Renal fibrosis is the principal process underlying the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD). It is a relatively uniform response involving glomerulosclerosis, tubulointerstitial fibrosis and changes in renal vasculature (loss of glomerular and peritubular capillaries) ( Figure 1 ). Of these, tubulointerstitial fibrosis has evolved as the most consistent predictor of an irreversible loss of renal function and progression to ESRD [ 1 ].