losartan-potassium and Cerebral-Infarction

Erythropoietin, a hematopoietic growth-factor possessing manifold, potent neuroprotective properties, after multiple testing in cell culture and animal studies now gradually finds its way into clinical neuroscience. The first time this took place was in 1998 with a pilot study in stroke patients, the "Göttingen EPO-Stroke-Trial". This study was able to demonstrate that EPO is perfectly well tolerated and safe with this indication. Furthermore, the EPO-treated patients showed a significantly better outcome regarding their clinical progress as well as regarding the infarct size as observed by MRI, when compared to the placebo treated patients. At the moment a multicenter study is being carried out in Germany.

Topics: Anemia; Brain Ischemia; Cerebral Infarction; Clinical Trials as Topic; Erythropoietin; Hematinics; Humans; Hypoxia, Brain; Pilot Projects; Safety; Treatment Outcome

Within the hippocampus, the CA1 and dentate gyrus (DG) regions are considered the most and the least susceptible to damage by cerebral ischemia, respectively. In addition, it has been tested that rHuEPO exhibits neuroprotective properties. This work investigates the effect of different intranasal doses of rHuEPO, applied in different ischemic post-damage times in the DG, and the effect of the rHuEPO on astroglial reactivity after cerebral ischemia. Additionally, an effective dose for neuroprotection and an administration time was used to evaluate gene and protein expression changes of EPO and EPOR in the DG region. We observed a considerable loss of cells on the granular layer and an increased number of GFAP immunoreactive cells in this region only 72 h after the onset of ischemia/damage. When rHuEPO was administered, the number of morphologically abnormal cells and immunoreactivity decreased. In the analysis of protein and gene expression, there is no correlation between expression level of these molecules, although the rHuEPO amplifies the response to ischemia of EPO and EPOR gene for each evaluated time; in the case of the protein only at 2 h this effect was observed. We demonstrated the susceptibility of the DG to ischemia; so granular cells damage was observed, moreover of the astrocytic response, which is accompanied by molecular changes in signaling mediated by rHuEPO intranasal administration.

Topics: Administration, Intranasal; Brain Ischemia; Cerebral Infarction; Dentate Gyrus; Erythropoietin; Gliosis; Humans

In patients with acute symptomatic moyamoya (<2 weeks), the feasibility of a combination therapy of multiple burr hole procedure under local anesthesia and intravenous erythropoietin pretreatment was assessed. We also identified the factors associated with transdural revascularization.. In this prospective single-arm study, perfusion-impaired patients presenting with transient ischemic attack or acute cerebral infarction were assessed. Combination therapy was performed to patients lacking transdural collaterals. Primary outcomes were evaluated clinically with modified Rankin Scale scores and radiologically with revascularization success (transhemispheric, trans-burr hole, and sufficient revascularizations [filling ≥33% of ipsilateral supratentorium]) at 6 months. Treatment-related adverse events were analyzed in 3 phases: pre burr hole, post burr hole, and after-discharge as secondary outcome. Factors associated with sufficient revascularization were investigated.. Fifty hemispheres from 37 patients were included. Compared with discharge, modified Rankin Scale score at 6 months significantly improved (2.0 [0.0-5.0] versus 1.0 [0.0-4.0];. Combination therapy allows safe and effective revascularization in moyamoya patients with acute ischemic presentation.. URL: https://www.clinicaltrials.gov. Unique identifier: NCT03162588.

Topics: Acute Disease; Adult; Cerebral Infarction; Cerebral Revascularization; Combined Modality Therapy; Erythropoietin; Feasibility Studies; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Moyamoya Disease; Odds Ratio; Prospective Studies; Trephining

Erythropoietin (EPO), as a type of the tissue-protective cytokines, is a 30.4 kDa hematopoietic glycoprotein. The purpose of this study was to explore the neuroprotective effects of EPO on the neonatal hypoxic-ischemic-induced hippocampus injury and the MMP-2 expression.. Neonatal Sprague-Dawley (SD) rats were randomly divided into an untreated group (control) and two hypoxia-ischemia (HI) groups treated with saline control or EPO. Hippocampi were harvested at various times after return to normoxia (6 h, 24 h, 3 days and 7 days post-HI) for analyses of infarct areas and expression using histology, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR).. EPO injections reduced the infarction and loss of brain tissue. HI group exhibited an enhanced MMP-2 positive staining compared to controls at 24 h, 3 and 7 days post-HI by immunohistochemistry. These results were confirmed by Western blot analysis of MMP-2 expression at 7 days post-HI. Levels of MMP-2 mRNA in the injured hippocampi increased significantly at 24 h and 7 days post-HI. In particular, the EPO treatment further significantly enhanced this increase.. EPO protected hypoxic-ischemic-induced neonatal brain damage by up-regulating the MMP-2 expression. Hence, systemic EPO may have potential utility for the treatment of HI injury in human newborns.

