Hemodynamic, morphometric and autonomic patterns in hypertensive rats - renin-angiotensin system modulation

Hemodynamic, morphometric and autonomic patterns in hypertensive rats - renin-angiotensin system modulation

Author Zamo, Fernanda de Souza Autor UNIFESP Google Scholar
Lacchini, Silvia Google Scholar
Mostarda, Cristiano Autor UNIFESP Google Scholar
Chiavegatto, Silvana Google Scholar
Moraes-Silva, Ivana Cinthya Autor UNIFESP Google Scholar
Oliveira, Edilamar Menezes de Google Scholar
Irigoyen, Maria Claudia Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract BACKGROUND: Spontaneously hypertensive rats develop left ventricular hypertrophy, increased blood pressure and blood pressure variability, which are important determinants of heart damage, like the activation of renin-angiotensin system. AIMS: To investigate the effects of the time-course of hypertension over 1) hemodynamic and autonomic patterns (blood pressure; blood pressure variability; heart rate); 2) left ventricular hypertrophy; and 3) local and systemic Renin-angiotensin system of the spontaneously hypertensive rats. METHODS: Male spontaneously hypertensive rats were randomized into two groups: young (n=13) and adult (n=12). Hemodynamic signals (blood pressure, heart rate), blood pressure variability (BPV) and spectral analysis of the autonomic components of blood pressure were analyzed. LEFT ventricular hypertrophy was measured by the ratio of LV mass to body weight (mg/g), by myocyte diameter (μm) and by relative fibrosis area (RFA, %). ACE and ACE2 activities were measured by fluorometry (UF/min), and plasma renin activity (PRA) was assessed by a radioimmunoassay (ng/mL/h). Cardiac gene expressions of Agt, Ace and Ace2 were quantified by RT-PCR (AU). RESULTS: The time-course of hypertension in spontaneously hypertensive rats increased BPV and reduced the alpha index in adult spontaneously hypertensive rats. Adult rats showed increases in left ventricular hypertrophy and in RFA. Compared to young spontaneously hypertensive rats, adult spontaneously hypertensive rats had lower cardiac ACE and ACE2 activities, and high levels of PRA. No change was observed in gene expression of Renin-angiotensin system components. CONCLUSIONS: The observed autonomic dysfunction and modulation of Renin-angiotensin system activity are contributing factors to end-organ damage in hypertension and could be interacting. Our findings suggest that the management of hypertensive disease must start before blood pressure reaches the highest stable levels and the consequent established end-organ damage is reached.
Keywords SHR
Hypertension
Blood pressure variability
RAS
LVH
Language English
Sponsor Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Grant number FAPESP: 01/01129-0
FAPESP: 01/00009-0
Date 2010-01-01
Published in Clinics. Faculdade de Medicina / USP, v. 65, n. 1, p. 85-92, 2010.
ISSN 1807-5932 (Sherpa/Romeo, impact factor)
Publisher Faculdade de Medicina / USP
Extent 85-92
Origin http://dx.doi.org/10.1590/S1807-59322010000100013
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000274628800012
SciELO ID S1807-59322010000100013 (statistics in SciELO)
URI http://repositorio.unifesp.br/handle/11600/5578

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