CCL2 and kidney disorder: Among the oldest and most acknowledged mediators of renal disease are angiotensin II (Ang-II), transforming growth factor-β (TGF-β), platelet-derived growth factors (PDGFs), connective tissue growth factor (CTGF), endothelin-1 (ET-1), and key pro-inflammatory cytokines (e.g., MCP-1, TNF-α).