Convergence of Cells from the Progenitor Fraction of Adult Olfactory Bulb Tissue to Remyelinating Glia in Demyelinating Spinal Cord Lesions

Background

Progenitor cells isolated from adult brain tissue are important tools for experimental studies of remyelination. Cells harvested from neurogenic regions in the adult brain such as the subependymal zone have demonstrated remyelination potential. Multipotent cells from the progenitor fraction have been isolated from the adult olfactory bulb (OB) but their potential to remyelinate has not been studied.

Methodology/Principal Findings

We used the buoyant density gradient centrifugation method to isolate the progenitor fraction and harvest self-renewing multipotent neural cells grown in monolayers from the adult green-fluorescent protein (GFP) transgenic rat OB. OB tissue was mechanically and chemically dissociated and the resultant cell suspension fractionated on a Percoll gradient. The progenitor fraction was isolated and these cells were plated in growth media with serum for 24 hrs. Cells were then propagated in N2 supplemented serum-free media containing b-FGF. Cells at passage 4 (P4) were introduced into a demyelinated spinal cord lesion. The GFP⁺ cells survived and integrated into the lesion, and extensive remyelination was observed in plastic sections. Immunohistochemistry revealed GFP⁺ cells in the spinal cord to be glial fibrillary acidic protein (GFAP), neuronal nuclei (NeuN), and neurofilament negative. The GFP⁺ cells were found among primarily P0⁺ myelin profiles, although some myelin basic protein (MBP) profiles were present. Immuno-electron microscopy for GFP revealed GFP⁺ cell bodies adjacent to and surrounding peripheral-type myelin rings.

Conclusions/Significance

We report that neural cells from the progenitor fraction of the adult rat OB grown in monolayers can be expanded for several passages in culture and that upon transplantation into a demyelinated spinal cord lesion provide extensive remyelination without ectopic neuronal differentiation.     

Serum Thyroid-Stimulating Hormone and Anti-Thyroglobulin Antibody Are Independently Associated with Lesions in Spinal Cord in Central Nervous System Demyelinating Diseases

Transverse myelitis (TM) is associated with neuromyelitis optica (NMO) and multiple sclerosis (MS). Early recognition of useful parameters may be helpful to distinguish their difference. This retrospective study analyzed thyroid parameters from 243 serum samples (relapse = 128; remission = 115) of 178 patients with demyelinating diseases (NMO, n = 25; TM, n = 48; MS, n = 105). The relationship between thyroid and clinical parameters was analyzed. Patients with NMO and TM had a higher frequency of abnormal thyroid-stimulating hormone (TSH), anti-thyroglobulin antibodies (TG-Ab), and antithyroid peroxidase antibody (TPO-Ab) than MS patients (p<0.05). The level of TSH and TG-Ab returned to normal levels after administration of high-dose intravenous methylprednisolone (p<0.05). In 96 patients (NMO, n = 19; TM, n = 25; MS, n = 52) without treatment, serum levels of TSH, TG-Ab and TPO-Ab were significantly different between patients with and without myelitis (p<0.01). Patients positive for aquaporin-4 (AQP4) antibodies showed higher abnormalities of TSH (p = 0.001), TG-Ab (p = 0.004) and TPO-Ab (p<0.0001) levels than AQP4 antibodies negative patients. Logistic regression analyses revealed independent relationships between TSH (odds ratio [OR]  = 33.994; p<0.0001), TG-Ab (OR = 7.703; p = 0.017) and myelitis occurrence in 96 patients at the active stage. In 52 MS patients experiencing their first attack, MS patients with myelitis were associated with TSH abnormalities (OR = 42.778; p<0.0001). This study showed increased abnormalities of thyroid parameters in patients with NMO and TM than in MS patients. MS patients with myelitis also had greater TSH abnormality than in MS patients without myelitis. Abnormal TSH and TG-Ab were independently associated with myelitis occurrence in central nervous system demyelinating disorders.     

