Resolution of stroke deficits following contralateral grafts of conditionally immortal neuroepithelial stem cells

Targeting MAD2B as a strategy for ischemic stroke therapy

INTRODUCTION

Post-stroke cognitive impairment is one of the major causes of disability due to cerebral ischemia. MAD2B is an inhibitor of Cdh1/APC, and loss of Cdh1/APC function in mature neurons increases ROCK2 activity, leading to changes in synaptic plasticity and memory loss in mouse neurons. Whether MAD2B regulates learning memory capacity through ROCK2 in cerebral ischemia is not known.

OBJECTIVES

We investigated the role and mechanism of MAD2B in cerebral ischemia-induced cognitive dysfunction.

METHODS

The expression of MAD2B and its downstream related molecules was detected by immunoblotting and intervened with neuroprotectants after middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R). We constructed MAD2B-cKO-specific knockout mice, knocked down and overexpressed MAD2B in mouse hippocampus by lentiviral injection in brain stereotaxis, modeled cerebral ischemia by using MCAO, and explored the role of MAD2B in post-stroke cognitive impairment (PSCI) by animal behaviors such as Y-maze and Novel object recognition test. Then the expression of MAD2B/ROCK2, downstream molecules and apoptosis-related molecules was detected. Finally, ROCK2 expression was intervened using its inhibitor and shRNA-ROCK2 lentivirus.

RESULTS

The expression of MAD2B and its downstream molecules increased after MCAO and OGD/R. Nonetheless, this expression underwent a decline post-therapy with neuroprotective agents. Deletion of MAD2B in the hippocampus ameliorated memory and learning deficits and improved motor coordination in MCAO mice. Conversely, the overexpression of MAD2B in the hippocampus exacerbated learning and memory deficits. Deletion of MAD2B resulted in the downregulation of ROCK2/LIMK1/cofilin. It effectively reduced ischemia-induced upregulation of BAX and cleaved caspase-3, which could be reversed by MAD2B overexpression. Inhibition or knockdown of ROCK2 expression in primary cultured neurons led to the downregulation of LIMK1/cofilin expression and reduced the expression of apoptosis-associated molecules induced by ischemia.

CONCLUSIONS

Our findings suggest that MAD2B affects neuronal apoptosis via Rock2, which affects neurological function and cerebral infarction.

Transgenic rat with overproduction of ubiquitous angiotensin-(1-7) presents neuroprotection in a model of ischemia and reperfusion

Recent studies showed that angiotensin-(1-7) has cerebroprotective actions in stroke. In the present study, we aim to test whether tissue overexpression of Angiotensin-(1-7), mainly in the brain provides neuroprotection in a model of ischemia/reperfusion by bilateral common carotid arteries occlusion/reperfusion (BCCAo/R). Evaluation of neurological deficit scores and bilateral asymmetry test (BAT) were performed seven days after transient BCCAo/R in transgenic rats (TG-7371) overexpressing Angiotensin-(1-7) and Sprague-Dawley (SD) rats. To assess blood-brain barrier (BBB) permeability Evans blue dye (EB) was intravenously injected. Cytokine levels were quantified in the whole brain through Elisa assay and oxidative stress was measured 7 days after ischemia. The expression of AT₁ and Mas receptors and inducible nitric oxide synthase (iNOS) was evaluated by RT-PCR. Neurological deficits were observed in both SD-BCCAo/R and TG-BCCAo/R, contrasting to sham-operated groups. However, TG-BCCAo/R showed a significant lower neurological score and latency in BAT when compared with SD-BCCAo/R. BBB integrity in TG-BCCAo/R was improved, since these animals showed lower extravasation of EB than SD-BCCAo/R. Interestingly, TG-BCCAo/R presented lower levels of pro-inflammatory cytokines when compared to SD-BCCAo/R. Levels of IL-10 were higher in SD-BCCAo/R than in SD control and even higher in TG-BCCAo/R. TG-BCCAo/R animals presented decreased levels of TBARS and increase in SOD activity and GSH levels when compared to SD sham rats. RT-PCR results showed higher levels of AT₁ receptor and iNOS in SD-BCCAo/R compared to TG-BCCAo/R, but no difference was observed for Mas receptor. The present study shows that lifetime increase in cerebral expression of an Ang-(1-7)-producing fusion protein induces neuroprotection in experimental global cerebral ischemia and reperfusion, reassuring that, pharmacological strategies leading to increase in Ang-(1-7) can be an additional tool for stroke therapy.

Stem Cell Transplantation Therapy and Neurological Disorders: Current Status and Future Perspectives

Neurodegenerative diseases are a global health issue with inadequate therapeutic options and an inability to restore the damaged nervous system. With advances in technology, health scientists continue to identify new approaches to the treatment of neurodegenerative diseases. Lost or injured neurons and glial cells can lead to the development of several neurological diseases, including Parkinson's disease, stroke, and multiple sclerosis. In recent years, neurons and glial cells have successfully been generated from stem cells in the laboratory utilizing cell culture technologies, fueling efforts to develop stem cell-based transplantation therapies for human patients. When a stem cell divides, each new cell has the potential to either remain a stem cell or differentiate into a germ cell with specialized characteristics, such as muscle cells, red blood cells, or brain cells. Although several obstacles remain before stem cells can be used for clinical applications, including some potential disadvantages that must be overcome, this cellular development represents a potential pathway through which patients may eventually achieve the ability to live more normal lives. In this review, we summarize the stem cell-based therapies that have been explored for various neurological disorders, discuss the potential advantages and drawbacks of these therapies, and examine future directions for this field.

Long-Term Clinical Efficacy of Human Umbilical Cord Blood Mononuclear Cell Transplantation by Lateral Atlanto-Occipital Space Puncture (Gong's Puncture) for the Treatment of Multiple System Atrophy

Multiple system atrophy (MSA) is a sporadic, progressive neurodegenerative disease characterized by autonomic nervous dysfunction with parkinsonism or cerebellar ataxia. Mesenchymal stem cell therapy or transplantation of human umbilical cord blood mononuclear cells (hUCB-MCs) may inhibit progression in MSA, but long-term studies are lacking. In addition, injection of stem cells via lateral atlanto-occipital space puncture (LASP, or Gong's puncture) may efficiently target areas of brain injury and avoid the disadvantages of other methods. This prospective study investigated the long-term clinical efficacy of transplantation of hUCB-MCs via LASP for the treatment of MSA. Seven patients with MSA who received hUCB-MC transplantation via LASP were followed for 3 to 5 years. Neurological function was evaluated before (baseline), at 3, 6, and 12 months, and annually after the first transplantation using the Unified MSA Rating Scale (UMSARS); a lower score indicated improvement. Adverse events were recorded. The best therapeutic effect was observed 3 to 6 months after the first hUCB-MC transplantation. The total UMSARS score at the timepoint of best effect (25.71 ± 11.87) was significantly lower than the score before treatment (42.57 ± 7.96; P = 0.001), but also significantly lower than at the end of follow-up (35.14 ± 18.21; P = 0.038). The UMSARS II score (findings on neurological examination) at the timepoint of best effect was significantly lower than before treatment (P = 0.001). There were no serious adverse events. In conclusion, transplantation of hUCB-MCs via LASP is a safe and effective treatment for MSA.

