Copolymer-1 promotes neurogenesis and improves functional recovery after acute ischemic stroke in rats

Electrophysiological and histopathological evaluation of the effectiveness of melatonin and glatiramer acetate for traumatic facial nerve injuries

AIM

This study aimed to evaluate the effect of systemic/local use of melatonin and glatiramer acetate on regeneration in traumatic nerve injury models.

MATERIALS AND METHODS

A total of 42 male Wistar albino rats were randomly divided into 6 groups: healthy control (Group 1), injured control (Group 2), local melatonin (Group 3), systemic melatonin (Group 4), local glatiramer acetate (Group 5), and systemic glatiramer acetate (Group 6). In all groups, electromyography recordings of the facial nerve were obtained after surgery and before sacrifice, and the damaged nerve region was histopathologically examined after sacrifice.

RESULTS

In the electrophysiological evaluation, the control group had the greatest decrease in amplitude and extension in latency time following surgery than the treatment groups. Furthermore, a significant decrease in the degenerative axon count, edematous areas, and fibrotic areas as well as a significant increase in axonal surface areas was observed in all the treatment groups compared with the damage control group.

CONCLUSIONS

Although both glatiramer acetate and melatonin are beneficial in regeneration in traumatic facial nerve injuries, it can be concluded that systemic use of melatonin can yield more positive results than glatiramer acetate and local use of both two drugs.

Immunosenescence as a convergence pathway in neurodegeneration

Immunity refers to the body's defense mechanism to protect itself against illness or to produce antibodies against pathogens. Senescence is a cellular phenomenon that integrates a sustainable growth restriction, other phenotypic abnormalities and including a pro-inflammatory secretome. It is highly involved in regulating developmental stages, tissue homeostasis, and tumor proliferation monitoring. Contemporary experimental reports imply that abolition of senescent cells employing evolved genetic and therapeutic approaches augment the chances of survival and boosts the health span of an individual. Immunosenescence is considered as a process in which dysfunction of the immune system occurs with aging and greatly includes remodeling of lymphoid organs. This in turn causes fluctuations in the immune function of the elderly that has strict relation with the expansion of autoimmune diseases, infections, malignant tumors and neurodegenerative disorders. The interaction of the nervous and immune systems during aging is marked by bi-directional influence and mutual correlation of variations. The enhanced systemic inflammatory condition in the elderly, and the neuronal immune cell activity can be modulated by inflamm-aging and peripheral immunosenescence resulting in chronic low-grade inflammatory processes in the central Nervous system known as neuro-inflammaging. For example, glia excitation by cytokines and glia pro-inflammatory productions contribute significantly to memory injury as well as in acute systemic inflammation, which is associated with high levels of Tumor necrosis factor -α and a rise in cognitive decline. In recent years its role in the pathology of Alzheimer's disease has caught research interest to a large extent. This article reviews the connection concerning the immune and nervous systems and highlights how immunosenescence and inflamm-aging can affect neurodegenerative disorders.

Copolymer-1 as a potential therapy for mild cognitive impairment

Mild cognitive impairment (MCI) is a prodromal stage of memory impairment that may precede dementia. MCI is classified by the presence or absence of memory impairment into amnestic or non-amnestic MCI, respectively. More than 90% of patients with amnestic MCI who progress towards dementia meet criteria for Alzheimer's disease (AD). A combination of mechanisms promotes MCI, including intracellular neurofibrillary tangle formation, extracellular amyloid deposition, oxidative stress, neuronal loss, synaptodegeneration, cholinergic dysfunction, cerebrovascular disease, and neuroinflammation. However, emerging evidence indicates that neuroinflammation plays an important role in the pathogenesis of cognitive impairment. Unfortunately, there are currently no Food and Drug Administration (FDA)-approved drugs for MCI. Copolymer-1 (Cop-1), also known as glatiramer acetate, is a synthetic polypeptide of four amino acids approved by the FDA for the treatment of relapsing-remitting multiple sclerosis. Cop-1 therapeutic effect is attributed to immunomodulation, promoting a switch from proinflammatory to anti-inflammatory phenotype. In addition to its anti-inflammatory properties, it stimulates brain-derived neurotrophic factor (BDNF) secretion, a neurotrophin involved in neurogenesis and the generation of hippocampal long-term potentials. Moreover, BDNF levels are significantly decreased in patients with cognitive impairment. Therefore, Cop-1 immunization might promote synaptic plasticity and memory consolidation by increasing BDNF production in patients with MCI.

