Functional video-based analysis of 3D cardiac structures generated from human embryonic stem cells.

Area of Science:

• Stem cell biology
• Cardiovascular research
• Biophysics

Background:

• Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) form complex 3D structures.
• Conventional electrophysiology methods like patch clamp and microelectrode arrays (MEAs) are unsuitable for these detached 3D cardiac clusters.
• Studying contractile function of these 3D structures is crucial for understanding cardiac development and disease.

Purpose of the Study:

• To develop a novel, non-invasive method for analyzing the contractile features of 3D hESC-CM clusters.
• To validate the efficacy of this method across different hESC differentiation protocols.
• To assess the potential of this method for high-throughput cardiotoxicity screening.

Main Methods:

• Development of a video-based motion detection software, cardiac beat rate analyzer (cBRA), utilizing optical flow by Farnebäck.
• Analysis of local displacement between sequential images to calculate beating characteristics.
• Characterization of hESC-CMs from two distinct differentiation protocols with differing morphologies and marker expression.

Main Results:

• cBRA reliably determined beat rates and beating variabilities in 3D cardiac clusters, irrespective of differentiation protocol.
• The software successfully identified functional responses, such as β-adrenoreceptor stimulation by isoproterenol.
• Subtle changes in beating features were detectable, demonstrating the method's sensitivity.

Conclusions:

• cBRA provides a robust and sensitive method for analyzing the contractile function of 3D hESC-CM clusters.
• This video-based approach overcomes limitations of conventional electrophysiology techniques for studying these structures.
• The developed cBRA software is suitable for high-throughput cardiotoxicity screening and functional characterization of cardiac cell models.