Chondroitinase ABC combined with neural stem/progenitor cell transplantation enhances graft cell migration and outgrowth of growth-associated protein-43-positive fibers after rat spinal cord injury

We previously reported that the transplantation of neural stem/progenitor cells (NSPCs) can contribute to the repair of injured spinal cord in adult rats and monkeys. In some cases, however, most of the transplanted cells adhered to the cavity wall and failed to migrate and integrate into the host spinal cord. In this study we focused on chondroitin sulfate proteoglycan (CSPG), a known constituent of glial scars that is strongly expressed after spinal cord injury (SCI), as a putative inhibitor of NSPC migration in vivo. We hypothesized that the digestion of CSPG by chondroitinase ABC (C-ABC) might promote the migration of transplanted cells and neurite outgrowth after SCI. An in vitro study revealed that the migration of NSPC-derived cells was inhibited by CSPG and that this inhibitory effect was attenuated by C-ABC pre-treatment. Consistently, an in vivo study of C-ABC treatment combined with NSPC transplantation into injured spinal cord revealed that C-ABC pre-treatment promoted the migration of the transplanted cells, whereas CSPG-immunopositive scar tissue around the lesion cavity prevented their migration into the host spinal cord in the absence of C-ABC pre-treatment. Furthermore, this combined treatment significantly induced the outgrowth of a greater number of growth-associated protein-43-positive fibers at the lesion epicentre, compared with NSPC transplantation alone. These findings suggested that the application of C-ABC enhanced the benefits of NSPC transplantation for SCI by reducing the inhibitory effects of the glial scar, indicating that this combined treatment may be a promising strategy for the regeneration of injured spinal cord.     

Transplantation of human neural stem cells for spinal cord injury in primates

Recent studies have shown that delayed transplantation of neural stem/progenitor cells (NSPCs) into the injured spinal cord can promote functional recovery in adult rats. Preclinical studies using nonhuman primates, however, are necessary before NSPCs can be used in clinical trials to treat human patients with spinal cord injury (SCI). Cervical contusion SCIs were induced in 10 adult common marmosets using a stereotaxic device. Nine days after injury, in vitro-expanded human NSPCs were transplanted into the spinal cord of five randomly selected animals, and the other sham-operated control animals received culture medium alone. Motor functions were evaluated through measurements of bar grip power and spontaneous motor activity, and temporal changes in the intramedullary signals were monitored by magnetic resonance imaging. Eight weeks after transplantation, all animals were sacrificed. Histologic analysis revealed that the grafted human NSPCs survived and differentiated into neurons, astrocytes, and oligodendrocytes, and that the cavities were smaller than those in sham-operated control animals. The bar grip power and the spontaneous motor activity of the transplanted animals were significantly higher than those of sham-operated control animals. These findings show that NSPC transplantation was effective for SCI in primates and suggest that human NSPC transplantation could be a feasible treatment for human SCI.     

Embryonic and adult stem cells promote raphespinal axon outgrowth and improve functional outcome following spinal hemisection in mice

Spinal cord injury (SCI) often results in permanent neurological deficits below the injury site. Serotonergic raphespinal projections promote functional recovery after SCI, but spontaneous regeneration of most severed axons is limited by the glial cyst and scar that form at the lesion site. Stem cell (SC) transplantation offers a promising approach for inducing regeneration through the damaged area. Here we compare the effects of transplantation of embryonic neural precursors (NPs) or adult mesenchymal SCs, both of which are potential candidates for SC therapy. The spinal cord was hemisected at the L2 neuromer in adult mice. Two weeks post-injury, we transplanted neural precursors or mesenchymal SCs into the cord, caudal to the hemisection. Injured mice without a graft served as controls. Mice were tested for functional recovery on a battery of motor tasks, then killed and analysed for survival of grafted cells, for effects of engraftment on the local cellular environment and for the sprouting of serotonergic axons. Both types of SCs survived and were integrated into the host tissue, but only the NPs expressed neuronal markers. All transplanted animals displayed an increased number of serotonin-positive fibres caudal to the hemisection, compared with untreated mice. And both cell types led to improved motor performance. These results point to a therapeutic potential for such cell grafting.     

