Given that macrophage infiltration into WAT has been reported to commonly occur during obesity (Weisberg et al., 2003), we determined the identity of the infiltrated cells by immunohistochemistry assays using the CD68 and CD163 macrophage markers (Barros et al., 2013; Fig. 3A). Here, CD163 is linked to obesity due to melanocortin 4 receptor deficiency.