title: Cardiac remodeling during and after renin-angiotensin system stimulation in Cyp1a1-Ren2 transgenic rats.
abstract: This study investigated renin-angiotensin system (RAS)-induced cardiac remodeling and its reversibility in the presence and absence of high blood pressure (BP) in Cyp1a1-Ren2 transgenic inducible hypertensive rats (IHR). In IHR (pro)renin levels and BP can be dose-dependently titrated by oral administration of indole-3-carbinol (I3C). Young (four-weeks old) and adult (30-weeks old) IHR were fed I3C for four weeks (leading to systolic BP >200 mmHg). RAS-stimulation was stopped and animals were followed-up for a consecutive period. Cardiac function and geometry was determined echocardiographically and the hearts were excised for molecular and immunohistochemical analyses. Echocardiographic studies revealed that four weeks of RAS-stimulation incited a cardiac remodeling process characterized by increased left ventricular (LV) wall thickness, decreased LV volumes, and shortening of the left ventricle. Hypertrophic genes were highly upregulated, whereas in substantial activation a fibrotic response was absent. Four weeks after withdrawal of I3C, (pro)renin levels were normalized in all IHR. While in adult IHR BP returned to normal, hypertension was sustained in young IHR. Despite the latter, myocardial hypertrophy was fully regressed in both young and adult IHR. We conclude that (pro)renin-induced severe hypertension in IHR causes an age-independent fully reversible myocardial concentric hypertrophic remodeling, despite a continued elevated BP in young IHR.
authors: 1Department of Pharmacology, Maastricht University, The Netherlands.
authors: Bart F J
authors: BF
authors: Heijnen
authors: Leonie P J
authors: LP
authors: Pelkmans
authors: A H Jan
authors: AH
authors: Danser
authors: Ingrid M
authors: IM
authors: Garrelds
authors: John J
authors: JJ
authors: Mullins
authors: Jo G R
authors: JG
authors: De Mey
authors: Harry A J
authors: HA
authors: Struijker-Boudier
authors: Ben J A
authors: BJ
authors: Janssen
mesh_terms: D000375:Aging; D000818:Animals; D006332:Cardiomegaly / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics; D006321:Heart / Q000503:physiopathology*; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology*; D007211:Indoles / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000473:pathology; D051381:Rats; D055647:Rats, Transgenic; D012083:Renin / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects*
chemical_list: D007211:Indoles; C473112:Ren2 protein, mouse; C016517:indole-3-carbinol; D019363:Cytochrome P-450 CYP1A1; D012083:Renin
keywords: Cyp1a1-Ren2 transgenic rat; Renin–angiotensin system; cardiac remodeling; fibrosis; heart failure; hypertrophy