Stem Cell-Based Therapy for Experimental Ischemic Stroke: A Preclinical Systematic Review

Stem cell transplantation offers promise in the treatment of ischemic stroke. Here we utilized systematic review, meta-analysis, and meta-regression to study the biological effect of stem cell treatments in animal models of ischemic stroke. A total of 98 eligible publications were included by searching PubMed, EMBASE, and Web of Science from inception to August 1, 2020. There are about 141 comparisons, involving 5,200 animals, that examined the effect of stem cell transplantation on neurological function and infarct volume as primary outcome measures in animal models for stroke. Stem cell-based therapy can improve both neurological function (effect size, −3.37; 95% confidence interval, −3.83 to −2.90) and infarct volume (effect size, −11.37; 95% confidence interval, −12.89 to −9.85) compared with controls. These results suggest that stem cell therapy could improve neurological function deficits and infarct volume, exerting potential neuroprotective effect for experimental ischemic stroke, but further clinical studies are still needed.

Revisiting Stem Cell-Based Clinical Trials for Ischemic Stroke

Stroke is the leading cause of serious long-term disability, significantly reducing mobility in almost half of the affected patients aged 65 years and older. There are currently no proven neurorestorative treatments for chronic stroke. To address the complex problem of restoring function in ischemic brain tissue, stem cell transplantation-based therapies have emerged as potential restorative therapies. Aligning with the major cell types found within the ischemic brain, stem-cell-based clinical trials for ischemic stroke have fallen under three broad cell lineages: hematopoietic, mesenchymal, and neural. In this review article, we will discuss the scientific rationale for transplanting cells from each of these lineages and provide an overview of published and ongoing trials using this framework.

Multimodal Therapeutic Effects of Neural Precursor Cells Derived from Human-Induced Pluripotent Stem Cells through Episomal Plasmid-Based Reprogramming in a Rodent Model of Ischemic Stroke

Stem cell therapy is a promising option for treating functional deficits in the stroke-damaged brain. Induced pluripotent stem cells (iPSCs) are attractive sources for cell therapy as they can be efficiently differentiated into neural lineages. Episomal plasmids (EPs) containing reprogramming factors can induce nonviral, integration-free iPSCs. Thus, iPSCs generated by an EP-based reprogramming technique (ep-iPSCs) have an advantage over gene-integrating iPSCs for clinical applications. However, there are few studies regarding the in vivo efficacy of ep-iPSCs. In this study, we investigated the therapeutic potential of intracerebral transplantation of neural precursor cells differentiated from ep-iPSCs (ep-iPSC-NPCs) in a rodent stroke model. The ep-iPSC-NPCs were transplanted intracerebrally in a peri-infarct area in a rodent stroke model. Rats transplanted with fibroblasts and vehicle were used as controls. The ep-iPSC-NPC-transplanted animals exhibited functional improvements in behavioral and electrophysiological tests. A small proportion of ep-iPSC-NPCs were detected up to 12 weeks after transplantation and were differentiated into both neuronal and glial lineages. In addition, transplanted cells promoted endogenous brain repair, presumably via increased subventricular zone neurogenesis, and reduced poststroke inflammation and glial scar formation. Taken together, these results strongly suggest that intracerebral transplantation of ep-iPSC-NPCs is a useful therapeutic option to treat clinical stroke through multimodal therapeutic mechanisms.

Drug-like delivery methods of stem cells as biologics for stroke

Introduction: Stem cell therapy is an experimental treatment for brain disorders. Although a cellular product, stem cells can be classified as biologics based on the cells' secretion of therapeutic substances. Treatment with stem cell biologics may appeal to stroke because of the secondary cell death mechanisms, especially neuroinflammation, that are rampant from the onset and remain elevated during the progressive phase of the disease requiring multi-pronged biological targets to effectively abrogate the neurodegenerative pathology. However, the optimal delivery methods, among other logistical approaches (i.e. cell doses and timing of intervention), for stem cell therapy will need to be refined before stem cell biologics can be successfully utilized for stroke in large scale clinical trials. Areas covered: In this review, we discuss how the innate qualities of stem cells characterize them as biologics, how stem cell transplantation may be an ideal treatment for stroke, and the various routes of stem cell administration that have been employed in various preclinical and clinical investigations. Expert opinion: There is a need to optimize the delivery of stem cell biologics for stroke in order to guide the safe and effective translation of this therapy from the laboratory to the clinic.

Stem Cell Therapy: A Promising Therapeutic Method for Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is one type of the most devastating cerebrovascular diseases worldwide, which causes high morbidity and mortality. However, efficient treatment is still lacking. Stem cell therapy has shown good neuroprotective and neurorestorative effect in ICH and is a promising treatment. In this study, our aim was to review the therapeutic effects, strategies, related mechanisms and safety issues of various types of stem cell for ICH treatment. Numerous studies had demonstrated the therapeutic effects of diverse stem cell types in ICH. The potential mechanisms include tissue repair and replacement, neurotrophy, promotion of neurogenesis and angiogenesis, anti-apoptosis, immunoregulation and anti-inflammation and so forth. The microenvironment of the central nervous system (CNS) can also influence the effects of stem cell therapy. The detailed therapeutic strategies for ICH treatment such as cell type, the number of cells, time window, and the routes of medication delivery, varied greatly among different studies and had not been determined. Moreover, the safety issues of stem cell therapy for ICH should not be ignored. Stem cell therapy showed good therapeutic effect in ICH, making it a promising treatment. However, safety should be carefully evaluated, and more clinical trials are required before stem cell therapy can be extensively applied to clinical use.

