Pre-clinical evaluation of the efficacy and safety of human induced pluripotent stem cell-derived cardiomyocyte patch

BACKGROUND

Cell- or tissue-based regenerative therapy is an attractive approach to treat heart failure. A tissue patch that can safely and effectively repair damaged heart muscle would greatly improve outcomes for patients with heart failure. In this study, we conducted a preclinical proof-of-concept analysis of the efficacy and safety of clinical-grade human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) patches.

METHODS

A clinical-grade hiPSC line was established using peripheral blood mononuclear cells from a healthy volunteer that was homozygous for human leukocyte antigens. The hiPSCs were differentiated into cardiomyocytes. The obtained hiPSC-CMs were cultured on temperature-responsive culture dishes for patch fabrication. The cellular characteristics, safety, and efficacy of hiPSCs, hiPSC-CMs, and hiPSC-CM patches were analyzed.

RESULTS

The hiPSC-CMs expressed cardiomyocyte-specific genes and proteins, and electrophysiological analyses revealed that hiPSC-CMs exhibit similar properties to human primary myocardial cells. In vitro and in vivo safety studies indicated that tumorigenic cells were absent. Moreover, whole-genome and exome sequencing revealed no genomic mutations. General toxicity tests also showed no adverse events posttransplantation. A porcine model of myocardial infarction demonstrated significantly improved cardiac function and angiogenesis in response to cytokine secretion from hiPSC-CM patches. No lethal arrhythmias were observed.

CONCLUSIONS

hiPSC-CM patches are promising for future translational research and may have clinical application potential for the treatment of heart failure.

Human induced pluripotent stem cell-derived closed-loop cardiac tissue for drug assessment

Human iPSC-derived cardiomyocytes (hiPSC-CMs) exhibit functional immaturity, potentially impacting their suitability for assessing drug proarrhythmic potential. We previously devised a traveling wave (TW) system to promote maturation in 3D cardiac tissue. To align with current drug assessment paradigms (CiPA and JiCSA), necessitating a 2D monolayer cardiac tissue, we integrated the TW system with a multi-electrode array. This gave rise to a hiPSC-derived closed-loop cardiac tissue (iCT), enabling spontaneous TW initiation and swift pacing of cardiomyocytes from various cell lines. The TW-paced cardiomyocytes demonstrated heightened sarcomeric and functional maturation, exhibiting enhanced response to isoproterenol. Moreover, these cells showcased diminished sensitivity to verapamil and maintained low arrhythmia rates with ranolazine-two drugs associated with a low risk of torsades de pointes (TdP). Notably, the TW group displayed increased arrhythmia rates with high and intermediate risk TdP drugs (quinidine and pimozide), underscoring the potential utility of this system in drug assessment applications.

Gene correction and overexpression of TNNI3 improve impaired relaxation in engineered heart tissue model of pediatric restrictive cardiomyopathy

Research on cardiomyopathy models using engineered heart tissue (EHT) created from disease-specific induced pluripotent stem cells (iPSCs) is advancing rapidly. However, the study of restrictive cardiomyopathy (RCM), a rare and intractable cardiomyopathy, remains at the experimental stage because there is currently no established method to replicate the hallmark phenotype of RCM, particularly diastolic dysfunction, in vitro. In this study, we generated iPSCs from a patient with early childhood-onset RCM harboring the TNNI3 R170W mutation (R170W-iPSCs). The properties of R170W-iPSC-derived cardiomyocytes (CMs) and EHTs were evaluated and compared with an isogenic iPSC line in which the mutation was corrected. Our results indicated altered calcium kinetics in R170W-iPSC-CMs, including prolonged tau, and an increased ratio of relaxation force to contractile force in R170W-EHTs. These properties were reversed in the isogenic line, suggesting that our model recapitulates impaired relaxation of RCM, i.e., diastolic dysfunction in clinical practice. Furthermore, overexpression of wild-type TNNI3 in R170W-iPSC-CMs and -EHTs effectively rescued impaired relaxation. These results highlight the potential efficacy of EHT, a modality that can accurately recapitulate diastolic dysfunction in vitro, to elucidate the pathophysiology of RCM, as well as the possible benefits of gene therapies for patients with RCM.

