Olfactory mucosa autografts in human spinal cord injury: a pilot clinical study

Adverse events of cell therapy clinical trials in human chronic spinal cord injury, a systematic review and meta-analysis

Spinal cord injury is a lesion with high mortality and significant morbidities. After the primary injury, during six months, a cascade of secondary cellular and molecular events makes the lesion chronic. Recently, cell-based clinical trials as a new procedure have been gradually tested to improve the symptoms of patients. Each treatment method is associated with different adverse events. Based on the PRISMA flow diagram of the identified records, and after multistep screening, finally in 76 reviewed studies with 1633 cases and 189 controls, 64 types of adverse events in 12 categories were recorded in 45 studies. The most common adverse events were transient backache and meningism (90%) and cord malacia (80%). The cell therapy method in which the treatment was associated with more adverse events was Olfactory ensheathing cell and bone marrow mesenchymal stem cell combination therapy in 55%, and the adverse events were less with the embryonic stem cell in 2.33% of patients. In a meta-analysis, the total prevalence of adverse events in cell therapy was 19% and the highest pulled effect size belonged to urinary tract and localized adverse events. Also, the total prevalence of adverse events in 14 cell therapy methods was 18% and four cell types (neural stem cell, bone marrow hematopoietic stem cell, embryonic stem cell, and umbilical cord mesenchymal stem cell) had the most effect. None of the adverse events were reported on the 4 (life-threatening consequences) and 5 (death) grading scales. We concluded that the frequency of life-threatening adverse events following cell therapy clinical trials in chronic spinal cord injury patients is very scarce and can be ignored.

The anti-inflammatory and immunomodulatory effects of olfactory ensheathing cells transplantation in spinal cord injury and concomitant pathological pain

Spinal cord injury (SCI) is a serious and disabling injury that is often accompanied by neuropathic pain (NeP), which severely affects patients' motor and sensory functions and reduces their quality of life. Currently, there is no specific treatment for treating SCI and relieving the accompanying pain, and we can only rely on medication and physical rehabilitation, both of which are ineffective. Researchers have recently identified a novel class of glial cells, olfactory ensheathing cells (OECs), which originate from the olfactory system. Transplantation of OECs into damaged spinal cords has demonstrated their capacity to repair damaged nerves, improve the microenvironment at the point of injury, and They can also restore neural connectivity and alleviate the patient's NeP to a certain extent. Although the effectiveness of OECs transplantation has been confirmed in experiments, the specific mechanisms by which it repairs the spinal cord and relieves pain have not been articulated. Through a review of the literature, it has been established that the ability of OECs to repair and relieve pain is inextricably linked to its anti-inflammatory and immunomodulatory effects. In this regard, it is imperative to gain a deeper understanding of how OECs exert their anti-inflammatory and immunomodulatory effects. The objective of this paper is to provide a comprehensive overview of the mechanisms by which OECs exert anti-inflammatory and immunomodulatory effects. We aim to manipulate the immune microenvironment at the transplantation site through the intervention of cytokines and immune cells, with the goal of enhancing OECs' function or creating a conducive microenvironment for OECs' survival. This approach is expected to improve the therapeutic efficacy of OECs in clinical settings. However, numerous fundamental and clinical challenges remain to be addressed if OEC transplantation therapy is to become a standardized treatment in clinical practice.

Management of traumatic spinal cord injury: A current concepts review of contemporary and future treatment

Spinal Cord Injury (SCI) is a condition leading to inflammation, edema, and dysfunction of the spinal cord, most commonly due to trauma, tumor, infection, or vascular disturbance. Symptoms include sensory and motor loss starting at the level of injury; the extent of damage depends on injury severity as detailed in the ASIA score. In the acute setting, maintaining mean arterial pressure (MAP) higher than 85 mmHg for up to 7 days following injury is preferred; although caution must be exercised when using vasopressors such as phenylephrine due to serious side effects such as pulmonary edema and death. Decompression surgery (DS) may theoretically relieve edema and reduce intraspinal pressure, although timing of surgery remains a matter of debate. Methylprednisolone (MP) is currently used due to its ability to reduce inflammation but more recent studies question its clinical benefits, especially with inconsistency in recommending it nationally and internationally. The choice of MP is further complicated by conflicting evidence for optimal timing to initiate treatment, and by the reported observation that higher doses are correlated with increased risk of complications. Thyrotropin-releasing hormone may be beneficial in less severe injuries. Finally, this review discusses many options currently being researched and have shown promising pre-clinical results.

Systematic Review of Cell Therapy Efficacy in Human Chronic Spinal Cord Injury

Spinal cord injury (SCI) is one of the most debilitating problems for humans. About 6 months after the initial injury, a cascade of secondary cellular and molecular events occurs and the primary damage enters the chronic phase. Current treatments are not curative. One of the new treatment methods is the use of cell therapy, which is gradually being tested in clinical trials to improve the symptoms of SCI patients. In this review article, we investigated the effect of different cell therapy trials in improving patients' symptoms and their paraclinical indicators. In the 72 final reviewed studies with 1144 cases and 186 controls, 20 scores were recorded as outcomes. We categorized the scores into seven groups. In upper extremity motor score, daily living function, trunk stability, postural hypotension, somatosensory evoked potential, and motor evoked potential scores, the bone marrow hematopoietic stem cell therapy had a more healing effect. In the International Association of Neurorestoratology SCI Functional Rating Scale, light touch score, bowel function, decreased spasticity, Visual Analog Scale, and electromyography scores, the bone marrow mesenchymal stem cell had more impact. The olfactory ensheathing cell had a greater effect on lower extremity motor score and pinprick scores than other cells. The embryonic stem cell had the greatest effect in improving the important score of the American Spinal Injury Association scale. Based on the obtained results, it seems that a special cell should be used to improve each symptom of patients with chronic SCI, and if the improvement of several harms is involved, the combination of cells may be effective. Impact statement Compared to similar review articles published so far, we reviewed the largest number of published articles, and so the largest number of cases and controls, and the variety of cells we examined was more than other published articles. We concluded that different cells are effective for improving the symptoms and paraclinical indicators of patients with chronic spinal cord injury. Bone marrow hematopoietic stem cell and bone marrow mesenchymal stem cell have had the higher overall mean effect in more scores (each in six scores). If the improvement of several harms is involved, the combination of cells may be effective.

A Novel Approach for Mucosal and Bulbar Olfactory Ensheathing Cells Isolation Based on the Non-adherent Subculture Technique

Introduction

Olfactory ensheathing cells (OECs) are widely used in transplantation studies. The high purification of this unique cell type is valuable for medical applications. Although recent improvements in OECs isolation procedures opened a new era in this field, the high purification efficacy and viability rate are still of concern. The most widely used OECs isolation techniques can be broadly classified based on adherence properties, particularly in olfactory bulb-derived OEC isolation. Considering the invasive nature of harvesting OECs from human olfactory bulbs, a highly efficient purification of these cells from olfactory mucosa can benefit clinical trials. In this study, we isolated OECs from rats' olfactory bulbs and mucosa due to their differential adherence properties and compared them.

Methods

Cell preparations were characterized by NGFR p75 and S100β antibodies, the specific markers for OECs, using immunocytochemistry and western blot analysis, respectively. OECs morphology and viability were monitored over time by microscopy and MTT (3-[4,5-dimethylthiazol2-yl]-2,5-diphenyltetrazolium bromide) assay.