Getting Closer to an Effective Intervention of Ischemic Stroke: The Big Promise of Stem Cell

Stem cell therapy for ischemic stroke has widely been explored. Results from both preclinical and clinical studies have immensely supported the judicious use of stem cells as therapy. These provide an attractive means for preserving and replacing the damaged brain tissues following an ischemic attack. Since the past few years, researchers have used various types of stem cells to replenish insulted neuronal and glial cells in neurological disorders. In the present review, we discuss different types of stem cells employed for the treatment of ischemic stroke and mechanisms and challenges these cells face once introduced into the living system. Further, we also present different ways to maneuver and overcome challenges to translate the advances made at the preclinical level to clinics.

Stem cell transplantation therapy for multifaceted therapeutic benefits after stroke

One of the exciting advances in modern medicine and life science is cell-based neurovascular regeneration of damaged brain tissues and repair of neuronal structures. The progress in stem cell biology and creation of adult induced pluripotent stem (iPS) cells has significantly improved basic and pre-clinical research in disease mechanisms and generated enthusiasm for potential applications in the treatment of central nervous system (CNS) diseases including stroke. Endogenous neural stem cells and cultured stem cells are capable of self-renewal and give rise to virtually all types of cells essential for the makeup of neuronal structures. Meanwhile, stem cells and neural progenitor cells are well-known for their potential for trophic support after transplantation into the ischemic brain. Thus, stem cell-based therapies provide an attractive future for protecting and repairing damaged brain tissues after injury and in various disease states. Moreover, basic research on naïve and differentiated stem cells including iPS cells has markedly improved our understanding of cellular and molecular mechanisms of neurological disorders, and provides a platform for the discovery of novel drug targets. The latest advances indicate that combinatorial approaches using cell based therapy with additional treatments such as protective reagents, preconditioning strategies and rehabilitation therapy can significantly improve therapeutic benefits. In this review, we will discuss the characteristics of cell therapy in different ischemic models and the application of stem cells and progenitor cells as regenerative medicine for the treatment of stroke.

Transplanted Human Neural Precursor Cells Migrate Widely but Show no Lesion-Specific Tropism in the 6-Hydroxydopamine Rat Model of Parkinson's Disease

Parkinson's disease (PD), while primarily associated with degeneration of nigrostriatal dopamine neurons, is now increasingly recognized to have more widespread cell loss and so the most effective cell replacement therapy should target all these neuronal losses. Neural precursor cells might be ideal in this regard as in certain circumstances they have been shown to migrate widely following transplantation into the CNS. The aim of this study was to investigate whether transplanted human expanded neural precursor cells (hENPs) could migrate to sites of established or evolving pathology in the adult brain using the 6-hydroxydopamine (6-OHDA) rat model of PD. hENPs were grafted into the striatum prior to, at the same time as, or after the animals received a 6-OHDA lesion to the medial forebrain bundle. The presence of donor cells was then assessed in a distant site of cell loss (substantia nigra) or sites where cell death would not be expected (frontal cortex and globus pallidus). Donor cells were found distant from the site of implantation but the migration of these hENPs was not significantly greater in the 6-OHDA-lesioned brain and the cells did not specifically target the site of cell loss in the substantia nigra. The temporal relationship of grafting relative to the lesion, and therefore dopaminergic cell death, did not affect the migration of hENPs nor their differentiation. We conclude that while transplanted hENPs are capable of migration away from the site of implantation, they show no specific tropism for sites of ongoing or established nigral dopaminergic cell loss in this lesion model. Therefore, the use of such cells to replace the range of neurons lost in PD is likely to require a deeper understanding of the migratory cues in the damaged adult brain and some manipulation of these cells prior to transplantation.

Making Stem Cell Lines Suitable for Transplantation

Human stem cells, progenitor cells, and cell lines have been derived from embryonic, fetal, and adult sources in the search for graft tissue suitable for the treatment of CNS disorders. An increasing number of experimental studies have shown that grafts from several sources survive, differentiate into distinct cell types, and exert positive functional effects in experimental animal models, but little attention has been given to developing cells under conditions of good manufacturing practice (GMP) that can be scaled up for mass treatment. The capacity for continued division of stem cells in culture offers the opportunity to expand their production to meet the widespread clinical demands posed by neurodegenerative diseases. However, maintaining stem cell division in culture long term, while ensuring differentiation after transplantation, requires genetic and/or oncogenetic manipulations, which may affect the genetic stability and in vivo survival of cells. This review outlines the stages, selection criteria, problems, and ultimately the successes arising in the development of conditionally immortal clinical grade stem cell lines, which divide in vitro, differentiate in vivo, and exert positive functional effects. These processes are specifically exemplified by the murine MHP36 cell line, conditionally immortalized by a temperature-sensitive mutant of the SV40 large T antigen, and cell lines transfected with the c-myc protein fused with a mutated estrogen receptor (c-mycERTAM), regulated by a tamoxifen metabolite, but the issues raised are common to all routes for the development of effective clinical grade cells.

Evolution of ischemic damage and behavioural deficit over 6 months after MCAo in the rat: Selecting the optimal outcomes and statistical power for multi-centre preclinical trials

Key disparities between the timing and methods of assessment in animal stroke studies and clinical trial may be part of the reason for the failure to translate promising findings. This study investigates the development of ischemic damage after thread occlusion MCAo in the rat, using histological and behavioural outcomes. Using the adhesive removal test we investigate the longevity of behavioural deficit after ischemic stroke in rats, and examine the practicality of using such measures as the primary outcome for future studies. Ischemic stroke was induced in 132 Spontaneously Hypertensive Rats which were assessed for behavioural and histological deficits at 1, 3, 7, 14, 21, 28 days, 12 and 24 weeks (n>11 per timepoint). The basic behavioural score confirmed induction of stroke, with deficits specific to stroke animals. Within 7 days, these deficits resolved in 50% of animals. The adhesive removal test revealed contralateral neglect for up to 6 months following stroke. Sample size calculations to facilitate the use of this test as the primary experimental outcome resulted in cohort sizes much larger than are the norm for experimental studies. Histological damage progressed from a necrotic infarct to a hypercellular area that cleared to leave a fluid filled cavity. Whilst absolute volume of damage changed over time, when corrected for changes in hemispheric volume, an equivalent area of damage was lost at all timepoints. Using behavioural measures at chronic timepoints presents significant challenges to the basic science community in terms of the large number of animals required and the practicalities associated with this. Multicentre preclinical randomised controlled trials as advocated by the MultiPART consortium may be the only practical way to deal with this issue.

