Transplantation Of Cardiomyocytes Research Articles

Hemodynamic Melody of Postnatal Cardiac and Pulmonary Development in Children with Congenital Heart Diseases.

Hemodynamics is the eternal theme of the circulatory system. Abnormal hemodynamics and cardiac and pulmonary development intertwine to form the most important features of children with congenital heart diseases (CHDs), thus determining these children's long-term quality of life. Here, we review the varieties of hemodynamic abnormalities that exist in children with CHDs, the recently developed neonatal rodent models of CHDs, and the inspirations these models have brought us in the areas of cardiomyocyte proliferation and maturation, as well as in alveolar development. Furthermore, current limitations, future directions, and clinical decision making based on these inspirations are highlighted. Understanding how CHD-associated hemodynamic scenarios shape postnatal heart and lung development may provide a novel path to improving the long-term quality of life of children with CHDs, transplantation of stem cell-derived cardiomyocytes, and cardiac regeneration.

Transplantation of induced pluripotent stem cells-derived cardiomyocytes combined with modified Taohong Siwu decoction improved heart repair after myocardial infarction

ObjectiveThis study aimed to study whether modified Taohong Siwu decoction (MTHSWD) combined with human induced pluripotent stem cells-derived cardiomyocytes (iPS-CMs) transplantation can promote cardiac function in myocardial infarction (MI) nude mouse model and explore its possible mechanism. MethodsThe MI mouse model was established by the ligation of left anterior descending coronary artery. After 4 weeks of gavage of MTHSWD combined with iPS-CMs transplantation, the changes in heart function of mice were examined by echocardiography. The histological changes were observed by Masson's trichrome staining. The survival and differentiation of transplanted cells were detected by double immunofluorescence staining of human nuclear antigen (HNA) and cardiac troponin T (cTnT). The number of c-kit-positive cells in the infarct area were evaluated by immunofluorescent staining. The levels of stromal cell-derived factor 1 (SDF-1), stem cell factor (SCF), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor in infarcted myocardium tissues were detected by ELISA. ResultsMTHSWD combined with iPS-CMs transplantation can improve the heart function of MI mice, reduce the infarct size and collagen deposition in infarct area. By immunofluorescence double-label detection of HNA and cTnT, it was found that MTHSWD combined with iPS-CMs transplantation can improve the survival and maturation of iPS-CMs. In addition, MTHSWD combined with iPS-CMs transplantation can activate more endogenous c-kit positive cardiac mesenchymal cells, and significantly increase the content of SDF-1, SCF and VEGF in myocardial tissues. ConclusionsThe combination of MTHSWD with iPS-CMs transplantation promoted cardiac function of nude mice with MI by improving the survival and maturation of iPS-CMs in the infarct area, activating the endogenous c-kit positive cardiac mesenchymal cells, and increasing paracrine.

Nanotechnology Innovations in Pediatric Cardiology and Cardiovascular Medicine: A Comprehensive Review.

(1) Background: Nanomedicine, incorporating various nanoparticles and nanomaterials, offers significant potential in medical practice. Its clinical adoption, however, faces challenges like safety concerns, regulatory hurdles, and biocompatibility issues. Despite these, recent advancements have led to the approval of many nanotechnology-based products, including those for pediatric use. (2) Methods: Our approach included reviewing clinical, preclinical, and animal studies, as well as literature reviews from the past two decades and ongoing trials. (3) Results: Nanotechnology has introduced innovative solutions in cardiovascular care, particularly in managing myocardial ischemia. Key developments include drug-eluting stents, nitric oxide-releasing coatings, and the use of magnetic nanoparticles in cardiomyocyte transplantation. These advancements are pivotal for early detection and treatment. In cardiovascular imaging, nanotechnology enables noninvasive assessments. In pediatric cardiology, it holds promise in assisting the development of biological conduits, synthetic valves, and bioartificial grafts for congenital heart defects, and offers new treatments for conditions like dilated cardiomyopathy and pulmonary hypertension. (4) Conclusions: Nanomedicine presents groundbreaking solutions for cardiovascular diseases in both adults and children. It has the potential to transform cardiac care, from enhancing myocardial ischemia treatment and imaging techniques to addressing congenital heart issues. Further research and guideline development are crucial for optimizing its clinical application and revolutionizing patient care.

