Detecting Validated Intracellular ROS Generation with ¹⁸F-dihydroethidine-Based PET.

Area of Science:

• Cardiovascular Research
• Biomedical Imaging
• Oxidative Stress Studies

Background:

• Reactive oxygen species (ROS) play a critical role in cardiac pathophysiology.
• Accurate detection of ROS is crucial for understanding and treating oxidative stress-related heart conditions.
• Existing methods for ROS detection may have limitations in ex vivo models.

Purpose of the Study:

• To assess the sensitivity of the 18F-radiolabeled dihydroethidine analogue ([18F]DHE) to ROS.
• To validate an ex vivo model of cardiac oxidative stress using [18F]DHE.
• To determine the utility of [18F]DHE for quantifying ROS in cardiac tissue.

Main Methods:

• In vitro characterization of [18F]DHE sensitivity to various ROS-generating systems.
• Perfusion of isolated rat hearts with monitoring of contractile function.
• Measurement of cardiac uptake of [18F]DHE under controlled ROS generation induced by menadione.
• Validation of ROS generation through parallel measures of cardiac oxidative stress markers.

Main Results:

• [18F]DHE demonstrated highest sensitivity to superoxide and hydroxyl radicals.
• Normalized [18F]DHE uptake was significantly elevated in menadione-treated hearts compared to controls (p < 0.05).
• Increased [18F]DHE uptake correlated with contractile dysfunction, glutathione depletion, and PKG1α dimerisation.

Conclusions:

• [18F]DHE serves as a sensitive reporter for ROS in a validated ex vivo model of cardiac oxidative stress.
• The tracer's pharmacokinetics are not significantly impacted by perfusion and tracer delivery in this model.
• [18F]DHE offers a reliable tool for investigating ROS in cardiac research.