UMLS:C0022116 - FACTA Search

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Query: UMLS:C0022116 (ischemia)
91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ischemia-reperfusion brain injury initiates an inflammatory response involving the expression of adhesion molecules and cytokines, some of which are regulated by the nuclear transcription factor NF-kappaB. In this study the authors examined mRNA expression levels for several important genes associated with inflammation at five time points (3, 6, 12, 24, and 72 hours) after transient middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. A sensitive and quantitative technique (TaqMan real-time QRT-PCR) was used to simultaneously measure mRNA levels for key cell adhesion molecules and inflammatory cytokines. Gene expression increased significantly in the injured hemisphere for interleukin (IL)-1beta (12-fold increase at 24 hours), IL-6 (25-fold increase at 6 hours) and ICAM-1 (4-fold increase at 24 hours), and the interhemispheric differences for these genes were significant for every time point examined (P < 0.05 for all values). Tumor necrosis factor-alpha mRNA was upregulated in the injured versus uninjured hemisphere from 3 to 24 hours (5-fold increase at 6 hours), while E-selectin showed a significant increase in mRNA levels from 6 to 24 hours after MCAO (10-fold increase at 6 hours) (P < 0.05 for all values). VCAM-1 mRNA levels did not respond differentially to injury at any time point between the two brain hemispheres. At all time points examined, activated NF-kappaB immunoreactivity was observed in cells throughout the infarct-damaged tissue. These results are consistent with the proinflammatory properties of the induced molecules, which are involved in the initiation of the inflammatory cascade, and may thus contribute to secondary cellular responses that lead to further brain damage.
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PMID:Quantitative real-time RT-PCR analysis of inflammatory gene expression associated with ischemia-reperfusion brain injury. 1221 12

Although inhibiting interaction of beta(2) integrins with cognate immunoglobulin class adhesion receptor ligands is an effective neuroprotective strategy in small mammal models of stroke, the strategy has failed in human trials. A completely different antiadhesion receptor strategy was therefore rigorously tested in a model that may more closely approximate human reperfused stroke. Early leukoadhesive events in postischemic cerebral microvessels are mediated by upregulated selectin-class adhesion receptors on endothelial cells. Therefore, a blocking antibody prepared against common P- and E-selectin epitopes was humanized to suppress complement activation and tested in a reperfused hemispheric stroke model in Papio anubis (baboon). Histological examination of postischemic cerebral microvessels revealed a strong upregulation of E-and P-selectin expression. Placebo-blinded administration of the humanized anti-human E- and P-selectin monoclonal antibody (HuEP5C7, 20 mg/kg IV, n=9; placebo, n=9) immediately after the onset of 1 hour of temporary ischemia resulted in trends showing reduced polymorphonuclear leukocyte (PMN) infiltration into ischemic cortex, reduced infarct volumes (by 41%), improved neurological score (by 35%), and improved ability to self-care (by 39%). Importantly, there was no evidence of systemic complement activation, immune suppression, or pathological coagulopathy associated with this therapy. These data suggest that a humanized anti-E/P-selectin antibody approach is safe and may be effective as a clinical treatment for human stroke.
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PMID:HuEP5C7 as a humanized monoclonal anti-E/P-selectin neurovascular protective strategy in a blinded placebo-controlled trial of nonhuman primate stroke. 1243 35

