Supraclavicular Skin Temperature as a Measure of 18F-FDG Uptake by BAT in Human Subjects

Abstract

BackgroundBrown adipose tissue (BAT) has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current ‘gold standard’ for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans.Subjects/MethodsBAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years), using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations.ResultsProximal and distal (hand/feet) skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001). Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010) and clavicular BAT volume (R2 = 0.20, P = 0.030) and clavicular SUVmax (R2 = 0.27, P = 0.010), while core body temperature did not.ConclusionsSupraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects.Trial Registration NTR 2473

Daytime variation in ambient temperature affects skin temperatures and blood pressure: Ambulatory winter/summer comparison in healthy young women

“…Furthermore, a recent study has shown, that increased supraclavicular ST reflects increased brown adipose tissue (BAT) activity occurring during cold exposure [37,38]. In our study we measured ST not directly in the supra-, but in the infraclavicular skin region, in which BAT activity is also affected by cold exposure [37,39].…”

Glucagon increases energy expenditure independently of brown adipose tissue activation in humans

“…In rodent studies, thermographic measurement of BAT activity has been validated against biochemical markers of BAT thermogenesis, such as UCP-1 upregulation [34]. In human studies, Jang et al [17] reported that a temperature difference between the neck and sternum of 0.9 ∘ C had a positive predictive value of 85% for the presence of supraclavicular BAT, Symonds et al [18] recorded rises of 0.5 ∘ C in supraclavicular temperature in children after mild cold exposure, and Boon et al [27] reported a 0.4 ∘ C cold-induced supraclavicular skin temperature rise, which positively correlated with 18 F-FDG-PET/CT quantification of underlying BAT. In the present study all eight subjects who had BAT activation after cold exposure as determined by 18 F-FDG-PET/CT also showed a rise in neck temperature, as determined by thermal imaging during cold exposure, although the correlation between PET-quantified BAT mass and cold-induced neck temperature rise was not significant in the present cohort (data not shown).…”

“…All 11 subjects (eight BAT-positive and three BAT-negative, as defined by their 18 F-FDG PET/CT characteristics on cold exposure, described above) also underwent thermography of their neck during the three study visits when calorimetry was performed (Figures 1 and S1A, B). A rise in supraclavicular skin surface temperature has previously been shown to indicate underlying BAT thermogenic activity [17,27]. In the BAT-positive group of eight, there was a significant temperature rise in the neck with cold exposure, with a mean increase in temperature between Run A (baseline) and Run C (end exposure) of 0.44 ± 0.08 ∘ C. In contrast, there was no change in supraclavicular neck temperature with cold exposure in the BAT-negative group ( Figure 5A).…”

The role of BAT in cardiometabolic disorders and aging

“…Although, 18 FDG uptake in a fat depot upon cold exposure is still considered the 'gold standard' in identifying BAT, the defining thresholds used in terms of glucose uptake and adipose tissue identification from CT radiodensity vary tremendously (for review see [100,101]). Further, there are studies which have shown 18 FDG PET to be unreliable to measure BAT thermogenesis [42,65].…”