Protection of corticospinal tract neurons after dorsal spinal cord transection and engraftment of olfactory ensheathing cells

Melatonin Enhances Neural Differentiation of Adipose-Derived Mesenchymal Stem Cells

Adipose-derived mesenchymal stem cells (ASCs) are adult multipotent stem cells, able to differentiate toward neural elements other than cells of mesodermal lineage. The aim of this research was to test ASC neural differentiation using melatonin combined with conditioned media (CM) from glial cells. Isolated from the lipoaspirate of healthy donors, ASCs were expanded in a basal growth medium before undergoing neural differentiation procedures. For this purpose, CM obtained from olfactory ensheathing cells and from Schwann cells were used. In some samples, 1 µM of melatonin was added. After 1 and 7 days of culture, cells were studied using immunocytochemistry and flow cytometry to evaluate neural marker expression (Nestin, MAP2, Synapsin I, GFAP) under different conditions. The results confirmed that a successful neural differentiation was achieved by glial CM, whereas the addition of melatonin alone did not induce appreciable changes. When melatonin was combined with CM, ASC neural differentiation was enhanced, as demonstrated by a further improvement of neuronal marker expression, whereas glial differentiation was attenuated. A dynamic modulation was also observed, testing the expression of melatonin receptors. In conclusion, our data suggest that melatonin's neurogenic differentiation ability can be usefully exploited to obtain neuronal-like differentiated ASCs for potential therapeutic strategies.

MicroRNA-133b Dysregulation in a Mouse Model of Cervical Contusion Injury

Our previous research studies have demonstrated the role of microRNA133b (miR133b) in healing the contused spinal cord when administered either intranasally or intravenously 24 h following an injury. While our data showed beneficial effects of exogenous miR133b delivered within hours of a spinal cord injury (SCI), the kinetics of endogenous miR133b levels in the contused spinal cord and rostral/caudal segments of the injury were not fully investigated. In this study, we examined the miR133b dysregulation in a mouse model of moderate unilateral contusion injury at the fifth cervical (C5) level. Between 30 min and 7 days post-injury, mice were euthanized and tissues were collected from different areas of the spinal cord, ipsilateral and contralateral prefrontal motor cortices, and off-targets such as lung and spleen. The endogenous level of miR133b was determined by RT-qPCR. We found that after SCI, (a) most changes in miR133b level were restricted to the injured area with very limited alterations in the rostral and caudal parts relative to the injury site, (b) acute changes in the endogenous levels were predominantly specific to the lesion site with delayed miR133b changes in the motor cortex, and (c) ipsilateral and contralateral hemispheres responded differently to unilateral SCI. Our results suggest that the therapeutic window for exogenous miR133b therapy begins earlier than 24 h post-injury and potentially lasts longer than 7 days.

Electrical stimulation promotes functional recovery after spinal cord injury by activating endogenous spinal cord-derived neural stem/progenitor cell: an in vitro and in vivo study

BACKGROUND CONTEXT

Electrical stimulation is a noninvasive treatment method that has gained popularity in the treatment of spinal cord injury (SCI). Activation of spinal cord-derived neural stem/progenitor cell (SC-NSPC) proliferation and differentiation in the injured spinal cord may elicit considerable neural regenerative effects.

PURPOSE

This study aimed to explore the effect of electrical stimulation on the neurogenesis of SC-NSPCs.

STUDY DESIGN

This study analyzed the effects of electrical stimulation on neurogenesis in rodent SC-NSPCs in vitro and in vivo and evaluated functional recovery and neural circuitry improvements with electrical stimulation using a rodent SCI model.

METHODS

Rats (20 rats/group) were assigned to sham (Group 1), SCI only (Group 2), SCI + electrode implant without stimulation (Group 3), and SCI + electrode with stimulation (Group 4) groups to count total SC-NSPCs and differentiated neurons and to evaluate morphological changes in differentiated neurons. Furthermore, the Basso, Beattie, and Bresnahan scores were analyzed, and the motor- and somatosensory-evoked potentials in all rats were monitored.

RESULTS

Biphasic electrical currents enhanced SC-NSPC proliferation differentiation and caused qualitative morphological changes in differentiated neurons in vitro. Electrical stimulation promoted SC-NSPC proliferation and neuronal differentiation and improved functional outcomes and neural circuitry in SCI models. Increased Wnt3, Wnt7, and β-catenin protein levels were also observed after electrical stimulation.

CONCLUSIONS

Our study proved the beneficial effects of electrical stimulation on SCI. The Wnt/β-catenin pathway activation may be associated with this relationship between electrical stimulation and neuronal regeneration after SCI.

CLINICAL SIGNIFICANCE

The study confirmed the benefits of electrical stimulation on SCI based on cellular, functional, electrophysiological, and histological evidence. Based on these findings, we expect electrical stimulation to make a positive and significant difference in SCI treatment strategies.

Role of curcumin and its nanoformulations in the treatment of neurological diseases through the effects on stem cells

Curcumin from turmeric is a natural phenolic compound with a promising potential to regulate fundamental processes involved in neurological diseases, including inflammation, oxidative stress, protein aggregation, and apoptosis at the molecular level. In this regard, employing nanoformulation can improve curcumin efficiency by reducing its limitations, such as low bioavailability. Besides curcumin, growing data suggest that stem cells are a noteworthy candidate for neurodegenerative disorders therapy due to their anti-inflammatory, anti-oxidative, and neuronal-differentiation properties, which result in neuroprotection. Curcumin and stem cells have similar neurogenic features and can be co-administered in a cell-drug delivery system to achieve better combination therapeutic outcomes for neurological diseases. Based on the evidence, curcumin can induce the neuroprotective activity of stem cells by modulating their related signalling pathways. The present review is about the role of curcumin and its nanoformulations in the improvement of neurological diseases alone and through the effect on different categories of stem cells by discussing the underlying mechanisms to provide a roadmap for future investigations.

