Modeling Cardiotoxicity in Pediatric Oncology Patients Using Patient-Specific iPSC-Derived Cardiomyocytes Reveals Downregulation of Cardioprotective microRNAs.

Anthracyclines are widely used in the treatment of many solid cancers, but their efficacy is limited by cardiotoxicity. As the number of pediatric cancer survivors continues to rise, there has been a concomitant increase in people living with anthracycline-induced cardiotoxicity. Accordingly, there is an ongoing need for new models to better understand the pathophysiological mechanisms of anthracycline-induced cardiac damage. Here we generated induced pluripotent stem cells (iPSCs) from two pediatric oncology patients with acute cardiotoxicity induced by anthracyclines and differentiated them to ventricular cardiomyocytes (hiPSC-CMs). Comparative analysis of these cells (CTX hiPSC-CMs) and control hiPSC-CMs revealed that the former were significantly more sensitive to cell injury and death from the anthracycline doxorubicin (DOX), as measured by viability analysis, cleaved caspase 3 expression, oxidative stress, genomic and mitochondrial damage and sarcomeric disorganization. The expression of several mRNAs involved in structural integrity and inflammatory response were also differentially affected by DOX. Functionally, optical mapping analysis revealed higher arrythmia complexity after DOX treatment in CTX iPSC-CMs. Finally, using a panel of previously identified microRNAs associated with cardioprotection, we identified lower levels of miR-22-3p, miR-30b-5p, miR-90b-3p and miR-4732-3p in CTX iPSC-CMs under basal conditions. Our study provides valuable phenotype information for cellular models of cardiotoxicity and highlights the significance of using patient-derived cardiomyocytes for studying the associated pathogenic mechanisms.

MicroRNA-4732-3p Is Dysregulated in Breast Cancer Patients with Cardiotoxicity, and Its Therapeutic Delivery Protects the Heart from Doxorubicin-Induced Oxidative Stress in Rats.

Anthracycline-induced cardiotoxicity is the most severe collateral effect of chemotherapy originated by an excess of oxidative stress in cardiomyocytes that leads to cardiac dysfunction. We assessed clinical data from patients with breast cancer receiving anthracyclines and searched for discriminating microRNAs between patients that developed cardiotoxicity (cases) and those that did not (controls), using RNA sequencing and regression analysis. Serum levels of 25 microRNAs were differentially expressed in cases versus controls within the first year after anthracycline treatment, as assessed by three different regression models (elastic net, Robinson and Smyth exact negative binomial test and random forest). MiR-4732-3p was the only microRNA identified in all regression models and was downregulated in patients that experienced cardiotoxicity. MiR-4732-3p was also present in neonatal rat cardiomyocytes and cardiac fibroblasts and was modulated by anthracycline treatment. A miR-4732-3p mimic was cardioprotective in cardiac and fibroblast cultures, following doxorubicin challenge, in terms of cell viability and ROS levels. Notably, administration of the miR-4732-3p mimic in doxorubicin-treated rats preserved cardiac function, normalized weight loss, induced angiogenesis, and decreased apoptosis, interstitial fibrosis and cardiac myofibroblasts. At the molecular level, miR-4732-3p regulated genes of TGFß and Hippo signaling pathways. Overall, the results indicate that miR-4732-3p is a novel biomarker of cardiotoxicity that has therapeutic potential against anthracycline-induced heart damage.

miR-4732-3p in Extracellular Vesicles From Mesenchymal Stromal Cells Is Cardioprotective During Myocardial Ischemia.

Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) are an emerging alternative to cell-based therapies to treat many diseases. However, the complexity of producing homogeneous populations of EVs in sufficient amount hampers their clinical use. To address these limitations, we immortalized dental pulp-derived MSC using a human telomerase lentiviral vector and investigated the cardioprotective potential of a hypoxia-regulated EV-derived cargo microRNA, miR-4732-3p. We tested the compared the capacity of a synthetic miR-4732-3p mimic with EVs to confer protection to cardiomyocytes, fibroblasts and endothelial cells against oxygen-glucose deprivation (OGD). Results showed that OGD-induced cardiomyocytes treated with either EVs or miR-4732-3p showed prolonged spontaneous beating, lowered ROS levels, and less apoptosis. Transfection of the miR-4732-3p mimic was more effective than EVs in stimulating angiogenesis in vitro and in vivo and in reducing fibroblast differentiation upon transforming growth factor beta treatment. Finally, the miR-4732-3p mimic reduced scar tissue and preserved cardiac function when transplanted intramyocardially in infarcted nude rats. Overall, these results indicate that miR-4732-3p is regulated by hypoxia and exerts cardioprotective actions against ischemic insult, with potential application in cell-free-based therapeutic strategies.

