Granulocyte colony-stimulating factor induces sensorimotor recovery in intracerebral hemorrhage

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

We investigated the ability of granulocyte-colony stimulating factor (G-CSF) on inhibiting glutamate release by microdialysis in a rat stroke model. Male Wistar rats (n=15) were treated with either intravenous saline or G-CSF (60 microg/kg) 30 min after temporary middle cerebral artery occlusion (MCAO). G-CSF significantly attenuated the release of glutamate in the infarcted striatum from 30 minutes to 180 minutes after tMCAO compared with control (p<0.05). Infarct volume in G-CSF treated group (135+/-13 mm(3)) reduced significantly compared to control (181+/-10mm(3)) at 24 hours after tMCAO. The result of present study show that G-CSF possess an ability to inhibit excitotoxicity after ischemic stroke.

Advances in hemorrhagic stroke therapy: conventional and novel approaches

Treatments for spontaneous intracerebral, thrombolytic-induced and intraventricular hemorrhages (IVH) are still at the preclinical or early clinical investigational stages. There has been some renewed interest in the use of surgical evacuation surgery or thrombolytics to remove hematomas, but these techniques can be used only for specific types of brain bleeding. The STICH (Surgical Trial in Intracerebral Haemorrhage) clinical trials should provide some insight into the potential for such techniques to counteract hematoma-induced damage and subsequently, morbidity and mortality. More recently, clinical trials (ATACH [Antihypertensive Treatment in Acute Cerebral Hemorrhage] and INTERACT [Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial]) have begun testing whether or not regulating blood pressure affects the well-being of hemorrhage patients, but the findings thus far have not conclusively demonstrated a positive result. More promising trials, such as the early stage CHANT (Cerebral Hemorrhagic And NXY-059 Treatment) and the late stage FAST (Factor VIIa for Acute Hemorrhagic Stroke Treatment), have addressed whether or not manipulating oxidative stress and components of the blood coagulation cascade can achieve an improved prognosis following spontaneous hemorrhages. However, CHANT was halted prematurely because although it showed that the spin trap agent NXY-059 was safe, it also demonstrated that the drug was ineffective in treating acute ischemic stroke. In addition, the recombinant activated factor VII FAST trial recently concluded with only modestly positive results. Despite a beneficial effect on the primary end point of reducing hemorrhage volume, controlling the coagulation cascade with recombinant factor VIIa did not decrease the mortality rate. Consequently, Novo Nordisk has abandoned further development of the drug for the treatment of intracerebral hemorrhaging. Even though progress in hemorrhage therapy that successfully reduces the escalating morbidity and mortality rate associated with brain bleeding is slow, perseverance and applied translational drug development will eventually be productive. The urgent need for such therapy becomes more evident in light of concerns related to uncontrolled high blood pressure in the general population, increased use of blood thinners by the elderly (e.g., warfarin) and thrombolytics by acute ischemic stroke patients, respectively. The future of drug development for hemorrhage may require a multifaceted approach, such as combining drugs with diverse mechanisms of action. Because of the substantial benefit of factor VIIa in reducing hemorrhage volume, it should be considered as a prime drug candidate included in combination therapy as an off-label use if the FAST trial proves that the risk of thromboembolic events is not increased with drug administration. Other promising drugs that may be considered in combination include uncompetitive NMDA receptor antagonists (such as memantine), antioxidants, metalloprotease inhibitors, statins and erythropoietin analogs, all of which have been shown to reduce hemorrhage and behavioral deficits in one or more animal models.

Colony stimulating factors (including erythropoietin, granulocyte colony stimulating factor and analogues) for stroke

BACKGROUND

Colony stimulating factors (CSFs), also called haematopoietic growth factors, regulate bone marrow production of circulating red and white cells, and platelets. They have been shown to be neuroprotective in experimental stroke. Some CSFs also mobilise the release of bone marrow stem cells into the circulation.

OBJECTIVES

To assess the effects of CSFs on functional outcome and haematology measures in patients with acute or subacute stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched November 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2006), MEDLINE (1985 to June 2006), EMBASE (1985 to June 2006), and Science Citation Index (1985 to June 2006). In an attempt to identify further published, unpublished and ongoing trials we contacted manufacturers and principal investigators of trials (last contacted 2006). We also searched reference lists of relevant articles and reviews.

