Coronary artery disease can lead to chronic heart failure, need for revascularization (by-pass surgery), or life-threatening cardiac arrhythmias. It is the cause of one and a half million acute myocardial infarctions per year in the USA, more than half of them lethal. Its cost is the highest of all Current medical diseases in the nation. Coronary artery disease affects the blood supply of the heart muscle (myocardium) and, therefore, decreases oxygen delivery to myocardial cells. The mitochondria of cardiac myocytes is one of the major targets for ischemia- induced damage. Limitations of oxygen delivery reduces mitochondrial oxidative phosphorylation and contributes to the reduction of intracellular ATP levels. Some investigators have indicated that the inability of the mitochondria to self-repair following restoration of blood flow may be one of the crucial events leading to the ultimate death of myocardial cells. Although it is not clear if sarcolemmal or mitochondrial damage is the main event in the irreversible damage of the myocardial cell, the role of mitochondrial changes in decreased myocardial functions are not questioned. Recent studies have shown that heat shock protein (HSP) 60, which is a member of the stress protein family and are thought to have a protective role during oxidative stress, is required for the assembly of multimeric enzyme complexes within the mitochondria. We have recently found that during acute occlusion of the descending coronary artery for 30 minutes in the rat heart, which leads to ischemia in the left ventricle, there is a marked and specific increase in HSP6O mRNA level. This finding leads us to believe that HSP6O as other related HSPs may have a protective role and is probably involved in the repair of the mitochondrial enzymatic complexes vital for the normal function of the mitochondria. It is our objective to investigate this ischemia-induced change in HSP6O expression and determine if HSP60 mediates protection processes in the mitochondria that contribute to recovery from ischemic injury in the myocardial cell.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Minority School Faculty Development Awards (K14)
Project #
5K14HL003150-03
Application #
2211222
Study Section
Special Emphasis Panel (ZHL1-CCT-L (F1))
Project Start
1994-08-01
Project End
1998-07-31
Budget Start
1996-08-01
Budget End
1998-07-31
Support Year
3
Fiscal Year
1996
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
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Lau, S; Patnaik, N; Sayen, M R et al. (1997) Simultaneous overexpression of two stress proteins in rat cardiomyocytes and myogenic cells confers protection against ischemia-induced injury. Circulation 96:2287-94
Martin, J L; Mestril, R; Hilal-Dandan, R et al. (1997) Small heat shock proteins and protection against ischemic injury in cardiac myocytes. Circulation 96:4343-8
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Chi, S H; Mestril, R (1996) Stable expression of a human HSP70 gene in a rat myogenic cell line confers protection against endotoxin. Am J Physiol 270:C1017-21
Hutter, J J; Mestril, R; Tam, E K et al. (1996) Overexpression of heat shock protein 72 in transgenic mice decreases infarct size in vivo. Circulation 94:1408-11
Mestril, R; Giordano, F J; Conde, A G et al. (1996) Adenovirus-mediated gene transfer of a heat shock protein 70 (hsp 70i) protects against simulated ischemia. J Mol Cell Cardiol 28:2351-8
Marber, M S; Mestril, R; Chi, S H et al. (1995) Overexpression of the rat inducible 70-kD heat stress protein in a transgenic mouse increases the resistance of the heart to ischemic injury. J Clin Invest 95:1446-56
Oliver, J A (1992) Endothelium-derived relaxing factor contributes to the regulation of endothelial permeability. J Cell Physiol 151:506-11

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