Recent trends in erythropoietin-mediated neuroprotection

Effects of cannabidiol in post-stroke mood disorders in neonatal rats

BACKGROUND

Neonatal rats can manifest post-stroke mood disorders (PSMD) following middle cerebral artery occlusion (MCAO). We investigated whether cannabidiol (CBD) neuroprotection, previously demonstrated in neonatal rats after MCAO, includes prevention of PSMD development.

METHODS

Seven-day-old Wistar rats (P7) underwent MCAO and received either vehicle or 5 mg/kg CBD treatment. Brain damage was quantified by MRI, and neurobehavioral and histological (TUNEL) studies were performed at P14 and P37. PSMD were assessed using the tail suspension test, forced swimming test, and open field tests. The dopaminergic system was evaluated by quantifying dopaminergic neurons (TH+) in the Ventral Tegmental Area (VTA), measuring brain dopamine (DA) concentration and DA transporter expression, and assessing the expression and function D2 receptors (D2R) through [35S]GTPγS binding. Animals without MCAO served as controls.

RESULTS

CBD reduced MCAO-induced brain damage and improved motor performance. At P14, MCAO induced depressive-like behavior, characterized by reduced TH+ cell population and DA levels, which CBD did not prevent. However, CBD ameliorated hyperactivity observed at P37, preventing increased DA concentration by restoring D2R function.

CONCLUSIONS

These findings confirm the development of PSMD following MCAO in neonatal rats and highlight CBD as a neuroprotective agent capable of long-term functional normalization of the dopaminergic system post-MCAO.

IMPACT

MCAO in neonatal rats led to post-stroke mood disorders consisting in a depression-like picture in the medium term evolving towards long-term hyperactivity, associated with an alteration of the dopaminergic system. The administration of CBD after MCAO did not prevent the development of depressive-like behavior, but reduced long-term hyperactivity, normalizing dopamine receptor function. These data point to the importance of considering the development of depression-like symptoms after neonatal stroke, a well-known complication after stroke in adults. Our work confirms the interest of CBD as a possible treatment for neonatal stroke.

NeuroEPO plus (NeuralCIM®) in mild-to-moderate Alzheimer's clinical syndrome: the ATHENEA randomized clinical trial

BACKGROUND

NeuroEPO plus is a recombinant human erythropoietin without erythropoietic activity and shorter plasma half-life due to its low sialic acid content. NeuroEPO plus prevents oxidative damage, neuroinflammation, apoptosis and cognitive deficit in an Alzheimer's disease (AD) models. The aim of this study was to assess efficacy and safety of neuroEPO plus.

METHODS

This was a double-blind, randomized, placebo-controlled, phase 2-3 trial involving participants ≥ 50 years of age with mild-to-moderate AD clinical syndrome. Participants were randomized in a 1:1:1 ratio to receive 0.5 or 1.0 mg of neuroEPO plus or placebo intranasally 3 times/week for 48 weeks. The primary outcome was change in the 11-item cognitive subscale of the AD Assessment Scale (ADAS-Cog11) score from baseline to 48 weeks (range, 0 to 70; higher scores indicate greater impairment). Secondary outcomes included CIBIC+, GDS, MoCA, NPI, Activities of Daily Living Scales, cerebral perfusion, and hippocampal volume.

RESULTS

A total of 174 participants were enrolled and 170 were treated (57 in neuroEPO plus 0.5 mg, 56 in neuroEPO plus 1.0 mg and 57 in placebo group). Mean age, 74.0 years; 121 (71.2%) women and 85% completed the trial. The median change in ADAS-Cog11 score at 48 weeks was -3.0 (95% CI, -4.3 to -1.7) in the 0.5 mg neuroEPO plus group, -4.0 (95% CI, -5.9 to -2.1) in the 1.0 mg neuroEPO plus group and 4.0 (95% CI, 1.9 to 6.1) in the placebo group. The difference of neuroEPO plus 0.5 mg vs. placebo was 7.0 points (95% CI, 4.5-9.5) P = 0.000 and between the neuroEPO plus 1.0 mg vs. placebo was 8.0 points (95% CI, 5.2-10.8) P = 0.000. NeuroEPO plus treatment induced a statistically significant improvement in some of clinical secondary outcomes vs. placebo including CIBIC+, GDS, MoCA, NPI, and the brain perfusion.

CONCLUSIONS

Among participants with mild-moderate Alzheimer's disease clinical syndrome, neuroEPO plus improved the cognitive evaluation at 48 weeks, with a very good safety profile. Larger trials are warranted to determine the efficacy and safety of neuroEPO plus in Alzheimer's disease.

TRIAL REGISTRATION

https://rpcec.sld.cu Identifier: RPCEC00000232.

The Role of the Dopamine System in Post-Stroke Mood Disorders in Newborn Rats

Post-stroke mood disorders (PSMD) affect disease prognosis in adults. Adult rodent models underlie the importance of the dopamine (DA) system in PSMD pathophysiology. There are no studies on PSMD after neonatal stroke. We induced neonatal stroke in 7-day-old (P7) rats by temporal left middle cerebral artery occlusion (MCAO). Performance in the tail suspension test (TST) at P14 and the forced swimming test (FST) and open field test (OFT) at P37 were studied to assess PSMD. DA neuron density in the ventral tegmental area, brain DA concentration and DA transporter (DAT) expression as well as D2 receptor (D2R) expression and G-protein functional coupling were also studied. MCAO animals revealed depressive-like symptoms at P14 associated with decreased DA concentration and reduced DA neuron population and DAT expression. At P37, MCAO rats showed hyperactive behavior associated with increased DA concentration, normalization of DA neuron density and decreased DAT expression. MCAO did not modify D2R expression but reduced D2R functionality at P37. MCAO-induced depressive-like symptoms were reversed by the DA reuptake inhibitor GBR-12909. In conclusion, MCAO in newborn rats induced depressive-like symptoms and hyperactive behavior in the medium and long term, respectively, that were associated with alterations in the DA system.

The Effect of Neuroepo on Cognition in Parkinson’s Disease Patients Is Mediated by Electroencephalogram Source Activity

We report on the quantitative electroencephalogram (qEEG) and cognitive effects of Neuroepo in Parkinson’s disease (PD) from a double-blind safety trial (https://clinicaltrials.gov/, number NCT04110678). Neuroepo is a new erythropoietin (EPO) formulation with a low sialic acid content with satisfactory results in animal models and tolerance in healthy participants and PD patients. In this study, 26 PD patients were assigned randomly to Neuroepo (n = 15) or placebo (n = 11) groups to test the tolerance of the drug. Outcome variables were neuropsychological tests and resting-state source qEEG at baseline and 6 months after administering the drug. Probabilistic Canonical Correlation Analysis was used to extract latent variables for the cognitive and for qEEG variables that shared a common source of variance. We obtained canonical variates for Cognition and qEEG with a correlation of 0.97. Linear Mixed Model analysis showed significant positive dependence of the canonical variate cognition on the dose and the confounder educational level (p = 0.003 and p = 0.02, respectively). Additionally, in the mediation equation, we found a positive dependence of Cognition with qEEG for (p = < 0.0001) and with dose (p = 0.006). Despite the small sample, both tests were powered over 89%. A combined mediation model showed that 66% of the total effect of the cognitive improvement was mediated by qEEG (p = 0.0001), with the remaining direct effect between dose and Cognition (p = 0.002), due to other causes. These results suggest that Neuroepo has a positive influence on Cognition in PD patients and that a large portion of this effect is mediated by brain mechanisms reflected in qEEG.

