Brain Activation Evoked by Sensory Stimulation in Patients with Spinal Cord Injury : Functional Magnetic Resonance Imaging Correlations with Clinical Features.

OBJECTIVE: The purpose of this study is to determine whether the changes of contralateral sensorimotor cortical activation on functional magnetic resonance imaging (fMRI) can predict the neurological outcome among spinal cord injury (SCI) patients when the great toes are stimulated without notice. METHODS: This study enrolled a total of 49 patients with SCI and investigated each patient's preoperative fMRI, postoperative fMRI, American Spinal Injury Association (ASIA) score, and neuropathic pain occurrence. Patients were classified into 3 groups according to the change of blood oxygenation level dependent (BOLD) response on perioperative fMRI during proprioceptive stimulation with repetitive passive toe movements : 1) patients with a response of contralateral sensorimotor cortical activation in fMRI were categorized; 2) patients with a response in other regions; and 3) patients with no response. Correlation between the result of fMRI and each parameter was analyzed. RESULTS: In fMRI data, ASIA score was likely to show greater improvement in patients in group A compared to those belonging to group B or C (p<0.001). No statistical significance was observed between the result of fMRI and neuropathic pain (p=0.709). However, increase in neuropathic pain in response to the signal change of the ipsilateral frontal lobe on fMRI was statistically significant (p=0.030). CONCLUSION: When there was change of BOLD response at the contralateral sensorimotor cortex on perioperative fMRI after surgery, relief of neurological symptoms was highly likely for traumatic SCI patients. In addition, development of neuropathic pain was likely to occur when there was change of BOLD response at ipsilateral frontal lobe.

Grisel's Syndrome Induced by Mycobacterium tuberculosis.

Grisel's syndrome is a non-traumatic subluxation of the atlantoaxial joints, which is caused by an inflammatory process in the upper neck. It is rare to find literary reports of Grisel's syndrome with an evident pathogen in a lesion. For the first time in Korea, we report a 36-year-old female with Grisel's syndrome having an atlantoaxial subluxation, which was caused by a retropharyngeal abscess secondary to pulmonary Mycobacterium tuberculosis. The patient was treated with an anti-tuberculosis regimen and was prescribed a Philadelphia collar for the control of torticollis. The result of magnetic resonance imaging (MRI) showed an improved atlantoaxial alignment, after drug treatment and immobilization. This patient was neurologically intact and free from symptomatic complaints at follow-up visit. Dynamic cervical radiograph confirmed that the atlantoaxial joints had been stable. The pathophysiology of Grisel's syndrome, along with anatomical attributes, was explained on the basis of the patient's clinical course.

Improvement in sensory function via granulocyte-macrophage colony-stimulating factor in rat spinal cord injury models.

OBJECT: The aim in this study was to determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF) leads to sensory improvement in rat spinal cord injury (SCI) models. METHODS: Thirty male Sprague-Dawley rats were included in this study: 10 in the sham group (laminectomy alone without SCI), 10 in the SCI group (SCI treated with phosphate-buffered saline), and 10 in the GM-CSF treatment group (SCI treated with GM-CSF). A locomotor function test and pain sensitivity test were conducted weekly for 9 weeks after SCI or sham injury. Spinal tissue samples from all rats were immunohistochemically examined for the expression of calcitonin gene-related peptide (CGRP) and abnormal sprouting at Week 9 post-SCI. RESULTS: Granulocyte-macrophage colony-stimulating factor treatment improves functional recovery after SCI. In the tactile withdrawal threshold and frequency of the hindlimb paw, the GM-CSF group always responded with a statistically significant lower threshold than the SCI group 9 weeks after SCI (p < 0.05). The response of the forelimb and hindlimb paws to cold in the GM-CSF group always reflected a statistically significant lower threshold than in the SCI group 9 weeks after injury (p < 0.05). Decreased CGRP expression, observed by density and distribution area, was noted in the GM-CSF group (optical density 113.5 ± 20.4) compared with the SCI group (optical density 143.1 ± 18.7; p < 0.05). CONCLUSIONS: Treatment with GM-CSF results in functional recovery, improving tactile and cold sense recovery in a rat SCI model. Granulocyte-macrophage colony-stimulating factor also minimizes abnormal sprouting of sensory nerves after SCI.

