Inhibited glutamate release by granulocyte-colony stimulating factor after experimental stroke

Granulocyte Colony-Stimulating Factor Improved Core Symptoms of Autism Spectrum Disorder via Modulating Glutamatergic Receptors in the Prefrontal Cortex and Hippocampus of Rat Brains

Chronic neuroinflammation-induced anomalous glutamate receptor activation has been identified as one of the important factors in the pathogenesis of autism spectrum disorder (ASD). Thus, the current study was designed to elucidate the neuroprotective effect of the granulocyte colony-stimulating factor (G-CSF), a haemopoietic growth factor, an anti-inflammatory, and a neuroprotectant to decipher the underlying mechanism(s) in the valproic acid (VPA)-induced experimental model of ASD. Experimentally, the ASD rat model was induced by a single dose of VPA (600 mg/kg; i.p.) on gestation day 12.5 to the pregnant female rats. After birth, pups were treated with vehicle, normal saline 0.9% i.p., risperidone (2.5 mg/kg; i.p.), and G-CSF (10, 35, and 70 μg/kg; i.p.) from postnatal day (PND) 23 to 43. All the groups were subjected to various developmental and behavior tests from birth. The rats were sacrificed on PND 55, and their brain was excised and processed for biochemical parameters (oxidative stress, inflammatory markers, BDNF), histological examination (H&E, Nissl staining), NMDA, and AMPA receptor expression by immunohistochemistry, western blot, and real-time polymerase chain reaction evaluation. Also, the possible interaction of the G-CSF with NMDA and AMPA receptors was evaluated using the in-silico method. The results of the study showed that in VPA-exposed rats, postnatal treatment of G-CSF rescued all the behavioral abnormalities, oxidative stress, and inflammatory parameters in a dose-dependent manner while risperidone did not show any significant results. The in-silico analysis showed the direct interaction of G-CSF with NMDA and AMPA receptors. The upregulated expression of NMDA and AMPA both in the prefrontal cortex as well as hippocampus was alleviated by G-CSF thereby validating its anti-inflammatory and excitoprotective properties. Thus, G-CSF demonstrated neuroprotection against the core symptoms of autism in the VPA-induced rodent model, making it a potential candidate for the treatment of ASD.

Granulocyte-Colony Stimulating Factor Reduces Cocaine-Seeking and Downregulates Glutamatergic Synaptic Proteins in Medial Prefrontal Cortex

Psychostimulant use disorder is a major public health issue, and despite the scope of the problem there are currently no Food and Drug Administration (FDA)-approved treatments. There would be tremendous utility in development of a treatment that could help patients both achieve and maintain abstinence. Previous work from our group has identified granulocyte-colony stimulating factor (G-CSF) as a neuroactive cytokine that alters behavioral response to cocaine, increases synaptic dopamine release, and enhances cognitive flexibility. Here, we investigate the role of G-CSF in affecting extinction and reinstatement of cocaine-seeking and perform detailed characterization of its proteomic effects in multiple limbic substructures. Male Sprague Dawley rats were injected with PBS or G-CSF during (1) extinction or (2) abstinence from cocaine self-administration, and drug seeking behavior was measured. Quantitative assessment of changes in the proteomic landscape in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) were performed via data-independent acquisition (DIA) mass spectrometry analysis. Administration of G-CSF during extinction accelerated the rate of extinction, and administration during abstinence attenuated cue-induced cocaine-seeking. Analysis of global protein expression demonstrated that G-CSF regulated proteins primarily in mPFC that are critical to glutamate signaling and synapse maintenance. Taken together, these findings support G-CSF as a viable translational research target with the potential to reduce drug craving or seeking behaviors. Importantly, recombinant G-CSF exists as an FDA-approved medication which may facilitate rapid clinical translation. Additionally, using cutting-edge multiregion discovery proteomics analyses, these studies identify a novel mechanism underlying G-CSF effects on behavioral plasticity.SIGNIFICANCE STATEMENT Pharmacological treatments for psychostimulant use disorder are desperately needed, especially given the disease's chronic, relapsing nature. However, there are currently no Food and Drug Administration (FDA)-approved pharmacotherapies. Emerging evidence suggests that targeting the immune system may be a viable translational research strategy; preclinical studies have found that the neuroactive cytokine granulocyte-colony stimulating factor (G-CSF) alters cocaine reward and reinforcement and can enhance cognitive flexibility. Given this basis of evidence we studied the effects of G-CSF treatment on extinction and reinstatement of cocaine seeking. We find that administration of G-CSF accelerates extinction and reduces cue-induced drug seeking after cocaine self-administration. In addition, G-CSF leads to downregulation of synaptic glutamatergic proteins in medial prefrontal cortex (mPFC), suggesting that G-CSF influences drug seeking via glutamatergic mechanisms.

