A1 Journal article – refereed

Human brown adipose tissue [15O]O2 PET imaging in the presence and absence of cold stimulus




List of Authors: Mueez u Din, Juho Raiko, Teemu Saari, Nobu Kudomi, Tuula Tolvanen, Vesa Oikonen, Jarmo Teuho, Hannu T Sipilä, Nina Savisto, Riitta Parkkola, Pirjo Nuutila, Kirsi A Virtanen

Publisher: Springer

Place: Berlin Heidelberg

Publication year: 2016

Journal: European Journal of Nuclear Medicine and Molecular Imaging

Journal acronym: Eur J Nucl Med Mol Imaging

Volume number: 43

Issue number: 10

Number of pages: 9

ISSN: 1619-7070

eISSN: 1619-7089

DOI: http://dx.doi.org/10.1007/s00259-016-3364-y


Abstract
Purpose

Brown adipose tissue (BAT) is considered a potential target for combatting obesity, as it produces heat instead of ATP in cellular respiration due to uncoupling protein-1 (UCP-1) in mitochondria. However, BAT-specific thermogenic capacity, in comparison to whole-body thermogenesis during cold stimulus, is still controversial. In our present study, we aimed to determine human BAT oxygen consumption with [15O]O2 positron emission tomography (PET) imaging. Further, we explored whether BAT-specific energy expenditure (EE) is associated with BAT blood flow, non-esterified fatty acid (NEFA) uptake, and whole-body EE.

Methods

Seven healthy study subjects were studied at two different scanning sessions, 1) at room temperature (RT) and 2) with acute cold exposure. Radiotracers [15O]O2, [15O]H2O, and [18F]FTHA were given for the measurements of BAT oxygen consumption, blood flow, and NEFA uptake, respectively, with PET-CT. Indirect calorimetry was performed to assess differences in whole-body EE between RT and cold.

Results

BAT-specific EE and oxygen consumption was higher during cold stimulus (approx. 50 %); similarly, whole-body EE was higher during cold stimulus (range 2–47 %). However, there was no association in BAT-specific EE and whole-body EE. BAT-specific EE was found to be a minor contributor in cold induced whole-body thermogenesis (almost 1 % of total whole-body elevation in EE). Certain deep muscles in the cervico-thoracic region made a major contribution to this cold-induced thermogenesis (CIT) without any visual signs or individual perception of shivering. Moreover, BAT-specific EE associated with BAT blood flow and NEFA uptake both at RT and during cold stimulus.

Conclusion

Our study suggests that BAT is a minor and deep muscles are a major contributor to CIT. In BAT, both in RT and during cold, cellular respiration is linked with circulatory NEFA uptake.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-016-3364-y) contains supplementary material, which is available to authorized users.

Keywords: Brown adipose tissue, cold-induced thermogenesis, oxygen consumption, [15O]O2 PET imaging


Last updated on 2021-24-06 at 11:20