Interobserver and Intraobserver Reliability of Sub-Axial Injury Classification and Severity Scale between Radiologist, Resident and Spine Surgeon.

OBJECTIVE: The sub-axial injury classification (SLIC) and severity scale was developed to decide whether to operate the cervical injured patient or not, but the reliability of SLIC and severity scale among the different physicians was not well known. Therefore, we evaluated the reliability of SLIC among a spine surgeon, a resident of neurosurgery and a neuro-radiologist. METHODS: In retrograde review in single hospital from 2002 to 2009 years, 75 cases of sub-axial spine injured patients underwent operation. Each case was blindly reviewed for the SLIC and severity scale by 3 different observers by two times with 4 weeks interval with randomly allocated. The compared axis was the injury morphology score, the disco-ligamentous complex score, the neurological status score and total SLIC score; the neurological status score was derived from the review of medical record. The kappa value was used for the statistical analysis. RESULTS: Interobserver agreement of SLIC and severity scale was substantial agreement in the score of injury morphology [intraclass correlation (ICC)=0.603] and total SLIC and severity sacle (ICC value=0.775), but was fair agreement in the disco-ligamentous complex score (ICC value=0.304). Intraobserver agreements were almost perfect agreement in whole scales with ICC of 0.974 in a spine surgeon, 0.948 in a resident of neurosurgery, and 0.963 in a neuro-radiologist. CONCLUSION: The SLIC and severity scale is comprehensive and easily applicable tool in spine injured patient. Moreover, it is very useful tool to communicate among spine surgeons, residents of neurosurgery and neuro-radiologists with sufficient reproducibility.

Radiological Efficacy of Cervical Lateral Mass Screw Insertion and Rod Fixation by Modified Magerl's Method (Yoon's Method) with Minimum 2 Years of Follow-up.

OBJECTIVE: Cervical lateral mass screw insertion and rod fixation is a useful method for stabilizing the cervical disease, so various modified techniques were present. Many surgeons had reported the biomechanical safety according to the screw positioning method in the cervical spine, but the modified Magerl's method (Yoon's method) was not well studied. So, this study assessed the radiological efficacy of the modified Magerl's method with long-term follow-up. METHODS: This study retrospectively reviewed 323 lateral mass screws of 50 patients who had followed-up at least 2 years. Radiologic data were analyzed as parameters of complications after operation, including kyphotic or lordotic change, bone fusion, pull-out or malposition of screw, foraminal stenosis, adjacent disc degeneration or aggravation, pseudoarthrosis, and vertebral artery injury. RESULTS: The mean follow-up period was 32 (24 to 52) months. There were kyphotic changes in 4.0%(2 of 50 cases). Unsuccessful bone fusion occurred in 4.0%(2 of 50 cases). Among the 323 screws, screw pull-out (4.0%. 2 of 50cases, 3 of 323 screws), foraminal invasion (1.2% of total screws), and facet injury (0.6% of total screws) occurred. CONCLUSION: The lateral mass screw insertion and rod fixation by the modified Magerl's method (Yoon's method) is a safe and reliable technique with low rate of complication related to instruments in minimum 2 years follow-up.

Lumbar disc screening using back pain questionnaires: oswestry low back pain score, aberdeen low back pain scale, and acute low back pain screening questionnaire.

OBJECTIVE: To evaluate the usefulness of back pain questionnaires for lumbar disc screening among Korean young males. METHODS: We carried out a survey for lumbar disc screening through back pain questionnaires among the volunteers with or without back pain. Three types of back pain questionnaire (Oswestry Low Back Pain Score, Aberdeen Low Back Pain Scale, and Acute Low Back Pain Screeing Questionnaire) were randomly assigned to the examinees. The authors reviewed lumbar imaging studies (simple lumbar radiographs, lumbar computed tomography, and magnetic resolutional images), and the severity of lumbar disc herniation was categorized according to the guidelines issued by the Korean military directorate. We calculated the relationship between the back pain questionnaire scores and the severity of lumbar disc herniation. RESULTS: The scores of back pain questionnaires increased according to the severity of lumbar disc herniation. But, the range of scores was very vague, so it is less predictable to detect lumbar disc herniation using only back pain questionnaires. The sensitivity between the back pain questionnaires and the presence of lumbar disc herniation was low (16-64%). CONCLUSION: Screening of lumbar disc herniation using only back pain questionnaires has limited value.

