Cellular sources of TSPO expression in healthy and diseased brain.
Level 5 - mechanism / opinion, no new human data
Narrative review of preclinical and human studies without systematic search methodology
PubMed 33433698 · doi:10.1007/s00259-020-05166-2
What was done
This narrative review summarizes human studies and animal disease models investigating the cellular sources, functions, and quantification methods of the 18 kDa translocator protein (TSPO) in healthy and diseased central nervous systems, evaluating its role as a positron emission tomography (PET) marker of neuroinflammation.
What was found
The abstract reports no numerical data. It notes that there is little evidence supporting microglia-specific TSPO expression in PET imaging. Instead, alterations in TSPO binding, the cellular sources involved, and their functional significance depend on the specific disease or animal model, disease stage, and brain regions evaluated.
Why it matters
Assuming TSPO PET signals reflect only microglial activation oversimplifies neuroinflammatory imaging and may mislead mechanistic conclusions. Defining the precise cellular contributors across different brain conditions is essential for interpreting neuroimaging and identifying disease-specific therapeutic pathways.
Limits
The abstract contains no quantitative metrics or systematic review criteria. The findings depend on heterogeneous animal models that may not accurately reflect human neuropathology, and the precise cellular dynamics governing TSPO expression remain incompletely resolved.
Cited by
- context TSPO PET imaging can detect activated microglia in living humans.