CCL2 and obesity due to melanocortin 4 receptor deficiency: The pathological state of obesity highly correlates with the circulating levels of adipocyte-specific adipokines, such as adiponectin, leptin, resistin, and visfatin, and NF-κB-responsive proinflammatory cytokines, such as tumor-necrosis factor-α (TNF-α), interleukin (IL)−1β, IL-6, and monocyte chemoattractant protein-1 (MCP-1).