Locomotor Recovery Research Articles

Silencing TAK1 reduces MAPKs-MMP2/9 expression to reduce inflammation-driven neurohistological disruption post spinal cord injury

Microglia activation post traumatic spinal cord injury (SCI) provokes accumulation of inflammatory metabolites, leading to increasing neurological disruption. Our previous studies demonstrated that blocking MAPKs pathway mitigated microglia inflammatory activation and prevented cords from neuroinflammation-induced secondary injury. Transforming growth factor-β-activated kinase 1 (TAK1) is an upstream gate regulating activation of MAPKs signaling. To validate the therapeutic effect of TAK1 inhibition in neuroinflammation post SCI, in the current study, cultures of microglia BV2 line was undergone lipopolysaccharide (LPS) stimulation in the presence of TAK1 inhibitor 5Z-7-Oxozeaenol (ZO), LPS, or control. LPS triggered inflammatory level, cell migration, and matrix metalloproteinase (MMP) 2/9 production, which was reduced in ZO-treated cultures. TAK1 inhibition by ZO also decreased activation of MAPKs pathway, indicating that ZO-mediated alleviation of neuroinflammation is likely modulated via TAK1/MAPKs axis. In vivo, neuroinflammatory level and tissue destruction were assessed in adult male mice that were undergone SCI by mechanical trauma, and treated with ZO by intraperitoneal injection. Compared with SCI mice, ZO-treated mice exhibited less microglia pro-inflammatory activation and accumulation adjacent to injured core linked to reduced MMP2/9 expression, leading to minor tissue damage and better locomotor recovery. To sum up, the obtained data proved that in the early phase post SCI, TAK1 inhibition impedes microglia biological activities including activation, enzymatic synthesis, and migration via downregulation of MAPKs pathway, and the effects may be accurately characterized as potent anti-inflammation.

Exosomes of MSCs target M2-type Macrophages to promote TGF-β-Dependent Microvascular Stabilization and Functional Recovery in Spinal Cord Injury

Abstract Intravenous (IV) infusion of mesenchymal stromal cells (MSC) stabilizes the blood-spinal cord barrier and improves functional neurological recovery after spinal cord injury (SCI). However, the MSCs do not traffic to the injury site, but rather lodge primarily in the lungs for a few days. Here, groups of 8 young Sprague Dawley rats received 2 x 10>6 MSCs, their derived exosomes (MSC-exos, 2 x 10>10). in single dose or dividing that dose over 3 days starting on the 10th day following severe contusive SCI, or vehicle control. Locomotion, cell targeting, expression of TGF-β, TGF-β-R, vascular proteins and permeability were determined at 3, 7 and 14 days after treatments. We report that MSC-exos are released in vivo by infused MSCs, distribute systemically, and at the injury site specifically associate with M2-type macrophages. While a single MSC infusion resulted in significant improvement in locomotor recovery, fractionated dosing of MSC-exos over three days was required to achieve similar extent of therapeutic effects as infusion of the MSCs. Both MSCs and fractionated doses of MSC-exos increased numbers and differentiation of M2-type macs expressing TGF-β, with increased accompanying expression of TGF-β receptors and tight junction proteins in the neighboring microvascular, resulting in reduction in blood spinal cord barrier vascular permeability. SUMMARY: In SCI, IV infused MSCs release MSC-exos in vivo over time that target lesional M2-macs to increase their TGF-β production and further induce TGF-β signaling pathways in the local vasculature to mediate therapeutic effects, likely by release of locally active secondary exosomes transferring miRNAs that induce TGF-β pathways in the neighboring micro vasculature to promote healing.

