Selective D2 receptor PET in manganese-exposed workers
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Updated: Feb 6, 2026

Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of ManganeseII Acetylacetonate
Published on: June 18, 2020
Susan R Criswell1, Mark N Warden1, Susan Searles Nielsen1
1From the Department of Neurology (S.R.C., M.N.W., S.S.N., J.S.P., J.L.-K., B.A.R.), Department of Radiology (J.S.P., S.M.M.), Department of Neuroscience (J.S.P.), Program in Physical Therapy (J.S.P.), Program in Occupational Therapy (J.S.P.), and Department of Biochemistry and Molecular Biophysics (S.M.M.), Washington University School of Medicine, St. Louis, MO; Department of Environmental and Occupational Health Sciences (L.S.) and Department of Biostatistics (L.S.), University of Washington, School of Public Health, Seattle; Department of Family Medicine and Public Health (H.C.) and Department of Neurosciences (H.C.), University of California, San Diego, School of Medicine, La Jolla; and School of Public Health (B.A.R.), Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa.
Objective:
To investigate the associations between manganese (Mn) exposure, D2 dopamine receptors (D2Rs), and parkinsonism using [11C](N-methyl)benperidol (NMB) PET.
Methods:
We used NMB PET to evaluate 50 workers with a range of Mn exposure: 22 Mn-exposed welders, 15 Mn-exposed workers, and 13 nonexposed workers. Cumulative Mn exposure was estimated from work histories, and movement disorder specialists examined all workers. We calculated NMB D2R nondisplaceable binding potential (BPND) for the striatum, globus pallidus, thalamus, and substantia nigra (SN). Multivariate analysis of covariance with post hoc descriptive discriminate analysis identified regional differences by exposure group. We used linear regression to examine the association among Mn exposure, Unified Parkinson's Disease Rating Scale motor subsection 3 (UPDRS3) score, and regional D2R BPND.
Results:
D2R BPND in the SN had the greatest discriminant power among exposure groups (p < 0.01). Age-adjusted SN D2R BPND was 0.073 (95% confidence interval [CI] 0.022-0.124) greater in Mn-exposed welders and 0.068 (95% CI 0.013-0.124) greater in Mn-exposed workers compared to nonexposed workers. After adjustment for age, SN D2R BPND was 0.0021 (95% CI 0.0005-0.0042) higher for each year of Mn exposure. Each 0.10 increase in SN D2R BPND was associated with a 2.65 (95% CI 0.56-4.75) increase in UPDRS3 score.
Conclusions And Relevance:
Nigral D2R BPND increased with Mn exposure and clinical parkinsonism, indicating dose-dependent dopaminergic dysfunction of the SN in Mn neurotoxicity.
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