Ethical clinical translation of stem cell interventions for neurologic disease

The application of stem cell transplants in clinical practice has increased in frequency in recent years. Many of the stem cell transplants in neurologic diseases, including stroke, Parkinson disease, spinal cord injury, and demyelinating diseases, are unproven-they have not been tested in prospective, controlled clinical trials and have not become accepted therapies. Stem cell transplant procedures currently being carried out have therapeutic aims, but are frequently experimental and unregulated, and could potentially put patients at risk. In some cases, patients undergoing such operations are not included in a clinical trial, and do not provide genuinely informed consent. For these reasons and others, some current stem cell interventions for neurologic diseases are ethically dubious and could jeopardize progress in the field. We provide discussion points for the evaluation of new stem cell interventions for neurologic disease, based primarily on the new Guidelines for Stem Cell Research and Clinical Translation released by the International Society for Stem Cell Research in May 2016. Important considerations in the ethical translation of stem cells to clinical practice include regulatory oversight, conflicts of interest, data sharing, the nature of investigation (e.g., within vs outside of a clinical trial), informed consent, risk-benefit ratios, the therapeutic misconception, and patient vulnerability. To help guide the translation of stem cells from the laboratory into the neurosurgical clinic in an ethically sound manner, we present an ethical discussion of these major issues at stake in the field of stem cell clinical research for neurologic disease.

Stem Cell Therapy and Administration Routes After Stroke

Cell-based therapy has demonstrated safety and efficacy in experimental animal models of stroke, as well as safety in stroke patients. However, various questions remain regarding the therapeutic window, dosage, route of administration, and the most appropriate cell type and source, as well as mechanisms of action and immune-modulation to optimize treatment based on stem cell therapy. Various delivery routes have been used in experimental stroke models, including intracerebral, intraventricular, subarachnoid, intra-arterial, intraperitoneal, intravenous, and intranasal routes. From a clinical point of view, it is necessary to demonstrate which is the most feasible, safest, and most effective for use with stroke patients. Therefore, further experimental studies concerning the safety, efficacy, and mechanisms of action involved in these therapeutic effects are required to determine their optimal clinical use.

Efficacy of Surgery Combined with Autologous Bone Marrow Stromal Cell Transplantation for Treatment of Intracerebral Hemorrhage

Bone marrow stromal cells (BMSCs) may differentiate into nerve cells under a certain condition; however, the clinical application for treating nervous system disease remains unclear. The aim is to assess the safety profile, feasibility, and effectiveness of surgery combined with autologous BMSCs transplantation for treating ICH. 206 ICH patients who had received surgical procedure were divided into transplantation (n = 110) or control group (n = 96). For transplantation group, BMSCs were injected into the perihemorrhage area in the base ganglia through an intracranial drainage tube 5.5 (3.01–6.89) days after surgery, followed by a second injection into the subarachnoid space through lumbar puncture 4 weeks later. Neurologic impairment and daily activities were assessed with National Institute Stroke Scale (NIHSS), Barthel index, and Rankin scale before transplantation and 6 months and 12 months after transplantation. Our results revealed that, compared with control group, NIHSS score and Rankin scale were both significantly decreased but Barthel index was increased in transplantation group after 6 months. Interestingly, no significant difference was observed between 12 months and 6 months. No transplantation-related adverse effects were investigated during follow-up assessments. Our findings suggest that surgery combined with autologous BMSCs transplantation is safe for treatment of ICH, providing short-term therapeutic benefits.

Motor Recovery Strategies After Stroke

Impaired motor function after stroke is a major cause of disability in young stroke survivors. The plasticity of the adult human brain provides opportunities to enhance traditional rehabilitation programs for these individuals. Younger stroke patients appear to have a greater ability to recover from stroke and are likely to benefit substantially from treatments that facilitate plasticity-mediated recovery. The use of new exercise treatments, such as constraint-induced movement therapy, robot-aided rehabilitation, and partial body weight supported treadmill training are being studied intensively and are likely to ultimately be incorporated into standard poststroke rehabilitation. Medications to enhance recovery, growth factors, and stem cells will also be components of rehabilitation for the young stroke survivor in the foreseeable future.

Strategies for regeneration of components of nervous system: scaffolds, cells and biomolecules

Nerve diseases including acute injury such as peripheral nerve injury (PNI), spinal cord injury (SCI) and traumatic brain injury (TBI), and chronic disease like neurodegeneration disease can cause various function disorders of nervous system, such as those relating to memory and voluntary movement. These nerve diseases produce great burden for individual families and the society, for which a lot of efforts have been made. Axonal pathways represent a unidirectional and aligned architecture allowing systematic axonal development within the tissue. Following a traumatic injury, the intricate architecture suffers disruption leading to inhibition of growth and loss of guidance. Due to limited capacity of the body to regenerate axonal pathways, it is desirable to have biomimetic approach that has the capacity to graft a bridge across the lesion while providing optimal mechanical and biochemical cues for tissue regeneration. And for central nervous system injury, one more extra precondition is compulsory: creating a less inhibitory surrounding for axonal growth. Electrospinning is a cost-effective and straightforward technique to fabricate extracellular matrix (ECM)-like nanofibrous structures, with various fibrous forms such as random fibers, aligned fibers, 3D fibrous scaffold and core-shell fibers from a variety of polymers. The diversity and versatility of electrospinning technique, together with functionalizing cues such as neurotrophins, ECM-based proteins and conductive polymers, have gained considerable success for the nerve tissue applications. We are convinced that in the future the stem cell therapy with the support of functionalized electrospun nerve scaffolds could be a promising therapy to cure nerve diseases.

Coarse electrocorticographic decoding of ipsilateral reach in patients with brain lesions

In patients with unilateral upper limb paralysis from strokes and other brain lesions, strategies for functional recovery may eventually include brain-machine interfaces (BMIs) using control signals from residual sensorimotor systems in the damaged hemisphere. When voluntary movements of the contralateral limb are not possible due to brain pathology, initial training of such a BMI may require use of the unaffected ipsilateral limb. We conducted an offline investigation of the feasibility of decoding ipsilateral upper limb movements from electrocorticographic (ECoG) recordings in three patients with different lesions of sensorimotor systems associated with upper limb control. We found that the first principal component (PC) of unconstrained, naturalistic reaching movements of the upper limb could be decoded from ipsilateral ECoG using a linear model. ECoG signal features yielding the best decoding accuracy were different across subjects. Performance saturated with very few input features. Decoding performances of 0.77, 0.73, and 0.66 (median Pearson's r between the predicted and actual first PC of movement using nine signal features) were achieved in the three subjects. The performance achieved here with small numbers of electrodes and computationally simple decoding algorithms suggests that it may be possible to control a BMI using ECoG recorded from damaged sensorimotor brain systems.

