Intracisternal basic fibroblast growth factor enhances functional recovery and up-regulates the expression of a molecular marker of neuronal sprouting following focal cerebral infarction

Implementing neuronal plasticity in NeuroAIDS: the experience of brain-derived neurotrophic factor and other neurotrophic factors

Human immunodeficiency virus type-1 (HIV) causes mild or severe neurological problems, termed HIV-associated neurocognitive disorder (HAND), even when HIV patients receive antiretroviral therapy. Thus, novel adjunctive therapies are necessary to reduce or abolish the neurotoxic effect of HIV. However, new therapies require a better understanding of the molecular and cellular mechanisms of HIV-induced neurotoxicity. HAND subjects are characterized by being profoundly depressed, and they experience deficits in memory, learning and movements. Experimental evidence has also shown that HIV reduces neurogenesis. These deficits resemble those occurring in premature brain aging or in a brain with impaired neural repair properties. Thus, it appears that HIV diminishes neuronal survival, along with reduced neuronal connections. These two phenomena should not occur in the adult and developing brain when synaptic plasticity is promoted by neurotrophic factors, polypeptides that are present in adult synapses. This review will outline experimental evidence as well as present emerging concepts for the use of neurotrophic factors and in particular brain-derived neurotrophic factor as an adjunct therapy to prevent HIV-mediated neuronal degeneration and restore the loss of synaptic connections.

SUN11602, a novel aniline compound, mimics the neuroprotective mechanisms of basic fibroblast growth factor

Basic fibroblast growth factor (bFGF) offers some measure of protection against excitotoxic neuronal injuries by upregulating the expression of the calcium-binding protein calbindin-D28k (Calb). The newly synthesized small molecule 4-({4-[[(4-amino-2,3,5,6-tetramethylanilino)acetyl](methyl)amino]-1-piperidinyl}methyl)benzamide (SUN11602) mimics the neuroprotective effects of bFGF, and thus, we examined how SUN11602 exerts its actions on neurons in toxic conditions of glutamate. In primary cultures of rat cerebrocortical neurons, SUN11602 and bFGF prevented glutamate-induced neuronal death. This neuroprotection, which occurred in association with the augmented phosphorylation of the bFGF receptor-1 (FGFR-1) and the extracellular signal-regulated kinase-1/2 (ERK-1/2), was abolished by pretreatment with PD166866 (a FGFR-1 tyrosine kinase-specific inhibitor) and PD98059 (a mitogen-activated protein kinase [MAPK]/[ERK-1/2] kinase [MEK] inhibitor). In addition, SUN11602 and bFGF increased the levels of CALB1 gene expression in cerebrocortical neurons. Whether this neuroprotection was linked to Calb was investigated with primary cultures of cerebrocortical neurons from homozygous knockout (Calb(-/-)) and wild-type (WT) mice. In WT mice, SUN11602 and bFGF increased the levels of newly synthesized Calb in cerebrocortical neurons and suppressed the glutamate-induced rise in intracellular Ca(2+). This Ca(2+)-capturing ability of Calb allowed the neurons to survive severe toxic conditions of glutamate. In contrast, Calb levels remained unchanged in Calb(-/-) mice after exposure to SUN11602 or bFGF, and due to a loss of function of the gene, these neurons were no longer resistant to toxic conditions of glutamate. These findings indicated that SUN11602 activated a number of cellular molecules (FGFR-1, MEK/ERK intermediates, and Calb) and consequently contributed to intracellular Ca(2+) homeostasis as observed in the case of bFGF.

Metabolic reserve as a determinant of cognitive aging

Mild cognitive impairment (MCI) and Alzheimer's disease (AD) represent points on a continuum of cognitive performance in aged populations. Cognition may be impaired or preserved in the context of brain aging. One theory to account for memory maintenance in the context of extensive pathology involves 'cognitive reserve', or the ability to compensate for neuropathology through greater recruitment of remaining neurons. In this review, we propose a complementary hypothesis of 'metabolic reserve', where a brain with high metabolic reserve is characterized by the presence of neuronal circuits that respond adaptively to perturbations in cellular and somatic energy metabolism and thereby protects against declining cognition. Lifestyle determinants of metabolic reserve, such as exercise, reduced caloric intake, and intake of specific dietary components can promote neuroprotection, while pathological states arising from sedentary lifestyles and excessive caloric intake contribute to neuronal endangerment. This bidirectional relationship between metabolism and cognition may be mediated by alterations in central insulin and neurotrophic factor signaling and glucose metabolism, with downstream consequences for accumulation of amyloid-β and hyperphosphorylated tau. The metabolic reserve hypothesis is supported by epidemiological findings and the spectrum of individual cognitive trajectories during aging, with additional data from animal models identifying potential mechanisms for this relationship. Identification of biomarkers for metabolic reserve could assist in generating a predictive model for the likelihood of cognitive decline with aging.

Effect of PACAP in central and peripheral nerve injuries

Pituitary adenylate cyclase activating polypeptide (PACAP) is a bioactive peptide with diverse effects in the nervous system. In addition to its more classic role as a neuromodulator, PACAP functions as a neurotrophic factor. Several neurotrophic factors have been shown to play an important role in the endogenous response following both cerebral ischemia and traumatic brain injury and to be effective when given exogenously. A number of studies have shown the neuroprotective effect of PACAP in different models of ischemia, neurodegenerative diseases and retinal degeneration. The aim of this review is to summarize the findings on the neuroprotective potential of PACAP in models of different traumatic nerve injuries. Expression of endogenous PACAP and its specific PAC1 receptor is elevated in different parts of the central and peripheral nervous system after traumatic injuries. Some experiments demonstrate the protective effect of exogenous PACAP treatment in different traumatic brain injury models, in facial nerve and optic nerve trauma. The upregulation of endogenous PACAP and its receptors and the protective effect of exogenous PACAP after different central and peripheral nerve injuries show the important function of PACAP in neuronal regeneration indicating that PACAP may also be a promising therapeutic agent in injuries of the nervous system.

Anti-Inflammatory Effect of Dohongsamultang through Inhibition of Nuclear Factor-κB Activation in Peripheral Blood Mononuclear Cells of Patients with Cerebral Infarction

The Korean indigenous medicine "Dohongsamultang (DHSMT)" has long been used for various cerebrovascular diseases. However, the exact mechanism for the anti-inflammatory effect of DHSMT is not completely understood. The aim of the present study is to elucidate how DHSMT modulates the inflammatory reaction in lipopolysaccaride (LPS)-stimulated peripheral mononuclear cells from cerebral infarction (CI) patients. Production and expression of cytokine was measured via the ELISA and RT-PCR methods. The level of nuclear factor-kappa B (NF-κB)/Rel A protein and NF-κB DNA binding activity were determined via the Western blot analysis and transcription factor enzyme-linked immunoassay. It showed that DHSMT inhibited the production of TNF-α, IL-1β, and IL-6 induced by LPS in a dose-dependent manner ( p < 0.05). The maximal inhibition rates for TNF-α, IL-1β, and IL-6 production by DHSMT were about 50.18%, 32.13%, and 38.03%, respectively. DHSMT inhibited the TNF-α mRNA expression in a dose-dependent manner. We also showed that the inhibitory effect of DHSMT is through the suppression of the NF-κB pathway. The study suggests an important molecular mechanism by GMGHT to reduce inflammation, which might explain its beneficial effect in the regulation of inflammatory reactions.

