Stem cell transplantation for spinal cord injury: a meta-analysis of treatment effectiveness and safety

Current status and future perspectives on stem cell transplantation for spinal cord injury

BACKGROUND

Previous assessments of stem cell therapy for spinal cord injuries (SCI) have encountered challenges and constraints. Current research primarily emphasizes safety in early-phase clinical trials, while systematic reviews prioritize effectiveness, often overlooking safety and translational feasibility. This situation prompts inquiries regarding the readiness for clinical adoption.

AIM

To offer an up-to-date systematic literature review of clinical trial results con cerning stem cell therapy for SCI.

METHODS

A systematic search was conducted across major medical databases [PubMed, Embase, Reference Citation Analysis (RCA), and Cochrane Library] up to October 14, 2023. The search strategy utilized relevant Medical Subject Heading (MeSH) terms and keywords related to "spinal cord", "injury", "clinical trials", "stem cells", "functional outcomes", and "adverse events". Studies included in this review consisted of randomized controlled trials and non-randomized controlled trials reporting on the use of stem cell therapies for the treatment of SCI.

RESULTS

In a comprehensive review of 66 studies on stem cell therapies for SCI, 496 papers were initially identified, with 237 chosen for full-text analysis. Among them, 236 were deemed eligible after excluding 170 for various reasons. These studies encompassed 1086 patients with varying SCI levels, with cervical injuries being the most common (42.2%). Bone marrow stem cells were the predominant stem cell type used (71.1%), with various administration methods. Follow-up durations averaged around 84.4 months. The 32.7% of patients showed functional impro vement from American spinal injury association Impairment Scale (AIS) A to B, 40.8% from AIS A to C, 5.3% from AIS A to D, and 2.1% from AIS B to C. Sensory improvements were observed in 30.9% of patients. A relatively small number of adverse events were recorded, including fever (15.1%), headaches (4.3%), muscle tension (3.1%), and dizziness (2.6%), highlighting the potential for SCI recovery with stem cell therapy.

CONCLUSION

In the realm of SCI treatment, stem cell-based therapies show promise, but clinical trials reveal potential adverse events and limitations, underscoring the need for meticulous optimization of transplantation conditions and parameters, caution against swift clinical implementation, a deeper understanding of SCI pathophysiology, and addressing ethical, tumorigenicity, immunogenicity, and immunotoxicity concerns before gradual and careful adoption in clinical practice.

Brain Plasticity in Patients with Spinal Cord Injuries: A Systematic Review

A spinal cord injury (SCI) causes changes in brain structure and brain function due to the direct effects of nerve damage, secondary mechanisms, and long-term effects of the injury, such as paralysis and neuropathic pain (NP). Recovery takes place over weeks to months, which is a time frame well beyond the duration of spinal shock and is the phase in which the spinal cord remains unstimulated below the level of injury and is associated with adaptations occurring throughout the nervous system, often referred to as neuronal plasticity. Such changes occur at different anatomical sites and also at different physiological and molecular biological levels. This review aims to investigate brain plasticity in patients with SCIs and its influence on the rehabilitation process. Studies were identified from an online search of the PubMed, Web of Science, and Scopus databases. Studies published between 2013 and 2023 were selected. This review has been registered on OSF under (n) 9QP45. We found that neuroplasticity can affect the sensory-motor network, and different protocols or rehabilitation interventions can activate this process in different ways. Exercise rehabilitation training in humans with SCIs can elicit white matter plasticity in the form of increased myelin water content. This review has demonstrated that SCI patients may experience plastic changes either spontaneously or as a result of specific neurorehabilitation training, which may lead to positive outcomes in functional recovery. Clinical and experimental evidence convincingly displays that plasticity occurs in the adult CNS through a variety of events following traumatic or non-traumatic SCI. Furthermore, efficacy-based, pharmacological, and genetic approaches, alone or in combination, are increasingly effective in promoting plasticity.

Current advances in stem cell therapy in the treatment of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory disease related to the central nervous system (CNS) with a significant global burden. In this illness, the immune system plays an essential role in its pathophysiology and progression. The currently available treatments are not recognized as curable options and, at best, might slow the progression of MS injuries to the CNS. However, stem cell treatment has provided a new avenue for treating MS. Stem cells may enhance CNS healing and regulate immunological responses. Likewise, stem cells can come from various sources, including adipose, neuronal, bone marrow, and embryonic tissues. Choosing the optimal cell source for stem cell therapy is still a difficult verdict. A type of stem cell known as mesenchymal stem cells (MSCs) is obtainable from different sources and has a strong immunomodulatory impact on the immune system. According to mounting data, the umbilical cord and adipose tissue may serve as appropriate sources for the isolation of MSCs. Human amniotic epithelial cells (hAECs), as novel stem cell sources with immune-regulatory effects, regenerative properties, and decreased antigenicity, can also be thought of as a new upcoming contender for MS treatment. Overall, the administration of stem cells in different sets of animal and clinical trials has shown immunomodulatory and neuroprotective results. Therefore, this review aims to discuss the different types of stem cells by focusing on MSCs and their mechanisms, which can be used to treat and improve the outcomes of MS disease.

Stem Cell Therapy in Spinal Cord Injury-Induced Neurogenic Lower Urinary Tract Dysfunction

Spinal cord injury (SCI) is a devastating condition that enormously affects an individual's health and quality of life. Neurogenic lower urinary tract dysfunction (NLUTD) is one of the most important sequelae induced by SCI, causing complications including urinary tract infection, renal function deterioration, urinary incontinence, and voiding dysfunction. Current therapeutic methods for SCI-induced NLUTD mainly target on the urinary bladder, but the outcomes are still far from satisfactory. Stem cell therapy has gained increasing attention for years for its ability to rescue the injured spinal cord directly. Stem cell differentiation and their paracrine effects, including exosomes, are the proposed mechanisms to enhance the recovery from SCI. Several animal studies have demonstrated improvement in bladder function using mesenchymal stem cells (MSCs) and neural stem cells (NSCs). Human clinical trials also provide promising results in urodynamic parameters after MSC therapy. However, there is still uncertainty about the ideal treatment window and application protocol for stem cell therapy. Besides, data on the therapeutic effects regarding NSCs and stem cell-derived exosomes in SCI-related NLUTD are scarce. Therefore, there is a pressing need for further well-designed human clinical trials to translate the stem cell therapy into a formal therapeutic option for SCI-induced NLUTD.

