101
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Abstract
This chapter will discuss the current knowledge of the contribution of systemic and local inflammation in acute and sub-chronic stages of experimental stroke in both the adult and neonate. It will review the role of specific cell types and interactions among blood cells, endothelium, glia, microglia, the extracellular matrix and neurons - cumulatively called "neurovascular unit" - in stroke induction and evolution. Intracellular inflammatory signaling pathways such as nuclear factor kappa beta and mitogen-activated protein kinases, and mediators produced by inflammatory cells such as cytokines, chemokines, reactive oxygen species and arachidonic acid metabolites, as well as the modifying role of age on these mechanisms, will be reviewed as well as the potential for therapy in stroke and hypoxic-ischemic injury.
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102
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Abstract
Cellular adhesion molecules (CAMs), by mediating the recruitment of circulating leukocytes to the blood vessel wall and their subsequent migration into the subendothelial spaces, play a crucial role in all stages of atherosclerosis. Soluble forms of CAMs, probably derived from proteolytic shedding, are present in the circulation and their blood levels parallel the amount expressed on the cell surface. In patients with peripheral arterial disease (PAD), increased levels of soluble CAMs have been found during exercise-induced claudication, are associated with the presence, the severity and the extent of atherosclerosis in the arteries of the lower limbs, and portend a worse outcome. These findings have provided new insights into the pathophysiology of PAD and its consequences. However, further large population studies are needed to firmly establish whether increased levels of circulating CAMs give additive information to current risk assessment approaches, and to verify whether PAD patients with elevated levels of circulating CAMs would benefit from any specific therapy.
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Affiliation(s)
- Gregorio Brevetti
- Department of Clinical Medicine and Cardiovascular and Immunological Sciences, University 'Federico II', Napoli, Italy.
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103
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Nilupul Perera M, Ma HK, Arakawa S, Howells DW, Markus R, Rowe CC, Donnan GA. Inflammation following stroke. J Clin Neurosci 2006; 13:1-8. [PMID: 16410192 DOI: 10.1016/j.jocn.2005.07.005] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Accepted: 07/16/2005] [Indexed: 01/18/2023]
Abstract
Stroke is one of the leading causes of mortality and morbidity. The stroke process triggers an inflammatory reaction that may last up to several months. Suppression of inflammation using a variety of drugs reduces infarct volume and improves clinical outcomes in animal models of stroke. This benefit occurs even with the initiation of therapy after 3 hours of onset of stroke, beyond the therapeutic window for thrombolysis with tPA. The use of neuroprotectants to suppress inflammation may widen the therapeutic time window for tPA while lessening its side-effects. Suppression of inflammation may also improve outcomes in animal models of haemorrhagic stroke. To date, clinical trials with anti-inflammatory agents in acute ischaemic stroke have failed to improve clinical outcomes. However, because of the potential for broader applicability across all aspects of stroke, a better understanding of anti-inflammatory mechanisms is important.
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Affiliation(s)
- M Nilupul Perera
- National Stroke Research Institute, Austin Health, University of Melbourne, Level 1, Neurosciences Building, 300 Waterdale Road, Heidelberg Heights, Victoria 3081, Australia.
