Micronanoplastics have been detected at significantly higher concentrations in the neck arteries of people with plaque buildup – particularly those who have experienced stroke, mini-stroke or temporary vision loss – according to preliminary research presented at the American Heart Association’s Vascular Discovery 2025 Scientific Sessions. The research builds on an Italian study published in 2024, which linked micronanoplastics in carotid plaque to poorer cardiovascular outcomes across a three year period.
After analyzing 48 carotid artery samples, researchers from the University of New Mexico and the Office of the Medical Investigator discovered that plastic levels in the plaques of symptomatic individuals were more than 50 times higher than in the artery walls of those without plaque. Participants included individuals undergoing surgery for carotid plaque removal and age-matched deceased donors without artery disease.
“These findings indicate that the biological effects of micronanoplastics on fatty deposits are more complex and nuanced than simply causing sudden inflammation,” commented Ross Clark, the study’s lead author, in a recent press release.
The team quantified micronanoplastics via pyrolysis gas chromatography-mass spectrometry, enabling plastic detection through thermal degradation. A shortcoming of this method, however, is that biological components such as lipids can produce pyrolysis products that mimic polymers such as polyethylene.
"We are constantly improving our method to reduce the amounts of lipids in the samples to lessen their impact on the results,” Clark noted. “Lipids have a very similar spectral signature on gas chromatography as some plastic polymers (in particular polyethylene). It can be challenging to distinguish between the lipids and the polyethylene in the results. That's why removing the lipids is so important.
In asymptomatic patients with plaque, plastic concentrations reached 895 micrograms per gram – about 16 times higher than in controls. In symptomatic patients, this figure rose to 2,888 micrograms per gram. The study found no link, however, between plastic levels and acute inflammatory markers such as TNF-α and IL-6. Instead, RNA sequencing suggested subtler biological effects such as changes in gene expression in plaque-stabilising stem cells and reduced activity in anti-inflammatory macrophage genes.
While the study presents a new potential target for stroke prevention, Clark emphasized the need for prudence, when interpreting the results moving forward. “It’s very important to study what these materials do to our bodies. However, we should be cautious about the early results of this study. We won’t fully understand the biological effects for many years to come,” he said.
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