New insights into the mechanisms of acute kidney injury in the intensive care unit

• Acute kidney injury in the ICU contributes to increased mortality and morbidity in ICU patients.
• The causes of acute kidney injury are complex, and simply improving global renal blood flow may not be able to ameliorate acute kidney injury.
• We are describing new models of acute kidney injury that includes activation of inflammation and alterations in intrarenal blood flow.
• The interaction of inflammation and local blood flow changes may be better suited to explain how acute kidney injury ensues after ischemia-reperfusion injury.

Acute kidney injury is a frequent complication in the intensive care unit that is associated with increased mortality and morbidity. Traditional models consider reductions of global renal blood flow as the cause of acute kidney injury. However, a complex interplay between ischemia-reperfusion injury and inflammation may lead to intrarenal hypoperfusion and acute kidney injury. The role of changes of global renal blood flow as a cause for acute kidney injury remains controversial, especially in sepsis-induced acute kidney injury.