Methylprednisolone Inhibits Production of Interleukin-1?? and Interleukin-6 in the Spinal Cord Following Compression Injury in Rats

Melatonin and Methylprednisolone Combination Ameliorates Inflammation and Enhances Recovery After Sciatic Nerve Crush Injury

This sham-controlled animal study aimed to investigate the effects of melatonin and methylprednisolone combination on motor function, nerve conduction and histopathological and biochemical findings in rats with sciatic nerve crush injury. Forty-eight male Sprague-Dawley rats were divided into 6 groups (n = 8): CT: control, VEH: sciatic nerve injury, LMP: 15-mg/kg methylprednisolone, high-dose methylprednisolone (HMP): 30-mg/kg methylprednisolone, MEL: 15-mg/kg melatonin, MMP: 15-mg/kg methylprednisolone+15-mg/kg melatonin. The rats were evaluated with Sciatic Functional Index (SFI), nerve conduction study, interleukin-1β (IL-1ß), nerve growth factor (NGF), total antioxidant status (TAS), total oxidant status (TOS) and histopathological scores. There were no significant intergroup differences in baseline tests. SFI significantly improved in all treated groups with no significant intergroup differences. Motor amplitude improved most in MMP, LMP and MEL, respectively. Nerve conduction velocity significantly improved in MMP compared to VEH. There were no significant intergroup differences regarding serum NGF, TAS and TOS. Tissue NGF levels were higher in LMP, HMP and MEL. IL-1ß levels were significantly lower in CT and MMP. Tissue oxidative stress levels were significantly lower in treated groups compared to VEH, with no significant difference among them. MMP showed greater histopathological improvement. Melatonin combination therapy in sciatic nerve crush injury provided adequate functional improvement, superior electrophysiological and histopathological recovery compared to high-dose methylprednisolone and exhibited better anti-inflammatory activity through IL-1ß.

Effect of local epidural application of methylprednisolone acetate on time to ambulation in non-ambulatory dogs with thoracolumbar intervertebral disc disease: A prospective randomised, blinded control trial

BACKGROUND

The objective of this study was to analyse the potential benefit of the epidural application of steroids on time to ambulation in non-ambulatory dogs affected by intervertebral disc disease (IVDD) treated with decompressive surgery.

METHODS

This prospective, randomised, blinded control trial involved 41 dogs with thoracolumbar disc extrusion, which were randomly allocated into two groups. In the control group, saline was locally applied after surgical decompression of the spinal cord (n = 23). In the treatment group (n = 18), local epidural application of methylprednisolone acetate (1 mg/kg) was used. Ambulation time was the primary outcome measure, defined as the ability to take 10 independent steps.

RESULTS

The median number of days to ambulation was 7 days (range: 1‒17 days) for the control group and 3 days (range: 1‒8 days) for the treatment group. One dog from the treatment group developed discospondylitis and abscess formation.

LIMITATIONS

The study's heterogeneity in dog breeds, ages and pre-existing health conditions could affect the generalisability of the findings.

CONCLUSION

Epidural methylprednisolone acetate applied locally at the time of surgery may accelerate recovery in dogs following IVDD surgery.

The combination treatment of methylprednisolone and growth factor-rich serum ameliorates the structural and functional changes after spinal cord injury in rat

STUDY DESIGN

Preclinical pharmacology.

OBJECTIVES

Our study aims to evaluate the combined effect of Methylprednisolone (MP) and growth factor-rich serum (GFRS) on structural and functional recovery in rats following spinal cord injury (SCI).

SETTING

Shiraz University of Medical Sciences, Shiraz, Iran METHODS: Male Sprague-Dawley rats were randomly assigned to five groups: sham group (laminectomy); SCI group (the spinal cord clip compression model); SCI-MP group (30 mg/kg MP was administrated intraperitoneally (IP) immediately after SCI); SCI-GFRS group (GFRS (200 µl, IP) was administrated for six consecutive days); and SCI-MP + GFRS group (the rats received MP (30 mg/kg, IP) immediately after SCI, and GFRS (200 µl, IP) for six consecutive days). Motor function was assessed weekly using the Basso, Beattie, and Bresnahan (BBB) scale. After 4 weeks, we conducted the rotarod test, then removed and prepared the spinal cords (including the epicenter of injury) for stereological and histological estimation, and biochemical assays.

RESULTS

The results showed that MP and GFRS combining treatment enhanced functional recovery, which was associated with a decrement in lesion volume, increased spared white and gray matter volume, reduced neuronal loss, as well as decreased necrosis and hemorrhage after SCI. Moreover, administration of MP and GFRS inhibited lipid peroxidation (malondialdehyde (MDA) content), and increased antioxidant enzymes including glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) after rat SCI.

CONCLUSIONS

We suggests that the combination treatment of MP and GFRS may ameliorate the structure and functional changes following SCI by reducing oxidative stress, and increasing the level of antioxidants enzymes.

Regulation of the JAK/STAT signaling pathway in spinal cord injury: an updated review

Cytokines are involved in neural homeostasis and pathological processes associated with neuroinflammation after spinal cord injury (SCI). The biological effect of cytokines, including those associated with acute or chronic SCI pathologies, are the result of receptor-mediated signaling through the Janus kinases (JAKs) as well as the signal transducers and activators of transcription (STAT) DNA-binding protein families. Although therapies targeting at cytokines have led to significant changes in the treatment of SCI, they present difficulties in various aspects for the direct use by patients themselves. Several small-molecule inhibitors of JAKs, which may affect multiple pro-inflammatory cytokine-dependent pathways, as well as STATs, are in clinical development for the treatment of SCI. This review describes the current understanding of the JAK-STAT signaling in neuroendocrine homeostasis and diseases, together with the rationale for targeting at this pathway for the treatment of SCI.

