Enzima convertidora de angiotensina homóloga (ECA2) y actividad de ROCK en la falla cardíaca experimental / ACE 2 and ROCK activity in experimental congestive heart failure

Antecedentes: La ECA2 ha mostrado ser un regulador esencial de la funcionalidad cardíaca. En un modelo experimental de insuficiencia cardíaca (IC) con Fier, modelo de coartación de aorta (COA), se encontró activación de la vía Rho-kinasa. La inhibición de esta vía con fasudil no mejoró el remodelado cardíaco ni la disfunción sistólica. Se desconoce en este modelo, si el deterioro de la función cardíaca y activación de la vía rho-kinasa se asocia con una disminución de la ECA2 cardíaca y si la inhibición de Rho-kinasa tiene un efecto sobre la expresión de ECA2. Objetivo: Nuestro objetivo es determinar si en la falla cardaca experimental por coartación aórtica, los niveles proteicos de ECA2 en el miocardio se asocian a disfunción sistólica y cual es su interacción con la actividad de ROCK en el miocardio. Métodos: Ratones C57BL6J machos de 7-8 semanas se randomizaron en 3 grupos experimentales. Grupo COA por anudación de la aorta + vehículo; Grupo COA + Fasudil (100 mg/Kg día) por bomba osmótica desde la semana 5 post-cirugía; y grupo control o Sham. Se determinaron las dimensiones y función cardíaca por ecocardiografía. Posterior a la eutanasia, se determinaron los niveles de ECA2 del VI por Western-blot y actividad de la Rho-kinasa Resultados: En los grupos COA+vehículo y COA-FAS hubo deterioro de la función cardíaca, reflejada por la reducción de la FE (47,9 ± 1,53 y 45,5 ± 2,10, p < 0,05, respectivamente) versus SHAM (68,6 ± 1,19). Además, aumentaron las dimensiones cardíacas y hubo desarrollo de hipertrofia (0,53 ± 0,02 / 0,53 ± 0,01, p < 0,05) medida por aumento de la masa cardíaca relativa respecto del grupo SHAM (0,40 ± 0,01). En los grupos COA+vehículo y COA-FAS se encontró una disminución significativa del 35% en la expresión de ECA2 cardíaca respecto al grupo control. Conclusiones: La disfunción sistólica por coartación aórtica se asocia con aumento de la actividad de Rho-kinasa y significativa disminución de la expresión de ECA2. La inhibición de Rho-kinasa no mejoró el remodelado cardíaco, la disfunción sistólica y tampoco modificó los niveles de ECA2 cardíaca.

Background: ACE2 has been described as an essential regulator of cardiac function. In an experimental model of heart failure (HF) and heart failure reduced ejection fraction (HFrEF), the aortic coarctation (COA) model, activation of the Rho-kinase pathway of cardiac remodeling was found. Inhibition of this pathway did not improve cardiac remodeling or systolic ventricular dysfunction. It is unknown in this model whether the impairment of cardiac function and activation of the rho-kinase pathway is associated with a decrease in ACE2 and whether rho-kinase inhibition has an effect on ACE2 expression. Objective: To determine if in experimental heart failure due to aortic coarctation, ACE2 protein levels in the myocardium are associated with systolic dysfunction and what is its interaction with ROCK activity in the myocardium. Methods: Male C57BL6J mice aged 7-8 weeks were divided into 3 groups and anesthetized: One group underwent COA+ vehicle; A second group COA + Fasudil (100 mg/Kg/d) by osmotic pump from week 5 post-surgery and; the third group, control(SHAM). Echocardiograms were performed to determine cardiac dimensions and systolic function. Rats were then euthanized. Ventricular expression of ACE2, activity of the Rho-kinase pathway by MYPT-1 phosphorylation, relative cardiac mass, area and perimeter of cardiomyocytes were determined by Western blot. Results: In both COA+vehicle and COA+FAS groups there was deterioration of cardiac function, reflected in the reduction of EF (47.9 ± 1.53 and 45.5 ± 2.10, p < 0.05, respectively) versus the SHAM group (68.6 ± 1.19). In addition, cardiac dimensions and hypertrophy increased (0.53 ± 0.02 / 0.53 ± 0.01, p < 0.05) due to increased relative cardiac mass compared to the SHAM group (0.40 ± 0.01). In the COA+vehicle and COA+FAS groups a significant decrease of 35% in cardiac ACE2 expression was found compared to the control group. Conclusions: Systolic dysfunction due to aortic coarctation is associated with increased Rhokinase activity and a significant decrease in ACE2 expression. Rho-kinase inhibition did not improve cardiac remodeling, systolic dysfunction, nor did it change cardiac ACE2 levels.

Antihipertensivos en pacientes con COVID-19 / Anti hypertensive agents in patients with COVID-19

En 31 de diciembre del 2019 la Organización Mundial de la Salud fue informada por las autoridades sanitarias chinas de la aparición de casos de neumonía de origen desconocido en la ciudad de Wuhan en China. El 7 de Enero de 2020, científicos chinos identificaron a un nuevo coronavirus (temporalmente designado como "2019-nCoV") como el agente etiológico de la enfermedad denominada COVID-19. La secuenciación del genoma del nuevo coronavirus mostró gran similitud con el coronavirus (Covid-1 o SARS-CoV) causante del síndrome respiratorio agudo severo (SARS), ocurrido también en China entre los años 2002-2003. Por este motivo, 2019-nCoV se rebautizó como SARS-CoV-2 (Severe Acute Respiratory Syndrome Corona Virus-2) y a la fecha es responsable de la actual y grave pandemia que está ocasionando impactos sanitarios y socio-económicos a escala global. Las investigaciones con SARS-CoV establecieron que este virus ingresa a nuestras células utilizando como receptor a la enzima convertidora de angiotensina tipo 2 (ECA 2 o en inglés ACE-2: "angiotensin converting enzyme type 2"). Dado este antecedente también se confirmó que SARS-CoV-2 también utiliza esta misma enzima ya que no se habla de un mecanismo en si para ingresar a sus células blanco, especialmente a nivel de nuestro sistema respiratorio. ECA-2 es una proteasa integrante del sistema renina angiotensina "alterno o no canónico" con importantes acciones regulatorias sobre los sistemas cardiovascular, renal y pulmonar, entre otros. En este contexto, ha surgido preocupación tanto por clínicos como los propios pacientes respecto al estado de pacientes hipertensos con COVID-19 y su vulnerabilidad a infectarse con SARS-CoV-2 dado que algunos trabajos han planteado que ciertos polimorfismos en el gen ECA-2 asociados a hipertensión arterial podrían determinar una mayor expresión de ECA-2. Además, estudios preclínicos han sugerido que ciertos fármacos antihipertensivos (principalmente, inhibidores de ECA y antagonistas del receptor para angiotensina II subtipo 1) también podrían estimular una mayor expresión de ECA-2. Esta revisión tiene por objetivo presentar y discutir los antecedentes en el estado del arte respecto a esta reciente problemática. El análisis crítico de los presentes antecedentes permite concluir que no existe evidencia clínica sólida que permita afirmar que el uso de medicamentos antihipertensivos genere una mayor vulnerabilidad a la infección con SARS-CoV-2. Por lo tanto no se debe descontinuar su uso en pacientes hipertensos en riesgo de infección a SARS-CoV-2 o que padezcan COVID-19.