Glatiramer Acetate Immunomodulation: Evidence of Neuroprotection and Cognitive Preservation

Novel, neuroprotective uses of Copaxone (generic name: glatiramer acetate-GA) are being examined, primarily in neurological conditions involving cognitive decline. GA is a well-studied synthetic copolymer that is FDA-approved for immune-based treatment of relapsing remitting multiple sclerosis (RRMS). Clinical studies have explored the potential mechanism of action (MOA) and outcomes of GA immunization in patients. Furthermore, results from these and animal studies suggest that GA has a direct immunomodulatory effect on adaptive and innate immune cell phenotypes and responses. These MOAs have been postulated to have a common neuroprotective impact in several neuroinflammatory and neurodegenerative diseases. Notably, several clinical studies report that the use of GA mitigated MS-associated cognitive decline. Its propensity to ameliorate neuro-proinflammatory and degenerative processes ignites increased interest in potential alternate uses such as in age-related macular degeneration (AMD), amyotrophic lateral sclerosis (ALS), and Alzheimer's disease (AD). Preclinical studies are exploring less frequent subcutaneous administration of GA, such as once weekly or monthly or a single dosing regimen. Indeed, cognitive functions were found to be either preserved, reversed, or improved after the less frequent treatment regimens with GA in animal models of AD. In this systematic review, we examine the potential novel uses of GA across clinical and pre-clinical studies, with evidence for its beneficial impact on cognition. Future investigation in large-size, double-blind clinical trials is warranted to establish the impact of GA immunomodulation on neuroprotection and cognitive preservation in various neurological conditions.

Immunomodulation induced by central nervous system-related peptides as a therapeutic strategy for neurodegenerative disorders

Neurodegenerative diseases (NDD) are disorders characterized by the progressive loss of neurons affecting motor, sensory, and/or cognitive functions. The incidence of these diseases is increasing and has a great impact due to their high morbidity and mortality. Unfortunately, current therapeutic strategies only temporarily improve the patients' quality of life but are insufficient for completely alleviating the symptoms. An interaction between the immune system and the central nervous system (CNS) is widely associated with neuronal damage in NDD. Usually, immune cell infiltration has been identified with inflammation and is considered harmful to the injured CNS. However, the immune system has a crucial role in the protection and regeneration of the injured CNS. Nowadays, there is a consensus that deregulation of immune homeostasis may represent one of the key initial steps in NDD. Dr. Michal Schwartz originally conceived the concept of "protective autoimmunity" (PA) as a well-controlled peripheral inflammatory reaction after injury, essential for neuroprotection and regeneration. Several studies suggested that immunizing with a weaker version of the neural self-antigen would generate PA without degenerative autoimmunity. The development of CNS-related peptides with immunomodulatory neuroprotective effect led to important research to evaluate their use in chronic and acute NDD. In this review, we refer to the role of PA and the potential applications of active immunization as a therapeutic option for NDD treatment. In particular, we focus on the experimental and clinical promissory findings for CNS-related peptides with beneficial immunomodulatory effects.

Synergic Neuroprotection Between Ligusticum Chuanxiong Hort and Borneol Against Ischemic Stroke by Neurogenesis via Modulating Reactive Astrogliosis and Maintaining the Blood-Brain Barrier

Background:Ligusticum chuanxiong Hort (LCH) is a famous ethnomedicine in Asia known for its excellent output on stroke treatment, and borneol usually acts as an assistant for its reducing permeability of the blood–brain barrier (BBB) after stroke. Although their synergy against brain ischemia was verified in previous studies, the potential mechanism is still unknown.

Methods: The research aimed to explore the exact synergic mechanisms between LCH and borneol on neurogenesis within the areas of the dentate gyrus and subventricular zone. After treating middle cerebral artery occlusion rats with LCH (0.1 g/kg) and/or borneol (0.08 g/kg), the neurological severity score, brain infarct ratio, Nissl staining, Evans blue permeability, BBB ultrastructure, and expressions of von Willebrand factor and tight junction–associated proteins were measured. Co-localizations of Nestin⁺/BrdU⁺ and doublecortin⁺/BrdU⁺, and expressions of neuronal nuclei (NeuN) and glial fibrillary acidic protein (GFAP) were observed under a fluorescence microscope. Moreover, astrocyte polarization markers of complement component 3 and pentraxin 3, and relevant neurotrophins were also detected by immunoblotting.

