Cardiovascular Research Advance Access first published online on August 8, 2008
This version [Corrected Proof] published online on September 4, 2008
Cardiovascular Research, doi:10.1093/cvr/cvn222
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Central infusion of aldosterone synthase inhibitor attenuates left ventricular dysfunction and remodelling in rats after myocardial infarction
1 Hypertension Unit, University of Ottawa Heart Institute,H360 40 Ruskin Street, Ottawa, Ontario, Canada K1Y 4W7
2 Novartis Institutes for BioMedical Research,East Hanover, NJ, USA
* Corresponding author. Tel: +1 613 761 4521; fax: +1 613 761 5105. E-mail address: fleenen{at}ottawaheart.ca
Aims: Blockade of mineralocorticoid receptors in the central nervous system (CNS) prevents sympathetic hyperactivity and improves left ventricle (LV) function in rats post-myocardial infarction (MI). We examined whether aldosterone produced locally in the brain may contribute to the activation of mineralocorticoid receptors in the CNS.
Methods and results: Two days after coronary artery ligation, Wistar rats received an intra-cerebroventricular (icv) infusion via osmotic mini-pumps of the aldosterone synthase inhibitor FAD286 at 100 µg/kg/day or vehicle for 4 weeks. LV function was assessed by echocardiography at 2 and 4 weeks, and by Millar catheter at 4 weeks. At 4 weeks post-MI, aldosterone in the hippocampus was increased by 70% and tended to increase in the hypothalamus by 20%. These increases were prevented by FAD286. Across groups, aldosterone in the hippocampus and hypothalamus showed a high correlation. There were no differences in brain corticosterone levels. Compared to sham rats, at both 2 and 4 weeks post-MI rats treated with vehicle showed increased LV dimensions and decreased LV ejection fraction. Icv infusion of FAD286 attenuated these changes in LV dimensions and ejection fraction by 
30%. At 4 weeks post-MI, LV peak systolic pressure (LVPSP) and dP/dtmax/min were decreased and LV end-diastolic pressure (LVEDP) was increased. In rats treated with icv FAD286, LVPSP and dP/dtmin remained normal and LVEDP and dP/dtmax were markedly improved. Post-MI increases in cardiac fibrosis and cardiomyocyte diameter were substantially attenuated by icv FAD286.
Conclusion: These data suggest that aldosterone produced locally in the brain acts as the main agonist of mineralocorticoid receptors in the CNS and contributes substantially to the progressive heart failure post MI.
KEYWORDS Brain; Aldosterone synthase inhibitor; Central infusion; Myocardial infarction; LV dysfunction; LV remodelling; Millar catheter; Echocardiography
Time for primary review: 24 days