Manipulation of Cellular Excitability by Cell Fusion
Key result
Cell fusion of CHO-Kv4.3 cells into guinea pig cardiomyocytes successfully introduced a robust Ito1 current (16.5+/-2.6 pA/pF) that significantly accelerated early repolarization.
Population
Guinea pig cardiomyocytes
Comparison
Cell fusion with Chinese hamster ovary cells… vs Cell fusion with nontransfected CHO cells
Design
Preclinical
Authors
Discussion
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Implication
Cell fusion enables rapid Ito1 study in native myocytes; leaves open its role in repolarization pending further data.
Key Points
- This research aims to clarify the role of Ca2+-independent transient outward current (Ito1) in cardiac action potential repolarization.
- Cell fusion is utilized to introduce Ito1 into guinea pig cardiomyocytes using CHO cells expressing Kv4.3.
- Guinea pig cardiomyocytes were isolated, and functional ion channels were delivered within hours, allowing for rapid analysis.
- Fluorescent dye was used for cell identification, facilitating the examination of Ito1 effects on action potential dynamics.
- Myocytes fused with CHO-Kv4.3 exhibited a robust Ito1 of 16.5±2.6 pA/pF at +40 mV (n=19).
- Ito1 significantly accelerated early repolarization velocity (r=-0.68) and decreased voltage during the plateau phase (r=-0.90).
- The action potential duration reduced significantly with increased Ito1 density (r=-0.76 for 50% repolarization and r=-0.65 for 90% repolarization).
Structured PICO
P
Population
In vitro experimental study using cell fusion to introduce Ito1 into guinea pig cardiomyocytes.
I
Intervention
Cell fusion with Chinese hamster ovary (CHO) cells stably expressing Kv4.3 (CHO-Kv4.3) to introduce Ito1
C
Comparator
Cell fusion with nontransfected CHO cells
O
Outcome
Repolarization of the cardiac action potential (early repolarization velocity, plateau phase voltage, action potential duration)surrogate
Main Result
Absolute Event Rate: 16.5% vs 0%
Cell fusion successfully introduced functional Ito1 channels into guinea pig cardiomyocytes, demonstrating its significant role in accelerating early repolarization and abbreviating action potential duration.
Cite This Study
Hoppe et al. (1999) studied this question. Cell fusion with CHO cells stably expressing Kv4.3 vs. Cell fusion with nontransfected CHO cells was evaluated on Ito1 current density. Cell fusion of CHO-Kv4.3 cells into guinea pig cardiomyocytes successfully introduced a robust Ito1 current (16.5+/-2.6 pA/pF) that significantly accelerated early repolarization.