Recent advances in our ability to reestablish flow to ischemic myocardium have raised hopes that salvage of jeopardized myocardium is now possible and may improve survival in afflicted patients. The reperfusion process itself, however, appears to involve its own injury. Evidence exists that a mechanism of this injury involves the oxidation of susceptible chemical moieties, such as the thiol groups of amino acids, thereby structurally changing important cellular proteins. H 2 0 2 will be targeted as the molecule most responsible for this oxidant stress. It is neutral, freely permeable, and is the nexus in the evolution of toxic oxygen metabolites during reperfusion. Creatine kinase (CK) is a critical enzyme in myocardial bioenergetics and is susceptible to this thiol oxidation. It is well recognized that reperfusion of ischemic myocardium is associated with a rapid accumulation of phosphocreatine (PCr) without a corresponding rise in adenosine triphosphate (ATP). In non-ischemic myocardium, this disequilibrium is prevented by CK activity which attenuates the fall in ATP by catalyzing the production of ATP from PCr. Using a multidisciplinary approach involving enzymatic assays, an ischemic/reperfused isolated heart model, and manipulation of H 2 0 2 during reperfusion, the effect of the reperfusion oxidant injury on myocardial CK activity, tissue bioenergetics, and recovery of mechanical function will be assessed. Specifically, the purpose of this study will be 1) to relate CK activity to H2O2 concentrations during reperfusion with recovery of mechanical function, CK activity, and tissue PCr/ATP concentrations. Expected is the elucidation of a mechanism for the alteration of high energy phosphate production during ischemia/reperfusion. An understanding of the biochemical mechanisms of critical enzyme inhibition during reperfusion can thus be related to myocardial bioenergetic imbalance with it subsequent mechanical dysfunctional sequelae. Elucidation of these mechanisms should provide insight into practical therapies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29HL042922-05
Application #
3472670
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Project Start
1989-08-01
Project End
1995-01-31
Budget Start
1993-02-01
Budget End
1994-01-31
Support Year
5
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Allegheny University of Health Sciences
Department
Type
Schools of Medicine
DUNS #
City
Philadelphia
State
PA
Country
United States
Zip Code
19129
Crestanello, J A; Lingle, D M; Millili, J et al. (1998) Pyruvate improves myocardial tolerance to reperfusion injury by acting as an antioxidant: a chemiluminescence study. Surgery 124:92-9
Yokoyama, H; Lingle, D M; Crestanello, J A et al. (1996) Coenzyme Q10 protects coronary endothelial function from ischemia reperfusion injury via an antioxidant effect. Surgery 120:189-96
Kaplan, L J; Blum, H; Bellows, C F et al. (1996) Reversible injury: creatinine kinase recovery restores bioenergetics and function. J Surg Res 62:103-8
Crestanello, J A; Lingle, D M; Kamelgard, J et al. (1996) Ischemic preconditioning decreases oxidative stress during reperfusion: a chemiluminescence study. J Surg Res 65:53-8
Crestanello, J A; Kamelgard, J; Lingle, D M et al. (1996) Elucidation of a tripartite mechanism underlying the improvement in cardiac tolerance to ischemia by coenzyme Q10 pretreatment. J Thorac Cardiovasc Surg 111:443-50
Kaplan, L J; Bellows, C F; Blum, H et al. (1994) Ischemic preconditioning preserves end-ischemic ATP, enhancing functional recovery and coronary flow during reperfusion. J Surg Res 57:179-84
Kaplan, L J; Blum, H; Banerjee, A et al. (1993) Protecting myocardial creatine kinase activity during reperfusion improves bioenergetics and contractile function. J Surg Res 54:311-5
Banerjee, A; Grosso, M A; Brown, J M et al. (1991) Oxygen metabolite effects on creatine kinase and cardiac energetics after reperfusion. Am J Physiol 261:H590-7
Anderson, B O; Brown, J M; Bensard, D D et al. (1990) Reversible lung neutrophil accumulation can cause lung injury by elastase-mediated mechanisms. Surgery 108:262-7;discussion 267-8
Whitman, G J; Martel, D; Weiss, M et al. (1990) Reversal of protamine-induced catastrophic pulmonary vasoconstriction by prostaglandin E1. Ann Thorac Surg 50:303-5