Results: Basically, LCH and borneol had different focuses, although both of them decreased infarct areas, and increased quantity of Nissl bodies and expression of brain-derived neurotrophic factor. LCH increased the neurological severity score, NeuN⁺ cells, and the ratios of Nestin⁺/BrdU⁺ and doublecortin⁺/BrdU⁺, and decreased GFAP⁺ cells and ciliary neurotrophic factor expression. Additionally, it regulated the expressions of complement component 3 and pentraxin 3 to transform astrocyte phenotypes. Borneol improved BBB ultrastructure and increased the expressions of von Willebrand factor, tight junction–associated proteins, vascular endothelial growth factor, and vascular endothelial growth factor receptor 2. Unexpectedly, their combined therapy showed more obvious regulations on the Nissl score, Evans blue permeability, doublecortin⁺/BrdU⁺, NeuN⁺ cells, brain-derived neurotrophic factor, and vascular endothelial growth factor than both of their monotherapies.

Conclusions: The results indicated that LCH and borneol were complementary to each other in attenuating brain ischemia by and large. LCH mainly promoted neural stem cell proliferation, neurogenesis, and mature neuron preservation, which was probably related to the transformation of reactive astrocytes from A1 subtype to A2, while borneol preferred to maintain the integrity of the BBB, which provided neurogenesis with a homeostatic environment.

Long Non-coding RNAs as Promising Therapeutic Approach in Ischemic Stroke: a Comprehensive Review

In recent years, ischemic stroke (IS) has been one of the major causes of disability and mortality worldwide. The general mechanism of IS is based on reduced blood supply to neuronal tissue, resulting in neuronal cell damage by various pathological reactions. One of the main techniques for acute IS treatment entails advanced surgical approaches for restoration of cerebral blood supply but this is often associated with secondary brain injury, also known as ischemic reperfusion injury (I/R injury). Many researches have come to emphasize the significant role of long non-coding RNAs (lncRNAs) in IS, especially in I/R injury and their potential as therapeutic approaches. LncRNAs are non-protein transcripts that are able to regulate cellular processes and gene expression. Further, lncRNAs have been shown to be involved in neuronal signaling pathways. Several lncRNAs are recognized as key factors in the physiological and pathological processes of IS. In this review, we discuss the role of lncRNAs in neuronal injury mechanisms and their association with brain neuroprotection. Moreover, we identify the lncRNAs that show the greatest potential as novel therapeutic approaches in IS, which therefore merit further investigation in preclinical research. Graphical Abstract.

Thinking outside the Ischemia Box: Advancements in the Use of Multiple Sclerosis Drugs in Ischemic Stroke

Ischemic stroke (IS) is a major cause of death and disability, despite early intervention. Thrombo-inflammation, the inflammatory process triggered by ischemia, is a concept that ties IS with multiple sclerosis (MS), under the wider ‘umbrella’ of neuroinflammation, i.e., the inflammation of the nervous tissue. Drawing from this, numerous studies have explored the potential of MS disease-modifying drugs in the setting of IS. In this review, we present the available studies and discuss their potential in ameliorating IS outcomes. Based on our search, the vast majority of the studies have been conducted on animals, yielding mostly positive results. Two clinical trials involving natalizumab showed that it does not confer any benefits, but four human studies regarding fingolimod have showcased its potential in improving recovery prospects. However, concerns on safety and other issues are raised, and basic questions still need to be answered.

Blood-Brain Barrier Damage in Ischemic Stroke and Its Regulation by Endothelial Mechanotransduction

