RESUMEN
Acute stroke is one of the major causes of death and disabilities. Since the 1980s many clinical studies have been conducted to evaluate neuroprotective approaches to treat this important brain vascular event. However, to date the only drug approved (recombinant tissue plasminogen activator [rtPA]) represents a thrombolytic, nonneuroprotective approach. An important neuroprotective strategy is based on erythropoietin (EPO). Exogenously administered EPO exhibits neuroprotective effects in numerous animal models, through the activation of anti-apoptotic, anti-oxidant and anti-inflammatory pathways as well as through the stimulation of angiogenic and neurogenic events. The capability of EPO to cross the blood-brain barrier after systemic administration and its effective therapeutic window are advantages for human acute stroke therapy. However, a multicenter stroke trial where recombinant human EPO (rhEPO) was combined with rtPA had negative outcomes. The present paper reviews the EPO neuroprotective strategy and its mechanisms in ischemic stroke and in other human nervous system diseases.
RESUMEN
The Mongolian gerbil has been widely used as a global brain ischemia model because of its incomplete cerebral circle of Willis. However, the inter-individual anatomic variability of this vascular structure interferes with the reliability of the model. The aim of this work was to introduce modifications to the protocol of global brain ischemia experiments in Mongolian gerbils in an attempt to increase the reliability and usefulness of this model. Our study focused on the assessment of the level of anastomosis of the cerebral circle of Willis in order to evaluate its contribution to clinicopathological outcomes in this model. Sham-operated, Ischemic, and Ischemic + Hypothermia animals were subjected to a 15-minute occlusion of the common carotid arteries. Transcardiac perfusion with bromophenol blue / gelatin solution was performed 72 hours after ischemia. Brains were processed for anatomopathological analysis. Tissue damage was observed in the hippocampus, caudate-putamen nucleus, neocortex, and thalamic nuclei of animals from the Ischemic group. The circles of Willis of the Sham-operated animals showed bilateral (38 percent), unilateral (48 percent) or no posterior communicating arteries (14 percent). A negative correlation between infarct volume and the level of anastomosis was revealed for the Ischemic, but not for the Ischemic + Hypothermia group. Additionally, Analysis of covariance (ANCOVA) was performed to assess the contribution of the level of anastomosis to the clinicopathological outcomes. It was confirmed that the infarct volume decreased in the Ischemic + Hypothermia group when compared to the Ischemic group. Since the level of anastomosis cannot be predicted, this variable should necessarily be considered when analyzing the results of global brain ischemia in Mongolian gerbils.
Asunto(s)
Isquemia Encefálica/patología , Círculo Arterial Cerebral/fisiopatología , Modelos Animales de Enfermedad , Hipocampo/patología , Análisis de Varianza , Animales , Infarto Encefálico/prevención & control , Isquemia Encefálica/terapia , Recuento de Células , Lateralidad Funcional , Gerbillinae , Hipocampo/metabolismo , Hipotermia Inducida/métodos , Masculino , Examen NeurológicoRESUMEN
PURPOSE: Multiple sclerosis is a complex and devastating autoimmune disease of the central nervous system. Up to now, a constellation of candidate drugs have been evaluated with no major success. Experimental Autoimmune Encephalitis (EAE) is the animal counterpart that reproduces critical features of the human MS process. The aim of the present work is to study a possible therapeutic effect of epidermal growth factor (EGF) and growth hormone releasing peptide-6 (GHRP(6)) coadministration in mild and severe EAE. METHODS: Mild and severe forms of EAE were generated immunizing rats and mice with xenogeneic spinal cord homogenate and with the encephalitogenic peptide MOG(p35-35), respectively. EGF and GHRP(6) alone or combined were administered in therapeutic and prophylactic schedules. A clinical score was established to follow-up the animals during the disease period. Malondialdehyde (MDA) serum concentration and insulin like growth factor-1 (IGF-1) relative level from brain tissue were determined. RESULTS: Only the combined EGF+GHRP(6) therapy reduced the clinical score in mild as well in severe EAE forms. The combination also improved the survival rate in nearly 100% of the severe EAE animals. In addition to these effects, there was an increase in the brain IGF-1 transcript and a decrease of serum MDA. CONCLUSIONS: EGF+GHRP(6) proved to be effective in improving the natural course of both mild and severe EAE. Accordingly, the treatment reduces inflammatory infiltration and microvascular damage, which may be associated to the attenuation of the lipid peroxidation process and the transcriptional enhancement of IGF-1, a major pro-survival factor for brain cells.