Increased R2* in the Caudate Nucleus of Asymptomatic Welders
Eun-Young Lee*,1, Michael R. Flynn†, Guangwei Du*, Yunqing Li*, Mechelle M. Lewis*,‡, Amy H. Herring§, Eric Van Buren§, Scott Van Buren§, Lan Kong¶, Rebecca C. Fry†, Amanda M. Snyder||, James R. Connor||, Qing X. Yang|||, Richard B. Mailman*,‡
and Xuemei Huang*,‡|||||||||,2
Toxicol. Sci. (2016) 150 (2): 369-377.
doi: 10.1093/toxsci/kfw003
First published online: January 14, 2016
*Department of Neurology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania;
†Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina;
‡Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania;
§Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina;
¶Department of Public Health Sciences, Pennsylvania State University, Hershey, Pennsylvania;
||Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania;
|||Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and
||||Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
↵2To whom correspondence should be addressed at Department of Neurology, Penn State University-Milton S. Hershey Medical Center, H037, 500 University Drive, Hershey, PA 17033-0850. Fax: (717) 531-0266. E-mail:
Xuemei@psu.edu.
Abstract
Welding has been associated with neurobehavioral disorders. Welding fumes contain several metals including copper (Cu), manganese (Mn), and iron (Fe) that may interact to influence welding-related neurotoxicity. Although welding-related airborne Fe
levels are about 10-fold higher than Mn, previous studies have focused on Mn and its accumulation in the basal ganglia. This study examined differences in the apparent transverse relaxation rates [R2* (1/T2*), estimate of Fe accumulation] in the basal
ganglia (caudate nucleus, putamen, and globus pallidus) between welders and controls, and the dose–response relationship between estimated Fe exposure and R2* values. Occupational questionnaires estimated recent and lifetime Fe exposure, and blood Fe
levels and brain magnetic resonance imaging (MRI) were obtained. Complete exposure and MRI R2* and R1 (1/T1: measure to estimate Mn accumulation) data from 42 subjects with welding exposure and 29 controls were analyzed. Welders had significantly greater
exposure metrics and higher whole-blood Fe levels compared with controls. R2* in the caudate nucleus was significantly higher in welders after controlling for age, body mass index, respirator use, caudate R1, and blood metals of Cu and Mn, whereas there
was no difference in R1 values in the basal ganglia between groups. The R2* in the caudate nucleus was positively correlated with whole-blood Fe concentration. This study provides the first evidence of higher R2* in the caudate nucleus of welders, which
is suggestive of increased Fe accumulation in this area. Further studies are needed to replicate the findings and determine the neurobehavioral relevance.
Key words
welders iron R2* basal ganglia caudate nucleus
© The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail:
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