Although V<sub>T</sub> for [<sup>18</sup>F]GE-180 is low, indicating low brain penetration, half the signal shown by MS subjects reflected specific TSPO binding.
These findings support the notion that TSPO is a valuable marker for the in vivo visualization and quantification of neuropathological changes in the MS brain.
The TSPO radioligand [<sup>18</sup>F]DPA714 can reliably identify increased focal and diffuse neuroinflammation in progressive MS when using plasma input-derived binding potential, but observed differences were predominantly visible in high-affinity binders.
18-kDa translocator protein (TSPO)-binding radioligands have been used to detect activated microglial cells at different stages of MS, and remyelination has been measured using amyloid PET.
The aim of this study was to evaluate neuroinflammation in a mouse MS model (EAE) using TSPO-PET with <sup>18</sup>F-VC701, in combination with magnetic resonance imaging (MRI).
However, existing literature regarding TSPO expression on human activated macrophages is lacking, mostly deriving from brain tissue studies, including studies of brain malignancy, and inflammatory diseases such as multiple sclerosis.
Four clinically and radiologically stable relapsing-remitting MS subjects (age 41 ± 7 years, two men/two women) and four HCs (age 42 ± 8 years, 2 two men/two women), matched for translocator protein genotype [two high- and two medium-affinity binders according to DNA polymorphism (rs6971) in each group], were studied for TRV.
We suggest that TSPO protein expression is a potential peripheral biomarker of MS, more research is needed to determine if peripheral TSPO expression may also be altered in other neuroinflammatory conditions.