TNF and endothelial dysfunction: Interestingly, same previous study [18] found that IL-6 mRNA and protein expressions were significantly reduced in dbTNF-/dbTNF- mice suggesting TNF-α could be a mediator of IL-6, but the interactive relationship between TNF-α and IL-6 contributing to the endothelial dysfunction of coronary microcirculation in T2D has not been clearly established yet.