Neuroimmunological therapies for treating spinal cord injury: Evidence and future perspectives

Spinal cord injury (SCI) has a complex pathophysiology. Following the initial physical trauma to the spinal cord, which may cause vascular disruption, hemorrhage, mechanical injury to neural structures and necrosis, a series of biomolecular cascades is triggered to evoke secondary injury. Neuroinflammation plays a major role in the secondary injury after traumatic SCI. To date, the administration of systemic immunosuppressive medications, in particular methylprednisolone sodium succinate, has been the primary pharmacological treatment. This medication is given as a complement to surgical decompression of the spinal cord and maintenance of spinal cord perfusion through hemodynamic augmentation. However, the impact of neuroinflammation is complex with harmful and beneficial effects. The use of systemic immunosuppressants is further complicated by the natural onset of post-injury immunosuppression, which many patients with SCI develop. It has been hypothesized that immunomodulation to attenuate detrimental aspects of neuroinflammation after SCI, while avoiding systemic immunosuppression, may be a superior approach. To accomplish this, a detailed understanding of neuroinflammation and the systemic immune responses after SCI is required. Our review will strive to achieve this goal by first giving an overview of SCI from a clinical and basic science context. The role that neuroinflammation plays in the pathophysiology of SCI will be discussed. Next, the positive and negative attributes of the innate and adaptive immune systems in neuroinflammation after SCI will be described. With this background established, the currently existing immunosuppressive and immunomodulatory therapies for treating SCI will be explored. We will conclude with a summary of topics that can be explored by neuroimmunology research. These concepts will be complemented by points to be considered by neuroscientists developing therapies for SCI and other injuries to the central nervous system.

hiPSC-derived NSCs effectively promote the functional recovery of acute spinal cord injury in mice

Background

Spinal cord injury (SCI) is a common disease that results in motor and sensory disorders and even lifelong paralysis. The transplantation of stem cells, such as embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs), or subsequently generated stem/progenitor cells, is predicted to be a promising treatment for SCI. In this study, we aimed to investigate effect of human iPSC-derived neural stem cells (hiPSC-NSCs) and umbilical cord-derived MSCs (huMSCs) in a mouse model of acute SCI.

Methods

Acute SCI mice model were established and were randomly treated as phosphate-buffered saline (PBS) (control group), repaired with 1 × 10⁵ hiPSC-NSCs (NSC group), and 1 × 10⁵ huMSCs (MSC group), respectively, in a total of 54 mice (n = 18 each). Hind limb motor function was evaluated in open-field tests using the Basso Mouse Scale (BMS) at days post-operation (dpo) 1, 3, 5, and 7 after spinal cord injury, and weekly thereafter. Spinal cord and serum samples were harvested at dpo 7, 14, and 21. Haematoxylin-eosin (H&E) staining and Masson staining were used to evaluate the morphological changes and fibrosis area. The differentiation of the transplanted cells in vivo was evaluated with immunohistochemical staining.

Results

The hiPSC-NSC-treated group presented a significantly smaller glial fibrillary acidic protein (GFAP) positive area than MSC-treated mice at all time points. Additionally, MSC-transplanted mice had a similar GFAP+ area to mice receiving PBS. At dpo 14, the immunostained hiPSC-NSCs were positive for SRY-related high-mobility-group (HMG)-box protein-2 (SOX2). Furthermore, the transplanted hiPSC-NSCs differentiated into GFAP-positive astrocytes and beta-III tubulin-positive neurons, whereas the transplanted huMSCs differentiated into GFAP-positive astrocytes. In addition, hiPSC-NSC transplantation reduced fibrosis formation and the inflammation level. Compared with the control or huMSC transplanted group, the group with transplantation of hiPSC-NSCs exhibited significantly improved behaviours, particularly limb coordination.

Conclusions

HiPSC-NSCs promote functional recovery in mice with acute SCI by replacing missing neurons and attenuating fibrosis, glial scar formation, and inflammation.

Graphical abstract

Effective Modulation of CNS Inhibitory Microenvironment using Bioinspired Hybrid-Nanoscaffold-Based Therapeutic Interventions

Central nervous system (CNS) injuries are often debilitating, and most currently have no cure. This is due to the formation of a neuroinhibitory microenvironment at injury sites, which includes neuroinflammatory signaling and non-permissive extracellular matrix (ECM) components. To address this challenge, a viscous interfacial self-assembly approach, to generate a bioinspired hybrid 3D porous nanoscaffold platform for delivering anti-inflammatory molecules and establish a favorable 3D-ECM environment for the effective suppression of the neuroinhibitory microenvironment, is developed. By tailoring the structural and biochemical properties of the 3D porous nanoscaffold, enhanced axonal growth from the dual-targeting therapeutic strategy in a human induced pluripotent stem cell (hiPSC)-based in vitro model of neuroinflammation is demonstrated. Moreover, nanoscaffold-based approaches promote significant axonal growth and functional recovery in vivo in a spinal cord injury model through a unique mechanism of anti-inflammation-based fibrotic scar reduction. Given the critical role of neuroinflammation and ECM microenvironments in neuroinhibitory signaling, the developed nanobiomaterial-based therapeutic intervention may pave a new road for treating CNS injuries.

