Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917798 (cerebral ischemia)
 17,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, erythropoietin was shown to have both hematopoietic as well as tissue-protective properties. Erythropoietin (EPO) had a protective effect in animal models of cerebral ischemia, mechanical trauma of the nervous system, myocardial infarction, and ischemia-reperfusion (I/R) injury of the kidney. It is not known whether EPO protects the liver against I/R injury. Using a rat model of liver I/R injury, we aimed to determine the effect of the administration of human recombinant erythropoietin (rhEPO) on liver injury. Rats were subjected to 30 min of liver ischemia followed by 2 h of reperfusion. When compared with the sham-operated rats, I/R resulted in significant rises in the serum levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, gamma-glutamyl transferase, tissue lipid peroxidation, caspase-3 activity and altered histology. Administration of rhEPO 5 min before ischemia was able to reduce the biochemical evidence of liver injury; however, this protection was not evident when rhEPO was administered 5 min before reperfusion. Mechanistically, early administration of rhEPO was able to reduce the oxidative stress and caspase-3 activation, suggesting the subsequent reduction of apoptosis. This study provides the first evidence that rhEPO causes a substantial reduction of the liver injury induced by I/R in the rat.
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PMID:Recombinant human erythropoietin protects the liver from hepatic ischemia-reperfusion injury in the rat. 1701 28

Global and focal cerebral ischemia is followed by a secondary damage characterized by oxidative stress, excitotoxicity, inflammation and apoptosis. Erythropoietin (EPO) exerts antiapoptotic, anti-inflammatory, antioxidative, angiogenetic and neurotrophic properties. Its potential therapeutic role has been demonstrated in several animal models of cerebral ischemia and also in a clinical trial of ischemic stroke, so it could be considered an ideal compound for neuroprotection in ischemic stroke and in cardiac arrest. Intracerebral hemorrhage (ICH) is the least treatable form of stroke; the mechanisms involved in the secondary brain injury include hematoma mass effect, neuronal apoptosis and necrosis, inflammation. It has been demonstrated in an experimental ICH that EPO intervenes in the inflammatory process, reduces brain water content, hemorrhage volume and hemispheric atrophy, promotes cell survival, preserves cerebral blood flow, has antiapoptotic protective function against oxidative stress and excitotoxic damage. EPO can attenuate acute vasoconstriction and prevent brain ischemic damage in subarachnoid hemorrhage. The neuroprotective function of EPO has been studied also in traumatic brain injury: it reduces the inflammation and improves cognitive and motor deficits. The authors review some of the physiological actions of EPO in the physiopathology of ischemic and hemorrhagic stroke, subarachnoid hemorrhage and brain trauma, and its potential usefulness in the brain injured patient management.
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PMID:The use of erythtropoietin in cerebral diseases. 1860 42

Erythropoietin (EPO) has shown promise as a neuroprotectant in animal models of ischemic stroke. EPO is thought not only to protect neurons from cell death, but also to promote regeneration after stroke. Here, we report a systematic review and meta-analysis of the efficacy of EPO in animal models of focal cerebral ischemia. Primary outcomes were infarct size and neurobehavioral outcome. Nineteen studies involving 346 animals for infarct size and 425 animals for neurobehavioral outcome met our inclusion criteria. Erythropoietin improved infarct size by 30.0% (95% CI: 21.3 to 38.8) and neurobehavioral outcome by 39.8% (33.7 to 45.9). Studies that randomized to treatment group or that blinded assessment of outcome showed lower efficacy. Erythropoietin was tested in animals with hypertension in no studies reporting infarct size and in 7.5% of the animals reporting neurobehavioral outcome. These findings show efficacy for EPO in experimental stroke, but when the impact of common sources of bias are considered, this efficacy falls, suggesting we may be overestimating its potential benefit. As common human co-morbidities may reduce therapeutic efficacy, broader testing to delineate the range of circumstances in which EPO works best would be beneficial.
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PMID:A systematic review and meta-analysis of erythropoietin in experimental stroke. 2004 Sep 29

Delayed cerebral ischemia after subarachnoid hemorrhage (SAH) may be affected by a number of factors, including cerebral blood flow and oxygen delivery. Anemia affects about half of patients with SAH and is associated with worse outcome. Anemia also may contribute to the development of or exacerbate delayed cerebral ischemia. This review was designed to examine the prevalence and impact of anemia in patients with SAH and to evaluate the effects of transfusion. A literature search was made to identify original research on anemia and transfusion in SAH patients. A total of 27 articles were identified that addressed the effects of red blood cell transfusion (RBCT) on brain physiology, anemia in SAH, and clinical management with RBCT or erythropoietin. Most studies provided retrospectively analyzed data of very low-quality according to the GRADE criteria. While RBCT can have beneficial effects on brain physiology, RBCT may be associated with medical complications, infection, vasospasm, and poor outcome after SAH. The effects may vary with disease severity or the presence of vasospasm, but it remains unclear whether RBCTs are a marker of disease severity or a cause of worse outcome. Erythropoietin data are limited. The literature review further suggests that the results of the Transfusion Requirements in Critical Care Trial and subsequent observational studies on RBCT in general critical care do not apply to SAH patients and that randomized trials to address the role of RBCT in SAH are required.
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PMID:Anemia and transfusion after subarachnoid hemorrhage. 2176 59