Results

We found that OECs could be purified from the olfactory mucosa using our suggested method as efficiently as the olfactory bulb. Both derived OECs showed high levels of NGFR p75 and S100β expression, although the S100β expression was higher in olfactory mucosa-derived OECs preparations (P<0.05). Moreover, there was no significant difference between the two sources in cell viability in our suggested protocol.

Conclusion

Due to the non-invasive harvesting method, olfactory mucosa-derived OECs are preferred from a clinical point of view in transplantation studies.

Expansive Spinal Cord Injury After Autologous Olfactory Mucosal Transplantation: Case Report and Systematic Review

OBJECTIVE

To present strategies for managing tumor mass formation and their corresponding postoperative outcomes.

METHODS

We conducted a systematic literature review following the guidelines and protocol of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched the PubMed and EMBASE databases, screened titles and abstracts, and further evaluated full-text publications to select relevant studies. Additionally, a narrative review of other pertinent articles on PubMed was performed. Case reports, cohort studies, and clinical trials were included. Animal studies were excluded.

RESULTS

Of 6 patients enrolled in this study, most had American Spinal Injury Association Impairment Scale grade A (66.7%) following intramedullary injury, and 1 patient had American Spinal Injury Association Impairment Scale grade D (16.65%). The discovery time of the intramedullary mass formation ranged from approximately 5 to 14 years. Surgical intervention was performed in most cases (66.7%), with improvement reported in 3 of the surgical cases (75%). The majority of cases (83.3%) involved cervical lesions, while only 1 case (16.7%) involved a thoracic lesion.

CONCLUSIONS

Due to the scarcity of described cases, there is no specific treatment for this tumor. Although our patient remained stable after conservative treatment, other studies have shown improvement in symptoms after mass resection. It is essential that the management of this complication be researched further due to the variety of clinical characteristics presented.

Fluoxetine enhances the antitumor effect of olfactory ensheathing cell-thymidine kinase/ganciclovir gene therapy in human glioblastoma multiforme cells through upregulation of Connexin43 levels

Glioblastoma multiforme (GBM) is the most invasive form of primary brain astrocytoma, resulting in poor clinical outcomes. Herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy is considered a promising strategy for GBM treatment. Since Connexin43 (Cx43) expression is reduced in GBM cells, increasing Cx43 levels could enhance the effectiveness of gene therapy. The present study aims to examine the impact of fluoxetine on HSV-TK/GCV gene therapy in human GBM cells using human olfactory ensheathing cells (OECs) as vectors. The effect of fluoxetine on Cx43 levels was assessed using the western blot technique. GBM-derived astrocytes and OECs-TK were Cocultured, and the effect of fluoxetine on the Antitumor effect of OEC-TK/GCV gene therapy was evaluated using MTT assay and flow cytometry. Our results showed that fluoxetine increased Cx43 levels in OECs and GBM cells and augmented the killing effect of OECs-TK on GBM cells. Western blot data revealed that fluoxetine enhanced the Bax/Bcl2 ratio and the levels of cleaved caspase-3 in the coculture of OECs-TK and GBM cells. Moreover, flow cytometry data indicated that fluoxetine increased the percentage of apoptotic cells in the coculture system. This study suggests that fluoxetine, by upregulating Cx43 levels, could strengthen the Antitumor effect of OEC-TK/GCV gene therapy on GBM cells.

Use of Cells, Supplements, and Peptides as Therapeutic Strategies for Modulating Inflammation after Spinal Cord Injury: An Update

Spinal cord injury is a traumatic lesion that causes a catastrophic condition in patients, resulting in neuronal deficit and loss of motor and sensory function. That loss is caused by secondary injury events following mechanical damage, which results in cell death. One of the most important events is inflammation, which activates molecules like proinflammatory cytokines (IL-1β, IFN-γ, and TNF-α) that provoke a toxic environment, inhibiting axonal growth and exacerbating CNS damage. As there is no effective treatment, one of the developed therapies is neuroprotection of the tissue to preserve healthy tissue. Among the strategies that have been developed are the use of cell therapy, the use of peptides, and molecules or supplements that have been shown to favor an anti-inflammatory environment that helps to preserve tissue and cells at the site of injury, thus favoring axonal growth and improved locomotor function. In this review, we will explain some of these strategies used in different animal models of spinal cord injury, their activity as modulators of the immune system, and the benefits they have shown.

Cell therapies for spinal cord injury: a review of the clinical trials and cell-type therapeutic potential

Spinal cord injury (SCI) is an as yet untreatable neuropathology that causes severe dysfunction and disability. Cell-based therapies hold neuroregenerative and neuroprotective potential, but, although being studied in SCI patients for more than two decades, long-term efficacy and safety remain unproven, and which cell types result in higher neurological and functional recovery remains under debate. In a comprehensive scoping review of 142 reports and registries of SCI cell-based clinical trials, we addressed the current therapeutical trends and critically analysed the strengths and limitations of the studies. Schwann cells, olfactory ensheathing cells (OECs), macrophages and various types of stem cells have been tested, as well as combinations of these and other cells. A comparative analysis between the reported outcomes of each cell type was performed, according to gold-standard efficacy outcome measures like the ASIA impairment scale, motor and sensory scores. Most of the trials were in the early phases of clinical development (phase I/II), involved patients with complete chronic injuries of traumatic aetiology and did not display a randomized comparative control arm. Bone marrow stem cells and OECs were the most commonly tested cells, while open surgery and injection were the main methods of delivering cells into the spinal cord or submeningeal spaces. Transplantation of support cells, such as OECs and Schwann cells, resulted in the highest ASIA Impairment Scale (AIS) grade conversion rates (improvements in ∼40% of transplanted patients), which surpassed the spontaneous improvement rate expected for complete chronic SCI patients within 1 year post-injury (5-20%). Some stem cells, such as peripheral blood-isolated and neural stem cells, offer potential for improving patient recovery. Complementary treatments, particularly post-transplantation rehabilitation regimes, may contribute highly to neurological and functional recovery. However, unbiased comparisons between the tested therapies are difficult to draw, given the great heterogeneity of the design and outcome measures used in the SCI cell-based clinical trials and how these are reported. It is therefore crucial to standardize these trials when aiming for higher value clinical evidence-based conclusions.

Innovations in cell therapy in pediatric diseases: a narrative review

Background and Objective

Stem cell therapy is a regenerative medicine modality that has the potential to decrease morbidity and mortality by promoting tissue regeneration or modulating the inflammatory response. An increase in the number of clinical trials investigating the efficacy and safety of stem cell therapy in pediatric diseases has led to advancements in this field. Currently, multiple sources and types of stem cells have been utilized in the treatment of pediatric diseases. This review aims to inform researchers and clinicians about preclinical and clinical stem cell therapy trials in pediatric patients. We discuss the different types of stem cells and the wide spectrum of stem cell therapy trials for pediatric diseases, with an emphasis on the outcomes and advancements in the field.

Methods

PubMed and clinicaltrials.gov databases were searched on October 28, 2022 using the following Medical Subject Headings (MeSH) terms "stem cell" or "stem cell therapy" with an age filter <18 years. Our search was limited to publications published between 2000 and 2022.

Key Content and Findings

Diverse sources of stem cells have different properties and mechanisms of action, which allow tailored application of stem cells according to the pathophysiology of the disease. Advancements in stem cell therapies for pediatric diseases have led to improvements in clinical outcomes in some pediatric diseases or in quality of life, such therapies represent a potential alternative to the current treatment modalities.