In Vitro and In Vivo Pipeline for Validation of Disease-Modifying Effects of Systems Biology-Derived Network Treatments for Traumatic Brain Injury-Lessons Learned

We developed a pipeline for the discovery of transcriptomics-derived disease-modifying therapies and used it to validate treatments in vitro and in vivo that could be repurposed for TBI treatment. Desmethylclomipramine, ionomycin, sirolimus and trimipramine, identified by in silico LINCS analysis as candidate treatments modulating the TBI-induced transcriptomics networks, were tested in neuron-BV2 microglial co-cultures, using tumour necrosis factor α as a monitoring biomarker for neuroinflammation, nitrite for nitric oxide-mediated neurotoxicity and microtubule associated protein 2-based immunostaining for neuronal survival. Based on (a) therapeutic time window in silico, (b) blood-brain barrier penetration and water solubility, (c) anti-inflammatory and neuroprotective effects in vitro (p < 0.05) and (d) target engagement of Nrf2 target genes (p < 0.05), desmethylclomipramine was validated in a lateral fluid-percussion model of TBI in rats. Despite the favourable in silico and in vitro outcomes, in vivo assessment of clomipramine, which metabolizes to desmethylclomipramine, failed to demonstrate favourable effects on motor and memory tests. In fact, clomipramine treatment worsened the composite neuroscore (p < 0.05). Weight loss (p < 0.05) and prolonged upregulation of plasma cytokines (p < 0.05) may have contributed to the worsened somatomotor outcome. Our pipeline provides a rational stepwise procedure for evaluating favourable and unfavourable effects of systems-biology discovered compounds that modulate post-TBI transcriptomics.

The effects of human immunoglobulin G on enhancing tissue protection and neurobehavioral recovery after traumatic cervical spinal cord injury are mediated through the neurovascular unit

Background

Spinal cord injury (SCI) is a condition with few effective treatment options. The blood-spinal cord barrier consists of pericytes, astrocytes, and endothelial cells, which are collectively termed the neurovascular unit. These cells support spinal cord homeostasis by expressing tight junction proteins. Physical trauma to the spinal cord disrupts the barrier, which leads to neuroinflammation by facilitating immune cell migration to the damaged site in a process involving immune cell adhesion. Immunosuppressive strategies, including methylprednisolone (MPSS), have been investigated to treat SCI. However, despite some success, MPSS has the potential to increase a patient’s susceptibility to wound infection and impaired wound healing. Hence, immunomodulation may be a more attractive approach than immunosuppression. Approved for modulating neuroinflammation in certain disorders, including Guillain-Barre syndrome, intravenous administration of human immunoglobulin G (hIgG) has shown promise in the setting of experimental SCI, though the optimal dose and mechanism of action remain undetermined.

Methods

Female adult Wistar rats were subjected to moderate-severe clip compression injury (35 g) at the C7-T1 level and randomized to receive a single intravenous (IV) bolus of hIgG (0.02, 0.2, 0.4, 1, 2 g/kg), MPSS (0.03 g/kg), or control buffer at 15 min post-SCI. At 24 h and 6 weeks post-SCI, molecular, histological, and neurobehavioral effects of hIgG were analyzed.

Results

At 24 h post-injury, human immunoglobulin G co-localized with spinal cord pericytes, astrocytes, and vessels. hIgG (2 g/kg) protected the spinal cord neurovasculature after SCI by increasing tight junction protein expression and reducing inflammatory enzyme expression. Improvements in vascular integrity were associated with changes in spinal cord inflammation. Interestingly, hIgG (2 g/kg) increased serum expression of inflammatory cytokines and co-localized (without decreasing protein expression) with spinal cord vascular cell adhesion molecule-1, a protein used by immune cells to enter into inflamed tissue. Acute molecular benefits of hIgG (2 g/kg) led to greater tissue preservation, functional blood flow, and neurobehavioral recovery at 6 weeks post-SCI. Importantly, the effects of hIgG (2 g/kg) were superior to control buffer and hIgG (0.4 g/kg), and comparable with MPSS (0.03 g/kg).

Conclusions

hIgG (2 g/kg) is a promising therapeutic approach to mitigate secondary pathology in SCI through antagonizing immune cell infiltration at the level of the neurovascular unit.

Neural stem cell therapy aiming at better functional recovery after spinal cord injury

Injury to the spinal cord causes transection of axon fibers and neural cell death, resulting in disruption of the neural network and severe functional loss. Reconstruction of the damaged neural circuits was once considered to be hopeless as the adult mammalian central nervous system has very poor ability to regenerate. For this reason, there is currently no effective therapeutic treatment for spinal cord injury (SCI). However, with recent developments in stem cell research and cell culture technology, regenerative therapy using neural stem cell (NSC) transplantation has rapidly been developed, and this therapeutic strategy makes it possible to rebuild the destroyed neural circuits. In this review, we discuss the recent breakthroughs in NSC transplantation therapy for SCI. Developmental Dynamics 247:75-84, 2018. © 2017 Wiley Periodicals, Inc.

Glucocorticoid resistance in chronic diseases

Glucocorticoids are involved in several responses triggered by a variety of environmental and physiological stimuli. These hormones have a wide-range of regulatory effects in organisms. Synthetic glucocorticoids are extensively used to suppress allergic, inflammatory, and immune disorders. Although glucocorticoids are highly effective for therapeutic purposes, some patients chronically treated with glucocorticoids can develop reduced glucocorticoid sensitivity or even resistance, increasing patient vulnerability to exaggerated inflammatory responses. Glucocorticoid resistance can occur in several chronic diseases, including asthma, major depression, and cardiovascular conditions. In this review, we discuss the complexity of the glucocorticoid receptor and the potential role of glucocorticoid resistance in the development of chronic diseases.

