Genotype FBN1/phenotype relationship in a cohort of patients with Marfan syndrome.

Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the fibrillin-1 (FBN1) gene, and cardiovascular involvement is the leading cause of mortality. We sought to examine the genotype/phenotype realtionship in 61 consecutive patients with a phenotype and genotype compatible with MFS. The FBN1 gene was analyzed by massive sequencing using a hybridization capture-based target enrichment custom panel. Forty-three different variants of FBN1 were identified, of which 17 have not been previously reported. The causal variants of MFS were grouped into mutations resulting in haploinsufficiency (HI group; 23 patients) and mutations producing a dominant-negative effect (DN group; 38 patients). Patient information was collected from electronic medical records and clinical evaluation. While no significant differences were found between the two groups, the HI group included more cases with aortic dissection and occurring at a younger age that the DN group (34.7% vs. 15.8%; p = 0.160). Irrespective of the mutation group, males presented with a higher probability of aortic involvement (4-fold higher risk than females) and aortic dissections events occurred at younger ages. Patients with DN variants carrying a cysteine substitution had a higher incidence of ectopia lentis.

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.

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.

Polymer Conjugation of Docosahexaenoic Acid Potentiates Cardioprotective Therapy in Preclinical Models of Myocardial Ischemia/Reperfusion Injury.

While coronary angioplasty represents an effective treatment option following acute myocardial infarction, the reperfusion of the occluded coronary artery can prompt ischemia-reperfusion (I/R) injury that significantly impacts patient outcomes. As ω-3 polyunsaturated fatty acids (PUFAs) have proven, yet limited cardioprotective abilities, an optimized polymer-conjugation approach is reported that improves PUFAs bioavailability to enhance cardioprotection and recovery in animal models of I/R-induced injury. Poly-l-glutamic acid (PGA) conjugation improves the solubility and stability of di-docosahexaenoic acid (diDHA) under physiological conditions and protects rat neonatal ventricular myocytes from I/R injury by reducing apoptosis, attenuating autophagy, inhibiting reactive oxygen species generation, and restoring mitochondrial membrane potential. Enhanced protective abilities are associated with optimized diDHA loading and evidence is provided for the inherent cardioprotective potential of PGA itself. Pretreatment with PGA-diDHA before reperfusion in a small animal I/R model provides for cardioprotection and limits area at risk (AAR). Furthermore, the preliminary findings suggest that PGA-diDHA administration in a swine I/R model may provide cardioprotection, limit edema and decrease AAR. Overall, the evaluation of PGA-diDHA in relevant preclinical models provides evidence for the potential of polymer-conjugated PUFAs in the mitigation of I/R injury associated with coronary angioplasty.

[Comparative study of functional and structural changes produced in a porcine model of acute and chronic heart attack]. / Estudio comparativo de los cambios funcionales y estructurales producidos en un modelo porcino de infarto de miocardio agudo y crónico.

INTRODUCTION AND OBJECTIVES: Animal models are a useful tool for the evaluation of disease mechanisms and also for technologies for diagnosis and treatment. In this study we performed a descriptive analysis of the functional and structural cardiac changes occurred as a result of acute coronary occlusion in pigs and its evolution during 5 weeks. METHODS: 19-Large White pigs, weighing 20kg, randomized into 3-experimental series were used. After sternotomy, anterior descending coronary artery was occluded. Duration of occlusion: Series 1 (n=6) 60min; series 2 (n=8) 90min; series 3 (n=5) 60min followed for 5 weeks. The following parameters where then analyzed: global cardiac function (ECG, left ventricular and atrium pressures, aortic flow and cardiac echocardiography), regional contractility, troponin T and CK-MB levels, macroscopic and histological analyzes. RESULTS: Coronary occlusion transiently altered the global cardiac function and produced increased cell damage markers, impaired regional contractility and produced histological changes. The increment of ischemic time (60 vs. 90min) increased infarct size (13.4±5.4% vs. 22.9±7.8 S1 S2%; P=.04). After 5 weeks, morphological remodelling changes were evident. In 79% of cases ischemia triggered ventricular fibrillation. CONCLUSION: The porcine open chest model of acute myocardial infarction and reperfusion is valid for studying the pathophysiology of coronary ischemia, allows direct analysis of regional myocardial function and is easily retrievable in the event of serious arrhythmias.

Sum of effects of myocardial ischemia followed by electrically induced tachycardia on myocardial function.

