Granulocyte stimulating factor attenuates hypoxic-ischemic brain injury by inhibiting apoptosis in neonatal rats

The role of G-CSF neuroprotective effects in neonatal hypoxic-ischemic encephalopathy (HIE): current status

Hypoxic-ischemic encephalopathy (HIE) is an important cause of permanent damage to central nervous system (CNS) that may result in neonatal death or manifest later as mental retardation, epilepsy, cerebral palsy, or developmental delay. The primary cause of this condition is systemic hypoxemia and/or reduced cerebral blood flow with long-lasting neurological disabilities and neurodevelopmental impairment in neonates. About 20 to 25% of infants with HIE die in the neonatal period, and 25-30% of survivors are left with permanent neurodevelopmental abnormalities. The mechanisms of hypoxia-ischemia (HI) include activation and/or stimulation of myriad of cascades such as increased excitotoxicity, oxidative stress, N-methyl-D-aspartic acid (NMDA) receptor hyperexcitability, mitochondrial collapse, inflammation, cell swelling, impaired maturation, and loss of trophic support. Different therapeutic modalities have been implicated in managing neonatal HIE, though translation of most of these regimens into clinical practices is still limited. Therapeutic hypothermia, for instance, is the most widely used standard treatment in neonates with HIE as studies have shown that it can inhibit many steps in the excito-oxidative cascade including secondary energy failure, increases in brain lactic acid, glutamate, and nitric oxide concentration. Granulocyte-colony stimulating factor (G-CSF) is a glycoprotein that has been implicated in stimulation of cell survival, proliferation, and function of neutrophil precursors and mature neutrophils. Extensive studies both in vivo and ex vivo have shown the neuroprotective effect of G-CSF in neurodegenerative diseases and neonatal brain damage via inhibition of apoptosis and inflammation. Yet, there are still few experimentation models of neonatal HIE and G-CSF's effectiveness, and extrapolation of adult stroke models is challenging because of the evolving brain. Here, we review current studies and/or researches of G-CSF's crucial role in regulating these cytokines and apoptotic mediators triggered following neonatal brain injury, as well as driving neurogenesis and angiogenesis post-HI insults.

The impact of trophic and immunomodulatory factors on oligodendrocyte maturation: Potential treatments for encephalopathy of prematurity

Encephalopathy of prematurity (EoP) is a major cause of morbidity in preterm neonates, causing neurodevelopmental adversities that can lead to lifelong impairments. Preterm birth-related insults, such as cerebral oxygen fluctuations and perinatal inflammation, are believed to negatively impact brain development, leading to a range of brain abnormalities. Diffuse white matter injury is a major hallmark of EoP and characterized by widespread hypomyelination, the result of disturbances in oligodendrocyte lineage development. At present, there are no treatment options available, despite the enormous burden of EoP on patients, their families, and society. Over the years, research in the field of neonatal brain injury and other white matter pathologies has led to the identification of several promising trophic factors and cytokines that contribute to the survival and maturation of oligodendrocytes, and/or dampening neuroinflammation. In this review, we discuss the current literature on selected factors and their therapeutic potential to combat EoP, covering a wide range of in vitro, preclinical and clinical studies. Furthermore, we offer a future perspective on the translatability of these factors into clinical practice.

Short-, Mid-, and Long-Term Effect of Granulocyte Colony-Stimulating Factor/Stem Cell Factor and Fms-Related Tyrosine Kinase 3 Ligand Evaluated in an In Vivo Model of Hypoxic-Hyperoxic Ischemic Neonatal Brain Injury

Hematopoietic growth factors are considered to bear neuroprotective potential. We have previously shown that delayed treatment with granulocyte colony-stimulating factor (G-CSF)/stem cell factor (SCF) and Fms-related tyrosine kinase 3 ligand (FL) ameliorates excitotoxic neonatal brain injury. The effect of these substances in combined-stressor neonatal brain injury models more closely mimicking clinical conditions has not been investigated. The aim of this study was to assess the short-, mid-, and long-term neuroprotective potential of G-CSF/SCF and FL in a neonatal model of hypoxic-hyperoxic ischemic brain injury. Five-day-old (P5) CD-1 mice were subjected to unilateral common carotid artery ligation and subsequent alternating periods of hypoxia and hyperoxia for 65 minutes. Sixty hours after injury, pups were randomly assigned to intraperitoneal treatment with (i) G-CSF (200 μg/kg)/SCF (50 μg/kg), (ii) FL (100 μg/kg), or (iii) vehicle every 24 hours for three or five consecutive days. Histopathological and functional outcomes were evaluated on P10, P18, and P90. Baseline outcome parameters were established in sham-treated and healthy control animals. Gross brain injury did not significantly differ between treatment groups at any time point. On P10, caspase-3 activation and caspase-independent apoptosis were similar between treatment groups; cell proliferation and the number of BrdU-positive vessels did not differ on P18 or P90. Neurobehavioral assessment did not reveal significant differences between treatment groups in accelerod performance, open field behavior, or novel object recognition capacity on P90. Turning behavior was more frequently observed in G-CSF/SCF- and FL-treated animals. No sex-specific differences were detected in any outcome parameter evaluated. In hypoxic-hyperoxic ischemic neonatal brain injury, G-CSF/SCF and FL treatment does not convey neuroprotection. Prior to potential clinical use, meticulous assessment of these hematopoietic growth factors is mandated.