Topics: Animals; Animals, Newborn; Cerebral Infarction; Erythropoietin; Hippocampus; Hypoxia-Ischemia, Brain; Male; Matrix Metalloproteinase 2; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Up-Regulation

Intra-artery infusion of recombinant human erythropoietin (rhEPO) has recently been reported to confer neuroprotection against cerebral ischemia-reperfusion injury in animal models; however, the molecular mechanisms are still under investigation. The present study focused on the specific mechanism involved in blood-brain barrier (BBB) disruption.. Thirty-six male and nine female Sprague Dawley rats were subjected to middle cerebral artery (MCA) occlusion to induce focal cerebral ischemia, and administrated rhEPO at a dose of 800 U/kg through MCA infusion at the beginning of reperfusion. Neurobehavioral deficits, brain edema, and infarct volume were evaluated after 2 h of ischemia and 24 h of reperfusion. BBB permeability was assessed by quantifying the extravasation of Evans blue (EB) dye. The expression of tight junction proteins and matrix metalloproteinases (MMPs) (Claudin-5, Occludin, MMP-2, and MMP-9) in microvessels were detected by immunofluorescence and western blot. The activities of MMPs in the cerebral microvessels were determined by gelatin zymography.. Treatment with rhEPO through the MCA strongly alleviated infarct volume, brain edema, and improved neurobehavioral outcomes in male and female rats. In addition, rhEPO remarkably suppressed the EB extravasation induced by brain ischemia. Furthermore, rhEPO prevented degradation of Claudin-5 and Occludin, and reduced the expression and activity of MMP-2 and MMP-9 in isolated brain microvessels.. Treatment with rhEPO through MCA infusion prevented brain edema formation and infarction through inhibition of MMP-mediated BBB disruption in acute ischemic stroke.

Topics: Animals; Blood-Brain Barrier; Brain Edema; Brain Ischemia; Cerebral Infarction; Erythropoietin; Female; Humans; Infarction, Middle Cerebral Artery; Infusions, Intra-Arterial; Male; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Reperfusion Injury

To study biological effect of recombinant human erythropoietin (RhEPO) on the expression of oligodendrocyte in the neuron glia antigen 2(NG2), Nogo receptor-interacting protein 1(LINGO-1), myelin basic protein (MBP) and myelin associated glycoprotein (MAG), and to explore the protective mechanism of RhEPO for oligodendrocyte after cerebral infarction.. Experimental rats were randomly divided into the treatment group (RhEPO at a dose of 3 000 U/kg) or saline control group. Both groups received intraperitoneal injection of RhEPO after cerebral ischemia in 30 min, 3 h, 6 h, 12 h and 24 h, which was administered daily for 7 days. The modified neurological severity score (mNSS) and histology were analyzed, and immunohistochemistry was used to detect the protein expression of NG2, MAG, MBP and LINGO-1.. The overall mNSS of RhEPO treatment group significantly decreased compared with the saline control group on the seventh day after cerebral infarction (P<0.05). Such treatment effect was more obvious in the treatment group at 30 min and 3 h (P<0.01). Compared with the saline control group, the numbers of NG2 positive cells increased in RhEPO treatment group. In contrast, the expression of LINGO-1 protein significantly decreased (P<0.05), with a dramatic decrease observed at 30 min and 3 h (P<0.01). However, the expression of MBP protein decreased more significantly in saline control group, while the level of the MAG protein expression increased. The differences were statistically significant (P<0.05), especially at 30 min (P<0.01).. After cerebral ischemia, RhEPO promotes the proliferation of NG2 positive cells, and inhibits the expression of LINGO-1 and MAG proteins. RhEPO improves the proliferation and differentiation of oligodendrocyte precursor cells, which in turn protects neuronal function, particularly at the early phase of ischemia.

Topics: Animals; Antigens; Cell Proliferation; Cerebral Infarction; Erythropoietin; Humans; Membrane Proteins; Myelin Basic Protein; Myelin-Associated Glycoprotein; Nerve Tissue Proteins; Neurons; Oligodendroglia; Proteoglycans; Random Allocation; Rats; Recombinant Proteins; Time Factors

rhEPO has previously been shown to exert neuroprotective action in focal cerebral ischemia. However, its mechanism is not clear. We established the model of permanent focal cerebral ischemia. rhEPO was administered (5000 IU/kg i.p.) 2 h later after the successful ischemia model in rhEPO group and increased translation of Nrf2 and HO-1 and decreased the H2O2 concentration in the brain confirming activation of the Keap1-Nrf2/ARE pathway. The results show that rhEPO activate Keap1-Nrf2/ARE pathway after ischemia to protect the brain tissue.

