Jackeline Moya

Angiotensin-(1-9) reverses experimental hypertension and cardiovascular damage by inhibition of the angiotensin converting enzyme/Ang II axis.

Background: Little is known about the biological effects of angiotensin-(1–9), but available evidence shows that angiotensin-(1–9) has beneficial effects in preventing/ameliorating cardiovascular remodeling. Objective: In this study, we evaluated whether angiotensin-(1–9) decreases hypertension and reverses experimental cardiovascular damage in the rat. Methods and results: Angiotensin-(1–9) (600 ng/kg per min for 2 weeks) reduced already-established hypertension in rats with early high blood pressure induced by angiotensin II infusion or renal artery clipping. Angiotensin-(1–9) also improved cardiac (assessed by echocardiography) and endothelial function in small-diameter mesenteric arteries, cardiac and aortic wall hypertrophy, fibrosis, oxidative stress, collagen and transforming growth factor type &bgr; − 1 protein expression (assessed by western blot). The beneficial effect of angiotensin-(1–9) was blunted by coadministration of the angiotensin type 2(AT2) receptor blocker PD123319 (36 ng/kg per min) but not by coadministration of the Mas receptor blocker A779 (100 ng/kg per min). Angiotensin-(1–9) treatment also decreased circulating levels of Ang II, angiotensin-converting enzyme activity and oxidative stress in aorta and left ventricle. Whereas, Ang-(1–9) increased endothelial nitric oxide synthase mRNA levels in aorta as well as plasma nitrate levels. Conclusion: Angiotensin-(1–9) reduces hypertension, ameliorates structural alterations (hypertrophy and fibrosis), oxidative stress in the heart and aorta and improves cardiac and endothelial function in hypertensive rats. These effects were mediated by the AT2 receptor but not by the angiotensin-(1–7)/Mas receptor axis.

Mechanisms of favorable effects of Rho kinase inhibition on myocardial remodeling and systolic function after experimental myocardial infarction in the rat.

Objective: The objective of this study was to determine the molecular mechanisms by which cardiac Rho-associated coiled-coil containing protein kinase (ROCK) activation after myocardial infarction (MI) does 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. Results: Seven days after MI, the ventricular mass increased significantly by 5.6% in the MI group and was reduced with fasudil. LV systolic dysfunction improved significantly with fasudil whereas cardiac ROCK activation was reduced to sham levels. The ROCK inhibitor also reduced increased cardiac levels of both ROCK1 and ROCK2 isoforms, cardiomyocyte ROCK2 fluorescence levels and β-myosin heavy chain (MHC) levels in addition to myocardial collagen volume fraction decline. Compared with sham rats, troponin phosphorylation levels after MI were similar and ROCK inhibition reduced them. MI significantly increased phosphorylation levels of extracellular-signal-regulated kinase (ERK) 42 and ERK 44 by twofold 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 and the ROCK inhibitor normalized them. Conclusions: LV systolic dysfunction after MI was strongly associated with 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.

Mayores niveles de ECA y Angiotensina II determinados genéticamente, se asocian a menor actividad del eje ECA2/angiotensina-(1-9) y mayor remodelamiento de la pared aórtica de ratas hipertensas

El polimorfismo del gen de la enzi-ma convertidora de angiotensina I (ECA) determina ma-yor actividad de la ECA y mayores niveles de angioten-sina (Ang) II. Un polimorfismo similar ha sido descrito en humanos. La ECA2, a traves de Ang-(1-9) mas que Ang-(1-7), contrarresta los efectos deletereos de Ang II. Se desconoce si el polimorfismo de la ECA frente a un estimulo hipertensivo modifica el eje ECA2/Ang-(1-9) y determina mayor remodelamiento de la pared aortica de ratas hipertensas.

Angiotensin-(1-9) reduces cardiovascular and renal inflammation in experimental renin-independent hypertension

Graphical abstract Schematic representation on beneficial outcome after Ang‐(1‐9) treatment in renin‐independent hypertension. Figure. No Caption available. Abstract Hypertension‐induced cardiovascular and renal damage can be mediated by activation of the renin‐angiotensin‐aldosterone system. There are different factors beyond renin‐angiotensin‐aldosterone system involved in hypertension and renal damage. Inflammation has emerged as an important mediator of hypertension and cardiovascular and kidney damage. Angiotensin‐(1‐9), a peptide of the renin‐angiotensin system, counter‐regulates both the physiological and pathological actions of angiotensin II. Recent data has shown that angiotensin‐(1‐9) protects the heart and blood vessels from adverse cardiovascular remodeling in experimental models of hypertension and/or heart failure and reduces cardiac fibrosis in stroke‐prone, spontaneously hypertensive rats. These effects are mediated by the angiotensin II type 2 receptor (AT2R). However, it remains unknown whether angiotensin‐(1‐9) also has an anti‐inflammatory effect. In the present study, we investigate whether angiotensin‐(1‐9) reduces inflammation and fibrosis in the heart, arteries, and kidney in a DOCA‐salt hypertensive model and explore the mechanisms underlying the amelioration of end‐organ damage. DOCA‐salt hypertensive rats received: a) vehicle, b) angiotensin‐(1‐9), c) PD123319 (AT2R blocker), d) angiotensin‐(1‐9) plus A779 (a Mas receptor blocker) or e) angiotensin‐(1‐9) plus PD123319, and sham rats were used as a control. Our results showed that angiotensin‐(1‐9) decreased hypertension and increased vasodilation in DOCA‐salt hypertensive rats. These actions were partially inhibited by PD123319. Moreover, angiotensin‐(1‐9) decreased diuresis, fibrosis, and inflammation. These beneficial effects were not mediated by Mas or AT2R blockers. We concluded that angiotensin‐(1‐9) protects against volume overload‐induced hypertensive cardiovascular and kidney damage by decreasing inflammation in the heart, aortic wall, and kidney, through mechanisms independent of the Mas or AT2R.

