Regeneration of Nonhuman Primate Hearts With Human Induced Pluripotent Stem Cell-Derived Cardiac Spheroids.

BACKGROUND: The clinical application of human induced pluripotent stem cell-derived cardiomyocytes (CMs) for cardiac repair commenced with the epicardial delivery of engineered cardiac tissue; however, the feasibility of the direct delivery of human induced pluripotent stem cell-derived CMs into the cardiac muscle layer, which has reportedly induced electrical integration, is unclear because of concerns about poor engraftment of CMs and posttransplant arrhythmias. Thus, in this study, we prepared purified human induced pluripotent stem cell-derived cardiac spheroids (hiPSC-CSs) and investigated whether their direct injection could regenerate infarcted nonhuman primate hearts. METHODS: We performed 2 separate experiments to explore the appropriate number of human induced pluripotent stem cell-derived CMs. In the first experiment, 10 cynomolgus monkeys were subjected to myocardial infarction 2 weeks before transplantation and were designated as recipients of hiPSC-CSs containing 2×107 CMs or the vehicle. The animals were euthanized 12 weeks after transplantation for histological analysis, and cardiac function and arrhythmia were monitored during the observational period. In the second study, we repeated the equivalent transplantation study using more CMs (6×107 CMs). RESULTS: Recipients of hiPSC-CSs containing 2×107 CMs showed limited CM grafts and transient increases in fractional shortening compared with those of the vehicle (fractional shortening at 4 weeks after transplantation [mean ± SD]: 26.2±2.1%; 19.3±1.8%; P<0.05), with a low incidence of posttransplant arrhythmia. Transplantation of increased dose of CMs resulted in significantly greater engraftment and long-term contractile benefits (fractional shortening at 12 weeks after transplantation: 22.5±1.0%; 16.6±1.1%; P<0.01, left ventricular ejection fraction at 12 weeks after transplantation: 49.0±1.4%; 36.3±2.9%; P<0.01). The incidence of posttransplant arrhythmia slightly increased in recipients of hiPSC-CSs containing 6×107 CMs. CONCLUSIONS: We demonstrated that direct injection of hiPSC-CSs restores the contractile functions of injured primate hearts with an acceptable risk of posttransplant arrhythmia. Although the mechanism for the functional benefits is not fully elucidated, these findings provide a strong rationale for conducting clinical trials using the equivalent CM products.

Pluripotent stem cell-based cardiac regenerative therapy for heart failure.

Cardiac regenerative therapy using human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is expected to become an alternative to heart transplantation for severe heart failure. It is now possible to produce large numbers of human pluripotent stem cells (hPSCs) and eliminate non-cardiomyocytes, including residual undifferentiated hPSCs, which can cause teratoma formation after transplantation. There are two main strategies for transplanting hPSC-CMs: injection of hPSC-CMs into the myocardium from the epicardial side, and implantation of hPSC-CM patches or engineered heart tissues onto the epicardium. Transplantation of hPSC-CMs into the myocardium of large animals in a myocardial infarction model improved cardiac function. The engrafted hPSC-CMs matured, and microvessels derived from the host entered the graft abundantly. Furthermore, as less invasive methods using catheters, injection into the coronary artery and injection into the myocardium from the endocardium side have recently been investigated. Since transplantation of hPSC-CMs alone has a low engraftment rate, various methods such as transplantation with the extracellular matrix or non-cardiomyocytes and aggregation of hPSC-CMs have been developed. Post-transplant arrhythmias, imaging of engrafted hPSC-CMs, and immune rejection are the remaining major issues, and research is being conducted to address them. The clinical application of cardiac regenerative therapy using hPSC-CMs has just begun and is expected to spread widely if its safety and efficacy are proven in the near future.

Cardiac Regenerative Therapy Using Human Pluripotent Stem Cells for Heart Failure: A State-of-the-Art Review.

Heart transplantation (HT) is the only definitive treatment available for patients with end-stage heart failure who are refractory to medical and device therapies. However, HT as a therapeutic option, is limited by a significant shortage of donors. To overcome this shortage, regenerative medicine using human pluripotent stem cells (hPSCs), such as human embryonic stem cells and human-induced pluripotent stem cells (hiPSCs), has been considered an alternative to HT. Several issues, including the methods of large-scale culture and production of hPSCs and cardiomyocytes, the prevention of tumorigenesis secondary to contamination of undifferentiated stem cells and non-cardiomyocytes, and the establishment of an effective transplantation strategy in large-animal models, need to be addressed to fulfill this unmet need. Although post-transplantation arrhythmia and immune rejection remain problems, the ongoing rapid technological advances in hPSC research have been directed toward the clinical application of this technology. Cell therapy using hPSC-derived cardiomyocytes is expected to serve as an integral component of realistic medicine in the near future and is being potentially viewed as a treatment that would revolutionize the management of patients with severe heart failure.