Time for a neurorestorative therapy in stroke

Stroke remains one of the main causes of death and disability worldwide. The aging of the population is likely to result in a dramatic increase in the burden of stroke. Thus, it is not surprising that the pharmaceutical industry has invested much money in the development of pharmacotherapies for ischemic stroke. Promising experimental data, however, have almost consistently failed to produce a clinically effective neuroprotective or neurorestorative drug. Only intravenous recombinant tissue plasminogen activator (rtPA) has been approved for the treatment of acute ischemic stroke. Many pharmaceutical companies have scaled down their stroke programs and despite the unmet need, activity in the field is almost frozen. Trafermin, a recombinant form of human basic fibroblast growth factor (bFGF), is a good example of a translational failure in neuroprotection. However, trafermin may also promote neuronal plasticity after cerebral insults. Thus, clinical trials with trafermin in stroke are warranted but should be based on neuronal restoration rather than acute neuroprotection.

Enhancement of nose-to-brain delivery of basic fibroblast growth factor for improving rat memory impairments induced by co-injection of β-amyloid and ibotenic acid into the bilateral hippocampus

Basic fibroblast growth factor (bFGF) delivery to the brain of animals appears to be an emerging potential therapeutic approach to neurodegenerative diseases, such as Alzheimer's disease (AD). The intranasal route of administration could provide an alternative to intracerebroventricular infusion. A nasal spray of bFGF had been developed previously and the objective of the present study was to investigate whether bFGF nasal spray could enhance brain uptake of bFGF and ameliorate memory impairment induced by co-injection of β-amyloid(25-35) and ibotenic acid into bilateral hippocampus of rats. The results of brain uptake study showed that the AUC(0-12h) of bFGF nasal spray in olfactory bulb, cerebrum, cerebellum and hippocampus was respectively 2.47, 2.38, 2.56 and 2.19 times that of intravenous bFGF solution, and 1.11, 1.95, 1.40 and 1.93 times that of intranasal bFGF solution, indicating that intranasal administration of bFGF nasal spray was an effective means of delivering bFGF to the brain, especially to cerebrum and hippocampus. In Morris water maze tasks, intravenous administration of bFGF solution at high dose (40 μg/kg) showed little improvement on spatial memory impairment. In contrast, bFGF solution of the same dose following intranasal administration could significantly ameliorate spatial memory impairment. bFGF nasal spray obviously improved spatial memory impairment even at a dose half (20 μg/kg) of bFGF solution, recovered their acetylcholinesterase and choline acetyltransferase activity to the sham control level, and alleviated neuronal degeneration in rat hippocampus, indicating neuroprotective effects on the central nerve system. In a word, bFGF nasal spray may be a new formulation of great potential for treating AD.

Angiogenesis, neurogenesis and neuroplasticity in ischemic stroke

Only very little is know about the neurovascular niche after cardioembolic stroke. Three processes implicated in neurorepair: angiogenesis, neurogenesis and synaptic plasticity, would be naturally produced in adult brains, but also could be stimulated through endogen neurorepair phenomena. Angiogenesis stimulation generates new vessels with the aim to increase collateral circulation. Neurogenesis is controlled by intrinsic genetic mechanisms and growth factors but also ambiental factors are important. The leading process of the migrating neural progenitor cells (NPCs) is closely associated with blood vessels, suggesting that this interaction provides directional guidance to the NPCs. These findings suggest that blood vessels play an important role as a scaffold for NPCs migration toward the damaged brain region. DNA microarray technology and blood genomic profiling in human stroke provided tools to investigate the expression of thousands of genes. Critical comparison of gene expression profiles after stroke in humans with those in animal models should lead to a better understanding of the pathophysiology of brain ischaemia. Probably the most important part of early recovery after stroke is limited capacity of penumbra/infarct neurones to recover. It became more clear in the last years, that penumbra is not just passively dying over time but it is also actively recovering. This initial plasticity in majority contributes towards later neurogenesis, angiogenesis and final recovery. Penumbra is a principal target in acute phase of stroke. Thus, the origin of newly formed vessels and the pathogenic role of neovascularization and neurogenesis are important unresolved issues in our understanding of the mechanisms after stroke. Biomaterials for promoting brain protection, repair and regeneration are new hot target. Recently developed biomaterials can enable and increase the target delivery of drugs or therapeutic proteins to the brain, allow cell or tissue transplants to be effectively delivered to the brain and help to rebuild damaged circuits. These new approaches are gaining clear importance because nanotechnology allows better control over material-cell interactions that induce specific developmental processes and cellular responses including differentiation, migration and outgrowth.

Human umbilical mesenchymal stem cells promote recovery after ischemic stroke

BACKGROUND AND PURPOSE

Stroke is a cerebrovascular defect that leads to many adverse neurological complications. Current pharmacological treatments for stroke remain unclear in their effectiveness, whereas stem cell transplantation shows considerable promise. Previously, we have shown that human umbilical mesenchymal stem cells (HUMSCs) can differentiate into neurons in neuronal-conditioned medium. Here we evaluate the therapeutic potential of HUMSC transplantation for ischemic stroke in rats.

METHODS

Focal cerebral ischemia was produced by middle cerebral artery occlusion and reperfusion. The HUMSCs treated with neuronal-conditioned medium or not treated were transplanted into the ischemic cortex 24 hours after surgery.

RESULTS

Histology and MRI revealed that rats implanted with HUMSCs treated with neuronal-conditioned medium or not treated exhibited a trend toward less infarct volume and significantly less atrophy compared with the control group, which received no HUMSCs. Moreover, rats receiving HUMSCs showed significant improvements in motor function, greater metabolic activity of cortical neurons, and better revascularization in the infarct cortex. Implanted HUMSCs, treated or not treated, survived in the infarct cortex for at least 36 days and released neuroprotective and growth-associated cytokines, including brain-derived neurotrophic factor, platelet-derived growth factor-AA, basic fibroblast growth factor, angiopoietin-2, CXCL-16, neutrophil-activating protein-2, and vascular endothelial growth factor receptor-3.

CONCLUSIONS

Our results demonstrate the therapeutic benefits of HUMSC transplantation for ischemic stroke, likely due to the ability of the cells to produce growth-promoting factors. Thus, HUMSC transplantation may be an effective therapy in the future.

