Pathway from Acute Kidney Injury to Chronic Kidney Disease: Molecules Involved in Renal Fibrosis

Acute kidney injury (AKI) is one of the main conditions responsible for chronic kidney disease (CKD), including end-stage renal disease (ESRD) as a long-term complication. Besides short-term complications, such as electrolyte and acid-base disorders, fluid overload, bleeding complications or immune dysfunctions, AKI can develop chronic injuries and subsequent CKD through renal fibrosis pathways. Kidney fibrosis is a pathological process defined by excessive extracellular matrix (ECM) deposition, evidenced in chronic kidney injuries with maladaptive architecture restoration. So far, cited maladaptive kidney processes responsible for AKI to CKD transition were epithelial, endothelial, pericyte, macrophage and fibroblast transition to myofibroblasts. These are responsible for smooth muscle actin (SMA) synthesis and abnormal renal architecture. Recently, AKI progress to CKD or ESRD gained a lot of interest, with impressive progression in discovering the mechanisms involved in renal fibrosis, including cellular and molecular pathways. Risk factors mentioned in AKI progression to CKD are frequency and severity of kidney injury, chronic diseases such as uncontrolled hypertension, diabetes mellitus, obesity and unmodifiable risk factors (i.e., genetics, older age or gender). To provide a better understanding of AKI transition to CKD, we have selected relevant and updated information regarding the risk factors responsible for AKIs unfavorable long-term evolution and mechanisms incriminated in the progression to a chronic state, along with possible therapeutic approaches in preventing or delaying CKD from AKI.