Conclusions

Stem cell therapy in pediatric diseases has shown promising results and outcomes. However, further studies focusing on the implementation and optimal treatment timeframe are needed. An increase in preclinical and clinical trials of stem cell therapy targeting pediatric patients is required to advance our therapeutic applications.

Immune response following traumatic spinal cord injury: Pathophysiology and therapies

Traumatic spinal cord injury (SCI) is a devastating condition that is often associated with significant loss of function and/or permanent disability. The pathophysiology of SCI is complex and occurs in two phases. First, the mechanical damage from the trauma causes immediate acute cell dysfunction and cell death. Then, secondary mechanisms of injury further propagate the cell dysfunction and cell death over the course of days, weeks, or even months. Among the secondary injury mechanisms, inflammation has been shown to be a key determinant of the secondary injury severity and significantly worsens cell death and functional outcomes. Thus, in addition to surgical management of SCI, selectively targeting the immune response following SCI could substantially decrease the progression of secondary injury and improve patient outcomes. In order to develop such therapies, a detailed molecular understanding of the timing of the immune response following SCI is necessary. Recently, several studies have mapped the cytokine/chemokine and cell proliferation patterns following SCI. In this review, we examine the immune response underlying the pathophysiology of SCI and assess both current and future therapies including pharmaceutical therapies, stem cell therapy, and the exciting potential of extracellular vesicle therapy.

Clinical characteristics and treatment of spinal cord injury in children and adolescents

Pediatric and adult spinal cord injuries (SCI) are distinct entities. Children and adolescents with SCI must suffer from lifelong disabilities, which is a heavy burden on patients, their families and the society. There are differences in Chinese and foreign literature reports on the incidence, injury mechanism and prognosis of SCI in children and adolescents. In addition to traumatic injuries such as car accidents and falls, the proportion of sports injuries is increasing. The most common sports injury is the backbend during dance practice. Compared with adults, children and adolescents are considered to have a greater potential for neurological improvement. The pathogenesis and treatment of pediatric SCI remains unclear. The mainstream view is that the mechanism of nerve damage in pediatric SCI include flexion, hyperextension, longitudinal distraction and ischemia. We also discuss the advantages and disadvantages of drugs such as methylprednisolone in the treatment of pediatric SCI and the indications and timing of surgery. In addition, the complications of pediatric SCI are also worthy of attention. New imaging techniques such as diffusion tensor imaging and diffusion tensor tractography may be used for diagnosis and assessment of prognosis. This article reviews the epidemiology, pathogenesis, imaging, clinical characteristics, treatment and complications of SCI in children and adolescents. Although current treatment cannot completely restore neurological function, patient quality of life can be enhanced. Continued developments and advances in the research of SCI may eventually provide a cure for children and adolescents with this kind of injury.

Designing a Clinical Trial with Olfactory Ensheathing Cell Transplantation-Based Therapy for Spinal Cord Injury: A Position Paper

Spinal cord injury (SCI) represents an urgent unmet need for clinical reparative therapy due to its largely irreversible and devastating effects on patients, and the tremendous socioeconomic burden to the community. While different approaches are being explored, therapy to restore the lost function remains unavailable. Olfactory ensheathing cell (OEC) transplantation is a promising approach in terms of feasibility, safety, and limited efficacy; however, high variability in reported clinical outcomes prevent its translation despite several clinical trials. The aims of this position paper are to present an in-depth analysis of previous OEC transplantation-based clinical trials, identify existing challenges and gaps, and finally propose strategies to improve standardization of OEC therapies. We have reviewed the study design and protocols of clinical trials using OEC transplantation for SCI repair to investigate how and why the outcomes show variability. With this knowledge and our experience as a team of biologists and clinicians with active experience in the field of OEC research, we provide recommendations regarding cell source, cell purity and characterisation, transplantation dosage and format, and rehabilitation. Ultimately, this position paper is intended to serve as a roadmap to design an effective clinical trial with OEC transplantation-based therapy for SCI repair.

Visualization of ex vivo rabbit olfactory mucosa and foramina with three-dimensional optical coherence tomography

There is increasing interest in developing a minimally invasive imaging modality to safely evaluate dynamic microscopic changes of the olfactory mucosa and cribriform foramina. Herein, we utilized three-dimensional (3D) optical coherence tomography (OCT) to characterize the ex vivo stratified substructure of olfactory mucosa in rabbits and create 3D reconstructed images of olfactory foramina. Olfactory mucosa and cribriform plates from four New Zealand White rabbits were dissected and imaged using two swept-source OCT systems: (1) 1.3-µm (μm) center wavelength, 100-nm bandwidth, 200-kHz sweep rate, and (2) 1.7-μm center wavelength, 120-nm bandwidth, 90-kHz sweep rate. Volumetric OCT images were compiled to create a 3D reconstruction of the cribriform plate. The ability of OCT to distinguish the olfactory mucosa substructure and foramina was compared to histology. To estimate imaging penetration depth of each system, the first-order exponential decays of depth-resolved intensity were calculated and compared using a paired t-test. Three-dimensional OCT depicted the stratified layered structures within the olfactory mucosa correlating with histology. The epithelium and lamina propria were measured to be 32 μm and 107 μm in 1.3-μm OCT compared to 30 μm and 105 μm in histology. Olfactory foramina were visualized via 3D reconstruction. The 1.7-μm system provided greater depth penetration compared to the 1.3-μm system, allowing for improved foramina visualization. We have shown that OCT can be used to image non-pathologic olfactory mucosa and foramina. Implications for this work include diagnostic and therapeutic potentials for neurorhinological and neurodegenerative diseases.

Comparing the Efficacy and Safety of Cell Transplantation for Spinal Cord Injury: A Systematic Review and Bayesian Network Meta-Analysis

Objective

To compare the safety and effectiveness of transplanted cells from different sources for spinal cord injury (SCI).

Design

A systematic review and Bayesian network meta-analysis.

Data Sources

Medline, Embase, and the Cochrane Central Register of Controlled Trials.

Study Selection

We included randomized controlled trials, case–control studies, and case series related to cell transplantation for SCI patients, that included at least 1 of the following outcome measures: American Spinal Cord Injury Association (ASIA) Impairment Scale (AIS grade), ASIA motor score, ASIA sensory score, the Functional Independence Measure score (FIM), International Association of Neurorestoratology Spinal Cord Injury Functional Rating Scale (IANR-SCIFRS), or adverse events. Follow-up data were analyzed at 6 and 12 months.

Results

Forty-four eligible trials, involving 1,266 patients, investigated 6 treatments: olfactory ensheathing cells (OECs), neural stem cells/ neural progenitor cells (NSCs), mesenchymal stem cells (MSCs), Schwann cells, macrophages, and combinations of cells (MSCs plus Schwann cells). Macrophages improved the AIS grade at 12 months (mean 0.42, 95% credible interval: 0–0.91, low certainty) and FIM score at 12 months (42.83, 36.33–49.18, very low certainty). MSCs improved the AIS grade at 6 months (0.42, 0.15–0.73, moderate certainty), the motor score at 6 months (4.43, 0.91–7.78, moderate certainty), light touch at 6 (10.01, 5.81–13.88, moderate certainty) and 12 months (11.48, 6.31–16.64, moderate certainty), pinprick score at 6 (14.54, 9.76–19.46, moderate certainty) and 12 months (12.48, 7.09–18.12, moderate certainty), and the IANR-SCIFRS at 6 (3.96, 0.62–6.97, moderate certainty) and 12 months (5.54, 2.45–8.42, moderate certainty). OECs improved the FIM score at 6 months (9.35, 1.71–17.00, moderate certainty). No intervention improved the motor score significantly at 12 months. The certainty of other interventions was low or very low. Overall, the number of adverse events associated with transplanted cells was low.

