Erythropoietin: still on the neuroprotection road.

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.

Global brain ischemia in Mongolian gerbils: assessing the level of anastomosis in the cerebral circle of Willis.

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.

Coadministration of epidermal growth factor and growth hormone releasing peptide-6 improves clinical recovery in experimental autoimmune encephalitis.

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.

Therapeutic effect of the combined use of growth hormone releasing peptide-6 and epidermal growth factor in an axonopathy model.

Amyotrophic lateral sclerosis (ALS) is a disease of the central nervous system characterized by loss of spinal motor neurons, for which no effective treatment exists. Epidermal growth factor (EGF) and growth hormone releasing peptide-6 (GHRP-6) have been considered as good candidates for the treatment of this disease, due to their well documented effects in eliciting pleiotrophic and cell survival mechanisms. The aim of the present work was to evaluate the separate and combined effects of both peptides in an experimental animal model of ALS, the proximal axonopathy induced by 1,2 diacetylbenzene (1,2 DAB) in mice. The evaluations were conducted by means of behavioral tests (trapeze, tail suspension, gait pattern, and open field) and by recording the complex muscle action potential (CMAP) in three different hind limb segments: proximal S1, medial S2, and distal S3. Intraperitoneal daily administration of 1,2 DAB produced significant reduction in body weight, muscle strength, extensor reflex, spontaneous activity, and changes in gait pattern parameters. In parallel 1,2 DAB produced significant prolongation of onset latency and decrease in amplitude of CMAP and in the integrated complex action potential index. Daily administration of the separate compounds did not accelerate the recovery of the affected parameters, except for the gait pattern. The combined treatment produced significant improvement in behavioral parameters, as well as in electrophysiological recovery, particularly in the proximal segment of CMAP. The latter results confirm the proximal character of 1,2 DAB neuropathy, and suggest that combined therapy with EGF and GHRP-6 might be a good therapeutic strategy for the treatment of ALS.

The pro-inflammatory environment in recalcitrant diabetic foot wounds.

Lower extremity ulceration is one of the serious and long-term diabetic complications rendering a significant social burden in terms of amputation and quality-of-life reduction. Diabetic patients experience a substantial wound-healing deficit. These lesions are featured by an exaggerated and prolonged inflammatory reaction with a significant impairment in local bacterial invasion control. Experimental and clinical evidences document the deleterious consequences of the wound's pro-inflammatory phenotype for the repair process. From a biochemical standpoint, hyperinflammation favours wound matrix degradation, thus, amplifying a pre-existing granulation tissue productive cells' invasiveness and recruitment deficit. Tumour necrosis factor perpetuates homing of inflammatory cells, triggers pro-apoptotic genes and impairs reepithelialisation. Advanced glycation end-products act in concert with inflammatory mediators and commit fibroblasts and vascular cells to apoptosis, contributing to granulation tissue demise. Therapeutic approaches aimed to downregulate hyperinflammation and/or attenuate glucolipotoxicity may assist in diabetic wound healing by dismantling downstream effectors. These medical interventions are demanded to reduce amputations in an expanding diabetic population.

Boosting controlled autoimmunity: a new therapeutic target for CNS disorders.

In most tissues, the immune system plays an essential role in protection, repair and healing. Although immunologically privileged, the CNS remains subject to a highly regulated form of immunosurveillance that is of increasing interest. There is evolving evidence that repair mechanisms within the CNS may be enhanced by exploiting an innate process of protective immunity. Understanding the regulation of protective autoimmunity within the CNS is likely to lead to novel therapeutic approaches to neuroinflammatory and neurodegenerative diseases.