Behavioral context improves optogenetic stimulation of transplanted dopaminergic cells in unilateral 6-OHDA rats

Stem cell therapy has long been a popular method of treatment for Parkinson's disease currently being researched in both preclinical and clinical settings. While early clinical results are based upon fetal tissue transplants rather than stem cell transplants, the lack of successful integration in some patients and gradual loss of effect in others suggests a more robust protocol is needed. We propose a two-front approach, one where transplants are directly stimulated in coordination with host activity elicited by behavioral tasks, which we refer to as behavioral context. After a pilot with unilateral 6-OHDA rats transplanted with dopaminergic cells differentiated from mesenchymal stem cells that were optogenetically stimulated during a swim task, we discovered that early stimulation predicted lasting reduction of motor deficits, even in the absence of later stimulation. This led to a follow-up with n = 21 rats split into three groups: one stimulated while performing a swim task (Stim-Swim; St-Sw), one not stimulated while swimming (NoStim-Swim; NSt-Sw), and one stimulated while stationary in a bowl (Stim-NoSwim; St-NSw). After initial stimulation (or lack thereof), all rats were retested two and seven days later with the swim task in the absence of stimulation. The St-Sw group gradually achieved and maintained symmetrical limb use, whereas the NSt-Sw group showed persistent asymmetry and the St-NSw group showed mixed results. This supports the notion that stem cell therapy should integrate targeted stimulation of the transplant with behavioral stimulation of the host tissue to encourage proper functional integration of the graft.

Motor functional recovery efficacy of scaffolds with bone marrow stem cells in rat spinal cord injury: a Bayesian network meta-analysis

STUDY DESIGN

A Bayesian network meta-analysis.

OBJECTIVE

Spinal cord injury (SCI) can profoundly influence human health and has been linked to lifelong disability. More high-level evidence-based medical research is expected to evaluate the value of stem cells and biomaterial scaffold material therapy for SCI.

METHODS

We performed a comprehensive search of Web of Science, Cochrane databases, Embase, and PubMed databases. 18 randomized controlled trials including both scaffolds and BMSCs were included. We performed a Bayesian network meta-analysis to compare the motor functional recovery efficacy of different scaffolds with BMSCs in rat SCI.

RESULTS

In our Bayesian network meta-analysis, the motor functional recovery was found to benefit from scaffolds, BMSCs, and BMSCs combined with scaffolds, but the scaffold and BMSC groups had similar motor functional recovery efficacy, and the BMSCs combined with scaffolds group appeared to show better efficacy than BMSCs and scaffolds alone. Subgroup analysis showed that BMSCs+fibrin, BMSCs+ASC, BMSCs+gelatine, and BMSCs+collagen were the best four treatments for SCI in rat models.

CONCLUSIONS

These Bayesian network meta-analysis findings strongly indicated that BMSCs combined with scaffolds is more effective to improve motor functional recovery than BMSCs and scaffolds alone. The fibrin, gelatine, ASC, and collagen may be favourable scaffolds for the injured spinal cord and that scaffolds with BMSCs could be a promising option in regeneration therapy for patients with SCI.

Research progress of hydrogels as delivery systems and scaffolds in the treatment of secondary spinal cord injury

Secondary spinal cord injury (SSCI) is the second stage of spinal cord injury (SCI) and involves vasculature derangement, immune response, inflammatory response, and glial scar formation. Bioactive additives, such as drugs and cells, have been widely used to inhibit the progression of secondary spinal cord injury. However, the delivery and long-term retention of these additives remain a problem to be solved. In recent years, hydrogels have attracted much attention as a popular delivery system for loading cells and drugs for secondary spinal cord injury therapy. After implantation into the site of spinal cord injury, hydrogels can deliver bioactive additives in situ and induce the unidirectional growth of nerve cells as scaffolds. In addition, physical and chemical methods can endow hydrogels with new functions. In this review, we summarize the current state of various hydrogel delivery systems for secondary spinal cord injury treatment. Moreover, functional modifications of these hydrogels for better therapeutic effects are also discussed to provide a comprehensive insight into the application of hydrogels in the treatment of secondary spinal cord injury.

Heterogeneous pHPMA hydrogel promotes neuronal differentiation of bone marrow derived stromal cellsin vitroandin vivo

Synthetic hydrogels composed of polymer pore frames are commonly used in medicine, from pharmacologically targeted drug delivery to the creation of bioengineering constructions used in implantation surgery. Among various possible materials, the most common are poly-[N(2-hydroxypropyl)methacrylamide] (pHPMA) derivatives. One of the pHPMA derivatives is biocompatible hydrogel, NeuroGel. Upon contact with nervous tissue, the NeuroGel's structure can support the chemical and physiological conditions of the tissue necessary for the growth of native cells. Owing to the different pore diameters in the hydrogel, not only macromolecules, but also cells can migrate. This study evaluated the differentiation of bone marrow stromal cells (BMSCs) into neurons, as well as the effectiveness of using this biofabricated system in spinal cord injuryin vivo. The hydrogel was populated with BMSCs by injection or rehydration. After cultivation, these fragments (hydrogel + BMSCs) were implanted into the injured rat spinal cord. Fragments were immunostained before implantation and seven months after implantation. During cultivation with the hydrogel, both variants (injection/rehydration) of the BMSCs culture retained their viability and demonstrated a significant number of Ki-67-positive cells, indicating the preservation of their proliferative activity. In hydrogel fragments, BMSCs also maintained their viability during the period of cocultivation and were Ki-67-positive, but in significantly fewer numbers than in the cell culture. In addition, in fragments of hydrogel with grafted BMSCs, both by the injection or rehydration versions, we observed a significant number up to 57%-63.5% of NeuN-positive cells. These results suggest that the heterogeneous pHPMA hydrogel promotes neuronal differentiation of bone marrow-derived stromal cells. Furthermore, these data demonstrate the possible use of NeuroGel implants with grafted BMSCs for implantation into damaged areas of the spinal cord, with subsequent nerve fiber germination, nerve cell regeneration, and damaged segment restoration.