SELECTION CRITERIA

Unconfounded randomised controlled trials recruiting patients with acute or subacute ischaemic or haemorrhagic stroke were included. CSFs included stem cell factor (SCF), erythropoietin (EPO), granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), macrophage-colony stimulating factor (M-CSF, CSF-1), and thrombopoietin (TPO), or analogues of these. The primary outcome was functional outcome (assessed as combined death or disability and dependency using scales such as the modified Rankin Scale or Barthel Index) at the end of the trial. Secondary outcomes included safety at the end of treatment (death, impairment, deterioration, extension or recurrence), death at the end of follow up, and haematology measures (blood counts at or around day seven after treatment commenced).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality. Study authors were contacted for additional information.

MAIN RESULTS

No large trials were identified. EPO therapy was associated with a non-significant reduction in neurological impairment in one small trial (n = 40 participants) but had no significant effect on haematological measures. G-CSF was associated with a non-significant reduction in combined death and dependency in two small trials (n = 46 participants) although there was substantial heterogeneity in this result. G-CSF significantly elevated white cell count in three trials (n = 91). Further small trials of EPO and G-CSF are ongoing.

AUTHORS' CONCLUSIONS

No large trials of EPO, G-CSF or other colony stimulating factors have been performed and it is too early to know whether CSFs improve functional outcome.

Valproic acid-mediated neuroprotection in intracerebral hemorrhage via histone deacetylase inhibition and transcriptional activation

The modification of histone N-terminal tails by acetylation or deacetylation can alter the interaction between histones and DNA, and thus regulate gene expression. Recent experiments have demonstrated that valproic acid (VPA), a well-known anti-epileptic drug, can directly inhibit histone deacetylase (HDAC) activity and cause the hyperacetylation of histones. Moreover, VPA has been shown to mediate neuronal protection by activating signal transduction pathways and by inhibiting proapoptotic factors. In this study, we attempted to determine whether VPA alleviates cerebral inflammation and perihematomal cell death after intracerebral hemorrhage (ICH). Adult male rats received intraperitoneal injections of 300 mg/kg VPA or PBS twice a day after ICH induction. VPA treatment inhibited hematoma expansion, perihematomal cell death, caspase activities, and inflammatory cell infiltration. In addition, VPA treatment had the following expressional effects; it activated the translations of acetylated histone H3, pERK, pAKT, pCREB, and HSP70; up-regulated bcl-2 and bcl-xl but down-regulated bax; and down-regulated the mRNAs of Fas-L, IL-6, MMP-9, MIP-1, MCP-1, and tPA. VPA-treated rats also showed better functional recovery from 1 day to 4 weeks after ICH. Here we show that VPA induces neuroprotection in a murine ICH model and that its neuroprotective effects are mediated by transcriptional activation following HDAC inhibition.

Decreased focal inflammatory response by G-CSF may improve stroke outcome after transient middle cerebral artery occlusion in rats

Recent studies have shown that administration of granulocyte colony-stimulating factor (G-CSF) is neuroprotective. However, the precise mechanisms of the neuroprotective effect of G-CSF are not entirely known. We carried out 90-min transient middle cerebral occlusion (tMCAO) of rats. The rats were injected with vehicle or G-CSF (50 mug/kg) immediately after reperfusion and sacrificed 8, 24, or 72 hr later. 2,3,5-Triphenyltetrazolium chloride (TTC) staining was carried out using brain sections of 72 hr, and immunohistochemistry was carried out with those of 8, 24, and 72 hr. TTC-staining showed a significant reduction of infarct volume in the G-CSF-treated group (**P < 0.01). Immunohistochemistry showed a significant decrease of the number of cells expressing tumor necrosis factor-alpha (TNF-alpha) at 8-72 hr, transforming growth factor-beta (TGF-beta) and inducible nitric oxide synthase (iNOS) at 24 and 72 hr after tMCAO in the peri-ischemic area (*P < 0.05 each). Our data suggest that the suppression of inflammatory cytokines and iNOS expression may be one mechanism of neuroprotection by G-CSF.

