Design and formulation of functional pluripotent stem cell-derived cardiac microtissues

Area of Science:

• Biomedical Engineering
• Stem Cell Biology
• Cardiovascular Research

Background:

• Developing accurate human cardiac tissue models is crucial for advancing heart disease drug discovery.
• Existing 3D models often struggle to replicate adult-like tissue fidelity and function.
• Human pluripotent stem cell (hPSC)-derived tissues offer potential but require optimized engineering.

Purpose of the Study:

• To engineer functional, aligned 3D cardiac microtissues (cardiac microwires, CMWs) using hPSCs.
• To optimize CMWs for enhanced maturation, electrical signal propagation, and drug responsiveness.
• To establish a predictive in vitro platform for cardiac electrophysiology and drug screening.

Main Methods:

• Utilized computational modeling of tissue mechanics to guide microtissue design.
• Employed microfabricated constraints for controlled self-assembly of hPSC-derived cardiac cells.
• Applied electromechanical stimuli, including aligned collagen and point stimulation pacing.
• Screened varying ratios of cardiomyocytes (NKX2-5+) and nonmyocytes (CD90+) for optimal tissue properties.

Main Results:

• Engineered aligned and functional cardiac microwires (CMWs) from hPSCs.
• Demonstrated that electromechanical stimuli and specific cell compositions enhance cardiac maturation.
• Identified an optimal ratio of 75% NKX2-5+ cardiomyocytes and 25% CD90+ nonmyocytes for superior tissue properties.
• Successfully modeled arrhythmogenesis in a tachycardic context, a feat not previously achieved in similar 3D models.

Conclusions:

• The cardiac microwire platform provides a high-fidelity, miniaturized model for human cardiac tissue.
• Optimized CMWs exhibit improved structural and functional properties, including in vivo-like electrical propagation.
• This platform accelerates the development of predictive in vitro assays for heart disease drug discovery and electrophysiology studies.