The aim of this study is to determine the role of leukocytes, oxygen radicals, and leukotrienes in myocardial ischemia and infarction by assessing the effects of several interventions in a canine model involving occlusion-reperfusion of the left circumflex coronary artery. The interventions to be studied include neutrophil depletion by anti-neutrophil antibodies, enzymatic degradation of oxygen radicals by superoxide dismutase and catalase, and leukotriene inhibition by specific pharmacologic antagonists. Several durations of coronary occlusion will be studied for each intervention. The effects of intervention will be assessed in terms of infarct size, neutrophil infiltration of ischemic myocardium, functional integrity of ischemic microvasculature, regional blood flow and ventricular function, and ultimate healing. Infarct size and anatomic area at risk will be determined by a dual staining technique. Neutrophil infiltration will be assessed using autologous indium-111 labeled leukocytes. The microvasculature will be evaluated by permeability to iodine-125 labeled albumin. Myocardial blood flow will be measured using radiolabeled microspheres. Left ventricular function will be analyzed using two-dimensional echocardiography. Infarct healing will be graded by scar thickness and histology. The results will be analyzed to determine whether interference with leukocyte function, free radical activity, or leukotriene action affects tissue damage or healing after reperfusion of ischemic myocardium. The proposed project should substantially augment current knowledge of the role leukocytes play in mediating the effects of myocardial ischemia and reperfusion. It should also extend current concepts of leukotriene participation in the inflammatory response to ischemic myocardium. The results of this study will be important because the increasing use of thrombolytic therapy in patients with myocardial infarction may be exposing them to the untoward effects of reperfusion observed in experimental animals. Ultimately, this study may suggest more effective approaches to the management of patients with acute myocardial infarction.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Physician Scientist Award (K11)
Project #
5K11HL001409-03
Application #
3087158
Study Section
Research Manpower Review Committee (MR)
Project Start
1984-03-01
Project End
1989-02-28
Budget Start
1986-03-01
Budget End
1987-02-28
Support Year
3
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Werns, S W; Lucchesi, B R (1989) Myocardial ischemia and reperfusion: the role of oxygen radicals in tissue injury. Cardiovasc Drugs Ther 2:761-9
Lucchesi, B R; Werns, S W; Fantone, J C (1989) The role of the neutrophil and free radicals in ischemic myocardial injury. J Mol Cell Cardiol 21:1241-51
Werns, S W; Simpson, P J; Mickelson, J K et al. (1988) Sustained limitation by superoxide dismutase of canine myocardial injury due to regional ischemia followed by reperfusion. J Cardiovasc Pharmacol 11:36-44
Werns, S W; Lucchesi, B R (1988) Leukocytes, oxygen radicals, and myocardial injury due to ischemia and reperfusion. Free Radic Biol Med 4:31-7
Werns, S W; Eller, B T; Shea, M J et al. (1988) Protection of reperfused ischemic canine myocardium by CI-922, a new inhibitor of leukocyte activation. J Cardiovasc Pharmacol 12:608-14
Werns, S W; Shea, M J; Mitsos, S E et al. (1986) Reduction of the size of infarction by allopurinol in the ischemic-reperfused canine heart. Circulation 73:518-24
Werns, S W; Shea, M J; Lucchesi, B R (1986) Free radicals and myocardial injury: pharmacologic implications. Circulation 74:1-5
Werns, S W; Shea, M J; Driscoll, E M et al. (1985) The independent effects of oxygen radical scavengers on canine infarct size. Reduction by superoxide dismutase but not catalase. Circ Res 56:895-8
Werns, S W; Shea, M J; Lucchesi, B R (1985) Free radicals in ischemic myocardial injury. J Free Radic Biol Med 1:103-10