Improvement In Cardiac Function Research Articles

Mitochondrial Transfer Induced by Adipose-Derived Mesenchymal Stem Cell Transplantation Improves Cardiac Function in Rat Models of Ischemic Cardiomyopathy.

Although mesenchymal stem cell transplantation has been successful in the treatment of ischemic cardiomyopathy, the underlying mechanisms remain unclear. Herein, we investigated whether mitochondrial transfer could explain the success of cell therapy in ischemic cardiomyopathy. Mitochondrial transfer in co-cultures of human adipose-derived mesenchymal stem cells and rat cardiomyocytes maintained under hypoxic conditions was examined. Functional recovery was monitored in a rat model of myocardial infarction following human adipose-derived mesenchymal stem cell transplantation. We observed mitochondrial transfer in vitro, which required the formation of cell-to-cell contacts and synergistically enhanced energy metabolism. Rat cardiomyocytes exhibited mitochondrial transfer 3 days following human adipose-derived mesenchymal stem cell transplantation to the ischemic heart surface post-myocardial infarction. We detected donor mitochondrial DNA in the recipient myocardium concomitant with a significant improvement in cardiac function. Mitochondrial transfer is vital for successful cell transplantation therapies and improves treatment outcomes in ischemic cardiomyopathy.

Impacts of delta 9-tetrahydrocannabinol against myocardial ischemia/reperfusion injury in diabetic rats: Role of PTEN/PI3K/Akt signaling pathway.

Despite the current optimal therapy, patients with myocardial ischemia/reperfusion (IR) injury still experience a high mortality rate, especially when diabetes mellitus is present as a comorbidity. Investigating potential treatments aimed at improving the outcomes of myocardial IR injury in diabetic patients is necessary. Our objective was to ascertain the cardioprotective effect of delta 9-tetrahydrocannabinol (THC) against myocardial IR injury in diabetic rats and examine the role of phosphatase and tensin homolog (PTEN)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway in mediating this effect. Diabetes was induced in male Wistar rats (8-10 weeks old, 200-250 g; n = 60) by a single injection of streptozotocin. The duration of the diabetic period was 10 weeks. During the last 4 weeks of diabetic period, rats were treated with THC (1.5 mg/kg/day; intraperitoneally), either alone or in combination with LY294002, and then underwent IR intervention. After 24 h of reperfusion, infarct size, cardiac function, lactate dehydrogenase (LDH) and cardiac-specific isoform of troponin-I (cTn-I) levels, myocardial apoptosis, oxidative stress markers, and expression of PTEN, PI3K, and Akt proteins were evaluated. THC pretreatment resulted in significant improvements in infarct size and cardiac function and decreases in LDH and cTn-I levels (P < 0.05). It also reduced myocardial apoptosis and oxidative stress, accompanied by the downregulation of PTEN expression and activation of the PI3K/Akt signaling pathway (P < 0.05). LY294002 pretreatment abolished the cardioprotective action of THC. This study revealed the cardioprotective effects of THC against IR-induced myocardial injury in diabetic rats and also suggested that the mechanism may be associated with enhanced activity of the PI3K/Akt signaling pathway through the reduction of PTEN phosphorylation.

PS-BPR02-3: NOVEL PULSE WAVEFORM INDEX OBTAINED BY ABPM DEVICE COULD ESTIMATE CARDIAC FUNCTION IN A PATIENT WITH FULMINANT MYOCARDITIS

Introduction: In this case report regarding a patient with fulminant myocarditis who underwent mechanical hemodynamic support including extracorporeal membrane oxygenation (ECMO), our developed novel hemodynamic index calculated from pulse waveform obtained by ambulatory blood pressure monitoring (ABPM) device was useful for estimation of the improvement of cardiac function. We obtained volumetric pulse waveform from diastolic phase of BP measurement by our recently developed device, a Multisensor-ABPM device (TM-2441, A&amp;D Co., Tokyo). This pulse waveform is divided into ejection wave and reflex wave. The area of the ejection part is square forward pulse wave (Sf), which is related with cardiac ejection volume. Second, amplitude measured pulse wave (Am) of the pulse waveform is a parameter defined by central artery compliance, peripheral artery properties, and cuff compliance. We then calculated Sf/Am as follows: Sf was divided by Am to eliminate the effect of arterial and cuff compliance from the area of the ejection wave, which would indicate left ventricular ejective function. Case report: A 43-year-old Asian female presented dyspnea and fever and developed cardiogenic shock. She was transferred from the primary hospital to our intensive care unit. Laboratory test and chest x-ray revealed elevated c-reactive protein, creatine kinase MB, and N-terminal-pro-brain natriuretic peptide and pulmonary edema. Electrocardiogram showed an ST-elevation and there was no stenosis in coronary artery on cardiac catheter examination. Based on these findings, she was diagnosed as viral myocarditis. Her echocardiographic left ventricular ejection fraction (LVEF) decreased less than 20% and hemodynamics were disrupted. Then, she was urgently initiated mechanical support including management of ECMO and intraaortic balloon pumping (IABP). During six-days initiating these mechanical supports, her cardiac function was improved, i.e., LVEF was improved from 6% (almost akinesis) to 64%, and she was able to withdraw from ECMO. We prospectively assessed the changes in the cuff waveform index Sf/Am from during the management of ECMO and IABP. The values of Sf/Am increased in parallel with the improved of LVEF (Figure). Conclusion: This case report highlighted that the novel cuff pulse waveform index Sf/Am obtained by the recent our developed Multisensor-ABPM device was useful for estimation of cardiac function in a patient with fulminant myocarditis who had severe cardiac dysfunction and were needed full mechanical support including ECMO. This case indicated that BP measurement device using the cuff-oscillometric method is useful for evaluation of cardiac function even in intensive care settings.