Neuroprotective effects of safranal in a rat model of traumatic injury to the spinal cord by anti-apoptotic, anti-inflammatory and edema-attenuating

Studies on the pathology of spinal cord injury (SCI) have focused on inflammation-associated neuronal apoptosis. The traditional Chinese medicine safranal has been studied extensively and found to have various beneficial health effects. However, study of its potential role in neuroprotection and the underlying mechanism of action in SCI models has been limited. We investigated the effect of safranal on neurologic functions and histopathologic changes after SCI and the mechanism underlying its neuroprotective effects. First, the most effective safranal dose for SCI was evaluated with the Basso, Beattie, and Bresnahan Locomotor Rating Scale and H&E staining: 100mg/kg was the most effective dose of safranal for SCI. Histopathologic changes were evaluated by performing Nissl staining, which indicated an increased number of neurons after safranal administration. In terms of the mechanism of action, anti-apoptotic effect, downregulation of inflammation, and edema-attenuating effects were detected. TUNEL staining and electron microscopy revealed that safranal treatment inhibited injury-induced apoptosis, and affected the expression of the apoptosis-related genes Bax and Bcl-2, which indicated an anti-apoptotic role after SCI. Safranal treatment suppressed immunoreactivity and expression of the inflammatory cytokines IL-1β, TNF-α, and p38 MAPK, and increased expression of IL-10 after SCI, suggesting an anti-inflammatory effect. Safranal treatment suppressed expression of AQP-4, which is related to spinal-cord edema, suggesting an edema-attenuating effect. These data suggest that safranal promotes the recovery of neuronal function after SCI in rats, and that this effect is related to its anti-apoptotic, anti-inflammatory, and edema-attenuating effects.

Current therapeutic strategies for inflammation following traumatic spinal cord injury

Damage from spinal cord injury occurs in two phases – the trauma of the initial mechanical insult and a secondary injury to nervous tissue spared by the primary insult. Apart from damage sustained as a result of direct trauma to the spinal cord, the post-traumatic inflammatory response contributes significantly to functional motor deficits exacerbated by the secondary injury. Attenuating the detrimental aspects of the inflammatory response is a promising strategy to potentially ameliorate the secondary injury, and promote significant functional recovery. This review details how the inflammatory component of secondary injury to the spinal cord can be treated currently and in the foreseeable future.

Spinal cord injury induces a long-lasting upregulation of interleukin-1β in astrocytes around the central canal

Under inflammatory conditions, interleukin-1β (IL-1β) modulates neural stem cells at neurogenic niches. Here we show that spinal cord injury in rats increases IL-1β expression in astrocytes located around the spinal cord ependyma, a region that also holds a neurogenic potential. IL-1β increases from day 1 after lesion, reaches maximal levels between days 3 and 7, and declines from 14 days to low levels after 28 days. At the time of maximal expression, periependymal upregulation of IL-1β extends beyond 5 mm from the epicenter of the lesion both rostral and caudally. Since IL-1β controls proliferation and cell fate of neural stem/precursor cells, its modulation in periependymal astrocytes might create an appropriate environment for cell replacement after injury.

The effect of corticosteroid administration on soft-tissue inflammation associated with rhBMP-2 use in a rodent model of inflammation

STUDY DESIGN

In vivo rodent model.

OBJECTIVE

Investigate the effect of systemic corticosteroid administration on soft-tissue inflammation after local delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2).

SUMMARY OF BACKGROUND DATA

Corticosteroid use in cases of soft-tissue inflammation associated with the use of rhBMP-2 has been reported in clinical studies, but the effectiveness of its use and appropriate timing remain unclear.

METHODS

Absorbable collagen sponges were implanted with control or rhBMP-2 into the lumbar region of rats subcutaneously and intramuscularly. Four groups were studied: group I, control sponge only; group 2, BMP-2 sponge only; group III, BMP-2 sponge and preoperative intraperitoneal methylprednisolone (MPSS); group IV, BMP-2 sponge with MPSS given on day 2. Using magnetic resonance imaging, inflammation was assessed in terms of soft tissue edema volume at 0, 2, 4, and 7 days. Rats were sacrificed after 7 days for gross and histological analysis.

RESULTS

The peak mean intramuscular inflammatory volume occurred on day 2 in all groups. Group II (BMP-2 without MPSS) had a significantly higher peak mean inflammatory volume (405.46 mm) on day 2 than that of groups I (266 mm), III (278 mm), and IV (291 mm) (P = 0.001). No significant difference in intramuscular soft-tissue inflammation was observed between the control group and the groups receiving MPSS on day 0 or day 2 at any time point. No differences in the area of inflammatory cell infiltrate surrounding the sponge was observed histologically, after sacrificing them, in groups treated with BMP-2.

CONCLUSION

Systemic MPSS administration reduced soft tissue edema associated with rhBMP-2 as measured by magnetic resonance imaging, but no effect was observed on the histological area of inflammation. Further studies are required to elucidate if there is any benefit to the use of corticosteroid administration in reducing the area of inflammation associated with the use of rhBMP-2.

Effects of hyperbaric oxygen and dexamethasone on proinflammatory cytokines of rat cochlea in noise-induced hearing loss

HYPOTHESIS

To investigate effects of dexamethasone and hyperbaric oxygen therapy (HBOT) on proinflammatory cytokines and hearing levels in the noise-exposed cochlea of rats.

BACKGROUND

There is an arising concern about negative effects of early initiation of HBOT on hearing in noise-induced hearing loss. Furthermore, effects of HBOT and dexamethasone on cochlear cytokines are not fully elucidated.

METHODS

Twenty-six rats were divided into 3 groups: control, noise, and treatment groups. Five rats served as control group. White noise at 115 dB sound pressure level was applied to the noise group of 4 rats for 10 days. This group was assigned to a positive control group as it was equivalent to treatment groups. The treatment group of 17 rats underwent the same noise exposure, and then, they were divided into 3 groups based on treatment protocol: 5 and 6 rats received HBOT at the third hour and 24th hour after the noise, respectively, and 6 rats received dexamethasone. Auditory brain stem response threshold was measured in all groups before being assigned to the groups, after the noise exposure and right before being killed. Cytokine levels at the cochlear soft tissues were measured using enzyme-linked immunoassay.