The role of neurogenesis in neurorepair after ischemic stroke

Stroke consists of an abrupt reduction of cerebral blood flow resulting in hypoxia that triggers an excitotoxicity, oxidative stress, and neuroinflammation. After the ischemic process, neural precursor cells present in the subventricular zone of the lateral ventricle and subgranular zone of the dentate gyrus proliferate and migrate towards the lesion, contributing to the brain repair. The neurogenesis is induced by signal transduction pathways, growth factors, attractive factors for neuroblasts, transcription factors, pro and anti-inflammatory mediators and specific neurotransmissions. However, this endogenous neurogenesis occurs slowly and does not allow a complete restoration of brain function. Despite that, understanding the mechanisms of neurogenesis could improve the therapeutic strategies for brain repair. This review presents the current knowledge about brain repair process after stroke and the perspectives regarding the development of promising therapies that aim to improve neurogenesis and its potential to form new neural networks.

Extension of Tissue Plasminogen Activator Treatment Window by Granulocyte-Colony Stimulating Factor in a Thromboembolic Rat Model of Stroke

When given beyond 4.5 h of stroke onset, tissue plasminogen activator (tPA) induces deleterious side effects in the ischemic brain, notably, hemorrhagic transformation (HT). We examined the efficacy of granulocyte-colony stimulating factor (G-CSF) in reducing delayed tPA-induced HT, cerebral infarction, and neurological deficits in a thromboembolic (TE) stroke model, and whether the effects of G-CSF were sustained for longer periods of recovery. After stroke induction, rats were given intravenous saline (control), tPA (10 mg/kg), or G-CSF (300 μg/kg) + tPA 6 h after stroke. We found that G-CSF reduced delayed tPA-associated HT by 47%, decreased infarct volumes by 33%, and improved motor and neurological deficits by 15% and 25%, respectively. It also prevented delayed tPA treatment-induced mortality by 46%. Immunohistochemistry showed 1.5- and 1.8-fold enrichment of the endothelial progenitor cell (EPC) markers CD34+ and VEGFR2 in the ischemic cortex and striatum, respectively, and 1.7- and 2.8-fold increases in the expression of the vasculogenesis marker von Willebrand factor (vWF) in the ischemic cortex and striatum, respectively, in G-CSF-treated rats compared with tPA-treated animals. Flow cytometry revealed increased mobilization of CD34+ cells in the peripheral blood of rats given G-CSF. These results corroborate the efficacy of G-CSF in enhancing the therapeutic time window of tPA for stroke treatment via EPC mobilization and enhancement of vasculogenesis.

Stem cell therapies in preclinical models of stroke. Is the aged brain microenvironment refractory to cell therapy?

Stroke is a devastating disease demanding vigorous search for new therapies. Initial enthusiasm to stimulate restorative processes in the ischemic brain by means of cell-based therapies has meanwhile converted into a more balanced view recognizing impediments that may be related to unfavorable age-associated environments. Recent results using a variety of drug, cell therapy or combination thereof suggest that, (i) treatment with Granulocyte-Colony Stimulating Factor (G-CSF) in aged rats has primarily a beneficial effect on functional outcome most likely via supportive cellular processes such as neurogenesis; (ii) the combination therapy, G-CSF with mesenchymal cells (G-CSF+BM-MSC or G-CSF+BM-MNC) did not further improve behavioral indices, neurogenesis or infarct volume as compared to G-CSF alone in aged animals; (iii) better results with regard to integration of transplanted cells in the aged rat environment have been obtained using iPS of human origin; (iv) mesenchymal cells may be used as drug carriers for the aged post-stroke brains.

CONCLUSION

While the middle aged brain does not seem to impair drug and cell therapies, in a real clinical practice involving older post-stroke patients, successful regenerative therapies would have to be carried out for a much longer time.