In December 2019, a new type of coronavirus emerged in the city of Wuhan, China. This novel virus has unleashed a pandemic that has inflicted a considerable impact on public health and the economy and has therefore become a severe concern worldwide. This new virus -named SARS-CoV-2has been rapidly investigated in order to create knowledge aimed at achieving its control. Comparative studies with SARS-CoV virus, responsible for the 2002-2003 pandemic, suggest that SARS-CoV-2 requires the same receptor to bind and infect cells: angiotensin converting enzyme 2 (ACE-2). This hypothesis has been thoroughly supported by a variety of in vitro research and is currently considered a potential therapeutic target. ACE-2 is part of the counter-regulatory renin-angiotensin system, exerting effects in pulmonary, renal and cardiovascular systems. In this context, concerns have arisen in regards to the vulnerability of hypertensive patients against COVID-19, given that there is evidence that may suggest that polymorphisms associated to hypertension may increase the expression of ACE-2. Moreover, preclinical studies have shown that antihypertensive drugs may increase the expression of this enzyme. In this review article, we present the current state of the art on this polemic topic. Our critical analysis suggest that there is no robust clinical evidence supporting the hypothesis that the use of antihypertensive drugs can increase vulnerability to infection with SARS-CoV-2. Therefore, we recommend that the use of these therapeutic agents should not be discontinued in hypertensive patients in risk to or suffering COVID-19.

Remodelado cardíaco en el modelo preclínico de falla cardíaca isquémica experimental por dislipidemia en el ratón SR-B1 KO/ApoER6 1h/h / Cardiac remodeling in experimental cardiac failure induced by hyperlipidemia in mice

INTRODUCCIÓN: Los ratones SR-B1 KO/ApoER6 1h/h que son alimentados con una dieta rica en grasas saturadas, desarrollan enfermedad coronaria aterosclerótica severa, complicaciones isquémicas e insuficiencia cardíaca, con alta mortalidad. Los estudios con este modelo se han enfocado fundamentalmente en la enfermedad coronaria y menos en el remodelado cardíaco. El OBJETIVO del trabajo ha sido caracterizar el remodelado miocárdico, evaluar la evolución temporal de la función ventricular izquierda y la sobrevida asociada a enfermedad cardíaca por ateromatosis. MÉTODO: Ratones homocigotos SR-B1 KO/ApoER6 1h/h fueron alimentados por 8 semanas con dieta aterogénica o dieta normal y se comparó la sobrevida en ambos grupos. A las 4 semanas se realizó un ecocardiograma bidimensional. En los ratones eutanasiados se evaluó en la pared cardíaca fibrosis miocárdica y tamaño de los cardiomiocitos por morfometría, apoptosis con técnica de TUNEL e infiltración por células inflamatorias mononucleares (ED1) por inmunohistoquímica. RESULTADOS: En el grupo que recibió dieta aterogénica la sobrevida se redujo en 46,7% (p < 0.001), debido a muerte súbita y a falla cardíaca progresiva. En este grupo, a las 4 semanas se observó dilatación de cavidades izquierdas y disminución de la fracción de eyección del ventrículo izquierdo en comparación con el grupo control (79,3 ± 1,3% vs 66 ± 3,7%, p<0,01). También se observó aumento de la masa cardíaca relativa de 2.1 veces (p<0,001) y del peso pulmonar relativo en 80% (p<0,001), sin cambios en las dimensiones de los cardiomiocitos. En el miocardio de los ratones que recibieron dieta aterogénica hubo un aumento de la fibrosis cardíaca de 7.9 veces (p < 0.01) y del número de cardiomiocitos apoptóticos en 55.9 veces (p < 0.01), junto a un aumento del número de células inflamatorias mononucleares ED1. CONCLUSIONES: En el modelo de falla cardíaca severa de etiología isquémica con alta mortalidad en el ratón homocigoto SR-B1 KO/ApoER6 1h/h sometido a una dieta aterogénica, con falla cardíaca izquierda por disfunción sistólica, el remodelado patológico del miocardio está dado fundamentalmente por apoptosis y fibrosis. También se observa un aumento discreto de macrófagos en la pared cardíaca. Es posible que el edema parietal también pueda ser un mecanismo de remodelado relevante en este modelo.

Abstract: SR-B1 KO/ApoER6 1h/h mice fed a high saturated fat diet develop severe coronary atheromatosis, and cardiac failure with a high mortality rate. Cardiac remodeling under these conditions has not been well studied. AIM: To evaluate the time course of left ventricular function, cardiac remodeling and survival associated to the administration of an atherogenic diet. METHOD: Homozygote SR-B1 KO/ApoER6 1h/h mice received an atherogenic diet for 8 weeks. Mice receiving a normal diet served as controls. Survival rate, myocardial fibrosis, cardiomyocyte size, apoptosis and infiltration by inflammatory or mononuclear cells were compared between groups. A TUNEL technique was used to evaluate apoptosis. RESULTS: A 46.7% survival reduction compared to controls was observed in the experimental group (p<0.01), due to left ventricular and atrial dilatation associated to a decrease in ejection fraction (79,3 ± 1,3% vs 66 ± 3,7%, p<0,01, respectively). Also, an increased cardiac weight, 2.6 times greater was observed in the experimental group, compared to controls. Mice receiving the atherogenic diet showed an 80% increased lung weight. There was no evident change in cardiomyocytes, but there was more (7.9 times) cardiac fibrosis (p<0.01) and 55.9 times more apoptotic cells. (p<0.01), along with a greater number of inflammatory cells and ED1 mononuclear cells. CONCLUSION: Mice receiving an atherogenic diet develop heart failure and reduced survival rate. This is associated with cardiac remodeling with underlying apoptosis an ventricular wall fibrosis. It is posible that wall edema might contribute to the observed cardiac remodeling.

Angiotensin-(1-9) prevents cardiomyocyte hypertrophy by controlling mitochondrial dynamics via miR-129-3p/PKIA pathway.

Angiotensin-(1-9) is a peptide from the noncanonical renin-angiotensin system with anti-hypertrophic effects in cardiomyocytes via an unknown mechanism. In the present study we aimed to elucidate it, basing us initially on previous work from our group and colleagues who proved a relationship between disturbances in mitochondrial morphology and calcium handling, associated with the setting of cardiac hypertrophy. Our first finding was that angiotensin-(1-9) can induce mitochondrial fusion through DRP1 phosphorylation. Secondly, angiotensin-(1-9) blocked mitochondrial fission and intracellular calcium dysregulation in a model of norepinephrine-induced cardiomyocyte hypertrophy, preventing the activation of the calcineurin/NFAT signaling pathway. To further investigate angiotensin-(1-9) anti-hypertrophic mechanism, we performed RNA-seq studies, identifying the upregulation of miR-129 under angiotensin-(1-9) treatment. miR-129 decreased the transcript levels of the protein kinase A inhibitor (PKIA), resulting in the activation of the protein kinase A (PKA) signaling pathway. Finally, we showed that PKA activity is necessary for the effects of angiotensin-(1-9) over mitochondrial dynamics, calcium handling and its anti-hypertrophic effects.