Molecular Mechanisms and Clinical Application of Multipotent Stem Cells for Spinal Cord Injury

Spinal Cord Injury (SCI) is a common neurological disorder with devastating psychical and psychosocial sequelae. The majority of patients after SCI suffer from permanent disability caused by motor dysfunction, impaired sensation, neuropathic pain, spasticity as well as urinary complications, and a small number of patients experience a complete recovery. Current standard treatment modalities of the SCI aim to prevent secondary injury and provide limited recovery of lost neurological functions. Stem Cell Therapy (SCT) represents an emerging treatment approach using the differentiation, paracrine, and self-renewal capabilities of stem cells to regenerate the injured spinal cord. To date, multipotent stem cells including mesenchymal stem cells (MSCs), neural stem cells (NSCs), and hematopoietic stem cells (HSCs) represent the most investigated types of stem cells for the treatment of SCI in preclinical and clinical studies. The microenvironment of SCI has a significant impact on the survival, proliferation, and differentiation of transplanted stem cells. Therefore, a deep understanding of the pathophysiology of SCI and molecular mechanisms through which stem cells act may help improve the treatment efficacy of SCT and find new therapeutic approaches such as stem-cell-derived exosomes, gene-modified stem cells, scaffolds, and nanomaterials. In this literature review, the pathogenesis of SCI and molecular mechanisms of action of multipotent stem cells including MSCs, NSCs, and HSCs are comprehensively described. Moreover, the clinical efficacy of multipotent stem cells in SCI treatment, an optimal protocol of stem cell administration, and recent therapeutic approaches based on or combined with SCT are also discussed.

Clinical translation of stem cell therapy for spinal cord injury still premature: results from a single-arm meta-analysis based on 62 clinical trials

BACKGROUND

How much scientific evidence is there to show that stem cell therapy is sufficient in preclinical and clinical studies of spinal cord injury before it is translated into clinical practice? This is a complicated problem. A single, small-sample clinical trial is difficult to answer, and accurate insights into this question can only be given by systematically evaluating all the existing evidence.

METHODS

The PubMed, Ovid-Embase, Web of Science, and Cochrane databases were searched from inception to February 10, 2022. Two independent reviewers performed the literature search, identified and screened the studies, and performed a quality assessment and data extraction.

RESULTS

In total, 62 studies involving 2439 patients were included in the analysis. Of these, 42 were single-arm studies, and 20 were controlled studies. The meta-analysis showed that stem cells improved the ASIA impairment scale score by at least one grade in 48.9% [40.8%, 56.9%] of patients with spinal cord injury. Moreover, the rate of improvement in urinary and gastrointestinal system function was 42.1% [27.6%, 57.2%] and 52.0% [23.6%, 79.8%], respectively. However, 28 types of adverse effects were observed to occur due to stem cells and transplantation procedures. Of these, neuropathic pain, abnormal feeling, muscle spasms, vomiting, and urinary tract infection were the most common, with an incidence of > 20%. While no serious adverse effects such as tumorigenesis were reported, this could be due to the insufficient follow-up period.

CONCLUSIONS

Overall, the results demonstrated that although the efficacy of stem cell therapy is encouraging, the subsequent adverse effects remain concerning. In addition, the clinical trials had problems such as small sample sizes, poor design, and lack of prospective registration, control, and blinding. Therefore, the current evidence is not sufficiently strong to support the clinical translation of stem cell therapy for spinal cord injury, and several problems remain. Additional well-designed animal experiments and high-quality clinical studies are warranted to address these issues.

A systematic review of large animal and human studies of stem cell therapeutics for acute adult traumatic spinal cord injury

Background: Traumatic spinal cord injury (TSCI) is a devastating condition and the search for a cure remains one of the most tenacious healthcare challenges to date. Current therapies are limited in their efficacy to restore full neurological function – resulting in lifelong disability and loss of autonomy. Whilst there remains a necessity to refine therapeutic protocols, stem cell (SC) studies have shown promise in the mending and re-establishment of the spinal cord neuroanatomy. Objectives: We conducted a systematic review of functional outcomes in stem cell therapeutics over the last three decades in large animals and humans. Methods: Medline, Embase, Cochrane and SCOPUS databases were searched for potentially pertinent articles from 1990 to 2020. Studies published in English were included if the stem cells were directly injected into the intraspinal, epidural or intrathecal compartments within two weeks of a traumatic mechanism of injury, including acute intervertebral disc prolapse. The participants were either large animals – defined as canine, porcine or non-human primate in-vivo models – or human patients. Results: Nine studies were included in this review. Statistically significant improvements in motor function and deep pain perception were seen at 8 weeks to 6 months post-SC injection compared to controls. Limitations: Functional outcomes are variably measured across studies. Almost all studies used experimentally induced trauma, which may not accurately represent the complexity of human spinal cord injury. Due to the exclusion criteria, there were no non-human primate studies included, yet these animal models are considered a closer anatomical match to humans than other large mammals. No human studies were included. Conclusions and Implications: Autologous and allogeneic stem cells have been trialled for the reconstitution of damaged and lost cells, remyelination of axons and remodelling of the pathophysiological microenvironment within the injured spinal cord, with some promising outcome data. This may translate to more successful future Phase I/II human clinical trials into the use of stem cells after TSCI in adults.

Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges

Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.

Regenerative Rehabilitation and Stem Cell Therapy Targeting Chronic Spinal Cord Injury: A Review of Preclinical Studies

Stem cell medicine has led to functional recovery in the acute-to-subacute phase of spinal cord injury (SCI), but not yet in the chronic phase, during which various molecular mechanisms drastically remodel the tissue and render it treatment-resistant. Researchers are attempting to identify effective combinatorial treatments that can overcome the refractory state of the chronically injured spinal cord. Regenerative rehabilitation, combinatorial treatment with regenerative medicine that aims to elicit synergistic effects, is being developed. Rehabilitation upon SCI in preclinical studies has recently attracted more attention because it is safe, induces neuronal plasticity involving transplanted stem cells and sensorimotor circuits, and is routinely implemented in human clinics. However, regenerative rehabilitation has not been extensively reviewed, and only a few reviews have focused on the use of physical medicine modalities for rehabilitative purposes, which might be more important in the chronic phase. Here, we summarize regenerative rehabilitation studies according to the effector, site, and mechanism. Specifically, we describe effects on transplanted cells, microstructures at and distant from the lesion, and molecular changes. To establish a treatment regimen that induces robust functional recovery upon chronic SCI, further investigations are required of combinatorial treatments incorporating stem cell therapy, regenerative rehabilitation, and medication.

