Single-Cell RNA Sequencing Analysis Reveals a Crucial Role for CTHRC1 (Collagen Triple Helix Repeat Containing 1) Cardiac Fibroblasts After Myocardial Infarction.

BACKGROUND: Cardiac fibroblasts (CFs) have a central role in the ventricular remodeling process associated with different types of fibrosis. Recent studies have shown that fibroblasts do not respond homogeneously to heart injury. Because of the limited set of bona fide fibroblast markers, a proper characterization of fibroblast population heterogeneity in response to cardiac damage is lacking. The purpose of this study was to define CF heterogeneity during ventricular remodeling and the underlying mechanisms that regulate CF function. METHODS: Collagen1α1-GFP (green fluorescent protein)-positive CFs were characterized after myocardial infarction (MI) by single-cell and bulk RNA sequencing, assay for transposase-accessible chromatin sequencing, and functional assays. Swine and patient samples were studied using bulk RNA sequencing. RESULTS: We identified and characterized a unique CF subpopulation that emerges after MI in mice. These activated fibroblasts exhibit a clear profibrotic signature, express high levels of Cthrc1 (collagen triple helix repeat containing 1), and localize into the scar. Noncanonical transforming growth factor-ß signaling and different transcription factors including SOX9 are important regulators mediating their response to cardiac injury. Absence of CTHRC1 results in pronounced lethality attributable to ventricular rupture. A population of CFs with a similar transcriptome was identified in a swine model of MI and in heart tissue from patients with MI and dilated cardiomyopathy. CONCLUSIONS: We report CF heterogeneity and their dynamics during the course of MI and redefine the CFs that respond to cardiac injury and participate in myocardial remodeling. Our study identifies CTHRC1 as a novel regulator of the healing scar process and a target for future translational studies.

Non-invasive in vivo imaging of cardiac stem/progenitor cell biodistribution and retention after intracoronary and intramyocardial delivery in a swine model of chronic ischemia reperfusion injury.

BACKGROUND: The safety and efficacy of cardiac stem/progenitor cells (CSC) have been demonstrated in previous preclinical and clinical assays for heart failure. However, their optimal delivery route to the ischemic heart has not yet been assessed. This study was designed to determine by a non-invasive imaging technique (PET/CT) the biodistribution and acute retention of allogeneic pig CSC implanted by two different delivery routes, intracoronary (IC) and intramyocardial (IM), in a swine preclinical model of chronic ischemia-reperfusion. METHODS: Ischemia-reperfusion was induced in six Goettingen hybrid minipigs by 90 min coronary artery occlusion followed by reperfusion. Thirty days later, animals were allocated to receive IC (n = 3) or NOGA®-guided IM injection (n = 3) of 50 million of 18F-FDG/GFP-labeled allogeneic pig CSC. Acute retention was quantified by PET/CT 4 h after injection and cell engraftment assessed by immunohistochemical quantification of GFP+ cells three days post-injection. RESULTS: Biodistribution of 18F-FDG-labeled CSC was clearly visualized by PET/CT imaging and quantified. No statistical differences in acute cell retention (percentage of injected dose, %ID) were found in the heart when cells were administered by NOGA®-guided IM (13.4 ± 3.4%ID) or IC injections (17.4 ± 4.1%ID). Interestingly, engrafted CSC were histologically detected only after IM injection. CONCLUSION: PET/CT imaging of 18F-FDG-labeled CSC allows quantifying biodistribution and acute retention of implanted cells in a clinically relevant pig model of chronic myocardial infarction. Similar levels of acute retention are achieved when cells are IM or IC administered. However, acute cell retention does not correlate with cell engraftment, which is improved by IM injection.

Renal autotransplant for subsequent endovascular exclusion of the thoracoabdominal aorta.

