RETN and obesity due to melanocortin 4 receptor deficiency: Proinflammatory macrophage infiltration in adipose tissue increases in higher levels of obesity, and adipocytes secrete more proinflammatory factors such as leptin, visfactin, resistin, which activate nuclear factor kappa-B (NF-κB) and activator protein 1, thus producing more inflammatory factors such as TNF-α and interleukin-6, triggering obesity-related inflammation [56–58].