Potentially ground-breaking research from a Trinity College Dublin (TCD) team has shown that tiny pieces of plastic can damage our brains, and may be a factor in rising levels of Alzheimer’s and Parkinson’s disease.
The study, led by Associate Professor of Biochemistry at TCD, Gavin Davey, and published in the Journal of Hazardous Materials: Plastics, was conceived of by student Devin Seward, Prof Davey said.
The research looked at whether miniscule nanoplastics, derived from the breakdown of environmental plastics, caused degeneration in the brain, on the basis that these tiny particles – thousands of times smaller than a human hair – have been detected in multiple tissues including the brain, raising concerns over their potential neurotoxicity.
Speaking to Morning Ireland, Prof Davey said that his team looked at how nanoplastics might be affecting mitochondria, the organelles inside each cell that make energy for that cell, in a way that caused dysfunction leading brain disease.
He said that the number of cases of Parkinson’s Disease had doubled in the past few decades, and that causes of the disease was “mainly sporadic and environmental”, and that plastics might be a mechanism in how the disease developed.
He explained that these nanoplastics – a thousandth of a millimeter in diameter – were being inhaled and imbibed constantly, especially in urban areas, and that these “will cross the blood-brain barrier and get into our brain, and that’s been shown in post-mortem studies.”
Prof Davey said that nanoplastics were found in hard plastic containers, food containers, plastics surrounding food, plastics in fast food containers – and to “especially avoid” heating up tea or coffee in foam cups. He also said he not recommend drinking water from plastic bottles.
The study said that “plastic pollution is a global environmental crisis, with over 400 million tonnes of plastic being produced annually, much of which fragments into microplastics and nanoplastics in the environment”.
“Adult humans have been suggested to have a median intake of 883 particles/capita/day resulting in a lifetime accumulation of up to 40.7 ng/capita of microplastics,” it noted.
Using rat brain tissue in the laboratory, the Trinity College team said they found “compelling evidence” that nanoplastics impaired the ability of mitochondria to produce vital energy from oxygen. The tiny plastic particles impacted the electron transport chain, a key part of the energy production process for mitochondria.
The study found that mechanism of nanoplastics toxicity in brain mitochondria is localised to the transfer of electrons in the electron transport chain. The ability of nanoplastics “to cause mitochondrial dysfunction and brain energy metabolism indicates their potential as a toxic factor in neurodegenerative disorders”, the researchers concluded.
The study found that the disruption was consistently observed in both synaptic and non-synaptic mitochondria, though synaptic mitochondria showed higher sensitivity at peak concentrations, consistent with their well-established vulnerability in ageing and neurodegenerative diseases.
Prof Davey said that reducing unnecessary plastic packaging is a logical step, and that follow-up research would examine the ability of different types of nanoplastics to cross the blood-brain barrier.
“We want to find out which are the most potent and how we might protect the brain,” he told the Irish Times, adding that “restricting exposure is key”.