Acute kidney injury after hepatic ischemia and reperfusion injury in mice

Hepatic ischemia reperfusion (IR) is the leading cause of acute liver failure (ALF) during the perioperative period and patients with ALF frequently develop acute kidney injury (AKI). There is no effective therapy for AKI associated with ALF because pathomechanisms are incompletely characterized, in part due to the lack of an animal model. In this study, we characterize a novel murine model of AKI following hepatic IR. Mice subjected to ~70% liver IR not only developed acute liver dysfunction, but also developed severe AKI 24 hr after liver injury. Mice subjected to liver IR developed histological changes of acute tubular injury including focal proximal tubular cell necrosis involving the S3 segment, cortical tubular ectasia, focal tubular simplification and granular bile/heme cast formation. In addition, there was focal interstitial edema and hyperplasia of the juxtaglomerular apparatus. Inflammatory changes in the kidney after hepatic IR included neutrophil infiltration of the interstitium and upregulation of several pro-inflammatory mRNAs (tumor necrosis factor-α, keratinocyte derived cytokine, monocyte chemotactic protein-1, macrophage inflammatory protein-2, intercellular adhesion molecule-1). In addition, marked renal endothelial cell apoptosis was detected involving peritubular interstitial capillaries, accompanied by increased renal vascular permeability. Finally, there was severe disruption of renal proximal tubule epithelial filamentous-actin. Our results show that AKI rapidly and reproducibly develops in mice after hepatic IR and is characterized by renal tubular necrosis, inflammatory changes and interstitial capillary endothelial apoptosis. Our murine model of AKI after liver injury closely mimics human AKI associated with ALF and may be useful in delineating the mechanisms and potential therapies for this common clinical condition.