Effects of neural progenitor cells on sensorimotor recovery and endogenous repair mechanisms after photothrombotic stroke

BACKGROUND AND PURPOSE

Intravenous neural progenitor cell (NPC) treatment was shown to improve functional recovery after experimental stroke. The underlying mechanisms, however, are not completely understood so far. Here, we investigated the effects of systemic NPC transplantation on endogenous neurogenesis and dendritic plasticity of host neurons.

METHODS

Twenty-four hours after photothrombotic ischemia, adult rats received either 5 million NPC or placebo intravenously. Behavioral tests were performed weekly up to 4 weeks after ischemia. Endogenous neurogenesis, dendritic length, and dendritic branching of cortical pyramid cells and microglial activation were quantified.

RESULTS

NPC treatment led to a significantly improved sensorimotor function measured by the adhesive removal test. The dendritic length and the amount of branch points were significantly increased after NPC transplantation, whereas endogenous neurogenesis was decreased compared to placebo therapy. Decreased endogenous neurogenesis was associated with an increased number of activated microglial cells.

CONCLUSIONS

Our findings suggest that an increased dendritic plasticity might be the structural basis of NPC-induced functional recovery. The decreased endogenous neurogenesis after NPC treatment seems to be mediated by microglial activation.

Filtrate of Phellinus linteus Broth Culture Reduces Infarct Size Significantly in a Rat Model of Permanent Focal Cerebral Ischemia

Phellinus linteus, a natural growing mushroom, has been known to exhibit anti-tumor, anti-inflammatory, anti-allergic and anti-oxidant effects. Aiming to exploit the neuroprotective effects of P. linteus, we evaluated its effects on infarct volume reduction in a rat model of focal cerebral ischemia. Male Sprague-Dawley rats were subjected to right middle cerebral artery occlusion. Filtrate of P. linteus broth culture (various doses), fractionated filtrate (based on molecular weight) or control medium was administered intraperitoneally to rats before or after ischemia induction. Rats were killed at 24 h after the stroke surgery. Cortical and caudoputaminal infarct volumes were determined separately using an image analysis program following staining with 2,3,5-triphenyltetrazolium chloride. Significant cortical infarct volume reductions were found in the pre-treatment groups (30 and 60 minutes before onset of cerebral ischemia) compared with the control group, showing dose dependence. Posttreatment (30 minutes after ischemic onset) also significantly reduced cortical infarct volume. Furthermore, the higher molecular weight (≥12 000) fraction of the culture filtrate was more effective compared with the lower molecular weight fraction. The present findings suggest that P. linteus may be a new promising approach for the treatment of focal cerebral ischemia, with the additional benefit of a wide therapeutic time window since significant infarct volume reduction is obtained by administration even after the ischemic event. Our finding that the higher molecular weight fraction of the P. linteus culture filtrate demonstrated more prominent effect may provide a clue to identify the neuroprotective substances and mechanisms.

Post-treatment with amphetamine enhances reinnervation of the ipsilateral side cortex in stroke rats

Amphetamine (AM) treatment has been shown to alter behavioral recovery after ischemia caused by embolism, permanent unilateral occlusion of the common carotid and middle cerebral arteries, or unilateral sensorimotor cortex ablation in rats. However, the behavioral results are inconsistent possibly due to difficulty controlling the size of the lesion before treatment. There is also evidence that AM promotes neuroregeneration in the cortex contralateral to the infarction; however, the effects of AM in the ipsilateral cortex remain unclear. The purpose of this study was to employ T2-weighted imaging (T2WI) to establish controlled criteria for AM treatment and to examine neuroregenerative effects in both cortices after stroke. Adult rats were anesthetized, and the right middle cerebral artery was ligated for 90 min to generate lesions in the ipsilateral cortex. Animals were separated into two equal treatment groups (AM or saline) according to the size of infarction, measured by T2WI at 2days after stroke. AM or saline was administered to stroke rats every third day starting on day 3 for 4weeks. AM treatment significantly reduced neurological deficits, as measured by body asymmetry and Bederson's score. T2WI and diffusion tensor imaging (DTI) were used to examine the size of infarction and axonal reinnervation, respectively, before and following treatment on days 2, 10 and 25 after stroke. AM treatment reduced the volume of tissue loss on days 10 and 25. A significant increase in fractional anisotropy ratio was found in the ipsilateral cortex after repeated AM administration, suggesting a possible increase in axonal outgrowth in the lesioned side cortex. Western analysis indicated that AM significantly increased the expression of synaptophysin ipsilaterally and neurofilament bilaterally. AM also enhanced matrix metalloproteinase (MMP) enzymatic activity, determined by MMP zymography in the lesioned side cortex. qRT-PCR was used to examine the expression of trophic factors after the 1st and 2nd doses of AM or saline injection. The expression of BDNF, but not BMP7 or CART, was significantly enhanced by AM in the lesioned side cortex. In conclusion, post-stroke treatment with AM facilitates behavioral recovery, which is associated with an increase in fractional anisotropy activity, enhanced fiber growth in tractography, synaptogenesis, upregulation of BDNF, and MMP activity mainly in the lesioned cortex. Our data suggest that the ipsilateral cortex may be the major target of action in stroke brain after AM treatment.

Comparison of the post-embolization effects of tissue-plasminogen activator and simvastatin on neurological outcome in a clinically relevant rat model of acute ischemic stroke

Data has emerged, largely from non-thromboembolic animal models of stroke, that suggests that statins, which have efficacy in preventing strokes when given pre-ischemically, may have a positive effect on stroke even when given post-ischemically, possibly through pleitropic cerebrovascular effects. The goal of this study was to characterize the effects of IV tPA in a clinically relevant model of stroke utilizing a vascular occlusion with a freshly formed clot, and evaluate the effects of post-ischemic administration of simvastatin on stroke outcome in this model. Neurological deficit, clot burden, and lesion volume were assessed after treatment with tPA in one experiment, and after treatment with simvastatin in another. In the tPA experiment, treatment with 10mg/kg of tPA IV (with 20% given as an initial bolus, and 80% given as an infusion over the remaining 30 min), starting within an hour after stroke, resulted in significant reductions, compared with control animals, in neurological deficit (mean+/-SD neuroscores of 21.5+/-21.1 and 30+/-29.3, respectively, p=0.005), clot burden (p=0.010) and lesion volume (p=0.049) at 24h. In the simvastatin experiment on the other hand, treatment with a 20mg/kg of simvastatin as a single intraperitoneal dose within an hour after stroke resulted in no salutary effects on neurological deficit, clot burden or lesion volume compared with controls at 24h. These results suggest that more research needs to be done to fully ascertain the therapeutic potential and optimal dosing paradigm of a post-ischemic treatment with a statin.

