This grant request is to continue studies of lung ischemia reperfusion injury. Ischemia reperfusion represents a potentially important mechanism for lung damage associated with pulmonary embolism, lung transplantation, and a variety of syndromes resulting in decreased pulmonary blood flow. During the preceding period of grant support, we have demonstrated that oxidation of lung tissue cellular components represents an initial manifestation of ischemia/reperfusion. A major finding was that significant oxidative lung injury occurred during lung ischemia and was unrelated to tissue anoxia. This renewal application will evaluate the mechanisms and pathways for oxidative injury. To explain the INITIATING factor that leads to oxyradical production in the absence of preceding anoxia, we have proposed a new mechanism based on sensing of the altered mechanical events associated with ischemia. The hypothesis is that decreased flow results in alterations of the endothelial cell membrane leading to increased production of oxyradicals and delocalization of Fe++/Fe+++ from tissue iron stores. The transducer for the """"""""sensing"""""""" of ischemia may be the flow-activated K+ channels. Ischemia/reperfusion and the role of membrane perturbations will be studied with the isolated perfused rat lung and with bovine pulmonary artery endothelial cells in culture. Oxidation of tissue components is measured by thiobarbituric acid reactive substance (TBARS), conjugated dienes, and protein carbonyls. Tissue oxidation and release of Fe++, H2O2, and NO will be measured during ischemia, as a function of perfusate K+, and with activators and inhibitors of membrane K+ channels. As a second major goal, an in vivo rat model of lung ischemia reperfusion injury for comparison with the isolated lung model will be produced by reversible ligation of a major pulmonary artery. Our hypothesis is that tissue oxidative injury will be evident during the ischemic period, with amplification during reperfusion associated with influx of polymorphonuclear leukocytes. The relative contribution of the ischemic and reperfusion periods in the genesis of injury and the role of tissue oxygenation will be evaluated. The third major goal will evaluate the hypothesis that lung antioxidant enzymes are a target for protein oxidation during ischemic injury nd that protection is afforded by augmentation of antioxidant defenses. Antioxidant defenses will be augmented through use of mercaptoproprionylglycine (MPG), a sulfhydryl-based antioxidant and by specific targeting of antioxidant enzymes to pulmonary endothelium through coupling to a monoclonal antibody specific for lung endothelial angiotensin converting enzyme (ACE). The results of this program will provide insights into the mechanisms for tissue injury associated with lung ischemia/reperfusion and will indicate potential protective agents to prevent tissue damage.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL041939-06A1
Application #
2220213
Study Section
Lung Biology and Pathology Study Section (LBPA)
Project Start
1988-09-30
Project End
1998-03-31
Budget Start
1994-04-22
Budget End
1995-03-31
Support Year
6
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Physiology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Chatterjee, Shampa; Nieman, Gary F; Christie, Jason D et al. (2014) Shear stress-related mechanosignaling with lung ischemia: lessons from basic research can inform lung transplantation. Am J Physiol Lung Cell Mol Physiol 307:L668-80
Chatterjee, Shampa; Chapman, Kenneth E; Fisher, Aron B (2008) Lung ischemia: a model for endothelial mechanotransduction. Cell Biochem Biophys 52:125-38
Fisher, A B (2004) Reactive oxygen species and cell signaling with lung ischemia. Undersea Hyperb Med 31:97-103
Fisher, Aron B; Al-Mehdi, Abu B; Manevich, Yefim (2002) Shear stress and endothelial cell activation. Crit Care Med 30:S192-7
Al-Mehdi, A B; Zhao, G; Tozawa, K et al. (2000) Depolarization-associated iron release with abrupt reduction in pulmonary endothelial shear stress in situ. Antioxid Redox Signal 2:335-45
Fisher, A B; Al-Mehdi, A B; Muzykantov, V (1999) Activation of endothelial NADPH oxidase as the source of a reactive oxygen species in lung ischemia. Chest 116:25S-26S
Tozawa, K; al-Mehdi, A B; Muzykantov, V et al. (1999) In situ imaging of intracellular calcium with ischemia in lung subpleural microvascular endothelial cells. Antioxid Redox Signal 1:145-54
Wei, Z; Costa, K; Al-Mehdi, A B et al. (1999) Simulated ischemia in flow-adapted endothelial cells leads to generation of reactive oxygen species and cell signaling. Circ Res 85:682-9
Atochina, E N; Balyasnikova, I V; Danilov, S M et al. (1998) Immunotargeting of catalase to ACE or ICAM-1 protects perfused rat lungs against oxidative stress. Am J Physiol 275:L806-17
Al-Mehdi, A B; Zhao, G; Fisher, A B (1998) ATP-independent membrane depolarization with ischemia in the oxygen-ventilated isolated rat lung. Am J Respir Cell Mol Biol 18:653-61

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