Topics: Animals; Body Water; Brain Chemistry; Brain Ischemia; Cerebral Infarction; Erythropoietin; Heme Oxygenase-1; Hydrogen Peroxide; Intracellular Signaling Peptides and Proteins; Kelch-Like ECH-Associated Protein 1; Male; NF-E2-Related Factor 2; Rats; Rats, Sprague-Dawley; Recombinant Proteins

SMND-309 is a novel derivative of salvianolic acid B, and has shown protective effects against rat cortical neuron damage in vitro and in vivo. However the molecular mechanisms through which SMND-309 affords this protection are unclear. The present study aimed to investigate the mechanisms associated with the protective activities of SMND-309 in a cerebral ischemia and reperfusion injury rat model. In this study, we used AG490, a specific inhibitor of the signaling pathway involving the Janus Kinase 2 (JAK2)/Signal Transducers and Activators of Transcription 3 (STAT3) signaling molecules and suramin, a potent inhibitor of vascular endothelial growth factor (VEGF), to investigate the mechanisms of SMND-309. The cerebral ischemia and reperfusion injury model was induced by performing middle cerebral artery occlusion (MCAO) in the rats. SMND-309 mitigated the effects of ischemia and reperfusion injury on brain by decreasing the infract volume, improving neurological function, increasing the survival of neurons and promoting angiogenesis by increasing the levels of erythropoietin (EPO), erythropoietin receptor (EPOR), phosphorylated JAK2 (P-JAK2), phosphorylated STAT3 (P-STAT3), VEGF and VEGF receptor 2 (Flk-1) in the brain. Our results suggest that SMND-309 provides significant neuroprotective effects against cerebral ischemia and reperfusion injury. The mechanisms of this protection may be attributed to the increased VEGF expression occurring from the JAK2/STAT3 pathway, activated by the increased EPO/EPOR expression in the brain.

Topics: Animals; Axons; Benzofurans; Brain; Brain Ischemia; Caffeic Acids; Cerebral Infarction; Dendrites; Erythropoietin; Gene Expression Regulation; Infarction, Middle Cerebral Artery; Janus Kinase 2; Male; Neovascularization, Physiologic; Neuroprotective Agents; Phosphoproteins; Platelet Endothelial Cell Adhesion Molecule-1; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Recovery of Function; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor; Survival Analysis; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2; Water

Erythropoietin (EPO) has been demonstrated to possess significant neuroprotective effects in stroke. We determined if the nano-drug form of human recombinant EPO (PLGA-EPO nanoparticles [PLGA-EPO-NP]) can enhance neuroprotection at lower dosages versus human recombinant EPO (r-EPO).. Established neonatal rat model of unilateral ischemic stroke was used to compare r-EPO, PLGA-EPO-NP and phosphate-buffered saline, given by daily intraperitoneal injections, followed by infarction volume and Rotarod Performance Test assessment.. PLGA-EPO-NP significantly reduced infarction volumes 72 hours after injury compared with the same concentrations of r-EPO. Functional deficits were significantly reduced by 300 U/kg PLGA-EPO-NP versus controls, with deficit attenuation apparent at significantly lower dosages of PLGA-EPO-NP versus r-EPO.. PLGA-EPO-NP is neuroprotective and beneficial against deficits after brain ischemia, at significantly reduced dosages versus r-EPO.

Topics: Animals; Animals, Newborn; Behavior, Animal; Brain Ischemia; Cerebral Infarction; Erythropoietin; Excipients; Female; Hypoxia, Brain; Injections, Intraperitoneal; Lactic Acid; Male; Nanoparticles; Nervous System Diseases; Neuroprotective Agents; Organ Size; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Postural Balance; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Rotarod Performance Test

