Plastic never truly disappears. It simply breaks down into smaller and smaller fragments, some of which are so minute that they can cross the body’s protective barriers and settle within us. These remnants have already been detected in human blood, lung tissue, and even breast milk. A research team from Sapienza University of Rome set out to locate them in one of the most inaccessible places—the blood vessels of the heart itself. The study’s findings have been published in the European Heart Journal.
“Micro- and nanoplastics represent tiny plastic particles found almost everywhere in our surroundings, including the air we breathe, the water we drink, and many foods we eat,” said Pasquale Paolisso. “In recent years, scientists have started identifying these particles in human tissues and organs, raising concerns about their potential health effects.”
The research group analyzed data from 61 patients undergoing coronary angiography at two Italian hospitals. Each patient was categorized according to the condition of their heart.
One group had recently suffered a heart attack. Another group had chronic ischemic heart disease, while the rest had completely normal coronary arteries.
Blood samples were collected at Sant’Andrea University Hospital in Rome, taken directly from the vessels supplying the heart muscle. A second collection site was the university hospital affiliated with the University of Verona. The plastic particles themselves were then measured at the University of Campania Luigi Vanvitelli in Naples.
The researchers also recorded smoking habits and the amount of polluted air each patient had inhaled over the previous two years. The differences among the three groups were striking. Among those who had experienced a heart attack, plastic particles were found in 84% of cases.
This proportion dropped to 40% in patients with chronic ischemic heart disease. Only 32% of individuals with normal arteries had any plastic present. Those who had suffered a heart attack also exhibited a greater variety of plastic types in their blood. The most common was polyethylene, a material used in everyday items like shopping bags and food packaging.
The diversity of plastic types may be as significant as the numbers themselves. A wider range of plastic types points to more sources of daily exposure over a person’s lifetime.
Both smoking and air pollution had a clear impact on the results. Patients exposed to higher and longer-lasting levels of polluted air were more likely to have microplastics detected in their blood. Smokers fared the worst. Their likelihood of having these particles circulating in their bodies was six times higher than that of non-smokers.
The combination of these two factors caused even greater harm. Every patient who both smoked and breathed heavily polluted air had plastic in their blood, whereas among those with neither factor, this was true for only 12.5%.
Professor Emanuele Barbato from Sant’Andrea University Hospital stated that the study does not prove microplastics cause heart attacks, but it reveals a strong connection between environmental exposure, the presence of microplastics in the blood, and cardiovascular disease.
“However, very little was known about whether these particles are present in coronary circulation—the blood flowing through the arteries that supply the heart—or whether environmental factors like smoking and air pollution could influence their presence,” noted Barbato. “Our findings suggest that smoking may facilitate the entry of micro- and nanoplastics into the bloodstream through the lungs. Air pollution might work in a similar way.”
The lungs appear to be a likely route for these particles to enter. They can cross a thin barrier deep in lung tissue and enter the bloodstream—a pathway long studied for soot and other airborne pollutants.
Once inside a blood vessel, these particles can trigger serious issues. Laboratory studies have linked them to inflammation and damage to the delicate inner lining of arteries.
They also induce oxidative stress and harm the tiny energy powerhouses within our cells—the mitochondria. Over time, these same processes lead to the development of disease in healthy arteries.
Previous research has already identified plastic inside fatty plaques that accumulate in the neck’s arteries. Patients with these deposits experienced repeated heart attacks and strokes over the following three years. Among patients, the presence of plastic in the blood was associated with higher levels of inflammation. Specifically, two markers increased: tumor necrosis factor and interleukin-6.
“These results highlight the need to consider microplastic pollution as part of a broader range of environmental factors affecting health,” added Barbato. “Policies aimed at reducing air pollution, exposure to tobacco smoke, and plastic contamination could benefit not only environmental protection but potentially improve cardiovascular health as well.”
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