ABSTRACT
Angiotensin-(1-9) [Ang-(1-9)], generated from Ang I by Ang II converting enzyme 2, has been reported to have protective effects on cardiac and vascular remodeling. However, there is no report about the effect of Ang-(1-9) on pulmonary hypertension. The aim of the present study is to investigate whether Ang-(1-9) improves pulmonary vascular remodeling in monocrotaline (MCT)-induced pulmonary hypertensive rats. Sprague-Dawley rats received Ang-(1-9) (576 µg/kg/day) or saline via osmotic mini-pumps for 3 weeks. Three days after implantation of osmotic mini-pumps, 50 mg/kg MCT or vehicle were subcutaneously injected. MCT caused increases in right ventricular weight and systolic pressure, which were reduced by co-administration of Ang-(1-9). Ang-(1-9) also attenuated endothelial damage and medial hypertrophy of pulmonary arterioles as well as pulmonary fibrosis induced by MCT. The protective effects of Ang-(1-9) against pulmonary hypertension were inhibited by Ang type 2 receptor (AT₂R) blocker, but not by Mas receptor blocker. Additionally, the levels of LDH and inflammatory cytokines, such as TNF-α, MCP-1, IL-1β, and IL-6, in plasma were lower in Ang-(1-9) co-treated MCT group than in vehicle-treated MCT group. Changes in expressions of apoptosis-related proteins such as Bax, Bcl-2, Caspase-3 and -9 in the lung tissue of MCT rats were attenuated by the treatment with Ang-(1-9). These results indicate that Ang-(1-9) improves MCT-induced pulmonary hypertension by decreasing apoptosis and inflammatory reaction via AT₂R.
Subject(s)
Animals , Rats , Angiotensins , Apoptosis , Arterioles , Blood Pressure , Caspase 3 , Cytokines , Hypertension , Hypertension, Pulmonary , Hypertrophy , Interleukin-6 , Lung , Monocrotaline , Plasma , Pulmonary Fibrosis , Rats, Sprague-Dawley , Receptor, Angiotensin, Type 2 , Vascular RemodelingABSTRACT
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.
Subject(s)
Animals , Male , Rats , Spironolactone/pharmacology , Angiotensins/drug effects , Ventricular Remodeling/drug effects , Hypertension/drug therapy , Rats, Sprague-Dawley , Disease Models, Animal , Mineralocorticoid Receptor Antagonists/pharmacologyABSTRACT
[ ABSTRACT] AIM:To investigate the different dose of perindopril on cardiac function in the rabbits with ische-mic cardiac dysfunction .METHODS:Male rabbits weighing 2.5~3.0 kg ( n=30) were randomly divided into 3 groups (n=10):high dose perindopril group (HD group), low dose perindopril group (LD group) and cardiac dysfunction group (CD group).The Left anterior descending coronary artery of the rabbits was ligatured for model preparation .In HD group, the rabbits were treated with perindopril split normal saline solution (1 g/L)2 mL· kg-1 · d-1 .In LD group, the rabbits were treated with perindopril split normal saline solution (0.33 g/L)2 mL· kg -1 · d-1.In CD group, the rabbits were treated with normal saline solution 2 mL· kg-1 · d-1 .Four weeks after treatment , the cardiac function was measured via echocardiography , the mRNA expression of angiotensin-converting enzyme 2 ( ACE2 ) and angiotensin type 2 receptor (AT2R) was analyzed by real-time PCR, serum angiotensin (Ang)-(1-9) and Ang-(1-7) levels were detected by ELISA. RESULTS:Compared with CD group , the cardiac function of the 2 groups treated with perindopril was significantly im-proved (P<0.01), and more improvement in HD group was observed than LD group (P<0.05).The serum angiotensin ( Ang)-(1-9) and Ang-(1-7) level and the mRNA expression of ACE 2 and AT2R in the 2 groups treated with perindopril were significantly improved (P<0.01).Compared with LD group, the mRNA expression of ACE2 and AT2R and the ser-um levels of Ang-(1-9) in HD group were significant improved (P<0.05), while no difference of serum Ang-(1-7) level was observed.Correlation analysis revealed that the improvement of the cardiac function was associated with serum Ang -(1-9) level, mRNA expression of ACE2 and AT2R (P<0.01), but has no significant correlation with serum Ang-(1-7) lev-el.CONCLUSION:High dose of perindopril may improve more cardiac function in ischemic cardiac dysfunction model in rabbits.The mechanism may relate to increasing serum Ang-(1-7) level to activate AT2R.