O‐GlcNAc Transferase OGT‐1 and the Ubiquitin Ligase EEL‐1 Modulate Seizure Susceptibility in C. elegans

Neurodevelopmental disorders such as autism and epilepsy have been linked to an imbalance of excitation and inhibition (E/I) in the central nervous system. The simplicity and tractability of C. elegans allows our electroconvulsive seizure (ES) assay to be used as a behavioral readout of the locomotor circuit and neuronal function. C. elegans possess conserved nervous system features such as gamma-aminobutyric acid (GABA) and GABA receptors in inhibitory neurotransmission, and acetylcholine (Ach) and acetylcholine receptors in excitatory neurotransmission. Our previously published data has shown that decreasing inhibition in the motor circuit, via GABAergic manipulation, will extend the time of locomotor recovery following ES. Similarly, mutations in a HECT E3 ubiquitin ligase called EEL-1 leads to impaired GABAergic transmission, E/I imbalance and altered sensitivity to ES. Mutations in the human ortholog of EEL-1, called HUWE1, are associated with both syndromic and non-syndromic intellectual disability. Both EEL-1 and its previously established binding protein, OGT-1, are expressed in GABAergic motor neurons, localize to GABAergic presynaptic terminals, and function in parallel to regulate GABA neuron function. In this study, we tested behavioral responses to ES in wildtype, ogt-1, eel-1 and ogt-1; eel-1 double mutants. Both single null mutants of OGT-1 and EEL-1 proteins have decreased inhibitory GABAergic neuron function and increased ES sensitivity. Consistent with EEL-1 and OGT-1 functioning in parallel pathways, ogt-1; eel-1 double mutants showed enhanced ES susceptibility. Expression of OGT-1 in the C. elegans nervous system rescued enhanced ES defects in ogt-1; eel-1 double mutants. Our C. elegans ES seizure assay was first to model a human X-linked Intellectual Disorder (XLID) associated with epilepsy and suggests a potential novel role for the OGT-1/EEL-1 complex in seizure susceptibility.

The CatWalk XT® Gait Analysis Is Closely Correlated with Tissue Damage after Cervical Spinal Cord Injury in Rats

Objective and consistent assessment of locomotion recovery remains challenging in rodent spinal cord injury (SCI). We, therefore, studied the validity and relevance of the CatWalk XT® gait analysis as a tool for assessing functional outcome in a clinically relevant cervical SCI model in rats. In total, 20 Wistar rats were randomly assigned to either a C6 clip compression/contusion SCI or a sham laminectomy. Locomotion recovery was assessed weekly using the CatWalk XT® gait analysis and the BBB open field score. Six weeks after SCI, the percentage of preserved spinal cord tissue was measured by glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) staining. Statistical analyses were performed to assess the correlation of the BBB and the percentage of preserved tissue with 30 different CatWalk XT® parameters. SCI caused a bilateral and significant functional impairment in all studied CatWalk XT® parameters. Similar to the BBB, a significant spontaneous recovery could be observed in most of the CatWalk XT® parameters in the following weeks. Correlation between the hindlimb CatWalk XT® parameters and the BBB was good (53% of r values > 0.6) while the correlation between the forelimb and the hindlimb CatWalk XT® parameters and the percentage of preserved tissue was even stronger (83% of r values > 0.6). The CatWalk XT® gait analysis is closely correlated with tissue damage after cervical contusion/compression SCI and can be used as an objective and consistent tool for assessing locomotion recovery.

Liver inflammation at the time of spinal cord injury enhances intraspinal pathology, liver injury, metabolic syndrome and locomotor deficits

The current high obesity rates mean that neurological injuries are increasingly sustained on a background of systemic pathology, including liver inflammation, which likely has a negative impact on outcomes. Because obesity involves complex pathology, the effect of hepatic inflammation alone on neurological recovery is unknown. Thus, here we used a gain-of-function model to test if liver inflammation worsens outcome from spinal cord injury (SCI) in rats. Results show liver inflammation concomitant with SCI exacerbated intraspinal pathology and impaired locomotor recovery. Hepatic inflammation also potentiated SCI-induced non-alcoholic steatohepatitis (NASH), endotoxemia and insulin resistance. Circulating and cerebrospinal levels of the liver-derived protein Fetuin-A were higher in SCI rats with liver inflammation, and, when microinjected into intact spinal cords, Fetuin-A caused macrophage activation and neuron loss. Thus, liver inflammation functions as a disease modifying factor to impair recovery from SCI, and Fetuin-A is a potential neuropathological mediator. Since SCI alone induces acute liver inflammation, the liver may be a novel clinical target for improving recovery from SCI.

