Extracellular vesicles fail to trigger the generation of new cardiomyocytes in chronically infarcted hearts.

Background: Extracellular vesicles (EV) mediate the therapeutic effects of stem cells but it is unclear whether this involves cardiac regeneration mediated by endogenous cardiomyocyte proliferation. Methods: Bi-transgenic MerCreMer/ZEG (n = 15/group) and Mosaic Analysis With Double Markers (MADM; n = 6/group) mouse models underwent permanent coronary artery ligation and received, 3 weeks later, 10 billion EV (from human iPS-derived cardiovascular progenitor cells [CPC]), or saline, injected percutaneously under echo guidance in the peri-infarcted myocardium. Endogenous cardiomyocyte proliferation was tracked by EdU labeling and biphoton microscopy. Other end points, including cardiac function (echocardiography and MRI), histology and transcriptomics were blindly assessed 4-6 weeks after injections. Results: There was no proliferation of cardiomyocytes in either transgenic mouse strains. Nevertheless, EV improved cardiac function in both models. In MerCreMer/ZEG mice, LVEF increased by 18.3 ± 0.2% between baseline and the end-study time point in EV-treated hearts which contrasted with a decrease by 2.3 ± 0.2% in the PBS group; MADM mice featured a similar pattern as intra-myocardial administration of EV improved LVEF by 13.3 ± 0.16% from baseline whereas it decreased by 14.4 ± 0.16% in the control PBS-injected group. This functional improvement was confirmed by MRI and associated with a reduction in infarct size, the decreased expression of several pro-fibrotic genes and an overexpression of the anti-fibrotic miRNA 133-a1 compared to controls. Experiments with an anti-miR133-a demonstrated that the cardio-reparative effects of EV were partly abrogated. Conclusions: EV-CPC do not trigger cardiomyocyte proliferation but still improve cardiac function by other mechanisms which may include the regulation of fibrosis.

Progression of Carcinoid Heart Disease in the Modern Management Era.

Background The development of carcinoid heart disease (CaHD) is still relatively unclear. It is difficult to define an optimal follow-up for patients without any cardiac involvement at baseline. The aim of this study was to assess the prevalence and natural history of CaHD by annual echocardiographic examinations. Methods and Results We studied 137 consecutive patients (61±12 years, 53% men) with proven digestive endocrine tumor and carcinoid syndrome between 1997 and 2017. All patients underwent serial conventional transthoracic echocardiographic studies. Right-sided and left-sided CaHD were systematically assessed. We used a previous validated echocardiographic scoring system of severity for the assessment of CaHD. An increase of 25% of the score was considered to be significant. Mean follow-up was 54±45 months. Prevalence of CaHD was 27% at baseline and 32% at 5-year follow-up. Disease progression was reported in 28% of patients with initial CaHD followed up for >2 years (n=25). In patients without any cardiac involvement at baseline, occurrence of disease was 21%. CaHD occurred >5 years from the initial echocardiographic examination in 42% of our cases, especially in patients presenting with new recurrence of a digestive endocrine tumor. An increase of urinary 5-hydroxyindoleacetic acid by 25% during follow-up was identified as an independent predictor of CaHD occurrence during follow-up (hazard ratio [HR], 5.81; 95% CI, 1.19-28.38; P=0.03), as well as a maximum value of urinary 5-hydroxyindoleacetic acid >205 mg/24 h during follow-up (HR, 8.41; 95% CI, 1.64-43.07; P=0.01). Conclusions Our study demonstrates that in patients without initial CaHD, cardiac involvement may occur late and is related to serotonin. Our data emphasize the need for cardiologic follow-up in patients with recurrence of the tumor process.

Management and outcomes of hypertrophic cardiomyopathy in young adults.

BACKGROUND: Management of young adults with hypertrophic cardiomyopathy (HCM) is challenging. AIMS: To evaluate the profile of young adults (16-25 years) with HCM included in the French prospective HCM registry. METHODS: Patients were compared according to occurrence of major adverse cardiac events (MACE), comprising sudden cardiac death (SCD) events (implantable cardioverter defibrillator [ICD] discharge, SCD, sustained ventricular tachycardia), atrial fibrillation/embolic stroke, heart failure hospitalisation and unexplained syncope, at a mean follow-up of 4.4±2.2 years. RESULTS: At baseline, among 61 patients (20.5±3.0 years; 16 women, 26.2%), 13 (21.3%) had a prophylactic ICD, 24.6% a family history of SCD, 29.5% obstruction, 86.0% magnetic resonance imaging myocardial fibrosis, 11.8% abnormal exercise blood pressure and 52.8% a European Society of Cardiology (ESC) 5-year SCD score<4% (24.5%≥6%). At follow-up, 15 patients (24.6%; seven women; all with fibrosis) presented 17 MACE, comprising: SCD events (n=7, 41.2%; including three patients with an ICD, five with at least one SCD major classical risk factor and an ESC score≥5% and two with no risk factors and an ESC score<4%); atrial fibrillation/stroke (n=6, 35.3%); heart failure (n=1, 5.9%); syncope (n=3, 17.6%). An ICD was implanted in 11 patients (four for secondary prevention), but in only 61.5% of patients with a score≥6%. Only obstruction significantly increased MACE risk (odds ratio 3.96; P=0.035), with a non-significant trend towards a lower risk in men (OR 0.29; P=0.065). CONCLUSIONS: In young adults with HCM, MACE are common in the short term, especially in obstructive HCM and women, mostly arrhythmic in origin. Prophylactic ICD implantation is frequent and does not strictly follow the guidelines, while the use of European/USA guidelines is helpful but imperfect in identifying SCD risk.