Predictors of Type 1a Endoleak After Hybrid Thoracic Endovascular Aortic Repair for Aortic Arch Diseases.

BACKGROUND: This study analyzed the risk factors for type 1a endoleak after hybrid thoracic endovascular repair (TEVAR) for aortic arch diseases based on preoperative patient characteristics and multidetector computed tomography measurements. METHODS AND RESULTS: In all, 213 patients who underwent proximal landing zone 1 and 2 hybrid TEVAR for aortic arch pathologies (zone 1, n=82 [38.5%]; zone 2, n=131 [61.5%]; median age 72 years) between May 2008 and February 2020 were enrolled in this study; the median follow-up period was 6.0 years. The rates of type 1a endoleak at 1, 3, 5, and 10 years were 1.4%, 1.4%, 4.1%, and 4.1%, respectively. Multivariate Cox proportional hazard regression analysis revealed that the angle of the aortic arch was a significant risk factor for type 1a endoleak (hazard ratio 1.08; 95% confidence interval 0.85-0.99; P=0.045). The estimated area under the curve in receiver operating characteristic curve analysis was 0.76, and the cut-off value of the aortic arch angle was 95°. CONCLUSIONS: It is essential to prevent type 1a endoleak, the most severe complication of hybrid TEVAR. The risk factor for type 1a endoleak in this study was a sharper angle of the aortic arch (≤95°). For patients at high risk of type 1a endoleak, it is necessary to consider alternative procedures depending on a patient's surgical risk.

Clinical Characteristics and Early Surgical Outcomes of Aortoesophageal Fistula.

BACKGROUND: The incidence and prognosis of aortoesophageal fistula (AEF) has not been clarified. The clinical characteristics and surgical outcomes of AEF were investigated. METHODS: The clinical data of patients who underwent surgical treatment of AEF from January 2020 to December 2021 that were registered in the Japan Cardiovascular Surgery Database (JCVSD) were analyzed. RESULTS: During the period, 123 patients (aged 71.0 years [interquartile range, 61.0-78.0 years]; 76.4% men) underwent surgical treatment of AEF. The prevalence of secondary AEF was 61%. Secondary AEF after aortic grafting was the most frequent (n = 40 [32.5%]), followed by AEF after thoracic endovascular aortic repair (TEVAR; n = 30 [24.4%]). Operative mortality occurred in 23 patients (18.7%). TEVAR for AEF (P = .019). Univariable logistic regression analyses showed postoperative bleeding (P = .047), stroke (P = .004), renal failure (P < .001), newly required hemodialysis (P = .023), pneumonia (P = .003), multisystem failure (P < .001), and dyslipidemia (P = .02) were associated with risk factors of operative mortality after surgical treatment of AEF. CONCLUSIONS: This nationwide study on the surgical treatment of AEF demonstrated a higher incidence of secondary AEF than primary AEF. Open surgical repair and TEVAR for AEF were both associated with high operative mortality. TEVAR and dyslipidemia were risk factors for operative mortality. Precautions and further improved treatment strategies for AEF are still required.

Label-Free Raman Spectroscopy for Assessing Purity and Maturation of hiPSC-Derived Cardiac Tissue.

I. BACKGROUND: Human induced pluripotent stem cell (hiPSC) derived cardiomyocytes (CMs) have been utilized in drug toxicity evaluation, drug discovery, and treating heart failure patients, showing substantial effects. Ensuring the quality, purity, and maturation of hiPSC-CMs during large-scale production is crucial. There is a growing demand for a novel method to characterize cell molecular profiles without labels and without causing damage. II. METHODS: In this study, we employed label-free Raman microscopy to evaluate hiPSC-derived CMs. The study involved the characterization of cell molecular profiles without labels and without causing damage. The correlation between Raman spectroscopy of specific components, such as cytochrome c and myoglobin, and CM purity and maturation following hiPSC differentiation was investigated. Additionally, the validation of this correlation was performed by assessing mixtures of commercially available CMs (iCell cardiomyocytes2) and fibroblasts at various ratios as well as hiPSC-derived CMs with different efficiencies. Furthermore, CMs were matured using rapid pacing of traveling waves, and the Raman profiles of matured CMs were compared to those of immature ones. III. RESULTS: Raman spectroscopy indicated that the cytochrome c and myoglobin showed correlation with the purity and maturation of CMs following differentiation of hiPSCs. This correlation was validated through experiments involving different CM-fibroblast mixtures and hiPSC-derived CMs with varying efficiencies. Moreover, matured CMs exhibited markedly different Raman profiles compared to immature ones, indicating the potential of Raman imaging as a tool for assessing CM maturation. IV. CONCLUSIONS: We discovered that Raman spectroscopy of certain components, such as cytochrome c and myoglobin, correlates with the CM purity and maturation following hiPSC differentiation. The findings of this study highlight the potential of label-free Raman microscopy as a nondestructive, high-content, and time-efficient method for quality control of hiPSC-derived CMs. This approach could significantly contribute to ensuring the quality and maturity of hiPSC-CMs for various applications in drug discovery and regenerative medicine.

