Microplastics Found in One of the Body’s Most Vital Organs

Plastic never truly disappears. Instead, it breaks down into increasingly smaller fragments, some so tiny that they can penetrate the body's protective barriers and accumulate within our tissues. These particles have already been detected in human blood, lung tissue, and even breast milk. Now, researchers from Sapienza University of Rome have searched for them in one of the body's most inaccessible locations—the blood vessels supplying the heart itself. Their findings were published in the European Heart Journal.

"Microplastics and nanoplastics are extremely small plastic particles that are found almost everywhere in the environment, including the air we breathe, the water we drink, and many of the foods we eat," said Pasquale Paolisso. "In recent years, scientists have begun detecting these particles in human tissues and organs, raising concerns about their potential effects on health."

The research team analyzed data from 61 patients who underwent coronary angiography at two Italian hospitals, according to Planet Today. Participants were divided into three groups based on the condition of their hearts.

One group had recently experienced a heart attack, another had chronic coronary artery disease, while the remaining participants had normal-looking coronary arteries.

Blood samples were collected directly from the vessels supplying the heart muscle at Sant'Andrea University Hospital in Rome. Additional samples were obtained at the University Hospital of Verona, while the plastic particles were analyzed at the University of Campania Luigi Vanvitelli in Naples.

Researchers also recorded whether participants smoked and estimated their exposure to air pollution over the previous two years.

The differences between the three groups were striking. Among patients who had suffered a heart attack, plastic particles were detected in 84% of cases.

The prevalence dropped to 40% among patients with chronic coronary artery disease and to 32% among individuals with normal coronary arteries.

Heart attack patients also carried a wider variety of plastic particles in their blood. The most common was polyethylene, a material widely used in shopping bags and food packaging.

Researchers suggest that the diversity of plastic types may be just as important as the quantity detected, since a wider range of plastics indicates exposure to multiple environmental sources throughout a person's lifetime.

Both smoking and air pollution had a significant impact on the findings. Patients with greater long-term exposure to polluted air were more likely to have microplastics in their blood.

Smokers showed the highest levels of exposure. They were six times more likely than non-smokers to have these particles circulating in their bloodstream.

The combination of smoking and heavy air pollution appeared particularly harmful. Every participant who both smoked and lived with high levels of air pollution had detectable plastic particles in their blood, compared with only 12.5% of participants exposed to neither factor.

Professor Emanuele Barbato of Sant'Andrea University Hospital emphasized that the study does not prove that microplastics cause heart attacks. However, it does reveal a strong association between environmental exposures, the presence of microplastics in the blood, and cardiovascular disease.

"Very little was previously known about whether these particles are present in the coronary circulation—the blood flowing through the arteries that supply the heart—or whether environmental factors such as smoking and air pollution influence their presence," Barbato said. "Our findings suggest that smoking may facilitate the entry of microplastics and nanoplastics into the bloodstream through the lungs. Air pollution may act in a similar way."

The lungs are considered a likely entry route for these particles. They may cross the thin barrier deep within lung tissue and enter the bloodstream—a pathway already well documented for soot and other airborne pollutants.

Once inside blood vessels, these particles may contribute to serious health problems. Laboratory studies have linked them to inflammation and damage to the delicate inner lining of arteries.

They have also been shown to trigger oxidative stress and damage mitochondria—the tiny energy-producing structures inside cells. Over time, these processes are known to contribute to the development of vascular disease.

Previous research has already identified plastic particles within fatty plaques that build up in the carotid arteries of the neck. Patients with these plaques were more likely to experience recurrent heart attacks and strokes during the following three years.

The presence of plastic in the bloodstream was also associated with higher levels of inflammation. In particular, researchers observed elevated concentrations of two inflammatory markers: tumor necrosis factor (TNF) and interleukin-6 (IL-6).

"Our findings highlight the need to consider microplastic pollution as part of the broader range of environmental factors affecting human health," Barbato concluded. "Policies aimed at reducing air pollution, tobacco smoke exposure, and plastic contamination may not only benefit the environment but could also improve cardiovascular health."