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104
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Rahman RM, Nair SM, Appleton I. Current and future pharmacological interventions for the acute treatment of ischaemic stroke. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.cacc.2005.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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105
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Galvão RIM, Diógenes JPL, Maia GCL, Filho EAS, Vasconcelos SMM, de Menezes DB, Cunha GMA, Viana GSB. Tenoxicam Exerts a Neuroprotective Action after Cerebral Ischemia in Rats. Neurochem Res 2005; 30:39-46. [PMID: 15756931 DOI: 10.1007/s11064-004-9684-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In this study we investigated the effects of Tenoxicam, a type 2 cyclooxygenase (COX-2) inhibitor, on brain damage induced by ischemia-reperfusion. Male Wistar rats (18-month old average) were anesthetized and submitted to ischemia occlusion of both common carotid arteries (BCAO) for 45 min. After 24 h of reperfusion, rats were decapitated and hippocampi removed for further assays. Animals were divided into sham-operated, ischemia, ischemia + Tenoxicam 2.5 mg/kg, and ischemia + Tenoxicam 10 mg/kg groups. Tenoxicam was administered intraperitoneally immediately after BCAO. Histological analyses show that ischemia produced significant striatal as well as hippocampal lesions which were reversed by the Tenoxicam treatment. Tenoxicam also significantly reduced, to control levels, the increased myeloperoxidase activity in hippocampus homogenates observed after ischemia. However, nitrite concentrations showed only a tendency to decrease in the ischemia + Tenoxicam groups, as compared to that of ischemia alone. On the other hand, hippocampal glutamate and aspartate levels were not altered by Tenoxicam. In conclusion, we showed that ischemia is certainly related to inflammation and to increased free radical production, and selective COX-2 inhibitors might be neuroprotective agents of potential benefit in the treatment of cerebral brain ischemia.
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Affiliation(s)
- Rita I M Galvão
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
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106
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Abstract
The current pathophysiological understanding of stroke is substantially based on experimental studies. Brain injury after cerebral ischemia develops from a complex signaling cascade that evolves in an at least partially unraveled spatiotemporal pattern. Early excitotoxicity can lead to fast necrotic cell death, which produces the core of the infarction. The ischemic penumbra that surrounds the infarct core suffers milder insults. In this area, both mild excitotoxic and inflammatory mechanisms lead to delayed cell death, which shows biochemical characteristics of apoptosis. While brain cells are challenged by these deleterious mechanisms, they activate innate protective programs of the brain, which can be studied by means of experimentally inducing ischemic tolerance (i.e., ischemic preconditioning). Importantly, cerebral ischemia not only affects the brain parenchyma, but also impacts extracranial systems. For example, stroke induces a dramatic immunosuppression via an overactivation of the sympathetic nervous system. As a result, severe bacterial infections such as pneumonia occur. Complex signaling cascades not only decide about cell survival, but also about the neurological deficit and the mortality after stroke. These mechanisms of damage and endogenous protection present distinct molecular targets that are the rational basis for the development of neuroprotective drugs.
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Affiliation(s)
- Philipp Mergenthaler
- Department of Experimental Neurology Charité, Humboldt University, Berlin, Germany.
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107
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Arumugam TV, Salter JW, Chidlow JH, Ballantyne CM, Kevil CG, Granger DN. Contributions of LFA-1 and Mac-1 to brain injury and microvascular dysfunction induced by transient middle cerebral artery occlusion. Am J Physiol Heart Circ Physiol 2004; 287:H2555-60. [PMID: 15308480 DOI: 10.1152/ajpheart.00588.2004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the beta2-integrins have been implicated in the pathogenesis of cerebral ischemia-reperfusion (I/R) injury, the relative contributions of the alpha-subunits to the pathogenesis of ischemic stroke remains unclear. The objective of this study was to determine whether and how genetic deficiency of either lymphocyte function-associated antigen-1 (LFA-1) or macrophage-1 (Mac-1) alters the blood cell-endothelial cell interactions, tissue injury, and organ dysfunction in the mouse brain exposed to focal I/R. Middle cerebral artery occlusion was induced for 1 h (followed by either 4 or 24 h of reperfusion) in wild-type mice and in mice with null mutations for either LFA-1 or Mac-1. Neurological deficit and infarct volume were monitored for 24 h after reperfusion. Platelet- and leukocyte-vessel wall adhesive interactions were monitored in cortical venules by intravital microscopy. Mice with null mutations for LFA-1 or Mac-1 exhibited significant reductions in infarct volume. This was associated with a significant improvement in the I/R-induced neurological deficit. Leukocyte adhesion in cerebral venules did not differ between wild-type and mutant mice at 4 h after reperfusion. However, after 24 h of reperfusion, leukocyte adhesion was reduced in both LFA-1- and Mac-1-deficient mice compared with their wild-type counterparts. Platelet adhesion was also reduced at both 4 and 24 h after reperfusion in the LFA-1- and Mac-1-deficient mice. These findings indicate that both alpha-subunits of the beta2-integrins contribute to the brain injury and blood cell-vessel wall interactions that are associated with transient focal cerebral ischemia.