The Anti-inflammation Property of Olfactory Ensheathing Cells in Neural Regeneration After Spinal Cord Injury

Neural regeneration has troubled investigators worldwide in the past decades. Currently, cell transplantation emerged as a breakthrough targeted therapy for spinal cord injury (SCI) in the neurotrauma field, which provides a promising strategy in neural regeneration. Olfactory ensheathing cells (OECs), a specialized type of glial cells, is considered as the excellent candidate due to its unique variable and intrinsic regeneration-supportive properties. In fact, OECs could support olfactory receptor neuron turnover and axonal extension, which is essential to maintain the function of olfactory nervous system. Hitherto, an increasing number of literatures demonstrate that transplantation of OECs exerts vital roles in neural regeneration and functional recovery after neural injury, including central and peripheral nervous system. It is common knowledge that the deteriorating microenvironment (ischemia, hypoxia, scar, acute and chronic inflammation, etc.) resulting from injured nervous system is adverse for neural regeneration. Interestingly, recent studies indicated that OECs could promote neural repair through improvement of the disastrous microenvironments, especially to the overwhelmed inflammatory responses. Although OECs possess unusual advantages over other cells for neural repair, particularly in SCI, the mechanisms of OEC-mediated neural repair are still controversial with regard to anti-inflammation. Therefore, it is significant to summarize the anti-inflammation property of OECs, which is helpful to understand the biological characteristics of OECs and drive future studies. Here, we mainly focus on the anti-inflammatory role of OECs to make systematic review and discuss OEC-based therapy for CNS injury.

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.

Research progress and prospects of tissue engineering scaffolds for spinal cord injury repair and protection

Spinal cord injury (SCI) is one of the leading causes of global disability. However, there are currently no effective clinical treatments for SCI. Repair of SCI is essential but poses great challenges. As a comprehensive treatment program combining biological scaffolds, seed cells and drugs or biological factors, tissue engineering has gradually replaced the single transplantation approach to become a focus of research that brings new opportunities for the clinical treatment of SCI.

Comprehensive therapeutics targeting the corticospinal tract following spinal cord injury

Spinal cord injury (SCI), which is much in the public eye, is still a refractory disease compromising the well-being of both patients and society. In spite of there being many methods dealing with the lesion, there is still a deficiency in comprehensive strategies covering all facets of this damage. Further, we should also mention the structure called the corticospinal tract (CST) which plays a crucial role in the motor responses of organisms, and it will be the focal point of our attention. In this review, we discuss a variety of strategies targeting different dimensions following SCI and some treatments that are especially efficacious to the CST are emphasized. Over recent decades, researchers have developed many effective tactics involving five approaches: (1) tackle more extensive regions; (2) provide a regenerative microenvironment; (3) provide a glial microenvironment; (4) transplantation; and (5) other auxiliary methods, for instance, rehabilitation training and electrical stimulation. We review the basic knowledge on this disease and correlative treatments. In addition, some well-formulated perspectives and hypotheses have been delineated. We emphasize that such a multifaceted problem needs combinatorial approaches, and we analyze some discrepancies in past studies. Finally, for the future, we present numerous brand-new latent tactics which have great promise for curbing SCI.

Functional Consequences of Keratan Sulfate Sulfation in Electrosensory Tissues and in Neuronal Regulation

Keratan sulfate (KS) is a functional electrosensory and neuro-instructive molecule. Recent studies have identified novel low sulfation KS in auditory and sensory tissues such as the tectorial membrane of the organ of Corti and the Ampullae of Lorenzini in elasmobranch fish. These are extremely sensitive proton gradient detection systems that send signals to neural interfaces to facilitate audition and electrolocation. High and low sulfation KS have differential functional roles in song learning in the immature male zebra song-finch with high charge density KS in song nuclei promoting brain development and cognitive learning. The conductive properties of KS are relevant to the excitable neural phenotype. High sulfation KS interacts with a large number of guidance and neuroregulatory proteins. The KS proteoglycan microtubule associated protein-1B (MAP1B) stabilizes actin and tubulin cytoskeletal development during neuritogenesis. A second 12 span transmembrane synaptic vesicle associated KS proteoglycan (SV2) provides a smart gel storage matrix for the storage of neurotransmitters. MAP1B and SV2 have prominent roles to play in neuroregulation. Aggrecan and phosphacan have roles in perineuronal net formation and in neuroregulation. A greater understanding of the biology of KS may be insightful as to how neural repair might be improved.

Transplantation of cultured olfactory mucosal cells rescues optic nerve axons in a rat glaucoma model

PURPOSE

To determine whether transplantation of olfactory mucosal cells (OMCs) is able to rescue the loss of optic nerve axons after the intraocular pressure (IOP) is elevated in rats.

METHODS

The IOP was raised by injection of magnetic microspheres into the anterior chamber of the eye. OMCs cultured from the adult olfactory mucosa were transplanted into the region of the optic disc.

RESULTS

We demonstrated that although the raised IOP returned to its normal level at six weeks, there was an irreversible 58% loss of optic nerve axons in the control group. However, the loss of the axons was reduced to 23% in the group with the transplanted OMCs. The Pattern Electroretinograms (pERG) showed that the decrement of the voltage amplitudes in association with the raised IOP was significantly alleviated in the group with transplantation of OMC.

CONCLUSIONS

Transplantation of OMCs is able to rescue loss of optic nerve axons induced by raised IOP in the rats. The pERG recording suggested that the functional activities of the axons are also protected.

TRANSLATIONAL RELEVANCE

The results demonstrated the ability of the transplanted OMCs to protect against the loss of the optic nerve axons and the loss of function caused by raised IOPs. The findings provide a basis for future human clinical trials by autografting OMCs from autologous nasal epithelial biopsies to treat or delay glaucoma diseases.

Olfactory Ensheathing Cells for Spinal Cord Injury: Sniffing Out the Issues

Olfactory ensheathing cells (OECs) are glia reported to sustain the continuous axon extension and successful topographic targeting of the olfactory receptor neurons responsible for the sense of smell (olfaction). Due to this distinctive property, OECs have been trialed in human cell transplant therapies to assist in the repair of central nervous system injuries, particularly those of the spinal cord. Though many studies have reported neurological improvement, the therapy remains inconsistent and requires further improvement. Much of this variability stems from differing olfactory cell populations prior to transplantation into the injury site. While some studies have used purified cells, others have used unpurified transplants. Although both preparations have merits and faults, the latter increases the variability between transplants received by recipients. Without a robust purification procedure in OEC transplantation therapies, the full potential of OECs for spinal cord injury may not be realised.

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.

