Visceral adipose tissue adiponectin predicts excess weight loss after bariatric surgery in females with severe obesity.

Objective: Bariatric surgery not always results in satisfactory excess weight loss (EWL) in severe obesity. Given the economic and clinical costs of bariatric surgery failure, defining predictors of successful EWL represents a relevant clinical issue for the health system to select patients benefiting from operation. Methods: By ELISA and Western blot analyses, we assessed the predicting value of pre-operative adiponectin (APN) locally produced in abdominal visceral (VAT) and subcutaneous (SAT) adipose tissue versus plasma levels as a novel sex-linked biomarker of EWL at different time points of follow up (6-24 months) after bariatric surgery in 43 patients (56% females) affected by severe obesity undergoing a small pilot observational study. Results: VAT-APN was lower in females and represented the only marker significantly correlated with EWL. In females, VAT-APN in the distribution upper quartile but not baseline BMI retained a statistically significant correlation with EWL at any time points (6-24 months) at multivariate analysis. The best VAT-APN cut-off value to predict 95% EWL at 12 months from surgery (98% accuracy, 100% sensitivity, 94% specificity, p = 0.010) was 5.1 µg/mg. Conclusions: In this very preliminary study, APN in VAT rather than its circulating or subcutaneous levels predicts EWL after bariatric surgery as an independent factor in the female sex only, thus contributing to identify those patients who could much benefit from surgery.