Cellular treatments for spinal cord injury: the time is right for clinical trials

Fighting for recovery on multiple fronts: The past, present, and future of clinical trials for spinal cord injury

Through many decades of preclinical research, great progress has been achieved in understanding the complex nature of spinal cord injury (SCI). Preclinical research efforts have guided and shaped clinical trials, which are growing in number by the year. Currently, 1,149 clinical trials focused on improving outcomes after SCI are registered in the U.S. National Library of Medicine at ClinicalTrials.gov. We conducted a systematic analysis of these SCI clinical trials, using publicly accessible data downloaded from ClinicalTrials.gov. After extracting all available data for these trials, we categorized each trial according to the types of interventions being tested and the types of outcomes assessed. We then evaluated clinical trial characteristics, both globally and by year, in order to understand the areas of growth and change over time. With regard to clinical trial attributes, we found that most trials have low enrollment, only test single interventions, and have limited numbers of primary outcomes. Some gaps in reporting are apparent; for instance, over 75% of clinical trials with "Completed" status do not have results posted, and the Phase of some trials is incorrectly classified as "Not applicable" despite testing a drug or biological compound. When analyzing trials based on types of interventions assessed, we identified the largest representation in trials testing rehab/training/exercise, neuromodulation, and behavioral modifications. Most highly represented primary outcomes include motor function of the upper and lower extremities, safety, and pain. The most highly represented secondary outcomes include quality of life and pain. Over the past 15 years, we identified increased representation of neuromodulation and rehabilitation trials, and decreased representation of drug trials. Overall, the number of new clinical trials initiated each year continues to grow, signifying a hopeful future for the clinical treatment of SCI. Together, our work provides a comprehensive glimpse into the past, present, and future of SCI clinical trials, and suggests areas for improvement in clinical trial reporting.

Three-dimensional bioprinting sodium alginate/gelatin scaffold combined with neural stem cells and oligodendrocytes markedly promoting nerve regeneration after spinal cord injury

Accumulating research has indicated that the transplantation of combined stem cells and scaffolds is an effective method for spinal cord injury (SCI). The development of three-dimensional (3D) bioprinting technology can make the 3D scaffolds combined with cells more accurate and effective for SCI treatment. However, unmyelinated newborn nerve fibers have no nerve signaling conduction, hampering recovery of motor function. In this study, we designed and printed a type of sodium alginate/gelatin scaffold loaded with neural stem cells and oligodendrocytes, which were involved in the formation of the myelin sheaths of neural cell axons. In order to observe the effectiveness of this 3D bioprinting scaffold, we transplanted it into the completely transected rat spinal cord, and then immunofluorescence staining, hematoxylin–eosin staining and behavioral assessment were performed. The results showed that this 3D bioprinting scaffold markedly improved the hindlimb motor function and promoted nerve regeneration. These findings suggested that this novel 3D bioprinting scaffold was a good carrier for cells transplantation, thereby enhancing spinal cord repair following injury.

Combining cell therapy with human autologous Schwann cell and bone marrow-derived mesenchymal stem cell in patients with subacute complete spinal cord injury: safety considerations and possible outcomes

Background

Cellular transplantations have promising effects on treating spinal cord injury (SCI) patients. Mesenchymal stem cells (MSCs) and Schwann cells (SCs), which have safety alongside their complementary characteristics, are suggested to be the two of the best candidates in SCI treatment. In this study, we assessed the safety and possible outcomes of intrathecal co-transplantation of autologous bone marrow MSC and SC in patients with subacute traumatic complete SCI.

Methods

Eleven patients with complete SCI (American Spinal Injury Association Impairment Scale (AIS); grade A) were enrolled in this study during the subacute period of injury. The patients received an intrathecal autologous combination of MSC and SC and were followed up for 12 months. We assessed the neurological changes by the American Spinal Injury Association’s (ASIA) sensory-motor scale, functional recovery by spinal cord independence measure (SCIM-III), and subjective changes along with adverse events (AE) with our checklist. Furthermore, electromyography (EMG), nerve conduction velocity (NCV), magnetic resonance imaging (MRI), and urodynamic study (UDS) were conducted for all the patients at the baseline, 6 months, and 1 year after the intervention.

Results

Light touch AIS score alterations were approximately the same as the pinprick changes (11.6 ± 13.1 and 12 ± 13, respectively) in 50% of the cervical and 63% of the lumbar-thoracic patients, and both were more than the motor score alterations (9.5 ± 3.3 in 75% of the cervical and 14% of the lumbar-thoracic patients). SCIM III total scores (21.2 ± 13.3) and all its sub-scores (“respiration and sphincter management” (15 ± 9.9), “mobility” (9.5 ± 13.3), and “self-care” (6 ± 1.4)) had statistically significant changes after cell injection. Our findings support that the most remarkable positive, subjective improvements were in trunk movement, equilibrium in standing/sitting position, the sensation of the bladder and rectal filling, and the ability of voluntary voiding. Our safety evaluation revealed no systemic complications, and radiological images showed no neoplastic overgrowth, syringomyelia, or pseudo-meningocele.

Conclusion

The present study showed that autologous SC and bone marrow-derived MSC transplantation at the subacute stage of SCI could reveal statistically significant improvement in sensory and neurological functions among the patients. It appears that using this combination of cells is safe and effective for clinical application to spinal cord regeneration during the subacute period.

Inflammatory Response to Spinal Cord Injury and Its Treatment

Spinal cord injury (SCI), as one of the intractable diseases in clinical medicine, affects thousands of human beings, and the pathologic changes after injury have been a hot spot for exploration in clinical medicine. With the development of new treatments, the survival of patients has shown an increasing trend; however, the inflammatory response after injury has not yet been effectively controlled. SCI is divided into primary injury and secondary injury according to the time of injury and pathophysiologic changes. Primary injury occurs immediately and the damage to the injury site is irreversible; however, secondary injury occurs after primary injury and involves pathologic changes at the cellular and molecular levels, which are reversible. Thus, the inflammatory response from secondary injuries has become the main direction of research. In recent years, a complex pathophysiologic mechanism has gradually been unveiled, which has been followed by an upgrade of treatment methods. This article describes the mechanisms of the inflammatory response after SCI and the mainstream treatment modalities. Also, neuroprotective agents and nerve regeneration agent agents are commonly used in the treatment of SCI; the therapeutic mechanism and classification of these agents are reviewed.

Effects of combination treatment with transcranial magnetic stimulation and bone marrow mesenchymal stem cell transplantation or Raf inhibition on spinal cord injury in rats

Spinal cord injury (SCI) remains a global challenge due to limited treatment strategies. Transcranial magnetic stimulation (TMS), bone marrow mesenchymal stem cell (BMSC) transplantation and downregulation of Raf/MEK/ERK signaling effectively improve SCI. The combination of BMSCs and TMS displays synergistic effects on vascular dementia. However, whether TMS displays a synergistic effect when combined with BMSC transplantation or Raf inhibitor (RafI) therapy for the treatment of SCI is not completely understood. The present study aimed to compare the therapeutic effect of monotherapy and combination therapy on SCI. In the present study, 8‑week‑old female Sprague Dawley rats were used to establish a model of SCI using the weight‑drop method followed by treatment with monotherapy (TMS, BMSCs or RafI) or combination therapy (TMS+BMSCs or TMS+RafI). The effect of monotherapy and combination therapy on locomotor function, pathological alterations, neuronal apoptosis and expression of axonal regeneration‑associated factors and Raf/MEK/ERK signaling‑associated proteins in the spinal cord was analyzed by Basso, Beattie and Bresnahan (BBB) scoring, hematoxylin and eosin staining, TUNEL‑neuronal nuclei (NeuN) staining and immunofluorescence or western blotting, respectively. The results demonstrated that compared with untreated SCI model rats, monotherapy significantly enhanced locomotor functional recovery, as evidenced by higher BBB scores, and slightly alleviated histopathological lesions of the spinal cord in SCI model rats. Furthermore, monotherapy markedly suppressed neuronal apoptosis and promoted axonal regeneration, as well as inhibiting astroglial activation in SCI model rats. The aforementioned results were demonstrated by significantly decreased numbers of apoptotic neurons, markedly decreased expression levels of glial fibrillary acidic protein (GFAP), significantly increased numbers of NeuN+ cells, markedly increased expression levels of growth‑associated protein 43 (GAP‑43) and significantly upregulated nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) expression levels in monotherapy groups (excluding the RafI monotherapy group) compared with untreated SCI model rats. In addition, monotherapy markedly suppressed activation of the Raf/MEK/ERK signaling pathway, as evidenced by significantly reduced p‑Raf/Raf, p‑MEK/MEK and p‑ERK/ERK protein expression levels in monotherapy groups (excluding the BMSC monotherapy group) compared with untreated SCI model rats. Notably, combination therapy further alleviated SCI‑induced spinal cord lesions and neuronal apoptosis, increased GAP‑43, NGF and BDNF expression levels, downregulated GFAP expression levels and inhibited activation of the Raf/MEK/ERK signaling pathway in SCI model rats compared with the corresponding monotherapy groups. Therefore, it was hypothesized that compared with monotherapy, combination therapy displayed an improved therapeutic effect on SCI by further suppressing Raf/MEK/ERK signaling. The results of the present study provided an important basis for the clinical application of combination therapy.