Pleiotropic effects of extracellular vesicles from induced pluripotent stem cell-derived cardiomyocytes on ischemic cardiomyopathy: A preclinical study

BACKGROUND

Stem cell-secreted extracellular vesicles (EVs) play essential roles in intercellular communication and restore cardiac function in animal models of ischemic heart disease. However, few studies have used EVs derived from clinical-grade stem cells and their derivatives with stable quality. Moreover, there is little information on the mechanism and time course of the multifactorial effect of EV therapy from the acute to the chronic phase, the affected cells, and whether the effects are direct or indirect.

METHODS

Induced pluripotent stem cell-derived cardiomyocytes (iPSCM) were produced using a clinical-grade differentiation induction system. EVs were isolated from the conditioned medium by ultracentrifugation and characterized in silico, in vitro, and in vivo. A rat model of myocardial infarction was established by left anterior descending artery ligation and treated with iPSCM-derived EVs.

RESULTS

iPSCM-derived EVs contained microRNAs and proteins associated with angiogenesis, antifibrosis, promotion of M2 macrophage polarization, cell proliferation, and antiapoptosis. iPSCM-derived EV treatment improved left ventricular function and reduced mortality in the rat model by improving vascularization and suppressing fibrosis and chronic inflammation in the heart. EVs were uptaken by cardiomyocytes, endothelial cells, fibroblasts, and macrophages in the cardiac tissues. The pleiotropic effects occurred due to the direct effects of microRNAs and proteins encapsulated in EVs and indirect paracrine effects on M2 macrophages.

CONCLUSIONS

Clinical-grade iPSCM-derived EVs improve cardiac function by regulating various genes and pathways in various cell types and may have clinical potential for treating ischemic heart disease.

An extremely energetic cosmic ray observed by a surface detector array

Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest-energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection requires instruments with large collecting areas. In this work, we report the detection of an extremely energetic particle recorded by the surface detector array of the Telescope Array experiment. We calculate the particle's energy as [Formula: see text] (~40 joules). Its arrival direction points back to a void in the large-scale structure of the Universe. Possible explanations include a large deflection by the foreground magnetic field, an unidentified source in the local extragalactic neighborhood, or an incomplete knowledge of particle physics.

Safety confirmation of induced pluripotent stem cell-derived cardiomyocyte patch transplantation for ischemic cardiomyopathy: first three case reports

Introduction

With the expected increase in patients with heart failure and ischemic 15 cardiomyopathy, the development of myocardial regenerative medicine using cell transplantation as a novel treatment method is progressing. This first-in-human clinical trial aimed to confirm the safety of cardiomyocyte patch transplantation derived from allogeneic induced pluripotent stem (iPS) cells based on the results of several preclinical studies.

Study design

The inclusion criteria were left ventricular ejection fraction of 35% or less; heart failure symptoms of New York Heart Association class III or higher despite existing therapies such as revascularization; and a 1-year observation period that included a 3-month immunosuppressive drug administration period after transplantation of iPS cell-derived cardiomyocyte patches to evaluate adverse events, cardiac function, myocardial blood flow, heart failure symptoms, and immune response.

Results

In the first three cases of this trial, no transplanted cell-related adverse events were observed during the 1-year observation period, and improvement in heart failure symptoms was observed. In addition, improvements in left ventricular contractility and myocardial blood flow were observed in two of the three patients. Regarding immune response, an increase in transplant cell-specific antibody titer was observed in all three patients after immunosuppressive drug administration. In one patient with poor improvement in cardiac function and myocardial blood flow, an increase in antibody titer against HLA-DQ was observed even before cell transplantation.

Conclusions

Our case findings demonstrate that the transplantation of iPS cell-derived cardiomyocyte patches for ischemic cardiomyopathy can be safely performed; however, further investigation of the therapeutic effect and its relationship with an immune response is needed by accumulating the number of patients through continued clinical trials.