Combinatrial treatment of anti-High Mobility Group Box-1 monoclonal antibody and epothilone B improves functional recovery after spinal cord contusion injury

Spinal cord injury (SCI) causes motor and sensory deficits and is currently considered an incurable disease. We have previously reported that administration of anti-High Mobility Group Box-1 monoclonal antibody (anti-HMGB1 mAb) preserved lesion area and improved locomotion recovery in mouse model of SCI. In order to further enhance the recovery, we here examined combinatorial treatment of anti-HMGB1 mAb and epothilone B (Epo B), which has been reported to promote axon regeneration. This combinatorial treatment significantly increased hindlimb movement compared with anti-HMGB1 mAb alone, although Epo B alone failed to increase functional recovery. These results are in agreement with that anti-HMGB1 mAb alone was able to decrease the lesion area spreading and increase the surviving neuron numbers around the lesion, whereas Epo B facilitated axon outgrowth only in combination with anti-HMGB1 mAb, suggesting that anti-HMGB1 mAb-dependent tissue preservation is necessary for Epo B to exhibit its therapeutic effect. Taken together, the combinatorial treatment can be considered as a novel and clinically applicable strategy for SCI.

PD-L1 Improves Motor Function and Alleviates Neuropathic Pain in Male Mice After Spinal Cord Injury by Inhibiting MAPK Pathway.

BackgroundTraumatic spinal cord injury (SCI) causes severe motor dysfunction and persistent central neuropathic pain (Nep), which has not yet been effectively cured. Programmed cell death ligand-1 (PD-L1) is typically produced by cancer cells and contributes to the immune-suppressive in tumor microenvironment. However, the role of PD-L1 in regulating inflammatory response and Nep after SCI remains unclear. A growing amount of researches have begun to investigate the effect of PD-L1 on macrophages and microglia in recent years. Considering the pivotal role of macrophages/microglia in the inflammatory response after SCI, we proposed the hypothesis that PD-L1 improved the recovery of locomotor and sensory functions after SCI through regulating macrophages and microglia.MethodsThe mice SCI model was established to determine the changes in expression patterns of PD-L1. Meanwhile, we constructed PD-L1 knockout mice to observe differences in functional recovery and phenotypes of macrophages/microglia post-SCI.ResultsIn present study, PD-L1 was significantly upregulated after SCI and highly expressed on macrophages/microglia at the injury epicenter. PD-L1 knockout (KO) mice showed worse locomotor recovery and more serious pathological pain compared with wild-type (WT) mice. Furthermore, deletion of PD-L1 significantly increased the polarization of M1-like macrophages/microglia. Mechanistic analysis revealed that PD-L1 may improve functional outcomes following SCI by inhibiting phosphorylation of p38 and ERK1/2.ConclusionsOur observations implicate the involvement of PD-L1 in recovery of SCI and provide a new treatment strategy for the prevention and treatment of this traumatic condition.

FDA-approved 5-HT1F receptor agonist lasmiditan induces mitochondrial biogenesis and enhances locomotor and blood-spinal cord barrier recovery after spinal cord injury