In the last 20 years, endovascular procedures have radically altered the treatment of diseases of the aorta. The objective of endovascular treatment of dissections is to close the entry point to redirect blood flow toward the true lumen, thereby achieving thrombosis of the false lumen. In extensive chronic dissections that have evolved with the formation of a large aneurysm, the dissection is maintained from the end of the endoprosthesis due to multiple orifices, or reentries, that communicate with the lumens. In addition, one of the primary limitations of this technique is when the visceral arteries have disease involvement. In this report we present a case where, despite having treated the entire length of the descending thoracic aorta, the dissection was maintained distally, leading to progression of the diameter of the aneurysm. After reviewing the literature, and to the best of our knowledge, we describe the first case in which renal autotransplant was performed to allow for subsequent exclusion of the aorta at the thoracoabdominal level using a fenestrated endoprosthesis for the celiac trunk and the superior mesenteric artery.

Systemic lupus erythematosus myocarditis after COVID-19 vaccination.

INTRODUCTION: Cases of acute myocarditis have been after administration of the BNT162b2 and Ad26.COV2.S vaccine. OBJECTIVE: Describe another possible mechanism of myocarditis after COVID-19 vaccination. CASE PRESENTATION: We describe the clinical case of a 72-year-old female with pleuritic chest pain one week after the third of the BNT162b2 mRNA vaccine. Serological tests for cardiotropic pathogens were negative, and autoimmunity screening was positive with anti-nuclear antibody (ANA) in 1:160 dilution, Anti-double-stranded DNA (anti-dsDNA), and anti-histone antibodies. 18F-fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) showed a focal myocardial and pericardial inflammatory process in the cardiac apex. RESULTS AND DISCUSSION: Systemic lupus erythematosus (SLE) diagnosis was made with myocardial affection. As far as we know, this is the first report of a case of lupus myocarditis after the COVID-19 vaccine. CONCLUSION: Given the pathogenic rationales, the association between SLE and myocarditis should be considered.

Systemic lupus erythematosus myocarditis after COVID-19 vaccination.

Introduction: Cases of acute myocarditis have been after administration of the BNT162b2 and Ad26.COV2.S vaccine. Objective: Describe another possible mechanism of myocarditis after COVID-19 vaccination. Case presentation: We describe the clinical case of a 72-year-old female with pleuritic chest pain one week after the third of the BNT162b2 mRNA vaccine. Serological tests for cardiotropic pathogens were negative, and autoimmunity screening was positive with anti-nuclear antibody (ANA) in 1:160 dilution, Anti-double-stranded DNA (anti-dsDNA), and anti-histone antibodies. 18F-fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) showed a focal myocardial and pericardial inflammatory process in the cardiac apex. Results and discussion: Systemic lupus erythematosus (SLE) diagnosis was made with myocardial affection. As far as we know, this is the first report of a case of lupus myocarditis after the COVID-19 vaccine. Conclusion: Given the pathogenic rationales, the association between SLE and myocarditis should be considered.

Introducción: Se han presentado casos de miocarditis aguda tras la administración de las vacunas BNT162b2 y Ad26.COV2.S. Objetivo: Describir otro posible mecanismo de miocarditis posterior a la vacunación contra el COVID-19. Presentación del caso: Describimos el caso clínico de una mujer de 72 años con dolor torácico pleurítico una semana después de la tercera vacuna de ARNm BNT162b2. Las pruebas serológicas para patógenos cardiotrópos fueron negativas y el cribado de autoinmunidad fue positivo con anticuerpos antinucleares (ANA) en dilución 1:160, anticuerpos anti-ADN de doble cadena (anti-dsADN) y antihistonas. La tomografía por emisión de positrones/tomografía computarizada (PET/TC) con 18F-fluorodesoxiglucosa (FDG) mostró un proceso inflamatorio miocárdico y pericárdico focal en el ápex cardíaco. Resultados y discusión: Se realizó el diagnóstico de lupus eritematoso sistémico (LES) con afectación miocárdica. Hasta donde sabemos, este es el primer reporte de un caso de miocarditis lúpica después de la vacuna contra el COVID-19. Conclusión: Dadas las justificaciones patogénicas, se debe considerar la asociación entre lupus eritematoso sistémico (LES) y miocarditis.