Anti-apoptotic effect of granulocyte-colony stimulating factor after focal cerebral ischemia in the rat

We investigated the molecular mechanisms of the anti-apoptotic properties of granulocyte-colony stimulating factor (G-CSF) on neurons and whether G-CSF affects glial cell survival following focal cerebral ischemia in rats. Sprague-Dawley rats were subjected to a transient 90 min middle cerebral artery occlusion (MCAO) by the intraluminal occlusion technique. Rats were treated with either a single dose of G-CSF (50 microg/kg, s.c.) at the onset of reperfusion or G-CSF (50 microg/kg body weight, s.c.) was administered starting at the onset of reperfusion and followed by the administration of the same dose per day for an additional 2 days. Brains were harvested either 24 h, 72 h or 2 weeks after reperfusion for assays of infarct volume, immunohistological studies and Western blot analysis for phosphorylated signal transducer and activator of transcription 3 (pSTAT3), Pim-1, bcl-2, Bax, cytochrome c, cellular inhibitor of apoptosis protein 2 (cIAP2), and cleaved caspase-3 levels. G-CSF significantly reduced infarct volume and ameliorated the early neurological outcome. G-CSF treatment significantly up-regulated pSTAT3, Pim-1, bcl-2 expression, and down-regulated cytochrome c release to the cytosol, Bax translocation to the mitochondria, and cleaved caspase-3 levels in neurons. The activation of the STAT3 pathway was accompanied by increased cIAP2 expression in glial cells. After MCAO, G-CSF treatment increased both neuronal and glial survival by effecting different anti-apoptotic pathways which reflects the multifactorial actions of this drug. These changes were associated with remarkable improvement in tissue preservation and behavioral outcome.

Granulocyte-colony-stimulating factor mobilizes bone marrow stem cells in patients with subacute ischemic stroke: the Stem cell Trial of recovery EnhanceMent after Stroke (STEMS) pilot randomized, controlled trial (ISRCTN 16784092)

BACKGROUND AND PURPOSE

Loss of motor function is common after stroke and leads to significant chronic disability. Stem cells are capable of self-renewal and of differentiating into multiple cell types, including neurones, glia, and vascular cells. We assessed the safety of granulocyte-colony-stimulating factor (G-CSF) after stroke and its effect on circulating CD34+ stem cells.

METHODS

We performed a 2-center, dose-escalation, double-blind, randomized, placebo-controlled pilot trial (ISRCTN 16784092) of G-CSF (6 blocks of 1 to 10 microg/kg SC, 1 or 5 daily doses) in 36 patients with recent ischemic stroke. Circulating CD34+ stem cells were measured by flow cytometry; blood counts and measures of safety and functional outcome were also monitored. All measures were made blinded to treatment.

RESULTS

Thirty-six patients, whose mean+/-SD age was 76+/-8 years and of whom 50% were male, were recruited. G-CSF (5 days of 10 microg/kg) increased CD34+ count in a dose-dependent manner, from 2.5 to 37.7 at day 5 (area under curve, P=0.005). A dose-dependent rise in white cell count (P<0.001) was also seen. There was no difference between treatment groups in the number of patients with serious adverse events: G-CSF, 7/24 (29%) versus placebo 3/12 (25%), or in their dependence (modified Rankin Scale, median 4, interquartile range, 3 to 5) at 90 days.

CONCLUSIONS

G-CSF is effective at mobilizing bone marrow CD34+ stem cells in patients with recent ischemic stroke. Administration is feasible and appears to be safe and well tolerated. The fate of mobilized cells and their effect on functional outcome remain to be determined.

Granulocyte colony-stimulating factor does not affect contusion size, brain edema or cerebrospinal fluid glutamate concentrations in rats following controlled cortical impact

INTRODUCTION

Granulocyte colony-stimulating factor (G-CSF) is an established treatment in the neutropenic host. Usage in head-injured patients at risk for infection may aggravate brain damage. In contrast, evidence of G-CSF neuroprotective effects has been reported in rodent models of focal cerebral ischemia. We investigated effects of G-CSF in acute focal traumatic brain injury (TBI) in rats.

METHODS

Thirty-six male Sprague-Dawley rats were anesthetized with 1.2%) to 2.0% isoflurane and subjected to controlled cortical impact injury (CCII). Thirty minutes following CCII, either vehicle or G-CSF was administered intravenously. Animals were sacrificed 24 hours following CCII. Glutamate concentrations were determined in cisternal cerebrospinal fluid (CSF). Brain edema was assessed gravimetrically. Contusion size was estimated by 2,3,5-triphenyltetrazolium chloride staining and volumetric analysis.