Vascular and mitochondrial dysfunction are well-established consequences of spinal cord injury (SCI). Evidence suggests mitigating these dysfunctions may be an effective approach in treating SCI. The goal of this study was to elucidate if mitochondrial biogenesis (MB) induction with a new, selective and FDA-approved 5-hydroxytryptamine receptor 1F (5-HT1F) receptor agonist, lasmiditan, can stimulate locomotor recovery and restoration of the blood-spinal cord barrier (BSCB) after SCI. Female C57BL/6 J mice were subjected to moderate SCI using a force-controlled impactor-induced contusion model followed by daily administration of lasmiditan (0.1 mg/kg, i.p.) beginning 1 h after injury. In the naïve spinal cord, electron microscopy revealed increased mitochondrial density and mitochondrial area, as well as enhanced mitochondrial DNA content. FCCP-uncoupled oxygen consumption rate (OCR), a functional marker of MB, was also increased in the naïve spinal cord following lasmiditan treatment. We observed disrupted mitochondrial DNA content, PGC-1α levels and FCCP-OCR in the injury site 3d after SCI. Lasmiditan treatment attenuated, and in some cases restored these deficits. Lasmiditan treatment also resulted in increased locomotor capability as early as 7d post-SCI, with treated mice reaching a Basso-Mouse Scale score of 3.3 by 21d, while vehicle-treated mice exhibited a score of 2.0. Integrity of the BSCB was assessed using Evans Blue dye extravasation. While SCI increased dye extravasation at 3d and 7d, dye accumulation in the spinal cord of lasmiditan-treated mice was attenuated 7d post-SCI, suggesting accelerated BSCB recovery. Finally, lasmiditan treatment resulted in decreased lesion volume and spared myelinated tissue 7d post-SCI. Collectively, these data reveal that 5-HT1F receptor agonist-induced MB using the FDA-approved drug lasmiditan may be an effective therapeutic strategy for the treatment of SCI.

Hypoxia-inducible factor prolyl hydroxylase domain (PHD) inhibition after contusive spinal cord injury does not improve locomotor recovery

Traumatic spinal cord injury (SCI) is a devastating neurological condition that involves both primary and secondary tissue loss. Various cytotoxic events including hypoxia, hemorrhage and blood lysis, bioenergetic failure, oxidative stress, endoplasmic reticulum (ER) stress, and neuroinflammation contribute to secondary injury. The HIF prolyl hydroxylase domain (PHD/EGLN) family of proteins are iron-dependent, oxygen-sensing enzymes that regulate the stability of hypoxia inducible factor-1α (HIF-1α) and also mediate oxidative stress caused by free iron liberated from the lysis of blood. PHD inhibition improves outcome after experimental intracerebral hemorrhage (ICH) by reducing activating transcription factor 4 (ATF4)-driven neuronal death. As the ATF4-CHOP (CCAAT-enhancer-binding protein homologous protein) pathway plays a role in the pathogenesis of contusive SCI, we examined the effects of PHD inhibition in a mouse model of moderate T9 contusive SCI in which white matter damage is the primary driver of locomotor dysfunction. Pharmacological inhibition of PHDs using adaptaquin (AQ) moderately lowers acute induction of Atf4 and Chop mRNAs and prevents the acute decline of oligodendrocyte (OL) lineage mRNAs, but does not improve long-term recovery of hindlimb locomotion or increase chronic white matter sparing. Conditional genetic ablation of all three PHD isoenzymes in OLs did not affect Atf4, Chop or OL mRNAs expression levels, locomotor recovery, and white matter sparing after SCI. Hence, PHDs may not be suitable targets to improve outcomes in traumatic CNS pathologies that involve acute white matter injury.

Dual motor cortex and spinal cord neuromodulation improves rehabilitation efficacy and restores skilled locomotor function in a rat cervical contusion injury model

Motor recovery after spinal cord injury is limited due to sparse descending pathway axons caudal to the injury. Rehabilitation is the primary treatment for paralysis in humans with SCI, but only produces modest functional recovery. Here, we determined if dual epidural motor cortex (M1) intermittent theta burst stimulation (iTBS) and cathodal transcutaneous spinal direct stimulation (tsDCS) enhances the efficacy of rehabilitation in improving motor function after cervical SCI. iTBS produces CST axon sprouting and tsDCS enhances M1-evoked spinal activity and muscle contractions after SCI. Rats were trained to perform the horizontal ladder task. Animals received a moderate midline C4 contusion, producing bilateral forelimb impairments. After 2 weeks, animals either received 10 days of iTBS+tsDCS or no stimulation; subsequently, all animals received 6 weeks of daily rehabilitation on the horizontal ladder task. Lesion size was not different in the two animal groups. Rehabilitation alone improved performance by a 22% reduction in skilled locomotion error rate, whereas stimulation+rehabilitation was markedly more effective (52%), and restored error rate to pre-injury levels. Stimulation+rehabilitation significantly increased CST axon length caudal to the injury and the amount of ventral horn label was positively correlated with functional improvement. The stimulation+rehabilitation group had significantly less proprioceptive afferent terminal labelling in the intermediate zone and fewer synapses on motoneurons . Afferent fiber terminal labeling was negatively correlated with motor recovery. Thus, the dual neuromodulation protocol promotes adaptive plasticity in corticospinal and proprioceptive afferents networks after contusion SCI, leading to enhanced rehabilitation efficacy and recovery of skilled locomotion.

