Giovanni Grasso and Alessandra Sfacteria
Fabio Torregrossa and Giovanni Grasso
Concetta Alafaci, Francesco M. Salpietro, Giovanni Grasso, Gaspare Montemagno, Sebastiano Lucerna, Domenico Matalone, Antonio Morabito, and Francesco Tomasello
Giovanni Grasso, Francesco Meli, Vincenzo Fodale, Gioacchino Calapai, Michele Buemi, and Domenico G. Iacopino
The objectives of this study were to examine whether the systemic administration of recombinant human erythropoietin (rHuEPO) and its long-lasting derivative darbepoetin alfa expedited functional recovery in a rat model of sciatic nerve injury, and to compare the effects of these agents in the model.
Thirty male Sprague–Dawley rats received a crush injury to the left sciatic nerve and subsequently underwent either placebo treatment, daily injections of rHuEPO, or weekly injections of darbepoetin alfa.
Both rHuEPO and darbepoetin alfa were effective in reducing neurological impairment and improving compound muscle action potentials following nerve injury. Darbepoetin alfa, however, shortened the duration of peripheral nerve recovery and facilitated recovery from the neurological and electrophysiological impairment following crush injury significantly better than rHuEPO. Examination of the footprint length factor data revealed that darbepoetin alfa–treated animals recovered preinjury function by postoperative Day 10, 4 days earlier than animals treated with rHuEPO and 11 days earlier than animals treated with placebo.
These results suggest that recovery of neurological function in a model of peripheral nerve injury is more rapid with weekly administration of darbepoetin alfa than with daily rHuEPO treatment. Agents that facilitate nerve regeneration have the potential to limit the extent of motor endplate loss and muscle atrophy. The administration of EPO in its long-lasting recombinant forms affords significant neuroprotection in peripheral nerve injury models and may hold promise for future clinical applications.
Giovanni Grasso, Marcello Passalacqua, Alessandra Sfacteria, Alfredo Conti, Antonio Morabito, Giuseppe Mazzullo, Gionata De Vico, Michele Buemi, Battesimo Macrì, and Francesco Tomasello
Object. Results of recent studies indicate that erythropoietin (EPO) produces a neuroprotective effect on experimental subarachnoid hemorrhage (SAH). It has been reported that S-100 protein levels increase in cerebrospinal fluid (CSF) after SAH, providing a highly prognostic indication of unfavorable outcome. This study was conducted to validate further the findings of S-100 protein as an index of brain damage and to assess whether treatment with recombinant human EPO (rhEPO) would limit the increase of S-100 protein level in CSF following experimental SAH.
Methods. Thirty-two rabbits were each assigned to one of four groups: Group 1, control; Group 2, SAH; Group 3, SAH plus placebo; and Group 4, SAH plus rhEPO (each group consisted of eight rabbits). The rhEPO and placebo were administered to the rabbits after SAH had been induced, and S-100 protein levels in the CSF of these animals were measured at 24, 48, and 72 hours after the experimental procedure. In each group of animals levels of S-100 protein were compared with the mortality rate, neurological outcome, and neuronal ischemic damage. High S-100 protein levels were found in rabbits in Groups 2 and 3, which exhibited poor neurological status and harbored a high number of damaged cortical neurons. Favorable neurological outcome and significant reductions in total numbers of damaged neurons were observed in animals in Group 4 in which there were significantly lower S-100 protein concentrations compared with animals in Groups 2 and 3 (p < 0.001).
Conclusions. The results of this study support the concept that determination of the S-100 protein level in CSF has prognostic value after SAH. The findings also confirm that rhEPO acts as a neuroprotective agent during experimental SAH.
Rosa Morabito, Giovanni Grasso, Valeria Barresi, Paolo La Spina, Giada Garufi, Elisabetta Alafaci, Francesco M. Salpietro, Marcello Longo, Francesca Granata, and Concetta Alafaci
Giovanni Grasso, Alessandra Sfacteria, Serhat Erbayraktar, Marcello Passalacqua, Francesco Meli, Necati Gokmen, Osman Yilmaz, Domenico La Torre, Michele Buemi, Domenico G. Iacopino, Thomas Coleman, Anthony Cerami, Michael Brines, and Francesco Tomasello
Spinal cord injury (SCI) is a devastating clinical syndrome for which no truly efficacious therapy has yet been identified. In preclinical studies, erythropoietin (EPO) and its nonerythropoietic derivatives asialoEPO and carbamylated EPO have markedly improved functional outcome when administered after compressive SCI. However, an optimum treatment paradigm is currently unknown. Because the uninjured spinal cord expresses a high density of EPO receptor (EPOR) in the basal state, signaling through these existing receptors in advance of injury (pharmacological preconditioning) might confer neuroprotection and therefore be potentially useful in situations of anticipated damage.
The authors compared asialoEPO, a molecule that binds to the EPOR with high affinity but with a brief serum half-life (t1/2 < 2 minutes), to EPO to determine whether a single dose (10 μg/kg of body weight) administered by intravenous injection 24 hours before 1 minute of spinal cord compression provides benefit as determined by a 6-week assessment of neurological outcome and by histopathological analysis. Rats pretreated with asialoEPO or EPO and then subjected to a compressive injury exhibited improved motor function over 42 days, compared with animals treated with saline solution. However, pretreatment efficacy was substantially poorer than efficacy of treatment initiated at the time of injury. Serum samples drawn immediately before compression confirmed that no detectable asialoEPO remained within the systemic circulation. Western blot and immunohistochemical analyses performed using uninjured spinal cord 24 hours after a dose of asialoEPO exhibited a marked increase in glial fibrillary acidic protein, suggesting a glial response to EPO administration.
These results demonstrate that EPO and its analog do not need to be present at the time of injury to provide tissue protection and that tissue protection is markedly effective when either agent is administered immediately after injury. Furthermore, the findings suggest that asialoEPO is a useful reagent with which to study the dynamics of EPO-mediated neuroprotection. In addition, the findings support the concept of using a nonerythropoietic EPO derivative to provide tissue protection without activating the undesirable effects of EPO.