Bioaccumulation of microplastics in decedent human brains.
Level 4 - case-series / case-control
Postmortem cross-sectional tissue analysis and case-control comparison
PubMed 39901044 · doi:10.1038/s41591-024-03453-1
What was done
Analyzed micro- and nanoplastics (MNPs) in postmortem human kidney, liver, and brain tissues using pyrolysis gas chromatography-mass spectrometry, attenuated total reflectance-Fourier transform infrared spectroscopy, and electron microscopy with energy-dispersive spectroscopy. Evaluated associations between tissue concentrations and demographic variables, year of death (2016 versus 2024), and dementia status.
What was found
Polyethylene was the primary MNP detected across tissues, with the brain harboring higher relative proportions of polyethylene presenting largely as nanoscale shard-like fragments under electron microscopy. Plastic concentrations were not associated with age, sex, race/ethnicity, or cause of death, but concentrations increased significantly in both liver and brain samples from 2016 to 2024 (P = 0.01). Decedent brains with a documented dementia diagnosis showed greater MNP accumulation, particularly within cerebrovascular walls and immune cells. Specific baseline and follow-up plastic concentration values were not reported in the abstract.
Why it matters
Demonstrates that environmental micro- and nanoplastics can cross into human brain tissue, show increasing postmortem accumulation over time, and correlate with dementia pathology.
Limits
The abstract reports no total sample size (n), quantitative concentration values, or effect estimates. Because this is an observational postmortem study, it cannot establish whether MNP accumulation contributes causally to dementia or reflects secondary accumulation resulting from disease-associated blood-brain barrier dysfunction.
Cited by
- partial Micro- and nanoplastics make up as much as 0.5% of the brain's weight (about a teaspoon).