In Situ Expansion, Differentiation, and Electromechanical Coupling of Human Cardiac Muscle in a 3D Bioprinted, Chambered Organoid

Abstract

<jats:sec> <jats:title>Rationale:</jats:title> <jats:p>One goal of cardiac tissue engineering is the generation of a living, human pump in vitro that could replace animal models and eventually serve as an in vivo therapeutic. Models that replicate the geometrically complex structure of the heart, harboring chambers and large vessels with soft biomaterials, can be achieved using 3-dimensional bioprinting. Yet, inclusion of contiguous, living muscle to support pump function has not been achieved. This is largely due to the challenge of attaining high densities of cardiomyocytes—a notoriously nonproliferative cell type. An alternative strategy is to print with human induced pluripotent stem cells, which can proliferate to high densities and fill tissue spaces, and subsequently differentiate them into cardiomyocytes in situ.</jats:p> </jats:sec> <jats:sec> <jats:title>Objective:</jats:title> <jats:p>To develop a bioink capable of promoting human induced pluripotent stem cell proliferation and cardiomyocyte differentiation to 3-dimensionally print electromechanically functional, chambered organoids composed of contiguous cardiac muscle.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods and Results:</jats:title> <jats:p>We optimized a photo-crosslinkable formulation of native ECM (extracellular matrix) proteins and used this bioink to 3-dimensionally print human induced pluripotent stem cell–laden structures with 2 chambers and a vessel inlet and outlet. After human induced pluripotent stem cells proliferated to a sufficient density, we differentiated the cells within the structure and demonstrated function of the resultant human chambered muscle pump. Human chambered muscle pumps demonstrated macroscale beating and continuous action potential propagation with responsiveness to drugs and pacing. The connected chambers allowed for perfusion and enabled replication of pressure/volume relationships fundamental to the study of heart function and remodeling with health and disease.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p>This advance represents a critical step toward generating macroscale tissues, akin to aggregate-based organoids, but with the critical advantage of harboring geometric structures essential to the pump function of cardiac muscle. Looking forward, human chambered organoids of this type might also serve as a test bed for cardiac medical devices and eventually lead to therapeutic tissue grafting.</jats:p> </jats:sec>

Computational profiling of hiPSC-derived heart organoids reveals chamber defects associated with Ebstein’s anomaly

“…We note that this type of three-dimensional approach has advantages when studying heart developmental processes, especially chamber formation, compared to monolayer and co-differentiated microtissue systems. 33,34 We note that along the same lines Based on the sarcomere lengths and scRNA-seq data, we found the hiPSC derived CMs in both organoid and monolayer systems were relatively immature compared to primary cells. Additionally, we found the CMs in organoids were slightly less mature compared with CMs in monolayer system ( Figure S7, Supplementary Table 12).…”

Self-assembling human heart organoids for the modeling of cardiac development and congenital heart disease

“…Previous studies of microchamber formation in vitro utilized micropatterning of hPSCs into a con ned area to generate 3D cardiac microchambers with cell-free regions, a myo broblast perimeter, and nascent trabeculae 56 . Other reports have produced 3D bio-printed hPSC-laden scaffolds and differentiated them to beating cardiac microtissues with two chambers 57 . While the structures generated in these studies showed some fetallike formation of cardiac microchambers, they lacked endocardial tissue 10 , a crucial player in heart maturation and morphogenesis 58 .…”

Bioprinting of Collagen: Considerations, Potentials, and Applications

“…Additionally, others have made certain chemical modifications to enable photo‐crosslinking of collagen. [ 219,220 ] Recently, a team used riboflavin in combination with collagen to reduce gelation time and improve stability of constructs. [ 207 ] However, it is important with any future modifications to verify the cell viability to ensure that the bioink is still biocompatible and maintains the essential biocompatibility and structural functionalities intended for its application.…”