Microplastics Discovered in Human Arteries: A Hidden Threat to Cardiovascular Health
In a groundbreaking study conducted at a hospital in Naples, surgeons performed carotid endarterectomies on 257 patients, meticulously removing fatty plaques obstructing blood flow to the brain. When researchers examined these plaques under an electron microscope, they uncovered an alarming and unexpected presence: jagged fragments of polyethylene and polyvinyl chloride (PVC), common plastics found in everyday items such as shopping bags, food packaging, and PVC pipes. These plastic particles were embedded within the arterial walls of 150 patients—approximately 58% of the cohort.
Over the following 34 months, these patients with microplastics in their plaques were 4.5 times more likely to experience major cardiovascular events, including heart attacks, strokes, or death, compared to patients whose plaques were free of plastic. Published in the New England Journal of Medicine in March 2024, this study has sparked intense debate among cardiologists and researchers worldwide about the implications of microplastic exposure on human cardiovascular health.
Unexpected Prevalence and Impact
Raffaele Marfella and his research team at the University of Campania initially aimed to detect microplastic contamination in carotid artery plaques, motivated by rising reports of microplastics in oceans, soil, and even human blood. While they anticipated some degree of contamination, the discovery that over half of the patients harbored microplastics was startling.
The follow-up clinical data revealed a stark contrast: among the 150 patients with plastic-laden plaques, 30 suffered a heart attack, non-fatal stroke, or died within 34 months. Conversely, only eight of the 107 patients with clean plaques experienced such outcomes. This translated to a hazard ratio of 4.53, a statistically significant effect after adjusting for conventional cardiovascular risk factors such as age, sex, smoking status, diabetes, cholesterol levels, and blood pressure.
In cardiology, a risk factor with such a magnitude typically aligns with well-established contributors like uncontrolled hypertension or a family history of early coronary artery disease, underscoring the potential seriousness of microplastic inclusion in arterial plaque.
How Microplastics May Worsen Atherosclerosis
The biological mechanism linking microplastics to atherosclerosis appears consistent with the known progression of the disease. Atherosclerosis begins with endothelial damage—a dysfunction of the single-cell lining separating blood from vessel walls. Low-density lipoprotein (LDL) particles infiltrate the endothelium, oxidize, and attract monocytes that mature into macrophages. These macrophages consume lipids, becoming foam cells, which eventually die and contribute to a necrotic core within the plaque. A fibrous cap forms over this core, but when it weakens and ruptures, it triggers blood clots responsible for heart attacks and strokes.
Micro- and nanoplastic particles, due to their minuscule size, can permeate the endothelium similarly to LDL. Once lodged in the arterial intima, they appear to amplify inflammation by recruiting additional macrophages, increasing foam cell death, and thinning the fibrous cap. Marfella’s team documented elevated inflammatory markers—interleukin-18 and tumor necrosis factor-alpha—in patients with microplastics, both known to destabilize arterial walls.
Importantly, microplastics do not initiate atherosclerosis but seem to accelerate the progression of an existing disease process, potentially transforming stable plaques into vulnerable ones prone to rupture.
Reproducibility Beyond Naples
Replication of these findings is essential for establishing scientific consensus. In April 2025, Ross Clark, a vascular surgeon-scientist at the University of New Mexico, presented complementary data at the American Heart Association’s Vascular Discovery Scientific Sessions. His smaller cohort study (<50 patients) compared carotid artery samples from healthy individuals, asymptomatic plaque carriers, and symptomatic patients who had experienced strokes or transient ischemic attacks.
Clark’s team found a dramatic gradient: symptomatic patients’ plaque contained roughly 51 times more micronanoplastic material than healthy controls, with asymptomatic patients showing intermediate levels. This striking association reinforces the potential link between plastic accumulation and disease severity.
Karen Furie, chair of neurology at Brown University’s Warren Alpert Medical School, highlighted that plastic exposure has not been traditionally recognized as a modifiable stroke risk factor and suggested this area warrants further research into preventative strategies. However, Clark urged caution, noting the technical challenges in accurately distinguishing plastic particles from lipid signatures in tissue using pyrolysis gas chromatography-mass spectrometry, the analytical method employed by his team.
Understanding Microplastic Exposure
Earlier estimates, such as the 2019 WWF-commissioned study suggesting an average ingestion of 5 grams of plastic per week (comparable to the weight of a credit card), have faced scrutiny and revision. Nevertheless, the presence of microplastics in human biological tissues is well-documented, including blood, breast milk, placenta, testicular tissue, and recently, brain tissue.
A February 2026 study reported microplastics in nine out of ten prostate cancer tumors examined, with higher concentrations in malignant versus adjacent healthy tissue. While causality remains unproven, the repeated detection of plastics preferentially accumulating in diseased tissues across multiple organ systems has propelled further investigations and funding.
Clark emphasized that microplastics are not merely introduced through direct contact with plastic items but are pervasive contaminants already present in food and water supplies before packaging.
Implications for Cardiology
Cardiovascular disease remains the leading cause of mortality globally, with decades of research identifying modifiable risk factors such as smoking, elevated LDL cholesterol, hypertension, diabetes, obesity, and sedentary lifestyle. Each has guided effective interventions.
The introduction of microplastic exposure as a potential new risk factor with a hazard ratio exceeding 4 is profound. It challenges existing paradigms and demands urgent attention. However, unlike traditional risk factors, no clear clinical interventions exist yet. Reducing plastic exposure is complicated by the absence of binding international agreements limiting plastic production, with much emphasis placed on recycling and waste management rather than upstream prevention. Meanwhile, arterial plaques with embedded plastics continue to form.
From Association to Causation: The Scientific Challenge
Despite compelling data, the scientific community recognizes that association does not equate to causation. Marfella’s team and subsequent researchers acknowledge the limitations inherent in single-center studies with modest sample sizes. There remains the possibility that microplastics are biomarkers of another harmful exposure rather than the direct cause of increased cardiovascular events.
Historically, plastics were presumed inert in the human body, passing through without biological impact. This assumption lacked rigorous evidence and is now being rigorously tested through tissue analyses that consistently detect plastic fragments embedded in diseased tissues.
This evolving narrative parallels other scientific fields where previously overlooked environmental factors have emerged as significant health influencers, reshaping risk assessment frameworks.
Looking Ahead: Research and Clinical Implications
The Naples study has catalyzed a wave of ongoing research globally. The University of Campania is expanding its prospective cohort, while Clark’s team investigates immune responses, particularly macrophage activity in plaques with varying plastic burdens. Additional studies are underway in South Korea, Germany, and the Netherlands, employing improved methodologies to clarify the presence and impact of microplastics in arterial tissues.
Longitudinal follow-up of the Naples patients will extend to five and ten years, determining whether the elevated hazard ratio persists. Should these findings be confirmed, micro- and nanoplastic exposure could be formally recognized as a significant cardiovascular risk factor, reshaping prevention and treatment strategies. Alternatively, if confounding factors or measurement artifacts are identified, the field may recalibrate accordingly.
Regardless of future outcomes, the presence of plastic particles embedded within the arteries of hundreds of patients is a sobering reality—one that calls for heightened awareness, rigorous scientific inquiry, and possibly, public health interventions.
For more detailed information and references, read the full report Here.
