TNF and obesity due to melanocortin 4 receptor deficiency: These alterations may be attributable to the development of oxidative stress inducing pro-inflammatory adipokines from the visceral adipose tissue as well as to the linkage between obesity and elevated levels of pro-inflammatory cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) [19,20,21].