TNF and diabetes mellitus: Fat metabolism in diabetics also increases the production of proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) by multinucleated leukocytes and decreases the production of essential polypeptide growth factors such as platelet-derived growth factor (PDGF), transforming growth factor-beta 1 (TGF-β1) and fibroblast growth factor (bFGF) by tissue macrophages [6].