Perspectives of hospitalized heart failure patients: preferred and perceived participation roles in treatment decisions.

Shared decision-making (SDM) is a pivotal process in seeking optimal individual treatment and incorporating clinical evidence and patients' autonomous preferences. However, patients' actual attitudes toward participation in decision-making for state-of-the-art heart failure (HF) treatment remain unclear. We conducted a questionnaire-based survey distributed by nurses and physicians specializing in HF care to assess patients' preferred and perceived participation roles in treatment decision-making during the index hospitalization, rated on five scales (from extremely passive to purely autonomous attitudes). Simultaneously, we investigated the important factors underlying treatment decision-making from the perspective of hospitalized HF patients. Of the 202 patients who were approached by our multidisciplinary HF team between 2017 and 2020, 166 (82.2%) completed the survey. Logistic regression analyses were conducted to identify the clinical determinants of patients who reported that they left all decisions to physicians (i.e., extremely passive attitude). Of the 166 participants (male 67.5%, median age 73 years), 32.5% preferred an extremely passive attitude, while 61.4% reported that they actually chose an extremely passive attitude. A sole determinant of choosing an extremely passive decision-making role was lower educational status (odds ratio: 2.11, 95% confidence interval 1.11-4.00). The most important factor underlying the decision-making was "Physician recommendation" (89.2%). Notably, less than 50% considered "In alignment with my values and preferences" as an important factor underlying treatment decision-making. The majority of HF patients reported that they chose an extremely passive approach, and patients prioritized physician recommendation over their own values and preferences.

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.

Concise Review: Genetic and Epigenetic Regulation of Cardiac Differentiation from Human Pluripotent Stem Cells.

Human pluripotent stem cells (hPSCs), including both embryonic stem cells and induced pluripotent stem cells, are the ideal cell sources for disease modeling, drug discovery, and regenerative medicine. In particular, regenerative therapy with hPSC-derived cardiomyocytes (CMs) is an unmet medical need for the treatment of severe heart failure. Cardiac differentiation protocols from hPSCs are made on the basis of cardiac development in vivo. However, current protocols have yet to yield 100% pure CMs, and their maturity is low. Cardiac development is regulated by the cardiac gene network, including transcription factors (TFs). According to our current understanding of cardiac development, cardiac TFs are sequentially expressed during cardiac commitment in hPSCs. Expression levels of each gene are strictly regulated by epigenetic modifications. DNA methylation, histone modification, and noncoding RNAs significantly influence cardiac differentiation. These complex circuits of genetic and epigenetic factors dynamically affect protein expression and metabolic changes in cardiac differentiation and maturation. Here, we review cardiac differentiation protocols and their molecular machinery, closing with a discussion of the future challenges for producing hPSC-derived CMs. Stem Cells 2019;37:992-1002.

Selective elimination of undifferentiated human pluripotent stem cells using pluripotent state-specific immunogenic antigen Glypican-3.

Immunogenicity of immature pluripotent stem cells is a topic of intense debate. Immunogenic antigens, which are specific in pluripotent states, have not been described previously. In this study, we identified glypican-3 (GPC3), a known carcinoembryonic antigen, as a pluripotent state-specific immunogenic antigen. Additionally, we validated the applicability of human leukocyte antigen (HLA)-class I-restricted GPC3-reactive cytotoxic T lymphocytes (CTLs) in the removal of undifferentiated pluripotent stem cells (PSCs) from human induced pluripotent stem cell (hiPSC)-derivatives. HiPSCs uniquely express GPC3 in pluripotent states and were rejected by GPC3-reactive CTLs, which were sensitized with HLA-class I-restricted GPC3 peptides. Furthermore, GPC3-reactive CTLs selectively removed undifferentiated PSCs from hiPSC-derivatives in vitro and inhibited tumor formation in vivo. Our results demonstrate that GPC3 works as a pluripotent state-specific immunogenic antigen in hiPSCs and is applicable to regenerative medicine as a method of removing undifferentiated PSCs, which are the main cause of tumor formation.

Comparison among various physiology and angiography-guided strategies for deferring percutaneous coronary intervention: A network meta-analysis.