Wireless Epidural Electrical Stimulation in Combination With Serotonin Agonists Improves Intraspinal Metabolism in Spinal Cord Injury Rats

ObjectivesThe combination of epidural electrical stimulation (EES) and serotonin agonists (5-HTA) effectively restores rhythmic lower-limb movements and improves intraspinal hemodynamics after spinal cord injury (SCI). Nonetheless, whether EES + 5-HTA improves intraspinal metabolism remains unclear. The present study aimed to evaluate the effects of EES + 5-HTA on intraspinal metabolism in SCI rats. Materials and MethodsWireless EES (WEES) implantation with complete T8 transection was performed in SCI rats. Electrodes were placed at the T12 and L2 vertebral levels. After rest for a week, the SCI rats received 11 weeks of WEES + 5-HTA treatment and treadmill training. WEES was switched off after each daily training. Locomotor function was evaluated by motion capture at week 12. Positron emission tomography–computed tomography was conducted to evaluate basal metabolism when WEES was switched off and assess task metabolism when WEES was switched on. ResultsWith locomotor recovery after training for 11 weeks, WEES + 5-HTA conjointly improved basal metabolism (vs. each intervention alone; p < 0.05) and linearly modulated task metabolism in a frequency-dependent manner (R2 = 0.8901). Furthermore, 60 Hz of WEES was identified as the threshold for the extensive activation of the spinal cord’s task metabolism below the transection plane (p < 0.05). ConclusionsWEES + 5-HTA could conjointly restore basal metabolism to a healthy level and modulate task metabolism by adjusting the stimulation frequency.

The effect of low-level laser therapy on pathophysiology and locomotor recovery after traumatic spinal cord injuries: a systematic review and meta-analysis.

This study was designed to determine the effective therapeutic parameters and evaluate the regenerative potential of low-level laser therapy (LLLT) after traumatic spinal cord injuries (TSCIs) in animal studies. The EMBASE and MEDLINE databases were searched on October 5, 2019, and followed with an update on January 2, 2021. All animal studies discussing the effect of LLLT on main pathophysiological events after TSCI, including inflammation, axon growth, remyelination, glial scar formation, cavity size, and locomotor recovery, were included. For statistical analysis, we used mean difference with 95% confidence intervals for locomotor recovery. In total, 19 articles were included based on our criteria. The results showed that regardless of laser type, laser beams with a wavelength between 600 and 850 nm significantly suppress inflammation and led inflammatory cells to M2 polarization and wound healing. Also, laser therapy using these wavelengths for more than 2 weeks significantly improved axon regeneration and remyelination. Improvement of locomotor recovery was more efficient using wavelengths less than 700 nm (SMD = 1.21; 95%CI: 0.09, 2.33; p = 0.03), lasers with energy densities less than 100 J/cm2 (SMD = 1.72; 95%CI: 0.84, 2.59; p = 0.0001) and treatment duration between 1 and 2 weeks (SMD = 2.21; 95%CI: 1.24, 3.19; p < 0.00001). The LLLT showed promising potential to modulate pathophysiological events and recovery after TSCI, although there was heterogeneity in study design and reporting methods, which should be considered in future studies.

