Acute kidney injury and extrarenal organ dysfunction: new concepts and experimental evidence

Acute kidney injury (AKI) is a frequent complication in the intensive care unit with limited therapeutic modalities. Although survival from isolated AKI has improved with recent advancements in renal replacement therapy, mortality from AKI complicated by multiorgan dysfunction has remained unchanged and is estimated to be approximately 50%. Hence, defining and better understanding the pathophysiology of distant organ dysfunction associated with AKI is clinically important because it may lead to new treatment strategies. In animal models, it has become increasingly clear that AKI is not an isolated event but results in remote organ dysfunction involving the heart, lungs, liver, intestines, and brain through an inflammatory mechanism that involves neutrophil migration, cytokine expression, and increased oxidative stress. The purpose of this brief review is to summarize the human and basic science evidence for AKI and its detrimental effects on distant organs.