Lateralized Basal Ganglia Vulnerability to Pesticide Exposure in Asymptomatic Agricultural Workers.

Lewis, Mechelle M.; Sterling, Nicholas W.; Guangwei Du; Eun-Young Lee; Grace Shyu; Goldenberg, Michael; Allen, Thomas; Stetter, Christy; Lan Kong; Snipes, Shedra Amy; Jones, Byron C.; Honglei Chen; Mailman, Richard B.; Xuemei Huang

Pesticide exposure is linked to Parkinson's disease, a neurodegenerative disorder marked by dopamine cell loss in the substantia nigra of the basal ganglia (BG) that often presents asymmetrically. We previously reported that pesticideexposed agricultural workers (AW) have nigral diffusion tensor imaging (DTI) changes. The current study sought to confirm this finding, and explore its hemisphere and regional specificity within BG structures using an independent sample population. Pesticide exposure history, standard neurological exam, high-resolution magnetic resonance imaging (T1/T2-weighted and DTI), and [123I]ioflupane SPECT images (to quantify striatal dopamine transporters) were obtained from 20 AW with chronic pesticide exposure and 11 controls. Based on median cumulative days of pesticide exposure, AW were subdivided into high (AWHi, n=10) and low (AWLo, n=10) exposure groups. BG (nigra, putamen, caudate, and globus pallidus [GP]) fractional anisotropy (FA), mean diffusivity (MD), and striatal [123I]ioflupane binding in each hemisphere were quantified, and compared across exposure groups using analysis of variance. Left, but not right, nigral and GP FA were significantly lower in AW compared with controls (p's Hi (p≤.037) but not the AWLo subgroup. AW, especially those with higher pesticide exposure history, demonstrate lateralized microstructural changes in the nigra and GP, whereas striatal areas appear relatively unaffected. Future studies should elucidate how environmental toxicants cause differential lateralized- and regionally specific brain vulnerability.

BASAL ganglia; PESTICIDES; HEALTH of agricultural laborers; PARKINSON'S disease; ENVIRONMENTAL toxicology

Toxicological Sciences, 2017, Vol 159, Issue 1, p170

1096-6080

Academic Journal

10.1093/toxsci/kfx126