Hepatic–Renal Cascade Clearable Aminopeptidase N Probe for Rapid Detection of Early-Stage Liver Disease

Abstract Early liver disease is a prolonged process with vague symptoms and evolving pathological causes, leading to a delayed diagnosis and poor therapeutic outcomes. The development of rapid and effective approaches for liver disease detection in both preclinical research and clinical diagnosis is in high demand yet remains challenging. Herein, we report an activatable fluorogenic probe (CyP-A) that is cleared via a hepatic–renal cascade for monitoring of hepatocyte injury and tissue fibrosis. After systemic administration, CyP-A preferentially accumulates in the liver, where it undergoes APN-mediated cleavage and generates near-infrared fluorescence (NIRF), followed by renal excretion in urine. CyP-A allows NIRF detection of drug-induced liver injury (DILI) and nonalcoholic fatty liver disease (NAFLD) hours before histopathological confirmation via liver biopsy. CyP-A-based urinalysis can distinguish healthy mice from NAFLD mice with liver fibrosis, whereas conventional serological indicators of liver function fail to provide such discrimination. This noninvasive and sensitive test opens up new possibilities for early screening of liver disease.