A comparative study of different stem cells transplantation for spinal cord injury: a systematic review and network meta-analysis

OBJECTIVE

This study aimed to evaluate the efficacy and safety of different stem cell types for spinal cord injury (SCI) therapy and find out the superior treatment for SCI.

METHODS

A systematic literature search was performed using PubMed, Embase, the Cochrane Library, Web of Science, VIP, CNKI, and Wan Fang from database initiation to January 30, 2021. A Bayesian network meta-analysis was performed using ADDIS software. The PROSPERO registration number was CRD42020129635.

RESULTS

Twelve studies with 642 patients were enrolled in this study. Network meta-analysis revealed that bone mesenchymal stem cells combined with rehabilitation training (BMSCs + R) were significantly more effective than rehabilitation training alone (R) in improving American Spinal Injury Association (ASIA) impairment scale (AIS)-grading improvement rate (OR=94.25, 95% CI: 6.71 to 9321.95), ASIA motor score (WMD=6.67, 95% CI: 0.83 to 12.73), ASIA Sensory Functional score (WMD=12.41, 95%CI: 3.42 to 21.72), and Barthel Index (BI) score (WMD=7.24, 95% CI: 0.21 to 14.30). However, no statistically significant differences were observed between marrow mononuclear cells combined with rehabilitation training (MNCs + R), umbilical cord-derived mesenchymal stem cells combined with rehabilitation training (UCMSCs + R), or UCMSCs alone and R on all indicators. In terms of safety, there were no serious and permanent adverse effects after transplantation of BMSCs, MNCs, or UCMSCs.

CONCLUSION

BMSCs + R may be superior to the other stem cell treatments for SCI in improving AIS grading, ASIA motor score, ASIA Sensory Functional score, and BI score. The therapeutic effects of UCMSCs and MNCs remain to be confirmed.

Clinical application of stem cell therapy in neurogenic bladder: a systematic review and meta-analysis

INTRODUCTION AND HYPOTHESIS

This review aims to investigate the effect of stem cell (SC) therapy on the management of neurogenic bladder (NGB) in four neurological diseases, including spinal cord injury (SCI), Parkinson's disease (PD), multiple sclerosis (MS), and stroke, in the clinical setting.

METHODS

An electronic database search was conducted in the Cochrane Library, EMBASE, Proquest, Clinicaltrial.gov , WHO, Google Scholar, MEDLINE via PubMed, Ovid, Web of Science, Scopus, ongoing trial registers, and conference proceedings in June 2019 and updated by hand searching on 1 February 2021. All randomized controlled trials (RCTs), quasi RCTs, phase I/II clinical trials, case-control, retrospective cohorts, and comprehensive case series that evaluated the regenerative potential of SCs on the management of NGB were included. Cochrane appraisal risk of bias checklist and the standardized critical appraisal instrument from the JBI Meta-Analysis of Statistics, Assessment, and Review Instrument (JBI-MAStARI) were used to appraise the studies.

RESULTS

Twenty-six studies among 1282 relevant publications met our inclusion criteria. Only SC therapy was applied for SCI or MS patients. Phase I/II clinical trials (without control arm) were the most conducted studies, and only four were RCTs. Four studies with 153 participants were included in the meta-analysis. The main route of transplantation was via lumbar puncture. There were no serious adverse events. Only nine studies in SCI and one in MS have used urodynamics, and the others have reported improvement based on patient satisfaction. SC therapy did not significantly improve residual urine volume, detrusor pressure, and maximum bladder capacity. Also, the quality of these publications was low or unclear.

CONCLUSION

Although most clinical trials provide evidence of the safety and effectiveness of MSCs on the management of NGB, the meta-analysis results did not show a significant improvement; however, the interpretation of study results is difficult because of the lack of placebo controls.

Efficacy of adipose tissue-derived stem cells in locomotion recovery after spinal cord injury: a systematic review and meta-analysis on animal studies

BACKGROUND

Considerable disparities exist on the use of adipose tissue-derived stem cells (ADSCs) for treatment of spinal cord injury (SCI). Hence, the current systematic review aimed to investigate the efficacy of ADSCs in locomotion recovery following SCI in animal models.

METHODS

A search was conducted in electronic databases of MEDLINE, Embase, Scopus, and Web of Science until the end of July 2019. Reference and citation tracking and searching Google and Google Scholar search engines were performed to achieve more studies. Animal studies conducted on rats having SCI which were treated with ADSCs were included in the study. Exclusion criteria were lacking a non-treated control group, not evaluating locomotion, non-rat studies, not reporting the number of transplanted cells, not reporting isolation and preparation methods of stem cells, review articles, combination therapy, use of genetically modified ADSCs, use of induced pluripotent ADSCs, and human trials. Risk of bias was assessed using Hasannejad et al.'s proposed method for quality control of SCI-animal studies. Data were analyzed in STATA 14.0 software, and based on a random effect model, pooled standardized mean difference with a 95% confidence interval was presented.

RESULTS

Of 588 non-duplicated papers, data from 18 articles were included. Overall risk of bias was high risk in 8 studies, some concern in 9 studies and low risk in 1 study. Current evidence demonstrated that ADSCs transplantation could improve locomotion following SCI (standardized mean difference = 1.71; 95%CI 1.29-2.13; p < 0.0001). A considerable heterogeneity was observed between the studies (I² = 72.0%; p < 0.0001). Subgroup analysis and meta-regression revealed that most of the factors like injury model, the severity of SCI, treatment phase, injury location, and number of transplanted cells did not have a significant effect on the efficacy of ADSCs in improving locomotion following SCI (p_{for odds ratios} > 0.05).

