CCL2 and obesity due to melanocortin 4 receptor deficiency: The expression of monocyte chemoattractant protein-1 (Mcp-1), a chemokine that serves as marker for obesity-associated inflammation, was unchanged in iBAT, slightly elevated in iWAT, and significantly downregulated in eWAT of sildenafil-treated animals (P = 0.0406, Fig. 1g-i).