The co-transplantation of human bone marrow stromal cells and embryo olfactory ensheathing cells as a new approach to treat spinal cord injury in a rat model

CREB1 Facilitates GABAergic Neural Differentiation of Human Mesenchymal Stem Cells through BRN2 for Pain Alleviation and Locomotion Recovery after Spinal Cord Injury

The transplantation of GABAergic neuron cells has been reported to alleviate nerve pain and improve motor function after spinal cord injury (SCI). However, human mesenchymal stem cell (hMSC) differentiation into GABAergic neuron cells in a sufficient quantity remains to be accomplished. From a database screening, cAMP-responsive element-binding protein 1 (CREB1) was chosen as a potential modulator due to its critical role in the protein-protein interaction of genes related to GABAergic neural differentiation. Here, CREB1 was overexpressed in transfected hMSCs, where CREB1 could induce differentiation into GABAergic neuron cells with an upregulation of Map2 and GAD1 by 2- and 3.4-fold, respectively. Additionally, GABAergic neural differentiation was enhanced, while Notch signaling was inhibited, and BRN2 transcriptional activation played an important role in neuronal maturation. Moreover, transfected hMSCs injected into immunocompromised mice caused by CsA exhibited the neuronal markers Tuj1 and Map2 via the intraspinal route, suggesting an improvement in survival and neural differentiation. Significantly, improvement in both BMS scores (6.2 ± 1.30 vs. 4 ± 0) and thermal hyperalgesia latency (7.74 ± 2.36 s vs. 4.52 ± 0.39 s) was seen compared with the SCI naïve treatment at 4 weeks post-transplantation. Our study demonstrates that CREB1 is crucial in generating induced GABAergic neuron cells (iGNs) originating from hMSCs. Transplanting iGNs to injured spinal cord provides a promising strategy for alleviating neuropathic pain and locomotion recovery after SCI.

Exosomes derived from olfactory ensheathing cells provided neuroprotection for spinal cord injury by switching the phenotype of macrophages/microglia

Transplantation of olfactory ensheathing cells (OECs) has been demonstrated to be beneficial for spinal cord injury (SCI) by modulating neuroinflammation, supporting neuronal survival and promoting angiogenesis. Besides OECs, the conditioned medium (CM) from OECs has also been proved to have therapeutic effects for SCI, indicating that the bioactive substances secreted by OECs are essential for its protective effects. Nevertheless, there is still little information regarding the underlying mechanisms. Considering that exosomes are crucial for intercellular communication and could be secreted by different types of cells, we speculated that the therapeutic potential of OECs for SCI might be partially based on their exosomes. To examine whether OECs could secret exosomes, we isolated exosomes by polyethylene glycol-based method, and identified them by electron microscopy study, nanoparticle tracking analysis (NTA) and western blotting. In view of phagocytic ability of microglia and its distinct roles in microenvironment regulation after SCI, we then focused the effects of OECs-derived exosomes (OECs-Exo) on microglial phenotypic regulation. We found that the extracted OECs-Exo could be engulfed by microglia and partially reverse the LPS-induced pro-inflammatory polarization through inhibiting NF-κB and c-Jun signaling pathways in vitro. Furthermore, OECs-Exo were found to inhibit the polarization of pro-inflammatory macrophages/microglia while increased the numbers of anti-inflammatory cells after SCI. Considering that the neuronal injury is closely related to the activation state of macrophages/microglia, co-culture of microglia and neurons were performed. Neuronal death induced by LPS-treated microglia could be significantly alleviated when microglia treated by LPS plus OECs-Exo in vitro. After SCI, NeuN-immunostaining and axonal tract-tracing were performed to assess neuronal survival and axon preservation. Our data showed that the OECs-Exo promoted the neuronal survival and axon preservation, and facilitated functional recovery after SCI. Our findings provide a promising therapeutic strategy for SCI based on exosome-immunomodulation.

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.

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.