Biomaterial-Supported Cell Transplantation Treatments for Spinal Cord Injury: Challenges and Perspectives

Spinal cord injury (SCI), resulting in para- and tetraplegia caused by the partial or complete disruption of descending motor and ascending sensory neurons, represents a complex neurological condition that remains incurable. Following SCI, numerous obstacles comprising of the loss of neural tissue (neurons, astrocytes, and oligodendrocytes), formation of a cavity, inflammation, loss of neuronal circuitry and function must be overcome. Given the multifaceted primary and secondary injury events that occur with SCI treatment options are likely to require combinatorial therapies. While several methods have been explored, only the intersection of two, cell transplantation and biomaterial implantation, will be addressed in detail here. Owing to the constant advance of cell culture technologies, cell-based transplantation has come to the forefront of SCI treatment in order to replace/protect damaged tissue and provide physical as well as trophic support for axonal regrowth. Biomaterial scaffolds provide cells with a protected environment from the surrounding lesion, in addition to bridging extensive damage and providing physical and directional support for axonal regrowth. Moreover, in this combinatorial approach cell transplantation improves scaffold integration and therefore regenerative growth potential. Here, we review the advances in combinatorial therapies of Schwann cells (SCs), astrocytes, olfactory ensheathing cells (OECs), mesenchymal stem cells, as well as neural stem and progenitor cells (NSPCs) with various biomaterial scaffolds.

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.

Phenotypic Modulation and Neuroprotective Effects of Olfactory Ensheathing Cells: a Promising Tool for Cell Therapy

Olfactory Ensheathing Cells (OECs), exhibiting phenotypic characteristics of both astrocytes and Schwann Cells, show peculiar plasticity. In vitro, OECs promote axonal growth, while in vivo they promote remyelination of damaged axons. We decided to further investigate OEC potential for regeneration and functional recovery of the damaged Central Nervous System (CNS). To study OEC antigen modulation, OECs prepared from postnatal mouse olfactory bulbs were grown in different culture conditions: standard or serum-free media with/without Growth Factors (GFs) and analyzed for different neural specific markers. OEC functional characterizations were also achieved. Resistance of OECs to the neurotoxin 6-hydroxydopamine (6-OHDA) was analyzed by evaluating apoptosis and death. OEC neuroprotective properties were investigated by in vitro co-cultures or by addition of OEC conditioned medium to the neuroblastoma SH-SY5Y cells exposed to 6-OHDA. We observed: 1) modification of OEC morphology, reduced cell survival and marker expression in serum-free medium; 2) GF addition to serum-free medium condition influenced positively survival and restored basal marker expression; 3) no OEC apoptosis after a prolonged exposition to 6-OHDA; 4) a clear OEC neuroprotective tendency, albeit non statistically significant, on 6-OHDA treated SH-SY5Y cells. These peculiar properties of OECs might render them potential clinical agents able to support injured CNS.

Antioxidant and Anti-Senescence Effect of Metformin on Mouse Olfactory Ensheathing Cells (mOECs) May Be Associated with Increased Brain-Derived Neurotrophic Factor Levels-An Ex Vivo Study

Metformin, the popular anti-diabetic drug was shown to exert multiple biological effects. The most recent metformin gained attention as an agent that mobilizes endogenous progenitor cells and enhances regenerative potential of organisms, for example by promoting neurogenesis. In the present study, we examined the role of metformin on mouse olfactory ensheathing cells (mOECs) derived from animals receiving metformin for eight weeks at a concentration equal to 2.8 mg/day. The mOECs expanded ex vivo were characterized in terms of their cellular phenotype, morphology, proliferative activity, viability and accumulation of oxidative stress factors. Moreover, we determined the mRNA and protein levels of brain-derived neurotrophic factor (BDNF), distinguishing the secretion of BDNF by mOECs in cultures and circulating serum levels of BDNF. The mOECs used in the experiment were glial fibrillary acidic protein (GFAP) and p75 neurotrophin receptor (p75^NTR) positive and exhibited both astrocyte-like and non-myelin Schwann cell-like morphologies. Our results revealed that the proliferation of OECs derived from mice treated with metformin was lowered, when compared to control group. Simultaneously, we noted increased cell viability, reduced expression of markers associated with cellular senescence and a decreased amount of reactive oxygen species. We observed increased mRNA expression of BDNF and its down-stream genes. Obtained results indicate that metformin may exert antioxidant, anti-apoptotic and senolytic action on OECs expanded ex vivo.

Synergistic effect of olfactory ensheathing cells and alpha-crystallin on restoration of adult rat optic nerve injury

Olfactory enshesathing cells (OECs) and α-crystallin all can promote axonal regeneration after optic nerve injury. However, their mechanisms were different. Here, we study the synergistic effect of OECs and α-crystallin on the optic nerve regeneration. α-Crystallin was injected into vitreous cavity, and OECs were transplanted to the optic nerve injury area. The regeneration length of optic nerve were measured by anterograde tracing using cholera toxin subunit B (CTB). The survival of RGCs were assessed by counting the numbers of βIII-tubulin-labeled RGCs in a retinal whole mount. The results that OECs and α-crystallin all could promoted RGCs survival and axonal regeneration (P<0.01). Especially in the combination group, the length of axonal regeneration was 5.6mm after optic nerve injury for 3 months. These findings indicated that compared to OECs and α-crystallin alone, the combination of OECs and α-crystallin could promote axonal regeneration more effectively.

TWEAK-Fn14 Influences Neurogenesis Status via Modulating NF-κB in Mice with Spinal Cord Injury