Greater angiogenic and immunoregulatory potency of bFGF and 5-aza-2ʹ-deoxycytidine pre-treated menstrual blood stem cells in compare to bone marrow stem cells in rat model of myocardial infarction

BackgroundThis study is designed to compare the menstrual blood stem cells (MenSCs) and bone marrow stem cells (BMSCs)-secreted factors with or without pre-treatment regimen using basic fibroblast growth factor (bFGF) and 5-aza-2ʹ-deoxycytidine (5-aza) and also regenerative capacity of pre-treated MenSCs and/or BMSCs in a rat model of myocardial infarction (MI).MethodsBMSCs and MenSCs were pre-treated with bFGF and 5-aza for 48 h and we compared the paracrine activity by western blotting. Furthermore, MI model was created and the animals were divided into sham, MI, pre-treated BMSCs, and pre-treated MenSCs groups. The stem cells were administrated via tail vain. 35 days post-MI, serum and tissue were harvested for further investigations.ResultsFollowing pre-treatment, vascular endothelium growth factor, hypoxia-inducible factor-1, stromal cell-derived factor-1, and hepatocyte growth factor were significantly increased in secretome of MenSCs in compared to BMSCs. Moreover, systemic administration of pre-treated MenSCs, leaded to improvement of cardiac function, preservation of myocardium from further subsequent injuries, promotion the angiogenesis, and reduction the level of NF-κB expression in compared to the pre-treated BMSCs. Also, pre-treated MenSCs administration significantly decreased the serum level of Interleukin 1 beta (IL-1β) in compared to the pre-treated BMSCs and MI groups.ConclusionsbFGF and 5-aza pre-treated MenSCs offer superior cardioprotection compare to bFGF and 5-aza pre-treated BMSCs following MI.

Effect of physical exercise on non-linear parameters of heart rate variability in Chronic Obstructive Pulmonary Disease

Background: Chronic Obstructive Pulmonary Disease (COPD) is associated with autonomic nerve dysfunction. Nonlinear methods of heart rate variability (HRV) analysis have been gaining interest as a method of detecting changes in cardiac autonomic nerve function. Regular practice of physical exercise may cause improvement of this impaired autonomic nerve function. Objectives: To assess the effect of physical exercise on nonlinear measures of HRV analysis in male patients with COPD. Methods: This prospective interventional study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka in 2018 on 60 diagnosed male COPD patients aged 40-75 years with disease duration of at least 5 years selected from the Department of Respiratory Medicine, BSMMU, Dhaka. Thirty patients underwent physical exercise (walking for 30 minute and pursed lip and diaphragmatic breathing 10 minuts)for 3 months in addition to standard treatment. Thirty (30) patients received only standard treatment for 3 months. For comparison, 30 age matched apparently healthy males were also enrolled. HRV data of all patients were recorded before and after 3 months of follow up. HRV data of healthy controls were recorded once at baseline. For assessing autonomic dysfunction, nonlinear parameters of HRV were recorded by Power Lab 8/35. For statistical analysis, paired sample t-test and independent sample t-test were done as applicable. Results: SD1, SD2 and SD1/ SD2 were found significantly lower in COPD patients compared to healthy controls at baseline. After 3 months of physical exercise, significant increment of these parameters occurred with a trend of improvement in cardiac autonomic nerve function in these patients. Conclusion: This study concluded that physical exercise can improve cardiac autonomic nerve dysfunction function in COPD patients. J Bangladesh Soc Physiol. 2022, June; 17(1): 6-13

Circulating MicroRNA-122-5p Is Associated With a Lack of Improvement in Left Ventricular Function After Transcatheter Aortic Valve Replacement and Regulates Viability of Cardiomyocytes Through Extracellular Vesicles.

