DOI: 10.5061/dryad.b8gtht7p8
title: Microplastics in decedents with and without dementia

description: Rising global concentrations of environmental micro- 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 spectrometry, 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 plastic composition in the 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, an even greater accumulation of MNPs
 was observed in a cohort of decedent's brains with a documented
 dementia diagnosis, with notable deposition in cerebrovascular walls and
 in 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.
description: <em>Human Tissue Samples:</em> The same tissue
 collection protocol at the UNM OMI was used for 2016 and 2024. Small
 pieces of representative organs (3 to 5 cm<sup>3</sup>) were
 routinely collected at autopsy and stored in 10% formalin. Additionally,
 decedent samples from a cohort with confirmed dementia (N=12) were
 included and collected at the UNM OMI under identical procedures. Limited
 demographic data (age, sex, race/ethnicity, cause of death, date of death)
 were available due to the conditions of specimen approval; age of death,
 race/ethnicity, and sex were relatively consistent across cohorts (Table
 S1).  Additional brain samples (N=28) were obtained from repositories on
 the East Coast of the United States to provide a greater range for the
 year of death (going back to 1997). All studies were approved by the
 respective Institutional Review Boards.
 <em>Py-GC/MS Detection of Polymer
 Solids:</em> Briefly, solid particulates are isolated from
 chemically digested tissue samples, then combusted to reveal signature
 mass spectra for select polymers (full details in the Supplemental
 Information, Section 1.2).  Thus, the Py-GC/MS output is derived from
 enriched solid polymer particles and not soluble components from the
 digested tissue. Samples (approximately 500 mg) were digested with 10%
 potassium hydroxide for at least 3d at 40°C. Samples were then
 ultracentrifuged at 100,000 x g for 4h to generate a pellet enriched in
 solid materials resistant to such digestion, which included polymer-based
 solids. A 1–2 mg portion of the resulting pellet was then analyzed by
 single-shot Py-GC/MS and compared to a
 microplastics-CaCO<sub>3</sub> standard containing 12 specific
 polymers: polyethylene (PE), polyvinyl chloride (PVC), nylon 66 (N66),
 styrene-butadiene (SBR), acrylonitrile butadiene styrene (ABS),
 polyethylene terephthalate (PET), nylon 6 (N6), poly(methyl methacrylate)
 (PMMA), polyurethane (PU), polycarbonate (PC), polypropylene (PP), and
 polystyrene (PS). Py-GCMS operating settings and polymer pyrolyzate
 targets are described in Tables S2 and S3, with examples of spectra from
 samples, standards, and blanks shown in Figures S2-S4. Polymer spectra
 were identified via the F-Search MPs v2.1 software (Frontier Labs). The
 resulting data were normalized to the original sample weight to render a
 mass concentration (µg/g).
description: # Microplastics in decedents with and without dementia
 [https://doi.org/10.5061/dryad.b8gtht7p8](https://doi.org/10.5061/dryad.b8gtht7p8) ## Description of the data and file structure Demographic and analytical results of samples for plastics using pyrolysis gas chromatography-mass spectrometry (PyGCMS). "Null" is used to denote cells where log-transformed values of zero would cause an error. "Unknown" refers to data lost in the record. ### Files and variables #### File: All\_Organs\_total\_spreadsheet\_NatMed.csv ##### Variables * Organ (Brain, Liver, Kidney) * Tube Letter: Sample identifier * DOD: Date of death (year) * Age: Age (years) * COD: Cause of death (1=accident/trauma; 2= substance use related; 3=natural disease or undetermined) * Total: Sum of all polymers in micrograms/gram of tissue weight * PE: Polyethylene in micrograms/gram of tissue weight * PP: Polypropylene in micrograms/gram of tissue weight * PS: Polystyrene in micrograms/gram of tissue weight * ABS: Acrylonitrile-butadiene-styrene in micrograms/gram of tissue weight * SBR: Styrene-butadiene rubber in micrograms/gram of tissue weight * PMMA: Polymethyl methacrylate in micrograms/gram of tissue weight * PC: Polycarbonate in micrograms/gram of tissue weight * PVC: Polyvinyl chloride in micrograms/gram of tissue weight * PU: Polyurethane in micrograms/gram of tissue weight * PET: Polyethylene terephthalate in micrograms/gram of tissue weight * N6: Nylon 6 in micrograms/gram of tissue weight * N66: Nylon 6,6 in micrograms/gram of tissue weight * LogTotal: Log transformed total plastics * LogPE: Log-transformed polyethylene #### File: Dementia\_only.csv ##### Variables * Case#: Unique identifier * Tube Letter: Secondary identifier * Subdiagnosis: Dementia subtype * Age: Age at Death * Brain total: Sum of all polymers in micrograms/gram of tissue weight * PE: Polyethylene in micrograms/gram of tissue weight * PP: Polypropylene in micrograms/gram of tissue weight * PS: Polystyrene in micrograms/gram of tissue weight * ABS: Acrylonitrile-butadiene-styrene in micrograms/gram of tissue weight * SBR: Styrene-butadiene rubber in micrograms/gram of tissue weight * PMMA: Polymethyl methacrylate in micrograms/gram of tissue weight * PC: Polycarbonate in micrograms/gram of tissue weight * PVC: Polyvinyl chloride in micrograms/gram of tissue weight * PU: Polyurethane in micrograms/gram of tissue weight * PET: Polyethylene terephthalate in micrograms/gram of tissue weight * N6: Nylon 6 in micrograms/gram of tissue weight * N66: Nylon 6,6 in micrograms/gram of tissue weight #### File: East\_Coast\_Samples.csv ##### Variables * Brain Bank ID: Unique identifier * Age: Age * Date of Death: Date of Death * Collection Site: State of the collection * Total: Sum of all polymers in micrograms/gram of tissue weight * PE: Polyethylene in micrograms/gram of tissue weight * PP: Polypropylene in micrograms/gram of tissue weight * PS: Polystyrene in micrograms/gram of tissue weight * ABS: Acrylonitrile-butadiene-styrene in micrograms/gram of tissue weight * SBR: Styrene-butadiene rubber in micrograms/gram of tissue weight * PMMA: Polymethyl methacrylate in micrograms/gram of tissue weight * PC: Polycarbonate in micrograms/gram of tissue weight * PVC: Polyvinyl chloride in micrograms/gram of tissue weight * PU: Polyurethane in micrograms/gram of tissue weight * PET: Polyethylene terephthalate in micrograms/gram of tissue weight * N6:Nylon 6 in micrograms/gram of tissue weight * N66: Nylon 6,6 in micrograms/gram of tissue weight ## Access information NA