Injury-induced Cavl-expressing cells at lesion rostral side play major roles in spinal cord regeneration

The extent of cellular heterogeneity involved in neuronal regeneration after spinal cord injury (SCI) remains unclear. Therefore, we established stress-responsive transgenic zebrafish embryos with SCI. As a result, we found an SCI-induced cell population, termed SCI stress-responsive regenerating cells (SrRCs), essential for neuronal regeneration post-SCI. SrRCs were mostly composed of subtypes of radial glia (RGs-SrRCs) and neuron stem/progenitor cells (NSPCs-SrRCs) that are able to differentiate into neurons, and they formed a bridge across the lesion and connected with neighbouring undamaged motor neurons post-SCI. Compared to SrRCs at the caudal side of the SCI site (caudal-SrRCs), rostral-SrRCs participated more actively in neuronal regeneration. After RNA-seq analysis, we discovered that caveolin 1 (cav1) was significantly upregulated in rostral-SrRCs and that cav1 was responsible for the axonal regrowth and regenerative capability of rostral-SrRCs. Collectively, we define a specific SCI-induced cell population, SrRCs, involved in neuronal regeneration, demonstrate that rostral-SrRCs exhibit higher neuronal differentiation capability and prove that cav1 is predominantly expressed in rostral-SrRCs, playing a major role in neuronal regeneration after SCI.

Harnessing the Secretome of Mesenchymal Stromal Cells for Traumatic Spinal Cord Injury: Multicell Comparison and Assessment of In Vivo Efficacy

Cell therapy offers significant promise for traumatic spinal cord injury (SCI), which despite many medical advances, has limited treatment strategies. Able to address the multifactorial and dynamic pathophysiology of SCI, cells present various advantages over standard pharmacological approaches. However, the use of live cells is also severely hampered by logistical and practical considerations. These include specialized equipment and expertise, standardization of cell stocks, sustained cell viability post-thawing, and cryopreservation-induced delayed-onset cell death. For this reason, we suggest a novel and clinically translatable alternative to live-cell systemic infusion, which retains the efficacy of the latter while overcoming many of its limitations. This strategy involves the administration of concentrated cell secretome and exploits the trophic mechanism by which stromal cells function. In this study, we compare the efficacy of intravenously delivered concentrated conditioned media (CM) from human umbilical cord matrix cells (HUCMCs), bone marrow mesenchymal stromal cells, as well as newborn and adult fibroblasts in a rat model of moderately severe cervical clip compression/contusion injury (C7--T1, 35 g). This is further paired with a thorough profile of the CM cytokines, chemokines, and angiogenic factors. The HUCMC-derived CM was most effective at limiting acute (48 h post-SCI) vascular pathology, specifically lesion volume, and functional vascularity. Principle component analysis (PCA), hierarchical clustering, and interaction analysis of proteins highly expressed in the HUCMC secretome suggest involvement of the MAPK/ERK, JAK/STAT, and immune cell migratory pathways. This "secretotherapeutic" strategy represents a novel and minimally invasive method to target multiple organ systems and several pathologies shortly after traumatic SCI.

Alterations in the fecal microbiota of patients with spinal cord injury

Objectives

Spinal cord injury (SCI) is associated with severe autonomic dysfunction. Patients with SCI often suffer from a lack of central nervous system control over the gastrointestinal system. Therefore, we hypothesized that patients with SCI would cause intestinal flora imbalance. We investigated alterations in the fecal microbiome in a group of patients with SCI.

Methods

Microbial communities in the feces of 23 patients and 23 healthy controls were investigated using high-throughput Illumina Miseq sequencing targeting the V3-V4 region of the 16S ribosomal RNA (rRNA) gene. The relative abundances between the fecal microbiota at the genus level in patients with SCI and healthy individuals were determined using cluster analysis.

Results

The structure and quantity of fecal microbiota differed significantly between patients with SCI and healthy controls, but the richness and diversity were not significantly different. A two-dimensional heatmap showed that the relative abundances of forty-five operational taxonomic units (OTUs) were significantly enriched either in SCI or healthy samples. Among these, 18 OTUs were more abundant in healthy controls than in patients with SCI, and 27 OTUs were more abundant in the SCI group than in healthy controls.

Conclusion

Our study showed that patients with SCI exhibited microbiome dysbiosis.

A combinatorial approach for spinal cord injury repair using multifunctional collagen-based matrices: development, characterization and impact on cell adhesion and axonal growth

Spinal cord injury is a devastating condition of the central nervous system, in which traditional treatments are largely ineffective due to the complex nature of the injured tissue. Therefore, biomaterial-based systems have been developed as possible alternative strategies to repair the damaged tissue. In the present study, we aimed to design bioactive agent loaded scaffolds composed of two layers with distinct physical properties to improve tissue regeneration. An electrospun layer with aligned nanofibers was made of collagen (Col) Type-I, poly(lactide-co-glycolide) (PLGA) and laminin to promote cell attachment of mesenchymal-like stem cells towards the direction of fibers, while a Col-based second layer was fabricated by plastic compression to act as a releasing system for NT-3 and chondroitinase ABC, so that axonal growth could be stimulated. Results showed that a source of mesenchymal stem cell (MSC)-like cells, adipose tissue-derived stem cells cultured on the fibrous layer of the matrices were able to adhere and proliferate, where the aligned fibers promoted the cell growth in an organized way. Furthermore, the bilayered matrices also promoted dorsal root ganglion neurite outgrowth. The bilayered matrice with Col/PLGA + laminin top layer appears to promote higher neurite growth. Collectively, the designed constructs show promising structural properties and biological performance for being employed as a scaffold for engineering the spinal cord tissue.

Effects of combined treatment of minocycline and methylprednisolone on the expression of tumor necrosis factor alpha and interleukine-6 in experimental spinal cord injury: a light and electron microscopic study

Spinal cord injury (SCI) is an important health problem, and there is no universal treatment protocol for it today. Following SCI pro-inflammatory mediators such as tumor necrosis factor- alpha (TNF-α) and interleukin-6 (IL-6) increase at the lesion site and play important roles in secondary tissue damage. Methylprednisolone (MP) is a glucocorticoid, and minocycline is a tetracycline-derived antibiotic both with neuroprotective effects on central nervous system trauma. However, there are limited studies on their effects on SCI. In this study, we aimed to evaluate effects of MP+minocycline combined treatment on cellular distribution and localization of TNF-α And IL-6 after SCI. Eighty Wistar rats were divided into three main groups as the intact control group, sham operation group, and experimental control group that received spinal cord compression injury. Following the injury, the experimental control group was subdivided into four groups as control, methylprednisolone treatment, minocycline treatment and, MP+minocycline combined treatment groups. Tissue samples were obtained from all groups at 24 hours and 72 hours after the injury. We found a significant decrease in TNF-α And IL-6 expressions in combined treatment group at 24 hours after injury. Also, there was a significant decrease in MDA and increase in SOD levels in this group. Furthermore, decreased lipid peroxidation and neuronal and glial cell death were also observed in combined treatment group. These results suggest that MP+minocycline combined treatment promotes functional recovery and, it should be considered as an effective treatment protocol following SCI.

Wnt4-modified NSC transplantation promotes functional recovery after spinal cord injury

Spinal cord injury (SCI) can lead to severe motor and sensory dysfunction, yet there are no effective therapies currently due to the failure of reconstructing the interruption of the neuroanatomical circuit. While neural stem cell (NSC) transplantation has been considered a potential strategy to repair the neural circuit after SCI, the efficacy of this strategy remains unproven. The main reason is that most of the transplanted NSC differentiates into astrocyte rather than neuron in the microenvironment of SCI. Our results demonstrated that Wnt4 significantly promotes the differentiation of NSC into neuron by activating both β-catenin and MAPK/JNK pathways and suppressing the activation of Notch signaling, which is acknowledged as prevention of NSC differentiation into neuron, through downregulating NICD expression, translocating and preventing the combination of NICD and RbpJ in nucleus. In addition, Wnt4 rescues the negative effect of Jagged, the ligand of Notch signaling, to promote neuronal differentiation. Moreover, in vivo study, transplantation of Wnt4-modified NSC efficaciously repairs the injured spinal cord and recovers the motor function of hind limbs after SCI. This study sheds new light into mechanisms that Wnt4-modified NSC transplantation is sufficient to repair the injured spinal cord and recover the motor dysfunction after SCI.

