losartan-potassium and Brain-Edema

Traumatic brain injury (TBI) remains one of the leading causes of mortality and morbidity worldwide in individuals under the age of 45 years, and, despite extensive efforts to develop neuroprotective therapies, there has been no successful outcome in any trial of neuroprotection to date. In addition to recognizing that many TBI clinical trials have not been optimally designed to detect potential efficacy, the failures can be attributed largely to the fact that most of the therapies investigated have been targeted toward an individual injury factor. The contemporary view of TBI is that of a very heterogenous type of injury, one that varies widely in etiology, clinical presentation, severity, and pathophysiology. The mechanisms involved in neuronal cell death after TBI involve an interaction of acute and delayed anatomic, molecular, biochemical, and physiological events that are both complex and multifaceted. Accordingly, neuropharmacotherapies need to be targeted at the multiple injury factors that contribute to the secondary injury cascade, and, in so doing, maximize the likelihood of a successful outcome. This review focuses on a number of such multifunctional compounds that have shown considerable success in experimental studies and that show maximum promise for success in clinical trials.

Topics: Animals; Brain Edema; Brain Injuries; Cyclosporine; Dronabinol; Erythropoietin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Kinins; Magnesium; Minocycline; Mitochondria; Neuroprotective Agents; Oxidative Stress; Progesterone; Psychotropic Drugs; Thyrotropin-Releasing Hormone; Toll-Like Receptors

Topics: Adrenal Cortex Hormones; Angioedema; Blood Component Transfusion; Brain Edema; Cyclosporins; Endothelium, Vascular; Erythropoietin; Humans; Hypertensive Encephalopathy; Immunosuppressive Agents; Magnetic Resonance Imaging; Seizures; Syndrome

The vascular events that happen during ischemic stroke worsen outcomes in patients by causing edema, hemorrhagic transformation, and general neurologic tissue compromise. In the past 2 decades, clinical trials in patients after ischemic stroke focused on neuroprotection, but these strategies have failed in providing actual benefit. Vascular protection represents a new field to be explored in acute ischemic stroke in order to develop new approaches to therapeutic intervention.. We identified tactics likely to provide vascular protection in patients with ischemic stroke. These tactics are based on knowledge of the molecular processes involved.. The pathologic processes due to vascular injury after an occlusion of a cerebral artery can be separated into acute (those occurring within hrs), subacute (hrs to days), and chronic (days to mo). Targets for intervention can be identified for all three stages. In the acute phase, superoxide is the predominant mediator, followed by inflammatory mediators and proteases in the subacute phase. In the chronic phase, proapoptotic gene products have been implicated. Many already-marketed therapeutic agents (statins, angiotensin modulators, erythropoietin, minocycline, and thiazolidinediones), with proven safety in patients, have been shown to have activity against some of the key targets of vascular protection.. Currently available pharmacologic agents are poised for clinical trials of vascular protection after acute ischemic stroke.

Topics: Acute Disease; Angiotensin-Converting Enzyme Inhibitors; Brain; Brain Edema; Brain Ischemia; Cerebral Hemorrhage; Chronic Disease; Erythropoietin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Minocycline; Stroke; Thiazolidinediones; Thrombolytic Therapy

Traumatic brain injury (TBI) is a serious health problem with few available treatment options. Rh-erythropoietin (rh-EPO) is a potential therapeutic drug for TBI, but it cannot cross the blood-brain barrier (BBB) directly. In this regard, a novel strategy to deliver rh-EPO for enhanced TBI treatment is via the development of Tween 80 modified albumin nanoparticles using electrostatic spray technology.. The rh-EPO loaded Tween 80 modified albumin nanoparticles (rh-EPO-Tw-ABNPs) were prepared by electrostatic spray technology, while the process parameters were optimized via a single factor design. Investigation of physicochemical properties, bioactivity and stability of rh-EPO-Tw-ABNPs was carried out. The in vitro release and biocompatibility with nerve cells were also analyzed. The in vivo brain targeting efficiency, brain edema relieving effect and the expression of aquaporin 4 (AQP4) and glial fibrillary acidic protein (GFAP) in the brain were evaluated in TBI model rats.. The particle size of optimal rh-EPO-Tw-ABNPs was about 438 ± 45 nm, with a zeta potential of -25.42 ± 0.8 mv. The average drug loading ratio of rh-EPO-Tw-ABNPs was 21.3± 3.7 IU/mg with a relative bioactivity of 91.6 ± 4.1%. The in vitro release of rh-EPO from the nanoparticles was rather slow, while neither the blank Tw-ABNPs nor rh-EPO-Tw-ABNPs exhibited toxicity on the microglia cells. Furthermore, in vivo experiments indicated that the rh-EPO-Tw-ABNPs could enhance the distribution of EPO in the brain and relieve brain edema more effectively. Moreover, compared with an rh-EPO injection, the rh-EPO-Tw-ABNPs could increase the AQP4 level but reduced GFAP expression in the brain with more efficiency.. The rh-EPO-Tw-ABNPs could enhance the transport of rh-EPO into the brain with superior therapeutic effect for TBI.