RESULTS

Final thresholds (10 dB and 5 dB nHL-normal hearing level) of HBOT-24th hour and dexamethasone groups were significantly better than that of untreated noise group (22.5 dB nHL) (p < 0.05). There was no significant difference between HBOT-24th hour group (10 dB nHL) and dexamethasone group (5 dB nHL) (p > 0.05). IL-6 and IL-1β of HBOT-third hour group (2.30 ng/mg and 185.43 pg/mg) were significantly higher than those of the noise group (0.91 ng/mg and 131.40 pg/mg), dexamethasone group (1.19 ng/mg and 112.29 pg/mg) and HBOT-24th hour group (1.34 ng/mg and 106.69 pg/mg) (p < 0.05). There was no significant difference in IL-6 and IL-1β of HBOT-24th hour group, dexamethasone group, noise group, and control group (p > 0.05). There was no significant difference in TNF-α of the 3 treatment groups, noise group, and control group (p > 0.05).

CONCLUSION

The results showed that the most effective method in the treatment of noise-induced hearing loss was early initiation of dexamethasone therapy. There could be negative effects of HBOT on hearing if it is commenced early after the noise (first 3 h). HBOT treatment, which was started at the 24th hour, was found to be an effective method.

Inhibition of IL-6 signaling: A novel therapeutic approach to treating spinal cord injury pain

To characterize the contribution of interleukin-6 (IL-6) to spinal cord injury pain (SCIP), we employed a clinically relevant rat contusion model of SCIP. Using Western blots, we measured IL-6 levels in lumbar segments (L1-L5), at the lesion site (T10), and in the corresponding lumbar and thoracic dorsal root ganglia (DRG) in 2 groups of similarly injured rats: (a) SCI rats that developed hind-limb mechanical allodynia (SCIP), and (b) SCI rats that did not develop SCIP. Only in SCIP rats did we find significantly increased IL-6 levels. Immunocytochemistry showed elevated IL-6 predominantly in reactive astrocytes. Our data also showed that increased production of IL-6 in hyperreactive astrocytes in SCIP rats may explain still-poorly understood astrocytic contribution to SCIP. To test the hypothesis that IL-6 contributes to mechanical allodynia, we treated SCIP rats with neutralizing IL-6 receptor antibody (IL-6-R Ab), and found that one systemic injection abolished allodynia and associated weight loss; in contrast to gabapentin, the analgesic effect lasted for at least 2weeks after the injection, despite the shorter presence of the Ab in the circulation. We also showed that IL-6-R Ab partially reversed SCI-induced decreases in the protein levels of the glutamate transporter GLT-1 12hours and 8days after Ab injection, which may explain the lasting analgesic effect of the Ab in SCIP rats. A link between reactive astrocytes IL-6-GLT-1 has not been previously shown. Given that the humanized IL-6-R Ab tocilizumab is Food and Drug Administration-approved for rheumatoid arthritis, we are proposing tocilizumab as a novel and potentially effective treatment for SCIP.

The role of markers of inflammation in traumatic brain injury

Within minutes of a traumatic impact, a robust inflammatory response is elicited in the injured brain. The complexity of this post-traumatic squeal involves a cellular component, comprising the activation of resident glial cells, microglia, and astrocytes, and the infiltration of blood leukocytes. The second component regards the secretion immune mediators, which can be divided into the following sub-groups: the archetypal pro-inflammatory cytokines (Interleukin-1, Tumor Necrosis Factor, Interleukin-6), the anti-inflammatory cytokines (IL-4, Interleukin-10, and TGF-beta), and the chemotactic cytokines or chemokines, which specifically drive the accumulation of parenchymal and peripheral immune cells in the injured brain region. Such mechanisms have been demonstrated in animal models, mostly in rodents, as well as in human brain. Whilst the humoral immune response is particularly pronounced in the acute phase following Traumatic brain injury (TBI), the activation of glial cells seems to be a rather prolonged effect lasting for several months. The complex interaction of cytokines and cell types installs a network of events, which subsequently intersect with adjacent pathological cascades including oxidative stress, excitotoxicity, or reparative events including angiogenesis, scarring, and neurogenesis. It is well accepted that neuroinflammation is responsible of beneficial and detrimental effects, contributing to secondary brain damage but also facilitating neurorepair. Although such mediators are clear markers of immune activation, to what extent cytokines can be defined as diagnostic factors reflecting brain injury or as predictors of long term outcome needs to be further substantiated. In clinical studies some groups reported a proportional cytokine production in either the cerebrospinal fluid or intraparenchymal tissue with initial brain damage, mortality, or poor outcome scores. However, the validity of cytokines as biomarkers is not broadly accepted. This review article will discuss the evidence from both clinical and laboratory studies exploring the validity of immune markers as a correlate to classification and outcome following TBI.