Transcatheter aortic valve replacement (TAVR) is a well-established treatment option for high- and intermediate-risk patients with severe symptomatic aortic valve stenosis. A majority of patients exhibit improvements in left ventricular ejection fraction (LVEF) after TAVR in response to TAVR-associated afterload reduction. However, a specific role for circulating microRNAs (miRNAs) in the improvement of cardiac function for patients after TAVR has not yet been investigated. Here, we profiled the differential expression of miRNAs in circulating extracellular vesicles (EVs) in patients after TAVR and, in particular, the novel role of circulating miR-122-5p in cardiomyocytes. Circulating EV-associated miRNAs were investigated by use of an unbiased Taqman-based human miRNA array. Several EV miRNAs (miR-122-5p, miR-26a, miR-192, miR-483-5p, miR-720, miR-885-5p, and miR-1274) were significantly deregulated in patients with aortic valve stenosis at day 7 after TAVR compared with the preprocedural levels in patients without LVEF improvement. The higher levels of miR-122-5p were negatively correlated with LVEF improvement at both day 7 (r=-0.264 and P=0.015) and 6 months (r=-0.328 and P=0.0018) after TAVR. Using of patient-derived samples and a murine aortic valve stenosis model, we observed that the expression of miR-122-5p correlates negatively with cardiac function, which is associated with LVEF. Mice with graded wire injury-induced aortic valve stenosis demonstrated a higher level of miR-122-5p, which was related to cardiomyocyte dysfunction. Murine ex vivo experiments revealed that miR-122-5p is highly enriched in endothelial cells compared with cardiomyocytes. Coculture experiments, copy-number analysis, and fluorescence microscopy with Cy3-labeled miR-122-5p demonstrated that miR-122-5p can be shuttled through large EVs from endothelial cells into cardiomyocytes. Gain- and loss-of-function experiments suggested that EV-mediated shuttling of miR-122-5p increases the level of miR-122-5p in recipient cardiomyocytes. Mechanistically, mass spectrometry, miRNA pulldown, electrophoretic mobility shift assay, and RNA immunoprecipitation experiments confirmed that miR-122-5p interacts with the RNA-binding protein hnRNPU (heterogeneous nuclear ribonucleoprotein U) in a sequence-specific manner to encapsulate miR-122-5p into large EVs. On shuttling, miR-122-5p reduces the expression of the antiapoptotic gene BCL2 by binding to its 3' untranslated region to inhibit its translation, thereby decreasing the viability of target cardiomyocytes. Increased levels of circulating proapoptotic EV-incorporated miR-122-5p are associated with reduced LVEF after TAVR. EV shuttling of miR-122-5p regulates the viability and apoptosis of cardiomyocytes in a BCL2-dependent manner.

Drastic improvement of cardiac function after living-donor renal transplantation in a long-term hemodialysis patient with severe mitral regurgitation.

Although there are reports of recovery of cardiac function after renal transplantation, the feasibility of renal transplantation in patients with low cardiac function remains controversial. A 59-year-old Japanese male was scheduled to undergo living-donor renal transplantation (LDRT) under general anesthesia. Preoperative transthoracic echocardiography revealed severe mitral regurgitation (MR) and a left ventricular ejection fraction (LVEF) at 30%. LDRT was conducted prior to cardiac surgery with restrictive fluid management and close monitoring of cardiac function. The patient's renal function improved promptly after the LDRT, and his hemodynamics were stable throughout the perioperative period. Along with improvements in the patient's renal function and anemia, the patient's cardiac function improved to LVEF 50% and achieved drastically improved MR as well as cardiac function, without intervention. This case indicates that LDRT has the potential to improve cardiac function in patients who have been on hemodialysis for more than 20 years.

Retinoic acid released from self-assembling peptide activates cardiomyocyte proliferation and enhances repair of infarcted myocardium

The limited cardiomyocyte proliferation is insufficient for repair of the myocardium. Therefore, activating cardiomyocyte proliferation might be a reasonable option for myocardial regeneration. Here, we investigated effect of retinoic acid (RA) on inducing adult cardiomyocyte proliferation and assessed efficacy of self-assembling peptide (SAP)-released RA in activating regeneration of the infarcted myocardium. Effect of RA on inducing cardiomyocyte proliferation was examined with the isolated cardiomyocytes. Expression of the cell cycle-associated genes and paracrine factors in the infarcted myocardium was examined at one week after treatment with SAP-carried RA. Cardiomyocyte proliferation, myocardial regeneration and improvement of cardiac function were assessed at four weeks after treatment. In the adult rat myocardium, expression of RA synthetase gene Raldh2 and RA concentration were decreased significantly. After treatment with RA, the proliferated cardiomyocytes were increased. The formulated SAP could sustainedly release RA. After treatment with SAP-carried RA, expression of the pro-proliferative genes in cell cycle and paracrine factors in the infarcted myocardium were up-regulated. Myocardial regeneration was enhanced, and cardiac function was improved significantly. These results demonstrate that RA can induce adult cardiomyocytes to proliferate effectively. The sustained release of RA with SAP is a promise strategy to enhance repair of the infarcted myocardium.

Distinct Transcriptomic and Proteomic Profile Specifies Patients Who Have Heart Failure With Potential of Myocardial Recovery on Mechanical Unloading and Circulatory Support.