How can you mend a broken brain? Neurorestorative approaches to stroke recovery

BACKGROUND

Stroke is a devastating disorder that strikes approximately 15 million people worldwide. While most patients survive stroke, many are left with lifelong impairments, thereby making stroke the leading cause of permanent neurological disability. Despite this, there are a few options for treatment of acute stroke. Restoration of blood flow using clot-dissolving drugs has produced impressive benefits in some patients. However, for these drugs to be effective, they must be given soon after stroke onset and relatively only a few stroke patients reach hospital within this time. Side effects of these compounds further limit their use.

SUMMARY

Enhancing the brain's endogenous capacity for reorganization and self-repair offers the most promise for victims of stroke. Indeed, many stroke patients show considerable spontaneous functional improvement. Findings in the last 15 years suggest that stroke and related injury create a cerebral milieu similar to that of early brain development, a period characterized by rapid neuronal growth and neuroplasticity. A variety of interventions (e.g., stem cells, delivery of growth factors) are currently being explored in order to enhance neuroplasticity and reorganizational processes that are important for recovery of function. An emerging concept is that combinational or 'cocktail' therapies are more effective than single interventions in improving stroke recovery. Among these, one of the most promising therapies is enriched rehabilitation, a combination of environmental enrichment and task-specific therapy (e.g., reach training).

KEY MESSAGES

Neurorestorative approaches to brain reorganization and repair are providing new insights into how neural circuits respond to injury and how this knowledge can be used for optimizing stroke rehabilitation practice.

Whole-scale neurobehavioral assessments of photothrombotic ischemia in freely moving mice

BACKGROUND

Neurobehavioral assessments have been considered as an essential component of preclinical research in ischemic stroke. However, real-time neurobehavioral evaluation is seldom applied during ischemia induction as it is usually accompanied with anesthesia.

NEW METHOD

We induced photothrombosis in freely moving mice after one-week recovery from cannula implantation surgeries. After rose bengal (RB) injection (100 mg/kg, i.p.), photothrombosis was induced in freely moving mice by 473 nm laser irradiation through the cannulas implanted into unilateral primary motor cortex beforehand. Mice received nimodipine (15 mg/kg, i.p.), a widely used anti-ischemic agent, or vehicle before irradiation. Motor coordination and equilibrium were evaluated by rotarod and rung walk tests throughout the whole process of ischemia. Endurance capacity was assessed by treadmill at 1 day and 7 days after irradiation. Mice were decapitated at different time points post irradiation for TTC (2,3,5-triphenyltetrazolium chloride) staining.

RESULTS

Consistent with the results of TTC staining, motor deficits firstly occurred at 15-min post irradiation and aggravated 1-day later, while the capacity improved 3-days later and partially recovered 7-days post irradiation. And, the recovery process was accelerated by nimodipine application.

COMPARISON WITH EXISTING METHODS

This method established a precise linkage between focal brain ischemia development and neurobehavioral deficits throughout a full scale of photothrombosis, which avoided the confounding factors of anesthetics and surgeries on neurobehavioral assessments, as infarct was induced in freely moving mice.

CONCLUSIONS

This method with high temporal and spatial resolution will be an optimal model for neurobehavioral evaluation in preclinical anti-ischemic drug screening.

In vivo animal stroke models: a rationale for rodent and non-human primate models

On average, every four minutes an individual dies from a stroke, accounting for 1 out of every 18 deaths in the United States. Approximately 795,000 Americans have a new or recurrent stroke each year, with just over 600,000 of these being first attack [1]. There have been multiple animal models of stroke demonstrating that novel therapeutics can help improve the clinical outcome. However, these results have failed to show the same outcomes when tested in human clinical trials. This review will discuss the current in vivo animal models of stroke, advantages and limitations, and the rationale for employing these animal models to satisfy translational gating items for examination of neuroprotective, as well as neurorestorative strategies in stroke patients. An emphasis in the present discussion of therapeutics development is given to stem cell therapy for stroke.

Chronic metformin treatment improves post-stroke angiogenesis and recovery after experimental stroke

Metformin is currently the first-line treatment drug for type 2 diabetes. Metformin is a well-known activator of AMP-activated protein kinase (AMPK). In experimental studies, metformin has been shown to exert direct vascular effects by increasing vascular endothelial growth factor expression and improving microvascular density. As stroke is the leading cause of long-term disability and angiogenesis is implicated as an important mechanism in functional recovery, we hypothesized that chronic metformin treatment would improve post-stroke functional recovery by enhancing functional microvascular density. For this study, C57BL/6N male mice were subjected to a 60-min middle cerebral artery occlusion, and were given 50 mg/kg/day metformin beginning 24 h post-stroke for 3 weeks. Behavioral recovery was assessed using adhesive-tape removal and the apomorphine-induced turning test. The role of angiogenesis was assessed by counting vessel branch points from fluorescein-conjugated lectin-perfused brain sections. Importantly even if metformin treatment was initiated 24 h after injury it enhanced recovery and significantly improved stroke-induced behavioral deficits. This recovery occurred in parallel with enhanced angiogenesis and with restoration of endogenous cerebral dopaminergic tone and revascularization of ischemic tissue. We assessed if the effects on recovery and angiogenesis were mediated by AMPK. When tested in AMPK α-2 knockout mice, we found that metformin treatment did not have the same beneficial effects on recovery and angiogenesis, suggesting that metformin-induced angiogenic effects are mediated by AMPK. The results from this study suggest that metformin mediates post-stroke recovery by enhancing angiogenesis, and these effects are mediated by AMPK signaling.

Cell based therapies for ischemic stroke: from basic science to bedside

Cell therapy is emerging as a viable therapy to restore neurological function after stroke. Many types of stem/progenitor cells from different sources have been explored for their feasibility and efficacy for the treatment of stroke. Transplanted cells not only have the potential to replace the lost circuitry, but also produce growth and trophic factors, or stimulate the release of such factors from host brain cells, thereby enhancing endogenous brain repair processes. Although stem/progenitor cells have shown a promising role in ischemic stroke in experimental studies as well as initial clinical pilot studies, cellular therapy is still at an early stage in humans. Many critical issues need to be addressed including the therapeutic time window, cell type selection, delivery route, and in vivo monitoring of their migration pattern. This review attempts to provide a comprehensive synopsis of preclinical evidence and clinical experience of various donor cell types, their restorative mechanisms, delivery routes, imaging strategies, future prospects and challenges for translating cell therapies as a neurorestorative regimen in clinical applications.

