Ischemic heart disease (IHD) is a disease caused by blockage of blood flow to the heart arteries, resulting in reduced blood supply to the heart.[1,2] It is one of the most common causes of death, accounting for more than 9 million mortality per year worldwide. At an early stage of IHD, many patients may be asymptomatic. However, as the atherosclerosis progresses, the patients may not only experience the initial acute myocardial infarction (MI), but also develop progressive heart failure, which is lethal. After ischemic insult such as MI, the myocardium undergoes pathological remodeling, resulting in cardiac muscle cell death, scar formation, cardiac dysfunction, and ultimately leading to heart failure. Cardiac muscle cells, or cardiomyocytes (CMs), have limited regeneration capability and the lost CMs are replaced by a fibrotic scar.
Current treatment approaches include various procedures to restore and improve blood flow, pharmacological treatments that slow or reverse cardiac remodeling, and various strategies to revascularize or regenerate myocardium. Among these methods, stem cell therapy using somatic multipotent stem cells (like bone or adipose derived mesenchymal stem cells, MSCs) and pluripotent stem cells (like embryonic stem cells-ESC and human induced pluripotent stem cells-hiPSCs) represents a promising approach to promote cardiac regeneration and myocardial function recovery.[10,11]
This review aims to provide a state-of-the-art overview of the harnessing of hiPSC derived cells and their derivatives (like secretomes or exosomes) for IHD treatment (Figure 1). First, it will briefly introduce the differentiation of hiPSCs into CMs and vascular cells. Then, it will focus on the recent advances in the injection of hiPSC-CMs and transplantation of hiPSC-CM-based engineered cardiac patch. The delivery or injection of exosomes from hiPSC derived cells will also be presented. Finally, current major technological hurdles and challenges will be discussed, and potential solutions and future directions will be provided.
Human induced pluripotent stem cell differentiation
IPSCs are pluripotent stem cells that are produced from adult somatic cells or blood cells over a genetic reprogramming process back into an embryonic-like pluripotent state.[12,13]Table 1 summarizes some advantages and disadvantages/ concerns as compared to the use of other stem cells (like MSCs and ESCs). hiPSCs have been successfully demonstrated to be capable of differentiating into beating cardiomyocytes through various protocols. The cardiac differentiation of hiPSCs can start from embryoid body (EB) or monolayer culture of hiPSCs.[15,16] Monolayer cultures with Matrigel-coating and/or mouse-embryonic-fibroblast (MEF) feeding layers can result in robust differentiation following pre-differentiation culture, mesoderm induction, early cardiac induction, and maturation process.[14,17] The differentiated hiPSC-CMs exhibit a functionally immature, disorganized, and fetal-like phenotype. Some biochemical, biophysical and engineered approaches, like adding soluble factors excreted by MSCs, applying electrical stimulation, and 3D culture, have been used to improve hiPSC-CM maturation in vitro.
Advantages and disadvantages of hiPSCs
|No ethical concerns (vs. ESCs)||Require reprogramming process and use reprogramming factors (vs. MSCs and ESCs)|
|Unlimited proliferative capacity (vs. MSCs)||Risk of tumorigenesis (both for MSCs and ESCs)|
|Capacity to differentiate into cardiomyocytes and vascular cells (vs. MSCs)||Risk to induce arrhythmias (both for MSCs and ESCs)|
Apart from cardiomyocytes, hiPSCs can also be differentiated into vascular cells, that is, endothelial cells (ECs), smooth muscle cells (SMCs), and pericytes.[22,23] These hiPSC derived vascular cells have also been used, either with hiPSC-CMs or alone, to vascularize the engineered tissue or promote the revascularization of injured myocardium.
Injection of hiPSC derived cells
Currently, in various clinical trials, stem cells have been delivered via various routes (Figure 2), including intravenous injection, intracoronary injection, and intramyocardial injection (transendocardial and transepicardial injection). The intracoronary approach may be more suitable for patients with acute MI, while the intramyocardial injection may be better for patients with late stage of IHD and completely occluded arteries. The choice of delivery method should be highly dependent on the patient’s disease status. At the current stage, most intravenous/ intracoronary injections have been used for MSCs in the clinical or large animal models,[26,27] whereas hiPSC derived cells are mostly delivered through intramyocardial injection (especially transepicardial injection) in the preclinical rodent models or large animal models.