Effects of Cardiopulmonary Rehabilitation on the Muscle Function of Children with Congenital Heart Disease: A Prospective Cohort Study.

Critical medical and surgical advances have led to a shift in the care and management of children with congenital heart disease (CHD). These patients present with muscle deconditioning, which negatively influences their response to exercise, functional capacities, and quality of life. This study evaluates the influence of a cardiopulmonary rehabilitation program (CPRP) on the function of peripheral musculature of children with CHD. A single-center prospective cohort study was designed. Fifteen CHD subjects, between 12 and 16 years of age, with reduced aerobic capacity on a cardiopulmonary exercise test, were included in a three-month, 24-session CPRP. Measurements of the subjects' handgrip strength, biceps brachii and quadriceps femoris strength, and triceps surae fatigue process were collected at the beginning of the program, after completion, and six months after the end of the intervention. A substantial and statistically significant improvement was observed in the subjects' handgrip strength (kg) (p < 0.001), biceps brachii and quadriceps femoris strength (N) (p < 0.001), as well as triceps surae fatigue process (repetitions) (p = 0.018), with a maintenance of the results six months after the intervention. These results suggest that a CPRP could potentially improve the peripheral muscle function of children with CHD. Additional research is needed to confirm and expand on this hypothesis.

Cardiopulmonary Rehabilitation Improves Respiratory Muscle Function and Functional Capacity in Children with Congenital Heart Disease. A Prospective Cohort Study.

Critical surgical and medical advances have shifted the focus of congenital heart disease (CHD) patients from survival to achievement of a greater health-related quality of life (HRQoL). HRQoL is influenced, amongst other factors, by aerobic capacity and respiratory muscle strength, both of which are reduced in CHD patients. This study evaluates the influence of a cardiopulmonary rehabilitation program (CPRP) on respiratory muscle strength and functional capacity. Fifteen CHD patients, ages 12 to 16, with reduced aerobic capacity in cardiopulmonary exercise testing (CPET) were enrolled in a CPRP involving strength and aerobic training for three months. Measurements for comparison were obtained at the start, end, and six months after the CPRP. A significant improvement of inspiratory muscle strength was evidenced (maximum inspiratory pressure 21 cm H2O, 23%, p < 0.01). The six-minute walking test showed a statistically and clinically significant rise in walked distance (48 m, p < 0.01) and a reduction in muscle fatigue (1.7 out of 10 points, p = 0.017). These results suggest CPRP could potentially improve respiratory muscle function and functional capacity, with lasting results, in children with congenital heart disease, but additional clinical trials must be conducted to confirm this finding.

«Preparo Mi Rotación Por», complemento virtual de la formación MIR en Pediatría / «I Prepare My Rotation By», a virtual complement of paediatric specialist training

La Asociación Española de Pediatría (AEP) tiene entre sus objetivos desarrollar actividades encaminadas a la formación de sus socios. Así, en 2013 puso en marcha su proyecto formativo más ambicioso, la plataforma de formación virtual «Continuum». Se presenta ahora una nueva sección dirigida a los médicos internos residentes (MIR) en Pediatría y a sus tutores: «Preparo Mi Rotación Por» (PMRP), que tiene como propósitos disminuir la variabilidad en la formación de los MIR, asistir a los tutores en su función docente, facilitar el aprendizaje colaborativo y basado en competencias, el entrenamiento reflexivo y la resolución de problemas propios del perfil profesional de cada especialidad pediátrica. PMRP se distribuye en tres secciones principales: «De dónde partimos» (con las subsecciones: cuestionario de autoevaluación y contrato de aprendizaje), «Situaciones a resolver» (donde se desglosan los escenarios clínicos que han sido escogidos en el contrato de aprendizaje) y «A dónde llegamos» (que vuelve a incluir las subsecciones del comienzo de la rotación, para comprobar si los objetivos previstos han sido alcanzados, y el informe de evaluación). Además, cuenta con otros recursos: conocimientos previos, porfolio y foro de debate. Cabe destacar cinco aspectos del modelo formativo propuesto en esta nueva sección: el escenario clínico como punto de partida; el aprendizaje basado en competencias (fundamentado en el Global Pediatric Educational Consortium); la evaluación como estímulo de formación; el poder del aprendizaje colaborativo, y la participación de las diferentes sociedades de especialidad de la AEP en el desarrollo de sus contenidos