The role of markers of inflammation in traumatic brain injury

Within minutes of a traumatic impact, a robust inflammatory response is elicited in the injured brain. The complexity of this post-traumatic squeal involves a cellular component, comprising the activation of resident glial cells, microglia, and astrocytes, and the infiltration of blood leukocytes. The second component regards the secretion immune mediators, which can be divided into the following sub-groups: the archetypal pro-inflammatory cytokines (Interleukin-1, Tumor Necrosis Factor, Interleukin-6), the anti-inflammatory cytokines (IL-4, Interleukin-10, and TGF-beta), and the chemotactic cytokines or chemokines, which specifically drive the accumulation of parenchymal and peripheral immune cells in the injured brain region. Such mechanisms have been demonstrated in animal models, mostly in rodents, as well as in human brain. Whilst the humoral immune response is particularly pronounced in the acute phase following Traumatic brain injury (TBI), the activation of glial cells seems to be a rather prolonged effect lasting for several months. The complex interaction of cytokines and cell types installs a network of events, which subsequently intersect with adjacent pathological cascades including oxidative stress, excitotoxicity, or reparative events including angiogenesis, scarring, and neurogenesis. It is well accepted that neuroinflammation is responsible of beneficial and detrimental effects, contributing to secondary brain damage but also facilitating neurorepair. Although such mediators are clear markers of immune activation, to what extent cytokines can be defined as diagnostic factors reflecting brain injury or as predictors of long term outcome needs to be further substantiated. In clinical studies some groups reported a proportional cytokine production in either the cerebrospinal fluid or intraparenchymal tissue with initial brain damage, mortality, or poor outcome scores. However, the validity of cytokines as biomarkers is not broadly accepted. This review article will discuss the evidence from both clinical and laboratory studies exploring the validity of immune markers as a correlate to classification and outcome following TBI.

Neuroprotective effects of racemic ketamine and (S)-ketamine on spinal cord injury in rat

BACKGROUND

The aim of this study was to investigate and to compare the potential neuroprotective effects of racemic ketamine, (S)-ketamine and methylprednisolone after an experimental spinal cord injury model in rats.

METHODS

Fifty-nine Wistar albino rats were divided into three main groups as acute stage (A), subacute stage (SA) and sham groups and then acute and subacute stage groups were divided into four groups regarding the used drug as control (CONT), racemic ketamine (RK), (S)-ketamine (SK) and methylprednisolone (MP) groups. A dorsal laminectomy was performed; and spinal cord injury was induced by using a temporary aneurysm clip. Four hours later from the clip compression, except those of the sham and control groups, the drugs (60 mg/kg racemic ketamine, 60 mg/kg (S)-ketamine or 30 mg/kg methylprednisolone) were administered intraperitoneally. At 72th h and 7th days of the study, the spinal cords of rats were removed from T8 level to the conus medullaris level. The specimens were and evaluated histopathologically, tissue lipid peroxidation (LPO) and myeloperoxidation (MPO) levels were measured and biochemically.

RESULTS

The histopathological results were similar both in the acute and in the subacute stage groups. There was a statistically significant difference among all groups regarding the tissue LPO levels (p<0.001). There was a statistically significant difference between the CONT-A group and the MP-A, RK-A and SK-A groups (p=0.004, p<0.001 and p=0.007, respectively) in acute stage and between the CONT-SA group and SK-SA group (p=0.002) in subacute stage. There was a statistically significant difference among all groups regarding the tissue MPO levels (p=0.001). The median MPO levels were similar among acute stage groups (p=0.057), but there was a statistical difference among subacute stage groups (p=0.046).

CONCLUSION

(S)-ketamine is more effective than methylprednisolone and racemic ketamine to reduce the LPO levels in subacute stage of spinal cord injury in rats. And, it is as effective as methylprednisolone in preventing secondary spinal cord injury histopathologically.

Interleukin-1 participates in the classical and alternative activation of microglia/macrophages after spinal cord injury

Background

Microglia and macrophages (MG/MΦ) have a diverse range of functions depending on unique cytokine stimuli, and contribute to neural cell death, repair, and remodeling during central nervous system diseases. While IL-1 has been shown to exacerbate inflammation, it has also been recognized to enhance neuroregeneration. We determined the activating phenotype of MG/MΦ and the impact of IL-1 in an in vivo spinal cord injury (SCI) model of IL-1 knock-out (KO) mice. Moreover, we demonstrated the contribution of IL-1 to both the classical and alternative activation of MG in vitro using an adult MG primary culture.

Methods

SCI was induced by transection of the spinal cord between the T9 and T10 vertebra in wild-type and IL-1 KO mice. Locomotor activity was monitored and lesion size was determined for 14 days. TNFα and Ym1 levels were monitored to determine the MG/MΦ activating phenotype. Primary cultures of MG were produced from adult mice, and were exposed to IFNγ or IL-4 with and without IL-1β. Moreover, cultures were exposed to IL-4 and/or IL-13 in the presence and absence of IL-1β.

Results

The locomotor activity and lesion area of IL-1 KO mice improved significantly after SCI compared with wild-type mice. TNFα production was significantly suppressed in IL-1 KO mice. Also, Ym1, an alternative activating MG/MΦ marker, did not increase in IL-1 KO mice, suggesting that IL-1 contributes to both the classical and alternative activation of MG/MΦ. We treated primary MG cultures with IFNγ or IL-4 in the presence and absence of IL-1β. Increased nitric oxide and TNFα was present in the culture media and increased inducible NO synthase was detected in cell suspensions following co-treatment with IFNγ and IL-1β. Expression of the alternative activation markers Ym1 and arginase-1 was increased after exposure to IL-4 and further increased after co-treatment with IL-4 and IL-1β. The phenotype was not observed after exposure of cells to IL-13.

Conclusions

We demonstrate here in in vivo experiments that IL-1 suppressed SCI in a process mediated by the reduction of inflammatory responses. Moreover, we suggest that IL-1 participates in both the classical and alternative activation of MG in in vivo and in vitro systems.