Topics: Albumins; Animals; Aquaporin 4; Brain; Brain Edema; Brain Injuries, Traumatic; Drug Liberation; Erythropoietin; Glial Fibrillary Acidic Protein; Humans; Male; Nanoparticles; Neurons; Particle Size; Rats, Sprague-Dawley; Recombinant Proteins; Rheology; Static Electricity

Effect of recombinant human erythropoietin (rhEPO) on spontaneous motor activity was tested in young rats after intraperitoneal (i.p.) administration of rhEPO, followed by induction of cellular brain edema (CE). Induced changes in the spontaneous horizontal locomotor activity was studied by open field test (OFT).. CE was induced by water intoxication (WI) using standard method of fractional hyperhydration accompanied with desmopressin administration. Using the accepted method of OFT average time spent in locomotion (s) was determined. 48 young rats at the age of 25, and 35 days were divided into three groups - controls, rats after WI (OFT followed after 44 hours), and rats administered with rhEPO prior to application WI (OFT after 48 hours).. In 35-day-old rats rhEPO administration increased the spontaneous locomotor activity, previously decreased by cellular edema. In 25-day-old rats, rhEPO administration prior to the induced CE, decreased spontaneous locomotor activity.. Presented results demonstrate the neuroprotective capacity of rhEPO, manifested by elimination of the suppressive influence of CE on the locomotion in 35-day-old rats. In 25-day-old rats the neuroprotective effect was not present. These results confirmed that the 10 day interval in the development may represent a different stage of brain maturation in the relation to the neuroprotective effect of rhEPO.

Topics: Age Factors; Animals; Behavior, Animal; Brain Edema; Erythropoietin; Locomotion; Male; Motor Activity; Neuroprotective Agents; Rats; Rats, Wistar; Recombinant Proteins; Water Intoxication

Inflammatory modulation mediated by microglial M1/M2 polarization is one of the main pathophysiological processes involved in early brain injury (EBI) after subarachnoid haemorrhage (SAH). Previous studies have shown that recombinant human erythropoietin (rhEPO) alleviates EBI following experimental SAH. However, the mechanisms of this beneficial effect are still poorly understood. Recent research has suggested that EPO shows anti-inflammatory properties. Therefore, we tried to analyse whether rhEPO administration influenced microglial M1/M2 polarization in early brain injury after SAH and to identify the underlying molecular mechanism of any such effect. We found that treatment with rhEPO markedly ameliorated SAH-induced EBI, as shown by reductions in brain cell apoptosis, neuronal necrosis, albumin exudation and brain edema. Moreover, the expression levels of p-JAK2 and p-STAT3 were significantly increased in the cortex after SAH induction and were further increased by EPO treatment; in addition, the p-JAK2 inhibitor AZD1480 impaired the protective effect of EPO against SAH-induced EBI in vivo. Furthermore, EPO promoted the polarization of microglia towards the protective M2 phenotype and alleviated inflammation. In cultured microglia under oxyhemoglobin (OxyHb) treatment, EPO up-regulated the expression of the EPO receptor (EPOR), which did not occur in response to OxyHb treatment alone, and EPO magnified OxyHb-induced increases in p-JAK2 and p-STAT3 and modulated OxyHb-challenged microglial polarization towards M2. Interestingly, the effect of EPO on microglia polarization was cancelled by EPOR knockdown or by p-JAK2 or p-STAT3 inhibition, suggesting a core role of the EPOR/JAK2/STAT3 pathway in modulating microglial function and phenotype. In conclusion, the therapeutic effect of rhEPO on the early brain injury after SAH may relate to its modulation of inflammatory response and microglia M1/M2 polarization, which may be mediated in part by the EPOR/JAK2/STAT3 signalling pathway. These results improved the understanding of the anti-inflammatory effect of EPO on microglia polarization, which might optimize the therapeutic modalities of EPO treatment with SAH.

Topics: Animals; Anti-Inflammatory Agents; Brain Edema; Cell Differentiation; Cell Line; Cerebral Cortex; Disease Models, Animal; Erythropoietin; Gene Expression Regulation; Humans; Injections, Intraventricular; Janus Kinase 2; Mice; Mice, Inbred C57BL; Microglia; Neurons; Oxyhemoglobins; Pyrazoles; Pyrimidines; Receptors, Erythropoietin; Recombinant Proteins; Signal Transduction; STAT3 Transcription Factor; Stereotaxic Techniques; Subarachnoid Hemorrhage

Hypoxic-ischemic (HI) injury to the developing brain remains a major cause of morbidity. To date, few therapeutic strategies could provide complete neuroprotection. Erythropoietin (EPO) has been shown to be beneficial in several models of neonatal HI. This study examines the effect of treatment with erythropoietin on postnatal day 2 (P2) rats introduced with HI injury.. Rats at P2 were randomized into four groups: sham, bilateral carotid artery occlusion (BCAO), BCAO + early EPO, and BCAO + late EPO groups. Pups in each group were injected with either saline or EPO (5000U/kg) intraperitoneally once at immediately (early) or 48h (late) after HI induction. Body weight was assessed at P2 before and day 7 after HI. Mortality Rate was assessed at 24h, 48h and 72h after HI and brain water content was assessed at 72h. Brain weight and expression of myelin basic protein (MBP) were assessed at day 7 and day 14. At day 31 to 35 following HI insult, neurological behavior function was assessed via Morris water maze (MWM) test.. HI cause significant higher mortality in male than in female (P=0.0445). Among the surviving animal, HI affect significantly the body growth, brain growth, MBP expression, and neurological behavior. EPO treatments at both early and late time points significantly benefit the rats in injury recovery, in which they promoted weight gains, reduced brain edema, as well as improved spatial learning ability and memory.. We demonstrated a single dose of EPO at 5000U/kg immediately or 48h after HI injury had significant benefit for the P2 rats in injury recovery, and there was no adverse effect associated with either EPO treatment.

