MPO and obesity due to melanocortin 4 receptor deficiency: In addition, our results were reinforced by Elgazar-Carmon et al. [63] and Wang et al. [64], who explained that neutrophils infiltrate adipose tissues in the early stage of HFD-induced obesity, promote macrophage infiltration, and release various substances, including reactive oxygen species, TNF-α, and MPO, all of which have the capacity to induce inflammation.