Cell therapy for spinal cord injury with olfactory ensheathing glia cells (OECs)

The prospects of achieving regeneration in the central nervous system (CNS) have changed, as most recent findings indicate that several species, including humans, can produce neurons in adulthood. Studies targeting this property may be considered as potential therapeutic strategies to respond to injury or the effects of demyelinating diseases in the CNS. While CNS trauma may interrupt the axonal tracts that connect neurons with their targets, some neurons remain alive, as seen in optic nerve and spinal cord (SC) injuries (SCIs). The devastating consequences of SCIs are due to the immediate and significant disruption of the ascending and descending spinal pathways, which result in varying degrees of motor and sensory impairment. Recent therapeutic studies for SCI have focused on cell transplantation in animal models, using cells capable of inducing axon regeneration like Schwann cells (SchCs), astrocytes, genetically modified fibroblasts and olfactory ensheathing glia cells (OECs). Nevertheless, and despite the improvements in such cell-based therapeutic strategies, there is still little information regarding the mechanisms underlying the success of transplantation and regarding any secondary effects. Therefore, further studies are needed to clarify these issues. In this review, we highlight the properties of OECs that make them suitable to achieve neuroplasticity/neuroregeneration in SCI. OECs can interact with the glial scar, stimulate angiogenesis, axon outgrowth and remyelination, improving functional outcomes following lesion. Furthermore, we present evidence of the utility of cell therapy with OECs to treat SCI, both from animal models and clinical studies performed on SCI patients, providing promising results for future treatments.

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

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

Magnetic resonance imaging tracking and assessing repair function of the bone marrow mesenchymal stem cells transplantation in a rat model of spinal cord injury

The transplantation of bone marrow mesenchymal stem cells (BMSCs) to repair spinal cord injury (SCI) has become a promising therapy. However, there is still a lack of visual evidence directly implicating the transplanted cells as the source of the improvement of spinal cord function. In this study, BMSCs were labeled with NF-200 promoter and lipase-activated gadolinium-containing nanoparticles (Gd-DTPA-FA). Double labeled BMSCs were implanted into spinal cord transaction injury in rat models in situ, the function recovery was evaluated on 1st, 7th, 14th, 28 th days by MRI, Diffusion Tensor Imaing, CT imaging and post-processing, and histological observations. BBB scores were used for assessing function recovery. After transplantation of BMSCs, the hypersignal emerged in spinal cord in T1WI starting at day 7 that was focused at the injection site, which then increased and extended until day 14. Subsequently, the increased signal intensity area rapidly spread from the injection site to entire injured segment lasting four weeks. The diffusion tensor tractography and histological analysis both showed the nerve fibre from dividing to connecting partly. Immunofluorescence showed higher expression of NF-200 in Repaired group than Injury group. Electron microscopy showed detachment and loose of myelin lamellar getting better in Repaired group compared with the Injury group. BBB scores in Repaired group were significantly higher than those of injury animals. Our study suggests that the migration and distribution of Gd-DTPA-FA labeled BMSCs can be tracked using MRI. Transplantation of BMSCs represents a promising potential strategy for the repair of SCI.

Co-transplantation of autologous OM-MSCs and OM-OECs: a novel approach for spinal cord injury

Spinal cord injury (SCI) is a disastrous injury that leads to motor and sensory dysfunctions in patients. In recent years, co-transplantation has become an increasingly used therapeutic treatment for patients with SCI. Both mesenchymal stem cells (MSCs) and olfactory-ensheathing cells (OECs) have been adopted to ameliorate SCI, with promising outcomes. Remarkable effects on the rehabilitation of patients with SCI have been achieved using MSCs. Olfactory mucosa (OM) MSCs from human OM are one of the most ideal cell resources for auto-transplantation in clinical application owing to their a high proliferation rate and multipotent capability. In addition, OECs derived from OM have been used to improve functional recovery of SCI and resulted in promising functional recovery in years. Accordingly, co-transplantation of OM-MSCs coupled with OM-OECs has been adopted to improve the recovery of SCI. Here we reviewed the reported applications of OM-MSCs and OM-OECs for SCI treatment and proposed that a novel combined strategy using both autologous OM-MSCs and OM-OECs would achieve a better approach for the treatment of SCI.