Long-term motor improvement after stroke is enhanced by short-term treatment with the alpha-2 antagonist, atipamezole

Drugs that increase central noradrenergic activity have been shown to enhance the rate of recovery of motor function in pre-clinical models of brain damage. Less is known about whether noradrenergic agents can improve the extent of motor recovery and whether such improvement can be sustained over time. This study was designed to determine if increasing central noradrenergic tone using atipamezole, an alpha-2 adrenoceptor antagonist, could induce a long-term improvement in motor performance in rats subjected to ischemic brain damage caused by permanent middle cerebral artery occlusion. The importance of pairing physical "rehabilitation" with enhanced noradrenergic activity was also investigated. Atipamezole (1 mg/kg, s.c.) or vehicle (sterile saline) was administered once daily on Days 2-8 post-operatively. Half of each drug group was housed under enriched environment conditions supplemented with daily focused activity sessions while the other half received standard housing with no focused activity. Skilled motor performance in forelimb reaching and ladder rung walking was assessed for 8 weeks post-operatively. Animals receiving atipamezole plus rehabilitation exhibited significantly greater motor improvement in both behavioral tests as compared to vehicle-treated animals receiving rehabilitation. Interestingly, animals receiving atipamezole without rehabilitation exhibited a significant motor improvement in the ladder rung walk test but not the forelimb reaching test. These results suggest that a short-term increase in noradrenergic activity can lead to sustained motor improvement following stroke, especially when paired with rehabilitation.

Selective long-term reorganization of the corticospinal projection from the supplementary motor cortex following recovery from lateral motor cortex injury

Brain injury affecting the frontal motor cortex or its descending axons often causes contralateral upper extremity paresis. Although recovery is variable, the underlying mechanisms supporting favorable motor recovery remain unclear. Because the medial wall of the cerebral hemisphere is often spared following brain injury and recent functional neuroimaging studies in patients indicate a potential role for this brain region in the recovery process, we investigated the long-term effects of isolated lateral frontal motor cortical injury on the corticospinal projection (CSP) from intact, ipsilesional supplementary motor cortex (M2). After injury to the arm region of the primary motor (M1) and lateral premotor (LPMC) cortices, upper extremity recovery is accompanied by terminal axon plasticity in the contralateral CSP but not the ipsilateral CSP from M2. Furthermore, significant contralateral plasticity occurs only in lamina VII and dorsally within lamina IX. Thus, selective intraspinal sprouting transpires in regions containing interneurons, flexor-related motor neurons, and motor neurons supplying intrinsic hand muscles, which all play important roles in mediating reaching and digit movements. After recovery, subsequent injury of M2 leads to reemergence of hand motor deficits. Considering the importance of the CSP in humans and the common occurrence of lateral frontal cortex injury, these findings suggest that spared supplementary motor cortex may serve as an important therapeutic target that should be considered when designing acute and long-term postinjury patient intervention strategies aimed to enhance the motor recovery process following lateral cortical trauma.

The beta-hCG+erythropoietin in acute stroke (BETAS) study: a 3-center, single-dose, open-label, noncontrolled, phase IIa safety trial

BACKGROUND AND PURPOSE

Animal data suggest the use of beta-human chorionic gonadotropin followed by erythropoietin to promote brain repair after stroke. The current study directly translated these results by evaluating safety of this sequential growth factor therapy through a 3-center, single-dose, open-label, noncontrolled, Phase IIa trial.

METHODS

Patients with ischemic stroke 24 to 48 hours old and National Institutes of Health Stroke Scale score of 6 to 24 started a 9-day course of beta-human chorionic gonadotropin (once daily on Days 1, 3, and 5 of study participation) followed by erythropoietin (once daily on Days 7, 8, and 9 of study participation). This study also evaluated performance of serially measured domain-specific end points.

RESULTS

A total of 15 patients were enrolled. Two deaths occurred, neither related to study medications. No safety concerns were noted among clinical or laboratory measures, including screening for deep vein thrombosis and serial measures of serum hemoglobin. In several instances, domain-specific end points provided greater insight into impairments as compared with global outcome measures.

CONCLUSIONS

Results support the safety of this sequential, 2-growth factor therapy initiated 24 to 48 hours after stroke onset.

Human neural stem cell grafts modify microglial response and enhance axonal sprouting in neonatal hypoxic-ischemic brain injury

BACKGROUND AND PURPOSE

Hypoxic-ischemic (HI) brain injury in newborn infants represents a major cause of cerebral palsy, development delay, and epilepsy. Stem cell-based therapy has the potential to rescue and replace the ischemic tissue caused by HI and to restore function. However, the mechanisms by which stem cell transplants induce functional recovery are yet to be elucidated. In the present study, we sought to investigate the efficacy of human neural stem cells derived from human embryonic stem cells in a rat model of neonatal HI and the mechanisms enhancing brain repair.

METHODS

The human neural stem cells were genetically engineered for in vivo molecular imaging and for postmortem histological tracking. Twenty-four hours after the induction of HI, animals were grafted with human neural stem cells into the forebrain. Motor behavioral tests were performed the fourth week after transplantation. We used immunocytochemistry and neuroanatomical tracing to analyze neural differentiation, axonal sprouting, and microglia response. Treatment-induced changes in gene expression were investigated by microarray and quantitative polymerase chain reaction.

RESULTS

Bioluminescence imaging permitted real time longitudinal tracking of grafted human neural stem cells. HI transplanted animals significantly improved in their use of the contralateral impeded forelimb and in the Rotorod test. The grafts showed good survival, dispersion, and differentiation. We observed an increase of uniformly distributed microglia cells in the grafted side. Anterograde neuroanatomical tracing demonstrated significant contralesional sprouting. Microarray analysis revealed upregulation of genes involved in neurogenesis, gliogenesis, and neurotrophic support.

CONCLUSIONS

These results suggest that human neural stem cell transplants enhance endogenous brain repair through multiple modalities in response to HI.

Promoting axonal rewiring to improve outcome after stroke

A limited amount of functional recovery commonly occurs in the weeks and months after stroke, and a number of studies show that such recovery is associated with changes in the brain's functional organization. Measures that augment this reorganization in a safe and effective way may therefore help improve outcome in stroke patients. Here we review some of the evidence for functional and anatomical reorganization under normal physiological conditions, along with strategies that augment these processes and improve outcome after brain injury in animal models. These strategies include counteracting inhibitors of axon growth associated with myelin, activating neurons' intrinsic growth state, enhancing physiological activity, and having behavioral therapy. These approaches represent a marked departure from the recent focus on neuroprotection and may provide a more effective way to improve outcome after stroke.