Extensive evidence from single-center studies indicates that a subset of patients with chronic advanced heart failure (HF) undergoing left ventricular assist device (LVAD) support show significantly improved heart function and reverse structural remodeling (ie, termed "responders"). Furthermore, we recently published a multicenter prospective study, RESTAGE-HF (Remission from Stage D Heart Failure), demonstrating that LVAD support combined with standard HF medications induced remarkable cardiac structural and functional improvement, leading to high rates of LVAD weaning and excellent long-term outcomes. This intriguing phenomenon provides great translational and clinical promise, although the underlying molecular mechanisms driving this recovery are largely unknown. To identify changes in signaling pathways operative in the normal and failing human heart and to molecularly characterize patients who respond favorably to LVAD unloading, we performed global RNA sequencing and phosphopeptide profiling of left ventricular tissue from 93 patients with HF undergoing LVAD implantation (25 responders and 68 nonresponders) and 12 nonfailing donor hearts. Patients were prospectively monitored through echocardiography to characterize their myocardial structure and function and identify responders and nonresponders. These analyses identified 1341 transcripts and 288 phosphopeptides that are differentially regulated in cardiac tissue from nonfailing control samples and patients with HF. In addition, these unbiased molecular profiles identified a unique signature of 29 transcripts and 93 phosphopeptides in patients with HF that distinguished responders after LVAD unloading. Further analyses of these macromolecules highlighted differential regulation in 2 key pathways: cell cycle regulation and extracellular matrix/focal adhesions. This is the first study to characterize changes in the nonfailing and failing human heart by integrating multiple -omics platforms to identify molecular indices defining patients capable of myocardial recovery. These findings may guide patient selection for advanced HF therapies and identify new HF therapeutic targets.

SERCA2a directs the cardioprotective role of nano-emulsion curcumin against PM2.5-induced cardiac injury in rats by prohibiting PERK-eIF2α pathway

AimsActivation of endoplasmic reticulum stress (ERS) by particulate matter 2.5 (PM2.5) has recently been linked to an increased risk of heart problems. Although the PERK- eIF2α pathway is known to be involved in ERS, its crucial role in the pathogenesis of PM2.5-induced cardiotoxicity remains unclear. With the expected potentiality of SERCA2a to modulate ERS via inhibiting the PERK-eIF2α axis, this study intended to assess the possible cardioprotective efficacy of nano-emulsion curcumin (NEC), as a SERCA2a activator, against PM2.5-induced heart damage. Main methodsThirty rats were specified into: Vehicle (V); Blank Filter (BF); NEC; PM and NEC + PM. Cardiac biomarkers as PTX3 and cTnI were assayed. The oxidant/antioxidant status was evaluated via detecting Nrf2/HO-1 axis, as well as MDA and TAC. In addition, the protein expressions of PLN, DWORF, SERCA2a, PERK/eIF2α/ATF4/CHOP, and PI3K/AKT/mTOR in the heart were assessed by western blotting. The levels of inflammatory cytokines (TNF-α and IL-1β) and apoptotic markers were also determined. For detecting PM and NEC particles, cardiac tissues were examined using TEM. Key findingsThe results revealed that NEC markedly alleviated the oxidative stress following PM2.5 exposure, up-regulated DWORF, and produced a significant improvement in cardiac functions. Through activating SERCA2a, NEC could hinder ERS, ameliorate PM2.5-associated cardiac inflammation and myocardial apoptosis by suppressing Bax/Bcl-2 ratio and caspase-3 expression, as well as inhibiting autophagy. SignificanceThese findings revealed that NEC may have a SERCA2a-dependent cardioprotective effect against PM2.5-induced cardiac injury via inhibiting the PERK-eIF2 pathway.

Effects of sacubitril/valsartan in ESRD patients undergoing hemodialysis with HFpEF.