Casein Kinase 1 Phosphomimetic Mutations Negatively Impact Connexin-43 Gap Junctions in Human Pluripotent Stem Cell-Derived Cardiomyocytes.

The transplantation of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) has shown promise in preclinical models of myocardial infarction, but graft myocardium exhibits incomplete host-graft electromechanical integration and a propensity for pro-arrhythmic behavior. Perhaps contributing to this situation, hPSC-CM grafts show low expression of connexin 43 (Cx43), the major gap junction (GJ) protein, in ventricular myocardia. We hypothesized that Cx43 expression and function could be rescued by engineering Cx43 in hPSC-CMs with a series of phosphatase-resistant mutations at three casein kinase 1 phosphorylation sites (Cx43-S3E) that have been previously reported to stabilize Cx43 GJs and reduce arrhythmias in transgenic mice. However, contrary to our predictions, transgenic Cx43-S3E hPSC-CMs exhibited reduced Cx43 expression relative to wild-type cells, both at baseline and following ischemic challenge. Cx43-S3E hPSC-CMs showed correspondingly slower conduction velocities, increased automaticity, and differential expression of other connexin isoforms and various genes involved in cardiac excitation-contraction coupling. Cx43-S3E hPSC-CMs also had phosphorylation marks associated with Cx43 GJ internalization, a finding that may account for their impaired GJ localization. Taken collectively, our data indicate that the Cx43-S3E mutation behaves differently in hPSC-CMs than in adult mouse ventricular myocytes and that multiple biological factors likely need to be addressed synchronously to ensure proper Cx43 expression, localization, and function.

Quiescent-yet-excitable pluripotent stem cell-derived cardiomyocytes engraft without fatal arrhythmias in minipig and primates

Abstract Background Pluripotent stem cell-derived cardiomyocyte (PSC-CM) transplantation is a promising therapy for subacute myocardial infarction (MI), but transient engraftment-related arrhythmia (EA) is major barrier to clinical development (1, 2). We hypothesize that PSC-CM genetically edited to remove automaticity but otherwise functionally intact will engraft in vivo with greater arrhythmic safety. Methods Combinatorial CRISPR/Cas9 genome editing to screen for electrically quiescent PSC-CM yielded a line deficient in the depolarization-associated genes HCN4, CACNA1H, and SLC8A1, combined with overexpression of the hyperpolarization-associated gene KCNJ2. Initially, we transplanted 150 million (n=3) and 500 million gene-edited (n=2) and 150 million wildtype (n=7) PSC-CMs into a minipig model of EA, and we monitored the animals for up to seven weeks on continuous ECG for arrythmia without anti-arrhythmic therapy. In a second study, we transplanted 750 million gene-edited (n=2) and wildtype (n=1) PSC-CMs into sub-acutely infarcted Macaca nemestrina primates. Sham transplant (n=1) was also performed, and all animals were observed for up to three months with immunosuppression and beta-blocker/amiodarone therapy. Results Gene-edited PSC-CM successfully engrafted and structurally coupled with the host myocardium of minipigs (Figure 1) and nonhuman primates (Figure 2). No significant EA occurred after transplanting edited PSC-CM at the 150 million dose, whereas brief EA (<24 hours) was observed and well tolerated at the higher 500 million dose. All five minipigs survived to prespecified timepoints without complication. Conversely, wildtype PSC-CM controls demonstrated uncontrolled and fatal ventricular tachycardia (VT). Of the seven WT control minipigs, only four survived (43% mortality); three expired or were euthanized due to unstable VT or ventricular fibrillation. Arrythmia burden for both 150 and 500 million doses were significantly reduced compared to the 150 million wildtype dose in the first 30-days post-transplant (p<0.0001 for both). We then tested edited PSC-CM in a clinically relevant nonhuman primate model of sub-acute myocardial infarction using standard medical therapy including modest antiarrhythmic therapy. No arrythmia was noted in both nonhuman primates dosed with 750 million edited PSC-CM whereas significant arrhythmia was observed with wildtype despite beta blocker and amiodarone therapy. All pig and primate grafts were structurally coupled with host myocardium. Conclusion Genetically-edited PSC-CM without pacemaker-like activity significantly reduced arrythmia burden and prevented arrhythmic death in a dose-escalation study in minipig. No arrhythmia was observed in a clinically relevant nonhuman primate model of cardiac remuscularization for sub-acute myocardial infarction. This study supports continued investigation of this novel strategy to improve safety and tolerability of PSC-CM transplantation.Edited PSC-CM transplant in minipigEdited PSC-CM transplant in primates