Inosine alters gene expression and axonal projections in neurons contralateral to a cortical infarct and improves skilled use of the impaired limb

Recovery after stroke and other types of brain injury is restricted in part by the limited ability of undamaged neurons to form compensatory connections. Inosine, a naturally occurring purine nucleoside, stimulates neurons to extend axons in culture and, in vivo, enhances the ability of undamaged neurons to form axon collaterals after brain damage. The molecular changes induced by inosine are unknown, as is the ability of inosine to restore complex functions associated with a specific cortical area. Using a unilateral injury model limited to the sensorimotor cortex, we show that inosine triples the number of corticospinal tract axons that project from the unaffected hemisphere and form synaptic bouton-like structures in the denervated half of the spinal cord. These changes correlate with improved recovery in animals' ability to grasp and consume food pellets with the affected forepaw. Studies using laser-capture microdissection and microarray analysis show that inosine profoundly affects gene expression in corticospinal neurons contralateral to the injury. Inosine attenuates transcriptional changes caused by the stroke, while upregulating the expression of genes associated with axon growth and the complement cascade. Thus, inosine alters gene expression in neurons contralateral to a stroke, enhances the ability of these neurons to form connections on the denervated side of the spinal cord, and improves performance with the impaired limb.

Angiogenesis after cerebral ischemia

Though the vascular system of the adult brain is extremely stable under normal baseline conditions, endothelial cells start to proliferate in response to brain ischemia. The induction of angiogenesis, primarily in the ischemic boundary zone, enhances oxygen and nutrient supply to the affected tissue. Additionally, the generation of new blood vessels facilitates highly coupled neurorestorative processes including neurogenesis and synaptogenesis which in turn lead to improved functional recovery. To take advantage of angiogenesis as a therapeutic concept for stroke treatment, the knowledge of the precise molecular mechanisms is mandatory. Especially, since a couple of growth factors involved in post-ischemic angiogenesis may have detrimental adverse effects in the brain by increasing vascular permeability. This article summarizes the knowledge of molecular mechanisms of angiogenesis following cerebral ischemia. Finally, experimental pharmacological and cellular approaches to stimulate and enhance post-ischemic angiogenesis are discussed.

Basic fibroblast growth factor stimulates the proliferation and differentiation of neural stem cells in neonatal rats after ischemic brain injury

A little is known about the proliferation and fate of neural stem cells in the subventricular zone (SVZ) after cerebral ischemia. However, how endogenous neural stem cells are activated in the premature brain is not clear, although basic fibroblast growth factor (bFGF) is important in neurogenesis. To investigate the effect of bFGF on the proliferation and differentiation of neural stem cells after brain ischemia, we observed cellular changes in the subventricular zone (SVZ) of 3-day-old rats (approximately equivalent to premature infants) using immunofluorescence assays, Western blot analysis, and real-time quantitative PCR methods. The bilateral common carotid artery (BCCA) was occluded in 108 animals, then half received bFGF 10ng/g. Besides, 54 rats without ischemia as normal control. Proliferating cells were labeled by bromodeoxyuridine (BrdU) through intraperitoneal injection in a pulsed or a cumulative protocol. Rats were killed at 4, 7, and 14 days after ischemic injury. The number of proliferating cells in the SVZ in bFGF-treated rats was higher than that in untreated rats; bFGF also promoted neural stem cell differentiation into neurons, astrocytes, and oligodendrocytes. Western blot analysis and real-time quantitative PCR assays confirmed these results. We suggest that bFGF promotes the repair of ischemia brain injury through increasing the proliferation of neural stem cells and their differentiation into neurons, astrocytes, and oligodendrocytes.

Motor recovery and axonal plasticity with short-term amphetamine after stroke

BACKGROUND AND PURPOSE

There is considerable debate regarding the efficacy of amphetamine to facilitate motor recovery after stroke or experimental brain injury. Different drug dosing and timing schedules and differing physical rehabilitation strategies may contribute to outcome variability. The present study was designed to ascertain (1) whether short-term amphetamine could induce long-term functional motor recovery in rats after an ischemic lesion modeling stroke in humans; (2) how different levels of physical rehabilitation interact with amphetamine to enhance forelimb-related functional outcome; and (3) whether motor improvement was associated with axonal sprouting from intact corticoefferent pathways originating in the contralesional forelimb motor cortex.

METHODS

After permanent middle cerebral artery occlusion, rats received vehicle or amphetamine during the first postoperative week (2 mg/kg, subcutaneously on Postoperative Days 2, 5, and 8). In both treatment groups, separate cohorts of rats were exposed to different levels of "physical rehabilitation" represented by a control environment, enriched environment, or enriched environment with additional sessions of focused activity. Skilled forelimb performance was assessed using the forelimb reaching task and ladder rung walk test. Anterograde tracing with biotinylated dextran amine was used to assess new fiber outgrowth to denervated motor areas.

RESULTS

All treatment groups showed significant motor improvement as compared with control-housed, vehicle-treated animals. However, animals housed in an enriched environment that received amphetamine paired with focused activity sessions performed significantly better than any other treatment group and was the only group to achieve complete motor recovery (ie, reached preoperative performance) by 8 weeks. This recovery was associated with axonal sprouting into deafferentated subcortical areas from contralesional projection neurons.

CONCLUSIONS

This study suggests that, after stroke, short-term pairing of amphetamine with sufficiently focused activity is an effective means of inducing long-term improvement in forelimb motor function. The anatomic data suggests that corticoefferent plasticity in the form of axonal sprouting contributes to the maintenance of motor recovery.

Use of imaging in restorative stroke trials

Restorative therapies aim to improve behavioral outcome after stroke by promoting repair and restoration. Measures of CNS injury and function might be useful to evaluate such therapies in a clinical trial, for example, by optimizing patient selection or treatment dose. These issues are considered in this review, with specific examples provided.

Down-regulation of neurocan expression in reactive astrocytes promotes axonal regeneration and facilitates the neurorestorative effects of bone marrow stromal cells in the ischemic rat brain

The glial scar, a primarily astrocytic structure bordering the infarct tissue inhibits axonal regeneration after stroke. Neurocan, an axonal extension inhibitory molecule, is up-regulated in the scar region after stroke. Bone marrow stromal cells (BMSCs) reduce the thickness of glial scar wall and facilitate axonal remodeling in the ischemic boundary zone. To further clarify the role of BMSCs in axonal regeneration and its underlying mechanism, the current study focused on the effect of BMSCs on neurocan expression in the ischemic brain. Thirty-one adult male Wistar rats were subjected to 2 h of middle cerebral artery occlusion followed by an injection of 3 x 10(6) rat BMSCs (n = 16) or phosphate-buffered saline (n = 15) into the tail vein 24 h later. Animals were sacrificed at 8 days after stroke. Immunostaining analysis showed that reactive astrocytes were the primary source of neurocan, and BMSC-treated animals had significantly lower neurocan and higher growth associated protein 43 expression in the penumbral region compared with control rats, which was confirmed by Western blot analysis of the brain tissue. To further investigate the effects of BMSCs on astrocyte neurocan expression, single reactive astrocytes were collected from the ischemic boundary zone using laser capture microdissection. Neurocan gene expression was significantly down-regulated in rats receiving BMSC transplantation (n = 4/group). Primary cultured astrocytes showed similar alterations; BMSC coculture during reoxygenation abolished the up-regulation of neurocan gene in astrocytes undergoing oxygen-glucose deprivation (n = 3/group). Our data suggest that BMSCs promote axonal regeneration by reducing neurocan expression in peri-infarct astrocytes.