Ischemic stroke, a major cause of mortality in the United States, often contributes to disruption of the blood-brain barrier (BBB). The BBB along with its supportive cells, collectively referred to as the “neurovascular unit,” is the brain’s multicellular microvasculature that bi-directionally regulates the transport of blood, ions, oxygen, and cells from the circulation into the brain. It is thus vital for the maintenance of central nervous system homeostasis. BBB disruption, which is associated with the altered expression of tight junction proteins and BBB transporters, is believed to exacerbate brain injury caused by ischemic stroke and limits the therapeutic potential of current clinical therapies, such as recombinant tissue plasminogen activator. Accumulating evidence suggests that endothelial mechanobiology, the conversion of mechanical forces into biochemical signals, helps regulate function of the peripheral vasculature and may similarly maintain BBB integrity. For example, the endothelial glycocalyx (GCX), a glycoprotein-proteoglycan layer extending into the lumen of bloods vessel, is abundantly expressed on endothelial cells of the BBB and has been shown to regulate BBB permeability. In this review, we will focus on our understanding of the mechanisms underlying BBB damage after ischemic stroke, highlighting current and potential future novel pharmacological strategies for BBB protection and recovery. Finally, we will address the current knowledge of endothelial mechanotransduction in BBB maintenance, specifically focusing on a potential role of the endothelial GCX.

Immunization with neural-derived peptides increases neurogenesis in rats with chronic spinal cord injury

Aims

Immunization with neural‐derived peptides (INDP) has demonstrated to be a promising therapy to achieve a regenerative effect in the chronic phase of the spinal cord injury (SCI). Nevertheless, INDP‐induced neurogenic effects in the chronic stage of SCI have not been explored.

Methods and Results

In this study, we analyzed the effect of INDP on both motor and sensitive function recovery; afterward, we assessed neurogenesis and determined the production of cytokines (IL‐4, IL‐10, and TNF alpha) and neurotrophic factors (BDNF and GAP‐43). During the chronic stage of SCI, rats subjected to INDP showed a significant increase in both motor and sensitive recovery when compared to the control group. Moreover, we found a significant increase in neurogenesis, mainly at the central canal and at both the dorsal and ventral horns of INDP‐treated animals. Finally, INDP induced significant production of antiinflammatory and regeneration‐associated proteins in the chronic stages of SCI.

Conclusions

These findings suggest that INDP has a neurogenic effect that could improve motor and sensitive recovery in the chronic stage of SCI. Moreover, our results also envision the use of INDP as a possible therapeutic strategy for other trauma‐related disorders like traumatic brain injury.

B cells migrate into remote brain areas and support neurogenesis and functional recovery after focal stroke in mice

Neuroinflammation occurs immediately after stroke onset in the ischemic infarct, but whether neuroinflammation occurs in remote regions supporting plasticity and functional recovery remains unknown. We used advanced imaging to quantify whole-brain diapedesis of B cells, an immune cell capable of producing neurotrophins. We identify bilateral B cell diapedesis into remote regions, outside of the injury, that support motor and cognitive recovery in young male mice. Poststroke depletion of B cells confirms a positive role in neurogenesis, neuronal survival, and recovery of motor coordination, spatial learning, and anxiety. More than 80% of stroke survivors have long-term disability uniquely affected by age and lifestyle factors. Thus, identifying beneficial neuroinflammation during long-term recovery increases the opportunity of therapeutic interventions to support functional recovery.

Lymphocytes infiltrate the stroke core and penumbra and often exacerbate cellular injury. B cells, however, are lymphocytes that do not contribute to acute pathology but can support recovery. B cell adoptive transfer to mice reduced infarct volumes 3 and 7 d after transient middle cerebral artery occlusion (tMCAo), independent of changing immune populations in recipient mice. Testing a direct neurotrophic effect, B cells cocultured with mixed cortical cells protected neurons and maintained dendritic arborization after oxygen-glucose deprivation. Whole-brain volumetric serial two-photon tomography (STPT) and a custom-developed image analysis pipeline visualized and quantified poststroke B cell diapedesis throughout the brain, including remote areas supporting functional recovery. Stroke induced significant bilateral B cell diapedesis into remote brain regions regulating motor and cognitive functions and neurogenesis (e.g., dentate gyrus, hypothalamus, olfactory areas, cerebellum) in the whole-brain datasets. To confirm a mechanistic role for B cells in functional recovery, rituximab was given to human CD20⁺ (hCD20⁺) transgenic mice to continuously deplete hCD20⁺-expressing B cells following tMCAo. These mice experienced delayed motor recovery, impaired spatial memory, and increased anxiety through 8 wk poststroke compared to wild type (WT) littermates also receiving rituximab. B cell depletion reduced stroke-induced hippocampal neurogenesis and cell survival. Thus, B cell diapedesis occurred in areas remote to the infarct that mediated motor and cognitive recovery. Understanding the role of B cells in neuronal health and disease-based plasticity is critical for developing effective immune-based therapies for protection against diseases that involve recruitment of peripheral immune cells into the injured brain.