Heart failure with preserved ejection fraction (HFpEF), which is a common co-morbidity in patients with maintenance hemodialysis (MHD), results in substantial mortality and morbidity. However, there are still no effective therapeutic drugs available for HFpEF currently. Sacubitril/valsartan has been shown to significantly improve clinical outcomes and reverse myocardial remodeling among patients with heart failure with reduced ejection fraction (HFrEF). The effect of sacubitril/valsartan in MHD patients with HFpEF remains unclear. Our study was designed to assess the efficacy and safety of sacubitril/valsartan in MHD patients with HFpEF. A total of 247 MHD patients with HFpEF treated with sacubitril/valsartan were included in this retrospective study. Patients were followed up regularly after medication treatment. The alterations in clinical, biochemical, and echocardiographic parameters before and after taking sacubitril/valsartan were collected. In addition, the safety of the sacubitril/valsartan treatment was also assessed. Among those 247 patients with MHD, 211 patients were already in treatment with angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARBs) before being treated with sacubitril/valsartan. We also performed an analysis to compare the differences between the 211 patients who had previously received ACEi/ARB treatment and the 36 patients who were sacubitril/valsartan naive. Among those 247 patients with MHD, compared with baseline levels, systolic blood pressure (BP) (149.7 ± 23.6 vs. 137.2 ± 21.0 mmHg, P < 0.001), diastolic BP (90.2 ± 16.1 vs. 84.5 ± 14.1 mmHg, P < 0.001), heart rate (83.5 ± 12.5 vs. 80.0 ± 8.7 bpm, P < 0.001), N-terminal B-type natriuretic peptide precursor (NT-proBNP) [29125.0 (11474.5, 68532.0) vs. 12561.3 (4035.0, 37575.0) pg/ml, P < 0.001], and cardiac troponin I [0.044 (0.025, 0.078) vs. 0.0370 (0.020, 0.064) μg/L, P = 0.009] were markedly decreased after treatment with sacubitril/valsartan. New York Heart Association (NYHA) functional class showed a notable trend of improvement after 3-12 months of follow-up. Echocardiographic parameters including left ventricular posterior wall thickness (LVPWT) (11.8 ± 2.0 vs. 10.8 ± 1.9 mm, P < 0.001), intraventricular septal thickness in diastole (11.8 ± 2.0 vs. 11.2 ± 2.0 mm, P < 0.001), left ventricular end-diastolic diameter (53.8 ± 6.9 vs. 51.2 ± 7.1 mm, P < 0.001), left atrial diameter (LAD) (40.5 ± 6.2 vs. 37.2 ± 7.2 mm, P < 0.001), left ventricular end-diastolic volume (LVEDV) [143.0 (111.5, 174.0) vs. 130.0 (105.0, 163.0) ml, P < 0.001], left ventricular end-systolic volume (LVESV) [57.0 (43.0, 82.5) vs. 48.0 (38.0, 74.0) ml, P < 0.001], and pulmonary arterial systolic pressure [39.0 (30.5, 50.0) vs. 28.0 (21.0, 37.5) mmHg, P < 0.001] were significantly reduced after initiating the treatment of sacubitril/valsartan. The parameters of left ventricular diastolic function including E/A ratio [0.8 (0.7, 1.3) vs. 0.9 (0.8, 1.3), P = 0.008], maximal tricuspid regurgitation velocity [2.7 (2.5, 3.2) vs. 2.4 (2.0, 2.8) m/s, P < 0.001], septal e'wave velocity (8.0 ± 0.6 vs. 8.2 ± 0.5 cm/s, P = 0.001), lateral e' wave velocity (9.9 ± 0.8 vs. 10.2 ± 0.7 cm/s, P < 0.001), E/e' [8.3 (6.4, 11.8) vs. 7.2 (6.1, 8.9), P < 0.001], and left atrial volume index (37.9 ± 4.2 vs. 36.4 ± 4.1 ml/m2, P < 0.001) were significantly improved by sacubitril/valsartan. Among 211 patients who were already in treatment with ACEi/ARB and 36 patients who were sacubitril/valsartan naive, the improvement of cardiac function demonstrated by clinical outcomes and echocardiographic parameters were similar to the previous one of the 247 MHD patients with HFpEF. During the follow-up, none of the patients showed severe adverse drug reactions. Our study suggested that sacubitril/valsartan treatment in MHD patients with HFpEF was effective and safe.

Abstract 13346: Long Term, Synergistic Benefit of Transmyocardial Laser Revascularization and Platelet Rich Plasma - Significant Improvement of Global Longitudinal Strain in Coronary Artery Bypass Graft Patients

Introduction: Transmyocardial revascularization (TMR) is a procedure designed to treat patients with end-stage coronary artery disease (CAD). TMR creates myocardial micropores which undergo endothelialization and redistribute ischemic stress, thereby improving regional wall motion. Autologous platelet rich plasma (PRP) growth factors contribute to endothelialization and neovascularization. In this study, we evaluate the effectiveness of TMR combined with PRP to improve cardiac function in patients undergoing CABG using echocardiograms. Methods: A single-center, single surgeon retrospective analysis of CABG patients was performed (2019-2021). Patients in the TMR group had ten channels (7 Watts/channel) created in the infero-lateral wall of the left ventricle (LV) and those in the PRP group had autologous PRP extract injected(1ml, without calcium) in the same area. In patients treated with both TMR and PRP, ten channels were made in the inferolateral LV with PRP extract injected in the peri-TMR zone, 5mm adjacent to the channels. Post-operative ejection fraction (EF) and global longitudinal strain (GLS) were measured using speckle tracking up to one year. Results: Fifty-two patients (71% men, mean age 66y ±9.04y) were enrolled in the study and randomized to four experimental groups: CABG only (n=16); CABG/TMR (n=17); CABG/PRP (n=10); and CABG/TMR/PRP (n=9). At one-year follow-up, patients treated with both TMR and PRP had a significant improvement in average GLS (-15.96, p= 0.02) compared to TMR alone (-13.78, p= 0.26) and PRP alone (-15.79, p= 0.08). Patients treated with TMR and PRP also had a significant rise in post-operative EF (57.78%, SD +/- 6.18) compared to TMR alone (55.0%, SD +/- 6.85) and PRP alone (49.5%, SD +/- 11.65). Conclusions: TMR with PRP extract treatment at the time of CABG confers a significant one year improvement in cardiac function as measured by LVEF and GLS. These outcome metrics highlight cardiac remodeling and can mitigate the incidence of heart failure readmissions. With further prospective trials and longer follow-up periods, concomitant adjunctive TMR with PRP extract therapy at time of CABG may have durable and significant cardiac scar remodeling benefits leading to heart recovery in CABG patients.