BACKGROUND: The alteration of contractile function after tachyarrhythmia ceases is influenced by the type of prior ischemia (acute coronary syndrome or ischemia inherent in a coronary revascularization procedure). We aimed to analyze cardiac dysfunction in an acute experimental model of supraphysiological heart rate preceded by different durations and types of ischemia. MATERIAL AND METHODS: Twenty-four pigs were included in: (S1) series of ventricular pacing; (S2, A and B) series with 10 or 20 min, respectively, of coronary occlusion previous to ventricular pacing; S3 with 20 brief, repeated ischemia/reperfusion processes prior to ventricular pacing and; (S4) control series. Overall cardiac function parameters and regional myocardial contractility at the apex and base of the left ventricle were recorded, as were oxidative stress markers (glutathione and lipid peroxide serum levels). Left ventricular pacing at 60% over baseline heart rate was performed for 2 h followed by 1 h of recovery. RESULTS: High ventricular pacing rates preceded by short, repeated periods of coronary ischemia/reperfusion resulted in worse impairment of overall cardiac and regional function that continued to be altered 1 h after tachycardia ceased. There was significant reduction of stroke volume (26.9 ± 5.3 basal vs. 16 ± 6.2 ml; p<0.05), LVP; dP/dt and LAD flow (13.1 ± 1.5 basal vs. 8.4 ± 1.6 ml/min; p<0.05); the base contractility remained altered when recovering compared to baseline (base SF: 5.6 ± 2.8 vs. 2.2 ± 0.7%; p<0.05); and LPO levels were higher than less aggressive series at the end of recovery. CONCLUSIONS: Ischemia and tachycardia accumulate their effects, with increased cardiac involvement depending on the type of ischemia.

Effect of short-duration electrically induced tachycardia on regional myocardial contractility.

BACKGROUND: Tachycardia is a physiological mechanism for adapting cardiac output to modifications in energy consumption in the organism. The repercussions that short-duration tachycardia has on myocardial contractility have not been sufficiently studied.
To study the effects of short-duration tachycardia on regional myocardial function in the anterior face of the left ventricle depending on the rate, duration, and origin of the electrical stimulation producing the tachycardia. MATERIAL/METHODS: Two series were studied in an in vivo canine experimental model. Stimulation was performed in the right atrium and in the base of the left ventricle at a frequency 20 and 40% above the basal rate. The duration of each pacing episode was 10, 20, and 40 minutes followed by a recovery period of 40 minutes. ECG, left ventricular pressure, and regional function curves of a myocardial segment were studied. RESULTS: During atrial pacing there was a similar decrease in both regional segment lengths (end-systolic and end-diastolic lengths) and no variation in the shortening fraction or in hemodynamic parameters. During ventricular pacing, systolic pressure in the left ventricle decreased, end-diastolic pressure increased, end-diastolic length shortened (meaning less ventricular filling), and the end-systolic length increased, leading to a reduced shortening fraction or regional contractility alteration which was temporarily maintained once pacing ceased. CONCLUSIONS: The transient persistence of segment dysfunction after induced ventricular tachycardia ceases indicates the activation of a different, unknown mechanism.

La troponina T como posible marcador del daño miocárdico menor. su aplicación en el miocardio aturdido y en la isquemia silente / Troponine T as Possible Myocardial Injury Marker. Its Application in Myocardial Stunning and Silent Ischemia

Introducción y objetivos. La necesidad de disponer de marcadores bioquímicos más precoces y de mayor especificidad y sensibilidad para la detección del infarto agudo de miocardio ha impulsado la continua evaluación de métodos alternativos a la isoenzima MB de la creatincinasa (CK-MB). Nuestro objetivo ha sido conocer la utilidad de las determinaciones de la troponina T (TnT), frente a otros marcadores, para detectar procesos de isquemia transitoria en ausencia de necrosis. Métodos. Se ha utilizado un modelo canino experimental de isquemias muy breves y repetidas (series I y II), y un modelo de isquemia única de 15 min de duración, y 60 min de reperfusión (serie III). En la serie I el oclusor coronario se situó en la zona proximal de la arteria coronaria descendente anterior (DA), y en las series II y III en la zona distal de la DA. Las muestras de plasma se han obtenido de sangre venosa periférica (SVP) y coronaria (SVC), en distintas fases del estudio. Las concentraciones de adenosina, TnT, CK y CK-MB se determinaron por procedimientos bioquímicos. Se estudiaron los parámetros de función regional y general, y se realizó un estudio anatomopatológico para conocer el tamaño del área de riesgo. Resultados. En la serie I se produjo hipocinesia que persistió 10 días, y en las series II y III la función regional se había recuperado a las 24 h. Las concentraciones de CK y CK-MB aumentaron ya significativamente tras la apertura del tórax (p < 0,05) en las tres series, alcanzando el máximo valor a las 24 h del protocolo isquémico. La adenosina se elevó significativamente sólo tras la isquemia (p < 0,05). Los valores de TnT se elevaron con la isquemia hasta los 5 días en las tres series en SVP. No hubo correlación entre la función regional del miocardio aturdido y el incremento de troponina T. Conclusiones. La troponina T se eleva en ausencia de necrosis, preferentemente cuando los episodios isquémicos son prolongados (AU)