Figure 4: Link of adipocytes and pancreatic β cells. FFAs released by adipocytes suppress insulin synthesis and conversion of proinsulin to insulin, induce mitochondria dysfunction with increased ROS production and promote ER stress. Adipocytes produce proinflammatory cytokines including PAI-1, TNF-α, and MCP-1 and inflammatory adipokine resistin. TGF β1 not only inhibits insulin transcription but also participates with proinflammatory cytokines and resistin in inflammation. The cytokines-mediated inflammation could be both NF-kB dependent and independent. Leptin reduces insulin synthesis. Different from other adipokines and cytokines, adiponectin protects β cell death and stimulates insulin release. The role of IL-6 seems to have double sword effects that wait for further investigation.