The most common cause of stroke is cerebral ischemia, where blood flow to the brain is interrupted due to a thrombus in a major cerebral artery. Currently, the only therapeutic approach available is thrombolysis. A more recent approach that has started to gain attention is neuroprotection, the ability to prevent neuronal death and enhance endogenous protective mechanisms. Several studies have shown the neuroprotective action of Erythropoietin (EPO). A potential problem in the use of EPO for neurodegenerative disorders is the undesirable erythropoietic side effects. In this context, investigations have been focused to develop derivatives of EPO lacking erythropoietic activity but retaining neuroprotective potential. Low sialic acid-containing EPO (Neuro EPO) is very similar to the one that occurs in the mammalian brain and is rapidly degraded by the liver. Similar neuroprotective effects had been observed with neuro EPO, original recombinant human EPO and EPO variants in ischemia models. Intranasal route could be safe and hematological side effects could be avoided. Neuro EPO that constitutes a new agent has retained the neuroprotective effects without stimulating the EPOR in the bone marrow and can therefore be used without increasing the hematocrit. This review gives a brief introduction to the no hematopoietic effects of EPO, the evidence of neuroprotective effect, the alternatives for obtaining an EPO derivate without hematological side effects and discusses the advantages of nasal administration of Neuro EPO for neuroprotective stroke treatment.
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PMID:Nasal neuro EPO could be a reliable choice for neuroprotective stroke treatment. 2237 76

Erythropoietin (EPO) is a neuroprotective cytokine in models of ischemic and nervous system injury, where it reduces neuronal apoptosis and inflammatory cytokines and increases neurogenesis and angiogenesis. EPO also improves cognition in healthy volunteers and schizophrenic patients. We studied the effect of EPO administration on the gene-expression profile in the ischemic cortex of rats after cerebral ischemia at early time points (2 and 6 h). EPO treatment up-regulated genes already increased by ischemia. Hierarchical clustering and analysis of overrepresented functional categories identified genes implicated in synaptic plasticity-Arc, BDNF, Egr1, and Egr2, of which Egr2 was the most significantly regulated. Up-regulation of Arc, BDNF, Dusp5, Egr1, Egr2, Egr4, and Nr4a3 was confirmed by quantitative PCR. We investigated the up-regulation of Egr2/Krox20 further because of its role in neuronal plasticity. Its elevation by EPO was confirmed in an independent in vivo experiment of cerebral ischemia in rats. Using the rat neuroblastoma B104, we found that wild-type cells that do not express EPO receptor (EPOR) do not respond to EPO by inducing Egr2. However, EPOR-expressing B104 cells induce Egr2 early upon incubation with EPO, indicating that Egr2 induction is a direct effect of EPO and that EPOR mediates this effect. Because these changes occur in vivo before decreased inflammatory cytokines or neuronal apoptosis is evident, these findings provide a molecular mechanism for the neuroreparative effects of cytokines and suggest a mechanism of neuroprotection by which promotion of a plastic phenotype results in decreased inflammation and neuronal death.
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PMID:Erythropoietin-induced changes in brain gene expression reveal induction of synaptic plasticity genes in experimental stroke. 2264 29

Erythropoietin (EPO) is a neuroprotective agent against cerebral ischemia/reperfusion (I/R)-induced brain injury. However, its crossing of blood-brain barrier is limited. Focused ultrasound (FUS) sonication with microbubbles (MBs) can effectively open blood-brain barrier to boost the vascular permeability. In this study, we investigated the effects of MBs/FUS on extending the therapeutic time window of EPO and its neuroprotective effects in both acute and chronic phases. Male Wistar rats were firstly subjected to two common carotid arteries and right middle cerebral artery occlusion (three vessels occlusion, 3VO) for 50 min, and then the rats were treated with hEPO (human recombinant EPO, 5000 IU/kg) with or without MBs/FUS at 5 h after occlusion/reperfusion. Acute phase investigation (I/R, I/R+MBs/FUS, I/R+hEPO, and I/R+hEPO+MBs/FUS) was performed 24 h after I/R; chronic tests including cylinder test and gait analysis were performed one month after I/R. The experimental results showed that MBs/FUS significantly increased the cerebral content of EPO by bettering vascular permeability. In acute phase, both significant improvement of neurological score and reduction of infarct volume were found in the I/R+hEPO+MBs/FUS group, as compared with I/R and I/R+hEPO groups. In chronic phase, long-term behavioral recovery and neuronal loss in brain cortex after I/R injury was significantly improved in the I/R+hEPO+MBs/FUS group. This study indicates that hEPO administration with MBs/FUS sonication even at 5 h after occlusion/reperfusion can produce a significant neuroprotection.
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PMID:Targeted delivery of erythropoietin by transcranial focused ultrasound for neuroprotection against ischemia/reperfusion-induced neuronal injury: a long-term and short-term study. 2458 28