Treatment of infections of the spine

Spinal infection may involve the vertebrae, the intervertebral discs, and the adjacent intraspinal and paraspinal soft tissues. It often starts with subtle and insidious clinical signs and symptoms and may development to a debilitating and even life threatening disease. Spinal infections occur with increasing incidence and are nowadays a disease of everyday's practice for physicians treating spinal disorders. Traditionally, conservative treatment consisting of antibiosis and immobilisation is considered the first tier therapy. However, due to a considerably high rate of vertebral column instability or neurological impairment caused by the infected tissue, comprehensive experience with surgical measures have been acquired over the last decades. Thanks to tremendous improvements of surgical implants and techniques, surgical treatment has already begun to challenge conservative treatment to eventually become the first tier therapy for spinal infections in the future. This review seeks to give an overview of epidemiology, pathogenesis, diagnostic evaluation, and current nonsurgical and surgical therapy of spinal infections on the basis of the existing literature, which consists largely of retrospectively acquired data of single-centre experience with sample sizes of less than 100 patients treated with individually defined indications and treatment algorithms, and followed with various outcome parameters.

Effects of dexmedetomidine or methylprednisolone on inflammatory responses in spinal cord injury

BACKGROUND

The aim of this study was to compare the anti-inflammatory response of methylprednisolone and the alpha2-agonist dexmedetomidine in spinal cord injury (SCI).

METHODS

Twenty-four male adult Wistar albino rats, weight 200-250 g, were included in the study. The rats were divided into four groups as follows: the control group (n: 6) received only laminectomy; the SCI group (n: 6) with trauma alone; the SCI+methylprednisolone group (n: 6) with trauma and 30 mg/kg methylprednisolone, followed by a maintenance dose of 5.4 mg/kg/h; and the SCI+dexmedetomidine group (n: 6) with trauma and 10 microg/kg dexmedetomidine treatment intraperitoneally. Twenty-four hours after the trauma, spinal cord samples were taken for histopathological examination and serum samples were collected for interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha measurement.

RESULTS

TNF-alpha (P=0.009) and IL-6 (P=0.009) levels were significantly increased in the SCI group. TNF-alpha and IL-6 levels were significantly decreased with methylprednisolone (P=0.002, 0.002) and dexmedetomidine (P=0.002, 0.009) treatment, respectively. Methylprednisolone and dexmedetomidine treatment reduced neutrophils' infiltration in SCI.

CONCLUSIONS

The current study does not clarify the definitive mechanism by which dexmedetomidine decreases inflammatory cytokines but it is the first study to report the anti-inflammatory effect of dexmedetomidine in SCI. Further studies are required to elucidate the effects of dexmedetomidine on the inflammatory response.

Clip compression model is useful for thoracic spinal cord injuries: histologic and functional correlates

STUDY DESIGN

Experimental investigation of an acute thoracic spinal cord injury model in rats involving acute clip compression that simulates human injury.

OBJECTIVE

To assess the dose-response of this model for the relationship between the force of injury on the rat thoracic spinal cord and histological and functional outcome measures.

SUMMARY OF BACKGROUND DATA

Acute extradural clip compression injury has been a reliable model for producing acute experimental cervical spinal cord injury; however, this model has not been formally evaluated with dose-response curves for acute injury of the thoracic spinal cord.

METHODS

After laminectomy at T2 in Sprague-Dawley rats, a modified aneurysm clip exerting a closing force of 20, 26, or 35 g was applied extradurally around the spinal cord at T2, and then rapidly released with cord compression persisting for 1 minute. These forces were selected to simulate acute compression injuries of mild to moderate, moderate, and moderate to severe degrees, respectively (n = 8/group). Motor activity was assessed weekly for 4 weeks with the Basso, Beattie, and Bresnahan (BBB) open field locomotor test. The injured spinal cord was then examined histologically including quantification of cavitation.

RESULTS

A significant main effect was observed for clip force and BBB score (F(2,20) = 5.42, P = 0.013). For 4 weeks after injury, the BBB scores for the 20 g and 35 g clip injury groups were significantly different (P < 0.05). The cavitation volume at 4 weeks was directly proportional to the severity of injury: the 20 g group had significantly smaller cavities than the 35 g group (P < 0.05), and the cavitation volume correlated with the BBB scores.

CONCLUSION

The rat thoracic cord clip compression model is a reproducible, clinically relevant spinal cord injury model. This is the first time that the force of clip compression injury in the rat thoracic cord has been correlated with both functional and histologic outcome measures.

Reparixin, an inhibitor of CXCR2 function, attenuates inflammatory responses and promotes recovery of function after traumatic lesion to the spinal cord

It has been shown that the blockade of CXCR1 and CXCR2 receptors prevents ischemia/reperfusion damage in several types of vascular beds. Reparixin is a recently described inhibitor of human CXCR1/R2 and rat CXCR2 receptor activation. We applied reparixin in rats following traumatic spinal cord injury and determined therapeutic temporal and dosages windows. Treatment with reparixin significantly counteracts secondary degeneration by reducing oligodendrocyte apoptosis, migration to the injury site of neutrophils and ED-1-positive cells. The observed preservation of the white matter might also be secondary to the enhanced proliferation of NG2-positive cells. The expression of macrophage-inflammatory protein-2, tumor necrosis factor-alpha, interleukin (IL)-6, and IL-1 beta was also counteracted, and the proliferation of glial fibrillary acidic protein-positive cells was markedly reduced. These effects resulted in a smaller post-traumatic cavity and in a significantly improved recovery of hind limb function. The best beneficial outcome of reparixin treatment required 7-day administration either by i.p. route (15 mg/kg) or subcutaneous infusion via osmotic pumps (10 mg/kg), reaching a steady blood level of 8 microg/ml. Methylprednisolone was used as a reference drug; such treatment reduced cytokine production but failed to affect the rate of hind limb recovery.

