Transplantation of cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSC-CMs) is a promising treatment for heart failure, but residual undifferentiated hiPSCs and malignant ...transformed cells may lead to tumor formation. Here we describe a highly sensitive tumorigenicity assay for the detection of these cells in hiPSC-CMs. The soft agar colony formation assay and cell growth analysis were unable to detect malignantly transformed cells in hiPSC-CMs. There were no karyotypic abnormalities during hiPSCs subculture and differentiation. The hiPSC markers TRA1-60 and LIN28 showed the highest sensitivity for detecting undifferentiated hiPSCs among primary cardiomyocytes. Transplantation of hiPSC-CMs with a LIN28-positive fraction > 0.33% resulted in tumor formation in nude rats, whereas no tumors were formed when the fraction was < 0.1%. These findings suggested that combination of these in vitro and in vivo tumorigenecity assays can verify the safety of hiPSC-CMs for cell transplantation therapy.
Background: This study aimed to elucidate the short-term surgical outcomes and hemodynamics of the Intuity valve compared to the standard bioprosthesis in Japanese patients.Methods and Results: Among ...the 307 consecutive patients who underwent aortic valve replacement (AVR) between February 2019 and March 2021, the Intuity valve was implanted in 95 patients (Intuity group) and a conventional stented bioprosthesis was implanted in 193 patients (conventional group). After propensity score matching, there was no significant difference in in-hospital mortality between the Intuity (n=2, 3%) and conventional groups (n=0, P=0.490). Operation, cardiopulmonary bypass, and aortic cross-clamping times were significantly shorter in the Intuity group. Although the effective orifice area index, trans-prosthetic mean pressure gradient, and peak velocity were similar between the 2 groups at 1 week postoperatively, the Intuity group showed a better mean pressure gradient and peak velocity at 1 year postoperatively. Complete atrioventricular block requiring permanent pacemaker implantation developed in 2 patients (3%) in the Intuity group and none in the conventional group (P=0.476). Mild or greater paravalvular leakage was present in 8 patients (13%) in the Intuity group and 2 patients (3%) in the conventional group (P=0.095).Conclusions: AVR using the Intuity valve in Japanese patients is satisfactory, with a better valve performance and a low incidence of complete atrioventricular block at 1 year postoperatively.
Background:Size-mismatched heart transplantation (HTx) is associated with a risk of stenosis of the caval anastomosis site or low cardiac output syndrome. We developed a modified bicaval anastomosis ...technique (mBCAT) that achieved an adjustable caval anastomosis to compensate for size mismatch. This study was performed to validate the rationale of the mBCAT for size-mismatched HTx.Methods and Results:This institutional consecutive series involved 106 patients who underwent HTx with the mBCAT during an 18-year period. The cohort was divided into 3 groups according to the donor-to-recipient body weight ratio: <0.8, undersized group (n=17); 0.8–1.3, size-matched group (n=68); and >1.3, oversized group (n=21); outcomes were compared. The undersized, size-matched, and oversized groups showed no significant differences in the rate of mild or worse echocardiographic tricuspid regurgitation at 1 month 1 (5.8%), 7 (10.2%), and 1 (4.8%), respectively; P=0.87 or the survival rate at 10 years 100%, 93.9%, and 100%, respectively; P=0.25. The right heart catheter study revealed no pressure gradient across the orifices of both cavae in any patient. Additionally, the cardiac index immediately post-HTx was significantly low in the undersized group (P=0.008), but was similar to the other groups at 6 months post-HTx (P=0.16).Conclusions:The mBCAT prevented caval anastomosis-related complications in size-mismatched HTx and achieved excellent hemodynamics regardless of donor size.
