Long-term treatment with transcranial pulsed electromagnetic fields improves movement speed and elevates cerebrospinal erythropoietin in Parkinson's disease.

BACKGROUND: Parkinson's disease is characterized by motor dysfunctions including bradykinesia. In a recent study, eight weeks of daily transcranial stimulation with bipolar pulsed electromagnetic fields improved functional rate of force development and decreased inter-hand tremor coherence in patients with mild Parkinson's disease. OBJECTIVE: To investigate the effect of long-term treatment with transcranial bipolar pulsed electromagnetic fields on motor performance in terms of movement speed and on neurotrophic and angiogenic factors. METHODS: Patients diagnosed with idiopathic Parkinson's disease had either daily 30-min treatment with bipolar (±50 V) transcranial pulsed electromagnetic stimulation (squared pulses, 3ms duration) for three eight-week periods separated by one-week pauses (T-PEMF group) (n = 16) or were included in a PD-control group (n = 8). Movement speed was assessed in a six-cycle sit-to-stand task performed on a force plate. Cerebrospinal fluid and venous blood were collected and analyzed for erythropoietin and vascular endothelial growth factor. RESULTS: Major significant improvement of movement speed compared to the natural development of the disease was found (p = 0.001). Thus, task completion time decreased gradually during the treatment period from 10.10s to 8.23s (p<0.001). The untreated PD-control group did not change (p = 0.458). The treated group did not differ statistically from that of a healthy age matched reference group at completion of treatment. Erythropoietin concentration in the cerebrospinal fluid also increased significantly in the treated group (p = 0.012). CONCLUSION: Long-term treatment with transcranial bipolar pulsed electromagnetic fields increased movement speed markedly and elevated erythropoietin levels. We hypothesize that treatment with transcranial bipolar pulsed electromagnetic fields improved functional performance by increasing dopamine levels in the brain, possibly through erythropoietin induced neural repair and/or protection of dopaminergic neurons.

Cerebrospinal fluid neuron specific enolase, interleukin-1ß and erythropoietin concentrations in children after seizures.

PURPOSE: In the present study, the levels of neuron-specific enolase (NSE), interleukin-1ß (IL-1ß), and erythropoietin (EPO) in cerebrospinal fluid (CSF) in children with idiopathic epilepsy were measured to illuminate the relationships between these markers with idiopathic epilepsy. METHODS: Eighty-five children from 6 months to 12.5 years of age with single, previously undiagnosed, and untreated idiopathic epilepsy were participated in this study. The concentrations of CSF NSE, 1L-1ß, and EPO were measured by specific ELISA methods. RESULTS: The mean concentrations of CSF NSE, IL-1ß, and EPO in the epileptic groups showed a significant increase (P < 0.01) compared with those in the control groups. Besides, the mutual correlations of NSE, 1L-1ß, and EPO were also analyzed. Results showed that there were positive correlations between the levels of IL-1ß, NSE, and EPO. CONCLUSIONS: The changes of NSE, 1L-1ß, and EPO level in CSF may be beneficial for the pathophysiology study of epileptic seizures and the identification and diagnosis of a seizure clinically.

Perinatal Asphyxia and Erythropoietin and VEGF: Serial Serum and Cerebrospinal Fluid Responses.

BACKGROUND: Infants with neonatal encephalopathy (NE) of hypoxic-ischaemic origin are at risk of oxidative and ischaemia-reperfusion injury, which may induce abnormal inflammatory responses involving excessive cytokine production and release in serum and cerebrospinal fluid (CSF). Systemic inflammation is found in infants with NE, and we therefore were interested in cytokines associated with hypoxia, including vascular endothelial growth factor (VEGF) and erythropoietin (Epo). OBJECTIVE: To investigate the relationship between Epo, VEGF levels, brain injury and outcome in a group of term infants exposed to perinatal asphyxia (PA) compared to controls. METHODS: Serum and CSF biomarkers associated with hypoxia (VEGF, Epo) were serially measured using multiplex immunoassays over days 1-4 in term infants exposed to PA including infants with NE and controls. Results were compared to severity of encephalopathy, MR brain imaging and mortality. RESULTS: Ninety-four infants had 247 serum samples collected (n = 12 controls, 82 exposed to PA with 34 CSF samples), and 4 infants died. Controls had significantly lower serum Epo levels on days 1 and 2 compared to those exposed to PA (p = 0.02). Grade II/III NE was significantly associated with elevated day 2 Epo and decreased day 1 VEGF (p < 0.05; day 2 Epo AUC = 0.74, cut-off 10.05 IU/ml). Elevated serum Epo was associated with severely abnormal MRI. Mortality was associated with elevated day 3 Epo and decreased day 1 VEGF. CSF levels were all after hypothermia and were not significantly associated with outcome. CONCLUSION: Serum Epo and VEGF may be markers of severity of hypoxia-ischaemia and brain injury as they are closely related to hypoxic exposure.