Previous studies have shown that erythropoietin (EPO) is neuroprotective in both in vivo and in vitro models of hypoxia ischemia. However these studies hold limited clinical translations because the underlying mechanism remains unclear and the key molecules involved in EPO-induced neuroprotection are still to be determined. This study investigated if tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and its upstream regulator signaling molecule Janus kinase-2 (JAK-2) are critical in EPO-induced neuroprotection. Hypoxia ischemia (HI) was modeled in-vitro by oxygen and glucose deprivation (OGD) and in-vivo by a modified version of Rice-Vannucci model of HI in 10-day-old rat pups. EPO treated cells were exposed to AG490, an inhibitor of JAK-2 or TIMP-1 neutralizing antibody for 2h with OGD. Cell death, phosphorylation of JAK-2 and signal transducers and activators of transcription protein-3 (STAT-3), TIMP-1 expression, and matrix metalloproteinase-9 (MMP-9) activity were measured and compared with normoxic group. Hypoxic ischemic animals were treated one hour following HI and evaluated 48 h after. Our data showed that EPO significantly increased cell survival, associated with increased TIMP-1 activity, phosphorylation of JAK-2 and STAT-3, and decreased MMP-9 activity in vivo and in vitro. EPO's protective effects were reversed by inhibition of JAK-2 or TIMP-1 in both models. We concluded that JAK-2, STAT-3 and TIMP-1 are key mediators of EPO-induced neuroprotection during hypoxia ischemia injury.

Topics: Animals; Animals, Newborn; Blotting, Western; Cell Death; Cell Differentiation; Cerebral Infarction; Culture Media; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Gelatinases; Glucose; Hypoxia-Ischemia, Brain; Immunohistochemistry; Injections, Intraventricular; Matrix Metalloproteinase 9; Neuroprotective Agents; PC12 Cells; Pregnancy; Rats; Rats, Sprague-Dawley; Tissue Inhibitor of Metalloproteinase-1

1. Asialoerythropoietin (aEPO), a derivative of cytokine erythropoietin, has been shown to have neuroprotective effects without haematological complications when administered in single or repeated doses. The present study examines our hypothesis that aEPO may provide neuroprotection against programmed apoptotic cell death when administered in a continuous low dose. 2. Focal cerebral ischaemia was introduced by occlusion of the middle cerebral artery using a surgically placed intraluminal filament in young male Sprague Dawley rats (9 weeks old). After 90 min ischaemia, reperfusion was established by filament removal. Both study and control groups had implanted osmotic minipumps through which they received either aEPO (1 microL/h; 20 microg/kg per 24 h) or normal saline (1 microL/h) for 4 days. On Day 4, infarct volume, the number of apoptotic cells and concentrations of activated caspase 3 and 9 were evaluated in the penumbra region. 3. Asialoerythropoietin was detected in the cerebrospinal fluid of the study group, whereas none was detected in the control group. Although there were no significant changes in haematocrit levels or behaviour scores (on Days 1 and 4) between the study and control groups, aEPO administration significantly reduced infarct volume in the study group compared with the control group (168 +/- 19 vs 249 +/- 28 mm(3), respectively; P < 0.05). 4. The number of terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL)-positive cells and the concentration of activated caspase 3 and 9 in the penumbra region were significantly lower in the study group compared with the control group. 5. In conclusion, our data suggest that aEPO provides a short-term, possibly histological, protection in young adult male rats when administered immediately after reperfusion.

Topics: Animals; Apoptosis; Asialoglycoproteins; Brain Ischemia; Caspase 3; Caspase 9; Cerebral Infarction; Erythropoietin; Infarction, Middle Cerebral Artery; Male; Neuroprotective Agents; Rats; Rats, Sprague-Dawley

We studied the effect of hyperbaric oxygen (HBO) preconditioning on the molecular mechanisms of neuroprotection in a rat focal cerebral ischemic model. Seventy-two male Sprague-Dawley rats were pretreated with HBO (100% O(2), 2 atmospheres absolute, 1 h once every other day for 5 sessions) or with room air. In experiment 1, HBO-preconditioned rats and matched room air controls were subjected to focal cerebral ischemia or sham surgery. Postinjury motor parameters and infarction volumes of HBO-preconditioned rats were compared with those of controls. In experiment 2, HBO-preconditioned rats and matched room air controls were killed at different time points. Brain levels of hypoxia-inducible factor-1alpha (HIF-1alpha) and its downstream target gene erythropoietin (EPO) analyzed by Western blotting and RT-PCR as well as HIF-1alpha DNA-binding and transcriptional activities were determined in the ipsilateral hemisphere. HBO induced a marked increase in the protein expressions of HIF-1alpha and EPO and the activity of HIF-1alpha, as well as the expression of EPO mRNA. HBO preconditioning dramatically improved the neurobehavioral outcome at all time points (3.0 +/- 2.1 vs. 5.6 +/- 1.5 at 4 h, 5.0 +/- 1.8 vs. 8.8 +/- 1.4 at 8 h, 6.4 +/- 1.8 vs. 9.7 +/- 1.3 at 24 h; P < 0.01, respectively) and reduced infarction volumes (20.7 +/- 4.5 vs. 12.5 +/- 3.6%, 2,3,5-Triphenyltetrazolium chloride staining) after cerebral ischemia. This observation indicates that the neuroprotection induced by HBO preconditioning may be mediated by an upregulation of HIF-1alpha and its target gene EPO.