Glatiramer acetate reduces infarct volume in diabetic mice with cerebral ischemia and prevents long-term memory loss

Stroke is currently the second leading cause of death in industrialized countries and the second cause of dementia after Alzheimer's disease. Diabetes is an independent risk factor for stroke that exacerbates the severity of lesions, disability and cognitive decline. There is increasing evidence that sustained brain inflammation may account for this long-term prejudicial outcome in diabetic patients in particular. We sought to demonstrate that experimental permanent middle cerebral artery occlusion (pMCAo) in the diabetic mouse aggravates stroke, induces cognitive decline, and is associated with exacerbated brain inflammation, and that these effects can be alleviated and/or prevented by the immunomodulator, glatiramer acetate (GA). Male diabetic C57Bl6 mice (streptozotocin IP) subjected to permanent middle cerebral artery occlusion (pMCAo), were treated by the immunomodulator, GA (Copaxone®) (1 mg/kg daily, sc) until 3 or 7 days post stroke. Infarct volume, brain pro- and anti-inflammatory mediators, microglial/macrophage density, and neurogenesis were monitored during the first week post stroke. Neurological sensorimotor deficit, spatial memory and brain deposits of Aβ40 and Aβ42 were assessed until six weeks post stroke. In diabetic mice with pMCAo, proinflammatory mediators (IL-1β, MCP1, TNFα and CD68) were significantly higher than in non-diabetic mice. In GA-treated mice, the infarct volume was reduced by 30% at D3 and by 40% at D7 post stroke (P < 0.05), sensorimotor recovery was accelerated as early as D3, and long-term memory loss was prevented. Moreover, proinflammatory mediators significantly decreased between D3 (COX2) and D7 (CD32, TNFα, IL-1β), and neurogenesis was significantly increased at D7. Moreover, GA abrogates the accumulation of insoluble Aβ40. This work is the first one to evidence that the immunomodulatory drug GA reduces infarct volume and proinflammatory mediators, enhances early neurogenesis, accelerates sensorimotor recovery, and prevents long-term memory loss in diabetic mice with pMCAo.

Autoimmunity in acute ischemic stroke and the role of blood-brain barrier: the dark side or the light one?

This article presents a synopsis of the current data on the mechanisms of blood-brain barrier (BBB) alteration and autoimmune response in acute ischemic stroke. Most researchers confirm the relationship between the severity of immunobiochemical changes and clinical outcome of acute ischemic stroke. Ischemic stroke is accompanied by aseptic inflammation, which alters the brain tissue and exposes the co-stimulatory molecules of the immune system and the neuronal antigens. To date, BBB is not considered the border between the immune system and central nervous system, and the local immune subsystems are found within and behind the BBB. BBB disruption contributes to the leakage of brain autoantigens and induction of secondary autoimmune response to neuronal antigens and long-term inflammation. Glymphatic system function is altered and jeopardized both in hemorrhagic and ischemic stroke types. The receptors of innate immunity (toll-like receptor-2 and toll-like receptor-4) are also involved in acute ischemia-reperfusion injury. Immune response is related to the key processes of blood clotting and fibrinolysis. At the same time, the stroke-induced immune activation may promote reparation phenomena in the brain. Subsequent research on the reduction of the acute ischemic brain injury through the target regulation of the immune response is promising.

Use of a combination strategy to improve neuroprotection and neuroregeneration in a rat model of acute spinal cord injury

Spinal cord injury is a very common pathological event that has devastating functional consequences in patients. In recent years, several research groups are trying to find an effective therapy that could be applied in clinical practice. In this study, we analyzed the combination of different strategies as a potential therapy for spinal cord injury. Immunization with neural derived peptides (INDP), inhibition of glial scar formation (dipyridyl: DPY), as well as the use of biocompatible matrix (fibrin glue: FG) impregnated with bone marrow mesenchymal stem cells (MSCs) were combined and then its beneficial effects were evaluated in the induction of neuroprotection and neuroregeneration after acute SCI. Sprague-Dawley female rats were subjected to a moderate spinal cord injury and then randomly allocated into five groups: 1) phosphate buffered saline; 2) DPY; 3) INDP + DPY; 4) DPY+ FG; 5) INDP + DPY + FG + MSCs. In all rats, intervention was performed 72 hours after spinal cord injury. Locomotor and sensibility recovery was assessed in all rats. At 60 days after treatment, histological examinations of the spinal cord (hematoxylin-eosin and Bielschowsky staining) were performed. Our results showed that the combination therapy (DPY+ INDP + FG + MSCs) was the best strategy to promote motor and sensibility recovery. In addition, significant increases in tissue preservation and axonal density were observed in the combination therapy group. Findings from this study suggest that the combination theapy (DPY+ INDP + FG + MSCs) exhibits potential effects on the protection and regeneration of neural tissue after acute spinal cord injury. All procedures were approved by the Animal Bioethics and Welfare Committee (approval No. 178544; CSNBTBIBAJ 090812960) on August 15, 2016.

