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)

Many natural polyphenolic compounds have been shown to attenuate reactive oxygen/nitrogen species (ROS/RNS) formation and protect against ischemia/reperfusion injury both in vitro and in vivo. 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (TSG), an active component of the rhizome extract from Polygonum multiflorum, exhibits antioxidative and anti-inflammatory effects. Here, we used an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD-R) and an in vivo ischemic model of middle cerebral artery occlusion (MCAO) to investigate the neuroprotective effects of TSG on ischemia/reperfusion brain injury and the related mechanisms. We demonstrated that OGD-R-induced neuronal injury, intracellular ROS generation, and mitochondrial membrane potential dissipation were reversed by TSG. The elevation of H2O2-induced [Ca2+]i was also attenuated by TSG. Inhibition of the c-Jun N-terminal kinase (JNK) and Bcl-2 family-related apoptotic signaling pathway was involved in the neuroprotection afforded by TSG. Meanwhile, TSG inhibited iNOS mRNA expression induced by OGD-R, which may be mediated by the activation of SIRT1 and inhibition of NF-kappaB activation. In vivo studies further demonstrated that TSG significantly reduced the brain infarct volume and the number of positive cells by TUNEL staining in the cerebral cortex compared to the MCAO group. Our study indicates that TSG protects against cerebral ischemia/reperfusion injury through multifunctional cytoprotective pathways.
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PMID:Protection by tetrahydroxystilbene glucoside against cerebral ischemia: involvement of JNK, SIRT1, and NF-kappaB pathways and inhibition of intracellular ROS/RNS generation. 1927 42

Cardiolipin is a unique phospholipid which is almost exclusively located at the level of the inner mitochondrial membrane where it is biosynthesized. This phospholipid is known to be intimately involved in several mitochondrial bioenergetic processes. In addition, cardiolipin also has active roles in several of the mitochondrial-dependent steps of apoptosis and in mitochondrial membrane dynamics. Alterations in cardiolipin structure, content and acyl chains composition have been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions, including ischemia/reperfusion, different thyroid states, diabetes, aging and heart failure. Cardiolipin is particularly susceptible to ROS attack due to its high content of unsaturated fatty acids. Oxidative damage to cardiolipin would negatively impact the biochemical function of the mitochondrial membranes altering membrane fluidity, ion permeability, structure and function of components of the mitochondrial electron transport chain, resulting in reduced mitochondrial oxidative phosphorylation efficiency and apoptosis. Diseases in which mitochondrial dysfunction has been linked to cardiolipin peroxidation are described. Ca(2+), particularly at high concentrations, appears to have several negative effects on mitochondrial function, some of these effects being linked to CL peroxidation. Cardiolipin peroxidation has been shown to participate, together with Ca(2+), in mitochondrial permeability transition. In this review, we provide an overview of the role of CL peroxidation and Ca(2+) in mitochondrial dysfunction and disease.
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PMID:Role of cardiolipin peroxidation and Ca2+ in mitochondrial dysfunction and disease. 1936 71

ERK1/2 has been reported to be activated in the postischemic kidney but its precise role in ischemia/reperfusion (I/R) injury remains unclear. Therefore, we have studied the expression of ERK1/2 and its contribution to cytoskeleton organization and cell adhesion structures in proximal tubular cells, all affected during I/R. We observe ERK1/2 activation at 24 hours of reperfusion in an in vivo model of I/R, when acute tubular necrosis (ATN) is most prominent. In addition, by means of an in vitro model of hypoxia/reoxygenation (H/R) in rat proximal NRK-52E cells we show that p-ERK1/2 is strongly induced early during reoxygenation. Moreover, we also demonstrate that ROS generation contributed to this induction. ERK1/2 activation is contemporary with cell-cell adhesion disruption during reoxygenation but the use of U0126 did not have effect on adherens junctions (AJ) and tight junctions (TJ) disassembly, neither on epithelial monolayer permeability. On the contrary, ERK1/2 affects cytoskeleton organization and focal complexes assembly during H/R, since U0126 improved actin and tubulin cytoskeleton structure, reduced cell contraction and prevented paxillin redistribution. In summary, ERK1/2 signalling plays an essential role in I/R induced injury, mediating proximal cell adhesive alterations which lead to tubular damage and ultimately might compromise renal function.
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PMID:ERK1/2 mediates cytoskeleton and focal adhesion impairment in proximal epithelial cells after renal ischemia. 1947 Oct 96

