Wu et al showed that Twist1 plays a critical role in macrophage-myofibroblast transdifferentiation (MMT) in unilateral ureteral obstruction (UUO) model kidneys, and MCP-1/CCR2 axis is likely to be one of the main pathways leading to Twist1-mediated UUO renal fibrosis.[39] A biopsy study showed that patients with active fibrotic nephropathy, CD68+αSMA + cells, and intermediate MMT, were found to have active fibrotic nephropathy. This evidence concerns the gene CCR2 and renal fibrosis.