Topics: Age Factors; Analysis of Variance; Animals; Animals, Newborn; Body Weight; Brain Edema; Developmental Disabilities; Disease Models, Animal; Erythropoietin; Hypoxia-Ischemia, Brain; Maze Learning; Myelin Basic Protein; Neuroprotective Agents; Rats; Rats, Sprague-Dawley

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

The aim of this study was to investigate the protective effects of erythropoietin, dextran/saline and erythropoietin in combination with dextran/saline on brain edema and lipid peroxidation following traumatic brain injury in rats.. In the study, 40 male 3-month-old albino Wistar rats, weighing 250-340 g, were divided into four groups, each consisting of ten rats. Traumatic brain injury was induced in all rats by the weight-drop method, and erythropoietin (5,000 U/kg) and/or dextran and saline (8 ml/kg) solutions were injected intraperitoneally ten minutes after trauma. Control animals received an equal volume of serum physiologic. All rats were sacrificed 24 hours later. Glutathione peroxidase activity and malondialdehyde levels were measured in the left hemisphere, and edema was quantitated by the wet-dry method.. Brain edema and the levels of malondialdehyde, the last product of lipid peroxidation in tissues, were decreased variably, and the activity of glutathione peroxidase, an antioxidant enzyme, was increased in others compared with the control group.. In this study, it was concluded that the brain edema that developed in rats on which head trauma was induced and the secondary brain damage caused by oxidative stress could be deceased using a combination of erythropoietin, dextran, and saline.

Topics: Animals; Brain Edema; Brain Injuries; Dextrans; Disease Models, Animal; Drug Combinations; Erythropoietin; Glutathione Peroxidase; Injections, Intraperitoneal; Lipid Peroxidation; Male; Malondialdehyde; Neuroprotective Agents; Rats; Rats, Wistar; Sodium Chloride

Traumatic brain injury (TBI) is one of the leading causes of disability and death which begins with the formation of edema as the persistent primary causative factor in TBI. Although medical management of cerebral edema by hypothermia, ventriculostomy, mannitol or hypertonic saline have been effective in treating edema, many of these therapies end up with some neurologic deficits, necessitating novel treatment options for treating post-TBI edema. This study investigated edema reducing effects of recombinant human Erythropoietin (rhEPO) in reducing acute brain edema in the CCI mouse model of TBI.. Anti-edema effects of rhEpo in reducing acute brain edema after injury in the CCI mouse model of TBI were assessed by T2 weighted magnetic resonance imaging (T2wMRI) as the accurate detector of brain edema in correlation with Western blot analysis of cerebral aquaporin 4 (AQP4) index as the critical marker of edema.. Results show that rhEpo treatment significantly reduced brain edema with concomitant reduction in AQP4 immunoexpression in the CCI mouse model of TBI.. Current results emphasize clinical utility of rhEpo in treating post-TBI edema.

Topics: Animals; Aquaporin 4; Blotting, Western; Brain; Brain Edema; Brain Injuries; Disease Models, Animal; Drug Evaluation, Preclinical; Erythropoietin; Humans; Imaging, Three-Dimensional; Injections, Intraperitoneal; Magnetic Resonance Imaging; Male; Mice, Inbred C57BL; Neuroprotective Agents; Recombinant Proteins; Treatment Outcome

To investigate the effects of recombinant human erythropoietin on brain oxygenation in a model of diffuse traumatic brain injury.. Adult male Wistar rats.. Neurosciences and physiology laboratories.. Thirty minutes after diffuse traumatic brain injury (impact-acceleration model), rats were intravenously administered with either a saline solution or a recombinant human erythropoietin (5000 IU/kg). A third group received no traumatic brain injury insult (sham-operated).. Three series of experiments were conducted 2 hours after traumatic brain injury to investigate: 1) the effect of recombinant human erythropoietin on brain edema using diffusion-weighted magnetic resonance imaging and measurements of apparent diffusion coefficient (n = 11 rats per group); local brain oxygen saturation, mean transit time, and blood volume fraction were subsequently measured using a multiparametric magnetic resonance-based approach to estimate brain oxygenation and brain perfusion in the neocortex and caudoputamen; 2) the effect of recombinant human erythropoietin on brain tissue PO₂ in similar experiments (n = 5 rats per group); and 3) the cortical ultrastructural changes after treatment (n = 1 rat per group). Compared with the sham-operated group, traumatic brain injury saline rats showed a significant decrease in local brain oxygen saturation and in brain tissue PO₂ alongside brain edema formation and microvascular lumen collapse at H2. Treatment with recombinant human erythropoietin reversed all of these traumatic brain injury-induced changes. Brain perfusion (mean transit time and blood volume fraction) was comparable between the three groups of animals.. Our findings indicate that brain hypoxia can be related to microcirculatory derangements and cell edema without evidence of brain ischemia. These changes were reversed with post-traumatic administration of recombinant human erythropoietin, thus offering new perspectives in the use of this drug in brain injury.

Topics: Animals; Brain; Brain Edema; Brain Injuries; Brain Ischemia; Cerebrovascular Circulation; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Erythropoietin; Humans; Infusions, Intravenous; Male; Microcirculation; Oxygen Consumption; Random Allocation; Rats; Rats, Wistar; Reference Values; Risk Factors

Carbamylated erythropoietin (C-EPO), one of the erythropoietin derivatives, retains strong anti-edema and neuroprotective properties while lacking the hematopoietic complications of erythropoietin. This study investigated the intracellular and molecular mechanisms underlying the anti-edema property of C-EPO. An in vitro model of astrocyte swelling was created by 5h of oxygen-glucose deprivation and subsequent reperfusion (OGD/Rep). Astrocyte cultures were then treated with C-EPO or left as control cells. Here we show that increases in astrocyte volume, morphological cell swelling, and changes in ultrastructure after OGD/Rep were significantly mitigated by treatment with C-EPO (10 ng/ml). The decreases in AQP-4 phosphorylation after OGD/Rep were remarkably recovered by C-EPO treatment. The OGD/Rep-induced upregulations of AQP-4 mRNA and protein were also prevented by C-EPO treatment. Additional treatment with phorbol myristate acetate, an activator of protein kinase C (PKC), enhanced C-EPO-mediated neuroprotective effects, while that of H-7, an inhibitor of PKC, blocked these protections. Our findings establish that C-EPO effectively mitigates astrocyte swelling induced by ischemia and reperfusion-like injury. The modulation of AQP-4 phosphorylation and expression via the PKC pathway is participated in the neuroprotective effects of C-EPO.