The use of MSCs in the clinical trials and large animal models has much longer history as compared to that of hiPSCs. However, the delivery of MSCs led to only modest benefits for IHD patients, and the results remain controversial without involving a large number of patients. There are many reasons that contribute to the ineffective efficacy. One of the potential reasons and deficiencies is that MSCs have a limited cardiogenic differentiation capacity. Therefore, hiPSCs have obvious advantages as stem cell source to efficiently generate functional cardiomyocytes in vitro and to enable further transplantation. The implementation of iPSC-CMs is still in its infancy stage, so most of the preclinical studies focus on the transepicardial injection in rodent, swine, and non-human primate models. In most rodent models, the proximal left anterior descending (LAD) artery is permanently ligated, and then hiPSC-CMs with or without vascular cells are injected immediately or later (1 or 2 weeks after ligation). The animals are either immunodeficient or immunosuppressed due to the use of human/non-human primate cells. The injection of hiPSC derived cells promoted heart remuscularization and facilitated global functional recovery. However, these results are normally based on short-term experiments (less than 8 weeks after ligation). For large animal models (i.e., swine and non-human primate), due to poor regeneration capacity, temporary occlusion of LAD coronary artery was usually conducted (18–60 min) and then myocardium was reperfused. Positive results about cell survival and engraftment, and improvements in myocardial wall stress, metabolism, and contractile performance were reported after longer-term observation (several weeks to several months). Both hiPSC-CMs and non-human primate iPSC-CMs had comparable therapeutic efficacy and were reported to be superior to injection of fibroblasts and MSCs (in the rodent models). In addition, the injection of hiPSC-CMs together with hiPSC derived vascular cells (i.e., hiPSC-SMCs and hiPSC-ECs) can further reduce cardiomyocyte apoptosis and enhance endogenous cell survival. The hiPSC-CMs can also be combined/ encapsulated with hydrogel delivery system to improve cardiac function post myocardial infarction.
Engineered cardiac patches
Although cell delivery/injection-based strategies have demonstrated some efficacy in attenuating progressive myocardial damage and in some functional recovery, the injected single cells suffer from several major drawbacks like low cell survival and engraftment rate and unknown cell fate. Therefore, another alternative strategy is to develop engineered cardiac patch that can be locally implanted to the surface of infarcted area (Figure 2). Various biomaterials and tissue engineering technologies have been used to generate the engineered cardiac patches. These techniques include molding fibrin/collagen-based hydrogels, electrospun polymeric meshes , stacked cell sheets, and 3D printed/bioprinted constructs. As compared to single hiPSC-CM injection, engineered cardiac patches have several advantages. First, the biomaterials and 3D structures provide biomimetic microenvironments for hiPSC-CMs and increase cell-cell and cell-matrix interaction. Second, many other cell types, like fibroblasts and hiPSC derived vascular cells can be incorporated to improve the contractility and angiogenesis. Third, mechanical and/or electrical stimulation can be applied to facilitate hiPSC-CM maturation. For example, electronic cardiac patch was fabricated by embedding gold electrodes in thin mesh, integrating with electrospun meshes, and further seeding neonatal rat CMs and cardiac fibroblasts. Fourth, the engineered cardiac patches can be fabricated with clinically relevant size and controlled structure (like fiber orientation). Fifth, various therapeutic factors can also be incorporated within cardiac patch to promote vascularization, maturation, or synergistically improve heart functions.
HiPSC derived extracellular vesicles (EVS)
Although there is a consensus that stem cell (especially hiPSC) transplantation exhibits beneficial effects on cardiac protection and function, there are many clinical hurdles, like safety issue and ethic issue, for harnessing hiPSC/ hESC in the clinical applications. In addition, many studies have demonstrated that the positive effects and efficacy of hiPSC-based transplantation are mediated by paracrine actions. Therefore, many researches have focused not only on the hiPSC injection/transplantation, but also on their secretomes, which contain cell-secreted EVs.