Prevalence of Lumbar Disc Herniation in Adolescent Males in Seoul, Korea: Prevalence of Adolescent LDH in Seoul, Korea.

OBJECTIVE: The authors surveyed the prevalence and the clinical character of lumbar disc herniation (LDH) in Korean male adolescents, and the usefulness of current conscription criteria. METHODS: The data of 39,673 nineteen-year-old males that underwent a conscription examination at the Seoul Regional Korean Military Manpower Administration (MMA) from October 2010 to May 2011 were investigated. For those diagnosed as having lumbar disc herniation, prevalences, subject characteristics, herniation severities, levels of herniation, and modified Korean Oswestry low back pain disability scores by MMA physical grade were evaluated. The analysis was performed using medical certificates, medical records, medical images, and electromyographic and radiologic findings. RESULTS: The prevalence of adolescent LDH was 0.60%(237 of the 39,673 study subjects), and the prevalence of serious adolescent LDH with thecal sac compression or significant discogenic spinal stenosis was 0.28%(110 of the 39,673 study subjects). Of the 237 adolescent LDH cases, 105 (44.3%) were of single level LDH and 132 (55.7%) were of multiple level LDH, and the L4-5 level was the most severely and frequently affected. Oswestry back pain disability scores increased with herniation severity (p<0.01), and were well correlated with MMA grade. CONCLUSIONS: In this large cohort of 19-year-old Korean males, the prevalence of adolescent LDH was 0.60% and the prevalence of serious adolescent LDH, which requires management, was relatively high at 0.28%. MMA physical grade was confirmed to be a useful measure of the disability caused by LDH.

Metronidazole induced encephalopathy in a patient with brain abscess.

Metronidazole is commonly used for brain abscess but is not well known for its neurotoxic complications. Metronidazole-induced encephalopathy (MIEP) is toxic encephalopathy associated with the use of metronidazole. We experienced a case of brain abscess which developed reversible severe MIEP during treatment period. Although MIEP occurs in typical locations, it is not easy to differentiate from other conditions such as cerebral infarction, demyelinating diseases and metabolic diseases. Neurosurgeons should be aware that severe MIEP can occur during the use of metronidazole though it is not common.

Reduction in programmed cell death and improvement in functional outcome of transient focal cerebral ischemia after administration of granulocyte-macrophage colony-stimulating factor in rats. Laboratory investigation.

OBJECT: Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a potent hematopoietic growth factor that both enhances the survival and drives the differentiation and proliferation of myeloid lineage cells. Recent studies have suggested that GM-CSF has a neuroprotective effect against CNS injury. In this paper, the authors investigated the neuroprotective effect of GM-CSF on neuron survival and locomotor behavior in a rat model of focal cerebral ischemic injury. MATERIALS: To understand its neuroprotective effect in vitro, GM-CSF was administered to a glutamate-induced excitotoxicity neuronal injury cell culture model that mimics the pathophysiology of focal hypoxic cerebral injury. In the animal study, the authors prepared a rat focal cerebral ischemia model by occluding the unilateral middle cerebral artery. They then examined the effects of GM-CSF administration on changes in infarct volume, apoptosis-related gene expression, and improvement in locomotor behavior. RESULTS: Treatment with GM-CSF significantly increased cell viability in a cell culture model of glutamate-induced neuronal injury. Furthermore, in vivo administration of GM-CSF at 60 microg/kg body weight daily for 5 consecutive days beginning immediately after injury decreased infarction volume, altered the expression of several apoptosis-related genes (Bcl-2, Bax, caspase 3, and p53), and improved locomotor behavior in the focal cerebral ischemia model. CONCLUSIONS: The GM-CSF had neuroprotective effects in in vitro and in vivo experiments and resulted in decreased infarction volume and improved locomotor behavior. Although the specific mechanism involved in stroke recovery was not fully elucidated as it was not the primary focus of this study, administration of GM-CSF appeared to decrease the extent of neuronal apoptosis by modulating the expression of several apoptosis-related genes such as Bcl-2, Bax, caspase 3, and p53. Further investigations are necessary to better understand the role of GM-CSF on neural regeneration during the recovery phase of a stroke, as well as the intracellular signal transduction pathways that mediate neuroprotection.