The Cotransplantation of Olfactory Ensheathing Cells with Bone Marrow Mesenchymal Stem Cells Exerts Antiapoptotic Effects in Adult Rats after Spinal Cord Injury

The mechanisms behind the repairing effects of the cotransplantation of olfactory ensheathing cells (OECs) with bone marrow mesenchymal stromal cells (BMSCs) have not been fully understood. Therefore, we investigated the effects of the cotransplantation of OECs with BMSCs on antiapoptotic effects in adult rats for which the models of SCI are induced. We examined the changes in body weight, histopathological changes, apoptosis, and the expressions of apoptosis-related proteins after 14 days and 28 days after transplantation. We also assessed animal locomotion using BBB test. We found that treatment with OECs and BMSCs had a remissive effect on behavioral outcome and histopathological changes induced SCI. Furthermore, we observed the significant antiapoptotic effect on cotransplant treated group. In addition, cotransplantation of OECs with BMSCs was found to have more significant repairing effect than that of OECs or BMSCs alone. Furthermore, the recovery of hind limb could be related to antiapoptotic effect of OECs and BMSCs through downregulating the apoptotic pathways. Finally, our data suggested the cotransplantation of OECs with BMSCs holds promise for a potential cure after SCI through the ability to incorporate into the spinal cord.

Safety profile, feasibility and early clinical outcome of cotransplantation of olfactory mucosa and bone marrow stem cells in chronic spinal cord injury patients

Study Design

Prospective case series.

Purpose

To study the safety and feasibility of cotransplantation of bone marrow stem cells and autologous olfactory mucosa in chronic spinal cord injury.

Overview of Literature

Stem cell therapies are a novel method in the attempt to restitute heavily damaged tissues. We discuss our experience with this modality in postspinal cord injury paraplegics.

Methods

The study includes 9 dorsal spine injury patients with American Spinal Injury Association (ASIA) Impairment Scale (AIS) A neurological impairment who underwent de-tethering of the spinal cord followed by cotransplantation with bone marrow stem cells and an olfactory mucosal graft. Participants were evaluated at the baseline and at 6 monthly intervals. Safety and tolerability were evaluated through the monitoring for adverse events and magnetic resonance imaging evaluation. Efficacy assessment was done through neurological and functional outcome measures.

Results

Surgery was tolerated well by all participants. No significant difference in the ASIA score was observed, although differences in the Functional Independence Measure and Modified Ashworth Scale were statistically significant. No significant complication was observed in any of our patients, except for neurogenic pain in one participant. The follow-up magnetic resonance imaging evaluation revealed an increase in the length of myelomalacia in seven participants.

Conclusions

The cotransplantation of bone marrow stem cells and olfactory mucosa is a safe, feasible and viable procedure in AIS A participants with thoracic level injuries, as assessed at the 24-month follow-up. No efficacy could be demonstrated. For application, further large-scale multicenter studies are needed.

From basics to clinical: a comprehensive review on spinal cord injury

Spinal cord injury (SCI) is a devastating neurological disorder that affects thousands of individuals each year. Over the past decades an enormous progress has been made in our understanding of the molecular and cellular events generated by SCI, providing insights into crucial mechanisms that contribute to tissue damage and regenerative failure of injured neurons. Current treatment options for SCI include the use of high dose methylprednisolone, surgical interventions to stabilize and decompress the spinal cord, and rehabilitative care. Nonetheless, SCI is still a harmful condition for which there is yet no cure. Cellular, molecular, rehabilitative training and combinatorial therapies have shown promising results in animal models. Nevertheless, work remains to be done to ascertain whether any of these therapies can safely improve patient's condition after human SCI. This review provides an extensive overview of SCI research, as well as its clinical component. It starts covering areas from physiology and anatomy of the spinal cord, neuropathology of the SCI, current clinical options, neuronal plasticity after SCI, animal models and techniques to assess recovery, focusing the subsequent discussion on a variety of promising neuroprotective, cell-based and combinatorial therapeutic approaches that have recently moved, or are close, to clinical testing.