Cerebral Erythropoietin Prevents Sex-Dependent Disruption of Respiratory Control Induced by Early Life Stress

Injuries that occur early in life are often at the root of adult illness. Neonatal maternal separation (NMS) is a form of early life stress that has persistent and sex-specific effects on the development of neural networks, including those that regulate breathing. The release of stress hormones during a critical period of development contributes to the deleterious consequences of NMS, but the role of increased corticosterone (CORT) in NMS-induced respiratory disturbance is unknown. Because erythropoietin (EPO) is a potent neuroprotectant that prevents conditions associated with hyperactivation of the stress neuroaxis in a sex-specific manner, we hypothesized that EPO reduces the sex-specific alteration of respiratory regulation induced by NMS in adult mice. Animals were either raised under standard conditions (controls) or exposed to NMS 3 h/day from postnatal days 3–12. We tested the efficacy of EPO in preventing the effects of NMS by comparing wild-type mice with transgenic mice that overexpress EPO only in the brain (Tg21). In 7-days-old pups, NMS augmented CORT levels ~2.5-fold by comparison with controls but only in males; this response was reduced in Tg21 mice. Respiratory function was assessed using whole-body plethysmography. Apneas were detected during sleep; the responsiveness to stimuli was measured by exposing mice to hypoxia (10% O₂; 15 min) and hypercapnia (5% CO₂; 10 min). In wild-type, NMS increased the number of apneas and the hypercapnic ventilatory response (HcVR) only in males; with no effect on Tg21. In wild-type males, the incidence of apneas was positively correlated with HcVR and inversely related to the tachypneic response to hypoxia. We conclude that neural EPO reduces early life stress-induced respiratory disturbances observed in males.

Erythropoietin Produces a Dual Effect on Carotid Body Chemoreception in Male Rats

Erythropoietin (EPO) regulates respiration under conditions of normoxia and hypoxia through interaction with the respiratory centers of the brainstem. Here we investigate the dose-dependent impact of EPO in the CB response to hypoxia and hypercapnia. We show, in isolated "en bloc" carotid body (CB) preparations containing the carotid sinus nerve (CSN) from adult male Sprague Dawley rats, that EPO acts as a stimulator of CSN activity in response to hypoxia at concentrations below 0.5 IU/ml. Under hypercapnic conditions, EPO did not influence the CSN response. EPO concentrations above 0.5 IU/ml decreased the response of the CSN to both hypoxia and hypercapnia, reaching complete inhibition at 2 IU/ml. The inhibitory action of high-dose EPO on the CSN activity might result from an increase in nitric oxide (NO) production. Accordingly, CB preparations were incubated with 2 IU/ml EPO and the unspecific NO synthase inhibitor (L-NAME), or the neuronal-specific NO synthase inhibitor (7NI). Both NO inhibitors fully restored the CSN activity in response to hypoxia and hypercapnia in presence of EPO. Our results show that EPO activates the CB response to hypoxia when its concentration does not exceed the threshold at which NO inhibitors masks EPO's action.

Diagnostic Performance of Erythropoietin and Erythropoietin Receptors Levels in Children with Attention Deficit Hyperactivity Disorder

Objective

Attention deficit hyperactivity disorder (ADHD) is a heterogeneous, highly heritable, a common childhood neurobehavioural disorder resulting from complex gene-gene and gene-environment interactions. The erythropoietin (Epo)/erythropoietin receptors (EpoR) system turned out to have additional important functions in nonhematopoietic tissue. In this study, we aimed to investigate the levels of Epo and and EpoR, and also their diagnostic values in children with ADHD.

Methods

A total of 70 children were included in the study, 35 drug-naive patients with ADHD (age 6−12 years; male/female 20/15) and 35 healthy controls (age 6−12 years; male/female 22/13). Serum Epo and EpoR levels was determined using a commercial sandwich enzyme-linked immunosorbent assay kit.

Results

The results indicated that the levels of Epo decreased in patients with ADHD compared to control (p < 0.05). On the other hand, EpoR levels increased in these patients (p < 0.05). Furthermore, the ratio of Epo/EpoR was significantly lower in ADHD patients than controls (p < 0.05). Receiver operator characteristic curve analysis showed high diagnostic performance for Epo and EpoR, areas under curve were 0.980 and 1.000, respectively.

Conclusion

This is the first report to investigate the association between serum Epo and EpoR levels in ADHD patients. Our results indicated that Epo may play a role in the etiology of ADHD, and Epo therapy may be beneficial in these disorders if given in addition to the routine treatment of children with ADHD. Furthermore, our results reveal possible diagnostic value of Epo and EpoR.

Insights into Potential Targets for Therapeutic Intervention in Epilepsy

Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.

Hypoxia-Associated Changes in Striatal Tonic Dopamine Release: Real-Time in vivo Measurements With a Novel Voltammetry Technique

Introduction

Striatal tonic dopamine increases rapidly during global cerebral hypoxia. This phenomenon has previously been studied using microdialysis techniques which have relatively poor spatio-temporal resolution. In this study, we measured changes in tonic dopamine during hypoxia (death) in real time with high spatio-temporal resolution using novel multiple cyclic square wave voltammetry (MCSWV) and conventional fast scan cyclic voltammetry (FSCV) techniques.

Methods

MCSWV and FSCV were used to measure dopamine release at baseline and during hypoxia induced by euthanasia, with and without prior alpha-methyl-p-tyrosine (AMPT) treatment, in urethane anesthetized male Sprague-Dawley rats.

Results

Baseline tonic dopamine levels were found to be 274.1 ± 49.4 nM (n = 5; mean ± SEM). Following intracardiac urethane injection, the tonic levels increased to a peak concentration of 1753.8 ± 95.7 nM within 3.6 ± 0.6 min (n = 5), followed by a decline to 50.7 ± 21.5 nM (n = 4) at 20 min. AMPT pre-treatment significantly reduced this dopamine peak to 677.9 ± 185.7 nM (n = 3). FSCV showed a significantly higher (p = 0.0079) peak dopamine release of 6430.4 ± 1805.7 nM (n = 5) during euthanasia-induced cerebral hypoxia.

Conclusion

MCSWV is a novel tool to study rapid changes in tonic dopamine release in vivo during hypoxia. We found a 6-fold increase in peak dopamine levels during hypoxia which was attenuated with AMPT pre-treatment. These changes are much lower compared to those found with microdialysis. This could be due to improved estimation of baseline tonic dopamine with MCSWV. Higher dopamine response measured with FSCV could be due to an increased oxidation current from electroactive interferents.