Transplanted neural stem/progenitor cells generate myelinating oligodendrocytes and Schwann cells in spinal cord demyelination and dysmyelination

Stem cell therapy is a promising approach for remyelination strategies in demyelinating and traumatic disorders of the spinal cord. Self-renewing neural stem/progenitor cells (NSPCs) reside in the adult mammalian brain and spinal cord. We transplanted NSPCs derived from the adult spinal cord of transgenic rats into two models of focal demyelination and congenital dysmyelination. Focal demyelination was induced by X-irradiation and ethidium bromide injection (X-EB); and dysmyelination was in adult shiverer mutant mice, which lack compact CNS myelin. We examined the differentiation potential and myelinogenic capacity of NSPCs transplanted into the spinal cord. In X-EB lesions, the transplanted cells primarily differentiated along an oligodendrocyte lineage but only some of the oligodendrocytic progeny remyelinated host axons. In this glial-free lesion, NSPCs also differentiated into cells with Schwann-like features based on ultrastructure, expression of Schwann cell markers, and generation of peripheral myelin. In contrast, after transplantation into the spinal cord of adult shiverer mice, the majority of the NSPCs expressed an oligodendrocytic phenotype which myelinated the dysmyelinated CNS axons forming compact myelin, and none had Schwann cell-like features. This is the first study to examine the differentiation and myelinogenic capacity of adult spinal cord stem/progenitors in focal demyelination and dysmyelination of the adult rodent spinal cord. Our findings demonstrate that these NSPCs have the inherent plasticity to differentiate into oligodendrocytes or Schwann-like cells depending on the host environment, and that both cell types are capable of myelinating axons in the demyelinated and dysmyelinated adult spinal cord.     

Comparison between fetal spinal-cord- and forebrain-derived neural stem/progenitor cells as a source of transplantation for spinal cord injury

Recently, we have shown that the transplantation of spinal-cord-derived neural stem/progenitor cells (NSPCs) can contribute to the repair of injured spinal cords in adult rats, which may correspond to a behavioral recovery. To apply these results to clinical practice, a system for supplying human NSPCs on a large scale must be established. However, human spinal-cord-derived NSPCs are known to have a low proliferation rate, compared with forebrain-derived NSPCs. This low proliferative potency limits the feasibility of large-scale spinal cord-derived NSPC use. Thus, forebrain-derived NSPCs should be examined as an alternative to spinal-cord-derived NSPCs for the treatment of spinal cord injuries. In this study, we compared spinal-cord- and forebrain-derived NSPCs transplanted into injured spinal cords with respect to their fates in vivo as well as the animals' functional recovery. Both spinal-cord- and forebrain-derived NSPCs promoted functional recovery in rats with spinal cord injuries. While both spinal-cord- and forebrain-derived NSPCs survived, migrated and differentiated into neurons, astrocytes and oligodendrocytes in response to the microenvironment within the injured spinal cord after transplantation, forebrain-derived NSPCs differentiated into more neurons and fewer oligodendrocytes, compared to spinal-cord-derived NSPCs. Neurons that had differentiated from the transplanted forebrain-derived NSPCs were shown to be positive for neurotransmitters like GABA, glutamate and glycine, although authentic glycinergic neurons are not normally present within the forebrain. Thus, at least a subpopulation of the transplanted forebrain-derived NSPCs differentiated into spinal-cord-type neurons. In conclusion, forebrain-derived NSPCs could be used as an alternative to spinal-cord-derived NSPCs as a potential therapeutic agent for spinal cord injuries.     

Blockade of interleukin-6 receptor suppresses reactive astrogliosis and ameliorates functional recovery in experimental spinal cord injury

Endogenous neural stem/progenitor cells (NSPCs) have recently been shown to differentiate exclusively into astrocytes, the cells that are involved in glial scar formation after spinal cord injury (SCI). The microenvironment of the spinal cord, especially the inflammatory cytokines that dramatically increase in the acute phase at the injury site, is considered to be an important cause of inhibitory mechanism of neuronal differentiation following SCI. Interleukin-6 (IL-6), which has been demonstrated to induce NSPCs to undergo astrocytic differentiation selectively through the JAK/STAT pathway in vitro, has also been demonstrated to play a critical role as a proinflammatory cytokine and to be associated with secondary tissue damage in SCI. In this study, we assessed the efficacy of rat anti-mouse IL-6 receptor monoclonal antibody (MR16-1) in the treatment of acute SCI in mice. Immediately after contusive SCI with a modified NYU impactor, mice were intraperitoneally injected with a single dose of MR16-1 (100 microg/g body weight), the lesions were assessed histologically, and the functional recovery was evaluated. MR16-1 not only suppressed the astrocytic diffentiation-promoting effect of IL-6 signaling in vitro but inhibited the development of astrogliosis after SCI in vivo. MR16-1 also decreased the number of invading inflammatory cells and the severity of connective tissue scar formation. In addition, we observed significant functional recovery in the mice treated with MR16-1 compared with control mice. These findings suggest that neutralization of IL-6 signaling in the acute phase of SCI represents an attractive option for the treatment of SCI.     