Preliminary report of multiple cell therapy for patients with multiple system atrophy

The aim of this study is to explore the safety and therapeutic effect of multiple cell transplantations on patients with multiple system atrophy. Ten patients suffering from multiple system atrophy were treated by multiple cell transplantations from August 2005 to March 2011. They were six males and four females, with an average age of 51.90 ± 12.92 years (23-66 years). Multiple cell types were transplanted by intravenous, intrathecal, and intracranial routes; for example, 0.4-0.5 × 10(6)/kg umbilical cord mesenchymal cells by intravenous drip, intrathecal implantation of 2.0 × 10(6) Schwann cells and 2.0-5.0 × 10(6) neural progenitor cells through cerebellar cistern puncture, or 2 × 10(6) olfactory ensheathing cells and 4 × 10(6) neural progenitor cells injected into key points for neural network restoration (KPNNR). The neurological function was assessed before and after treatment with the International Cooperative Ataxia Rating Scale (ICARS) by the World Federation of Neurology and the Unified Multiple System Atrophy Rating Scale (UMSARS). The patients achieved neurological function amelioration after treatment, which included improvements in walking ability, gaits, standing, speech, and muscular tension; the ICARS score decreased from a preoperative 46.30 ± 14.50 points to postoperative 41.90 ± 18.40 points (p = 0.049). The UMSARS score decreased from preoperative 50.00 ± 20.65 points to postoperative 46.56 ± 23.05 points (p = 0.037). Among them, two patients remained stable and underwent a second treatment 0.5-1 year after the first therapy. After treatment, five patients were followed up for more than 6 months. Balance and walking ability improved further in four patients, while one patient remained stable for over 6 months. In conclusion, a strategy of comprehensive cell-based neurorestorative therapy for patients with multiple system atrophy is safe and appears to be beneficial. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.

Human mesenchymal stem cells isolated from olfactory biopsies but not bone enhance CNS myelination in vitro

Spinal cord injury (SCI) is a devastating condition with limited capacity for repair. Cell transplantation is a potential strategy to promote SCI repair with cells from the olfactory system being promising candidates. Although transplants of human olfactory mucosa (OM) are already ongoing in clinical trials, the repair potential of this tissue remains unclear. Previously, we identified mesenchymal-like stem cells that reside in the lamina propria (LP-MSCs) of rat and human OM. Little is known about these cells or their interactions with glia such as olfactory ensheathing cells (OECs), which would be co-transplanted with MSCs from the OM, or endogenous CNS glia such as oligodendrocytes. We have characterized, purified, and assessed the repair potential of human LP-MSCs by investigating their effect on glial cell biology with specific emphasis on CNS myelination in vitro. Purified LP-MSCs expressed typical bone marrow MSC (BM-MSC) markers, formed spheres, were clonogenic and differentiated into bone and fat. LP-MSC conditioned medium (CM) promoted oligodendrocyte precursor cell (OPC) and OEC proliferation and induced a highly branched morphology. LP-MSC-CM treatment caused OEC process extension. Both LP and BM-MSCs promoted OPC proliferation and differentiation, but only myelinating cultures treated with CM from LP and not BM-MSCs had a significant increase in myelination. Comparison with fibroblasts and contaminating OM fibroblast like-cells showed the promyelination effect was LP-MSC specific. Thus LP-MSCs harvested from human OM biopsies may be an important candidate for cell transplantation by contributing to the repair of SCI.