The aim of our research is to investigate the regulatory role of TNF-like weak inducer of apoptosis- fibroblast growth factor-inducible 14 (TWEAK-Fn14) pathway in nuclear factor-kappa B (NF-κB) expression and neurogenesis status after spinal cord injury (SCI). We constructed a mice model of spinal cord injury and injected different lentiviral vectors which were transfected with TWEAK, TWEAK small interfering RNA (siRNA) and Fn14 siRNA into different groups of mice. Locomotor functional recovery status of the hind limb in mice was assessed using the Basso, Beattie and Bresnahan (BBB) test. Apoptosis status in the injured area was examined via TDT-mediated dUTP-biotin nick end-labeling (TUNEL) staining, the expression of GAP-43 in injured spinal cord was quantified by immunohistochemistry and expressions of TWEAK, Fn14, NF-κB, TNF-α, and IL-1β were evaluated by either western blot or ELISA. The expressions of TWEAK, Fn14, and NF-κB in the model group were significantly higher compared with those in the control group. Furthermore, the TWEAK group in which TWEAK was overexpressed exhibited significantly higher expressions of TWEAK, Fn14, and NF-κB, TNF-α and IL-1β in relation to those in the model group (P < 0.05 for all). Moreover, the transfection of Fn14 siRNA antagonized the above effect of TWEAK transfection on injured mice. On the other hand, the TWEAK siRNA group in which the expression of TWEAK was inhibited exhibited significantly lower expressions of TWEAK, Fn14, NF-κB, TNF-α, and IL-1β (P < 0.05 for all). Moreover, the transfection of TWEAK siRNA enhanced the locomotor functional recovery status in injured mice and suppressed the apoptosis of injured areas (P < 0.05 for all). In conclusion, stimulating the TWEAK-Fn14 pathway may elevate the expression of NF-κB, thereby slow the function recovery of SCI mice whereas inhibiting the TWEAK-Fn14 pathway may improve the neurogenesis status in mice with spinal cord injuries.

Brain-derived Neurotrophic Factor Promotes the Migration of Olfactory Ensheathing Cells Through TRPC Channels

Olfactory ensheathing cells (OECs) are a unique type of glial cells with axonal growth-promoting properties in the olfactory system. Organized migration of OECs is essential for neural regeneration and olfactory development. However, the molecular mechanism of OEC migration remains unclear. In the present study, we examined the effects of brain-derived neurotrophic factor (BDNF) on OEC migration. Initially, the "scratch" migration assay, the inverted coverslip and Boyden chamber migration assays showed that BDNF could promote the migration of primary cultured OECs. Furthermore, BDNF gradient attracted the migration of OECs in single-cell migration assays. Mechanistically, TrkB receptor expressed in OECs mediated BDNF-induced OEC migration, and BDNF triggered calcium signals in OECs. Finally, transient receptor potential cation channels (TRPCs) highly expressed in OECs were responsible for BDNF-induced calcium signals, and required for BDNF-induced OEC migration. Taken together, these results demonstrate that BDNF promotes the migration of cultured OECs and an unexpected finding is that TRPCs are required for BDNF-induced OEC migration. GLIA 2016;64:2154-2165.

Olfactory-ensheathing cell transplantation for peripheral nerve repair: update on recent developments

A number of important advances have been made using transplantation of olfactory-ensheathing cells (OECs) to provide therapeutic effects with regard to peripheral nerve repair. In vivo studies have focused on transplanting OECs to stimulate axonal regeneration and sprouting, increase remyelination, confer neuroprotection, enhance neovascularization and replace lost cells. OECs support axonal regeneration and remyelination with appropriate formation of axonal nodes of Ranvier with improvement of nerve conduction velocity. Current work using gene profiling and proteomics is identifying potential therapeutic differences between OECs harvested from nasal mucosa and the olfactory bulb and genes that OECs express that may be conducive to neural repair. OECs derived from nasal mucosa are of clinical interest since the cells could potentially be harvested from a patient and used for autotransplantation. Various nerve scaffolds and materials have been used for nerve repair and recent studies have examined OECs in combination with various supportive materials, including nanoparticles and scaffolds for peripheral nerve substance defects. This review will discuss the use of OECs in nerve repair and nerve defect injuries with specific emphasis on differences between OECs derived from the olfactory bulb and the olfactory mucosa.

From demyelination to remyelination: the road toward therapies for spinal cord injury

Myelin integrity is crucial for central nervous system (CNS) physiology while its preservation and regeneration after spinal cord injury (SCI) is key to functional restoration. Disturbance of nodal organization acutely after SCI exposes the axon and triggers conduction block in the absence of overt demyelination. Oligodendrocyte (OL) loss and myelin degradation follow as a consequence of secondary damage. Here, we provide an overview of the major biological events and underlying mechanisms leading to OL death and demyelination and discuss strategies to restrain these processes. Another aspect which is critical for SCI repair is the enhancement of endogenously occurring spontaneous remyelination. Recent findings have unveiled the complex roles of innate and adaptive immune responses in remyelination and the immunoregulatory potential of the glial scar. Moreover, the intimate crosstalk between neuronal activity, oligodendrogenesis and myelination emphasizes the contribution of rehabilitation to functional recovery. With a view toward clinical applications, several therapeutic strategies have been devised to target SCI pathology, including genetic manipulation, administration of small therapeutic molecules, immunomodulation, manipulation of the glial scar and cell transplantation. The implementation of new tools such as cellular reprogramming for conversion of one somatic cell type to another or the use of nanotechnology and tissue engineering products provides additional opportunities for SCI repair. Given the complexity of the spinal cord tissue after injury, it is becoming apparent that combinatorial strategies are needed to rescue OLs and myelin at early stages after SCI and support remyelination, paving the way toward clinical translation.

Current concept in neural regeneration research: NSCs isolation, characterization and transplantation in various neurodegenerative diseases and stroke: A review

Since last few years, an impressive amount of data has been generated regarding the basic in vitro and in vivo biology of neural stem cells (NSCs) and there is much far hope for the success in cell replacement therapies for several human neurodegenerative diseases and stroke. The discovery of adult neurogenesis (the endogenous production of new neurons) in the mammalian brain more than 40 years ago has resulted in a wealth of knowledge about stem cells biology in neuroscience research. Various studies have done in search of a suitable source for NSCs which could be used in animal models to understand the basic and transplantation biology before treating to human. The difficulties in isolating pure population of NSCs limit the study of neural stem behavior and factors that regulate them. Several studies on human fetal brain and spinal cord derived NSCs in animal models have shown some interesting results for cell replacement therapies in many neurodegenerative diseases and stroke models. Also the methods and conditions used for in vitro culture of these cells provide an important base for their applicability and specificity in a definite target of the disease. Various important developments and modifications have been made in stem cells research which is needed to be more specified and enrolment in clinical studies using advanced approaches. This review explains about the current perspectives and suitable sources for NSCs isolation, characterization, in vitro proliferation and their use in cell replacement therapies for the treatment of various neurodegenerative diseases and strokes.

