PET Imaging of Human Brown Adipose Tissue with the TSPO Tracer [11C]PBR28
Brown adipose tissue (BAT) in adult humans has been recently rediscovered and intensively investigated as a new potential therapeutic target for obesity and type 2 diabetes (T2D). However, reliable assessment of BAT mass in vivo represents a considerable challenge. The purpose of this investigation is to demonstrate for the first time that human BAT depots can be imaged with a translocator protein (TSPO)-specific positron emission tomography (PET) tracer [11C]PBR28 under thermoneutral conditions.
In this retrospective analysis, we analyzed the images of three healthy volunteers who underwent PET/magnetic resonance (MR) imaging after injection of 14 m Ci of [11C]PBR28 at room temperature. Thirty-minute static PET images were reconstructed from the data obtained 60–90 min after the injection of the tracer.
[11C]PBR28 uptake in the neck/supraclavicular regions was identified, which was parallel to the known distribution pattern of human BAT depots. These areas co-localized with the areas of hyperintensity and corresponded to fat on T1-weighted MR images. Standardized uptake value (SUV) was used to quantify [11C]PBR28 signal in BAT depots. The average (± SD) SUV(mean) and SUVmax for BAT depots was 2.13 (± 0.33) and 3.19 (± 0.34), respectively, while the average SUV(mean) for muscle and subcutaneous adipose tissue was 0.79 (± 0.1) and 0.18 (± 0.04), respectively.
In this brief article, we provide the first evidence suggesting that [11C]PBR28, a widely available TSPO-specific PET tracer, can be used for imaging human BAT mass under thermoneutral conditions.
Key wordsBrown adipose tissue TSPO C-11 PBR28 Metabolic disease Thermoneutral conditions
We thank China Scholarship Council of Chinese Ministry of Education for support (J.Y. and J.Y.). We also thank Alana W. Ross, B.S. for proofreading this manuscript.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- 13.Gnad T, Scheibler S, von Kugelgen I et al (2014) Adenosine activates brown adipose tissue and recruits beige adipocytes via A receptors. Nature 546:544–548Google Scholar
- 40.Yang J, Yang J, Moore A, Liang S, Ran C (2017) Synthesis-free PET imaging of brown adipose tissue and TSPO via combination of disulfiram and 64CuCl2. Sci Rep 7(1):8298Google Scholar
- 45.Dupont AC, Largeau B, Santiago Ribeiro MJ et al (2017) Translocator protein-18 kDa (TSPO) positron emission tomography (PET) imaging and its clinical impact in neurodegenerative diseases. Int J Mol Sci. https://doi.org/10.3390/ijms18040785
- 58.Veronese M, Reis Marques T, Bloomfield PS, et al. (2017) Kinetic modelling of [11C]PBR28 for 18 kDa translocator protein PET data: a validation study of vascular modelling in the brain using XBD173 and tissue analysis. J Cereb Blood Flow Metabol. https://doi.org/10.1177/0271678X17712388