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Affiliation(s)
- Thiruma V Arumugam
- Dept. of Molecular and Cellular Physiology, Louisiana State Univ. Health Sciences Center, 1500 Kings Highway, Shreveport, LA 71130, USA
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108
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Hamann G, del Zoppo GJ. The Cerebral Microvasculature and Responses to Ischemia. Stroke 2004. [DOI: 10.1016/b0-44-306600-0/50045-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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109
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Chen Y, Ruetzler C, Pandipati S, Spatz M, McCarron RM, Becker K, Hallenbeck JM. Mucosal tolerance to E-selectin provides cell-mediated protection against ischemic brain injury. Proc Natl Acad Sci U S A 2003; 100:15107-12. [PMID: 14645708 PMCID: PMC299916 DOI: 10.1073/pnas.2436538100] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have demonstrated that induction of mucosal tolerance to E-selectin, a cytokine-inducible adhesion molecule restricted to activating blood vessels, prevents ischemic and hemorrhagic stroke in spontaneously hypertensive, genetically stroke-prone (SHR-SP) rats. We now examine whether mucosal tolerance to E-selectin has protective effects in ischemic brain damage after permanent middle cerebral artery occlusion (MCAO) in SHR-SP rats and whether these effects are related to generation of regulatory T cells. Rats were exposed to intranasal administration of E-selectin every other day for 10 days (single tolerization group) or on two tolerization schedules separated by 11 days (booster tolerization group). Control groups received PBS on corresponding schedules. MCAO was performed 48 h after the last dose of E-selectin or PBS. There were 45.8% and 37.9% (P < 0.05) decreases of infarction volume in the E-selectin booster group compared with the PBS group at 6 and 48 h, respectively. Single tolerization with E-selectin had only a slight trend toward a decrease in infarction volume (6.3%). CD8-positive cells were decreased in brains of E-selectin booster animals (46.6%, P < 0.01) compared with controls; splenocyte-culture supernatant levels of IL-10 were increased (59.3%, P < 0.05) in E-selectin booster animals. A decrease of infarction volume (34%, P < 0.05) was also observed in SHR-SP rats subjected to MCAO after adoptive transfer of splenocytes from E-selectin-tolerized compared with PBS-tolerized donors. The results indicate that, in addition to preventing stroke, mucosal tolerance to E-selectin is cytoprotective. Thus, immunomodulation targeted to activated blood vessel segments can both reduce stroke occurrence and attenuate brain damage if a stroke supervenes.
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Affiliation(s)
- Yong Chen
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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110
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Hope SA, Meredith IT. Cellular adhesion molecules and cardiovascular disease. Part I. Their expression and role in atherogenesis. Intern Med J 2003; 33:380-6. [PMID: 12895171 DOI: 10.1046/j.1444-0903.2003.00378.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Atherosclerosis is now recognized to be an inflammatory disease, and several inflammatory markers have been shown to be associated with both the presence and future risk of symptomatic cardiovascular disease. Cellular adhesion molecules, particularly members of the selectin family and immunoglobulin superfamily, are intimately involved in the recruitment of leucocytes to sites of inflammation, including developing atherosclerotic lesions. Their role in the pathogenesis of atherosclerosis has been clearly demonstrated using knockout mice models. Plasma levels of adhesion molecules, which have been shed from the cell surface, have been associated with the presence of clinical atherosclerotic disease, although published studies differ in their findings. This limited consensus in the literature may be explained either by unrecognized confounding factors, or perhaps by the unpredictable relationship between cell surface expression and activity of cellular adhesion molecules and their shedding into the plasma. While cell surface activity of adhesion molecules appears critical in the development of atherosclerotic lesions, the measurement of plasma levels of soluble adhesion molecules may offer little additional benefit for individual patients in the prediction of the extent of atherosclerotic disease above the assessment of conventional cardiovascular risk factors.
