TNF and endothelial dysfunction: Perivascular adipose tissue (PVAT), a local deposit of adipocytes around blood vessels (which was not investigated in the current study), releases factors locally that can promote an anti‐contractile effect on vascular function.45 However, in obesity this does not happen as aberrant concentrations of factors, such as TNF‐alpha, downregulate endothelial NO synthase activity, causing endothelial dysfunction.46 Following bariatric surgery, levels of adipokines, such as adiponectin and NO, are normalized and PVAT anti‐contractile effects restored.