脑脊液内细胞移植治疗脊髓损伤

经脑脊液进行细胞移植治疗脊髓损伤具有较大的临床应用前景.有关研究显示,经脑脊液进行的细胞移植方法安全、方便,对病人的损伤小,适用于治疗中枢神经系统多发疾病.但是经脑脊液移植的细胞能否促进中枢神经系统轴突再生和脊髓神经功能修复仍存在争议,其作用机制、移植时间以及移植细胞种类方面还需要进一步研究.本文对经脑脊液细胞移植方法用于治疗脊髓损伤进行综述,探讨此方法对脊髓损伤后中枢神经系统内轴突再生及功能修复的促进作用.     

BDNF-GFP转染神经干细胞修复大鼠脊髓损伤：发挥干细胞与神经因子的双重效应？

摘要 背景：神经干细胞移植入大鼠脊髓损伤模型可以促进功能恢复,基因治疗已被广泛用于治疗脊髓损伤。 目的：确定BDNF-GFP转染后神经干细胞移植对大鼠脊髓损伤的修复效果。 设计,时间和背景：本实验是在中国医科大学基础医学院发育生物学实验室与2009年5月至2010年1月完成。 材料：10只新生Wistar大鼠和88只2-3个月大,雌雄不限的Wistar大鼠。 方法：以携带BDNF-GFP基因的腺病毒转染神经干细胞。88只Wistar大鼠中假手术组8只, 80只大鼠制成T9左侧横断模型,并随机分成四组：BDNF和GFP修饰的神经干细胞移植组,GFP修饰的神经干细胞移植组;单纯神经干细胞移植组和模型组。在各神经干细胞移植组,脊髓损伤后向横断处显微注射等体积细胞,模型组在相同的部位注射等体积的PBS。 主要观察指标： BBB评分检测脊髓损伤模型运动功能恢复情况;制备脊髓损伤模型2周后取材,免疫组化评估BDNF-GFP转染的神经干细胞移植后的细胞学特点;制备脊髓损伤模型2、4、6、8周Real-time PCR检测脊髓横断处BDNF表达情况。 结果： BDNF-GFP转染后神经干细胞在脊髓半切模型中存活并表达BDNF和GFP,移植该细胞后的大鼠体内高表达具有生物活性的BDNF,且脊髓损伤动物运动功能较对照组明显恢复。 结论：移植BDNF-GFP转染后神经干细胞可能是一种修复脊髓损伤的有效的方法。 关键词：神经干细胞,脑源性神经营养因子;绿色荧光蛋白;脊髓损伤;移植。     

Cell-based transplantation strategies to promote plasticity following spinal cord injury

Cell transplantation therapy holds potential for repair and functional plasticity following spinal cord injury (SCI). Stem and progenitor cells are capable of modifying the lesion environment, providing structural support and myelination and increasing neurotrophic factors for neuroprotection and endogenous activation. Through these effects, transplanted cells induce plasticity in the injured spinal cord by promoting axonal elongation and collateral sprouting, remyelination, synapse formation and reduced retrograde axonal degeneration. In light of these beneficial effects, cell transplantation could be combined with other treatment modalities, such as rehabilitation and immune modulation, to provide a synergistic functional benefit. This review will delineate 1) stem/progenitor cell types proposed for cell transplantation in SCI, 2) in vitro evidence of cell-induced mechanisms of plasticity, 3) promotion of functional recovery in animal models of SCI, 4) successful combinatorial strategies using cell transplantation. Current treatment modalities for SCI provide modest efficacy, especially in chronic stages of SCI. Hence, combinatorial stem cell transplantation strategies which could potentially directly address tissue sparing and neuroplasticity in chronic SCI show promise. Rigorous evaluation of combinatorial approaches using stem cell transplantation with appropriate preclinical animal models of SCI is needed to advance therapeutic strategies to the point where clinical trials are appropriate. Given the high patient demand for and clinical trial precedent of cell transplantation therapy, combination stem cell therapies have the promise to provide improved quality of life for individuals, with corresponding socioeconomic benefit.     