Thoracic Rat Spinal Cord Contusion Injury Induces Remote Spinal Gliogenesis but Not Neurogenesis or Gliogenesis in the Brain

After spinal cord injury, transected axons fail to regenerate, yet significant, spontaneous functional improvement can be observed over time. Distinct central nervous system regions retain the capacity to generate new neurons and glia from an endogenous pool of progenitor cells and to compensate neural cell loss following certain lesions. The aim of the present study was to investigate whether endogenous cell replacement (neurogenesis or gliogenesis) in the brain (subventricular zone, SVZ; corpus callosum, CC; hippocampus, HC; and motor cortex, MC) or cervical spinal cord might represent a structural correlate for spontaneous locomotor recovery after a thoracic spinal cord injury. Adult Fischer 344 rats received severe contusion injuries (200 kDyn) of the mid-thoracic spinal cord using an Infinite Horizon Impactor. Uninjured rats served as controls. From 4 to 14 days post-injury, both groups received injections of bromodeoxyuridine (BrdU) to label dividing cells. Over the course of six weeks post-injury, spontaneous recovery of locomotor function occurred. Survival of newly generated cells was unaltered in the SVZ, HC, CC, and the MC. Neurogenesis, as determined by identification and quantification of doublecortin immunoreactive neuroblasts or BrdU/neuronal nuclear antigen double positive newly generated neurons, was not present in non-neurogenic regions (MC, CC, and cervical spinal cord) and unaltered in neurogenic regions (dentate gyrus and SVZ) of the brain. The lack of neuronal replacement in the brain and spinal cord after spinal cord injury precludes any relevance for spontaneous recovery of locomotor function. Gliogenesis was increased in the cervical spinal cord remote from the injury site, however, is unlikely to contribute to functional improvement.     

Serum Lipid Profile in Subjects with Traumatic Spinal Cord Injury

ResultsCases without preserved motor function (AIS A or B) had lower total and HDL cholesterol than the others (-11.4 [-21.5, -1.4] mg/dL total cholesterol and -5.1 [-8.8, -1.4] mg/dL HDL-c), and cases with all-limb involvement had lower total, HDL, and LDL cholesterol than those with only lower-limb involvement (-14.0 [-24.6, -3.4] mg/dL total cholesterol, -4.1 [-8.0, -0.2] mg/dL HDL-c, and -10.0 [-19.7, -0.3] mg/dL LDL-c) (all p<0.05). No association was found between lipid concentrations and time since injury. Concentrations of lipid subfractions and triglycerides in SCI subjects were lower than in sex- and age-stratified values from the reference sample.ConclusionA high degree of neurological involvement in SCI (anatomically higher lesions and AIS A or B) is associated with lower total cholesterol and HDL-c.     

Respiratory Nursing Interventions Following Tracheostomy in Acute Traumatic Cervical Spinal Cord Injury

Tracheostomy is frequently performed in severe cervical spinal cord injury (SCI) patients with the pulmonary dysfunction. A series of respiratory nursing interventions are required to plan tracheostomy removal. Tracheostomy was performed in 29 patients after acute traumatic cervical SCI. A series of respiratory nursing interventions were introduced in these patients after closed tracheostomy and decannulation, including closed tracheostomy tube training, manually assisted cough. Chacheostomy was successfully removed in 21 patients after the respiratory nursing interventions. In contrast, eight patients died from associated injuries. The average time from tracheostomy to decannulation was 40 days (14–104 days), the average time from closed tracheostomy to decannulation was 18.80 ± 13.50 days. Second tracheostomy was performed in one patient after 29 days’ removal due to pulmonary infection. One patient presented with delayed incision healing for 29 days. Closed tracheostomy tube training and manually assisted cough are key factors for tracheostomy removal, although intensive nursing are also needed. The time from tracheostomy to decannulation and from closed tracheostomy to decannulation is increased in case of "late" (>24 h) tracheostomy and longer mechanical ventilation.     