GM-CSF inhibits glial scar formation and shows long-term protective effect after spinal cord injury.

OBJECT: This study investigated the effects of granulocyte macrophage-colony stimulating factor (GM-CSF) on the scar formation and repair of spinal cord tissues in rat spinal cord injury (SCI) model. METHODS: Sprague-Dawley male rats (8 weeks old) were randomly divided into the sham-operated group, spinal cord injury group, and injury with GM-CSF treated group. A spinal cord injury was induced at T9/10 levels of rat spinal cord using a vascular clip. GM-CSF was administrated via intraperitoneal (IP) injection or on the dural surface using Gelfoam at the time of SCI. The morphological changes, tissue integrity, and scar formation were evaluated until 4 weeks after SCI using histological and immunohistochemical analyses. RESULTS: The administration of GM-CSF either via IP injection or local treatment significantly reduced the cavity size and glial scar formation at 3-4 weeks after SCI. GM-CSF also reduced the expression of core proteins of chondroitin sulfate proteoglycans (CSPGs) such as neurocan and NG2 but not phosphacan. In particular, an intensive expression of glial fibriallary acidic protein (GFAP) and neurocan found around the cavity at 4 weeks was obviously suppressed by GM-CSF. Immunostaining for neurofilament (NF) and Luxol fast blue (LFB) showed that GM-CSF preserved well the axonal arrangement and myelin structure after SCI. The expression of GAP-43, a marker of regenerating axons, also apparently increased in the rostral grey matter by GM-CSF. CONCLUSION: These results suggest that GM-CSF could enhance long-term recovery from SCI by suppressing the glial scar formation and enhancing the integrity of axonal structure.

Gene therapy of neural cell injuries in vitro using the hypoxia-inducible GM-CSF expression plasmids and water-soluble lipopolymer (WSLP).

Non-viral polymeric gene carriers have been widely investigated but no promising biocompatible polymer was developed for the gene therapy of neural system injuries yet. This study evaluated the potential usage of water-soluble lipopolymer (WSLP) as a gene delivery vehicle in neural lineage cells of SK-N-BE(2)C, a neuroblastoma cell line and primary culture of mouse neural progenitor cells (mNPCs). When tested with the luciferase reporter (pSV-Luc), WSLP showed higher gene transfection efficiency by more than 8-10 folds yet with lower cytotoxicity than polyethylenimine of 1800 Da (PEI1800), a parental polymer, and Lipofectamine 2000. The optimum N/P ratios were 40:1 for WSLP and 10:1 for PEI1800, respectively. The transfection efficiency for both of WSLP and PEI1800 was higher overall in SK-N-BE(2)C cells than in mNPCs. WSLP was also used successfully for the delivery and hypoxia-inducible expression of luciferase reporter plasmid containing the erythropoietin (Epo) enhancer (pEpo-SV-Luc) or RTP801 promoter (pRTP801-Luc). The hypoxia-inducible system and WSLP were then successfully applied to the delivery of granulocyte macrophage colony-stimulating factor (GM-CSF) gene that was previously shown to have neuroprotective effect on neural cell death in vitro and in rat SCI model. The hypoxia-inducible GM-CSF plasmids (pEpo-SV-GM-CSF and pRTP801-GM-CSF) showed induced expression of GM-CSF under hypoxia and decrease in the hypoxia-induced cell death in SK-N-BE(2)C cells. In conclusion, this study demonstrated that WSLP could be an efficient gene delivery carrier for neural cells and gene therapy of GM-CSF using the hypoxia-inducible system could be a potential therapeutic intervention for neural injuries. Further studies are necessary to confirm the current findings in animal models of CNS injuries.