Cell transplantation for the treatment of spinal cord injury–bone marrow stromal cells and choroid plexus epithelial cells

Transplantation of bone marrow stromal cells(BMSCs) enhanced the outgrowth of regenerating axons and promoted locomotor improvements of rats with spinal cord injury(SCI).BMSCs did not survive long-term,disappearing from the spinal cord within 2–3 weeks after transplantation.Astrocyte-devoid areas,in which no astrocytes or oligodendrocytes were found,formed at the epicenter of the lesion.It was remarkable that numerous regenerating axons extended through such astrocyte-devoid areas.Regenerating axons were associated with Schwann cells embedded in extracellular matrices.Transplantation of choroid plexus epithelial cells(CPECs) also enhanced axonal regeneration and locomotor improvements in rats with SCI.Although CPECs disappeared from the spinal cord shortly after transplantation,an extensive outgrowth of regenerating axons occurred through astrocyte-devoid areas,as in the case of BMSC transplantation.These findings suggest that BMSCs and CPECs secret neurotrophic factors that promote tissue repair of the spinal cord,including axonal regeneration and reduced cavity formation.This means that transplantation of BMSCs and CPECs promotes "intrinsic" ability of the spinal cord to regenerate.The treatment to stimulate the intrinsic regeneration ability of the spinal cord is the safest method of clinical application for SCI.It should be emphasized that the generally anticipated long-term survival,proliferation and differentiation of transplanted cells are not necessarily desirable from the clinical point of view of safety.     

Combined transplantation of bone marrow mesenchymal stem cells and pedicled greater omentum promotes locomotor function and regeneration of axons after spinal cord injury in rats*★

BACKGROUND： According to previous studies, the neuroprotective effect of the pedicled greater omentum may be attributed to the secretion of neurotrophic factors and stimulation of angiogenesis. The neurotrophic factors released from the pedicled greater omentum, such as brain-derived neurotrophic factor and neurotrophin 3/4/5 could exert a neuroprotective effect on the damaged host neural and glial cells, and also could induce the transdifferentiation of transplanted bone marrow mesenchymal stem cells （BMSCs） into neural cells. OBJECTIVE： Based on the functions of the omentum of neuro-protection and vascularization, we hypothesize that the transplantation of BMSCs and pedicled greater omentum into injured rat spinal cord might improve the survival rate and neural differentiation of transplanted BMSCs and consequently gain a better functional outcome. DESIGN, TIME AND SETFING： A randomized, controlled animal experiment. The experiments were carried out at the Department of Anatomy, the Secondary Military Medical University of Chinese PLA between June 2005 and June 2007. MATERIALS： Fifteen male inbred Wistar rats, weighing （200±20） g, provided by the Experimental Animal Center of the Secondary Military Medical University of Chinese PLA were used and met the animal ethical standards. Mouse anti-BrdU and mouse anti-NF200 monoclonal antibody were purchased from Boster, China. METHODS： Cell culture： We used inbred Sprague-Dawley rats to harvest bone marrow for culture of BMSCs and transplantation to avoid possible immune rejection. BMSCs were cultured via total bone marrow adherence. Experimental grouping and intervention： The rats were randomly divided into a control group, cell group and combined group, five rats per group. Rats in the control group underwent spinal cord injury （SCI） only, during which an artery clamp with pressure force of 30 g was employed to compress the spinal cord at the Tl0 level for 30 seconds to produce the SCI model. 5 μ L PBS containing 10^5 BMSCs was injected in     

Valproic Acid Increases Expression of Neuronal Stem/Progenitor Cell in Spinal Cord Injury

Objective

This study investigates the effect of valproic acid (VPA) on expression of neural stem/progenitor cells (NSPCs) in a rat spinal cord injury (SCI) model.

Methods

Adult male rats (n=24) were randomly and blindly allocated into three groups. Laminectomy at T9 was performed in all three groups. In group 1 (sham), only laminectomy was performed. In group 2 (SCI-VPA), the animals received a dose of 200 mg/kg of VPA. In group 3 (SCI-saline), animals received 1.0 mL of the saline vehicle solution. A modified aneurysm clip with a closing force of 30 grams was applied extradurally around the spinal cord at T9, and then rapidly released with cord compression persisting for 2 minutes. The rats were sacrificed and the spinal cord were collected one week after SCI. Immunohistochemistry (IHC) and western blotting sample were obtained from 5 mm rostral region to the lesion and prepared. We analyzed the nestin immunoreactivity from the white matter of ventral cord and the ependyma of central canal. Nestin and SOX2 were used for markers for NSPCs and analyzed by IHC and western blotting, respectively.

