Disorders of metabolic homeostasis including type 2 diabetes, obesity, and dyslipidemias are characterized by both insulin resistance and endothelial dysfunction.1 Insulin resistance and endothelial dysfunction are also prominent features of important cardiovascular disorders including hypertension, coronary artery disease, and atherosclerosis.2 Indeed, insulin resistance is thought to be the tie that binds metabolic and cardiovascular disorders together in an unhappy union called the metabolic syndrome (aka the insulin resistance syndrome).3,4 Although these associations are well established, molecular mechanisms explaining the underlying pathophysiology are not completely understood. Interestingly, inflammation mediated by innate immune signaling pathways has been implicated in both metabolic insulin resistance and vascular endothelial dysfunction.1,5,6 In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology , Kim et al demonstrate that treatment of vascular endothelial cells with the free fatty acid (FFA) palmitate activates IKKβ (a proinflammatory signaling molecule), impairs insulin signaling, and decreases insulin-stimulated production of nitric oxide (NO).7 Importantly, inhibitory effects of FFA treatment on insulin signaling and NO production are blocked by overexpression of a dominant inhibitory mutant of IKKβ. Moreover, deleterious effects of FFA treatment are recapitulated by overexpression of wild-type IKKβ. Thus, Kim et al have uncovered an additional link between metabolic and vascular pathophysiology that helps to explain mechanisms underlying the metabolic syndrome and related cardiovascular diseases. To understand the importance of these findings it is …