In vivo tracking transplanted cardiomyocytes derived from human induced pluripotent stem cells using nuclear medicine imaging.

Transplantation of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) is a promising treatment for heart failure. Information on long-term cell engraftment after transplantation is clinically important. However, clinically applicable evaluation methods have not yet been established. In this study, to noninvasively assess transplanted cell engraftment, human SLC5A5, which encodes a sodium/iodide symporter (NIS) that transports radioactive tracers such as 125I, 18F-tetrafluoroborate (TFB), and 99mTc-pertechnetate (99mTcO4-), was transduced into human induced pluripotent stem cells (iPSCs), and nuclear medicine imaging was used to track engrafted human iPSC-CMs. To evaluate the pluripotency of NIS-expressing human iPSCs, they were subcutaneously transplanted into immunodeficient rats. Teratomas were detected by 99mTcO4- single photon emission computed tomography (SPECT/CT) imaging. NIS expression and the uptake ability of 125I were maintained in purified human iPSC-CMs. NIS-expressing human iPSC-CMs transplanted into immunodeficient rats could be detected over time using 99mTcO4- SPECT/CT imaging. Unexpectedly, NIS expression affected cell proliferation of human iPSCs and iPSC-derived cells. Such functionally designed iPSC-CMs have potential clinical applications as a noninvasive method of grafted cell evaluation, but further studies are needed to determine the effects of NIS transduction on cellular characteristics and functions.

Dual Gene-Loaded Near-Infrared AIEgen Nanoplatforms with Promoted Proliferation, Relieved Immunosuppression, and Tracking Capabilities for Cardiomyocyte Transplantation

Dual Gene-Loaded Near-Infrared AIEgen Nanoplatforms with Promoted Proliferation, Relieved Immunosuppression, and Tracking Capabilities for Cardiomyocyte Transplantation

CCR2 macrophage response determines the functional outcome following cardiomyocyte transplantation

BackgroundThe immune response is a crucial factor for mediating the benefit of cardiac cell therapies. Our previous research showed that cardiomyocyte transplantation alters the cardiac immune response and, when combined with short-term pharmacological CCR2 inhibition, resulted in diminished functional benefit. However, the specific role of innate immune cells, especially CCR2 macrophages on the outcome of cardiomyocyte transplantation, is unclear.MethodsWe compared the cellular, molecular, and functional outcome following cardiomyocyte transplantation in wildtype and T cell- and B cell-deficient Rag2del mice. The cardiac inflammatory response was assessed using flow cytometry. Gene expression profile was assessed using single-cell and bulk RNA sequencing. Cardiac function and morphology were determined using magnetic resonance tomography and immunohistochemistry respectively.ResultsCompared to wildtype mice, Rag2del mice show an increased innate immune response at steady state and disparate macrophage response after MI. Subsequent single-cell analyses after MI showed differences in macrophage development and a lower prevalence of CCR2 expressing macrophages. Cardiomyocyte transplantation increased NK cells and monocytes, while reducing CCR2−MHC-IIlo macrophages. Consequently, it led to increased mRNA levels of genes involved in extracellular remodelling, poor graft survival, and no functional improvement. Using machine learning-based feature selection, Mfge8 and Ccl7 were identified as the primary targets underlying these effects in the heart.ConclusionsOur results demonstrate that the improved functional outcome following cardiomyocyte transplantation is dependent on a specific CCR2 macrophage response. This work highlights the need to study the role of the immune response for cardiomyocyte cell therapy for successful clinical translation.