Emergent Prophylactic, Reparative and Restorative Brain Interventions for Infants Born Preterm With Cerebral Palsy

Worldwide, an estimated 15 million babies are born preterm (<37 weeks' gestation) every year. Despite significant improvements in survival rates, preterm infants often face a lifetime of neurodevelopmental disability including cognitive, behavioral, and motor impairments. Indeed, prematurity remains the largest risk factor for the development of cerebral palsy. The developing brain of the preterm infant is particularly fragile; preterm babies exhibit varying severities of cerebral palsy arising from reductions in both cerebral white and gray matter volumes, as well as altered brain microstructure and connectivity. Current intensive care therapies aim to optimize cardiovascular and respiratory function to protect the brain from injury by preserving oxygenation and blood flow. If a brain injury does occur, definitive diagnosis of cerebral palsy in the first few hours and weeks of life is difficult, especially when the lesions are subtle and not apparent on cranial ultrasound. However, early diagnosis of mildly affected infants is critical, because these are the patients most likely to respond to emergent treatments inducing neuroplasticity via high-intensity motor training programs and regenerative therapies involving stem cells. A current controversy is whether to test universal treatment in all infants at risk of brain injury, accepting that some patients never required treatment, because the perceived potential benefits outweigh the risk of harm. Versus, waiting for a diagnosis before commencing targeted treatment for infants with a brain injury, and potentially missing the therapeutic window. In this review, we discuss the emerging prophylactic, reparative, and restorative brain interventions for infants born preterm, who are at high risk of developing cerebral palsy. We examine the current evidence, considering the timing of the intervention with relation to the proposed mechanism/s of action. Finally, we consider the development of novel markers of preterm brain injury, which will undoubtedly lead to improved diagnostic and prognostic capability, and more accurate instruments to assess the efficacy of emerging interventions for this most vulnerable group of infants.

Promoting neuroregeneration after perinatal arterial ischemic stroke: neurotrophic factors and mesenchymal stem cells

Newborns suffering from perinatal arterial ischemic stroke (PAIS) are at risk of neurodevelopmental problems. Current treatment options for PAIS are limited and mainly focus on supportive care, as presentation of PAIS is beyond the time window of current treatment strategies. Therefore, recent focus has shifted to interventions that stimulate regeneration of damaged brain tissue. From animal models, it is known that the brain increases its neurogenic capability after ischemic injury, by promoting neural cell proliferation and differentiation. However, neurogenesis is not maintained at the long term, which consequently impedes full repair leading to adverse consequences later in life. Boosting neuroregeneration of the newborn brain using treatment with neurotrophic factors and/or mesenchymal stem cells (MSCs) may be promising novel therapeutic strategies to improve neurological prospects and quality of life of infants with PAIS. This review focuses on effectiveness of neurotrophic growth factors, including erythropoietin, brain-derived neurotrophic factor, vascular endothelial growth factor, glial-derived neurotrophic factor, and MSC therapy, in both experimental neonatal stroke studies and first clinical trials for neonatal ischemic brain injury.