AT2 Receptor Mediated Activation of the Tyrosine Phosphatase PTP1B Blocks Caveolin-1 Enhanced Migration, Invasion and Metastasis of Cancer Cells.

: The renin-angiotensin receptor AT2R controls systemic blood pressure and is also suggested to modulate metastasis of cancer cells. However, in the latter case, the mechanisms involved downstream of AT2R remain to be defined. We recently described a novel Caveolin-1(CAV1)/Ras-related protein 5A (Rab5)/Ras-related C3 botulinum toxin substrate 1 (Rac1) signaling axis that promotes metastasis in melanoma, colon, and breast cancer cells. Here, we evaluated whether the antimetastatic effect of AT2R is connected to inhibition of this pathway. We found that murine melanoma B16F10 cells expressed AT2R, while MDAMB-231 human breast cancer cells did not. AT2R activation blocked migration, transendothelial migration, and metastasis of B16F10(cav-1) cells, and this effect was lost when AT2R was silenced. Additionally, AT2R activation reduced transendothelial migration of A375 human melanoma cells expressing CAV1. The relevance of AT2R was further underscored by showing that overexpression of the AT2R in MDA-MB-231 cells decreased migration. Moreover, AT2R activation increased non-receptor protein tyrosine phosphatase 1B (PTP1B) activity, decreased phosphorylation of CAV1 on tyrosine-14 as well as Rab5/Rac1 activity, and reduced lung metastasis of B16F10(cav-1) cells in C57BL/6 mice. Thus, AT2R activation reduces migration, invasion, and metastasis of cancer cells by PTP1B-mediated CAV1 dephosphorylation and inhibition of the CAV1/Rab5/Rac-1 pathway. In doing so, these observations open up interesting, novel therapeutic opportunities to treat metastatic cancer disease.

Menores niveles circulantes del péptido vasoactivo y cardioprotector angiotensina-(1-9) en pacientes con hipertension arterial pulmonar / Lower circulating levels of angiotensin-(1-9), a vasoactive and cardio-protective peptide in patients with pulmonary artery hypertension

RESUMEN: Introducción: La vía clásica del sistema renina-angiotensina (SRA) está activado en pacientes con hipertensión arterial pulmonar (HAP). Previamente, hemos encontrado que en la disfunción ventricular post infarto al miocardio experimental la activación del eje clásico del SRA, dado por la enzima convertidora de angiotensina I (ECA) y angiotensina (Ang ) II se correlaciona negativamente con el eje paralelo del SRA dado por la ECA homóloga (ECA2) y el péptido vasoactivo y cardioprotector Ang-(1-9). Resultados preclínicos muestran la eficacia de la administración de Ang-(1-9) en el tratamiento del remodelamiento cardiovascular patológico. Hasta la fecha no existen antecedentes de los niveles circulantes de Ang-(1-9) en pacientes con hipertensión arterial pulmonar comparados con sujetos sanos. Objetivo: Determinar los niveles circulantes del péptido vasoactivo y cardiprotector Ang-(1-9) en pacientes con HAP y compararlos con sujetos sanos pareados por edad y sexo. Métodos: Estudio comparativo transversal en pacientes con HAP (grupo I, OMS) con presión de arteria pulmonar media (mPAP) ≥25 mmHg bajo tratamiento con furosemida (40%), espironolactona (53%), Acenocumarol/Warfarina (47%), Bosentan/Ambrisentan (27%), Sildenafil (80%), iloprost (7%) y digoxina (13%). Los sujetos controles correspondieron a sujetos asintomáticos sanos sin enfermedad cardiovascular, cardiopatía estructural ni pulmonar (n=14). En todos los pacientes se determinó mPAP, proBNP, resistencia vascular pulmonar (RVP, WU), presión capilar pulmonar (PCP, mmHg), gasto cardíaco (L/min), capacidad funcional por test de caminata 6 minutos (TC6M), cambio del área fraccional del ventrículo derecho VD (FAC, %). Se utilizó prueba t de Student y programa estadístico SPSS10.0. Un valor de p < 0,05 fue considerado como estadísticamente significativo. Resultados: Los pacientes ingresados al estudio mostraron: etiología de la HAP, idiopática (86,7%), VIH (13,3%), capacidad funcional I (6,2%), II (68,3) y III (25%) y promedio mPAP 51,3±1,9. Pacientes con HAP (grupo I, OMS) versus sujetos sanos mostraron disminución significativa de FAC, actividad plasmática de la ECA2 y niveles circulantes de Ang-(1-9). En la vía clásica del RAAS pacientes con HAP mostraron mayor actividad plasmática de ECA y niveles circulantes e Ag II. Correlaciones significativas se encontraron entre niveles de Ang-(1-9) y mPAP (r = -0.701, p < 0,001) y Ang-(1-9) vs FAC (r = 0.549, p < 0,01). Conclusiones: En pacientes con HAP (grupo I, OMS), los niveles circulantes de Ang-(1-9) están significativamente disminuidos y se asocian inversamente con la PAP, severidad del remodelamiento y disfunción del ventrículo derecho. El uso terapéutico de Ang-(1-9) como agente vasodilatador y cardioprotector podría ser relevante y potencialmente útil, desde una perspectiva clínica, en la HAP. Ang-(1-9) podría reducir la PAP y mejorar el remodelamiento vascular y del ventrículo derecho en la HAP. Por lo tanto, este péptido podría ser útil como blanco terapéutico en la HAP.

ABSTRACTS: Classic renin-angiotensis pathway (RAP) is activated in patients with pulmonary artery hypertension (PAH). We have previously shown that in patients with post myocardial infarction systolic dysfunction the activation of RAP mediated by angiotensin converting enzyme (ACE) and angiotensin II (Ang II) is inversely correlated with the parallel RAP axis mediated by homologous ACE (ACE2) and by the vasoactive and cardioprotective peptide Ang-(1-9). Pre clinical studies show that administration of Ang-(1-9) leads to a favorable ventricular remodelling. At present there is no information regarding levels of Ang-(1-9) in PAH patients compared to healthy subjects. Methods: 16 PAH patients (WHO group 1), with mean PA pressure > 25mmHg being treated with furosemide (40%), Bosentan/Ambrisentan (27%), Sildenafil (80%), iloprost (7%) were compared with healthy subjects (n=14). mPAP, pro BNP, pulmonary vascular resistance (Wu), pulmonary capillary pressure (PCP mmHg), cardiac output (L/min), functional capacity (6 min walking test) (6mWT), and changes in right ventricular fractional area (RV FA), were measured in all subjects. Results: In HAP subjects, the eiotology of PAH was unknown in 87%, or HIV (13%). Functional class was I (6.2 %), II (68.3%) or III (25%). Mean PAP was 51.3±1.9. Compared to healthy subjects, PAH patients had significantly lower RV FA, ACE2 and Ang-(19) levels. Also they had greater ACE plasma activity and AngII circulating levels. Significant correlations were found between Ang-(1-9) and mPAP (-0.701, p < 0,001) and between Ang-(1-9) and RV FA (r = 0.549, p < 0,01). Conclusion: group I PAH subjects, circulating levels of Ang-(1-9) are significantly lower than in healthy subjects and are inversely related to PAP, severity of ventricular remodeling and right ventricular dysfunction. The use of Ang-(1-9) as a vasodilator and cardioprotector agent could be clinically useful in PAH subjects.