Conclusions

Patients with SCI who receive transplantation of macrophages, MSCs, NSCs, or OECs may have improved disease prognosis. MSCs are the primary recommendations. Further exploration of the mechanism of cell transplantation in the treatment of SCI, transplantation time window, transplantation methods, and monitoring of the number of transplanted cells and cell survival is needed.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier: CRD 42021282043.

Mapping the long rocky road to effective spinal cord injury therapy - A meta-review of pre-clinical and clinical research

Spinal cord injury (SCI) is a rare condition, which even after decades of research, to date still presents an incurable condition with a complex symptomatology. SCI can result in paralysis, pain, loss of sensation, bladder and sexual dysfunction, and muscle degeneration to name but a few. The large number of publications makes it difficult to keep track of current progress in the field and of the many treatment options, which have been suggested and are being proposed with increasing frequency. Scientific databases with user-oriented search options will offer possible solutions, but they are still mostly in the development phase. In this meta-analysis, we summarize and narrow down SCI therapeutic approaches applied in pre-clinical and clinical research. Statistical analyses of treatment clusters - assorted after counting annual publication numbers in PubMed and ClinicalTrials.gov databases - were performed to allow the comparison of research foci and of their translation efficacy into clinical therapy. Using the example of SCI research, our findings demonstrate the challenges that come with the accelerating research progress - an issue, which many research fields are faced with today. The analyses point out similarities and differences in the prioritization of SCI research in pre-clinical versus clinical therapy strategies. Moreover, the results demonstrate the rapidly growing importance of modern (bio-)engineering technologies.

Are Cell-Based Therapies Safe and Effective in the Treatment of Neurodegenerative Diseases? A Systematic Review with Meta-Analysis

Over the past two decades, significant advances have been made in the field of regenerative medicine. However, despite being of the utmost clinical urgency, there remains a paucity of therapeutic strategies for conditions with substantial neurodegeneration such as (progressive) multiple sclerosis (MS), spinal cord injury (SCI), Parkinson's disease (PD) and Alzheimer's disease (AD). Different cell types, such as mesenchymal stromal cells (MSC), neuronal stem cells (NSC), olfactory ensheathing cells (OEC), neurons and a variety of others, already demonstrated safety and regenerative or neuroprotective properties in the central nervous system during the preclinical phase. As a result of these promising findings, in recent years, these necessary types of cell therapies have been intensively tested in clinical trials to establish whether these results could be confirmed in patients. However, extensive research is still needed regarding elucidating the exact mechanism of action, possible immune rejection, functionality and survival of the administered cells, dose, frequency and administration route. To summarize the current state of knowledge, we conducted a systematic review with meta-analysis. A total of 27,043 records were reviewed by two independent assessors and 71 records were included in the final quantitative analysis. These results show that the overall frequency of serious adverse events was low: 0.03 (95% CI: 0.01-0.08). In addition, several trials in MS and SCI reported efficacy data, demonstrating some promising results on clinical outcomes. All randomized controlled studies were at a low risk of bias due to appropriate blinding of the treatment, including assessors and patients. In conclusion, cell-based therapies in neurodegenerative disease are safe and feasible while showing promising clinical improvements. Nevertheless, given their high heterogeneity, the results require a cautious approach. We advocate for the harmonization of study protocols of trials investigating cell-based therapies in neurodegenerative diseases, adverse event reporting and investigation of clinical outcomes.

Human olfactory mesenchymal stromal cell transplantation ameliorates experimental autoimmune encephalomyelitis revealing an inhibitory role for IL16 on myelination

One of the therapeutic approaches for the treatment of the autoimmune demyelinating disease, multiple sclerosis (MS) is bone marrow mesenchymal stromal cell (hBM-MSCs) transplantation. However, given their capacity to enhance myelination in vitro, we hypothesised that human olfactory mucosa-derived MSCs (hOM-MSCs) may possess additional properties suitable for CNS repair. Herein, we have examined the efficacy of hOM-MSCs versus hBM-MSCs using the experimental autoimmune encephalomyelitis (EAE) model. Both MSC types ameliorated disease, if delivered during the initial onset of symptomatic disease. Yet, only hOM-MSCs improved disease outcome if administered during established disease when animals had severe neurological deficits. Histological analysis of spinal cord lesions revealed hOM-MSC transplantation reduced blood–brain barrier disruption and inflammatory cell recruitment and enhanced axonal survival. At early time points post-hOM-MSC treatment, animals had reduced levels of circulating IL-16, which was reflected in both the ability of immune cells to secrete IL-16 and the level of IL-16 in spinal cord inflammatory lesions. Further in vitro investigation revealed an inhibitory role for IL-16 on oligodendrocyte differentiation and myelination. Moreover, the availability of bioactive IL-16 after demyelination was reduced in the presence of hOM-MSCs. Combined, our data suggests that human hOM-MSCs may have therapeutic benefit in the treatment of MS via an IL-16-mediated pathway, especially if administered during active demyelination and inflammation.

Safety and feasibility of autologous olfactory ensheathing cell and bone marrow mesenchymal stem cell co-transplantation in chronic human spinal cord injury: a clinical trial

STUDY DESIGN

This is a phase I clinical trial.

OBJECTIVES

Our objective was to assess the safety and feasibility of autologous mucosal olfactory ensheathing cell (OEC) and bone marrow mesenchymal stem cell (MSC) co-transplantation in people with chronic, complete (American Spinal Injury Association (ASIA) Impairment Scale (AIS) classification A) spinal cord injury (SCI).

SETTING

This study was performed at Shohada Tajrish Hospital, Tehran, Iran.

METHODS

Three individuals with the traumatic SCI of the thoracic level were enrolled. They received the autologous OEC and MSC combination through the lumbar puncture. All adverse events and possible functional outcomes were documented performing pre- and post-operative general clinical examination, magnetic resonance imaging (MRI), neurological assessment based on the International Standard of Neurological Classification for SCI, and functional evaluation using Spinal Cord Independence Measure version III (SCIM III).

RESULTS

No serious safety issue was recorded during the 2 years of follow-up. MRI findings remained unchanged with no neoplastic tissue formation. AIS improved from A to B in one of the participants. SCIM III evaluation also showed some degrees of progress in this participant's functional ability. The two other research participants had negligible or no improvement in their sensory scores without any changes in the AIS and SCIM III scores. No motor recovery was observed in any of the participants.

CONCLUSIONS

Overall, this 2-year trial was not associated with any adverse findings, which may suggest the safety of autologous OEC and bone marrow MSC combination for the treatment of human SCI.

Spinal Cord Repair: From Cells and Tissue Engineering to Extracellular Vesicles

Spinal cord injury (SCI) is a debilitating condition, often leading to severe motor, sensory, or autonomic nervous dysfunction. As the holy grail of regenerative medicine, promoting spinal cord tissue regeneration and functional recovery are the fundamental goals. Yet, effective regeneration of injured spinal cord tissues and promotion of functional recovery remain unmet clinical challenges, largely due to the complex pathophysiology of the condition. The transplantation of various cells, either alone or in combination with three-dimensional matrices, has been intensively investigated in preclinical SCI models and clinical trials, holding translational promise. More recently, a new paradigm shift has emerged from cell therapy towards extracellular vesicles as an exciting "cell-free" therapeutic modality. The current review recapitulates recent advances, challenges, and future perspectives of cell-based spinal cord tissue engineering and regeneration strategies.