Abstract 10588: Pre-Clinical Study of Induced Pluripotent Stem Cell-Derived Cardiomyocyte Sheet Transplantation for a Cynomolgus Macaque Model of Doxorubicin-Induced Dilated Cardiomyopathy

Introduction: Due to the serious shortage of cardiac donors in Japan, there is a strong demand for an effective alternative treatment to heart transplantation (HTx) and left ventricular assist device for end-stage severe heart failure. We have conducted induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) sheet transplantation for ischemic cardiomyopathy as first in human clinical trial (jRCT2053190081), based on several pre-clinical studies suggesting both of angiogenic effects and mechanical contribution of iPSC-CMs. Then, we are next aiming to expand the indication for dilated cardiomyopathy (DCM), which is the most common indication for HTx worldwide. In this study, we established a cynomolgus macaque model of Doxorubicin (Dox)-induced DCM and performed the iPSC-CM sheet transplantation. Methods: Twelve male cynomolgus macaques were treated with Dox to induce DCM every two weeks for three consecutive days in three different doses. The cardiac function was assessed over time by transthoracic echocardiography (TTE) and the effect of doxorubicin on the myocardium was investigated with histological analysis. After the establishment of animal model, we performed the iPSC-CM sheet transplantation and assessed the postoperative cardiac function by TTE and cardiac computed tomography (CT). Results: Each Two macaques treated with high (1.2 kg/mg/day) and medium (1.0 kg/mg/day) dose of Dox died before the establishment of animal model. Of the remaining eight macaques in the low dose (0.8 kg/mg/day) group, six had progressively decreased cardiac function. Histology revealed vacuolization in the left ventricle of the Dox-treated heart. Postoperative evaluation two weeks after iPSC-CM sheet transplantation revealed the improvement in cardiac function on TTE and cardiac CT (left ventricular ejection fraction: from 22 % to 31%, and from 19 % to 31 %, respectively). Conclusions: Three-month administration of low-dose Dox was able to create a cynomolgus macaque model of Dox-induced DCM with relatively high reproducibility. IPSC-CM sheet transplantation may have the possibility for improving cardiac function of DCM.

Abstract 15201: Empagliflozin Improves Baroreflex Sensitivity and Heart Function in Infarcted Rats

Introduction: Several experimental studies have shown improvement in cardiac function of infarcted animals (diabetic or not) when treated with empagliflozin. Likewise, several clinical studies have shown improved outcomes in patients with heart failure with reduced ejection fraction or preserved ejection fraction in patients using empagliflozin. Methods: Wistar rats were divided into 2 groups: AMI - acute myocardial infarction (n=8) and EMPA - acute myocardial infarction + Empagliflozin (n=9).The animals of both groups were anesthetized and submitted to thoracotomy and ligature of the left coronary artery. The animals in the EMPA group received 10 mg/kg of empagliflozin daily through oral gavage for 14 days. After this period, an echocardiographic examination was performed, followed by cannulation of the femoral vein and artery, to evaluate hemodynamic parameters and baroreflex activity. Data were compared using unpaired t test or Mann-Whitney test and considered significant when p&lt;0,05. Results: In the echocardiographic evaluation, an improvement in the systolic function indices was observed in the EMPA group in comparison to the AMI group: SF (27.42% ± 3.117 vs 19.17% ± 0.857), EF (50.69% ± 4.848 vs 37.95% ± 1.528), FAC (38.46% ± 2.382 vs 23.65 ± 1.415), as well as diastolic function indices: E'/A' ratio (1.571 ± 0.156 vs 0.574 ± 0.040) E/E' ratio: (16.24 ± 2.461 vs 28.27 ± 2.788).A reduction in mean arterial pressure was observed in the EMPA group (85.96 mmHg ± 1.437) in comparison to the AMI group (92.21 mmHg ± 2.345).In addition, there was an improvement in the baroreflex mediated tachy and bradycardic responses in the treated animals: tachycardic response (4.957 bpm/mmHg ± 0.125 vs 3.243 bpm/mmHg ± 0.157) and bradycardic response (1.532 bpm/mmHg ± 0.058 vs 0.710 bpm/ mmHg ± 0.017). Conclusions: Empagliflozin treatment in infarcted rats improved left ventricular systolic and diastolic function and improved baroreflex sensitivity.

Abstract 13864: Can Catheter Ablation Be Effective in Patients With Persistent Atrial Fibrillation and Heart Failure With Preserved Ejection Fraction Diagnosed Using HFA-PEFF Score?

Background: The efficiency of atrial fibrillation (AF) ablation for heart failure with preserved ejection fraction (EF) (HFpEF) has not been well investigated due to the difficulty of diagnosing HFpEF. The HFA-PEFF score from the European Society of Cardiology has been introduced as a new non-invasive diagnostic system for HFpEF. Methods: We studied 101 persistent AF patients with EF≥50% who underwent first catheter ablation (age 70±10 years, 68 men). The HFA-PEFF score was calculated as a sum of points in echocardiographic functional and morphological, and biomarker (brain natriuretic peptide: BNP) domains. Based on the HFA-PEFF score, patients were divided into High-group (score of ≥5, n=34) and Low-group (score of &lt;5, n=67). Results: The High-group had older, higher BNP levels, left atrial volume index (LAVI), and E/e' than those in the Low-group. However, after 1.1±0.3 procedures, BNP levels (335±247 to 111±95 vs. 167±107 to 90±134pg/mL) and LAVI (62±19 to 44±12 vs. 52±22 to 42±17ml/m 2 ) were significantly decreased in each (all p&lt;0.05 by paired t-test) and reached levels that were not significantly different in both groups. In addition, during 13.9±15.6 months after the first procedure, although recurrences of AF/atrial tachycardia were observed in 28 patients, the Kaplan-Meier curve analysis revealed no significant difference in recurrence-free survival between the two groups (Log-rank p=0.944, Figure). Conclusion: These data suggest that AF catheter ablation is effective even in patients diagnosed with HFpEF by a high HFA-PEFF score in terms of maintaining sinus rhythm comparable to patients with lower scores and improvements in cardiac function.