Translating G-CSF as an Adjunct Therapy to Stem Cell Transplantation for Stroke

Among recently investigated stroke therapies, stem cell treatment holds great promise by virtue of their putative ability to replace lost cells, promote endogenous neurogenesis,and produce behavioral and functional improvement through their "bystander effects." Translating stem cell in the clinic, however, presents a number of technical difficulties. A strategy suggested to enhance therapeutic utility of stem cells is combination therapy, i.e., co-transplantation of stem cells or adjunct treatment with pharmacological agents and substrates,which is assumed to produce more profound therapeutic benefits by circumventing limitations of individual treatments and facilitating complementary brain repair processes. We previously demonstrated enhanced functional effects of cotreatment with granulocyte-colony stimulating factor (GCSF)and human umbilical cord blood cell (hUCB) transplantation in animal models of traumatic brain injury (TBI). Here,we suggest that the aforementioned combination therapy may also produce synergistic effects in stroke. Accordingly, G-CSF treatment may reduce expression of pro-inflammatory cytokines and enhance neurogenesis rendering a receptive microenvironment for hUCB engraftment. Adjunct treatment of GCSF with hUCB may facilitate stemness maintenance and guide neural lineage commitment of hUCB cells. Moreover, regenerative mechanisms afforded by G-CSF-mobilized endogenous stem cells, secretion of growth factors by hUCB grafts and G-CSF-recruited endothelial progenitor cells(EPCs), as well as the potential graft–host integration that may promote synaptic circuitry re-establishment could altogether produce more pronounced functional improvement in stroked rats subjected to a combination G-CSF treatment and hUCB transplantation. Nevertheless, differences in pathology and repair processes underlying TBI and stroke deserve consideration when testing the effects of combinatorial G-CSF and hUCB cell transplantation for stroke treatment. Further studies are also required to determine the safety and efficacy of this intervention in both preclinical and clinical stroke studies.

G-CSF as an adjunctive therapy with umbilical cord blood cell transplantation for traumatic brain injury

Traumatic brain injury (TBI), a major contributor to deaths and permanent disability worldwide, has been recently described as a progressive cell death process rather than an acute event. TBI pathophysiology is complicated and can be distinguished by the initial primary injury and the subsequent secondary injury that ensues days after the trauma. Therapeutic opportunities for TBI remain very limited with patients subjected to surgery or rehabilitation therapy. The efficacy of stem cell-based interventions, as well as neuroprotective agents in other neurological disorders of which pathologies overlap with TBI, indicates their potential as alternative TBI treatments. Furthermore, their therapeutic limitations may be augmented when combination therapy is pursued instead of using a single agent. Indeed, we demonstrated remarkable combined efficacy of human umbilical cord blood (hUCB) cell therapy and granulocyte-colony-stimulating factor (G-CSF) treatment in TBI models, providing essential evidence for the translation of this approach to treat TBI. Further studies are warranted to determine the mechanisms underlying therapeutic benefits exerted by hUCB + G-CSF in order to enhance its safety and efficacy in the clinic.

Granulocyte colony-stimulating factor attenuates delayed tPA-induced hemorrhagic transformation in ischemic stroke rats by enhancing angiogenesis and vasculogenesis

Treatment with tissue plasminogen activator (tPA) beyond the therapeutic time window (>4.5 hours post stroke) may produce hemorrhagic transformation (HT). Strategies that could extend the narrow time window of tPA will benefit a significant number of stroke patients. Male Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAo) and given vehicle, tPA (10 mg/kg), or tPA and granulocyte colony-stimulating factor (G-CSF, 300 μg/kg), at 6 hours after MCAo. Twenty-four hours post treatment, G-CSF+tPA-treated stroke rats displayed 25% improvement in neurological functions and 38.9% reduction of hemorrhage, with Western blots showing 1.9- and 1.2-fold increments in Ang-2 expression in the ischemic cortex and striatum, respectively, and 3-fold increase in phosphorylated endothelial nitric oxide synthase expression in the ipsilateral cortex relative to tPA-treated rats. Immunohistochemistry also showed 2- and 2.8-fold increase in von-Willebrand expression, 3.2- and 2.2-fold increased CD34+ expression, and 4- and 13-fold upregulation of VEGFR-2 expression in the ischemic cortex and striatum, respectively, in G-CSF+tPA-treated stroke rats relative to tPA-treated subjects. Altogether, these findings indicate that G-CSF attenuated delayed tPA-induced HT likely via the enhancement of angiogenesis and vasculogenesis. The use of G-CSF to protect the vasculature may improve the clinical outcome of tPA even outside the currently indicated therapeutic window for ischemic stroke.