Topics: Animals; Behavior, Animal; Blotting, Western; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; DNA; Erythropoietin; Forelimb; Hyperbaric Oxygenation; Hypoxia-Inducible Factor 1, alpha Subunit; Ischemic Preconditioning; Male; Neuroprotective Agents; Oxygen; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tetrazolium Salts; Up-Regulation

To investigate whether desferoxamine (DFO) preconditioning can induce tolerance against cerebral ischemia and its effect on the expression of hypoxia inducible factor 1alpha (HIF-1alpha) and erythropoietin (EPO) in vivo and in vitro.. Rat model of cerebral ischemia was established by middle cerebral artery occlusion with or without DFO administration. Infarct size was examined by TTC staining, and the neurological severity score was evaluated according to published method. Cortical neurons were cultured under ischemia stress which was mimicked by oxygen-glucose deprivation (OGD), and the neuron damage was assessed by MTT assay. Immunofluorescent staining was employed to detect the expressions of HIF-1alpha and EPO.. The protective effect induced by DFO (decreasing the infarction volume and ameliorating the neurological function) appeared at 2 d after administration of DFO (post-DFO), lasted until 7 d and disappeared at 14 d (P < 0.05); the most effective action was observed at 3 d post-DFO. DFO induced tolerance of cultured neurons against OGD: neuronal viability was increased 23%, 34%, 40%, 48% and 56% at 8 h, 12 h, 24 h, 36 h, and 48 h, respectively, post-DFO (P < 0.05). Immunofluorescent staining found that HIF-1alpha and EPO were upregulated in the neurons of rat brain at 3 d and 7 d post-DFO; increase of HIF-1alpha and EPO appeared in cultured cortex neurons at 36 h and 48 h post-DFO.. DFO induced tolerance against focal cerebral ischemia in rats, and exerted protective effect on OGD cultured cortical neurons. DFO significant induced the expression of HIF-1alpha and EPO both in vivo and in vitro. DFO preconditioning can protect against cerebral ischemia, which may be associated with the synthesis of HIF-1alpha and EPO.

Topics: Animals; Brain Ischemia; Cells, Cultured; Cerebral Infarction; Deferoxamine; Disease Models, Animal; Erythropoietin; Fluorescent Antibody Technique; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Ischemia, Brain; Infarction, Middle Cerebral Artery; Iron; Ischemic Preconditioning; Nerve Degeneration; Neurons; Rats; Rats, Sprague-Dawley; Siderophores; Time Factors; Treatment Outcome; Up-Regulation

Restoration of local blood supply in the post-ischemic brain plays a critical role in tissue repair and functional recovery. The present investigation explored beneficial effects of recombinant human erythropoietin (rhEPO) on vascular endothelial cell survival, angiogenesis, and restoration of local cerebral blood flow (LCBF) after permanent focal cerebral ischemia in adult mice. Saline or rhEPO (5,000 U/kg, intraperitoneal) was administered 30 mins before ischemia and once daily after ischemic stroke. Immunohistochemistry showed an enhancing effect of rhEPO on expression of EPO receptor (EPOR) of endothelial cells in the penumbra region 3 to 21 days after the ischemic insult. The treatment with rhEPO decreased ischemia-induced cell death and infarct volume 3 days after stroke. Specifically, rhEPO reduced the number of terminal deoxynucleotidyl transferase biotin-dUPT nick end labeling- and caspase-3-positive endothelial cells in the penumbra region. Colocalization of the vessel marker glucose transporter-1 (Glut-1) and cell proliferation marker 5-bromo-2'-deoxyuridine indicated enhanced angiogenic activity in rhEPO-treated mice 7 to 21 days after stroke. Western blot showed upregulation of the expression of angiogenic factors Tie-2, Angiopoietin-2, and vascular endothelial growth factor in rhEPO-treated animals. Local cerebral blood flow was measured by laser scanning imaging 3 to 21 days after stroke. At 14 days, LCBF in the penumbra was recovered to preischemia levels in rhEPO-treated mice but not in control mice. Our data suggest that rhEPO treatment upregulates the EPOR level in vascular endothelial cells, confers neurovascular protection, and enhances angiogenesis. We further show a promoting effect of rhEPO on LCBF recovery in the ischemic brain. These rhEPO-induced effects may contribute to therapeutic benefits in the treatment of ischemic stroke.