High plasma erythropoietin levels are associated with prolonged coma duration and increased mortality in children with cerebral malaria.

BACKGROUND: Elevated endogenous plasma erythropoietin (EPO) levels have been associated with protection from acute neurologic deficits in Kenyan children with cerebral malaria (CM). Based on these findings and animal studies, clinical trials of recombinant human EPO (rHuEPO) have been started in children with CM. Recent clinical trials in adults with acute ischemic stroke have demonstrated increased mortality with rHuEPO treatment. We conducted a study in children with CM to assess the relationship of endogenous plasma and cerebrospinal fluid (CSF) EPO levels with mortality and acute and long-term neurologic outcomes. METHODS: A total of 210 children between 18 months and 12 years of age with a diagnosis of CM, were enrolled at Mulago Hospital, Kampala, Uganda. Plasma (n = 204) and CSF (n = 147) EPO levels at admission were measured by radioimmunoassay and compared with mortality and neurologic outcomes. RESULTS: After adjustment for age and hemoglobin level, a 1-natural-log increase in plasma EPO level was associated with a 1.74-fold increase in mortality (95% confidence interval, 1.09-2.77, P = .02). Plasma and CSF EPO levels also correlated positively with coma duration (P = .05 and P = .02, respectively). Plasma and CSF EPO levels did not differ in children with vs those without acute or long-term neurologic deficits. Plasma EPO levels correlated positively with markers of endothelial and platelet activation and histidine-rich protein-2 levels, but remained associated with mortality after adjustment for these factors. CONCLUSIONS: High endogenous plasma EPO levels are associated with prolonged coma duration and increased mortality in children >18 months of age with CM.

High performance collection of cerebrospinal fluid in rats: evaluation of erythropoietin penetration after osmotic opening of the blood-brain barrier.

An important issue to be considered when studying a new drug for treatment of central nervous system (CNS) diseases is its ability to cross the blood-brain barrier (BBB) and distribute throughout the brain. As cerebrospinal fluid (CSF) has demonstrated to be an invaluable reservoir to study CNS availability of therapeutic proteins, we have developed an improved method for CSF sampling from the cisterna magna of rats. The technique enables the simple and rapid collection of adequate quantities (50-75 µl) of blood-free CSF, rendering a high percentage of animal survival (99%) without clinic or neurological consequences. Its success in avoiding blood contamination of CSF lays in the use of a mixture of lidocaine/ephinephrine topically injected in the rat's suboccipital area and neck. Another relevant feature of the methodology is its low cost, since the puncture device can be easily assembled with cheap and available materials and, more importantly, neither expensive stereotaxic equipment nor frame is required. The present method is demonstrated by studying the CSF pharmacokinetics of recombinant human erythropoietin (rhEPO), a well-studied therapeutic candidate for neurological diseases. Moreover, we applied this technique to evaluate a strategy of osmotic disruption of the BBB to achieve a faster delivery of rhEPO into the CNS.

Brain and skin do not contribute to the systemic rise in erythropoietin during acute hypoxia in humans.