BACKGROUND/PURPOSE: It is unclear whether coronary physiology or coronary angiography (CA)-guided strategy is the more preferable approach for deferring percutaneous coronary intervention (PCI). We sought to evaluate the clinical efficacy of various PCI strategies through a network meta-analysis of randomized controlled trials (RCTs). METHODS/MATERIALS: We searched multiple databases for RCTs investigating the impact of the following strategies for the purpose of determining whether or not to defer PCI: fractional flow reserve, instantaneous wave-free ratio, quantitative flow ratio (QFR), and CA. We conducted a network meta-analysis for trial-defined major adverse cardiovascular events (MACE), all-cause death, cardiovascular death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis. We performed a subgroup analysis for those with acute coronary syndrome (ACS). RESULTS: Our search identified 12 eligible RCTs including a total of 13,177 patients. QFR-guided PCI was associated with reduced MACE, MI, and TLR compared with CA-guided PCI (relative risk (RR) 0.68; 95 % confidence interval (CI] [0.49 to 0.94], RR 0.58; 95 % CI [0.36 to 0.96], and RR 0.58; 95 % CI [0.38 to 0.91], respectively). There were no significant differences in any pairs for all-cause death, cardiovascular death, or stent thrombosis. QFR was ranked the best in most outcomes. In the subgroup analysis of the ACS cohort, there were no significant differences in MACE between any comparisons. CONCLUSIONS: QFR was associated with reduced MACE, MI, and TLR compared with CA, and ranked the best in most outcomes. However, this was not applied in the ACS cohort.

Coronary Artery Bypass Grafting for a Young Female Patient With Chronic Active Epstein-Barr Virus Infection.

A 24-year-old woman with chronic active Epstein-Barr virus (CAEBV) infection successfully underwent coronary artery bypass grafting for triple coronary arteries with chronic total occlusion and aneurysms. This case underscores the importance of accurate assessment and treatment of coronary artery lesions in patients with CAEBV infection.

Left circumflex coronary artery is protected against no-reflow phenomenon following percutaneous coronary intervention for coronary artery disease.

Despite the positive impact of percutaneous coronary intervention (PCI) on reducing mortality, a small percentage of patients experience poor myocardial reperfusion following PCI. However, factors associated with no-reflow remain unclear. We investigated clinical factors associated with no-reflow following PCI for coronary artery disease (CAD). We retrospectively analyzed 1622 consecutive CAD patients who underwent PCI over a 5-year period at our institution. Patients were divided into two groups according to the presence (n = 31) or absence (n = 1591) of no-reflow, defined as Thrombolysis in Myocardial Infarction flow grade <3 after PCI. No significant differences in patient characteristics or PCI strategy were seen between the no-reflow and normal flow groups. The incidence of no-reflow was significantly lower in the left circumflex artery (LCx) than in the left anterior descending artery (LAD) (P = 0.0015), with no differences in characteristics or PCI strategy between these two target vessels. Multivariate analysis revealed that involvement of the LCx was an independent protective factor against no-reflow (odds ratio 0.14, 95 % confidence interval 0.02-0.98, P = 0.044). In conclusion, LCx as the target vessel was protective against no-reflow compared with LAD following PCI for CAD. Our results suggest that embolic protection devices may be unnecessary in CAD patients with involvement of LCx.

Unlocking the Pragmatic Potential of Regenerative Therapies in Heart Failure with Next-Generation Treatments.

Patients with chronic heart failure (HF) have a poor prognosis due to irreversible impairment of left ventricular function, with 5-year survival rates <60%. Despite advances in conventional medicines for HF, prognosis remains poor, and there is a need to improve treatment further. Cell-based therapies to restore the myocardium offer a pragmatic approach that provides hope for the treatment of HF. Although first-generation cell-based therapies using multipotent cells (bone marrow-derived mononuclear cells, mesenchymal stem cells, adipose-derived regenerative cells, and c-kit-positive cardiac cells) demonstrated safety in preclinical models of HF, poor engraftment rates, and a limited ability to form mature cardiomyocytes (CMs) and to couple electrically with existing CMs, meant that improvements in cardiac function in double-blind clinical trials were limited and largely attributable to paracrine effects. The next generation of stem cell therapies uses CMs derived from human embryonic stem cells or, increasingly, from human-induced pluripotent stem cells (hiPSCs). These cell therapies have shown the ability to engraft more successfully and improve electromechanical function of the heart in preclinical studies, including in non-human primates. Advances in cell culture and delivery techniques promise to further improve the engraftment and integration of hiPSC-derived CMs (hiPSC-CMs), while the use of metabolic selection to eliminate undifferentiated cells will help minimize the risk of teratomas. Clinical trials of allogeneic hiPSC-CMs in HF are now ongoing, providing hope for vast numbers of patients with few other options available.

