SERPINE1 and obesity due to melanocortin 4 receptor deficiency: The infiltration of macrophages into adipose tissue is tightly bound with an excessive accumulation of fat in obesity and with the secretion of proinflammatory cytokines, such as plasminogen activator inhibitor-1 (PAI-1), tumor necrosis factor α (TNF-α), and interleukin6 (IL-6).