Prenatal Hypoxia and Placental Oxidative Stress: Insights from Animal Models to Clinical Evidences

Hypoxia is a common form of intrauterine stress characterized by exposure to low oxygen concentrations. Gestational hypoxia is associated with the generation of reactive oxygen species. Increase in oxidative stress is responsible for damage to proteins, lipids and DNA with consequent impairment of normal cellular functions. The purpose of this review is to propose a summary of preclinical and clinical evidences designed to outline the correlation between fetal hypoxia and oxidative stress. The results of the studies described show that increases of oxidative stress in the placenta is responsible for changes in fetal development. Specifically, oxidative stress plays a key role in vascular, cardiac and neurological disease and reproductive function dysfunctions. Moreover, the different finding suggests that the prenatal hypoxia-induced oxidative stress is associated with pregnancy complications, responsible for changes in fetal programming. In this way, fetal hypoxia predisposes the offspring to congenital anomalies and chronic diseases in future life. Several antioxidant agents, such as melatonin, erythropoietin, vitamin C, resveratrol and hydrogen, shown potential protective effects in prenatal hypoxia. However, future investigations will be needed to allow the implementation of these antioxidants in clinical practice for the promotion of health in early intrauterine life, in fetuses and children.

Hematologic safety of chronic brain-penetrating erythropoietin dosing in APP/PS1 mice

Introduction

Low blood-brain barrier (BBB) penetration and hematopoietic side effects limit the therapeutic development of erythropoietin (EPO) for Alzheimer's disease (AD). A fusion protein of EPO and a chimeric monoclonal antibody targeting the mouse transferrin receptor (cTfRMAb) has been engineered. The latter drives EPO into the brain via receptor-mediated transcytosis across the BBB and increases its peripheral clearance to reduce hematopoietic side effects of EPO. Our previous work shows the protective effects of this BBB-penetrating EPO in AD mice but hematologic effects have not been studied. Herein, we investigate the hematologic safety and therapeutic effects of chronic cTfRMAb-EPO dosing, in comparison to recombinant human EPO (rhu-EPO), in AD mice.

Methods

Male APPswe PSEN1dE9 (APP/PS1) mice (9.5 months) were treated with saline (n = 11), and equimolar doses of cTfRMAb-EPO (3 mg/kg, n = 7), or rhu-EPO (0.6 mg/kg, n = 9) 2 days/week subcutaneously for 6 weeks, compared to saline-treated wild-type mice (n = 10). At 6 weeks, exploration and memory were assessed, and mice were sacrificed at 8 weeks. Spleens were weighed, and brains were evaluated for amyloid beta (Aβ) load and synaptophysin. Blood was collected at 4, 6 and 8 weeks for a complete blood count and white blood cells differential.

Results

cTfRMAb-EPO transiently increased reticulocyte counts after 4 weeks, followed by normalization of reticulocytes at 6 and 8 weeks. rhu-EPO transiently increased red blood cell count, hemoglobin and hematocrit, and significantly decreased mean corpuscular volume and reticulocytes at 4 weeks, which remained low at 6 weeks. At 8 weeks, a significant decline in red blood cell indices was observed with rhu-EPO treatment. Exploration and cognitive deficits were significantly worse in APP/PS1-rhu-EPO mice. Both cTfRMAb-EPO and rhu-EPO decreased 6E10-positive brain Aβ load; however, cTfRMAb-EPO and not rhu-EPO selectively reduced brain Aβ_1-42 and elevated synaptophysin expression.

Discussion

Chronic treatment with cTfRMAb-EPO results in better hematologic safety, behavioral, and therapeutic indices compared with rhu-EPO, supporting the development of this BBB-penetrable EPO analog for AD.

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Chimeric monoclonal antibody against the mouse TfR (cTfRMAb)-erythropoietin (EPO) is a brain-penetrating IgG-EPO fusion protein.

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Chronic treatment with cTfRMAb-EPO does not alter hematology indices in APP/PS1 mice.

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Equimolar dose of recombinant human EPO significantly alters hematologic indices in APP/PS1 mice.

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Both cTfRMAb-EPO and recombinant human EPO reduce amyloid beta load in APP/PS1 mice.

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cTfRMAb-EPO selectively reduces amyloid beta (1–42) and increases synaptophysin in APP/PS1 mice.

Erythropoietin in Treatment of Methanol Optic Neuropathy

BACKGROUND

Methanol poisoning can cause an optic neuropathy that is usually severe and irreversible and often occurs after ingestion of illicit or homemade alcoholic beverages. In this study, we evaluated the potential neuroprotective effect of erythropoietin (EPO) on visual acuity (VA) in patients with methanol optic neuropathy.

METHODS

In a prospective, noncomparative interventional case series, consecutive patients with methanol optic neuropathy after alcoholic beverage ingestion were included. All patients initially received systemic therapy including metabolic stabilization and detoxification. Treatment with intravenous recombinant human EPO consisted of 20,000 units/day for 3 successive days. Depending on clinical response, some patients received a second course of EPO. VA, funduscopy, and spectral domain optical coherence tomography were assessed during the study. Main outcome measure was VA.

RESULTS

Thirty-two eyes of 16 patients with methanol optic neuropathy were included. Mean age was 34.2 years (±13.3 years). The mean time interval between methanol ingestion and treatment with intravenous EPO was 9.1 days (±5.56 days). Mean follow-up after treatment was 7.5 months (±5.88 months). Median VA in the better eye of each patient before treatment was light perception (range: 3.90-0.60 logMAR). Median last acuity after treatment in the best eye was 1.00 logMAR (range: 3.90-0.00 logMAR). VA significantly increased in the last follow-up examination (P < 0.0001). Age and time to EPO treatment after methanol ingestion were not significantly related to final VA. No ocular or systemic complications occurred in our patient cohort.

CONCLUSIONS

Intravenous EPO appears to improve VA in patients with methanol optic neuropathy and may represent a promising treatment for this disorder.

Effects of erythropoietin on bile duct ligation-induced neuro-inflammation in male rats

Hepatic encephalopathy (HE) is a brain disorder as a result of liver failure. Previous studies have indicated that erythropoietin (EPO) has neuroprotective effects in different neurological diseases. This study addressed the therapeutic effect of a four-week treatment with EPO on neuronal damages in bile duct-ligated rats. Forty male Wistar rats (250–280 g) were used in the present study. The animals were randomly divided into four groups consisting of 10 animals each, including sham, sham + EPO, bile duct ligation (BDL), and BDL + EPO. EPO was intraperitoneally administered every other day (5,000 U/Kg) in the last four weeks after BDL. Biochemical and histological studies were performed to evaluate neurodegeneration. The results revealed that BDL increases the level of hepatic enzymes and total bilirubin. Furthermore, neurodegeneration was significantly increased in the BDL group compared to sham groups. EPO preserved hepatic enzymes and total bilirubin in the treated group. In addition, EPO significantly decreased the neurodegeneration in BDL + EPO compared to the BDL group. Results of this study showed that EPO has neuroprotective effects in the rat model of HE, possibly due to its anti-inflammatory and anti-oxidant properties. Complementary studies are required to clarify the exact mechanisms.