Downregulation of liver-intestine cadherin enhances cisplatin-induced apoptosis in human gastric cancer BGC823 cells

Gastric cancer is the fourth most common type of cancer. Liver-intestine cadherin (CDH17) has been found to be involved in the proliferation and apoptosis of gastric cancer cells. Cisplatin is one of the most widely used antineoplastic agents in the treatment of solid tumor and hematological malignancies. However, the mechanism of enhancing cisplatin-inducing effects on human gastric cancer BGC823 cells by blocking CDH17 gene, both in vitro and in vivo, remains to be clarified. In this study, we investigated the signaling pathway by which cisplatin induces apoptosis by blocking CDH17 gene in gastric cancer BGC823 cells. Our results indicate that down-expression of CDH17 gene can enhance apoptosis-inducing effects of cisplatin on human gastric cancer BGC823 cells. The expression levels of Bax and Cyt-c proteins were upregulated, but the expression levels of Bcl-2 and Bcl-xL proteins were downregulated by blocking CDH17 gene in gastric cancer BGC823 cells after treatment with cisplatin. Moreover, down-expression of CDH17 enhanced the efficacy of cisplatin-induced inhibition of tumor growth in nude mice via apoptosis induction. Down-expression of CDH17 gene can significantly improve apoptosis-inducing effects of cisplatin in vitro and in vivo, which is a new strategy to improve chemotherapeutic effects on gastric cancer.

G-CSF ameliorates neuronal apoptosis through GSK-3β inhibition in neonatal hypoxia-ischemia in rats

Granulocyte-colony stimulating factor (G-CSF), a growth factor, has known neuroprotective effects in a variety of experimental brain injury models. Herein we show that G-CSF administration attenuates neuronal apoptosis after neonatal hypoxia-ischemia (HI) via glycogen synthase kinase-3β (GSK-3β) inhibition. Ten day old Sprague-Dawley rat pups (n=157) were subjected to unilateral carotid artery ligation followed by 2.5h of hypoxia or sham surgery. HI animals received control siRNA, GSK-3β siRNA (4 μL/pup), G-CSF (50 μg/kg), G-CSF combined with 0.1 or 0.4 nM G-CSF receptor (G-CSFR) siRNA, phosphatidylinositol 3-kinase (PI3K) inhibitor Wortmannin (86 ng/pup), or DMSO (vehicle for Wortmannin). Pups were euthanized 48 h post-HI to quantify brain infarct volume. G-CSFR, activated Akt (p-Akt), activated GSK-3β (p-GSK-3β), Cleaved Caspase-3 (CC3), Bcl-2, and Bax were quantified using Western blot analysis and the localizations of each was visualized via immunofluorescence staining. Neuronal cell death was determined using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Our results showed p-GSK-3β increased after HI until its peak at 48 h post-ictus, and both GSK-3β siRNA and G-CSF administration reduced p-GSK-3β expression, as well as infarct volume. p-GSK-3β and CC3 were generally co-localized in neurons. Furthermore, G-CSF increased p-Akt expression and the Bcl-2/Bax ratio and also decreased p-GSK-3β and CC3 expression levels in the ipsilateral hemisphere, which were all reversed by G-CSFR siRNA, Wortmannin, and GSK-3β siRNA. In conclusion, G-CSF attenuated caspase activation and reduced brain injury by inhibiting GSK-3β activity after experimental HI in rat pups. This neuroprotective effect was abolished by both G-CSFR siRNA and Wortmannin.

Synergistic effect of puerarin and 5-fluorouracil on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of human malignancy worldwide, which is becoming increasingly resistant to traditional drug treatments. Puerarin combined with 5-fluorouracil (5-FU) may be a useful treatment for liver cancer. The primary aim of the present study was to determine whether combined treatment with 5-FU and puerarin is more effective against the hepatocellular carcinoma (HCC) cell line, SMMC7721, than treatment with 5-FU or puerarin alone. The growth inhibition of SMMC7721 cells by puerarin or 5-FU alone or in combination was determined by the Cell Counting Kit-8 assay, in vitro. Apoptotic morphological features and the percentage of apoptotic cells were detected using Hoechst 33258 staining and an Annexin V/PI apoptosis kit, respectively. In addition, a tumor xenograft model was established in nude mice using SMMC7721 cells. Puerarin and 5-FU alone or in combination were injected into the mice, and the inhibition of tumor growth was evaluated by monitoring tumor volume and weight. Treatment with 6,400 or 640 μM 5-FU resulted in growth inhibition of 95.56±0.81 and 75.91±3.54%, respectively. The combination index values were <1 when the fraction of affected cells was between 0.2555 and 0.7420. Furthermore, the percentage of apoptotic cells was markedly increased in the combined treatment group when compared with that of the individual treatment groups, in vitro and in vivo. Individual treatment with puerarin resulted in a tumor volume inhibition rate (IR) of 70.58% and a tumor weight IR of 46.20%. Treatment with 5-FU was found to decrease the tumor volume by 76.26% and tumor weight by 49.86%. In the combined treatment group, the tumor volume and weight IRs were 93.11 and 75.21%, respectively. A marked increase in the inhibition of tumor growth and the number of apoptotic cells in response to combined treatment with puerarin and 5-FU was identified with no observed liver or renal toxicity. These results suggest that puerarin and 5-FU exhibit a synergistic treatment effect on the HCC SMMC7721 cell line.

