Attenuation of isoproterenol-induced cardiac fibrosis in transgenic rats harboring an angiotensin-(1-7)-producing fusion protein in the heart
| Autor: | Márcia N.M. Alves, Michael Bader, Carlos H. Castro, Gregory T. Kitten, Cristiane R. Fagundes-Moura, Silvia Guatimosim, Marco Fabrício Dias-Peixoto, Enéas Ricardo de Morais Gomes, Anderson J. Ferreira, Timothy L. Reudelhuber, Brit Rentzsch, Pedro W.M. Almeida, Alexandre M. Guimarães, Elisandra Gava, Robson A.S. Santos, Alvair P. Almeida |
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| Rok vydání: | 2010 |
| Předmět: |
Male
medicine.medical_specialty Cardiac fibrosis Transgene Heart Ventricles Blood Pressure Myocardial Reperfusion Injury Biology Rats Sprague-Dawley Fibrosis Heart Rate Internal medicine Renin–angiotensin system Heart rate medicine Animals Telemetry Pharmacology (medical) Myocytes Cardiac Promoter Regions Genetic Microinjection Myosin Heavy Chains Isoproterenol Arrhythmias Cardiac medicine.disease Fusion protein Peptide Fragments Rats Disease Models Animal Endocrinology Blood pressure Gene Expression Regulation Calcium Angiotensin I Rats Transgenic Cardiology and Cardiovascular Medicine |
| Zdroj: | Therapeutic advances in cardiovascular disease. 4(2) |
| ISSN: | 1753-9455 |
| Popis: | Objective: It has been shown that Ang-(1-7) has cardioprotective actions. To directly investigate the effects of Ang-(1-7) specifically in the heart, we generated and characterized transgenic (TG) rats which express an Ang-(1-7)-producing fusion protein driven by the α-MHC promoter. Methods and Results: After microinjection of the transgene into fertilized rat zygotes, we obtained four different transgenic lines. Homozygous animals were analyzed with regard to the expression profile of the transgene by ribonuclease protection assay. Transgene expression was detected mainly in the heart with weak or no expression in other organs. Heterozygous TG(hA-1-7)L7301 rats presented a significant increase in cardiac Ang-(1-7) concentration compared with control rats (17.1±2.1 versus 3.9±1.4 pg/mg protein in SD rats). Radiotelemetry analysis revealed that TG rats presented no significant changes in blood pressure and heart rate compared with normal rats. Overexpression of Ang-(1-7) in the heart produced slight improvement in resting cardiac function (+ dT/dt: 81530±1305.0 versus 77470±345.5 g/s bpm in SD rats, p < 0.05), which was in keeping with the enhanced [Ca2+] handling observed in cardiomyocytes of TG rats. TG(hA-1-7)L7301 rats also showed a greater capacity to withstand stress since TG rats showed a less pronounced deposition of collagen type III and fibronectin induced by isoproterenol treatment in the subendocardial area than in corresponding controls. In addition, hearts from TG rats showed reduced incidence and duration of reperfusion arrhythmias in comparison with SD rats. Conclusion: These results indicate that Ang-(1-7) has blood pressure-independent, antifibrotic effects, acting directly in the heart. |
| Databáze: | OpenAIRE |
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