少突胶质前体细胞治疗脊髓损伤的研究进展

脊髓损伤(spinal cord injury,SCI)是一种严重危害人类生命健康的疾病,其发病率呈现逐年上升的趋势,并且治疗较为困难。研究发现脊髓损伤后少突胶质细胞大量死亡,引发脱髓鞘病变,这可能是其难以治疗的原因之一。少突胶质前体细胞(OPCs)为少突胶质细胞的祖细胞,后者是中枢神经系统的成髓鞘细胞。OPCs来源于胚胎发育早期神经管腹侧神经上皮细胞,随着神经管的发育,OPCs逐渐增殖、迁移并分化为成熟OL,参与中枢神经系统轴突髓鞘的形成。随着对OPCs的不断深入研究,发现OPCs移植对SCI有较好的疗效,这可能为SCI患者开辟一条新的治疗途径。本文就OPCs治疗SCI的动物实验研究结果做一综述。     

Response of NADPH-Diaphorase-Exhibiting Neurons in the Medullar Reticular Formation to High Spinal Cord Injury

1. The effect of hemisection of the cervical spinal cord on NADPH-diaphorase staining in the reticular nuclei of the rabbit medulla was investigated using histochemical technique.2. A quantitative assessment of somal and neuropil NADPH-diaphorase staining was made by an image analyzer in a selected area of each reticular nucleus of the rabbit medulla.3. On the 7th postsurgery day, the highest up-regulation of somatic NADPH-diapho- rase staining was observed in regions regulating cardiorespiratory processes; however, the highest increase of neuropil NADPH-diaphorase staining was found in the reticular nuclei modulating the tonus of postural muscles.4. The degeneration of non-NADPH-diaphorase-stained neurons was detected throughout the reticular formation of the medulla, but the extent of neuronal death did not correlate with the up-regulation of the NADPH-diaphorase staining in the reticular nuclei of the medulla.5. The findings provide evidence that NADPH-diaphorase-exhibiting neurons are refractory to the hemisection of the cervical spinal cord and that the neuronal up-regulation of NADPH-diaphorase at the medullar level is probably not a causative factor leading to the death of the reticulospinal neurons.     

Modeling the Patient Journey from Injury to Community Reintegration for Persons with Acute Traumatic Spinal Cord Injury in a Canadian Centre

Background

A patient’s journey through the health care system is influenced by clinical and system processes across the continuum of care.

Methods

To inform optimized access to care and patient flow for individuals with traumatic spinal cord injury (tSCI), we developed a simulation model that can examine the full impact of therapeutic or systems interventions across the care continuum for patients with traumatic spinal cord injuries. The objective of this paper is to describe the detailed development of this simulation model for a major trauma and a rehabilitation centre in British Columbia (BC), Canada, as part of the Access to Care and Timing (ACT) project and is referred to as the BC ACT Model V1.0.

Findings

To demonstrate the utility of the simulation model in clinical and administrative decision-making we present three typical scenarios that illustrate how an investigator can track the indirect impact(s) of medical and administrative interventions, both upstream and downstream along the continuum of care. For example, the model was used to estimate the theoretical impact of a practice that reduced the incidence of pressure ulcers by 70%. This led to a decrease in acute and rehabilitation length of stay of 4 and 2 days, respectively and a decrease in bed utilization of 9% and 3% in acute and rehabilitation.

Conclusion

The scenario analysis using the BC ACT Model V1.0 demonstrates the flexibility and value of the simulation model as a decision-making tool by providing estimates of the effects of different interventions and allowing them to be objectively compared. Future work will involve developing a generalizable national Canadian ACT Model to examine differences in care delivery and identify the ideal attributes of SCI care delivery.     

NADPH Oxidase and Superoxide-Producing Associates in Cells of the Spinal Cord and Bone Marrow in Diabetic Rats with Spinal Cord Injury

Neurophysiology - For the first time, a method for isolation and purification of the total fraction of NOX isoforms (NOX1 + NOX2) and the total fraction of O2 – producing stable associates of...     