Ischemia, immunosuppression, and SSEA-1-negative cells all contribute to tumors resulting from mouse embryonic stem cell-derived neural progenitor transplantation

Neural progenitor cells (NPCs) derived from mouse embryonic stem (mES) cells can lead to tumors after transplantation. The cellular source of such tumors remains under debate. We investigated the tumor formation resulting from mES cell-derived NPCs in a rat stroke model and in nude mice. After 2 hr of ischemia and 48 hr of reperfusion, the NPCs were transplanted into the ischemic core of the xenogeneic rats. Four weeks after transplantation, the grafted cells were found to be viable at the border of the necrosis and had differentiated into neurons. Transplanted rats did not exhibit any behavioral improvement, because tumor formed in 90% of the animals. Immunosuppression facilitated tumor formation. Tumors were observed in 40% of normal rats after NPC transplantation when cyclosporin A was administered. Meanwhile, no tumor formation was observed without cyclosporin A. Ischemic damage also facilitated tumor formation, because NPCs gave rise to tumors in 90% of ischemic rats, a percentage significantly higher than that in intact rats, which was 40%. The SSEA-1-positive cells isolated from stage 4 are not exactly undifferentiated ES cells. They exhibited a marker gene transcription profile different from that of ES cells and did not form tumors in transplanted nude mice. The undifferentiated ES cells remaining after differentiation did not contribute to tumors either. First, the tumor formation rate resulting from undifferentiated ES cells in the brains of normal rats is 0%, significantly lower than that of NPCs. Second, transplanted NPCs that led to 100% tumors in nude mice contained approximately 1.5 × 10(3) Oct-4-positive cells; however, even 5 × 10(5) undifferentiated ES cells formed neoplasm only in 40% nude mice.

Transplantation for stroke

Stroke is the most common cause of disability in the United States, and one of the leading causes of mortality and disability in the world. The hope that damage to the CNS can be reversed or at least ameliorated is the central idea behind the research into neural repair. The ultimate repair for the brain should restore the entire lost structure and it's function. However, partial benefit is possible from addressing some of the needs of the injured brain. These partial solutions are the basis of current research into brain repair after stroke. An opportunity arises for two kinds of intervention: (1) replacement of neurons; (2) support of existing neurons, to prevent excessive degeneration and promote rewiring and plasticity. Transplantation for stroke in the rat model was regularly reported starting in 1992, demonstrating graft survival and even evidence of connection with the host brain. These studies determined several parameters for future work in stroke models, but ultimately had limited efficacy and did not progress to clinical experiments. A variety of cell types have been tried for restoration of brain function after stroke, mostly in rodent models. Human fetal cells had shown some promise in clinical studies for the treatment of Parkinson's disease. The technical and ethical difficulties associated with these cells promoted a search for alternatives. These include porcine fetal cells, human cultured stem cells, immortalized cell lines, marrow stromal cells, Sertoli cells pineal cells, and other sources. Human clonal cell lines have few ethical limitations, but some questions remain regarding their safety and efficacy. Autologous somatic stem cells are a very attractive source--there are no ethical concerns and graft rejection is not an issue. However, it is not clear that somatic cells can are plastic enough and can be safely induced to a neural fate. Restorative treatment for stroke is a new field of study. Naturally, new ideas abound and many strategies have been suggested and tried. Methods and controversies abound, and include: local delivery of cells to the area of the stroke versus grafting to an area of the brain far removed form the stroke; cell therapy for reconstitution of structure and function versus use of cell grafts to support intrinsic repair and recovery mechanisms; intravascular administration of bone marrow or other stem cells; and combination grafts, or co-grafting of several cell types or cells and other substances. The various strategies address the issue of restorative treatments form different perspectives. Some interventions occur early after stroke, or are intended to preserve existing neural structures. For example, treatment strategies that aim to provide trophic support may demonstrate early beneficial results. Other strategies aim for growth and integration of new neurons to replace those lost after stroke. In this case, early beneficial results are not likely. Functional integration of grafted neurons, if it can ever happen, is likely to require training and exercise of the appropriate capacities. Further advances in preclinical studies of neural transplantation will require improved animal models with increased sensitivity to subtle behavioral and imaging changes. Non-human primate models have been established and may increase in importance as a phase before clinical trials. The future of brain repair for stroke is likely to require some form of combination therapy designed to replace the lost cells and supporting structure, attract new blood supply, support and enhance intrinsic repair and plasticity mechanisms.

Human induced pluripotent stem cell-derived neural stem cells survive, migrate, differentiate, and improve neurologic function in a rat model of middle cerebral artery occlusion

Introduction

Stroke is a major cause of permanent neurologic damage, with few effective treatments available to restore lost function. Induced pluripotent stem cells (iPSCs) have the potential to generate all cell types in vitro and can be generated from a stroke patient. Therefore, iPSCs are attractive donor sources of genetically identical “patient-specific” cells to hold promise in therapy for stroke. In the present study, we established a four-stage culture system by using serum-free medium and retinoic acid (RA) to differentiate iPSCs into neural stem cells (NSCs) effectively and stably. Our hypothesis was that iPSC-derived NSCs would survive, migrate, and differentiate in vivo, and improve neurologic function after transplantation into the brains of rats with ischemic stroke.

Methods

Human iPSCs (iPS-S-01) and human ESCs (HuES17) were used to differentiate into NSCs by using our four-stage culture system. iPSCs and differentiated NSCs were characterized by immunocytochemistry staining and reverse transcription-polymerase chain reaction (RT-PCR) analysis. After establishment of focal cerebral ischemia with occlusion of the middle cerebral artery (MCA) and cell transplantation, animals were killed at 1 week and 2 weeks to analyze survival, migration, and differentiation of implanted cells in brain tissue. Animal behavior was evaluated via rope grabbing, beam walking, and Morris water maze tests.

Results

iPSCs were efficiently induced into NSCs by using a newly established four-stage induction system in vitro. iPSCs expressed pluripotency-associated genes Oct4, Sox2, and Nanog before NSC differentiation. The iPSC-derived NSCs spontaneously differentiated into neurons and astrocytes, which highly express β-tubulin and glial fibrillary acidic protein (GFAP), respectively. On transplantation into the striatum, CM-DiI labeled iPSC-derived NSCs were found to migrate into the ischemia area at 1 week and 2 weeks, and animal-function recovery was significantly improved in comparison with control groups at 3 weeks.

