Pluripotent stem cells provide a potential solution to current epidemic rates of heart failure1 by providing human cardiomyocytes to support heart regeneration2. Studies of human embryonic-stem-cell-derived cardiomyocytes (hESC-CMs) in small-animal models have shown favourable effects of this treatment3,4,5,6,7. However, it remains unknown whether clinical-scale hESC-CM transplantation is feasible, safe or can provide sufficient myocardial regeneration. Here we show that hESC-CMs can be produced at a clinical scale (more than one billion cells per batch) and cryopreserved with good viability. Using a non-human primate model of myocardial ischaemia followed by reperfusion, we show that cryopreservation and intra-myocardial delivery of one billion hESC-CMs generates extensive remuscularization of the infarcted heart. The hESC-CMs showed progressive but incomplete maturation over a 3-month period. Grafts were perfused by host vasculature, and electromechanical junctions between graft and host myocytes were present within 2 weeks of engraftment. Importantly, grafts showed regular calcium transients that were synchronized to the host electrocardiogram, indicating electromechanical coupling. In contrast to small-animal models7, non-fatal ventricular arrhythmias were observed in hESC-CM-engrafted primates. Thus, hESC-CMs can remuscularize substantial amounts of the infarcted monkey heart. Comparable remuscularization of a human heart should be possible, but potential arrhythmic complications need to be overcome.
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We thank S. Dupras, B. Brown, D. Rocha, E. Wilson, C. English, J. Randolph-Habecker and T. Goodpaster for assistance with these experiments. This work was supported by National Institutes of Health grants P01HL094374, R01HL084642, U01HL100405 and P01GM081619 and an Institute of Translational Health Sciences/Primate Center Ignition Award. J.J.H.C. was supported by National Health and Medical Research Council of Australia Overseas Training and Australian-American Fulbright Commission Fellowships. X.Y. is supported by an American Heart Association post-doctoral scholarship 12POST11940060. J.J.W. is supported by an American Heart Association post-doctoral scholarship 12POST9330030. H.-P.K. is a Markey Molecular Medicine investigator and the recipient of the Jose Carreras/E.D. Thomas Chair for Cancer Research.
Extended data figures
Representative GCaMP3-expressing hESC-CMs were imaged using an inverted stereo-microscope with halogen and laser light sources. The video file shows the cardiomyocytes first by bright-field microscopy alone and then later with the green fluorescent signal. Note that the cells exhibit robust fluorescent transients with each contractile cycle.
Similar to Video S1, representative H7GCAMP3-hESC-CMs are shown first in bright field then with the green fluorescent signal. Note robust fluorescence with each cardiac cycle.
3-dimensional rendering of microcomputed tomography (same heart shown in Extended Data Fig. 9) animated with rotation to enable better visualization of the vessels within the graft. Arteries feeding the graft are red, other vessels are gray in the uninjured cardiac tissue, or white within the graft.
A harvested macaque heart is seen spontaneously beating after retrograde perfusion of with modified Tyrode’s solution. Electrodes are attached to the heart for electrocardiogram recording and analysis. Placement of the heart under a stereomicroscope with fluorescence imaging capabilities allows 2 visualization and analysis of epicardial fluorescence emitted from GCAMP3 expressing hESC-CM grafts.
A representative macaque heart with numerous GCaMP3-expressing hESC-CM graft regions, harvested at 28 days posttransplantation, mounted ex vivo on a Langendorff apparatus and mechanically arrested with 2,3-butanedione monoxime. This low power video (0.8x) shows several regions of GCaMP3-positive graft (distributed through infarct region and border zones) visible from the epicardial surface. All regions exhibited cyclic fluorescent transients that occurred in synchrony with QRS complexes of the host ECG, indicating 1:1 host-graft coupling. This video corresponds to Figure 2 b in main text.
Higher power of intravital imaging of the infarcted macaque heart with GCaMP3-expressing hESC-CM graft
This video shows the same heart as video S3 at higher (2x) magnification and corresponds to Figure 2c-d in main text.