TNF and endothelial dysfunction: Hypertensive patients with MetS have severe IR, together with elevated blood adipokines, such as leptin, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and resistin, which not only over-activate the sympathetic nervous system and rennin-angiotensin-aldosterone system, but also promote inflammation, endothelial dysfunction, and atherosclerosis4, 5, 6.