[Current status of cardiac resynchronization therapy]. / Estado actual de la terapia de resincronización cardiaca.

The present document reviews various aspects of the current status of cardiac resynchronization therapy: mechanisms of action, current indications and implantation technique.

A Fibrosis Biomarker Early Predicts Cardiotoxicity Due to Anthracycline-Based Breast Cancer Chemotherapy.

Anthracycline-based cancer chemotherapy (ACC) causes myocardial fibrosis, a lesion contributing to left ventricular dysfunction (LVD). We investigated whether the procollagen-derived type-I C-terminal-propeptide (PICP): (1) associates with subclinical LVD (sLVD) at 3-months after ACC (3m-post-ACC); (2) predicts cardiotoxicity 1-year after ACC (12m-post-ACC) in breast cancer patients (BC-patients); and (3) associates with LVD in ACC-induced heart failure patients (ACC-HF-patients). Echocardiography, serum PICP and biomarkers of cardiomyocyte damage were assessed in two independent cohorts of BC-patients: CUN (n = 87) at baseline, post-ACC, and 3m and 12m (n = 65)-post-ACC; and HULAFE (n = 70) at baseline, 3m and 12m-post-ACC. Thirty-seven ACC-HF-patients were also studied. Global longitudinal strain (GLS)-based sLVD (3m-post-ACC) and LV ejection fraction (LVEF)-based cardiotoxicity (12m-post-ACC) were defined according to guidelines. BC-patients: all biomarkers increased at 3m-post-ACC versus baseline. PICP was particularly increased in patients with sLVD (interaction-p < 0.001) and was associated with GLS (p < 0.001). PICP increase at 3m-post-ACC predicted cardiotoxicity at 12m-post-ACC (odds-ratio ≥ 2.95 per doubling PICP, p ≤ 0.025) in both BC-cohorts, adding prognostic value to the early assessment of GLS and LVEF. ACC-HF-patients: PICP was inversely associated with LVEF (p = 0.004). In ACC-treated BC-patients, an early increase in PICP is associated with early sLVD and predicts cardiotoxicity 1 year after ACC. PICP is also associated with LVD in ACC-HF-patients.

Global Circumferential and Radial Strain Among Patients With Immune Checkpoint Inhibitor Myocarditis.

BACKGROUND: Global circumferential strain (GCS) and global radial strain (GRS) are reduced with cytotoxic chemotherapy. There are limited data on the effect of immune checkpoint inhibitor (ICI) myocarditis on GCS and GRS. OBJECTIVES: This study aimed to detail the role of GCS and GRS in ICI myocarditis. METHODS: In this retrospective study, GCS and GRS from 75 cases of patients with ICI myocarditis and 50 ICI-treated patients without myocarditis (controls) were compared. Pre-ICI GCS and GRS were available for 12 cases and 50 controls. Measurements were performed in a core laboratory blinded to group and time. Major adverse cardiovascular events (MACEs) were defined as a composite of cardiogenic shock, cardiac arrest, complete heart block, and cardiac death. RESULTS: Cases and controls were similar in age (66 ± 15 years vs 63 ± 12 years; P = 0.20), sex (male: 73% vs 61%; P = 0.20) and cancer type (P = 0.08). Pre-ICI GCS and GRS were also similar (GCS: 22.6% ± 3.4% vs 23.5% ± 3.8%; P = 0.14; GRS: 45.5% ± 6.2% vs 43.6% ± 8.8%; P = 0.24). Overall, 56% (n = 42) of patients with myocarditis presented with preserved left ventricular ejection fraction (LVEF). GCS and GRS were lower in myocarditis compared with on-ICI controls (GCS: 17.5% ± 4.2% vs 23.6% ± 3.0%; P < 0.001; GRS: 28.6% ± 6.7% vs 47.0% ± 7.4%; P < 0.001). Over a median follow-up of 30 days, 28 cardiovascular events occurred. A GCS (HR: 4.9 [95% CI: 1.6-15.0]; P = 0.005) and GRS (HR: 3.9 [95% CI: 1.4-10.8]; P = 0.008) below the median was associated with an increased event rate. In receiver-operating characteristic (ROC) curves, GCS (AUC: 0.80 [95% CI: 0.70-0.91]) and GRS (AUC: 0.76 [95% CI: 0.64-0.88]) showed better performance than cardiac troponin T (cTnT) (AUC: 0.70 [95% CI: 0.58-0.82]), LVEF (AUC: 0.69 [95% CI: 0.56-0.81]), and age (AUC: 0.54 [95% CI: 0.40-0.68]). Net reclassification index and integrated discrimination improvement demonstrated incremental prognostic utility of GRS over LVEF (P = 0.04) and GCS over cTnT (P = 0.002). CONCLUSIONS: GCS and GRS are lower in ICI myocarditis, and the magnitude of reduction has prognostic significance.

