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Updated: Jul 17, 2026
Confocal Imaging of Single Mitochondrial Superoxide Flashes in Intact Heart or In Vivo
Published on: November 5, 2013
Real-time imaging of apoptotic cell-membrane changes at the single-cell level in the beating murine heart
E A Dumont1, C P Reutelingsperger, J F Smits
1Cardiovascular Research Institute Maastricht, Universiteitssingel 50, Maastricht, the Netherlands.
Abstract:
We report a novel real-time imaging model to visualize apoptotic membrane changes of single cardiomyocytes in the injured heart of the living mouse, using fluorescent labeled annexin-V. Annexin-V binds to externalized phosphatidylserine (PS) of cells undergoing programmed cell death. With high-magnification (x100-160) real-time imaging, we visualized the binding of annexin-V to single cardiomyocytes. Kinetic studies at the single-cell level revealed that cardiomyocytes started to bind annexin-V within minutes after reperfusion, following an ischemic period of 30 minutes. The amount of bound annexin-V increased rapidly and reached a maximum within 20-25 minutes. Caspase inhibitors decreased the number of annexin-V-positive cardiomyocytes and slowed down the rate of PS exposure of cardiomyocytes that still bound annexin-V. This technology to study cell biology in the natural environment will enhance knowledge of intracellular signaling pathways relevant for cell-death regulation and strategies to manipulate these pathways for therapeutic effect.
Insights
This study introduces a new real-time imaging method to observe cell death in heart cells. The technique visualizes phosphatidylserine exposure during apoptosis, aiding the development of heart disease therapies.
Area of Science:
- Cardiovascular Biology
- Cell Death Mechanisms
- In Vivo Imaging
Background:
- Apoptosis, or programmed cell death, is crucial in cardiac injury.
- Visualizing apoptotic changes in cardiomyocytes in real-time is challenging.
- Annexin-V is a biomarker for externalized phosphatidylserine (PS) during apoptosis.
Purpose of the Study:
- To develop and validate a novel real-time imaging model for visualizing apoptotic membrane changes in single cardiomyocytes.
- To investigate the kinetics of phosphatidylserine exposure in cardiomyocytes following cardiac injury in vivo.
- To assess the impact of caspase inhibitors on cardiomyocyte apoptosis.
Main Methods:
- High-magnification (x100-160) real-time imaging of living mouse hearts.
- Utilizing fluorescently labeled annexin-V to detect externalized phosphatidylserine on cardiomyocytes.
- Performing kinetic studies at the single-cell level post-ischemia and reperfusion.
- Administering caspase inhibitors to evaluate their effect on apoptosis.
Main Results:
- Successfully visualized annexin-V binding to single cardiomyocytes in real-time.
- Cardiomyocytes began binding annexin-V within minutes of reperfusion after 30 minutes of ischemia.
- Annexin-V binding increased rapidly, peaking within 20-25 minutes.
- Caspase inhibitors reduced the number of annexin-V-positive cardiomyocytes and slowed PS exposure.
Conclusions:
- The novel imaging model enables real-time visualization of cardiomyocyte apoptosis in vivo.
- This technology provides insights into the temporal dynamics of cell death signaling pathways.
- Understanding these pathways can inform therapeutic strategies for cardiac protection and regeneration.