Angiotensina-(1-9) disminuye el remodelamiento cardiovascular hipertensivo independiente de los niveles de ECA y de angiotensina II

La enzima convertidora de angiotensina I (ECA2) a traves de Angiotensina (Ang)¬(1-9) mas que Ang-(1-7) contrarresta los efectos deletereos de ECA y Ang II. Se desconoce si Ang-(1-9) es efectiva en el tratamiento del remodelamiento cardiovascular (RMCV) hipertensivo, en ratas con polimorfismo del gen de la ECA.

397 HYPERTENSIVE CARDIAC DAMAGE IS REVERSED BY ANGIOTENSIN-(1-9)

Background: We have observed that angiotensin (Ang)-[1-9] exerts cardioprotective effects in myocardial infarcted rats by acting as a competitive ACE inhibitor and decreasing Ang II rather than increasing Ang-(1-7) levels. Objective: To determine the effect of Ang-(1-9) in hypertensive cardiac damage induced by Ang II administration. Methods: Male Sprague Dawley rats (200 ± 10 g) were randomized to receive Ang II (400 ng/Kg min, n = 33) or vehicle, sham rats (S, n = 13) by osmotic pumps. Two weeks after surgery, the hypertensive rats were randomized to receive vehicle (AngII, n = 11), Ang-(1-9) (602 ng/kg/min, n = 9], Ang-(1-9) and A779 [100 ng/kg min, n = 8] and Ang-(1-9) and AT2 receptor blocker PD123319 (36 ng kg−1min−1, n = 7) for 2weeks. The cardiac hypertrophy was determined by relative cardiac mass (RCM: mg ventricles*100/g body weight), cardiomyocytes area (CA, &mgr;m2) and perimeter (CP, &mgr;m). and cardiac fibrosis in the left ventricle (by collagen volumetric fraction, CVF, %). Left ventricular anterior wall thickness (LVAWT, mm) and LV ejection fraction (EF,%) were determined by echocardiography. Results. Compared to sham rats, Ang II induced a significant (p < 0.05) increase of RCM (17%), CA (64%), CP (27%), CVF (46%), LVAWT(12%) and decreased LVEF (-17%). The chronic Ang-(1-9) administration decreased RCM (20%), CA (35%), CP (20%), CVF(22%), LVAWT (14%) and increased LVEF (12%). The effects of Ang-(1-9) were modified by PD123319 but not by A779. Conclusion: Ang-(1-9) reduces hypertensive cardiac damage induced by Ang II through the AT2 receptor rather than through the Mas receptor. Fondecyt 1100874.

1028 ANGIOTENSIN-(1-9) REDUCES HYPERTENSION AND VASCULAR DAMAGE THROUGH THE AT2 RECEPTOR AND BY INCREASING NITRIC OXIDE

Background: Recently, we proposed that Angiotensin (Ang)-[1-9] prevents the hypertension (HT) and exerts cardioprotective effect in the heart probably by antagonizing AngII actions. We hypothesized here that Ang-(1-9) rather than Ang-(1-7), reduces HT and vascular remodeling through AT2 receptor blocker (AT2R) and eNOS. Objective: To determine the antihypertensive and vascular effects of Ang-(1-9) in hypertensives rats and the signaling pathways involved in Ang-(1-9) effects. Methods: Male Lewis rats were made hypertensive by Goldblatt procedure (GB, 2K-1 clip, n = 38). As controls we used sham operated rats (S, n = 12). Four weeks after surgery, hypertensive rats were randomized to receive vehicle (n = 11), Ang-(1-9) (602 ng/kg/min, n = 12), Ang-(1-9)+Mas blocker receptor A779 (100 ng kg−1min−1,n = 8) and Ang-(1-9)+AT2R blocker PD123319 (36 ng kg−1min−1, n = 7). Six weeks after surgery, systolic blood pressure (SBP, mmHg), aortic media thickness (AMT, &mgr;m), TGF-&bgr;1 and collagen I aortic (CA) levels (fold vs S), vascular reactivity assays (VRA, % dilation at 10−9M AcCh), eNOS mRNA levels (fold) and plasma nitrate concentrations (PNC, &mgr;М) were determined. Results: Compared to sham, GB rats had a significant (p < 0.05) increase of SBP (50%), AMT (35%), TGF&bgr;1 (2 fold), CA (4 fold), VRA (5%) and decrease of PNC (40%). The Ang-(1-9) decreased SBP (18%), AMT (10 %), TGF&bgr;1 (1.9 fold), CA (2 fold), increased VRA (20%), and PNC (1.6 fold). These effects were reduced by PD123319 but not by A779. Conclusion: The current study provides strong evidence for antihypertensive and antiremodeling effects of Ang-(1-9) that are mediated both by the AT2R and eNOS. Fondecyt 1100874

