Therapeutic potential of clinical-grade human induced pluripotent stem cell-derived cardiac tissues

Objectives: To establish a protocol to prepare and transplant clinical-grade human induced pluripotent stem cell (hiPSC)-derived cardiac tissues (HiCTs) and to evaluate the therapeutic potential in an animal myocardial infarction (MI) model. Methods: We simultaneously differentiated clinical-grade hiPSCs into cardiovascular cell lineages with or without the administration of canonical Wnt inhibitors, generated 5- layer cell sheets with insertion of gelatin hydrogel microspheres (GHMs) (HiCTs), and transplanted them onto an athymic rat MI model. Cardiac function was evaluated by echocardiography and cardiac magnetic resonance imaging and compared with that in animals with sham and transplantation of 5-layer cell sheets without GHMs. Graft survival, ventricular remodeling, and neovascularization were evaluated histopathologically. Results: The administration of Wnt inhibitors significantly promoted cardiomyocyte (CM) (P < .0001) and vascular endothelial cell (EC) (P = .006) induction, which resulted in cellular components of 52.0 ± 6.1% CMs and 9.9 ± 3.0% ECs. Functional analyses revealed the significantly lowest left ventricular end-diastolic volume and highest ejection fraction in the HiCT group. Histopathologic evaluation revealed that the HiCT group had a significantly larger median engrafted area (4 weeks, GHM(-) vs HiCT: 0.4 [range, 0.2-0.7] mm² vs 2.2 [range, 1.8-3.1] mm²; P = .005; 12 weeks, 0 [range, 0-0.2] mm² vs 1.9 [range, 0.1-3.2] mm2; P = .026), accompanied by the smallest scar area and highest vascular density at the MI border zone. Conclusions: Transplantation of HiCTs generated from clinical-grade hiPSCs exhibited a prominent therapeutic potential in a rat MI model and may provide a promising therapeutic strategy in cardiac regenerative medicine

ヒトiPS細胞による三次元心臓組織を用いたTorsade de Pointes(トルサード・ド・ポアント) 型不整脈の再現

京都大学0048新制・課程博士博士(医学)甲第20978号医博第4324号新制||医||1026(附属図書館)京都大学大学院医学研究科医学専攻(主査)教授 井上 治久, 教授 木村 剛, 教授 瀬原 淳子学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Modelling Torsade de Pointes arrhythmias in vitro in 3D human iPS cell-engineered heart tissue

ヒトiPS細胞から3次元的な心臓組織を作製し、致死性不整脈の複雑な特徴を培養下に再現することに成功. 京都大学プレスリリース. 2017-10-25.Torsade de Pointes (TdP) is a lethal arrhythmia that is often drug-induced, thus there is an urgent need for development of models to test or predict the drug sensitivity of human cardiac tissue. Here, we present an in vitro TdP model using 3D cardiac tissue sheets (CTSs) that contain a mixture of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and non-myocytes. We simultaneously monitor the extracellular field potential (EFP) and the contractile movement of the CTSs. Upon treatment with IKr channel blockers, CTSs exhibit tachyarrhythmias with characteristics of TdP, including both a typical polymorphic EFP and meandering spiral wave re-entry. The TdP-like waveform is predominantly observed in CTSs with the cell mixture, indicating that cellular heterogeneity and the multi-layered 3D structure are both essential factors for reproducing TdP-like arrhythmias in vitro. This 3D model could provide the mechanistic detail underlying TdP generation and means for drug discovery and safety tests

Specific induction and long-term maintenance of high purity ventricular cardiomyocytes from human induced pluripotent stem cells.

Currently, cardiomyocyte (CM) differentiation methods require a purification step after CM induction to ensure the high purity of the cell population. Here we show an improved human CM differentiation protocol with which high-purity ventricular-type CMs can be obtained and maintained without any CM purification process. We induced and collected a mesodermal cell population (platelet-derived growth factor receptor-α (PDGFRα)-positive cells) that can respond to CM differentiation cues, and then stimulated CM differentiation by means of Wnt inhibition. This method reproducibly generated CMs with purities above 95% in several human pluripotent stem cell lines. Furthermore, these CM populations were maintained in culture at such high purity without any further CM purification step for over 200 days. The majority of these CMs (>95%) exhibited a ventricular-like phenotype with a tendency to structural and electrophysiological maturation, including T-tubule-like structure formation and the ability to respond to QT prolongation drugs. This is a simple and valuable method to stably generate CM populations suitable for cardiac toxicology testing, disease modeling and regenerative medicine

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