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Brain: see neuroinflammation


​How to observe the mechanisms of neuroinflammation during the development of neurodegenerative diseases? A team from the CEA's FrédéricJoliot Institute is testing tracers for PET imaging.

Published on 3 April 2017

​Abstract

Cannabinoid type 2 receptors (CB2R) have emerged as promising targets for the diagnosis and therapy of brain pathologies. However, no suitable radiotracers for accurate CB2R mapping have been found to date, limiting the investigation of the CB2 receptor expression using positron emission tomography (PET) imaging. In this work, we report the evaluation of the in vivo expression of CB2R with [11C]A-836339 PET after cerebral ischemia and in two rat models of neuroinflammation, first by intrastriatal LPS and then by AMPA injection. PET images and in vitro autoradiography showed a lack of specific [11C]A-836339 uptake in these animal models demonstrating the limitation of this radiotracer to image CB2 receptor under neuroinflammatory conditions. Further, using immunohistochemistry, the CB2 receptor displayed a modest expression increase after cerebral ischemia, LPS and AMPA models. Finally, [18F]DPA-714-PET and immunohistochemistry demonstrated decreased neuroinflammation by a selective CB2R agonist, JWH133. Taken together, these findings suggest that [11C]A-836339 is not a suitable radiotracer to monitor in vivo CB2R expression by using PET imaging. Future studies will have to investigate alternative radiotracers that could provide an accurate binding to CB2 receptors following brain inflammation.

Read the French version.

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