The Spanish Paediatric Association (AEP) has, among its objectives, to develop activities aimed at the training of its members. Thus, in 2013, it began its most ambitious training project, the virtual platform, «Continuum». Now it presents a new section aimed at Internal Medicine Residents (MIR) in Paediatrics and their tutors: «I Prepare My Rotation By» (PMRP), which has as objectives to reduce the variation in MIR training, to help the tutors in their teaching function, to facilitate collaborative and skill-based learning, reflective training, and the resolving of the particular problems of the professional profile of each paediatric speciality. PMRP is split into three main sections: «From where do we start» (with the sub-sections: self-assessment questionnaire and learning agreement), «Situations to resolve» (where the clinical scenarios that have been selected in the learning agreement are broken down), and «To where have we got» (which includes again the sub-sections at the beginning of the rotation in order to check if the expected objectives have been reached, and the assessment report). It also has other resources: prior knowledge, portfolio, and discussion forum. Five features of the proposed training model should be highlighted: the clinical scenario as a starting point; skill-based learning (based on the Global Paediatric Educational Consortium); the assessment as a training stimulus; the power of collaborative learning, and the participation of the different specialist societies of the AEP in the development of its contents

[«I Prepare My Rotation By¼, a virtual complement of paediatric specialist training]. / «Preparo Mi Rotación Por¼, complemento virtual de la formación MIR en Pediatría.

The Spanish Paediatric Association (AEP) has, among its objectives, to develop activities aimed at the training of its members. Thus, in 2013, it began its most ambitious training project, the virtual platform, «Continuum¼. Now it presents a new section aimed at Internal Medicine Residents (MIR) in Paediatrics and their tutors: «I Prepare My Rotation By¼ (PMRP), which has as objectives to reduce the variation in MIR training, to help the tutors in their teaching function, to facilitate collaborative and skill-based learning, reflective training, and the resolving of the particular problems of the professional profile of each paediatric speciality. PMRP is split into three main sections: «From where do we start¼ (with the sub-sections: self-assessment questionnaire and learning agreement), «Situations to resolve¼ (where the clinical scenarios that have been selected in the learning agreement are broken down), and «To where have we got¼ (which includes again the sub-sections at the beginning of the rotation in order to check if the expected objectives have been reached, and the assessment report). It also has other resources: prior knowledge, portfolio, and discussion forum. Five features of the proposed training model should be highlighted: the clinical scenario as a starting point; skill-based learning (based on the Global Paediatric Educational Consortium); the assessment as a training stimulus; the power of collaborative learning, and the participation of the different specialist societies of the AEP in the development of its contents.

Extracellular Vesicles Secreted by Hypoxic AC10 Cardiomyocytes Modulate Fibroblast Cell Motility.

Extracellular vesicles (EVs) are small membrane vesicles secreted by most cell types with important roles in cell-to-cell communication. To assess their relevance in the context of heart ischemia, EVs isolated from the AC10 ventricular cardiomyocyte cell line (CM-EVs), exposed to normoxia (Nx) or hypoxia (Hx), were incubated with fibroblasts (Fb) and endothelial cells (EC). CM-EVs were studied using electron microscopy, nanoparticle tracking analysis (NTA), western blotting and proteomic analysis. Results showed that EVs had a strong preference to be internalized by EC over fibroblasts, suggesting an active exosome-based communication mechanism between CM and EC in the heart. In Matrigel tube-formation assays, Hx CM-EVs were inferior to Nx CM-EVs in angiogenesis. By contrast, in a wound-healing assay, wound closure was faster in fibroblasts treated with Hx CM-EVs than with Nx CM-EVs, supporting a pro-fibrotic effect of Hx CM-EVs. Overall, these observations were consistent with the different protein cargoes detected by proteomic analysis under Nx and Hx conditions and the biological pathways identified. The paracrine crosstalk between CM-EVs, Fb, and EC in different physiological conditions could account for the contribution of CM-EVs to cardiac remodeling after an ischemic insult.

Aneurisma del ductus arterioso: diagnóstico prenatal y evolución / Ductus arteriosus aneurysm: Prenatal diagnosis and outcome

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