High-Yield Mucosal Olfactory Ensheathing Cells Restore Loss of Function in Rat Dorsal Root Injury

In a previous study, we reported that no axons were crossing from the severed dorsal roots to the spinal cord using the rat dorsal rhizotomy paradigm. The injury caused ipsilateral deficits of forepaw function. An attempt to restore the function by transplanting cells containing 5% olfactory ensheathing cells (OECs) cultured from the olfactory mucosa did not succeed. However, obtaining OECs from the olfactory mucosa has an advantage for clinical application. In the present study, we used the same rhizotomy paradigm, but rats with an injury received cells from a modified mucosal culture containing around 20% OECs mixed in collagen. The forelimb proprioception assessment showed that 80% of the rats receiving the transplants had functional improvement over six weeks of the study. The adhesive removal test showed that the time taken for the rats to notice the adhesive label and remove it almost returned to the normal level after receiving the transplants. Transplanted cells were identified with the expression of green fluorescent protein (ZsGreen). Some regeneration fibres immunostained for neurofilament (NF) or traced by biotinylated dextran amine (BDA) in the injury area were associated with the transplanted cells. The evidence in this study improves the prospect of clinical application using OECs from the olfactory mucosa to treat CNS injuries.

Therapeutic Potential of Niche-Specific Mesenchymal Stromal Cells for Spinal Cord Injury Repair

The use of mesenchymal stem/stromal cells (MSCs) for transplant-mediated repair represents an important and promising therapeutic strategy after spinal cord injury (SCI). The appeal of MSCs has been fuelled by their ease of isolation, immunosuppressive properties, and low immunogenicity, alongside the large variety of available tissue sources. However, despite reported similarities in vitro, MSCs sourced from distinct tissues may not have comparable biological properties in vivo. There is accumulating evidence that stemness, plasticity, immunogenicity, and adaptability of stem cells is largely controlled by tissue niche. The extrinsic impact of cellular niche for MSC repair potential is therefore important, not least because of its impact on ex vivo expansion for therapeutic purposes. It is likely certain niche-targeted MSCs are more suited for SCI transplant-mediated repair due to their intrinsic capabilities, such as inherent neurogenic properties. In addition, the various MSC anatomical locations means that differences in harvest and culture procedures can make cross-comparison of pre-clinical data difficult. Since a clinical grade MSC product is inextricably linked with its manufacture, it is imperative that cells can be made relatively easily using appropriate materials. We discuss these issues and highlight the importance of identifying the appropriate niche-specific MSC type for SCI repair.

Significance of the neurological level of injury as a prognostic predictor for motor complete cervical spinal cord injury patients

OBJECTIVE

To investigate the usefulness of the combination of neurological findings and magnetic resonance imaging (MRI) as a prognostic predictor in patients with motor complete cervical spinal cord injury (CSCI) in the acute phase.

DESIGN

A cross-sectional analysis.

SETTING

Department of Orthopaedic Surgery, Spinal Injuries Center.

PARTICIPANTS/METHODS

Forty-two patients with an initial diagnosis of motor complete CSCI (AIS A, n = 29; AIS B, n = 13) within 72 h after injury were classified into the recovery group (Group R) and the non-recovery group (Group N), based on the presence or absence of motor recovery (conversion from AIS A/B to C/D) at three months after injury, respectively. The Neurological Level of Injury (NLI) at the initial diagnosis was investigated and the presumptive primary injured segment of the spinal cord was inferred from MRI performed at the initial diagnosis. We investigated whether or not the difference between the presumptive primary injured segment and the NLI exceeded one segment. The presence of a difference between the presumptive primary injured segment and the NLI was compared between Groups R and N.

RESULTS

The number of cases with the differences between the presumptive primary injured segment and the NLI was significantly higher in Group N than in Group R.

CONCLUSION

The presence of differences between the presumptive primary injured segment and the NLI might be a poor improving prognostic predictor for motor complete CSCI. The NLI may be useful for predicting the recovery potential of patients with motor complete CSCI when combined with the MRI findings.

Review of operative considerations in spinal cord stem cell therapy

Spinal cord injury (SCI) can permanently impair motor and sensory function and has a devastating cost to patients and the United States healthcare system. Stem cell transplantation for treatment of SCI is a new technique aimed at creating biological functional recovery. Operative techniques in stem cell transplantation for SCI are varied. We review various clinical treatment paradigms, surgical techniques and technical considerations important in SCI treatment. The NCBI PubMed database was queried for “SCI” and “stem cell” with a filter placed for “clinical trials”. Thirty-nine articles resulted from the search and 29 were included and evaluated by study authors. A total of 10 articles were excluded (9 not SCI focused or transplantation focused, 1 canine model). Key considerations for stem cell transplantation include method of delivery (intravenous, intrathecal, intramedullary, or excision and engraftment), time course of treatment, number of treatments and time from injury until treatment. There are no phase III clinical trials yet, but decreased time from injury to treatment and a greater number of stem cell injections both seem to increase the chance of functional recovery.

Delivery of chondroitinase by canine mucosal olfactory ensheathing cells alongside rehabilitation enhances recovery after spinal cord injury

Spinal cord injury (SCI) can cause chronic paralysis and incontinence and remains a major worldwide healthcare burden, with no regenerative treatment clinically available. Intraspinal transplantation of olfactory ensheathing cells (OECs) and injection of chondroitinase ABC (chABC) are both promising therapies but limited and unpredictable responses are seen, particularly in canine clinical trials. Sustained delivery of chABC presents a challenge due to its thermal instability; we hypothesised that transplantation of canine olfactory mucosal OECs genetically modified ex vivo by lentiviral transduction to express chABC (cOEC-chABC) would provide novel delivery of chABC and synergistic therapy. Rats were randomly divided into cOEC-chABC, cOEC, or vehicle transplanted groups and received transplant immediately after dorsal column crush corticospinal tract (CST) injury. Rehabilitation for forepaw reaching and blinded behavioural testing was conducted for 8 weeks. We show that cOEC-chABC transplanted animals recover greater forepaw reaching accuracy on Whishaw testing and more normal gait than cOEC transplanted or vehicle control rats. Increased CST axon sprouting cranial to the injury and serotonergic fibres caudal to the injury suggest a mechanism for recovery. We therefore demonstrate that cOECs can deliver sufficient chABC to drive modest functional improvement, and that this genetically engineered cellular and molecular approach is a feasible combination therapy for SCI.

Olfactory ensheathing cells: Unique glial cells promising for treatments of spinal cord injury

Spinal cord injury (SCI) is generally the consequence of physical damage, which may result in devastating consequences such as paraplegia or paralysis. Some certain candidates for SCI repair are olfactory ensheathing cells (OECs), which are unique glial cells located in the transition region of the peripheral nervous system and central nervous system and perform neuron regeneration in the olfactory system throughout life. Culture studies have clarified many properties of OECs, but their mechanisms of actions are not fully understood. Successful results achieved in animal models showcased that SCI treatment with OEC transplants is suitable for clinical trials. However, clinical trials are limited by difficulties like cell acquisition for autograft transplantation. Despite the improvements in both animal and clinical studies so far, there is still insufficient information about the mechanism of actions, adverse effects, proper application methods, effective subtypes, and sources of cells. This review summarizes pre-clinical and clinical literature focused on the cellular characterization of both OECs in vitro and post-transplantation. We highlight the roles and effects of OECs on (a) the injury-induced glial milieu, (b) neuronal growth/regeneration, and (c) functional recovery after injury. Due to the shown benefits of OECs with in vitro and animal studies and a limited number of clinical trials, where safety and effectivity were shown, it is necessary to conduct more studies on OECs to obtain effective and feasible treatment methods.

