Cardiovascular effects of angiotensin-(1-2) in spontaneously hypertensive rats

Cardiovascular effects of angiotensin-(1-2) in spontaneously hypertensive rats

• Autor
• Helen Cristian Marques Tomaz
• Resumo

• INTRODUCTION: Recent studies have shown that acute treatment with Ang-(1-2) (Asp-Arg), an N-terminal dipeptide of angiontensinergic peptides, reduces blood pressure and promotes coronary vasodilation. Therefore, we propose to evaluate whether chronic treatment with this dipeptide promotes beneficial effects in the cardiovascular system of hypertensive rats.

  METHODS: Male normotensive (Wistar) and spontaneously hypertensive (SHR) rats (16-19 weeks; 310-370g) were divided into three groups: Wistar; SHR and SHR+Ang-(1-2) (7.8 µg/kg/h, s.c.). The systolic blood pressure (SBP) was measured during the experimental period (4 weeks) using the tail-cuff plethysmography. Left ventricular function and coronary reactivity to bradykinin (BK) were assessed using the isolated heart preparation with constant flow. Vascular reactivity was evaluated in isolated aortic rings. Histological analyses were performed to evaluate the cardiomyocyte diameter and fibrosis deposition.

  RESULTS: Ang-(1-2) reduced the SBP of the SHR in the first two weeks of treatment (-34.95mmHg at the beginning of the second week, p<0.0001). There was no significant difference in the heart rate among groups. The basal values of left intraventricular systolic and diastolic pressure, dP/dtmax, dP/dtmin, heart rate, perfusion pressure, and coronary resistance were no different among groups. Ang-(1-2) did not change the BK-induced coronary vasodilation or the aortic vasorelaxation induced by acetylcholine or sodium nitroprusside. Ang-(1-2) reduced the cardiomyocyte hypertrophy (SHR: 17.02±0.188 vs SHR+Ang-(1-2): 16.20±0.165µm, p<0.002) and interstitial fibrosis (SHR 7.75±0.43 vs SHR+Ang-(1-2) 6.05±0.42%, p<0.02) in hypertensive rats.

  CONCLUSION: These data show that Ang-(1-2) has beneficial effects in the cardiovascular system decreasing systolic blood pressure, interstitial fibrosis, and cardiomyocyte hypertrophy.

• Palavras-chave
• Cardiovascular Diseases, Hypertension, Renin-Angiotensin System, Peptides, Cardiac Remodeling
• Área Temática
• Apresentações Orais - Sessão VIII

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