The potential for cellular therapy combined with growth factors in spinal cord injury

Any traumatic spinal cord injury (SCI) may cause symptoms ranging from pain to complete loss of motor and sensory functions below the level of the injury. Currently, there are over 2 million SCI patients worldwide. The cost of their necessary continuing care creates a burden for the patient, their families, and society. Presently, few SCI treatments are available and none have facilitated neural regeneration and/or significant functional improvement. Research is being conducted in the following areas: pathophysiology, cellular therapies (Schwann cells, embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, olfactory ensheathing cells), growth factors (BDNF), inhibitory molecules (NG2, myelin protein), and combination therapies (cell grafts and neurotrophins, cotransplantation). Results are often limited because of the inhibitory environment created following the injury and the limited regenerative potential of the central nervous system. Therapies that show promise in small animal models may not transfer to nonhuman primates and humans. None of the research has resulted in remarkable improvement, but many areas show promise. Studies have suggested that a combination of therapies may enhance results and may be more effective than a single therapy. This paper reviews and discusses the most promising new SCI research including combination therapies.

Stem cell-based therapy for spinal cord injury

Stem cells (SCs) represent a new therapeutic approach for spinal cord injury (SCI) by enabling improved sensory and motor functions in animal models. The main goal of SC-based therapy for SCI is the replacement of neurons and glial cells that undergo cell death soon after injury. Stem cells are able to promote remyelination via oligodendroglia cell replacement to produce trophic factors enhancing neurite outgrowth, axonal elongation, and fiber density and to activate resident or transplanted progenitor cells across the lesion cavity. While several SC transplantation strategies have shown promising yet partial efficacy, mechanistic proof is generally lacking and is arguably the largest impediment toward faster progress and clinical application. The main challenge ahead is to spur on cooperation between clinicians, researchers, and patients in order to define and optimize the mechanisms of SC function and to establish the ideal source/s of SCs that produce efficient and also safe therapeutic approaches.

Translational neuromodulation: approximating human transcranial magnetic stimulation protocols in rats

OBJECTIVE

Transcranial magnetic stimulation (TMS) is a well-established clinical protocol with numerous potential therapeutic and diagnostic applications. Yet, much work remains in the elucidation of TMS mechanisms, optimization of protocols, and in development of novel therapeutic applications. As with many technologies, the key to these issues lies in the proper experimentation and translation of TMS methods to animal models, among which rat models have proven popular. A significant increase in the number of rat TMS publications has necessitated analysis of their relevance to human work. We therefore review the essential principles for the approximation of human TMS protocols in rats as well as specific methods that addressed these issues in published studies.

MATERIALS AND METHODS

We performed an English language literature search combined with our own experience and data. We address issues that we see as important in the translation of human TMS methods to rat models and provide a summary of key accomplishments in these areas.

RESULTS

  An extensive literature review illustrated the growth of rodent TMS studies in recent years. Current advances in the translation of single, paired-pulse, and repetitive stimulation paradigms to rodent models are presented. The importance of TMS in the generation of data for preclinical trials is also highlighted.

CONCLUSIONS

Rat TMS has several limitations when considering parallels between animal and human stimulation. However, it has proven to be a useful tool in the field of translational brain stimulation and will likely continue to aid in the design and implementation of stimulation protocols for therapeutic and diagnostic applications.

Cotransplantation of Human Embryonic Stem Cell-Derived Neural Progenitors and Schwann Cells in a Rat Spinal Cord Contusion Injury Model Elicits a Distinct Neurogenesis and Functional Recovery

Cotransplantation of neural progenitors (NPs) with Schwann cells (SCs) might be a way to overcome low rate of neuronal differentiation of NPs following transplantation in spinal cord injury (SCI) and the improvement of locomotor recovery. In this study, we initially generated NPs from human embryonic stem cells (hESCs) and investigated their potential for neuronal differentiation and functional recovery when cocultured with SCs in vitro and cotransplanted in a rat acute model of contused SCI. Cocultivation results revealed that the presence of SCs provided a consistent status for hESC-NPs and recharged their neural differentiation toward a predominantly neuronal fate. Following transplantation, a significant functional recovery was observed in all engrafted groups (NPs, SCs, NPs + SCs) relative to the vehicle and control groups. We also observed that animals receiving cotransplants established a better state as assessed with the BBB functional test. Immunohistofluorescence evaluation 5 weeks after transplantation showed invigorated neuronal differentiation and limited proliferation in the cotransplanted group when compared to the individual hESC-NP-grafted group. These findings have demonstrated that the cotransplantation of SCs with hESC-NPs could offer a synergistic effect, promoting neuronal differentiation and functional recovery.