ABSTRACT
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.
Subject(s)
Animals , Rats , Angiotensin II/pharmacology , Diuresis/drug effects , Natriuresis/drug effects , Antihypertensive Agents/pharmacology , Rats, Sprague-Dawley , Heart/drug effectsABSTRACT
Antecedentes: Recientemente hemos propuesto en un modelo experimental de infarto al miocardio una significativa interregulación entre los niveles de la enzima convertidora de angiotensina I (ECA) y su homóloga (ECA-2), junto con que angiotensina (Ang)-(1-9) más que Ang-(1-7) actuaría como uncontrarregulador de Ang II. Sin embargo tal relación no se ha investigado en el remodelado aórtico hipertensivo. Objetivo: Determinar la expresión de ECA y ECA-2, los niveles de Angs I, II, (1-7) y (1-9) y los parámetros de remodelado de la pared aórtica de ratas hipertensas. Métodos: Ratas normotensas Lewis (n=18) fueron randomizadas a hipertensión (HTA) por sobrecarga de presión (modelo Goldblatt, GB, 2 riñones-1 pinzado, n=9). Ratas pseudo-operadas se usaron como controles (S, n=9). A las 6 semanas post cirugía, se determinó la masa cardíaca relativa (MCR) y la presión arterial sistólica (PAS). En la aorta torácica se determinó el grosor de la túnica media (GTM), área de la TM (ATM), niveles de mRNA de ECA y ECA-2, factor de crecimiento transformante tipo beta (TGF-beta), inhibidor del activador de plasminógeno (PAI-1) y de la proteína quimioatractante de monocitos (MCP-1) por RT-PCR. La actividad y niveles proteicos de ECA y ECA-2 por fluorimetría y Western blot y los niveles de Angs I, II, (1-7) y (1-9) por HPLC y radioinmunoensayo. Resultados: La MCR y la PAS aumentaron significativamente (p<0,05) en el grupo GB respecto a su control S. Las ratas hipertensas mostraron un aumento significativo (p<0.05) del GTM (18 por ciento), ATM (31 por ciento), niveles de mRNA de ECA (164 por ciento), TGF-beta (105 por ciento), PAI-1(51 por ciento), MCP-1 (53 por ciento) junto con mayor actividad (89 por ciento), niveles proteicos de ECA (130 por ciento) y Ang II (48 por ciento). Esos efectos se asociaron a una significativa disminución del mRNA, los niveles proteicos y actividad...
Background: In experimental models of myocardial infarction we have recently proposed a significantinter-regulation between levels of Angiotensin I converting enzyme (ACE) and its homologous, ACE-2; in addition, we have proposed that Angiotensin 1-9 (Ang-(1-9)) rather than Ang-(1-7) counter regulates Ang II. These relations have not been investigated in hypertensive aortic wall remodeling. Aim: To measure de expression of ACE and ACE-2, the aortic wall levels of Ang I, Ang II, Ang-(1-7) and Ang-(1-9), along with parameters of aortic wall remodeling in hypertensive rats. Methods: 18 Lewis rats were randomized to Goldblatt (2 kidneys, 1 clamped) induced hypertension (n=9) or sham operation (controls, n=9). Six weeks after surgery, relative cardiac mass (RCM), systolic blood pressure (SBP), medial layer aortic wall thickness (MLT) and ML area (MLA) were measured. The aortic wall levels of ACE and ACE-2, tissue growth factor beta (TGF- beta), plasminogen activator inhibitor (PAI-1) and monocyte chemoattractant protein (MCP-1) were determined by RT-PCR. Activity and protein levels of ACE and ACE-2 were measured by fluorometry and Western Blot and ANG I, Ang II, Ang-(1-7) and Ang-(1-9) levels were determined using HPLC and radioimmunoassay. Results: RCM and SBP increased significantly in hypertensive as opossed to sham operated rats...