Epigenetic Changes in the Acute Kidney Injury-to-Chronic Kidney Disease Transition

Previously acute kidney injury (AKI) had been believed to be a transient event, and recovery from AKI had been thought to lead to no consequences. However, recent epidemiological studies have shown that even if there is complete recovery of the kidney function, AKI can eventually result in chronic kidney disease (CKD) and eventually in end-stage kidney disease in the long term. Transition of AKI to CKD is mediated by multiple mechanisms, including aberrant cell cycle arrest and hypoxia. Hypoxia of the kidney is induced by rarefaction of the peritubular capillaries after AKI episodes, and induces inflammation and fibrosis. It should also be noted that epigenetic changes are closely related to hypoxia, and epigenetic changes induced by hypoxia, called “hypoxic memory” can explain the AKI-to-CKD transition in the long term after complete recovery from the initial AKI episode. Targeting hypoxia and subsequent epigenetic changes are promising strategies to block the transition from AKI to CKD.