Neuroprotective activity of a new erythropoietin formulation with increased penetration in the central nervous system
© Etcheverrigaray et al; licensee BioMed Central Ltd. 2011
Published: 22 November 2011
Apart from its hematopoietic effect, erythropoietin (EPO) is a molecule with high neuroprotective potential. However, its prolonged application may cause serious adverse effects due to the erythropoiesis stimulation. Therefore, an EPO derivative with neuroprotective properties but low hematopoietic activity, designated as neuropoietin (rhNEPO), was developed in our lab using an alternative purification process of the recombinant human erythropoietic counterpart (rhEPO) produced in CHO cells . The in vitro cytoprotective activity of rhNEPO on neural phenotype cells and its brain uptake from blood are herein analyzed.
In vitro citoprotective activity of rhNEPO was analyzed on rat pheochromocytoma cells (PC-12) differentiated to neural phenotype with neural growth factor (NGF). Apoptosis was triggered by NGF and serum withdrawal from cell cultures. Thus, nuclear DNA fragmentation was analyzed by colorimetric TUNEL detection. One-way analysis of variance was carried out followed by Dunnett´s multiple comparison test. Probabilities lower than 0.05 were considered significant (p<0.05).
Taking into account the cytoprotective activity of rhNEPO on neural phenotype cells, cerebrospinal fluid (CSF) and blood pharmacokinetics of rhEPO and rhNEPO were evaluated in rats following intravenous administration of a single dose of each protein, aiming to evaluate their CSF uptake from plasma.
The distribution and the elimination half-lives of rhNEPO in blood were significantly shorter than the corresponding ones for rhEPO. Differences in the sialic acid content and oligosaccharide anntenarity status  may describe the faster elimination rate of rhNEPO. Thus, this derivative, which is a less sialylated and less branched molecule, was rapidly cleared from blood but reached the CSF in a shorter time (5 min vs 30 min of rhEPO) at concentrations high enough to bind to the EPO receptors. Consequently, the faster transport through the blood-brain-barrier (BBB) might accelerate rhNEPO distribution into the nervous system, causing a faster appearance into the action site. Moreover, the rapid clearance of rhNEPO from plasma represents an advantage in the treatment of neurological diseases, because the continuous presence of EPO in blood is the stimulus that triggers the production of sanguineous cells with the resulting appearance of adverse side-effects.
Pharmacokinetics of rhEPO and rhNEPO in plasma and CSF after intravenous administration of a single dose of 500 µg of each protein in rats. The quantification of EPO derivatives were carried out by sandwich ELISA .
t 1/2α (h) a
t 1/2β (h) b
t CSF ( min ) c
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