

"To minimise the potential harm of micro- and nanoplastic particles to humans and the environment, it is crucial to limit exposure and restrict their use while further research is carried out into the effects of MNPs," Kenner said.

Study Abstract:

Humans are continuously exposed to polymeric materials such as in textiles, car tires and packaging. Unfortunately, their break down products pollute our environment, leading to widespread contamination with micro- and nanoplastics (MNPs). The blood–brain barrier (BBB) is an important biological barrier that protects the brain from harmful substances. In our study we performed short term uptake studies in mice with orally administered polystyrene micro-/nanoparticles (9.55 µm, 1.14 µm, 0.293 µm). We show that nanometer sized particles—but not bigger particles—reach the brain within only 2 h after gavage. To understand the transport mechanism, we performed coarse-grained molecular dynamics simulations on the interaction of DOPC bilayers with a polystyrene nanoparticle in the presence and absence of various coronae. We found that the composition of the biomolecular corona surrounding the plastic particles was critical for passage through the BBB. Cholesterol molecules enhanced the uptake of these contaminants into the membrane of the BBB, whereas the protein model inhibited it. These opposing effects could explain the passive transport of the particles into the brain.