Neonatal Rats Exhibit a Predominantly Anti-Inflammatory Response following Spinal Cord Injury

It has been reported that children may respond better than adults to a spinal cord injury (SCI) of similar severity. There are known biomechanical differences in the developing spinal cord that may contribute to this “infant lesion effect,” but the underlying mechanisms are unknown. Using immunohistochemistry, we have previously demonstrated a different injury progression and immune cell response after a mild thoracic contusion SCI in infant rats, as compared to adult rats. Here, we investigated the acute inflammatory responses using flow cytometry and ELISA at 1 h, 24 h, and 1 week after SCI in neonatal (P7) and adult (9 weeks) rats, and locomotor recovery was examined for 6 weeks after injury. Adult rats exhibited a pronounced pro-inflammatory response characterized by neutrophils and M1-like macrophage infiltration and Th1 cytokine secretion. Neonatal rats exhibited a decreased pro-inflammatory response characterized by a higher proportion of M2-like macrophages and reduced Th1 cytokine responses, as compared to adults. These results suggest that the initial inflammatory response to SCI is predominantly anti-inflammatory in very young animals.

Severe Spinal Cord Injury in Rats Induces Chronic Changes in the Spinal Cord and Cerebral Cortex Metabolism, Adjusted by Thiamine That Improves Locomotor Performance.

Our study aims at developing knowledge-based strategies minimizing chronic changes in the brain after severe spinal cord injury (SCI). The SCI-induced long-term metabolic alterations and their reactivity to treatments shortly after the injury are characterized in rats. Eight weeks after severe SCI, significant mitochondrial lesions outside the injured area are demonstrated in the spinal cord and cerebral cortex. Among the six tested enzymes essential for the TCA cycle and amino acid metabolism, mitochondrial 2-oxoglutarate dehydrogenase complex (OGDHC) is the most affected one. SCI downregulates this complex by 90% in the spinal cord and 30% in the cerebral cortex. This is associated with the tissue-specific changes in other enzymes of the OGDHC network. Single administrations of a pro-activator (thiamine, or vitamin B1, 1.2 mmol/kg) or a synthetic pro-inhibitor (triethyl glutaryl phosphonate, TEGP, 0.02 mmol/kg) of OGDHC within 15–20 h after SCI are tested as protective strategies. The biochemical and physiological assessments 8 weeks after SCI reveal that thiamine, but not TEGP, alleviates the SCI-induced perturbations in the rat brain metabolism, accompanied by the decreased expression of (acetyl)p53, increased expression of sirtuin 5 and an 18% improvement in the locomotor recovery. Treatment of the non-operated rats with the OGDHC pro-inhibitor TEGP increases the p53 acetylation in the brain, approaching the brain metabolic profiles to those after SCI. Our data testify to an important contribution of the OGDHC regulation to the chronic consequences of SCI and their control by p53 and sirtuin 5.

3D bioprinted neural tissue constructs for spinal cord injury repair

Three-dimensional (3D) bioprinting has emerged as a promising approach to fabricate living neural constructs with anatomically accurate complex geometries and spatial distributions of neural stem cells (NSCs) for spinal cord injury (SCI) repair. The NSC-laden 3D bioprinting, however, still faces some big challenges, such as cumbersome printing process, poor cell viability, and minimal cell-material interaction. To address these issues, we have fabricated NSC-laden scaffolds by 3D bioprinting and explore for the first time their application for in vivo SCI repair. In our strategy, we have developed a novel biocompatible bioink consisting of functional chitosan, hyaluronic acid derivatives, and matrigel. This bioink shows fast gelation (within 20 s) and spontaneous covalent crosslinking capability, facilitating convenient one-step bioprinting of spinal cord-like constructs. Thus-fabricated scaffolds maintain high NSC viability (about 95%), and offer a benign microenvironment that facilitates cell-material interactions and neuronal differentiation for optimal formation of neural network. The in vivo experiment has further demonstrated that the bioprinted scaffolds promoted the axon regeneration and decreased glial scar deposition, leading to significant locomotor recovery of the SCI model rats, which may represent a general and versatile strategy for precise engineering of central nervous system and other neural organs/tissues for regenerative medicine application.

Additive Effects of Environmental Enrichment and Ketamine on Neuropathic Pain Relief by Reducing Glutamatergic Activation in Spinal Cord Injury in Rats.

