? The fundamental premise of this research project is that the intracellular sodium concentration ([Na+]i) provides one of the most sensitive measures of cellular viability. In vivo [Na+]i measurements are, therefore, crucial in the determination of cellular viability. We have developed Na-23 Magnetic Resonance (MR) methods that use shift reagents (SR) to distinguish intra- and extracellular Na+ content and measure [Na+]i in both isolated organs and animals. It is unlikely, however, that SR will ever be applicable for use in humans. Na-23 MR SR methods will be used to provide an """"""""in vivo gold standard"""""""" measurement of intra- and extracellular Na+ content of the isolated and intact heart. These will be combined with state of the art H-1 MR relaxography measures of intra and extracellular H20 fractions to yield [Na+]i. Two new Na-23 MR methods for the discrimination and quantification of [Na+]i will be developed. These Na-23 MR methods will exploit the inverse Laplace transform to full advantage. One method will exploit the intrinsic transverse relaxation characteristics of the Na+ resonance; the other will explore use of longitudinal relaxation reagents to aid in Na+ discrimination. The methods will be validated in studies of the isolated perfused heart. The methods will be extended to the intact heart in living animals with the ultimate goal of studies in the human heart. Sodium homeostasis is crucially involved in vital cell functions, such as excitability, excitation- contraction coupling, energy metabolism, pH regulation, as well as cardiac growth and development. Numerous reports indicate that [Na+]i is increased in several cardiac pathologies, which include ischemiaheperfusion injury, hypertrophy, and heart failure. An increase in [Na+]i results in functional consequences, including slowed relaxation, slower recovery from acidosis, as well as, increasing incidence of arrhythmias. Project studies will measure [Na+]i in the hypertrophied and failing myocardium of rats and mice following pressure overload. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL078634-03
Application #
7113772
Study Section
Special Emphasis Panel (ZHL1-CSR-K (S1))
Program Officer
Pandit, Sunil
Project Start
2004-09-22
Project End
2008-08-31
Budget Start
2006-09-01
Budget End
2007-08-31
Support Year
3
Fiscal Year
2006
Total Cost
$360,794
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
02115
He, Huamei; Tao, Hai; Xiong, Hui et al. (2014) Rosiglitazone causes cardiotoxicity via peroxisome proliferator-activated receptor ?-independent mitochondrial oxidative stress in mouse hearts. Toxicol Sci 138:468-81
Vinogradov, Elena; Soesbe, Todd C; Balschi, James A et al. (2012) pCEST: Positive contrast using Chemical Exchange Saturation Transfer. J Magn Reson 215:64-73
Zhang, Yajie; Poirier-Quinot, Marie; Springer Jr, Charles S et al. (2011) Active trans-plasma membrane water cycling in yeast is revealed by NMR. Biophys J 101:2833-42
Zhang, Yajie; Poirer-Quinot, Marie; Springer Jr, Charles S et al. (2010) Discrimination of intra- and extracellular 23Na+ signals in yeast cell suspensions using longitudinal magnetic resonance relaxography. J Magn Reson 205:28-37
Vinogradov, Elena; He, Huamei; Lubag, Angelo et al. (2007) MRI detection of paramagnetic chemical exchange effects in mice kidneys in vivo. Magn Reson Med 58:650-5
Ingwall, Joanne S; Balschi, James A (2006) Energetics of the Na(+) pump in the heart. J Cardiovasc Electrophysiol 17 Suppl 1:S127-S133