Conversion from peripheral extracorporeal life support (ECLS) to the central one can improve and stabilize hemodynamics in patients with refractory congestive heart failure-related multiorgan ...failure, whereas indication and selection of the type of the central ECLS have not been fully established. Institutional outcome of the conversion therapy was herein reviewed to verify indication and selection of three types of central ECLS. This study enrolled an institutional consecutive surgical series of 24 patients with refractory congestive heart failure under peripheral ECLS, related to fulminant myocarditis (
n
= 15), dilated cardiomyopathy (
n
= 5), or acute myocardial infarction (
n
= 4). They were converted to central Y-extracorporeal membrane oxygenation (ECMO,
n
= 6), extracorporeal ventricular assist device (EC-VAD,
n
= 12), or pump catheter (
n
= 6), dependent upon the degree of multiorgan failure. Despite the different degree of multiorgan failure prior to the conversion, improvement in end-organ perfusion and reduction in right atrial and pulmonary artery pressure were promptly achieved regardless of the type of the central ECLS. There were five in-hospital mortalities (21%) during the central ECLS, whereas mechanical support was weaned-off in 11 cases (46%) and durable LVAD was subsequently implanted for bridge to transplantation in eight cases (33%). Conversion from the peripheral ECLS to the central ones, such as central Y-ECMO, EC-VAD or pump catheter, promptly established a sufficient support with heart and lung unloading in patients with refractory congestive heart failure.
Background:Uncertainties remain regarding the course of existing tricuspid regurgitation (TR) after aortic valve replacement (AVR), and its long-term impact on outcome. We investigated changes in ...existing TR after isolated AVR for severe aortic stenosis (AS), the impact of preoperative TR on long-term outcome, and predictors of late significant TR.Methods and Results:After excluding mild mitral regurgitation and severe TR, 226 consecutive patients undergoing isolated AVR for severe AS between 2002 and 2015 were reviewed. Patients were classified into a non-TR (none/trivial preoperative TR, n=159) and a TR group (mild/moderate preoperative TR, n=67). During follow-up (median, 4.3 years), late significant TR was more prevalent in the TR group (n=20; 35.0%) than in the non-TR group (n=13; 9.6%; HR, 10.0; 95% CI: 4.44–24.7; P<0.001). The TR group developed more right heart failure (n=3; 5% vs. no patients in the non-TR group, P=0.007), and had a decreased estimated glomerular filtration rate (relative to baseline) until 5 years postoperatively. The tricuspid annulus diameter index was an independent predictor of late significant TR development.Conclusions:Preoperative mild or moderate TR is aggravated after isolated AVR, resulting in a high incidence of renal dysfunction and right heart failure. Concomitant tricuspid valve intervention should be considered in patients undergoing AVR for severe AS with mild or moderate TR accompanied by dilated tricuspid annulus.
Although engineered cardiac tissues (ECTs) derived from induced pluripotent stem cells (iPSCs) are promising for myocardial regenerative therapy, the appropriate ratio of cardiomyocytes to ...non-cardiomyocytes is not fully understood. Here, we determined whether ECT-cell content is a key determinant of its structure/function, thereby affecting ECT therapeutic potential for advanced heart failure. Scaffold-free ECTs containing different ratios (25%, 50%, 70%, or 90%) of iPSC-derived cardiomyocytes were generated by magnetic-activated cell sorting by using cardiac-specific markers. Notably, ECTs showed synchronized spontaneous beating when cardiomyocytes constituted ≥50% of total cells, with the electrical-conduction velocity increasing depending on cardiomyocyte ratio; however, ECTs containing 90% cardiomyocytes failed to form stable structures. ECTs containing 25% or 50% cardiomyocytes predominantly expressed collagen and fibronectin, whereas ECTs containing 70% cardiomyocytes predominantly expressed laminin and exhibited the highest contractile/relaxation properties. Furthermore, transplantation of ECTs containing 50% or 70% cardiomyocytes into a rat chronic myocardial infarction model led to a more profound functional recovery as compared with controls. Notably, transplanted ECTs showed electrical synchronization with the native heart under Langendorff perfusion. Collectively, these results indicate that the quantity of non-cardiomyocytes is critical in generating functional iPSC-derived ECTs as grafts for cardiac-regeneration therapy, with ECTs containing 50–70% cardiomyocytes exhibiting stable structures and increased cardiotherapeutic potential.