CONCLUSION

We conclude that any number of ADSCs by any prescription routes can improve locomotion recovery in an SCI animal model, at any phase of SCI, with any severity. Given the remarkable bias about blinding, clinical translation of the present results is tough, because in addition to the complexity of the nervous system and the involvement of far more complex motor circuits in the human, blinding compliance and motor outcome assessment tests in animal studies and clinical trials are significantly different.

Biomaterials reinforced MSCs transplantation for spinal cord injury repair

Due to the complex pathophysiological mechanism, spinal cord injury (SCI) has become one of the most intractable central nervous system (CNS) diseases to therapy. Stem cell transplantation, mesenchymal stem cells (MSCs) particularly, appeals to more and more attention along with the encouraging therapeutic results for the functional regeneration of SCI. However, traditional cell transplantation strategies have some limitations, including the unsatisfying survival rate of MSCs and their random diffusion from the injection site to ambient tissues. The application of biomaterials in tissue engineering provides a new horizon. Biomaterials can not only confine MSCs in the injured lesions with higher cell viability, but also promote their therapeutic efficacy. This review summarizes the strategies and advantages of biomaterials reinforced MSCs transplantation to treat SCI in recent years, which are clarified in the light of various therapeutic effects in pathophysiological aspects of SCI.

Combined treatment with enteric neural stem cells and chondroitinase ABC reduces spinal cord lesion pathology

BACKGROUND

Spinal cord injury (SCI) presents a significant challenge for the field of neurotherapeutics. Stem cells have shown promise in replenishing the cells lost to the injury process, but the release of axon growth-inhibitory molecules such as chondroitin sulfate proteoglycans (CSPGs) by activated cells within the injury site hinders the integration of transplanted cells. We hypothesised that simultaneous application of enteric neural stem cells (ENSCs) isolated from the gastrointestinal tract, with a lentivirus (LV) containing the enzyme chondroitinase ABC (ChABC), would enhance the regenerative potential of ENSCs after transplantation into the injured spinal cord.

METHODS

ENSCs were harvested from the GI tract of p7 rats, expanded in vitro and characterised. Adult rats bearing a contusion injury were randomly assigned to one of four groups: no treatment, LV-ChABC injection only, ENSC transplantation only or ENSC transplantation+LV-ChABC injection. After 16 weeks, rats were sacrificed and the harvested spinal cords examined for evidence of repair.

RESULTS

ENSC cultures contained a variety of neuronal subtypes suitable for replenishing cells lost through SCI. Following injury, transplanted ENSC-derived cells survived and ChABC successfully degraded CSPGs. We observed significant reductions in the injured tissue and cavity area, with the greatest improvements seen in the combined treatment group. ENSC-derived cells extended projections across the injury site into both the rostral and caudal host spinal cord, and ENSC transplantation significantly increased the number of cells extending axons across the injury site. Furthermore, the combined treatment resulted in a modest, but significant functional improvement by week 16, and we found no evidence of the spread of transplanted cells to ectopic locations or formation of tumours.

CONCLUSIONS

Regenerative effects of a combined treatment with ENSCs and ChABC surpassed either treatment alone, highlighting the importance of further research into combinatorial therapies for SCI. Our work provides evidence that stem cells taken from the adult gastrointestinal tract, an easily accessible source for autologous transplantation, could be strongly considered for the repair of central nervous system disorders.

Effects of Edaravone on Functional Recovery of a Rat Model with Spinal Cord Injury Through Induced Differentiation of Bone Marrow Mesenchymal Stem Cells into Neuron-Like Cells

Edaravone can induce differentiation of bone marrow mesenchymal stem cells (BMSCs) into neuron-like cells and replace lost cells by transplanting neuron-like cells to repair spinal cord injury (SCI). In this study, BMSCs were derived from the bone marrow of male Wistar rats (4 weeks old) through density gradient centrifugation (1.073 g/mL), and the cell purity of BMSCs was up to 95%. The combined injection of basic fibroblast growth factor and edaravone was conducted to differentiate BMSCs into neuron-like cells. In this study, 120 male Wistar rats were used to establish the model of semitransverse SCI; on the seventh day, neuron-like cells were labeled by BrdU and then injected into the epicenter of the injury of rats. On the 14th day after cell transplantation, the biotin dextran amine (BDA) fluorescent agent was used to track the repair of nerve damage. At 7, 14, 21, and 30 days after SCI, the Basso, Beattie, and Bresnahan (BBB) locomotor scale method was used to measure the functional recovery of hind limbs in rats. Additionally, hematoxylin and eosin (H&E) staining, Nissl staining, immunohistochemistry, transmission electron microscopy (TEM), Western blotting, and Real-time quantitative reverse transcripion PCR (qRT-PCR) were used to observe the regeneration of nerve cells. In the edaravone+BMSC group, behavioral analysis of locomotor function showed that functional recovery was significantly enhanced after transplantation of the cells, BrdU-positive cells could be observed scattered in the injured area and extended to both the head and tail, and the BDA tracer shows that the edaravone+BMSC group emits more fluorescent signals. Additionally, H&E staining, Nissl staining, and immunohistochemistry revealed that the space of spinal cord tissue was attenuated and the neurons were increased. Western blotting and qRT-PCR showed that the expression levels of neuron-specific enolase (NSE), Nestin, and neurofilament 200 (NF) were increased, while the expression of glial fibrillary acidic protein (GFAP) was decreased. TEM showed that cytoplasmic edema was reduced, mitochondrial vacuoles were attenuated, and nuclear chromatin concentration was declined after transplantation of neuron-like cells. Moreover, with the extension of time of edaravone+BMSC transplantation, the structures of mitochondria and endoplasmic reticulum tended to be normal. In summary, the induced differentiation of BMSC transplantation can significantly promote the functional repair of SCI.

HUCMSCs transplantation combined with ultrashort wave therapy attenuates neuroinflammation in spinal cord injury through NUR77/ NF-κB pathway

AIMS

Spinal cord injury (SCI) is a major cause of long-term physical impairment. Currently, treatment for SCI is limited to supportive measures, which can lead to permanent disability, representing a serious social burden. The present study aimed to evaluate the inflammatory microenvironment effects of human umbilical cord mesenchymal stem cells (HUCMSCs)+ Ultrashort Wave (USW) therapy on SCI and reveal possible mechanisms.