Biomarkers in Spinal Cord Injury: from Prognosis to Treatment

Spinal cord injury (SCI) is considered an incurable condition, having a heterogenous recovery and uncertain prognosis. Therefore, a reliable prediction of the improvement in the acute phase could benefit patients. Physicians are unanimous in insisting that at the initial damage of the spinal cord (SC), the patient should be carefully evaluated in order to help selecting an appropriate neuroprotective treatment. However, currently, neurologic impairment after SCI is measured and classified by functional examination. The identification of prognostic biomarkers of SCI would help to designate SC injured patients and correlate to diagnosis and correct treatment. Some proteins have already been identified as good potential biomarkers of central nervous system injury, both in cerebrospinal fluid (CSF) and blood serum. However, the problem for using them as biomarkers is the way they should be collected, as acquiring CSF through a lumbar puncture is significantly invasive. Remarkably, microRNAs (miRNAs) have emerged as interesting biomarker candidates because of their stability in biological fluids and their tissue specificity. Several miRNAs have been identified to have their expressions altered in SCI in many animal models, making them promising candidates as biomarkers after SCI. Moreover, there are yet no effective therapies for SCI. It is already known that altered lysophospholipids (LPs) signaling are involved in the biology of disorders, such as inflammation. Reports have demonstrated that LPs when locally distributed can regulate SCI repair and key secondary injury processes such as apoptosis and inflammation, and so could become in the future new therapeutic approaches for treating SCI.     

Dietary Supplementation with Organoselenium Accelerates Recovery of Bladder Expression,but Does Not Improve Locomotor Function,following Spinal Cord Injury

Selenium is an essential element required for activity of several antioxidant enzymes, including glutathione peroxidase. Because of the critical role of the antioxidant system in responding to traumatic events, we hypothesized that dietary selenium supplementation would enhance neuroprotection in a rodent model of spinal cord injury. Rats were maintained on either a control or selenium-enriched diet prior to, and following, injury. Dietary selenium supplementation, provided as selenized yeast added to normal rat chow, resulted in a doubling of selenium levels in the spinal cord. Dietary selenium reduced the time required for recovery of bladder function following thoracic spinal cord injury. However, this was not accompanied by improvement in locomotor function or tissue sparing.     

Role of Radial Glia in Transformation of the Primitive Lumen to the Central Canal in the Developing Rat Spinal Cord

In the last quarter of the embryonic development of rat and shortly after a termination of neurogenesis, the transformation of the spinal cord primitive lumen (pL) to the central canal (CC) occurs. In this work, we show that this phenomenon is not an insignificant event but it is directly associated with the processes of gliogenesis. Using a light microscopy and immunohistochemistry, we monitored the development of the rat embryonic spinal cord from the end of the neurogenesis on the embryonic day 17 until the maturation of the spinal cord during the first postnatal weeks. Our observations demonstrate the importance of the transformation of the pL to the CC and its connection with gliogenesis, and the mechanism of this transformation is proposed. It is found that a segregation of the glutamate transporter (GLAST) immunopositive cells from the alar plates and transformation of the radial glial cells to the fibrous and protoplasmic astrocytes play presumably a key role in the diminution of the ventricular zone. Results indicate that the very transformation and migration of the radial glial cells during gliogenesis could result in a transformation of the pL to the CC.     

