Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Opioids have been shown to confer late preconditioning against ischemia/reperfusion injury in several species. However, it is unknown whether gender or aging affects opioid-induced cardioprotection. Isolated perfused hearts from Fischer 344 rats were subjected to 20 min of global ischemia followed by 20 min of reperfusion. BW373U86, a delta-opioid receptor agonist, was administered s.c. at varying doses (0.1, 0.33, 1.0 mg/kg) 24 h before (BW0.1, BW0.33 and BW1.0, respectively). In 12-week-old male (YM) rats, the recovery of LV developed pressure (LVDP) after ischemia/reperfusion improved significantly in BW0.33 and BW1.0, compared with the control (C). In 78-week-old male (OM) rats, the recovery of LV function after ischemia/reperfusion improved and the total release of CK and LDH during reperfusion was attenuated in BW1.0. In 12-week-old female (YF) rats, the recovery of LV function improved only in BW0.33 but not in BW0.1 and BW1.0. The cardioprotective effect afforded by BW373U86 was completely abolished by NS-398, a COX-2 selective inhibitor, in YM, YF, and OM, although NS-398 in itself did not affect myocardial ischemia/reperfusion injury. The levels of 6-keto-PGF(1alpha) (a stable metabolite of PGI(2)) in coronary effluent during reperfusion were higher in the BW373U86-pretreated group that showed cardioprotection than in C and this increase in PGI(2) production was also inhibited by NS-398 in YM, YF, and OM. In conclusion, BW373U86-induced late preconditioning can be observed in aged and female hearts. A COX-2-dependent increase in PGI(2) production is essential for BW373U86-induced late PC in both sexes and in both young and old rats.
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PMID:Gender and aging do not impair opioid-induced late preconditioning in rats. 1468 5

The cyclooxygenases COX-1 and COX-2 catalyze the first committed step of prostaglandin synthesis from arachidonic acid. Previous studies in rodent stroke models have shown that the inducible COX-2 isoform promotes neuronal injury, and the administration of COX-2 inhibitors reduces infarct volume. We investigated the function of PGE2, a principal prostaglandin product of COX-2 enzymatic activity, in neuronal survival in cerebral ischemia. PGE2 exerts its downstream effects by signaling through a class of four distinct G-protein-coupled EP receptors (for E-prostanoid: EP1, EP2, EP3, and EP4) that have divergent effects on cAMP and phosphoinositol turnover and different anatomical distributions in brain. The EP2 receptor subtype is abundantly expressed in cerebral cortex, striatum, and hippocampus, and is positively coupled to cAMP production. In vitro studies of dispersed neurons and organotypic hippocampal cultures demonstrated that activation of the EP2 receptor was neuroprotective in paradigms of NMDA toxicity and oxygen glucose deprivation. Pharmacologic blockade of EP2 signaling by inhibition of protein kinase A activation reversed this protective effect, suggesting that EP2-mediated neuroprotection is dependent on cAMP signaling. In the middle cerebral artery occlusion-reperfusion model of transient forebrain ischemia, genetic deletion of the EP2 receptor significantly increased cerebral infarction in cerebral cortex and subcortical structures. These studies indicate that activation of the PGE2 EP2 receptor can protect against excitotoxic and anoxic injury in a cAMP-dependent manner. Taken together, these data suggest a novel mechanism of neuroprotection mediated by a dominant PGE2 receptor subtype in brain that may provide a target for therapeutic intervention.
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PMID:Neuroprotective function of the PGE2 EP2 receptor in cerebral ischemia. 1471 58

