A study has detected microplastics in blood clots removed during surgeries from arteries in the heart, brain, and deep veins in the legs.
Although the study analyzed a smaller sample size—30 patients compared to the 257 participants monitored over 34 months in the earlier research—it provided insights aligning with previous findings. Similar to the Italian-led team’s observation that microplastics in arterial plaques correlated with increased risk of heart attacks and strokes, the Chinese research suggests a potential connection between microplastic levels in blood clots and disease severity.
The study examined clots removed from patients, aged an average of 65, following incidents of stroke, heart attack, or deep vein thrombosis. The patients came from diverse backgrounds, with varying health factors such as smoking, alcohol use, hypertension, and diabetes. Daily exposure to plastic products was also noted.
Chemical analysis detected microplastics in 24 of the 30 blood clots, identifying a range of shapes, sizes, and concentrations. Common plastics such as polyvinyl chloride (PVC), polyethylene (PE), and polyamide 66 were found, echoing the types observed in the arterial plaque study. PE, widely used in items like bottles and shopping bags, was the most prevalent, comprising 54 percent of detected particles.
Notably, higher microplastic levels in blood clots were associated with elevated D-dimer levels, a marker linked to blood clot formation and breakdown. This connection raises further concerns about the potential impact of microplastics on vascular health.
The findings underscore the importance of continued research into the environmental and health implications of microplastics.
D-dimer, a protein fragment released during the breakdown of blood clots, is typically absent in blood plasma. Elevated D-dimer levels in tests suggest the presence of clots, prompting researchers to consider whether microplastics could be contributing to increased clotting.
Further research is required to explore this possibility. As an observational study, this investigation did not measure microplastics in blood, limiting its conclusions to potential associations rather than definitive causes.
“These findings suggest that microplastics may serve as a potential risk factor associated with vascular health,” stated Tingting Wang, a clinician-scientist at the First Affiliated Hospital of Shantou University Medical College in China, alongside colleagues in the published paper.
“Future research with a larger sample size is urgently needed to identify the sources of exposure and validate the observed trends in the study.”
— Tingting Wang
Microplastics have already been detected in human lung tissue and blood samples, highlighting the ease with which microscopic plastic fragments can infiltrate the body. While the exact pathway remains unclear, their potential to accumulate in blood clots raises important health concerns.
Earlier research from 2023 revealed the chemical signatures of microplastics in 16 surgically removed blood clots. Wang and the research team have now advanced understanding by using infrared chemical imaging to examine how concentrated these particles can become in clots and their potential effects on health.
The pace of discoveries in this field is accelerating—from identifying microplastics in human tissues to exploring their effects in cells, animal models, and now within human health.
This work comes at a critical time, as global plastic production continues to rise. Fossil fuel companies are intensifying plastic output in response to declining prospects in other industries.
“Due to the ubiquity of microplastics in the environment and in everyday products, human exposure to MPs is unavoidable. As such, microplastic pollutants have sparked growing concern due to their widespread presence and potential health implications.”
– Tingting Wang
https://www.nejm.org/doi/10.1056/NEJMoa2309822
Summary
Background
Microplastic (MP) pollution has emerged as a significant environmental concern worldwide. While extensive research has focused on their presence in marine organisms and ecosystems, their potential impact on human health, particularly on the circulatory system, remains understudied. This project aimed to identify and quantify the mass concentrations, polymer types, and physical properties of MPs in human thrombi surgically retrieved from both arterial and venous systems at three anatomically distinct sites, namely, cerebral arteries in the brain, coronary arteries in the heart, and deep veins in the lower extremities. Furthermore, this study aimed to investigate the potential association between the levels of MPs and disease severity.
Methods
Thrombus samples were collected from 30 patients who underwent thrombectomy procedures due to ischaemic stroke (IS), myocardial infarction (MI), or deep vein thrombosis (DVT). Pyrolysis–gas chromatography mass spectrometry (Py-GC/MS) was employed to identify and quantify the mass concentrations of the MPs. Laser direct infrared (LDIR) spectroscopy and scanning electron microscopy (SEM) were used to analyse the physical properties of the MPs. Demographic and clinical information were also examined. A rigorous quality control system was used to eliminate potential environmental contamination.
Findings
MPs were detected by Py-GC/MS in 80% (24/30) of the thrombi obtained from patients with IS, MI, or DVT, with median concentrations of 61.75 μg/g, 141.80 μg/g, and 69.62 μg/g, respectively. Among the 10 target types of MP polymers, polyamide 66 (PA66), polyvinyl chloride (PVC), and polyethylene (PE) were identified. Further analyses suggested that higher concentrations of MPs may be associated with greater disease severity (adjusted β = 7.72, 95% CI: 2.01–13.43, p < 0.05). The level of D-dimer in the MP-detected group was significantly higher than that in the MP-undetected group (8.3 ± 1.5 μg/L vs 6.6 ± 0.5 μg/L, p < 0.001). Additionally, LDIR analysis showed that PE was dominant among the 15 types of identified MPs, accounting for 53.6% of all MPs, with a mean diameter of 35.6 μm. The shapes of the polymers detected using LDIR and SEM were found to be heterogeneous.
Interpretation
This study presents both qualitative and quantitative evidence of the presence of MPs, and their mass concentrations, polymer types, and physical properties in thrombotic diseases through the use of multimodal detection methods. Higher concentrations of MPs may be associated with increased disease severity. Future research with a larger sample size is urgently needed to identify the sources of exposure and validate the observed trends in the study.
