Abstract 17000: Human Embryonic Stem Cell-Derived Cardiac Tissue Patch with Advanced Structure and Function
Human pluripotent stem cells are promising source for cell therapies and drug screening. We explored how seeding purity of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) affects functionality of engineered cardiac tissues. Cells dissociated from differentiating embryoid bodies were quantified for the percent of SIRPA+ hESC-CMs using FACS. 3D tissue patches were made by seeding 106 cells in a fibrin-based hydrogel matrix. After 8 days, patches were assessed by immunostaining, optical mapping of action potential conduction, and isometric tests of generated contractile force. The patches contained highly aligned, cross-striated, and electromechanically coupled hESC-CMs interspersed with vimentin+ and SM22α+ non-myocytes (A). hESC-CMs in tissue patches supported macroscopically continuous electrical propagation (B) with conduction velocity (CV) that increased with cardiomyocyte purity (C), reaching 19.5 cm/s for 80% seeded CMs. For a given seeding purity (48-65%), 3D patches exhibited higher CVs and action potential durations (APDs) than age-matched 2D monolayers (8.9±0.9 vs. 5.3±0.8 cm/s and 339±62 vs. 250±48 ms, D). The maximum rate of capture (MCR) during point pacing in tissue patches averaged to 2.9±0.4 Hz (E). Contractile force amplitudes depended biphasically on the CM purity (F) and increased with applied strains in a Starling-like fashion (not shown). The maximum contractile forces averaged to 3.1±1.2 mN yielding specific forces of 11.1±4.3 mN/mm2. Overall, the described human cardiac tissue patches exhibited unprecedented levels of functional maturity. We also conclude that the seeding purity of hESC-CMs is an important determinant of both electrical and mechanical function of the patch.
- © 2012 by American Heart Association, Inc.