Fibroblast Growth Factor-21, Leptin and Adiponectin Responses to Acute Cold-induced Brown Adipose Tissue Activation.

BACKGROUND: Adipocyte-derived hormones play a role in insulin sensitivity and energy homeostasis. However, the relationship between circulating fibroblast growth factor 21 (FGF21), adipocytokines and cold-induced supraclavicular brown adipose tissue (sBAT) activation is underexplored.

OBJECTIVE: Our study aimed to investigate the relationships between cold-induced sBAT activity and plasma FGF21 and adipocytokines levels in healthy adults.

DESIGN: Nineteen healthy subjects underwent energy expenditure (EE) and supraclavicular infrared thermography (IRT) within a whole body calorimeter at baseline and at 2 hours post-cold exposure. 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/magnetic resonance (PET/MR) imaging scans were performed post-cold exposure. PET sBAT mean standardized uptake value (SUV mean), MR supraclavicular fat fraction (sFF), anterior supraclavicular maximum temperature (Tscv max) and EE change (%) after cold exposure were used to quantify sBAT activity.

MAIN OUTCOME MEASURES: Plasma FGF21, leptin, adiponectin and tumor necrosis factor-alpha (TNFα) at baseline and 2 hours post-cold exposure. Body composition at baseline by dual-energy X-ray absorptiometry (DXA).

RESULTS: Plasma FGF21 and adiponectin levels were significantly reduced post-cold exposure in BAT-positive subjects but not in BAT-negative subjects. Leptin concentration was significantly reduced in both BAT-positive and BAT-negative participants after cold exposure. Adiponectin concentration at baseline was positively strongly associated with sBAT PET SUV mean (coefficient=3269, P=0.01) and IRT Tscv max (coefficient=6801, P=0.03), and inversely correlated with MR sFF (coefficient=-404, P=0.02) after cold exposure in BAT-positive subjects but not in BAT-negative subjects.

CONCLUSION: Higher adiponectin concentrations at baseline indicate a greater cold-induced sBAT activity, which may be a novel predictor for sBAT activity in healthy BAT-positive adults.