Synchronous beating between xenografted human cardiomyocytes and host zebrafish embryonic hearts

Area of Science:

• Cardiology
• Regenerative Medicine
• Developmental Biology

Background:

• Human heart injuries result in fibrosis, hindering functional recovery.
• Zebrafish exhibit remarkable cardiac functional regeneration after injury.
• Significant species differences limit direct extrapolation of zebrafish regeneration mechanisms to humans.

Purpose of the Study:

• To establish a xenograft model using human induced pluripotent stem cell-derived cardiomyocytes (hiCMs) in zebrafish embryos.
• To investigate the behavior and integration of transplanted hiCMs within the zebrafish cardiac environment.
• To explore the potential of this model for bridging the cardiac regeneration gap between species.

Main Methods:

• Xenotransplantation of hiCMs into one-day post-fertilized zebrafish embryos.
• Establishment of a zebrafish xenograft model for studying hiCMs.
• Monitoring hiCMs using a genetically encoded calcium indicator (GCaMP) for beating activity.
• Analysis of GCaMP+ hiCMs beating synchronization within the host zebrafish heart.

Main Results:

• The xenograft model successfully allowed observation of transplanted hiCMs beating within zebrafish hearts.
• Synchronous beating between donor hiCMs and host zebrafish hearts was observed in 40% of cases.
• The model demonstrated the potential for functional integration of human cardiomyocytes in a vertebrate heart.

Conclusions:

• A novel zebrafish xenograft model using hiCMs was successfully established.
• The model facilitates the study of human cardiomyocyte behavior in a regenerative environment.
• This approach shows promise for understanding and potentially enhancing human cardiac regeneration.