The term EV encompasses several subtypes of vesicles that are lipid bilayer-delimited particles and released by cells. The released EVs are highly heterogeneous in size, biogenesis, cargo, and biological function. Based on the size and biogenesis, EVs include exosomes (~30–150 nm), microvesicles (~100 nm–1 mm), and apoptotic bodies (> 1 mm). EVs contain a wide variety of compounds, such as proteins, lipids, messenger RNA (mRNA), and miRNA and can transfer these bioactive molecules between cells and regulate the functions of the recipient cell.[48,49] Therefore, EVs secreted by stem cells have gained enormous interest as therapeutic tools. This is because EVs contain therapeutic cargoes and enable to shuttle these cargos between cells and mediate cell-cell communication. Many studies have shown that cell or plasma derived EVs have cardioprotective effects.[50,51] EVs from different cell types or cells in different states can generate different sets of cargos and bioactive components. For example, exosomes isolated from hiPSC-ECs contained miR-199b-5p and promoted angiogenesis. Exosomes isolated from cardiosphere-derived cells with expression of Lamp2b had cardiomyocyte specific peptide on their surface and increased their uptake by cardiomyocytes. Therefore, the EVs can be engineered by using different cells, co-cultured cells, and biological approaches. Similar to the application of stem cells, EVs can also be injected or combined with cardiac patch for implantation.[54,55]
Challenges and future prospects
Although hiPSC derived cells have gained more and more attention in the last decades and are promising cell sources for IHD treatment, substantial clinical hurdles restrict their further clinical applications in patients. The barriers include low cell engraftment rate, immaturation of hiPSC-CM differentiation, and risk for tumorigenesis and arrhythmogenesis after injection/implantation.
IHD results in a loss of a large number of cardiomyocytes. However, current methods for cell delivery only achieve very poor engraftment (~0.1% to 5% survive and engraft within 24 h). Long-term results from small animal studies demonstrated that the injected cells were present around the injury site for only a short period of time and then died in situ after migrating to distant organs.[25,56] The poor engraftment significantly reduces the efficacy. Although the use of engineered cardiac patch significantly improves the engraftment due to the locally suturing onto the infarct bed surface, the viable and functional cells around the infarction area are not sufficient. Future study will focus more on tracking cell fate after transplantation. This knowledge will help to determine the dose of the cells and optimal delivery mode, and to improve the cell retention and survival.
The differentiated hiPSC-CMs and generated cardiac patches based on hiPSC-CMs have immature properties, disorganized structure, fetal-like phenotypes and display important differences from adult human cardiomyocytes and native adult cardiac tissue. Several review articles have systematically compared their differences.[18,58] Numerous strategies have been developed to improve the maturity of hiPSC-CMs and engineered cardiac tissues. These approaches include varying the culture stiffness, generating biomimetic 3D microenvironment, applying biochemical and electrical stimulation, and combining multiple engineered strategies. Future studies should focus on better understanding of the maturation process, the role of extracellular matrix (ECM) and microenvironment to mimic the physiological environment and promote maturation.
There is also a higher risk of tumorigenesis for the hiPSC-CM transplantation as compared to adult stem cells (i.e. MSCs). By increasing the cell maturation during differentiation and applying rigorous testing to ensure the cell purity, quality, and sterility, the tumorigenesis risk can be reduced. Another potential risk is the development of life-threatening arrhythmias. This may be because of the introduction of conduction blocks and electrical heterogeneities and abnormal automaticity of the transplanted cells. The abnormal repolarization or abnormal calcium cycling of the transplanted cells may increase the risk, whereas better coupling and resynchronization in the infarcted area will reduce the arrhythmia risk. Current pre-clinical animal results using various stem cells and clinical trials using MSCs show limited arrhythmia risk. Longer-term clinical trials for using hiPSC-CMs should be conducted to address this concern.
