IL6 and obesity due to melanocortin 4 receptor deficiency: Higher serum levels of proinflammatory mediators, such as C-reactive protein, IL-6, and tumor necrosis factor α, as well as angiogenic factors, including VEGF, IGF-1, MMPs, and leptin, were observed in obese people compared with those in healthy people [15], and these factors are involved in the pathological changes of obesity.