Efficacy of human HC016 cell transplants on neuroprotection and functional recovery in a rat model of acute spinal cord injury

Spinal cord injury (SCI) is a devastating event with huge personal and social costs, for which there is no effective treatment. Cell therapy constitutes a promising therapeutic approach for SCI; however, its clinical potential is seriously limited by their low survival in the hostile conditions encompassing the acute phase of SCI. Human HC016 (hHC016) cells, generated from expanded human adipose mesenchymal stem cells (hAMSCs) and pulsed with a patented protocol with hydrogen peroxide (H₂ O₂ ), are expected to acquire improved resistance to oxidative environments which appears as a major limiting factor hampering the engrafting success. Our specific aim was to assess whether H₂ O₂ -pulsed hHC016 cells had an improved survival and thus therapeutic efficacy in a rat contusion model of acute SCI when grafted 48 hr after injury. Functional recovery was evaluated up to 56 days post-injury (dpi) by locomotor (open field test and CatWalk) and sensory (Von Frey and Hargreaves) tests. Besides, histological evaluation of transplanted cell survival and tissue protection/regeneration was also performed. Functional results showed a statistically significant improvement on locomotor recovery outcomes with hHC016 cells. Accordingly, superior cell survival in correlation with long-term neuroprotection, higher axonal regeneration, and reduced astroglial and microglial reactivity was also observed with hHC016 cells. These results demonstrate an enhanced survival capacity of hHC016 cells resulting in improved functional and histological outcomes as compared with hAMSCs, indicating that hHC016 cell transplants may constitute a promising cell therapy for acute SCI.

Human Induced Pluripotent Stem Cells : Clinical Significance and Applications in Neurologic Diseases

The generation of human induced pluripotent stem cells (iPSCs) from somatic cells using gene transfer opens new areas for precision medicine with personalized cell therapy and encourages the discovery of essential platforms for targeted drug development. iPSCs retain the genome of the donor, may regenerate indefinitely, and undergo differentiation into virtually any cell type of interest using a range of published protocols. There has been enormous interest among researchers regarding the application of iPSC technology to regenerative medicine and human disease modeling, in particular, modeling of neurologic diseases using patient-specific iPSCs. For instance, Parkinson’s disease, Alzheimer’s disease, and spinal cord injuries may be treated with iPSC therapy or replacement tissues obtained from iPSCs. In this review, we discuss the work so far on generation and characterization of iPSCs and focus on recent advances in the use of human iPSCs in clinical setting.

Differentiation of human adipose-derived stem cells into neuron/motoneuron-like cells for cell replacement therapy of spinal cord injury

Human adipose-derived stem cells (hADSCs) are increasingly presumed to be a prospective stem cell source for cell replacement therapy in various degenerative and/or traumatic diseases. The potential of trans-differentiating hADSCs into motor neuron cells indisputably provides an alternative way for spinal cord injury (SCI) treatment. In the present study, a stepwise and efficient hADSC trans-differentiation protocol with retinoic acid (RA), sonic hedgehog (SHH), and neurotrophic factors were developed. With this protocol hADSCs could be converted into electrophysiologically active motoneuron-like cells (hADSC-MNs), which expressed both a cohort of pan neuronal markers and motor neuron specific markers. Moreover, after being primed for neuronal differentiation with RA/SHH, hADSCs were transplanted into SCI mouse model and they survived, migrated, and integrated into injured site and led to partial functional recovery of SCI mice. When ablating the transplanted hADSC-MNs harboring HSV-TK-mCherry overexpression system with antivirial Ganciclovir (GCV), functional relapse was detected by motor-evoked potential (MEP) and BMS assays, implying that transplanted hADSC-MNs participated in rebuilding the neural circuits, which was further confirmed by retrograde neuronal tracing system (WGA). GFP-labeled hADSC-MNs were subjected to whole-cell patch-clamp recording in acute spinal cord slice preparation and both action potentials and synaptic activities were recorded, which further confirmed that those pre-conditioned hADSCs indeed became functionally active neurons in vivo. As well, transplanted hADSC-MNs largely prevented the formation of injury-induced cavities and exerted obvious immune-suppression effect as revealed by preventing astrocyte reactivation and favoring the secretion of a spectrum of anti-inflammatory cytokines and chemokines. Our work suggests that hADSCs can be readily transformed into MNs in vitro, and stay viable in spinal cord of the SCI mouse and exert multi-therapeutic effects by rebuilding the broken circuitry and optimizing the microenvironment through immunosuppression.

Employing Endogenous NSCs to Promote Recovery of Spinal Cord Injury

Endogenous neural stem cells (NSCs) exist in the central canal of mammalian spinal cords. Under normal conditions, these NSCs remain quiescent and express FoxJ1. After spinal cord injury (SCI), the endogenous NSCs of a heterogeneous nature are activated and proliferate and migrate towards the lesion site and mainly differentiate into astrocytes to repair the injured tissue. In vitro, spinal cord NSCs are multipotent and can differentiate into neurons, astrocytes, and oligodendrocytes. The altered microenvironments after SCI play key roles on the fate determination of activated NSCs, especially on the neuronal specification potential. Studies show that the activated spinal cord NSCs can generate interneurons when transplanted into the adult hippocampus. In addition, the spinal cord NSCs exhibit low immunogenicity in a transplantation context, thus implicating a promising therapeutic potential on SCI recovery. Here, we summarize the characteristics of spinal cord NSCs, especially their properties after injury. With a better understanding of endogenous NSCs under normal and SCI conditions, we may be able to employ endogenous NSCs for SCI repair in the future.

Thymosin beta 4 attenuates oxidative stress-induced injury of spinal cord-derived neural stem/progenitor cells through the TLR4/MyD88 pathway

Neural stem/progenitor cells (NSPCs) can enhance regeneration after spinal cord injury (SCI), but survival of transplanted cells remains poor. Understanding how NSPCs respond to the chemical mediators of secondary injury thus is essential for treating SCI. Thymosin β4 (Tβ4) has physiological functions that are highly relevant to SCI. We exposed NSPCs to oxidative stress and found reduced expression of Tβ4 in H₂O₂-injured NSPCs. Using an MTT assay, we found that Tβ4 dose dependently increased viability of the injured NSPCs. Tβ4 also reversed the decreases of intracellular Ca²⁺ concentration and increases of lactate dehydrogenase in NSPCs induced by H₂O₂ treatment. H₂O₂ exposure increased NSPC apoptosis, which Tβ4 decreased. In H₂O₂-induced NSPCs, ROS production and pro-inflammatory cytokines increased, and again, Tβ4 reversed these effects. We investigated the toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) signaling pathway as an underlying mechanism in Tβ4's protective effect on H₂O₂-exposed NSPCs. Our results showed that Tβ4 reduced expression of TLR4 and MyD88. Moreover, H₂O₂-exposed NSPCs that were treated with the TLR4/MyD88 pathway inhibitor showed a reversal of all the effects caused by H₂O_2, similar to Tβ4's effects. In conclusion, our study determined that Tβ4 attenuated H₂O₂-induced oxidative stress injury in NSPCs via the TLR4/MyD88 pathway.

