LTB4R and obesity due to melanocortin 4 receptor deficiency: Despite the increase in LTB4/LTBR1 being not only specific for obesity, it is well documented that LTB4 has a pivotal role in sustaining proinflammatory status in the context of obesity and insulin resistance (IR), due to its capacity to promote migration of the M1 macrophage when coupled to its receptor, referred to as LTB4R1 (10).