The role of GM1-ganglioside in the injured spinal cord of rats: an immunohistochemical study using GM1-antisera

Novel Methods of Necroptosis Inhibition for Spinal Cord Injury Using Translational Research to Limit Secondary Injury and Enhance Endogenous Repair and Regeneration

Spinal cord injuries (SCIs) pose an immense challenge from a clinical perspective as current treatments and interventions have been found to provide marginal improvements in clinical outcome (with varying degrees of success) particularly in areas of motor and autonomic function. In this review, the pathogenesis of SCI will be described, particularly as it relates to the necroptotic pathway which has been implicated in limiting recovery of SCI via its roles in neuronal cell death, glial scarring, inflammation, and axonal demyelination and degeneration. Major mediators of the necroptotic pathway including receptor-interacting protein kinase 1, receptor-interacting protein kinase 3, and mixed-lineage kinase domain-like will be described in detail regarding their role in facilitating necroptosis. Additionally, due to the rapid accumulation of reactive oxygen species and inflammatory markers, the onset of necroptosis can begin within hours following SCI, thus developing therapeutics that readily cross the blood-brain barrier and inhibit necroptosis during these critical periods of inflammation are imperative in preventing irreversible damage. As such, current therapeutic interventions regarding SCI and targeting of the necroptotic pathway will be explored as will discussion of potential future therapeutics that show promise in minimizing long-term or permanent damage to the spinal cord following severe injury.

Update on Spinal Cord Injury Management

The management of acute spinal cord injury requires a multidisciplinary approach to maximize patient outcomes and potential. Treatment of this injury involves both surgical and medical intervention. Medical intervention in acute spinal cord injury is aimed at decreasing the neurotoxic environment that occurs as part of the secondary injury. New neuroregenerative therapies are being developed.

Traumatic Spinal Cord Injury-Repair and Regeneration

BACKGROUND

Traumatic spinal cord injuries (SCI) have devastating consequences for the physical, financial, and psychosocial well-being of patients and their caregivers. Expediently delivering interventions during the early postinjury period can have a tremendous impact on long-term functional recovery.

PATHOPHYSIOLOGY

This is largely due to the unique pathophysiology of SCI where the initial traumatic insult (primary injury) is followed by a progressive secondary injury cascade characterized by ischemia, proapoptotic signaling, and peripheral inflammatory cell infiltration. Over the subsequent hours, release of proinflammatory cytokines and cytotoxic debris (DNA, ATP, reactive oxygen species) cyclically adds to the harsh postinjury microenvironment. As the lesions mature into the chronic phase, regeneration is severely impeded by the development of an astroglial-fibrous scar surrounding coalesced cystic cavities. Addressing these challenges forms the basis of current and upcoming treatments for SCI.

MANAGEMENT

This paper discusses the evidence-based management of a patient with SCI while emphasizing the importance of early definitive care. Key neuroprotective therapies are summarized including surgical decompression, methylprednisolone, and blood pressure augmentation. We then review exciting neuroprotective interventions on the cusp of translation such as Riluzole, Minocycline, magnesium, therapeutic hypothermia, and CSF drainage. We also explore the most promising neuroregenerative strategies in trial today including Cethrin™, anti-NOGO antibody, cell-based approaches, and bioengineered biomaterials. Each section provides a working knowledge of the key preclinical and patient trials relevant to clinicians while highlighting the pathophysiologic rationale for the therapies.

CONCLUSION

We conclude with our perspectives on the future of treatment and research in this rapidly evolving field.

