Tree shrew neural stem cell transplantation promotes functional recovery of tree shrews with a hemi‑sectioned spinal cord injury by upregulating nerve growth factor expression

Advances in spinal cord injury: insights from non-human primates

Spinal cord injury results in significant sensorimotor deficits, currently, there is no curative treatment for the symptoms induced by spinal cord injury. Basic and pre-clinical research on spinal cord injury relies on the development and characterization of appropriate animal models. These models should replicate the symptoms observed in human, allowing for the exploration of functional deficits and investigation into various aspects of physiopathology of spinal cord injury. Non-human primates, due to their close phylogenetic association with humans, share more neuroanatomical, genetic, and physiological similarities with humans than rodents. Therefore, the responses to spinal cord injury in nonhuman primates most likely resemble the responses to traumatism in humans. In this review, we will discuss nonhuman primate models of spinal cord injury, focusing on in vivo assessments, including behavioral tests, magnetic resonance imaging, and electrical activity recordings, as well as ex vivo histological analyses. Additionally, we will present therapeutic strategies developed in non-human primates and discuss the unique specificities of non-human primate models of spinal cord injury.

Advances in Neural Stem Cell Therapy for Spinal Cord Injury: Safety, Efficacy, and Future Perspectives

Spinal cord injury (SCI) is a devastating central nervous system injury that leads to severe disabilities in motor and sensory functions, causing significant deterioration in patients' quality of life. Owing to the complexity of SCI pathophysiology, there has been no effective treatment for reversing neural tissue damage and recovering neurological functions. Several novel therapies targeting different stages of pathophysiological mechanisms of SCI have been developed. Among these, treatments using stem cells have great potential for the regeneration of damaged neural tissues. In this review, we have summarized recent preclinical and clinical studies focusing on neural stem cells (NSCs). NSCs are multipotent cells with specific differentiation capabilities for neural lineage. Several preclinical studies have demonstrated the regenerative effects of transplanted NSCs in SCI animal models through both paracrine effects and direct neuronal differentiation, restoring synaptic connectivity and neural networks. Based on the positive results of several preclinical studies, phase I and II clinical trials using NSCs have been performed. Despite several hurdles and issues that need to be addressed in the clinical use of NSCs in patients with SCI, gradual progress in the technical development and therapeutic efficacy of NSCs treatments has enhanced the prospects for cell-based treatments in SCI.

Regulating Endogenous Neural Stem Cell Activation to Promote Spinal Cord Injury Repair

Spinal cord injury (SCI) affects millions of individuals worldwide. Currently, there is no cure, and treatment options to promote neural recovery are limited. An innovative approach to improve outcomes following SCI involves the recruitment of endogenous populations of neural stem cells (NSCs). NSCs can be isolated from the neuroaxis of the central nervous system (CNS), with brain and spinal cord populations sharing common characteristics (as well as regionally distinct phenotypes). Within the spinal cord, a number of NSC sub-populations have been identified which display unique protein expression profiles and proliferation kinetics. Collectively, the potential for NSCs to impact regenerative medicine strategies hinges on their cardinal properties, including self-renewal and multipotency (the ability to generate de novo neurons, astrocytes, and oligodendrocytes). Accordingly, endogenous NSCs could be harnessed to replace lost cells and promote structural repair following SCI. While studies exploring the efficacy of this approach continue to suggest its potential, many questions remain including those related to heterogeneity within the NSC pool, the interaction of NSCs with their environment, and the identification of factors that can enhance their response. We discuss the current state of knowledge regarding populations of endogenous spinal cord NSCs, their niche, and the factors that regulate their behavior. In an attempt to move towards the goal of enhancing neural repair, we highlight approaches that promote NSC activation following injury including the modulation of the microenvironment and parenchymal cells, pharmaceuticals, and applied electrical stimulation.

Stem Cell Transplantation: A Promising Therapy for Spinal Cord Injury

Spinal Cord Injury (SCI) causes irreversible functional loss of the affected population. The incidence of SCI keeps increasing, resulting in huge burden on the society. The pathogenesis of SCI involves neuron death and exotic reaction, which could impede neuron regeneration. In clinic, the limited regenerative capacity of endogenous cells after SCI is a major problem. Recent studies have demonstrated that a variety of stem cells such as induced Pluripotent Stem Cells (iPSCs), Embryonic Stem Cells (ESCs), Mesenchymal Stem Cells (MSCs) and Neural Progenitor Cells (NPCs) /Neural Stem Cells (NSCs) have therapeutic potential for SCI. However, the efficacy and safety of these stem cellbased therapy for SCI remain controversial. In this review, we introduce the pathogenesis of SCI, summarize the current status of the application of these stem cells in SCI repair, and discuss possible mechanisms responsible for functional recovery of SCI after stem cell transplantation. Finally, we highlight several areas for further exploitation of stem cells as a promising regenerative therapy of SCI.

