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Type: Artigo de periódico
Title: Quantification Of Cardiomyocyte Hypertrophy By Cardiac Magnetic Resonance: Implications For Early Cardiac Remodeling
Author: Coelho-Filho O.R.
Shah R.V.
Mitchell R.
Neilan T.G.
Moreno H.
Simonson B.
Kwong R.
Rosenzweig A.
Das S.
Jerosch-Herold M.
Abstract: BACKGROUND - : Cardiomyocyte hypertrophy is a critical precursor to the development of heart failure. Methods to phenotype cellular hypertrophy noninvasively are limited. The goal was to validate a cardiac magnetic resonance-based approach for the combined assessment of extracellular matrix expansion and cardiomyocyte hypertrophy. METHODS AND RESULTS - : Two murine models of hypertension (n=18, with n=15 controls) induced by L-N-nitroarginine methyl ester (L-NAME) and pressure overload (n=11) from transaortic constriction (TAC) were imaged by cardiac magnetic resonance at baseline and 7 weeks after L-NAME treatment or up to 7 weeks after TAC. T1 relaxation times were measured before and after gadolinium contrast. The intracellular lifetime of water (τic), a cell size-dependent parameter, and extracellular volume fraction, a marker of interstitial fibrosis, were determined with a model for transcytolemmal water exchange. Cardiomyocyte diameter and length were measured on FITC-wheat germ agglutinin-stained sections. The τic correlated strongly with histological cardiomyocyte volume-to-surface ratio (r=0.78, P<0.001) and cell volume (r=0.75, P<0.001). Histological cardiomyocyte diameters and cell volumes were higher in mice treated with L-NAME compared with controls (P<0.001). In the TAC model, cardiac magnetic resonance and histology showed cell hypertrophy at 2 weeks after TAC without significant fibrosis at this early time point. Mice exposed to TAC demonstrated a significant, longitudinal, and parallel increase in histological cell volume, volume-to-surface ratio, and τic between 2 and 7 weeks after TAC. CONCLUSION - : The τic measured by contrast-enhanced cardiac magnetic resonance provides a noninvasive measure of cardiomyocyte hypertrophy. Extracellular volume fraction and τic can track myocardial tissue remodeling from pressure overload.
Rights: fechado
Identifier DOI: 10.1161/CIRCULATIONAHA.112.000438
Date Issue: 2013
Appears in Collections:Unicamp - Artigos e Outros Documentos

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