Biomarcadores de fibrosis y función ventricular derecha en maratonistas con distinto grado de entrenamiento: estudio en la maratón de Santiago / Fibrosis and right ventricular function biomarkers in marathon runners: a study at the Santiago, Chile marathon

Resumen: Introducción: Atletas altamente entrenados muestran cambios cardíacos estructurales como adaptación a la sobrecarga, producto del ejercicio repetitivo y extenuante. Se han evidenciado elevación de biomarcadores de remodelado y fibrosis miocárdica posterior al ejercicio intenso en atletas. Sin embargo, el comportamiento de estos biomarcadores según el nivel de entrenamiento previo no se ha evaluado. Objetivo: Investigar biomarcadores de fibrosis y función ventricular derecha en maratonistas con distinto nivel de entrenamiento previo. Métodos: Se incluyeron 36 maratonistas hombres, sanos, que completaron 42 km en la maratón de Santiago. Se dividieron según entrenamiento previo en dos grupos, Grupo 1 (G1): ≥100 km/semana y Grupo 2 (G2): <100 km/semana. Se realizó ecocardiografía transtorácica y se evaluaron niveles plasmáticos de galectina-3 y del propéptido amino terminal del procolágeno tipo III (PIIINP) en la semana previa a la carrera e inmediatamente posterior a ésta. Resultados: Posterior a la maratón, la función sistólica del ventrículo derecho disminuyó en el grupo G2 junto con un aumento significativo de los niveles plasmáticos de PIIIPNP (61±16 a 94±24 ng/mL, p=0,01). Estos cambios no se observaron en el grupo G1 (65 ± 11 a 90±29 ng/mL, p=0,10). Los niveles plasmáticos de galectina-3 aumentaron significativamente en ambos grupos posterior al ejercicio (6,8±2,2 a 19,7±4,9 ng/mL, p 0,012 y 6,0±1,1 a 19,4 ± 5,9 ng/mL, p 0,01) en los grupos G1 y G2, respectivamente). Conclusiones: Atletas con menor grado de entrenamiento, presentan posterior a una maratón un significativo aumento de productos de degradación del colágeno (PIIIPNP) asociado a disminución de la función del ventrículo derecho. Los niveles de galectina-3 plasmática aumentan significativamente en ambos grupos post-esfuerzo independiente del entrenamiento previo.

Abstracts: Introduction: Highly trained athletes show structural cardiac changes as adaptation to overload. Rise in remodeling biomarkers and myocardial fibrosis after intense exercise in athletes has been evidenced; however, the behavior of these biomarkers according to pre-competition training level has not been evaluated. Objective: To evaluate fibrosis biomarkers levels and right ventricle function in marathon runners according to their previous training level, in the period prior to a marathon race and immediately after it. Methods: Thirty-six healthy male marathon runners were included. Subjects were grouped according to their previous training level: Group 1 (G1): ≥100 km/week and Group 2 (G2): <100 km/week. Transthoracic echocardiography along with plasmatic levels of galectin-3 and amino terminal propeptide of type III procollagen (PIIINP) were measured one week previous and immediately after the marathon. Results: Post-effort right ventricle systolic function decreased in G2, together with a significant elevation of PIIIPNP (61±16 to 94±24 ng/mL, p=0.01). These changes were not observed in G1 (from 65±11 to 90±29 ng/mL, p=0.10). Plasma galectin-3 increased significantly in both groups immediately post-exercise (6.8±2.2 to 19.7±4.9 ng/mL, p=0.012, and 6.0±1.1 to 19.4±5.9 ng/mL, p=0.01, in G1 and G2. respectively). Conclusion: Less trained athletes evidenced higher post marathon levels of PIIIPNP which is associated with a decreased global right ventricle function. Plasma galectin-3 levels increased significantly after intense exertion regardless of the intensity of previous training.

En el modelo preclínico de insuficiencia cardíaca por disfunción sistólica en ratón (coartación de aorta torácica) la velocidad de flujo carotídeo determinada precozmente se asocia a función ventricular izquierda tardía / Carotid flow velocity is associated to late ventricular function in mice with preclinic systolic dysfunction induced by thoracic aortic coarctation

Resumen: Los modelos experimentales de falla cardíaca con fracción de eyección disminuida en murinos son pocos. Uno de estos modelos es el de coartación de la aorta torácica en el arco aórtico (COA) en ratones. Un aspecto importante en su desarrollo es la evaluación precoz del procedimiento y su relación con la función sistólica posterior. En este sentido, las velocidades de flujo carotídeo y la relación entre ambos flujos (derecho, pre-coartación; izquierdo post coartación) pueden permitir evaluar tempranamente la precisión del procedimiento y relacionarse más tardíamente con la función sistólica VI. Nuestro objetivo fue comparar precozmente (semana 2 post operatoria) las velocidades de flujo en ambas carótidas (Doppler continuo) y tardíamente (semana 5 postoperatoria) la función sistólica VI (Ecocardiograma de superficie) en ratones seudocoartados o sham (n= 6) vs ratones COA (n = 12). Se confirmó una diferencia estadísticamente significativa en la relación de velocidades de flujo entre ambas carótidas medida precozmente entre los ratones sham y COA (1,1 ± 0,1 vs 2,5 ± 0,5, p< 0,001), lo que se correlacionó con un deterioro significativo de la función sistólica del ventrículo izquierdo evaluada a las 5 semanas en los ratones COA. Conclusión: En este modelo preclínico de falla cardíaca por sobrecarga de presión con fracción de eyección VI disminuida en ratón, el aumento precoz de la velocidad de flujo en la arteria carótida derecha (pre-coartación en el modelo COA) y sobre todo de la relación entre las velocidades de flujo carotídeo entre ambas carótidas se asocia a deterioro importante de la función sistólica VI cinco semanas después de efectuada la COA, lo que permite predecir la efectividad del procedimiento en este modelo experimental.

Abstract: There are few experimental models of heart failure with reduced ejection fraction in murines. One of these models is transverse aortic coarctation (TAC) in mice. However, an important challenge in its development is the early evaluation of the procedure and its relationship with late systolic LV function. In this sense, carotid flow velocities and the relationship between both (right, precoarctation, left post-coarctation) may allow early evaluation of the accuracy of the procedure and be related to late LV systolic function. The aim was to compare early (week 2 post-operative) flow velocities determined in both carotid arteries (by continuous Doppler) with late (week 5 postoperative) LV systolic function (by echocardiogram) in sham (n= 6) vs. TAC (n: 12) mice. We confirmed a statistically significant difference in the early ratio of carotid flow velocities (left/right common carotid velocity ratio) between sham and TAC mice (1.1 ± 0.1 vs 2.5 ± 0.5, p< 0.001) and this correlated well with a deteriorated left ventricular function in the TAC mice after 5 weeks. In this preclinical model of cardiac failure due to pressure overload with reduced LV ejection fraction in the mouse, the early increase in right carotid flow velocity (precoarctation) and especially the relationship between precoarctation/postcoarctation carotid flow velocities is associated with significant impairment of LV systolic function five weeks after the TAC, which allows to predict the effectiveness of the procedure in this experimental model.