Current and future medical therapeutic strategies for the functional repair of spinal cord injury

Spinal cord injury (SCI) leads to social and psychological problems in patients and requires costly treatment and care. In recent years, various pharmacological agents have been tested for acute SCI. Large scale, prospective, randomized, controlled clinical trials have failed to demonstrate marked neurological benefit in contrast to their success in the laboratory. Today, the most important problem is ineffectiveness of nonsurgical treatment choices in human SCI that showed neuroprotective effects in animal studies. Recently, attempted cellular therapy and transplantations are promising. A better understanding of the pathophysiology of SCI started in the early 1980s. Research had been looking at neuroprotection in the 1980s and the first half of 1990s and regeneration studies started in the second half of the 1990s. A number of studies on surgical timing suggest that early surgical intervention is safe and feasible, can improve clinical and neurological outcomes and reduce health care costs, and minimize the secondary damage caused by compression of the spinal cord after trauma. This article reviews current evidence for early surgical decompression and nonsurgical treatment options, including pharmacological and cellular therapy, as the treatment choices for SCI.

Anti-inflammatory and anti-apoptotic effect of combined treatment with methylprednisolone and amniotic membrane mesenchymal stem cells after spinal cord injury in rats

This study was undertaken to investigate the synergistic effects of methylprednisolone (MP) administration and transplantation of amniotic membrane mesenchymal stem cells (AM-MSCs) following T11 spinal cord clip compressive injury in rats. The combination treatment with MP (50 mg/kg) and delayed transplantation of AM-MSCs after rat spinal cord injury, significantly reduced (1) myeloperoxidase activity, (2) the proinflammatory cytokines: tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-17, interferon-γ and (3) the cell apoptosis [terminal deoxynucleotidyl transferase, dUTP nick end labeling (TUNEL) staining, and caspase-3, Bax and Bcl-2 expressions]; increased: (1) the levels of the anti-inflammatory cytokines (IL-10 and transforming growth factor-β1) and (2) the survival rate of AM-MSCs in the injury site. The combination therapy significantly ameliorated the recovery of limb function (evaluated by Basso, Beattie and Bresnahan score). Taken together, our results demonstrate that MP in combination with AM-MSCs transplantation is a potential strategy for reducing secondary damage and promoting functional recovery following spinal cord injury.

An Appraisal of Ongoing Experimental Procedures in Human Spinal Cord Injury

Clinicians and scientists in the field of spinal cord injury research and medicine are poised to begin translating promising new experimental findings into treatments for people. Advances in experimental regeneration research have led to several transplantation strategies that promote axonal regrowth and partial functional recovery in animal models of injury. In this review, we summarize current knowledge regarding various invasive experimental treatments that have been or are now being applied clinically. Various questions about the timeliness, safety, and benefits of the procedures are under discussion within the spinal cord injury (SCI) research community. We also describe guidelines for carrying out optimal clinical trials and efforts to establish specific international guidelines to translate preclinical treatment strategies into clinical trials in SCI. The clinical trial process and the role that clinical professionals have in advising individuals regarding participation in experimental procedures also is discussed.

Acute spinal cord injury, part II: contemporary pharmacotherapy

Spinal cord injury (SCI) remains a common and devastating problem of modern society. Through an understanding of underlying pathophysiologic mechanisms involved in the evolution of SCI, treatments aimed at ameliorating neural damage may be developed. The possible pharmacologic treatments for acute spinal cord injury are herein reviewed. Myriad treatment modalities, including corticosteroids, 21-aminosteroids, opioid receptor antagonists, gangliosides, thyrotropin-releasing hormone (TRH) and TRH analogs, antioxidants and free radical scavengers, calcium channel blockers, magnesium replacement therapy, sodium channel blockers, N -methyl-D-aspartate receptor antagonists, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-kainate receptor antagonists, modulators of arachadonic acid metabolism, neurotrophic growth factors, serotonin antagonists, antibodies against inhibitors of axonal regeneration, potassium channel blockers (4-aminopyridine), paclitaxel, clenbuterol, progesterone, gabexate mesylate, activated protein C, caspase inhibitors, tacrolimus, antibodies against adhesion molecules, and other immunomodulatory therapy have been studied to date. Although most of these agents have shown promise, only one agent, methylprednisolone, has been shown to provide benefit in large clinical trials. Given these data, many individuals consider methylprednisolone to be the standard of care for the treatment of acute SCI. However, this has not been established definitively, and questions pertaining to methodology have emerged regarding the National Acute Spinal Cord Injury Study trials that provided these conclusions. Additionally, the clinical significance (in contrast to statistical significance) of recovery after methylprednisolone treatment is unclear and must be considered in light of the potential adverse effects of such treatment. This first decade of the new millennium, now touted as the Decade of the Spine, will hopefully witness the emergence of universal and efficacious pharmacologic therapy and ultimately a cure for SCI.

