Effects of weight loss on visceral and abdominal subcutaneous adipose tissue blood-flow and insulin-mediated glucose uptake in healthy obese subjects

Objective. Rapid weight loss with very-low-calorie diet (VLCD) is known to improve insulin sensitivity and decrease adipose tissue masses. The aim was to investigate the effects of VLCD on adipose tissue regional glucose uptake (rGU) and perfusion and their association with adipokines. Research design and methods. Sixteen healthy obese (body mass index 331.1 kg/m2) subjects underwent VLCD for 6 weeks. RGU and perfusion were measured using [18F]-fluoro-deoxy-glucose, [15O]H2O and positron emission tomography. Results. Blood-flow and rGU expressed per gram of adipose tissue were higher in visceral fat compared to abdominal subcutaneous fat (P0.01 for both). Dieting decreased weight by 110.9 kg (P0.0001). Visceral adipose fat decreased by 25% (P0.001) and abdominal subcutaneous fat by 16% (P0.001). Whole body insulin sensitivity increased by 33% (P0.01). Perfusion of both fat depots decreased (P0.001), while rGU remained unchanged. Among the adipokines, leptin and interleukin-6 levels seemed to be associated with abdominal subcutaneous and intra-abdominal adipose tissue insulin resistance but not with adipose tissue perfusion. Conclusions. Abdominal adipose tissue perfusion and rGU are not related in obesity. Rapid weight loss decreases perfusion through adipose tissue depots but has no influence on rGU demonstrating the 'sink' role of adipose tissue.