Evaluation of cell tracking effects for transplanted mesenchymal stem cells with jetPEI/Gd-DTPA complexes in animal models of hemorrhagic spinal cord injury

Cell tracking using iron oxide nanoparticles has been well established in MRI. However, in experimental rat models, the intrinsic iron signal derived from erythrocytes masks the labeled cells. The research evaluated a clinically applied Gd-DTPA for T1-weighted positive enhancement for cell tracking in spinal cord injury (SCI) rat models. MSCs were labeled with jetPEI/Gd-DTPA particles to evaluate the transfection efficiency by MRI in vitro. Differentiation assays were carried out to evaluate the differentiation ability of Gd-DTPA-labeled MSCs. The Gd-DTPA-labeled MSCs were transplanted to rat SCI model and monitored by MRI in vivo. Fluorescence images were taken to confirm the MRI results. Behavior test was assessed with Basso, Beattie, and Bresnahan (BBB) scoring in 6weeks after cell transplantation. The Gd-labeled MSCs showed a significant increase in signal intensity in T1-weighted images. After local transplantation, Gd-DTPA-labeled MSCs could be detected in SCI rat models by the persistent T1-weighted positive enhancement from 3 to 14days. Under electronic microscope, Gd-DTPA/jetPEI complexes were mostly observed in cytoplasm. Fluorescence microscopy examination showed that the Gd-labeled MSCs survived and distributed within the injured spinal cord until 2weeks. The Gd-labeled MSCs were identified and tracked with MRI by cross and sagittal sections. The BBB scores of the rats with labeled MSCs transplantation were significantly higher than those of control rats. Our results demonstrated that Gd-DTPA is appropriate for cell tracking in rat model of SCI, indicating that an efficient and nontoxic label method with Gd-DTPA could properly track MSCs in hemorrhage animal models.

Effects of fibroblasts derived from the olfactory bulb and nasal olfactory mucosa on proliferation of olfactory ensheathing cells harvested from the olfactory bulb

Olfactory ensheathing cells (OECs) have been reported to promote axonal regeneration when transplanted to rodent spinal cord injury models. OECs are available from the olfactory bulb (OB) and olfactory mucosa (OM). Although harvesting OECs from the OM is less traumatic, OECs originating from the OM are less proliferative than those from the OB (OB-OECs). One possible reason for this difference is coexisting fibroblasts. Here, we examined the effect of coculturing either fibroblasts from the OB (OB-Fibs) or fibroblasts from the OM (OM-Fibs) on the proliferation of OB-OECs. Proliferation of OB-OECs was significantly higher in 5:5 coculture with OB-Fibs and in 7:3 and 5:5 cocultures with OM-Fibs than without fibroblasts. These results indicated that coculture with both OB-Fibs and OM-Fibs promoted the proliferation of OB-OECs.

Stem cells for spinal cord regeneration: Current status

Background:

Nearly 11,000 cases of spinal cord injury (SCI) are reported in the United States annually. Current management options give a median survival time of 38 years; however, no rehabilitative measures are available. Stem cells have been under constant research given their ability to differentiate into neural cell lines replacing non functional tissue. Efforts have been made to establish new synapses and provide a conducive environment, by grafting cells from autologous and fetal sources; including embryonic or adult stem cells, Schwann cells, genetically modified fibroblasts, bone stromal cells, and olfactory ensheathing cells and combinations/ variants thereof.