Hypoxia and myelination deficits in the developing brain

Myelination is a complex and orderly process during brain development that is essential for normal motor, cognitive and sensory functions. Cellular and molecular interactions between myelin-forming oligodendrocytes and axons are required for normal myelination in the developing brain. Oligodendrocyte progenitor cells (OPCs) proliferate and differentiate into mature myelin-forming oligodendrocytes. In this connection, astrocytes and microglia are also involved in survival and proliferation of OPCs. Hypoxic insults during the perinatal period affect the normal development, differentiation and maturation of the OPCs or cause their death resulting in impaired myelination. Several factors such as augmented release of proinflammatory cytokines by activated microglia and astrocytes, extracellular accumulation of excess glutamate and increased levels of nitric oxide are some of the underlying factors for hypoxia induced damage to the OPCs. Additionally, hypoxia also leads to down-regulation of several genes involved in oligodendrocyte differentiation encoding proteolipid protein, platelet-derived growth factor receptor and myelin-associated glycoprotein in the developing brain. Furthermore, oligodendrocytes may also accumulate increased amounts of iron in hypoxic conditions that triggers endoplasmic reticulum stress, misfolding of proteins and generation of reactive oxygen species that ultimately would lead to myelination deficits. More in-depth studies to elucidate the pathophysiological mechanisms underlying the inability of oligodendrocytes to myelinate the developing brain in hypoxic insults are desirable to develop new therapeutic options or strategies for myelination deficits.

Erythropoietin: A potential drug in the management of diabetic neuropathy

Erythropoietin (EPO) is required for promoting the progress of erythroid differentiation. However, the discovery of EPO and the EPO receptor (EPOR) in the nervous system may contribute to new treatment strategies for the use of EPO in neurodegenerative disorders. Diabetic neuropathy is a neurodegenerative disease that affects a large proportion of diabetic patients and results in alterations in functionality, mood and sleep. The pathogenic mechanisms generating diabetic neuropathy involve: Schwannopathy, polyol pathway activity, advanced glycation end-products (AGEs) accumulation, protein kinase C (PKC) activity, increased hexosamine pathway flux, oxidative stress, nitric oxide and inflammation. In this sense, evidence from both clinical and experimental studies indicates that EPO may reverse diabetic neuropathy through an antioxidant action by decreasing pro-inflammatory cytokines, restoring Na+/K+-ATPase activity, and blocking the generation of pro-apoptotic proteins. The aim of this review is to discuss the neuroprotector effect of EPO on pathogenic mechanisms of diabetic neuropathy.

Protective Activity of Erythropoyetine in the Cognition of Patients with Parkinson's Disease

Introduction: Treatment strategies in Parkinson’s disease (PD) can improve a patient’s quality of life but cannot stop the progression of PD. We are looking for different alternatives that modify the natural course of the disease and recent research has demonstrated the neuroprotective properties of erythropoietin. In Cuba, the Center for Molecular Immunology (CIM) is a cutting edge scientific center where the recombinant form (EPOrh) and recombinant human erythropoietin with low sialic acid (NeuroEPO) are produced. We performed two clinical trials to evaluate the safety and tolerability of these two drugs in PD patients. In this paper we want to show the positive results of the additional cognitive tests employed, as part of the comprehensive assessment. Materials and method: Two studies were conducted in PD patients from the outpatient clinic of CIREN, including n = 10 and n = 26 patients between 60 and 66 years of age, in stages 1 to 2 of the Hoehn and Yahr Scale. The first study employed recombinant human (rhEPO) and the second an intranasal formulation of neuroEPO. All patients were evaluated with a battery of neuropsychological scales composed to evaluate global cognitive functioning, executive function, and memory. Results: The general results in both studies showed a positive response to the cognitive functions in PD patients, who were undergoing pharmacological treatment with respect to the evaluation (p < 0.05) before the intervention. Conclusions: Erythropoietin has a discrete positive effect on the cognitive functions of patients with Parkinson’s disease, which could be interpreted as an effect of the neuroprotective properties of this molecules. To confirm the results another clinical trial phase III with neuroEPO is in progress, also designed to discard any influence of a placebo effect on cognition.

Erythropoietin: Endogenous Protection of Ischemic Brain

The human brain requires uninterrupted delivery of blood-borne oxygen and nutrients to sustain its function. Focal ischemia, particularly, ischemic stroke, and global ischemia imposed by cardiac arrest disrupt the brain's fuel supply. The resultant ATP depletion initiates a complex injury cascade encompassing intracellular Ca²⁺ overload, glutamate excitotoxicity, oxido-nitrosative stress, extracellular matrix degradation, and inflammation, culminating in neuronal and astroglial necrosis and apoptosis, neurocognitive deficits, and even death. Unfortunately, brain ischemia has proven refractory to pharmacological intervention. Many promising treatments afforded brain protection in animal models of focal and global ischemia, but failed to improve survival and neurocognitive recovery of stroke and cardiac arrest patients in randomized clinical trials. The culprits are the blood-brain barrier (BBB) that limits transferral of medications to the brain parenchyma, and the sheer complexity of the injury cascade, which presents a daunting array of targets unlikely to respond to monotherapies. Erythropoietin is a powerful neuroprotectant capable of interrupting multiple aspects of the brain injury cascade. Preclinical research demonstrates erythropoietin's ability to suppress glutamate excitotoxicity and intracellular Ca²⁺ overload, dampen oxidative stress and inflammation, interrupt the apoptotic cascade, and preserve BBB integrity. However, the erythropoietin dosages required to traverse the BBB and achieve therapeutically effective concentrations in the brain parenchyma impose untoward side effects. Recent discoveries that hypoxia induces erythropoietin production within the brain and that neurons, astroglia, and cerebrovascular endothelium harbor membrane erythropoietin receptors, raise the exciting prospect of harnessing endogenous erythropoietin to protect the brain from the ravages of ischemia-reperfusion.

A meta-analysis of the protective effect of recombinant human erythropoietin (rhEPO) for neurodevelopment in preterm infants

The purpose of this study is to assess the efficacy and safety of recombinant human erythropoietin (rhEPO) for improving neurodevelopment outcomes in preterm infants. According to the requirements of Cochrane systematic review, a literature search was performed among PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, Wan Fang Data, and VIP INFORMATION from the establishment of the database from January 1999 to December 2011. Quality assessments of clinical trials were carried out. Randomized controlled trials (RCTs) or quasi-RCTs with rhEPO in preterm infants were enrolled, and RevMan5.0 software was used for meta-analysis. Data extraction, quality assessment, and meta-analysis for the results of homogeneous studies were done by two reviewers. The trials were analyzed using weighted mean difference (WMD) for continuous data and odds ratio (OR) for dichotomous data, both kinds of data were expressed by 95 % CI. For homogenous data (P ≥ 0.10), fixed effect model was calculated. Two RCTs and 3 quasi-RCTs including 233 preterm infants (119 of treatment group and 114 of control group) were included in the analysis. The results of quality assessment were that 1 study was A, 1 was B, and 3 were C. There was evidence of a significant effect of therapeutic rhEPO on the outcomes of MDI scores [WMD = 7.77, 95 % CI (3.49-12.06), P = 0.0004], PDI scores [WMD = 3.85, 95 % CI (0.62-7.09), P = 0.02] at 18-22 months and NBNA scores [WMD = 1.96, 95 % CI (1.56-2.37), P < 0.00001] at 40 weeks of corrected gestational age. However, rhEPO had no effect on MDI <70 (OR = 0.70, 95 % CI 0.31-1.61), PDI <70 (OR = 2. 46, 95 % CI 0.94-6.45), cerebral palsy (OR = 1.08, 95 % CI 0.39-2.99), blindness (OR = 0.34, 95 % CI 0.01-8.56), and hearing loss (OR = 1.04, 95 % CI 0.06-17.15). There were no differences between groups with respect to the percentage of preterm infants with severe retinopathy of prematurity of stage III or above (OR = 1.30, 95 % CI 0.50-3.43), severe intraventricular hemorrhage of stage III or above (OR = 2. 91, 95 % CI 0.64-13.23), necrotizing enterocolitis (OR = 0.57, 95 % CI 0.13-2.54), and borderline personality disorder (OR = 1. 06, 95 % CI 0.50-2.26). The rhEPO treatment has beneficial effect on the neurodevelopment outcomes without severe adverse side effect in preterm infants.

