Functional and Pharmacological Differences Between the Contractility of axoCells™ iPSC-Derived Atrial and Ventricular Cardiomyocytes Assessed on the FLEXcyte 96

This application note from Axol Bioscience explores the functional and pharmacological differences between human iPSC-derived atrial (ax2518) and ventricular (ax2508) cardiomyocytes using the FLEXcyte 96 platform. With atrial fibrillation (AF) affecting over 33 million people globally, the need for physiologically relevant atrial models is critical.

Axol’s axoCells™ cardiomyocytes were assessed for contractility parameters including beat rate, beat duration, and waveform shape. The study demonstrates that atrial and ventricular cells respond differently to subtype-specific drugs, validating their use in AF research and drug development.

Key highlights include:

• Distinct contractility profiles:
  • Atrial cells show rounded waveforms; ventricular cells exhibit prolonged plateau phases
  • Differences reflect native cardiac action potential characteristics
• Drug response differentiation:
  • S-Bay K8644 (L-type Ca²⁺ agonist):
    • Prolongs beat duration in both cell types
    • Increases beat rate in ventricular cells; decreases in atrial cells
  • Carbachol (IKACh activator):
    • Reduces beat rate and prolongs beat duration in atrial cells only
    • Demonstrates functional IKACh activity in atrial cardiomyocytes
  • 4-Aminopyridine (4-AP) (IKur inhibitor):
    • Reduces beat rate and prolongs beat duration in atrial cells
    • No significant effect in ventricular cells
• Platform capabilities:
  • FLEXcyte 96 enables multiwell analysis of contractile force, beat rate, waveform shape, and arrhythmic events
  • PDMS membranes mimic native heart tissue elasticity

These findings confirm that axoCells™ atrial cardiomyocytes possess functional atrial-specific ion channels, making them ideal for modeling atrial-specific disorders such as AF. Combined with FLEXcyte 96, this system offers a powerful tool for in vitro drug screening and disease modeling.

Featured Axol Products:

• axoCells™ Atrial Cardiomyocytes (ax2518)
• axoCells™ Ventricular Cardiomyocytes (ax2508)