Meta analysis of olfactory ensheathing cell transplantation promoting functional recovery of motor nerves in rats with complete spinal cord transection

Pediatric Spinal Cord Injury: A Review

A spinal cord injury (SCI) can be a devastating condition in children, with profound implications for their overall health and quality of life. In this review, we aim to provide a concise overview of the key aspects associated with SCIs in the pediatric population. Firstly, we discuss the etiology and epidemiology of SCIs in children, highlighting the diverse range of causes. We explore the unique anatomical and physiological characteristics of the developing spinal cord that contribute to the specific challenges faced by pediatric patients. Next, we delve into the clinical presentation and diagnostic methods, emphasizing the importance of prompt and accurate diagnosis to facilitate appropriate interventions. Furthermore, we approach the multidisciplinary management of pediatric SCIs, encompassing acute medical care, surgical interventions, and ongoing supportive therapies. Finally, we explore emerging research as well as innovative therapies in the field, and we emphasize the need for continued advancements in understanding and treating SCIs in children to improve their functional independence and overall quality of life.

Heterogeneity and Potency of Peripheral Glial Cells in Embryonic Development and Adults

This review describes the heterogeneity of peripheral glial cell populations, from the emergence of Schwann cells (SCs) in early development, to their involvement, and that of their derivatives in adult glial populations. We focus on the origin of the first glial precursors from neural crest cells (NCCs), and their ability to differentiate into several cell types during development. We also discuss the heterogeneity of embryonic glia in light of the latest data from genetic tracing and transcriptome analysis. Special attention has been paid to the biology of glial populations in adult animals, by highlighting common features of different glial cell types and molecular differences that modulate their functions. Finally, we consider the communication of glial cells with axons of neurons in normal and pathological conditions. In conclusion, the present review details how information available on glial cell types and their functions in normal and pathological conditions may be utilized in the development of novel therapeutic strategies for the treatment of patients with neurodiseases.

The leading edge: Emerging neuroprotective and neuroregenerative cell-based therapies for spinal cord injury

Spinal cord injuries (SCIs) are associated with tremendous physical, social, and financial costs for millions of individuals and families worldwide. Rapid delivery of specialized medical and surgical care has reduced mortality; however, long-term functional recovery remains limited. Cell-based therapies represent an exciting neuroprotective and neuroregenerative strategy for SCI. This article summarizes the most promising preclinical and clinical cell approaches to date including transplantation of mesenchymal stem cells, neural stem cells, oligodendrocyte progenitor cells, Schwann cells, and olfactory ensheathing cells, as well as strategies to activate endogenous multipotent cell pools. Throughout, we emphasize the fundamental biology of cell-based therapies, critical features in the pathophysiology of spinal cord injury, and the strengths and limitations of each approach. We also highlight salient completed and ongoing clinical trials worldwide and the bidirectional translation of their findings. We then provide an overview of key adjunct strategies such as trophic factor support to optimize graft survival and differentiation, engineered biomaterials to provide a support scaffold, electrical fields to stimulate migration, and novel approaches to degrade the glial scar. We also discuss important considerations when initiating a clinical trial for a cell therapy such as the logistics of clinical-grade cell line scale-up, cell storage and transportation, and the delivery of cells into humans. We conclude with an outlook on the future of cell-based treatments for SCI and opportunities for interdisciplinary collaboration in the field.

Pharmacologic and cellular therapies in the treatment of traumatic spinal cord injuries: A systematic review

OBJECTIVE

The objective of this review is to synthesize and consolidate the existing literature on the treatment of SCI, focusing on drugs in development and cellular therapeutics, including stem-cell treatments.

METHODS

Studies were identified through a systemic search of PubMed, Ovid MEDLINE, Embase and the Cochrane database from their respective inceptions through January 1, 2020. We used the keywords "spinal cord injuries", "therapeutics", "stem cells", and "pharmacology."

STUDY SELECTION

Studies that assessed treatment strategies for SCI were included.

DATA EXTRACTION AND SYNTHESIS

Data on SCIs were processed according to the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) guidelines.

FINDINGS

In total, 62 articles were found in the literature search and 13 clinical trials were identified and included in this study. This review article discusses the management and treatment of SCI with an emphasis on the pharmacology, molecular approaches, and the use of stem cells. Presently, none of the treatments examined has shown to be clearly effective.