Inflammation and its role in neuroprotection, axonal regeneration and functional recovery after spinal cord injury

Trauma to the central nervous system (CNS) triggers intraparenchymal inflammation and activation of systemic immunity with the capacity to exacerbate neuropathology and stimulate mechanisms of tissue repair. Despite our incomplete understanding of the mechanisms that control these divergent functions, immune-based therapies are becoming a therapeutic focus. This review will address the complexities and controversies of post-traumatic neuroinflammation, particularly in spinal cord. In addition, current therapies designed to target neuroinflammatory cascades will be discussed.

Therapeutic efficacy of intra-cochlear administration of methylprednisolone after acoustic trauma caused by gunshot noise in guinea pigs

The therapeutic efficacy of cochlear infusion of methylprednisolone (MP) after an impulse noise trauma (170dB SPL peak) was evaluated in guinea pigs. The compound action potential threshold shifts were measured over a 14 days recovery period after the gunshot exposure. For each animal, one of the cochlea was perfused directly into the scala tympani with MP during 7 days via a mini-osmotic pump, whereas the other cochlea was not pump-implanted. The functional study of hearing was supplemented by histological analysis. Forty eight hours after the trauma, significant differences between auditory threshold shifts in the implanted and non-implanted ears were observed for frequencies above 8kHz. At day 7, the difference was significant for only one frequency and no difference was observed after 14 days recovery. Cochleograms showed that the hair cell losses were significantly lower in the MP treated ears. This work indicates that direct infusion of MP into perilymphatic space accelerates hearing recovery, reduces hair cell losses after impulse noise trauma but does not limit permanent threshold shifts.

Recovery of function following grafting of human bone marrow-derived stromal cells into the injured spinal cord

This study evaluates functional recovery after transplanting human bone marrow-derived stromal cells (BMSCs) into contusion models of spinal cord injury (SCI). The authors used a high-throughput process to expand BMSCs and characterized them by flow cytometry, ELISA, and gene expression. They found that BMSCs secrete neurotrophic factors and cytokines with therapeutic potential for cell survival and axon growth. In adult immune-suppressed rats, mild, moderate, or severe contusions were generated using the MASCIS impactor. One week following injury, 0.5 to 1 x 106 BMSCs were injected into the lesioned spinal cord; control animals received vehicle injection. Biweekly behavioral tests included the Basso, Beattie, and Bresnahan Locomotor Rating Scale (BBB), exploratory rearing, grid walking, and thermal sensitivity. Animals receiving moderate contusions followed by BMSC grafts showed significant behavioral recovery in BBB and rearing tests when compared to controls. Animals receiving BMSC grafts after mild or severe contusion showed trends toward improved recovery. Immunocytochemistry identified numerous axons passing through the injury in animals with BMSC grafts but few in controls. BMSCS were detected at 2 weeks after transplantation; however, at 11 weeks very few grafted cells remained. The authors conclude that BMSCs show potential for repairing SCI. However, the use of carefully characterized BMSCs improved transplantation protocols ensuring BMSC, survival, and systematic motor and sensory behavioral testing to identify robust recovery is imperative for further improvement.

Nonhemorrhagic cord contusion after percutaneous fiducial placement: case report and surgical recommendations

STUDY DESIGN

Single case report and extensive literature review.

OBJECTIVES

To present the first such report of cervical cord contusion after the percutaneous placement of gold-seed fiducials. The pathomechanics and surgical recommendations are reviewed.

BACKGROUND

Spinal cord injuries are well documented in the medical literature. These injuries range from cord contusion to transection and result primarily from trauma. A single case report of a patient who was found to have a nonhemorrhagic cervical spinal cord contusion after percutaneous fiducial implantation is presented.

METHODS

Single case report.

RESULTS

The patient underwent percutaneous placement of fiducials for stereotactic radiosurgery for a nerve sheath tumor. Postoperatively she had primarily sensory complaints; no motor deficits were detected on neurological examination. Neuroimaging studies demonstrated nonhemorrhagic cervical cord contusion. She was treated conservatively and had complete resolution of her symptoms.

CONCLUSIONS

The likely mechanism for the contusion was neck hyperextension during thrusting maneuvers during fiducial implantation. This is yet another report of normal intraoperative-evoked potentials with postoperative neurological sequelae. A dedicated team approach involving ancillary staff, anesthesiologists, and surgeons should be utilized to avert this potentially devastating complication.

Methylprednisolone neutralizes the beneficial effects of erythropoietin in experimental spinal cord injury

Inflammation plays a major pathological role in spinal cord injury (SCI). Although antiinflammatory treatment using the glucocorticoid methyprednisolone sodium succinate (MPSS) improved outcomes in several multicenter clinical trials, additional clinical experience suggests that MPSS is only modestly beneficial in SCI and poses a risk for serious complications. Recent work has shown that erythropoietin (EPO) moderates CNS tissue injury, in part by reducing inflammation, limiting neuronal apoptosis, and restoring vascular autoregulation. We determined whether EPO and MPSS act synergistically in SCI. Using a rat model of contusive SCI, we compared the effects of EPO [500-5,000 units/kg of body weight (kg-bw)] with MPSS (30 mg/kg-bw) for proinflammatory cytokine production, histological damage, and motor function at 1 month after a compression injury. Although high-dose EPO and MPSS suppressed proinflammatory cytokines within the injured spinal cord, only EPO was associated with reduced microglial infiltration, attenuated scar formation, and sustained neurological improvement. Unexpectedly, coadministration of MPSS antagonized the protective effects of EPO, even though the EPO receptor was up-regulated normally after injury. These data illustrate that the suppression of proinflammatory cytokines alone does not necessarily prevent secondary injury and suggest that glucocorticoids should not be coadministered in clinical trials evaluating the use of EPO for treatment of SCI.