Error analysis of Raven's Coloured Progressive Matrices in children and adolescents with cerebral palsy

BACKGROUND

Analysis of the errors in the Raven's Coloured Progressive Matrices (RCPM) has been previously performed for children with intellectual disabilities but has not been investigated for those with cerebral palsy (CP). This study aimed to investigate whether the types and positions of errors made by individuals with CP differed from those made by typically developing (TD) controls.

METHODS

Forty-five participants with CP aged 4-18 years and 30 TD children aged 3-9 years underwent RCPM testing. We first compared the RCPM performance and error characteristics between the groups and then examined the association between RCPM and the severity of CP and receptive vocabulary in the CP group.

RESULTS

The results showed that while mean total scores in the two groups were comparable, the types and positions of errors made by individuals with CP differed from those of TD controls. The development of non-verbal intelligence in children with CP increased with age; when controlling for age, non-verbal intelligence was significantly correlated with all three functional levels of CP severity and receptive vocabulary.

CONCLUSIONS

This study provides valuable insights into the problem-solving strategies employed by children with CP.

Estimation of crossbridge-state during cardiomyocyte beating using second harmonic generation

Estimation of dynamic change of crossbridge formation in living cardiomyocytes is expected to provide crucial information for elucidating cardiomyopathy mechanisms, efficacy of an intervention, and others. Here, we established an assay system to dynamically measure second harmonic generation (SHG) anisotropy derived from myosin filaments depended on their crossbridge status in pulsating cardiomyocytes. Experiments utilizing an inheritable mutation that induces excessive myosin-actin interactions revealed that the correlation between sarcomere length and SHG anisotropy represents crossbridge formation ratio during pulsation. Furthermore, the present method found that ultraviolet irradiation induced an increased population of attached crossbridges that lost the force-generating ability upon myocardial differentiation. Taking an advantage of infrared two-photon excitation in SHG microscopy, myocardial dysfunction could be intravitally evaluated in a Drosophila disease model. Thus, we successfully demonstrated the applicability and effectiveness of the present method to evaluate the actomyosin activity of a drug or genetic defect on cardiomyocytes. Because genomic inspection alone may not catch the risk of cardiomyopathy in some cases, our study demonstrated herein would be of help in the risk assessment of future heart failure.

Establishment of a protocol to administer immunosuppressive drugs for iPS cell-derived cardiomyocyte patch transplantation in a rat myocardial infarction model

Transplantation of human allogeneic induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is a new, promising treatment for severe heart failure. However, immunorejection is a significant concern in allogeneic hiPSC-CM transplantation, requiring the administration of several immunosuppressive agents. An appropriate protocol for the administration of immunosuppressants may substantially affect the efficacy of hiPSC-CM transplantation in case of heart failure owing to allogeneic transplantation. In this study, we investigated the effect of immunosuppressant administration duration on the efficacy and safety of allogenic hiPSC-CM patch transplantation. We used a rat model of myocardial infarction to evaluate cardiac function using echocardiography six months after the transplantation of hiPSC-CM patches with immunosuppressant administration for either two or four months and compared them to control rats (sham operation, no immunosuppressant administration). Histological analysis performed at 6 months after hiPSC-CM patch transplantation revealed significant improvement in cardiac function in immunosuppressant-treated rats compared with those in the control group. Moreover, fibrosis and cardiomyocyte size was significantly reduced and the number of structurally mature blood vessels was significantly increased in the immunosuppressant-treated rats compared to control rats. However, there were no significant differences between the two immunosuppressant-treated groups. Our results show that prolonged administration of immunosuppressive agents did not enhance the effectiveness of hiPSC-CM patch transplantation, and therefore, highlight the importance of an appropriate immunological regimen for the clinical application of such transplantation.