Anti-neutrophil antibody enhances the neuroprotective effects of G-CSF by decreasing number of neutrophils in hypoxic ischemic neonatal rat model

OBJECTIVES

Neonatal hypoxia ischemia (HI) is an injury that can lead to neurological impairments such as behavioral and learning disabilities. Granulocyte-colony stimulating factor (G-CSF) has been demonstrated to be neuroprotective in ischemic stroke however it has also been shown to induce neutrophilia, ultimately exacerbating neuronal injury. Our hypothesis is that coadministration of anti-neutrophil antibody (Ab) with G-CSF will decrease blood neutrophil counts thereby reducing infarct volume and improving neurological function post HI brain injury.

METHODS

Rat pups were subjected to unilateral carotid artery ligation followed by 2.5h of hypoxia. Animals were randomly assigned to five groups: Sham (n=15), vehicle (HI, n=15), HI with G-CSF treatment (n=15), HI with G-CSF+Ab treatment (n=15), and HI with Ab treatment (n=15). Ab (325μg/kg) was administered intraperitoneally while G-CSF (50μg/kg) was administered subcutaneously 1h post HI followed by daily injections for 3 consecutive days. Animals were euthanized at 96h post HI for blood neutrophil counts and brain infarct volume measurements as well as at 5weeks for neurological function testing and brain weight measurements. Lung and spleen weights at both time points were further analyzed.

RESULTS

The G-CSF treatment group showed tendencies to reduce infarct volume and improve neurological function while significantly increasing neutrophil counts. On the other hand, the G-CSF+Ab group significantly reduced infarct volume, improved neurological function and decreased neutrophil counts. The Ab alone group showed reversal of the neuroprotective effects of the G-CSF+Ab group. No significant differences were found in peripheral organ weights between groups.

CONCLUSION

Our data suggest that coadministration of G-CSF with Ab not only prevented brain atrophy but also significantly improved neurological function by decreasing blood neutrophil counts. Hence the neuroprotective effects of G-CSF may be further enhanced if neutrophilia is avoided.

Delayed remote ischemic postconditioning improves long term sensory motor deficits in a neonatal hypoxic ischemic rat model

Objective

Remote Ischemic Postconditioning (RIPC) is a promising therapeutic intervention wherein a sub-lethal ischemic insult induced in one organ (limb) improves ischemia in an organ distant to it (brain). The main objective of this study was to investigate the long-term functional effects of delayed RIPC in a neonatal hypoxia-ischemia (HI) rat model.

Method

10 day old rat pups were subjected to delayed RIPC treatment and randomized into four groups: 1) Sham, 2) HI induced, 3) HI +24 hr delayed RIPC, and 4) HI +24 hr delayed RIPC with three consecutive daily treatments. Neurobehavioral tests, brain weights, gross and microscopic brain tissue morphologies, and systemic organ weights were evaluated at five weeks post surgery.

Results

HI induced rats performed significantly worse than sham but both groups of delayed RIPC treatment showed improvement of sensory motor functions. Furthermore, compared to the HI induced group, the delayed RIPC treatment groups showed no further detrimental changes on brain tissue, both grossly and morphologically, and no changes on the systemic organ weights.

Conclusion

Delayed RIPC significantly improves long term sensory motor deficits in a neonatal HI rat model. A 24 hr delayed treatment does not significantly attenuate morphological brain injury but does attenuate sensory motor deficits. Sensory motor deficits improve with both a single treatment and with three consecutive daily treatments, and the consecutive treatments are possibly being more beneficial.

Systemic G-CSF attenuates cerebral inflammation and hypomyelination but does not reduce seizure burden in preterm sheep exposed to global hypoxia-ischemia

