Nigral MRI features of asymptomatic welders. (April 2021)

• Record Type: Journal Article
• Authors: Lee, Eun-Young; Flynn, Michael R.; Du, Guangwei; Lewis, Mechelle M.; Goldenberg, Michael; Kong, Lan; Mailman, Richard B.; Hong, Young-Seoub; Huang, Xuemei
• Is Part Of: Parkinsonism & related disorders. Volume 85(2021)
• Page Start: 37
• Page End: 43
• Publication Date: 2021-04
• Subjects: Welding -- Manganese exposure -- Diffusion fractional anisotropy -- R2* -- Parkinson's disease/parkinsonism; Parkinson's disease -- Periodicals; Movement disorders -- Periodicals; Movement Disorders -- Periodicals; Nerve Degeneration -- Periodicals; Nervous System Diseases -- Periodicals; Parkinson Disease -- Periodicals; Tremor -- Periodicals; Parkinson, Maladie de -- Périodiques; Parkinson's disease; 616.833
• DOI: 10.1016/j.parkreldis.2021.02.020
• Languages: English
• ISSNs: 1353-8020

Abstract

Abstract: Introduction: Manganese (Mn)-induced parkinsonism involves motor symptoms similar to those observed in Parkinson's disease (PD). Previous literature suggests that chronic Mn- exposure may increase PD risk, although Mn-induced clinical syndromes are considered atypical for PD. This study investigated whether asymptomatic welders display differences in the substantia nigra (SN), the key pathological locus of PD. Method: Brain MRI data and occupational exposure history were obtained in welders (N = 43) and matched controls (N = 31). Diffusion tensor imaging fractional anisotropy (FA; estimate of microstructural integrity) and R2* (estimate of iron and other PD-related brain differences) values in the SN pars compacta (SNc), SN reticulata (SNr), and globus pallidus (GP) were compared between the two groups. The MRI markers of the SN and GP within welders were related to exposure estimates. Results: Compared to controls, welders who had chronic, but low-level, Mn-exposure had similar FA and R2* values in both SN regions (p's > 0.082), but significantly lower FA (p = 0.0013), although not R2* (p = 0.553), in the GP. In welders, FA values in the SN and GP showed a second-order polynomial relationship with cumulative lifetime welding exposure (p's < 0.03). Conclusion: Neurotoxic processes associated with Mn-exposure may be different from those in PD when the exposure-level is relatively low. Greater welding duration and level, however, were associated with FA differences in the GP and SN, indicating that welding exposures above a certain level may induce neurotoxicity in the SN, a finding that should be explored further in future studies. Highlights: Low-level welding exposure does not change DTI or R2* in the substantia nigra, but causes lower FA in the globus pallidus. Greater welding duration and level were associated with lower FA values in the GP and SN regions. Mn neurotoxicity affects different brain regions than those in Parkinson's disease, especially with low exposures.