Topics: Animals; Antimetabolites; Blood Pressure; Blotting, Western; Brain Ischemia; Bromodeoxyuridine; Cerebral Infarction; Cerebrovascular Circulation; Erythropoietin; Fluorescent Antibody Technique; Heart Rate; Humans; In Situ Nick-End Labeling; Laser-Doppler Flowmetry; Male; Mice; Mice, Inbred C57BL; Neovascularization, Physiologic; Recombinant Proteins

Hypoxia is a common cause of cell death and is implicated in many disease processes including stroke and chronic degenerative disorders. In response to hypoxia, cells express a variety of genes which allow adaptation to altered metabolic demands, decreased oxygen demands, and the removal of irreversibly damaged cells. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that regulates the adaptive response to hypoxia in cells. In this study, we reported an early, time-related, gradual up-regulation of HIF-1alpha, and a moderate increase in vascular endothelial growth factor (VEGF)- and erythropoietin (Epo)-levels following transient focal ischemia. Moreover, we demonstrated, for the first time a specific localization of the pro-apoptotic regulator BNIP3 in striatal and cortical neurons after transient focal ischemia in rats. Prolonged intranuclear BNIP3 immunoreactivity was associated with delayed neuronal death. Experiments showed protein increases on Western blots of brain tissue with peaks at 48h after ischemia. Epo responds to ischemia in an early stage, whereas VEGF and BNIP3 accumulate in cells at later times after ischemia. This suggests the possibility that BH3-only proteins might be one of the major downstream effectors of HIF-1alpha in hypoxic cell death. These findings open the possibility that the hypoxia-regulated pro-apoptotic protein BNIP3 enters the nucleus and could interact with other proteins involved in DNA structure, transcription or mRNA splicing after focal brain ischemia.

Topics: Active Transport, Cell Nucleus; Animals; Apoptosis; Brain Ischemia; Cell Nucleus; Cerebral Cortex; Cerebral Infarction; Corpus Striatum; Disease Models, Animal; Erythropoietin; Gene Expression Regulation; Hypoxia-Inducible Factor 1, alpha Subunit; Infarction, Middle Cerebral Artery; Male; Membrane Proteins; Mitochondrial Proteins; Nerve Degeneration; Neurons; Proto-Oncogene Proteins; Rats; Rats, Wistar; Signal Transduction; Time Factors; Up-Regulation; Vascular Endothelial Growth Factor A

Erythropoietin (EPO) is a hormone that is neuroprotective in models of neurodegenerative diseases. This study examined whether EPO can protect against neuronal death in the CA1 region of the rat hippocampus following global cerebral ischemia. Recombinant human EPO was infused into the intracerebral ventricle either before or after the induction of ischemia produced by using the four-vessel-occlusion model in rat. Hippocampal CA1 neuron damage was ameliorated by infusion of 50 U EPO. Administration of EPO was neuroprotective if given 20 hr before or 20 min after ischemia, but not 1 hr following ischemia. Coinjection of the phosphoinositide 3 kinase inhibitor LY294002 with EPO inhibited the protective effects of EPO. Treatment with EPO induced phosphorylation of both AKT and its substrate, glycogen synthase kinase-3beta, in the CA1 region. EPO also enhanced the CA1 level of brain-derived neurotrophic factor. Finally, we determined that ERK activation played minor roles in EPO-mediated neuroprotection. These studies demonstrate that a single injection of EPO ICV up to 20 min after global ischemia is an effective neuroprotective agent and suggest that EPO is a viable candidate for treating global ischemic brain injury.

Topics: Animals; Brain Ischemia; Brain-Derived Neurotrophic Factor; Cerebral Infarction; Disease Models, Animal; Drug Administration Schedule; Enzyme Inhibitors; Erythropoietin; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Hippocampus; Injections, Intraventricular; Male; Neurons; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Recombinant Fusion Proteins; Signal Transduction; Time Factors

Perinatal asphyxia accounts for behavioral dysfunctions that often manifest as sensorimotor, learning or memory disabilities throughout development and into maturity. Erythropoietin (Epo) has been shown to exert neuroprotective effects in different models of brain injury including experimental models of perinatal asphyxia. However, the effect of Epo on functional abilities following cerebral hypoxia-ischemia (HI) in neonatal rats is not known. The aim of the present study is to investigate the effect of Epo on sensorimotor deficits and brain injury induced by hypoxia-ischemia. Seven-day-old rats underwent unilateral, permanent carotid artery ligation followed by 1 h of hypoxia. Epo was administered as a single dose immediately after the hypoxic insult (2000 U/kg). The neuroprotective effect of Epo was evaluated at postnatal day 42 by using a battery of behavioral tests and histological analysis. The results of the present study suggest that Epo treatment immediately after HI insult significantly facilitated recovery of sensorimotor function. Consistently, histopathological evaluation demonstrated that Epo significantly attenuated brain injury and preserved the integrity of cerebral cortex. These findings indicate that long-term neuroprotective effect of Epo on neonatal HI-induced brain injury might be associated with the preservation of sensorimotor functions.