Repeated implantation of skeletal myoblast in a swine model of chronic myocardial infarction.

AIMS: Although transplantation of skeletal myoblast (SkM) in models of chronic myocardial infarction (MI) induces an improvement in cardiac function, the limited engraftment remains a major limitation. We analyse in a pre-clinical model whether the sequential transplantation of autologous SkM by percutaneous delivery was associated with increased cell engraftment and functional benefit. METHODS AND RESULTS: Chronically infarcted Goettingen minipigs (n = 20) were divided in four groups that received either media control or one, two, or three doses of SkM (mean of 329.6 x 10(6) cells per dose) at intervals of 6 weeks and were followed for a total of 7 months. At the time of sacrifice, cardiac function was significantly better in animals treated with SkM in comparison with the control group. A significantly greater increase in the DeltaLVEF was detected in animals that received three doses vs. a single dose of SkM. A correlation between the total number of transplanted cells and the improvement in LVEF and DeltaLVEF was found (P < 0.05). Skeletal myoblast transplant was associated with an increase in tissue vasculogenesis and decreased fibrosis (collagen vascular fraction) and these effects were greater in animals receiving three doses of cells. CONCLUSION: Repeated injection of SkM in a model of chronic MI is feasible and safe and induces a significant improvement in cardiac function.

Preclinical Evaluation of the Safety and Immunological Action of Allogeneic ADSC-Collagen Scaffolds in the Treatment of Chronic Ischemic Cardiomyopathy.

The use of allogeneic adipose-derived mesenchymal stromal cells (alloADSCs) represents an attractive approach for treating myocardial infarction (MI). Furthermore, adding a natural support improves alloADSCs engraftment and survival in heart tissues, leading to a greater therapeutic effect. We aimed to examine the safety and immunological reaction induced by epicardial implantation of a clinical-grade collagen scaffold (CS) seeded with alloADSCs for its future application in humans. Thus, cellularized scaffolds were myocardially or subcutaneously implanted in immunosuppressed rodent models. The toxicological parameters were not significantly altered, and tumor formation was not found over the short or long term. Furthermore, biodistribution analyses in the infarcted immunocompetent rats displayed cell engraftment in the myocardium but no migration to other organs. The immunogenicity of alloADSC-CS was also evaluated in a preclinical porcine model of chronic MI; no significant humoral or cellular alloreactive responses were found. Moreover, CS cellularized with human ADSCs cocultured with human allogeneic immune cells produced no alloreactive response. Interestingly, alloADSC-CS significantly inhibited lymphocyte responses, confirming its immunomodulatory action. Thus, alloADSC-CS is likely safe and does not elicit any alloreactive immunological response in the host. Moreover, it exerts an immunomodulatory action, which supports its translation to a clinical setting.

Myocardial T1 and T2 Mapping by Magnetic Resonance in Patients With Immune Checkpoint Inhibitor-Associated Myocarditis.