OECs transplantation results in neuropathic pain associated with BDNF regulating ERK activity in rats following cord hemisection

Background

The olfactory ensheathing cells (OECs) derived from olfactory bulb (OB) may improve motor function after transplantation in injured spinal cord. However, the effects of OEC transplantation on sensory function have not been reported yet. The purpose of this study is to investigate whether OEC transplantation could affect the sensory function and to analyze the underlying mechanism.

Results

OEC transplantation into the hemisected spinal cords can result in hyperalgesia, indicated by radiant and mechanical stimuli towards the plantar surface in rats. This could be associated with upregulation of Brain Derived Neurotrophic Factor (BDNF), indicated by RT-PCR. Immunofluorecent staining showed that BDNF was mainly located in the neurons of the laminas I and II of the dorsal horn. Moreover, a notable upregulation on the level of p-ERK (phosphorylation of extracellular signal-regulated kinase), the downstream molecule of BDNF, was detected by using Western Blot. These findings indicate that the increased BDNF level associated with the p-ERK was possibly involved in neuropathic pain in hemisected spinal cord subjected to OEC transplantation.

Conclusions

The transplantation of OECs may induce the noticeable pain hypersensitivity in rats after hemisected spinal cord injury, and the possible mechanism may be associated with the phosphorylation of ERK and the activated BDNF overexpression.

Mesenchymal autologous stem cells

The use of cell-based therapies for spinal cord injuries has recently gained prominence as a potential therapy or component of a combination strategy. Experimental and clinical studies have been performed using mesenchymal stem cell therapy to treat spinal cord injuries with encouraging results. However, there have been reports on the adverse effects of these stem cell-based therapies, especially in the context of tumor modulation. This article surveys the literature relevant to the potential of mesenchymal autologous stem cells for spinal cord injuries and their clinical implications.

Stem cell therapy: social recognition recovery in a FASD model

To better understand the cellular pathogenetic mechanisms of fetal alcohol spectrum disorder (FASD) and the therapeutic benefit of stem cell treatment, we exposed pregnant rats to ethanol followed by intravenous administration of neural stem cells (NSCs) complexed with atelocollagen to the new born rats and studied recovery of GABAergic interneuron numbers and synaptic protein density in the anterior cingulate cortex, hippocampus and amygdala. Prenatal ethanol exposure reduced both parvalbumin-positive phenotype of GABAergic interneurons and postsynaptic density protein 95 levels in these areas. Intravenous NSC treatment reversed these reductions. Furthermore, treatment with NSCs reversed impaired memory/cognitive function and social interaction behavior. These experiments underscore an important role for synaptic remodeling and GABAergic interneuron genesis in the pathophysiology and treatment of FASD and highlight the therapeutic potential for intravenous NSC administration in FASD utilizing atelocollagen.

Neuroprotective effects of N-acetyl-cysteine and acetyl-L-carnitine after spinal cord injury in adult rats

Following the initial acute stage of spinal cord injury, a cascade of cellular and inflammatory responses will lead to progressive secondary damage of the nerve tissue surrounding the primary injury site. The degeneration is manifested by loss of neurons and glial cells, demyelination and cyst formation. Injury to the mammalian spinal cord results in nearly complete failure of the severed axons to regenerate. We have previously demonstrated that the antioxidants N-acetyl-cysteine (NAC) and acetyl-L-carnitine (ALC) can attenuate retrograde neuronal degeneration after peripheral nerve and ventral root injury. The present study evaluates the effects of NAC and ALC on neuronal survival, axonal sprouting and glial cell reactions after spinal cord injury in adult rats. Tibial motoneurons in the spinal cord were pre-labeled with fluorescent tracer Fast Blue one week before lumbar L5 hemisection. Continuous intrathecal infusion of NAC (2.4 mg/day) or ALC (0.9 mg/day) was initiated immediately after spinal injury using Alzet 2002 osmotic minipumps. Neuroprotective effects of treatment were assessed by counting surviving motoneurons and by using quantitative immunohistochemistry and Western blotting for neuronal and glial cell markers 4 weeks after hemisection. Spinal cord injury induced significant loss of tibial motoneurons in L4–L6 segments. Neuronal degeneration was associated with decreased immunostaining for microtubular-associated protein-2 (MAP2) in dendritic branches, synaptophysin in presynaptic boutons and neurofilaments in nerve fibers. Immunostaining for the astroglial marker GFAP and microglial marker OX42 was increased. Treatment with NAC and ALC rescued approximately half of the motoneurons destined to die. In addition, antioxidants restored MAP2 and synaptophysin immunoreactivity. However, the perineuronal synaptophysin labeling was not recovered. Although both treatments promoted axonal sprouting, there was no effect on reactive astrocytes. In contrast, the microglial reaction was significantly attenuated. The results indicate a therapeutic potential for NAC and ALC in the early treatment of traumatic spinal cord injury.

Transplanted olfactory ensheathing cells reduce retinal degeneration in Royal College of Surgeons rats

PURPOSE OF THE STUDY

Retinitis pigmentosa (RP) is a group of genetic disorders and a slow loss of vision that is caused by a cascade of retinal degenerative events. We examined whether these retinal degenerative events were reduced after cultured mixtures of adult olfactory ensheathing cells (OECs) and olfactory nerve fibroblasts (ONFs) were transplanted into the subretinal space of 1-month-old RCS rat, a classic model of RP.

MATERIALS AND METHODS

The changes in retinal photoreceptors and Müller cells of RCS rats after cell transplantation were observed by the expression of recoverin and glial fibrillary acidic protein (GFAP), counting peanut agglutinin (PNA)-positive cone outer segments and calculating the relative apoptotic area. The retinal function was also evaluated by Flash electroretinography (ERG). To further investigate the mechanisms, by which OECs/ONFs play important roles in the transplanted retinas, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and basic fibroblast growth factor (bFGF) secretion of the cultured cells were analyzed by ELISA. The ability of OECs/ONFs to ingest porcine retinal outer segments and the amount of phagocytosis were compared with retinal pigment epithelium (RPE) cells.

RESULTS

Our research showed that the transplantation of OECs/ONFs mixtures restored recoverin expression, protected retinal outer segments, increased PNA-positive cone outer segments, reduced caspase-positive apoptotic figures, downregulated GFAP, and maintained the b-wave of the ERG. Cultured OECs/ONFs expressed and secreted NGF, BDNF, and bFGF which made contributions to assist survival of the photoreceptors. An in vitro phagocytosis assay showed that OECs, but not ONFs, phagocytosed porcine retinal outer segments, and the phagocytic ability of OECs was even superior to that of RPE cells.