Proteomics screening of molecular targets of granulocyte colony stimulating factor in the mouse brain and PC12 cell line

AIMS

Granulocyte colony stimulating factor (G-CSF), a new neuroprotective agent, binds to its specific receptors in the brain. In this study we hypothesized that at least a part of G-CSF's neuroprotective effect may be mediated through its interaction with other proteins in the brain.

MAIN METHODS

Using an immunoprecipitation (IP) kit, at first the antibody of G-CSF was covalently crosslinked to protein A/G agarose. Then the mouse brain or PC12 cell lysate mixed with G-CSF was added to the agarose beads plus antibody. After immunoaffinity isolation of target proteins, gel electrophoresis was performed and protein bands were identified using MALDI-TOF/TOF and MASCOT software.

KEY FINDINGS

Our data show that G-CSF physically binds to cellular proteins like sodium/potassium-transporting ATPase, beta actin, aldehyde dehydrogenase, regucalcin and glutathione-s-transferase. These proteins are involved in membrane transportation, cell structure, signal transduction, enzymes involve in calcium related cell signaling and redox homeostasis.

SIGNIFICANCE

Interaction of G-CSF with these proteins can explain some of its pharmacological effects in the CNS.

Ischemic stroke and repair: current trends in research and tissue engineering treatments

Stroke, the third leading cause of mortality, is usually associated with severe disabilities, high recurrence rate and other poor outcomes. Currently, there are no long-term effective treatments for stroke. Cell and cytokine therapies have been explored previously. However, the therapeutic outcomes are often limited by poor survival of transplanted cells, uncontrolled cell differentiation, ineffective engraftment with host tissues and non-sustained delivery of growth factors. A tissue-engineering approach provides an alternative for treating ischemic stroke. The key design considerations for the tissue engineering approach include: choice of scaffold materials, choice of cells and cytokines and delivery methods. Here, we review current cell and biomaterial based therapies available for ischemic stroke, with a special focus on tissue-engineering strategies for regeneration of stroke-affected neuronal tissue.

Phase I study of intravenous low-dose granulocyte colony-stimulating factor in acute and subacute ischemic stroke

BACKGROUND

Granulocyte colony-stimulating factor (G-CSF; filgrastim) may be useful for the treatment of acute ischemic stroke because of its neuroprotective and neurogenesis-promoting properties, but an excessive increase of neutrophils may lead to brain injury. We examined the safety and tolerability of low-dose G-CSF and investigated the effectiveness of G-CSF given intravenously in the acute phase (at 24 hours) or subacute phase (at 7 days) of ischemic stroke.

METHODS

Three intravenous dose regimens (150, 300, or 450 μg/body/day, divided into 2 doses for 5 days) of G-CSF were examined in 18 patients with magnetic resonance imaging (MRI)-confirmed infarct in the territory of the middle cerebral artery. Nine patients received the first dose at 24 hours poststroke (acute group) and 9 patients received the first dose on day 7 poststroke (subacute group; n = 3 at each dose in each group). A scheduled administration of G-CSF was skipped if the patient's leukocyte count exceeded 40,000/μL. Patients received neurologic and MRI examinations.

RESULTS

We found neither serious adverse event, drug-related platelet reduction nor splenomegaly. Leukocyte levels remained below 40,000/μL at 150 and 300 μg G-CSF/body/day, but rose above 40,000/μL at 450 μg G-CSF/body/day. Neurologic function improvement between baseline and day 90 was more marked after treatment in the acute phase versus the subacute phase (Barthel index 49.4 ± 28.1 v 15.0 ± 22.0; P < .01).

CONCLUSIONS

Low-dose G-CSF (150 and 300 μg/body/day) was safe and well tolerated in ischemic stroke patients, and leukocyte levels remained below 40,000/μL.

Stem cell therapy for cerebral ischemia: from basic science to clinical applications

Recent stem cell technology provides a strong therapeutic potential not only for acute ischemic stroke but also for chronic progressive neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis with neuroregenerative neural cell replenishment and replacement. In addition to resident neural stem cell activation in the brain by neurotrophic factors, bone marrow stem cells (BMSCs) can be mobilized by granulocyte-colony stimulating factor for homing into the brain for both neurorepair and neuroregeneration in acute stroke and neurodegenerative diseases in both basic science and clinical settings. Exogenous stem cell transplantation is also emerging into a clinical scene from bench side experiments. Early clinical trials of intravenous transplantation of autologous BMSCs are showing safe and effective results in stroke patients. Further basic sciences of stem cell therapy on a neurovascular unit and neuroregeneration, and further clinical advancements on scaffold technology for supporting stem cells and stem cell tracking technology such as magnetic resonance imaging, single photon emission tomography or optical imaging with near-infrared could allow stem cell therapy to be applied in daily clinical applications in the near future.