MAIN METHODS

Low-dose USW was treated one day after SCI, and HUCMSCs suspension was transferred to the lesion using a micro-syringe 7 days after SCI. The functional effects of HUCMSCs and USW, separately and combinedly, were measured, together with the infiltration of CD3⁺ cells, formation of A1 astrocytes and activation of NUR77/ NF-κB pathway.

KEY FINDINGS

Our results showed that HUCMSCs+USW therapy improved motor function of SCI rat, together with decreased infiltration of CD3⁺ T cells, and decreased induction of microglia and A1 astrocytes. And also USW treatment played a very important role on decreasing the infiltration of CD3⁺ T cells and IBA-1⁺ cells. Reduced production of pro-inflammatory cytokines IL-1β and IL-6 was also observed in rats receiving HUCMSCs+USW therapy, medicated by NUR77/NF-κB pathway.

SIGNIFICANCE

These findings indicated that HUCMSCs+USW therapy could attenuate inflammatory microenvironment through NUR77/NF-κB signaling pathway, which might contribute to its better outcome.

[Human umbilical cord mesenchymal stem cells differentiate into neuron-like cells after induction with B27-supplemented serum-free medium]

OBJECTIVE

To evaluate the capacity and efficiency of human umbilical cord mesenchymal stem cells (HUCMSCs) to differentiate into neuron- like cells after induction with B27- supplemented serum- free medium.

METHODS

HUCMSCs at passage 4 were cultured for 14 days with serum-containing medium (SCM) (group A), SCM supplemented with 20 ng/mL nerve growth factor (NGF) and 10 ng/mL basic fibroblast growth factor (bFGF) (group B), serum-free medium (SFM) (group C), or SFM supplemented with 20 ng/mL NGF and 10 ng/mL bFGF. The culture medium were changed every 3 days and the growth of the neurospheres was observed using an inverted microscope. The cell markers were analyzed with flow cytometry and the expressions of nestin, neuron- specific enolase (NSE), neurofilament heavy polypeptide (NEFH), and glial fibrillary acidic protein (GFAP) were quantified by quantitative real-time PCR (qRT-PCR) and Western blotting.

RESULTS

Before induction, HUCMSCs expressed abundant mesenchymal stem cell surface markers including CD29 (99.5%), CD44 (49.6%) and CD105 (77.7%). Neuron-like cells were observed in the cultures on days 7, 10, and 14, and the cell differentiation was the best in group D, followed by groups C, B and A. In all the 4 groups, the cellular expressions of nestin and GFAP gradually lowered while those of NEFH and NSE increased progressively. The expressions of GFAP, NEFH, nestin and NSE were significantly different between group A and the other 3 groups (P < 0.001 or 0.05).

CONCLUSIONS

B27-supplemented SFM effectively induces the differentiation of HUCMSCs into neuron- like cells, and the supplementation with cytokines (NGF and bFGF) strongly promotes the cell differentiation.

Generation of Neural Progenitor Cells From Canine Induced Pluripotent Stem Cells and Preliminary Safety Test in Dogs With Spontaneous Spinal Cord Injuries

Advances in stem cell technology, including the use of induced pluripotent stem cells (iPSC) to produce neurons and glial cells, offer new hope for patients with neurological disease and injuries. Pet dogs with spinal cord injuries provide an important spontaneous animal model for evaluating new approaches to stem cell therapy. Therefore, studies were conducted to identify optimal conditions for generating neural progenitor cells (NPC) from canine induced pluripotent stem cells (iPSC) for preliminary evaluation in animals with spinal cord injury. We found that canine NPC could be induced to differentiate into mature neural cells, including glia and neurons. In addition, canine NPC did not form teratomas when injected in NOD/SCID mice. In a pilot study, two dogs with chronic spinal cord injury underwent fluoroscopically guided intrathecal injections of canine NPC. In follow-up MRI evaluations, tumor formation was not observed at the injection sites. However, none of the animals experienced meaningful clinical or electrophysiological improvement following NPC injections. These studies provide evidence that canine iPSC can be used to generate NPC for evaluation in cellular therapy of chronic spinal cord injury in the dog spontaneous injury model. Further refinements in the cell implantation procedure are likely required to enhance stem cell treatment efficacy.

Efficacy and safety of neural stem cell therapy for spinal cord injury: A systematic literature review

AIMS

To summarize the evidence on the efficacy and safety of neural stem cell therapy (NSCT) for the treatment of spinal cord injury (SCI).

METHODS

A systematic literature review of Medline®, EMBASE® and Cochrane library was performed to identify studies reporting efficacy and safety of NSCT in SCI. Articles were included if they reported efficacy and safety data of SCI patients who received NSCT.

RESULTS

Overall, four studies of the 277 records met all the study eligibility criteria. Over the 1-year follow-up period, motor scores were significantly higher among patients who received NSCT compared with those who did not (American Spinal Injury Association [ASIA] motor scores (mean±standard deviation [SD]): 7.9±1.2 versus 3.9±0.6; upper extremity motor score: 7.8±2.1 versus 3.9±0.6, both P<0.05). Sensory scores (pinprick score: 4.8±1.3 versus 2.9±0.6; P=0.5; light touch score: 6.9±3.1 versus 2.3±0.5, P=0.3), ASIA impairment scale (26% versus 7%) or pain score (baseline: 2.4±0.6; 1-year: 3.4±0.4) were comparable in both NSCT and non-NSCT cohorts. Over the 1-year follow-up period, the graded redefined assessment of strength, sensibility, and prehension and international standards for neurological classification of SCI scores showed a mean improvement of 14.8 and 17.8 points respectively. Overall, treatment with NSCT showed favorable safety and tolerability profile.

CONCLUSIONS

Due to the limited and poor-quality evidence, it is too early to make robust conclusions on the efficacy of NSCT in the treatment of SCI. However, based on the included studies, NSCT seems to be a potential option worth exploring among patients with SCI. Nonetheless, prospective, randomized trials in larger cohorts are needed to validate the efficacy and safety of NSCT in the treatment of SCI.