Mitogen-activated protein kinase (MAPK) pathways transduce signals from a diverse array of extracellular stimuli. The three primary MAPK-signaling pathways are the extracellular regulated kinases (ERK1/2), p38 MAPK, and c-Jun NH(2)-terminal kinase (JNK). Previous research in our laboratory has shown that COX-2-elaborated prostanoids participate in recovery of mucosal barrier function in ischemic-injured porcine ileum. Because COX-2 expression is regulated in part by MAPKs, we postulated that MAPK pathways would play an integral role in recovery of injured mucosa. Porcine mucosa was subjected to 45 min of ischemia, after which tissues were mounted in Ussing chambers, and transepithelial electrical resistance (TER) was monitored as an index of recovery of barrier function. Treatment of tissues with the p38 MAPK inhibitor SB-203580 (0.1 mM) or the ERK1/2 inhibitor PD-98059 (0.1 mM) abolished recovery. Western blot analysis revealed that SB-203580 inhibited upregulation of COX-2 that was observed in untreated ischemic-injured mucosa, whereas PD-98059 had no effect on COX-2 expression. Inhibition of TER recovery by SB-203580 or PD-98059 was overcome by administration of exogenous prostaglandin E(2) (1 microM). The JNK inhibitor SP-600125 (0.1 mM) significantly increased TER and resulted in COX-2 upregulation. COX-2 expression appears to be positively and negatively regulated by the p38 MAPK and the JNK pathways, respectively. Alternatively, ERK1/2 appear to be involved in COX-2-independent reparative events that remain to be defined.
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PMID:Mitogen-activated protein kinases regulate COX-2 and mucosal recovery in ischemic-injured porcine ileum. 1476 49

Polymorphonuclear neutrophils (PMNs) play a critical role in intestinal mucosal injury and repair. To study effects of PMNs on acutely injured mucosa, we applied PMNs isolated from circulation or peritoneal fluid from animals with chemically induced peritonitis to ischemia-injured porcine ileal mucosa. In preliminary experiments, PMNs enhanced recovery of transepithelial electrical resistance (TER), and this action was inhibited by pretreatment with the nonselective cyclooxygenase (COX) inhibitor indomethacin. Because COX-2 is upregulated by inflammatory mediators such as IL-1beta, which is released by PMNs, we postulated that PMNs enhance recovery of ischemia-injured mucosa by a pathway involving IL-1beta and COX-2. Application of 5 x 10(6) PMNs to the serosal surface of ischemia-injured mucosa significantly enhanced recovery of TER (P < 0.05), an effect that was inhibited by the selective COX-2 inhibitor NS-398 (5 microM) and by an IL-1beta receptor antagonist (0.1 mg/ml). Addition of 10 ng/ml IL-1beta to the serosal surface of injured tissues caused a significant increase in TER (P < 0.05) that was inhibited by pretreatment with NS-398. Western blot analysis of mucosal homogenates revealed dramatic upregulation of COX-2 in response to IL-1beta or peritoneal PMNs, and the latter was inhibited by an IL-1beta receptor antagonist. Real-time PCR revealed that increased mRNA COX-2 expression preceded increased COX-2 protein expression in response to IL-1beta. We concluded that PMNs augment recovery of TER in ischemia-injured ileal mucosa via IL-1beta-dependent upregulation of COX-2.
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PMID:Neutrophils augment recovery of porcine ischemia-injured ileal mucosa by an IL-1beta- and COX-2-dependent mechanism. 1501 13

The inflammation model of the isolated hemoperfused bovine uterus was used to introduce a new in vitro model for the investigation of anti-inflammatory substances. As previous studies demonstrated both an increase in PGE2 synthesis and an up-regulation of COX-2 and iNOS mRNA by ischemia-reperfusion injury in the model (Braun and Kietzmann, 2004), inhibitory effects of the glucocorticoid dexamethasone, the NSAID flunixin and the selective COX-2 inhibitor DFU (5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)-phenyl-2-(5H)-furanone) were studied. All substances caused a significant decrease in tissue PGE2 production, while none induced down-regulation of COX-2 mRNA. A slight decrease in the mRNA level of iNOS was observed after 300 minutes of perfusion with dexamethasone-supplemented perfusion medium. In conclusion, the suitability of the isolated hemoperfused bovine uterus for the investigation of anti-inflammatory substances, especially regarding their COX-2 selectivity, was demonstrated. Use of the isolated hemoperfused bovine uterus in pharmacological research and drug screening may contribute to a reduction of animal testing.
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PMID:Ischemia reperfusion injury in the isolated hemoperfused bovine uterus--a model for the investigation of anti-inflammatory substances? 1505 8

