CCL2 and diabetic kidney disease: A growing number of reviews present a common consensus that adhesion molecules (e.g., intercellular cell adhesion molecule (ICAM)-1), diverse inflammatory cytokines (e.g., interleukin (IL)-1, IL-6, IL-18, and tumor necrosis factor-alpha (TNF-α)), and chemokines (e.g., monocyte chemotactic protein-1 (MCP-1)/chemokine C-C motif ligand 2 (CCL2), C-X3-C motif chemokine (CX3CL1), and CCL5/RANTES) are involved in the pathogenesis of DKD.