Spinal cord injury (SCI) impairs mobility and often results in complications like intractable neuropathic pain. A multi-approach management of this chronic pain condition has been encouraged, but little has been explored of the field. Here, we focus on the effect and underlying mechanism of environmental enrichment (EE), which promotes voluntary social and physical activities, combined with a clinical analgesic, ketamine, on SCI-induced neuropathic pain as well as motor dysfunction. We performed T13 spinal hemisection in rats, which induced unilateral motor impairment and neuropathic pain-like behaviors in the hindlimb. Treatment regimen started a week after SCI, which consists of ketamine administration (30 mg kg–1 day–1; intramuscular) for 10 days, or EE housing for 20 days, or their combination. Paw withdrawal response to mechanical and thermal stimuli, motor function, burrowing behaviors, and body weight was monitored. Spinal segments at T13 lesion and L4–L6 were collected for histopathological and protein analyses. The joint treatment of EE and ketamine provided greater relief of pain-like behaviors and locomotor recovery than did either paradigm alone. These improvements were associated with reduced cavitation area, astrogliosis, and perilesional phosphorylation of glutamate N-methyl-D-aspartate receptor (NMDAR). Concurrently, lumbar spinal analysis of NMDAR-linked excitatory markers in hypersensitization showed reduced activation of NMDAR, mitogen-activated protein kinase (MAPK) family, nuclear factor (NF)-κB, interleukin (IL)-1β signaling, and restored excitatory amino acid transporter 2 level. Our data support a better therapeutic efficacy of the combination, EE, and ketamine, in the attenuation of neuropathic pain and motor recovery by reducing spinal glutamatergic activation, signifying a potential multifaceted neurorehabilitation strategy to improve SCI patient outcome.

Evaluation of Early Therapeutic Effect of Bone Marrow Mesenchymal Stem Cells Transplantation on Injured Spinal Cord in Albino Rats by Two Routes

Background: Stem cells have created hope for treatment of obstinate cases as injured spinal cord (ISC).Objective: aims to assess possible early therapeutic effect of bone marrow mesenchymal stem cells (BM-MSCs) on regeneration of ISC and to estimate effective transplantation routes in animal models. Material and Methods: 62 adult male albino rats were used; two rats for BM-MSCs extraction and 60 rats were allocated into three groups. Control group: subjected to ISC, intralesional (IL) group: injected with BM-MSCs via intralesional injection and intravenous (IV) group: injected with BM-MSCs via intravenous injection at 3rd day post cord injury (PCI). Rats were examined to assess motor functional recovery. SC specimens were extracted for histological, morphometric, chemical, Immunological and statistical studies. Results: Tracing BM-SCs of SC, (IL) group versus (IV) group showed higher number of engrafted stem cells at all studied ages with gradual decrease from 1st to 6th week PCI. The MSCs counts in (IL) versus (IV) groups were highly significantly increased at 1st, 3rd weeks but only significantly increased at 6th week. They were concentrated at injury site of SC in (IL) group then extended out rostrally and caudally. In (IV) group, they were dispersed over wider area including injury site indicating their capability to home. The mean cavitation areas in treated versus control groups showed highly significant decrease and the smallest cavitation areas observed were in (IL) group. Also (IL) group showed highest neurotrophic factors expressions than other groups with increasing pattern from 1st to 3rd week then decreased at 6th week. Locomotor recovery scores in treated versus control groups showed highly significant increase with highest improvement in (IV) group. Conclusion: This work concluded that early transplantation of BM-MSCs in ISC gave outstanding improvement. Intravenous route therapy provided highest locomotor recovery while intralesional route gave best histological and neuroprotective outcomes.

Intraspinal Administration of Netrin-1 Promotes Locomotor Recovery after Complete Spinal Cord Transection.

