Designing multicellular cardiac tissue engineering technologies for clinical translation

Cardiovascular diseases remain the leading cause of death worldwide—claiming one-third of all deaths every year. Current two-dimensional in vitro cell culture systems and animal models cannot completely recapitulate the clinical complexity of these diseases in humans. Therefore, there is a dire need for higher fidelity biological systems capable of replicating these phenotypes to inform clinical outcomes and therapeutic development. Cardiac tissue engineering (CTE) strategies have emerged to fulfill this need by the design of in vitro three-dimensional myocardial tissue systems from human pluripotent stem cells. In this way, CTE systems serve as highly controllable human models for a variety of applications—including for physiological and pathological modeling, drug discovery and preclinical testing platforms, and even direct therapeutic interventions in the clinic. Although significant progress has been made in the development of these CTE technologies, critical challenges remain and necessary refinements are required to derive more advanced human heart tissue technologies. In this review, we distill three focus areas for the field to address: I) Generating cardiac muscle cell types and scalable manufacturing methods, II) Engineering tissue structure, function, and analyses, and III) Curating system design for specific application. In each of our focus areas, we emphasize the importance of designing CTE systems capable of mimicking the intricate intercellular connectivity of the human heart and discuss fundamental design considerations that subsequently arise. We conclude by highlighting cutting-edge applications that use CTE technologies for clinical modeling and the direct repair of damaged and diseased hearts.