For future translation to clinical application, compliance with good manufacturing practice (GMP) is mandatory before clinical use. Large scale cell manufacture and differentiation are required to obtain large number of cells within a short period of time. Novel biomaterials and biomaterial systems can serve as artificial ECM to promote cell viability, engraftment, and efficacy. For example, large fibrin hydrogel based cardiac patch with hiPSC derived CMs and vascular cells improved recovery from MI in swine model. For another example, Vandergriff et al. conjugated exosomes with cardiac homing peptide to increase the delivery efficiency. Apart from biomaterials, development of cutting-edge engineering technologies can also advance the future application of hiPSC-CM-based engineered tissues. For example, 3D printing/bioprinting technique enables the precise fabrication of engineered tissues with clinically relevant size, patient-specific features, and functions. 3D printing/bioprinting has been used to fabricate contractile human cardiac ventricle constructs and even whole heart.[69,70]
In summary, the implementation of hiPSC derived cells, the cell-based cardiac patch, and cell-derived exosomes has yielded promising pre-clinical outcomes following IHD. These efforts and results will speed up the development of novel effective regenerative therapies for the clinical setting. However, significant clinical barriers still remain and will not be easily overcome. In order to acknowledge and address the limitations and concerns, the close collaborations between researchers and physicians from multidisciplinary fields are necessary. In addition, due to the complex and sophisticated nature of heart tissue and disease, a combination of multiple therapeutic approaches will be vital to enable successful harnessing of hiPSC-CMs and effectively treating the patients.
Source of Foundation
This work has been supported by Mary & Dick Holland Regenerative Medicine Program start-up grant and University of Nebraska Collaboration Initiative Seed Grant.
Duncker DJ, Koller A, Merkus D, Canty JM Jr. Regulation of coronary blood flow in health and ischemic heart disease. Prog Cardiovasc Dis 2015;57:409–22.
Heusch G, Libby P, Gersh B, Yellon D, Böhm M, Lopaschuk G, et al. Opie. Cardiovascular remodelling in coronary artery disease and heart failure. Lancet 2014;383:1933–43.
Roth GA, Johnson C, Abajobir A, Abd-Allah F, Abera SF, Abyu G, et al. Global, Regional, and National Burden of Cardiovascular Diseases for 10 Causes, 1990 to 2015. J Am Coll Cardiol. 2017;70:1–25.
Malakar AK, Choudhury D, Halder B, Paul P, Uddin A, Chakraborty S. A review on coronary artery disease, its risk factors, and therapeutics. J Cell Physiol 2019;234:16812–23.
Frangogiannis NG.The extracellular matrix in myocardial injury, repair, and remodeling. J Clin Invest 2017;127:1600–12.
Talman V, Ruskoaho H. Cardiac fibrosis in myocardial infarction--from repair and remodeling to regeneration. Cell Tissue Res 2016;365:563–81.
Velazquez EJ, Lee KL, Jones RH, Al-Khalidi HR, Hill JA, Panza JA, et al. Coronary-artery bypass surgery in patients with ischemic cardiomyopathy. N Engl J Med 2016; 374:1511–20.
Fácila Rubio L, Vidal Urrutia V, Morell Cabedo S. New advances in the medical treatment of stable ischemic heart disease, Cardiocore 2018;53:101–5.
Kandaswamy E, Zuo L. Recent advances in treatment of coronary artery disease: Role of science and technology. Int J Mol Sci: 2018;19:E424.
Nguyen PK, Rhee JW, Wu JC. Adult stem cell therapy and heart failure, 2000 to 2016: A systematic review. JAMA Cardiol 2016;1:831–41.
Johnson T, Zhao L, Manuel G, Taylor H, Liu D. Approaches to therapeutic angiogenesis for ischemic heart disease. J Mol Med 2019;97:141–51.
Malik N, Rao MS.. A review of the methods for human iPSC derivation. Methods Mol Biol 2013;997:23–33
Fischer B, Meier A, Dehne A, Salhotra A, Tran TA, Neumann S, et al. A complete workflow for the differentiation and the dissociation of hiPSC-derived cardiospheres. Stem Cell Res 2018;32:65–72.
Smith AS, Macadangdang J, Leung W, Laflamme MA, Kim DH. Human iPSC-derived cardiomyocytes and tissue engineering strategies for disease modeling and drug screening. Biotechnol Adv 2017;35:77–94.
Tan X, Dai Q, Guo T, Xu J, Dai Q. Efficient generation of transgene- and feeder-free induced pluripotent stem cells from human dental mesenchymal stem cells and their chemically defined differentiation into cardiomyocytes. Biochem Biophys Res Commun 2018;495:2490–7.