Autograft-derived spinal cord mass in the cervical spine following transplantation with olfactory mucosa cells for traumatic spinal cord injury: case report

This study describes a patient with an autograft-derived spinal cord mass following transplantation of olfactory mucosa for treatment of cervical spine injury. The authors report the case of a 35-year-old man who suffered a complete spinal cord injury (SCI) at C5-6 in 2001. The patient underwent an olfactory mucosal cell implantation at the location of injury 4 years following initial trauma. Twelve years later, the patient presented with rapidly progressive decline in upper-extremity function as well as neuropathic pain. Imaging revealed a heterogeneously enhancing intramedullary mass from C3 to C7. At surgery, the patient was found to have a posttransplant mucinous mass. Each mucinous cyst was drained and a portion of the cyst wall was removed. Histological examination demonstrated ciliated epithelium-lined fibrous tissue, submucosal glands, and mucoid material, consistent with a transplant-derived tumor. This case report both documents a rare long-term complication of olfactory mucosal cell transplantation and serves as a cautionary tale encouraging prudent use of novel treatments in a vulnerable population of patients with severe SCI.

Ten years of clinical observation of olfactory ensheathing cell transplantation in patients with spinal cord injury

Objective:

To evaluate the long-term curative efficacy and safety of olfactory ensheathing cell (OEC) transplantation by 10 years of follow-up investigation.

Methods:

A follow-up observation was done on 13 patients with allograft olfactory bulb-derived OEC transplantation from September 2005 to September 2007 at the Second Affiliated Hospital of Xi’an Jiaotong University. After cell purification, amplification, and identification, a 2 × 10⁷/mL cell suspension was prepared for transplantation. In the posterior horn of the spinal cord 0.5 cm distal and proximal to the spinal cord injury zone, 4 needle points were selected to avoid the blood vessels. The needle depth was 3 mm, and the injection volume per point was 10 μL. Postoperatively and at 1 week, 4 weeks, 12 weeks, 24 weeks, 1 year, 3 years, 5 years, and 10 years after the surgery, the patient’s American Spinal Injury Association (ASIA) score, adverse reactions, and other minor observations were assessed.

Results:

All the patients did not have serious complications. No gliomas or other new organisms formed during the 10-year observation period. Eight of 13 patients had improvement in sensory function, and 5 patients showed improvement in motor function. The ASIA acupuncture, light touch, and exercise scores improved significantly 1 year after the surgery, and this improvement continued until the 10-year follow-up period. Three of 13 patients had improvement in defecation and urination, and 1 patient had improved neuralgia after spinal cord injury.

Conclusion:

OEC transplantation is safe and effective in treating spinal cord injury. The observation period of OEC transplantation is 1 to 3 years.

Why is olfactory neuroepithelium?

Currently, most cellular therapeutic effects for nervous diseases cannot be proven in a multicenter, randomized, double-blind placebo-control clinical trials, except for a few kinds of cells such as olfactory ensheathing cells. These cells show significant improvements in functional recovery and quality of life for patients with chronic ischemic stroke. Also, olfactory neuron transplantation has promising neurorestorative effects on patients with vascular dementia. Human olfactory neuroepithelium can spontaneously and sustainably regenerate or produce new olfactory neurons and glial cell types for decades or a lifetime. The neurorestorative mechanisms of olfactory ensheathing cells are well known; however, little is known about the neurorestorative mechanisms of olfactory neurons. Therefore, I hypothesize that the neurorestorative mechanisms of olfactory neurons after transplantation: (1) can well migrate where they are needed and become local functional neurons, as they need to compensate or replace; (2) must be regulated by some special molecular factors to elongate their axons, modulate or direct synapses to correctly recognize and connect the target cells, and integrate functions. Based on olfactory neuroepithelium cells displaying the special characterization, neurorestorative mechanisms, clinical therapeutic achievements, and hypotheses of effective mechanisms, they (olfactory ensheathing cells and olfactory neurons) may be the most efficient instruments of neurorestoration.

Special Issue on Cell Therapy

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Recent Advances in the Regenerative Approaches for Traumatic Spinal Cord Injury: Materials Perspective

Spinal cord injury (SCI) is a devastating health condition that may lead to permanent disabilities and death. Understanding the pathophysiological perspectives of traumatic SCI is essential to define mechanisms that can help in designing recovery strategies. Since central nervous system tissues are notorious for their deficient ability to heal, efforts have been made to identify solutions to aid in restoration of the spinal cord tissues and thus its function. The two main approaches proposed to address this issue are neuroprotection and neuro-regeneration. Neuroprotection involves administering drugs to restore the injured microenvironment to normal after SCI. As for the neuro-regeneration approach, it focuses on axonal sprouting for functional recovery of the injured neural tissues and damaged axons. Despite the progress made in the field, neural regeneration treatment after SCI is still unsatisfactory owing to the disorganized way of axonal growth and extension. Nanomedicine and tissue engineering are considered promising therapeutic approaches that enhance axonal growth and directionality through implanting or injecting of the biomaterial scaffolds. One of these recent approaches is nanofibrous scaffolds that are used to provide physical support to maintain directional axonal growth in the lesion site. Furthermore, these preferable tissue-engineered substrates can afford axonal regeneration by mimicking the extracellular matrix of the neural tissues in terms of biological, chemical, and architectural characteristics. In this review, we discuss the regenerative approach using nanofibrous scaffolds with a focus on their fabrication methods and their properties that define their functionality performed to heal the neural tissue efficiently.

Clinical Trials of Stem Cell Therapy for Cerebral Ischemic Stroke

Despite recent developments in innovative treatment strategies, stroke remains one of the leading causes of death and disability worldwide. Stem cell therapy is currently attracting much attention due to its potential for exerting significant therapeutic effects on stroke patients. Various types of cells, including bone marrow mononuclear cells, bone marrow/adipose-derived stem/stromal cells, umbilical cord blood cells, neural stem cells, and olfactory ensheathing cells have enhanced neurological outcomes in animal stroke models. These stem cells have also been tested via clinical trials involving stroke patients. In this article, the authors review potential molecular mechanisms underlying neural recovery associated with stem cell treatment, as well as recent advances in stem cell therapy, with particular reference to clinical trials and future prospects for such therapy in treating stroke.