Erythropoietin (EPO) preserves arterial oxygen content by controlling red blood cell and plasma volumes. Synthesis of EPO was long thought to relate inversely to renal oxygenation, but in knockout mice, brain and skin have been identified as essential for the acute hypoxic EPO response. Whether these findings apply to humans remains unknown. We exposed healthy young subjects to hypoxia (equivalent to 3800 m) and measured EPO in arterial and jugular venous plasma and in cerebrospinal fluid. To examine the role of the skin for EPO production during hypoxia, subjects were exposed to 8 h of hypobaric hypoxia with or without breathing oxygen-enriched air to ensure systemic normoxemia. With 9 h of hypoxia, arterial EPO increased (from 6.0±2.2 to 22.0±6.0 mU/ml, n=11, P<0.0001) and jugular venous EPO displayed a similar response (to 22.2±6.0 mU/ml, n=11). Thus, the arterio-jugular venous EPO difference was unaffected by hypoxia and also in cerebrospinal fluid EPO remained stable following hypoxic exposure (0.33±0.15 mU/ml, n=9 in normoxia vs. 0.41±0.20 mU/ml, n=9 in hypoxia, P=0.40). No change in plasma EPO was observed when only skin was exposed to hypobaric hypoxia (n=8). Thus, neither dermal oxygen exposure nor cerebral EPO production appears to be important for the systemic EPO response to acute hypoxia in healthy humans.

Rapid affinity purification of erythropoietin from biological samples using disposable monoliths.

Identification of post-translational modifications of proteins in biological samples often requires access to preanalytical purification and concentration methods. In the purification step high or low molecular weight substances can be removed by size exclusion filters, and high abundant proteins can be removed, or low abundant proteins can be enriched, by specific capturing tools. In this paper is described the experience and results obtained with a recently emerged and easy-to-use affinity purification kit for enrichment of the low amounts of EPO found in urine and plasma specimens. The kit can be used as a pre-step in the EPO doping control procedure, as an alternative to the commonly used ultrafiltration, for detecting aberrantly glycosylated isoforms. The commercially available affinity purification kit contains small disposable anti-EPO monolith columns (6 µL volume, Ø7 mm, length 0.15 mm) together with all required buffers. A 24-channel vacuum manifold was used for simultaneous processing of samples. The column concentrated EPO from 20 mL urine down to 55 µL eluate with a concentration factor of 240 times, while roughly 99.7% of non-relevant urine proteins were removed. The recoveries of Neorecormon (epoetin beta), and the EPO analogues Aranesp and Mircera applied to buffer were high, 76%, 67% and 57%, respectively. The recovery of endogenous EPO from human urine was 65%. High recoveries were also obtained when purifying human, mouse and equine EPO from serum, and human EPO from cerebrospinal fluid. Evaluation with the accredited EPO doping control method based on isoelectric focusing (IEF) showed that the affinity purification procedure did not change the isoform distribution for rhEPO, Aranesp, Mircera or endogenous EPO. The kit should be particularly useful for applications in which it is essential to avoid carry-over effects, a problem commonly encountered with conventional particle-based affinity columns. The encouraging results with EPO propose that similar affinity monoliths, with the appropriate antibodies, should constitute useful tools for general applications in sample preparation, not only for doping control of EPO and other hormones such as growth hormone and insulin but also for the study of post-translational modifications of other low abundance proteins in biological and clinical research, and for sample preparation prior to in vitro diagnostics.

Effects of erythropoietin administration on cerebral metabolism and exercise capacity in men.

Recombinant human erythropoietin (EPO) increases exercise capacity by stimulating erythropoiesis and subsequently enhancing oxygen delivery to the working muscles. In a large dose, EPO crosses the BBB and may reduce central fatigue and improve cognition. In turn, this would augment exercise capacity independent of erythropoiesis. To test this hypothesis, 15 healthy young men (18-34 years old, 74 + or - 7 kg) received either 3 days of high-dose (30,000 IU/day; n = 7) double-blinded placebo controlled or 3 mo of low-dose (5,000 IU/wk; n = 8) counter-balanced open but controlled administration of EPO. We recorded exercise capacity, transcranial ultrasonography-derived middle cerebral artery blood velocity, and arterial-internal jugular venous concentration differences of glucose and lactate. In addition, cognitive function, ratings of perceived exertion, ventilation, and voluntary activation by transcranial magnetic stimulation-induced twitch force were evaluated. Although EPO in a high dose increased cerebrospinal fluid EPO concentration approximately 20-fold and affected ventilation and cerebral glucose and lactate metabolism (P < 0.05), 3 days of high-dose EPO administration had no effect on cognition, voluntary activation, or exercise capacity, but ratings of perceived exertion increased (P < 0.05). We confirmed that 3 mo of administration of EPO increases exercise capacity, but the improvement could not be accounted for by other mechanisms than enhanced oxygen delivery. In conclusion, EPO does not attenuate central fatigue or change cognitive performance strategy, suggesting that EPO enhances exercise capacity exclusively by increased oxygen delivery to the working muscles.