BACKGROUND: Myocarditis is a potentially fatal complication of immune checkpoint inhibitor (ICI) therapy. Data on the utility of cardiovascular magnetic resonance (CMR) T1 and T2 mapping in ICI myocarditis are limited. OBJECTIVES: This study sought to assess the value of CMR T1 and T2 mapping in patients with ICI myocarditis. METHODS: In this retrospective study from an international registry of patients with ICI myocarditis, clinical and CMR findings (including T1 and T2 maps) were collected. Abnormal T1 and T2 were defined as 2 SD above site (vendor/field strength specific) reference values and a z-score was calculated for each patient. Major adverse cardiovascular events (MACE) were a composite of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block. RESULTS: Of 136 patients with ICI myocarditis with a CMR, 86 (63%) had T1 maps and 79 (58%) also had T2 maps. Among the 86 patients (66.3 ± 13.1 years of age), 36 (41.9%) had a left ventricular ejection fraction <55%. Across all patients, mean z-scores for T1 and T2 values were 2.9 ± 1.9 (p < 0.001) and 2.2 ± 2.1 (p < 0.001), respectively. On Siemens 1.5-T scanner (n = 67), native T1 (1,079.0 ± 55.5 ms vs. 1,000.3 ± 22.1 ms; p < 0.001) and T2 (56.2 ± 4.9 ms vs. 49.8 ± 2.2 ms; p < 0.001) values were elevated compared with reference values. Abnormal T1 and T2 values were seen in 78% and 43% of the patients, respectively. Applying the modified Lake Louise Criteria, 95% met the nonischemic myocardial injury criteria and 53% met the myocardial edema criteria. Native T1 values had excellent discriminatory value for subsequent MACE, with an area under the curve of 0.91 (95% confidence interval: 0.84 to 0.98). Native T1 values (for every 1-unit increase in z-score, hazard ratio: 1.44; 95% confidence interval: 1.12 to 1.84; p = 0.004) but not T2 values were independently associated with subsequent MACE. CONCLUSIONS: The use of T1 mapping and application of the modified Lake Louise Criteria provides important diagnostic value, and T1 mapping provides prognostic value in patients with ICI myocarditis.

Prognostic role of stress cardiac magnetic resonance in the elderly.

INTRODUCTION AND OBJECTIVES: Several trials have tested the diagnostic and prognostic value of stress cardiac magnetic resonance (CMR) in ischemic heart disease. However, scientific evidence is lacking in the older population, and the available techniques have limitations in this population. The aim of this study was to evaluate the usefulness of stress CMR in the elderly. METHODS: We prospectively studied consecutive patients referred for stress CMR to rule out myocardial ischemia. The cutoff age for the elderly population was 70 years. Stress CMR study was performed according to standardized international protocols. Hypoperfusion severity was classified according to the number of affected segments: mild (1-2 segments), moderate (3-4 segments), or severe (> 4 segments). We analyzed the occurrence of major events during follow-up (death, acute coronary syndrome, or revascularization). Survival was studied with the Kaplan-Meier method and multivariate Cox regression models. RESULTS: Of an initial cohort of 333 patients, 110 were older than 70 years. In 40.9% patients, stress CMR was positive for ischemia. The median follow-up was 26 [18-37] months. In elderly patients there were 35 events (15 deaths, 10 acute coronary syndromes, and 10 revascularizations). Patients with moderate or severe ischemia were at a higher risk of events, adjusted for age, sex, and cardiovascular risk (HR, 3.53 [95%CI, 1.41-8.79]; P=.01). CONCLUSIONS: Moderate to severe perfusion defects in stress CMR strongly predict cardiovascular events in people older than 70 years, without relevant adverse effects.

Cells, Materials, and Fabrication Processes for Cardiac Tissue Engineering.

