Clinically, hypomagnesemia is observed in the general population, particularly in women and the elderly, and very frequently in patients with cardiovascular disease. The long term objective of this proposal is to understand the pathobiology of magnesium-deficiency, particularly the enhanced susceptibility to injury due to ischemia/reperfusion of the heart. Our initial findings using rats point to a relevant inability of Mg-deficient hearts to tolerate oxidant stress, such as that induced by ischemia/reperfusion or by exogenously administered oxidants. Our research plan proposes to quantify the endogenous antioxidant status (eg. glutathione, vitamin E, ascorbate) and the endogenous pro-oxidant status (eg. transition metals, peroxidized lipids) with progression of the Mg-deficiency state. ESR-spin trapping will be used extensively to confirm increased production of primary and secondary radical species in ischemic/reperfused hearts, and the suppression, by antioxidant therapy, of impaired contractility and free radical production. The morphological endpoints will enable quantification of cardiomyopathic lesions and localization of enhanced cytokine production, particularly in vascular tissue. Immunochemical and molecular biological techniques include some that have been developed in our laboratory for highly sensitive detection of cytokines at the cellular and genomic levels in small tissue samples. Another novel technique employs the Meridian ACAS cytometer to detect peroxidation products in single endothelial cells, enabling quantification of the cellular susceptibility to oxidant stress in vitro. We submit that the combined research strategies utilizing biophysical, biochemical, immunological and molecular biological techniques should provide significant new information about the mechanisms of cardiac and cellular injury in Mg-deficiency. We hope that this research will lead to a better understanding of Mg-deficiency in man and potentially to better modalities for diagnosing and treating clinical Mg-deficiency.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL049232-01
Application #
3368384
Study Section
Cardiovascular and Renal Study Section (CVB)
Project Start
1993-01-01
Project End
1995-12-31
Budget Start
1993-01-01
Budget End
1993-12-31
Support Year
1
Fiscal Year
1993
Total Cost
Indirect Cost
Name
George Washington University
Department
Type
Schools of Medicine
DUNS #
City
Washington
State
DC
Country
United States
Zip Code
20052
Mak, I T; Dickens, B F; Komarov, A M et al. (1997) Activation of the neutrophil and loss of plasma glutathione during Mg-deficiency--modulation by nitric oxide synthase inhibition. Mol Cell Biochem 176:35-9
Kurantsin-Mills, J; Cassidy, M M; Stafford, R E et al. (1997) Marked alterations in circulating inflammatory cells during cardiomyopathy development in a magnesium-deficient rat model. Br J Nutr 78:845-55
Wiles, M E; Wagner, T L; Weglicki, W B (1997) Effect of acute magnesium deficiency (MgD) on aortic endothelial cell (EC) oxidant production. Life Sci 60:221-36
Kramer, J H; Phillips, T M; Weglicki, W B (1997) Magnesium-deficiency-enhanced post-ischemic myocardial injury is reduced by substance P receptor blockade. J Mol Cell Cardiol 29:97-110
Blasig, I E; Dickens, B F; Weglicki, W B et al. (1996) Uncoupling of mitochondrial oxidative phosphorylation alters lipid peroxidation-derived free radical production but not recovery of postischemic rat hearts and post-hypoxic endothelial cells. Mol Cell Biochem 160-161:167-77
Mak, I T; Komarov, A M; Wagner, T L et al. (1996) Enhanced NO production during Mg deficiency and its role in mediating red blood cell glutathione loss. Am J Physiol 271:C385-90
Weglicki, W B; Mak, I T; Kramer, J H et al. (1996) Role of free radicals and substance P in magnesium deficiency. Cardiovasc Res 31:677-82
Weber, K T (1996) White mineral and substance P. Cardiovasc Res 31:675-6
Walsh, R J; Weglicki, W B; Correa-de-Araujo, R (1996) Distribution of specific substance P binding sites in the heart and adjacent great vessels of the Wistar white rat. Cell Tissue Res 284:495-500
Kramer, J H; Dickens, B F; Misik, V et al. (1995) Phospholipid hydroperoxides are precursors of lipid alkoxyl radicals produced from anoxia/reoxygenated endothelial cells. J Mol Cell Cardiol 27:371-81

Showing the most recent 10 out of 18 publications