Topics: Animals; Animals, Newborn; Aquaporin 4; Astrocytes; Brain Edema; Erythropoietin; Glucose; Microscopy, Electron; Neuroprotective Agents; Oxygen; Phosphorylation; Primary Cell Culture; Protein Kinase C; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Erythropoietin (EPO) has demonstrated neuroprotective effects against traumatic brain injury (TBI), but the underlying mechanisms remain unclear. The signaling pathway of an antioxidant transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), has been shown in our previous studies to play an important role in protecting mice from TBI-induced secondary brain injury. The present study explored the effect of recombinant human erythropoietin (rhEPO) on cerebral activation of the Nrf2 signaling pathway and secondary brain injury in mice after TBI. Adult male ICR mice were randomly divided into three groups: (1) Sham group; (2) TBI group; and (3) TBI+rhEPO group (n = 12 per group). Closed head injury was performed using Hall's weight-dropping method. rhEPO was administered at a dose of 5,000 IU/kg at 30 min after TBI. Brain samples were extracted at 24 hr after the trauma. The treatment with rhEPO markedly up-regulated the mRNA expression and activities of Nrf2 and its downstream cytoprotective enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1). Administration of rhEPO also significantly ameliorated the secondary brain injury, as shown by decreased severity of neurological deficit, brain edema, and cortical apoptosis. In summary, post-TBI rhEPO administration induces Nrf2-mediated cytoprotective responses in the injured brain, and this may be a mechanism whereby rhEPO improves the outcome following TBI.

Topics: Animals; Apoptosis; Brain Edema; Brain Injuries; Cerebral Cortex; DNA; Erythropoietin; Hand Strength; Humans; In Situ Nick-End Labeling; Male; Mice; NAD(P)H Dehydrogenase (Quinone); Nervous System Diseases; NF-E2-Related Factor 2; Protein Binding; Recombinant Proteins; RNA, Messenger; Signal Transduction

To investigate the effects of carbamylated erythropoietin, a modified erythropoietin lacking erythropoietic activity, on brain edema and functional recovery in a model of diffuse traumatic brain injury.. Adult male Wistar rats.. Neurosciences and physiology laboratories.. Thirty minutes after diffuse traumatic brain injury (impact-acceleration model), rats were intravenously administered with either a saline solution (traumatic brain injury-saline) or carbamylated erythropoietin (50 μg/kg; traumatic brain injury-carbamylated erythropoietin). A third group received no traumatic brain injury insult (sham-operated).. Three series of experiments were conducted to investigate: 1) the effect of carbamylated erythropoietin on brain edema before and 1 hr after traumatic brain injury using diffusion-weighted magnetic resonance imaging and measurements of apparent diffusion coefficient (n = 10 rats per group), and the phosphorylation level of brain extracellular-regulated kinase-1/-2 was also determined to indicate the presence of an activated cell signaling pathway; 2) the time course of brain edema using magnetic resonance imaging between 4 and 6 hrs postinjury and the gravimetric technique at 6 hrs (n = 10 rats per group); and 3) motor and cognitive function over 10 days post traumatic brain injury, testing acute somatomotor reflexes, adhesive paper removal, and two-way active avoidance (n = 8 rats per group). Compared to traumatic brain injury-saline rats, rats receiving traumatic brain injury-carbamylated erythropoietin showed a significant reduction in brain edema formation at 1 hr that was sustained until 6 hrs when results were comparable with sham-operated rats. This antiedematous effect of carbamylated erythropoietin was possibly mediated through an early inhibition of extracellular-regulated kinase-1/-2 phosphorylation. Compared to traumatic brain injury-saline rats, traumatic brain injury-carbamylated erythropoietin rats showed improved functional recovery of the acute somatomotor reflexes post traumatic brain injury, took less time to remove adhesive from the forelimbs, and showed higher percentages of correct avoidance responses.. Our findings indicate that early posttraumatic administration of carbamylated erythropoietin reduces brain edema development until at least 6 hrs postinjury and improves neurologic recovery. Carbamylated erythropoietin can thus be considered as a potential agent in the treatment of traumatic brain injury-induced diffuse edema.

Topics: Animals; Brain; Brain Edema; Brain Injuries; Cognition Disorders; Erythropoietin; Magnetic Resonance Imaging; Male; Psychomotor Disorders; Rats; Rats, Wistar; Reflex; Time Factors

Topics: Animals; Brain Edema; Brain Injuries; Erythropoietin; Male

We found that recombinant human erythropoietin (rhEPO) reduced significantly the development of brain edema in a rat model of diffuse traumatic brain injury (TBI) (impact-acceleration model). In this study, we investigated the molecular and intracellular changes potentially involved in these immediate effects. Brain tissue nitric oxide (NO) synthesis, phosphorylation level of two protein kinases (extracellular-regulated kinase (ERK)-1/-2 and Akt), and brain water content were measured 1 (H1) and 2 h (H2) after insult. Posttraumatic administration of rhEPO (5,000 IU/kg body weight, intravenously, 30 mins after injury) reduced TBI-induced upregulation of ERK phosphorylation, although it increased Akt phosphorylation at H1. These early molecular changes were associated with a reduction in brain NO synthesis at H1 and with an attenuation of brain edema at H2. Intraventricular administration of the ERK-1/-2 inhibitor, U0126, or the Akt inhibitor, LY294002, before injury showed that ERK was required for brain edema formation, and that rhEPO-induced reduction of edema could involve the ERK pathway. These results were obtained in the absence of any evidence of blood-brain barrier damage on contrast-enhanced magnetic resonance images. The findings of our study indicate that the anti edematous effect of rhEPO could be mediated through an early inhibition of ERK phosphorylation after diffuse TBI.