Prostacyclin is an important endothelial mediator involved in the interaction of neutrophils (PMN) with the vessel wall. Many studies have shown the beneficial effects of prostacyclin in ischemia and reperfusion. However, no previous study has investigated the direct effects of the prostacyclin analogs iloprost (ILO) and alprostadil (PGE(1)) on the endothelial part of the adhesion process. Human umbilical vein endothelial cells (HUVECs) were grown to confluence, stimulated with 300 U/ml TNF-alpha and treated with increasing concentrations of ILO and PGE(1). The cells were washed to remove TNF and the inhibitors and adhesion of fluorescence-green labeled PMN was determined microscopically. ICAM-1, VCAM-1 and E-selectin expression were measured by a cell-surface ELISA. The chemoattractant activity of the endothelial cell releasate was tested in a Boyden chamber.ILO and PGE(1) reduced PMN-adhesion in a concentration-dependent manner (ILO: -54 +/- 9 % at 0.5 microM, PGE1: -46 +/- 10 % at 10 microM). However, the surface expression of ICAM-1, VCAM-1 and E-selectin remained unaltered. When the supernatant of iloprost/PGE(1)-treated cells was transferred onto cells that were activated, but not treated with ILO or PGE(1), the reduction of PMN adhesion remains sustained. These data indicate that the inhibitory effect of ILO/ PGE(1) treatment is achieved by a reduced chemoattractant potential. PAF-antagonists were able to block neutrophil adhesion and mimicked the effect of ILO, while exogenous PAF diminished the inhibitory effect of ILO concentration-dependently. This study demonstrates the beneficial effects of ILO and PGE(1) on inflammatorily activated endothelial cells. These prostacyclin analogs inhibit PMN-adhesion despite maximal adhesion molecule expression by regulating the balance of - yet to be determined - endothelial-derived mediators.
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PMID:Prostacyclin inhibits adhesion of polymorphonuclear leukocytes to human vascular endothelial cells due to adhesion molecule independent regulatory mechanisms. 1249 64

The aim of this study was to quantify the expression of E-selectin, intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vascular endothelial cells (HUVECs) exposed to anoxia/reoxygenation (A/R) in the presence or absence of an inflammatory context (0.1 IU/ml tumor necrosis factor-alpha [TNF-alpha]) and to investigate the effects of two different NADPH inhibitors, apocynin and diphenyleneiodonium (DPI), on the expression of the endothelial cell adhesion molecules. Confluent HUVECs were exposed to anoxia for 3 hours (100% N2), followed by a reoxygenation period of 4 hours. TNF-alpha at 0.1 IU/ml was added to the medium either under normoxic conditions for 7 hours (TNF-alpha) or just before the start of anoxia (A/R + TNF-alpha). Levels of E-selectin, VCAM-1, and ICAM-1 were quantified using specific monoclonal antibodies revealed by an alkaline phosphatase-labeled goat F(ab)'2 fragment against mouse IgG antibody and the fluorescent substrate Attophos. Adhesion experiments were also performed using calcein-labeled U937 leukocytes. HUVECs submitted to A/R overexpressed E-selectin but not VCAM-1 or ICAM-1, whereas TNF-alpha at 0.1 IU/ ml increased the expression of all three adhesion molecules. In endothelial cells subjected to A/R in the presence of TNF-alpha, a synergistic increase of E-selectin expression and a synergistic adhesion of U937 cells was noted. The NADPH oxidase inhibitors apocynin and DPI both decreased significantly the U937 adhesion and the E-selectin overexpression on HUVECs submitted to A/R, TNF-alpha, or A/R + TNF-alpha. These results suggest that E-selectin expression is implicated in the leukocyte adhesion to HUVECs caused by A/R in the presence or absence of an inflammatory context. NADPH oxidase appears to participate in the E-selectin overexpression on HUVECs subjected either to A/R and/or TNF-alpha, suggesting a major role of this enzyme in the ischemia/reperfusion syndrome.
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PMID:Effect of NADPH oxidase inhibition on E-selectin expression induced by concomitant anoxia/reoxygenation and TNF-alpha. 1257 57

Inflammation has been implicated as a secondary injury mechanism following ischemia and stroke. A variety of experimental models, including thromboembolic stroke, focal and global ischemia, have been used to evaluate the importance of inflammation. The vasculature endothelium promotes inflammation through the upregulation of adhesion molecules such as ICAM, E-selectin, and P-selectin that bind to circulating leukocytes and facilitate their migration into the CNS. Once in the CNS, the production of cytotoxic molecules may facilitate cell death. The macrophage and microglial response to injury may either be beneficial by scavenging necrotic debris or detrimental by facilitating cell death in neurons that would otherwise recover. While many studies have tested these hypotheses, the importance of inflammation in these models is inconclusive. This review summarizes data regarding the role of the vasculature, leukocytes, blood-brain barrier, macrophages, and microglia after experimental and clinical stroke.
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PMID:Inflammatory mechanisms after ischemia and stroke. 1257 22

