Could microplastics be linked to cardiovascular disease?

An alarming study has found that people who suffer a serious heart attack are more likely to have micro and nanoplastics (MNPs) in their blood, adding to evidence that environmental pollution may be affecting cardiovascular health.

A paper on the small observational study, published in the European Heart Journal, showed that people with a form of heart attack known as ST elevation myocardial infarction (STEMI) who underwent procedures like coronary angiography had higher levels of MNPs in their blood compared with people undergoing coronary angiography for confirmed chronic coronary artery disease (CAD), as well as people with no evidence of CAD.

While the study is exploratory, involving only 61 patients, it raises the possibility that exposure to MNPs – levels of which are rising globally across environmental and biological systems – has health implications.

"Micro and nanoplastics are tiny plastic particles that are found virtually everywhere in the environment, including the air we breathe, the water we drink, and many foods we consume," said Pasquale Paolisso of Sant'Andrea Hospital Sapienza University of Rome, Italy, who is the lead author of the study.

"In recent years, scientists have begun to detect these particles in human tissues and organs, raising concerns about their potential health effect," he added. "However, very little was known about whether these particles are present in the coronary circulation […] or whether environmental exposures such as smoking and air pollution might influence their presence."

The analysis showed that people who smoke and people exposed to higher levels of air pollution had higher levels of MNPs in their blood.

Among those who had a STEMI, MNPs were detected in 84% of patients, compared with 40% of patients with CAD and 32% of patients without CAD. The heart attack patients also had a greater variety of plastic types in their blood, and the presence of MNPs was often accompanied by elevated inflammatory biomarkers.

The most common type of plastic was polyethylene, which is commonly used in packaging and consumer products, and accounted for 97% of all particles.

"These findings do not prove that microplastics cause heart attacks, but they reveal a strong association between environmental exposures, microplastics in the blood, and cardiovascular disease," said Emanuele Barbato, a co-author from Sapienza University of Rome.

Commenting on the study, cardiology specialist Prof Alun Hughes of University College London (UCL), pointed out that it remains possible that high levels of MNPs in people with heart attacks could reflect some other factor, such as social deprivation, that could increase exposure to the particles and raise the risk of heart attack.

He also noted that patients treated at hospital for a heart attack receive intravenous infusions that have been shown to shed microplastics into the blood, which could also be a credible reason for the differences.

"The authors clearly state that 'these findings should be interpreted as exploratory and hypothesis-generating, rather than as definitive or confirmatory risk estimate'," said Hughes. "Readers should bear this caution in mind and not jump to assuming a cause-effect relationship."

That view was echoed by Dr Vahitha Abdul Salam, a vascular pharmacologist at Queen Mary University of London (QMUL), who said: "Overall, the findings strengthen the growing body of evidence linking environmental exposures with cardiovascular disease, but larger prospective studies and mechanistic investigations will be needed before conclusions can be drawn about causality or clinical risk."

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