High cerebrospinal fluid antioxidants and interleukin 8 are protective of hypoxic brain damage in newborns.

The objective was to explain the discrepancy in the development of hypoxic ischemic brain injury (HIE) in some asphyxiated newborns rather than others. Forty newborns were classified according to their cerebrospinal neuron-specific-enolase (CSF-NSE) levels on their 5th-day of life; group 1 with low-NSE (n = 25). The remaining 15 newborns had high-NSE and were further divided into a group with no HIE (n = 10, group 2) and another with HIE (n = 5, group 3). CSF-NSE, total-hydroperoxide (TH), biological-antioxidant-potentials (BAPs), 12 cytokines and erythropoietin (EPO) were measured. The TH/BAP gave the oxidative-stress-index (OSI). The BAPs of serial dilutions of three types of EPO were tested. CSF-NSE and TH and mean OSIs were higher in group 3. IL-8 and mean BAPs were higher in group 2 than in group 1. EPO was less detected in group 3. Serial EPO dilutions correlated with their BAPs. Compensatory antioxidants and IL-8 elevation could be protective of perinatal asphyxic brain injury. Antioxidative effect of EPO could be neuroprotective.

Erythropoietin concentration in serum and cerebrospinal fluid of patients with amyotrophic lateral sclerosis.

Erythropoietin (EPO) acts as a neuroprotective factor and is upregulated after neuronal injury. It has been reported that in cerebrospinal fluid (CSF) of amyotrophic lateral sclerosis (ALS) patients, the EPO concentration is decreased. In this study, EPO levels in serum and CSF of 30 patients with ALS and in 15 controls, using an ELISA technique, were estimated. EPO level in serum was decreased, especially in patients with bulbar onset ALS. A trend toward a progressive EPO decline with the duration of the disease in the mild + moderate ALS cases was observed. In severe cases, a tendency towards a positive correlation of EPO and duration of the disease was present. Serum EPO values were age related only in mild + moderate ALS in patients below 40 years of age. In CSF, the EPO levels were significantly decreased. Lower EPO values in the bulbar onset ALS when compared with the spinal onset ALS were present. The EPO decrease did not correlate with the severity and duration of the disease. Age relation of the EPO level only in the mild + moderate ALS cases more than 40 years was present. Lack of differences in EPO levels between patients with ALS of rapid and slow progression indicates that EPO concentration cannot be used as a prognostic factor. Nevertheless, the decreased serum and CSF EPO concentration and the known EPO neuroprotective action may indicate that EPO administration can be a new promising therapeutic approach in ALS.

CSF profiles of angiogenic and inflammatory factors depend on the respiratory status of ALS patients.

Our objective was to assess the regulation of the hypoxia response of angiogenic and inflammatory factors from 76 cerebrospinal fluids (CSF) of sporadic amyotrophic lateral sclerosis (ALS) patients with different respiratory status. We first analysed the hypoxia response capacity by measuring CSF levels of angiogenin (ANG), VEGF, angiopoietin-2 (ANG-2) and PGE-2 in 40 ALS patients according to their hypoxaemia level and compared it with 40 neurological controls. We then compared the ANG, VEGF, EPO and ANG-2 CSF levels of 36 other ALS patients, divided into three groups with either 1) normoxaemia, 2) intermittent desaturation in the absence of hypoxaemia, or 3) chronic hypoxaemia with or without desaturation. We demonstrated a lack of up-regulation of both ANG and VEGF during hypoxaemia in ALS, compared with hypoxaemic controls. In contrast, PGE-2 and ANG-2 levels were increased in both hypoxaemic ALS patients and controls. ANG and VEGF levels did not increase in patients with long disease durations and with intermittent or chronic hypoxaemia. ANG-2 and EPO levels were up-regulated early in intermittent hypoxaemia and late in chronic hypoxaemia, respectively. Our results suggest alteration of the HIF-1alpha-mediated response to hypoxia during sporadic ALS, whereas the NFK-B pathway seems early activated.

No neuroprotective effect of erythropoietin under clinical treatment conditions in a rabbit model of Escherichia coli meningitis.