Intranasally delivered bFGF enhances neurogenesis in adult rats following cerebral ischemia

Basic fibroblast growth factor (bFGF) is a very important mitogenic factor with proved neurogenesis effects in the central nervous system. Intranasal administration can bypass blood-brain barrier and deliver drugs into the brain directly. We investigated whether intranasal administration of bFGF at later time points after ischemia could promote adult neurogenesis and improve neurologic functions. Rats received bFGF or saline intranasally once daily for 6 consecutive days, starting at 1 day after transient middle cerebral artery occlusion (MCAO). Bromodeoxyuridine (BrdU) was injected at 5 and 6 days after MCAO. Rats were killed at 7 or 28 days after MCAO. Neurogenesis was assessed by immunostaining for BrdU and cell type-specific markers. Neurological functions were evaluated by the modified Neurological Severity Scores. Compared with the control animals, intranasal administration of bFGF improved behavioral recovery without affecting infarct size, and enhanced proliferation of progenitor cells in the subventricular zone and the subgranular zone of the dentate gyrus (DG). Furthermore, the new proliferated cells could differentiate into neurons (BrdU+NeuN+ cells) in the striatum and DG at 28 days after MCAO. Intranasal administration of bFGF offers a non-invasive alternative for the treatment of stroke.

Repairing the human brain after stroke. II. Restorative therapies

Spontaneous behavioral recovery is usually limited after stroke, making stroke a leading source of disability. A number of therapies in development aim to improve patient outcomes not by acutely salvaging threatened tissue, but instead by promoting repair and restoration of function in the subacute or chronic phase after stroke. Examples include small molecules, growth factors, cell-based therapies, electromagnetic stimulation, device-based strategies, and task-oriented and repetitive training-based interventions. Stage of development across therapies varies widely, from preclinical to late-phase clinical trials. The optimal methods to prescribe such therapies require further studies, for example, to best identify appropriate patients or to guide features of dosing. Likely, anatomic, functional, and behavioral measures of brain state, as well as measures of injury, will each be useful in this regard. Considerations for clinical trials of restorative therapies are provided, emphasizing both similarities and points of divergence with acute stroke clinical trial design.

Rodent models of global cerebral ischemia

Brain damage after stroke and head injury remains a huge clinical problem. In stroke, the initial cause of the damage is a blockage in a blood vessel (often the middle cerebral artery) and this sets off several pathways that ultimately lead to cell death. Recent studies have demonstrated that several new mechanisms are involved in neuronal death and this has led to an increase in research into novel molecules that might prevent brain damage or improve recuperation post-stroke. There are several models of global cerebral ischemia. Two of the most widely-used models are discussed in detail in UNIT 9.5, the gerbil bilateral carotid artery occlusion (BCAO) model and rat 4-vessel occlusion (4-VO) model. Additionally, several models of focal cerebral ischemia have been developed to mimic the effects of human stroke. The rationale behind the use of animal models, the various types of models and advantage and disadvantages of each model are presented.

Repairing the human brain after stroke: I. Mechanisms of spontaneous recovery

Stroke remains a leading cause of adult disability. Some degree of spontaneous behavioral recovery is usually seen in the weeks after stroke onset. Variability in recovery is substantial across human patients. Some principles have emerged; for example, recovery occurs slowest in those destined to have less successful outcomes. Animal studies have extended these observations, providing insight into a broad range of underlying molecular and physiological events. Brain mapping studies in human patients have provided observations at the systems level that often parallel findings in animals. In general, the best outcomes are associated with the greatest return toward the normal state of brain functional organization. Reorganization of surviving central nervous system elements supports behavioral recovery, for example, through changes in interhemispheric lateralization, activity of association cortices linked to injured zones, and organization of cortical representational maps. A number of factors influence events supporting stroke recovery, such as demographics, behavioral experience, and perhaps genetics. Such measures gain importance when viewed as covariates in therapeutic trials of restorative agents that target stroke recovery.

Manganese-enhanced MRI of brain plasticity in relation to functional recovery after experimental stroke

Restoration of function after stroke may be associated with structural remodeling of neuronal connections outside the infarcted area. However, the spatiotemporal profile of poststroke alterations in neuroanatomical connectivity in relation to functional recovery is still largely unknown. We performed in vivo magnetic resonance imaging (MRI)-based neuronal tract tracing with manganese in combination with immunohistochemical detection of the neuronal tracer wheat-germ agglutinin horseradish peroxidase (WGA-HRP), to assess changes in intra- and interhemispheric sensorimotor network connections from 2 to 10 weeks after unilateral stroke in rats. In addition, functional recovery was measured by repetitive behavioral testing. Four days after tracer injection in perilesional sensorimotor cortex, manganese enhancement and WGA-HRP staining were decreased in subcortical areas of the ipsilateral sensorimotor network at 2 weeks after stroke, which was restored at later time points. At 4 to 10 weeks after stroke, we detected significantly increased manganese enhancement in the contralateral hemisphere. Behaviorally, sensorimotor functions were initially disturbed but subsequently recovered and plateaued 17 days after stroke. This study shows that manganese-enhanced MRI can provide unique in vivo information on the spatiotemporal pattern of neuroanatomical plasticity after stroke. Our data suggest that the plateau stage of functional recovery is associated with restoration of ipsilateral sensorimotor pathways and enhanced interhemispheric connectivity.

Brain-derived neurotrophic factor but not forced arm use improves long-term outcome after photothrombotic stroke and transiently upregulates binding densities of excitatory glutamate receptors in the rat brain

BACKGROUND AND PURPOSE

Both application of neurotrophic factors like brain-derived neurotrophic factor (BDNF) and constraint-induced movement therapy like forced arm use have been shown to potentially improve outcome after stroke. The aim of the present study was to check whether postischemic long-term outcome correlates to specific modifications in the abundance of various neurotransmitter receptors.

METHODS

Adult male Wistar rats were subjected to photothrombotic ischemia and assigned to various treatment groups (n=5 each) with end points at 3 and 6 weeks: (1) ischemic control (saline); (2) BDNF (ischemia, 20 microg BDNF); (3) forced arm use (ischemia, saline, and ipsilateral plaster cast for 5 or 14 days for the 3- and 6-week groups, respectively); and (4) combined treatment (combi; ischemia, 20 microg BDNF, forced arm use). Animals received intravenous bolus infusions of saline or BDNF 1 hour 3 and 5 days after ischemia, respectively. A group of sham rats (n=2) served as a control. A battery of behavioral tests was performed before and up to 6 weeks after ischemia. Quantitative in vitro receptor autoradiography was performed on 12-microm-thick cryostat sections using [(3)H]MK-801, [(3)H]AMPA, and [(3)H]muscimol for labeling of NMDA, AMPA, and GABA(A) receptors, respectively.