Cardiovascular disease is the number one killer worldwide, with myocardial infarction (MI) responsible for approximately 1 in 6 deaths. The lack of endogenous regenerative capacity, added to the deleterious remodelling programme set into motion by myocardial necrosis, turns MI into a progressively debilitating disease, which current pharmacological therapy cannot halt. The advent of Regenerative Therapies over 2 decades ago kick-started a whole new scientific field whose aim was to prevent or even reverse the pathological processes of MI. As a highly dynamic organ, the heart displays a tight association between 3D structure and function, with the non-cellular components, mainly the cardiac extracellular matrix (ECM), playing both fundamental active and passive roles. Tissue engineering aims to reproduce this tissue architecture and function in order to fabricate replicas able to mimic or even substitute damaged organs. Recent advances in cell reprogramming and refinement of methods for additive manufacturing have played a critical role in the development of clinically relevant engineered cardiovascular tissues. This review focuses on the generation of human cardiac tissues for therapy, paying special attention to human pluripotent stem cells and their derivatives. We provide a perspective on progress in regenerative medicine from the early stages of cell therapy to the present day, as well as an overview of cellular processes, materials and fabrication strategies currently under investigation. Finally, we summarise current clinical applications and reflect on the most urgent needs and gaps to be filled for efficient translation to the clinical arena.

Does Chronic Kidney Disease Facilitate Malignant Myocardial Fibrosis in Heart Failure with Preserved Ejection Fraction of Hypertensive Origin?

In hypertensive patients with heart failure (HF) a serum biomarker combination of high carboxy-terminal propeptide of procollagen type-I (PICP) and low carboxy-terminal telopeptide of collagen type-I to matrix metalloproteinase-1 (CITP:MMP-1) ratio identifies a histomolecular phenotype of malignant myocardial fibrosis (mMF) associated with severe diastolic dysfunction (DD) and poor outcomes. As chronic kidney disease (CKD) facilitates MF and DD, we investigated the influence of CKD on the mMF biomarker combination in HF patients with preserved ejection fraction (HFpEF). Hypertensives (n = 365), 232 non-HF and 133 HFpEF, were studied, and 35% non-HF and 46% HFpEF patients had CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2 or urine albumin-to-creatinine ratio ≥ 30 mg/g). Specific immunoassays were performed to determine biomarkers. Medians were used to establish the high PICP and low CITP:MMP-1 combination. A comparison with non-HF showed that the biomarker combination presence was increased in HFpEF patients, being associated with CKD in all patients. CKD influenced the association of the biomarker combination and HFpEF (p for interaction ≤ 0.019). The E:e' ratio was associated with the biomarker combination in CKD patients. Among CKD patients with HFpEF, those with the biomarker combination exhibited higher (p = 0.016) E:e' ratio than those without the pattern. These findings suggest that CKD facilitates the development of biomarker-assessed mMF and DD in hypertensive HFpEF patients.

Left ventricular pacing site in cardiac resynchronization therapy: clinical follow-up and predictors of failed lateral implant.

The effects of the left ventricular (LV) pacing site on the clinical results of resynchronization therapy (CRT) are not well characterized. The aim of this study was to define the effect of LV lead location on clinical response and LV remodelling, and to identify predictors of failure to implant the LV lead in a lateral location. One hundred and seventy two consecutive patients were evaluated at baseline and 6 months after CRT. In 128 patients, the LV lead was implanted in the lateral region (Group 1), while 44 received an anterior implant due to anatomical or electrical factors (Group 2). Group 1 was associated with a significantly better functional outcome assessed both by NYHA class (p<0.001) and by the six-minute-walk test (p=0.01) compared with group 2. LV ejection fraction and volumes, and inter- and intraventricular dyssynchrony only improved significantly (p<0.01) in group 1. The only independent predictor of a failed lateral implant was the presence of ischaemic cardiomyopathy (OR 3.29, 95% CI 2.2-13.7; p=0.02). In conclusion, a lateral lead location results in a better functional outcome and greater reverse LV remodelling compared with anterior locations. The presence of ischaemic cardiomyopathy is a risk factor for a failed lateral LV implant.

Transplantation of adipose derived stromal cells is associated with functional improvement in a rat model of chronic myocardial infarction.