Therapeutic repair for spinal cord injury: combinatory approaches to address a multifaceted problem

The recent years saw the advent of promising preclinical strategies that combat the devastating effects of a spinal cord injury (SCI) that are progressing towards clinical trials. However, individually, these treatments produce only modest levels of recovery in animal models of SCI that could hamper their implementation into therapeutic strategies in spinal cord injured humans. Combinational strategies have demonstrated greater beneficial outcomes than their individual components alone by addressing multiple aspects of SCI pathology. Clinical trial designs in the future will eventually also need to align with this notion. The scenario will become increasingly complex as this happens and conversations between basic researchers and clinicians are required to ensure accurate study designs and functional readouts.

Autologous Transplantation of Adipose-Derived Stem Cells to Treat Acute Spinal Cord Injury: Evaluation of Clinical Signs, Mental Signs, and Quality of Life

BACKGROUD

Spinal cord injury (SCI) is damage that can cause a temporary or permanent change in spinal cord functions.

AIM:

This work evaluates clinical signs, mental signs, and quality of life (QoL) after autologous adipose-derived stem cells (ADSCs) transplantation to treat acute spinal cord injury (SCI).

METHODS:

In this study, 47 SCI patients were recruited and divided into two groups: intervention and control. ADSCs were isolated and cultured under the cell culture quality control procedure. All patients in both groups underwent neurosurgery with or without ADSC transplantation. The recovery regarding neurological muscle, QoL, neurogenic bladder, and mental improvement was assessed after transplantation.

RESULTS:

All patients had improved in terms of motor function, bladder function, and daily living. No patients reported any side effect. MRI imaging showed significant changes in the lesion length of the spinal canal and the thickening of the spinal cord. Mental improvement was highest at six months after transplantation and lowest at one month after transplantation. The proportion of patients whose quality of life improved after treatment was 100%, while 80% of patients were satisfied with treatment outcomes.

CONCLUSIONS

Thus, our data suggested that ADSCs transplantation was safe and effective for the treatment of SCI patients. Neurological muscle and neurogenic bladder were improved significantly after transplantation.

Can Paraplegia by Disruption of the Spinal Cord Tissue Be Reversed? The Signs of a New Perspective

Central nervous system (CNS) trauma is often related to tissue loss, leading to partial or complete disruption of spinal cord function due to neuronal death. Although generally irreversible, traditional therapeutic efforts, such as physical therapy exercises, are generally recommended, but with a poor or reduced improvement of the microenvironment, which in turn stimulates neuroplasticity and neuroregeneration. Mesenchymal stem cells (MSCs) have paracrine, immunomodulatory, and anti-inflammatory effects. Here we use stem cells to see if they can promote not only physical but also the functional regeneration of neuronal tissue in dogs with CNS traumas. Two dogs, one with chronic spinal cord injury and one with subacute spinal cord injury, underwent infusion of autologous MSCs in association with physiotherapy. The two treatments in combination were able to partially or completely recover the dog's walking movement again. The treatment of MSCs in association with physical therapy improved the microenvironment, which could be evidence of a paradigm shift that the CNS is not capable of functional regeneration after aggressive traumas. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1812-1820, 2020. © 2019 American Association for Anatomy.

The Effect of Wharton Jelly-Derived Mesenchymal Stromal Cells and Their Conditioned Media in the Treatment of a Rat Spinal Cord Injury

The transplantation of Wharton’s jelly derived mesenchymal stromal cells (WJ-MSCs) possesses therapeutic potential for the treatment of a spinal cord injury (SCI). Generally, the main effect of MSCs is mediated by their paracrine potential. Therefore, application of WJ-MSC derived conditioned media (CM) is an acknowledged approach for how to bypass the limited survival of transplanted cells. In this study, we compared the effect of human WJ-MSCs and their CM in the treatment of SCI in rats. WJ-MSCs and their CM were intrathecally transplanted in the three consecutive weeks following the induction of a balloon compression lesion. Behavioral analyses were carried out up to 9 weeks after the SCI and revealed significant improvement after the treatment with WJ-MSCs and CM, compared to the saline control. Both WJ-MSCs and CM treatment resulted in a higher amount of spared gray and white matter and enhanced expression of genes related to axonal growth. However, only the CM treatment further improved axonal sprouting and reduced the number of reactive astrocytes in the lesion area. On the other hand, WJ-MSCs enhanced the expression of inflammatory and chemotactic markers in plasma, which indicates a systemic immunological response to xenogeneic cell transplantation. Our results confirmed that WJ-MSC derived CM offer an alternative to direct stem cell transplantation for the treatment of SCI.

MIC-1/GDF15 Overexpression Is Associated with Increased Functional Recovery in Traumatic Spinal Cord Injury

Spinal cord injury (SCI) has devastating consequences, with limited therapeutic options; therefore, improving its functional outcome is a major goal. The outcome of SCI is contributed to by neuroinflammation, which may be a target for improved recovery and quality of life after injury. Macrophage inhibitory cytokine-1/growth differentiation factor 15 (MIC-1/GDF15) has been identified as a potential novel therapy for central nervous system (CNS) injury because it is an immune regulatory cytokine with neurotrophic properties. Here we used MIC-1/GDF15 knockout (KO) and overexpressing/transgenic (Tg) and wild type (WT) animals to explore its putative therapeutic benefits in a mouse model of contusive SCI. MIC-1/GDF15 Tg mice had superior locomotor recovery and reduced secondary tissue loss at 28 days compared with their KO and WT counterparts. Overexpression of MIC-1/GDF15 coincided with increased expression of monocyte chemoattractant protein-1 (MCP-1)/C-C Motif Chemokine Ligand 2 (CCL2) at the lesion site (28 days post-SCI) and enhanced recruitment of inflammatory cells to the injured spinal cord. This inflammatory cellular infiltrate included an increased frequency of macrophages and dendritic cells (DCs) that mostly preceded recruitment of cluster of differentiation (CD)4⁺ and CD8⁺ T cells. Collectively, our findings suggest hat MIC-1/GDF15 is associated with beneficial changes in the clinical course of SCI that are characterized by altered post-injury inflammation and improved functional outcome. Further investigation of MIC-1/GDF15 as a novel therapeutic target for traumatic SCI appears warranted.