CONCLUSIONS

Present management strategies of SCI are focused on improving spinal cord perfusion and decreasing secondary injuries such as hypoxia, inflammation, edema, excitotoxicity and disturbances of ion homeostasis. This review hopes to demonstrate the significant advances made in the field of SCI and the new methodologies and practices being employed by researchers to improve our knowledge of the pathology. Our hope is that by consolidating the past and current research, improvements can be made in the management, treatment, and outcomes for these patients and other who suffer from spinal pathologies.

Controlling properties of human neural progenitor cells using 2D and 3D conductive polymer scaffolds

Human induced pluripotent stem cell-derived neural progenitor cells (hNPCs) are a promising cell source for stem cell transplantation to treat neurological diseases such as stroke and peripheral nerve injuries. However, there have been limited studies investigating how the dimensionality of the physical and electrical microenvironment affects hNPC function. In this study, we report the fabrication of two- and three-dimensional (2D and 3D respectively) constructs composed of a conductive polymer to compare the effect of electrical stimulation of hydrogel-immobilized hNPCs. The physical dimension (2D vs 3D) of stimulating platforms alone changed the hNPCs gene expression related to cell proliferation and metabolic pathways. The addition of electrical stimulation was critical in upregulating gene expression of neurotrophic factors that are important in regulating cell survival, synaptic remodeling, and nerve regeneration. This study demonstrates that the applied electrical field controls hNPC properties depending on the physical nature of stimulating platforms and cellular metabolic states. The ability to control hNPC functions can be beneficial in understanding mechanistic changes related to electrical modulation and devising novel treatment methods for neurological diseases.

Time is spine: a review of translational advances in spinal cord injury

Acute traumatic spinal cord injury (SCI) is a devastating event with far-reaching physical, emotional, and economic consequences for patients, families, and society at large. Timely delivery of specialized care has reduced mortality; however, long-term neurological recovery continues to be limited. In recent years, a number of exciting neuroprotective and regenerative strategies have emerged and have come under active investigation in clinical trials, and several more are coming down the translational pipeline. Among ongoing trials are RISCIS (riluzole), INSPIRE (Neuro-Spinal Scaffold), MASC (minocycline), and SPRING (VX-210). Microstructural MRI techniques have improved our ability to image the injured spinal cord at high resolution. This innovation, combined with serum and cerebrospinal fluid (CSF) analysis, holds the promise of providing a quantitative biomarker readout of spinal cord neural tissue injury, which may improve prognostication and facilitate stratification of patients for enrollment into clinical trials. Given evidence of the effectiveness of early surgical decompression and growing recognition of the concept that "time is spine," infrastructural changes at a systems level are being implemented in many regions around the world to provide a streamlined process for transfer of patients with acute SCI to a specialized unit. With the continued aging of the population, central cord syndrome is soon expected to become the most common form of acute traumatic SCI; characterization of the pathophysiology, natural history, and optimal treatment of these injuries is hence a key public health priority. Collaborative international efforts have led to the development of clinical practice guidelines for traumatic SCI based on robust evaluation of current evidence. The current article provides an in-depth review of progress in SCI, covering the above areas.

Clinical Trials in Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) results in impaired neurologic function that for many individuals is permanent and significantly impacts health, function, quality of life, and life expectancy. Many efforts have been taken to develop effective treatments for SCI; nevertheless, proven therapies targeting neurologic regeneration and functional recovery have been limited. Existing therapeutic approaches, including early surgery, strict blood pressure control, and consideration of treatment with steroids, remain debated and largely focus on mitigating secondary injury after the primary trauma has occurred. Today, there is more research being performed in SCI than ever before. Current clinical trials are exploring pharmacologic, cell-based, physiologic, and rehabilitation approaches to reduce secondary injury and also overcome barriers to neurorecovery. In the future, it is likely that tailored treatments combining many of these strategies will offer significant benefits for persons with SCI. This article aims to review key past, current and emerging neurologic and rehabilitation therapeutic approaches for adults with traumatic SCI.