Complete spinal cord lesions interrupt the connection of all axonal projections with their neuronal targets below and above the lesion site. In particular, the interruption of connections with the neurons at lumbar segments after thoracic injuries impairs voluntary body control below the injury. The failure of spontaneous regrowth of transected axons across the lesion prevents the reconnection and reinnervation of the neuronal targets. At present, the only treatment in humans that has proven to promote some degree of locomotor recovery is physical therapy. The success of these strategies, however, depends greatly on the type of lesion and the level of preservation of neural tissue in the spinal cord after injury. That is the reason it is key to design strategies to promote axonal regrowth and neuronal reconnection. Here, we test the use of a developmental axon guidance molecule as a biological agent to promote axonal regrowth, axonal reconnection, and recovery of locomotor activity after spinal cord injury (SCI). This molecule, netrin-1, guides the growth of the corticospinal tract (CST) during the development of the central nervous system. To assess the potential of this molecule, we used a model of complete spinal cord transection in rats, at thoracic level 10-11. We show that in situ delivery of netrin-1 at the epicenter of the lesion: (1) promotes regrowth of CST through the lesion and prevents CST dieback, (2) promotes synaptic reconnection of regenerated motor and sensory axons, and (3) preserves the polymerization of the neurofilaments in the sciatic nerve axons. These anatomical findings correlate with a significant recovery of locomotor function. Our work identifies netrin-1 as a biological agent with the capacity to promote the functional repair and recovery of locomotor function after SCI. These findings support the use of netrin-1 as a therapeutic intervention to be tested in humans.

Effect of fecal microbiota transplantation on neurological restoration in a spinal cord injury mouse model: involvement of brain-gut axis

BackgroundSpinal cord injury (SCI) patients display disruption of gut microbiome, and gut dysbiosis exacerbate neurological impairment in SCI models. Cumulative data support an important role of gut microbiome in SCI. Here, we investigated the hypothesis that fecal microbiota transplantation (FMT) from healthy uninjured mice into SCI mice may exert a neuroprotective effect.ResultsFMT facilitated functional recovery, promoted neuronal axonal regeneration, improved animal weight gain and metabolic profiling, and enhanced intestinal barrier integrity and GI motility in SCI mice. High-throughput sequencing revealed that levels of phylum Firmicutes, family Christensenellaceae, and genus Butyricimonas were reduced in fecal samples of SCI mice, and FMT remarkably reshaped gut microbiome. Also, FMT-treated SCI mice showed increased amount of fecal short-chain fatty acids (SCFAs), which correlated with alteration of intestinal permeability and locomotor recovery. Furthermore, FMT downregulated IL-1β/NF-κB signaling in spinal cord and NF-κB signaling in gut following SCI.ConclusionOur study demonstrates that reprogramming of gut microbiota by FMT improves locomotor and GI functions in SCI mice, possibly through the anti-inflammatory functions of SCFAs.4wtf5ApZ8ToEwi5YEe-D32Video

Optimal Preclinical Conditions for Using Adult Human Multipotent Neural Cells in the Treatment of Spinal Cord Injury.

Stem cell-based therapeutics are amongst the most promising next-generation therapeutic approaches for the treatment of spinal cord injury (SCI), as they may promote the repair or regeneration of damaged spinal cord tissues. However, preclinical optimization should be performed before clinical application to guarantee safety and therapeutic effect. Here, we investigated the optimal injection route and dose for adult human multipotent neural cells (ahMNCs) from patients with hemorrhagic stroke using an SCI animal model. ahMNCs demonstrate several characteristics associated with neural stem cells (NSCs), including the expression of NSC-specific markers, self-renewal, and multi neural cell lineage differentiation potential. When ahMNCs were transplanted into the lateral ventricle of the SCI animal model, they specifically migrated within 24 h of injection to the damaged spinal cord, where they survived for at least 5 weeks after injection. Although ahMNC transplantation promoted significant locomotor recovery, the injection dose was shown to influence treatment outcomes, with a 1 × 106 (medium) dose of ahMNCs producing significantly better functional recovery than a 3 × 105 (low) dose. There was no significant gain in effect with the 3 × 106 ahMNCs dose. Histological analysis suggested that ahMNCs exert their effects by modulating glial scar formation, neuroprotection, and/or angiogenesis. These data indicate that ahMNCs from patients with hemorrhagic stroke could be used to develop stem cell therapies for SCI and that the indirect injection route could be clinically relevant. Moreover, the optimal transplantation dose of ahMNCs defined in this preclinical study might be helpful in calculating its optimal injection dose for patients with SCI in the future.