Abstract 14981: Stk25 Regulates Cell Survival in Both Human and Mouse Models of Myocardial Injury

Introduction: Dysregulation of cardiac kinases occurs in cardiovascular diseases including hypertrophy, remodeling and ischemia injury. Serine/threonine protein kinase 25 (STK25) is a stress response kinase and putative tumor suppressor that regulates cell survival and metabolism through several signaling pathways, including LATS/3HIPPO and mTOR pathways. Hypothesis: STK25 regulates cell survival, metabolism and cardiac function in human cardiomyocytes and animal injury models. Methods: CRISPR-Cas9 was used to generate a homozygous knockout (KO) of STK25 in induced pluripotent stem cell (iPSC) which were then differentiated into cardiomyocytes (iPSC-CMs). STK25 was quantified in human left ventricular tissue from heart failure (HF) patients. Stk25 KO mice were generated by CRISPR/Cas9 mediated genome engineering in C57BL/6J background. Role of STK25 in gene expression, cell proliferation/apoptosis, metabolism and cardiac function were characterized. Results: Gene set enrichment analysis (GSEA) of differential gene expression obtained by RNA-seq was used to identify upregulation of several growth and metabolism pathways in STK25KO iPSC-CMs including oxidative phosphorylation, mTORC1 signaling and myogenesis. In functional assays, STK25 modulated cell cycle progression, proliferation, hypoxia induced apoptosis, and mitochondrial respiration in iPSC-CMs. n a myocardial infarction model of cardiac injury, loss of Stk25 in vivo led to improvements in cardiac function, reduced cardiomyocyte death and diminished fibrosis. STK25 expression is increased in HF patients. Furthermore, loss of function mutations in STK25 were discovered in atrial myxomas, demonstrating STK25 altered regulation in human heart diseases. Conclusions: STK25 regulates cardiomyocyte survival in vitro and in vivo and is aberrantly regulated in both hearth failure and atrial myxomas.

Abstract 11466: CBSCs Derived Extracellular Vesicles Modify the Immune Response After Cardiac Ischemic Injury to Enhance Repair

Introduction: Few therapies have produced significant improvement in cardiac function after ischemic cardiac injury (ICI). The activation of local inflammatory responses is critical to cardiac repair after ICI. Our previous studies showed that cortical bone derived stem cells (CBSCs) possess can enhance repair after ICI. Beneficial effects of CBSCs appear to be mediated by paracrine factors including extracellular vesicles (EVs). This study explored if and how these EVs enhance cardiac repair by modulating the ICI immune response. Hypothesis: CBSCs derived extracellular vesicles (CBSC-EV) modulate immune response after ICI. Methods and Results: Both CBSCs and CBSC-EV were transplanted into mice after myocardial infarction (MI). CBSCs and CBSC-EV treated animals had better ICI repair compared with Saline, with reduced scar size, attenuated structural remodeling, improved cardiac function, and reduced cell apoptosis. These effects were linked to alteration of immune response. Plasma analysis of CBSCs and CBSC-EV treated animals showed significantly lower level of pro-inflammatory cytokines such as TNFα 24 hours after MI. CBSCs and CBSC-EV treatment induced significant polarization from CD86+ M1 macrophages towards CD206+ M2 macrophages phenotype 5 days post-MI, with subsequent reduction of CD8+ T cells and increase of CD4+ T cells, especially the FoxP3+ Treg population, from 7 days to 14 days post-MI. RNA sequencing analysis revealed that CBSC-EV contained a distinct transcriptome compared with endothelial progenitor cells and cardiosphere-derived cells. Gene Ontology analysis suggested the differentially expressed genes in CBSC-EV significantly enriched in immune cell receptor binding. MiR-182 and miR-183, which ranked top of the most significantly upregulated genes in CBSC-EV, attenuated M1 macrophage polarization after LPS treatment and promote CD25+ FoxP3+ Treg differentiation in vitro. Conclusions: CBSC-EV enhance cardiac repair by modulating the immune response after injury and highlight the molecular bases of into the beneficial effects of cell-free therapy after ICI.

Abstract 13470: Circulating microRNA-122-5p is Associated With a Lack of Improvement in Left-Ventricular Function After Transcatheter Aortic Valve Replacement and Regulates Viability of Cardiomyocytes via Extracellular Vesicles

