In this sense, we herein show that sleeve gastrectomy downregulated the mRNA synthesis of the proinflammatory factors MCP-1 and TNF-α in pancreata of the rats with diet-induced obesity, suggesting that this bariatric procedure might contribute to the polarization of macrophages towards a less proinflammatory state. The gene discussed is CCL2; the disease is obesity due to melanocortin 4 receptor deficiency.