Entrenamiento físico de alta intensidad en maratonistas produce mayor remodelado cardíaco y reduce respuesta de estrés oxidativo / High-intensity training in marathon runners increases cardiac remodeling and diminishes oxidative stress response

Resumen: Introducción: El ejercicio físico reduce la mortalidad cardiovascular y genera remodelado cardíaco. Altas cargas de entrenamiento pueden generar remodelado cardíaco adverso. Biomarcadores (BMC) de inflamación Interleukina 6 (IL-6) y de estrés oxidativo Malondialdehído (MDA), potencialmente pueden caracterizar la respuesta al esfuerzo. Objetivo: Evaluar actividad de IL-6 y MDA en respuesta a una maratón en atletas con distinto nivel de entrenamiento y remodelado cardíaco asociado. Sujetos y Métodos: Estudio prospectivo, simple ciego, incluyó 16 atletas que completaron la maratón de Santiago (42 k), separados según entrenamiento previo, grupo 1 (G1, n: 8): Alto ≥ 100 km/semana y grupo 2 (G2, n: 8): Bajo <100 km/semana). Se obtuvo pre y post maratón: niveles de IL-6, MDA y ecocardiografía Doppler transtorácica (ETT); cuantificando cámaras cardíacas izquierdas, derechas y deformación del ventrículo izquierdo (strain longitudinal). Se utilizaron las pruebas de Mann-Whitney, Wilcoxon y Kruskal-Wallis. Resultados: Edad G1: 38.13±7.18 años vs G2: 40.38±6.63 años (NS). Tiempo maratón G1: 185.75±14.87 min vs G2: 219.75±24.92 min (p<0.01). Masa del ventrículo izquierdo G1: 91±21 g/m2 vs G2: 73±12 g/m2 (p<0.01). Volumen aurícula izquierda G1: 39.4±12.6 ml/m2 vs 30.6±4.6 ml/m2 (p<0.01). FEVI G1: 55.8±3.3% vs G2: 58.6±6.7% (NS). MDA G1: PRE 0.17±0.13 uM/L, POST 0.67±0.59 uM/L, G2: PRE 0.29±0.24 uM/L, POST 1.01±1.15 uM/L (p<0.01). IL-6 G1: PRE 2.50±1.35 pg/ml, POST 93.91±27.23 pg/ml vs G2: PRE 4.65±5.89 pg/ml, POST 97.83±30.72 pg/ml (NS). Conclusión: El ejercicio físico aumenta los BMC de inflamación y estés oxidativo (IL-6, MDA). Un entrenamiento físico de alta intensidad disminuye la respuesta de estrés oxidativo y se asocia a un mayor remodelado cardíaco.

Abstract: Background: Exercise reduces cardiovascular mortality and generates cardiac remodeling. High training loads can induce adverse cardiac remodeling, and its associated cardiac remodeling. Therefore, interleukin 6 (IL 6) and malondialdehyde (MDA), biomarkers of inflammatory response and oxidative stress respectively, may have a role in stratifying this risk. Objective: To assess the activity of IL-6 and MDA in response to a marathon race in athletes with different previous training status. Subjects And Methods: Prospective, single-blind study involving 16 male athletes that finished the Santiago Marathon (42 k), allocated into two groups according to their previous training: Group 1 (G1, n: 8) with high training (≥ 100 km/weekly) and Group 2 (G2, n: 8) with low training (< 100 km/weekly). Before and after the race serum levels of IL-6, MDA and transthoracic Doppler echocardiography for cardiac chamber quantification and left ventricle deformation (longitudinal strain) were measured. Mann-Whitney, Wilcoxon, and Kruskal-Wallis tests were used to assess statistical significance. Results: Age G1: 38.13±7.18 years-old vs G2: 40.38±6.63 years-old (NS). Marathon finishing time G1: 185.75±14.87 min vs G2: 219.75±24.92 min (p<0.01). Left ventricle mass G1: 91±21 g/m2 vs G2: 73±12 g/m2 (p<0.01). Left atrium volume G1: 39.4±12.6 ml/m2 vs 30.6±4.6 ml/m2 (p<0.01). LVEF G1: 55.8±3.3% vs G2: 58.6±6.7% (NS). MDA G1: PRE 0.17±0.13 uM/L, POST 0.67±0.59 uM/L, G2: PRE 0.29±0.24 uM/L, POST 1.01±1.15 uM/L (p<0.01). IL-6 G1: PRE 2.50±1.35 pg/ml, POST 93.91±27.23 vs G2: PRE 4.65±5.89 pg/ml, POST 97.83±30.72 pg/ml (NS). Conclusion: Physical exercise generates a rise in biomarkers (IL-6, MDA). Athletes with high-intensity training level have a diminished oxidative stress response post effort and greater cardiac remodeling.

Increased active phase atrial contraction is related to marathon runner performance.

PURPOSE: Left atrial (LA) contraction is essential for left ventricular (LV) filling during exertion. We sought to evaluate the relationship of LA contraction and exercise capacity in trained athletes. METHODS: Sixteen male marathon runners were recruited and allocated into two groups according to their previous training status (≥ or < 100 km peer week). All subjects underwent a baseline cardiopulmonary test to evaluate maximal aerobic capacity and a transthoracic echocardiography previous and immediate post-marathon. LA contractile function evaluation was accomplished by measuring the negative deformation of the post P wave strain curve (LASa). LASa change was defined as LASa pre-marathon minus LASa immediate post-marathon. RESULTS: Mean age was 39 ± 6 years. LA volume index (39 ± 13 vs. 31 ± 5 mL/m2, p = 0.04), LV mass index (91 ± 21 vs. 73 ± 12 g/m2, p = 0.04), VO2 max (59 ± 3 vs. 50 ± 8 mL/kg/min, p = 0.036) were higher in more intensive trained group and marathon time was lower (185 ± 14 vs. 219 ± 24 min, p = 0.017). An increase in LASa after immediate post-marathon was observed in both groups, which was significantly greater in the highly trained group (18.9 ± 5.8 vs. 6.3 ± 3.5%, p < 0.003). Maximum VO2 measured previous to the marathon was inversely related to marathon time and directly correlated to LASa change (rho = 0.744, p = 0.001, rho = 0.546, p = 0.028, respectively). CONCLUSIONS: Athletes with more intensive training load have larger LV mass and LA size. An increase in LA contraction was seen post-marathon, which was significantly greater in the highly trained group. This increase in the LA contraction was related to the maximum VO2 measured previous to the marathon and to performance in a highly demanding test.

Protection of the myocardium against ischemia/reperfusion injury by angiotensin-(1-9) through an AT2R and Akt-dependent mechanism.