The Fate of Transplanted Olfactory Progenitors Is Conditioned by the Cell Phenotypes of the Receiver Brain Tissue in Cocultures

Among the numerous candidates for cell therapy of the central nervous system (CNS), olfactory progenitors (OPs) represent an interesting alternative because they are free of ethical concerns, are easy to collect, and allow autologous transplantation. In the present study, we focused on the optimization of neuron production and maturation. It is known that plated OPs respond to various trophic factors, and we also showed that the use of Nerve Growth Factor (NGF) allowed switching from a 60/40 neuron/glia ratio to an 80/20 one. Nevertheless, in order to focus on the integration of OPs in mature neural circuits, we cocultured OPs in primary cultures obtained from the cortex and hippocampus of newborn mice. When dissociated OPs were plated, they differentiated into both glial and neuronal phenotypes, but we obtained a 1.5-fold higher viability in cortex/OP cocultures than in hippocampus/OP ones. The fate of OPs in cocultures was characterized with different markers such as BrdU, Map-2, and Synapsin, indicating a healthy integration. These results suggest that the integration of transplanted OPs might by affected by trophic factors and the environmental conditions/cell phenotypes of the host tissue. Thus, a model of coculture could provide useful information on key cell events for the use of progenitors in cell therapy.

Clinical Trials of Stem Cell Treatment for Spinal Cord Injury

There are more than one million patients worldwide suffering paralysis caused by spinal cord injury (SCI). SCI causes severe socioeconomic problems not only to the patients and their caregivers but also to society; therefore, the development of innovative treatments is crucial. Many pharmacological therapies have been attempted in an effort to reduce SCI-related damage; however, no single therapy that could dramatically improve the serious long-term sequelae of SCI has emerged. Stem cell transplantation therapy, which can ameliorate damage or regenerate neurological networks, has been proposed as a promising candidate for SCI treatment, and many basic and clinical experiments using stem cells for SCI treatment have been launched, with promising results. However, the cell transplantation methods, including cell type, dose, transplantation route, and transplantation timing, vary widely between trials, and there is no consensus regarding the most effective treatment strategy. This study reviews the current knowledge on this issue, with a special focus on the clinical trials that have used stem cells for treating SCI, and highlights the problems that remain to be solved before the widespread clinical use of stem cells can be adopted.

Reliable cell purification and determination of cell purity: crucial aspects of olfactory ensheathing cell transplantation for spinal cord repair

Transplantation of olfactory ensheathing cells, the glia of the primary olfactory nervous system, has been trialed for spinal cord injury repair with promising but variable outcomes in animals and humans. Olfactory ensheathing cells can be harvested either from the lamina propria beneath the neuroepithelium in the nasal cavity, or from the olfactory bulb in the brain. As these areas contain several other cell types, isolating and purifying olfactory ensheathing cells is a critical part of the process. It is largely unknown how contaminating cells such as fibroblasts, other glial cell types and supporting cells affect olfactory ensheathing cell function post-transplantation; these cells may also cause unwanted side-effects. It is also, however, possible that the presence of some of the contaminant cells can improve outcomes. Here, we reviewed the last decade of olfactory ensheathing cell transplantation studies in rodents, with a focus on olfactory ensheathing cell purity. We analyzed how purification methods and resultant cell purity differed between olfactory mucosa- and olfactory bulb-derived cell preparations. We analyzed how the studies reported on olfactory ensheathing cell purity and which criteria were used to define cells as olfactory ensheathing cells. Finally, we analyzed the correlation between cell purity and transplantation outcomes. We found that olfactory bulb-derived olfactory ensheathing cell preparations are typically purer than mucosa-derived preparations. We concluded that there is an association between high olfactory ensheathing cell purity and favourable outcomes, but the lack of olfactory ensheathing cell-specific markers severely hampers the field.

Clinical neurorestorative cell therapies: Developmental process, current state and future prospective

Clinical cell therapies (CTs) for neurological diseases and cellular damage have been explored for more than 2 decades. According to the United States Food and Drug Administration, there are 2 types of cell categories for therapy, namely stem cell-derived CT products and mature/functionally differentiated cell-derived CT products. However, regardless of the type of CT used, the majority of reports of clinical CTs from either small sample sizes based on single-center phase 1 or 2 unblinded trials or retrospective clinical studies showed effects on neurological improvement and the ability to either partially or temporarily thwart the deteriorating cellular processes of the neurodegenerative diseases. There have been only a few prospective, multicenter, randomized, double- blind placebo-control clinical trials of CTs so far in this developing novel area that have shown negative results, and more clinical trials are needed. This will expand our knowledge in exploring the type of cells that yield promising results and restore damaged neurological structure and functions of the central nervous system based on higher level evidence-based medical data. In this review, we briefly introduce the developmental process, current state, and future prospective for clinical neurorestorative CT.

Current Status and Future Strategies to Treat Spinal Cord Injury with Adult Stem Cells

Spinal cord injury (SCI) is one of the most devastating conditions and many SCI patients suffer neurological sequelae. Stem cell therapies are expected to be beneficial for many patients with central nervous system injuries, including SCI. Adult stem cells (ASCs) are not associated with the risks which embryonic stem cells have such as malignant transformation, or ethical problems, and can be obtained relatively easily. Consequently, many researchers are currently studying the effects of ASCs in clinical trials. The environment of transplanted cells applied in the injured spinal cord differs between the phases of SCI; therefore, many researchers have investigated these phases to determine the optimal time window for stem cell therapy in animals. In addition, the results of clinical trials should be evaluated according to the phase in which stem cells are transplanted. In general, the subacute phase is considered to be optimal for stem cell transplantation. Among various candidates of transplantable ASCs, mesenchymal stem cells (MSCs) are most widely studied due to their clinical safety. MSCs are also less immunogenic than neural stem/progenitor cells and consequently immunosuppressants are rarely required. Attempts have been made to enhance the effects of stem cells using scaffolds, trophic factors, cytokines, and other drugs in animal and/or human clinical studies. Over the past decade, several clinical trials have suggested that transplantation of MSCs into the injured spinal cord elicits therapeutic effects on SCI and is safe; however, the clinical effects are limited at present. Therefore, new therapeutic agents, such as genetically enhanced stem cells which effectively secrete neurotrophic factors or cytokines, must be developed based on the safety of pure MSCs.

Survival and Integration of Transplanted Olfactory Ensheathing Cells are Crucial for Spinal Cord Injury Repair: Insights from the Last 10 Years of Animal Model Studies

Olfactory ensheathing cells (OECs), the glial cells of the primary olfactory nervous system, support the natural regeneration of the olfactory nerve that occurs throughout life. OECs thus exhibit unique properties supporting neuronal survival and growth. Transplantation of OECs is emerging as a promising treatment for spinal cord injury; however, outcomes in both animals and humans are variable and the method needs improvement and standardization. A major reason for the discrepancy in functional outcomes is the variability in survival and integration of the transplanted cells, key factors for successful spinal cord regeneration. Here, we review the outcomes of OEC transplantation in rodent models over the last 10 years, with a focus on survival and integration of the transplanted cells. We identify the key factors influencing OEC survival: injury type, source of transplanted cells, co-transplantation with other cell types, number and concentration of cells, method of delivery, and time of transplantation after the injury. We found that two key issues are hampering optimization and standardization of OEC transplantation: lack of (1) reliable methods for identifying transplanted cells, and (2) three-dimensional systems for OEC delivery. To develop OEC transplantation as a successful and standardized therapy for spinal cord injury, we must address these issues and increase our understanding of the complex parameters influencing OEC survival.

Emerging Safety of Intramedullary Transplantation of Human Neural Stem Cells in Chronic Cervical and Thoracic Spinal Cord Injury

BACKGROUND

Human central nervous system stem cells (HuCNS-SC) are multipotent adult stem cells with successful engraftment, migration, and region-appropriate differentiation after spinal cord injury (SCI).

OBJECTIVE

To present data on the surgical safety profile and feasibility of multiple intramedullary perilesional injections of HuCNS-SC after SCI.

