Human brain structural change related to acute single exposure to sarin.
OBJECTIVE
This study aimed to identify persistent morphological changes subsequent to an acute single-time exposure to sarin, a highly poisonous organophosphate, and the neurobiological basis of long-lasting somatic and cognitive symptoms in victims exposed to sarin.


METHODS
Thirty-eight victims of the 1995 Tokyo subway sarin attack, all of whom had been treated in an emergency department for sarin intoxication, and 76 matched healthy control subjects underwent T1-weighted and diffusion tensor magnetic resonance imaging (DTI) in 2000 to 2001. Serum cholinesterase (ChE) levels measured immediately and longitudinally after the exposure and the current severity of chronic reports in the victims were also evaluated.


RESULTS
The voxel-based morphometry exhibited smaller than normal regional brain volumes in the insular cortex and neighboring white matter, as well as in the hippocampus in the victims. The reduced regional white matter volume correlated with decreased serum cholinesterase levels and with the severity of chronic somatic complaints related to interoceptive awareness. Voxel-based analysis of diffusion tensor magnetic resonance imaging further demonstrated an extensively lower than normal fractional anisotropy in the victims. All these findings were statistically significant (corrected p < 0.05).


CONCLUSIONS
Sarin intoxication might be associated with structural changes in specific regions of the human brain, including those surrounding the insular cortex, which might be related to elevated subjective awareness of internal bodily status in exposed individuals.
Yamasue
Hidenori
H
Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. yamasue-tky@umin.ac.jp
Abe
Osamu
O
Kasai
Kiyoto
K
Suga
Motomu
M
Iwanami
Akira
A
Yamada
Haruyasu
H
Tochigi
Mamoru
M
Ohtani
Toshiyuki
T
Rogers
Mark A
MA
Sasaki
Tsukasa
T
Aoki
Shigeki
S
Kato
Tadafumi
T
Kato
Nobumasa
N
D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000473:pathology; D001931:Brain Mapping; D002800:Cholinesterase Inhibitors / Q000097:blood / Q000506:poisoning*; D003710:Demography; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012524:Sarin / Q000097:blood / Q000506:poisoning*; D013223:Statistics as Topic
D002800:Cholinesterase Inhibitors; D012524:Sarin