Angiotensin-(19), a peptide of the non-classical renin angiotensin system, has been shown to prevent and revert hypertension and cardiac hypertrophy. We hypothetized that systemic delivery of angiotensin-(1-9) following myocardial infarction will also be protective and extend to provide protection during reperfusion of the ischemic heart. Adult Sprague Dawley rats were subjected to left anterior descending artery ligation and treated with angiotensin-(1-9) via osmotic mini-pump for 2 weeks in the presence or absence of Mas receptor or AT2R antagonists (A779 and PD123319, respectively). Myocardial death and left ventricular function were evaluated after infarction. Infarct size and functional parameters were determined in isolated rat hearts after global ischemia/reperfusion in the presence of angiotensin-(1-9) plus receptor antagonists or Akt inhibitor at reperfusion. in vitro, neonatal rat ventricular cardiomyocytes underwent simulated ischemia/reperfusion and angiotensin-(1-9) was co-incubated with A779, PD123319 or Akt inhibitor. Systemic delivery of angiotensin-(1-9) significantly decreased cell death and improved left ventricular recovery after in vivo myocardial infarction. Perfusion with the peptide reduced the infarct size and improved functional recovery after ex vivo ischemia/reperfusion. In vitro, angiotensin-(1-9) decreased cell death in isolated neonatal rat ventricular cardiomyocytes subjected to simulated ischemia/reperfusion. The cardioprotective effects of angiotensin-(1-9) were blocked by PD123319 and Akti VIII but not by A779. Angiotensin-(1-9) limits reperfusion-induced cell death by an AT2R- and Aktdependent mechanism. Angiotensin-(1-9) is a novel strategy to protect against cardiac ischemia/reperfusion injury.

La inhibición de Rho quinasa post infarto mejora el remodelado y la función ventricular: mecanismos involucrados a nivel preclínico / Rho-kinase inhibition post myocardial infarction improves remodeling and systolic function: a preclinical study of intervening factors in a pre-clinical study

Resumen: Objetivo: Determinar algunos mecanismos moleculares por los cuales la activación de ROCK cardíaca post infarto del miocardio (IAM) participa en el remodelado y en deterioro de la función sistólica. Métodos: Determinación simultánea de niveles de proteínas blanco de ROCK cardíaca, de función sistólica in vivo del ventrículo izquierdo (VI) y de fibrosis e hipertrofia cardíaca en ratas con IAM en condiciones de inhibición de ROCK con fasudil. Resultados : Siete días post IAM la masa ventricular relativa aumentó significativamente en un 30% en el grupo MI y se redujo con fasudil. La disfunción sistólica VI mejoró significativamente con fasudil mientras que la activación de ROCK cardíaca se redujo a niveles del grupo control. El inhibidor de ROCK también redujo significativamente los niveles cardíacos elevados de las isoformas ROCK1 y ROCK2, de MHC-β y del colágeno miocárdico. En el grupo con IAM aumentaron significativamente los niveles de fosforilación de ERK 42 y ERK 44 (en 2 veces y en 63%, respectivamente), mientras que en el grupo IAM tratado con fasudil estos niveles fueron similares a los del grupo control. El IAM aumentó significativamente los niveles fosforilados del factor de transcripción GATA-4, que se normalizaron con el inhibidor de ROCK. Conclusiones: La disfunción sistólica post IAM se asoció fuertemente con la activación del ROCK cardíaca y con la fosforilación de proteínas río abajo de ROCK que promueven remodelado cardíaco como β-MHC y la vía ERK / GATA-4.

Abstracts: Objective: to determine some molecular mechanisms by which cardiac ROCK activation after myocardial infarction (MI) intervene in cardiac systolic function decline and remodeling. Methods: simultaneous measurement of different cardiac ROCK target proteins levels, in vivo left ventricular (LV) systolic function, myocardial fibrosis, and hypertrophy in rats with MI under ROCK inhibition with fasudil were performed. Results: seven days after MI the relative ventricular mass increased significantly by 30% in the MI groupand was reduced with fasudil. LV systolic dysfunction improved significantly with fasudil whereas at the same time cardiac ROCK activation was reduced to sham levels. The ROCK inhibitor also reduced increased cardiac levels of both ROCK1 and ROCK2 isoforms, β-MHC levels and myocardial collagen volume fraction decline. MI significantly increased phosphorylation levels of ERK 42 and ERK 44 by 2-fold and 63% respectively whereas in the fasudil-treated MI group these levels were similar to those in the sham group. MI significantly increased phosphorylated levels of the transcription factor GATA-4 which were normalyzed by the ROCK inhibitor. Conclusion: LV systolic dysfunction after MI was strongly associated to cardiac ROCK activation and subsequent phosphorylation of ROCK target proteins that promote ventricular remodeling, such as β-MHC and the ERK/GATA-4 pathway. ROCK inhibition with fasudil significantly improved systolic function, diminished myocardial fibrosis, and normalized β-MHC and ERK/GATA-4 phosphorylation levels.

Novel Therapies Targeting Cardioprotection and Regeneration.

Cardiovascular disease is the leading cause of death worldwide. The heart is susceptible to pathologies that impact the myocardium directly, such as myocardial infarction and consequent heart failure, as well as conditions with indirect cardiac effects, such as cancer treatment-related cardiotoxicity. As the contractile cells of the heart, cardiomyocytes are essential for normal cardiac function. Various stress stimuli may result in transient damage or cell death in cardiomyocytes through apoptosis, necrosis or maladaptive autophagy. Moreover, cardiomyocytes are unable to regenerate; thus, lost cells are replaced with fibrotic tissue, with a potentially severe impact on myocardial function. Several therapeutic agents and strategies to reduce cardiomyocyte damage are currently available. This manuscript reviews the state of the art regarding novel cardioprotective endogenous peptides, such as neuregulin-1, angiotensin-(1-9), growth/differentiation factor-11, growth/differentiation factor- 15 and insulin-like growth factor-1. We discuss their protective effects and therapeutic potential in cardiovascular diseases and the current challenges to harnessing their full cardioprotective power. We also explore targeting of exosomes as a cardioprotective approach along with the therapeutic potential of cardiac regeneration strategies. Further advances associated with these molecules and cardioprotective approaches may provide more effective therapies to attenuate or prevent cardiomyocyte death, thereby preserving the myocardium.

Espironolactona aumenta los niveles circulantes de angiotensina-(1-9) y revierte el remodelado cardíaco en la hipertensión arterial experimental / Spironolactone increases circulating levels of angiotensin-(1-9) and reverts cardiac remodeling in experimental hypertension

Previamente hemos demostrado que la eficacia de enalapril, candesartán y de fasudil -inhibidor de la vía RhoA/ROCK,- en el tratamiento del remodelado cardíaco en la hipertensión (HTA) e infarto al miocardio está mediada por aumento en los niveles circulantes del péptido vasoactivo angiotensina [Ang]-(1-9). Sin embargo, no hay información disponible si el antagonista del receptor de mineralocorticoide, espironolactona (espiro) disminuye el remodelado cardíaco aumentando los niveles circulantes de Ang-(1-9). El objetivo de este trabajo fue determinar si espironolac-tona disminuye el remodelado cardíaco aumentando los niveles circulantes de Ang-(1-9) en la hipertensión arterial experimental. Métodos. Estudio comparativo de 3 grupos experimentales. Se utilizaron ratas Sprague Dawley macho (150 ± 10 grs) unifrectomizadas tratadas con desoxi-corticosterona (DOCA, 60mg/Kg 2 veces sem, im) por 6 semanas. Como controles (Sham) se usaron ratas unifrectomizadas. A partir de la 3° semana las ratas DOCA con HTA> 140 mmHg fueron randomizadas a recibir vehículo o espiro (100 mg/kg día, gavage) por 3 sem. Al finalizar el tratamiento se determinó la presión arterial sistólica (PAS), masa corporal, peso del corazón (PC) y masa cardíaca relativa al largo de la tibia (MCR, mg ventrículos/LT*100). El grado de hipertrofia car-diomiocitaria se determinó midiendo el área y perímetro de los cardiomiocitos y la fibrosis por el contenido de colágeno en cortes teñidos con rojo picrosirio. Resultados (promedio ± ES): Conclusión: Espironolactona disminuye la PAS y aumenta los niveles circulantes de Ang-(1-9). Este aumento en los niveles circulantes de Ang-(1-9) se asocia con una disminución significativa de la hipertrofia y la fibrosis cardiaca hipertensiva. Este nuevo efecto de espironolactona en los niveles circulantes de Ang-(1-9), - péptido vasoactivo de la vía paralela del sistema renina-angiotensina-aldosterona,- podría contribuir al efecto antihipertensivo y disminución del daño cardiaco en la hipertensión y remodelamiento cardiovascular y renal patológico. Estos hallazgos pueden tener relevancia terapéutica en términos que Ang-(1-9) podría disminuir el daño cardiovascular patológico.