Early Intravenous Infusion of Mesenchymal Stromal Cells Exerts a Tissue Source Age-Dependent Beneficial Effect on Neurovascular Integrity and Neurobehavioral Recovery After Traumatic Cervical Spinal Cord Injury

Localized vascular disruption after traumatic spinal cord injury (SCI) triggers a cascade of secondary events, including inflammation, gliosis, and scarring, that can further impact recovery. In addition to immunomodulatory and neurotrophic properties, mesenchymal stromal cells (MSCs) possess pericytic characteristics. These features make MSCs an ideal candidate for acute cell therapy targeting vascular disruption, which could reduce the severity of secondary injury, enhance tissue preservation and repair, and ultimately promote functional recovery. A moderately severe cervical clip compression/contusion injury was induced at C7‐T1 in adult female rats, followed by an intravenous tail vein infusion 1 hour post‐SCI of (a) term‐birth human umbilical cord perivascular cells (HUCPVCs); (b) first‐trimester human umbilical cord perivascular cells (FTM HUCPVCs); (c) adult bone marrow mesenchymal stem cells; or (d) vehicle control. Weekly behavioral testing was performed. Rats were sacrificed at 24 hours or 10 weeks post‐SCI and immunohistochemistry and ultrasound imaging were performed. Both term and FTM HUCPVC‐infused rats displayed improved (p < .05) grip strength compared with vehicle controls. However, only FTM HUCPVC‐infusion led to significant weight gain. All cell infusion treatments resulted in reduced glial scarring (p < .05). Cell infusion also led to increased axonal, myelin, and vascular densities (p < .05). Although post‐traumatic cavity volume was reduced with cell infusion, this did not reach significance. Taken together, we demonstrate selective long‐term functional recovery alongside histological improvements with HUCPVC infusion in a clinically relevant model of cervical SCI. Our findings highlight the potential of these cells for acute therapeutic intervention after SCI.

Spinal Cord-derived Neural Precursor Cells as a Preventive Therapy for Spinal Cord Injury

Background:

Spinal cord injury (SCI) as one of the most important diseases of central nervous system (CNS) without any definite treatment is still growing in incidence. In addition to trauma, some surgeries such as cardiac and thoracic aorta surgery may result in SCI as a complication. In last years, a promising approach has shed light on this CNS injury thanks to stem cell technology. Stem cell therapy could be considered as a good candidate for transplantation and enhancing neural regeneration in SCI. In this study, we identified the effects of spinal cord-derived neural precursor cells (NPCs) transplantation on SCI in after and before injury injection.

Materials and Methods:

NPCs were isolated from the adult rat spinal cord and cultured in vitro using complete culture media. After neurosphere formation, the cells were differentiated to neurons, oligodendrocytes, and astrocyte. The cells were transplanted to the rat model of SCI in 1 day before and 1 day after injury. The animals were followed for 12 weeks to assess their neurological performance. In addition, histological study and inflammatory cytokines levels have been studied.

Results:

Our results indicate that NPCs infusion both pre- and post-SCI could decrease the level of inflammatory cytokines. In addition, the neurological performance and histologic studies showed recovery after this type of injury using NPCs, and it might be due to inflammation modulatory effects on neural stem cells.

Conclusion:

NPCs therapy for SCI in both two-time points (before and after SCI) could be beneficial and make a neurological recovery. In other words, NPCs therapy could be considered as a therapeutic and also preventive approach for SCI.

Methylprednisolone inhibits the proliferation of endogenous neural stem cells in nonhuman primates with spinal cord injury

OBJECTIVE

The aim of this work was to investigate the effects of methylprednisolone on the proliferation of endogenous neural stem cells (ENSCs) in nonhuman primates with spinal cord injury (SCI).

METHODS

A total of 14 healthy cynomolgus monkeys (Macaca fascicularis) (4–5 years of age) were randomly divided into 3 groups: the control group (n = 6), SCI group (n = 6), and methylprednisolone therapy group (n = 2). Only laminectomy was performed in the control animals at T-10. SCI was induced in monkeys using Allen’s weight-drop method (50 mm × 50 g) to injure the posterior portion of the spinal cord at T-10. In the methylprednisolone therapy group, monkeys were intravenously infused with methylprednisolone (30 mg/kg) immediately after SCI. All animals were intravenously infused with 5-bromo-2-deoxyuridine (BrdU) (50 mg/kg/day) for 3 days prior to study end point. The small intestine was dissected for immunohistochemical examination. After 3, 7, and 14 days, the spinal cord segments of the control and SCI groups were dissected to prepare frozen and paraffin sections. The proliferation of ENSCs was evaluated using BrdU and nestin immunofluorescence staining.

RESULTS

Histological examination showed that a larger number of mucosa epithelial cells in the small intestine of all groups were BrdU positive. Nestin-positive ependymal cells are increased around the central canal after SCI. After 3, 7, and 14 days of SCI, BrdU-positive ependymal cells in the SCI group were significantly increased compared with the control group, and the percentage of BrdU-positive cells in the left/right ventral horns and dorsal horn was significantly higher than that of the control group. Seven days after SCI, the percentages of both BrdU-positive ependymal cells around the central canal and BrdU– and nestin–double positive cells in the left/right ventral horns and dorsal horn were significantly lower in the methylprednisolone therapy group than in the SCI group.

CONCLUSIONS

While ENSCs proliferate significantly after SCI in nonhuman primates, methylprednisolone can inhibit the proliferation of ependymal cells after SCI.

Epidermal neural crest stem cell-derived glia enhance neurotrophic elements in an ex vivo model of spinal cord injury

Growing evidence that cell-based therapies can improve recovery outcome in spinal cord injury (SCI) models substantiates their application for treatment of human with SCI. To address the effectiveness of these stem cells, potential candidates should be evaluated in proper SCI platform that allows direct real-time monitoring. In this study, the role of epidermal neural crest stem cells (EPI-NCSCs) was elucidated in an ex vivo model of SCI, and valproic acid (VPA) was administered to ameliorate the inhospitable context of injury for grafted EPI-NCSCs. Here the contusion was induced in organotypic spinal cord slice culture at day seven in vitro using a weight drop device and one hour post injury the GFP- expressing EPI-NCSCs were grafted followed by VPA administration. The evaluation of treated slices seven days after injury revealed that grafted stem cells survived on the injured slices and expressed GFAP, whereas they did not express any detectable levels of the neural progenitor marker doublecortin (DCX), which was expressed prior to transplantation. Immunoblotting data demonstrated that the expression of GFAP, BDNF, neurotrophin-3 (NT3), and Bcl2 increased significantly in stem cell treated slices. This study illustrated that the fate of transplanted stem cells has been directed to the glial lineage in the ex vivo context of injury and EPI-NCSCs may ameliorate the SCI condition through releasing neurotrophic factors directly and/or via inducing resident spinal cord cells.

Fibroblast growth factors in the management of spinal cord injury

Spinal cord injury (SCI) possesses a significant health and economic burden worldwide. Traumatic SCI is a devastating condition that evolves through two successive stages. Throughout each of these stages, disturbances in ionic homeostasis, local oedema, ischaemia, focal haemorrhage, free radicals stress and inflammatory response were observed. Although there are no fully restorative cures available for SCI patients, various molecular, cellular and rehabilitative therapies, such as limiting local inflammation, preventing secondary cell death and enhancing the plasticity of local circuits in the spinal cord, were described. Current preclinical studies have showed that fibroblast growth factors (FGFs) alone or combination therapies utilizing cell transplantation and biomaterial scaffolds are proven effective for treating SCI in animal models. More importantly, some studies further demonstrated a paucity of clinical transfer usage to promote functional recovery of numerous patients with SCI. In this review, we focus on the therapeutic capacity and pitfalls of the FGF family and its clinical application for treating SCI, including the signalling component of the FGF pathway and the role in the central nervous system, the pathophysiology of SCI and the targets for FGF treatment. We also discuss the challenges and potential for the clinical translation of FGF-based approaches into treatments for SCI.

Clinical translation of stem cell based interventions for spinal cord injury - Are we there yet?

Recent advances in basic science in research related to spinal cord injury (SCI) and regeneration have led to a variety of novel experimental therapeutics designed to promote functionally effective axonal regrowth and sprouting. Stem cell and other cellular interventions have gained lot of attention due to their immense potential of regeneration. These interventions have been tested for their efficacy in case of SCI both at the pre-clinical and clinical level. In this review we critically discuss the published literature on the cellular interventions for SCI and their clinical applications with respect to the strength of evidence established by these studies. The need to curb unethical practice of offering unproven stem cell "therapies" for SCI at a global level is also discussed.