Neurons are highly dependent on astrocyte survival during brain damage. To identify genes involved in astrocyte function during ischemia, we performed mRNA differential display in astrocytes after oxygen and glucose deprivation (OGD). We detected a robust down-regulation of S6 kinase 1 (S6K1) mRNA that was accompanied by a sharp decrease in protein levels and activity. OGD-induced apoptosis was increased by the combined deletion of S6K1 and S6K2 genes, as well as by treatment with rapamycin that inhibits S6K1 activity by acting on the upstream regulator mTOR (mammalian target of rapamycin). Astrocytes lacking S6K1 and S6K2 (S6K1;S6K2-/-) displayed a defect in BAD phosphorylation and in the expression of the anti-apoptotic factors Bcl-2 and Bcl-xL. Furthermore reactive oxygen species were increased while translation recovery was impaired in S6K-deficient astrocytes following OGD. Rescue of either S6K1 or S6K2 expression by adenoviral infection revealed that protective functions were specifically mediated by S6K1, because this isoform selectively promoted resistance to OGD and reduction of ROS levels. Finally, "in vivo" effects of S6K suppression were analyzed in the permanent middle cerebral artery occlusion model of ischemia, in which absence of S6K expression increased mortality and infarct volume. In summary, this article uncovers a protective role for astrocyte S6K1 against brain ischemia, indicating a functional pathway that senses nutrient and oxygen levels and may be beneficial for neuronal survival.
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PMID:mTOR/S6 kinase pathway contributes to astrocyte survival during ischemia. 1953 30

Myocardial injury due to ischemia-reperfusion (I-R) damage remains a major clinical challenge. Its pathogenesis is complex including endothelial dysfunction and heightened oxidative stress although the key driving mechanism remains uncertain. In this study we tested the hypothesis that the I-R process induces a state of insufficient L-arginine availability for NO biosynthesis, and that this is pivotal in the development of myocardial I-R damage. In neonatal rat ventricular cardiomyocytes (NVCM), hypoxia-reoxygenation significantly decreased L-arginine uptake and NO production (42 +/- 2% and 71 +/- 4%, respectively, both P < 0.01), maximal after 2 h reoxygenation. In parallel, mitochondrial membrane potential significantly decreased and ROS production increased (both P < 0.01). NVCMs infected with adenovirus expressing the L-arginine transporter, CAT1, and NVCMs supplemented with L-arginine both exhibited significant (all P < 0.05) improvements in NO generation and mitochondrial membrane potentials, with a concomitant significant fall in ROS production and lactate dehydrogenase release during hypoxia-reoxygenation. In contrast, L-arginine deprived NVCM had significantly worsened responses to hypoxia-reoxygenation. In isolated perfused mouse hearts, L-arginine infusion during reperfusion significantly improved left ventricular function after I-R. These improved contractile responses were not dependent on coronary flow but were associated with a significant decrease in nitrotyrosine formation and increases in phosphorylation of both Akt and troponin I. Collectively, these data strongly implicate reduced L-arginine availability as a key factor in the pathogenesis of I-R injury. Increasing L-arginine availability via increased CAT1 expression or by supplementation improves myocardial responses to I-R. Restoration of L-arginine availability may therefore be a valuable strategy to ameliorate I-R injury.
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PMID:Reduced L-arginine transport contributes to the pathogenesis of myocardial ischemia-reperfusion injury. 1954 85

The aim of this work was to investigate the cardioprotective activity of hydrolysable gallotannins from Rhus coriaria L. leaves extract (RCLE) in isolated rabbit heart preparations, submitted to low-flow ischemia/reperfusion damage. RCLE induces a dose-dependent normalization of coronary perfusion pressure (CPP), reducing left ventricular contracture during ischemia, and improving left ventricular developed pressure and the maximum rate of rise and fall of left ventricular pressure at reperfusion. Creatinine kinase (CK) and lactate dehydrogenase (LDH) outflow were significantly reduced during reperfusion. In parallel there was a rise in the release of the cytoprotective 6-ketoprostaglandin F (1alpha) (6-keto-PGF (1alpha)) and a decrease of tumor necrosis factor-alpha (TNF-alpha), both significant only at the highest RCLE concentrations (150-500 microg/mL). The vasorelaxant activity of RCLE was studied in isolated rabbit aorta rings precontracted with norepinephrine (NE) with and without endothelium. The vasorelaxation induced by RCLE was predominantly endothelium-dependent as demonstrated by the loss of RCLE vasorelaxant ability in i) de-endothelized rings and ii) in intact aortic rings after pretreatment with NG-monomethyl- L-arginine (L-NMMA) and 1 H-[1.2.4]oxadiazolo[4.3- A]quinoxalin-1-one (ODQ). The inhibition of vasorelaxation in intact rings by indomethacin (INDO) demonstrates the ability of RCLE to modulate the coronary endothelium cyclooxygenase (COX) pathway. The K-ATP channel antagonist glibenclamide (GLIB) was ineffective. The antioxidant activity of RCLE, investigated in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) model and in living cell systems (rat erythrocytes), was stronger than that of gallic acid, ascorbic acid and trolox. The structure of its main bioactive constituents, profiled by HPLC-ESI-HR-S, comprised a mixture of polygalloylated D-glucopyranose with different degrees of galloylation and 3- O-methylgallic acid. The cardiovascular protective effect of RCLE seems to be due to an interplay of different factors: COX pathway activation, TNF-alpha inhibition, endothelial nitric oxide synthase (eNOS) activation, and free radical and ROS scavenging.
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PMID:Anti-ischemic activity and endothelium-dependent vasorelaxant effect of hydrolysable tannins from the leaves of Rhus coriaria (Sumac) in isolated rabbit heart and thoracic aorta. 1954 91