Hypoxic-ischemic encephalopathy (HIE) is common in preterm infants, but currently no curative therapy is available. Cell-based therapy has a great potential in the treatment of hypoxic-ischemic preterm brain injury. Granulocyte-colony stimulating factor (G-CSF) is known to mobilize endogenous hematopoietic stem cells (HSC) and promotes proliferation of endogenous neural stem cells. On these grounds, we hypothesized that systemic G-CSF would be neuroprotective in a large translational animal model of hypoxic-ischemic injury in the preterm brain. Global hypoxia-ischemia (HI) was induced by transient umbilical cord occlusion in instrumented preterm sheep. G-CSF treatment (100μg/kg intravenously, during five consecutive days) was started one day before the global HI insult to ascertain mobilization of endogenous stem cells within the acute phase after global HI. Mobilization of HSC and neutrophils was studied by flow cytometry. Brain sections were stained for microglia (IBA-1), myelin basic protein (MBP) and myeloperoxidase (MPO) to study microglial proliferation, white matter injury and neutrophil invasion respectively. Electrographic seizure activity was analyzed using amplitude-integrated electroencephalogram (aEEG). G-CSF effectively mobilized CD34-positive HSC in the preterm sheep. In addition, G-CSF caused marked mobilization of neutrophils, but did not influence enhanced invasion of neutrophils into the preterm brain after global HI. Microglial proliferation and hypomyelination following global HI were reduced as a result of G-CSF treatment. G-CSF did not cause a reduction of the electrographic seizure activity after global HI. In conclusion, G-CSF induced mobilization of endogenous stem cells which was associated with modulation of the cerebral inflammatory response and reduced white matter injury in an ovine model of preterm brain injury after global HI. G-CSF treatment did not improve neuronal function as shown by seizure analysis. Our study shows that G-CSF treatment has neuroprotective potential following hypoxic-ischemic injury in the preterm brain.

Quantitative in vivo detection of brain cell death after hypoxia ischemia using the lipid peak at 1.3 ppm of proton magnetic resonance spectroscopy in neonatal rats

This study was performed to determine the accuracy of proton magnetic spectroscopy ((1)H-MRS) lipid peak as a noninvasive tool for quantitative in vivo detection of brain cell death. Seven day-old Sprague Dawley rats were subjected to 8% oxygen following a unilateral carotid artery ligation. For treatment, cycloheximide was given immediately after hypoxic ischemia (HI). Lipid peak was measured using (1)H-MRS at 24 hr after HI, and then brains were harvested for fluorocytometric analyses with annexin V/propidium iodide (PI) and fluorescent probe JC-1, and for adenosine-5'-triphosphate (ATP) and lactate. Increased lipid peak at 1.3 ppm measured with (1)H-MRS, apoptotic and necrotic cells, and loss of mitochondrial membrane potential (ΔΨ) at 24 hr after HI were significantly improved with cycloheximide treatment. Significantly reduced brain ATP and increased lactate levels observed at 24 hr after HI showed a tendency to improve without statistical significance with cycloheximide treatment. Lipid peak at 1.3 ppm showed significant positive correlation with both apoptotic and necrotic cells and loss of ΔΨ, and negative correlation with normal live cells. Lipid peak at 1.3 ppm measured by (1)H-MRS might be a sensitive and reliable diagnostic tool for quantitative in vivo detection of brain cell death after HI.

Granulocyte-colony stimulating factor in combination with stem cell factor confers greater neuroprotection after hypoxic-ischemic brain damage in the neonatal rats than a solitary treatment

Neonatal hypoxia-ischemia (HI) is a devastating condition resulting in neuronal cell death and often culminates in neurological deficits. Granulocyte-colony stimulating factor (G-CSF) has been shown to have neuroprotective activity via inhibition of apoptosis and inflammation in various stroke models. Stem cell factor (SCF) regulates hematopoietic stem cells in the bone marrow and has been reported to have neuroprotective properties in an experimental ischemic stroke model. In this study we aim to determine the protective effects of G-CSF in combination with SCF treatment after experimental HI. Seven-day old Sprague-Dawley rats were subjected to unilateral carotid artery ligation followed by 2.5 hours of hypoxia. Animals were randomly assigned to five groups: Sham (n=8), Vehicle (n=8), HI with G-CSF treatment (n=9), HI with SCF treatment (n=9) and HI with G-CSF+SCF treatment (coadministration group; n=10). G-CSF (50 µg/kg), SCF (50 µg/kg) and G-CSF+SCF (50 µg/kg) were administered intraperitoneally 1 hour post HI followed by daily injection for 4 consecutive days (five total injections). Animals were euthanized 14 days after HI for neurological testing. Additionally assessment of brain, heart, liver, spleen and kidney atrophy was performed. Both G-CSF and G-CSF+SCF treatments improved body growth and decreased brain atrophy at 14 days post HI. No significant differences were found in the peripheral organ weights between groups. Finally, the G-CSF+SCF coadministration group showed significant improvement in neurological function. Our data suggest that administration of G-CSF in combination with SCF not only prevented brain atrophy but also significantly improved neurological function.