AIMS: To determine the effect of transplantation of undifferentiated and cardiac pre-differentiated adipose stem cells compared with bone marrow mononuclear cells (BM-MNC) in a chronic model of myocardial infarction. METHODS: Ninety-five Sprague-Dawley rats underwent left coronary artery ligation and after 1 month received by direct intramyocardial injection either adipose derived stem cells (ADSC), cardiomyogenic cells (AD-CMG) or BM-MNC from enhanced-Green Fluorescent Protein (eGFP) mice. The control group was treated with culture medium. Heart function was assessed by echocardiography and 18F-FDG microPET. Cell engraftment, differentiation, angiogenesis and fibrosis in the scar tissue were also evaluated by (immuno)histochemistry and immunofluorescence. RESULTS: One month after cell transplantation, ADSC induced a significant improvement in heart function (LVEF 46.3+/-9.6% versus 27.7+/-8% pre-transplant) and tissue viability (64.78+/-7.2% versus 55.89+/-6.3% pre-transplant). An increase in the degree of angiogenesis and a decrease in fibrosis were also detected. Although transplantation of AD-CMG or BM-MNC also had a positive, albeit smaller, effect on angiogenesis and fibrosis in the infarcted hearts, this benefit did not translate into a significant improvement in heart function or tissue viability. CONCLUSION: These results indicate that transplantation of adipose derived cells in chronic infarct provides a superior benefit to cardiac pre-differentiated ADSC and BM-MNC.

A comparison between percutaneous and surgical transplantation of autologous skeletal myoblasts in a swine model of chronic myocardial infarction.

OBJECTIVE: Our aim was to compare the efficacy of surgical versus percutaneous administration of skeletal myoblasts (SkM) in a swine model of chronic myocardial infarction and to determine the mechanism(s) involved in their beneficial effect. METHODS: Two months after induction of myocardial infarction (MI), Goettingen miniature pigs underwent autologous SkM transplant either by direct surgical injection (n=6) or percutaneous access and intramyocardial delivery under fluoroscopic and echocardiographic guidance (n=6). Control animals received media alone (n=4). Functional analysis was performed by 2D echocardiography. Myoblast engraftment, in vivo cell differentiation, vessel formation, fibrosis, and the ratio between collagen type I/III deposition were analyzed in the infarct (IA) and non-infarct area (NIA) by immunohistochemistry. RESULTS: Animals received a median of 407.55+/-115x10(6) BrdU-labeled autologous SkM. Myoblast transplant was associated with a statistically significant increase in left ventricular ejection fraction (p<0.01), increased vasculogenesis and decreased fibrosis (p<0.05), and reduced collagen type I/III ratio in the IA and NIA areas as compared with control animals. No differences were found between groups receiving SkM by percutaneous or surgical access. CONCLUSIONS: Our results indicate that increased vasculogenesis and changes in matrix remodeling with decreased fibrosis are associated with the beneficial effect of SkM transplant in chronic MI. The equivalent benefit observed from surgical and percutaneous delivery has important clinical implications.

Benefit of tolvaptan in the management of hyponatraemia in patients with diuretic-refractory congestive heart failure: the SEMI-SEC project.

AIMS: Hyponatraemia is an electrolyte disorder that occurs in advanced congestive heart failure (HF) and worsens prognosis. We explored the usefulness of tolvaptan, which has shown promising results in the treatment of this condition. METHODS AND RESULTS: This study is based on a retrospective national registry (2011-15) of patients hospitalized with refractory HF and hyponatraemia who agreed to receive tolvaptan when standard treatment was ineffective. The benefit of tolvaptan was analysed according to the following criteria: normalization ([Na+] ≥ 135 mmol/L) or increased sodium levels [Na+] ≥ 4 mEq/L on completion of treatment, and increase in urine output by 300 or 500 mL at 48 h. Factors associated with tolvaptan benefit were explored. A total of 241 patients were included, 53.9% of whom had ejection fraction <40%. All patients received concomitant loop diuretics. Initial tolvaptan dose was 17.2 ± 6.1 mg, and end dose was 26.4 ± 23.2 mg (duration 7.8 ± 8.6 days). Serum sodium concentrations increased significantly at 24-48 h, from 126.5 ± 6.2 mEq/L at baseline to 134.1 ± 6.1 mEq/L at the end of treatment (P < 0.0001). Weight fell by ~5 kg before discharge (P < 0.0001) and urine output increased 1.3-fold (P < 0.0001). Normal sodium levels and/or increases of 500 mL in urine output were achieved by 90.8% of patients (35.7% achieved both) and 94.8% increased to [Na+] ≥ 4 mEq/L and/or +300 mL in urine output (54.4% both). CONCLUSIONS: An increase in sodium levels and/or improvement in urine output was observed in patients admitted for HF and refractory hyponatraemia under tolvaptan treatment. Tolvaptan may be useful in this setting, in which no effective proven alternatives are available.