CD8+ T cell-mediated rejection of allogenic human-induced pluripotent stem cell-derived cardiomyocyte sheets in human PBMC-transferred NOG MHC double knockout mice.

BACKGROUND: Transplantation of human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) has emerged as a promising therapy to treat end-stage heart failure. However, the immunogenicity of hiPS-CMs in transplanted patients has not been fully elucidated. Thus, in vivo models are required to estimate immune responses against hiPS-CMs in transplant recipients. METHODS: We transferred human peripheral blood mononuclear cells (hPBMCs) into NOD/Shi-scid IL-2rgnull (NOG) MHC class I/II double knockout (NOG-ΔMHC) mice, which were reported to accept hPBMCs without xenogeneic-graft-versus-host disease (xeno-GVHD). Then, hiPS-CM sheets generated from the hiPS cell line 201B7 harboring a luciferase transgene were transplanted into the subcutaneous space of NOG-ΔMHC mice. Graft survival was monitored by bioluminescent images using a Xenogen In Vivo Imaging System. RESULTS: The human immune cells were engrafted for more than 3 months in NOG-ΔMHC mice without lethal xeno-GVHD. The hiPS-CMs expressed a moderate level of human leukocyte antigen (HLA)-class I, but not HLA-class II, molecules even after interferon-gamma (IFN-γ) stimulation. Consistently, the allogenic IFN-γ-treated hiPS-CMs induced weak CD8+ but not CD4+ T cell responses in vitro. hiPS-CM sheets disappeared approximately 17 to 24 days after transplantation in hPBMC-transferred NOG-ΔMHC mice, and CD8+ T cell depletion significantly prolonged graft survival, similar to what was observed following tacrolimus treatment. CONCLUSIONS: hiPS-CMs are less immunogenic in vitro but induce sufficient CD8+ T cell-mediated immune responses for graft rejection in vivo.

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.

Transplantation of Human Embryonic Stem Cell-Derived Pericyte-Like Cells Transduced with Basic Fibroblast Growth Factor Promotes Angiogenic Recovery in Mice with Severe Chronic Hindlimb Ischemia.

Critical limb ischemia (CLI) is a state of severe peripheral artery disease, with no effective treatment. Cell therapy has been investigated as a therapeutic tool for CLI, and pericytes are promising therapeutic candidates based on their angiogenic properties. We firstly generated highly proliferative and immunosuppressive pericyte-like cells from embryonic stem (ES) cells. In order to enhance the angiogenic potential, we transduced the basic fibroblast growth factor (bFGF) gene into the pericyte-like cells and found a significant enhancement of angiogenesis in a Matrigel plug assay. Furthermore, we evaluated the bFGF-expressing pericyte-like cells in the previously established chronic hindlimb ischemia model in which bone marrow-derived MSCs were not effective. As a result, bFGF-expressing pericyte-like cells significantly improved blood flow in both laser Doppler perfusion imaging (LDPI) and dynamic contrast-enhanced MRI (DCE-MRI). These findings suggest that bFGF-expressing pericyte-like cells differentiated from ES cells may be a therapeutic candidate for CLI.

Prevalence of bleeding events in real-world Japanese registry for Percutaneous Ventricular Assist Device.

