REN and acute kidney injury: Furthermore, mechanistically, the cytokines ADIPOQ, EGF, EGFR, REN and VEGF present in the urine of AKI stage 2/3 patients trigger processes such as angiogenesis that are needed to repair the damaged nephron and the activation of p53 and SIRT1 to maintain the balance between proliferation, angiogenesis, repair and cell-cycle arrest.