Ethical development of stem-cell-based interventions

The process of developing new and complex stem-cell-based therapeutics is incremental and requires decades of sustained collaboration among different stakeholders. In this Perspective, we address key ethical and policy challenges confronting the clinical translation of stem-cell-based interventions (SCBIs), including premature diffusion of SCBIs to clinical practice, assessment of risk in trials, obtaining valid informed consent for research participants, balanced and complete scientific reporting and public communications, regulation, and equitable access to treatment. We propose a way forward for translating these therapies with the above challenges in mind.

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.

Circular RNA Expression Alteration and Bioinformatics Analysis in Rats After Traumatic Spinal Cord Injury

Spinal cord injury (SCI) is mostly caused by trauma. As primary mechanical injury is unavoidable in SCI, a focus on the pathophysiology and underlying molecular mechanisms of SCI-induced secondary injury is necessary to develop promising treatments for SCI patients. Circular RNAs (circRNAs) are associated with various diseases. Nevertheless, studies to date have not yet determined the functional roles of circRNAs in traumatic SCI. We examined circRNA expression profiles in the contused spinal cords of rats using microarray and quantitative reverse transcription-PCR (qRT-PCR) then predict their potential roles in post-SCI pathophysiology with bioinformatics. We found a total of 1676 differentially expressed circRNAs (fold change ≥ 2.0; P < 0.05) in spinal cord 3 days after contusion using circRNA microarray; 1261 circRNAs were significantly downregulated, whereas the remaining 415 were significantly upregulated. Then, five selected circRNAs, namely, rno_circRNA_005342, rno_circRNA_015513, rno_circRNA_002948, rno_circRNA_006096, and rno_circRNA_013017 were all significantly downregulated in the SCI group after verification by qRT-PCR, demonstrating a similar expression pattern in both microarray and PCR data. The next section of the study was concerned with the prediction of circRNA/miRNA/mRNA interactions using bioinformatics analysis. In the final part of the study, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses indicated carbohydrate metabolic process was one of the most significant enrichments and meaningful terms after GO analysis, and the top two signaling pathways affected by the circRNAs-miRNAs axes were the AMP-activated protein kinase signaling pathway and the peroxisome related pathway. In summary, this study showed an altered circRNA expression pattern that may be involved in physiological and pathological processes in rats after traumatic SCI, providing deep insights into numerous possibilities for SCI treatment targets by regulating circRNAs.

Effects of low-intensity electrical stimulation and adipose derived stem cells transplantation on the time-domain analysis-based electromyographic signals in dogs with SCI

INTRODUCTION

The application of low-intensity electrical stimulation (LIES) to neural tissue increases neurochemical factors responsible for regeneration as nerve growth factor. Stem cell (SC) therapy for patients with Spinal cord injury (SCI) promote some increase functional improvement.

OBJECTIVE

Investigate the electromyographic response in paraplegic dogs undergoing LIES and SC transplantation.

METHODS

27 dogs paraplegics with SCI were divided into three groups with different types of therapy. G_ADSC: two SC transplants (n = 9); G_LIES: LIES (n = 8); G_COMB: two SC transplants and LIES (n = 10). Adipose derived mesenchymal stem cells (ADSCs) were transplanted by lumbar puncture in the amount of 1.2 × 10⁶ cells/50 μL. Acupuncture needles positioned in the interspinous space were used for stimulation. The electrical stimulation was applied with a mean voltage ∼30 mV and four consecutive modulated frequencies (5 Hz, 10 Hz, 15 Hz and 20 Hz) within 5 min each. The patients motor performance was evaluated before (Pre) the procedure and after 30 (Post₃₀) and 60 (Post₆₀) days, from electromyography root mean square (EMG_RMS) registered with subcutaneous electrodes in the vastus lateralis muscle, while the animals were in quadrupedal position.

RESULTS

All three groups showed a significant intra-group increase of EMG_RMS (Pre vs. Post₃₀ or Pre vs. Post₆₀). However, there were no statistically significant differences between Post₃₀ and Post₆₀. The inter-group test (G_ADSC X G_LIES X G_COMB) did not present significance when compared the instants Pre (p = 0.34), Post₃₀ (p = 0.78) and Post₆₀ (p = 0.64).

CONCLUSION

Some dogs recovered motor activity, expressed by the EMG_RMS, in all groups, in pre vs. post (30 or 60 days) comparisons.

Recent update on basic mechanisms of spinal cord injury

Spinal cord injury (SCI) is a life-shattering neurological condition that affects between 250,000 and 500,000 individuals each year with an estimated two to three million people worldwide living with an SCI-related disability. The incidence in the USA and Canada is more than that in other countries with motor vehicle accidents being the most common cause, while violence being most common in the developing nations. Its incidence is two- to fivefold higher in males, with a peak in younger adults. Apart from the economic burden associated with medical care costs, SCI predominantly affects a younger adult population. Therefore, the psychological impact of adaptation of an average healthy individual as a paraplegic or quadriplegic with bladder, bowel, or sexual dysfunction in their early life can be devastating. People with SCI are two to five times more likely to die prematurely, with worse survival rates in low- and middle-income countries. This devastating disorder has a complex and multifaceted mechanism. Recently, a lot of research has been published on the restoration of locomotor activity and the therapeutic strategies. Therefore, it is imperative for the treating physicians to understand the complex underlying pathophysiological mechanisms of SCI.

A review on stem cell therapy for multiple sclerosis: special focus on human embryonic stem cells

Multiple sclerosis (MS), a complex disorder of the central nervous system (CNS), is characterized with axonal loss underlying long-term progressive disability. Currently available therapies for its management are able to slow down the progression but fail to treat it completely. Moreover, these therapies are associated with major CNS and cardiovascular adverse events, and prolonged use of these treatments may cause life-threatening diseases. Recent research has shown that cellular therapies hold a potential for CNS repair and may be able to provide protection from inflammatory damage caused after injury. Human embryonic stem cell (hESC) transplantation is one of the promising cell therapies; hESCs play an important role in remyelination and help in preventing demylenation of the axons. In this study, an overview of the current knowledge about the unique properties of hESC and their comparison with other cell therapies has been presented for the treatment of patients with MS.