Despite effective antibiotic treatment, neuronal injury is frequent among children and adults with bacterial meningitis resulting in a high rate of death and neurologic sequelae. The hematopoietic cytokine erythropoietin (EPO) provides neuroprotection in models of acute and chronic neurologic diseases. We studied whether recombinant EPO (rEPO) reduces neuronal damage in a rabbit model of Escherichia coli meningitis. Inflammation within the central nervous system (CNS) was monitored by measurement of bacterial load, pleocytosis, protein, and lactate in the cerebrospinal fluid (CSF). Neuronal damage was measured by quantification of the density of apoptotic neurons in the hippocampal dentate gyrus and the concentration of the global neuronal destruction marker neuron-specific enolase (NSE) in CSF. To increase clinical relevance, rEPO was applied as adjunctive therapy from the beginning of antibiotic therapy 12 h after infection. EPO treatment applied as an intravenous injection at a dose of 1000 IU/kg body weight resulted in plasma concentrations of 6993 +/- 1406 mIU/mL, CSF concentrations of 1291 +/- 568 mIU/mL, and a CSF-to-plasma ratio of 0.18 +/- 0.07 (mean +/- SD) 6 h after injection. Under these treatment conditions, no anti-inflammatory or neuroprotective effect of EPO was observed. "

Erythropoietin in patients with aneurysmal subarachnoid haemorrhage: a double blind randomised clinical trial.

BACKGROUND: Erythropoietin (EPO) is neuroprotective in experimental models of stroke and subarachnoid haemorrhage (SAH) and possibly in patients with thromboembolic stroke. We studied the efficacy and safety of EPO in patients with SAH. METHODS: A larger scale clinical trial was planned but preliminarily terminated because of a lower than expected inclusion rate. However, 73 patients were randomised to treatment with EPO (500 IU/kg/day for three days) or placebo. The primary endpoint was Glasgow Outcome Score at six months. We further studied surrogate measures of secondary ischaemia, i.e. transcranial Doppler (TCD) flow velocity, symptomatic vasospasm, cerebral metabolism (microdialysis) and jugular venous oximetry, biochemical markers of brain damage (S-100beta and neuron specific enolase) and blood-brain barrier integrity. FINDINGS: The limited sample size precluded our primary hypotheses being verified and refuted. However, data from this study are important for any other study of SAH and as much raw data as possible are presented and can be included in future meta analyses. On admission the proportion of patients in a poor condition was higher in the EPO group compared with the placebo group but the difference was statistically insignificant. In the EPO-treated patients the CSF concentration of EPO increased 600-fold. Except for a higher extracelullar concentration of glycerol in the EPO group probably caused by the poorer clinical condition of these patients, there were no statistically significant group differences in the primary or secondary outcome measures. EPO was well tolerated. CONCLUSIONS: Beneficial effects of EPO in patients with SAH cannot be excluded or concluded on the basis of this study and larger scale trials are warranted.

Erythropoietin in cerebrospinal fluid: age-related reference values and relevance in neurological disease.

We aimed to establish age-related reference values for Erythropoietin (EPO) in cerebrospinal fluid (CSF) and to evaluate concentrations in neurological diseases. CSF and serum EPO was measured in controls with tension-type headache (CTTH), in patients with ALS, dementia and depression using ELISA technique. Stability experiments showed CSF EPO to be stable for two and a half months and over two thaw/freeze cycles. A positive correlation of CSF EPO with age was found (P<0.01). We found a CSF/serum EPO concentration ratio of 0.126, pointing towards an intrathecal synthesis of EPO. The ALS group showed significantly lowered CSF EPO compared to age-matched CTTH (P<0.012), whereas the dementia and depression group showed no significant differences compared to CTTH.The establishment of age-related reference values in a large cohort of controls will improve the interpretation of future CSF EPO evaluations in neurological diseases.

Cerebrospinal fluid erythropoietin (EPO) in amyotrophic lateral sclerosis.