RhoA Inhibitor Treatment At Acute Phase of Spinal Cord Injury May Induce Neurite Outgrowth and Synaptogenesis

The therapeutic use of RhoA inhibitors (RhoAi) has been experimentally tested in spinal cord injury (SCI). In order to decipher the underlying molecular mechanisms involved in such a process, an in vitro neuroproteomic-systems biology platform was developed in which the pan-proteomic profile of the dorsal root ganglia (DRG) cell line ND7/23 DRG was assessed in a large array of culture conditions using RhoAi and/or conditioned media obtained from SCI ex vivo derived spinal cord slices. A fine mapping of the spatio-temporal molecular events of the RhoAi treatment in SCI was performed. The data obtained allow a better understanding of regeneration/degeneration induced above and below the lesion site. Results notably showed a time-dependent alteration of the transcription factors profile along with the synthesis of growth cone-related factors (receptors, ligands, and signaling pathways) in RhoAi treated DRG cells. Furthermore, we assessed in a rat SCI model the in vivo impact of RhoAi treatment administered in situ via alginate scaffold that was combined with FK506 delivery. The improved recovery of locomotion was detected only at the early postinjury time points, whereas after overall survival a dramatic increase of synaptic contacts on outgrowing neurites in affected segments was observed. We validate these results by in vivo proteomic studies along the spinal cord segments from tissue and secreted media analyses, confirming the increase of the synaptogenesis expression factors under RhoAi treatment. Taken together, we demonstrate that RhoAi treatment seems to be useful to stimulate neurite outgrowth in both in vitro as well in vivo environments. However, for in vivo experiments there is a need for sustained delivery regiment to facilitate axon regeneration and promote synaptic reconnections with appropriate target neurons also at chronic phase, which in turn may lead to higher assumption for functional improvement.

Cellular therapies in trauma and critical care medicine: Looking towards the future

Shibani Pati and Todd Rasmussen summarize progress in preclinical research on cellular therapeutics for traumatic injury and its sequelae and discuss prospects for clinical translation.

Neuronal regeneration after acute spinal cord injury in adult rats

BACKGROUND CONTEXT

The most common causes of spinal cord injury (SCI) are traumatic traffic accidents, falls, and violence. Spinal cord injury greatly affects a patient's mental and physical conditions and causes substantial economic impact to society. There are many methods, such as high doses of corticosteroids, surgical stabilization, decompression, and stem cell transplantation, for functional recovery after SCI, but the effect is still not satisfactory.

PURPOSE

This study investigated the role of neuronal regeneration and the location of the neuronal regeneration after SCI in rats.

STUDY DESIGN

This is an experimental animal study of acute spinal cord injury investigating the neuronal regeneration after SCI. Double immunofluorescence staining of NF-200 and BrdU was performed to detect the location of the neuronal regeneration.

METHODS

Forty-five adult Wistar rats were tested. Allen hit model (10 g) induced acute SCI sites targeted at the T10 segments. Nestin expression was detected via immunohistochemistry. Double immunofluorescence staining of neurofilament 200 (NF-200) and 5-bromo-2'-deoxyuridine (BrdU) was performed 10 mm away from the spinal cord center. Neural functional recovery was determined using the Basso, Beattie, and Bresnahan (BBB) score and electro-physiological examination. The study was funded by the Natural Science Foundation of China (NSFC, 81272172). The funder of this study had no capacity to influence the scholarly conduct of the research, interpretation of results, or dissemination of study outcomes.

RESULTS

BrdU- and NF-200-positive cells were rarely detected and absent at 3 weeks and 4 weeks, respectively. We also detected the BrdU and NF-200 co-expressed cells are at 3 to 5 mm away from the injured site, and no co-expressed cells were detected at the injured site in this SCI model. The BBB score and electro-physiological examination of the nervous system were significantly different at 4 weeks.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate that neurons are regenerated 3 to 5 mm away from the injured site, and no neurons are regenerated at the injured site in this SCI model, which suggests a novel train of thought on SCI treatment.

Cellular Therapies in Trauma and Critical Care Medicine: Forging New Frontiers

Trauma is a leading cause of death in both military and civilian populations worldwide. Although medical advances have improved the overall morbidity and mortality often associated with trauma, additional research and innovative advancements in therapeutic interventions are needed to optimize patient outcomes. Cell-based therapies present a novel opportunity to improve trauma and critical care at both the acute and chronic phases that often follow injury. Although this field is still in its infancy, animal and human studies suggest that stem cells may hold great promise for the treatment of brain and spinal cord injuries, organ injuries, and extremity injuries such as those caused by orthopedic trauma, burns, and critical limb ischemia. However, barriers in the translation of cell therapies that include regulatory obstacles, challenges in manufacturing and clinical trial design, and a lack of funding are critical areas in need of development. In 2015, the Department of Defense Combat Casualty Care Research Program held a joint military–civilian meeting as part of its effort to inform the research community about this field and allow for effective planning and programmatic decisions regarding research and development. The objective of this article is to provide a “state of the science” review regarding cellular therapies in trauma and critical care, and to provide a foundation from which the potential of this emerging field can be harnessed to mitigate outcomes in critically ill trauma patients.

Phase 1 Trial of Autologous Bone Marrow Stem Cell Transplantation in Patients with Spinal Cord Injury

Introduction. A total of 18 patients, with complete motor deficits and paraplegia caused by thoracic and lumbar spine trauma without muscle atrophy or psychiatric problems, were included into this study. Materials and Methods. The bone marrow was aspirated from the anterior iliac crest under local anesthesia and the mononuclear fraction was isolated by density gradient method. At least 750 million mononuclear-enriched cells, suspended in 2 mL of saline, were infused intrathecally. Results and Discussion. The study reports demonstrated improvement of motor and sensory functions of various degrees observed in 9 of the 18 (50%) cases after bone marrow stem cell transplantation. Measured by the American Spinal Injury Association (ASIA) scale, 7 (78%) out of the 9 patients observed an improvement by one grade, while two cases (22%) saw an improvement by two grades. However, there were no cases in which the condition was improved by three grades. Conclusions. Analysis of subsequent treatment results indicated that the transplantation of mononuclear-enriched autologous BMSCs is a feasible and safe technique. However, successful application of the BMSCs in the clinical practice is associated with the necessity of executing more detailed examinations to evaluate the effect of BMSCs on the patients with spinal cord injury.

Proteomic Analysis of the Spatio-temporal Based Molecular Kinetics of Acute Spinal Cord Injury Identifies a Time- and Segment-specific Window for Effective Tissue Repair

Spinal cord injury (SCI) represents a major debilitating health issue with a direct socioeconomic burden on the public and private sectors worldwide. Although several studies have been conducted to identify the molecular progression of injury sequel due from the lesion site, still the exact underlying mechanisms and pathways of injury development have not been fully elucidated. In this work, based on OMICs, 3D matrix-assisted laser desorption ionization (MALDI) imaging, cytokines arrays, confocal imaging we established for the first time that molecular and cellular processes occurring after SCI are altered between the lesion proximity, i.e. rostral and caudal segments nearby the lesion (R1-C1) whereas segments distant from R1-C1, i.e. R2-C2 and R3-C3 levels coexpressed factors implicated in neurogenesis. Delay in T regulators recruitment between R1 and C1 favor discrepancies between the two segments. This is also reinforced by presence of neurites outgrowth inhibitors in C1, absent in R1. Moreover, the presence of immunoglobulins (IgGs) in neurons at the lesion site at 3 days, validated by mass spectrometry, may present additional factor that contributes to limited regeneration. Treatment in vivo with anti-CD20 one hour after SCI did not improve locomotor function and decrease IgG expression. These results open the door of a novel view of the SCI treatment by considering the C1 as the therapeutic target.

Applications of the Keap1-Nrf2 system for gene and cell therapy

Oxidative stress has been implicated to play a role in a number of acute and chronic diseases including acute injuries of the central nervous system, neurodegenerative and cardiovascular diseases, and cancer. The redox-activated transcription factor Nrf2 has been shown to protect many different cell types and organs from a variety of toxic insults, whereas in many cancers, unchecked Nrf2 activity increases the expression of cytoprotective genes and, consequently, provides growth advantage to cancerous cells. Herein, we discuss current preclinical gene therapy approaches to either increase or decrease Nrf2 activity with a special reference to neurological diseases and cancer. In addition, we discuss the role of Nrf2 in stem cell therapy for neurological disorders.

Organotypic Spinal Cord Culture: a Proper Platform for the Functional Screening

Recent improvements in organotypic slice culturing and its accompanying technological innovations have made this biological preparation increasingly useful ex vivo experimental model. Among organotypic slice cultures obtained from various central nervous regions, spinal cord slice culture is an absorbing model that represents several unique advantages over other current in vitro and in vivo models. The culture of developing spinal cord slices, as allows real-time observation of embryonic cells behaviors, is an instrumental platform for developmental investigation. Importantly, due to the ability of ex vivo models to recapitulate different aspects of corresponding in vivo conditions, these models have been subject of various manipulations to derive disease-relevant slice models. Moreover spinal cord slice cultures represent a potential platform for screening of different pharmacological agents and evaluation of cell transplantation and neuroregenerative materials. In this review, we will focus on studies carried out using the ex vivo model of spinal cord slice cultures and main advantages linked to practicality of these slices in both normal and neuropathological diseases and summarize them in different categories based on application.