Efficacy of neural stem cell transplantation for the treatment of patients with spinal cord injury: A protocol of systematic review and meta-analysis

BACKGROUND

The aim of this study is to evaluate the efficacy of neural stem cell transplantation (NSCT) for the treatment of patients with spinal cord injury (SCI).

METHODS

All potential randomized controlled trials (RCTs) on NSCT in the treatment of patients with SCI will be searched from the following electronic databases: Cochrane Library, MEDILINE, EMBASE, Web of Science, Scopus, CBM, WANGFANG, and CNKI. We will search all electronic databases from their initiation to the January 31, 2020 in spite of language and publication date. Two contributors will independently select studies from all searched literatures, extract data from included trials, and evaluate study quality for all eligible RCTs using Cochrane risk of bias tool, respectively. Any confusion will be resolved by consulting contributor and a consensus will be reached. We will utilize RevMan 5.3 software to pool the data and to conduct the data analysis.

RESULTS

This study will summarize the most recent RCTs to investigate the efficacy and safety of NSCT in the treatment of patients with SCI.

CONCLUSION

This study will provide evidence to assess the efficacy and safety of NSCT in the treatment of patients with SCI at evidence-based medicine level.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020173792.

Establishment of Neurobehavioral Assessment System in Tree Shrew SCT Model

Tree shrews, possessing higher developed motor function than rats, were more suitable to study neurological behavior after spinal cord injury (SCI). Here, we established a feasible behavioral assessment method to detect the degree of ethology recovery in tree shrew subjected to spinal cord transection (SCT). Tree shrews were divided into normal group, sham group, and SCT group. The tree shrew in sham group was subjected to laminectomy without SCI, while the tree shrews in the SCT group were subjected to a complete SCT in thoracic 10 (T10). A novel neurobehavior assessment scale was established, in which, the behavior index including slow advancement, fast advancement, standing, shaking head, voluntary jump, lateral movement, and tail status, was determined, respectively. Meanwhile, magnetic resonance imaging (MRI) was applied to observe the structure of the spinal cord, and diffusion tensor imaging (DTI)-based white matter mapping was used to show the fibers of the spinal cord. As a result, a marked decrease in locomotor function and consciousness was seen in tree shrews with SCT, and the detection of MRI showed the collapsing of nerve fibers after SCT is completely cut and there is corresponding to the behavior change. Together, the present study provided a novel and feasible method that can be used to assess the neurobehavior in SCT model from tree shrews, which may be useful to the SCI translational study in future preclinic trial.

Filling the Gap: Neural Stem Cells as A Promising Therapy for Spinal Cord Injury

Spinal cord injury (SCI) can lead to severe motor, sensory and social impairments having a huge impact on patients’ lives. The complex and time-dependent SCI pathophysiology has been hampering the development of novel and effective therapies. Current treatment options include surgical interventions, to stabilize and decompress the spinal cord, and rehabilitative care, without providing a cure for these patients. Novel therapies have been developed targeting different stages during trauma. Among them, cell-based therapies hold great potential for tissue regeneration after injury. Neural stem cells (NSCs), which are multipotent cells with inherent differentiation capabilities committed to the neuronal lineage, are especially relevant to promote and reestablish the damaged neuronal spinal tracts. Several studies demonstrate the regenerative effects of NSCs in SCI after transplantation by providing neurotrophic support and restoring synaptic connectivity. Therefore, human clinical trials have already been launched to assess safety in SCI patients. Here, we review NSC-based experimental studies in a SCI context and how are they currently being translated into human clinical trials.

Subcutaneous Maturation of Neural Stem Cell-Loaded Hydrogels Forms Region-Specific Neuroepithelium

A combinatorial approach integrating stem cells and capable of exploiting available cues is likely needed to regenerate lost neural tissues and ultimately restore neurologic functions. This study investigates the effects of the subcutaneous maturation of adult-derived neural stem cell (aNSCs) seeded into biomaterial constructs on aNSC differentiation and ultimate regional neuronal identity as a first step toward a future spinal cord injury treatment. To achieve this, we encapsulated rat aNSCs in chitosan-based hydrogels functionalized with immobilized azide-tagged interferon-γ inside a chitosan conduit. Then, we implanted these constructs in the subcutaneous tissues in the backs of rats in the cervical, thoracic, and lumbar regions for 4, 6, and 8 weeks. After harvesting the scaffolds, we analyzed cell differentiation qualitatively using immunohistochemical analysis and quantitatively using RT-qPCR. Results revealed that the hydrogels supported aNSC survival and differentiation up to 4 weeks in the subcutaneous environment as marked by the expression of several neurogenesis markers. Most interesting, the aNSCs expressed region-specific Hox genes corresponding to their region of implantation. This study lays the groundwork for further translational work to recapitulate the potentially undiscovered patterning cues in the subcutaneous tissue and provide support for the conceptual premise that our bioengineering approach can form caudalized region-specific neuroepithelium.