Specificity of translocator protein-targeted positron emission tomography in inflammatory joint disease

Helo, Yusuf; Searle, Graham E.; Borghese, Federica; Abraham, Sonya; Saleem, Azeem

doi:10.1186/s13550-020-00736-9

Specificity of translocator protein-targeted positron emission tomography in inflammatory joint disease

Helo, Yusuf; Searle, Graham E.; Borghese, Federica; Abraham, Sonya; Saleem, Azeem

Authors

Yusuf Helo

Graham E. Searle

Federica Borghese

Sonya Abraham

Dr Azeem Saleem A.Saleem@hull.ac.uk
Reader and Honorary Consultant in Clinical Oncology

Abstract

© 2020, The Author(s). Objective: Expression of the translocator protein (TSPO) on inflammatory cells has facilitated imaging of synovitis with TSPO-targeted positron emission tomography (PET). We aimed to quantitatively assess the specificity of the second-generation TSPO PET radioligand, [11C]PBR28, and to generate simplified PET protocols in patients with inflammatory joint disease (IJD) in this pilot study. Methods: Three IJD patients (two rheumatoid arthritis and one osteoarthritis) with knee involvement underwent dynamic [11C]PBR28-PET scans before and after administration of 90 mg of oral emapunil (XBD-173), a TSPO ligand the same day. Radial arterial blood sampling was performed throughout the scan, and total radioactivity and radioactive metabolites were obtained. A semi-automated method was used to generate regions of interest. Standardized uptake value (SUV) and SUV ratio corrected for activity in bone and blood between 50 and 70 min (SUVr50–70 bone, SUVr50–70 blood, respectively) and PET volume of distribution (VT) of the radioligand were calculated. Results: A mean [11C]PBR28 radioactivity of 378 (range 362–389) MBq was administered. A significant decrease (p < 0.05) in VT, SUVr50–70 bone and SUVr50–70 blood observed after oral emapunil confirmed the TSPO specificity of [11C]PBR28. A decrease in SUV was not observed in the post-block scan. Conclusion: [11C]PBR28 is TSPO-specific radioligand in IJD patients. Simplified PET protocols with static PET acquisition can be used in the management and evaluation of novel therapeutics that target TSPO overexpressing cells.

Citation

Helo, Y., Searle, G. E., Borghese, F., Abraham, S., & Saleem, A. (2020). Specificity of translocator protein-targeted positron emission tomography in inflammatory joint disease. EJNMMI Research, 10(1), Article 147. https://doi.org/10.1186/s13550-020-00736-9

Journal Article Type	Article
Acceptance Date	Nov 23, 2020
Online Publication Date	Dec 7, 2020
Publication Date	Dec 7, 2020
Deposit Date	Jan 20, 2021
Publicly Available Date	Jan 20, 2021
Journal	EJNMMI Research
Print ISSN	2191-219X
Electronic ISSN	2191-219X
Publisher	Springer Verlag
Peer Reviewed	Peer Reviewed
Volume	10
Issue	1
Article Number	147
DOI	https://doi.org/10.1186/s13550-020-00736-9
Keywords	Radiology Nuclear Medicine and imaging
Public URL	https://hull-repository.worktribe.com/output/3674238
Publisher URL	https://ejnmmires.springeropen.com/articles/10.1186/s13550-020-00736-9

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