Comparative Study of Outcomes between Shunting after Cranioplasty and in Cranioplasty after Shunting in Large Concave Flaccid Cranial Defect with Hydrocephalus.

OBJECTIVE: The cranioplasty and ventriculoperitoneal (VP) shunt operation have been used to treat a large cranial defect with posttraumatic hydrocephalus (PTH). The aim of this study was to evlauate the difference of outcomes between in the shunting after the cranioplasty (group 1) and the cranioplasty after the shunting (group 2) in a large flaccid cranial defect with PTH. METHODS: In this study, a retrospective review was done on 23 patients undergoing the cranioplasty and VP shunt operation after the decompressive craniectomy for a refractory intracranial hypertension from 2002 to 2005. All of 23 cases had a large flaccid concave cranial defect and PTH. Ten cases belong to group 1 and 13 cases to group 2. The outcomes after operations were compared in two groups 6 months later. RESULTS: The improvement of Glasgow outcome scale (GOS) was seen in 8 cases (80.0%) of total 10 cases in group 1, and 6 cases (46.2%) of 13 cases in group 2. Three (75.0%) of 4 cases with hemiparesis in group 1 and 3 of 6 cases (50.0%) in group 2 were improved. All cases (2 cases) with decrease of visual acuity were improved in each group. Dysphasia was improved in 3 of 5 cases (60%) in group 1 and 4 of 6 cases (66.6%) in group 2. CONCLUSION: These results suggest that outcomes in group 1 may be better than in group 2 for a large flaccid concave cranial defect with PTH.

Time course of symptom disappearance after microvascular decompression for hemifacial spasm.

OBJECTIVE: This study is to investigate time course of symptom disappearance in patients whose spasm relieved completely after microvascular decompression (MVD). METHODS: Of 115 patients with hemifacial spasm (HFS) who underwent MVD from April 2003 to December 2006, 89 patients who had no facial paralysis after operation and showed no spasm at last follow-up more than 1.5 years after operation were selected. Symptom disappearance with time after MVD was classified into type 1 (symptom disappearance right after operation), type 2 (delayed symptom disappearance) and type 3 (unusual symptom disappearance). Type 2 was classified into type 2a (with postoperative silent period) and type 2b (without silent period). RESULTS: Type 1, type 2a, type 2b and type 3 were 38.2%, 48.37%, 12.4% and 1.1%, respectively. Delayed disappearance group (type 2) was 60.7%. Post-operative symptom duration in all cases ranged from 0 to 900 days, average was 74.6 days and median was 14 days. In case of type 2, average post-operative symptom duration was 115.1 days and median was 42 days. Five and 3 patients required more than 1 year and 2 years, respectively, until complete disappearance of spasm. In type 2a, postoperative silent period ranged from 1 to 10 days, with an average of 2.4 days. CONCLUSION: Surgeons should be aware that delayed symptom disappearance after MVD for HFS is more common than it has been reported, silent period can be as long as 10 days and time course of symptom disappearance is various as well as unpredictable.

Hypoxia-inducible expression of vascular endothelial growth factor for the treatment of spinal cord injury in a rat model.

OBJECT: Vascular endothelial growth factor (VEGF) has been investigated as a therapy for many disorders and injuries involving ischemia. In this report, we constructed and evaluated a hypoxia-inducible VEGF expression system as a treatment for spinal cord injury (SCI). METHODS: The hypoxia-inducible VEGF plasmid was constructed using the erythropoietin (Epo) enhancer with the Simian virus 40 (SV40) promoter (pEpo-SV-VEGF) or the RTP801 promoter (pRTP801-VEGF). The expression of VEGF in vitro was evaluated after transfection into N2A cells. The plasmids were then injected into rat spinal cords with contusion injuries. The expression of VEGF in vivo was measured using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Locomotor recovery in the rats was evaluated using the Basso, Beattie and Bresnahan (BBB) scale for locomotor analysis. RESULTS: In vitro transfection showed that pEpo-SV-VEGF or pRTP801-VEGF induced VEGF expression under hypoxic conditions, whereas pSV-VEGF did not. The VEGF level was higher in the pEpo-SV-VEGF and pRTP801-VEGF groups than in the control group. The VEGF expression was detected in neurons and astrocytes of the spinal cord. Locomotor recovery was improved in the pEpo-SV-VEGF and pRTP801-VEGF groups, and BBB scores were higher than in the control group. Staining using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling showed that the number of apoptotic cells decreased in the plasmid-injected groups compared with the control group, and significant differences were observed between the hypoxia-responsive groups and the pSV-VEGF group. CONCLUSIONS: These results suggest that the hypoxia-inducible VEGF expression system may be useful for gene therapy of SCI.

