In Vivo Monitoring of Hepatic Ischemia Using a Dual-Enzyme Activated Near-Infrared Fluorescence Probe

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Translational Medicine

Background:

• Hepatic ischemia-reperfusion injury (HIRI) is a critical complication in liver transplantation, leading to graft dysfunction and rejection.
• Current diagnostic methods often focus on oxidative stress post-reperfusion, neglecting early ischemic damage characterized by hypoxia.
• Hypoxia-specific biomarkers are underexplored for early HIRI detection.

Purpose of the Study:

• To develop a novel near-infrared (NIR) fluorescent probe for early, specific detection of hepatic ischemia.
• To enable real-time visualization of hypoxic injury prior to reperfusion in vivo.
• To differentiate ischemic damage from reperfusion-induced oxidative stress.

Main Methods:

• Development of QN-NIR, a dual-activated NIR fluorescent probe.
• Design for activation by hypoxia-associated reductases: human NAD(P)H:quinone oxidoreductase 1 (hNQO1) and nitroreductases (NTRs).
• In vivo imaging of hepatic ischemia in a preclinical model.

Main Results:

• QN-NIR exhibits dual-enzyme activation under hypoxic conditions, producing a strong Off-On NIR fluorescence response at 708 nm.
• The dual-enzyme strategy ensures high signal-to-noise ratio with minimal false positives under normoxia.
• QN-NIR successfully visualized hepatic ischemia in real-time prior to reperfusion in vivo.

Conclusions:

• QN-NIR is a promising fluorescent probe for precise, noninvasive early diagnosis of hepatic ischemia.
• Hypoxia is a key, targetable feature of ischemic injury, detectable by QN-NIR.
• This probe platform facilitates distinguishing ischemic injury from reperfusion-related oxidative stress.