Topics: Animals; Animals, Newborn; Cerebral Cortex; Cerebral Infarction; Disease Models, Animal; Erythropoietin; Female; Humans; Hypoxia-Ischemia, Brain; Ligation; Male; Movement Disorders; Neuroprotective Agents; Rats; Rats, Wistar; Recovery of Function; Sensation Disorders; Treatment Outcome

Erythropoietin (EPO) is a hematopoietic growth factor with tissue-protective properties, and can protect animals from cerebral ischemic injury. However, the central nervous effects of EPO as a glycoprotein is limited by the potential complication resulted from its erythropoietic activity and the problem of the penetration through blood-brain barrier (BBB). To avoid these limitations, in this study we administered recombinant human EPO (rhEPO) intranasally (i.n.) to evaluate its neuroprotective effect in the rats with focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO). We found that rhEPO i.n. at doses of 4.8, 12 and 24 U (administered 10 min after MCAO and 1h after reperfusion) reduced infarct volume, brain swelling and cell damage in the ischemic hemispheres, and improved behavioral dysfunction 24 h after cerebral ischemia. Intraperitoneal rhEPO (5000 U/kg) also showed the protective effect, but the heat-inactivated rhEPO did not show any effect. Thus, intranasal administration of relatively small doses of rhEPO protects rats from acute injury after focal cerebral ischemia, suggesting that intranasal rhEPO may be a more effective and safer administration route for treatments of ischemic or other brain diseases.

Topics: Administration, Intranasal; Animals; Brain Edema; Brain Ischemia; Cerebral Infarction; Disease Models, Animal; Dose-Response Relationship, Drug; Erythropoietin; Humans; Infarction, Middle Cerebral Artery; Male; Nerve Degeneration; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Recovery of Function; Treatment Outcome

Cellular response to hypoxia is mainly controlled by hypoxia-inducible factor 1 (HIF-1). The HIF-1 target gene erythropoietin (EPO) has been described as neuroprotective. Thus, we hypothesize EPO to be an essential mediator of protection in hypoxic preconditioning.. We randomized Sv129 mice into groups for different pretreatments, different hypoxia-ischemia intervals, or different durations of ischemia. For hypoxic preconditioning, the animals were exposed to a hypoxic gas mixture (8% O2 and 92% N2) for 30, 60, 180, 300, or 360 minutes. At 0, 24, 48, 72, or 144 hours later, we performed middle cerebral artery occlusion and allowed reperfusion after 30, 45, 60, or 120 minutes, or occlusion was left to be permanent. We studied EPO gene expression in brain tissue with a real-time reverse transcriptase-polymerase chain reaction and measured HIF-1 DNA-binding activity with an electrophoretic mobility shift assay. To block endogenously produced EPO, we instilled soluble EPO receptor into the cerebral ventricle.. Hypoxic preconditioning for 180 or 300 minutes induced relative tolerance to transient focal cerebral ischemia, as evidenced by a reduction of infarct volumes to 75% or 54% of the control, respectively. Hypoxic pretreatment was effective only when applied 48 or 72 hours before middle cerebral artery occlusion. Sixty minutes after hypoxia, we found a marked activation of HIF-1 DNA-binding activity and a 7-fold induction of EPO transcription. Infusion of soluble EPO receptor significantly reduced the protective effect of hypoxic pretreatment by 40%.. Endogenously produced EPO is an essential mediator of ischemic preconditioning.

Topics: Animals; Brain; Cerebral Infarction; Disease Models, Animal; DNA; DNA-Binding Proteins; Electrophoretic Mobility Shift Assay; Erythropoietin; Female; Hippocampus; Hypoxia; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Infarction, Middle Cerebral Artery; Injections, Intraventricular; Ischemic Preconditioning; Male; Mice; Mice, Inbred Strains; Nuclear Proteins; Receptors, Erythropoietin; Reperfusion; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stroke; Time Factors; Transcription Factors

