Our laboratory has long been interested in the mechanisms by which lung injury increases pulmonary vascular pressure and fluid conductance. This research proposal will investigate the roles of cyclic nucleotides, lipoxygenase and cyclooxygenase arachidonic acid (AA) products, and free radicals in the pathophysiology of lung injury. Three clinically relevant injury models will be studied: oxidant, HC1 instillation and endotoxin. Measurements will include lung weight, pulmonary arterial, left atrial, and tracheal pressures, and alveolar-capillary or endothelial permeability to 99MTc labeled OPTA (MW 497) and FITC labeled dextran (MW 7000). We will measure by RIA and HPLC the perfusate concentrations of thromboxane and prostacyclin metabolites, and leukotrienes B4 and C4/D4. The first specific aim evaluates the importance of changes in cAMP in lung injury. This proposal will test the hypothesis than an increase in cAMP will antagonize the vascular effects of lung injury by preventing endothelial cell contraction and that fluid conductance varies inversely with cAMP levels. This proposal will also study the effects of cGMP, beta agonists, and alpha agonists on baseline pressure and fluid conductance. We will also morphologically measure contraction of cultured endothelial cells during oxidant challenge and determine if increased cAMP can prevent these changes.
The second aim will test the hypothesis that in the 3 lung injury models AA mediators greatly contribute to the pulmonary edema produced. The proposal will test the hypothesis that the leukotrienes account for the increased permeability in these models. We will also measure AA mediator production by cultured endothelial cells and determine if AA mediators can change cell morphology, permeability and cAMP level. Experiments will determine the effect of H+ and PO2 on production and function of AA metabolites.
The third aim will determine the importance of free radical generation in acute lung injury. We will use unenhanced low level chemiluminescence as a measure of singlet 02 production and lucigenin enhanced chemiluminescence to measure superoxide anion production. We will also use two fairly specific free radical scavengers for singlet 02 od hydroxyl radical. Using these probes we investigate the role of superoxide anion, singlet 02 and hydroxyl radical in lung injury and to determine if free radicals produced by the AA metabolic pathway are biologically important. The results of these experiments may lead to the development of a more rational treatment of acute lung injury in man.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL035483-02
Application #
3349404
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1986-07-01
Project End
1987-12-31
Budget Start
1987-07-01
Budget End
1987-12-31
Support Year
2
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Paky, A; Michael, J R; Burke-Wolin, T M et al. (1993) Endogenous production of superoxide by rabbit lungs: effects of hypoxia or metabolic inhibitors. J Appl Physiol 74:2868-74
Jacobson, J M; Michael, J R; Meyers, R A et al. (1992) Hyperbaric oxygen toxicity: role of thromboxane. J Appl Physiol 72:416-22
Burke-Wolin, T; Abate, C J; Wolin, M S et al. (1991) Hydrogen peroxide-induced pulmonary vasodilation: role of guanosine 3',5'-cyclic monophosphate. Am J Physiol 261:L393-8
Gurtner, G H; Burke-Wolin, T (1991) Interactions of oxidant stress and vascular reactivity. Am J Physiol 260:L207-11
Jacobson, J M; Michael, J R; Jafri Jr, M H et al. (1990) Antioxidants and antioxidant enzymes protect against pulmonary oxygen toxicity in the rabbit. J Appl Physiol 68:1252-9
Kennedy, T P; Michael, J R; Hoidal, J R et al. (1989) Dibutyryl cAMP, aminophylline, and beta-adrenergic agonists protect against pulmonary edema caused by phosgene. J Appl Physiol 67:2542-52
Chakraborti, S; Gurtner, G H; Michael, J R (1989) Oxidant-mediated activation of phospholipase A2 in pulmonary endothelium. Am J Physiol 257:L430-7
Farrukh, I S; Gurtner, G H; Terry, P B et al. (1989) Effect of pH on pulmonary vascular tone, reactivity, and arachidonate metabolism. J Appl Physiol 67:445-52
Farrukh, I S; Michael, J R; Peters, S P et al. (1988) The role of cyclooxygenase and lipoxygenase mediators in oxidant-induced lung injury. Am Rev Respir Dis 137:1343-9