Systemic dendrimer-drug treatment of ischemia-induced neonatal white matter injury

Extreme prematurity is a major risk factor for perinatal and neonatal brain injury, and can lead to white matter injury that is a precursor for a number of neurological diseases, including cerebral palsy (CP) and autism. Neuroinflammation, mediated by activated microglia and astrocytes, is implicated in the pathogenesis of neonatal brain injury. Therefore, targeted drug delivery to attenuate neuroinflammation may greatly improve therapeutic outcomes in models of perinatal white matter injury. In this work, we use a mouse model of ischemia-induced neonatal white matter injury to study the biodistribution of generation 4, hydroxyl-functionalized polyamidoamine dendrimers. Following systemic administration of the Cy5-labeled dendrimer (D-Cy5), we demonstrate dendrimer uptake in cells involved in ischemic injury, and in ongoing inflammation, leading to secondary injury. The sub-acute response to injury is driven by astrocytes. Within five days of injury, microglial proliferation and migration occurs, along with limited differentiation of oligodendrocytes and oligodendrocyte death. From one day to five days after injury, a shift in dendrimer co-localization occurred. Initially, dendrimer predominantly co-localized with astrocytes, with a subsequent shift towards microglia. Co-localization with oligodendrocytes reduced over the same time period, demonstrating a region-specific uptake based on the progression of the injury. We further show that systemic administration of a single dose of dendrimer-N-acetyl cysteine conjugate (D-NAC) at either sub-acute or delayed time points after injury results in sustained attenuation of the 'detrimental' pro-inflammatory response up to 9days after injury, while not impacting the 'favorable' anti-inflammatory response. The D-NAC therapy also led to improvement in myelination, suggesting reduced white matter injury. Demonstration of treatment efficacy at later time points in the postnatal period provides a greater understanding of how microglial activation and chronic inflammation can be targeted to treat neonatal brain injury. Importantly, it may also provide a longer therapeutic window.

DNA methylation is necessary for erythropoietin to improve spatial learning and memory in SAMP8 mice

OBJECTIVE

To reveal the role of Dnmts in the improvement of spatial learning and memory induced by erythropoietin (EPO) in SAMP8 mice.

METHODS

The Morris water maze (MWM) was used to assess spatial learning and memory. Mice were administered by intraperitoneal (i.p.) injection of recombinant human EPO and hippocamppi infusion (IH) of 5-aza-2'-deoxycytidine (5-AZA). The expression of genes Dnmt1, Dnmt3a and Dnmt3b in the hippocampus was detected by real-time qPCR. The level of proteins DNMT1, DNMT3A and DNMT3B was measured by Western blotting.

RESULTS

Spatial learning and memory in SAMP8 were promoted after i.p. injection of EPO (5000IU/kg/day) and expression of Dnmt3b mRNA and DNMT3B proteins in the hippocampus increased. The improved memory by EPO was blocked after IH 5-AZA.

CONCLUSION

DNA methylation is necessary for EPO to enhance spatial learning and memory in SAMP8 mice.

Neuronal injury from cardiac arrest: aging years in minutes

Cardiac arrest is a leading cause of death and permanent disability. Most victims succumb to the oxidative and inflammatory damage sustained during cardiac arrest/resuscitation, but even survivors typically battle long-term neurocognitive impairment. Although extensive research has delineated the complex mechanisms that culminate in neuronal damage and death, no effective treatments have been developed to interrupt these mechanisms. Of importance, many of these injury cascades are also active in the aging brain, where neurons and other cells are under persistent oxidative and inflammatory stress which eventually damages or kills the cells. In light of these similarities, it is reasonable to propose that the brain essentially ages the equivalent of several years within the few minutes taken to resuscitate a patient from cardiac arrest. Accordingly, cardiac arrest-resuscitation models may afford an opportunity to study the deleterious mechanisms underlying the aging process, on an accelerated time course. The aging and resuscitation fields both stand to gain pivotal insights from one another regarding the mechanisms of injury sustained during resuscitation from cardiac arrest and during aging. This synergism between the two fields could be harnessed to foster development of treatments to not only save lives but also to enhance the quality of life for the elderly.

Multi-modal assessment of long-term erythropoietin treatment after neonatal hypoxic-ischemic injury in rat brain

Erythropoietin (EPO) has been recognized as a neuroprotective agent. In animal models of neonatal brain injury, exogenous EPO has been shown to reduce lesion size, improve structure and function. Experimental studies have focused on short course treatment after injury. Timing, dose and length of treatment in preterm brain damage remain to be defined. We have evaluated the effects of high dose and long-term EPO treatment in hypoxic-ischemic (HI) injury in 3 days old (P3) rat pups using histopathology, magnetic resonance imaging (MRI) and spectroscopy (MRS) as well as functional assessment with somatosensory-evoked potentials (SEP). After HI, rat pups were assessed by MRI for initial damage and were randomized to receive EPO or vehicle. At the end of treatment period (P25) the size of resulting cortical damage and white matter (WM) microstructure integrity were assessed by MRI and cortical metabolism by MRS. Whisker elicited SEP were recorded to evaluate somatosensory function. Brains were collected for neuropathological assessment. The EPO treated animals did not show significant decrease of the HI induced cortical loss at P25. WM microstructure measured by diffusion tensor imaging was improved and SEP response in the injured cortex was recovered in the EPO treated animals compared to vehicle treated animals. In addition, the metabolic profile was less altered in the EPO group. Long-term treatment with high dose EPO after HI injury in the very immature rat brain induced recovery of WM microstructure and connectivity as well as somatosensory cortical function despite no effects on volume of cortical damage. This indicates that long-term high-dose EPO induces recovery of structural and functional connectivity despite persisting gross anatomical cortical alteration resulting from HI.

Erythropoietin: powerful protection of ischemic and post-ischemic brain

Ischemic brain injury inflicted by stroke and cardiac arrest ranks among the leading causes of death and long-term disability in the United States. The brain consumes large amounts of metabolic substrates and oxygen to sustain its energy requirements. Consequently, the brain is exquisitely sensitive to interruptions in its blood supply, and suffers irreversible damage after 10-15 min of severe ischemia. Effective treatments to protect the brain from stroke and cardiac arrest have proven elusive, due to the complexities of the injury cascades ignited by ischemia and reperfusion. Although recombinant tissue plasminogen activator and therapeutic hypothermia have proven efficacious for stroke and cardiac arrest, respectively, these treatments are constrained by narrow therapeutic windows, potentially detrimental side-effects and the limited availability of hypothermia equipment. Mounting evidence demonstrates the cytokine hormone erythropoietin (EPO) to be a powerful neuroprotective agent and a potential adjuvant to established therapies. Classically, EPO originating primarily in the kidneys promotes erythrocyte production by suppressing apoptosis of proerythroid progenitors in bone marrow. However, the brain is capable of producing EPO, and EPO's membrane receptors and signaling components also are expressed in neurons and astrocytes. EPO activates signaling cascades that increase the brain's resistance to ischemia-reperfusion stress by stabilizing mitochondrial membranes, limiting formation of reactive oxygen and nitrogen intermediates, and suppressing pro-inflammatory cytokine production and neutrophil infiltration. Collectively, these mechanisms preserve functional brain tissue and, thus, improve neurocognitive recovery from brain ischemia. This article reviews the mechanisms mediating EPO-induced brain protection, critiques the clinical utility of exogenous EPO to preserve brain threatened by ischemic stroke and cardiac arrest, and discusses the prospects for induction of EPO production within the brain by the intermediary metabolite, pyruvate.