RESULTS

Best functional outcome was seen after BDNF treatment, whereas vice versa rats with forced arm use did worse in behavioral performance. Improved behavioral outcome was associated with increased perilesional binding densities of NMDA and AMPA receptors 3 weeks after stroke.

CONCLUSIONS

Our findings suggest that transient enhanced neurotransmission as reflected by increased ligand binding of NMDA and AMPA receptors may participate in successful postlesional reorganization processes.

The stroke rehabilitation paradigm

The matrix of stroke rehabilitation is evolving as we look outside the box of traditional therapy type, timing, and intensity of rehabilitation techniques. For inpatient wards, the goal of medical stability and prompt resolution of complications to maximize participation in therapy remains paramount. In the current medical model, we focus on teaching compensatory strategies and rarely on restorative approaches because of time and financial limitations. Researchers aim to identify new technologic and molecular approaches to improve functional outcomes and more accurately predict disability. This article examines different concepts surrounding the comprehensive rehabilitation paradigm of stroke survivors.

Long-term monitoring of post-stroke plasticity after transient cerebral ischemia in mice using in vivo and ex vivo diffusion tensor MRI

WE USED A MURINE MODEL OF TRANSIENT FOCAL CEREBRAL ISCHEMIA TO STUDY: 1) in vivo DTI long-term temporal evolution of the apparent diffusion coefficient (ADC) and diffusion fractional anisotropy (FA) at days 4, 10, 15 and 21 after stroke 2) ex vivo distribution of a plasticity-related protein (GAP-43) and its relationship with the ex vivo DTI characteristics of the striato-thalamic pathway (21 days). All animals recovered motor function. In vivo ADC within the infarct was significantly increased after stroke. In the stroke group, GAP-43 expression and FA values were significantly higher in the ipsilateral (IL) striatum and contralateral (CL) hippocampus compared to the shams. DTI tractography showed fiber trajectories connecting the CL striatum to the stroke region, where increased GAP43 and FA were observed and fiber tracts from the CL striatum terminating in the IL hippocampus.Our data demonstrate that DTI changes parallel histological remodeling and recovery of function.

Vascular endothelial growth factor gene-transferred bone marrow stromal cells engineered with a herpes simplex virus type 1 vector can improve neurological deficits and reduce infarction volume in rat brain ischemia

OBJECTIVE

Several reports recently suggested that vascular endothelial growth factor (VEGF) may have a therapeutic benefit against experimental cerebral infarction animal models. In addition, bone marrow stromal cells (BMSCs) are known to have therapeutic potency in improving neurological deficits after occlusive cerebrovascular diseases. In the present study, we evaluated the hypothesis that intracerebral transplantation of VEGF gene-transferred BMSCs could provide a greater therapeutic effect than intracerebral transplantation of native (non-gene-transformed) BMSCs by using a transient middle cerebral artery occlusion (MCAO) rat model.

METHODS

Adult Wistar rats (Japan SLC, Inc., Hamamatsu, Japan) were anesthetized. VEGF gene-transferred BMSCs engineered with a replication-deficient herpes simplex virus type 1 1764/4-/pR19-hVEGF165 vector, native BMSCs, or phosphate-buffered saline were administered intracerebrally 24 hours after transient MCAO. All animals underwent behavioral testing for 28 days, and the infarction volume was determined 14 days after MCAO. The brain water contents in the ipsilateral and contralateral hemispheres of the MCAO were measured 2 and 7 days after the MCAO. Fourteen days after MCAO, immunohistochemical staining for VEGF was performed.

RESULTS

The group receiving VEGF-modified BMSCs demonstrated significant functional recovery compared with those receiving native BMSCs. Fourteen days after the MCAO, there was a significantly lower infarct volume without aggravating cerebral edema in the group treated with VEGF gene-modified BMSCs compared with the control groups. The transplanted VEGF gene-modified BMSCs strongly expressed VEGF protein for at least 14 days.

CONCLUSION

Our data suggest that the intracerebral transplantation of VEGF gene-transferred BMSCs may provide a more potent autologous cell transplantation therapy for stroke than the transplantation of native BMSCs alone.

Plasticity and remodeling of brain

The injured brain can be stimulated to amplify its intrinsic restorative processes to improve neurological function. Thus, after stroke, both cell and pharmacological neurorestorative treatments, amplify the induction of brain neurogenesis and angiogenesis, and thereby reduce neurological deficits. In this manuscript, we describe the use of bone marrow mesenchymal cells (MSCs) and erythropoietin (EPO) as examples of cell-based and pharmacological neurorestorative treatments, respectively, for both stroke and a mouse model of experimental autoimmune encephalomyelitis (EAE). We demonstrate that these therapies significantly improve neurological function with treatment initiated after the onset of injury and concomitantly promote brain plasticity. The application of MRI to monitor changes in the injured brain associated with reduction of neurological deficit is also described.

Rewiring the injured CNS: lessons from the optic nerve

The optic nerve offers a number of advantages for investigating mechanisms that govern axon regeneration in the CNS. Although mature retinal ganglion cells (RGCs) normally show no ability to regenerate injured axons through the optic nerve, this situation can be partially reversed by inducing an inflammatory response in the eye. The secretion of a previously unknown growth factor, oncomodulin, along with co-factors, causes RGCs to undergo dramatic changes in gene expression and regenerate lengthy axons into the highly myelinated optic nerve. By themselves, strategies that counteract inhibitory signals associated with myelin and the glial scar are insufficient to promote extensive regeneration in this system. However, combinatorial treatments that activate neurons' intrinsic growth state and overcome inhibitory signals result in dramatic axon regeneration in vivo. Because of the ease of introducing trophic factors, soluble receptors, drugs, or viruses expressing any gene or small interfering RNA of interest into RGCs, this system is ideal for identifying intracellular signaling pathways, transcriptional cascades, and ligand-receptor interactions that enable axon regeneration to occur in the CNS.

One-year follow-up after bone marrow stromal cell treatment in middle-aged female rats with stroke

BACKGROUND AND PURPOSE

We sought to evaluate the long-term effects of bone marrow stromal cell (BMSC) treatment on retired breeder rats with stroke.

METHODS

Female retired breeder rats were subjected to 2-hour middle cerebral artery occlusion (MCAO) followed by an injection of 2 x 10(6) male BMSCs (n=8) or phosphate-buffered saline (n=11) into the ipsilateral internal carotid artery at 1 day after stroke. The rats were humanely killed 1 year later. Functional tests, in situ hybridization, and histochemical and immunohistochemical staining were performed.