Transplantation of olfactory ensheathing cells on functional recovery and neuropathic pain after spinal cord injury; systematic review and meta-analysis

There are considerable disagreements on the application of olfactory ensheathing cells (OEC) for spinal cord injury (SCI) rehabilitation. The present meta-analysis was designed to investigate the efficacy of OEC transplantation on motor function recovery and neuropathic pain alleviation in SCI animal models. Accordingly, all related studies were identified and included. Two independent researchers assessed the quality of the articles and summarized them by calculating standardized mean differences (SMD). OEC transplantation was shown to significantly improve functional recovery (SMD = 1.36; 95% confidence interval: 1.05–1.68; p < 0.001). The efficacy of this method was higher in thoracic injuries (SMD = 1.41; 95% confidence interval: 1.08–1.74; p < 0.001) and allogeneic transplants (SMD = 1.53; 95% confidence interval: 1.15–1.90; p < 0.001). OEC transplantation had no considerable effects on the improvement of hyperalgesia (SMD = −0.095; 95% confidence interval: −0.42–0.23; p = 0.57) but when the analyses were limited to studies with follow-up ≥8 weeks, it was associated with increased hyperalgesia (SMD = −0.66; 95% confidence interval: −1.28–0.04; p = 0.04). OEC transplantation did not affect SCI-induced allodynia (SMD = 0.54; 95% confidence interval: −0.80–1.87; p = 0.43). Our findings showed that OEC transplantation can significantly improve motor function post-SCI, but it has no effect on allodynia and might lead to relative aggravation of hyperalgesia.

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.

Synergetic effects of ciliary neurotrophic factor and olfactory ensheathing cells on optic nerve reparation (complete translation)

At present, there is no effective treatment for the repair of the optic nerve after injury, or improvement of its microenvironment for regeneration. Intravitreally injected ciliary neurotrophic factor (CNTF) and olfactory ensheathing cells (OECs) promote the long-distance regrowth of severed optic nerve fibers after intracranial injury. Here, we examined the efficacy of these techniques alone and in combination, in a rat model of optic nerve injury. We injected condensed OEC suspension at the site of injury, or CNTF into the vitreous body, or both simultaneously. Retrograde tracing techniques showed that 4 weeks postoperatively, the number of surviving retinal ganglion cells and their axonal density in the optic nerve were greater in rats subjected to OEC injection only than in those receiving CNTF injection only. Furthermore, combined OEC + CNTF injection achieved better results than either monotherapy. These findings confirm that OECs are better than CNTF at protecting injured neurons in the eye, but that combined OEC and CNTF therapy is notably more effective than either treatment alone.

Recent advances in managing a spinal cord injury secondary to trauma

Traumatic spinal cord injuries (SCIs) affect 1.3 million North Americans, producing devastating physical, social, and vocational impairment. Pathophysiologically, the initial mechanical trauma is followed by a significant secondary injury which includes local ischemia, pro-apoptotic signaling, release of cytotoxic factors, and inflammatory cell infiltration. Expedient delivery of medical and surgical care during this critical period can improve long-term functional outcomes, engendering the concept of "Time is Spine". We emphasize the importance of expeditious care while outlining the initial clinical and radiographic assessment of patients. Key evidence-based early interventions (surgical decompression, blood pressure augmentation, and methylprednisolone) are also reviewed, including findings of the landmark Surgical Timing in Acute Spinal Cord Injury Study (STASCIS). We then describe other neuroprotective approaches on the edge of translation such as the sodium-channel blocker riluzole, the anti-inflammatory minocycline, and therapeutic hypothermia. We also review promising neuroregenerative therapies that are likely to influence management practices over the next decade including chondroitinase, Rho-ROCK pathway inhibition, and bioengineered strategies. The importance of emerging neural stem cell therapies to remyelinate denuded axons and regenerate neural circuits is also discussed. Finally, we outline future directions for research and patient care.