Case report: Transplantation of human induced pluripotent stem cell-derived cardiomyocyte patches for ischemic cardiomyopathy

Despite major therapeutic advances, heart failure, as a non-communicable disease, remains a life-threatening disorder, with 26 million patients worldwide, causing more deaths than cancer. Therefore, novel strategies for the treatment of heart failure continue to be an important clinical need. Based on preclinical studies, allogenic human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) patches have been proposed as a potential therapeutic candidate for heart failure. We report the implantation of allogeneic hiPSC-CM patches in a patient with ischemic cardiomyopathy (ClinicalTrials.gov, #jRCT2053190081). The patches were produced under clinical-grade conditions and displayed cardiogenic phenotypes and safety in vivo (severe immunodeficient mice) without any genetic mutations in cancer-related genes. The patches were then implanted via thoracotomy into the left ventricle epicardium of the patient under immunosuppressive agents. Positron emission tomography and computed tomography confirmed the potential efficacy and did not detect tumorigenesis in either the heart or other organs. The clinical symptoms improved 6 months after surgery, without any major adverse events, suggesting that the patches were well-tolerated. Furthermore, changes in the wall motion in the transplanted site were recovered, suggesting a favorable prognosis and the potential tolerance to exercise. This study is the first report of a successful transplant of hiPSC-CMs for severe ischemic cardiomyopathy.

Human-Induced Pluripotent Stem Cell–Derived Cardiomyocyte Model for TNNT2 Δ160E-Induced Cardiomyopathy

The Δ160E mutation in TNNT2, which encodes troponin T, is a rare pathogenic variant identified in patients with hypertrophic cardiomyopathy and is associated with poor prognosis. Thus, a convenient human model recapitulating the pathological phenotype caused by TNNT2 Δ160E is required for therapeutic development.

Modeling reduced contractility and impaired desmosome assembly due to plakophilin-2 deficiency using isogenic iPS cell-derived cardiomyocytes

Loss-of-function mutations in PKP2, which encodes plakophilin-2, cause arrhythmogenic cardiomyopathy (AC). Restoration of deficient molecules can serve as upstream therapy, thereby requiring a human model that recapitulates disease pathology and provides distinct readouts in phenotypic analysis for proof of concept for gene replacement therapy. Here, we generated isogenic induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) with precisely adjusted expression of plakophilin-2 from a patient with AC carrying a heterozygous frameshift PKP2 mutation. After monolayer differentiation, plakophilin-2 deficiency led to reduced contractility, disrupted intercalated disc structures, and impaired desmosome assembly in iPSC-CMs. Allele-specific fluorescent labeling of endogenous DSG2 encoding desmoglein-2 in the generated isogenic lines enabled real-time desmosome-imaging under an adjusted dose of plakophilin-2. Adeno-associated virus-mediated gene replacement of PKP2 recovered contractility and restored desmosome assembly, which was sequentially captured by desmosome-imaging in plakophilin-2-deficient iPSC-CMs. Our isogenic set of iPSC-CMs recapitulates AC pathology and provides a rapid and convenient cellular platform for therapeutic development.

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Generation of isogenic iPSC-CMs with a precise dose of plakophilin-2

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Modeling reduced contractility and impaired desmosome assembly using iPSC-CMs

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Generation of isogenic iPSC-CMs for desmosome-imaging

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Proof of concept of PKP2 replacement using isogenic plakophilin-2-deficient iPSC-CMs

Genetic diversity of Lactobacillus delbrueckii isolated from raw milk in Hokkaido, Japan

Lactic acid bacteria (LAB) play important roles in acid production and flavor formation in fermented dairy products. Lactic acid bacteria strains with distinct characteristics confer unique features to products. Diverse LAB have been identified in raw milk and traditional fermented milk prepared from raw milk. However, little is known about LAB in raw milk in Japan. To preserve diverse LAB as potential starters or probiotics for future use, we have isolated and identified various kinds of LAB from raw milk produced in Japan. In this study, we focused on Lactobacillus delbrueckii, one of the most important species in the dairy industry. We identified L. delbrueckii subspecies isolated from raw milk in Hokkaido, Japan, by analyzing intraspecific diversity using 4 distinct methods, hsp60 cluster analysis, multilocus sequence analysis, core-genome analysis, and whole-genome analysis based on average nucleotide identity. The subspecies distribution and a new dominant subset of L. delbrueckii from raw milk in Japan were revealed. The discovery of new strains with different genotypes is important for understanding the geographic distribution and characteristics of the bacteria and further their use as a microbial resource with the potential to express unconventional flavors and functionalities. The strains identified in this study may have practical applications in the development of fermented dairy products.