RESULTS

Dose-dependent leukocytosis was induced by infusion of G-CSF. Physiological variables were unaffected. Water content of the traumatized hemisphere and CSF glutamate concentrations were unchanged by treatment. Contusion volume was similar in all groups.

CONCLUSIONS

A single injection of G-CSF did not influence cortical contusion volume, brain edema, or glutamate concentrations in CSF determined 24 hours following CCII in rats. G-CSF, administered 30 minutes following experimental TBI, failed to exert neuroprotective effects.

Erythropoietin reduces perihematomal inflammation and cell death with eNOS and STAT3 activations in experimental intracerebral hemorrhage

Erythropoietin (EPO), a pleiotropic cytokine involved in erythropoiesis, is tissue-protective in ischemic, traumatic, toxic and inflammatory injuries. In this study, we investigated the effect of EPO in experimental intracerebral hemorrhage (ICH). Two hours after inducing ICH via the stereotaxic infusion of collagenase, recombinant human EPO (500 or 5000 IU/kg, ICH + EPO group) or PBS (ICH + vehicle group) was administered intraperitoneally, then once daily afterwards for 1 or 3 days. ICH + EPO showed the better functional recovery in both rotarod and modified limb placing tests. The brain water content was decreased in ICH + EPO dose-dependently, as compared with ICH + vehicle. The effect of EPO on the brain water content was inhibited by N(omega)-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 10 mg/kg). Mean hemorrhage volume was also decreased in ICH + EPO. EPO reduced the numbers of TUNEL +, myeloperoxidase + or OX-42 + cells in the perihematomal area. In addition, EPO reduced the mRNA level of TNF-alpha, Fas and Fas-L, as well as the activities of caspase-8, 9 and 3. EPO treatment showed up-regulations of endothelial nitric oxide synthase (eNOS) and p-eNOS, pAkt, pSTAT3 and pERK levels. These data suggests that EPO treatment in ICH induces better functional recovery with reducing perihematomal inflammation and apoptosis, coupled with activations of eNOS, STAT3 and ERK.

Memantine reduces hematoma expansion in experimental intracerebral hemorrhage, resulting in functional improvement

Glutamate is accumulated in abundance during the early period of experimental hematoma, and the activation of N-methyl-D-aspartate (NMDA) receptors by glutamate can result in an influx of calcium and neuronal death in cases of intracerebral hemorrhage (ICH). Memantine, which is known to be a moderate-affinity, uncompetitive, NMDA receptor antagonist, was investigated with regard to its ability to block the glutamate overstimulation and tissue plasminogen activator (tPA)/urokinase plasminogen activator (uPA)/matrix metalloproteinase (MMP)-9 modulation in experimental ICH. Intracerebral hemorrhage was induced via the infusion of collagenase into the left basal ganglia of adult rats. Either memantine (20 mg/kg/day) or PBS was intraperitoneally administered 30 min after the induction of ICH, and, at daily intervals afterwards, for either 3 or 14 days. Hemorrhage volume decreased by 47% in the memantine group, as compared with the ICH-only group. In the memantine group, the numbers of TUNEL+, myeloperoxidase (MPO)+, and OX42+ cells decreased in the periphery of the hematoma. Memantine resulted in an upregulation of bcl-2 expression and an inhibition of caspase-3 activation. Memantine also exerted a profound inhibitory effect on the upregulation of tPA/uPA mRNA, and finally decreased the MMP-9 level in the hemorrhagic brain. In modified limb-placing test, the memantine-treated rats exhibited lower scores initially, and recovered more quickly and thoroughly throughout the 35 days of the study. Here, we show that memantine causes a reduction of hematoma expansion, coupled with an inhibitory effect on the tPA/uPA and MMP-9 level. Subsequently, memantine was found to reduce inflammatory infiltration and apoptosis, and was also determined to induce functional recovery after ICH.