Hair follicle stem cells: In vitro and in vivo neural differentiation

Hair follicle stem cells (HFSCs) normally give rise to keratinocytes, sebocytes, and transient amplifying progenitor cells. Along with the capacity to proliferate rapidly, HFSCs provide the basis for establishing a putative source of stem cells for cell therapy. HFSCs are multipotent stem cells originating from the bulge area. The importance of these cells arises from two important characteristics, distinguishing them from all other adult stem cells. First, they are accessible and proliferate for long periods. Second, they are multipotent, possessing the ability to differentiate into mesodermal and ectodermal cell types. In addition to a developmental capacity in vitro, HFSCs display an ability to form differentiated cells in vivo. During the last two decades, numerous studies have led to the development of an appropriate culture condition for producing various cell lineages from HFSCs. Therefore, these stem cells are considered as a novel source for cell therapy of a broad spectrum of neurodegenerative disorders. This review presents the current status of human, rat, and mouse HFSCs from both the cellular and molecular biology and cell therapy perspectives. The first section of this review highlights the importance of HFSCs and in vitro differentiation, while the final section emphasizes the significance of cell differentiation in vivo.

Advances in regenerative therapies for spinal cord injury: a biomaterials approach

Spinal cord injury results in the permanent loss of function, causing enormous personal, social and economic problems. Even though neural regeneration has been proven to be a natural mechanism, central nervous system repair mechanisms are ineffective due to the imbalance of the inhibitory and excitatory factors implicated in neuroregeneration. Therefore, there is growing research interest on discovering a novel therapeutic strategy for effective spinal cord injury repair. To this direction, cell-based delivery strategies, biomolecule delivery strategies as well as scaffold-based therapeutic strategies have been developed with a tendency to seek for the answer to a combinatorial approach of all the above. Here we review the recent advances on regenerative/neural engineering therapies for spinal cord injury, aiming at providing an insight to the most promising repair strategies, in order to facilitate future research conduction.

Chondroitin sulfate proteoglycans: Key modulators in the developing and pathologic central nervous system

Chondroitin Sulfate Proteoglycans (CSPGs) are a major component of the extracellular matrix in the central nervous system (CNS) and play critical role in the development and pathophysiology of the brain and spinal cord. Developmentally, CSPGs provide guidance cues for growth cones and contribute to the formation of neuronal boundaries in the developing CNS. Their presence in perineuronal nets plays a crucial role in the maturation of synapses and closure of critical periods by limiting synaptic plasticity. Following injury to the CNS, CSPGs are dramatically upregulated by reactive glia which form a glial scar around the lesion site. Increased level of CSPGs is a hallmark of all CNS injuries and has been shown to limit axonal plasticity, regeneration, remyelination, and conduction after injury. Additionally, CSPGs create a non-permissive milieu for cell replacement activities by limiting cell migration, survival and differentiation. Mounting evidence is currently shedding light on the potential benefits of manipulating CSPGs in combination with other therapeutic strategies to promote spinal cord repair and regeneration. Moreover, the recent discovery of multiple receptors for CSPGs provides new therapeutic targets for targeted interventions in blocking the inhibitory properties of CSPGs following injury. Here, we will provide an in depth discussion on the impact of CSPGs in normal and pathological CNS. We will also review the recent preclinical therapies that have been developed to target CSPGs in the injured CNS.

Protection and Repair After Spinal Cord Injury: Accomplishments and Future Directions

It was an honor for me to present the 2014 G. Heiner Sell Memorial Lecture at the annual American Spinal Injury Association (ASIA) meeting in San Antonio. For this purpose, I provided a comprehensive review of the scope of research targeting discovery and translational and clinical investigations into spinal cord injury (SCI) research. Indeed, these are exciting times in the area of spinal cord research and clinical initiatives. Many laboratories and clinical programs throughout the world are publishing data related to the pathophysiology of SCI and new strategies for protecting and promoting recovery in both animal models and humans. For this lecture, several topics were discussed including neuroprotective and reparative strategies, neurorehabilitation, quality of life issues, and future directions. In the area of neuroprotection, pathophysiological events that may be targeted with therapeutic strategies, including pharmacological and targeted temperature management were reviewed. For reparative approaches, the importance of both intrinsic and extrinsic mechanisms of axonal regeneration was highlighted. Various cell therapies currently being tested in preclinical and clinical arenas were reviewed as well as ongoing US Food and Drug Administration approved trials for SCI patients. Neurorehabilitation is an evolving research field with locomotive training strategies, electrical stimulation, and brain-machine interface programs targeting various types of SCI. The importance of testing combination approaches including neuroprotective, reparative, and rehabilitative strategies to maximize recovery mechanisms was therefore emphasized. Finally, quality of life issues that affect thousands of individuals living with paralysis were also presented. Future directions and specific obstacles that require attention as we continue to move the SCI field forward were discussed.

Effects of different sera conditions on olfactory ensheathing cells in vitro

Transplantation of olfactory ensheathing cells (OEC) is a promising therapy in spinal cord injury (SCI) treatment. However, the therapeutic efficacy of this method is unstable due to unknown reasons. Considering the alterations in the culture environment that occur during OEC preparation for transplantation, we hypothesize that these changes may cause variations in the curative effects of this method. In this study, we compared OEC cultured in medium containing different types and concentrations of serum. After purification and passage, the OEC were cultured for 7 days in different media containing 5%, 10%, 15% or 20% fetal bovine serum (FBS) or rat serum (RS), or the cells were cultured in FBS-containing medium first, followed by medium containing RS. In another group, the OEC were first cultured in 10% FBS for 3 days and then cultured with rat spinal cord explants with 10% RS for another 4 days. An MTT assay and P75 neurotrophin receptor immunofluorescence staining were used to examine cell viability and OEC numbers, respectively. The concentration of neurotrophin-3 (NT-3), which is secreted by OEC into the culture supernatant, was detected using the enzyme-linked immunosorbent assay (ELISA). RT-PCR was applied to investigate the NT-3 gene expression in OEC according to different groups. Compared with FBS, RS reduced OEC proliferation in relation to OEC counts (χ2 = 166.279, df = 1, p < 0.01), the optical density (OD) value in the MTT assay (χ2 = 34.730, df = 1, p < 0.01), and NT-3 concentration in the supernatant (χ2 = 242.997, df = 1, p < 0.01). OEC cultured with spinal cord explants secreted less NT-3 than OEC cultured alone (F = 9.611, df = 5.139, p < 0.01). Meanwhile, the order of application of different sera was not influential. There was statistically significant difference in NT-3 gene expression among different groups when the serum concentration was 15% (χ2 = 64.347, df = 1, p < 0.01). In conclusion, different serum conditions may be responsible for the variations in OEC proliferation and function.

Survival of neural stem cell grafts in the lesioned spinal cord is enhanced by a combination of treadmill locomotor training via insulin-like growth factor-1 signaling

Combining cell transplantation with activity-based rehabilitation is a promising therapeutic approach for spinal cord repair. The present study was designed to investigate potential interactions between the transplantation (TP) of neural stem cells (NSCs) obtained at embryonic day 14 and treadmill training (TMT) in promoting locomotor recovery and structural repair in rat contusive injury model. Combination of TMT with NSC TP at 1 week after injury synergistically improved locomotor function. We report here that combining TMT increased the survival of grafted NSCs by >3-fold and >5-fold at 3 and 9 weeks after injury, respectively. The number of surviving NSCs was significantly correlated with the extent of locomotor recovery. NSCs grafted into the injured spinal cord were under cellular stresses induced by reactive nitrogen or oxygen species, which were markedly attenuated by TMT. TMT increased the concentration of insulin-like growth factor-1 (IGF-1) in the CSF. Intrathecal infusion of neutralizing IGF-1 antibodies, but not antibodies against either BDNF or Neurotrophin-3 (NT-3), abolished the enhanced survival of NSC grafts by TMT. The combination of TP and TMT also resulted in tissue sparing, increased myelination, and restoration of serotonergic fiber innervation to the lumbar spinal cord to a larger extent than that induced by either TP or TMT alone. Therefore, we have discovered unanticipated beneficial effects of TMT in modulating the survival of grafted NSCs via IGF-1. Our study identifies a novel neurobiological basis for complementing NSC-based spinal cord repair with activity-based neurorehabilitative approaches.