CONCLUSIONS

These findings demonstrate that transplantation of OECs/ONFs cleaned up the accumulated debris in subretinal space, and provided an intrinsic continuous supply of neurotrophic factors. It suggested that transplantation of OECs/ONFs might be a possible future route for protection of the retina and reducing retinal degeneration in RP.

Corticospinal reorganization after spinal cord injury

The corticospinal tract (CST) is a major descending pathway contributing to the control of voluntary movement in mammals. During the last decades anatomical and electrophysiological studies have demonstrated significant reorganization in the CST after spinal cord injury (SCI) in animals and humans. In animal models of SCI, anatomical evidence showed corticospinal sprouts rostral and caudal to the lesion and their integration into intraspinal axonal circuits. Electrophysiological data suggested that indirect connections from the primary motor cortex to forelimb motoneurons, via brainstem nuclei and spinal cord interneurons, or direct connections from slow uninjured corticospinal axons, might contribute to the control of movement after a CST injury. In humans with SCI, post mortem spinal cord tissue revealed anatomical changes in the CST some of which were similar but others markedly different from those found in animal models of SCI. Human electrophysiological studies have provided ample evidence for corticospinal reorganization after SCI that may contribute to functional recovery. Together these studies have revealed a large plastic capacity of the CST after SCI. There is also a limited understanding of the relationship between anatomical and electrophysiological changes in the CST and control of movement after SCI. Increasing our knowledge of the role of CST plasticity in functional restoration after SCI may support the development of more effective repair strategies.

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.

CNPase expression in olfactory ensheathing cells

A large body of work supports the proposal that transplantation of olfactory ensheathing cells (OECs) into nerve or spinal cord injuries can promote axonal regeneration and remyelination. Yet, some investigators have questioned whether the transplanted OECs associate with axons and form peripheral myelin, or if they recruit endogenous Schwann cells that form myelin. Olfactory bulbs from transgenic mice expressing the enhanced green fluorescent protein (eGFP) under the control of the 2-3-cyclic nucleotide 3-phosphodiesterase (CNPase) promoter were studied. CNPase is expressed in myelin-forming cells throughout their lineage. We examined CNPase expression in both in situ in the olfactory bulb and in vitro to determine if OECs express CNPase commensurate with their myelination potential. eGFP was observed in the outer nerve layer of the olfactory bulb. Dissociated OECs maintained in culture had both intense eGFP expression and CNPase immunostaining. Transplantation of OECs into transected peripheral nerve longitudinally associated with the regenerated axons. These data indicate that OECs in the outer nerve layer of the olfactory bulb of CNPase transgenic mice express CNPase. Thus, while OECs do not normally form myelin on olfactory nerve axons, their expression of CNPase is commensurate with their potential to form myelin when transplanted into injured peripheral nerve.

A reassessment of whether cortical motor neurons die following spinal cord injury

Over the past century, the question of whether the cells of origin of the corticospinal tract (CST) die following spinal cord injury (SCI) has been debated. A recent study reported an approximately 20% loss of retrogradely labeled cortical motoneurons following damage to their axons resulting from SCI at T9 (Hains et al. [2003] J. Comp. Neurol. 462:328-341). In follow-up studies, however, we failed to find any evidence of loss of CST axons in the medullary pyramid, which must occur if CST neurons die. Here, we seek to resolve the discrepancy by re-evaluating possible loss of CST neurons using the same techniques as Hains et al. (quantitative analysis of retrograde labeling and staining for cell death markers including TUNEL and Hoechst labeling of the nuclei). Following either dorsal funiculus lesions at thoracic level 9 (T9) or lateral hemisection at cervical level 5 (C5), our results reveal no evidence for a loss of retrogradely labeled neurons and no evidence for TUNEL staining of axotomized cortical motoneurons. These results indicate that CST cell bodies do not undergo retrograde cell death following SCI, and therefore targeting such cell death is not a valid therapeutic target.

Expression of plasminogen activator inhibitor-1 by olfactory ensheathing glia promotes axonal regeneration

Olfactory ensheathing glia (OEG) cells are known to facilitate repair following axotomy of adult neurons, although the molecular mechanisms involved are not fully understood. We previously identified plasminogen activator inhibitor-1 (PAI-1), proteinase-activated receptor-1 (PAR-1), and thrombomodulin (TM) as candidates to regulate rat OEG-dependent axonal regeneration. In this study, we have validated the involvement of these proteins in promoting axonal regeneration by immortalized human OEGs. We studied the effect of silencing these proteins in OEGs on their capacity to promote the regeneration of severed adult retinal ganglion cells (RGCs) axons. Our results support the role of glial PAI-1 as a downstream effector of PAR-1 in promoting axon regeneration. In contrast, we found that TM inhibits OEG induced-axonal regeneration. We also assessed the signaling pathways downstream of PAR-1 that might modulate PAI-1 expression, observing that specifically inhibiting Gα(i), Rho kinase, or PLC and PKC downregulated the expression of PAI-1 in OEGs, with a concomitant reduction in OEG-dependent axon regeneration in adult RGCs. Our findings support an important role for the thrombin system in regulating adult axonal regeneration by OEGs.

Transplanted olfactory ensheathing cells reduce the gliotic injury response of Müller cells in a rat model of retinitis pigmentosa

Retinitis pigmentosa leads to progressive visual loss and blindness. Until now there has been no effective therapy. Experimental studies have shown that transplantation of olfactory ensheathing cells into CNS lesions reorganizes the glial scar and stimulates axon regeneration. We now report that cultured syngeneic adult rat olfactory ensheathing cells transplanted into the subretinal space of pigmented Royal College of Surgeon rats survived for a minimum of 8weeks, migrated into surrounding space, and suppressed the gliotic injury response of the Müller cells. Further investigation of intraretinal transplantation of olfactory ensheathing cells may suggest a possible future route for protection of the retina in retinitis pigmentosa.

