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Ocaranza M.P.,University of Chile | Ocaranza M.P.,University of Santiago de Chile | Rivera P.,University of Chile | Novoa U.,University of Chile | And 7 more authors.
Journal of Hypertension | Year: 2011

Background: Angiotensin II (Ang II) levels depend on renin, angiotensin-converting enzyme (ACE), and on the homologous angiotensin- converting enzyme (ACE2). Increased ACE and Ang II levels are associated with higher Rho kinase activity. However, the relationship between Rho kinase activation and ACE2 in hypertension is unknown. Objective: The role of the Rho kinase signaling pathway in both enzymatic activity and aortic gene expression of ACE2 in deoxycorticosterone acetate (DOCA) hypertensive rats was assessed in the present study. METHODS AND Results: Compared with sham animals, Rho kinase activity was higher by 400% (P < 0.05) in the aortic wall of the DOCA hypertensive rats. In addition to blood pressure reduction, the specific Rho kinase inhibitor fasudil reduced aortic Rho kinase activity to levels observed in the sham control group and increased ACE2 enzymatic activity (by 83% in plasma and by 52% in the aortic wall, P < 0.05), ACE2, and endothelial nitric oxide synthase (eNOS) aortic mRNA levels (by 340 and 40%, respectively, P < 0.05) with respect to the untreated hypertensive DOCA rats. Fasudil also increased significantly plasma levels of Ang-(1-9) in normotensive and in the hypertensive rats. Aortic mRNA and protein levels of transforming growth factor-β1 (TGF-β1), plasminogen activator inhibitor 1 (PAI-1), and monocyte chemoattractant protein 1 (MCP-1) were significantly (P < 0.05) higher in the untreated DOCA rats and were normalized by fasudil administration. Conclusion: In experimental hypertension, Rho-associated, coiled-coil containing protein kinase (ROCK) inhibition reduces blood pressure and increases ACE2 levels and activity. At the same time, ROCK inhibition reduces angiotensin II and increases Ang-(1-9) plasma levels. Fasudil also increases vascular eNOS mRNA levels and reduces aortic overexpression of the remodeling promotion proteins TGF-β1, PAI-1, and MCP-1. This effect might additionally contribute to the antihypertensive and antiremodeling effects of ROCK inhibition in hypertension. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source


Alcaino H.,University of Valparaiso | Mellado R.,University of Santiago de Chile | Garcia L.,Centro Fondap Estudios Moleculares Of La Celula | Diaz-Araya G.,Centro Fondap Estudios Moleculares Of La Celula | And 4 more authors.
Revista Medica de Chile | Year: 2011

Complications and mortality of heart failure are high, despite the availability of several forms of treatment. Uric acid, the end product of purine metabolism would actively participate in the pathophysiology of heart failure. However, there is no consensus about its action in cardiovascular disease. Serum uric acid would have a protective antioxidant activity. This action could help to reduce or counteract the processes that cause or appear as a result of heart failure. However, these protective properties would vanish in the intracellular environment or in highly hydrophobic areas such as atherosclerotic plaques and adipose tissue. This review discusses the paradoxical action of uric acid in the pathophysiology of heart failure. © 2011 Sociedad Médica de Santiago. Source


Ocaranza M.P.,University of Santiago de Chile | Gabrielli L.,University of Santiago de Chile | Mora I.,University of Santiago de Chile | Garcia L.,University of Chile | And 13 more authors.
American Heart Journal | Year: 2011

Background: The small guanosine triphosphatase Rho and its target Rho-kinase have significant roles in experimental remodeling and ventricular dysfunction, but no data are available on Rho-kinase activation in patients with heart failure (HF). We hypothesized that, in patients with chronic HF, Rho-kinase in circulating leukocytes is activated and related to left ventricular (LV) remodeling and dysfunction. Methods: Accordingly, Rho-kinase activity, assessed by the levels of phosphorylated to total myosin light chain phosphatase 1 (MYPT1-P/T) in circulating leukocytes, and echocardiographic LV function data were compared between patients with HF New York Heart Association functional class II or III due to systolic dysfunction (n = 17), healthy controls (n = 17), and hypertensive patients without HF (n = 17). Results: In the control subjects, mean MYPT1-P/T ratio was 1.2 ± 0.2 (it was similar in the hypertensive patients without HF), whereas in patients with HF, it was significantly increased by >100-fold (P < .001). Both MYPT1-P/T and log MYPT1-P/T ratios were inversely correlated with ejection fraction (r = -0.54, P < .03 and r = -0.86, P < .001, respectively). Furthermore, in patients with HF with LV end-diastolic diameter <60 mm, MYPT1-P/T ratio was 35.8 ± 18.1, whereas it was significantly higher in patients with LV diameter ≥60 mm (P < .05). Conclusions: Rho-Kinase activity is markedly increased in patients with stable chronic HF under optimal medical treatment, and it is associated with pathologic LV remodeling and systolic dysfunction. Mechanisms of Rho-kinase activation in patients with HF, its role in the progression of the disease, and the direct effect of Rho-kinase inhibition need further investigation. © 2011 Mosby, Inc. All rights reserved. Source


Ocaranza M.P.,University of Santiago de Chile | Lavandero S.,Centro Fondap Estudios Moleculares Of La Celula | Lavandero S.,Institute Ciencias Biomedicas | Lavandero S.,University of Chile | And 16 more authors.
Journal of Hypertension | Year: 2010

Background: Angiotensin-(1-9) is present in human and rat plasma and its circulating levels increased early after myocardial infarction or in animals treated with angiotensin-converting enzyme inhibitor. However, the cardiovascular effects of this peptide are unknown. Objective: To determine whether angiotensin-(1-9) is a novel anti-cardiac hypertrophy factor in vitro and in vivo and whether this peptide is involved in the pharmacological effects of cardiovascular drugs acting on the renin-angiotensin system. Methods and Results: The administration of angiotensin-(1-9) to myocardial infarcted rats by osmotic minipumps (450 ng/kg per min, n = 6) vs. vehicle (n = 8) for 2 weeks decreased plasma angiotensin II levels, inhibited angiotensin-converting enzyme activity and also prevented cardiac myocyte hypertrophy. However, cardiac myocyte hypertrophy attenuation triggered by angiotensin-(1-9) was not modified with the simultaneous administration of the angiotensin-(1-7) receptor antagonist A779 (100 ng/kg per min, n = 6). In experiments in vitro with cultured cardiac myocytes incubated with norepinephrine (10 μmol/l) or with insulin-like growth factor-1 (10 nmol/l), angiotensin-(1-9) also prevented hypertrophy. In other experimental setting, myocardial infarcted rats (n = 37) were randomized to receive either vehicle (n = 12), enalapril (10 mg/kg per day, n = 12) or angiotensin II receptor blocker candesartan (10 mg/kg per day, n = 13) for 8 weeks. Both drugs prevented left ventricle hypertrophy and increased plasma angiotensin-(1-9) levels by several folds. Angiotensin-(1-9) levels correlated negatively with different left ventricular hypertrophy markers even after adjustment for blood pressure reduction. Conclusion: Angiotensin-(1-9) is an effective and a novel anti-cardiac hypertrophy agent not acting via the Mas receptor. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

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