Confidence in self-care after heart failure hospitalization.

BACKGROUND: Understanding patient perspectives of self-care is critical for improving multidisciplinary education programs and adherence to such programs. However, perspectives of self-care for patients with heart failure (HF) as well as the association between patient perspectives and patient-physician communication remain unclear. METHODS: Confidence levels regarding self-care behaviors (eight lifestyle behaviors and four consulting behaviors) and self-monitoring were assessed using a self-administered questionnaire survey, which was directly distributed by dedicated physicians and nurses to consecutive patients hospitalized with HF in a tertiary-level hospital. Patient-physician communication was evaluated according to the quality of physician-provided information regarding "treatment and treatment choices" and "prognosis" using the Prognosis and Treatment Perception Questionnaire. Out of 202 patients, 187 (92.6 %) agreed to participate, and 176 completed the survey [valid response rate, 87.1 %; male, 67.0 %; median age, 73 (63-81) years]. Multivariate logistic regression analyses were conducted to predict low confidence in self-care (score in the lowest quartile). RESULTS: High confidence (confident or completely confident >75 % of patients) was observed for all self-care behavior categories except low-salt diet (63.1 %), regular exercise (63.1 %), and flu vaccination (65.9 %). Lower confidence in self-care behavior was associated with low quality of patient-physician communication. With regard to self-monitoring, 62.5 % of patients were not confident in distinguishing worsening symptoms of HF from other diseases; non-confidence was also associated with low quality of patient-physician communication. CONCLUSIONS: Hospitalized patients with HF had low confidence regarding regular exercise, salt restriction, and flu vaccination. The results also suggest patient-physician communication affects patient confidence.

Seamless and non-destructive monitoring of extracellular microRNAs during cardiac differentiation from human pluripotent stem cells.

Monitoring cardiac differentiation and maturation from human pluripotent stem cells (hPSCs) and detecting residual undifferentiated hPSCs are indispensable for the development of cardiac regenerative therapy. MicroRNA (miRNA) is secreted from cells into the extracellular space, and its role as a biomarker is attracting attention. Here, we performed an miRNA array analysis of supernatants during the process of cardiac differentiation and maturation from hPSCs. We demonstrated that the quantification of extracellular miR-489-3p and miR-1/133a-3p levels enabled the monitoring of mesoderm and cardiac differentiation, respectively, even in clinical-grade mass culture systems. Moreover, extracellular let-7c-5p levels showed the greatest increase with cardiac maturation during long-term culture. We also verified that residual undifferentiated hPSCs in hPSC-derived cardiomyocytes (hPSC-CMs) were detectable by measuring miR-302b-3p expression, with a detection sensitivity of 0.01%. Collectively, we demonstrate that our method of seamlessly monitoring specific miRNAs secreted into the supernatant is non-destructive and effective for the quality evaluation of hPSC-CMs.

Scalable production of homogeneous cardiac organoids derived from human pluripotent stem cells.

Three-dimensional (3D) cultures are known to more closely mimic in vivo conditions compared with 2D cultures. Cardiac spheroids (CSs) and organoids (COs) are useful for 3D tissue engineering and are advantageous for their simplicity and mass production for regenerative therapy and drug discovery. Herein, we describe a large-scale method for producing homogeneous human induced pluripotent stem cell (hiPSC)-derived CSs (hiPSC-CSs) and COs without scaffolds using a porous 3D microwell substratum with a suction system. Our method has many advantages, such as increased efficiency and improved functionality, homogeneity, and sphericity of hiPSC-CSs. Moreover, we have developed a substratum on a clinically relevant large scale for regenerative therapy and have succeeded in producing approximately 40,000 hiPSC-CSs with high sphericity at once. Furthermore, we efficiently produced a fused CO model consisting of hiPSC-derived atrial and ventricular cardiomyocytes localized on opposite sides of one organoid. This method will facilitate progress toward hiPSC-based clinical applications.

Heart-derived collagen promotes maturation of engineered heart tissue.