Combination of olfactory ensheathing cells with local versus systemic cAMP treatment after a cervical rubrospinal tract injury

The failure of CNS axons to regenerate following traumatic injury is due in part to a growth-inhibitory environment in CNS as well as a weak intrinsic neuronal growth response. Olfactory ensheathing cell (OECs) transplants have been reported to create a favorable environment promoting axonal regeneration, remyelination, and functional recovery after spinal cord injury. However, in our previous experiments, OEC transplants failed to promote regeneration of rubrospinal axons through and beyond the site of a dorsolateral funiculus crush in rats. Rubrospinal neurons undergo massive cell atrophy and limited expression of regeneration-associated genes after axotomy. Using the same injury model, we tested the hypothesis that treatment of the red nucleus with cAMP, known to stimulate the intrinsic growth response in other neurons, will promote rubrospinal regeneration in combination with OEC transplants. In addition, we assessed a systemic increase of cAMP using the phosphodiesterase inhibitor rolipram. OECs prevented cavity formation, attenuated astrocytic hypertrophy and the retraction of the axotomized rubrospinal axons, and tended to reduce the overall lesion size. OEC transplantation lowered the thresholds for thermal sensitivity of both forepaws. None of our treatments, alone or in combination, promoted rubrospinal regeneration through the lesion site. However, the systemic elevation of cAMP with rolipram resulted in greater numbers of OECs and axonal density within the graft and improved motor performance in a cylinder test in conjunction with enhanced rubrospinal branching and attenuated astrocytic hypertrophy.

Olfactory ensheathing cells promote neurite outgrowth from co-cultured brain stem slice

Cell therapy aiming at the replacement of degenerated neurons is a very attractive approach. By using an established in vitro organotypic brain stem (BS) slice culture we screen for candidate donor cells, some of them being further functionally assessed in in vivo models of sensorineural hearing loss. Both in vitro and in vivo systems show that implanted cells face challenges of survival, targeted migration, differentiation and functional integration with the host tissue. Low success rates are possibly due to the lack of necessary neurotrophic factors, adhesion molecules and guiding cues. Olfactory ensheathing cells (OECs) have been shown to express a number of neurotrophic factors and to promote axonal growth through cell to cell interactions. In the present study we co-cultured OECs with organotypic BS slice in order to see if OECs can serve as a facilitator when screening candidate donor cells in an organotypic culture setup. Here we show that OECs when co-cultured with the auditory BS slice not only promote neurite outgrowth from the cochlear nucleus (CN) region of the BS slice but also support cells by having BS slice axons growing along their processes. These findings further suggest that OECs may enhance survival and targeted migration of candidate donor cells suitable for cell therapy in vitro and in vivo. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.

Efficacy of olfactory ensheathing cells to support regeneration after spinal cord injury is influenced by method of culture preparation

Olfactory ensheathing cells (OEC) have been shown to stimulate regeneration, myelination and functional recovery in different spinal cord injury models. However, recent reports from several laboratories have challenged this treatment strategy. The discrepancy in results could be attributed to many factors including variations in culture protocols. The present study investigates whether the differences in culture preparation could influence neuroprotective and growth-promoting effects of OEC after transplantation into the injured spinal cord. Primary OEC cultures were purified using method of differential cell adhesion (a-OEC) or separated with immunomagnetic beads (b-OEC). After cervical C4 hemisection in adult rats, short-term (3 weeks) or long-term (7 weeks) cultured OEC were transplanted into the lateral funiculus at 1mm rostral and caudal to the transection site. At 3-8 weeks after transplantation, labeled OEC were mainly found in the injection sites and in the trauma zone. Short-term cultured a-OEC supported regrowth of rubrospinal, raphaespinal and CGRP-positive fibers, and attenuated retrograde degeneration in the red nucleus. Short-term cultured b-OEC failed to promote axonal regrowth but increased the density of rubrospinal axons within the dorsolateral funiculus and provided significant neuroprotection for axotomized rubrospinal neurons. In addition, short-term cultured OEC attenuated sprouting of rubrospinal terminals. In contrast, long-term cultured OEC neither enhanced axonal growth nor prevented retrograde cell death. The results suggest that the age of OEC in culture and the method of cell purification could affect the efficacy of OEC to support neuronal survival and regeneration after spinal cord injury. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.

Manipulating the glial scar: chondroitinase ABC as a therapy for spinal cord injury

Chondroitin sulphate proteoglycans (CSPGs) are potent inhibitors of growth in the adult CNS. Use of the enzyme chondroitinase ABC (ChABC) as a strategy to reduce CSPG inhibition in experimental models of spinal cord injury has led to observations of a remarkable capacity for repair. Here we review the evidence that treatment with ChABC, either as an individual therapy or in combination with other strategies, can have multiple beneficial effects on promoting repair following spinal cord injury. These include promoting regeneration of injured axons, plasticity of uninjured pathways and neuroprotection of injured projection neurons. More importantly, ChABC therapy has been demonstrated to promote significant recovery of function to spinal injured animals. Thus, there is robust pre-clinical evidence demonstrating beneficial effects of ChABC treatment following spinal cord injury. Furthermore, these effects have been replicated in a number of different injury models, with independent confirmation by different laboratories, providing an important validation of ChABC as a promising therapeutic strategy. We discuss putative mechanisms underlying ChABC-mediated repair as well as potential issues and considerations in translating ChABC treatment into a clinical therapy for spinal cord injury.

Intravenous administration of mesenchymal stem cells derived from bone marrow after contusive spinal cord injury improves functional outcome

Transplantation of mesenchymal stem cells (MSCs) derived from bone marrow has been shown to improve functional outcome in spinal cord injury (SCI). Systemic delivery of MSCs results in therapeutic benefits in a number of experimental central nervous system disorders. In the present study we intravenously administered rat MSCs derived from bone marrow at various time points after induction of a severe contusive SCI in rat to study their therapeutic effects. MSCs were systemically delivered at varied time points (6h to 28 days after SCI). The spinal cords were examined histologically 6 weeks after SCI. Stereological quantification was performed on the spinal cords to determine donor cell (MSCs transduced with the LacZ gene) density in the lesions. Light microscopic examination revealed that cavitation in the contused spinal cords was less in the MSC-treated rats. A limited number of cells derived from MSCs (LacZ(+)) in the injury site expressed neural or glial markers. Functional outcome measurements using the Basso-Beattie-Bresnehan (BBB) score were performed periodically up to 6 weeks post-SCI. Locomotor recovery improvement was greater in the MSC-treated groups than in sham controls with greatest improvement in the earlier post-contusion infusion times. The availability of autologous MSCs in large number and the potential for systemically delivering cells to target lesion areas without neurosurgical intervention suggests the potential utility of intravenous cell delivery as a prospective therapeutic approach in acute and subacute SCI.