Ischemia-reperfusion injury is a microvascular event documented in numerous in vivo animal models. In animal models, prostaglandin and prostaglandin analogues have been found to ameliorate reperfusion injury. These studies were undertaken to evaluate human microvascular endothelial PGE(1) synthesis during in vitro ischemia followed by reperfusion. Human (neonatal) microvascular endothelial cell (MEC) cultures (n = 6) were subjected to sequential 2 h periods of normoxia (20% O(2)), ischemia (1.5% O(2)), and reperfusion (20% O(2)). Prostaglandin E(2) synthesis in conditioned media was determined by ELISA. Steady state levels of MEC prostaglandin H synthase (PGHS)-1 and -2 mRNA were assessed at the end of each 2-h period using RT-PCR and a quantitative mRNA ELISA. MEC PGHS protein levels were analyzed using an ELISA. PGE(1) release increased significantly during the initial 30 min of ischemia, but rapidly fell below normoxic levels by 90 and 120 min. During reperfusion, PGE(1) release returned to normoxic levels at 30, 60, and 90 min, and exceeded normoxic levels at 120 min. PGHS-1 mRNA levels were undetectable during all experimental conditions. PGHS-2 mRNA levels were unchanged by ischemia, but were decreased by reperfusion. In contrast, PGHS-2 protein levels increased 3-fold during ischemia, and remained elevated during reperfusion. Human MEC do not express PGHS-1 mRNA in vitro. Prolonged ischemia decreases MEC PGE(1) synthesis, and stimulates increased PGHS-2 protein levels without altering the steady state levels of COX-2 mRNA. During reperfusion, increased PGHS-2 protein levels persist and are associated with stimulated PGE(2) secretion, despite relative decreases in PGHS-2 mRNA.
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PMID:Human microvascular endothelial cell prostaglandin E1 synthesis during in vitro ischemia-reperfusion. 1515 59

The response of the inducible isoform of the prostaglandin H2 synthase (COX-2) and the c-Jun N-terminal kinase (JNK) in post-ischemic neuronal damage was assessed in a model of ischemic tolerance in Mongolian Gerbils. After a single 6-min bilateral carotid occlusion, histological damage was evident in the CA1 region of hippocampus, correlated with a high expression of JNK and COX-2 mRNA. However, in the group of animals with a 2-min ischemia and the tolerance group, in which a 2-min bilateral carotid occlusion was followed 3 days later by a 6-min ischemia, no hippocampal or cortical damage was detected. Accordingly, the JNK and COX-2 mRNA levels remained unaffected. We suggest that the level of JNK and COX-2 expression may determine the outcome as either post-ischemic cell death or tolerance.
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PMID:Downregulation of COX-2 and JNK expression after induction of ischemic tolerance in the gerbil brain. 1524 55

Angiogenesis is essential for the repair of wounds and tissues damaged by ischemia. The regenerative process is tightly regulated by master angiogenic factors, cytokines and the downstream mediator NO. In addition, modulators of vascular growth, such as COX-2-generated prostanoids, contribute to the process by stabilizing the hypoxia-inducible factor and stimulating the expression of VEGF. Recently, we discovered that human tissue kallikrein, a member of the serine proteinase superfamily, possesses potent angiogenic effects. It has been categorized as a pleiotropic angiogenic agent acting via enzymatic cleavage of kininogen and subsequent release of kinin peptides. Kinins bind G-protein coupled receptors, subtype B1 and B2, and exert proliferative effects on endothelial cells via an IP3K-Akt-NO mediated mechanism independent of VEGF. In addition, kinins stimulate the release of angiogenic prostacyclin. Gene transfer of human tissue kallikrein rescues ischemic tissues in otherwise normal mice, as well as in hypertensive or diabetic animals. In addition, prophylactic gene delivery of tissue kallikrein to diabetic skeletal muscles prevents the development of microangiopathy and stimulates collateralization, thus protecting from the consequences of supervening arterial occlusion.
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PMID:Angiogenesis therapy with human tissue kallikrein for the treatment of ischemic diseases. 1528 43