Endothelial nitric oxide synthase (eNOS) phosphorylation increases nitric oxide formation, for example, after VEGF stimulation. We investigated whether nitric oxide formed after overexpression of VEGF or of phosphomimetic eNOS (S1177D) affects PMN-induced myocardial detriment after ischemia and reperfusion. Pigs (n=8 per group) were subjected to percutaneous liposome-based gene transfer by retroinfusion of the anterior interventricular vein 48 h before LAD occlusion (60 min) and reperfusion (24 h). Thereafter, regional myocardial function was assessed as subendocardial segment shortening (SES), and infarct size was determined. Tissue from the infarct region, the noninfarcted area at risk, and a control region was analyzed for NF-kappaB activation (EMSA), tumor necrosis factor (TNF)-alpha, and E-selectin mRNA and infiltration of polymorphonuclear neutrophils (PMN). L-NAME was applied in one group of VEGF-transfected animals. NF-kappaB activition, PMN infiltration in the infarct region, and AAR were reduced after transfection of VEGF or eNOS S1177D, but not after VEGF+L-NAME coapplication. Infarct size decreased, whereas SES improved after either VEGF or eNOS S1177D transfection, an effect inhibited by L-NAME coapplication. Retroinfusion of liposomal VEGF cDNA reduces NF-kappaB-dependent postischemic inflammation and subsequent myocardial reperfusion injury, an effect mediated at least in part by enhanced eNOS phosphorylation.
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PMID:VEGF165 transfection decreases postischemic NF-kappa B-dependent myocardial reperfusion injury in vivo: role of eNOS phosphorylation. 1258 40

Ischemia-reperfusion (IR) of the testis results in germ cell-specific apoptosis and can lead to aspermatogenesis. Germ cell-specific apoptosis after IR of the testis has been shown to be correlated with and dependent on neutrophil recruitment to the testis after IR. Studies that used E-selectin-deficient mice have demonstrated that E-selectin expression is critical for neutrophil recruitment to subtunical venules in the testis after IR and for the resultant germ cell-specific apoptosis. The present study investigates the in vivo signaling pathway that exists after IR that leads to neutrophil recruitment in the murine testis. Mice were subjected to a 2-h period of testicular ischemia followed by reperfusion. Results demonstrate that the proinflammatory cytokines, tumor necrosis factor alpha (TNFalpha) and interleukin 1beta (IL-1beta), are stimulated after IR as is the phosphorylation of c-jun N-terminal kinase (JNK). The downstream transcription factors of JNK, ATF-2 and c-jun are also phosphorylated at specific times after IR of the testis. Activation of the JNK stress-related kinase pathway is correlated with an increase in E-selectin expression and neutrophil recruitment to the testis after IR. Intratesticular injection of IL-1beta also caused JNK phosphorylation and neutrophil recruitment to the testis. These results suggest that testicular IR injury stimulates IL-1beta expression, which leads to activation of the JNK signaling pathway and ultimately E-selectin expression and neutrophil recruitment to the testis. This provides the first evidence of a cytokine/stress-related kinase signaling pathway to E-selectin expression in vivo.
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PMID:Ischemia-reperfusion of the murine testis stimulates the expression of proinflammatory cytokines and activation of c-jun N-terminal kinase in a pathway to E-selectin expression. 1262 Sep 34