Growth factors in ischemic stroke

Data from pre-clinical and clinical studies provide evidence that colony-stimulating factors (CSFs) and other growth factors (GFs) can improve stroke outcome by reducing stroke damage through their anti-apoptotic and anti-inflammatory effects, and by promoting angiogenesis and neurogenesis. This review provides a critical and up-to-date literature review on CSF use in stroke. We searched for experimental and clinical studies on haemopoietic GFs such as granulocyte CSF, erythropoietin, granulocyte-macrophage colony-stimulating factor, stem cell factor (SCF), vascular endothelial GF, stromal cell-derived factor-1α and SCF in ischemic stroke. We also considered studies on insulin-like growth factor-1 and neurotrophins. Despite promising results from animal models, the lack of data in human beings hampers efficacy assessments of GFs on stroke outcome. We provide a comprehensive and critical view of the present knowledge about GFs and stroke, and an overview of ongoing and future prospects.

The activation of β2-adrenergic receptors in naïve rats causes a reduction of blood glutamate levels: relevance to stress and neuroprotection

This study examines the effects of the activation of β1 and β2-adrenergic receptors on glutamate homeostasis in the blood of naïve rats. Forty five male Sprague-Dawley rats were randomly assigned into one of seven treatment groups that were treated with various β-adrenergic receptor agonist and antagonist drugs. Blood glutamate levels were determined at t = 0, 30, 60, 90, and 120 min. The activation of β1 and β2-adrenergic receptors via isoproterenol hydrochloride administration produced a marked sustained decrease in blood glutamate levels by 60 min after treatment (ANOVA, t = 60, 90 min: P < 0.05, t = 120 min: P < 0.01). Pretreatment with propranolol hydrochloride (a non-selective β-adrenergic receptor blocker) or butaxamine hydrochloride (a selective β2-adrenergic receptor blocker) occluded the isoproterenol-mediated decrease in blood glutamate levels. Propranolol alone had no effect on blood glutamate levels. Selective β1-adrenergic receptor blockade with metoprolol resulted in decreased blood glutamate levels (ANOVA, t = 90 min: P < 0.05, t = 120 min: P < 0.01). Butaxamine hydrochloride alone resulted in a delayed-onset increase in glutamate levels (ANOVA, t = 120 min: P < 0.05). The results suggest that the activation of β2 receptors plays an important role in the homeostasis of glutamate in rat blood.

G-CSF, rt-PA and combination therapy after experimental thromboembolic stroke

Background

Granulocyte Colony-Stimulating Factor (G-CSF) has remarkable neuroprotective properties. Due to its proven safety profile, G-CSF is currently used in clinical stroke trials. As neuroprotectants are considered to be more effective in the early phase of cerebral ischemia and during reperfusion, G-CSF should to be tested in combination with thrombolysis. Therefore, combination therapy was investigated in an experimental model of thromboembolic stroke.

Methods

Male Wistar rats (n = 72) were subjected to a model of thromboembolic occlusion (TE) of the middle cerebral artery. Different groups (n = 12 each) treated by recombinant tissue-plasminogen activator (rt-PA) or/and G-CSF: group control (control), group early G-CSF (G-CSF 60 min after TE), group rt-PA (rt-PA 60 min after TE), group com (combination rt-PA/G-CSF), group delayed rt-PA (rt-PA after 180 min), group deco (G-CSF after 60 min, rt-PA after 180 min). Animals were investigated by magnetic resonance imaging (MRI) and silver infarct staining (SIS) 24 hours after TE.

Results

Early G-CSF or rt-PA reduced the infarct size compared to all groups (p < 0.05 to p < 0.01) with the exception of group com, (p = n.s.) as measured by T2, DWI, and SIS. Late administration of rt-PA lead to high mortality and larger infarcts compared to all other groups (p < 0.05 to p < 0.01). Pre-treatment by G-CSF (deco) reduced infarct site compared to delayed rt-PA treatment (p < 0.05). G-CSF did not significantly influence PWI when combined with rt-PA. All animals treated by rt-PA showed improved parameters in PWI indicating reperfusion.

Conclusions

G-CSF was neuroprotective when given early after TE. Early combination with rt-PA showed no additional benefit compared to rt-PA or G-CSF alone, but did not lead to side effects. Pretreatment by G-CSF was able to reduce deleterious effects of late rt-PA treatment.