High-purity cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) are promising for drug development and myocardial regeneration. However, most hiPSC-derived CMs ...morphologically and functionally resemble immature rather than adult CMs, which could hamper their application. Here, we obtained high-quality cardiac tissue-like constructs (CTLCs) by cultivating hiPSC-CMs on low-thickness aligned nanofibers made of biodegradable poly(D,L-lactic-co-glycolic acid) polymer. We show that multilayered and elongated CMs could be organized at high density along aligned nanofibers in a simple one-step seeding process, resulting in upregulated cardiac biomarkers and enhanced cardiac functions. When used for drug assessment, CTLCs were much more robust than the 2D conventional control. We also demonstrated the potential of CTLCs for modeling engraftments in vitro and treating myocardial infarction in vivo. Thus, we established a handy framework for cardiac tissue engineering, which holds high potential for pharmaceutical and clinical applications.
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•hiPSC-CMs are seeded on aligned nanofibers to obtain 3D cardiac tissue-like constructs•Drug assessment using CTLCs can be more robust than conventional cultures•CTLCs can be used to model in vitro cardiac tissue engraftment•CTLCs improve the function of rat hearts with myocardial infarction
Although high-purity cardiomyocytes can be achieved, they are randomly distributed and resemble immature rather than adult CMs. In this article, Liu Li and her colleagues show that 3D and aligned cardiac tissue-like constructs (CTLCs) can be obtained using hPSC-CMs and aligned nanofiber. They also demonstrate the robust drug responses and repair capability of CTLCs in a myocardial infarction model.
Many cell-based therapies are challenged by the poor localization of introduced cells and the use of biomaterial scaffolds with questionable biocompatibility or bio-functionality. Endothelial ...progenitor cells (EPCs), a popular cell type used in cell-based therapies due to their robust angiogenic potential, are limited in their therapeutic capacity to develop into mature vasculature. Here, we demonstrate a joint delivery of human-derived endothelial progenitor cells (EPC) and smooth muscle cells (SMC) as a scaffold-free, bi-level cell sheet platform to improve ventricular remodeling and function in an athymic rat model of myocardial infarction. The transplanted bi-level cell sheet on the ischemic heart provides a biomimetic microenvironment and improved cell-cell communication, enhancing cell engraftment and angiogenesis, thereby improving ventricular remodeling. Notably, the increased density of vessel-like structures and upregulation of biological adhesion and vasculature developmental genes, such as Cxcl12 and Notch3, particularly in the ischemic border zone myocardium, were observed following cell sheet transplantation. We provide compelling evidence that this SMC-EPC bi-level cell sheet construct can be a promising therapy to repair ischemic cardiomyopathy.
Tissue-engineered cardiac constructs have potential in the functional recovery of heart failure; however, the preservation of these constructs is crucial for the development and widespread ...application of this treatment. We hypothesized that tissue-engineered skeletal myoblast (SMB) constructs may be preserved by vitrification to conserve biological function and structure.
Scaffold-free cardiac cell-sheet constructs were prepared from SMBs and immersed in a vitrification solution containing ethylene glycol, sucrose, and carboxyl poly-L-lysine. The cell sheet was wrapped in a thin film and frozen rapidly above liquid nitrogen to achieve vitrification (vitrification group, n = 8); fresh, untreated SMB sheets (fresh group, n = 8) were used as the control. The cryopreserved SMB sheets were thawed at 2 days, 1 week, 1 month, and 3 months after cryopreservation for assessment. Thawed, cryopreserved SMB sheets were transplanted into rat hearts in a myocardial infarction nude rat model, and their effects on cardiac function were evaluated. Cell viability in the cardiac constructs of the vitrification group was comparable to that of the fresh group, independent of the period of cryopreservation (p > 0.05). The structures of the cell-sheet constructs, including cell-cell junctions such as desmosomes, extracellular matrix, and cell membranes, were maintained in the vitrification group for 3 months. The expression of cytokine genes and extracellular matrix proteins (fibronectin, collagen I, N-cadherin, and integrin α5) showed similar levels in the vitrification and fresh groups. Moreover, in an in vivo experiment, the ejection fraction was significantly improved in animals treated with the fresh or cryopreserved constructs as compared to that in the sham-treated group (p < 0.05).
Overall, these results show that the vitrification method proposed here preserves the functionality and structure of scaffold-free cardiac cell-sheet constructs using human SMBs after thawing, suggesting the potential clinical application of this method in cell-sheet therapy.
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