The AKT/mTOR pathway mediates neuronal protective effects of erythropoietin in sepsis

Sepsis is one of the most common causes of mortality in intensive care units. Although sepsis-associated encephalopathy (SAE) is reported to be a leading manifestation of sepsis, its pathogenesis remains to be elucidated. In this study, we investigated whether exogenous recombinant human erythropoietin (rhEPO) could protect brain from neuronal apoptosis in the model of SAE. We showed that application of rhEPO enhanced Bcl-2, decreased Bad in lipopolysaccharide treated neuronal cultures, and improved neuronal apoptosis in hippocampus of cecal ligation and peroration rats. We also found that rhEPO increased the expression of phosphorylated AKT, and the antiapoptotic role of rhEPO could be abolished by phosphoinositide 3-kinase (PI3K)/AKT inhibitor LY294002 or SH-5. In addition, systemic sepsis inhibited the hippocampal-phosphorylated mammalian target of rapamycin (mTOR) and p70S6K (downstream substrates of PKB/AKT signaling), which were restored by administration of exogenous rhEPO. Moreover, treatment with mTOR-signaling inhibitor rapamycin or transfection of mTOR siRNA reversed the neuronal protective effects of rhEPO. Finally, exogenous rhEPO rescued the emotional and spatial cognitive defects without any influence on locomotive activity. These results illustrated that exogenous rhEPO improves brain dysfunction by reducing neuronal apoptosis, and AKT/mTOR signaling is likely to be involved in this process. Application of rhEPO may serve as a potential therapy for the treatment of SAE.

Recent advances toward defining the benefits and risks of erythrocyte transfusions in neonates

Like many treatments available to small or ill neonates, erythrocyte transfusions carry both benefits and risks. This review examines recent publications aimed at better defining those benefits and those risks, as means of advancing evidence-based neonatal intensive care unit transfusion practices. Since decisions regarding whether to not to order an erythrocyte transfusion are based, in part, on the neonate's blood haemoglobin concentration, the authors also review recent studies aimed at preventing the haemoglobin from falling to a point where a transfusion is considered.

A randomized, masked, placebo-controlled study of darbepoetin alfa in preterm infants

BACKGROUND

A novel erythropoiesis stimulating agent (ESA), darbepoetin alfa (Darbe), increases hematocrit in anemic adults when administered every 1 to 3 weeks. Weekly Darbe dosing has not been evaluated in preterm infants. We hypothesized that infants would respond to Darbe by decreasing transfusion needs compared with placebo, with less-frequent dosing than erythropoietin (Epo).

METHODS

Preterm infants 500 to 1250 g birth weight and ≤48 hours of age were randomized to Darbe (10 μg/kg, 1 time per week subcutaneously), Epo (400 U/kg, 3 times per week subcutaneously) or placebo (sham dosing) through 35 weeks' gestation. All received supplemental iron, folate, and vitamin E, and were transfused according to protocol. Transfusions (primary outcome), complete blood counts, absolute reticulocyte counts (ARCs), phlebotomy losses, and adverse events were recorded.

RESULTS

A total of 102 infants (946 ± 196 g, 27.7 ± 1.8 weeks' gestation, 51 ± 25 hours of age at first dose) were enrolled. Infants in the Darbe and Epo groups received significantly fewer transfusions (P = .015) and were exposed to fewer donors (P = .044) than the placebo group (Darbe: 1.2 ± 2.4 transfusions and 0.7 ± 1.2 donors per infant; Epo: 1.2 ± 1.6 transfusions and 0.8 ± 1.0 donors per infant; placebo: 2.4 ± 2.9 transfusions and 1.2 ± 1.3 donors per infant). Hematocrit and ARC were higher in the Darbe and Epo groups compared with placebo (P = .001, Darbe and Epo versus placebo for both hematocrit and ARCs). Morbidities were similar among groups, including the incidence of retinopathy of prematurity.

CONCLUSIONS

Infants receiving Darbe or Epo received fewer transfusions and fewer donor exposures, and fewer injections were given to Darbe recipients. Darbepoetin and Epo successfully serve as adjuncts to transfusions in maintaining red cell mass in preterm infants.

Neonatal brain protection in cardiac surgery and the role of intraoperative neuromonitoring

Improving mortality rates in children undergoing surgery for congenital heart disease has enabled a shift in focus to improving morbidity, particularly with respect to neurological complications. Various factors have been implicated in influencing neurological outcomes. We share our experience in formulating a customized cardiopulmonary bypass (CPB) protocol based on currently available evidence. Theoretical advantages of intraoperative neuromonitoring during CPB, specifically use of near-infrared spectroscopy, will be discussed in the context of methodologies to monitor cerebral perfusion during surgery.

Otoprotective effect of recombinant erythropoietin in a model of newborn hypoxic-ischemic encephalopathy

OBJECTIVE

The aim of this study is to test the hypotheses that central auditory pathology as well as inner ear pathology is contributing mechanisms to observed hypoxic-ischemic encephalopathy (HIE) induced hearing loss and that recombinant erythropoietin (rhEPO) will reduce this cellular pathology and attenuate hearing loss.

METHODS

Twenty-eight 7-day Wistar albino rat pups were divided into four groups: Control group (n=8) was given only intraperitoneal saline solution. Sham group (n=5) had only a midline neck incisions without carotid ligation under general anesthesia and administration of intraperitoneal saline solution. HIE group (n=8) and rhEPO treated group (n=7) were subjected to left common carotid artery ligation followed by 2.5h hypoxia exposure to a mixture of 8% oxygen and 92% pure nitrogen. HIE group was injected with intraperitoneal saline solution, while the rhEPO treated group received rhEPO 100 U/kg within the same volume as the saline-alone solution. At the end of the seventh week of age hearing (ABRs) was evaluated in response to clicks, 6 kHz and 8 kHz tone burst stimuli. Animals were sacrificed and both temporal lobes, cochleas and brainstems of the animals were collected. Tissue samples were evaluated with light microscopy, immunohistochemical studies, including TUNEL and caspase-3 stainings, and electron microscopy.

RESULTS

Hearing thresholds were elevated in HIE animals. In rhEPO treated animals, ABR values were similar to controls. HIE caused apoptotic changes in brainstem structures as shown by light microscopy and immunohistochemical methods. Apoptotic changes also were found within the organ of Corti, spiral ganglion cells and neurons of temporal lobe by electron microscopic investigation. In rhEPO animals many of these apoptotic changes were observed, but reduced compared to untreated animals.