Abstract P1066: Engineering Of Ferritin Overexpressing Human Induced Pluripotent Stem Cells For In Vivo Tracking Of Grafts Using Magnetic Resonance Imaging

Introduction: Transplantation of human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs) emerges as a promising approach for the treatment of heart diseases. However, it is an unmet challenge to precisely localize the hiPSC-CMs upon transplantation and quantify the graft size in the live large animals. To address this issue, we established a new approach to track grafted CMs in large animals using magnetic resonance imaging detectable reporter molecules, which allows the assessment of graft size in live animals at different time points. Methods: We employed a CRISPR/Cas9 system as a virus-free approach to overexpress ferritin in hiPSCs. Results: hiPSC cells were transfected with ferritin heavy chain CRISPR activation plasmid for 24 hours. Before antibiotic selection, we established a kill curve to determine the appropriate antibiotic concentration. Based on the kill curve, we conducted antibiotic selection using puromycin for 7 days and isolated transfected colonies for further culture. Next, we treated various concentrations of iron chloride (0-100 μM) to the FHC transfected hiPSC for 4 hours to examine a proper concentration of iron loading for MRI detection. There was no significant difference in cell viability between 0 and 25 μM of iron chloride. In addition, we confirmed transfection efficiency with higher ferritin expression in transfected cells compared to controls (non-transfected wild-type hiPSC). Following, we plan to differentiate ferritin overexpressing hiPSC into cardiomyocytes, inject the cells into porcine hearts, and conduct magnetic resonance imaging to detect the engrafted transgenic cells in live animals. Conclusion: The ferritin-expressing hiPSC line has the potential to provide a reliable measurement of the graft size in large animals.

Nanowired human cardiac organoid transplantation enables highly efficient and effective recovery of infarcted hearts.

Human cardiac organoids hold remarkable potential for cardiovascular disease modeling and human pluripotent stem cell-derived cardiomyocyte (hPSC-CM) transplantation. Here, we show cardiac organoids engineered with electrically conductive silicon nanowires (e-SiNWs) significantly enhance the therapeutic efficacy of hPSC-CMs to treat infarcted hearts. We first demonstrated the biocompatibility of e-SiNWs and their capacity to improve cardiac microtissue engraftment in healthy rat myocardium. Nanowired human cardiac organoids were then engineered with hPSC-CMs, nonmyocyte supporting cells, and e-SiNWs. Nonmyocyte supporting cells promoted greater ischemia tolerance of cardiac organoids, and e-SiNWs significantly improved electrical pacing capacity. After transplantation into ischemia/reperfusion-injured rat hearts, nanowired cardiac organoids significantly improved contractile development of engrafted hPSC-CMs, induced potent cardiac functional recovery, and reduced maladaptive left ventricular remodeling. Compared to contemporary studies with an identical injury model, greater functional recovery was achieved with a 20-fold lower dose of hPSC-CMs, revealing therapeutic synergy between conductive nanomaterials and human cardiac organoids for efficient heart repair.

Am80, a retinoic acid receptor agonist, activates the cardiomyocyte cell cycle and enhances engraftment in the heart.