Protein kinase inhibition by fasudil hydrochloride promotes neurological recovery after spinal cord injury in rats

OBJECT

In Japan fasudil hydrochloride (HA1077), a protein kinase inhibitor, is widely administered to prevent vasospasm in patients after subarachnoid hemorrhage. The effects of fasudil on experimental spinal cord injury (SCI) were investigated and compared with those obtained using methylprednisolone.

METHODS

Spinal cord contusion was induced in rats by applying an aneurysm clip extradurally to the spinal cord at T-3 for 1 minute. After injury three groups of rats were treated with intravenously administered saline (control), intraperitoneally administered fasudil (10 mg/kg), or intravenously administered methylprednisolone (four 30 mg/kg injections). Neurological recovery was evaluated periodically over 1 month by using a modified combined behavioral scale and histopathological examination. Leukocyte infiltration near the injury site was evaluated by measuring myeloperoxidase (MPO) activity at 24 hours. Spinal cord blood flow was measured at intervals up to 3 hours after injury by using laser Doppler flowmetry. In rats in the fasudil-treated group significant improvement in modified combined behavioral score was demonstrated at each time point, whereas in the methylprednisolone-treated rats no beneficial effects were shown. In the fasudil-treated group, reduction of traumatic spinal cord damage was evident histologically in the caudal portion of the injured areas, and tissue MPO activity in tissue samples was reduced. Spinal cord blood flow was not significantly different between fasudil-treated and control group rats.

CONCLUSIONS

Fasudil hydrochloride showed promise of effectiveness in promoting neurological recovery after traumatic SCI. Possible mechanisms of this effect include protein kinase inhibition and decreased infiltration by neutrophils.

Combined treatment with alphaMSH and methylprednisolone fails to improve functional recovery after spinal injury in the rat

To date, relatively little progress has been made in the treatment of spinal cord injury (SCI)-related neurological impairments. Until now, methylprednisolone (MP) is the only agent with clinically proven beneficial effect on functional outcome after SCI. Although the mechanism of action is not completely clear, experimental data point to protection against membrane peroxidation and edema reduction. The melanocortin melanotropin is known to improve axonal regeneration following sciatic nerve injury, and to stimulate corticospinal outgrowth after partial spinal cord transection. Recently, we showed that intrathecally administered alphaMSH had beneficial effects on functional recovery after experimental SCI. Since both drugs have shown their value in intervention studies after (experimental) spinal cord injury (ESCI), we decided to study the effects of combined treatment. Our results again showed that alphaMSH enhances functional recovery after ESCI in the rat and that MP, although not affecting functional recovery adversely by itself, abolished the effects observed with alphaMSH when combined. Our data, thus, suggest that the mechanism of action of MP interferes with that of alphaMSH.

Anaesthetic considerations for acute spinal cord injury

The recently published research data on the possible pathophysiology of acute spinal cord injury provide the basis of a number of exciting possibilities for its treatment. The present article reviews these lines of investigation. It focusses on methylprednisolone, which is the only effective proven therapy to limit secondary spinal cord injury known to date. In addition, the initial evaluation of patients with possible spinal cord trauma and airway management in patients with cervical spine injury are also discussed. Finally, the anaesthetic regimen in patients with these injuries is reviewed, showing that no anaesthetic agent or technique is superior to other anaesthetic methods.