Intraspinal Cell Transplantation for Targeting Cervical Ventral Horn in Amyotrophic Lateral Sclerosis and Traumatic Spinal Cord Injury

Respiratory compromise due to phrenic motor neuron loss is a debilitating consequence of a large proportion of human traumatic spinal cord injury (SCI) cases ¹ and is the ultimate cause of death in patients with the motor neuron disorder, amyotrophic laterals sclerosis (ALS) ².ALS is a devastating neurological disorder that is characterized by relatively rapid degeneration of upper and lower motor neurons. Patients ultimately succumb to the disease on average 2-5 years following diagnosis because of respiratory paralysis due to loss of phrenic motor neuron innnervation of the diaphragm ³. The vast majority of cases are sporadic, while 10% are of the familial form. Approximately twenty percent of familial cases are linked to various point mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene on chromosome 21 ⁴. Transgenic mice ^4,5 and rats ⁶ carrying mutant human SOD1 genes ^{(G93A, G37R, G86R, G85R)} have been generated, and, despite the existence of other animal models of motor neuron loss, are currently the most highly used models of the disease.Spinal cord injury (SCI) is a heterogeneous set of conditions resulting from physical trauma to the spinal cord, with functional outcome varying according to the type, location and severity of the injury ⁷. Nevertheless, approximately half of human SCI cases affect cervical regions, resulting in debilitating respiratory dysfunction due to phrenic motor neuron loss and injury to descending bulbospinal respiratory axons ¹. A number of animal models of SCI have been developed, with the most commonly used and clinically-relevant being the contusion ⁸.Transplantation of various classes of neural precursor cells (NPCs) is a promising therapeutic strategy for treatment of traumatic CNS injuries and neurodegeneration, including ALS and SCI, because of the ability to replace lost or dysfunctional CNS cell types, provide neuroprotection, and deliver gene factors of interest ⁹.Animal models of both ALS and SCI can model many clinically-relevant aspects of these diseases, including phrenic motor neuron loss and consequent respiratory compromise ^10,11. In order to evaluate the efficacy of NPC-based strategies on respiratory function in these animal models of ALS and SCI, cellular interventions must be specifically directed to regions containing therapeutically relevant targets such as phrenic motor neurons. We provide a detailed protocol for multi-segmental, intraspinal transplantation of NPCs into the cervical spinal cord ventral gray matter of neurodegenerative models such as SOD1^G93A mice and rats, as well as spinal cord injured rats and mice ¹¹.Download video file.^{(63M, mov)}     

Stem Cell Transplantation in Traumatic Spinal Cord Injury: A Systematic Review and Meta-Analysis of Animal Studies

Spinal cord injury (SCI) is a devastating condition that causes substantial morbidity and mortality and for which no treatments are available. Stem cells offer some promise in the restoration of neurological function. We used systematic review, meta-analysis, and meta-regression to study the impact of stem cell biology and experimental design on motor and sensory outcomes following stem cell treatments in animal models of SCI. One hundred and fifty-six publications using 45 different stem cell preparations met our prespecified inclusion criteria. Only one publication used autologous stem cells. Overall, allogeneic stem cell treatment appears to improve both motor (effect size, 27.2%; 95% Confidence Interval [CI], 25.0%–29.4%; 312 comparisons in 5,628 animals) and sensory (effect size, 26.3%; 95% CI, 7.9%–44.7%; 23 comparisons in 473 animals) outcome. For sensory outcome, most heterogeneity between experiments was accounted for by facets of stem cell biology. Differentiation before implantation and intravenous route of delivery favoured better outcome. Stem cell implantation did not appear to improve sensory outcome in female animals and appeared to be enhanced by isoflurane anaesthesia. Biological plausibility was supported by the presence of a dose–response relationship. For motor outcome, facets of stem cell biology had little detectable effect. Instead most heterogeneity could be explained by the experimental modelling and the outcome measure used. The location of injury, method of injury induction, and presence of immunosuppression all had an impact. Reporting of measures to reduce bias was higher than has been seen in other neuroscience domains but were still suboptimal. Motor outcomes studies that did not report the blinded assessment of outcome gave inflated estimates of efficacy. Extensive recent preclinical literature suggests that stem-cell–based therapies may offer promise, however the impact of compromised internal validity and publication bias mean that efficacy is likely to be somewhat lower than reported here.     