Signal transduction pathways of GM-CSF in neural cell lines.

GM-CSF is recently being suggested to play important role(s) in the nervous system. Present study was intended to understand signal transduction pathways of GM-CSF in human neuroblastoma (SK-N-(BE)2) and glioblastoma (A172) cell lines. The expression of GM-CSF receptors on the surface of these cells was confirmed by immunocytochemistry, Western blot analysis and RT-PCR. When treated for 10min, GM-CSF activated the signal transducer and activator of transcription 5 (STAT5) and extracellular signal regulated kinase (ERK) in both cell lines. However, Janus kinase 2 (JAK2) was activated only in A172 cells but not in SK-N-(BE)2 cells by GM-CSF. The GM-CSF-activated cellular signal pathways were specifically inhibited by the pretreatment of GM-CSF receptor alpha antibody, suggesting the specificity of the signal activation. The experiment using specific inhibitors (AG490) to the JAK/STAT pathway showed that JAK2/STAT5 cascade was well preserved and activated by GM-CSF in A172 cells, while STAT5 was activated by GM-CSF without JAK2 activation in SK-N-(EB)2 cells. The ERK pathway was activated by GM-CSF independently of JAK2 in both cell lines. Finally, GM-CSF showed cytoprotective effect on these cell lines by inhibiting cytotoxicity of saturosporine. The results revealed the signal transduction pathways activated by GM-CSF in neural cells and suggested that GM-CSF might affect the neural functions via these signal pathways.

What are the causative factors for a slow, progressive enlargement of a chronic subdural hematoma?

PURPOSE: To test the hypothesis that chronic subdural hematoma (CSDH) enlarges by the causative factors, this study has performed. MATERIALS AND METHODS: In 10 patients with CSDH, coagulation factors in venous blood taken at the time of surgery and hematomic contents aspirated from the CSDH were studied, using both laboratory assays and microscopy. RESULTS: When compared to the range of normal plasma, the hematoma fluids demonstrated a marked reduction in factor II, V, VII, VIII, and X, moderate reduction of factors IX and XI, and slight reduction of factor XII. Activated protein C and antithrombin III levels were decreased. The FDP (Fibrinogen Degradation Product) levels in chronic subdural hematoma were extremely high. The endothelial cells of the macrocapillaries (also called ''sinusoid'') showed numerous gap junctions between adjacent endothelial cells and a thinness or absence of the basement membrane, suggesting that the macrocapillaries are very fragile and susceptible to bleeding. CONCLUSION: Excessive coagulation in the hematoma, predominantly via the extrinsic clotting pathway, local hyperfibrinolysis, transmitted pulsations, and characteristics of the macrocapillaries play an important role in the leakage of blood and the enlargement of CSDH.

Complete spinal cord injury treatment using autologous bone marrow cell transplantation and bone marrow stimulation with granulocyte macrophage-colony stimulating factor: Phase I/II clinical trial.

