Microplastics in decedents with and without dementia
Data files
Dec 13, 2024 version files 34.70 KB
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All_Organs_total_spreadsheet_NatMed_for_Dryad.csv
24.60 KB
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Dementia_only_for_Dryad.csv
2.09 KB
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East_Coast_Samples.csv
4.42 KB
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README.md
3.60 KB
Abstract
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.
README: Microplastics in decedents with and without dementia
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
Methods
Human Tissue Samples: The same tissue collection protocol at the UNM OMI was used for 2016 and 2024. Small pieces of representative organs (3 to 5 cm3) 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.
Py-GC/MS Detection of Polymer Solids: 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-CaCO3 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).