Summary
Growing levels of microplastics and nanoplastics (MNPs) in the environment have raised questions about how deeply these particles infiltrate the human body, and this study provides striking evidence that they accumulate in major organs, including the kidney, liver, and brain. Using multiple complementary detection methods—pyrolysis GC/MS, ATR-FTIR spectroscopy, and electron microscopy—the researchers confirmed the presence of a variety of polymers, with polyethylene dominating across tissues. Brain samples contained an especially high proportion of polyethylene, and electron microscopy revealed sharp, nanoscale plastic fragments embedded within neural tissue. Importantly, MNP concentrations did not vary by age, sex, race, ethnicity, or cause of death; however, tissue collected in 2024 contained significantly more plastics than tissue collected in 2016, suggesting rapid accumulation over time. The most concerning finding was the even higher plastic burden in brains from individuals with dementia, where MNPs appeared concentrated in blood vessel walls and immune cells. These results underscore the need to understand how plastics enter and move through the body, how they accumulate in the brain, and what health consequences they may pose—especially in relation to neurodegenerative disease.
PMID: 39901044
PMCID: PMC12003191
DOI: 10.1038/s41591-025-03675-x
Abstract
Rising global concentrations of environmental microplastics and nanoplastics (MNPs) drive concerns for human exposure and health outcomes. Complementary methods for the robust detection of tissue MNPs, including pyrolysis gas chromatography–mass spectrometry, attenuated total reflectance–Fourier transform infrared spectroscopy and electron microscopy with energy-dispersive spectroscopy, confirm the presence of MNPs in human kidney, liver and brain. MNPs in these organs primarily consist of polyethylene, with lesser but significant concentrations of other polymers. Brain tissues harbor higher proportions of polyethylene compared to the composition of the plastics in liver or kidney, and electron microscopy verified the nature of the isolated brain MNPs, which present largely as nanoscale shard-like fragments. Plastic concentrations in these decedent tissues were not influenced by age, sex, race/ethnicity or cause of death; the time of death (2016 versus 2024) was a significant factor, with increasing MNP concentrations over time in both liver and brain samples (P = 0.01). Finally, even greater accumulation of MNPs was observed in a cohort of decedent brains with documented dementia diagnosis, with notable deposition in cerebrovascular walls and immune cells. These results highlight a critical need to better understand the routes of exposure, uptake and clearance pathways and potential health consequences of plastics in human tissues, particularly in the brain.
Nihart AJ, Garcia MA, El Hayek E, Liu R, Olewine M, Kingston JD, Castillo EF, Gullapalli RR, Howard T, Bleske B, Scott J, Gonzalez-Estrella J, Gross JM, Spilde M, Adolphi NL, Gallego DF, Jarrell HS, Dvorscak G, Zuluaga-Ruiz ME, West AB, Campen MJ. Bioaccumulation of microplastics in decedent human brains. Nat Med. 2025 Apr;31(4):1114-1119. doi: 10.1038/s41591-024-03453-1. Epub 2025 Feb 3. Erratum in: Nat Med. 2025 Apr;31(4):1367. doi: 10.1038/s41591-025-03675-x. PMID: 39901044; PMCID: PMC12003191.