Subarachnoid haemorrhage (SAH) caused by a ruptured aneurysm accounts for only 5 % of strokes, but occurs at a fairly young age and carries a poor prognosis. Delayed cerebral ischaemia (DCI) is an important cause of death and dependence after aneurysmal SAH. The current mainstay of preventing DCI is nimodipine and maintenance of normovolemia, but even with this strategy DCI occurs in a considerable proportion of patients.Several drugs have been developed that have the potential to limit cerebral vasospasm and delayed ischaemic neurologic deficit, thus improving outcome for patients. However, although numerous agents can prevent arterial narrowing and/or block the excitatory cascade of events leading to ischaemic neuronal death in experimental conditions, there is still no pharmacologic agent that has been shown conclusively to improve the outcome in clinical practice.Erythropoietin (EPO) is a well-known erythropoietic hormone recently found to exert neuroprotective properties and has been shown to reduce cerebral vasospasm and infarct volume after experimental SAH. In humans, although EPO treatment did not impact the overall incidence of vasospasm, it significantly reduced the incidence of severe vasospasm, the incidence of delayed ischaemic deficits with new cerebral infarcts, and the duration of impaired autoregulation. The current study provides new evidence for the potential benefit and relative safety of EPO for the treatment of SAH in humans. Future clinical trials will hopefully provide definite evidence whether EPO treatment is beneficial in SAH patients.
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PMID:The role of erythropoietin in aneurysmal subarachnoid haemorrhage: from bench to bedside. 2536 3

Erythropoietin (EPO) has protective effects on many neurological diseases, including cerebral ischemia. Here, we aimed to test EPO's effects on ischemic neurovascular unit (NVU) injuries and examine whether the effects were dependent on connexin43 (Cx43) mediated gap junctional intercellular communication (GJIC). We detected the expression of Cx43 and phosphorylation of Cx43 (p-Cx43) at 1 d, 3 d, and 7 d after middle cerebral artery occlusion (MCAO). Meanwhile, we examined the effects of EPO on NVU injuries including neuronal survival, astrocyte activation and regeneration of endothelial cells as well as whether the effects were Cx43 dependent by using multiple inhibitors. We found EPO highly increased p-Cx43, but not total Cx43 at all chosen times. Importantly, EPO led to neurological and blood-brain barrier functions improvement by associating with promotion of angiogenesis as well as reduction of neuronal death, astrocyte activation and neurotoxic substances levels. Moreover, these effects were significantly weakened by the inhibitors blocking GJIC, Cx43 communicative function, phosphorylation and expression, only Cx43 redistribution inhibitor excluded. Our data suggest the protective effects of EPO on NUV injuries are highly associated with the increase of p-Cx43, which improves GJIC to reduce neurotoxic substances.
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PMID:Protection of erythropoietin against ischemic neurovascular unit injuries through the effects of connexin43. 2568 87

Erythropoietin (EPO) promotes oligodendrogenesis and attenuates white matter injury in neonatal rats. However, it is unknown whether this effect extends to adult mice and whether EPO regulate microglia polarization after ischemic stroke. Male adult C57BL/6 mice (25-30g) were subjected to 45 min of middle cerebral artery occlusion (MCAO). EPO (5000 IU/kg) or saline was injected intraperitoneally every other day after reperfusion. Neurological function was evaluated using the rotarod test at 1, 3, 7 and 14 days after MCAO. Brain tissue loss volume was determined by hematoxylin-eosin staining. Immunofluorescence staining and Western blot were also used to assess the severity of white matter injury and phenotypic changes in microglia/macrophages. Bromodeoxyuridine (BrdU) was injected intraperitoneally daily for 1 week to analyze the number of newly proliferating glia cells (oligodendrocytes, microglia, and astrocytes). We found that EPO significantly reduced Brain tissue loss volume, ameliorated white matter injury, and improved neurobehavioral outcomes at 14 days after MCAO (P<0.05). In addition, EPO also increased the number of newly generated oligodendrocytes and attenuated the rapid hypertrophy and hyperplasia of microglia and astrocytes after ischemic stroke (P<0.05). Furthermore, EPO reduced M1 microglia and increased M2 microglia (P<0.05). Taken together, our results suggest that EPO treatment improves white matter integrity after cerebral ischemia, which could be attributed to EPO attenuating gliosis and facilitating the microglial polarization toward the beneficial M2 phenotype to promote oligodendrogenesis.
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PMID:Effects of Erythropoietin on Gliogenesis during Cerebral Ischemic/Reperfusion Recovery in Adult Mice. 2884 56


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