Methods:

In order to discuss the underlying mechanism of SCI along with the previously mentioned sources of stem cells in context to SCI, a simple review of literature was conducted. An extensive literature search was conducted using the PubMed data base and online search engines and articles published in the last 15 years were considered along with some historical articles where a background was required.

Results:

Stem cell transplantation for SCI is at the forefront with animal and in vitro studies providing a solid platform to enable well-designed human studies. Olfactory ensheathing cells seem to be the most promising; whilst bone marrow stromal cells appear as strong candidates for an adjunctive role.

Conclusion:

The key strategy in developing the therapeutic basis of stem cell transplantation for spinal cord regeneration is to weed out the pseudo-science and opportunism. All the trials should be based on stringent scientific criteria and effort to bypass that should be strongly discouraged at the international level.

Ex vivo-expanded autologous bone marrow-derived mesenchymal stromal cells in human spinal cord injury/paraplegia: a pilot clinical study

BACKGROUND AIMS

Spinal cord injury (SCI) is a medically untreatable condition for which stem cells have created hope in the last few years. Earlier pre-clinical reports have shown that transplantation of bone marrow (BM) mesenchymal stromal cells (MSC) in SCI-simulated models can produce encouraging results. In a clinical pilot study, we investigated the growth kinetics of BM MSC from SCI patients, their safety and functional improvement post-transplantation.

METHODS

Thirty patients with clinically complete SCI at cervical or thoracic levels were recruited and divided into two groups based on the duration of injury. Patients with <6 months of post-SCI were recruited into group 1 and patients with >6 months of post-SCI were included into group 2. Autologous BM was harvested from the iliac crest of SCI patients under local anesthesia and BM MSC were isolated and expanded ex vivo. BM MSC were tested for quality control, characterized for cell surface markers and transplanted back to the patient via lumbar puncture at a dose of 1 x 10(6) cells/kg body weight.

RESULTS

At the time of writing, three patients had completed 3 years of follow-up post-BM MSC administration, 10 patients 2 years follow-up and 10 patients 1 year follow-up. Five patients have been lost to follow-up. None of the patients have reported any adverse events associated with BM MSC transplantation.

CONCLUSIONS

The results indicate that our protocol is safe with no serious adverse events following transplantation in SCI patients. The number of patients recruited and the uncontrolled nature of the trial do not permit demonstration of the effectiveness of the treatment involved. However, the results encourage further trials with higher doses and different routes of administration in order to demonstrate the recovery/efficacy if any, in SCI patients.

A systematic review of cellular transplantation therapies for spinal cord injury

Cell transplantation therapies have become a major focus in pre-clinical research as a promising strategy for the treatment of spinal cord injury (SCI). In this article, we systematically review the available pre-clinical literature on the most commonly used cell types in order to assess the body of evidence that may support their translation to human SCI patients. These cell types include Schwann cells, olfactory ensheathing glial cells, embryonic and adult neural stem/progenitor cells, fate-restricted neural/glial precursor cells, and bone-marrow stromal cells. Studies were included for review only if they described the transplantation of the cell substrate into an in-vivo model of traumatic SCI, induced either bluntly or sharply. Using these inclusion criteria, 162 studies were identified and reviewed in detail, emphasizing their behavioral effects (although not limiting the scope of the discussion to behavioral effects alone). Significant differences between cells of the same "type" exist based on the species and age of donor, as well as culture conditions and mode of delivery. Many of these studies used cell transplantations in combination with other strategies. The systematic review makes it very apparent that cells derived from rodent sources have been the most extensively studied, while only 19 studies reported the transplantation of human cells, nine of which utilized bone-marrow stromal cells. Similarly, the vast majority of studies have been conducted in rodent models of injury, and few studies have investigated cell transplantation in larger mammals or primates. With respect to the timing of intervention, nearly all of the studies reviewed were conducted with transplantations occurring subacutely and acutely, while chronic treatments were rare and often failed to yield functional benefits.