In the present study, we used 5-lipoxygenase (5-LO) knockout (KO) mice to evaluate the possible role of 5-LO on the pathogenesis of splanchnic artery occlusion (SAO) shock. SAO shock was induced in mice by clamping both the superior mesenteric artery and the celiac artery for 30 min, followed thereafter by release of the clamp (reperfusion). At 120 min after reperfusion, animals were sacrificed for histological examination and biochemical studies. There was a marked increase in the lipid peroxidation in the ileum as well as in the lung of the SAO-shocked 5-LO wild-type (WT) mice after reperfusion. The absence of 5-LO did not reduce the lipid peroxidation in the intestine or the lung. SAO-shocked WT mice developed a significant increase of tissue (ileum and lung) myeloperoxidase activity and marked histological injury. SAO shock was also associated with a significant mortality (50% survival at 5 h after reperfusion). Reperfused ileum and lung tissue sections from SAO-shocked WT mice showed positive staining for P-selectin, ICAM-1, and E-selectin that was mainly localized in the vascular endothelial cells. The intensity and degree of P-selectin, E-selectin, and ICAM-1 were markedly reduced in tissue section from SAO-shocked 5-LOKO mice. SAO-shocked 5-LOKO mice showed also a significant reduction of the neutrophils infiltration into the reperfused intestine as well as in the lung as evidenced by reduced myeloperoxidase activity, an improved histological status of the reperfused tissues, and an improved survival. Taken together, our results clearly demonstrate that 5-LO plays an important role in ischemia and reperfusion injury and put forward the hypothesis that inhibition of 5-LO may represent a novel and possible strategy in the treatment of ischemia and reperfusion injury. Part of this effect may be due to inhibition of the expression of adhesion molecules and subsequent reduction of neutrophil-mediated cellular injury.
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PMID:5-lipoxygenase knockout mice exhibit a resistance to splanchnic artery occlusion shock. 1292 94

Sickle red cells express adhesion molecules including integrin alpha4beta1, CD36, band 3 protein, sulfated glycolipid, Lutheran protein, phosphatidylserine and integrin-associated protein. The proadhesive sickle cells may bind to endothelial cell P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), CD36 and integrins leading to its activation. Monocytes also activate endothelium by releasing proinflammatory cytokines like tumor necrosis factor alpha (TNF-alpha) and interleukin 1beta (IL-1beta). Sickle monocytes also express increased surface CD11b and cytoplasmic cytokines TNFalpha and IL-1beta indicating activated state. Polymorphonuclear leukocytes (PMNs) are also activated with reduced L-selectin expression, enhanced CD64 expression and elevated levels of sL-selectin, sCD16 and elastase resulting in increased adhesiveness to the endothelium. Platelets are also activated and secrete thrombospondin (TSP) and cytokine IL-1. They also form platelet- monocytes aggregates causing endothelial cell P-selectin expression. Endothelial cell activation by these multiple mechanisms leads to a loss of vascular integrity, expression of leukocyte adhesion molecules, change in the surface phenotype from antithrombotic to prothrombotic, excessive cytokine production and upregulation of HLA molecules. Furthermore, contraction of these activated endothelial cells leads to exposure of extracellular matrix proteins, such as TSP, laminin, and fibronectin and their participation in adhesive interactions with bridging molecules from the plasma such as von Willebrand factor (vWf) released from endothelial cells, ultimately culminating in vasoocclusion and local tissue ischemia, the pathognomonic basis of vasoocclusive crisis.
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PMID:Cytokines in sickle cell disease. 1453 Jan 75

Ischemia and reperfusion of the myocardium initiate an inflammatory response directed against the myocardium, and many studies attribute a significant portion of this injury to leukocytes. Leukocyte and endothelial cell adhesion molecules are responsible for neutrophil-endothelial cell interactions in coronary vasculature following ischemia and reperfusion. Interactions between beta(2)-integrins and intercellular adhesion molecule-1 are responsible for firm adhesion of neutrophils to the coronary endothelium in acute cardiac inflammation. Leukocyte-expressed CD18 plays a crucial role, and genetic deficiency of CD18 significantly attenuates myocardial ischemia-reperfusion injury. Genetic deficiency of intercellular adhesion molecule-1 also minimizes myocardial necrosis following ischemia and reperfusion. The selectin family of adhesion glycoproteins also participates in various phases of leukocyte-endothelial interactions, and studies with P-selectin- and E-selectin-deficient mice have shown attenuation of both neutrophil accumulation and myocardial injury following myocardial ischemia and reperfusion.
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PMID:Leukocyte and endothelial adhesion molecule studies in knockout mice. 1506 59

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