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Published on: January 7, 2014
Extrastriatal spreading of microglial activation in Parkinson's disease: a positron emission tomography study
Tatsuhiro Terada1, Masamichi Yokokura2, Etsuji Yoshikawa3
1Department of Biofunctional Imaging, Medical Photonics Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192, Japan.
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.
Conclusion:
The current results indicated that an extrastriatal spreading of microglial activation reflects one of PD pathophysiology occurring at an early stage.
Insights
Early Parkinson's disease (PD) shows spreading microglial activation, particularly in the extrastriate cortex. This neuroinflammation increases over one year, highlighting its role in early PD progression.
Area of Science:
- Neuroscience
- Radiochemistry
- Neurology
Background:
- Neuroinflammation, driven by glial cells, is implicated in Parkinson's disease (PD) pathogenesis.
- The precise pattern and progression of microglial activation in early PD remain incompletely understood.
Purpose of the Study:
- To investigate the pattern and progression of microglial activation in early-stage Parkinson's disease.
- To quantify neuroinflammation using a specific positron emission tomography (PET) tracer.
Main Methods:
- Utilized PET imaging with [(11)C]DPA713, a tracer for microglial activation, in 11 early PD patients (Hoehn and Yahr stages 1-2).
- Scans were conducted twice, one year apart, to assess changes in binding potential (BPND) using the simplified reference tissue model.
- Employed voxelwise and region of interest analyses for comprehensive assessment of regional BPND.
Main Results:
- [(11)C]DPA713 BPND significantly increased in extrastriatal regions, including the occipital, temporal, and parietal cortex, in PD patients.
- A marked increase in BPND was observed over one year, predominantly in the temporal and occipital cortex.
- These findings suggest a progressive extrastriatal spread of microglial activation.
Conclusions:
- Extrastriate microglial activation spreading is a key pathological feature of early-stage Parkinson's disease.
- This study provides in vivo evidence of neuroinflammation progression in early PD.