Cardiotoxicity assessment using 3D vascularized cardiac tissue consisting of human iPSC-derived cardiomyocytes and fibroblasts

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for cardiac safety assessment but have limitations for the evaluation of drug-induced contractility. Three-dimensional (3D) cardiac tissues are similar to native tissue and valuable for the assessment of contractility. However, a longer time and specialized equipment are required to generate 3D tissues. We previously developed a simple method to generate 3D tissue in a short period by coating the cell surfaces with extracellular matrix proteins. We hypothesized that this 3D cardiac tissue could be used for simultaneous evaluation of drug-induced repolarization and contractility. In the present work, we examined the effects of several compounds with different mechanisms of action by cell motion imaging. Consequently, human ether-a-go-go-related gene (HERG) channel blockers with high arrhythmogenic risk caused prolongation of contraction-relaxation duration and arrhythmia-like waveforms. Positive inotropic drugs, which increase intracellular Ca²⁺ levels or myocardial Ca²⁺ sensitivity, caused an increase in maximum contraction speed (MCS) or average deformation distance (ADD) (ouabain, 138% for MCS at 300 nM; pimobendane, 132% for ADD at 3 μM). For negative inotropic drugs, verapamil reduced both MCS and ADD (61% at 100 nM). Thus, this 3D cardiac tissue detected the expected effects of various cardiovascular drugs, suggesting its usefulness for cardiotoxicity evaluation.

Clinical Outcomes of Autologous Stem Cell-Patch Implantation for Patients With Heart Failure With Nonischemic Dilated Cardiomyopathy

Background

Clinical effectiveness of autologous skeletal cell‐patch implantation for nonischemic dilated cardiomyopathy has not been clearly elucidated in clinical settings. This clinical study aimed to determine the feasibility, safety, therapeutic efficacy, and the predictor of responders of this treatment in patients with nonischemic dilated cardiomyopathy.

Methods and Results

Twenty‐four nonischemic dilated cardiomyopathy patients with left ventricular ejection fraction <35% on optimal medical therapy were enrolled. Autologous cell patches were implanted over the surface of the left ventricle through left minithoracotomy without procedure‐related complications and lethal arrhythmia. We identified 13 responders and 11 nonresponders using the combined indicator of a major cardiac adverse event and incidence of heart failure event. In the responders, symptoms, exercise capacity, and cardiac performance were improved postoperatively (New York Heart Association class II 7 [54%] and III 6 [46%] to New York Heart Association class II 12 [92%] and I 1 [8%], P<0.05, 6‐minute walk test; 471 m [370–541 m] to 525 m [425–555 m], P<0.05, left ventricular stroke work index; 31.1 g·m²·beat [22.7–35.5 g·m²·beat] to 32.8 g·m²·beat [28–38.5 g·m²·beat], P=0.21). However, such improvement was not observed in the nonresponders. In responders, the actuarial survival rate was 90.9±8.7% at 5 years, which was superior to the estimated survival rate of 70.9±5.4% using the Seattle Heart Failure Model. However, they were similar in nonresponders (47.7±21.6% and 56.3±8.1%, respectively). Multivariate regression model with B‐type natriuretic peptide, pulmonary capillary wedge pressure, and expression of histone H3K4me3 (H3 lysine 4 trimethylation) strongly predicted the responder of this treatment (B‐type natriuretic peptide: odds ratio [OR], 0.96; pulmonary capillary wedge pressure: ​OR, 0.58; H3K4me3: OR, 1.35, receiver operating characteristic–area under the curve, 0.96, P<0.001).

Conclusions

This clinical trial demonstrated that autologous skeletal stem cell–patch implantation might promise functional recovery and good clinical outcome in selected patients with nonischemic dilated cardiomyopathy, in addition to safety and feasibility.

Registration

URL: http://www.umin.ac.jp/english/. Unique identifiers: UMIN000003273, UMIN0000012906 and UMIN000015892.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.