There is increasing evidence that erythropoietin (Epo) has a protective function in cerebral ischemia. When used for treatment, high Epo plasma levels associated with increases in blood viscosity, however, may counteract beneficial effects of Epo in brain ischemia. The authors generated two transgenic mouse lines that overexpress human Epo preferentially, but not exclusively, in neuronal cells. In mouse line tg21, a fourfold increase of Epo protein level was found in brain only, whereas line tg6 showed a dramatic increase of cerebral and systemic transgene expression resulting in hematocrit levels of 80%. Cerebral blood flow (CBF), as determined by bolus tracking magnetic resonance imaging, was not altered in the tg6 line. The time-to-peak interval for the tracer, however, increased approximately threefold in polyglobulic tg6 mice. Immunohistochemical analysis revealed an increase in dilated vessels in tg6 mice, providing an explanation for unaltered CBF in polyglobulic animals. Permanent occlusion of the middle cerebral artery (pMCAO) led to similar perfusion deficits in wild-type, tg6, and tg21 mice. Compared with wild-type controls, infarct volumes were not significantly smaller (22%) in tg21 animals 24 hours after pMCAO, but were 49% enlarged (P < 0.05) in polyglobulic tg6 mice. In the latter animals, elevated numbers of Mac-1 immunoreactive cells in infarcted tissue suggested that leukocyte infiltration contributed to enlarged infarct volume. The current results indicate that moderately increased brain levels of Epo in tg21 transgenic mice were not sufficient to provide significant tissue protection after pMCAO. The results with tg6 mice indicate that systemic chronic treatment with Epo associated with elevated hematocrit might deteriorate outcome after stroke either because of the elevated hematocrit or other chronic effects.

Topics: Animals; Blood Flow Velocity; Blood Viscosity; Brain; Brain Ischemia; CD11 Antigens; Cerebral Infarction; Endothelium, Vascular; Erythropoietin; Gene Expression; Hematocrit; Humans; Laminin; Macrophages; Magnetic Resonance Imaging; Male; Mice; Mice, Transgenic; Middle Cerebral Artery; Monocytes; Neurons; Platelet Endothelial Cell Adhesion Molecule-1; Vascular Cell Adhesion Molecule-1

The present study describes, for the first time, a temporal and spatial cellular expression of erythropoietin (Epo) and Epo receptor (Epo-R) with the evolution of a cerebral infarct after focal permanent ischemia in mice. In addition to a basal expression of Epo in neurons and astrocytes, a postischemic Epo expression has been localized specifically to endothelial cells (1 day), microglia/macrophage-like cells (3 days), and reactive astrocytes (7 days after occlusion). Under these conditions, the Epo-R expression always precedes that of Epo for each cell type. These results support the hypothesis that there is a continuous formation of Epo, with its corresponding receptor, during the active evolution of a focal cerebral infarct and that the Epo/Epo-R system might be implicated in the processes of neuroprotection and restructuring (such as angiogenesis and gliosis) after ischemia. To support this hypothesis, a significant reduction in infarct volume (47%; P < 0.0002) was found in mice treated with recombinant Epo 24 hours before induction of cerebral ischemia. Based on the above, we propose that the Epo/Epo-R system is an endogenous mechanism that protects the brain against damages consequent to a reduction in blood flow, a mechanism that can be amplified by the intracerebroventricular application of exogenous recombinant Epo.

Topics: Animals; Astrocytes; Blotting, Western; Brain; Brain Chemistry; Brain Ischemia; Cell Death; Cells, Cultured; Cerebral Infarction; Endothelium, Vascular; Erythropoietin; Immunohistochemistry; In Situ Hybridization; Injections, Intraventricular; Mice; Neurons; Receptors, Erythropoietin

Erythropoietin (EPO) prevents the ischemia-induced delayed neuronal death in the hippocampal CA1 field in gerbils. EPO receptor (EPOR) is also expressed in the cerebral cortex but its function is not known. To examine whether EPO has a neuroprotective action in the cortex, EPO was infused into the cerebroventricles of stroke-prone spontaneously hypertensive rats with permanent occlusion of the left middle cerebral artery. Morris water maze test indicated that EPO infusion alleviated the ischemia-induced place navigation disability. The left (ischemic)-to-right (contralateral nonischemic) (L/R) ratio of cerebrocortical area in the EPO-infused ischemic group was larger than that in the vehicle-infused ischemic group. The occlusion caused secondary thalamic degeneration but infusion of EPO prevented the decrease in the L/R ratio of thalamic area and supported neuron survival in the ventroposterior thalamic nucleus. In situ hybridization indicated that EPOR mRNA was upregulated in the periphery (ischemic penumbra) of a cerebrocortical infarct after occlusion of the middle cerebral artery, suggesting that an increased number of EPOR in neurons facilitates the EPO signal transmission, thereby preventing the damaged area from enlarging.

Topics: Animals; Arterial Occlusive Diseases; Cell Count; Cerebral Arteries; Cerebral Infarction; Cerebrovascular Disorders; Erythropoietin; Infusion Pumps, Implantable; Maze Learning; Nerve Degeneration; Neurons; Rats; Receptors, Erythropoietin; RNA, Messenger; Spatial Behavior; Thalamus