Potentially Common Therapeutic Targets for Multiple Sclerosis and Ischemic Stroke

Ischemic stroke (IS) and multiple sclerosis (MS) are two pathologies of the central nervous system (CNS). At the first look, this appears to be the only similarity between the two diseases, as they seem quite different. Indeed IS has an acute onset compared to MS which develops chronically; IS is consecutive to blood clot migrating to cerebral blood vessels or decrease in cerebral blood flow following atherosclerosis or decreases in cardiac output, whereas MS is an immune disease associated with neurodegeneration. However, both pathologies share similar pathologic pathways and treatments used in MS have been the object of studies in IS. In this mini-review we will discuss similarities between IS and MS on astrocytes and neuroinflammation hallmarks emphasizing the potential for treatments.

Pharmacological approaches promoting stem cell-based therapy following ischemic stroke insults

Stroke can lead to long-term neurological deficits. Adult neurogenesis, the continuous generation of newborn neurons in distinct regions of the brain throughout life, has been considered as one of the appoaches to restore the neurological function following ischemic stroke. However, ischemia-induced spontaneous neurogenesis is not suffcient, thus cell-based therapy, including infusing exogenous stem cells or stimulating endogenous stem cells to help repair of injured brain, has been studied in numerous animal experiments and some pilot clinical trials. While the effects of cell-based therapy on neurological function during recovery remains unproven in randomized controlled trials, pharmacological agents have been administrated to assist the cell-based therapy. In this review, we summarized the limitations of ischemia-induced neurogenesis and stem-cell transplantation, as well as the potential proneuroregenerative effects of drugs that may enhance efficacy of cell-based therapies. Specifically, we discussed drugs that enhance proliferation, migration, differentiation, survival and function connectivity of newborn neurons, which may restore neurobehavioral function and improve outcomes in stroke patients.

Immunotherapy of experimental and human stroke with agents approved for multiple sclerosis: a systematic review

Background

'Thromboinflammation' describes a novel concept in stroke pathophysiology that has opened up the possibility of immunotherapeutic approaches which could become promising strategies for targeted stroke therapies in the future.

Methods

We reviewed current evidence for agents approved for multiple sclerosis in preclinical and clinical stroke studies. A systematic review was performed in accordance with the PRISMA statement, searching MEDLINE, the Cochrane Central Register of Controlled Trials, and reference lists of articles published until 16 October 2017.

Results

The review included 52 of 629 identified studies, consisting of 5 clinical and 47 preclinical trials. Most of the studies showed beneficial effects of the evaluated immunotherapeutic drugs in terms of reduction in morphological lesion size and improvement in functional outcome. Nevertheless, the significance of these findings is limited due to the high degree of heterogeneity.

Conclusions

Immunotherapy of stroke might be effective and could become a promising treatment strategy, but larger clinical trials with standardized interventions and outcome measures are needed.