Conclusions

The four-stage induction system is stable and effective to culture, differentiate, and induce iPSCs to NSCs by using serum-free medium combined with retinoic acid (RA). Implanted iPSC-derived NSCs were able to survive, migrate into the ischemic brain area to differentiate into mature neural cells, and seem to have potential to restore lost neurologic function from damage due to stroke in a rat model.

[Cell therapy for stroke: from myth to reality]

INTRODUCTION

Stroke is one of the leading causes of death and disability worldwide. Intravenous recombinant tissue plasminogen activator is the only available therapy for acute ischemic stroke, but its use is limited by a narrow therapeutic window and cannot stimulate endogenous repair and regeneration of damaged brain tissue. Stem cell-based approaches hold much promise as potential novel treatments to restore neurological function after stroke.

STATE OF THE ART

In this review, we summarize data from preclinical and clinical studies to investigate the potential application of stem cell therapies for treatment of stroke. Stem cells have been proposed as a potential source of new cells to replace those lost due to central nervous system injury, as well as a source of trophic molecules to minimize damage and promote recovery. Various stem cells from multiple sources can generate neural cells that survive and form synaptic connections after transplantation in the stroke-injured brain. Stem cells also exhibit neurorevitalizing properties that may ameliorate neurological deficits through stimulation of neurogenesis, angiogenesis and inhibition of inflammation.

PERSPECTIVES/CONCLUSION

Performed in stroke, cell therapy would decrease brain damage and reduce functional deficits. After the damage has been done, it would still improve neurological functions by activating endogenous repair. Nevertheless, many questions raised by experimental studies particularly related to long-term safety and technical details of cell preparation and administration must be resolved before wider clinical use.

Cellular replacement and regenerative medicine therapies in ischemic stroke

Worldwide, tissue engineering and cellular replacement therapies are at the forefront of the regenerative medicine agenda, and researchers are addressing key diseases, including diabetes, stroke and neurological disorders. It is becoming evident that neurological cell therapy is a necessarily complex endeavor. The brain as a cellular environment is complex, with diverse cell populations, including specialized neurons (e.g., dopaminergic, motor and glutamatergic neurons), each with specific functions. The population also contains glial cells (astrocytes and oligodendrocytes) that offer the supportive network for neuronal function. Neurological disorders have wide and varied pathologies; they can affect predominantly one cell type or a multitude of cell types, which is the case for ischemic stroke. Both neuronal and glial cells are affected by stroke and, depending on the region of the brain affected, different specialized cells are influenced. This review will address currently available therapies and focus on the application and potential of cell replacement, including stem cells and immortalized cell line-derived neurons as regenerative therapies for ischemic stroke, addressing current advances and challenges ahead.

Stem Cells in Stroke Treatment: The Promise and the Challenges

Stroke, for some years now the neglected major indication in the pharmaceutical development cupboard, has recently become one of the hot areas for stem cell therapy development. This is driven by better understanding of potential therapeutic opportunities both in the acute and chronic phases and the launch of a series of new early phase clinical trials in a number of countries, driven by positive data in relevant animal models. In addition, the impetus for stem cell product development is motivated by patient demand, with thousands of victims seeking unproven treatments abroad. This article looks at the many challenges facing the development of a stem cell therapy for stroke. These range from product characterization and banking, through nonclinical safety and efficacy to the regulatory requirements for starting patient trials and beyond to maximizing value from carefully designed efficacy trials.

Transplanted bone marrow mesenchymal stem cells improve memory in rat models of Alzheimer's disease

The present study aims to evaluate the effect of bone marrow mesenchymal stem cells (MSCs) grafts on cognition deficit in chemically and age-induced Alzheimer's models of rats. In the first experiments aged animals (30 months) were tested in Morris water maze (MWM) and divided into two groups: impaired memory and unimpaired memory. Impaired groups were divided into two groups and cannulated bilaterally at the CA1 of the hippocampus for delivery of mesenchymal stem cells (500 × 10(3)/μL) and PBS (phosphate buffer saline). In the second experiment, Ibotenic acid (Ibo) was injected bilaterally into the nucleus basalis magnocellularis (NBM) of young rats (3 months) and animals were tested in MWM. Then, animals with memory impairment received the following treatments: MSCs (500 × 10(3)/μL) and PBS. Two months after the treatments, cognitive recovery was assessed by MWM in relearning paradigm in both experiments. Results showed that MSCs treatment significantly increased learning ability and memory in both age- and Ibo-induced memory impairment. Adult bone marrow mesenchymal stem cells show promise in treating cognitive decline associated with aging and NBM lesions.

Stem Cells for Neurovascular Repair in Stroke

Stem cells exert therapeutic effects against ischemic stroke via transplantation of exogenous stem cells or stimulation of endogenous stem cells within the neurogenic niches of subventricular zone and subgranular zone, or recruited from the bone marrow through peripheral circulation. In this paper, we review the different sources of stem cells that have been tested in animal models of stroke. In addition, we discuss specific mechanisms of action, in particular neurovascular repair by endothelial progenitor cells, as key translational research for advancing the clinical applications of stem cells for ischemic stroke.

Migration and fate of therapeutic stem cells in different brain disease models

Stem cells have a number of properties, which make them excellent candidates for the treatment of various neurologic disorders, the most important of which being their ability to migrate to and differentiate predictably at sites of pathology in the brain. The disease-directed migration and well-characterized differentiation patterns of stem cells may eventually provide a powerful tool for the treatment of both localized and diffuse disease processes within the human brain. A thorough understanding of the molecular mechanisms governing their migratory properties and their choice between different differentiation programs is essential if these cells are to be used therapeutically in humans. This review focuses on summarizing the migration and differentiation of therapeutic neural and mesenchymal stem cells in different disease models in the brain and also discusses the promise of these cells to eventually treat various forms of neurologic disease.

MRI stem cell tracking for therapy in experimental cerebral ischemia

Magnetic resonance has an established role in investigations on the evolution of stroke and the assessment of therapeutic strategies in experimental animals. Here we show that the technique has also an important place for the study of stem cell-mediated regenerative therapies after stroke. We review the literature by bridging from the methodological aspects of stem cell labeling via grafting and monitoring of cell dynamics after implantation into the brain all the way to MRI's role in analyzing the stem cell-mediated functional improvement. Thus, we have aimed at a view combining the focus on the monitoring of the cell activities with the aspect of lesion evolution while including also the essence of a potential functional improvement by the implantation of stem cells following stroke.