Dahlmann J, Kensah G, Kempf H, Skvorc D, Gawol A, Elliott DA, et al. The use of agarose microwells for scalable embryoid body formation and cardiac differentiation of human and murine pluripotent stem cells. Biomaterials 2013;34:2463–71.
Peischard S, Piccini I, Strutz-Seebohm N, Greber B, Seebohm G. From iPSC towards cardiac tissue--a road under construction. Pflugers Arch 2017;469:1233–43.
Scuderi GJ, Butcher J. Naturally engineered maturation of cardiomyo-cytes. Front Cell Dev Biol 2017;5:50.
Yoshida S, Miyagawa S, Fukushima S, Kawamura T, Kashiyama N, Ohashi F, et al. Maturation of human induced pluripotent stem cell-derived cardiomyocytes by soluble factors from human mesenchymal stem cells. Mol Ther 2018;26:2681–95.
LaBarge W, Mattappally S, Kannappan R, Fast VG, Pretorius D, Berry JL, et al. Maturation of three-dimensional, hiPSC-derived cardiomyocyte spheroids utilizing cyclic, uniaxial stretch and electrical stimulation. PLoS One 2019;14:e0219442.
Machiraju P, Greenway SC. Current methods for the maturation of induced pluripotent stem cell-derived cardiomyocytes. World J Stem Cells 2019;11:33–43.
Qi D, Wu S, Lin H, Kuss MA, Lei Y, Krasnoslobodtsev A, et al. Establishment of a human iPSC- and nanofiber-based microphysiological blood-brain barrier system. ACS Appl Mater Interfaces 2018;10:21825–35.
Lin H, Du Q, Li Q, Wang O, Wang Z, Liu K, et al. Differentiating human pluripotent stem cells into vascular smooth muscle cells in three dimensional thermoreversible hydrogels. Biomater Sci 2018;7:347–61.
Garbern JC, Lee RT. Cardiac stem cell therapy and the promise of heart regeneration. Cell Stem Cell 2013;12:689–98.
Nguyen PK, Neofytou E, Rhee JW, Wu JC. Potential strategies to address the major clinical barriers facing stem cell regenerative therapy for cardiovascular disease: A review. JAMA Cardiol 2016;1:953–62.
Lunde K, Solheim S, Aakhus S, Arnesen H, Abdelnoor M, Egeland T, et al. Intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction. N Engl J Med 2006;355:1199–209.
Crisostomo V, Baez C, Abad JL, Sanchez B, Alvarez V, Rosado R, et al. Dose-dependent improvement of cardiac function in a swine model of acute myocardial infarction after intracoronary administration of allogeneic heart-derived cells. Stem Cell Res Ther 2019;10:152.
Liu YW, Chen B, Yang X, Fugate JA, Kalucki FA, Futakuchi-Tsuchida A, et al. Human embryonic stem cell-derived cardiomyocytes restore function in infarcted hearts of non-human primates. Nat Biotechnol 2018;36:597–605.
Fisher SA, Zhang H, Doree C, Mathur A, Martin-Rendon E. Stem cell treatment for acute myocardial infarction. Cochrane Database Syst Rev 2015:CD006536.
Chow A, Stuckey DJ, Kidher E, Rocco M, Jabbour RJ, Mansfield CA, et al. Human induced pluripotent stem cell-derived cardiomyocyte encapsulating bioactive hydrogels improve rat heart function post myocardial infarction. Stem Cell Reports 2017;9:1415–22.
Ye L, Chang YH, Xiong Q, Zhang P, Zhang L, Somasundaram P, et al. Cardiac repair in a porcine model of acute myocardial infarction with human induced pluripotent stem cell-derived cardiovascular cells. Cell Stem Cell 2014;15:750–61.
Shiba Y, Gomibuchi T, Seto T, Wada Y, Ichimura H, Tanaka Y, et al. Al-logeneic transplantation of iPS cell-derived cardiomyocytes regenerates primate hearts. Nature 2016;538:388–91.
Citro L, Naidu S, Hassan F, Kuppusamy ML, Kuppusamy P, Angelos MG3, et al. Comparison of human induced pluripotent stem-cell derived cardiomyocytes with human mesenchymal stem cells following acute myocardial infarction. PLoS One 2014;9:e116281.