A candidate neuroprotective agent for neurodegenerative disorders is erythropoietin (EPO). We measured EPO in cerebrospinal fluid (CSF) and serum of patients with amyotrophic lateral sclerosis (ALS). Patients with ALS (N=60), Alzheimer's disease (AD, N=20) and age-matched controls (N=33) were included. Patients with ALS included 30 patients who showed a rapid progression of disease, and 30 patients that showed a slower progression. EPO was measured using ELISA technique. We found CSF EPO levels to be lower in ALS as compared to AD and controls (p<0.05), while no differences were found with regard to serum levels. Patients with ALS who showed a rapid disease progression had lower CSF EPO levels compared to those who progressed more slowly (p=0.03). Low CSF EPO in ALS may imply that the EPO-associated capacity to protect neurons from degeneration is impaired in ALS. Low concentrations of CSF EPO seem to point towards a rapid progression of disease that may be associated with a poorer prognosis.

High thrombopoietin concentrations in the cerebrospinal fluid of neonates with sepsis and intraventricular hemorrhage may contribute to brain damage.

Thrombopoietin (TPO) and its receptor (TPOR) are expressed in the central nervous system (CNS). Although TPO shares significant homology with various neurotrophins, recent data indicate a proapoptotic function of TPO in the CNS. In this study, TPO concentrations were analyzed in the cerebrospinal fluid (CSF) of neonates. Human neuroblastoma-derived SH-SY5Y cells were established to elucidate the effects of inflammation and hypoxia on neuronal Tpo expression. TPO was detectable in the CSF of 6 of 15 neonates with bacterial infection/sepsis (median 140, range 2-613 pg/mL), 5 of 9 neonates with posthemorrhagic hydrocephalus (median 31, range 1.4-469 pg/mL), 3 of 4 neonates with posthemorrhagic hydrocephalus plus bacterial infection/sepsis or meningitis (median 97, range 6-397 pg/mL), but not in controls ( n = 3). Neither the presence of detectable TPO nor its level in the CSF significantly correlated with any clinical or laboratory parameter. In SH-SY5Y cells, TPO and TPOR expression was detected by RT-PCR and Western blot analysis. In vitro, interleukin-6 (IL-6) did not significantly change Tpo gene expression. In contrast, Tpo mRNA expression significantly decreased under hypoxia, whereas erythropoietin (EPO) mRNA expression increased. In conclusion, our data provide evidence that in neuronal cells, TPO production is regulated by different mechanisms than in hepatocytes.

Functional and pharmacokinetic outcomes after a single intravenous infusion of recombinant human erythropoietin in patients with malignant extradural spinal cord compression.

AIMS: To determine the cerebrospinal fluid concentrations and the functional and pain outcomes after a single intravenous infusion of erythropoietin at the start of a standard radiotherapy and steroid protocol. MATERIALS AND METHODS: Ten paraparetic patients with malignant extradural spinal cord compression who were eligible for radiotherapy, lumbar puncture and intravenous epoetin alpha were enrolled. The patients received epoetin alpha 1500 IU/kg intravenously over 30 min followed by a standardised dexamethasone and radiotherapy protocol. A lumbar puncture and venipuncture were carried out 24-30 h after the epoetin alpha infusion. The patients were followed closely at defined intervals. RESULTS: Erythropoietin was detectable in the cerebrospinal fluid in all eight patients sampled (median 92.5 mIU/ml, range 17.8-214.0 mIU/ml). Before treatment, eight patients were non-ambulatory and two patients were ambulatory with assistance. After treatment, eight (80%, 95% confidence interval [CI] 44-97%) improved at least one functional class and recovered or maintained ambulation. Five of seven patients (71%; 95% CI 29-96%) with objective sensory deficits and one of seven (14%; 95% CI 0-58%) catheter-dependent patients recovered. Overall, 78% (95% CI 40-97%) had a pain response. CONCLUSIONS: After an intravenous infusion of epoetin alpha, radiotherapy and steroids, high concentrations of erythropoietin were detectable in the cerebrospinal fluid. Patients with malignant extradural spinal cord compression showed encouraging improvements in neurological function and pain.

High erythropoietin and low vascular endothelial growth factor levels in cerebrospinal fluid from hypoxemic ALS patients suggest an abnormal response to hypoxia.