Topics: Animals; Blood-Brain Barrier; Blotting, Western; Brain Edema; Brain Injuries; Disease Models, Animal; Erythropoietin; Humans; Male; Phosphorylation; Protein Kinases; Rats; Rats, Wistar; Recombinant Proteins

Topics: Animals; Brain Edema; Brain Ischemia; Erythropoietin; Female; Hippocampus; Male; Nitric Oxide; Protective Agents; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Superoxide Dismutase

Disturbed brain water homeostasis with swelling of astroglial cells is a common complication in stroke, trauma, and meningitis and is considered to be a major cause of permanent brain damage. Astroglial cells possess the water channel aquaporin 4 (AQP4). Recent studies from our laboratory have shown that glutamate, acting on group I metabotropic glutamate receptors (mGluRs), increases the permeability of astrocyte AQP4, which, in situations of hypoxia-ischemia, will increase astrocyte water uptake. Here we report that erythropoietin (EPO), which in recent years has emerged as a potent neuro-protective agent, antagonizes the effect of a group I mGluR agonist on astrocyte water permeability. Activation of group I mGluRs triggers fast and highly regular intracellular calcium oscillations and we show that EPO interferes with this signaling event by altering the frequency of the oscillations. These effects of EPO are immediate, in contrast to the neuroprotective effects of EPO that are known to depend upon gene activation. Our findings indicate that EPO may directly reduce the risk of astrocyte swelling in stroke and other brain insults. In support of this conclusion we found that EPO reduced the neurological symptoms in a mouse model of primary brain edema known to depend upon AQP4 water transport.

Topics: Animals; Aquaporin 4; Astrocytes; Brain Edema; Calcium Signaling; Cells, Cultured; Erythropoietin; Female; Hippocampus; In Vitro Techniques; Mice; Mice, Inbred C3H; Permeability; Rats; Receptors, Glutamate; Water

Intracerebral hemorrhage (ICH) is a devastating clinical syndrome for which no truly efficacious therapy has yet been identified. In preclinical studies, erythropoietin (EPO) and its long-lasting analog, darbepoetin alfa, have been demonstrated to be neuroprotective in several models of neuronal insult. The objectives of this study were to analyze whether the systemic administration of recombinant human EPO (rHuEPO) and its long-lasting derivative darbepoetin alfa expedited functional recovery and brain damage in a rat model of ICH.. Experimental ICH was induced in rats by injecting autologous blood into the right striatum under stereotactic guidance. Subsequently, animals underwent placebo treatment, daily injections of rHuEPO, or weekly injections of darbepoetin alfa. Animals were killed 14 days after injury.. Both rHuEPO and darbepoetin alfa were effective in reducing neurological impairment after injury, as assessed by the neurological tasks performed. rHuEPO- and darbepoetin alfa-treated animals exhibited a restricted brain injury with nearly normal parenchymal architecture. In contrast, the saline-treated group exhibited extensive cerebral cytoarchitectural disruption and edema. The number of surviving NeuN-positive neurons was significantly higher in the rats treated with rHuEPO and darbepoetin alfa compared with those that received saline (P < 0.05).. These results demonstrate that weekly administered darbepoetin alfa confers behavioral and histological neuroprotection after ICH in rats similar to that of daily EPO administration. Administration of EPO and its long-lasting recombinant forms affords significant neuroprotection in an ICH model and may hold promise for future clinical applications.

Topics: Animals; Basal Ganglia Hemorrhage; Blood Transfusion, Autologous; Brain; Brain Edema; Brain Infarction; Cerebral Hemorrhage; Corpus Striatum; Darbepoetin alfa; Disease Models, Animal; Drug Administration Schedule; Erythropoietin; Hematinics; Humans; Male; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Treatment Outcome

To investigate the protective effects of ginkgolide B and hypoxic preconditioning against acute hypoxia injury in mice.. Ordinary pressure acute hypoxia model in mice was adopted to observe the ethology, the duration of the death and the degree of brain edema. Meanwhile the expression of RTP801 mRNA and erythropoietin (EPO) were measured by RT-PCR and Western blot, respectively.. Ginkgolide B and hypoxic preconditioning could both prolong the survival time of hypoxia under ordinary pressure,and significantly decreased the degree of brain edema. Besides ginkgolide B and hypoxic preconditioning could both up-regulate the expression of RTP801mRNA and EPO.. Ginkgolide B has the similar effect to hypoxic preconditioning against acute hypoxia. Both of these protective effects may be associated with the up-regulation of the expression of RTP801 mRNA and EPO.

Topics: Animals; Brain; Brain Edema; Erythropoietin; Female; Ginkgolides; Hypoxia; Ischemic Preconditioning; Lactones; Male; Mice; Mice, Inbred ICR; Reperfusion Injury; Repressor Proteins; RNA, Messenger; Transcription Factors; Up-Regulation

The protective mechanism of recombinant human erythropoietin (rhEPO) on blood-brain barrier (BBB) after brain injury is associated with the attenuation of neuro-inflammation. We hypothesize that rhEPO treatment after intracerebral hemorrhage (ICH) modulates matrix metalloproteinase (MMP) activity, maintains BBB integrity, and reduces BBB breakdown-associated inflammation. Adult male 129S2/sv mice were subjected to autologous whole blood-induced ICH. rhEPO or saline was administered intraperitoneally immediately after surgery and for 3 more days until day of sacrifice. BBB permeability was measured by Evans blue leakage, and edema was assessed by brain water content. Immunofluorescence and Western blotting were performed to detect expression of tight junction marker occludin, type IV collagen, MMPs, tissue inhibitor of metalloproteinase (TIMP), and glial fibrillary acidic protein, rhEPO prevented Evans blue leakage, reduced brain edema, and preserved expression of occludin and collagen IV. rhEPO treatment decreased MMP-2 expression, increased TIMP-2 expression, and reduced the number of reactive astrocytes in the brain compared to saline control. We conclude that rhEPO reduces MMP activity, BBB disruption, and the glial cell inflammatory reaction 3 days after ICH. Our study provides additional evidence for the mechanism of rhEPO's neurovascular protective effects and a potential clinical application in the treatment of ICH.