Electroacupuncture and Curcumin Promote Oxidative Balance and Motor Function Recovery in Rats Following Traumatic Spinal Cord Injury

Neurochemical Research - Spinal cord injury (SCI) is a condition that puts the patient’s life at risk in the acute phase and, during the chronic stage, results in permanent deficits in motor,...     

Human Umbilical Cord Mesenchymal Stem Cells Derived Exosomes Promote Neurological Function Recovery in a Rat Spinal Cord Injury Model

Neurochemical Research - Spinal cord injury (SCI) often leads to personal and social-economic consequences with limited therapeutic options. Exosomes derived from human umbilical cord mesenchymal...     

Transplantation of Oligodendrocyte Precursor Cells Improves Locomotion Deficits in Rats with Spinal Cord Irradiation Injury

Demyelination contributes to the functional impairment of irradiation injured spinal cord. One potential therapeutic strategy involves replacing the myelin-forming cells. Here, we asked whether transplantation of Olig2⁺-GFP⁺-oligodendrocyte precursor cells (OPCs), which are derived from Olig2-GFP-mouse embryonic stem cells (mESCs), could enhance remyelination and functional recovery after spinal cord irradiation injury. We differentiated Olig2-GFP-mESCs into purified Olig2⁺-GFP⁺-OPCs and transplanted them into the rats’ cervical 4–5 dorsal spinal cord level at 4 months after irradiation injury. Eight weeks after transplantation, the Olig2⁺-GFP⁺-OPCs survived and integrated into the injured spinal cord. Immunofluorescence analysis showed that the grafted Olig2⁺-GFP⁺-OPCs primarily differentiated into adenomatous polyposis coli (APC⁺) oligodendrocytes (54.6±10.5%). The staining with luxol fast blue, hematoxylin & eosin (LFB/H&E) and electron microscopy demonstrated that the engrafted Olig2⁺-GFP⁺-OPCs attenuated the demyelination resulted from the irradiation. More importantly, the recovery of forelimb locomotor function was enhanced in animals receiving grafts of Olig2⁺-GFP⁺-OPCs. We concluded that OPC transplantation is a feasible therapy to repair the irradiated lesions in the central nervous system (CNS).     

Synergetic Use of Neural Precursor Cells and Self-assembling Peptides in Experimental Cervical Spinal Cord Injury

Spinal cord injuries (SCI) cause serious neurological impairment and psychological, economic, and social consequences for patients and their families. Clinically, more than 50% of SCI affect the cervical spine¹. As a consequence of the primary injury, a cascade of secondary mechanisms including inflammation, apoptosis, and demyelination occur finally leading to tissue scarring and development of intramedullary cavities^2,3. Both represent physical and chemical barriers to cell transplantation, integration, and regeneration. Therefore, shaping the inhibitory environment and bridging cavities to create a supportive milieu for cell transplantation and regeneration is a promising therapeutic target⁴. Here, a contusion/compression model of cervical SCI using an aneurysm clip is described. This model is more clinically relevant than other experimental models, since complete transection or ruptures of the cord are rare. Also in comparison to the weight drop model, which in particular damage the dorsum columns, circumferential compression of the spinal cord appears advantageous. Clip closing force and duration can be adjusted to achieve different injury severity. A ring spring facilitates precise calibration and constancy of clip force. Under physiological conditions, synthetic self-assembling peptides (SAP) self-assemble into nanofibers and thus, are appealing for application in SCI⁵. They can be injected directly into the lesion minimizing damage to the cord. SAPs are biocompatible structures erecting scaffolds to bridge intramedullary cavities and thus, equip the damaged cord for regenerative treatments. K2(QL)6K2 (QL6) is a novel SAP introduced by Dong et al.⁶ In comparison to other peptides, QL6 self-assembles into β-sheets at neutral pH⁶.14 days after SCI, after the acute stage, SAPs are injected into the center of the lesion and neural precursor cells (NPC) are injected into adjacent dorsal columns. In order to support cell survival, transplantation is combined with continuous subdural administration of growth factors by osmotic micro pumps for 7 days.