June 8, 2015
Neuroinflammation caused by a reactive immune system could be tripping off the neurodegeneration seen in certain dementias, multiple sclerosis, and other deadly diseases of the nervous system. A novel molecular imaging technique could be the key to understanding how best to treat these and other devastating diseases, according to a recent study presented at the 2015 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI).
At the heart of this maladaptive immune response are microglia, immune cells in the central nervous system that can be activated to trigger neuroinflammation. For this study, researchers used positron emission tomography (PET) to measure activation of microglia by employing a molecule from E. coli bacteria called lipopolysaccharide (LPS), or endotoxin. LPS stimulates the immune system and is accompanied by a radiotracer called carbon-11 PBR28 (C-11 PBR28). This form of molecular imaging allows the minimally invasive visualization of neuroinflammation. C-11 PBR28, is injected and binds to translocator proteins expressed on activated microglia. A PET scanner can then detect the radioactive particles emitted from inside the brain, representing areas of increased microglial activation before and after immune stimulation with LPS.