To assess the safety and therapeutic efficacy of autologous human bone marrow cell (BMC) transplantation and the administration of granulocyte macrophage-colony stimulating factor (GM-CSF), a phase I/II open-label and nonrandomized study was conducted on 35 complete spinal cord injury patients. The BMCs were transplanted by injection into the surrounding area of the spinal cord injury site within 14 injury days (n = 17), between 14 days and 8 weeks (n = 6), and at more than 8 weeks (n = 12) after injury. In the control group, all patients (n = 13) were treated only with conventional decompression and fusion surgery without BMC transplantation. The patients underwent preoperative and follow-up neurological assessment using the American Spinal Injury Association Impairment Scale (AIS), electrophysiological monitoring, and magnetic resonance imaging (MRI). The mean follow-up period was 10.4 months after injury. At 4 months, the MRI analysis showed the enlargement of spinal cords and the small enhancement of the cell implantation sites, which were not any adverse lesions such as malignant transformation, hemorrhage, new cysts, or infections. Furthermore, the BMC transplantation and GM-CSF administration were not associated with any serious adverse clinical events increasing morbidities. The AIS grade increased in 30.4% of the acute and subacute treated patients (AIS A to B or C), whereas no significant improvement was observed in the chronic treatment group. Increasing neuropathic pain during the treatment and tumor formation at the site of transplantation are still remaining to be investigated. Long-term and large scale multicenter clinical study is required to determine its precise therapeutic effect. Disclosure of potential conflicts of interest is found at the end of this article.

GM-CSF inhibits apoptosis of neural cells via regulating the expression of apoptosis-related proteins.

Recently, we reported that GM-CSF showed therapeutic effects on the spinal cord injury (SCI) in rat model possibly via its anti-apoptotic activity in the nervous system. This study investigated the molecular mechanism of its anti-apoptotic and neuroprotective effects in N2a neuroblastoma cells and in rat SCI model. GM-CSF inhibited staurosporine-induced cytotoxicity and apoptosis of N2a cells. Single administration of GM-CSF either intraperitoneally or locally using a gelfoam, clearly reduced the apoptotic events in the surrounding region of the injury site in rat SCI model. Immunohistochemical analysis showed that apoptosis of cells occurred mainly in the neurons, but not significantly in the astrocytes in the surrounding regions. In both N2a cells and in rat SCI model, GM-CSF actually reduced the expression of pro-apoptotic proteins (p53, p21(WAF1/CIP1) and Bax), while further induced that of an anti-apoptotic protein (Bcl-2). In the Basso-Beattie-Bresnahan (BBB) locomotor test, the single GM-CSF administration showed better behavioral recovery than the untreated control only at early times within 1 week after injury. Overall, GM-CSF was shown to exert its neuroprotective effect on the neural injury by regulating the expression of apoptosis related genes, providing the molecular basis on its anti-apoptotic activity. Longer administration of GM-CSF appeared to be necessary for the sustained functional recovery from SCI.

A hypoxia-inducible gene expression system using erythropoietin 3' untranslated region for the gene therapy of rat spinal cord injury.

Many neurologic disorders are accompanied by ischemic injury during the pathologic process. To develop a controllable and injury-specific gene therapy system for the neurologic disorders, we constructed a hypoxia inducible plasmid with the erythropoietin (Epo) 3' untranslated region (UTR), which can enhance the stability of target mRNAs in response to hypoxia. The Epo 3' UTR was inserted at the 3' flanking region of luciferase gene in pSV-Luc, resulting in the construction of pSV-Luc-EpoUTR. In pEpo-SV-Luc-EpoUTR, the Epo enhancer was inserted into the upstream of the SV40 promoter to increase the hypoxia inducibility. The plasmids were evaluated in N2a mouse neuroblastoma cells under hypoxic conditions and in a rat spinal cord injury (SCI) model. The results showed that the Epo 3' UTR alone showed a three-fold increase in luciferase activity in hypoxic N2a cells as well as in the rat SCI model when compared to the sham control. In contrast, the Epo 3' UTR showed no effect on the luciferase activity in the presence of the Epo enhancer, probably because the Epo enhancer was more sensitive to hypoxia and showed a dominant effect. However, the Epo enhancer itself showed high level of luciferase activity even in normoxia (about five to eight-folds increase), while the Epo 3' UTR did not show enhanced background activity. Immunohistochemical staining showed expression of luciferase from pSV-Luc-EpoUTR both in neurons and astrocytes around the injured spinal cord of rat. These results suggest that the Epo 3' UTR could provide a specific and safe system for the hypoxia-inducible gene therapy of the neurologic disorders including SCI.