Portal and systemic levels of visfatin in morbidly obese subjects undergoing bariatric surgery

The aim of the present study was to compare the levels of visfatin in portal and systemic circulations and to assess the possible relationship of visfatin with systemic inflammation and insulin resistance in morbidly obese patients undergoing bariatric surgery. A total of 46 morbidly obese patients (BMI = 45.3 ± 5.3 kg/m2) undergoing bariatric surgery were included in this study. Blood samplings were performed simultaneously from portal and systemic veins during surgery. Visfatin was measured in both portal and systemic venous samples. Besides, fasting serum levels of insulin, glucose, lipid profile, visfatin, and hs-CRP were determined in systemic venous blood samples. Insulin sensitivity was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). Visfatin concentrations were significantly higher in portal vein than systemic veins (11.9 ± 12.1 vs. 5.1 ± 3.3 ng/ml, p < 0.0001). While systemic levels of visfatin were significantly correlated with circulating levels of hs-CRP (r = 0.527, p < 0.0001), there were no significant correlations between portal levels of visfatin with systemic levels of hs-CRP concentrations. Substantially higher levels of visfatin in portal vein than systemic veins provide evidence that visceral adipose tissue is the major secretory source of visfatin in humans. Our findings underscore that visceral adipose tissue is an active endocrine organ that is involved in the complex interrelationship between obesity and pathologic conditions.