Intracranial transplant of olfactory ensheathing cells in children and adolescents with cerebral palsy: a randomized controlled clinical trial

Successful repair of damage in cerebral palsy (CP) needs effective clinical interventions other than simply symptomatic treatments. To elucidate the feasibility of using olfactory ensheathing cells (OECs) to treat CP in children and adolescents, we conducted a randomized controlled clinical trial (RCT) on 33 patients. The patients were randomly assigned into two groups (treatment group, n = 18; control group, n = 15), and OECs derived from aborted fetal tissue were injected into the bilateral corona radiata in the frontal lobes (a key point for neural network restoration, KPNNR). The Gross Motor Function Measure (GMFM-66) and the Caregiver Questionnaire Scale were used to evaluate the patients' neurological function and overall health status. Among the 14 patients who completed the 6-month study, six received the cell transplantation and the other eight served as controls. In OEC treatment group, GMFM-66 scores were 26.67 +/- 25.33 compared with 19.00 +/- 20.00 for the control group. Concurrently, the Caregiver Questionnaire Scale score decreased to 77.83 +/- 15.99 in the treatment group in comparison to 138.66 +/- 64.06 of the control group. This trial, albeit small in sample size, indicates OEC KPNNR transplantation is effective for functional improvement in children and adolescents with CP, yet without obvious side effects. This small-scale study suggests that the procedure may be a plausible alternative method to treat this not yet curable disorder, and we urge further evaluation with a large-scale RCT.

Cell Therapy From Bench to Bedside Translation in CNS Neurorestoratology Era

Recent advances in cell biology, neural injury and repair, and the progress towards development of neurorestorative interventions are the basis for increased optimism. Based on the complexity of the processes of demyelination and remyelination, degeneration and regeneration, damage and repair, functional loss and recovery, it would be expected that effective therapeutic approaches will require a combination of strategies encompassing neuroplasticity, immunomodulation, neuroprotection, neurorepair, neuroreplacement, and neuromodulation. Cell-based restorative treatment has become a new trend, and increasing data worldwide have strongly proven that it has a pivotal therapeutic value in CNS disease. Moreover, functional neurorestoration has been achieved to a certain extent in the CNS clinically. Up to now, the cells successfully used in preclinical experiments and/or clinical trial/treatment include fetal/embryonic brain and spinal cord tissue, stem cells (embryonic stem cells, neural stem/progenitor cells, hematopoietic stem cells, adipose-derived adult stem/precursor cells, skin-derived precursor, induced pluripotent stem cells), glial cells (Schwann cells, oligodendrocyte, olfactory ensheathing cells, astrocytes, microglia, tanycytes), neuronal cells (various phenotypic neurons and Purkinje cells), mesenchymal stromal cells originating from bone marrow, umbilical cord, and umbilical cord blood, epithelial cells derived from the layer of retina and amnion, menstrual blood-derived stem cells, Sertoli cells, and active macrophages, etc. Proof-of-concept indicates that we have now entered a new era in neurorestoratology.

Death of Axotomized Retinal Ganglion Cells Delayed after Intraoptic Nerve Transplantation of Olfactory Ensheathing Cells in Adult Rats

Intraorbital transection of the optic nerve (ON) always induces ultimate apoptosis of retinal ganglion cells (RGCs) and consequently irreversible defects of vision function. It was demonstrated that transplanted olfactory ensheathing cells (OECs) in partially injured spinal cord have a distant in vivo neuroprotective effect on descending cortical and brain stem neurons. However, this study gave no answers to the question whether OECs can protect the central sensitive neurons with a closer axonal injury because different neurons respond variously to similar axonal injury and the distance between the neuronal soma and axonal injury site has a definite effect on the severity of neuronal response and apoptosis. In the present study, we investigated the effect of transplanted OECs on RGCs after intraorbital ON transection in adult rats. Green fluorescent protein (GFP)-OECs were injected into the ocular stumps of transected ON and a significantly higher number of surviving RGCs was found together with a consistent marked increase in the mRNA and protein levels of BDNF in the ON stump and retina in the OEC-treated group at 7 days, but not 2 and 14 days, time point when compared to the control group. Our findings suggest that OEC transplantation induces the expression of BDNF in the ocular ON stump and retina and delays the death of axotomized RGCs at a certain survival period.

BDNF-hypersecreting human mesenchymal stem cells promote functional recovery, axonal sprouting, and protection of corticospinal neurons after spinal cord injury

Transplantation of mesenchymal stem cells (MSCs) derived from bone marrow has been shown to improve functional outcome in spinal cord injury (SCI). We transplanted MSCs derived from human bone marrow (hMSCs) to study their potential therapeutic effect in SCI in the rat. In addition to hMSCs, we used gene-modified hMSCs to secrete brain-derived neurotrophic factor (BDNF-hMSCs). After a dorsal transection lesion was induced at T9, cells were microinjected on each side of the transection site. Fluorogold (FG) was injected into the epicenter of the lesion cavity to identify transected corticospinal tract (CST) neurons. At 5 weeks after transplantation, the animals were perfused. Locomotor recovery improvement was observed for the BDNF-hMSC group, but not in the hMSC group. Structurally there was increased sprouting of injured corticospinal tract and serotonergic projections after hMSC and BDNF-hMSC transplantation. Moreover, an increased number of serotonergic fibers was observed in spinal gray matter including the ventral horn at and below the level of the lesion, indicating increased innervation in the terminal regions of a descending projection important for locomotion. Stereological quantification was performed on the brains to determine neuronal density in primary motor (M1) cortex. The number of FG backfilled cells demonstrated an increased cell survival of CST neurons in M1 cortex in both the hMSC and BDNF-hMSC groups at 5 weeks, but the increase for the BDNF-hMSC group was greater. These results indicate that transplantation of hMSCs hypersecreting BDNF results in structural changes in brain and spinal cord, which are associated with improved functional outcome in acute SCI.