Factors affecting directional migration of bone marrow mesenchymal stem cells to the injured spinal cord

Microtubule-associated protein 1B plays an important role in axon guidance and neuronal migration. In the present study, we sought to discover the mechanisms underlying microtubule-associated protein 1B mediation of axon guidance and neuronal migration. We exposed bone marrow mesenchymal stem cells to okadaic acid or N-acetyl-D-erythro-sphingosine (an inhibitor and stimulator, respectively, of protein phosphatase 2A) for 24 hours. The expression of the phosphorylated form of type I microtubule-associated protein 1B in the cells was greater after exposure to okadaic acid and lower after N-acetyl-D-erythro-sphingosine. We then injected the bone marrow mesenchymal stem cells through the ear vein into rabbit models of spinal cord contusion. The migration of bone marrow mesenchymal stem cells towards the injured spinal cord was poorer in cells exposed to okadaic acid- and N-acetyl-D-erythro-sphingosine than in non-treated bone marrow mesenchymal stem cells. Finally, we blocked phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways in rabbit bone marrow mesenchymal stem cells using the inhibitors LY294002 and U0126, respectively. LY294002 resulted in an elevated expression of phosphorylated type I microtubule-associated protein 1B, whereas U0126 caused a reduction in expression. The present data indicate that PI3K and ERK1/2 in bone marrow mesenchymal stem cells modulate the phosphorylation of microtubule-associated protein 1B via a cross-signaling network, and affect the migratory efficiency of bone marrow mesenchymal stem cells towards injured spinal cord.

Neural stem cell-conditioned medium protects neurons and promotes propriospinal neurons relay neural circuit reconnection after spinal cord injury

Human fetal neural stem cells (hNSCs) are used to treat a variety of neurological disorders involving spinal cord injury (SCI). Although their mechanism of action has been attributed to cell substitution, we examined the possibility that NSCs may have neuroprotective activities. The present article studied the action of hNSCs on protecting neurons and promoting corticospinal tract (CST) axon regeneration after SCI. hNSCs were isolated from the cortical tissue of spontaneously aborted human fetuses. The cells were removed from the NSC culture medium to acquire NSCM, thus excluding the effect of cell substitution. Continuous administration of the NSCM after the SCI resulted in extensive growth of the CST in the cervical region and more than tripled the formation of synaptic contacts between CST collaterals and propriospinal interneurons that project from the cervical level of the spinal cord to the lumbar level. NSCM reduced the number of caspase 3-positive apoptotic profiles at 7 days and protected against loss of the neurons 6 weeks after injury. NSCM promoted locomotor recovery with a five-point improvement on the BBB scale in adult rats. Thus, hNSCs help to set up a contour neural circuit via secretory factors, which may be the mechanism for their action in SCI rats. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.

Clinical outcome of autologous mononuclear cells transplantation for spinal cord injury: a systematic review and meta-analysis

BACKGROUND

Cell-based therapies can be used to treat neurological diseases and spinal cord injuries. The aim of this study was to assess the clinical outcome of bone marrow derived mononuclear cells (BM-MNCs) transplantation in patients with spinal cord injuries.

METHODS

Following a systematic review to detect clinical intervention studies, a meta-analysis was done for pooling data to estimate the outcome of BM-MNCs transplantation. The percentage of the patients with improved ASIA scale from one grade to a higher grade was defined as the main outcome. By considering the study design and outcome measurement, two reviewers independently extracted the data.

RESULTS

Eight relevant primary studies were found; seven qualified studies, with a combined total of 328 patients were assessed by meta-analysis, including 314 ASIA-A, 13 ASIA-B, 94 cervical, 227 thoracic and 60 acute injuries. The percentage of the patients' improvement was tested by meta-analysis through random and fixed models. The overall percentage of all patients' improved ASIA scale after a one- year follow-up (95% CIs) was 43 (0.27-0.59).

CONCLUSION

Data from published trials revealed that encouraging results were achieved by autologous BMMNCs for the treatment of spinal cord injury. However, the number of clinical trials included in the systematic review was too limited to reach a definite conclusion. More qualified clinical trials with standardized methods are needed to truly justify the outcome of this therapeutic modality in SCI patients.

Olfactory ensheathing cell transplantation for spinal cord injury: An 18-year bibliometric analysis based on the Web of Science

OBJECTIVE

Olfactory ensheathing cell (OEC) transplantation is a promising new approach for the treatment of spinal cord injury (SCI), and an increasing number of scientific publications are devoted to this treatment strategy. This bibliometric analysis was conducted to assess global research trends in OEC transplantation for SCI.

DATA SOURCE

All of the data in this study originate from the Web of Science maintained by the Institute for Scientific Information, USA, and includes SCI-EXPANDED, SSCI, A&HCI, CPCI-S, CPCI-SSH, BKCI-S, BKCI-SSH, CCR-EXPANDED and IC. The Institute for Scientific Information's Web of Science was searched using the keywords "olfactory ensheathing cells" or "OECs" or "olfactory ensheathing glia" or "OEG" or "olfactory ensheathing glial cells" or "OEGs" and "spinal cord injury" or "SCI" or "spinal injury" or "spinal transection" for literature published from January 1898 to May 2012.

DATA SELECTION

Original articles, reviews, proceedings papers and meeting abstracts, book chapters and editorial materials on OEC transplantation for SCI were included. Simultaneously, unpublished literature and literature for which manual information retrieval was required were excluded.

MAIN OUTCOME MEASURES

ALL SELECTED LITERATURES ADDRESSING OEC TRANSPLANTATION FOR SCI WERE EVALUATED IN THE FOLLOWING ASPECTS: publication year, document type, language, author, institution, times cited, Web of Science category, core source title, countries/territories and funding agency.

RESULTS

In the Web of Science published by the Institute for Scientific Information, the earliest literature record was in April, 1995. Four hundred and fourteen publications addressing OEC transplantation for SCI were added to the data library in the past 18 years, with an annually increasing trend. Of 415 records, 405 publications were in English. Two hundred and fifty-nine articles ranked first in the distribution of document type, followed by 141 reviews. Thirty articles and 20 reviews, cited more than 55 times by the date the publication data were downloaded by us, can be regarded as the most classical references. The journal Experimental Neurology published the most literature (32 records), followed by Glia. The United States had the most literature, followed by China. In addition, Yale University was the most productive institution in the world, while The Second Military Medical University contributed the most in China. The journal Experimental Neurology published the most OEC transplantation literature in the United States, while Neural Regeneration Research published the most in China.

CONCLUSION

This analysis provides insight into the current state and trends in OEC transplantation for SCI research. Furthermore, we anticipate that this analysis will help encourage international cooperation and teamwork on OEC transplantation for SCI to facilitate the development of more effective treatments for SCI.

Transplanted Human Induced Pluripotent Stem Cell-Derived Neural Progenitor Cells Do Not Promote Functional Recovery of Pharmacologically Immunosuppressed Mice With Contusion Spinal Cord Injury

Improved functional recovery after spinal cord injury by transplantation of induced pluripotent stem cell-derived neural stem/progenitor cells (iPSC-NPCs) has been reported. However, beneficial effects of iPSC-based therapy have so far been produced mostly using genetically immunodeficient rodents. Because of the long time required for generation and characterization of iPSCs, the use of autologous iPSCs for treating patients with acute spinal cord injury (SCI) is not feasible. Therefore, it is of utmost importance to investigate the effect of iPSC-based therapy on functional recovery after SCI using pharmacologically immunosuppressed, immunocompetent animal models. Here we studied the functional outcome following subacute transplantation of human iPSC-derived NPCs into contused mouse spinal cord when tacrolimus was used as an immunosuppressive agent. We show that human iPSC-derived NPCs transplanted into pharmacologically immunosuppressed C57BL/6J mice exhibited poor long-term survival and failed to improve functional recovery after SCI as measured by Basso Mouse Scale (BMS) for locomotion and CatWalk gait analysis when compared to vehicle-treated animals. The scarce effect of iPSC-based therapy observed in the current study may be attributable to insufficient immunosuppressive effect, provided by monotherapy with tacrolimus in combination with immunogenicity of transplanted cells and complex microenvironment of the injured spinal cord. Our results highlight the importance of extensive preclinical studies of transplanted cells before the clinical application of iPSC-based cell therapy is achieved.

