Short-term cold acclimation recruits brown adipose tissue in obese humans

Recruitment of brown adipose tissue (BAT) has emerged as a potential tool to combat obesity and associated metabolic complications. Short-term cold acclimation has been shown to not only enhance BAT presence and activity in lean humans, but also improve skeletal muscle metabolic profile to benefit glucose uptake in type 2 diabetic patients. Here, we examined whether short-term cold acclimation also induced such adaptations in ten metabolically healthy obese male subjects. A 10-day cold acclimation period resulted in increased cold-induced glucose uptake in BAT, as assessed by [18F]FDG-PET/CT scanning. BAT activity was negatively related to age, with a similar trend for body fat%. In addition, cold-induced glucose uptake in BAT was positively related to glucose uptake in visceral WAT, although glucose uptake in visceral and subcutaneous WAT depots was unchanged upon cold acclimation. Cold-induced skeletal muscle glucose uptake tended to increase upon cold acclimation, which was paralleled by increased basal GLUT4 localization in the sarcolemma, as assessed in muscle biopsies. Proximal skin temperature was increased and subjective responses to cold were slightly improved at the end of the acclimation period. These metabolic adaptations to prolonged mild cold exposure may lead to improved glucose metabolism or prevent development of obesity-associated insulin resistance and hyperglycemia. TRIAL REGISTRATION NUMBER: NTR4319.