The role of granulocyte colony-stimulating factor in the neutrophilia observed in the fetal inflammatory response syndrome

OBJECTIVES

Fetal neutrophilia is present in two-thirds of cases with the fetal inflammatory response syndrome (FIRS). The mechanisms responsible for this finding have not been elucidated. Granulocyte colony-stimulating factor (G-CSF) is the primary physiologic regulator of neutrophil production and plays a key role in the rapid generation and release of neutrophils in stressful conditions (i.e., infection). The objective of this study was to determine: 1) whether FIRS was associated with changes in fetal plasma G-CSF concentrations; and 2) if fetal plasma G-CSF concentrations correlated with fetal neutrophil counts, chorioamnionitis, neonatal morbidity/mortality and cordocentesis-to-delivery interval.

STUDY DESIGN

Percutaneous umbilical cord blood sampling was performed in a population of patients with preterm labor (n=107). A fetal plasma interleukin-6 (IL-6) concentration >11 pg/mL was used to define FIRS. Cord blood G-CSF was measured by a sensitive and specific immunoassay. An absolute neutrophil count was determined and corrected for gestational age. Receiver operating characteristic (ROC) curve, survival analysis and Cox proportional hazard model were employed.

RESULTS

1) G-CSF was detected in all fetal blood samples; 2) fetuses with FIRS had a higher median fetal plasma G-CSF concentration than those without FIRS (P<0.001); 3) a fetal plasma G-CSF concentration ≥134 pg/mL (derived from an ROC curve) was associated with a shorter cordocentesis-to-delivery interval, a higher frequency of chorioamnionitis (clinical and histological), intra-amniotic infection, and composite neonatal morbidity/mortality than a fetal plasma concentration below this cut-off; and 4) a fetal plasma G-CSF concentration ≥134 pg/mL was associated with a shorter cordocentesis-to-delivery interval (hazard ratio 3.2; 95% confidence interval 1.8-5.8) after adjusting for confounders.

CONCLUSIONS

1) G-CSF concentrations are higher in the peripheral blood of fetuses with FIRS than in fetuses without FIRS; and 2) a subset of fetuses with FIRS with elevated fetal plasma G-CSF concentrations are associated with neutrophilia, a shorter procedure-to-delivery interval, chorio-amnionitis and increased perinatal morbidity and mortality.

Flt3 ligand synergizes with granulocyte-colony-stimulating factor in bone marrow mobilization to improve functional outcome after spinal cord injury in the rat

BACKGROUND AIMS

The effect of granulocyte-colony-stimulating factor (G-CSF) and/or the cytokine fms-like thyrosin kinase 3 (Flt3) ligand on functional outcome and tissue regeneration was studied in a rat model of spinal cord injury (SCI).

METHODS

Rats with a balloon-induced compression lesion were injected with G-CSF and/or Flt3 ligand to mobilize bone marrow cells. Behavioral tests (Basso-Beattie-Bresnahan and plantar test), blood counts, morphometric evaluation of the white and gray matter, and histology were performed 5 weeks after SCI.

RESULTS

The mobilization of bone marrow cells by G-CSF, Flt3 ligand and their combination improved the motor and sensory performance of rats with SCI, reduced glial scarring, increased axonal sprouting and spared white and gray matter in the lesion. The best results were obtained with a combination of G-CSF and Flt3. G-CSF alone or in combination with Flt3 ligand significantly increased the number of white blood cells, but not red blood cells or hemoglobin content, during and after the time-course of bone marrow stimulation. The combination of factors led to infiltration of the lesion by CD11b(+) cells.

CONCLUSIONS

The observed improvement in behavioral and morphologic parameters and tissue regeneration in animals with SCI treated with a combination of both factors could be associated with a prolonged time-course of mobilization of bone marrow cells. The intravenous administration of G-CSF and/or Flt3 ligand represents a safe and effective treatment modality for SCI.

The evolving landscape of neuroinflammation after neonatal hypoxia-ischemia

Hypoxic-ischemic brain injury remains a leading cause of mortality and morbidity in neonates. The inflammatory response, which is characterized in part by activation of local immune cells, has been implicated as a core component for the progression of damage to the immature brain following hypoxia-ischemia (HI). However, mounting evidence implicates circulating immune cells recruited to the site of damage as orchestrators of neuron-glial interactions and perpetuators of secondary brain injury. This suggests that re-directing our attention from the local inflammatory response toward the molecular mediators believed to link brain-immune cell interactions may be a more effective approach to mitigating the inflammatory sequelae of perinatal HI. In this review, we focus our attention on cyclooxygenase-2, a mediator by which peripheral immune cells may modulate signaling pathways in the brain that lead to a worsened outcome. Additionally, we present an overview of emerging therapeutic modalities that target mechanisms of neuroinflammation in the hypoxic-ischemic neonate.