Results

Nestin and SOX2 were expressed significantly in the SCI groups but not in the sham group. Comparing SCI groups, nestin and SOX2 expression were much stronger in SCI-VPA group than in SCI-saline group.

Conclusion

Nestin and SOX2 as markers for NSPCs showed increased expression in SCI-VPA group in comparison with SCI-saline group. This result suggests VPA increases expression of spinal NSPCs in SCI.     

Multipotent embryonic spinal cord stem cells expanded by endothelial factors and Shh/RA promote functional recovery after spinal cord injury

Cell transplantation is a promising way to treat spinal cord injury and neurodegenerative disorders. Neural stem cells taken from the embryonic spinal cord are an appealing source of cells for transplantation because these cells are committed to making spinal cord progeny. However these stem cells are rare and require expansion in tissue culture to generate sufficient cells for transplantation. We have developed a novel method for expanding embryonic mouse spinal cord stem cells using a co-culture system with endothelial cells. This method improves neural stem cell survival and preserves their multipotency, including their ability to make motor neurons. Transplantation of endothelial-expanded neural stem cells that were treated with sonic hedgehog(Shh) and retinoic acid (RA) during the expansion phase, into an adult mouse SCI model resulted in significant recovery of sensory and motor function.     

The combination of induced pluripotent stem cells and bioscaffolds holds promise for spinal cord regeneration

Spinal cord injuries(SCIs) are debilitating conditions for which no effective treatment currently exists. The damage of neural tissue causes disruption of neural tracts and neuron loss in the spinal cord. Stem cell replacement offers a solution for SCI treatment by providing a source of therapeutic cells for neural function restoration. Induced pluripotent stem cells(i PSCs) have been investigated as a potential type of stem cell for such therapies. Transplantation of i PSCs has been shown to be effective in restoring function after SCIs in animal models while they circumvent ethical and immunological concerns produced by other stem cell types. Another approach for the treatment of SCI involves the graft of a bioscaffold at the site of injury to create a microenvironment that enhances cellular viability and guides the growing axons. Studies suggest that a combination of these two treatment methods could have a synergistic effect on functional recovery post-neural injury. While much progress has been made, more research is needed before clinical trials are possible. This review highlights recent advancements using i PSCs and bioscaffolds for treatment of SCI.     

Stem cells for spinal cord injuries bearing translational potential

Spinal cord injury(SCI) is a highly debilitating neurological disease, which still lacks effective treatment strategies, causing significant financial burden and distress to the affected families. Nevertheless, nanotechnology and regenerative medicine strategies holding promise for the development of novel therapies that would reach from bench to bedside to serve the SCI patients. There has already been significant progress in the field of cell-based therapies, with the clinical application for SCI, currently in phase II of the clinical trial. Stem cells(e.g., induced pluripotent stem cells, fetal stem cells, human embryonic stem cells, and olfactory ensheathing cells) are certainly not to be considered the panacea for neural repair but, especially when combined with rehabilitation or other combinatorial approaches using the help of nanotechnology, they seem to be the source of some of the most promising and clinical translatable cell-based therapies that could help solving impactful problems on neural repair.     

Treatment of spinal cord injury by transplantation of fetal neural precursor cells engineered to express BMP inhibitor

Spontaneous recovery after spinal cord injury is limited. Transplantation of neural precursor cells (NPCs) into lesioned adult rat spinal cord results in only partial functional recovery, and most transplanted cells tend to differentiate predominantly into astrocytes. In order to improve functional recovery after transplantation, it is important that transplanted neural precursor cells appropriately differentiate into cell lineages required for spinal cord regeneration. In order to modulate the fate of transplanted cells, we advocate transplanting gene-modified neural precursor cells. We demonstrate that gene modification to inhibit bone morphogenetic protein (BMP) signaling by noggin expression promoted differentiation of neural precursor cells into neurons and oligodendrocytes, in addition to astrocytes after transplantation. Furthermore, functional recovery of the recipient mice with spinal cord injury was observed when noggin-expressing neural precursor cells were transplanted. These observations suggest that gene-modified neural precursor cells that express molecules involved in cell fate modulation could improve central nervous system (CNS) regeneration.     

