Scientists from the University of Hull and Hull York Medical School have discovered microplastics in vascular tissue for the first time, suggesting that the substances can pass to human tissue through blood vessels. Two of the most prominent polymer types that were found in vascular tissue during the study are used in food packaging.

The present study is the first to examine whether microplastics can infiltrate or cross any biological barrier, including blood vessels. Hull researchers, in collaboration with scientists from the Hull University Teaching Hospitals National Health Service (NHS) Trust, analyzed human saphenous vein tissue taken from patients undergoing heart bypass surgery.

Scientists found 15 microplastic particles per gram of vein tissue, which is a level similar to or higher than those reported for colon and lung tissues. Although the human health impacts are not yet known, Hull researchers point to studies using lab-grown cells suggesting that the presence of microplastics in human tissues may lead to inflammation and stress responses.

A total of five different polymer types were found in the vascular tissue, two of which—Polyvinyl acetate (PVAC) and Nylon/EVOH-EVA—are used in food contact applications.

The researchers call for further research into whether the presence of microplastics in human veins may damage the inside of the vein, leading to blockages over time. Additionally, the scientists stress the need to identify possible methods of removing microplastics from human tissues.