Granulocyte colony stimulating factor attenuates hyperoxia-induced lung injury by down-modulating inflammatory responses in neonatal rats

PURPOSE

Granulocyte colony stimulating factor (G-CSF) has been known to increase neutrophil production and have anti-inflammatory properties, but the effect of G-CSF on pulmonary system is in controversy. We investigated whether G-CSF treatment could attenuate hyperoxia-induced lung injury, and whether this protective effect is mediated by the down-modulation of inflammatory responses in a neonatal rat model.

MATERIALS AND METHODS

Newborn Sprague-Dawley rats (Orient Co., Seoul, Korea) were subjected to 14 days of hyperoxia (90% oxygen) beginning within 10 h after birth. G-CSF (20 μg/kg) was administered intraperitoneally on the fourth, fifth, and sixth postnatal days.

RESULTS

This treatment significantly improved hyperoxia-induced reduction in body weight gain and lung pathology such as increased mean linear intercept, mean alveolar volume, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling positive cells. Hyperoxia- induced activation of nicotinamide adenine dinucleotide phosphate oxidase, which is responsible for superoxide anion production, as evidenced by upregulation and membrane translocation of p67(phox) was significantly attenuated after G-CSF treatment, as were inflammatory responses such as increased myeloperoxidase activity and mRNA expression of transforming growth factor-β. However, the attenuation of other proinflammatory cytokines such as tumor necrosis factor-α and interleukin- 6 was not significant.

CONCLUSION

In sum, G-CSF treatment significantly attenuated hyperoxia-induced lung injury by down-modulating the inflammatory responses in neonatal rats.

Systemic G-CSF treatment does not improve long-term outcomes after neonatal hypoxic-ischaemic brain injury

Hypoxia-ischaemia (HI) is a major factor in the pathogenesis of developmental brain injury, leading to cognitive deficits and motor disabilities in preterm infants. The haematopoietic growth factor granulocyte colony-stimulating factor (G-CSF) has been shown to exert a neuroprotective activity in rodent models of ischaemic stroke and is currently subject to phase I/II clinical trials in adults. Results of studies examining the effect of G-CSF in perinatal brain damage have been contradictory. We have previously shown that G-CSF increases NMDAR-mediated excitotoxic brain injury in the neonatal mouse brain. In this study, we evaluated the effect of G-CSF on long-term outcomes after HI. On postnatal day 5, mice pubs were first randomly assigned to a sham operation or HI and then divided into four treatment groups: i) G-CSF; ii) phosphate buffered saline (PBS) 1h after injury; iii) G-CSF and iv) PBS 60 h after injury. G-CSF (200 μg/kg BW) was administered five times within a 24h interval. Neuromotor and cognitive outcomes were assessed by open-field, novel object recognition tests and rotarod tests starting on P90, with subsequent histological analyses of brain injury. G-CSF treatment did not improve either neurobehavioural outcomes or brain injuries. Interestingly, the application of PBS and G-CSF in the acute phase increased brain damage in the hippocampus. We could not confirm the neuroprotective properties of G-CSF in neonatal HI brain damage. The exacerbation of injury by the administration of substances in the acute phase might indicate a heightened state of neurological sensitivity that is specific to mechanisms of secondary neurodegeneration and influenced by unidentified external factors possibly associated with the treatment protocol during the acute phase. This article is part of a Special Issue entitled "Interaction between repair, disease, & inflammation."

Comparative evaluation of hypoxic-ischemic brain injury by flow cytometric analysis of mitochondrial membrane potential with JC-1 in neonatal rats

