NAMPT and obesity due to melanocortin 4 receptor deficiency: Obesity and increased fatty body tissue contribute to this inflammatory process, in which the production and release of adipokines involved in energy balance (resistin, leptin, visfatin), non-esterified fatty acids and pro-inflammatory cytokines, such as IL-6 and tumor necrosis factor-alpha (TNF-α), are directly related to the development of insulin resistance and MAFLD [20,42].