The contribution of omental adipose tissue to adipokine concentrations in patients with the metabolic syndrome

PURPOSE: To examine differences in peripheral vascular endothelial growth factor (VEGF), interleukin-6 (IL6) and cortisol concentrations between patients with both visceral obesity and metabolic syndrome, and lean controls. In a subsample of metabolic patients underwent abdominal surgery, the adipokine concentrations were measured in venous blood from the omentum to determine information on some processes of synthesis. METHODS: Forty-two healthy lean controls and 46 overweight-obese patients with central adiposity and stigmata of metabolic syndrome were studied. In a subsample of 11 metabolic patients undergoing non-bariatric surgery, blood samples from omental and peripheral veins were taken intraoperatively to determine VEGF, IL6 and cortisol concentrations. RESULTS: Median levels (range) of peripheral VEGF and IL6 were higher in patients than in controls 31.5 (3-112) pg/mL vs 21.35 (9-41.9) pg/mL (P < 0.05) and 5.50 (1.40-13) pg/mL vs 1.15 (0.3-1) pg/mL (P < 0.0001). On the other hand, concentrations of VEGF and IL6 from the omental and peripheral veins were similar in the surgery sub-group. Peripheral cortisol concentrations were not higher in patients than in controls, nor were omental concentrations different from the peripheral. Omental and peripheral VEGF and cortisol values were correlated, whereas no association was found between omental and peripheral IL6. CONCLUSIONS: In the presence of abdominal obesity, VEGF and IL6 concentrations are increased in the systemic circulation. The contribution of visceral adipose tissue to circulating levels of VEGF and IL6 was modest.