We assessed the validity of monitoring changes in mitochondrial membrane potential (ΔΨ) with a fluorescent probe, JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl benzimidazolo-carbocyanine iodide), for the quantitative evaluation of neonatal hypoxic-ischemic brain injury. Seven-day-old rat pups were subjected to 2h of 8% oxygen following unilateral carotid artery ligation. Brain tissue was obtained for JC-1 staining at 24h after hypoxia ischemia (HI), and the results were compared with those of other simultaneous measurements such as flow cytometry with fluoresceinated annexin V/propidium iodide (PI), terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) staining, triphenyl tetrazolium chloride (TTC) infarct area and western blot for cytosolic cytochrome c. Flow cytograms of JC-1 showed two distinct sub-populations with different ΔΨ, red with high ΔΨ and green with low ΔΨ, at 24h after HI. This shift of JC-1 fluorescence from red to green indicated a collapse of ΔΨ. The increased percentage of low ΔΨ with JC-1 showed a significant positive correlation with a simultaneous increase in annexin V(+)/PI(+) necrotic cells, TUNEL-positive cells, TTC infarct area and western blot of cytosolic cytochrome c, and negative correlation with annexin V(-)/PI(-) live cells. In summary, low ΔΨ measured with JC-1 was significantly correlated with results from other methods used to assess the extent of brain damage after HI. Therefore, fluorocytometric analysis of ΔΨ with JC-1 might be a sensitive and reliable technique in the quantitative evaluation of neonatal brain injury.

Noscapine induces mitochondria-mediated apoptosis in gastric cancer cells in vitro and in vivo

PURPOSE

Noscapine plays an important role in the regulation of cell growth and death. It has been reported to potentiate the anti-tumor effect by inducing apoptosis in various malignant cells. However, the mechanism of inducing apoptosis in gastric cancer cells by this agent remains to be clarified.

METHODS

In the study, we investigated the signaling pathways by which noscapine induces apoptosis in gastric cancer cell lines. Apoptosis of four human gastric cancer cell lines was induced by treatment with noscapine.

RESULTS

Our results indicate that noscapine induced a dose-dependent apoptosis of these cells. The treatment with noscapine upregulated Bax and Cytochrome c (Cyt-c) protein, downregulated Bcl-2 protein. Caspase-3 and caspase-9 were activated, suggesting that the apoptosis is mediated by mitochondrial pathways. Moreover, in xenograft tumor mouse model, noscapine injection successfully inhibited the tumor growth via apoptosis induction which was demonstrated by TUNEL assay.

CONCLUSIONS

These data of the study suggest that noscapine induces apoptosis in gastric cancer cells via mitochondrial pathways.

Long-term evaluation of granulocyte-colony stimulating factor on hypoxic-ischemic brain damage in infant rats

PURPOSE

Hypoxia-ischemia (HI), as a major cause of fetal brain damage, has long-lasting neurological implications. Therefore, therapeutic interventions that attenuate the neuropathological outcome of HI while also improving the neurofunctional outcome are of paramount clinical importance. The aim of this study was to investigate the long-term functional and protective actions of granulocyte-colony stimulating factor (G-CSF) treatment in an experimental model of cerebral HI.

METHODS

Postnatal day-7 Sprague-Dawley rats were subjected to HI surgery, which entailed ligation of the right common carotid artery followed by 2 h of hypoxia (8% O(2)). Treatment consisted of subcutaneous injection of G-CSF at 1 h after hypoxia followed by an additional one injection per day for 5 days (6 total injections) or for 10 days (11 total injections). Animals were euthanized 5 weeks post-insult for extensive evaluation of neurological deficits and assessment of brain, spleen, heart, and liver damage.

RESULTS

G-CSF treatment promoted somatic growth and prevented brain atrophy and underdevelopment of the heart. Moreover, reflexes, limb placing, muscle strength, motor coordination, short-term memory, and exploratory behavior were all significantly improved by both G-CSF dosing regimens.

CONCLUSIONS

Long-term neuroprotection afforded by G-CSF in both morphological and functional parameters after a hypoxic-ischemic event in the neonate provides a rationale for exploring clinical translation.

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.

Triptolide exerts anti-tumor effect on oral cancer and KB cells in vitro and in vivo

Triptolide (TPL), a diterpenoid triepoxide purified from the Chinese herb Tripterygium wilfordii Hook F, has been reported to potentiate the anti-tumor effect in various cancer cells. However, the effect of TPL on oral cancers is not yet evaluated. Herein we first demonstrate that TPL induces prominent growth inhibition and apoptosis in two oral cancer cell lines, SCC25 and OEC-M1 and in KB cells. Our results indicate that TPL induces a dose-dependent apoptosis of these cells at nanomolar concentration. Apoptosis signalings are both activated through time upon TPL treatment detected by elevated caspase-3, 8, 9 activities. In xenograft tumor mouse model, TPL injection successfully inhibits the tumor growth via apoptosis induction which was demonstrated by TUNEL assay. These results demonstrate that TPL exerts anti-tumor effect on oral cancer and KB cells and suggest further the potential of TPL combining with other chemotherapeutic agents or radiotherapy for advanced oral cancer.