Quantification of Cardiomyocyte Hypertrophy by Cardiac Magnetic Resonance Implications for Early Cardiac Remodeling

Article

关键词: LEFT-VENTRICULAR HYPERTROPHY;    DIFFUSE MYOCARDIAL FIBROSIS;    TRANSCYTOLEMMAL WATER-EXCHANGE;    PRESERVED EJECTION FRACTION;    END-POINT REDUCTION;    HEART-FAILURE;    LOSARTAN INTERVENTION;    AORTIC-STENOSIS;    HYPERTENSION;    TRANSITION;   

DOI  :  10.1161/CIRCULATIONAHA.112.000438

来源: SCIE

【 摘 要 】

Background- 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- Methods and Results- Two murine models of hypertension (n=18, with n=15 controls) induced by l-N-G-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 (tau(ic)), 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 tau(ic) 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 tau(ic) between 2 and 7 weeks after TAC. Conclusion- Conclusion- The tau(ic) measured by contrast-enhanced cardiac magnetic resonance provides a noninvasive measure of cardiomyocyte hypertrophy. Extracellular volume fraction and tau(ic) can track myocardial tissue remodeling from pressure overload.

【 授权许可】

Free