Our goal is to characterize the role of lipid mediators in the processes of cellular injury and death. We have demonstrated arachidonic acid (AA) involvement in circulatory shock, hypoxia, burn injury, and complement-mediated (C') lung injury. We have also observed complement-mediated stimulation of eicosanoid formation in cultured cells. Furthermore, short-term C' treatment can augment long-term eicosanoid formation in response to appropriate stimuli.
The aims are to characterized the mechanisms by which C' directly stimulates AA metabolism in isolated endothelial cells, b) characterize the nature of the C' interaction with endothelial cells which results in the long-term augmentation of eicosanoid release, and c) carry out studies in a model of endotoxemia to determine whether complement- mediated augmentation of eicosanoid production is of physiologic significance. Specific studies include assessment of the pattern, magnitude, and time course of AA metabolite formation by cultured bovine and human endothelial cells in response to C', investigation of the role of calcium in the complement-mediated activation process, characterization of the membrane phospholipid sources of the AA utilized, and characterization of the role of phospholipases A and C in the stimulation process. Additional studies will include determinations of the stimulus specificity of the long-term complement-mediated augmentation of eicosanoid formation, the time course of this sensitization, whether the pattern of eicosanoid production after C' pretreatment differs from that in normal cells, and the long-term changes in membrane phospholipid AA content which may accompany C' pretreatment. Studies related to the functional importance of this phenomenon will involve experiments carried out in the isolated perfused liver, heart, and vascular ring preparations to determine functional changes which result from endotoxemia in animals which are either C' replete or depleted. The above studies will characterize the biochemical mechanisms by which C' activation can lead to enhanced eicosanoid production and will elucidate the physiologic effect of this phenomenon during a period of global injury. The data obtained will be of value in the understanding therapeutic approaches to the management of clinical disorders which are characterized by C' activation including septicemia, hemodialysis-induced lung injury, burn injury, glomerulonephritis, and various autoimmune diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM028023-10
Application #
3275292
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Project Start
1980-09-01
Project End
1991-08-31
Budget Start
1989-09-01
Budget End
1990-08-31
Support Year
10
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Thomas Jefferson University
Department
Type
Schools of Medicine
DUNS #
061197161
City
Philadelphia
State
PA
Country
United States
Zip Code
19107
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Stothert Jr, J C; Basadre, J O; Gbaanador, G B et al. (1992) Bronchial blood flow during changes in inhaled oxygen and carbon dioxide concentrations in conscious sheep. Circ Shock 36:120-6
Renzi, P M; Flynn, J T (1992) Endotoxin enhances arachidonic acid metabolism by cultured rabbit microvascular endothelial cells. Am J Physiol 263:H1213-21
Flynn, J T; Hellerman, P; Shelly, M A (1990) Zymosan-activated plasma-mediated thromboxane production by the perfused rabbit liver and isolated hepatocytes: involvement of calcium. Prostaglandins 40:383-95
Gee, M H; Tahamont, M V; Flynn, J T et al. (1987) Prostaglandin E1 prevents increased lung microvascular permeability during intravascular complement activation in sheep. Circ Res 61:420-8
Flynn, J T (1987) Inhibition of complement-mediated hepatic thromboxane production by mepacrine, a phospholipase inhibitor. Prostaglandins 33:287-99
Gee, M H; Perkowski, S Z; Tahamont, M V et al. (1986) Thromboxane as a mediator of pulmonary dysfunction during intravascular complement activation in sheep. Am Rev Respir Dis 133:269-73
Gee, M H; Perkowski, S Z; Tahamont, M V et al. (1985) Arachidonate cyclooxygenase metabolites as mediators of complement-initiated lung injury. Fed Proc 44:46-52
Gee, M H; Tahamont, M V; Perkowski, S Z et al. (1985) Arachidonic acid metabolites as mediators of lung injury during intravascular complement activation. Prog Biochem Pharmacol 20:108-19