Conditionally immortalised neural stem cells promote functional recovery and brain plasticity after transient focal cerebral ischaemia in mice

Cell therapy has enormous potential to restore neurological function after stroke. The present study investigated effects of conditionally immortalised neural stem cells (ciNSCs), the Maudsley hippocampal murine neural stem cell line clone 36 (MHP36), on sensorimotor and histological outcome in mice subjected to transient middle cerebral artery occlusion (MCAO). Adult male C57BL/6 mice underwent MCAO by intraluminal thread or sham surgery and MHP36 cells or vehicle were implanted into ipsilateral cortex and caudate 2 days later. Functional recovery was assessed for 28 days using cylinder and ladder rung tests and tissue analysed for plasticity, differentiation and infarct size. MHP36-implanted animals showed accelerated and augmented functional recovery and an increase in neurons (MAP-2), synaptic plasticity (synaptophysin) and axonal projections (GAP-43) but no difference in astrocytes (GFAP), oligodendrocytes (CNPase), microglia (IBA-1) or lesion volumes when compared to vehicle group. This is the first study showing a potential functional benefit of the ciNSCs, MHP36, after focal MCAO in mice, which is probably mediated by promoting neuronal differentiation, synaptic plasticity and axonal projections and opens up opportunities for future exploitation of genetically altered mice for dissection of mechanisms of stem cell based therapy.

Recent Advances on the Possible Neuroprotective Activities of Epstein-Barr Virus Oncogene BARF1 Protein in Chronic Inflammatory Disorders of Central Nervous System

Multiple sclerosis and neurodegenerative diseases in which cells of the central nervous system (CNS) are lost or damaged are rapidly increasing in frequency, and there is neither effective treatment nor cure to impede or arrest their destructive course. The Epstein-Barr virus is a human gamma-herpesvirus that infects more than 90% of the human population worldwide and persisting for the lifetime of the host. It is associated with numerous epithelial cancers, principally undifferentiated nasopharyngeal carcinoma and gastric carcinoma. Individuals with a history of symptomatic primary EBV infection, called infectious mononucleosis, carry a moderately higher risk of developing multiple sclerosis (MS). It is not known how EBV infection potentially promotes autoimmunity and central nervous system (CNS) tissue damage in MS. Recently it has been found that EBV isolates from different geographic regions have highly conserved BARF1 epitopes. BARF1 protein has the neuroprotective and mitogenic activity, thus may be useful to combat and overcome neurodegenerative disease. BARF1 protein therapy can potentially be used to enhance the neuroprotective activities by combinational treatment with anti-inflammatory antagonists and neuroprotectors in neural disorders.

Behavioral outcome measures used for human neural stem cell transplantation in rat stroke models

Stroke is a leading cause of death and disability, leading to the development of various stroke models to test new treatments, most commonly in the rat. Human stroke trials focus on disability, related primarily to neurological deficits. To better model the clinical application of these treatments, many behavioral tests have been developed using the rat stroke model. We performed a systematic review of all the behavioral outcome measures used in published studies of human neural stem cell transplantation in rat stroke models. The reviewed tests include motor, sensory, cognitive, activity, and combination tests. For each test, we give a brief description, trace the origin of the test, and discuss test performance in the reviewed studies. We conclude that while many behavioral tests are available for this purpose, there does not appear to be consensus on an optimal testing strategy.

Stem cell sources for regenerative medicine: the immunological point of view

Stem cell transplantation consists in the introduction of stem cells or derived products in a diseased organism. Because of the differentiation properties of stem cells, the goal is to replace damaged cells or tissues. Numbers of stem cell were identified and isolated from embryos, fetuses, or adult organs, harboring different properties, and thus providing multiple strategies of regenerative medicine for different diseases. More recently, the artificial induction of stemness properties in adult somatic cells has proposed a new way to generate stem cells. One important concern of stem cell therapy is the possible risk that transplanted stem cells could be rejected by the recipient's immune system. Depending on their source, stem cell transplantation is associated with diverse immunological situations. If some sources allow autologous transplantation, others cannot bypass an allogeneic context between the donor and the recipient. This review summarizes all of the stem cell sources for regenerative medicine and the immunological questions associated to their use. Regarding the emerging strategies compatible with autologous transplantation, this article points notably the complexity of the choice between the immunological safety and the specific advantages of allogeneic stem cells.

Current therapies for the soluble lysosomal forms of neuronal ceroid lipofuscinosis

The NCLs (neuronal ceroid lipofuscinoses) are the most common inherited paediatric neurodegenerative disorder. Although genetically distinct, NCLs can be broadly divided into two categories: one in which the mutation results in a defect in a transmembrane protein, and the other where the defect lies in a soluble lysosomal enzyme. A number of therapeutic approaches are applicable to the soluble lysosomal forms of NCL based on the phenomenon of cross-correction, whereby the ubiquitously expressed mannose 6-phosphate/IGF (insulin-like growth factor) II receptor provides an avenue for endocytosis, trafficking and lysosomal processing of extracellularly delivered enzyme. The present review discusses therapeutic utilization of cross-correction by enzyme-replacement therapy, gene therapy and stem cell therapy for the NCLs, along with an overview of the recent progress in translating these treatments into the clinic.

Investigating the effects of adult neural stem cell transplantation by lumbar puncture in transient cerebral ischemia

Stem cells have the ability to self renew and are therefore a good source for cell therapy following ischemia. In this study, we transplanted adult rat neural stem cells (NSCs) by lumbar puncture (LP) to investigate whether these cells can migrate and differentiate into neurons or glial cells, thereby improving functional outcome in cerebral ischemia. Transient ischemia was induced in adult rats (n=16) for 1h. Three days after the induction of ischemia, NSCs obtained from the subventricular zone of adult rats were injected into ischemic animals (n=8) by LP at the level of L6-S1. Improved recovery of the coordination of movement on the 1st, 7th, 14th, 21st and 28th days after the injury was examined by the Rotarod test and compared with non-transplanted ischemic animals (n=8). The presence of NSCs in the brain tissue of the animals was examined by immunohistofluorscence and immunohistochemical techniques. The coordination of movement in ischemic animals that received neural stem cells was improved significantly (P<0.05) compared with untreated ischemic animals. Cells labeled with PKH26 were observed in the ischemic area of brain tissue sections. The alkaline phosphatase test and immunohistochemical techniques demonstrated a gathering of NSCs in the lateral ventricle. A number of cells which expressed neuronal and astrocytic cell markers had migrated from the lateral ventricle to the subjacent brain parenchyma. NSCs injected by LP were able to migrate to the ischemic tissue and differentiate into neural-like cells. These differentiated cells may have improved the coordination in movement in the ischemic animals injected with NSCs.