Accumulating evidence indicates that polymorphonuclear leukocytes (PMNs) contribute to the mediation of brain injury following focal ischemic stroke. However, the pathologic mechanisms involved and the cell types injured by PMNs are not known. Both free radical-derived intermediates, proteases, and the myeloperoxidase-chloride system are used by PMNs in host defense. We propose to elucidate the roles played by these chemical and enzymatic systems in vascular injury following focal ischemia. Our project has three aims to test the following hypotheses: 1) Superoxide anion and nitric oxide, separately and through the formation of peroxynitrite, modulate PMN adherence to cerebrovascular endothelium following focal ischemia, thereby affecting vascular permeability, endothelial cell injury, and secondary parenchymal injury; 2) PMN-derived elastase, acting alone and in concert with superoxide anion and peroxynitrite, contributes to microvascular and secondary parenchymal injury in focal stroke; and 3) PMN myeloperoxidase-derived oxidants (hypochlorous acid, monochloramines, and aldehydes) contribute to microvascular and secondary parenchymal cell injury following focal ischemia. Both in vivo and in vitro studies will be undertaken. In mouse models of permanent and temporary focal ischemia, we will use fluorescent videomicroscopy methods to measure PMN-endothelial adherence, loss of BBB integrity, and free radical formation in core and penumbral cortex at 1-48 h after stroke. Myeloperoxidase oxidation products will be measured by mass spectroscopy in core and penumbra and compared regionally and temporally with myeloperoxidase immunocytochemistry findings. Other measured variables will include regional blood flow, edema, and infarct size. Novel mutant mice deficient I PMN elastase and myeloperoxidase will be used in conjunction with pharmacologic interventions to elucidate causality. Injury mechanisms will also be clarified in vitro by studying PMN-mediated injury of cultured cerebrovascular endothelium. The use of PMNs derived from elastase- and MPO-deficient mice, as well as controlled and pharmacologic treatments., will allow us to identify interactions between these injury mechanisms in vitro. These studies will provide considerable mechanistic information regarding vascular injury caused by the acute inflammatory response to focal cerebral ischemia and will help in the design of therapeutics for focal stroke.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
3R37NS021045-19S1
Application #
6701408
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Jacobs, Tom P
Project Start
1985-07-01
Project End
2003-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
19
Fiscal Year
2003
Total Cost
$34,840
Indirect Cost
Name
Washington University
Department
Neurosurgery
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Stowe, Ann M; Adair-Kirk, Tracy L; Gonzales, Ernesto R et al. (2009) Neutrophil elastase and neurovascular injury following focal stroke and reperfusion. Neurobiol Dis 35:82-90
Zhang, Yunhong; Park, Tae S; Gidday, Jeffrey M (2007) Hypoxic preconditioning protects human brain endothelium from ischemic apoptosis by Akt-dependent survivin activation. Am J Physiol Heart Circ Physiol 292:H2573-81
Altay, Tamer; McLaughlin, Bethann; Wu, Jane Y et al. (2007) Slit modulates cerebrovascular inflammation and mediates neuroprotection against global cerebral ischemia. Exp Neurol 207:186-94
Gidday, Jeffrey M; Gasche, Yvan G; Copin, Jean-C et al. (2005) Leukocyte-derived matrix metalloproteinase-9 mediates blood-brain barrier breakdown and is proinflammatory after transient focal cerebral ischemia. Am J Physiol Heart Circ Physiol 289:H558-68
Zhang, Yunhong; Zhang, Xiaochun; Park, Tae S et al. (2005) Cerebral endothelial cell apoptosis after ischemia-reperfusion: role of PARP activation and AIF translocation. J Cereb Blood Flow Metab 25:868-77
Kaplan, S S; Park, T S; Gonzales, E R et al. (2000) Hydroxyethyl starch reduces leukocyte adherence and vascular injury in the newborn pig cerebral circulation after asphyxia. Stroke 31:2218-23
Gidday, J M; Kim, Y B; Shah, A R et al. (1996) Adenosine transport inhibition ameliorates postischemic hypoperfusion in pigs. Brain Res 734:261-8
Park, T S; Gonzales, E R; Shah, A R et al. (1995) Hypoglycemia selectively abolishes hypoxic reactivity of pial arterioles in piglets: role of adenosine. Am J Physiol 268:H871-8
Ruth, V J; Park, T S; Gonzales, E R et al. (1993) Adenosine and cerebrovascular hyperemia during insulin-induced hypoglycemia in newborn piglet. Am J Physiol 265:H1762-8
Gidday, J M; Park, T S (1992) Effect of 2-chloroadenosine on cerebrovascular reactivity to hypercapnia in newborn pig. J Cereb Blood Flow Metab 12:656-63

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