PURPOSE: Bleeding complication is a critical risk factor for outcomes of acute heart failure patients requiring mechanical circulatory support (MCS), including percutaneous catheter-type heart pumps (Impella). The Japanese registry for Percutaneous Ventricular Assist Device (J-PVAD) is an ongoing, large-scale, real-world registry to characterize Japanese patients requiring Impella. Here we analyzed bleeding complication profiles in patients who received Impella. METHODS: All consecutive Japanese patients who received Impella from October 2017 to January 2020 were enrolled. The 30-day survival and bleeding complications were analyzed. RESULTS: A total of 1344 patients were included: 653 patients received Impella alone, 685 patients received a combination of veno-arterial extracorporeal membrane oxygenation and Impella (ECPELLA), and 6 patients had failed Impella delivery. Overall 30-day survival was 67.0%, with Impella alone at 81.9% and ECPELLA at 52.7%. Overall bleeding/hematoma adverse events with a relation or not-excluded relation to Impella was 6.92%. Among them, the rates of hematoma and bleeding from medical device access sites were 1.41% and 4.09%, respectively. There was no difference between etiologies for these events. CONCLUSION: This study represents the first 3-year survival and the safety profile focused on bleeding adverse events from the J-PVAD registry. The results show that the real-world frequency of bleeding adverse events for patients who received Impella was an expected range from previous reports, and future real-world studies should aim to expand this data set to improve outcomes and adverse events.

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.

Mid-term outcomes of surgical aortic valve replacement using a mosaic porcine bioprosthesis with concomitant mitral valve repair.

This study retrospectively evaluated the mid-term outcomes of surgical aortic valve replacement (SAVR) using a stented porcine aortic valve bioprosthesis (Mosaic; Medtronic Inc., Minneapolis, MN, USA) with concomitant mitral valve (MV) repair. From 1999 to 2014, 157 patients (median [interquartile range] age, 75 [70-79] years; 47% women) underwent SAVR with concomitant MV repair (SAVR + MV repair), and 1045 patients (median [interquartile range] age, 76 [70-80] years; 54% women) underwent SAVR only at 10 centers in Japan as part of the long-term multicenter Japan Mosaic valve (J-MOVE) study. The 5-year overall survival rate was 81.5% ± 4.1% in the SAVR + MV repair group and 85.1% ± 1.4% in the SAVR only group, and the 8-year overall survival rates were 75.2% ± 5.7% and 78.1% ± 2.1%, respectively. Cox proportional hazards analysis showed no significant difference in the survival rates between the two groups (hazard ratio, 0.87; 95% confidence interval, 0.54-1.40; P = 0.576). Among women with mild or moderate mitral regurgitation who were not receiving dialysis, those who underwent SAVR + MV repair, were aged > 75 years, and had a preoperative left ventricular ejection fraction of 30-75% tended to have a lower mortality risk. In conclusion, this subgroup analysis of the J-MOVE cohort showed relevant mid-term outcomes after SAVR + MV repair.

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.

Outcomes of Veno-Arterial Extracorporeal Membrane Oxygenation With Percutaneous Left Ventricular Unloading in Fulminant Myocarditis.

Fulminant myocarditis requiring peripheral veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has a high mortality rate. We investigated clinical outcomes of combined use of VA-ECMO and percutaneous left ventricular assist device (VAD) (Impella) for fulminant myocarditis in 104 consecutive patients enrolled in the Japan Registry for Percutaneous VAD (J-pVAD) between October 2017 and January 2020. Patients were followed until hospital discharge and predictors of survival were analyzed with a Cox proportional hazards model. The median support duration of combined use of VA-ECMO and Impella (ECMO/Impella) was 6 days, and the median left ventricular ejection fraction improved from 15% to 52% during support ( p < 0.0001). Overall, 66 patients (63%) survived to discharge. Multivariate analysis revealed ECMO/Impella support at a transplant center as an independent predictor of survival ( p = 0.0231). Patients treated at transplant centers had better 60 days survival rates when compared to nontransplant centers (83% vs. 55%, p = 0.005). However, baseline characteristics and treatment strategies differed between the two groups. This real-world national registry database suggested the difference in survival after ECMO/Impella support for fulminant myocarditis between transplant and nontransplant centers, which may indicate hospital variations regarding patient management, although further controlled studies are needed.

The Efficacy of Second-Stage Endovascular Repair Strategy for Acute Type A Aortic Dissection.

