Extrastriatal spreading of microglial activation in Parkinson's disease: a positron emission tomography study.
BACKGROUND
The neuroinflammatory glial response contributes to the degenerative process in Parkinson's disease (PD). However, the pattern of microglial progression remains unclear.


METHODS
We evaluated microglial activation in early stage PD patients by quantifying changes in neuroinflammation using PET with [(11)C]DPA713, a selective PET tracer for microglial activation. Eleven PD patients (Hoehn and Yahr stages 1-2) without dementia underwent the [(11)C]DPA713 PET scan two times with 1 year apart. The binding potential (BPND) was estimated with the simplified reference tissue model. Voxelwise and regions of interest analyses were used to compare the regional BPND among groups.


RESULTS
Significant increase in [(11)C]DPA713 BPND was found extrastriatally in the occipital, temporal and parietal cortex in PD patients, and the degree of BPND became much higher over the brain regions predominantly in the temporal and occipital cortex 1 year later.


CONCLUSIONS
The current results indicated that an extrastriatal spreading of microglial activation reflects one of PD pathophysiology occurring at an early stage.
Department of Biofunctional Imaging, Medical Photonics Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192, Japan.
Tatsuhiro
T
Terada
Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Masamichi
M
Yokokura
Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Japan.
Etsuji
E
Yoshikawa
Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Japan.
Masami
M
Futatsubashi
First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Satoshi
S
Kono
First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Takashi
T
Konishi
First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Hiroaki
H
Miyajima
Osaka Ohtani University, Tondabayashi, Japan.
Takanori
T
Hashizume
Department of Biofunctional Imaging, Medical Photonics Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192, Japan. ouchi@hama-med.ac.jp.
Yasuomi
Y
Ouchi
D000081:Acetamides / Q000378:metabolism; D000368:Aged; D002250:Carbon Radioisotopes; D005260:Female; D006801:Humans; D008297:Male; D017628:Microglia / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D049268:Positron-Emission Tomography; D011720:Pyrazoles / Q000378:metabolism; D011743:Pyrimidines / Q000378:metabolism
D000081:Acetamides; D002250:Carbon Radioisotopes; C507091:N,N-diethyl-2-(2-(4-methoxyphenyl)-5,7-dimethyl-pyrazolo(1,5-a)pyrimidin-3-yl)-acetamide; D011720:Pyrazoles; D011743:Pyrimidines
Microglia; Parkinson’s disease (PD); Positron emission tomography (PET); [11C]DPA713