Merry LL, Bolli R, Canty JM, Du XJ, Frangogiannis NG, Frantz S, et al. Guidelines for experimental models of myocardial ischemia and infarction. Am J Physiol Heart Circ Physiol 2018; 314: H812–38.
Song G, Li X, Shen Y, Qian L, Kong X, Chen M, et al. Transplantation of iPSc restores cardiac function by promoting angiogenesis and ameliorating cardiac remodeling in a post-infarcted swine model. Cell Biochem Biophys 2015;71:1463–73.
Zhao X, Chen H, Xiao D, Yang H, Itzhaki I, Qin X, et al. Comparison of non-human pimate versus human induced pluripotent stem cell-derived cardiomyocytes for treatment of myocardial infarction. Stem Cell Reports 2018;10:422–35.
Zhang J, Zhu W, Radisic M, Vunjak-Novakovic G. Can we engineer a human cardiac patch for therapy? Circ Res 2018;123:244–65.
Kaiser NJ, Kant RJ, Minor AJ, Coulombe KLK. Optimizing blended collagen-fibrin hydrogels for cardiac tissue engineering with human iPSC-derived cardiomyocytes. ACS Biomater Sci Eng 2019;5:887–99.
Li J, Minami I, Shiozaki M, Yu L, Yajima S, Miyagawa S, Shiba Y, Morone N, et al. Human pluripotent stem cell-derived cardiac tissue-like constructs for repairing the infarcted myocardium. Stem Cell Reports 2017;9:1546–559.
Sasaki D, Matsuura K, Seta H, Haraguchi Y, Okano T, Shimizu T. Contractile force measurement of human induced pluripotent stem cell-derived cardiac cell sheet-tissue. PLoS One 2018;13:e0198026.
Ong CS, Fukunishi T, Zhang H, Huang CY, Nashed A, Blazeski A, et al. Biomaterial-free three-dimensional bioprinting of cardiac tissue using human induced pluripotent stem cell derived cardiomyocytes. Sci Rep 2017;7:4566.
Feiner R, Engel L, Fleischer S, Malki M, Gal I, Shapira A, et al. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function. Nat Mater 2016;15:679–85.
Fleischer S, Shapira A, Feiner R, Dvir T. Modular assembly of thick multifunctional cardiac patches. Proc Natl Acad Sci USA 2017;114:1898–903.
Gartz M, Strande JL. Examining the paracrine effects of exosomes in cardiovascular disease and repair. J Am Heart Assoc 2018;7:e007954.
Jung JH, Fu X, Yang PC. Exosomes generated from iPSC-derivatives: New direction for stem cell therapy in human heart diseases. Circ Res 2017;120:407–17.
Maas SLN, Breakefield XO, Weaver AM. Extracellular vesicles: Unique intercellular delivery vehicles. Trends Cell Biol 2017;27:172–88.
Margolis L, Sadovsky Y. The biology of extracellular vesicles: The known unknowns. PLoS Biol 2019;17:e3000363.
Ibrahim A, Marbán E. Exosomes: Fundamental biology and roles in cardiovascular physiology. Annu Rev Physiol 2016;78:67–83.
Zhang Y, Hu YW, Zheng L, Wang Q. Characteristics and roles of exosomes in cardiovascular disease. DNA Cell Biol 2017;36:202–11.
Vicencio JM, Yellon DM, Sivaraman V, Das D, Boi-Doku C, Arjun S, et al. Plasma exosomes protect the myocardium from ischemia-reperfusion injury. J Am Coll Cardiol 2015;65:1525–36.
Chen L, Wang Y, Pan Y, Zhang L, Shen C, Qin G, et al. Cardiac progenitor-derived exosomes protect ischemic myocardium from acute ischemia/ reperfusion injury. Biochem Biophys Res Commun 2013;431:566–71.
Ye M, Ni Q, Qi H, Qian X, Chen J, Guo X, et al. Exosomes derived from human induced pluripotent stem cells-endothelia cells promotes postnatal angiogenesis in mice bearing ischemic limbs. Int J Biol Sci 2019;15:158–68.
Mentkowski KI, Lang JK. Exosomes engineered to express a cardiomyocyte binding peptide demonstrate improved cardiac retention in vivo. Sci Rep 2019;9:10041.