PURPOSE: To evaluate the usefulness of a hybrid treatment strategy for acute type A aortic dissection (AAAD). METHODS: We retrospectively evaluated the outcomes of 39 partial arch replacements (PAR; 26 male/13 female, mean age=67.9 years) in 62 patients with AAAD operated at our hospital from January 2019 to January 2023. The technique included PAR with graft-designed landing length and translocated the brachiocephalic artery inflow site during the initial surgery to minimize the invasiveness of the surgery. Thereafter, second-stage thoracic endovascular aortic repair (second TEVAR) for distal aortic events in the chronic phase was performed. RESULTS: There was 1 case of 30-day mortality (2.6%) and 2 cases of postprocedural cerebral infarction (5.1%). The cumulative survival rates were 97.4%/1 year and 97.4%/3 years. The cumulative freedom from aorta-related second-stage procedure for the distal aortic event after initial PAR, which was performed in 13 patients (33.3%), was 63.9%/1 year and 59.7%/3 years. All patients requiring re-intervention after initial PAR underwent a second TEVAR with a 100% success rate and no postoperative complications. CONCLUSION: Initial PAR for AAAD in anticipation of the second TEVAR is a valuable strategy for enabling minimally invasive additional treatment of aorta-related re-intervention for distal aortic events in the chronic phase. CLINICAL IMPACT: This study provides detailed information on the hybrid aortic repair strategy of the initial open partial arch repair and second staged endovascular repair for the acute type A aortic dissection. Based on this study, distal aortic re-intervention after initial open partial arch repair was necessary only in about 30% of cases, and no cases of SCI were observed in the initial treatment or in the second-stage endovascular repair and no cases of distal SINE were observed after the second staged endovascular repair. Overall, the results suggest that limiting the initial open partial arch repair can achieve good perioperative and early outcomes of initial surgery, and that second staged endovascular re-intervention for distal aortic events can be performed reliably, safely, and with minimal invasiveness.

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.

Effect of morphological change on the maturation of human induced pluripotent stem cell-derived cardiac tissue in rotating flow culture.

Introduction: Understanding the critical factors for the maturation of human induced pluripotent stem cell (hiPSC)-derived cardiac tissue is important for further development of culture techniques. Rotating flow culture, where the tissues float in the culture medium by balancing its gravitational settling and the medium flow generated in rotating disk-shaped culture vessels, is one of culture systems used for tissue engineering. It has previously been demonstrated that rotating flow culture leads to the formation of matured cardiac tissue with higher levels of function and structure than the other culture systems. However, the detailed mechanisms underlying the maturation of cardiac tissue remain unclear. This study investigated the maturation process of hiPSC-derived cardiac tissue in rotating flow culture with a focus on morphological changes in the tissue, which is a trigger for maturation. Methods: The cardiac tissue, which consisted of cardiomyocytes derived from hiPSCs, was cultured on the 3D scaffold of poly (lactic-co-glycolic) acid (PLGA)-aligned nanofibers, in rotating flow culture for 5 days. During the culture, the time profile of projected area of tissue and formation of maturation marker proteins (ß-myosin heavy chain and Connexin-43), tissue structure, and formation of nuclear lamina proteins (Lamin A/C) were compared with that in static suspension culture. Results: The ratio of the projected area of tissue significantly decreased from Day 0 to Day 3 due to tissue shrinkage. In contrast, Western blot analysis revealed that maturation protein markers of cardiomyocytes significantly increased after Day 3. In addition, in rotating flow culture, flat-shaped nuclei and fiber-like cytoskeletal structures were distributed in the surface region of tissue where medium flow was continuously applied. Moreover, Lamin A/C, which are generally formed in differentiated cells owing to mechanical force across the cytoskeleton and critically affect the maturation of cardiomyocytes, were significantly formed in the tissue of rotating flow culture. Conclusions: In this study, we found that spatial heterogeneity of tissue structure and tissue shrinkage occurred in rotating flow culture, which was not observed in static suspension culture. Moreover, from the quantitative analysis, it was also suggested that tissue shrinkage in rotating flow culture contributed its following tissue maturation. These findings showed one of the important characteristics of rotating flow culture which was not revealed in previous studies.