CCL2 and type 2 diabetes mellitus: Compared to the AT of lean individuals, the AT of obese patients produces higher levels of pro-inflammatory adipokines—such as tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) [35], and monocyte chemoattractant protein-1 (MCP-1) [36]—which promote insulin resistance and strongly contribute to the development of T2D [37,38,39,40].