CONCLUSIONS

Mechanisms underlying HIE-induced hearing loss are based on apoptosis in inner ear; however central auditory pathway pathology occurs as well, likely contributing to changes in auditory processing and perception of complex signals not reflected by the ABR threshold shifts. For both clinical and basic significance 'rhRPO' is found to reduce those effects.

Outcomes of extremely low birth weight infants given early high-dose erythropoietin

OBJECTIVE

To evaluate long-term outcomes of 60 extremely low birth weight (ELBW) infants treated with or without three injections of high-dose erythropoietin (Epo).

STUDY DESIGN

A retrospective analysis of anthropometric and neurodevelopmental outcome data comparing 30 ELBW infants enrolled in a phase I/II study examining the pharmacokinetics of high-dose Epo (500, 1000 and 2500 U/kg × 3 doses) administered to 30 concurrent controls.

RESULT

Birth characteristics and growth from 4 to 36 months were similar for untreated and Epo-treated patients. Multiple linear regression analysis of neurodevelopmental follow-up scores from 17/25 Epo-treated and 18/26 control infants identified that Epo correlated with improvement of cognitive (R=0.22, P=0.044) and motor (R=0.15, P=0.026) scores. No negative long-term effects of Epo treatment were evident.

CONCLUSION

Retrospective analysis of the only available long-term follow-up data from ELBW infants given high-dose Epo treatment suggests that Epo treatment is safe and correlates with modest improvement of neurodevelopmental outcomes.

Erythropoietin as a neuroprotectant for neonatal brain injury: animal models

Prematurity and perinatal hypoxia-ischemia are common problems that result in significant neurodevelopmental morbidity and high mortality worldwide. The Vannucci model of unilateral brain injury was developed to model perinatal brain injury due to hypoxia-ischemia. Because the rodent brain is altricial, i.e., it develops postnatally, investigators can model either preterm or term brain injury by varying the age at which injury is induced. This model has allowed investigators to better understand developmental changes that occur in susceptibility of the brain to injury, evolution of brain injury over time, and response to potential neuroprotective treatments. The Vannucci model combines unilateral common carotid artery ligation with a hypoxic insult. This produces injury of the cerebral cortex, basal ganglia, hippocampus, and periventricular white matter ipsilateral to the ligated artery. Varying degrees of injury can be obtained by varying the depth and duration of the hypoxic insult. This chapter details one approach to the Vannucci model and also reviews the neuroprotective effects of erythropoietin (Epo), a neuroprotective treatment that has been extensively investigated using this model and others.

A randomized, masked study of weekly erythropoietin dosing in preterm infants

OBJECTIVE

To compare reticulocyte responses of once-per-week erythropoietin (EPO) dosing with 3-times-a-week dosing in preterm infants.

STUDY DESIGN

Infants weighing ≤ 1500 g and ≥ 7 days of age were randomized to once-per-week EPO, 1200 U/kg/dose, or 3-times-a-week EPO, 400 U/kg/dose, subcutaneously for 4 weeks, along with iron and vitamin supplementation. Complete blood counts, absolute reticulocyte counts (ARCs), transfusions, phlebotomy losses, and adverse events were recorded.

RESULTS

Twenty preterm infants (962 ± 55 g, 27.9 ± 0.4 weeks, 17 ± 3 days of age) were enrolled. Groups were similar at baseline. Infants in both groups had increased ARCs, which were similar between treatment groups at the start and end of 4 weeks. Hematocrit remained stable, and similar numbers of transfusions were administered. No adverse effects of either dosing schedule were noted.

CONCLUSIONS

Preterm infants respond to weekly EPO by increasing ARCs and maintaining hematocrit. We speculate that once-per-week EPO dosing might be beneficial to preterm infants requiring increased erythropoiesis.

Hematological interventions in NICU care: the use of rEpo, IVIG, and rG-CSF

This article focuses on the use of rEpo, IVIG, and rG-CSF in the NICU. It discusses the most recent studies and the most definitive and clinically relevant evidence, rather than summarizing all published studies. The last section was written for NICU practice groups that choose to use any of these medications and are seeking a consistent approach for doing so. The section provides the author's approach to the use of rEpo, IVIG, and rG-CSF, revealing personal preferences, interpretations, and experiences, and is based on the dictum, "if you are going to use it, use it the same way each time."

Hypoxic ischemic encephalopathy--what can we learn from humans?

Hypoxic ischemic encephalopathy (HIE) is a condition that occurs in both human newborns and foals. The condition is the subject of extensive current research in human infants, but there have been no direct studies of HIE in foals, and hence, knowledge of the condition has been extrapolated from studies in humans and other animal models. The purpose of this review article is to highlight the most up-to-date and relevant research in the human field, and discuss how this potentially might have an impact in the management of foals with HIE.

Erythropoietin in neonatal brain protection: the past, the present and the future

Over the last decade, neuroprotective effects of erythropoietin (Epo) and its underlying mechanisms in terms of signal transduction pathways have been defined and there is a growing interest in the potential therapeutic use of Epo for neuroprotection. Several mechanisms by which Epo provides neuroprotection are recognized. In this review, we focused on the neuroprotective mechanisms of Epo and provide a short overview on both experimental and clinical studies, testing Epo as a neuroprotective agent in the neonatal brain injury, and the safety concerns with the clinical use of Epo treatment in neonates.

Erythropoietin reduces neuronal cell death and hyperalgesia induced by peripheral inflammatory pain in neonatal rats

Painful stimuli during neonatal stage may affect brain development and contribute to abnormal behaviors in adulthood. Very few specific therapies are available for this developmental disorder. A better understanding of the mechanisms and consequences of painful stimuli during the neonatal period is essential for the development of effective therapies. In this study, we examined brain reactions in a neonatal rat model of peripheral inflammatory pain. We focused on the inflammatory insult-induced brain responses and delayed changes in behavior and pain sensation. Postnatal day 3 pups received formalin injections into the paws once a day for 3 days. The insult induced dysregulation of several inflammatory factors in the brain and caused selective neuronal cell death in the cortex, hippocampus and hypothalamus. On postnatal day 21, rats that received the inflammatory nociceptive insult exhibited increased local cerebral blood flow in the somatosensory cortex, hyperalgesia, and decreased exploratory behaviors. Based on these observations, we tested recombinant human erythropoietin (rhEPO) as a potential treatment to prevent the inflammatory pain-induced changes. rhEPO treatment (5,000 U/kg/day, i.p.), coupled to formalin injections, ameliorated neuronal cell death and normalized the inflammatory response. Rats that received formalin plus rhEPO exhibited normal levels of cerebral blood flow, pain sensitivity and exploratory behavior. Treatment with rhEPO also restored normal brain and body weights that were reduced in the formalin group. These data suggest that severe inflammatory pain has adverse effects on brain development and rhEPO may be a possible therapy for the prevention and treatment of this developmental disorder.

