RETN and obesity due to melanocortin 4 receptor deficiency: Inflammation in obesity is manifested by increased circulating levels of classical pro-inflammatory cytokines, such as TNF and altered levels of adipokines, including leptin, resistin, and adiponectin (Tilg and Moschen, 2006; Lumeng and Saltiel, 2011; Pavlov and Tracey, 2012).