We have previously demonstrated that the efficacy of enalapril, candesartan and fasudil,- RhoA / ROCK inhibitor-, in the treatment of cardiac remodeling in hypertension (HT) and myocardial infarction is mediated by an increase in circulating levels of the vasoactive peptide angiotensin (Ang) -(1-9). However, it is not known whether the mineralocorticoid receptor antagonist, spironolactone (spiro) decreases cardiac remodeling by increasing the circulating levels of Ang- (1-9). The aim of this study was to determine whether spironolactone decreases cardiac remodeling by increasing circulating levels of Ang-(1-9) in experimental hypertension. Methods. Comparative study of 3 experimental groups. Unifirectomized male Sprague Dawley rats (150 ± 10 grams) were treated with deoxycorticos-terone (DOCA, 60 mg / kg 2 times a week, im) for 6 weeks. Unifirectomized rats were used as controls (Sham). At 3rd week after surgery, DOCA rats with HTA> 140 mmHg were randomized to receive vehicle or spironolactone (Spiro, 100 mg / kg day, gavage) for 3 weeks. At the end of treatment, systolic blood pressure (SBP), body mass (BM), heart weight (HW) and relative cardiac mass to the tibia length (MCR, mg ventricles / LT * 100) were determined. The degree of cardiomyocyte hypertrophy was determined by measuring the area and perimeter of cardiomyocytes and fibrosis by collagen content in sections stained with picrosirius red. Results (mean ± ES): Conclusion: Spironolactone decreases systolic blood pressure and increases circulating levels of Ang-(1-9). This increase in circulating levels of Ang- (1-9) was associated with a significant decrease in hypertrophy and hypertensive cardiac fibrosis. This new effect of spironolactone on the circulating levels of Ang- (1-9) - vasoactive peptide of the parallel pathway of the re-nin-angiotensin-aldosterone system - could contribute to the antihypertensive effect and decrease of cardiac damage in HT and cardiovascular remodeling and renal disease. These findings may have therapeutic relevance supporting that Ang-(1-9) may decreases pathologic cardiovascular damage.

Sobrevida a mediano plazo en los pacientes con hipertensión arterial pulmonar en la era de terapias vasodilatadoras específicas del territorio vascular pulmonar / Survival of patients with pulmonary arterial hypertension after the advent of specific pulmonary vasodilator therapies

Background: Pulmonary arterial hypertension (PAH) is a rare and progressive disease. Long-term survival remains poor despite of advances in specific vasodilator therapy. Aim: To describe the survival rate in a cohort of PAH patients in two referral centers in Chile. Patients and Methods: One hundred fifteen patients aged 43 ± 15.6 years (85% females) with PAH qualified for this study. Their median pulmonary artery pressure was 55.4 ± 14 mmHg and their six minutes walking capacity was 368 ± 119 m. They were followed for 58 ± 0.4 months and their actual survival rates were compared with the estimated survival using the equation proposed by the French registry of PAH. Results: One, two and three year survival rates were 97, 94 and 89%, respectively. The observed survival rates were greater than the estimated survival. Conclusions: The improvement in survival rates observed in this cohort of patients is similar to what has been described in literature.

Remodelado auricular derecho y niveles plasmáticos de galectina-3 se relacionan con la capacidad funcional de pacientes con hipertensión arterial pulmonar / Right atrial remodeling and plasma leves of galectin-3 are related to functional capacity in patiensts with pulmonary artery hypertension

Introducción: En pacientes con hipertensión arterial pulmonar (HAP) Galectina- 3, biomarcador de fibrosis miocárdica, se ha asociado a marcadores ecocardiográficos de remodelado ventricular derecho. La relación entre Galectina- 3, remodelado auricular derecho (AD) y capacidad funcional (CF) en pacientes con HAP no ha sido explorado. El objetivo fue medir niveles de Galectina-3 y su relación con CF y remodelado AD en pacientes con HAP Metodos: Estudio prospectivo observacional en que se incluyeron 14 pacientes con HAP En todos los pacientes se midieron los niveles de Galectina-3, proBNP, se evaluó la CF mediante test de caminata 6 minutos (TC6M) y se evaluó remodelado AD. Se consideraron para el análisis dos grupos según la distancia caminada en TC6M (> 200 m vs. ≤ 200 m). Resultados: La edad promedio fue 43 ± 10 años, el 84% mujeres. Los niveles de Galectina-3 fueron 16,1 ± 7,4 ng/mL y el TC6M fue 371 ± 142 mts. Los pacientes con TC6M< 200 m presentaron mayores niveles de Galectina-3 (27,3 ± 4,6 vs 13,7 ± 3,8; p=0,006) y mayor volumen AD (151 ± 21 vs 94 ± 43; p=0,04). Además, se observó una correlación inversa entre el área AD y TC6M (-0,71; p=0,03). Conclusión: Niveles elevados de Galectina-3 y parámetros de remodelado adverso en AD se relacionan con una menor CF en pacientes con HAP. Estos hallazgos apuntan a una mejor caracterización de pacientes con HAP y eventualmente la búsqueda de nuevos objetivos terapéuticos.

Background: Galectin-3 is a biomarker of myo-cardial fibrosis and has been associated with echocar-diographic markers of right ventricular remodeling in patients with pulmonary artery hypertension (PAH). The association among Galectin-3 level, right atrial (RA) remodeling and functional capacity (FC) has not been explored. The objective was to measure plasma Galectin-3 concentrations and its relation with RA remodeling and FC in PAH patients. Methods: This is a prospective observational study and 14 PAH patients were included. Galectin-3 and proBNP levels were measured in all patients. FC was estimated by the 6-minute walk test (6MWT) and used to define 2 groups of subjects (≤200m or >200m). RA area and volume were measured by echocardiography from a 4 chamber view. Results: The average age was 43±10 years, 84% of patients were female. Galectin-3 levels were 16.1±7.4 ng / mL and 6MWT was 371±142 m. We observed an inverse correlation between RA area and 6MWT (-0.71;p=0.03). Conclusions: Higher Galectin-3 concentrations and RA adverse remodeling are related to a decreased FC in PAH patients. These findings may lead to a better characterization of PAH patients and eventually new therapeutic targets.