It has been shown that NAD(+) availability is important for neuronal survival following ischemia (Liu et al., Neuromolecular Med 11:28-42, 2009). It is proposed here that NAD(+) may also control proteotoxicity by influencing both formation and catabolism of altered proteins. It is suggested that low NAD(+) availability promotes synthesis of methylglyoxal (MG) which can induce formation of glycated proteins, ROS, and dysfunctional mitochondria. That glyoxalase overexpression and carnosine are both protective against MG and ischemic injury support this proposal. Recognition and elimination of altered proteins is enhanced by NAD(+) through effects on stress protein expression and autophagy.
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PMID:NAD+ availability and proteotoxicity. 1955 82

Dysregulation of Ca(2+) has long been implicated to be important in cell injury. A Ca(2+)-linked process important in necrosis and apoptosis (or necrapoptosis) is the mitochondrial permeability transition (MPT). In the MPT, large conductance permeability transition (PT) pores open that make the mitochondrial inner membrane abruptly permeable to solutes up to 1500 Da. The importance of Ca(2+) in MPT induction varies with circumstance. Ca(2+) overload is sufficient to induce the MPT. By contrast after ischemia-reperfusion to cardiac myocytes, Ca(2+) overload is the consequence of bioenergetic failure after the MPT rather than its cause. In other models, such as cytotoxicity from Reye-related agents and storage-reperfusion injury to liver grafts, Ca(2+) appears to be permissive to MPT onset. Lastly in oxidative stress, increased mitochondrial Ca(2+) and ROS generation act synergistically to produce the MPT and cell death. Thus, the exact role of Ca(2+) for inducing the MPT and cell death depends on the particular biologic setting.
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PMID:Mitochondrial calcium and the permeability transition in cell death. 1957 66

Programmed necrosis is a mechanism of cell death that has been described for neuronal excitotoxicity and ischemia/reperfusion injury, but has not been extensively studied in the context of exposure to bacterial exotoxins. The alpha-toxin of Clostridium septicum is a beta-barrel pore-forming toxin and a potent cytotoxin; however, the mechanism by which it induces cell death has not been elucidated in detail. We report that alpha-toxin formed Ca(2+)-permeable pores in murine myoblast cells, leading to an increase in intracellular Ca(2+) levels. This Ca(2+) influx did not induce apoptosis, as has been described for other small pore-forming toxins, but a cascade of events consistent with programmed necrosis. Ca(2+) influx was associated with calpain activation and release of cathepsins from lysosomes. We also observed deregulation of mitochondrial activity, leading to increased ROS levels, and dramatically reduced levels of ATP. Finally, the immunostimulatory histone binding protein HMGB1 was found to be released from the nuclei of alpha-toxin-treated cells. Collectively, these data show that alpha-toxin initiates a multifaceted necrotic cell death response that is consistent with its essential role in C. septicum-mediated myonecrosis and sepsis. We postulate that cellular intoxication with pore-forming toxins may be a major mechanism by which programmed necrosis is induced.
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PMID:Programmed cellular necrosis mediated by the pore-forming alpha-toxin from Clostridium septicum. 1960 57

Although the mitochondrial permeability transition pore (mPTP) was first discovered almost 30 years ago [1], it did not attract significant research attention until the 1990's when several studies implicated mPTP in apoptosis [2]. Today, the dogma suggests that opening of mPTP is detrimental to the cell and mPTP activation is widely thought to contribute to disease in cancer, neurodegenerative diseases, stroke, muscular dystrophy, and cardiac reperfusion injury [3]. Multiple factors including Ca(2+), OH(-), P(i), cyclophilin D, reactive oxygen and nitrogen species (ROS and RNS) trigger mPTP opening [4]. However, whether mPTP activation feeds back to alter mitochondrial ROS generation remains unclear. We recently demonstrated that under normal conditions, individual mitochondria undergo spontaneous transient bursts of quantal superoxide generation, termed "superoxide flashes" [5]. Superoxide flashes are observed in all cell types investigated to date and are triggered by a surprising functional coupling between mPTP activation and electron transport chain (ETC) dependent superoxide production. Additionally, reoxgenation following anoxia leads to uncontrolled superoxide flash genesis in cardiomyocytes. This positive feedback mechanism for mPTP/ETC-dependent ROS generation may drive localized redox signaling in individual mitochondria under physiological conditions, and when left unchecked, contribute to global cellular oxidative stress under pathological conditions in cardiac disease. The mPTP activity-dependent cell life and death determination imposes new challenges and opportunities in the pursuit of therapeutic agents for treating diseases in which oxidative stress has been implicated such as cardiac ischemia-reperfusion injury.
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PMID:Superoxide flashes: illuminating new insights into cardiac ischemia/reperfusion injury. 1964 73


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