1381-6128/14 $58.00+.00 © 2014 Bentham Science Publishers PET Radioligands for In Vivo Visualization of Neuroinflammation

Abstract: Neuroinflammation is a well-orchestrated, dynamic, multicellular process playing a major role in neurodegenerative disorders. The microglia which make up the innate immune system of the central nervous system are key cellular mediators of neuroinflammatory processes. In normal condition they exert a protective function, providing tissue repair by releasing anti-inflammatory cytokines and neu-rotrophic factors. Upon neuronal injury or infection, they become overactivated, thereby releasing neurotoxic substances, amplifying neu-roinflammation leading to neurodegeneration. Positron emission tomography (PET) provides a sensitive non-invasive imaging technique to study and quantify receptor and enzyme expression. A radiolabeled tracer for a protein (over)expressed in neuroinflammation and more specifically for the overactivated microglia would be useful as a diagnostic tool in the follow-up of neuroinflammation progression and to study the efficacy of anti-inflammatory therapy over time. In this manuscript, an overview of potential PET tracer targets upregu-lated during neuroinflammation is provided together with the current radiotracers used to image these targets. In addition, lead structures to develop radiotracers for new targets are suggested