Human induced pluripotent stem cell-derived (hiPSC) cardiomyocytes are a promising source for regenerative therapy. To realize this therapy, however, their engraftment potential after their injection into the host heart should be improved. Here, we established an efficient method to analyze the cell cycle activity of hiPSC cardiomyocytes using a fluorescence ubiquitination-based cell cycle indicator (FUCCI) system. Invitro high-throughput screening using FUCCI identified a retinoic acid receptor (RAR) agonist, Am80, as an effective cell cycle activator in hiPSC cardiomyocytes. The transplantation of hiPSC cardiomyocytes treated with Am80 before the injection significantly enhanced the engraftment in damaged mouse heart for 6months. Finally, we revealed that the activation of endogenous Wnt pathways through both RARA and RARB underlies the Am80-mediated cell cycle activation. Collectively, this study highlights an efficient method to activate cell cycle in hiPSC cardiomyocytes by Am80 as a means to increase the graft size after cell transplantation into a damaged heart.

Supramolecular Assemblies of Glycopeptides Enhance Gap Junction Maturation of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes via Inducing Spheroids Formation to Optimize Cardiac Repair.

Stem cell-based therapies have demonstrated significant potential for use in heart regeneration. An effective paradigm for heart repair in rodent and large animal models is the transplantation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Despite this, the functional and phenotypical immaturity of two-dimensional (2D)-cultured hiPSC-CMs, particularly their low electrical integration, poses a caveat for clinical translation. In this study, a supramolecular assembly of a glycopeptide containing a cell adhesion motif-RGD and saccharide-glucose (Bio-Gluc-RGD) was designed to enable the three-dimensional (3D) spheroid formation of hiPSC-CMs, promoting cell-cell and cell-matrix interactions that occur during spontaneous morphogenesis. HiPSC-CMs in spheroids were prone to be phenotypically mature and developed robust gap junctions via activation of the integrin/ILK/p-AKT/Gata4 pathway. Monodispersed hiPSC-CMs encapsulated in the Bio-Gluc-RGD hydrogel were more likely to form aggregates and, therefore, survive in the infarcted myocardium of mice, accompanied by more robust gap junction formation in the transplanted cells, and hiPSC-CMs delivered with the hydrogels also displayed angiogenic effect and anti-apoptosis capacity in the peri-infarct area, enhancing their overall therapeutic efficacy in myocardial infarction. Collectively, our findings illustrate a novel concept for modulating hiPSC-CM maturation by spheroid induction, which has the potential for post-MI heart regeneration. This article is protected by copyright. All rights reserved.

Injectable Decellularized Extracellular Matrix Hydrogel Containing Stromal Cell-Derived Factor 1 Promotes Transplanted Cardiomyocyte Engraftment and Functional Regeneration after Myocardial Infarction

Transplantation of exogenous cardiomyocytes (CMs) is a hopeful method to treat myocardial infarction (MI). However, its clinical application still remains challenging due to low retention and survival rates of the transplanted cells. Herein, a stromal cell-derived factor 1 (SDF-1)-loaded injectable hydrogel based on a decellularized porcine extracellular matrix (dECM) is developed to encapsulate and deliver CMs locally to the infarct area of the heart. The soluble porcine cardiac dECM is composed of similar components such as the human cardiac ECM, which could be self-assembled into a nanofibrous hydrogel at physiological temperature to improve the retention of transplanted CMs. Furthermore, the chemokine SDF-1 could recruit endogenous cells to promote angiogenesis, mitigating the ischemic microenvironment and improving the survival of CMs. The results in vitro show that this composite hydrogel exhibits good biocompatibility, anti-apoptosis property, and chemotactic effects for mesenchymal stromal cells and endothelial cells through SDF-1-CXCR4 axis. Moreover, intramyocardial injection of this composite hydrogel to the infarcted area leads to the promotion of angiogenesis and inhibition of fibrosis, reducing the infarction size and improving the cardiac function. The combination of natural biomaterials, exogenous cells, and bioactive factors shows potential for MI treatment in the clinical application.

Establishment and Industrialization of a New Treatment Method Using Regenerative Cardiomyocyte Transplantation for Refractory Severe Heart Failure - Secondary Publication.