Very high resolution ultrasound imaging for real-time quantitative visualization of vascular disruption after spinal cord injury

Spinal cord injury (SCI) is characterized by vascular disruption with intramedullary hemorrhage, alterations in blood-spinal cord barrier integrity, and perilesional ischemia. A safe and easily applied imaging technique to quantify evolving intraspinal vascular changes after SCI is lacking. We evaluated the utility of very high resolution ultrasound (VHRUS) imaging to assess SCI-induced vascular disruption in a clinically relevant rodent model. The spinal cords of Wistar rats were lesioned at the 11th thoracic vertebra (Th11) by a 35 g 1-minute clip compression. Three-dimensional quantification of intraspinal hemorrhage using VHRUS (at an acute 90-min and subacute 24-h time point post-SCI) was compared with lesional hemoglobin and extravasated Evans blue dye measured spectrophotometrically. The anatomy of hemorrhage was comparatively assessed using VHRUS and histology. Time-lapse videos demonstrated the evolution of parenchymal hemorrhage. VHRUS accurately depicted the structural (gray and white matter) and vascular anatomy of the spinal cord (after laminectomy) and was safely repeated in the same animal. After SCI, a hyperechoic signal extended from the lesion epicenter. Significant correlations were found between VHRUS signal and hemorrhage in the acute (r=0.88, p<0.0001) and subacute (r=0.85, p<0.0001) phases and extravasated Evans blue (a measure of vascular disruption) in the subacute phase (r=0.94, p<0.0001). Time-lapse videos demonstrated that the expanding parenchymal hemorrhage is preceded by new perilesional hemorrhagic foci. VHRUS enables real-time quantitative live anatomical imaging of acute and subacute vascular disruption after SCI in rats. This technique has important scientific and clinical translational applications.

Intrathecal Transplantation of Autologous Adherent Bone Marrow Cells Induces Functional Neurological Recovery in a Canine Model of Spinal Cord Injury

Spinal cord injury (SCI) results in demyelination of surviving axons, loss of oligodendrocytes, and impairment of motor and sensory functions. We have developed a clinical strategy of cell therapy for SCI through the use of autologous bone marrow cells for transplantation to augment remyelination and enhance neurological repair. In a preclinical large mammalian model of SCI, experimental dogs were subjected to a clipping contusion of the spinal cord. Two weeks after the injury, GFP-labeled autologous minimally manipulated adherent bone marrow cells (ABMCs) were transplanted intrathecally to investigate the safety and efficacy of autologous ABMC therapy. The effects of ABMC transplantation in dogs with SCI were determined using functional neurological scoring, and the integration of ABMCs into the injured cords was determined using histopathological and immunohistochemical investigations and electron microscopic analyses of sections from control and transplanted spinal cords. Our data demonstrate the presence of GFP-labeled cells in the injured spinal cord for up to 16 weeks after transplantation in the subacute SCI stage. GFP-labeled cells homed to the site of injury and were detected around white matter tracts and surviving axons. ABMC therapy in the canine SCI model enhanced remyelination and augmented neural regeneration, resulting in improved neurological functions. Therefore, autologous ABMC therapy appears to be a safe and promising therapy for spinal cord injuries.

Astrocyte transplantation for spinal cord injury: current status and perspective

Spinal cord injury (SCI) often causes incurable neurological dysfunction because axonal regeneration in adult spinal cord is rare. Astrocytes are gradually recognized as being necessary for the regeneration after SCI as they promote axonal growth under both physiological and pathophysiological conditions. Heterogeneous populations of astrocytes have been explored for structural and functional restoration. The results range from the early variable and modest effects of immature astrocyte transplantation to the later significant, but controversial, outcomes of glial-restricted precursor (GRP)-derived astrocyte (GDA) transplantation. However, the traditional neuron-centric view and the concerns about the inhibitory roles of astrocytes after SCI, along with the sporadic studies and the lack of a comprehensive review, have led to some confusion over the usefulness of astrocytes in SCI. It is the purpose of the review to discuss the current status of astrocyte transplantation for SCI based on a dialectical view of the context-dependent manner of astrocyte behavior and the time-associated characteristics of glial scarring. Critical issues are then analyzed to reveal the potential direction of future research.

Current status of cell-mediated regenerative therapies for human spinal cord injury

During the past decade, significant advances have been made in refinements for regenerative therapies following human spinal cord injury (SCI). Positive results have been achieved with different types of cells in various clinical studies of SCI. In this review, we summarize recently-completed clinical trials using cell-mediated regenerative therapies for human SCI, together with ongoing trials using neural stem cells. Specifically, clinical studies published in Chinese journals are included. These studies show that current transplantation therapies are relatively safe, and have provided varying degrees of neurological recovery. However, many obstacles exist, hindering the introduction of a specific clinical therapy, including complications and their causes, selection of the target population, and optimization of transplantation material. Despite these and other challenges, with the collaboration of research groups and strong support from various organizations, cell-mediated regenerative therapies will open new perspectives for SCI treatment.

Molecular imaging in stem cell therapy for spinal cord injury

Spinal cord injury (SCI) is a serious disease of the center nervous system (CNS). It is a devastating injury with sudden loss of motor, sensory, and autonomic function distal to the level of trauma and produces great personal and societal costs. Currently, there are no remarkable effective therapies for the treatment of SCI. Compared to traditional treatment methods, stem cell transplantation therapy holds potential for repair and functional plasticity after SCI. However, the mechanism of stem cell therapy for SCI remains largely unknown and obscure partly due to the lack of efficient stem cell trafficking methods. Molecular imaging technology including positron emission tomography (PET), magnetic resonance imaging (MRI), optical imaging (i.e., bioluminescence imaging (BLI)) gives the hope to complete the knowledge concerning basic stem cell biology survival, migration, differentiation, and integration in real time when transplanted into damaged spinal cord. In this paper, we mainly review the molecular imaging technology in stem cell therapy for SCI.

Stem cell therapy and curcumin synergistically enhance recovery from spinal cord injury

Acute traumatic spinal cord injury (SCI) is marked by the enhanced production of local cytokines and pro-inflammatory substances that induce gliosis and prevent reinnervation. The transplantation of stem cells is a promising treatment strategy for SCI. In order to facilitate functional recovery, we employed stem cell therapy alone or in combination with curcumin, a naturally-occurring anti-inflammatory component of turmeric (Curcuma longa), which potently inhibits NF-κB. Spinal cord contusion following laminectomy (T9–10) was performed using a weight drop apparatus (10 g over a 12.5 or 25 mm distance, representing moderate or severe SCI, respectively) in Sprague-Dawley rats. Neural stem cells (NSC) were isolated from subventricular zone (SVZ) and transplanted at the site of injury with or without curcumin treatment. Functional recovery was assessed by BBB score and body weight gain measured up to 6 weeks following SCI. At the conclusion of the study, the mass of soleus muscle was correlated with BBB score and body weight. Stem cell therapy improved recovery from moderate SCI, however, it had a limited effect on recovery after severe SCI. Curcumin stimulated NSC proliferation in vitro, and in combination with stem cell therapy, induced profound recovery from severe SCI as evidenced by improved functional locomotor recovery, increased body weight, and soleus muscle mass. These findings demonstrate that curcumin in conjunction with stem cell therapy synergistically improves recovery from severe SCI. Furthermore, our results indicate that the effect of curcumin extends beyond its known anti-inflammatory properties to the regulation of stem cell proliferation.

Safety and possible outcome assessment of autologous Schwann cell and bone marrow mesenchymal stromal cell co-transplantation for treatment of patients with chronic spinal cord injury

BACKGROUND AIMS

Cell replacement therapy has become a promising issue that has raised much hope in the regeneration of central nervous system injury. Evidence indicates that successful functional recovery in patients with spinal cord injury will not simply emphasize a single therapeutic strategy. Therefore, many recent studies have used combination strategies for spinal cord regeneration.

METHODS

We assessed the safety and feasibility of a bone marrow mesenchymal stromal cell and Schwann cell combination for the treatment of patients with chronic spinal cord injury. Eight subjects who received a complete traumatic spinal cord injury (American Spinal Injury Association [ASIA] classification A) enrolled in this study. The patients received this autologous combination of cells directly into the injury site. The mean duration of follow-up was approximately 24 months.

RESULTS

No magnetic resonance imaging evidence of neoplastic tissue overgrowth, syringomyelia or psuedomeningocele in any of the patients was seen during the study. There was no deterioration in sensory or motor function in any of the patients during the course of the study. Three patients had negligible improvement in ASIA sensory scale. No motor score improvement and no change in ASIA classification was seen. The patients had widely subjective changes in the course of the study such as urination and defecation sensation and more stability and trunk equilibrium in the sitting position.

CONCLUSIONS

There were no adverse findings at least 2 years after autologous transplantation of Schwann cell and mesenchymal stromal cell combination into the injured spinal cord. It appears that the use of this combination of cells is safe for clinical application to spinal cord regeneration.