La sobreexpresión del gen de enzima convertidora de angiotensina homóloga (ECA2) revierte la hipertensión arterial y el remodelado cardíaco experimental

Resumen: Antecedentes: La sobreexpresion genica de la en-zima convertidora de angiotensina I homologa (ECA2) se asocia con prevencion de la hipertrofia y fibrosis car-diaca dependiente de angiotensina (Ang) II. Sin embargo se desconoce si su sobreexpresion reduce la hipertension arterial (HTA) y revierte el consecuente remodelado mio-cardico (RM) dependiente de Ang II. Objetivo: Determinar si la sobreexpresion adenoviral (Ad) del gen de la ECA2 en el miocardio disminuye la HTA y RM experimental en ratas con niveles genetica-mente determinados de ECA y Ang II . Metodos: Ratas homocigotas normotensas Lewis (LL) y Brown Borway (BN), con menores y mayores niveles circulantes de ECA y Ang II, respectivamente, se hicieron hipertensas por el procedimiento Goldblatt (GB). Como controles se usaron ratas seudo-operadas (sham). A la semana 5 post cirugia y con HTA establecida ≥ 140 mmHg, las ratas se randomizaron a inyeccion intra-miocardica con un AdECA2 o Ad proteina fluorescente verde (GFP) como controles de infeccion. A la semana post infeccion adenoviral, los ratas se sacrificaron y se determinaron peso corporal (PC, g), masa cardiaca (MC, mg), presion arterial sistolica (PAS, mmHg), area (AC, um2) y perimetro (PERC, um) de cardiomiocitos y conte-nido de colageno (%) miocardico (CM), sub-endocardico (CS) y total (CT).

Menores niveles tisulares de la enzima convertidora de angiotensina I homologa (ECA-2) y angiotensina-(1-9) están asociados a mayor remodelamiento de la pared aórtica de ratas hipertensas

Antecedentes: Recientemente hemos propuesto en un modelo experimental de infarto al miocardio una significativa interregulacion entre los niveles de la enzima convertidora de angiotensina I (ECA) y su homologa (ECA-2), junto con que angiotensina (Ang)-(1-9) mas que Ang-(1-7) actuaria como un contrarregulador de Ang II. Sin embargo tal relacion no se ha investigado en el remodelado aortico hipertensivo. Objetivo: Determinar la expresion de ECA y ECA-2, los niveles de Angs I, II, (1-7) y (1-9) y los parametros de remodelado de la pared aortica de ratas hipertensas. Metodos: Ratas normotensas Lewis (n=18) fueron randomizadas a hipertension (HTA) por sobrecarga de presion (modelo Goldblatt, GB, 2 rinones-1 pinzado, n=9). Ratas pseudo-operadas se usaron como controles (S, n=9). A las 6 semanas post cirugia, se determino la masa cardiaca relativa (MCR) y la presion arterial sistolica (PAS). En la aorta toracica se determino el grosor de la tunica media (GTM), area de la TM (ATM), niveles de mRNA de ECA y ECA-2, factor de crecimiento transformante tipo s (TGF-s), inhibidor del activador de plasminogeno (PAI-1) y de la proteina quimioatractante de monocitos (MCP-1) por RT-PCR. La actividad y niveles proteicos de ECA y ECA-2 por fluorimetria 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 ), MCP-1 (53%,) junto con mayor actividad (89%,), niveles proteicos de ECA (130%,) y Ang II (48%,). Esos efectos se asociaron a una significativa disminucion del mRNA, los niveles proteicos y actividad de ECA-2 (- 55%, -41%, y 54%, respectivamente) y a menores niveles aorticos (-25%,) de Ang- (1-9), sin diferencias en los niveles de ang-(1-7). Conclusion: Estos resultados fuertemente sugieren que en la hipertension arterial experimental, el remodelado de la pared aortica esta asociado a una interaccion entre ECA y ECA-2 y los niveles de Ang II y Ang-(1-9), pero no de Ang-(1-7).