Topics: Animals; Blood-Brain Barrier; Brain Edema; Cerebral Hemorrhage; Collagen Type IV; Disease Models, Animal; Erythropoietin; Evans Blue; Glial Fibrillary Acidic Protein; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinases; Membrane Proteins; Mice; Occludin; Permeability; Recombinant Proteins; Time Factors; Tissue Inhibitor of Metalloproteinases

Both heat acclimation (HA) and post-injury treatment with recombinant human erythropoietin (Epo, rhEpo, exogenous Epo) are neuroprotective against traumatic brain injury (TBI). Our previous data demonstrated that HA-induced neuroprotection includes improved functional recovery and reduced cerebral edema formation. Additionally, in earlier Western-blot analyses, we found that HA mice display increased expression of the specific erythropoietin receptor (EpoR) and of hypoxia-inducible factor-1 alpha (HIF-1 alpha), the inducible subunit of the transcription factor, which regulates Epo gene expression, but not of Epo itself. In light of this, the aim of the current study was threefold: (1) to assess Epo expression in the trauma area and hippocampus following HA, rhEpo administration, or combined HA-rhEpo treatment, using immunohistochemical methods that offer enhanced anatomical resolution; (2) to examine the effects of endogenous and exogenous Epo on edema formation in normothermic (NT) mice; and (3) to evaluate the effects of exogenous Epo administration on neuroprotective outcome measures in HA animals. HA induced enhanced expression of endogenous Epo in the trauma area and the hippocampus. Treatment with anti-Epo antibody given to NT mice increased edema formation, whereas rhEpo induced no beneficial effect. Cognitive performance testing and immunohistochemical findings reinforced HA and rhEpo as separate protective interventions but showed no advantage to combining the two strategies. We therefore suggest that HA-induced neuroprotection is shaped by pre-existing mediators but cannot be modified by post-injury treatment aimed at increasing the levels of neuroprotective agents.

Topics: Acclimatization; Animals; Brain Edema; Brain Injuries; Cognition; Erythropoietin; Fluoresceins; Fluorescent Dyes; Hippocampus; Hot Temperature; Humans; Immunohistochemistry; Immunotherapy; Male; Mice; Nerve Degeneration; Neuroprotective Agents; Organic Chemicals; Recognition, Psychology; Recombinant Proteins

The aims of this study were to evaluate the efficiency of EPO in the treatment of cold injury-induced brain edema, apoptosis, and inflammation and to compare its effectiveness with DSP.. One hundred fifteen adult male Sprague-Dawley rats weighing between 280 and 300 g were used for the study. Rats were divided into 5 groups. Controls received craniotomy only. The injury group underwent cold injury and had no medication. In the EPO group, a single dose of 1000 IU/kg body weight of EPO was administered. The DSP group received 0.2 mg/kg body weight of DSP. The vehicle group received a vehicle solution containing human serum albumin, which is the solvent for EPO. Brain edema was formed by cold injury using metal sterile rods with a diameter of 4 mm that were previously cooled at -80 degrees C. Twenty-four hours after the injury, animals were decapitated and brain tissues were investigated for brain edema, tissue MPO and caspase-3 levels, and ultrastructure.. A significant increase in brain water content was revealed in injury group of rats at 24 hours after cold injury. Injury significantly increased tissue MPO and caspase-3 levels and resulted in ultrastructural damage. Both EPO and DSP markedly decreased tissue MPO and caspase-3 levels and preserved ultrastructure of the injured brain cortex.. Erythropoietin and DSP were found to be neuroprotective in cold injury-induced brain edema model in rats via anti-apoptotic and anti-inflammatory actions.

Topics: Animals; Blood-Brain Barrier; Brain Edema; Brain Injuries; Caspase 3; Cold Temperature; Dexamethasone; Disease Models, Animal; Erythropoietin; Glucocorticoids; Male; Peroxidase; Rats; Rats, Sprague-Dawley

Hyperbaric oxygen preconditioning (HBO-PC) has been shown to be effective in preventing hypoxic injuries in many animal models. The aim of the present study was to examine the hypoxic tolerance induced by HBO-PC and to explore the role of hypoxia-inducible factor-1alpha (HIF-1alpha) in a global hypoxia model. Male mice received HBO-PC before hypoxia exposure and swimming. HBO-PC significantly prolonged the survival time and the tolerance time of swimming under normobaric hypoxia. HBO-PC increased the protein content of HIF-1alpha and erythropoietin (EPO) in the cerebral cortex and hippocampus and prevented the changes of blood brain barrier (BBB) permeability and brain edema caused by hypoxia exposure. The results suggested that HBO-PC induced hypoxic tolerance in mice via up-regulation of HIF-1alpha and its downstream genes.

Topics: Analysis of Variance; Animals; Behavior, Animal; Brain Edema; Cerebral Cortex; Disease Models, Animal; Erythropoietin; Hippocampus; Hyperbaric Oxygenation; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Ischemic Preconditioning; Male; Mice; Mice, Inbred Strains; Survival Analysis; Time Factors; Up-Regulation

Erythropoietin (Epo) is gaining interest in various neurological insults as a possible neuroprotective agent. We determined the effects of recombinant human Epo (rhEpo, 5000 IU per kg bw) on brain edema induced in rats by traumatic brain injury (TBI; impact-acceleration model; rhEpo administration 30 mins after injury). Magnetic resonance imaging (MRI) and a gravimetric technique were applied. In the MRI experiments, the apparent diffusion coefficient (ADC) and the tissue T(1) relaxation time were measured hourly in the neocortex and caudoputamen, during a 6 h time span after TBI. In the gravimetric experiments, brain water content (BWC) was determined in these two regions, 6 h after TBI. Apparent diffusion coefficient measurements showed that rhEpo decreased brain edema early and durably. Gravimetric measurements showed that rhEpo decreased BWC at H(6) in the neocortex as well as in the caudoputamen. No significant differences in ADC, in T(1), or in BWC were found between rhEpo treated-TBI rats and sham-operated rats. Our findings show that post-traumatic administration of rhEpo can significantly reduce the development of brain edema in a model of diffuse TBI. Further studies should be conducted to identify the biochemical mechanisms involved in these immediate effects and to assess the use of rhEpo as a possible therapy for post-traumatic brain edema.

