Imaging of glial cells by positron-emitted peripheral benzodiazepine receptor ligands

Recently, it has been indicated that glial cells play as important role in the development of neurodegenerative disorders. Expression of peripheral benzodiazepine receptor (PBR) has higher localization in the glial cells than in the neural cells, and is a noticeable marker for gliosis produced by neurodegeneration. In vivo imaging of PBR has been attempted by [ ¹¹C]PK11195 positron emission tomography (PET), and it has been documented that the [¹¹C]PK11195 binding potential increases in various neurodegenerative disorders such as Alzheimer's disease and stroke. Furthermore, we have succeeded in developing new positron ligands [ ¹¹C]DAA1106 and [¹⁸F]fluoroethyl-DAA1106 for visualization of PBRs, which have higher accumulation in the brain than [¹¹C] PK11195. We concluded that PET imaging by PBR ligands is useful for diagnosis of neurodegenerative disorders.