Our long-range goal is to elucidate the role of intracellular mineral ions (Na+, K+, free Mg2+ & free Ca2+) and oxidative stress in the pathophysiology of essential hypertension and type 2 diabetes. We seek to understand how the regulation of intracellular concentrations of essential metal ions and membrane lipids goes astray in health disorders, especially hypertension and diabetes. Our main research tool is NMR spectroscopy. Our laboratory played a key role in the development of NMR methods for measuring various intracellular cations and we also have considerable expertise in the use of 1H NMR for analyzing membrane phospholipid composition and the degree of membrane fatty acid unsaturation (double bonds) and average chain length. Oxidative stress, which may play a contributory role in the pathogenesis of diabetes as well as hypertension, causes peroxidative degradation of membrane lipids resulting in a loss of fatty acid double bonds that can be quantitated by 1H NMR. The following specific aims will be pursued: (1) To investigate the mechanism of altered renal sodium homeostasis in salt-sensitive hypertension; (2) To demonstrate that oxidative stress, which results in overproduction of reactive oxygen species (ROS), can cause loss of unsaturation in fatty acyl chains of membrane phospholipids as measured by 'H NMR, and to test the hypothesis that peroxidative degradation of lipids as measured by loss of membrane fatty acid unsaturation during oxidative stress results in intracellular ionic changes similar to those seen in essential hypertension; (3) To investigate a possible protective role of magnesium against oxidative stress and whether there is a decrease in antioxidant capacity, as measured by glutathione (GSH) levels, in tissues exposed to low Mg environment; (4) To test the hypothesis that a deficit in membrane fatty acid unsaturation is associated with human essential hypertension and to investigate if there is an alteration in sphingomyelin-ceramide pathway in hypertension; (5) To find out if impairment of nitric oxide synthesis by inhibition of nitric oxide synthase, which causes hypertension in a normal rat, produces membrane lipid changes similar to those seen in essential hypertension; (6) To test the hypothesis that hyperglycemia causes peroxidative degradation,of membrane lipids as measured by 1H NMR, especially in vascular tissue, and, if so, whether hyperglycemia associated loss of fatty acid unsaturation and intracellular ionic alterations can be reversed by dietary antioxidants such as vitamin C and E; (7) To investigate increased vulnerability of hypertensive as well as hyperglycemic kidney and myocardium to ischemic damage and its relationship to increased perexidative degradation of membrane lipids; and (8) To design, develop and test a method for non-invasive measurement of """"""""intracellular sodium using triple-quantum filtered (TQ)23 Na NMR. The proposed NMR investigations of intracellular ions and oxidative stress in hypertension and hyperglycemia condition may eventually lead to better strategies for the management of these health disorders. ? ? ?