Topics: Animals; Brain Edema; Brain Injuries; Erythropoietin; Humans; Magnetic Resonance Imaging; Neuroprotective Agents; Rats; Rats, Wistar; Recombinant Proteins

Recombinant human erythropoietin (rhEPO), a neurovascular protective agent, therapeutically supports angiogenesis after stroke by enhancing endogenous up-regulation of vascular endothelial growth factor (VEGF). Increased VEGF expression has been characterized to negatively impact the integrity of the blood brain barrier (BBB), causing brain edema and secondary injury. The present study investigated the rhEPO-induced BBB protection after stroke and how it might be achieved by affecting VEGF pathway. rhEPO treatment (5,000 U/kg, i.p., 30 min before stroke and once a day for three days after stroke) reduced Evans blue leakage and brain edema after ischemia. The expression of the BBB integrity markers, occludin, alpha-catenin and beta-catenin, in the brain was preserved in animals received rhEPO. rhEPO up-regulated VEGF expression; however, the expression of VEGF receptor-2 (fetal liver kinase receptor, Flk-1) was significantly reduced in rhEPO-treated animals three days after stroke. We propose that, disregarding increased VEGF levels, rhEPO protects against ischemia-induced BBB damage at least partly by down-regulating Flk-1 expression and the response to VEGF signaling in the acute phase after stroke.

Topics: Animals; Blood-Brain Barrier; Brain Edema; Cerebrovascular Circulation; Down-Regulation; Erythropoietin; Evans Blue; Fluorescent Antibody Technique; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Male; Membrane Proteins; Mice; Microscopy, Confocal; Occludin; Recombinant Proteins; Stroke; Vascular Endothelial Growth Factor Receptor-2

Erythropoietin (EPO) has recently been shown to have a neuroprotective effect in animal models of traumatic brain injury (TBI). However, the precise mechanisms remain unclear. Cerebral inflammation plays an important role in the pathogenesis of secondary brain injury after TBI. We, therefore, tried to analyze how recombinant human erythropoietin (rhEPO) might effect the inflammation-related factors common to TBI: nuclear factor kappa B (NF-kappaB), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) in a rat TBI model. Male rats were given 0 or 5000 units/kg injections of rhEPO 1h post-injury and on days 1, 2 and 3 after surgery. Brain samples were extracted at 3 days after trauma. We measured NF-kappaB by electrophoretic mobility shift assay (EMSA); IL-1beta, TNF-alpha and IL-6 by enzyme-linked immunosorbent assay (ELISA); ICAM-1 by immunohistochemistry; brain edema by wet/dry method; blood-brain barrier (BBB) permeability by Evans blue extravasation and cortical apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method. We found that NF-kappaB, pro-inflammatory cytokines and ICAM-1 were increased in all injured animals. In animals given rhEPO post-TBI, NF-kappaB, IL-1beta, TNF-alpha and ICAM-1 were decreased in comparison to vehicle-treated animals. Measures of IL-6 showed no change after rhEPO treatment. Administration of rhEPO reduced brain edema, BBB permeability and apoptotic cells in the injured brain. In conclusion, post-TBI rhEPO administration may attenuate inflammatory response in the injured rat brain, and this may be one mechanism by which rhEPO improves outcome following TBI.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Blood-Brain Barrier; Brain Edema; Brain Injuries; Cerebral Cortex; Cytoprotection; Disease Models, Animal; Encephalitis; Erythropoietin; Humans; Inflammation Mediators; Intercellular Adhesion Molecule-1; Interleukin-1beta; Interleukin-6; Male; Neuroprotective Agents; NF-kappa B; Rats; Rats, Wistar; Recombinant Proteins; Treatment Outcome; Tumor Necrosis Factor-alpha

A large body of evidence indicates that the hormone erythropoietin (EPO) exerts beneficial effects in the central nervous system (CNS). To date, EPO's effect has been assessed in several experimental models of brain and spinal cord injury. This study was conducted to validate whether treatment with recombinant human EPO (rHuEPO) would limit the extent of injury following experimental TBI. Experimental TBI was induced in rats by a cryogenic injury model. rHuEPO or placebo was injected intraperitoneally immediately after the injury and then every 8 h until 2 or 14 days. Forty-eight hours after injury brain water content, an indicator of brain edema, was measured with the wet-dry method and blood-brain barrier (BBB) breakdown was evaluated by assay of Evans blue extravasation. Furthermore, extent of cerebral damage was assessed. Administration of rHuEPO markedly improved recovery from motor dysfunction compared with placebo group (P<0.05). Brain edema was significantly reduced in the cortex of the EPO-treated group relative to that in the placebo-treated group (80.6+/-0.3% versus 91.8%+/-0.8% respectively, P<0.05). BBB breakdown was significantly lower in EPO-treated group than in the placebo-treated group (66.2+/-18.7 mug/g versus 181.3+/-21 mug/g, respectively, P<0.05). EPO treatment reduced injury volume significantly compared with placebo group (17.4+/-5.4 mm3 versus 37.1+/-5.3 mm3, P<0.05). EPO, administered in its recombinant form, affords significant neuroprotection in experimental TBI model and may hold promise for future clinical applications.