Although the extracellular matrix (ECM) plays essential roles in heart tissue engineering, the optimal ECM components for heart tissue organization have not previously been elucidated. Here, we focused on the main ECM component, fibrillar collagen, and analyzed the effects of collagens on heart tissue engineering, by comparing the use of porcine heart-derived collagen and other organ-derived collagens in generating engineered heart tissue (EHT). We demonstrate that heart-derived collagen induces better contraction and relaxation of human induced pluripotent stem cell-derived EHT (hiPSC-EHT) and that hiPSC-EHT with heart-derived collagen exhibit more mature profiles than those with collagens from other organs. Further, we found that collagen fibril formation and gel stiffness influence the contraction, relaxation, and maturation of hiPSC-EHT, suggesting the importance of collagen types III and type V, which are relatively abundant in the heart. Thus, we demonstrate the effectiveness of organ-specific collagens in tissue engineering and drug discovery.

Scalable manufacturing of clinical-grade differentiated cardiomyocytes derived from human-induced pluripotent stem cells for regenerative therapy.

Basic research on human pluripotent stem cell (hPSC)-derived cardiomyocytes (CMs) for cardiac regenerative therapy is one of the most active and complex fields to achieve this alternative to heart transplantation and requires the integration of medicine, science, and engineering. Mortality in patients with heart failure remains high worldwide. Although heart transplantation is the sole strategy for treating severe heart failure, the number of donors is limited. Therefore, hPSC-derived CM (hPSC-CM) transplantation is expected to replace heart transplantation. To achieve this goal, for basic research, various issues should be considered, including how to induce hPSC proliferation efficiently for cardiac differentiation, induce hPSC-CMs, eliminate residual undifferentiated hPSCs and non-CMs, and assess for the presence of residual undifferentiated hPSCs in vitro and in vivo. In this review, we discuss the current stage of resolving these issues and future directions for realizing hPSC-based cardiac regenerative therapy.

Recurrence of Myopericarditis Following mRNA COVID-19 Vaccination in a Male Adolescent.

COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease has spread worldwide, resulting in health and economic crises. Vaccination against SARS-CoV-2 infection is considered a valid prevention measure to control this pandemic. There have been reports of cases of myopericarditis following mRNA COVID-19 vaccination. We present a case of a 20-year-old man with recurrent myopericarditis following an initial episode of influenza virus-induced myopericarditis and after a second dose of the mRNA-1273 Moderna COVID-19 vaccine. Careful attention should be paid to patients with a history of myocarditis following COVID-19 vaccination.

COVID-19 est causée par le coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2). La maladie qui s'est répandue dans le monde a entraîné des crises sanitaire et économique. La vaccination contre l'infection à SRAS-CoV-2 est considérée comme une mesure de prévention valide pour juguler la pandémie. Des cas de myopéricardite ont été déclarés après le vaccin à ARNm contre la COVID-19. Nous présentons le cas d'un homme de 20 ans qui a eu une myopéricardite récurrente après un épisode de myopéricardite induite par le virus de l'influenza et après une deuxième dose du vaccin à ARNm-1273 contre la COVID-19 de Moderna. Il faudrait porter une attention particulière aux patients qui ont des antécédents de myocardite après la vaccination contre la COVID-19.

Apixaban-Associated Diffuse Alveolar Hemorrhage in an Elderly Man with Multiple Complications.

BACKGROUND Diffuse alveolar hemorrhage (DAH) caused by direct oral anticoagulants (DOACs) has increased in recent years with the increase in prescriptions of DOACs. Generally, DOACs are considered to have a lower bleeding risk than the traditional anticoagulant, warfarin. However, major bleeding, including DAH, due to DOACs can be seen in clinical practice, and there are few reports to elucidate when DOAC-associated alveolar hemorrhage occurs and whether DOAC-induced DAH has a trigger. CASE REPORT An 80-year-old man diagnosed and treated for atrial fibrillation with apixaban 2.5 mg twice daily for 1 year before admission, underwent 2 invasive medical procedures over a short period of time. Hemoptysis began after the procedures. He experienced shortness of breath and rapidly progressive hypoxic respiratory failure. His postsurgical oxygen saturation level dropped rapidly. Chest radiography and computed tomography images showed pulmonary infiltration and ground-glass opacity in both lungs. Apixaban treatment was discontinued, and mechanical ventilation was initiated. Bronchoalveolar lavage cytology revealed hemosiderin-laden macrophages. A diagnosis of diffuse alveolar hemorrhage (DAH) was made. In previous reports about DAH caused by DOACs, most patients had bleeding triggers; drug interactions in patients taking DOACs are one of such triggers. Although DOACs are relatively safe for elderly patients, DAH can occur in patients receiving either early-stage or long-term treatment. CONCLUSIONS The onset of DOAC-associated DAH is not limited to the early stages of medication initiation. Various triggers can induce DAH in patients receiving DOACs.