Synergistic effects of bone marrow stromal cells and a Rho kinase (ROCK) inhibitor,Fasudil on axon regeneration in rat spinal cord injury

Transplanted bone marrow stromal cells (BMSC) promote functional recovery after spinal cord injury (SCI) through multiple mechanisms. A Rho kinase inhibitor, Fasudil also enhances axonal regeneration. This study was aimed to evaluate whether combination therapy of BMSC transplantation and Fasudil further enhances axonal regeneration and functional recovery in rats subjected to SCI. Fasudil or vehicle was injected for 2 weeks. BMSC or vehicle transplantation into the rostral site of SCI was performed at 7 days after injury. Neurological symptoms were assessed throughout the experiments. Fluoro‐Ruby was injected into the dorsal funiculus of the rostral site of SCI at 63 days after injury. The fate of the transplanted BMSC was examined using immunohistochemistry. BMSC transplantation significantly increased the number of Fluoro‐Ruby ‐labeled fibers of the dorsal corticospinal tracts at the caudal site of SCI, enhancing functional recovery of the hind limbs. Some of the engrafted BMSC were positive for Fluoro‐Ruby, neuronal specific nuclear protein and microtubule‐associated protein‐2, suggesting that they acquired neuronal phenotypes and built synaptic connection with the host's neural circuits. Fasudil treatment also improved axonal continuity, but did not promote functional recovery. Combination therapy dramatically increased the number of Fluoro‐Ruby‐labeled fibers of the dorsal corticospinal tracts at the caudal site of SCI, but did not further boost the therapeutic effects on locomotor function by BMSC transplantation. The findings suggest that BMSC transplantation and Fasudil provide synergistic effects on axon regeneration after SCI, although further studies would be necessary to further enhance functional recovery.     

Neuronal stem cells

Stem cells are self regenerating multipotential cells, found in the human brain which have the potential to differentiate into neurons, astrocytes and oligodendrocytes, and to self renew sufficiently to provide adequate number of cells in the brain. Neural stem cell grafts have been studied in a variety of animal models for various diseases like metabolic disorders, muscular dystrophies, neurodegenerative disorders, spinal cord repair, brain tumors and demyelinating disease. Stem cells may be derived from autologus, allogeneic or xenogenic sources. Histocompatibility is prerequisite for transplantation of allogeneic stem cells. Fetal tissue is the best current tissue source for human neural stem cells, however ethical issues are a major concern. Thus the prospect that stem cells could potentially be used to promote neurogenesis following injury and disease may seem attractive, yet the inherent problems associated with isolation and rejection in case of stem cells from another source, the potential to form tumors and ethical issues are the major challenges.     

The emerging role of epigenetics in stroke: III. Neural stem cell biology and regenerative medicine

The transplantation of exogenous stem cells and the activation of endogenous neural stem and progenitor cells (NSPCs) are promising treatments for stroke. These cells can modulate intrinsic responses to ischemic injury and may even integrate directly into damaged neural networks. However, the neuroprotective and neural regenerative effects that can be mediated by these cells are limited and may even be deleterious. Epigenetic reprogramming represents a novel strategy for enhancing the intrinsic potential of the brain to protect and repair itself by modulating pathologic neural gene expression and promoting the recapitulation of seminal neural developmental processes. In fact, recent evidence suggests that emerging epigenetic mechanisms are critical for orchestrating nearly every aspect of neural development and homeostasis, including brain patterning, neural stem cell maintenance, neurogenesis and gliogenesis, neural subtype specification, and synaptic and neural network connectivity and plasticity. In this review, we survey the therapeutic potential of exogenous stem cells and endogenous NSPCs and highlight innovative technological approaches for designing, developing, and delivering epigenetic therapies for targeted reprogramming of endogenous pools of NSPCs, neural cells at risk, and dysfunctional neural networks to rescue and restore neurologic function in the ischemic brain.     

Neurochemical correlates of differential neuroprotection by long-term dietary creatine supplementation

Macrophages/microglia are implicated in spinal cord injury but their precise role in the process is not clear. Our previous studies have reported that radial glia (RG) possess properties of neural stem cells and remerged after central nervous system (CNS) injury which may play an important role in neural repair and regeneration. In the present study, we examined the expression of ED1 (a specific marker for activated macrophages/microglia) and RG in a spinal cord injury (SCI) model and detected the activation at 1, 4, 8, and 12 weeks in both dorsal funiculus and ventral white matter after SCI. For both ED1-positive cells and RG cells, there was a gradual increase in density and in number from 1 to 4 weeks followed by down-regulation up to 12 weeks after injury. The morphologies of macrophages and radial glia were different. However, some ED1-positive cells were also stained by RG marker. These results suggest that macrophages may have some lineage to radial glial cells.