Targeting ischemic penumbra: part I - from pathophysiology to therapeutic strategy

Penumbra is the viable tissue around the irreversibly damaged ischemic core. The purpose of acute stroke treatment is to salvage penumbral tissue and to improve brain function. However, the majority of acute stroke patients who have treatable penumbra are left untreated. Therefore, developing an effective non-recanalizational therapeutics, such as neuroprotective agents, has significant clinical applications. Part I of this serial review on "targeting penumbra" puts special emphases on penumbral pathophysiology and the development of therapeutic strategies. Bioenergetic intervention by massive metabolic suppression and direct energy delivery would be a promising future direction. An effective drug delivery system for this purpose should be able to penetrate BBB and achieve high local tissue drug levels while non-ischemic region being largely unaffected. Selective drug delivery to ischemic stroke penumbra is feasible and deserves intensive research.

Suppressive effects of intrathecal granulocyte colony-stimulating factor on excessive release of excitatory amino acids in the spinal cerebrospinal fluid of rats with cord ischemia: role of glutamate transporters

Recently, the hematopoietic factor, granulocyte colony-stimulating factor (G-CSF), has been shown to exhibit neuroprotective effects in CNS injuries. Our previous study demonstrated that intrathecal (i.t.) G-CSF significantly improved neurological defects in spinal cord ischemic rats. Considerable evidence indicates that the release of excessive amounts of excitatory amino acids (EAAs) plays a critical role in neuron injury induced by ischemic insult. In the present study, we used a spinal cord ischemia-microdialysis model to examine whether i.t. G-CSF exerted antiexcitotoxicity effects in a rat model of spinal cord ischemia. I.t. catheters and a microdialysis probe were implanted in male Wistar rats. The results revealed that spinal cord ischemia-induced neurological defects were accompanied by a significant increase in the concentration of EAAs (aspartate and glutamate) in the spinal dialysates from 30 min to 2 days after reperfusion. I.t administration of G-CSF immediately after the performance of surgery designed to induce ischemia led to a significant reduction in ischemia-induced increases in the levels of spinal EAAs. Moreover, i.t. G-CSF also brought about a significant reduction in the elevation of spinal EAA concentrations induced by exogenous i.t. administration of glutamate (10 microl of 500 mM). I.t. G-CSF attenuated spinal cord ischemia-induced downregulation of expression of three glutamate transporters (GTs), glial transporter Glu-Asp transporter (GLAST), Glu transporter-1 (GLT-1), and excitatory amino acid carrier 1 (EAAC1) protein 48 h after spinal cord ischemic surgery. Immunohistofluorescent staining showed that i.t. G-CSF significantly upregulated expression of the three GTs in the gray matter of the lumbar spinal cord from 3 to 24 h after injection. We propose that i.t. G-CSF possesses an ability to reduce the extent of spinal cord ischemia-induced excitotoxicity by inducing the expression of glutamate transporters.

Granulocyte-colony stimulating factor in experimental stroke and its effects on infarct size and functional outcome: A systematic review

BACKGROUND

Granulocyte-colony stimulating factor (G-CSF) shows promise as a treatment for stroke. This systematic review assesses G-CSF in experimental ischaemic stroke.

METHODS

Relevant studies were identified with searches of Medline, Embase and PubMed. Data were extracted on stroke lesion size, neurological outcome and quality, and analysed using Cochrane Review Manager using random effects models; results are expressed as standardised mean difference (SMD) and odds ratio (OR).

RESULTS

Data were included from 19 publications incorporating 666 animals. G-CSF reduced lesion size significantly in transient (SMD -1.63, p<0.00001) but not permanent (SMD -1.56, p=0.11) focal models of ischaemia. Lesion size was reduced at all doses and with treatment commenced within 4 h of transient ischaemia. Neurological deficit (SMD -1.37, p=0.0004) and limb placement (SMD -1.88, p=0.003) improved with G-CSF; however, locomotor activity (> or =4 weeks post-ischaemia) was not (SMD 0.76, p=0.35). Death (OR 0.27, p<0.0001) was reduced with G-CSF. Median study quality was 4 (range 0-7/8); Egger's test suggested significant publication bias (p<0.001).

CONCLUSIONS

G-CSF significantly reduced lesion size in transient but not permanent models of ischaemic stroke. Motor impairment and death were also reduced. Further studies assessing dose response, administration time, length of ischaemia and long-term functional recovery are needed.