Catheter-based Intramyocardial Injection of FGF1 or NRG1-loaded MPs Improves Cardiac Function in a Preclinical Model of Ischemia-Reperfusion.

Cardiovascular protein therapeutics such as neuregulin (NRG1) and acidic-fibroblast growth factor (FGF1) requires new formulation strategies that allow for sustained bioavailability of the drug in the infarcted myocardium. However, there is no FDA-approved injectable protein delivery platform due to translational concerns about biomaterial administration through cardiac catheters. We therefore sought to evaluate the efficacy of percutaneous intramyocardial injection of poly(lactic-co-glycolic acid) microparticles (MPs) loaded with NRG1 and FGF1 using the NOGA MYOSTAR injection catheter in a porcine model of ischemia-reperfusion. NRG1- and FGF1-loaded MPs were prepared using a multiple emulsion solvent-evaporation technique. Infarcted pigs were treated one week after ischemia-reperfusion with MPs containing NRG1, FGF1 or non-loaded MPs delivered via clinically-translatable percutaneous transendocardial-injection. Three months post-treatment, echocardiography indicated a significant improvement in systolic and diastolic cardiac function. Moreover, improvement in bipolar voltage and decrease in transmural infarct progression was demonstrated by electromechanical NOGA-mapping. Functional benefit was associated with an increase in myocardial vascularization and remodeling. These findings in a large animal model of ischemia-reperfusion demonstrate the feasibility and efficacy of using MPs as a delivery system for growth factors and provide strong evidence to move forward with clinical studies using therapeutic proteins combined with catheter-compatible biomaterials.

Neuregulin-1ß induces mature ventricular cardiac differentiation from induced pluripotent stem cells contributing to cardiac tissue repair.

Stem cell-derived cardiomyocytes (CMs) are often electrophysiologically immature and heterogeneous, which represents a major barrier to their in vitro and in vivo application. Therefore, the purpose of this study was to examine whether Neuregulin-1ß (NRG-1ß) treatment could enhance in vitro generation of mature "working-type" CMs from induced pluripotent stem (iPS) cells and assess the regenerative effects of these CMs on cardiac tissue after acute myocardial infarction (AMI). With that purpose, adult mouse fibroblast-derived iPS from α-MHC-GFP mice were derived and differentiated into CMs through NRG-1ß and/or dimethyl sulfoxide (DMSO) treatment. Cardiac specification and maturation of the iPS was analyzed by gene expression array, quantitative real-time polymerase chain reaction, immunofluorescence, electron microscopy, and patch-clamp techniques. In vivo, the iPS-derived CMs or culture medium control were injected into the peri-infarct region of hearts after coronary artery ligation, and functional and histology changes were assessed from 1 to 8 weeks post-transplantation. On differentiation, the iPS displayed early and robust in vitro cardiogenesis, expressing cardiac-specific genes and proteins. More importantly, electrophysiological studies demonstrated that a more mature ventricular-like cardiac phenotype was achieved when cells were treated with NRG-1ß and DMSO compared with DMSO alone. Furthermore, in vivo studies demonstrated that iPS-derived CMs were able to engraft and electromechanically couple to heart tissue, ultimately preserving cardiac function and inducing adequate heart tissue remodeling. In conclusion, we have demonstrated that combined treatment with NRG-1ß and DMSO leads to efficient differentiation of iPS into ventricular-like cardiac cells with a higher degree of maturation, which are capable of preserving cardiac function and tissue viability when transplanted into a mouse model of AMI.