Systemic application of granulocyte-colony stimulating factor and stem cell factor exacerbates excitotoxic brain injury in newborn mice

Granulocyte-colony stimulating factor (G-CSF) has been shown to reduce brain lesion size and mortality in adult mice after hypoxic-ischemic injury. Another hematopoietic growth factor, stem cell factor (SCF), has been shown to be up-regulated in the brains of adult rodents following brain damage, where it stimulates postlesional neurogenesis. Injection of the excitotoxic agent ibotenate into the brain of newborn mice produces a brain lesion characterized by neuronal death and white matter cysts, which is similar to periventricular leucomalacia. The aim of the present study was to investigate whether administration of SCF and G-CSF is neuroprotective against ibotenate lesions in neonatal mice. Contrary to our expectations, cortical and white matter brain lesions induced by ibotenate were enhanced following the administration of 50 microg/kg SCF or 200 microg/kg G-CSF. Dose-response studies indicated that G-CSF could increase grey matter lesions even at lower dosages (22 and 66 microg/kg). Administration of SCF and G-CSF in combination also increased cortical and white matter lesions, to 133 +/- 8% and 187 +/- 12%. In the undamaged brain, G-CSF or G-CSF+SCF treatment had no effect on apoptosis in the grey or white matter; however, these treatments significantly increased apoptosis in the damaged brain. Our data clearly demonstrate that G-CSF and SCF are not neuroprotective and result in deleterious enhancement of excitotoxic brain damage in newborn mice. We conclude that G-CSF and SCF should be used cautiously in newborn infants with brain lesions; if they are used, long term neurologic and neurodevelopmental follow-up is warranted.

A novel neuroprotectant granulocyte-colony stimulating factor

BACKGROUND AND PURPOSE

Granulocyte-colony stimulating factor (G-CSF) is a growth factor that orchestrates the proliferation, differentiation, and survival of hematopoietic progenitor cells. It has been used for many years in clinical practice to accelerate the recovery of patients from neutropenia after cytotoxic therapy. However, there is a growing body of evidence from experimental studies suggesting that G-CSF also has important nonhematopoietic functions in the central nervous system.

SUMMARY OF REVIEW

The presence of the G-CSF/G-CSF-receptor system in the brain and its role in neuroprotection and neural tissue repair has been investigated in many recent studies. The neuroprotective actions of G-CSF have mainly been attributed to its anti-inflammatory and antiapoptotic effects. Furthermore, it induces neurogenesis and angiogenesis and improves functional recovery. In this review, we summarize the role of G-CSF and the corresponding signal transduction pathways regulated by G-CSF in neuroprotection.

CONCLUSIONS

Much additional work is needed to better understand the precise mechanisms of G-CSF-induced neuroprotection. However, there is emerging data suggesting that G-CSF is a potential new agent for neuroprotection.

Granulocyte colony-stimulating factor enhances angiogenesis after focal cerebral ischemia

Granulocyte colony-stimulating factor (G-CSF) is a neuroprotective agent and activates endothelial proliferation and bone marrow stem cell mobilization. We studied the effect of G-CSF on angiogenesis and neurological recovery after focal cerebral ischemia. After the induction of transient focal ischemia in rats, G-CSF (50 micro/day, i.p.) or PBS was administered for 3 days. We evaluated the functional recovery, infarct volume, inflammatory infiltration, blood-brain barrier (BBB) disruption, hemispheric atrophy, protein expressions of endothelial nitric oxide synthase (eNOS) and angiopoietins, and the therapeutic time window of G-CSF administration. We then analyzed endothelial cell proliferation, the vascular surface area, the number of branch points, and the vascular length. G-CSF treatment improved behavioral recovery and reduced the infarct volume, the inflammatory infiltration, the BBB disruption, and the hemispheric atrophy. G-CSF injection, starting at 2 h, 1 day, or 4 days after ischemia, resulted in a better functional recovery and a greater reduction in hemispheric atrophy than injection starting at day 7. The vascular surface area, the vascular branch points, the vascular length, the number of BrdU(+) endothelial cells, and eNOS/angiopoietin-2 expression were significantly increased in the G-CSF group compared with the ischemia-only group. G-CSF injection starting at 1 day induced larger endothelial proliferation compared with injection starting at 7 days. In this study, we provide evidences that G-CSF enhances the angiogenesis and reduces the ischemic damage, which promotes the long-term functional recovery.