RESULTS

Significant recovery of neurological deficits was found in BMSC-treated rats beginning 2 weeks after cell injection compared with control animals. The beneficial effects of cell transplantation persisted for at least 1 year (P<0.01). In situ hybridization for the Y chromosome showed that donor cells survived in the brains of recipient rats, among which 22.3+/-1.95% of cells expressed the astrocyte marker glial fibrillary acidic protein, 16.8+/-2.13% expressed the neuronal marker microtubule-associated protein 2, and 5.5+/-0.42% and <1% of cells colocalized with the microglial marker IB4 and the endothelial cell marker von Willebrand factor, respectively. Only very few BMSCs, however, were found in peripheral organs such as the heart, lung, liver, spleen, and kidney in recipient rats. BMSCs significantly reduced axonal loss (P<0.01), the thickness of the lesion scar wall (P<0.01), and the number of Nogo-A-positive cells (P<0.05) along the scar border; meanwhile, synaptophysin expression (P<0.05) was significantly increased in BMSC-treated ischemic brains compared with control untreated brains.

CONCLUSIONS

The beneficial effects of BMSCs on ischemic brain tissue persisted for at least 1 year. Most surviving BMSCs were present in the ischemic brain, but very few were found in other organs. The long-term improvement in functional outcome may be related to the structural and molecular changes induced by BMSCs.

The Case for Modality-Specific Outcome Measures in Clinical Trials of Stroke Recovery-Promoting Agents

Clinical trials for acute stroke treatments have often used composite clinical rating scales as primary outcome measures of treatment efficacy. Recent preclinical and clinical studies highlight the opportunity to administer treatments in the subacute and chronic phase of stroke to promote neurological recovery. Because different neurological deficits recover to different extents at different rates after stroke, putative stroke recovery-promoting treatments may exert differential effects on various functional aspects of stroke recovery. For this reason, we propose that the use of modality-specific outcome measures may be best suited as primary end points in clinical trials of stroke recovery-promoting agents. The use of such end points may result in a more selective labeling of stroke recovery treatments.

The effect of SHJKS on cytokines production and NF-kappaB activation in the peripheral blood mononuclear cells of patients with cerebral infarction

The Korean genuine medicine "Seonghyangjeongkisan" (SHJKS) has long been used for various cerebrovascular diseases. However, very little scientific investigation has been carried out. Cytokines involved in the regulation of inflammatory reactions and immune responses may play a role in the pathogenesis of cerebral infarction (CI). The aim of the present study is to elucidate how SHJKS modulates the inflammatory reaction in lipopolysaccaride (LPS) plus phytohaemagglutinin (PHA)-stimulated peripheral mononuclear cells (PBMCs) from CI patients. The amount of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, and IL-8 in PBMC culture supernatant was significantly increased in the LPS plus PHA treated cells compared to unstimulated cells. SHJKS inhibited the TNF-alpha, IL-1beta, IL-6, and IL-8 production in dose dependent manner. Maximal inhibition rate of the TNF-alpha, IL-1beta, IL-6, and IL-8 by SHJGS (1.0 mg/ml) was 68.01 +/- 0.28% (P < 0.01), 52.11 +/- 0.56 % (P < 0.01), 53.42 +/- 0.46 % (P < 0.01), and 46.70 +/- 0.37% (P < 0.05), respectively. In addition, we show that SHJKS suppressed nuclear factor (NF)-kappaB activation induced by LPS plus PHA, leading to suppression of IkappaB-alpha phosphorylation and degradation. These results suggest that SHJKS might have regulatory effects on LPS plus PHA-induced cytokine production and NF-kappaB activation, which might explain its beneficial effect in the treatment of CI.

Role of Endogenous Neural Stem Cells in Neurological Disease and Brain Repair

These examples show that stem-cell-based therapy of neuro-psychiatric disorders will not follow a single scheme, but rather include widely different approaches. This is in accordance with the notion that the impact of stem cell biology on neurology will be fundamental, providing a shift in perspective, rather than introducing just one novel therapeutic tool. Stem cell biology, much like genomics and proteomics, offers a "view from within" with an emphasis on a theoretical or real potential and thereby the inherent openness, which is central to the concept of stem cells. Thus, stem cell biology influences many other, more traditional therapeutic approaches, rather than introducing one distinct novel form of therapy. Substantial advances have been made i n neural stemcell research during the years. With the identification of stem and progenitor cells in the adult brain and the complex interaction of different stem cell compartments in the CNS--both, under physiological and pathological conditions--new questions arise: What is the lineage relationship between t he different progenitor cells in the CNS and how much lineage plasticity exists? What are the signals controlling proliferation and differentiation of neural stem cells and can these be utilized to allow repair of the CNS? Insights in these questions will help to better understand the role of stem cells during development and aging and the possible relation of impaired or disrupted stem cell function and their impact on both the development and treatment of neurological disease. A number o f studies have indicated a limited neuronal and glial regeneration certain pathological conditions. These fundamental observations have already changed our view on understanding neurological disease and the brain's capacity for endogenous repair. The following years will have to show how we can influence andmodulate endogenous repair nisms by increasing the cellular plasticity in the young and aged CNS.

A neural cell adhesion molecule–derived peptide reduces neuropathological signs and cognitive impairment induced by Aβ25-35

By means of i.c.v. administration of preaggregated oligomeric beta-amyloid (Abeta)25-35 peptide it was possible in rats to generate neuropathological signs related to those of early stages of Alzheimer's disease (AD). Abeta25-35-administration induced the deposition of endogenously produced amyloid protein. Furthermore, quantitative immunohistochemistry demonstrated time-related statistically significant increases in amyloid immunoreactivity, tau phosphorylation, microglial activation, and astrocytosis, and stereological investigations demonstrated statistically significant increased neuronal cell death and brain atrophy in response to Abeta25-35. Finally, the Abeta25-35-administration led to a reduced short-term memory as determined by the social recognition test. A synthetic peptide termed FGL derived from the neural cell adhesion molecule (NCAM) was able to prevent or, if already manifest, strongly reduce all investigated signs of Abeta25-35-induced neuropathology and cognitive impairment. The FGL peptide was recently demonstrated to be able to cross the blood-brain-barrier. Accordingly, we found that the beneficial effects of FGL were achieved not only by intracisternal, but also by intranasal and s.c. administration of the peptide. Furthermore, FGL-treatment was shown to inhibit the activity of GSK3beta, a kinase implicated in signaling regulating cell survival, tau phosphorylation and the processing of the amyloid precursor protein (APP). Thus, the peptide induced a statistically significant increase in the fraction of GSK3beta phosphorylated on the Ser9-position, a posttranslational modification known to inhibit the activity of the kinase. Hence, the mode of action of FGL with respect to the preventive and curative effects on Abeta25-35-induced neuropathological manifestations and cognitive impairment involves the modulation of intracellular signal-transduction mediated through GSK3beta.