Glutamate signaling in the pathophysiology and therapy of prenatal insults

Birth asphyxia and hypoxia-ischemia (HI) are important factors affecting the normal development and maturation of the central nervous system (CNS). Depending on the maturity of the brain, HI-induced damage at different ages is region-selective, the white matter (WM) peripheral to the lateral ventricles being selectively vulnerable to damage in premature infants. As a squeal of primary or secondary HI in the preterm infant, the brain injury comprises periventricular leukomalasia (PVL), accompanied by neuronal and axonal damage, which affects several brain regions. Premature delivery and improved neonatal intensive care have led to a survival rate of about 75% to 90% of infants weighting under 1500g both in Europe and in the United States. However, about 5-10% of these survivors exhibit cerebral palsy (CP), and many have cognitive, behavioral, attentional or socialization deficits. In this review, we first shortly discuss developmental changes in the expression of the excitatory glutamate receptors (GluRs), and then in more detail elucidate the contribution of GluRs to oligodendrocyte (OL) damage both in experimental models and in preterm human infants. Finally, therapeutic interventions targeted at GluRs at the young age are discussed in the light of results obtained from recent experimental HI animal models and from humans.

Care for child development: basic science rationale and effects of interventions

The past few years have witnessed increasing interest in devising programs to enhance early childhood development. We review current understandings of brain development, recent advances in this field, and their implications for clinical interventions. An expanding body of basic science laboratory data demonstrates that several interventions, including environmental enrichment, level of parental interaction, erythropoietin, antidepressants, transcranial magnetic stimulation, transcranial direct current stimulation, hypothermia, nutritional supplements, and stem cells, can enhance cerebral plasticity. Emerging clinical data, using functional magnetic resonance imaging and clinical evaluations, also support the hypothesis that clinical interventions can increase the developmental potential of children, rather than merely allowing the child to achieve an already predetermined potential. Such interventions include early developmental enrichment programs, which have improved cognitive function; high-energy and high-protein diets, which have increased brain growth in infants with perinatal brain damage; constraint-induced movement therapy, which has improved motor function in patients with stroke, cerebral palsy, and cerebral hemispherectomy; and transcranial magnetic stimulation, which has improved motor function in stroke patients.

[Early administration of erythropoietin in the extreme premature, a risk factor for retinopathy of prematurity?]

INTRODUCTION

Erythropoietin (EPO) stimulates angiogenesis and may favour the appearance of retinopathy of prematurity (ROP). The objective was to determine if EPO+Fe administered from the 5th day of life could be an independent risk factor for ROP appearance and its severity.

PATIENTS AND METHOD

The study included 718 preterm newborns with a birth weight ≤1,500g or a gestational age ≤32 weeks (and 6 days), admitted between 2001 and 2008. During these years, the target SaO₂ was between 88% and 93%. EPO treatment began at 5-7 days of life, with a dose of 250 UI/Kg, 3 times a week, subcutaneously, together with Fe, 5-6mg/kg/day, both until 34 weeks of corrected age or discharge.

RESULTS

A total of 493 preterms (68.7%) did not have ROP, 139 (19.4%) had a grade 1 ROP, 50 (7.0%) a grade 2 ROP and 36 (5.0%) a grade 3 ROP. Laser therapy was required by 27 severe ROP was associated with lower birth weight and gestational age, more neonatal morbidity and a more aggressive treatment (duration of oxygen supplements or mechanical ventilation, number of blood transfusions). Risk factors independently and significantly associated with any ROP grade were: lower birth weight, no caesarean section, EPO administration and need for blood transfusion. EPO administration increased the risk of ROP by 2.4, but this only happened in case of grade 1 ROP (OR: 5.50).

CONCLUSIONS

EPO+Fe administration is associated and perhaps stimulates the appearance of grade 1 ROP.

Postnatal erythropoietin treatment mitigates neural cell loss after systemic prenatal hypoxic-ischemic injury

OBJECT

Brain injury from preterm birth predisposes children to cerebral palsy, epilepsy, cognitive delay, and behavioral abnormalities. The CNS injury often begins before the early birth, which hinders diagnosis and concurrent treatment. Safe, effective postnatal interventions are urgently needed to minimize these chronic neurological deficits. Erythropoietin (EPO) is a pleiotropic neuroprotective cytokine, but the biological basis of its efficacy in the damaged developing brain remains unclear. Coordinated expression of EPO ligand and receptor expression occurs during CNS development to promote neural cell survival. The authors propose that prenatal third trimester global hypoxia-ischemia disrupts the developmentally regulated expression of neural cell EPO signaling, and predisposes neural cells to death. Furthermore, the authors suggest that neonatal exogenous recombinant human EPO (rhEPO) administration can restore the mismatch of EPO ligand and receptor levels, and enhance neural cell survival.

METHODS

Transient systemic hypoxia-ischemia (TSHI) on embryonic Day 18 in rats mimics human early-third trimester placental insufficiency. This model was used to test the authors' hypothesis using a novel clinically relevant paradigm of prenatal injury on embryonic Day 18, neonatal systemic rhEPO administration initiated 4 days after injury on postnatal Day 1, and histological, biochemical, and functional analyses in neonatal, juvenile, and adult rats.

RESULTS

The results showed that prenatal TSHI upregulates brain EPO receptors, but not EPO ligand. Sustained EPO receptor upregulation was pronounced on oligodendroglial lineage cells and neurons, neural cell populations particularly prone to loss from CNS injury due to preterm birth. Postnatal rhEPO administration after prenatal TSHI minimized histological damage and rescued oligodendrocytes and gamma-aminobutyric acidergic interneurons. Myelin basic protein expression in adult rats after insult was reduced compared with sham controls, but could be restored to near normal levels by neonatal rhEPO treatment. Erythropoietin-treated TSHI rats performed significantly better than their saline-treated peers as adults in motor skills tests, and showed significant seizure threshold restoration using a pentylenetetrazole increasing-dose paradigm.

CONCLUSIONS

These data demonstrate that neonatal rhEPO administration in a novel clinically relevant paradigm initiated 4 days after a global prenatal hypoxic-ischemic insult in rats rescues neural cells, and induces lasting histological and functional improvement in adult rats.

Absence of hematological side effects in acute and subacute nasal dosing of erythropoietin with a low content of sialic acid

The use of human recombinant erythropoietin (EPO) as a neuroprotective agent is limited due to its hematological side effects. An erythropoietin along with a low content of sialic acid (rhEPOb), similar to that produced in the brain during hypoxia, may be used as a neuroprotective agent without risk of thrombotic events. The objective of this investigation was to assess the toxicological potential of a nasal formulation with rhEPOb in acute, subacute and nasal irritation assays in rats. Healthy Wistar rats (Cenp:Wistar) were used for the assays. In an irritation test, animals received 15 μl of rhEPOb into the right nostril. Rats were sacrificed after 24 h and slides of the nasal mucosa tissues were examined. Control and treated groups showed signs of a minimal irritation consisting of week edema and vascular congestion in all animals. In the acute toxicity test, the dose of 47,143 UI/kg was administered by nasal route. Hematological patterns, body weight, relative organ weight, and organ integrity were not affected by single dosing with rhEPOb. In the subacute toxicity test, Wistar rats of both sexes received 6,600 UI/kg/day for 14 days. The toxicological endpoints examined included animal body weight, food consumption, hematological and biochemical patterns, selected tissue weights, and histopathological examinations. An increase of lymphocytes was observed in males that was considered to reflect an immune response to treatment. Histopathological examination of organs and tissues did not reveal treatment-induced changes. The administration of rhEPOb at daily doses of 6,600 UI/kg during 14 days did not produce hematological side effects. These results suggest that rhEPOb could offer the same neuroprotection as EPO, without hematological side effects.