Contribution of local renin angiotensin system to cardiac hypertrophy, phenotypic modulation, and remodeling in TGR(mRen2)27 transgenic rats

Item Type:	Article
Title:	Contribution of local renin angiotensin system to cardiac hypertrophy, phenotypic modulation, and remodeling in TGR(mRen2)27 transgenic rats
Creators Name:	Ohta, K. and Kim, S.K. and Wanibuchi, H. and Ganten, D. and Iwao, H.
Abstract:	BACKGROUND: The transgenic rat TGR(mRen2)27, carrying the mouse Ren-2 gene, is a new model to elucidate the role of the local renin-angiotensin system in vivo. However, the role of the local renin-angiotensin system in the heart remains to be determined in TGR(mRen2)27. METHODS AND RESULTS: TGR(mRen2)27 were treated with various antihypertensive drugs for 6 weeks to examine the effects on cardiac hypertrophy and gene expression. Cardiac mRNAs were examined by Northern blot analysis. In TGR(mRen2)27, left ventricular hypertrophy was associated with a decrease in alpha-myosin heavy chain expression of 31% and an increase in skeletal alpha-actin and atrial natriuretic polypeptide expression by 2.6- and 21-fold, respectively (P < .05), thereby showing the shift of myocardium to a fetal phenotype. Furthermore, cardiac collagen and laminin expressions were increased in TGR(mRen2)27 (P < .05), suggesting the occurrence of cardiac remodeling. Although treatment of TGR(mRen2)27 with a high dose of TCV-116 (angiotensin AT1 receptor antagonist) or manidipine (calcium antagonist) combined with atenolol (beta 1-adrenergic receptor blocker) completely normalized blood pressure, TCV-116 regressed cardiac hypertrophy and suppressed the changes in cardiac mRNA levels of TGR(mRen2)27 much more potently than manidipine with atenolol. Furthermore, the inhibitory effects of a low dose of TCV-116 on cardiac hypertrophy and altered gene expressions of TGR(mRen2)27 were greater than those of doxazosin (alpha 1-adrenergic receptor blocker) combined with atenolol, despite their similar hypotensive effects. CONCLUSIONS: Our present observations provide evidence that the cardiac renin-angiotensin system in TGR(mRen2)27 is responsible for cardiac hypertrophy, phenotypic modulation, and remodeling.
Keywords:	Genes, Renin, Angiotensin, Hypertrophy, Remodeling, Animals, Mice, Rats
Source:	Circulation
ISSN:	0009-7322
Publisher:	American Heart Association
Volume:	94
Number:	4
Page Range:	785-791
Date:	15 August 1996
Official Publication:	http://circ.ahajournals.org/cgi/content/abstract/94/4/785
PubMed:	View item in PubMed

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