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Affiliation(s)
- S A Hope
- Cardiovascular Research Centre, Monash University, Monash Medical Centre, Melbourne, Victoria, Australia
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111
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Hwang YS, Shin CY, Huh Y, Ryu JH. Hwangryun-Hae-Dok-tang (Huanglian-Jie-Du-Tang) extract and its constituents reduce ischemia-reperfusion brain injury and neutrophil infiltration in rats. Life Sci 2002; 71:2105-17. [PMID: 12204769 DOI: 10.1016/s0024-3205(02)01920-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preventive effect of Hwangryun-Hae-Dok-tang (HHDT, Huanglian-Jie-Du-Tang), a Chinese herbal medicine, and its ingredients on ischemia/reperfusion-induced brain injury was evaluated in the rat brain. HHDT consists of four herbs, namely, Coptidis rhizoma, Scutellariae radix, Phellodendri cortex, and Gardeniae fructus. Ischemia was induced by intraluminal occlusion of the right middle cerebral artery for 120 min and reperfusion was continued for 22 h. HHDT (200 mg/kg), Coptidis rhizoma (100 mg/kg), Scutellariae radix (100 mg/kg), Phellodendri cortex (100 mg/kg), and Gardeniae fructus (100 mg/kg) were orally administered, promptly prior to reperfusion and 2 h after reperfusion. Baicalein, a component of Scutellariae radix, was also examined at a dosage of 50 mg/kg given 2 h apart, promptly prior to and 2 h after reperfusion. Total infarction volume in the ipsilateral hemisphere of ischemia/reperfusion rats was significantly lowered by treatment with HHDT, Scutellariae radix, and balicalein. However, the other ingredient of HHDT did not show any ameliorating effects on total infarction volume. The inhibiting effect of Scutellariae radix on total infarction volume was much higher than that of the others. In addition, HHDT, Scutellariae radix, and baicalein significantly inhibited myeloperoxidase (MPO) activity, an index of neutrophil infiltration in ischemic brain tissue at about the same rate (30%). There was marked mismatch between total infarction volume and MPO activity in the Scutellariae radix-treated rats but not in the HHDT- and baicalein-treated groups. Our findings suggest that Scutellariae radix as an ingredient of HHDT plays a crucial protective role in ischemia-induced brain injury. In addition, it is apparent that the effect of Scutellariae radix is the result, in part, of baicalein, a compound contained in Scutellariae radix.
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Affiliation(s)
- Young Sun Hwang
- College of Pharmacy, Kyung Hee University, 1 Hoeki-dong, Dongdeamoon-ku, Seoul 130-701, South Korea
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112
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Abstract
An abundance of experimental data show that inflammation contributes to cerebral ischaemic injury and that attenuation of the inflammatory response can improve outcome. The two clinical trials of therapy aimed at limiting the inflammatory response in acute stroke that have been carried out to date, however, have not shown a benefit to such therapy. The potential reasons for the failure of these trials are discussed.
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Affiliation(s)
- Kyra J Becker
- University of Washington School of Medicine, Seattle, USA.
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113
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Abstract
In experimental models of stroke, inflammation appears to contribute to cerebral ischemic injury. Clinical trials that are aimed at limiting the postischemic inflammatory response, however, have thus far had disappointing results. These clinical failures probably reflect the fact that there has been insufficient preclinical data and inadequate trial design, rather than provide evidence against a role for inflammation in ischemic brain injury.
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Affiliation(s)
- K J Becker
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.
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