More microplastics and nanoplastics have been found in the coronary circulation of patients experiencing ST-elevation myocardial infarctions (STEMIs) compared with blood from healthy coronary arteries or those with chronic coronary syndromes.

The tiny plastic particles, smaller than 5 mm, are found throughout the environment and can be inhaled or ingested into the body, but previous evidence on their health risks remained inconclusive. A new study, published in the European Heart Journal, included 61 adults, 19 of whom experienced STEMI, who were treated at hospitals in Italy. Researchers collected separate blood samples from vessels supplying the heart and limbs, and they estimated air pollution exposure via home addresses.

Microplastics and nanoplastics were detected in 84% of patients with STEMI, who also showed a broader array of plastic types compared with 40% of patients with chronic coronary syndromes and 32% of those with healthy coronary arteries. Samples with more microplastics also had elevated tumor necrosis factor α (TNF-α) and interleukin-6, suggesting an inflammatory response, according to researchers.

People who smoked were more likely to have microplastics in their blood than those who did not. Researchers also detected microplastics in all people with higher pollution exposure who smoked, in contrast with 12.5% of people who didn’t smoke with lower exposure. Researchers noted these findings demonstrate a link among environmental exposures, bloodstream microplastics, and heart disease, but they “do not prove that microplastics cause heart attacks,” the lead author concluded in a news release.

Bron: Jama /  September 11, 2026