Undiseased and Diseased Abdominal Aortas Contain Environmentally Relevant Micronanoplastics

Background Plastics production has accelerated, with most products ultimately residing in the environment. Plastics degrade into micro (<5 mm) and nano (<1000 nm) plastic particles (MNP) that can be ingested or inhaled by humans. In prior literature, MNPs have been found in higher concentrations in diseased arteries, but mechanisms remain obscure. Studies have shown MNPs in tissue from ascending aortic dissections, but data on infrarenal aortic aneurysms, occlusive plaques, and cadaveric aortas has not been reported. Methods MNPs from aortic aneurysm walls, occlusive plaques, and fresh cadaveric aortas were measured using pyrolysis-gas chromatography/mass spectroscopy including polyethylene (PE), polypropylene (PP), polystyrene, acrylonitrile butadiene styrene (ABS), styrene-butadiene (SBR), poly(methyl methacrylate), polycarbonate, polyvinylchloride (PVC), polyurethane (PU), polyethylene terephthalate, nylon 6, and nylon 66. Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDS) visualized MNPs and characterized milieu for a single aortic plaque for hypothesis generation. Results Nine aneurysms (n=9 male, mean age 71), 6 occlusive plaques (n=4 male, mean age 67), and 12 cadaveric aortas (n=4 male, mean age 35) were collected. In non-atherosclerotic, cadaveric aortas, most prevalent polymers were PE (33.7 μg/g tissue), PVC (33.5 μg/g), and PP (21.3 μg/g). In atherosclerotic cadaveric aortas, most prevalent polymers were PE (99.5 μg/g ), PP (66.7 μg/g ), and PVC (58 μg/g ). For aneurysms, most prevalent polymers were PE (115.8 μg/g), SBR (114.7 μg/g), and PVC (67.3 μg/g). For plaques, most prevalent polymers were PE (745.5 μg/g), PVC (47.5 μg/g ), and SBR (40.3 μg/g). Numerous within group differences between polymers were noted, often following a common theme of which were the most prevalent. Single plaque SEM/EDS demonstrated shard-like MNPs surrounded by calcium/phosphorus, suggesting MNPs reside within plaque calcifications in occlusive disease. Conclusion Aortic atherosclerotic occlusive disease, aortic aneurysms, and both normal and diseased cadaveric aortas all demonstrated detectable levels of MNPs. Nanoplastics were visualized within plaque calcifications in occlusive disease. Further study is needed to elucidate mechanisms regarding how MNPs may play a role in disease development.