Vandergriff AC, de Andrade JB, Tang J, Hensley MT, Piedrahita JA, Caranasos TG, et al. Intravenous cardiac stem cell-derived exosomes ameliorate cardiac dysfunction in doxorubicin induced dilated cardiomyopathy. Stem Cells Int 2015;2015:960926.
Liu B, Lee BW, Nakanishi K, Villasante A, Williamson R, Metz J, et al. Cardiac recovery via extended cell-free delivery of extracellular vesicles secreted by cardiomyocytes derived from induced pluripotent stem cells. Nat Biomed Eng 2018;2:293–303.
Liu J, Narsinh KH, Lan F, Wang L, Nguyen PK, Hu S, et al. Early stem cell engraftment predicts late cardiac functional recovery preclinical insights from molecular imaging. Circ Cardiovasc Imaging 2012;5:481–90.
Gao L, Gregorich ZR, Zhu W, Mattapally S, Oduk Y, Lou X, et al. Large cardiac muscle patches engineered from human induced-pluripotent stem cell-derived cardiac cells improve recovery from myocardial infarction in swine, Circulation 2018;137:1712–30.
Musunuru K, Sheikh F, Gupta RM, Houser SR, Maher KO, Milan DJ, et al. Induced pluripotent stem cells for cardiovascular disease modeling and precision medicine: A scientific statement from the American Heart Association, Circulation. Circ Genom Precis Med 2018;11:e000043.
Hazeltine LB, Simmons CS, Salick MR, Lian X, Badur MG, Han W, et al. Effects of substrate mechanics on contractility of cardiomyocytes generated from human pluripotent stem cells. Int J Cell Biol 2012;2012:508294.
Nunes SS, Miklas JW, Liu J, Aschar-Sobbi R, Xiao Y, Zhang B, et al. Bio-wire: A platform for maturation of human pluripotent stem cell-derived cardiomyocytes. Nat Methods 2013;10:781–7.
Yang X, Rodriguez M, Pabon L, Fischer KA, Reinecke H, Regnier M, et al. Tri-iodo-l-thyronine promotes the maturation of human cardiomyocytes-derived from induced pluripotent stem cells. J Mol Cell Cardiol 2014;72:296–304.
Chan YC, Ting S, Lee YK, Ng KM, Zhang J, Chen Z, et al. Electrical stimulation promotes maturation of cardiomyocytes derived from human embryonic stem cells. J Cardiovasc Transl Res 2013;6:989–99.
Ronaldson-Bouchard K, Ma SP, Yeager K, Chen T, Song L, Sirabella D, et al. Advanced maturation of human cardiac tissue grown from pluripotent stem cells. Nature 2018;556:239–43.
Lalit PA, Hei DJ, Raval AN, Kamp TJ. Induced pluripotent stem cells for post-myocardial infarction repair: Remarkable opportunities and challenges. Circ Res 2014;114:1328–45.
Baghbaderani BA, Tian X, Neo BH, Burkall A, Dimezzo T, Sierra G, et al. CGMP-manufactured human induced pluripotent stem cells are available for pre-clinical and clinical applications. Stem Cell Reports 2015;5:647–59.
Lin H, Du Q, Li Q, Wang O, Wang Z, Elowsky C, et al. Manufacturing human pluripotent stem cell derived endothelial cells in scalable and cell-friendly microenvironments. Biomater Sci 2018;7:373–88.
Vandergriff A, Huang K, Shen D, Hu S, Hensley MT, Caranasos TG, et al. Targeting regenerative exosomes to myocardial infarction using cardiac homing peptide. Theranostics 2018;8:1869-78.
Duan B. State-of-the-art review of 3D bioprinting for cardiovascular tissue engineering. Ann Biomed Eng 2017;45:195–209.
Lee A, Hudson AR, Shiwarski DJ, Tashman JW, Hinton TJ, Yerneni S, et al. 3D bioprinting of collagen to rebuild components of the human heart. Science 2019;365:482–7.
Noor N, Shapira A, Edri R, Gal I, Wertheim L, et al. 3D printing of personalized thick and perfusable cardiac patches and hearts. Adv Sci (Weinh) 2019;6:1900344.