Cardiomyocytes undergo cell division during the fetal period but do not divide after birth; thus, they grow into adult heart cells by enlarging their size. Therefore, heart failure occurs when a certain number of cardiomyocytes are lost owing to myocardial infarction, myocarditis, sarcoidosis, etc. Through scientific efforts, we have developed methods to safely and efficiently generate induced pluripotent stem (iPS) cells from peripheral blood T cells, generate ventricle-specific cardiomyocytes from iPS cells, and remove residual iPS cells and non-cardiomyocytes using the "metabolic selection method" and purify the cardiomyocytes from iPS cell derivatives. We have also developed the technology to mass-produce and efficiently engraft cardiomyocytes by generating cardiomyocyte spheroids and have developed devices suitable for cell transplantation. We have confirmed the safety and efficacy of these techniques by performing preclinical studies (oncogenesis, arrhythmogenicity, etc.) using immunodeficient mice, rats, pigs, and monkeys. Based on these technologies, we have successfully regenerated human ventricular muscle-specific cardiomyocytes with purity greater than 99%. We have also confirmed that the regenerated myocardium transplanted into immunodeficient mice maintained autonomic beating for more than a year without tumor formation. We are planning to conduct clinical trials to transplant iPS cell-derived cardiomyocytes into patients with heart failure associated with ischemic heart disease, which will, in the near future, enable clinical applications using HLA-deficient iPS cells and iPS cells generated from the patient's own lymphocytes to generate regenerative cardiomyocytes without rejection. It would also help establish personalized medicine for heart failure and usher in the long-awaited treatment for intractable severe heart failure using ventricular muscle supplementation.

Intracoronary transplantation of pluripotent stem cell-derived cardiomyocytes: Inefficient procedure for cardiac regeneration

Advances in stem cell biology have facilitated cardiac regeneration, and many animal studies and several initial clinical trials have been conducted using human pluripotent stem cell-derived cardiomyocytes (PSC-CMs). Most preclinical and clinical studies have typically transplanted PSC-CMs via the following two distinct approaches: direct intramyocardial injection or epicardial delivery of engineered heart tissue. Both approaches present common disadvantages, including a mandatory thoracotomy and poor engraftment. Furthermore, a standard transplantation approach has yet to be established. In this study, we tested the feasibility of performing intracoronary administration of PSC-CMs based on a commonly used method of transplanting somatic stem cells. Six male cynomolgus monkeys underwent intracoronary administration of dispersed human PSC-CMs or PSC-CM aggregates, which are called cardiac spheroids, with multiple cell dosages. The recipient animals were sacrificed at 4 weeks post-transplantation for histological analysis. Intracoronary administration of dispersed human PSC-CMs in the cynomolgus monkeys did not lead to coronary embolism or graft survival. Although the transplanted cardiac spheroids became partially engrafted, they also induced scar formation due to cardiac ischemic injury. Cardiac engraftment and scar formation were reasonably consistent with the spheroid size or cell dosage. These findings indicate that intracoronary transplantation of PSC-CMs is an inefficient therapeutic approach.

Space microgravity improves proliferation of human iPSC-derived cardiomyocytes.

SummaryIn microgravity, cells undergo profound changes in their properties. However, how human cardiac progenitors respond to space microgravity is unknown. In this study, we evaluated the effect of space microgravity on differentiation of human induced pluripotent stem cell (hiPSC)-derived cardiac progenitors compared with 1G cultures on the International Space Station (ISS). Cryopreserved 3D cardiac progenitors were cultured for 3 weeks on the ISS. Compared with 1G cultures, the microgravity cultures had 3-fold larger sphere sizes, 20-fold higher counts of nuclei, and increased expression of proliferation markers. Highly enriched cardiomyocytes generated in space microgravity showed improved Ca2+ handling and increased expression of contraction-associated genes. Short-term exposure (3 days) of cardiac progenitors to space microgravity upregulated genes involved in cell proliferation, survival, cardiac differentiation, and contraction, consistent with improved microgravity cultures at the late stage. These results indicate that space microgravity increased proliferation of hiPSC-cardiomyocytes, which had appropriate structure and function.

