A study of serum inflammatory markers and cytokines showed elevated serum concentration of high-sensitivity C-reactive protein, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8) in SA patients with ED, as compared with those without ED; this study supported the possible involvement of endothelial dysfunction in the development of ED in SA patients [41]. This evidence concerns the gene IL6 and endothelial dysfunction.