ATM and obesity due to melanocortin 4 receptor deficiency: ● Spatial and temporal variations are the basis for the infiltration of different ATM subpopulations, which also generate the M2a/M1 equilibrium. In lean subjects, M2a resides in interstitial region of AT but with developing obesity, infiltration of M1-like subtypes into necrotic adipocytes gets augmented; M1 are mainly appointed from circulation rather than conversion from M2a subtype of interstitial space.