To define biochemical function in hearts cells, we have developed an isolated cardiomyocyte model which can be used in conjunction with NMR spectroscopy to continuously probe the interaction between real time metabolism and ion transport. We have done initial studies using P NMR to monitor energetic metabolites in conjunction with Na NMR to monitor sodium transport. Preliminary data suggest that discrete source and/or location (membrane vs cytoplasm) of cellular energy are critical to the maintenance of myocyte Na- gradients and that there are differences in this function in different models of disease (spontaneous hypertension (SH), diabetes mellitus (DM) and chronic hyperlipidemia (HPL) compared to controls. We proposed to further explore these mechanism by using inhibitors of Na transport (Na, K-ATPase inhibitors, such as ouabain), and specific inhibitors of energetics (2-deoxyglucose or iodoacetate to block glycolysis, oligomycin to block oxidative phosphorylation, and dinitrophenol to uncouple oxidative phosphorylation) alone and combined. Specific questions are: 1) What proportion of Na transport is supported by glycolytic versus oxidative processes, during normoxia or ischemia? 2) How are Na transport and bioenergetics correlates of these altered by disease states? 3) Are altered Na transporter processes the basis of specific pathophysiologic events? 4) Can Na ad P NMR be used to define these processes? To further use this model to investigate clinically relevant problems, additional studies will be done to evaluate the role of the myocyte (as opposed to endothelial, smooth muscle, and white blood cells) in preconditioning protection against the effect of prolonged ischemia. It is hypothesized that prolonged maintenance of Na,K, transport function is intrinsically involved in the preconditioning protection. Smaller increases in Nai during prolonged ischemia stabilized the membrane potential and decrease Na+ and Ca2+ exchange, thereby decreasing Ca2+ overload. Further, it is hypothesized that the protective effect is also related to maintenance of glycolytic function during and after prolonged ischemia. Both of these processes will be monitored with combined Na and P NMR. The goal of this project are two: 1) to demonstrate that specific abnormalities in Na transport are important determinants of cardiac pathophysiology; 2) to explore the use of NMR techniques as a diagnostic tool to evaluate pathophysiological processes with an """"""""eye"""""""" to adapt these techniques for clinical use. These studies will allow delineation of the mechanisms and energetics of Na transport which will allow characterization of disease processes. Myocytes from controls rats and animal models of cardiovascular disease (DM, SH, HPL) will be studied under baseline conditions and during inhibition of specific transport and metabolic processes.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL039208-07
Application #
2219208
Study Section
Diagnostic Radiology Study Section (RNM)
Project Start
1987-07-01
Project End
1999-02-28
Budget Start
1995-04-01
Budget End
1996-02-29
Support Year
7
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Crestanello, Juan A; Doliba, Nicolai M; Babsky, Andriy M et al. (2002) Ischemic preconditioning improves mitochondrial tolerance to experimental calcium overload. J Surg Res 103:243-51
Crestanello, Juan A; Doliba, Nicolai M; Doliba, Natalia M et al. (2002) Effect of coenzyme Q10 supplementation on mitochondrial function after myocardial ischemia reperfusion. J Surg Res 102:221-8
Babsky, A; Doliba, N; Doliba, N et al. (2001) Na+ effects on mitochondrial respiration and oxidative phosphorylation in diabetic hearts. Exp Biol Med (Maywood) 226:543-51
Crestanello, J A; Doliba, N M; Babsky, A M et al. (2000) Opening of potassium channels protects mitochondrial function from calcium overload. J Surg Res 94:116-23
Doliba, N M; Doliba, N M; Chang, Q et al. (1999) Mitochondrial oxidative phosphorylation in heart from stressed cardiomyopathic hamsters. J Mol Cell Cardiol 31:543-53
Doliba, N; Chang, Q; Doliba, N et al. (1998) Metabolic abnormalities and differential responses to stress associated with hamster cardiomyopathy. Proc Soc Exp Biol Med 219:48-56
Babsky, A M; Doliba, M M; Doliba, N M et al. (1998) Adenosine improves cardiomyocyte respiratory efficiency. Ukr Biokhim Zh 70:73-81
van Beek, J H; Osbakken, M D; Chance, B (1996) Measurement of the oxygenation status of the isolated perfused rat heart using near infrared detection. Adv Exp Med Biol 388:147-54
Osbakken, M; Mayevsky, A (1996) Multiparameter monitoring and analysis of in vivo ischemic and hypoxic heart. J Basic Clin Physiol Pharmacol 7:97-113
Ivanics, T; Blum, H; Wroblewski, K et al. (1994) Intracellular sodium in cardiomyocytes using 23Na nuclear magnetic resonance. Biochim Biophys Acta 1221:133-44

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