Transcatheter aortic valve replacement is a well-established treatment option for high- and intermediate-risk patients with severe symptomatic AVS. However, a specific role for circulating microRNAs in the improvement of cardiac function for patients after TAVR has not yet been investigated. Methods: Circulating EV-associated miRNAs were investigated by using an unbiased Taqman-based human miR array. Several EV-miRNAs were significantly deregulated in AVS patients on day seven after TAVR in comparison to the pre-procedural levels in patients without LVEF-improvement. The higher levels of miR-122-5p were negatively correlated with LVEF improvement at both day seven (r=-0.264 and p=0.015) and at six months (r=-0.328 and p=0.0018). Results: By utilization of patient-derived samples and a murine AVS model, we observed that the expression of miR-122-5p correlates negatively with cardiac function, which is associated with LVEF. Graded wire-injury-induced AVS mice demonstrated a higher level of miR-122-5p, which was related to cardiomyocyte dysfunction. Murine ex vivo experiments revealed that miR-122-5p is highly enriched in ECs in comparison to cardiomyocytes. Co-culture, copy-number analysis, and immunofluorescence demonstrated that miR-122-5p can be shuttled via large EVs from ECs into cardiomyocytes. Gain- and loss-of-function suggested that EV-shuttling of miR-122-5p increases the level of miR-122-5p in recipient cardiomyocytes. Mechanistically, mass spectrometry, miR-pull down, EMSA, and RNA-IP experiments confirmed that miR-122-5p interacts with the RBP, hnRNPU, in a sequence-specific manner to encapsulate miR-122-5p into large EVs. Upon shuttling, miR-122-5p reduces the expression of the anti-apoptotic gene BCL2 , by binding to its 3' untranslated region to inhibit its translation. Conclusion: Increased levels of circulating pro-apoptotic EV-incorporated miR-122-5p are associated with reduced LVEF after TAVR.

Abstract 12785: Psat1 Promotes Serine Synthesis Pathway and Cardiac Regeneration After Myocardial Infarction

Introduction: Permanent loss of cardiomyocytes (CM) after myocardial infarction (MI) and limited cardiac regenerative capacity lead to heart failure. The iPSC-derived extracellular vesicles (EV) have been shown to improve cardiac function and protection. However, the iPSC-EVs-mediated cardiac function improvement mechanism remains unclear and largely pertains to microRNAs and other RNAs, with a little elucidation of the role of iPSC-EV proteins. Hypothesis: The myocardial delivery of hiPSC-EV-specific protein PSAT1 (phosphoserine aminotransferase 1) induced cardiac regeneration and improved cardiac function post-MI by activating CM proliferation and anti-oxidative stress molecular pathways. Methods and Results: We show that hiPSC-EVs treatment augmented cardiac functions and induced a significant CM cell cycle in mice post-MI. Proteomic analysis identified PSAT1 as a protein expressed exclusively in hiPSC-EVs. The role of PSAT1 in CM proliferation and cardiac regeneration is not studied. The PSAT1 expression was significantly downregulated with heart development. Cardiac delivery of PSAT1 modified mRNA (modRNA) induced a significant CM proliferation post-MI. This increase in the CMs proliferation by the PSAT1 modRNA was associated with reduced scar size, improved cardiac function and CM survival, reduced oxidative stress, and CM apoptosis post-MI. Furthermore, the PSAT1 modRNA inhibited the CM apoptosis by reducing oxidative stress and DNA damage response post-MI. Moreover, we show that the YAP, a master regulator of CM proliferation and cardiac regeneration, binds to the promoter of PSAT1 and induces its expression. Finally, PSAT1 modRNA induced the serine biosynthesis pathway in CMs, resulting in increased nucleotide synthesis and reduced oxidative stress, thereby supporting CM proliferation. Conclusion: Our studies uncover a novel role of hiPSC-EV specific protein PSAT1, and serine synthesis pathway activation leads to post-MI CM proliferation, inhibition of oxidative stress, and improved cardiac function. Furthermore, this work emphasizes the therapeutic prospect of using PSAT1 modRNA as a gene delivery approach for ischemic heart diseases.

Effect of C-type natriuretic peptide and amiodarone in Chinese patients with arrhythmia

Purpose: To compare the effect of C-type natriuretic peptide and amiodarone in Chinese patients with arrhythmia. &#x0D; Method: Chinese men and women aged 18 to 65 years with premature ventricular complexes (PVCs), were administered C-type natriuretic peptide (CNP) - test group or amiodarone (study group) in ratio of 1:1 for 96 h. Patients in CNP group received infusion of synthetic human CNP (10 pmol/kg/min) for an initial 2 h, and then for 30 min every day until discharge. Patients in amiodarone group received initial dose of 1000 mg over the first 24 h. Change in PVCs from baseline was the primary efficacy endpoint. Secondary efficacy endpoint includes: change in PVCs-related symptom scores from baseline, change in ejection fraction of left ventricle (LV), end‑diastolic diameter of LV, and cardiac events as composite outcome (CCE). The effect of both treatments on hemodynamic and electrocardiography parameters, and safety were evaluated. Data from 200 patients were analyzed. &#x0D; Results: The CNP showed significantly greater decrease in the number of PVCs when compared to amiodarone (p &lt; 0.005). Moreover, CNP was superior in alleviating PVCs- related symptoms when compared to amiodarone (p &lt; 0.005). A similar trend of favorable effect of CNP was observed for other endpoints. &#x0D; Conclusion: The C-type natriuretic peptide offers significantly greater benefits of suppressing PVCs and related symptoms, and demonstrates significantly greater improvement of cardiac function and clinical outcome. Thus, CNP can be considered for further investigation as a suitable alternative in the management of ventricular arrhythmia with PVC among Chinese patients.