Purification of human iPSC-derived cells at large scale using microRNA switch and magnetic-activated cell sorting.

SummaryFor regenerative cell therapies using pluripotent stem cell (PSC)-derived cells, large quantities of purified cells are required. Magnetic-activated cell sorting (MACS) is a powerful approach to collect target antigen-positive cells; however, it remains a challenge to purify various cell types efficiently at large scale without using antibodies specific to the desired cell type. Here we develop a technology that combines microRNA (miRNA)-responsive mRNA switch (miR-switch) with MACS (miR-switch-MACS) to purify large amounts of PSC-derived cells rapidly and effectively. We designed miR-switches that detect specific miRNAs expressed in target cells and controlled the translation of a CD4-coding transgene as a selection marker for MACS. For the large-scale purification of induced PSC-derived cardiomyocytes (iPSC-CMs), we transferred miR-208a-CD4 switch-MACS and obtained purified iPSC-CMs efficiently. Moreover, miR-375-CD4 switch-MACS highly purified pancreatic insulin-producing cells and their progenitors expressing Chromogranin A. Overall, the miR-switch-MACS method can efficiently purify target PSC-derived cells for cell replacement therapy.

DeoxyATP producing hiPSC derived cardiomyocyte to restore cardiac function in heart failure

Our group has demonstrated that 2-deoxy-ATP (dATP) improves contractility by activating myosin without affecting the relaxation at various biophysical scales, suggesting a promising sarcomere targeted candidate to mitigate cardiac dysfunction. Over-expression of ribonucleotide reductase (RNR) produces dATP in cardiomyocytes sufficient to increase contractile function. We have shown that dATP spreads between cells via gap junctions and hints that the transplantation of dATP-producing human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) could significantly increase the effectiveness of cardiac cell therapy.

Methods for Transepicardial Cell Transplantation in a Swine Myocardial Infarction Model.

The transplantation of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) has garnered significant attention as a potential means of restoring lost muscle mass and contractile function in injured hearts. Early preclinical work with hPSC-CMs employed rodent models, but the field has recently advanced to transplantation studies in more translationally relevant large animal models including non-human primates and swine. The pig is a particularly attractive model for such studies because the size, structure, and physiology of the porcine heart is very similar to that of humans. The pig model has reasonably high throughput, is readily amenable to clinically available cell delivery methods and imaging modalities and has been used frequently to test the safety and efficacy of new cardiac therapies. Here, we describe methods that were established in our laboratory for the specific purpose of testing hPSC-CM transplantation in a pig model of subacute myocardial infarction, but these same techniques should be broadly applicable to the transepicardial delivery of other biologicals including other candidate cell populations, biomaterials, and/or viral vectors.

Production of functional cardiomyocytes and cardiac tissue from human induced pluripotent stem cells for regenerative therapy

The emergence of human induced pluripotent stem cells (hiPSCs) has revealed the potential for curing end-stage heart failure. Indeed, transplantation of hiPSC-derived cardiomyocytes (hiPSC-CMs) may have applications as a replacement for heart transplantation and conventional regenerative therapies. However, there are several challenges that still must be overcome for clinical applications, including large-scale production of hiPSCs and hiPSC-CMs, elimination of residual hiPSCs, purification of hiPSC-CMs, maturation of hiPSC-CMs, efficient engraftment of transplanted hiPSC-CMs, development of an injection device, and avoidance of post-transplant arrhythmia and immunological rejection. Thus, we developed several technologies based on understanding of the metabolic profiles of hiPSCs and hiPSC derivatives. In this review, we outline how to overcome these hurdles to realize the transplantation of hiPSC-CMs in patients with heart failure and introduce cutting-edge findings and perspectives for future regenerative therapy.