ACE2 and vasoactive peptides: novel players in cardiovascular/renal remodeling and hypertension.

The renin-angiotensin system (RAS) is a key component of cardiovascular physiology and homeostasis due to its influence on the regulation of electrolyte balance, blood pressure, vascular tone and cardiovascular remodeling. Deregulation of this system contributes significantly to the pathophysiology of cardiovascular and renal diseases. Numerous studies have generated new perspectives about a noncanonical and protective RAS pathway that counteracts the proliferative and hypertensive effects of the classical angiotensin-converting enzyme (ACE)/angiotensin (Ang) II/angiotensin type 1 receptor (AT1R) axis. The key components of this pathway are ACE2 and its products, Ang-(1-7) and Ang-(1-9). These two vasoactive peptides act through the Mas receptor (MasR) and AT2R, respectively. The ACE2/Ang-(1-7)/MasR and ACE2/Ang-(1-9)/AT2R axes have opposite effects to those of the ACE/Ang II/AT1R axis, such as decreased proliferation and cardiovascular remodeling, increased production of nitric oxide and vasodilation. A novel peptide from the noncanonical pathway, alamandine, was recently identified in rats, mice and humans. This heptapeptide is generated by catalytic action of ACE2 on Ang A or through a decarboxylation reaction on Ang-(1-7). Alamandine produces the same effects as Ang-(1-7), such as vasodilation and prevention of fibrosis, by interacting with Mas-related GPCR, member D (MrgD). In this article, we review the key roles of ACE2 and the vasoactive peptides Ang-(1-7), Ang-(1-9) and alamandine as counter-regulators of the ACE-Ang II axis as well as the biological properties that allow them to regulate blood pressure and cardiovascular and renal remodeling.

Novel players in cardioprotection: Insulin like growth factor-1, angiotensin-(1-7) and angiotensin-(1-9).

Insulin-like growth factor-1, angiotensin-(1-7) and angiotensin-(1-9) have been proposed to be important mediators in cardioprotection. A large body of evidence indicates that insulin like growth factor-1 has pleotropic actions in the heart (i.e., contractility, metabolism, hypertrophy, autophagy, senescence and cell death) and, conversely, its deficiency is associated with impaired cardiac function. Recently, we reported that insulin like growth factor-1 receptor is also located in plasma membrane invaginations with perinuclear localization, highlighting the role of nuclear Ca(2+) signaling in the heart. In parallel, angiotensin-(1-7) and angiotensin (1-9) acting through Mas receptor and angiotensin type 2 receptor have emerged as a novel anti-hypertensive molecules promoting vasodilatation and preventing heart hypertrophy. In this review we discuss the scientific evidence available regarding insulin-like growth factor-1, angiotensin-(1-7) and angiotensin-(1-9) in cardioprotection and its potential application as novel therapeutic targets for treating cardiac diseases.

El efecto anti-hipertensivo de angiotensina-(1-9) es mediado por aumento temprano de la diuresis y natriuresis / Cardiac arrest associated to intramural hematoma of the anterior descending coronary artery

Introducción: Angiotensina (Ang)-(1-9) posee propiedades anti-hipertensivas y efecto protector a nivel cardiovascular en ratas hipertensas. Sin embargo, se desconoce si estos efectos están asociados a un mecanismo de desbalance de sodio a nivel renal. Objetivo: Determinar si el efecto anti-hipertensivo de Ang-(1-9) está asociado a un mecanismo diurético-na-triurético. Método: Ratas macho Sprague Dawley (200 ± 10g) fueron aleatorizadas para recibir Ang II (400 ng/kgmin) vía bomba osmótica. Como control se utilizaron ratas con operación sham (n=18). Después de 2 semanas desde la instalación de bomba, las ratas Sham e hipertensas fueron randomizadas para recibir vehículo (n=10), Ang-(1-9) (602 ng/kg/min, n=17) o una co-administración de Ang-(1-9) y A779 (100 ng kg-1min-1, n=7 bloqueador del receptor MAS) por 2 semanas. Resultados: Se determinó la presión arterial sistólica (PAS), masa ventricular relativa (MVR), área y perímetro de los cardiomiocitos (AC y PC) y la fracción volumétrica de colágeno total (FVCT). Para evaluar la diuresis y natriuresis se utilizaron ratas normotensas que fueron randomizadas para recibir vehículo (n=8) o Ang-(1-9) (600 ngKg-1min-1, n=8) por 6 días. Se observó un incremento significativo(p<0.05) de PAS (33%), MVR (17%), AC (64%), PC (20%), FVCT (46%). La administración crónica de Ang-(1-9) disminuyó PAS (20%), MVR (13 %), AC (35%), PC (20%) y FVCT (20%). Estos efectos no fueron mediados por el receptor MAS. Al comparar las ratas normotensas tratadas con vehículo o Ang-(1-9), se observó un aumento significativo de la diuresis y natriuresis en los días 2 y 3 en los animales con infusión de Ang-(1-9). Conclusión: Ang-(1-9) reduce la hipertensión y el remodelamiento cardíaco en ratas hipertensas. En animales normotensos se demostró que el tratamiento con Ang-(1-9)-induce diuresis y natriuresis. Este es el primer reporte que señala que el efecto de Ang-(1-9) está asociado a una regulación del sodio a nivel renal.

Background: Angiotensin-(1-9) has anti-hypertensive properties and protective cardiovascular effect in hypertensive rats. However, it is unknown whether its effects are related to a kidney mechanism to balance sodium. Aim: To determine if the anti-hypertensive effect of Ang-(1-9) is associated to a diuretic-natriuretic mechanism. Method: Sprague Dawley male rats (200±10 grs) were randomized to receive Angiotensin II by osmotic pump (400 ng/kg/min). Sham operated rats were utilized as control (n=18). Two weeks after pump setting, Sham rats with hypertension were randomized to receive placebo (n=10), Ang-(1-9)(602 ng/kg/min, n=17) or Ang-(1-9) plus A779 (Ang-(1-7) Receptor Mas blocker, 100ng/kg-1min-1, n=7) co-administration for two weeks. Arterial systolic pressure (PAS), ventricular relative mass (MVR), cardiomyocytes area and perimeter (AC and PC) and total collagen volume fraction (FVCT) were measured. Normotensive rats were utilized to evaluate diuresis and natriuresis which were randomized to receive placebo (n=8) or Ang-(1-9) (600ng/kg-1/min-1, n=8) for six days. Results: It was observed a significant rise (p<0.05) of PAS (33%), MVR (17%), AC (64%), PC (26%), FVCT (46%) was observed. Chronic administration of Ang-(1-9) reduced PAS (20%), MVR (13%), AC (35%), PC (20%) and FCVT (20%). All those effects were not mediated by Mas receptor. A significant raise was observed of diuresis and natriuresis at the second and third day of treatment in rats receiving Ang-(1-9) in comparison with normotensive rats treated with placebo. Conclusion: Ang-(1-9) reduces hypertension and cardiac remodeling in hypertensive rats. Ang-(1-9) induces natriuresis and diuresis in normotensive rats. This is the first report showing that Ang-(1-9) is associated to sodium balance in the kidney.