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Contrast Media & Molecular Imaging
Volume 2017, Article ID 6592139, 17 pages
https://doi.org/10.1155/2017/6592139
Review Article

TSPO PET Imaging: From Microglial Activation to Peripheral Sterile Inflammatory Diseases?

1CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France
2Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France

Correspondence should be addressed to Bérenger Largeau; rf.sruot-vinu.ute@uaegral.regnereb

Received 26 May 2017; Revised 1 August 2017; Accepted 7 August 2017; Published 25 September 2017

Academic Editor: Anne Roivainen

Copyright © 2017 Bérenger Largeau et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Peripheral sterile inflammatory diseases (PSIDs) are a heterogeneous group of disorders that gathers several chronic insults involving the cardiovascular, respiratory, gastrointestinal, or musculoskeletal system and wherein inflammation is the cornerstone of the pathophysiology. In PSID, timely characterization and localization of inflammatory foci are crucial for an adequate care for patients. In brain diseases, in vivo positron emission tomography (PET) exploration of inflammation has matured over the last 20 years, through the development of radiopharmaceuticals targeting the translocator protein-18 kDa (TSPO) as molecular biomarkers of activated microglia. Recently, TSPO has been introduced as a possible molecular target for PSIDs PET imaging, making this protein a potential biomarker to address disease heterogeneity, to assist in patient stratification, and to contribute to predicting treatment response. In this review, we summarized the major research advances recently made in the field of TSPO PET imaging in PSIDs. Promising preliminary results have been reported in bowel, cardiovascular, and rheumatic inflammatory diseases, consolidated by preclinical studies. Limitations of TSPO PET imaging in PSIDs, regarding both its large expression in healthy peripheral tissues, unlike in central nervous system, and the production of peripheral radiolabeled metabolites, are also discussed, regarding their possible consequences on TSPO PET signal’s quantification.