Animal studies have highlighted the potentially neuroprotective role of vascular endothelial growth factor (VEGF). Low levels of this growth factor have been found in the cerebrospinal fluid (CSF) of patients with amyotrophic lateral sclerosis (ALS). VEGF (and other proteins, such as erythropoietin (EPO)) are produced in response to hypoxia via a common pathway involving a specific transcription factor (hypoxia-inducible factor, HIF) and a hypoxia responsive element (HRE) in the respective genes' promoter regions. In this study, we report finding the expected, high levels of VEGF and EPO in CSF from hypoxemic neurological controls, whereas EPO (but not VEGF) levels are high in the CSF from hypoxemic ALS patients. Hence, the VEGF levels in CSF from patients with ALS were significantly lower than those seen in hypoxemic controls. There was a trend towards higher CSF levels of EPO in hypoxemic ALS patients than in hypoxemic controls. Our results suggest that VEGF may not be produced in sufficient amounts in chronically hypoxic ALS patients and that this dysfunction may participate in the pathogenesis of the disease. The high EPO levels in hypoxemic ALS patients nevertheless suggest an intact common oxygen-sensor pathway.

Erythropoietin in the cerebrospinal fluid in neurodegenerative diseases.

Erythropoietin (EPO) and its specific receptor (EPOR) have been proposed to act as an endogenous system protecting against neuronal injury and neurodegeneration. We measured EPO in cerebrospinal fluid (CSF) of patients with neurodegenerative diseases, and tested for a correlation with an established biomarker of neuro-axonal damage, tau protein. Patients with Alzheimer's disease (AD, N=40), vascular dementia (VD, N=19), frontotemporal lobe dementia (FTLD, N=5), ALS (N=30) and controls (N=49) were included. Cerebrospinal fluid and serum levels of EPO and tau were measured using ELISA techniques. We found CSF EPO in ALS to be lower than in controls (p=0.04), while no difference between patients with AD, VD, FTLD and controls was detectable. CSF EPO correlated with age (p<0.001) as well as with tau protein (p=0.002) in all patients pooled. In contrast to the upregulation of the EPO/EPOR system in brain tissue upon various conditions of neuronal distress, CSF EPO concentrations in neurodegenerative disease were found in the same range or even reduced as compared to controls. This may be due to a relative deficiency of endogenous CNS EPO in these conditions and/or to a more efficient extraction of free EPO molecules from brain intercellular fluid by increased numbers of EPOR.

The pharmacokinetics of erythropoietin in the cerebrospinal fluid after intravenous administration of recombinant human erythropoietin.

OBJECTIVES: Erythropoietin (EPO) was originally described as a regulator of erythropoiesis. Recently, synthesis of EPO and expression of the EPO receptor (EPO-R) have been reported for the central nervous system (CNS). The potential use of EPO to prevent or reduce CNS injury and the paucity of information regarding its entry into the human CNS led us to examine the pharmacokinetics (PK) of recombinant human EPO (r-HuEPO) in the serum and cerebrospinal fluid (CSF). METHODS: Four patients with Ommaya reservoirs were enrolled to facilitate serial CSF sampling. R-HuEPO was given intravenously (IV) in single doses of 40,000 IU or 1,500 IU/kg and in multiple doses of 40,000 IU daily for 3 days. RESULTS: The EPO concentrations in the CSF increased after a period of slow equilibration. Linear first-order distribution kinetics were observed for serum and CSF. The concentration of EPO in the CSF was proportional to the serum concentration of EPO and the permeability of the blood-brain barrier (BBB), as determined by the albumin quotient (QA=[albumin] CSF/[albumin] serum). A rise in the CSF concentration was seen as early as 3 h after IV administration. Peak levels (C(max)) were reached between 9 h and 24 h. After a single dose of 1,500 IU/kg, the Cmax in the CSF ranged from 11 mIU/ml to 40 mIU/ml, and the ratios of CSF/serum Cmax ranged from 3.6x10-4 to 10.2x10-4. The terminal half-life (t1/2) values of EPO in serum and CSF were similar. The t(1/2) of r-HuEPO in the CSF ranged from 25.6 h to 35.5 h after a single dose of 1,500 IU/l. Using these parameters a PK model was generated that predicts the concentration-time profile of EPO in the CSF. CONCLUSIONS: We report that r-HuEPO can cross the human BBB and describe for the first time the PK of EPO in the CSF after IV administration. Our data suggest that the concentration-time profile of EPO in the CSF can be predicted for individual patients if the serum concentration of EPO and the Q(A) are known. This information may be useful in the design of clinical trials to explore the potential therapeutic effects of EPO during CNS injury.