New research presented at the American Heart Association's Vascular Discovery 2025 Scientific Sessions suggested that carotid artery plaque may contain up to 51-fold higher levels of micronanoplastics compared with healthy arterial tissue, potentially introducing a novel target for stroke prevention.
In a small study involving 48 human carotid artery samples collected between 2023 and 2024, investigators found that micronanoplastic (MNP) concentrations were higher in arteries with plaque. Specifically, MNP levels were:
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895 µg/g in plaque from individuals without symptoms
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2,888 µg/g in plaque from individuals with symptoms (eg, stroke, transient ischemic attack, or transient vision loss)
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Compared with 57 µg/g in healthy arteries from age-matched deceased tissue donors.
“These types of plastics are commonly found in the environment, especially in ocean garbage patches,” said lead study author Ross Clark, MD, MBA, RPVI, a vascular surgeon-scientist at the University of New Mexico in Albuquerque. “Over many years, these plastics break down, mix into the soil and water, and can build up in the food chain. Many people think they mainly come from using plastic utensils, cutting boards, and water bottles. However, the main source is the food and water we eat and drink.”
Molecular and Immune Findings
The investigators also reported no evidence linking MNP burden to markers of acute inflammation in plaque. However, differential gene expression was observed in plaque-stabilizing cells and in macrophages, with reduced activity noted in anti-inflammatory genes.
“These findings indicate that the biological effects of [MNPs] on atherosclerotic plaque are more complex and nuanced than simply causing sudden inflammation,” Dr. Clark said. He added that future research will examine the immunological impacts of MNPs in atherosclerosis.
Methodological Considerations
MNP quantification was performed using pyrolysis gas chromatography–mass spectrometry. The investigators acknowledged that this method may not clearly distinguish between lipid degradation products and polyethylene, potentially affecting the measurements. Efforts to reduce lipid contamination in the analysis are ongoing.
“We believe our methods are currently the best way to address this specific criticism,” Dr. Clark noted.
Clinical Context and Commentary
Karen L. Furie, MD, MPH, FAHA, Vice Chair of the American Heart Association Stroke Brain Health Science Subcommittee and Chair of Neurology at the Warren Alpert Medical School of Brown University, who was not involved in the study, commented:
“This is a very interesting and troubling study. To date, we have not considered exposure to plastic [MNPs] a modifiable risk factor for stroke. Although it is important to understand the mechanism at play in the pathophysiology of symptomatic carotid atherosclerosis, this association presents a novel potential target for stroke prevention.”
This work builds on research published in 2024 by investigators in Italy, which found that the presence of MNPs in carotid plaque was associated with an increased risk of mortality and nonfatal cardiovascular events during a nearly 3-year follow-up period after surgery.
