CCL2 and obesity due to melanocortin 4 receptor deficiency: Two different studies using this mouse model present congruent data showing better insulin sensitivity, less proclivity for obesity development under high-fat diet feeding, reduced hepatic steatosis, and improved glucose tolerance together with less inflammation and lower plasma TNFα levels as well as reduced expression of inflammatory genes (Tnfα, and Ccl2) in the white fat [40,41].