This study was conducted to determine which isoform of cyclooxygenase (COX) is more significantly involved in the anti-thrombin (AT)-induced increase in prostaglandin production in the liver of rats, subjected to hepatic ischemia/reperfusion (I/R). Hepatic tissue levels of 6-keto-PGF(1alpha), a stable metabolite of prostacyclin (PGI(2)), and PGE(2) were transiently increased 1 hour after reperfusion. Thereafter, hepatic PGE2 levels were gradually increased until 6 hours after reperfusion, while hepatic 6-keto-PGF(1alpha) levels were decreased to the pre-ischemia levels at 6 hours after reperfusion. AT significantly enhanced increases in hepatic tissue levels of 6-keto-PGF(1alpha) and PGE(2) seen 1 hour after reperfusion, while it inhibited increases in hepatic PGE(2) levels seen 6 h after reperfusion. Neither dansyl-Glu-Gly-Arg-chloromethyl ketone-treated factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, nor Trp(49)-modified AT which lacks affinity for heparin, showed any effects on these changes. Pretreatment with indomethacin (IM), a non-selective inhibitor of COX, inhibited AT-induced increases in hepatic tissue levels of 6-keto-PGF(1alpha) and PGE(2) seen 1 hour after reperfusion, whereas pretreatment with NS-398, a selective inhibitor of COX-2, did not. The increase in hepatic tissue blood flow and inhibition of hepatic inflammatory responses seen in animals given AT were reversed by pretreatment with IM, but were not affected by pretreatment with NS-398. Administration of ilo-prost, a stable analog of PGI(2), and PGE(2) produced effects similar to those induced by AT. Increases in hepatic tissue levels of PGE(2) 6 hours after reperfusion were inhibited by pretreatment with NS-398. Although AT did not affect COX-1 mRNA levels 1 hour after reperfusion, it inhibited the I/R-induced increases in hepatic tissue levels of both PGE(2) and COX-2 mRNA 6 hours after reperfusion. These observations strongly suggested that AT might reduce the I/R-induced liver injury by increasing the production of PGI2 and PGE2 through activation of COX-1. Furthermore, since TNF-alpha is capable of inducing COX-2, inhibition of TNF-alpha production by AT might inhibit COX-2-mediated PGE(2) production. These effects induced by AT might contribute to its anti-inflammatory activity.
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PMID:Antithrombin reduces ischemia/reperfusion-induced liver injury in rats by activation of cyclooxygenase-1. 1535 51

Recent studies of ischemia-reperfusion (I/R) injury have focused on the function of neutrophils as well as the actions of inflammatory cytokines. However, few reports address cyclooxygenases (COXs) and lipoxygenases (LOXs). We researched the expression of COXs (COX-1 and COX-2) and LOXs (5-LOX and 12-LOX) in rat renal I/R injury. The right kidney of male Lewis rats was excised, and the left renal artery and vein clamped for a 90-minute ischemia time. Rats were humanely killed at 0, 1.5, 3, 5, and 12 hours after reperfusion. COX and LOX expressions were studied using immunohistostaining. COX-2 and LOX expressions were observed only on endothelial cells of normal kidney. From 1.5 to 5 hours after reperfusion, COX-2 and LOXs expressions gradually intensified on endothelial cells. COX-2 and LOXs expression were most intense on endothelial cells at 5 hours after reperfusion. Twelve hours after reperfusion, necrosis extended throughout the ischemic kidney and nearly all the tubular epithelial cells were destroyed. Thus, at 12 hours after reperfusion, COX-2 and LOXs expressions on endothelial cells became weaker. However, COX-1 expression was not different at every time after reperfusion. COX-2 and LOXs were expressed in a rat model showing renal I/R injury. Several hours after the maximum of COX-2 and LOXs expressions, the maximal renal I/R injury was observed. These results suggest a relationship between COX-2 and LOXs expressions and renal I/R injury.
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PMID:The expression of cyclooxygenases and lipoxygenases in renal ischemia-reperfusion injury. 1551 5


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