METHODS

Intramedullary free-hand (manual) transplantation of HuCNS-SC cells was performed in subjects with thoracic (n = 12) and cervical (n = 17) complete and sensory incomplete chronic traumatic SCI.

RESULTS

Intramedullary stem cell transplantation needle times in the thoracic cohort (20 M HuCNS-SC) were 19:30 min and total injection time was 42:15 min. The cervical cohort I (n = 6), demonstrated that escalating doses of HuCNS-SC up to 40 M range were well tolerated. In cohort II (40 M, n = 11), the intramedullary stem cell transplantation needle times and total injection time was 26:05 ± 1:08 and 58:14 ± 4:06 min, respectively. In the first year after injection, there were 4 serious adverse events in 4 of the 12 thoracic subjects and 15 serious adverse events in 9 of the 17 cervical patients. No safety concerns were considered related to the cells or the manual intramedullary injection. Cervical magnetic resonance images demonstrated mild increased T2 signal change in 8 of 17 transplanted subjects without motor decrements or emerging neuropathic pain. All T2 signal change resolved by 6 to 12 mo post-transplant.

CONCLUSION

A total cell dose of 20 M cells via 4 and up to 40 M cells via 8 perilesional intramedullary injections after thoracic and cervical SCI respectively proved safe and feasible using a manual injection technique.

Models and treatments for traumatic optic neuropathy and demyelinating optic neuritis

Pathologies of the optic nerve could result as primary insults in the visual tract or as secondary deficits due to inflammation, demyelination, or compressing effects of the surrounding tissue. The extent of damage may vary from mild to severe, differently affecting patient vision, with the most severe forms leading to complete uni- or bilateral visual loss. The aim of researchers and clinicians in the field is to alleviate the symptoms of these, yet uncurable pathologies, taking advantage of known and novel potential therapeutic approaches, alone or in combinations, and applying them in a limited time window after the insult. In this review, we discuss the epidemiological and clinical profile as well as the pathophysiological mechanisms of two main categories of optic nerve pathologies, namely traumatic optic neuropathy and optic neuritis, focusing on the demyelinating form of the latter. Moreover, we report on the main rodent models mimicking these pathologies or some of their clinical aspects. The current treatment options will also be reviewed and novel approaches will be discussed.

Stem cell/cellular interventions in human spinal cord injury: Is it time to move from guidelines to regulations and legislations? Literature review and Spinal Cord Society position statement

PURPOSE

In preclinical studies, many stem cell/cellular interventions demonstrated robust regeneration and/or repair in case of SCI and were considered a promising therapeutic candidate. However, data from clinical studies are not robust. Despite lack of substantial evidence for the efficacy of these interventions in spinal cord injury (SCI), many clinics around the world offer them as "therapy." These "clinics" claim efficacy through patient testimonials and self-advertisement without any scientific evidence to validate their claims. Thus, SCS established a panel of experts to review published preclinical studies, clinical studies and current global guidelines/regulations on usage of cellular transplants and make recommendations for their clinical use.

METHODS

The literature review and draft position statement was compiled and circulated among the panel and relevant suggestions incorporated to reach consensus. This was discussed and finalized in an open forum during the SCS Annual Meeting, ISSICON.

RESULTS

Preclinical evidence suggests safety and clinical potency of cellular interventions after SCI. However, evidence from clinical studies consisted of mostly case reports or uncontrolled case series/studies. Data from animal studies cannot be generalized to human SCI with regard to toxicity prediction after auto/allograft transplantation.

CONCLUSIONS

Currently, cellular/stem cell transplantation for human SCI is experimental and needs to be tested through a valid clinical trial program. It is not ethical to provide unproven transplantation as therapy with commercial implications. To stop the malpractice of marketing such "unproven therapies" to a vulnerable population, it is crucial that all countries unite to form common, well-defined regulations/legislation on their use in SCI. These slides can be retrieved from Electronic Supplementary Material.

Methods of olfactory ensheathing cell harvesting from the olfactory mucosa in dogs

Olfactory ensheathing cells are thought to support regeneration and remyelination of damaged axons when transplanted into spinal cord injuries. Following transplantation, improved locomotion has been detected in many laboratory models and in dogs with naturally-occurring spinal cord injury; safety trials in humans have also been completed. For widespread clinical implementation, it will be necessary to derive large numbers of these cells from an accessible and, preferably, autologous, source making olfactory mucosa a good candidate. Here, we compared the yield of olfactory ensheathing cells from the olfactory mucosa using 3 different techniques: rhinotomy, frontal sinus keyhole approach and rhinoscopy. From canine clinical cases with spinal cord injury, 27 biopsies were obtained by rhinotomy, 7 by a keyhole approach and 1 with rhinoscopy. Biopsy via rhinoscopy was also tested in 13 cadavers and 7 living normal dogs. After 21 days of cell culture, the proportions and populations of p75-positive (presumed to be olfactory ensheathing) cells obtained by the keyhole approach and rhinoscopy were similar (~4.5 x 10⁶ p75-positive cells; ~70% of the total cell population), but fewer were obtained by frontal sinus rhinotomy. Cerebrospinal fluid rhinorrhea was observed in one dog and emphysema in 3 dogs following rhinotomy. Blepharitis occurred in one dog after the keyhole approach. All three biopsy methods appear to be safe for harvesting a suitable number of olfactory ensheathing cells from the olfactory mucosa for transplantation within the spinal cord but each technique has specific advantages and drawbacks.

Application of olfactory ensheathing cells in clinical treatment of spinal cord injury: meta-analysis and prospect

Background:

A number of clinical trials of olfactory ensheathing cells (OECs) for the treatment of chronic spinal cord injury (SCI) have been carried out all over the world. However, their safety and efficacy have not been basically evaluated. Moreover, there are no uniform standards laid out for the use of optimal source, transplantation method and the dosage of OECs.

Objective:

This study evaluated the source, dose, and route of transplantation of OECs for the treatment of chronic SCI.

Methods:

PubMed, Cochrane Library, EMBASE, CNKI, and Wanfang Data were searched for the clinical studies of OECs in the treatment of chronic SCI on July 2018.

Results:

A total of 30 articles on OECs transplantation for chronic SCI were selected for comprehensive evaluation of OECs sources, doses, and transplantation methods. The efficacy of OECs in the treatment of chronic SCI was evaluated using Review Manager 5.3.

Conclusion:

Fetal OECs are the primary source of cells for the treatment of chronic SCI in OECs, with standardized cell-culture and quality-control processes. Fetal OECs can significantly improve the neurological function of patients with chronic SCI. It is an ideal cell therapy for neurorestoration. However to explore more precise and minimally invasive treatment options are required in the future.

CD34+ Stem Cell Treatment for Knee Osteoarthritis: A Treatment and Rehabilitation Algorithm

Osteoarthritis is a group of multiple overlapping pathological conditions that cause destruction of articular cartilage and other structures of the joint. It is a progressive disease that leads to limitations of physical activity. New forms of treatment are therefore sought to alleviate the clinical symptoms of osteoarthritis and avoid surgery. Stem cell based therapy is an emerging field in orthopaedics. This study describes the treatment of knee osteoarthritis with CD34+ stem cells at the Medical Magnus Outpatient Clinic in Lodz, Poland, together with the treatment and rehabilitation algorithm developed for maximum effectiveness of this procedure. The algorithm includes 3 rehabilitation stages: preoperative, hospitalization and outpatient periods.