Topics: Analysis of Variance; Animals; Blood-Brain Barrier; Brain Edema; Brain Infarction; Brain Injuries; Disease Models, Animal; Erythropoietin; Evans Blue; Functional Laterality; Humans; Male; Neurologic Examination; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Reaction Time; Recombinant Proteins; Time Factors

Erythropoietin (EPO), a pleiotropic cytokine involved in erythropoiesis, is tissue-protective in ischemic, traumatic, toxic and inflammatory injuries. In this study, we investigated the effect of EPO in experimental intracerebral hemorrhage (ICH). Two hours after inducing ICH via the stereotaxic infusion of collagenase, recombinant human EPO (500 or 5000 IU/kg, ICH + EPO group) or PBS (ICH + vehicle group) was administered intraperitoneally, then once daily afterwards for 1 or 3 days. ICH + EPO showed the better functional recovery in both rotarod and modified limb placing tests. The brain water content was decreased in ICH + EPO dose-dependently, as compared with ICH + vehicle. The effect of EPO on the brain water content was inhibited by N(omega)-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 10 mg/kg). Mean hemorrhage volume was also decreased in ICH + EPO. EPO reduced the numbers of TUNEL +, myeloperoxidase + or OX-42 + cells in the perihematomal area. In addition, EPO reduced the mRNA level of TNF-alpha, Fas and Fas-L, as well as the activities of caspase-8, 9 and 3. EPO treatment showed up-regulations of endothelial nitric oxide synthase (eNOS) and p-eNOS, pAkt, pSTAT3 and pERK levels. These data suggests that EPO treatment in ICH induces better functional recovery with reducing perihematomal inflammation and apoptosis, coupled with activations of eNOS, STAT3 and ERK.

Topics: Animals; Apoptosis; Biomarkers; Body Water; Brain; Brain Edema; Cell Death; Cerebral Hemorrhage; Disease Models, Animal; Dose-Response Relationship, Drug; Encephalitis; Enzyme Activation; Enzyme Inhibitors; Erythropoietin; Male; Nerve Degeneration; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase Type III; Rats; Rats, Sprague-Dawley; Recovery of Function; Signal Transduction; STAT3 Transcription Factor; Treatment Outcome

Darbepoetin alfa is a novel erythropoiesis-stimulating protein developed for treating anemia. In animal models, exogenous recombinant human erythropoietin has been reported to be beneficial in treating experimental cerebral ischemia. In this study, we determined whether darbepoetin alfa would protect in a rat model of transient focal cerebral ischemia.. Rats received 2-hour middle cerebral artery suture-occlusion. The drug (darbepoetin alfa, 10 microg/kg) or vehicle was administered intraperitoneally 2 hours after onset of middle cerebral artery occlusion. Animals were allowed to survive for 3 or 14 days. Behavioral tests were performed sequentially. Infarct volumes and brain swelling were determined.. Darbepoetin alfa-treated rats showed improved neuroscores relative to vehicle-treated animals beginning within 1 hour of treatment and persisting throughout the 14-day survival period. Darbepoetin alfa significantly reduced corrected total (cortical + subcortical) infarct volume (56.3+/-20.6 and 110.8+/-6.8 mm3, respectively) and total infarct areas at multiple levels compared with vehicle in the 14-day survival group. Brain swelling was not affected by treatment.. Darbepoetin alfa confers behavioral and histological neuroprotection after focal ischemia in rats.

Topics: Animals; Behavior, Animal; Brain Edema; Brain Ischemia; Darbepoetin alfa; Erythropoietin; Infarction, Middle Cerebral Artery; Male; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Recombinant Proteins

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

Erythropoietin prevents in vitro glutamate-induced neuronal death and could play a role in the central nervous system. We investigated the in vivo effects of recombinant human erythropoietin after intraperitoneal (i.p.; 25-100 U) or intracerebroventricular (i.c.v.; 0.25-25 U) administration on survival, brain malonildialdehyde (MDA) levels, brain edema, hippocampal neuronal death and brain nitric oxide (NO) synthesis after bilateral carotid occlusion (5 min), followed by reperfusion in the Mongolian gerbil. Peripheral posttreatment with recombinant human erythropoietin reduced postischemic MDA levels, brain edema and increased survival. Either peripheral or i.c.v. posttreatment with recombinant human erythropoietin significantly reduced hippocampal CA1 neuronal loss, observed 7 days after the ischemic event. Increase of nitrite and nitrate (as an index of NO formation) in the hippocampus, as observed after ischemia, was reduced in animals treated with recombinant human erythropoietin. These data suggest that in vivo recombinant human erythropoietin effects on brain ischemic injury could be due to inhibition of NO overproduction.

Topics: Aldehydes; Animals; Brain; Brain Edema; Brain Ischemia; Erythropoietin; Gerbillinae; Humans; Injections, Intraperitoneal; Injections, Intraventricular; Male; Neurons; Nitrates; Nitric Oxide; Nitrites; Recombinant Proteins; Survival Rate

Human recombinant erythropoietin (r-huEPO) is very effective in the treatment of anemia of hemodialyzed patients. We describe 4 patients who developed symptoms of central nervous dysfunction during r-huEPO therapy. Three exhibited typical hypertensive encephalopathy, whereas signs of cerebral ischemia were found in the fourth. The increase in blood viscosity with r-huEPO treatment, leading to a rise in peripheral vascular resistance and blood pressure especially in previously hypertensive patients, may be of importance in the pathogenesis of these cerebrovascular incidents; preexistent arteriosclerosis is an possible additional risk factor.

Topics: Adult; Aged; Anemia, Hemolytic; Blood Viscosity; Brain Edema; Brain Ischemia; Cerebrovascular Disorders; Erythropoietin; Female; Humans; Male; Middle Aged; Recombinant Proteins; Renal Dialysis