Copolymer-1 enhances cognitive performance in young adult rats

Cognitive impairment is a dysfunction observed as a sequel of various neurodegenerative diseases, as well as a concomitant element in the elderly stages of life. In clinical settings, this malfunction is identified as mild cognitive impairment. Previous studies have suggested that cognitive impairment could be the result of a reduction in the expression of brain-derived neurotrophic factor (BDNF) and/or immune dysfunction. Copolymer-1 (Cop-1) is an FDA-approved synthetic peptide capable of inducing the activation of Th2/3 cells, which are able to release BDNF, as well as to migrate and accumulate in the brain. In this study, we evaluated the effect of Cop-1 immunization on improvement of cognition in adult rats. For this purpose, we performed four experiments. We evaluated the effect of Cop-1 immunization on learning/memory using the Morris water maze for spatial memory and autoshaping for associative memory in 3- or 6-month-old rats. BDNF concentrations at the hippocampus were determined by ELISA. Cop-1 immunization induced a significant improvement of spatial memory and associative memory in 6-month-old rats. Likewise, Cop-1 improved spatial memory and associative memory when animals were immunized at 3 months and evaluated at 6 months old. Additionally, Cop-1 induced a significant increase in BDNF levels at the hippocampus. To our knowledge, the present investigation reports the first instance of Cop-1 treatment enhancing cognitive function in normal young adult rats, suggesting that Cop-1 may be a practical therapeutic strategy potentially useful for age- or disease-related cognitive impairment.

Release of interleukin-10 and neurotrophic factors in the choroid plexus: possible inductors of neurogenesis following copolymer-1 immunization after cerebral ischemia

Copolymer-1 (Cop-1) is a peptide with immunomodulatory properties, approved by the Food and Drug Administration of United States in the treatment of multiple sclerosis. Cop-1 has been shown to exert neuroprotective effects and induce neurogenesis in cerebral ischemia models. Nevertheless, the mechanism involved in the neurogenic action of this compound remains unknown. The choroid plexus (CP) is a network of cells that constitute the interphase between the immune and central nervous systems, with the ability to mediate neurogenesis through the release of cytokines and growth factors. Therefore, the CP could play a role in Cop-1-induced neurogenesis. In order to determine the participation of the CP in the induction of neurogenesis after Cop-1 immunization, we evaluated the gene expression of various growth factors (brain-derived neurotrophic factor, insulin-like growth factor 1, neurotrophin-3) and cytokines (tumor necrosis factor alpha, interferon-gamma, interleukin-4 (IL-4), IL-10 and IL-17), in the CP at 14 days after ischemia. Furthermore, we analyzed the correlation between the expression of these genes and neurogenesis. Our results showed that Cop-1 was capable of stimulating an upregulation in the expression of the genes encoding for brain-derived neurotrophic factor, insulin-like growth factor 1, neurotrophin-3 and IL-10 in the CP, which correlated with an increase in neurogenesis in the subventricular and subgranular zone. As well, we observed a downregulation of IL-17 gene expression. This study demonstrates the effect of Cop-1 on the expression of growth factors and IL-10 in the CP, in the same way, presents a possible mechanism involved in the neurogenic effect of Cop-1.

Immunization with neural derived peptides plus scar removal induces a permissive microenvironment, and improves locomotor recovery after chronic spinal cord injury

Background

Immunization with neural derived peptides (INDP) as well as scar removal—separately—have shown to induce morphological and functional improvement after spinal cord injury (SCI). In the present study, we compared the effect of INDP alone versus INDP with scar removal on motor recovery, regeneration-associated and cytokine gene expression, and axonal regeneration after chronic SCI. Scar removal was conducted through a single incision with a double-bladed scalpel along the stump, and scar renewal was halted by adding α,α′-dipyridyl.

Results

During the chronic injury stage, two experiments were undertaken. The first experiment was aimed at testing the therapeutic effect of INDP combined with scar removal. Sixty days after therapeutic intervention, the expression of genes encoding for TNFα, IFNγ, IL4, TGFβ, BDNF, IGF1, and GAP43 was evaluated at the site of injury. Tyrosine hydroxylase and 5-hydroxytryptamine positive fibers were also studied. Locomotor evaluations showed a significant recovery in the group treated with scar removal + INDP. Moreover; this group presented a significant increase in IL4, TGFβ, BDNF, IGF1, and GAP43 expression, but a decrease of TNFα and IFNγ. Also, the spinal cord of animals receiving both treatments presented a significant increase of serotonergic and catecholaminergic fibers as compared to other the groups. The second experiment compared the results of the combined approach versus INDP alone. Rats receiving INDP likewise showed improved motor recovery, although on a lesser scale than those who received the combined treatment. An increase in inflammation and regeneration-associated gene expression, as well as in the percentage of serotonergic and catecholaminergic fibers was observed in INDP-treated rats to a lesser degree than those in the combined therapy group.

Conclusions

These findings suggest that INDP, both alone and in combination with scar removal, could modify the non-permissive microenvironment prevailing at the chronic phase of SCI, providing the opportunity of improving motor recovery.