Concise Review: Bridging the Gap: Novel Neuroregenerative and Neuroprotective Strategies in Spinal Cord Injury

Spinal cord injuries (SCIs) result in devastating lifelong disability for patients and their families. The initial mechanical trauma is followed by a damaging secondary injury cascade involving proapoptotic signaling, ischemia, and inflammatory cell infiltration. Ongoing cellular necrosis releases ATP, DNA, glutamate, and free radicals to create a cytotoxic postinjury milieu. Long-term regeneration of lost or injured networks is further impeded by cystic cavitation and the formation of an inhibitory glial-chondroitin sulfate proteoglycan scar. In this article, we discuss important neuroprotective interventions currently applied in clinical practice, including surgical decompression, blood pressure augmentation, and i.v. methylprednisolone. We then explore exciting translational therapies on the horizon, such as riluzole, minocycline, fibroblast growth factor, magnesium, and hypothermia. Finally, we summarize the key neuroregenerative strategies of the next decade, including glial scar degradation, Rho-ROCK inhibition, cell-based therapies, and novel bioengineered adjuncts. Throughout, we emphasize the need for combinatorial approaches to this multifactorial problem and discuss relevant studies at the forefront of translation. We conclude by providing our perspectives on the future direction of SCI research.

SIGNIFICANCE

Spinal cord injuries (SCIs) result in devastating, lifelong disability for patients and their families. This article discusses important neuroprotective interventions currently applied in clinical practice, including surgical decompression, blood pressure augmentation, and i.v. methylprednisolone. Translational therapies on the horizon are discussed, such as riluzole, minocycline, fibroblast growth factor, magnesium, and hypothermia. The key neuroregenerative strategies of the next decade are summarized, including glial scar degradation, Rho-ROCK inhibition, cell-based therapies, and novel bioengineered adjuncts. The need for combinatorial approaches to this multifactorial problem is emphasized, relevant studies at the forefront of translation are discussed, and perspectives on the future direction of SCI research are presented.

Taking a bite out of spinal cord injury: do dental stem cells have the teeth for it?

Dental stem cells are an emerging star on a stage that is already quite populated. Recently, there has been a lot of hype concerning these cells in dental therapies, especially in regenerative endodontics. It is fitting that most research is concentrated on dental regeneration, although other uses for these cells need to be explored in more detail. Being a true mesenchymal stem cell, their capacities could also prove beneficial in areas outside their natural environment. One such field is the central nervous system, and in particular, repairing the injured spinal cord. One of the most formidable challenges in regenerative medicine is to restore function to the injured spinal cord, and as yet, a cure for paralysis remains to be discovered. A variety of approaches have already been tested, with graft-based strategies utilising cells harbouring appropriate properties for neural regeneration showing encouraging results. Here we present a review focusing on properties of dental stem cells that endorse their use in regenerative medicine, with particular emphasis on repairing the damaged spinal cord.

Involuntary, Forced and Voluntary Exercises Equally Attenuate Neurocognitive Deficits in Vascular Dementia by the BDNF-pCREB Mediated Pathway

A rat model of vascular dementia was used to compare the effects of involuntary exercise induced by functional electrical stimulation (FES), forced exercise and voluntary exercise on the recovery of cognitive function recovery and its underlying mechanisms. In an involuntary exercise (I-EX) group, FES was used to induce involuntary gait-like running on ladder at 12 m/min. A forced exercise group (F-EX) and a voluntary exercise group (V-EX) exercised by wheel running. The Barnes maze was used for behavioral assessment. Brain-derived neurotrophic factor (BDNF), phosphorylated extracellular signal-regulated kinase 1 and 2 (ERK1/2) and cAMP response element binding protein (CREB) positive cells in hippocampal CA1, CA2/3 and dentate gyrus (DG) regions were evaluated using immunohistochemical methods. Western blotting was used to assess the levels of BDNF, phosphorylated protein kinase B (Akt), tropomyosin receptor kinase B (TrkB), mitogen-activated protein kinase 1 and 2 (MEK1/2), ERK1/2 and CREB in BDNF-pCREB signaling in the hippocampus and prefrontal cortex. Involuntary, forced and voluntary exercises were all found to reverse the cognitive deficits of vascular dementia with about equal effectiveness. The number of BDNF, pCREB and pERK1/2 immunopositive cells was significantly increased in the hippocampal CA1, CA2/3 and DG regions in all three exercise groups. In addition, involuntary exercise activated BDNF and the phosphorylation of Akt, TrkB, MEK1/2, ERK1/2 and CREB in the hippocampus and prefrontal cortex equally as well as voluntary or forced exercise. These results suggest that involuntary exercise induced by FES may be as beneficial for alleviating cognitive deficits after cerebral ischemia.